WorldWideScience

Sample records for chronology

  1. Chronology. Classroom Focus.

    Science.gov (United States)

    McGoldrick, Neale

    1995-01-01

    Presents a chronology of important dates and events in the struggle for women's rights and women's suffrage. Begins in 1648 with the first call for women's suffrage in Maryland and concludes in 1920 with the passage of the 19th Amendment by Tennessee. (CFR)

  2. Real Wage Chronology

    OpenAIRE

    Amy Peng; Louis N. Christofides

    2009-01-01

    We process information in a large number of Canadian wage contracts, signed over a period of several decades, to generate the long-run history of the real wage for each bargaining pair. We term these hitherto unexamined histories ‘chronologies’. We are able to generate 1574 continuous real wage chronologies and we examine the evolution of the real wage in each case. We explore the influence of productivity growth, the labour relations record of the pair, the influence of industry and region a...

  3. Chronological objects in demographic research

    NARCIS (Netherlands)

    Willekens, F.J.C.

    2013-01-01

    Background: Calendar time, age and duration are chronological objects. They represent an instant or a time period. Age and duration are usually expressed in units with varying lengths. The number of days in a month or a year depends on the position on the calendar. The units are also not homogeneous

  4. The boundary of the chronology violating set

    CERN Document Server

    Minguzzi, E

    2016-01-01

    A sufficiently general definition for the future and past boundaries of the chronology violating region is given. In comparison to previous studies, this work does not assume that the complement of the chronology violating set is globally hyperbolic. The boundary of the chronology violating set is studied and several propositions are obtained which confirm the reasonability of the definition. Some singularity theorems related to chronology violation are considered.

  5. CHRONOLOGICAL INVENTORY OF CHEMISTRY TEACHING

    OpenAIRE

    Laxman S. Bhattar; SWAMINATH L.BHATTAR

    2013-01-01

    The Chronological Research of Chemistry teaching in the science education isinvented by the following pioneer philosophers and they developed the skills abilitieswhich is remarked by the Greek philosophers are socrates and plato (in 116 to 127 BC)given an idea an naturalistic and conceptual thoughts and highlights on water. Chinaphilosophers (365 to 427 BC) Taoism made pioneer of Alchemy used in medicines andtranslation preparation of Au (Gold). Epicurea (341 to 371 to 400 BC) developed kinet...

  6. Chronology of eclipse "San Miao"

    Science.gov (United States)

    Liu, Ci-Yuan

    2001-06-01

    The ancient book "Mozi" (5th century BC) records: "In ancient times, the San Miao tribes were in disarray. The sun rose in the evening...King Yu vanquished them. "King Yu is a prehistoric person living in 23-19th century BC. The strange phenomena "sun rose in evening" was explained as a large solar eclipse at sunset by Pang. Therefore investigations on it may lead to an important progress of Chinese chronology. After an analysis on all similar records in Chinese history, we pay main attention to the relationship of eclipse computations with parameter "c", the long term of earth's rotation rate. We have computed all the solar eclipses in that period by the way similar to that used for investigating the "double dawn" eclipse. By change parameter "c" in reasonable range (28-36 sec/cy2), we have found 11 possible results listed in a table. One figure shows the eclipse maps and relative "double dawn/dusk" areas while another one illustrates how the parameter "c" affects the result. For an exact conclusion of King Yu's chronology, we need further progress from both side: history which may limit the King Yu's period and astronomy which may limit the possible range of parameter "c".

  7. Astronomical arguments in Newton's Chronology

    CERN Document Server

    Naze, Yael

    2012-01-01

    In his Chronology, Newton uses astronomical "evidence" to support its extreme rejuvenation of ancient times. These elements, having a scientific varnish, provide some credibility to the work. They have been fiercely debated for a century, with a gradual undermining of Newton's assumptions. However, this has not dented the prestige of the English scientist. ----- Dans sa Chronologie, Newton utilise des "preuves" astronomiques pour appuyer son rajeunissement extreme des epoques anciennes. Ces elements, au vernis scientifique, donnent une credibilite certaine a l'ensemble. Ils ont donc ete aprement discutes, les debats sapant petit a petit les hypotheses du savant anglais pour finalement porter un coup mortel a l'ensemble. Cela n'a toutefois pas entame le prestige du savant anglais.

  8. Climate wavelet spectrum estimation under chronology uncertainties

    Science.gov (United States)

    Lenoir, G.; Crucifix, M.

    2012-04-01

    Several approaches to estimate the chronology of palaeoclimate records exist in the literature: simple interpolation between the tie points, orbital tuning, alignment on other data... These techniques generate a single estimate of the chronology. More recently, statistical generators of chronologies have appeared (e.g. OXCAL, BCHRON) allowing the construction of thousands of chronologies given the tie points and their uncertainties. These techniques are based on advanced statistical methods. They allow one to take into account the uncertainty of the timing of each climatic event recorded into the core. On the other hand, when interpreting the data, scientists often rely on time series analysis, and especially on spectral analysis. Given that paleo-data are composed of a large spectrum of frequencies, are non-stationary and are highly noisy, the continuous wavelet transform turns out to be a suitable tool to analyse them. The wavelet periodogram, in particular, is helpful to interpret visually the time-frequency behaviour of the data. Here, we combine statistical methods to generate chronologies with the power of continuous wavelet transform. Some interesting applications then come up: comparison of time-frequency patterns between two proxies (extracted from different cores), between a proxy and a statistical dynamical model, and statistical estimation of phase-lag between two filtered signals. All these applications consider explicitly the uncertainty in the chronology. The poster presents mathematical developments on the wavelet spectrum estimation under chronology uncertainties as well as some applications to Quaternary data based on marine and ice cores.

  9. Extravehicular Activity Fact Sheet: An EVA Chronology

    Data.gov (United States)

    National Aeronautics and Space Administration — Walking to Olympus: An EVA Chronology chronicles the 154 EVAs conducted from March 1965 to April 1997. It is intended to make clear the crucial role played by EVA...

  10. Chronological objects in demographic research

    Directory of Open Access Journals (Sweden)

    Frans J. Willekens

    2013-03-01

    Full Text Available BACKGROUND Calendar time, age and duration are chronological objects. They represent an instant or a time period. Age and duration are usually expressed in units with varying lengths. The number of days in a month or a year depends on the position on the calendar. The units are also not homogeneous and the structure influences measurement. One solution, common in demography, is to use units that are large enough for the results not to be seriously affected by differences in length and structure. Another approach is to take the idiosyncrasy of calendars into account and to work directly with calendar dates. The technology that enables logical and arithmetic operations on dates is available. OBJECTIVE To illustrate logical and arithmetic operations on dates and conversions between time measurements. METHODS Software packages include utilities to process dates. I use existing and a few new utilities in R to illustrate operations on dates and conversions between calendar dates and elapsed time since a reference moment or a reference event. Three demographic applications are presented. The first is the impact of preferences for dates and days on demographic indicators. The second is event history analysis with time-varying covariates. The third is microsimulation of life histories in continuous time. CONCLUSIONS The technology exists to perform operations directly on dates, enabling more precise calculations of duration and elapsed time in demographic analysis. It eliminates the need for (a approximations and (b transformations of dates, such as Century Month Code, that are convenient for computing durations but are a barrier to interpretation. Operations on dates, such as the computation of age, should consider time units of varying length.

  11. On the Astronomical Records and Babylonian Chronology

    CERN Document Server

    Gurzadyan, V G

    2000-01-01

    We outline the priority of high quality data of astronomical content as our strategy for the analysis of the ancient astronomical records in the search of the absolute chronology of the Near East in II millennium BC. The correspondingly defined set of data for two lunar eclipses of EAE 20 and 21 tablets linked to Ur III period enables us the choice of eclipses of 27 June 1954 BC and 17 March 1912 BC; here the information on the exit position of the darkening of the lunar disk acts as a crucial informator survived in the records. We then discuss why the 56/64 year Venus cycle cannot be traced in the Venus Tablet and therefore cannot serve as an anchor for the search of chronologies. The month length method is discussed as well. In sum the available data support the Ultra-Low Chronology proposed in the book by H.Gasche, J.A.Armstrong, S.W.Cole and V.G.Gurzadyan, "Dating the Fall of Babylon" (1998) and, particularly, leave no astronomical background for the High Chronology. Ultra-Low Chronology is supported also...

  12. Aging in elderly: Chronological versus photoaging

    Directory of Open Access Journals (Sweden)

    Priya Cinna Durai

    2012-01-01

    Full Text Available Background: Skin is a window to aging changes, a biological reality. There is a dearth of studies regarding the various chronological (intrinsic aging and photoaging (extrinsic changes seen in Asians. This study was undertaken to detect the clinical pattern of aging skin changes and dermatoses seen in the elderly. Materials and Methods: This was a descriptive study conducted on 500 consecutive elderly individuals attending the Dermatology out-patient department. The severity of photoaging was graded using Glogau scale. Results: Most of the population had skin type IV and V. Majority (415, 83% of our cases had chronological aging without photoaging and the remaining 85 (17% individuals had photoaging along with chronological aging. The common skin changes due to chronological aging were thin skin, fine wrinkles, xerosis, and loss of elasticity. Photoaging changes such as dyspigmentation, freckles, thick skin, deep wrinkles, melasma, citrine skin, senile purpura, pseudostellate scar, acrokeratoelastoidosis marginalis, and lentigines were less frequent in our study. Smoking and prolonged sun exposure was the risk factors aggravating photoaging. The most common dermatosis was pruritus in 248 (49.6% individuals, of which 149 (29.8% had pruritus associated with xerosis. Contact dermatitis was more common in males. Fungal infections were frequently seen in females. Seborrhoeic keratosis (253, 50.6% was the most common benign neoplasm more commonly seen in males. Cutaneous malignancies were less common in our study population. Conclusion: Photoaging changes were less common than chronological aging changes in skin type IV. Chronological changes were more frequent in females than males, while photoaging was more frequent in males.

  13. Chronology violation and the Cosmological Argument

    CERN Document Server

    Romero, G E

    2003-01-01

    The Kalam Cosmological Argument is perhaps the most solid and widly discussed argument for a caused creation of the universe. The usual objections to the argument mainly focus on the second premise. In this paper we discuss the dependency of the first premise on the topological structure of the space-time manifold adopted for the underlying cosmological model. It is shown that in chronology-violating space-times the first premise is also violated. The chronology-violation, in turn, requires a massive violation of the so-called energy conditions which could have observational effects that are briefly discussed here. Hence, astronomical observations could be relevant for the validity of the metaphysical argument. In this sense, it is possible to talk of "observational theology".

  14. A chronology of librarianship, 1960-2000

    CERN Document Server

    Wilhite, Jeffrey M

    2009-01-01

    This book covers all areas of library literature that inform the history of librarianship and ranges over multiple continents. Its broad scope lends itself to wide use by scholars and students of library history and library literature. The chronology is presented in a dictionary format and separated into decades. It is complemented by a comprehensive bibliography and both subject and name indexes, which are cross-listed for ease of use.

  15. Criticism of traditional chronology: How long will Scaliger survive?

    Directory of Open Access Journals (Sweden)

    Bukvić Rajko

    2005-01-01

    Full Text Available The paper considers the problems of current state and survival of traditional chronology and history based upon the Scaliger and Petavius books from XVI and XVII centuries. Among many approaches that insist on the need of examination of that chronology, developed at first in Russia, but also in Germany, England, USA and other countries, author focuses to the investigation of Fomenko and his collaborators, but also the Khronotron group. Both these groups, like many others critics of current chronology, as their inspirators and predecessors mark Newton and Morozov, two great scientists who during many decades (! intensively considered problems of examination of chronology and history.

  16. Chronology of enstatite chondrites and ureilites

    International Nuclear Information System (INIS)

    This paper summarizes the chronological studies on enstatite chondrites and ureilites, both of which are special groups of meteorites with unknown origins. Two unequilibrated enstatite chondrites, Qingzhen and Yamato 6901 (E3), showed the highly disturbed Rb-Sr system, while their silicate fractions yielded the 2.1 Ga isochron. The thermally metamorphosed enstatite chondrite Khairpur (E6) showed the older Rb-Sr age of 4.50 Ga. The parent body of E3 chondrites experienced late thermal event at low temperature, which broke down alkali-bearing sulfides in E3. The observed Rb-Sr data are consistent with the mobilization of Rb from alkali-sulfide to silicate phases. Ureilites show highly depleted trace elements abundance which makes it difficult to determine the age of the formation. The U-Pb and Sm-Nd age determination of low-Ca ureilite Goalpara showed that the Pb and Nd isotopes are heavily contaminated with terrestrial components. The acid residues of high-Ca ureilite MET-78008 were free of contamination and defined the old U-Pb age of 4.563±0.006 Ga. The early formation of ureilites supports their formation through the collisional destruction of the parent body. Including the ureilite date, many evolved meteorites formed within the first 10 million years of the solar system history. Future studies on meteorite chronology with the purpose of understanding the early history of the solar system should focus on the fine time resolution through the precise U-Pb age determination or the relative age determination using the extinct nuclides with half lives less than 10 million years. (author)

  17. Jewish Holocaust Histories and the Work of Chronological Narratives

    Science.gov (United States)

    Silverstein, Jordana

    2012-01-01

    This article examines the ways that, in Holocaust education in Jewish schools in Melbourne and New York at the beginning of the 21st century, knowledge of the Holocaust is transferred to students in chronological form. It begins by asking: What work do chronological narratives do within the Holocaust historical narratives offered within Jewish…

  18. Time and Chronology: Conjoined Twins or Distant Cousins?

    Science.gov (United States)

    Blow, Frances; Lee, Peter; Shemilt, Denis

    2012-01-01

    Weaknesses in pupils' grasp of historical chronology are a commonplace in popular discussion of the state of history education. However, as Blow, Lee and Shemilt argue, although undoubtedly necessary and fundamental, mastery of chronological conventions is not sufficient: the difficulties that pupils experience when learning history are…

  19. Prospects for Chronological Studies of Martian Rocks and Soils

    Science.gov (United States)

    Nyquist, L. E.; Shih, C-Y.; Reese, Y. D.

    2008-01-01

    Chronological information about Martian processes comes from two sources: Crater-frequency studies and laboratory studies of Martian meteorites. Each has limitations that could be overcome by studies of returned Martian rocks and soils. Chronology of Martian volcanism: The currently accepted chronology of Martian volcanic surfaces relies on crater counts for different Martian stratigraphic units [1]. However, there is a large inherent uncertainty for intermediate ages near 2 Ga ago. The effect of differing preferences for Martian cratering chronologies [1] is shown in Fig. 1. Stoeffler and Ryder [2] summarized lunar chronology, upon which Martian cratering chronology is based. Fig. 2 shows a curve fit to their data, and compares to it a corresponding lunar curve from [3]. The radiometric ages of some lunar and Martian meteorites as well as the crater-count delimiters for Martian epochs [4] also are shown for comparison to the craterfrequency curves. Scaling the Stoeffler-Ryder curve by a Mars/Moon factor of 1.55 [5] places Martian shergottite ages into the Early Amazonian to late Hesperian epochs, whereas using the lunar curve of [3] and a Mars/Moon factor 1 consigns the shergottites to the Middle-to-Late Amazonian, a less probable result. The problem is worsened if a continually decreasing cratering rate since 3 Ga ago is accepted [6]. We prefer the adjusted St ffler-Ryder curve because it gives better agreement with the meteorite ages (Fig.

  20. Gamma spectrometry for chronology of recent sediments

    Energy Technology Data Exchange (ETDEWEB)

    Pittauerova, Daniela

    2013-12-17

    This thesis deals with several aspects of gamma spectrometric analysis of natural and artificial isotopes in sediments and their use as tracers for qualification and quantification of accumulation and mixing processes in different aquatic environments. Sediment cores from three distinct areas including terrigenous sediments deposited on the continental slope off NW Africa, deep sea sediments off Sumba Island and five stations from the Gulf of Eilat in the Red Sea area were measured and interpreted within this dissertation. The main concern in gamma spectrometry of voluminous environmental samples is a reliable efficiency calibration. This is specially relevant for the analysis of low energy gamma emitters (<100 keV). {sup 210}Pb, an important isotopic tracer to cover the period of the last century, is one of them. Within this work mathematical efficiency calibration was applied using a commercial software package. A series of validation tests was performed and evaluated for point and voluminous samples. When using {sup 210}Pb as a tracer it is necessary to determine its excess portion, which is not supported by ingrowth from the parent nuclide {sup 226}Ra. Its analysis is mostly performed via short lived daughter isotopes that follow after the intermediate gaseous member {sup 222}Rn. Preventing the escape of radon from the sample is a critical step before analysis due to a negative effect of supported {sup 210}Pb underestimation on the chronology, which was also documented in this thesis. Time series registering ingrowth of {sup 214}Pb and {sup 214}Bi towards radioactive equilibrium with {sup 226}Ra in different containers were evaluated for analyses of {sup 226}Ra. Direct analyses of {sup 226}Ra was compared to its detection via daughter products. A method for aligning parallel radionuclide depth profiles was described and applied successfully in two case studies from the continental slope off NW Africa and off Sumba Island, Indonesia. This is primarily important

  1. Gamma spectrometry for chronology of recent sediments

    International Nuclear Information System (INIS)

    This thesis deals with several aspects of gamma spectrometric analysis of natural and artificial isotopes in sediments and their use as tracers for qualification and quantification of accumulation and mixing processes in different aquatic environments. Sediment cores from three distinct areas including terrigenous sediments deposited on the continental slope off NW Africa, deep sea sediments off Sumba Island and five stations from the Gulf of Eilat in the Red Sea area were measured and interpreted within this dissertation. The main concern in gamma spectrometry of voluminous environmental samples is a reliable efficiency calibration. This is specially relevant for the analysis of low energy gamma emitters (<100 keV). 210Pb, an important isotopic tracer to cover the period of the last century, is one of them. Within this work mathematical efficiency calibration was applied using a commercial software package. A series of validation tests was performed and evaluated for point and voluminous samples. When using 210Pb as a tracer it is necessary to determine its excess portion, which is not supported by ingrowth from the parent nuclide 226Ra. Its analysis is mostly performed via short lived daughter isotopes that follow after the intermediate gaseous member 222Rn. Preventing the escape of radon from the sample is a critical step before analysis due to a negative effect of supported 210Pb underestimation on the chronology, which was also documented in this thesis. Time series registering ingrowth of 214Pb and 214Bi towards radioactive equilibrium with 226Ra in different containers were evaluated for analyses of 226Ra. Direct analyses of 226Ra was compared to its detection via daughter products. A method for aligning parallel radionuclide depth profiles was described and applied successfully in two case studies from the continental slope off NW Africa and off Sumba Island, Indonesia. This is primarily important when combined profiles obtained from short multicorer cores

  2. Chronological History of Federal Fleet Actions and Mandates (Brochure)

    Energy Technology Data Exchange (ETDEWEB)

    2011-04-01

    This chronological history of Federal fleet actions and mandates provides a year-by-year timeline of the acts, amendments, executive orders, and other regulations that affect Federal fleets. The fleet actions and mandates included in the timeline span from 1988 to 2009.

  3. Nurturing Children's Concepts of Time and Chronology through Literature

    Science.gov (United States)

    Harms, Jeanne McLain; Lettow, Lucille J.

    2007-01-01

    Time is an emerging concept during childhood. At first, children's concept of time is rather vague. Banks and Banks suggest that the goal for teaching time concepts and chronology in the elementary and middle school years should be to nurture students' ability to understand and interpret time concepts and comprehend how past and present events are…

  4. Quantifying yeast chronological life span by outgrowth of aged cells.

    Science.gov (United States)

    Murakami, Christopher; Kaeberlein, Matt

    2009-01-01

    The budding yeast Saccharomyces cerevisiae has proven to be an important model organism in the field of aging research. The replicative and chronological life spans are two established paradigms used to study aging in yeast. Replicative aging is defined as the number of daughter cells a single yeast mother cell produces before senescence; chronological aging is defined by the length of time cells can survive in a non-dividing, quiescence-like state. We have developed a high-throughput method for quantitative measurement of chronological life span. This method involves aging the cells in a defined medium under agitation and at constant temperature. At each age-point, a sub-population of cells is removed from the aging culture and inoculated into rich growth medium. A high-resolution growth curve is then obtained for this sub-population of aged cells using a Bioscreen C MBR machine. An algorithm is then applied to determine the relative proportion of viable cells in each sub-population based on the growth kinetics at each age-point. This method requires substantially less time and resources compared to other chronological lifespan assays while maintaining reproducibility and precision. The high-throughput nature of this assay should allow for large-scale genetic and chemical screens to identify novel longevity modifiers for further testing in more complex organisms. PMID:19421136

  5. A Survey of the Xia-Shang-Zhou Chronology Project

    Institute of Scientific and Technical Information of China (English)

    Xi Zezong

    2002-01-01

    @@ Ⅰ. Goals In connection with the history of science, the XiaShang-Zhou Chronology Project is one of the important projects of the National Key Science and Technology Research and Development Programme of the Ninth Five-Year Plan. It officially began in May 1996.After five years of effort by more than 200 scholars and experts from the Chinese Academy of Sciences,the Chinese Academy of Social Sciences, Peking University and other institutions, the project has attained its goal. The general goal of the project is to establish a chronological table for the three dynasties by means of combining the humanities and social sciences with the natural sciences. The concrete goals for different historical periods are:

  6. Energy history chronology from World War II to the present

    Energy Technology Data Exchange (ETDEWEB)

    Dean, P.C.

    1982-08-01

    This report provides a basic guide to the major Presidential, Legislative, Judicial, and Federal agency actions relating to energy policy, research, development, and regulation in recent years. The chronology is arranged synoptically, allowing users to reference easily the historical context in which each event occurred. Summaries of Presidential, Legislative, and Judicial actions relating to energy, rosters of federal energy officials, and a genealogy of federal energy agencies are also provided in separate appendices. The Energy History Chronology was prepared in conjunction with the History Division's series of pamphlets on the Institutional Origins of the Department of Energy. The series includes concise histories of the Department of Energy, the Energy Research and Development Administration, the Federal Energy Administration, and the Atomic Energy Commission. All significant events and achievements noted in the institutional history are also listed.

  7. Chronology protection in stationary three-dimensional spacetimes

    CERN Document Server

    Raeymaekers, Joris

    2011-01-01

    We study chronology protection in stationary, rotationally symmetric spacetimes in 2+1 dimensional gravity, focusing especially on the case of negative cosmological constant. We show that in such spacetimes closed timelike curves must either run all the way to the boundary or, alternatively, the matter stress tensor must violate the null energy condition in the bulk. We also show that the matter in the closed timelike curve region gives a negative contribution to the conformal weight from the point of view of the dual conformal field theory. We illustrate these properties in a class of examples involving rotating dust in anti-de Sitter space, and comment on the use of the AdS/CFT correspondence to study chronology protection.

  8. The use of AMS radiocarbon dating for Xia-Shang-Zhou chronology

    CERN Document Server

    Guo, Z Y; LiuKeXin; Lu Xiang Yang; Ma Hong Ji; Wu Xiao Hon; Yuan Si Xun

    2000-01-01

    The possibility and problems of using radiocarbon dating to historical chronology are discussed. The current situation of ancient Chinese chronology and the project of Xia-Shang-Zhou chronology are introduced. A chronological study requires the AMS radiocarbon dating with high precision, high reliability and high efficiency. The Peking University AMS facility (PKUAMS) has been upgraded and a series of quality control steps were adopted. To reduce the error of calendar age, wiggle matching with serial samples should be used. Some preliminary results of Xia-Shang-Zhou chronology are presented.

  9. REVIEW: South & East Asian Adult Education: Chronologies in Commonwealth Countries

    OpenAIRE

    SHARMA, Reviewed By Dr. Ramesh C.

    2002-01-01

    The major aim of this international research project was to record and analyze the chronological development of adult education in the country members of the commonwealth. It traces the developments in the area of adult education since early 1900s to the very latest as for 1999. This project was supported by the Commonwealth of Learning; the Ontario Institute for Studies in Education, University of Toronto; the Commonwealth Association for the Education and Training of Adults; and the United ...

  10. The Chronology of Third Molar Eruption in the Croatian Population

    OpenAIRE

    Brkić, Hrvoje; Vodanović, Marin; Dumančić, Jelena; Lovrić, Željka; Čuković-Bagić, Ivana; Petrovečki, Mladen

    2011-01-01

    Dental age estimation is common in orthodontics, paedodontics, paleodontology and forensic dentistry. The aim of this study was to assess chronological course of eruptive developmental phases of third molar and to establish parameters for the Croatian population. Sample of this study consisted of 1249 orthopantomograms of 530 (42.4%) male and 719 (57.6%) female subjects, aged 10 to 25 years. Eruptive phases were classified in 4 stages. No significant sex difference was found. Esta...

  11. Mars chronology: assessing techniques for quantifying surficial processes

    Science.gov (United States)

    Doran, Peter T.; Clifford, Stephen M.; Forman, Steven L.; Nyquist, Larry; Papanastassiou, Dimitri A.; Stewart, Brian W.; Sturchio, Neil C.; Swindle, Timothy D.; Cerling, Thure; Kargel, Jeff

    2004-01-01

    Currently, the absolute chronology of Martian rocks, deposits and events is based mainly on crater counting and remains highly imprecise with epoch boundary uncertainties in excess of 2 billion years. Answers to key questions concerning the comparative origin and evolution of Mars and Earth will not be forthcoming without a rigid Martian chronology, enabling the construction of a time scale comparable to Earth's. Priorities for exploration include calibration of the cratering rate, dating major volcanic and fluvial events and establishing chronology of the polar layered deposits. If extinct andor extant life is discovered, the chronology of the biosphere will be of paramount importance. Many radiometric and cosmogenic techniques applicable on Earth and the Moon will apply to Mars after certain baselines (e.g. composition of the atmosphere, trace species, chemical and physical characteristics of Martian dust) are established. The high radiation regime may pose a problem for dosimetry-based techniques (e.g. luminescence). The unique isotopic composition of nitrogen in the Martian atmosphere may permit a Mars-specific chronometer for tracing the time-evolution of the atmosphere and of lithic phases with trapped atmospheric gases. Other Mars-specific chronometers include measurement of gas fluxes and accumulation of platinum group elements (PGE) in the regolith. Putting collected samples into geologic context is deemed essential, as is using multiple techniques on multiple samples. If in situ measurements are restricted to a single technique it must be shown to give consistent results on multiple samples, but in all cases, using two or more techniques (e.g. on the same lander) will reduce error. While there is no question that returned samples will yield the best ages, in situ techniques have the potential to be flown on multiple missions providing a larger data set and broader context in which to place the more accurate dates.

  12. Asbestos: a chronology of its origins and health effects.

    OpenAIRE

    Huncharek, M

    1990-01-01

    The emotionalised subject of asbestos is treated in chronological terms: how the "magic mineral" known in ancient times in Europe and Asia became in the late nineteenth century an important industrial resource of particular interest to the navies of the world; and how its malign effects gradually became apparent during the present century. The media have made asbestos a notorious villain, but it still has properties and applications useful to society if they are properly controlled in the sam...

  13. Tanshinones extend chronological lifespan in budding yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Wu, Ziyun; Song, Lixia; Liu, Shao Quan; Huang, Dejian

    2014-10-01

    Natural products with anti-aging property have drawn great attention recently but examples of such compounds are exceedingly scarce. By applying a high-throughput assay based on yeast chronological lifespan measurement, we screened the anti-aging activity of 144 botanical materials and found that dried roots of Salvia miltiorrhiza Bunge have significant anti-aging activity. Tanshinones isolated from the plant including cryptotanshione, tanshinone I, and tanshinone IIa, are the active components. Among them, cryptotanshinone can greatly extend the budding yeast Saccharomyces cerevisiae chronological lifespan (up to 2.5 times) in a dose- and the-time-of-addition-dependent manner at nanomolar concentrations without disruption of cell growth. We demonstrate that cryptotanshinone prolong chronological lifespan via a nutrient-dependent regime, especially essential amino acid sensing, and three conserved protein kinases Tor1, Sch9, and Gcn2 are required for cryptotanshinone-induced lifespan extension. In addition, cryptotanshinone significantly increases the lifespan of SOD2-deleted mutants. Altogether, those data suggest that cryptotanshinone might be involved in the regulation of, Tor1, Sch9, Gcn2, and Sod2, these highly conserved longevity proteins modulated by nutrients from yeast to humans.

  14. Construction of reliable radiocarbon-based chronologies for speleothems

    Science.gov (United States)

    Lechleitner, Franziska; Fohlmeister, Jens; McIntyre, Cameron; Baldini, Lisa M.; Jamieson, Robert A.; Hercman, Helena; Gasiorowski, Michal; Pawlak, Jacek; Stefaniak, Krzysztof; Socha, Pawel; Eglinton, Timothy I.; Baldini, James U. L.

    2016-04-01

    Speleothems have become one of the most widely applied archives for paleoclimate research. One of their key advantages is their amenability for U-series dating, often producing excellent high precision chronologies. However, stalagmites with high detrital Th or very low U concentrations are problematic to date using U-series, and sometimes need to be discarded from further paleoclimate analysis. Radiocarbon chronologies could present an alternative for stalagmites that cannot be dated using U-series, if offsets from the "dead carbon fraction" (DCF) can be resolved. The DCF is a variable reservoir effect introduced by the addition of 14C-dead carbon from host rock dissolution and soil organic matter. We present a novel age modeling technique that provides accurate 14C-based chronologies for stalagmites. As this technique focuses on the long-term decay pattern of 14C, it is only applicable on stalagmites that show no secular variability in their 14C-depth profiles, but is independent of short-term DCF variations. In order to determine whether a stalagmite is suitable for this method without direct knowledge of long-term trends in the DCF, we highlight how other geochemical proxies (δ13C, Mg/Ca) can provide additional information on changes in karst hydrology, soil conditions, and climate that would affect DCF. We apply our model on a previously published U-Th dated stalagmite 14C dataset from Heshang Cave, China with excellent results, followed by a previously 'undateable' stalagmite from southern Poland.

  15. Critical review of a new volcanic eruption chronology

    Science.gov (United States)

    Neuhäuser, Dagmar L.; Neuhäuser, Ralph

    2016-04-01

    Sigl. et al. (2015, Nature) present historical evidence for 32 volcanic eruptions to evaluate their new polar ice core 10-Be chronology - 24 are dated within three years of sulfur layers in polar ice. Most of them can be interpreted as weather phenomena (Babylonia: disk of sun like moon, reported for only one day, e.g. extinction due to clouds), Chinese sunspot reports (pellet, black vapor, etc.), solar eclipses, normal ice-halos and coronae (ring, bow, etc.), one aurora (redness), red suns due to mist drops in wet fog or fire-smoke, etc. Volcanic dust may facilitate detections of sunspots and formation of Bishop's ring, but tend to inhibit ice-halos, which are otherwise often reported in chronicles. We are left with three reports possibly indicating volcanic eruptions, namely fulfilling genuine criteria for atmospheric disturbances due to volcanic dust, e.g. bluish or faint sun, orange sky, or fainting of stars for months (BCE 208, 44-42, and 32). Among the volcanic eruptions used to fix the chronology (CE 536, 626, 939, 1257), the reports cited for the 930s deal only with 1-2 days, at least one reports an eclipse. In the new chronology, there is a sulfur detection eight years after the Vesuvius eruption, but none in CE 79. It may appear surprising that, from BCE 500 to 1, all five northern sulfur peaks labeled in figure 2 in Sigl et al. are systematically later by 2-4 years than the (corresponding?) southern peaks, while all five southern peaks from CE 100 to 600 labeled in figure 2 are systematically later by 1-4 years than the (corresponding?) northern peaks. Furthermore, in most of their six strongest volcanic eruptions, temperatures decreased years before their sulfur dating - correlated with weak solar activity as seen in radiocarbon, so that volcanic climate forcing appears dubious here. Also, their 10-Be peaks at CE 775 and 994 are neither significant nor certain in dating.

  16. Chronology of Mercury's geological and geophysical evolution - the Vulcanoid hypothesis

    International Nuclear Information System (INIS)

    The possibility that constraints on Mercury's chronology can be relaxed through reference to a Mercury-specific bombarding population of planetesimals interior to its orbit, and therefore only occasionally encountering the planet at times of secular perturbations, is investigated. While such vulcanoids may have been a significant source of early cratering, those in the pertinent orbits are depleted by mutual collisions and can therefore only furnish a modest extension of the heavy bombardment period. A search is conducted for vulcanoids further within Mercury's orbit; evidence that Mercury's intercrater plains are of volcanic origin is discussed. 99 references

  17. A new chronology for the Moon and Mercury

    CERN Document Server

    Marchi, S; Cremonese, G; Massironi, M; Martellato, E

    2009-01-01

    In this paper we present a new method for dating the surface of the Moon, obtained by modeling the incoming flux of impactors and converting it into a size distribution of resulting craters. We compare the results from this model with the standard chronology for the Moon showing their similarities and discrepancies. In particular, we find indications of a non-constant impactor flux in the last 500 Myr and also discuss the implications of our findings for the Late Heavy Bombardment hypothesis. We also show the potential of our model for accurate dating of other inner Solar System bodies, by applying it to Mercury.

  18. Extension of Chronological Calculus for Dynamical Systems on Manifolds

    OpenAIRE

    Kipka, Robert J.; Ledyaev, Yuri S.

    2014-01-01

    We propose an extension of the Chronological Calculus, developed by Agrachev and Gamkrelidze for the case of $C^\\infty$-smooth dynamical systems on finite-dimensional $C^\\infty$-smooth manifolds, to the case of $C^m$-smooth dynamical systems and infinite-dimensional $C^m$-manifolds. Due to a relaxation in the underlying structure of the calculus, this extension provides a powerful computational tool without recourse to the theory of calculus in Fr\\'echet spaces required by the classical Chron...

  19. The problem of the neolithisation process chronology in Povolzhye

    Directory of Open Access Journals (Sweden)

    Aleksandr Vybornov

    2013-12-01

    Full Text Available The Lower and Middle Volga basin regions border the Caucasus and Central Asia in the South. These regions are important in the study of the neolithisation process in Europe and the chronology of Neolithic cultures is of great significance in this respect. New 14C dates of different organic materials from archaeological sites in these regions have been obtained in the last five years. According to these data, the beginning of neolithisation in North Caspian region can be dated to the beginning of the 5th millennium BC; but in the Povolzhye it happened at least a millennium earlier.

  20. Chronologic changes of free fat graft in rabbit using CT

    International Nuclear Information System (INIS)

    Free fat grafts are now used for preventing osteal readhesion, filling dead space, and protecting grafted nerves and vessels. However, it is reported that grafted fat tissue is unstable resulting in high risk of cicatrization and infection. We grafted free fat to a rabbit's back and observed the chronologic change using CT. Ten adult male Japanese white rabbits (3.5 kg) were used. In five rabbits, fat tissue was obtained from the back under general anaesthesia, and transplanted into the back about 50 mm posterior from the donor site. CT was taken in the fixed scan condition five times (preoperation, immediate postoperation, postoperative 1-month, 2-month, and 3-month). In the remaining five rabbits, only CT scan was taken three times as a control. It was observed that we compared preoperative fat volume with the postoperative volume using RealINTAGE. Grafted fat tissue decreased postoperatively at 1-month and completely disappeared at 3-months. We were able to prove that CT scan is effective to observe the chronologic change of grafted fat tissue. Techniques of tissue engineering are necessary for survival of grafted fat tissue. (author)

  1. Biological versus chronological ovarian age: implications for assisted reproductive technology

    Directory of Open Access Journals (Sweden)

    Tredway Donald

    2009-09-01

    Full Text Available Abstract Background Women have been able to delay childbearing since effective contraception became available in the 1960s. However, fertility decreases with increasing maternal age. A slow but steady decrease in fertility is observed in women aged between 30 and 35 years, which is followed by an accelerated decline among women aged over 35 years. A combination of delayed childbearing and reduced fecundity with increasing age has resulted in an increased number and proportion of women of greater than or equal to 35 years of age seeking assisted reproductive technology (ART treatment. Methods Literature searches supplemented with the authors' knowledge. Results Despite major advances in medical technology, there is currently no ART treatment strategy that can fully compensate for the natural decline in fertility with increasing female age. Although chronological age is the most important predictor of ovarian response to follicle-stimulating hormone, the rate of reproductive ageing and ovarian sensitivity to gonadotrophins varies considerably among individuals. Both environmental and genetic factors contribute to depletion of the ovarian oocyte pool and reduction in oocyte quality. Thus, biological and chronological ovarian age are not always equivalent. Furthermore, biological age is more important than chronological age in predicting the outcome of ART. As older patients present increasingly for ART treatment, it will become more important to critically assess prognosis, counsel appropriately and optimize treatment strategies. Several genetic markers and biomarkers (such as anti-Müllerian hormone and the antral follicle count are emerging that can identify women with accelerated biological ovarian ageing. Potential strategies for improving ovarian response include the use of luteinizing hormone (LH and growth hormone (GH. When endogenous LH levels are heavily suppressed by gonadotrophin-releasing hormone analogues, LH supplementation may help

  2. Stable, Renormalizable, Scalar Tachyonic Quantum Field Theory with Chronology Protection

    CERN Document Server

    Radzikowski, Marek J

    2008-01-01

    We use microlocal arguments to suggest that Lorentz symmetry breaking must occur in a reasonably behaved tachyonic quantum field theory that permits renormalizability. In view of this, we present a scalar tachyonic quantum field model with manifestly broken Lorentz symmetry and without exponentially growing/decaying modes. A notion of causality, in which anti-telephones are excluded, and which is viewed as a form of chronology protection, is obeyed. The field theory is constructed in a preferred tachyon frame in terms of commuting creation/annihilation operators. We calculate some sample (renormalized) operators in this preferred frame, argue that the Hadamard condition is satisfied, and discuss the PCT and spin-statistics theorems for this model.

  3. Ştefania Cristescu-Golopenţia's Chronology

    Directory of Open Access Journals (Sweden)

    SANDA GOLOPENŢIA

    2013-07-01

    Full Text Available The present Chronology brings together data from the personal archive of Şt.C.-G. with data accumulated during the editing of her published and posthumous work that Sanda Golopenţia undertook after 1989. The author specifically calls attention to the new data regarding Şt.C.-G.'s 1938 and 1939 regional research in Ţara Oltului (the Olt County, the research she conducted in 1945 and 1947 in the Gurghiu Valley, and the social inquiry on the daily lives of her students in the Industrial Colege "Protopopul Tudor Economul" from Bucharest (1942-1943. The bibliography of St.C.-G.'s sociological, pedagogical and literary works was updated.

  4. Origin and chronology of chondritic components: A review

    Science.gov (United States)

    Krot, A. N.; Amelin, Y.; Bland, P.; Ciesla, F. J.; Connelly, J.; Davis, A. M.; Huss, G. R.; Hutcheon, I. D.; Makide, K.; Nagashima, K.; Nyquist, L. E.; Russell, S. S.; Scott, E. R. D.; Thrane, K.; Yurimoto, H.; Yin, Q.-Z.

    2009-09-01

    Mineralogical observations, chemical and oxygen-isotope compositions, absolute 207Pb- 206Pb ages and short-lived isotope systematics ( 7Be- 7Li, 10Be- 10B, 26Al- 26Mg, 36Cl- 36S, 41Ca- 41K, 53Mn- 53Cr, 60Fe- 60Ni, 182Hf- 182W) of refractory inclusions [Ca,Al-rich inclusions (CAIs) and amoeboid olivine aggregates (AOAs)], chondrules and matrices from primitive (unmetamorphosed) chondrites are reviewed in an attempt to test (i) the x-wind model vs. the shock-wave model of the origin of chondritic components and (ii) irradiation vs. stellar origin of short-lived radionuclides. The data reviewed are consistent with an external, stellar origin for most short-lived radionuclides ( 7Be, 10Be, and 36Cl are important exceptions) and a shock-wave model for chondrule formation, and provide a sound basis for early Solar System chronology. They are inconsistent with the x-wind model for the origin of chondritic components and a local, irradiation origin of 26Al, 41Ca, and 53Mn. 10Be is heterogeneously distributed among CAIs, indicating its formation by local irradiation and precluding its use for the early solar system chronology. 41Ca- 41K, and 60Fe- 60Ni systematics are important for understanding the astrophysical setting of Solar System formation and origin of short-lived radionuclides, but so far have limited implications for the chronology of chondritic components. The chronological significance of oxygen-isotope compositions of chondritic components is limited. The following general picture of formation of chondritic components is inferred. CAIs and AOAs were the first solids formed in the solar nebula ˜4567-4568 Myr ago, possibly within a period of events in nebular region(s) with high ambient temperature (at or above condensation temperature of forsterite), either throughout the inner protoplanetary disk (1-4 AU) or in a localized region near the proto-Sun ( -10‰) and have ( 26Al/ 27Al) 0 similar to those in chondrules (events in regions with low ambient temperature

  5. Chronology and origin of VMS deposits in Xinjiang, NW CHINA

    Institute of Scientific and Technical Information of China (English)

    CHEN; Fuwen(陈富文); LI; Huaqin(李华芹); WANG; Denghong(王登红); XIE; Caifu(谢才富); LU; Yuanfa(路远发)

    2002-01-01

    VMS deposits in Xinjiang, NW China are widespread in the Altay, Tianshan and West Kunlun orogenic belt, mainly formed during the Proterozoic rifting and Phanerozoic post-orogenic extension and are related to the bimodal volcanism. The VMS deposits are middle and small in scale. According to assemblages of metallogenetic elements, they can be divided into four types (Cu-Zn, Cu-S, Pb-Zn-Cu and Pb-Zn types) with the Cu-Zn and Pb-Zn types being the most important ones. Research of isotopic chronology shows that the VMS deposits in Xinjiang were formed during the Proterozoic, Ordovician, Deovonian, Carboniferous and Permian periods and usually underwent multi-stage mineralization, especially the large-sized deposits usually have post- volcanic superimposed mineralization by tectonomagmatic or metamorphic hydrothermal metallogenic fluids.

  6. Frost-ring chronologies as dendroclimatic proxies of boreal environments

    Science.gov (United States)

    Payette, Serge; Delwaide, Ann; Simard, Martin

    2010-01-01

    Frost rings are formed in tree stems when growing-season frosts affect immature wood cells, producing collapsed cells within annual tree rings. Open boreal forests are most susceptible to record growing-season frost because they lack the greenhouse effect commonly observed in closed forests. Here we present a novel method to construct regional frost-ring chronologies in lichen-black spruce woodlands of the boreal forest zone. Because the ability of trees to form frost rings depends on several factors (including bark thickness and ring width), we used two models to produce a Frost Composite Index based on a frost susceptibility window of cambial age growing-season frost activity may be used as dendroclimatic proxies of climate variability and may give insights into future risks of frost damage in a warming climate.

  7. Holographic Protection of Chronology in Universes of the Godel Type

    CERN Document Server

    Boyda, E; Horava, P; Varadarajan, U; Boyda, Edward; Ganguli, Surya; Horava, Petr; Varadarajan, Uday

    2003-01-01

    We analyze the structure of supersymmetric Godel-like cosmological solutions of string theory. Just as the original four-dimensional Godel universe, these solutions represent rotating, topologically trivial cosmologies with a homogeneous metric and closed timelike curves. First we focus on "phenomenological" aspects of holography, and identify the preferred holographic screens associated with inertial comoving observers in Godel universes. We find that holography can serve as a chronology protection agency: The closed timelike curves are either hidden behind the holographic screen, or broken by it into causal pieces. In fact, holography in Godel universes has many features in common with de Sitter space, suggesting that Godel universes could represent a supersymmetric laboratory for addressing the conceptual puzzles of de Sitter holography. Then we initiate the investigation of "microscopic" aspects of holography of Godel universes in string theory. We show that Godel universes are T-dual to pp-waves, and use...

  8. Statehood Day or Candlemas Day: Ideology vs. Chronology

    Directory of Open Access Journals (Sweden)

    Srđan Milošević

    2016-03-01

    Full Text Available The paper deals with the ideological and chronological issues concerning Statehood day, which is celebrated on the 15th and 16th of February in Serbia. The focus will be on the connection which is being established between the state holiday of Statehood day and Candlemas Day which is a church holiday. The paper will further deal with the problems with dating the two key events – the start of the First Serbian Uprising in 1804 and the adoption of the first Serbian Constitution in 1835 – which, according to the Serbian law on national and other holidays, form the basis for the celebrating of Statehood day. The paper will prove that it wasn’t necessary for the legislators to insist on establishing a connection between the aforementioned events and the date of the church holiday neither in the 19th nor in the 21st century. The author will also point out the significant errors in chronology: it is falsely claimed that the anniversaries of both these events coincide with Candlemas Day (in 1804 and 1835, respectively, and that it is hence unwarranted to claim that they coincide with Candlemas Day in the 21st century. It will be shown that the reason for these errors lies in the incorrect calculation and translation of dates from the Julian into the Gregorian calendar, as well as that the contemporary insistence on the connection between Statehood day and Candlemas Day is ideologically conditioned and that it is a consequence of the desecularization of Serbian society.

  9. Environmental factors influence lesser scaup migration chronology and population monitoring

    Science.gov (United States)

    Finger, Taylor A.; Afton, Alan D.; Schummer, Michael L.; Petrie, Scott A.; Badzinski, Shannon S.; Johnson, Michael A.; Szymanski, Michael L.; Jacobs, Kevin J.; Olsen, Glenn H.; Mitchell, Mark

    2016-01-01

    Identifying environmental metrics specific to lesser scaup (Aythya affinis; scaup) spring migration chronology may help inform development of conservation, management and population monitoring. Our objective was to determine how environmental conditions influence spring migration of lesser scaup to assess the effectiveness of the Waterfowl Breeding Population and Habitat Survey in accurately estimating scaup populations. We first compared peak timing of mallard (Anas platyrhynchos) and scaup migration from weekly ground surveys in North Dakota, USA because the Waterfowl Breeding Population and Habitat Survey is designed to capture annual mallard migration. As predicted, we detected that peak timing of scaup and mallard migrations differed in 25 of 36 years investigated (1980–2010). We marked scaup with satellite transmitters (n = 78; 7,403 locations) at Long Point, Lake Erie, Ontario, Canada; Pool 19 of the Mississippi River, Iowa and Illinois, USA; and Presque Isle Bay, Lake Erie, Pennsylvania, USA. We tested the assumption that our marked scaup were representative of the continental population using the traditional survey area by comparing timing of migration of marked birds and scaup counted in the North Dakota Game and Fish Department survey. We detected a strong positive correlation between marked scaup and the survey data, which indicated that marked scaup were representative of the population. We subsequently used our validated sample of marked scaup to investigate the effects of annual variation in temperature, precipitation, and ice cover on spring migration chronology in the traditional and eastern survey areas of the Waterfowl Breeding Population and Habitat Survey, 2005–2010. We evaluated competing environmental models to explain variation in timing and rate of scaup migration at large-scale and local levels. Spring migration of scaup occurred earlier and faster during springs with warmer temperatures and greater precipitation, variables known

  10. Relationships between Chronological Age, Developmental Age, and Standardized Achievement Tests in Kindergarten.

    Science.gov (United States)

    Freberg, Laura

    1991-01-01

    Evaluated chronological age and results of Gesell School Readiness Test as predictors of kindergarten performance as measured by Stanford Achievement Test. Results from 284 kindergarten children indicated that both chronological and developmental age provided good predictors of Stanford Achievement Test performance in kindergarten. Findings have…

  11. TELL SABI ABYAD, SYRIA : RADIOCARBON CHRONOLOGY, CULTURAL CHANGE, AND THE 8.2 KA EVENT

    NARCIS (Netherlands)

    van der Plicht, J.; Akkermans, P. M. M. G.; Nieuwenhuyse, O.; Kaneda, A.; Russell, A.

    2011-01-01

    At Tell Sabi Abyad, Syria, we obtained a robust chronology for the 7th to early 6th millennium BC, the Late Neolithic. The chronology was obtained using a large set of radiocarbon dates, analyzed by Bayesian statistics. Cultural changes observed at similar to 6200 BC are coeval with the 8.2 ka clima

  12. An 854-Year Tree-Ring Chronology of Scots Pine for South-West Finland

    Directory of Open Access Journals (Sweden)

    Helama Samuli

    2014-04-01

    Full Text Available A near-millennial tree-ring chronology (AD 1147-2000 is presented for south-west Finland and analyzed using dendroclimatic methods. This is a composite chronology comprising samples both from standing pine trees (Pinus sylvestris L. and subfossil trunks as recovered from the lake sediments, with a total sample size of 189 tree-ring sample series. The series were dendrochronologically cross-dated to exact calendar years to portray variability in tree-ring widths on inter-annual and longer scales. Al though the studied chronology correlates statistically significantly with other long tree-ring width chronologies from Finland over their common period (AD 1520-1993, the south-west chronology did not exhibit similarly strong mid-summer temperature or spring/early-summer precipitation signals in comparison to published chronologies. On the other hand, the south-west chronology showed highest correlations to the North Atlantic Oscillation indices in winter/spring months, this association following a dendroclimatic feature common to pine chronologies over the region and adjacent areas. Paleoclimatic comparison showed that tree-rings had varied similarly to central European spring temperatures. It is postulated that the collected and dated tree-ring material could be studied for wood surface reflectance (blue channel light intensity and stable isotopes, which both have recently shown to correlate notably well with summer temperatures.

  13. Characterising the Welsh Roundhouse: chronology, inhabitation and landscape

    Directory of Open Access Journals (Sweden)

    Eleanor Ghey

    2007-11-01

    Full Text Available The article stems from a one-year project funded by the University of Wales Board of Celtic Studies to collect and analyse all the evidence for excavated prehistoric and early historic roundhouses in Wales. The resulting dataset will serve as a resource for researchers and, through the analysis provided in this article, provide an important counterpoint to similar studies from elsewhere in Britain. The methodology of the project is presented, and the limitations of the data are discussed in detail. The principal difficulties were associated with dating the building and duration of use of individual structures, and the bias created by a few sites with large numbers of excavated structures. The analysis and interpretation of the data is presented in three sections: chronology, inhabitation and landscape, and historical overview. The emphasis on recently excavated sites with good chronological control has enabled a more confident reconstruction of the history of roundhouse occupation in Wales. This has shown that while the architectural form has relatively early origins with numbers beginning to grow after 1500 BC, it is primarily a feature of first millennium BC and early first millennium AD landscapes. During the first millennium BC, timber- and stone-built settlements are common, initially as enclosed sites, and later, by the Roman period, as both open and enclosed settlements. This is contrary to the situation in many other parts of Britain, where roundhouses and frequently field systems are dated to at least the mid-second millennium BC onwards. There were strong regional differences between regions at this time, with for instance the predominance of stone- and clay-built sites in north-west Wales and the absence of Roman period roundhouses in the north-east. The dataset derived from the project will remain as an important resource with which to research these regional differences in greater detail and to examine the implications of new

  14. Chronology of petroleum geophysics; Sekiyu butsuri tansa nenpyo

    Energy Technology Data Exchange (ETDEWEB)

    Kametani, T.

    1996-10-01

    A table, chronology of petroleum geophysics in overseas and in Japan, has been prepared for the convenience of checking events, which are thought to be important as notable affairs in application, success, and technical innovation. In overseas, successes in the 1920s were remarkable, when the US modern geophysical exploration made a start. Successes in determining the position of exploratory drilling by means of the gravity torsion balance, fan shooting seismic refraction method, and seismic reflection method occurred one after another. The USA has kept its situation stably as the number one by the seismic reflection method occurred most lately, and its life has been further elongated by adopting digital techniques. The CDP technique which became to be used simultaneously, and the seismic sources without using explosives, such as vibro-seismic source and air gun, extended the success of digital techniques drastically. In the future, the progress of 3-D exploration technology is expected. In Japan, about 18 years lag in the seismic reflection method is observed when compared with the USA. Japan has provided leading techniques in the shallow layer seismic reflection method and S-wave exploration. 40 refs., 1 tab.

  15. Holographic Protection of Chronology in Universes of the Godel Type

    Energy Technology Data Exchange (ETDEWEB)

    Boyda, Edward; Ganguli, Surya; Horava, Petr; Varadarajan, Uday

    2002-12-07

    We analyze the structure of supersymmetric Godel-like cosmological solutions of string theory. Just as the original four-dimensional Godel universe, these solutions represent rotating, topologically trivial cosmologies with a homogeneous metric and closed timelike curves. First we focus on"phenomenological" aspects of holography, and identify the preferred holographic screens associated with inertial comoving observers in Godel universes. We find that holography can serve as a chronology protection agency: The closed timelike curves are either hidden behind the holographic screen, or broken by it into causal pieces. In fact, holography in Godel universes has many features in common with de Sitter space, suggesting that Godel universes could represent a supersymmetric laboratory for addressing the conceptual puzzles of de Sitter holography. Then we initiate the investigation of"microscopic" aspects of holography of Godel universes in string theory. We show that Godel universes are T-dual to pp-waves, and use this fact to generate new Godel-like solutions of string and M-theory by T-dualizing known supersymmetric pp-wave solutions.

  16. On the Chronological Structure of the Solutrean in Southern Iberia.

    Science.gov (United States)

    Cascalheira, João; Bicho, Nuno

    2015-01-01

    The Solutrean techno-complex has gained particular significance over time for representing a clear demographic and techno-typological deviation from the developments occurred during the course of the Upper Paleolithic in Western Europe. Some of Solutrean's most relevant features are the diversity and techno-typological characteristics of the lithic armatures. These have been recurrently used as pivotal elements in numerous Solutrean-related debates, including the chronological organization of the techno-complex across Iberia and Southwestern France. In Southern Iberia, patterns of presence and/or absence of specific point types in stratified sequences tend to validate the classical ordering of the techno-complex into Lower, Middle and Upper phases, although some evidence, namely radiocarbon determinations, have not always been corroborative. Here we present the first comprehensive analysis of the currently available radiocarbon data for the Solutrean in Southern Iberia. We use a Bayesian statistical approach from 13 stratified sequences to compare the duration, and the start and end moments of each classic Solutrean phase across sites. We conclude that, based on the current data, the traditional organization of the Solutrean cannot be unquestionably confirmed for Southern Iberia, calling into doubt the status of the classically-defined type-fossils as precise temporal markers.

  17. On the Chronological Structure of the Solutrean in Southern Iberia.

    Directory of Open Access Journals (Sweden)

    João Cascalheira

    Full Text Available The Solutrean techno-complex has gained particular significance over time for representing a clear demographic and techno-typological deviation from the developments occurred during the course of the Upper Paleolithic in Western Europe. Some of Solutrean's most relevant features are the diversity and techno-typological characteristics of the lithic armatures. These have been recurrently used as pivotal elements in numerous Solutrean-related debates, including the chronological organization of the techno-complex across Iberia and Southwestern France. In Southern Iberia, patterns of presence and/or absence of specific point types in stratified sequences tend to validate the classical ordering of the techno-complex into Lower, Middle and Upper phases, although some evidence, namely radiocarbon determinations, have not always been corroborative. Here we present the first comprehensive analysis of the currently available radiocarbon data for the Solutrean in Southern Iberia. We use a Bayesian statistical approach from 13 stratified sequences to compare the duration, and the start and end moments of each classic Solutrean phase across sites. We conclude that, based on the current data, the traditional organization of the Solutrean cannot be unquestionably confirmed for Southern Iberia, calling into doubt the status of the classically-defined type-fossils as precise temporal markers.

  18. Chronological aging in conidia of pathogenic Aspergillus: Comparison between species.

    Science.gov (United States)

    Oliveira, Manuela; Pereira, Clara; Bessa, Cláudia; Araujo, Ricardo; Saraiva, Lucília

    2015-11-01

    Aspergillus fumigatus, Aspergillus flavus, Aspergillus terreus and Aspergillus niger are common airborne fungi, and the most frequent causative agents of human fungal infections. However, the resistance and lifetime persistence of these fungi in the atmosphere, and the mechanism of aging of Aspergillus conidia are unknown.With this work, we intended to study the processes underlying conidial aging of these four relevant and pathogenic Aspergillus species. Chronological aging was therefore evaluated in A. fumigatus, A. flavus, A. terreus and A. niger conidia exposed to environmental and human body temperatures. The results showed that the aging process in Aspergillus conidia involves apoptosis,with metacaspase activation, DNA fragmentation, and reactive oxygen species production, associated with secondary necrosis. Distinct results were observed for the selected pathogenic species. At environmental conditions, A. niger was the species with the highest resistance to aging, indicating a higher adaption to environmental conditions, whereas A. flavus followed by A. terreus were the most sensitive species. At higher temperatures (37 °C), A. fumigatus presented the longest lifespan, in accordance with its good adaptation to the human body temperature. Altogether,with this work new insights regarding conidia aging are provided, which may be useful when designing treatments for aspergillosis.

  19. Molecular biomarkers for chronological age in animal ecology.

    Science.gov (United States)

    Jarman, Simon N; Polanowski, Andrea M; Faux, Cassandra E; Robbins, Jooke; De Paoli-Iseppi, Ricardo; Bravington, Mark; Deagle, Bruce E

    2015-10-01

    The chronological age of an individual animal predicts many of its biological characteristics, and these in turn influence population-level ecological processes. Animal age information can therefore be valuable in ecological research, but many species have no external features that allow age to be reliably determined. Molecular age biomarkers provide a potential solution to this problem. Research in this area of molecular ecology has so far focused on a limited range of age biomarkers. The most commonly tested molecular age biomarker is change in average telomere length, which predicts age well in a small number of species and tissues, but performs poorly in many other situations. Epigenetic regulation of gene expression has recently been shown to cause age-related modifications to DNA and to cause changes in abundance of several RNA types throughout animal lifespans. Age biomarkers based on these epigenetic changes, and other new DNA-based assays, have already been applied to model organisms, humans and a limited number of wild animals. There is clear potential to apply these marker types more widely in ecological studies. For many species, these new approaches will produce age estimates where this was previously impractical. They will also enable age information to be gathered in cross-sectional studies and expand the range of demographic characteristics that can be quantified with molecular methods. We describe the range of molecular age biomarkers that have been investigated to date and suggest approaches for developing the newer marker types as age assays in nonmodel animal species.

  20. The chronology of third molar mineralization by digital orthopantomography.

    Science.gov (United States)

    Maled, Venkatesh; Vishwanath, S B

    2016-10-01

    The present study was designed to determine the chronology of third molar mineralization to establish Indian reference data and to observe the advantages of digital orthopantomography. Therefore, a cross-sectional study was undertaken by evaluating 167 digital orthopantomographs in order to assess the mineralization status of the mandibular third molar of Caucasian individuals (85 males and 82 females) between the age of 14 and 24. The evaluation was carried out using the 8-stage developmental scheme of Demirjian et al (1973). The range, mean age, standard deviation and Student t-test are presented for each stage of mineralization in all four quadrants. Statistically significant differences between males and females were not found for all four third molars. All the individuals in this study with mature third molar were at least 18 years of age. For medicolegal purposes, the likelihood of whether an Indian is older than 18 years or not was determined. The advantage of digital orthopantomography in the interpretation of the tooth mineralization over the traditional method was acknowledged. PMID:27485643

  1. The chronology of third molar mineralization by digital orthopantomography.

    Science.gov (United States)

    Maled, Venkatesh; Vishwanath, S B

    2016-10-01

    The present study was designed to determine the chronology of third molar mineralization to establish Indian reference data and to observe the advantages of digital orthopantomography. Therefore, a cross-sectional study was undertaken by evaluating 167 digital orthopantomographs in order to assess the mineralization status of the mandibular third molar of Caucasian individuals (85 males and 82 females) between the age of 14 and 24. The evaluation was carried out using the 8-stage developmental scheme of Demirjian et al (1973). The range, mean age, standard deviation and Student t-test are presented for each stage of mineralization in all four quadrants. Statistically significant differences between males and females were not found for all four third molars. All the individuals in this study with mature third molar were at least 18 years of age. For medicolegal purposes, the likelihood of whether an Indian is older than 18 years or not was determined. The advantage of digital orthopantomography in the interpretation of the tooth mineralization over the traditional method was acknowledged.

  2. Growth Culture Conditions and Nutrient Signaling Modulating Yeast Chronological Longevity

    Directory of Open Access Journals (Sweden)

    Júlia Santos

    2012-01-01

    Full Text Available The manipulation of nutrient-signaling pathways in yeast has uncovered the impact of environmental growth conditions in longevity. Studies using calorie restriction show that reducing glucose concentration of the culture media is sufficient to increase replicative and chronological lifespan (CLS. Other components of the culture media and factors such as the products of fermentation have also been implicated in the regulation of CLS. Acidification of the culture media mainly due to acetic acid and other organic acids production negatively impacts CLS. Ethanol is another fermentative metabolite capable of inducing CLS reduction in aged cells by yet unknown mechanisms. Recently, ammonium was reported to induce cell death associated with shortening of CLS. This effect is correlated to the concentration of NH4+ added to the culture medium and is particularly evident in cells starved for auxotrophy-complementing amino acids. Studies on the nutrient-signaling pathways regulating yeast aging had a significant impact on aging-related research, providing key insights into mechanisms that modulate aging and establishing the yeast as a powerful system to extend knowledge on longevity regulation in multicellular organisms.

  3. Nutrient Limitation of Microbial Mediated Decomposition and Arctic Soil Chronology

    Science.gov (United States)

    Melle, C. J.; Darrouzet-Nardi, A.; Wallenstein, M. D.

    2012-12-01

    Soils of northern permafrost regions currently contain twice as much carbon as the entire Earth's atmosphere. Traditionally, environmental constraints have limited microbial activity resulting in restricted decomposition of soil organic matter in these systems and accumulation of massive amounts of soil organic carbon (SOC), however climate change is reducing the constraints of decomposition in arctic permafrost regions. Carbon cycling in nutrient poor, arctic ecosystems is tightly coupled to other biogeochemical cycles. Several studies have suggested strong nitrogen limitations of primary productivity and potentially warm-season microbial activity in these nutrient deficient soils. Nitrogen is required for microbial extracellular enzyme production which drives the decomposition of soil organic matter (SOM). Nitrogen limited arctic soils may also experience limitation via labile carbon availability despite the SOM rich environment due to low extracellular enzyme production. Few studies have directly addressed nutrient induced microbial limitation in SOC rich arctic tundra soils, and even less is known about the potential for nutrient co-limitation. Additionally, through the process of becoming deglaciated, sites within close proximity to one another may have experienced drastic differences in their effective soil ages due to the varied length of their active histories. Many soil properties and nutrient deficiencies are directly related to soil age, however this chronology has not previously been a focus of research on nutrient limitation of arctic soil microbial activity. Understanding of nutrient limitations, as well as potential co-limitation, on arctic soil microbial activity has important implications for carbon cycling and the ultimate fate of the current arctic SOC reservoir. Analyses of nutrient limitation on soils of a single site are not adequate for fully understanding the controls on soil microbial activity across a vast land mass with large variation in

  4. Impact of tumor chronology and tumor biology on lymph node metastasis in breast cancer

    OpenAIRE

    Smeets, Ann; Ryckx, Andries; Belmans, Ann; Wildiers, Hans; Neven, Patrick; Floris, Giuseppe; Schöffski, Patrick; Christiaens, Marie-Rose

    2013-01-01

    Synopsis The significance of nodal metastasis in breast cancer is under discussion. We investigated the impact of variables of tumor chronology and tumor biology on the presence of lymph node metastases. Purpose Lymph node involvement is the main prognostic factor in breast cancer. However, it is under discussion whether nodal metastasis in breast cancer only reflects the chronological age of the tumor or whether it is also a marker of tumor biology. The goal of our study was to investigate t...

  5. Evidence for last interglacial chronology and environmental change from Southern Europe

    OpenAIRE

    Achim Brauer; Allen, J.R.M.; Jens Mingram; Peter Dulski; Sabine Wulf; Huntley, B.

    2007-01-01

    Establishing phase relationships between earth-system components during periods of rapid global change is vital to understanding the underlying processes. It requires records of each component with independent and accurate chronologies. Until now, no continental record extending from the present to the penultimate glacial had such a chronology to our knowledge. Here, we present such a record from the annually laminated sediments of Lago Grande di Monticchio, southern Italy. Using this record ...

  6. A 60 000 year Greenland stratigraphic ice core chronology

    Directory of Open Access Journals (Sweden)

    K. K. Andersen

    2007-11-01

    Full Text Available The Greenland Ice Core Chronology 2005 (GICC05 is a time scale based on annual layer counting of high-resolution records from Greenland ice cores. Whereas the Holocene part of the time scale is based on various records from the DYE-3, the GRIP, and the NorthGRIP ice cores, the glacial part is solely based on NorthGRIP records. Here we present an 18 kyr extension of the time scale such that GICC05 continuously covers the past 60 kyr. The new section of the time scale places the onset of Greenland Interstadial 12 (GI-12 at 46.9±1.0 kyr b2k (before year AD 2000, the North Atlantic Ash Zone 2 layer in GI-15 at 55.4±1.2 kyr b2k, and the onset of GI-17 at 59.4±1.3 kyr b2k. The error estimates are derived from the accumulated number of uncertain annual layers and can be regarded as 1σ uncertainties. In the 40–60 kyr interval the new time scale has a discrepancy with the Meese-Sowers GISP2 time scale of up to 2.4 kyr, whereas GICC05 compares well to the dating of the Hulu Cave record with absolute age differences of less than 800 years throughout the 60 kyr period. The new time scale is generally in close agreement with other independently dated records and reference horizons, such as the Laschamp geomagnetic excursion and the Kleegruben speleothem record from the Austrian Alps, suggesting high accuracy of both event durations and absolute age estimates.

  7. A 60 000 year Greenland stratigraphic ice core chronology

    Directory of Open Access Journals (Sweden)

    A. Svensson

    2008-03-01

    Full Text Available The Greenland Ice Core Chronology 2005 (GICC05 is a time scale based on annual layer counting of high-resolution records from Greenland ice cores. Whereas the Holocene part of the time scale is based on various records from the DYE-3, the GRIP, and the NorthGRIP ice cores, the glacial part is solely based on NorthGRIP records. Here we present an 18 ka extension of the time scale such that GICC05 continuously covers the past 60 ka. The new section of the time scale places the onset of Greenland Interstadial 12 (GI-12 at 46.9±1.0 ka b2k (before year AD 2000, the North Atlantic Ash Zone II layer in GI-15 at 55.4±1.2 ka b2k, and the onset of GI-17 at 59.4±1.3 ka b2k. The error estimates are derived from the accumulated number of uncertain annual layers. In the 40–60 ka interval, the new time scale has a discrepancy with the Meese-Sowers GISP2 time scale of up to 2.4 ka. Assuming that the Greenland climatic events are synchronous with those seen in the Chinese Hulu Cave speleothem record, GICC05 compares well to the time scale of that record with absolute age differences of less than 800 years throughout the 60 ka period. The new time scale is generally in close agreement with other independently dated records and reference horizons, such as the Laschamp geomagnetic excursion, the French Villars Cave and the Austrian Kleegruben Cave speleothem records, suggesting high accuracy of both event durations and absolute age estimates.

  8. Chronological development avenues in biotechnology across the world

    Directory of Open Access Journals (Sweden)

    Prashant Y Mali

    2011-01-01

    Full Text Available Biotechnology is expected to be a great technological revolution followed by information technology. It is an application of scientific and engineering principles to the processing of material by biological agents to provide better goods and services to mankind. Commercially its techniques are applied long back in 6 th century in the art of brewing, wine making and baking. It has progressed there after crossing different land marks. Modern biotechnology has developed significantly in the late 19 th century with groundbreaking discoveries applicable in medicine, food, agriculture, chemistry, environmental protection and many more industries. It is widely used in the development of high-yielding, disease-resistant, better quality varieties by applying tissue culture and recombinant DNA techniques. It has wide application in animal breeding using techniques such as artificial insemination, in vitro fertilization and embryo transfer. Specific enzymes used in laundry, fuel and leather industries for better quality, economically feasible and environmental friendly production. Biotechnology in healthcare system uses body′s own tools and weapons to fight against diseases, manufacturing of targeted therapeutic proteins, gene therapy and so on. Novel approaches such as proteomics and structural biology are contributing to understanding the chemistry of life and diseases. Malfunctioning gene replaced with correctly functioning gene by using gene therapy. Tissue engineering has opened up the use of in vitro developed tissue or organ in repairing wounded tissue and system biology which is a computer-based approach to understand cell functions. Although every new discovery related to biology and its implications is significant and has taken the technology ahead. This includes applications, commercialization, controversies, media exposure and so on. Hence, we have enlisted some of the chronological development avenues in biotechnology across the world.

  9. Chronological Records of Li Anzhai and Yu Shiyu

    Institute of Scientific and Technical Information of China (English)

    WANG Hongliang

    2013-01-01

    In the history of Chinese ethnolo-gy, Li Anzhai and Yu Shiyu were not only life partners, but also an important academic married couple, especially in Tibetology.Li Anzhai was not only a representative in frontier research in China , but also a core figure in the West China school of Anthropology .He also has an important position in the history of modern academics . Yu Shiyu had an extremely rich talent for languages , and was good at sorting out bibliographies .Moreo-ver, she was interested in field investigation , which laid a solid foundation for her research on Tibetology .She also provided important support for Li Anzhai’ s fieldwork in Tibetan areas.The cou-ple ’ s academic life blended with each other , and they could be regarded as “two birds with the same destination” ( tianya tongming niao) . The life of this couple can help us understand that their life was both manifested and hidden from view by the times, and their academic life was both created and destroyed by the times .With regard to their academic position and social impact , it was a pity that their academic research did not meet the expectation of academic circles . Within various works related to the review of the history of the dis-ciplines, the couple was always included , in spite of the fact that the introductions to them were al-ways very simple .Although they are mentioned in some sporadic works , most of these works are only introductory articles or book reviews . Up until now, no one has systematically researched their life and academic thought .Hence, the author, by combing through various documents and archives , gives a chronological record of Li Anzhai ’ s and Yu Shiyu ’ s life story and academic achievements in order to provide basic historical data for academ-ic circles to carry out further research on the histo-ry of the discipline .

  10. Chronology of Awareness About US National Park External Threats

    Science.gov (United States)

    Shafer, Craig L.

    2012-12-01

    The objective of this paper is to raise understanding of the history of protected area external threat awareness in the United States and at World Protected Area Congresses. The earliest concerns about external threats to US national parks began in the late nineteenth century: a potential railroad transgression of Yellowstone National Park in the 1880s. During the early and mid 1930s, George Wright and colleagues focused on outside boundary concerns like of hunting and trapping of furbearers, grazing, logging, disease and hybridization between species. In the 1960s, a worldwide recognition began about the role of outside habitat fragmentation/isolation on nature reserves and human generated stressors crossing their boundaries. The State of the Park Report 1980 added a plethora of threats: oil/gas and geothermal exploration and development, hydropower and reclamation projects, urban encroachment, roads, resorts, and recreational facilities. The early 1980s ushered in political interference with NPS threats abatement efforts as well as Congressional legislative initiatives to support the abatement challenges of the agency. By 1987, the Government Accounting Office issued its first report on National Park Service (NPS) progress in dealing with external threats. Climate change impacts on parks, especially in terms of animals adjusting their temperature and moisture requirements by latitude and altitude, surfaced in the technical literature by the mid-1980s. By 1992, the world parks community stressed the need to integrate protected areas into the surrounding landscape and human community. The importance of the matrix has gradually gained appreciation in the scientific community. This chronology represents one example of national park and protected areas' institutional history contributing to the breath of modern conservation science.

  11. On the Assimilation of Tree-Ring-Width Chronologies

    Science.gov (United States)

    Acevedo, Walter; Reich, Sebastian; Cubasch, Ulrich

    2015-04-01

    Data assimilation (DA) of climate proxy records is currently acknowledged as a promising approach to the paleoclimate reconstruction problem, with the potential to bring physical consistency to reconstructed fields. Previous paleo-DA studies have typically assumed a linear relationship between climate forcing and the resulting proxy data, whereas there exist growing evidence of complex, potentially non-linear, proxy formation processes. Accordingly, it appears natural to simulate the proxy response to climate in a more realistic fashion, by way of proxy-specific forward models. Following this train of thought, we investigate the assimilation of the most traditional climate proxy type, Tree-Ring-Width (TRW) chronologies, using the process-based tree-ring growth forward model Vaganov-Shashkin-Lite (VSL) and ensemble Kalman filter (EnKF) techniques. Used as observation operator, VSL's formulation implies three compounding, challenging features: (i) time averaging, (ii) "switching recording" of 2 variables and (iii) bounded response windows leading to "thresholded response". DA experiments involving VSL-based pseudo-TRW observations are performed first for a chaotic 2-scale dynamical system, used as a cartoon of the atmosphere-land system, and then for an atmospheric general circulation model of intermediate complexity. Our results reveal that VSL's nonlinearities may considerable deteriorate the performance of EnKF for Time-Averaged (TA) estimation, as compared to the utilization of a TA linear observation operator. Moreover, we show that this assimilation skill loss can be considerably reduced by embedding VSL's formulation into fuzzy logic theory, which fosters new interpretations of tree-ring growth limitation processes.

  12. Isotope chronological trace of granite gravel in Hefei Basin

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The discovery of granite gravel in Hefei Jurassic backland basin, which came from the Dabie Shah or North Huaiyang, has a great significance for probing into uplift and exhumation of the Dabie orogenic belt. Lithochemical and isotope chronological analyses on the granite gravel in the Sanjianpu Formation and the Fenghuangtai Formation in Jinzhai County prove that post-orogenic granite was developed in the major provenance of the Hefei Basin; that is, Dabie Shah or North Huaiyang. Discordant lower intersection point age of zircon U-Pb of granite gravel is 40Ar/39about 214 Ma, and Ar/39Ar age of muscovite about 196 Ma,K-Ar age of K-spar about 181 Ma. The former is the diagenetic age of the sample, and the latter two represent the sealed ages of muscovite and K-spar respectively. The age of sedimentary rocks in which a lot of granite gravels appear in the sedimentary section may represent the newest age of the exhumation of the granite body, so we assume that the age is 166 Ma. Therefore, we calculated the uplift rates of the granite body from Late Triassic to early Middle Jurassic; that is about 0.08 km/Ma and 0.4-0.3 km/Ma in the early slowly uplifting stage and later fast uplifting stage respectively, after the formation of the body at 214 Ma. These results are basically identical to the uplifting ages of the Dabie ultrahigh pressure metamorphic (UHPM) belt and the North Huaiyang thrust belt.

  13. Application of Bomb Radiocarbon Chronologies to Shortfin Mako (Isurus oxyrinchus)

    Energy Technology Data Exchange (ETDEWEB)

    Ardizzone, D; Cailliet, G M; Natanson, L J; Andrews, A H; Kerr, L A; Brown, T A

    2007-07-16

    and the number of samples for MIA analysis was insufficient for some months. Hence, unequivocal validation of shortfin mako age estimates has yet to be accomplished. Atmospheric testing of thermonuclear devices in the 1950s and 1960s effectively doubled the natural atmospheric radiocarbon ({sup 14}C). The elevated {sup 14}C levels were first recorded in 1957-58, with a peak around 1963. As a consequence, {sup 14}C entered the ocean through gas exchange with the atmosphere at the ocean surface and in terrestrial runoff. Despite variable oceanographic conditions, a worldwide rise of the bomb {sup 14}C signal entered the ocean mixed layer as dissolved inorganic carbon (DIC) in 1957-58. The large amounts of {sup 14}C released from the bomb tests produced a signature that can be followed through time, throughout the marine food web, and into deeper waters. The marked increase of radiocarbon levels was first measured in the DIC of seawater and in biogenic marine carbonates of hermatypic corals in Florida. Subsequently, this record was documented in corals from other regions and in the thallus of rhodoliths. The accumulation of radiocarbon in the hard parts of most marine organisms in the mixed layer (such as fish otoliths and bivalves) was synchronous with the coral time-series. This technique has been used to validate age estimates and longevity of numerous bony fishes to date, as well as to establish bomb radiocarbon chronologies from different oceans. In the first application of this technique to lamnoid sharks, validated annual band-pair deposition in vertebral growth bands for the porbeagle (Lamna nasus) aged up to 26 years. Radiocarbon values from samples obtained from 15 porbeagle caught in the western North Atlantic Ocean (some of which were known-age) produced a chronology similar in magnitude to the reference carbonate chronology for that region. The observed phase shift of about 3 years was attributed to different sources of carbon between vertebrae and those for

  14. [Chinese pine tree ring width chronology and its relations to climatic conditions in Qianshan Mountains].

    Science.gov (United States)

    Chen, Zhen-Ju; Sun, Yu; He, Xing-Yuan; Chen, Wei; Shao, Xue-Mei; Zhang, Hua-Yu; Wang, Zhong-Yu; Liu, Xiao-Yu

    2007-10-01

    Taking Chinese pine in Qianshan Mountains as a sample, the tree ring width chronology including standard, residual, and Arstan chronologies was established. The results showed that the tree ring width of Chinese pine had a higher correlation with the temperature in May - July and in September - November, and significant positive correlations were observed between the tree ring width and the extreme minimum temperature in July and mean minimum temperature in September. The chronology had significant or very significant correlations with the extreme minimum temperature in December and next January, mean minimum temperature in January, annual precipitation, and the precipitation in April, May and last December. Chinese pine had stronger responses to the monthly/yearly water vapor pressure and relative humidity. The yearly and most monthly evaporation had negative effects on the growth, being most significant for the evaporation in April - July. The narrowed tree rings recorded by the chronology demonstrated the 30 times of extreme drought since 1 800. The growth of Chinese pine in Qianshan Mountains was also affected by the climate changes on global and hemisphere scales. There existed 11-, 23- and 50- year- common periodicity between the chronology and solar activity, and 10-, 20- and 45- year- common periodicity between the chronology and geomagnetic activity. PMID:18163297

  15. Chinese pine tree ring width chronology and its relation to climate conditions in the Qianshan Mountains

    Institute of Scientific and Technical Information of China (English)

    Zhenju CHEN; Yu SUN; Xingyuan HE; Wei CHEN; Xuemei SHAO; Huayu ZHANG; Zhongyu WANG; Xiaoyu LIU

    2008-01-01

    Taking Chinese pine in Qianshan Mountains as a sample, the tree ring width chronology including Standard, Residual, and Arstan chronologies was estab-lished. The results show that the tree ring width of Chinese pine is highly correlated with the temperatures from May to July and from September to November. Statistically significant positive correlations were observed between tree ring width and the extreme minimum temperatures in July and mean minimum temperatures in September. The chronology was significantly or very significantly correlated with extreme minimum temperatures in December and the following January, with mean min-imum temperatures in January, with annual precipita-tion and with precipitation in April, May and the following December. The Chinese pine responded strongly to the monthly/yearly water vapor pressure and relative humidity. Annual and largely monthly evaporation in April-July had a negative effect on tree growth, and was particularly striking for evaporation in April-July. The narrow tree rings recorded by the chro-nology demonstrated the 30 occasions of extreme drought since 1800. The growth of ChineSe pine in the Qianshan mountains were also affected by climate changes on a hemispheric and global scale. There were 11-, 23-and 50-year-common periodicities between the chronology and solar activity and 10-, 20- and 45-year-common periodicit-ies between the chronology and geomagnetic activity.

  16. Maintenance of cellular ATP level by caloric restriction correlates chronological survival of budding yeast

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Joon-Seok; Lee, Cheol-Koo, E-mail: cklee2005@korea.ac.kr

    2013-09-13

    Highlights: •CR decreases total ROS and mitochondrial superoxide during the chronological aging. •CR does not affect the levels of oxidative damage on protein and DNA. •CR contributes extension of chronological lifespan by maintenance of ATP level -- Abstract: The free radical theory of aging emphasizes cumulative oxidative damage in the genome and intracellular proteins due to reactive oxygen species (ROS), which is a major cause for aging. Caloric restriction (CR) has been known as a representative treatment that prevents aging; however, its mechanism of action remains elusive. Here, we show that CR extends the chronological lifespan (CLS) of budding yeast by maintaining cellular energy levels. CR reduced the generation of total ROS and mitochondrial superoxide; however, CR did not reduce the oxidative damage in proteins and DNA. Subsequently, calorie-restricted yeast had higher mitochondrial membrane potential (MMP), and it sustained consistent ATP levels during the process of chronological aging. Our results suggest that CR extends the survival of the chronologically aged cells by improving the efficiency of energy metabolism for the maintenance of the ATP level rather than reducing the global oxidative damage of proteins and DNA.

  17. Maintenance of cellular ATP level by caloric restriction correlates chronological survival of budding yeast

    International Nuclear Information System (INIS)

    Highlights: •CR decreases total ROS and mitochondrial superoxide during the chronological aging. •CR does not affect the levels of oxidative damage on protein and DNA. •CR contributes extension of chronological lifespan by maintenance of ATP level -- Abstract: The free radical theory of aging emphasizes cumulative oxidative damage in the genome and intracellular proteins due to reactive oxygen species (ROS), which is a major cause for aging. Caloric restriction (CR) has been known as a representative treatment that prevents aging; however, its mechanism of action remains elusive. Here, we show that CR extends the chronological lifespan (CLS) of budding yeast by maintaining cellular energy levels. CR reduced the generation of total ROS and mitochondrial superoxide; however, CR did not reduce the oxidative damage in proteins and DNA. Subsequently, calorie-restricted yeast had higher mitochondrial membrane potential (MMP), and it sustained consistent ATP levels during the process of chronological aging. Our results suggest that CR extends the survival of the chronologically aged cells by improving the efficiency of energy metabolism for the maintenance of the ATP level rather than reducing the global oxidative damage of proteins and DNA

  18. The chronology of the India-Asia collision

    Science.gov (United States)

    Garzanti, Eduardo; Hu, Xiumian

    2016-04-01

    Markedly diverging interpretations and incompatible scenarios have been proposed for the early stages of the Himalayan Orogeny. One view is that the northern Indian passive margin may have been involved in ophiolite obduction, arc-continent, or continent-continent collision as early as the Late Cretaceous. A different view is that India may have not come into contact with Asia until as late as the Oligo-Miocene. Ages assigned to the India-Asia collision have thus ranged rather freely from as old as 70 Ma to as young as 25-20 Ma, allowing researchers to select in remarkable liberty the age that fitted best with their lines of reasoning. In recent years, however, a growing body of stratigraphic evidence has constrained the chronology of collision with increasing accuracy and precision. Provenance analysis has ruled out early collision or ophiolite-obduction hypotheses, indicating that renewed terrigenous supply in the Maastrichtian to Danian (72-62 Ma) was derived from India in the south - rejuvenated by magmatic upwelling during the Deccan event - rather than from Asia or from an obducting ophiolite in the north (Garzanti and Hu, 2015). Integrated biostratigraphy and detrital-zircon chronostratigraphy has demonstrated that the first continent-continent contact and consequent disappearance of Neotethyan oceanic lithosphere at one point in south Tibet took place in the Selandian (59 ± 1 Ma; DeCelles et al., 2014; Wu et al., 2014; Hu et al., 2015). A major disconformity documenting tectonic uplift of carbonate platforms all along the Tethys Himalaya from the Gamba and Tingri areas of south Tibet to the Zanskar Range of the NW Himalaya, allowed dating the arrival of the orogenic wave in the inner part of the northern Indian passive margin around the Paleocene/Eocene boundary (ca. 56 Ma; Garzanti et al., 1987; Li et al., 2015). Shallow-marine seaways linked with Neotethys persisted in the Himalaya until the mid-Ypresian (ca. 50 Ma), when they were finally filled by

  19. Progress in the Early Solar System Chronology: A Sketch of an Ever-Changing Landscape

    Science.gov (United States)

    Amelin, Yuri; Yin, Q.-Z.; Krot, A. N.; Bouvier, A.; Wadhwa, M.; Kleine, T.; Nyquist, L. E.

    2011-01-01

    The years since the Workshop on the Chronology of Meteorites and the Early Solar System, are marked with ongoing progress in cosmochronology. Rapid improvements in techniques, discovery of new meteorites unlike any previously known, and findings that what was deemed well established constants are actually variables, will be reflected in an updated review of the solar system chronology we are currently preparing. Along with updating the database of meteorite ages, it will involve development of a set of criteria for evaluation of accuracy and consistency of isotopic dates across the entire range of meteorite classes and isotope chronometer systems. Here we present some ideas on what we think is important in meteorite chronology, and invite the cosmochemistry community to discuss them.

  20. 14C dates from Tel Rehov: Iron-Age chronology, pharaohs, and Hebrew kings.

    Science.gov (United States)

    Bruins, Hendrik J; van der Plicht, Johannes; Mazar, Amihai

    2003-04-11

    Stratified radiocarbon dates provide an independent chronological link between archaeological layers and historical data. The invasion by Pharaoh Shoshenq I (Shishak) is a key historical synchronism, approximately 925 B.C.E., mentioned in both Egyptian inscriptions and the Hebrew Bible. The list of places raided by Shoshenq, mentioned at Karnak (Egypt), includes Rehov (Israel). The site yielded a consistent series of radiocarbon dates from the 12th to 9th century B.C.E. Our results (i) suggest a revised Iron-Age chronology; (ii) date an archaeological stratum to Shoshenq's campaign; (iii) indicate the similarity of "Solomonic" and "Omride" pottery; and (iv) provide correlation with Greece and Cyprus.

  1. The Catacomb cultures of the North-West Caspian steppe : C-14 chronology, reservoir effect, and paleodiet

    NARCIS (Netherlands)

    Shishlina, N. I.; van der Plicht, J.; Hedges, R. E. M.; Zazovskaya, E. P.; Sevastyanov, V. S.; Chichagova, O. A.

    2007-01-01

    For the Bronze Age Catacomb cultures of the North-West Caspian steppe area in Russia, there is a conflict between the traditional relative archaeological chronology and the chronology based on radiocarbon dates. We show that this conflict can be explained largely by the fact that most dates have bee

  2. The WAIS Divide deep ice core WD2014 chronology - Part 2: Annual-layer counting (0-31 ka BP)

    Science.gov (United States)

    Sigl, Michael; Fudge, Tyler J.; Winstrup, Mai; Cole-Dai, Jihong; Ferris, David; McConnell, Joseph R.; Taylor, Ken C.; Welten, Kees C.; Woodruff, Thomas E.; Adolphi, Florian; Bisiaux, Marion; Brook, Edward J.; Buizert, Christo; Caffee, Marc W.; Dunbar, Nelia W.; Edwards, Ross; Geng, Lei; Iverson, Nels; Koffman, Bess; Layman, Lawrence; Maselli, Olivia J.; McGwire, Kenneth; Muscheler, Raimund; Nishiizumi, Kunihiko; Pasteris, Daniel R.; Rhodes, Rachael H.; Sowers, Todd A.

    2016-03-01

    We present the WD2014 chronology for the upper part (0-2850 m; 31.2 ka BP) of the West Antarctic Ice Sheet (WAIS) Divide (WD) ice core. The chronology is based on counting of annual layers observed in the chemical, dust and electrical conductivity records. These layers are caused by seasonal changes in the source, transport, and deposition of aerosols. The measurements were interpreted manually and with the aid of two automated methods. We validated the chronology by comparing to two high-accuracy, absolutely dated chronologies. For the Holocene, the cosmogenic isotope records of 10Be from WAIS Divide and 14C for IntCal13 demonstrated that WD2014 was consistently accurate to better than 0.5 % of the age. For the glacial period, comparisons to the Hulu Cave chronology demonstrated that WD2014 had an accuracy of better than 1 % of the age at three abrupt climate change events between 27 and 31 ka. WD2014 has consistently younger ages than Greenland ice core chronologies during most of the Holocene. For the Younger Dryas-Preboreal transition (11.595 ka; 24 years younger) and the Bølling-Allerød Warming (14.621 ka; 7 years younger), WD2014 ages are within the combined uncertainties of the timescales. Given its high accuracy, WD2014 can become a reference chronology for the Southern Hemisphere, with synchronization to other chronologies feasible using high-quality proxies of volcanism, solar activity, atmospheric mineral dust, and atmospheric methane concentrations.

  3. Tree-Ring Chronology of Pedunculate Oak (Quercus robur and its Potential for Development of Dendrochronological Research in Croatia

    Directory of Open Access Journals (Sweden)

    Katarina Čufar

    2014-06-01

    Full Text Available We present the local tree-ring chronology of pedunculate oak (Qercus robur from Kobiljak near Zagreb, Croatia (16º09’ E, 45º49’ N, 140 m a.s.l.. The chronology is based on 17 trees and is 127 years long and covers the period of 1883-2009. The well replicated part of the residual version of the ARSTAN chronology with SSS>0.80 (interval of 88 years, period 1922-2009 was used for dendroclimatological analysis, which showed that June precipitation has positive and temperature has negative effect on tree-ring variation. Comparison with 40 available oak chronologies from the surrounding countries confi rmed its good teleconnection with 2 local oak chronologies from Austria, 2 from Hungary, and 3 from Slovenia. It also exhibits good heteroconnection, i.e. similarity with chronologies of beech (Fagus sylvatica, from various sites in Slovenia. The similarities can be ascribed to response to common climatic factors. The results indicate that the chronology could be a good reference point for constructing a longer regional chronology in Croatia and surrounding countries, which could be used for different purposes including dating of objects of cultural heritage.

  4. Chronological and subjective age differences in flourishing mental health and major depressive episode.

    NARCIS (Netherlands)

    Keyes, C.L.M.; Westerhof, G.J.

    2012-01-01

    Mental health is more than the absence of psychopathology, but few studies use positive mental health along with a measure of past year major depressive episode (MDE). This study addresses this gap by investigating the association of MDE and flourishing mental health (FMH) with chronological age and

  5. Third-molar development in relation to chronologic age in young adults of central China.

    Science.gov (United States)

    Bai, Yuming; Mao, Jing; Zhu, Shengrong; Wei, Wei

    2008-08-01

    The estimation of chronologic age based on the stages of third-molar development was evaluated by using the eight stages (A-H) method of Demirjian and the third-molar development was compared, in terms of sex and age, with results of previous studies. The samples consisted of 291 orthopantomograms from young Chinese subjects of known chronologic age and sex (including 139 males with a mean age of 14.67+/-3.62 y and 152 females with a mean age of 14.85+/-3.70 y). Statistical analysis was performed by employing the Mann-Whitney U-test and the t-test. Regression analysis was conducted to obtain regression formulas for calculating dental age from the chronologic age. Our results showed statistically significant differences (Pthird-molar development between males and females, at the calcification stages D, E and H. And a strong correlation was found between age and third-molar development in both males (r (2)=0.65) and females (r (2)=0.61). New equations (Age=8.76+1.32 Development stage) for estimating chronologic age were derived. It is concluded that third-molar genesis took place earlier in males than in females. The use of third molars as a developmental marker is appropriate in young adults of Central China. The formula obtained in the present study can be used as a guide for estimation of dental maturity and a standard for age estimation for young adults of Central China.

  6. The absolute chronology and thermal processing of solids in the solar protoplanetary disk

    DEFF Research Database (Denmark)

    Connelly, James Norman; Bizzarro, Martin; Krot, Alexander N.;

    2012-01-01

    Transient heating events that formed calcium-aluminum - rich inclusions (CAIs) and chondrules are fundamental processes in the evolution of the solar protoplanetary disk, but their chronology is not understood. Using U-corrected Pb-Pb dating, we determined absolute ages of individual CAIs...

  7. Legal Recognition of Same-Sex Couples in the Countries of the World : a Chronological Overview

    NARCIS (Netherlands)

    Waaldijk, C.; Marsh, V.

    2011-01-01

    Chronological overview of countries (and parts of countries) that have taken some major steps in legally recognising same-sex couples: legal recognition of non-registered same-sex cohabitation, introduction of a form of registered partnership, opening up of adoption and/or marriage for same-sex part

  8. The double-body glyphs and palaeographic chronology in the rongorongo script

    DEFF Research Database (Denmark)

    Wieczorek, Rafal

    2011-01-01

    . A reading of the related literature shows more scribal differences in other rongorongo glyphs as well. By combining various scribal differences together with the analysis of hollow-belly and 099/522 glyphs, most of the existing rongorongo inscriptions can be classified into a chronological list of texts...

  9. Current issues in late Middle Palaeolithic chronology : New assessments from Northern Iberia

    NARCIS (Netherlands)

    Maroto, Julia; Vaquero, Manuel; Arrizabalaga, Alvaro; Baena, Javier; Baquedano, Enrique; Jorda, Jesus; Julia, Ramon; Montes, Ramon; Van Der Plicht, Johannes; Rasines, Pedro; Wood, Rachel

    2012-01-01

    The Iberian Peninsula plays a central role in the current debates on the Middle-Upper Palaeolithic transition and the Neanderthal extinction. This is largely due to the chronological data which some authors have suggested show a clear divide between Northern Iberia, where the Upper Palaeolithic appe

  10. Legal Recognition of Same-Sex Couples in the Countries of the World: a Chronological Overview

    OpenAIRE

    Waaldijk, C.; Marsh, V

    2011-01-01

    Chronological overview of countries (and parts of countries) that have taken some major steps in legally recognising same-sex couples: legal recognition of non-registered same-sex cohabitation, introduction of a form of registered partnership, opening up of adoption and/or marriage for same-sex partners.

  11. The epigenetic clock and telomere length are independently associated with chronological age and mortality

    Science.gov (United States)

    Marioni, Riccardo E; Harris, Sarah E; Shah, Sonia; McRae, Allan F; von Zglinicki, Thomas; Martin-Ruiz, Carmen; Wray, Naomi R; Visscher, Peter M; Deary, Ian J

    2016-01-01

    Background: Telomere length and DNA methylation have been proposed as biological clock measures that track chronological age. Whether they change in tandem, or contribute independently to the prediction of chronological age, is not known. Methods: We address these points using data from two Scottish cohorts: the Lothian Birth Cohorts of 1921 (LBC1921) and 1936 (LBC1936). Telomere length and epigenetic clock estimates from DNA methylation were measured in 920 LBC1936 participants (ages 70, 73 and 76 years) and in 414 LBC1921 participants (ages 79, 87 and 90 years). Results: The epigenetic clock changed over time at roughly the same rate as chronological age in both cohorts. Telomere length decreased at 48–67 base pairs per year on average. Weak, non-significant correlations were found between epigenetic clock estimates and telomere length. Telomere length explained 6.6% of the variance in age in LBC1921, the epigenetic clock explained 10.0%, and combined they explained 17.3% (all P epigenetic age was linked to a 22% increased mortality risk (P = 2.6 × 10−4) whereas, in the same model, a one standard deviation increase in baseline telomere length was independently linked to an 11% decreased mortality risk (P = 0.06). Conclusions: These results suggest that telomere length and epigenetic clock estimates are independent predictors of chronological age and mortality risk. PMID:27075770

  12. The significance of peroxisome function in chronological aging of Saccharomyces cerevisiae

    NARCIS (Netherlands)

    Lefevre, Sophie D.; van Roermund, Carlo W.; Wanders, Ronald J. A.; Veenhuis, Marten; van der Klei, Ida J.

    2013-01-01

    Summary We studied the chronological lifespan of glucose-grown Saccharomyces cerevisiae in relation to the function of intact peroxisomes. We analyzed four different peroxisome-deficient (pex) phenotypes. These included Delta pex3 cells that lack peroxisomal membranes and in which all peroxisomal pr

  13. Niobium-Zirconium Systematics of Meteoritic Rutiles: Application to the Chronology of Mesosiderites

    Science.gov (United States)

    Haba, M. K.; Lai, Y.-J.; Yamaguchi, A.; Schönbächler, M.

    2016-08-01

    Nb-Zr systematics of rutiles from mesosiderites was obtained using MC-ICPMS. Our data show an initial 92Nb/93Nb ratio of ~10-5 in the mesosiderite formation region and provide chronological constraint on the early evolution of the parent body.

  14. The effects of chronological age and size on toxicity of zinc to juvenile brown trout

    Science.gov (United States)

    A series of toxicity tests were conducted to investigate the role of chronological age and organism weight on zinc tolerance in juvenile brown trout (Salmo trutta). Four different incubation temperatures were used to control the maturation of the juveniles prior to zinc exposure...

  15. Quantitative and qualitative approaches to identifying migration chronology in a continental migrant.

    Directory of Open Access Journals (Sweden)

    William S Beatty

    Full Text Available The degree to which extrinsic factors influence migration chronology in North American waterfowl has not been quantified, particularly for dabbling ducks. Previous studies have examined waterfowl migration using various methods, however, quantitative approaches to define avian migration chronology over broad spatio-temporal scales are limited, and the implications for using different approaches have not been assessed. We used movement data from 19 female adult mallards (Anas platyrhynchos equipped with solar-powered global positioning system satellite transmitters to evaluate two individual level approaches for quantifying migration chronology. The first approach defined migration based on individual movements among geopolitical boundaries (state, provincial, international, whereas the second method modeled net displacement as a function of time using nonlinear models. Differences in migration chronologies identified by each of the approaches were examined with analysis of variance. The geopolitical method identified mean autumn migration midpoints at 15 November 2010 and 13 November 2011, whereas the net displacement method identified midpoints at 15 November 2010 and 14 November 2011. The mean midpoints for spring migration were 3 April 2011 and 20 March 2012 using the geopolitical method and 31 March 2011 and 22 March 2012 using the net displacement method. The duration, initiation date, midpoint, and termination date for both autumn and spring migration did not differ between the two individual level approaches. Although we did not detect differences in migration parameters between the different approaches, the net displacement metric offers broad potential to address questions in movement ecology for migrating species. Ultimately, an objective definition of migration chronology will allow researchers to obtain a comprehensive understanding of the extrinsic factors that drive migration at the individual and population levels. As a result

  16. Quantitative and qualitative approaches to identifying migration chronology in a continental migrant

    Science.gov (United States)

    Beatty, William S.; Kesler, Dylan C.; Webb, Elisabeth B.; Raedeke, Andrew H.; Naylor, Luke W.; Humburg, Dale D.

    2013-01-01

    The degree to which extrinsic factors influence migration chronology in North American waterfowl has not been quantified, particularly for dabbling ducks. Previous studies have examined waterfowl migration using various methods, however, quantitative approaches to define avian migration chronology over broad spatio-temporal scales are limited, and the implications for using different approaches have not been assessed. We used movement data from 19 female adult mallards (Anas platyrhynchos) equipped with solar-powered global positioning system satellite transmitters to evaluate two individual level approaches for quantifying migration chronology. The first approach defined migration based on individual movements among geopolitical boundaries (state, provincial, international), whereas the second method modeled net displacement as a function of time using nonlinear models. Differences in migration chronologies identified by each of the approaches were examined with analysis of variance. The geopolitical method identified mean autumn migration midpoints at 15 November 2010 and 13 November 2011, whereas the net displacement method identified midpoints at 15 November 2010 and 14 November 2011. The mean midpoints for spring migration were 3 April 2011 and 20 March 2012 using the geopolitical method and 31 March 2011 and 22 March 2012 using the net displacement method. The duration, initiation date, midpoint, and termination date for both autumn and spring migration did not differ between the two individual level approaches. Although we did not detect differences in migration parameters between the different approaches, the net displacement metric offers broad potential to address questions in movement ecology for migrating species. Ultimately, an objective definition of migration chronology will allow researchers to obtain a comprehensive understanding of the extrinsic factors that drive migration at the individual and population levels. As a result, targeted

  17. A Date Recovery System launched for chronological studies in ancient China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Benefited from the performance of the Xia-Shang-Zhou Chronology Project (XSZP) in China and our new astronomical chronology method designed and processed for Chinese particular 60-day-cycle Ganzhi (the heavenly stems and earthly branches) date records, we launch a Date Recovery System (DRS) for ancient China. Of high analysis function, this software can recover and convert the complete or incomplete date information originally from Ganzhi style in the historical period of China to the Gregorian Calendar System, which may have wide applications in the area of literary history, archaeology and cultural relic, etc., and solve the Goldbach Puzzles of Chinese nations. As an example, we give the detailed process for the sculptures on four bronze wares with the Ganzhi data and afterwards employ this software and provide their possible dates corresponding to Gregorian system.

  18. Chronology for the Aegean Late Bronze Age 1700-1400 B.C.

    Science.gov (United States)

    Manning, Sturt W; Ramsey, Christopher Bronk; Kutschera, Walter; Higham, Thomas; Kromer, Bernd; Steier, Peter; Wild, Eva M

    2006-04-28

    Radiocarbon (carbon-14) data from the Aegean Bronze Age 1700-1400 B.C. show that the Santorini (Thera) eruption must have occurred in the late 17th century B.C. By using carbon-14 dates from the surrounding region, cultural phases, and Bayesian statistical analysis, we established a chronology for the initial Aegean Late Bronze Age cultural phases (Late Minoan IA, IB, and II). This chronology contrasts with conventional archaeological dates and cultural synthesis: stretching out the Late Minoan IA, IB, and II phases by approximately 100 years and requiring reassessment of standard interpretations of associations between the Egyptian and Near Eastern historical dates and phases and those in the Aegean and Cyprus in the mid-second millennium B.C. PMID:16645092

  19. A Date Recovery System launched for chronological studies in ancient China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Benefited from the performance of the Xia-Shang-Zhou Chronology Project(XSZP) in China and our new astronomical chronology method designed and processed for Chinese particular 60-day-cycle Ganzhi(the heavenly stems and earthly branches)date records,we launch a Date Recovery System(DRS)for ancient China. Of high analysis function,this software can recover and convert the complete or incomplete date information originally from Ganzhi style in the historical period of China to the Gregorian Calendar System,which may have wide applications in the area of literary history,archaeology and cultural relic,etc.,and solve the Goldbach Puzzles of Chinese nations.As an example,we give the detailed process for the sculptures on four bronze wares with the Ganzhi data and afterwards employ this software and provide their possible dates corresponding to Gregorian system.

  20. The chronology of Castelo de Castro Marim. An Iron Age settlement

    Directory of Open Access Journals (Sweden)

    Ana Margarida Arruda

    2014-01-01

    Full Text Available The Iron Age diachrony of Castro Marim occupation has been established with the stratigraphic sequence and the materials recovered in the different levels. Based on these data we have already presented chronological proposals for the four phases, which we could also characterize in relation with architectural plans and with the archaeological materials. The collection of organic material at all levels of the stratigraphic sequence allowed us to obtain absolute dates, carried out on shells and charcoals. In this work, the data from the radiocarbon chronology are presented and discussed by themselves and related with the others. The relationship between the 14C dates and those obtained by morphological analysis of the materials collected along the stratigraphic sequence bring more solid bases to analyze the diachronic evolution of Castro Marim Iron Age.

  1. Chronology of Postglacial Eruptive Activity and Calculation of Eruption Probabilities for Medicine Lake Volcano, Northern California

    Science.gov (United States)

    Nathenson, Manuel; Donnelly-Nolan, Julie M.; Champion, Duane E.; Lowenstern, Jacob B.

    2007-01-01

    Medicine Lake volcano has had 4 eruptive episodes in its postglacial history (since 13,000 years ago) comprising 16 eruptions. Time intervals between events within the episodes are relatively short, whereas time intervals between the episodes are much longer. An updated radiocarbon chronology for these eruptions is presented that uses paleomagnetic data to constrain the choice of calibrated ages. This chronology is used with exponential, Weibull, and mixed-exponential probability distributions to model the data for time intervals between eruptions. The mixed exponential distribution is the best match to the data and provides estimates for the conditional probability of a future eruption given the time since the last eruption. The probability of an eruption at Medicine Lake volcano in the next year from today is 0.00028.

  2. Protocol adaptations to conduct Systematic Literature Reviews in Software Engineering: a chronological study

    Directory of Open Access Journals (Sweden)

    Samuel Sepúlveda

    2015-12-01

    Full Text Available Systematic literature reviews (SLR have reached a considerable level of adoption in Software Engineering (SE, how-ever protocol adaptations for its implementation remain tangentially addressed. This work provides a chronological framework for the use and adaptation of the SLR protocol, including its current status. A systematic literature search was performed, reviewing a set of twelve articles being selected in accordance with the inclusion and exclusion criteria between 2004 and 2013, using digital data sources recognized by the SE community. A chronological framework is provided that includes the current state of the protocol adaptations to conduct SLR in SE. The results indicate areas where the quantity and quality of investigations needs to be increased and the identi- fication of the main proposals providing adaptations for the protocol conducting SLR in SE.

  3. Energy History Chronology from World War II to the Present [1982

    Science.gov (United States)

    Dean, P. C.

    1982-08-01

    This report provides a basic guide to the major Presidential, Legislative, Judicial, and Federal agency actions relating to energy policy, research, development, and regulation in recent years. The chronology is arranged synoptically, allowing users to reference easily the historical context in which each event occurred. Summaries of Presidential, Legislative, and Judicial actions relating to energy, rosters of federal energy officials, and a genealogy of federal energy agencies are also provided in separate appendices. The Energy History Chronology was prepared in conjunction with the History Division's series of pamphlets on the Institutional Origins of the Department of Energy. The series includes concise histories of the Department of Energy, the Energy Research and Development Administration, the Federal Energy Administration, and the Atomic Energy Commission. All significant events and achievements noted in the institutional history are also listed.

  4. Chronological analysis of architectural and acoustical indices in music performance halls.

    Science.gov (United States)

    Kwon, Youngmin; Siebein, Gary W

    2007-05-01

    This study aims to identify the changes in architectural and acoustical indices in halls for music performance built in the 18th through the 20th Centuries. Seventy-one halls are classified in five specific periods from the Classical Period (1751-1820) to the Contemporary Period (1981-2000) based on chronology in music and architectural acoustics. Architectural indices such as room shape, seating capacity, room volume, balcony configuration, and the like as well as acoustical indices such as RT, EDT, G, C80, IACC, and the like for the halls found in the literature are chronologically tabulated and statistically analyzed to identify trends and relationships in architectural and acoustical design for each of the historical periods identified. Some indices appear correlated with each other. PMID:17550169

  5. Discrimination of speech sounds by children with dyslexia: comparisons with chronological age and reading level controls.

    Science.gov (United States)

    Bogliotti, C; Serniclaes, W; Messaoud-Galusi, S; Sprenger-Charolles, L

    2008-10-01

    Previous studies have shown that children suffering from developmental dyslexia have a deficit in categorical perception of speech sounds. The aim of the current study was to better understand the nature of this categorical perception deficit. In this study, categorical perception skills of children with dyslexia were compared with those of chronological age and reading level controls. Children identified and discriminated /do-to/ syllables along a voice onset time (VOT) continuum. Results showed that children with dyslexia discriminated among phonemically contrastive pairs less accurately than did chronological age and reading level controls and also showed higher sensitivity in the discrimination of allophonic contrasts. These results suggest that children with dyslexia perceive speech with allophonic units rather than phonemic units. The origin of allophonic perception in the course of perceptual development and its implication for reading acquisition are discussed. PMID:18462745

  6. Mineralogy, Petrology, Chronology, and Exposure History of the Chelyabinsk Meteorite and Parent Body

    Science.gov (United States)

    Righter, K.; Abell, P.; Agresti, D.; Berger, E. L.; Burton, A. S.; Delaney, J. S.; Fries, M. D.; Gibson, E. K.; Harrington, R.; Herzog, G. F.; Keller, L. P.; Locke, D.; Lindsay, F.; McCoy, T. J.; Morris, R. V.; Nagao, K.; Nakamura-Messenger, K.; Niles, P. B.; Nyquist, L.; Park, J.; Peng, Z. X.; Shih, C. Y.; Simon, J. I.; Swisher, C. C., III; Tappa, M.

    2015-01-01

    The Chelyabinsk meteorite fall on February 15, 2013 attracted much more attention worldwide than do most falls. A consortium led by JSC received 3 masses of Chelyabinsk (Chel-101, -102, -103) that were collected shortly after the fall and handled with care to minimize contamination. Initial studies were reported in 2013; we have studied these samples with a wide range of analytical techniques to better understand the mineralogy, petrology, chronology and exposure history of the Chelyabinsk parent body.

  7. A CHRONOLOGICAL FRAMEWORK FOR THE HOLOCENE VEGETATIONAL HISTORY OF CENTRAL MINNESOTA: THE STEEL LAKE POLLEN RECORD

    Energy Technology Data Exchange (ETDEWEB)

    Wright, H E; Stefanova, I; Tian, J; Brown, T A; Hu, F S

    2003-11-10

    Paleorecords from Minnesota and adjacent areas have often been used to evaluate large-scale climatic processes in the mid-continent of North America. However, most of these records are compromised by chronological flaws, making problematic any comparisons with climatic interpretations based on other records (e.g., GISP2 in Greenland). We report here a high-resolution pollen record with a secure chronology constrained by 26 {sup 14}C dates on terrestrial macrofossils from Steel Lake, central Minnesota. About 11,200 years ago (calibrated yr BP) the late-glacial Picea forest near Steel Lake was succeeded abruptly by Pinus banksiana and/or resinosa. The Pinus forest began to open 9.4 ka cal BP with the expansion of prairie taxa, and a pine parkland or savanna prevailed until about 8 ka cal BP, when Quercus replaced Pinus to become the dominant tree in the prairie areas for 4500 years. The close chronological control permits the correlation of key vegetational changes with those at other reliably dated sites in the eastern Dakotas and in Minnesota, suggesting that the abrupt decline of the spruce forest was time-transgressive from southwest to northeast during 2000 years, and that the development of prairie was time-transgressive in the same direction over 2600 years. Correlation of key pollen horizons at Steel Lake with those in the high-resolution pollen profiles of Elk Lake, ca. 50 km northwest of Steel Lake, suggests that the well-known Elk Lake varve chronology for the early Holocene is about 1000 years too young.

  8. Third-Molar Development in Relation to Chronologic Age in Young Adults of Central China

    Institute of Scientific and Technical Information of China (English)

    Yuming BAI; Jing MAO; Shengrong ZHU; Wei WEI

    2008-01-01

    The estimation of chronologic age based on the stages of third-molar development was evaluated by using the eight stages (A-H) method of Demirjian and the third-molar development was compared, in terms of sex and age, with results of previous studies. The samples consisted of 291orthopantomograms from young Chinese subjects of known chronologic age and sex (including 139males with a mean age of 14.67±3.62 y and 152 females with a mean age of 14.85±3.70 y). Statistical analysis was performed by employing the Mann-Whitney U-test and the t-test. Regression analysis was conducted to obtain regression formulas for calculating dental age from the chronologic age. Our results showed statistically significant differences (P<0.05) in third-molar development between males and females, at the calcification stages D, E and H. And a strong correlation was found between age and third-molar development in both males (r2=0.65) and females (r2=0.61). New equations (Age=8.76+1.32 Development stage) for estimating chronologic age were derived. It is concluded that third-molar genesis took place earlier in males than in females. The use of third molars as a developmental marker is appropriate in young adults of Central China. The formula obtained in the present study can be used as a guide for estimation of dental maturity and a standard for age estimation for young adults of Central China.

  9. Luminescence chronology of a second millenium BCE settlement near Porbandar on the Gujarat coast, India

    Digital Repository Service at National Institute of Oceanography (India)

    Gaur, A.S.; Thomas; Vora, K.H.; Sundaresh

    Luminescence Chronology of a Second Millennium BCE Settlement near Porbandar on the GUjarat Coast, India - A.S. Gaur, P./. Thomas*, K.H. Vora and Sundaresh An onshore excavation at Bokhira (Porbandar) on the Saurashtra coast has revealed a late Harappan.... SAR-OSL dating of heated materials collected from different archaeological sites in India has been attempted recently (Thomas et 01. In Press), and is shown to be a reliable dating method when compared to TL dating. SAMPLE PREPARATION AND MEASUREMENT...

  10. Archaeoastronomy and the chronology of the Temple of Jupiter at Baalbek

    CERN Document Server

    Magli, Giulio

    2016-01-01

    One of the most complex architectural feats ever conceived is the magnificent temple of Jupiter at Baalbek, Lebanon. Several issues remain unsolved about this site, and in particular the chronology and dating of the two podia and the true nature of the cult. We present here some hints coming from orientation and from other features of the temple, which seem to point to a unified project of both podia, originally conceived under Herod the Great.

  11. A microarray-based genetic screen for yeast chronological aging factors.

    Directory of Open Access Journals (Sweden)

    Mirela Matecic

    2010-04-01

    Full Text Available Model organisms have played an important role in the elucidation of multiple genes and cellular processes that regulate aging. In this study we utilized the budding yeast, Saccharomyces cerevisiae, in a large-scale screen for genes that function in the regulation of chronological lifespan, which is defined by the number of days that non-dividing cells remain viable. A pooled collection of viable haploid gene deletion mutants, each tagged with unique identifying DNA "bar-code" sequences was chronologically aged in liquid culture. Viable mutants in the aging population were selected at several time points and then detected using a microarray DNA hybridization technique that quantifies abundance of the barcode tags. Multiple short- and long-lived mutants were identified using this approach. Among the confirmed short-lived mutants were those defective for autophagy, indicating a key requirement for the recycling of cellular organelles in longevity. Defects in autophagy also prevented lifespan extension induced by limitation of amino acids in the growth media. Among the confirmed long-lived mutants were those defective in the highly conserved de novo purine biosynthesis pathway (the ADE genes, which ultimately produces IMP and AMP. Blocking this pathway extended lifespan to the same degree as calorie (glucose restriction. A recently discovered cell-extrinsic mechanism of chronological aging involving acetic acid secretion and toxicity was suppressed in a long-lived ade4Delta mutant and exacerbated by a short-lived atg16Delta autophagy mutant. The identification of multiple novel effectors of yeast chronological lifespan will greatly aid in the elucidation of mechanisms that cells and organisms utilize in slowing down the aging process.

  12. Aging on a different scale - chronological versus pathology-related aging.

    OpenAIRE

    Melis, J.P.; Jonker, M.J.; Vijg, J.; Hoeijmakers, J. H.; Breit, T.M.; Steeg, van der, A.F.W.

    2013-01-01

    In the next decades the elderly population will increase dramatically, demanding appropriate solutions in health care and aging research focusing on healthy aging to prevent high burdens and costs in health care. For this, research targeting tissue-specific and individual aging is paramount to make the necessary progression in aging research. In a recently published study we have attempted to make a step interpreting aging data on chronological as well as pathological scale. For this, we samp...

  13. Cultural and Chronological Horizons and the Problem of the Early Sarmatian Culture Formation

    Directory of Open Access Journals (Sweden)

    Yablonsky Leonid Teodorovich

    2015-12-01

    Full Text Available On the materials of Eurasian early nomads’ archaeology we highlight the South Ural cultural and historical area (UCHA. Geographically it includes steppe regions of West Kazakhstan, Chelyabinsk and Orenburg regions, steppe and forest steppe zones of the Republic of Bashkortostan. There were similar cultural processes that led to the Early Sarmatian archaeological culture formation in the Early Iron Age. Under the cultural and chronological horizon we understand the geographic region that is significantly larger than UCHA. Practically it has no geographic boundaries. Specificity of the horizon is that at a certain chronological stage (phase artifacts and their complexes, signs of spiritual culture are widely distributed that will mark the horizon – the horizon markers such as well known Scythian triad. Global chronological scheme of the Southern Trans-Urals cultural and historical area can be represented as follows: “Sauromatian” cultural and chronological horizon – the second half of the 6th – the end of the 4th (3rd centuries B.C. – Phase “A” – the second half of the 6th – the middle of the 5th centuries B.C. – Phase “B” – the second half of the 5th – the third quarter of the 4th centuries B.C. – Phase “C” – the third quarter of the 4th – the 3rd century B.C. Typologically the burial grounds like Filippovka I and Perevolochan can be attributed to the Early-Sarmatian archaeological culture, i.e. to the time of the ethnic consciousness formation of suspected archaeological Early Sarmatians. In this period ordinary mounds and graves appear along with the elite ones. It is advisable to consider the sites of the “Sauromatian” and Early-Sarmatian cultures of the South Urals of the end of the 5th-3rd centuries B.C. as a single culture of the early nomads.

  14. Rewriting the Central European Early Bronze Age Chronology: Evidence from Large-Scale Radiocarbon Dating.

    Directory of Open Access Journals (Sweden)

    Philipp W Stockhammer

    Full Text Available The transition from the Neolithic to the Early Bronze Age in Central Europe has often been considered as a supra-regional uniform process, which led to the growing mastery of the new bronze technology. Since the 1920s, archaeologists have divided the Early Bronze Age into two chronological phases (Bronze A1 and A2, which were also seen as stages of technical progress. On the basis of the early radiocarbon dates from the cemetery of Singen, southern Germany, the beginning of the Early Bronze Age in Central Europe was originally dated around 2300/2200 BC and the transition to more complex casting techniques (i.e., Bronze A2 around 2000 BC. On the basis of 140 newly radiocarbon dated human remains from Final Neolithic, Early and Middle Bronze Age cemeteries south of Augsburg (Bavaria and a re-dating of ten graves from the cemetery of Singen, we propose a significantly different dating range, which forces us to re-think the traditional relative and absolute chronologies as well as the narrative of technical development. We are now able to date the beginning of the Early Bronze Age to around 2150 BC and its end to around 1700 BC. Moreover, there is no transition between Bronze (Bz A1 and Bronze (Bz A2, but a complete overlap between the type objects of the two phases from 1900-1700 BC. We thus present a revised chronology of the assumed diagnostic type objects of the Early Bronze Age and recommend a radiocarbon-based view on the development of the material culture. Finally, we propose that the traditional phases Bz A1 and Bz A2 do not represent a chronological sequence, but regionally different social phenomena connected to the willingness of local actors to appropriate the new bronze technology.

  15. Reconstructions of Columbia River streamflow from tree-ring chronologies in the Pacific Northwest, USA

    Science.gov (United States)

    Littell, Jeremy; Pederson, Gregory T.; Gray, Stephen T.; Tjoelker, Michael; Hamlet, Alan F.; Woodhouse, Connie A.

    2016-01-01

    We developed Columbia River streamflow reconstructions using a network of existing, new, and updated tree-ring records sensitive to the main climatic factors governing discharge. Reconstruction quality is enhanced by incorporating tree-ring chronologies where high snowpack limits growth, which better represent the contribution of cool-season precipitation to flow than chronologies from trees positively sensitive to hydroclimate alone. The best performing reconstruction (back to 1609 CE) explains 59% of the historical variability and the longest reconstruction (back to 1502 CE) explains 52% of the variability. Droughts similar to the high-intensity, long-duration low flows observed during the 1920s and 1940s are rare, but occurred in the early 1500s and 1630s-1640s. The lowest Columbia flow events appear to be reflected in chronologies both positively and negatively related to streamflow, implying low snowpack and possibly low warm-season precipitation. High flows of magnitudes observed in the instrumental record appear to have been relatively common, and high flows from the 1680s to 1740s exceeded the magnitude and duration of observed wet periods in the late-19th and 20th Century. Comparisons between the Columbia River reconstructions and future projections of streamflow derived from global climate and hydrologic models show the potential for increased hydrologic variability, which could present challenges for managing water in the face of competing demands

  16. Evaluation of third molar development in the estimation of chronological age.

    Science.gov (United States)

    Soares, Caio Belém Rodrigues Barros; Figueiroa, José Natal; Dantas, Renata Moura Xavier; Kurita, Lúcio Mitsuo; Pontual, Andréa dos Anjos; Ramos-Perez, Flávia Maria de Moraes; Perez, Danyel Elias da Cruz; Pontual, Maria Luiza dos Anjos

    2015-09-01

    The purpose of this study was to evaluate the correlation between chronological age and the degree of third molar mineralization by Demirjian's developmental stages (Demirjian et al., 1973) using panoramic radiography. From a total of 11.396 digital panoramic radiographs of patients from three oral radiology private clinics from the northeast region of Brazil, obtained from January to June 2009, 2097 radiographic images from patients aged between 6 and 22 years were selected. The images were analyzed individually by two obsevers using a 21-inch computer screen and Windows Picture and Fax Viewer. Reliability was achieved by intra- and interobserver evaluation, using the Kappa test. Chronological age, calcification stage, gender and third molar were interrelated using a multiple linear regression model, considering age as a response variable. There was reliability with Demirjian et al.'s developmental stage assesment, displaying a significant relationship between mineralization stages and patients' age (Page and the calcification stage taking gender and localization of the third molar into consideration. It is possible to estimate chronological age based on Demirjian's stage of a third molar, regardless of gender and location.

  17. Testing teleconnections - chronological uncertainties of independently dated and tuned past climate events (Invited)

    Science.gov (United States)

    Blaauw, M.; Wohlfarth, B.

    2010-12-01

    Multiple fossil proxy archives are often dated by aligning purportedly simultaneous events between data sets. Examples are synchronising peat layers across countries or continents, orbital tuning, and dating cores through aligning proxy features with δ18O series from marine and ice deposits. Any temporal mismatch between multiple sites are then attributed to chronological errors, e.g., changing 14C age offsets, unidentified hiatuses or other mistakes in age-models. However, tuning involves the real danger of erroneously "sucking" separate events into one illusionary event, or vice versa. As an alternative, past climate events can be dated independently (e.g. using 14C dating), while explicitly quantifying their chronological uncertainties. Instead of assuming simultaneous climate events between multiple archives, the age models are kept separate, and the timing of events tested by calculating the probability of simultaneous events within a defined period of time. The method is tested by comparing Dansgaard/Oeschger-like events in two well-dated sites; Les Echets in France and NGRIP in Greenland. Chronological uncertainties are so high that we cannot safely assume that climate events were synchronous between sites at decadal to multi-centennial time scales. Past climate research would profit if tuning procedures would become more quantitative, reliable and objective. Ideally, individual proxy archives should not be tuned, and kept on independent time-scales.

  18. Inferring sources for mercury to inland lakes using sediment chronologies of polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Parsons, Matthew J; Long, David T; Giesy, John P; Kannan, Kurunthachalam

    2014-09-20

    Sediment chronologies from inland lakes suggest the influence of local to sub-regional scale sources for mercury (Hg). However, apportionment of sources for Hg using sediment chronologies is difficult due to the mixing of sources and pathways. Mercury and polycyclic aromatic hydrocarbons (PAH) often share common sources and pathways into the environment. Thus, chronologies of PAHs in dated cores of sediments might be a useful tool to infer sources of Hg. Sediment cores from seven inland lakes of Michigan were collected for measurement of PAHs and Hg and dated by use of (210)Pb. PAH concentrations and ratios of kinetic and thermodynamic PAH compounds were used to infer sources of Hg. Ratios indicate the existence of modern combustion sources to each lake and historic combustion sources to lakes near cement kilns and an iron foundry. Coal combustion sources were identified for two lakes near urban centers. Whereas a petroleum combustion source was identified for a lake that has a coal fired power plant along its shoreline. These results have implications for the cycling of Hg on local to regional scales. PMID:24875801

  19. Lake trout otolith chronologies as multidecadal indicators of high-latitude freshwater ecosystems

    Science.gov (United States)

    Black, B.A.; Von Biela, V.R.; Zimmerman, C.E.; Brown, Randy J.

    2013-01-01

    High-latitude ecosystems are among the most vulnerable to long-term climate change, yet continuous, multidecadal indicators by which to gauge effects on biology are scarce, especially in freshwater environments. To address this issue, dendrochronology (tree-ring analysis) techniques were applied to growth-increment widths in otoliths from lake trout (Salvelinus namaycush) from the Chandler Lake system, Alaska (68.23°N, 152.70°W). All otoliths were collected in 1987 and exhibited highly synchronous patterns in growth-increment width. Increments were dated, the widths were measured, and age-related growth declines were removed using standard dendrochronology techniques. The detrended time series were averaged to generate an annually resolved chronology, which continuously spanned 1964–1984. The chronology positively and linearly correlated with August air temperature over the 22-year interval (p < 0.01), indicating that warmer summers were beneficial for growth, perhaps by increasing fish metabolic rate or lake productivity. Given the broad distribution of lake trout within North America, this study suggests that otolith chronologies could be used to examine responses between freshwater ecosystems and environmental variability across a range of temporal and spatial scales.

  20. Gross Motor Coincidence Timing by Children with Learning Difficulties and Children Matched on Mean Chronological and Mental Age.

    Science.gov (United States)

    Jacklin, Susan M.

    1987-01-01

    This study examines the learning of a gross motor coincidence timing task by children with learning difficulties, compared with that by children of average intelligence of an equivalent chronological age and mental age. Results are discussed. (Author/MT)

  1. Bomb carbon in the yelloweye rockfish, Sebastes ruberrimus, as a chronological benchmark for age validation of commercially important fishes

    OpenAIRE

    Kerr, Lisa A.; Andrews, Allen H.; Frantz, Brian R.; Coale, Kenneth H.; Brown, Thomas A.; Gregor M Cailliet

    2004-01-01

    The overall goals of this study were to (1) establish a chronological benchmark for bomb radiocarbon in the waters of southeast Alaska by determining radiocarbon levels in otoliths of the yelloweye rockfish (Sebastes ruberrimus), for which age was validated, (2) validate the age of quillback rockfish (S. maliger), bocaccio rockfish (S. paucispinis), cowcod (S. levis), and canary rockfish (S. pinniger) using the yelloweye rockfish radiocarbon chronology, (3) provide a basis for future age and ...

  2. IceChrono1: a probabilistic model to compute a common and optimal chronology for several ice cores

    OpenAIRE

    F. Parrenin; Bazin, L.; E. Capron; Landais, A.; B. Lemieux-Dudon; Masson-Delmotte, V.

    2015-01-01

    Polar ice cores provide exceptional archives of past environmental conditions. The dating of ice cores and the estimation of the age-scale uncertainty are essential to interpret the climate and environmental records that they contain. It is, however, a complex problem which involves different methods. Here, we present IceChrono1, a new probabilistic model integrating various sources of chronological information to produce a common and optimized chronology for several ice cor...

  3. Modelling of dead carbon fraction in speleothems: a step towards reliable speleothem 14C-chronologies

    Science.gov (United States)

    Lechleitner, Franziska A.; Jamieson, Robert A.; McIntyre, Cameron; Baldini, Lisa M.; Baldini, James U. L.; Eglinton, Timothy I.

    2015-04-01

    Over the past two decades, speleothems have become one of the most versatile and promising archives for the study of past continental climate. Very precise absolute dating is often possible using the U-Th method, resulting in paleoclimate records of exceptional resolution and accuracy. However, not all speleothems are amenable to this dating method for a variety of reasons (e.g. low U concentrations, high detrital Th etc). This has lead researchers to exclude many otherwise suitable speleothems and cave sites from further investigation. 14C-dating of speleothems has so far not been applicable, due to the 'dead carbon' problem. As drip water percolates through the karst, dissolving CaCO3, a variable amount of 14C-dead carbon is added to the solution. This results in a temporally variable and site-specific reservoir effect, ultimately undermining the development of speleothem 14C -chronologies. However, a number of recent studies have shown a clear link between karst hydrology and associated proxies (e.g., Mg/Ca and δ13C) and this 'dead carbon fraction' (DCF). We take advantage of this relationship to model DCF and its changes using Mg/Ca, δ13C and 14C data from published speleothem records. Using one record for calibration purposes, we build a transfer function for the DCF in relation to δ13C and Mg/Ca, which we then apply to other 14C records. Initial model results are promising; we are able to reconstruct general long-term average DCF within uncertainties of the calculated DCF from the U-Th chronology. Large shifts in DCF related to hydrology are also often detected. In a second step, we apply the model to a speleothem from southern Poland, which so far could not be dated, due to very low U-concentrations. To construct a 14C chronology, the stalagmite was sampled at 5 mm intervals. CaCO3 powders were graphitized and measured by Accelerator Mass Spectrometry (MICADAS) at ETH Zurich. Additional high-resolution (0.1 mm/sample) 14C measurements were performed on

  4. Quality assessment of chronologies in Latin American pollen records: a contribution to centennial to millennial scale studies of environmental change

    Directory of Open Access Journals (Sweden)

    S. G. A. Flantua

    2015-04-01

    Full Text Available The newly updated inventory of the Latin American Pollen Database (LAPD offers an important overview of data available for multi-proxy and multi-site purposes. However, heterogeneous paleoecological databases are not suitable to be integrated without an uncertainty assessment of existing chronologies. Therefore, we collected all chronological control points and age model metadata from the LAPD literature to create a complementary chronological database of 5116 dates from 1097 pollen records. We start with an overview on chronological dating and reporting in Central and South America. Specific problems and recommendations for chronology reporting are discussed. Subsequently, we implement a temporal quality assessment of pollen records from northwest South-America to support research on climate forcers and responses at a centennial-millennial time-scale. New chronologies are generated for 233 pollen records based on updated calibration curves. Different time windows are discussed on sample resolution and temporal uncertainty. Approximately one in four pollen diagrams depicts < 500 years resolution data at the Younger Dryas/Holocene transition. Overall, our analyses suggest that the temporal resolution of multi-site syntheses of late Pleistocene fossil pollen records in the northwest South-America is ca. 240 years, a resolution which allows analysis of ecological responses to centennial-millennial-scale climate change during the last deglaciation.

  5. Developing inorganic carbon-based radiocarbon chronologies for Holocene lake sediments in arid NW China

    Science.gov (United States)

    Zhang, Jiawu; Ma, Xueyang; Qiang, Mingrui; Huang, Xiaozhong; Li, Shuang; Guo, Xiaoyan; Henderson, Andrew C. G.; Holmes, Jonathan A.; Chen, Fahu

    2016-07-01

    Inorganic carbonates are often used to establish radiocarbon (14C) chronologies for lake sediments when terrestrial plant remains (TPR) are rare or when bulk organic matter is insufficient for dating, a problem that is common for many lakes in arid regions. However, the reservoir effect (RE), as well as old carbon contributed from the lakes catchment make it difficult to establish reliable chronologies. Here we present a systematic study of inorganic 14C ages of two lake-sediment sequences, one from a small-enclosed saline lake - Lake Gahai in Qaidam Basin, and the other from a large freshwater lake - Lake Bosten in Xinjiang. Modern dissolved inorganic carbon (DIC) of the lakes, paleo-lake sediments exposed in the catchment, and mollusk shells in core sediments from Lake Gahai were dated to assess the RE and the contribution of pre-aged carbon to the old ages in the cores. We propose a statistical regression to assess more than one RE for the 14C carbonate ages within our sedimentary sequences. Old radiocarbon ages contributed by detrital carbonates were assessed by comparing the ages of mollusk shells with those of carbonates at the same sediment depths. We established the RE of the authigenic component and assessed detrital old carbon contributions to our two sites, and this was used to correct the 14C ages. Based on this approach, we developed age models for both cores, and tested them using 210Pb ages in both cores and TPR-based 14C-ages recovered from Lake Bosten. We further tested our age models by comparing carbonate-based oxygen isotope (δ18O) records from both lakes to an independently-dated regional speleothem δ18O record. Our results suggest if sedimentary sequences are densely dated and the RE and the contribution of old carbon from detrital carbonates can be ascertained, robust chronological frameworks based on carbonate-based 14C determinations can be established.

  6. Volcano-induced regime shifts in millennial tree-ring chronologies from northeastern North America.

    Science.gov (United States)

    Gennaretti, Fabio; Arseneault, Dominique; Nicault, Antoine; Perreault, Luc; Bégin, Yves

    2014-07-15

    Dated records of ice-cap growth from Arctic Canada recently suggested that a succession of strong volcanic eruptions forced an abrupt onset of the Little Ice Age between A.D. 1275 and 1300 [Miller GH, et al. (2012) Geophys Res Lett 39(2):L02708, 10.1029/2011GL050168]. Although this idea is supported by simulation experiments with general circulation models, additional support from field data are limited. In particular, the Northern Hemisphere network of temperature-sensitive millennial tree-ring chronologies, which principally comprises Eurasian sites, suggests that the strongest eruptions only caused cooling episodes lasting less than about 10 y. Here we present a new network of millennial tree-ring chronologies from the taiga of northeastern North America, which fills a wide gap in the network of the Northern Hemisphere's chronologies suitable for temperature reconstructions and supports the hypothesis that volcanoes triggered both the onset and the coldest episode of the Little Ice Age. Following the well-expressed Medieval Climate Anomaly (approximately A.D. 910-1257), which comprised the warmest decades of the last millennium, our tree-ring-based temperature reconstruction displays an abrupt regime shift toward lower average summer temperatures precisely coinciding with a series of 13th century eruptions centered around the 1257 Samalas event and closely preceding ice-cap expansion in Arctic Canada. Furthermore, the successive 1809 (unknown volcano) and 1815 (Tambora) eruptions triggered a subsequent shift to the coldest 40-y period of the last 1100 y. These results confirm that series of large eruptions may cause region-specific regime shifts in the climate system and that the climate of northeastern North America is especially sensitive to volcanic forcing. PMID:24982132

  7. Profiling IgG N-glycans as potential biomarker of chronological and biological ages

    Science.gov (United States)

    Yu, Xinwei; Wang, Youxin; Kristic, Jasminka; Dong, Jing; Chu, Xi; Ge, Siqi; Wang, Hao; Fang, Honghong; Gao, Qing; Liu, Di; Zhao, Zhongyao; Peng, Hongli; Pucic Bakovic, Maja; Wu, Lijuan; Song, Manshu; Rudan, Igor; Campbell, Harry; Lauc, Gordan; Wang, Wei

    2016-01-01

    Abstract As an important post-translation modifying process, glycosylation significantly affects the structure and function of immunoglobulin G (IgG) molecules and is essential in many steps of the inflammatory cascade. Studies have demonstrated the potential of using glycosylation features of IgG as a component of predictive biomarkers for chronological age in several European populations, whereas no study has been reported in Chinese. Herein, we report various patterns of changes in IgG glycosylation associated with age by analyzing IgG glycosylation in 701 community-based Han Chinese (244 males, 457 females; 23–68 years old). Eleven IgG glycans, including FA2B, A2G1, FA2[6]G1, FA2[3]G1, FA2[6]BG1, FA2[3]BG1, A2G2, A2BG2, FA2G2, FA2G2S1, and FA2G2S2, change considerably with age and specific combinations of these glycan features can explain 23.3% to 45.4% of the variance in chronological age in this population. This indicates that these combinations of glycan features provide more predictive information than other single markers of biological age such as telomere length. In addition, the clinical traits such as fasting plasma glucose and aspartate aminotransferase associated with biological age are strongly correlated with the combined glycan features. We conclude that IgG glycosylation appears to correlate with both chronological and biological ages, and thus its possible role in the aging process merits further study. PMID:27428197

  8. Weak chronology protection: the case of NUTty black holes and wormholes

    CERN Document Server

    Clément, Gérard

    2016-01-01

    We investigate the motion of electrically charged test particles in spacetimes with closed timelike curves, a subset of the black hole or wormhole Reissner-Nordstr\\"om-NUT spacetimes without periodic identification of time. We show that, while in the wormhole case there are closed worldlines inside a potential well, the wordlines of initially distant charged observers moving under the action of the Lorentz force can never close or self-intersect. This means that for these observers causality is preserved, which is an instance of our weak chronology protection criterion.

  9. Walter Odington's De etate mundi and the Pursuit of a Scientific Chronology in Medieval England.

    Science.gov (United States)

    Nothaft, Carl Philipp

    2016-01-01

    This article deals with a forgotten treatise on the age of the world, written between 1308 and 1316 by Walter Odington, a monk of Evesham Abbey, otherwise known for his writings on alchemy and music theory. By tracing the sources and rationale behind Odington's arguments and comparing them with those of other medieval authors, the article attempts to shed new light on the state of chronological scholarship in England in the eleventh to fourteenth centuries, when astronomical and astrological methods were freely used to supplement or replace scriptural interpretation, yielding creative and unexpected results. PMID:27320253

  10. [Taking into account both chronology and duration of events is crucial in the medical interview].

    Science.gov (United States)

    Scheen, A J

    2016-03-01

    Medical history taking represents a key step in the diagnostic approach. A structured interview with a special attention to the chronology of events is mandatory. The medical student often fails to use the information on time in an optimal way. The aim of this article is to draw the attention on a few key elements, especially the age of the patient, the duration of symptoms, the time of occurrence of complaints within the 24h period and, finally, how to interpret the simultaneous or sequential occurrence of two (or more) events.

  11. Chronological age and breed-type effects on carcass characteristics and palatability of bull beef.

    Science.gov (United States)

    Riley, R R; Smith, G C; Cross, H R; Savell, J W; Long, C R; Cartwright, T C

    1986-01-01

    Bulls (n = 115) of four slaughter ages (9, 12, 15 or 18 months) and of 15 genotypes were studied. In this analysis, each bullock was assigned to one of four breed groups-British and British crosses, Brahman and Brahman crosses. Jersey and Jersey crosses or Holstein and Holstein crosses. Slaughter age had an (P Brahman-type bulls had higher shear force values (P Brahman-type carcasses were assigned the lowest numerical ratings for juiciness. Breed-type had a greater effect on tenderness of bull beef than did chronological age.

  12. Pathologic diagnosis of malignant mesothelioma: chronological prospect and advent of recommendations and guidelines

    Directory of Open Access Journals (Sweden)

    Valeria Ascoli

    2015-03-01

    Full Text Available Malignant mesothelioma (MM is rare and difficult to diagnose. Its identification depends upon pathological investigation (cyto-histological assessment and immunohistochemistry supported by clinical and radiological evidence. In the last decade, the standardization of diagnostic methods has become a major focus of debate among pathologists and clinicians. This has led to the writing of guidelines and recommendation for the diagnosis to achieve the goal of a standard diagnosis. In this article, a chronological view relating to the pathological diagnosis of MM is presented together with a review of guidelines and recommendations.

  13. Paleogene geology and chronology of southwestern Umnak Island, Aleutian Islands, Alaska ( USA).

    Science.gov (United States)

    McLean, H.; Hein, J.R.

    1984-01-01

    A slightly deformed marine sedimentary sequence reflecting volcanic arc sedimentation from late Eocene to early Oligocene is intruded by hypabyssal quartz diorite sills and small plutons with apparent ages of about 30 Ma, ie, middle Oligocene. Chemical data from igneous rocks exhibit calc-alkaline and tholeiitic volcanic arc differentiation trends. The fossil ages and radiometric dates from SW Umnak Island are similar to those reported from other central and E Aleutian islands, and indicate uniformity in the chronology and tectonic development of the archipelago during the Paleogene. Paleomagnetic data suggest possible northward movement but remain equivocal and more work is indicated. -after Authors

  14. A complete chronological bibliography of the journal 'Research on Language and Social Interaction', 1987-2014

    DEFF Research Database (Denmark)

    Nevile, Maurice Richard

    2015-01-01

    This list presents, in chronological order, all items published in the journal ROLSI. The list makes it easier to find specific items, or to track and search for authors, analytic interests and phenomena, settings and situations, or data languages, etc. The list begins at 1987, when the journal...... and lost typographical detail), removed excess information, and re-formatted and tidied for consistency. The aim was that entries here match the content and formatting of the actual published papers, although I used consistent capitalisation across the list. I also more clearly indicated some Special...

  15. Wormhole spacetimes, CTCs and chronology protection in a dc-SQUID array

    CERN Document Server

    Sabín, Carlos

    2016-01-01

    We present an analog quantum simulator of spacetimes containing traversable wormholes. A suitable spatial dependence in the external bias of a dc-SQUID array mimics the propagation of light in a 1D wormhole background. The impedance of the array places severe limitations on the type of spacetime that we are able to implement. However, we find that wormhole throat radius in the sub-mm range are achievable. We show how to modify this spacetime in order to allow the existence of closed timelike curves. The quantum fluctuations of the phase associated to the finite array impedance might be seen as an analogue of Hawking's chronology protection mechanism.

  16. The EDC3 chronology for the EPICA Dome C ice core

    OpenAIRE

    F. Parrenin; Barnola, J.-M.; Beer, J.; T. Blunier; Castellano, E.; Chappellaz, J.; Dreyfus, G.; Fischer, H.; Fujita, S.; J. Jouzel; K. Kawamura; B. Lemieux-Dudon; Loulergue, L.; Masson-Delmotte, V.; Narcisi, B.

    2007-01-01

    The EPICA (European Project for Ice Coring in Antarctica) Dome C drilling in East Antarctica has now been completed to a depth of 3260 m, at only a few meters above bedrock. Here we present the new EDC3 chronology, which is based on the use of 1) a snow accumulation and mechanical flow model, and 2) a set of independent age markers along the core. These are obtained by pattern matching of recorded parameters to either absolutely dated paleoclimatic records, or to insolation variations. We sho...

  17. The EDC3 chronology for the EPICA Dome C ice core

    OpenAIRE

    F. Parrenin; Barnola, J.-M.; Beer, J.; T. Blunier; Castellano, E.; Chappellaz, J.; Dreyfus, G.; Fischer, H.; Fujita, S.; J. Jouzel; K. Kawamura; B. Lemieux-Dudon; Loulergue, L.; Masson-Delmotte, V.; Narcisi, B.

    2007-01-01

    The EPICA (European Project for Ice Coring in Antarctica) Dome C drilling in East Antarctica has now been completed to a depth of 3260 m, at only a few meters above bedrock. Here we present the new EDC3 chronology, which is based on the use of 1) a snow accumulation and mechanical flow model, and 2) a set of independent age markers along the core. These are obtained by pattern matching of recorded parameters to either absolutely dated paleoclimatic records, or to insolation ...

  18. Primary results of pottery analyses from al-Khidr (general typology and chronology)

    OpenAIRE

    Benediková, Lucia; Ďuriš, Jozef

    2014-01-01

    Pottery presented in this paper comes from the research of al-Khidr site on Failaka island, State of Kuwait, that was excavated by the Kuwaiti-Slovak Archaeological Mission in 2004-2008. It offers a basic typological and chronological ordering of pottery assemblage retrieved during the field works in 2004 and 2006 seasons. Although they represent a small portion of the whole pottery collection from al-Khidr, the ceramics from 2004 and 2006 enable an overview of all the basic stratigraphic hor...

  19. 14C Chronological Framework in the "Xia-Shang-Zhou Chronology Project"%夏商周断代工程中的碳十四年代框架

    Institute of Scientific and Technical Information of China (English)

    仇士华; 蔡莲珍

    2001-01-01

    The reliable dates Chinese historians recorded begin only from 841 BC. For the prehistoric chronology, radiocarbon dating has been an important method; but for historic times, it is difficult to determine the dates of objects and events. Recently, the technique of radiocarbon dating has been greatly improved by raising its precision and by adopting the high-precision 14C-dendrochronology curve and AMS 14C method, owing to which as well as the progress of archaeology it is hopeful to establish today the framework of Xia-Shang-Zhou chronology. By using a liquid scintillation counter with the measuring error less than 3‰ for conventional radiocarbon dating and wiggle-matching with calibration-curve, our dating group has achieved gratifying results for the chronological study of the Three Dynasties. The basis of the chronological framework is estabilished through radiocarbon dating of the series of samples excavated from many well-known sites. Finally, the radiocarbon chronological framework and corresponding table of the Xia, Shang and Zhou dynasties are acquired through synthetical study.

  20. Towards an absolute chronology for the Aegean iron age: new radiocarbon dates from Lefkandi, Kalapodi and Corinth.

    Directory of Open Access Journals (Sweden)

    Michael B Toffolo

    Full Text Available The relative chronology of the Aegean Iron Age is robust. It is based on minute stylistic changes in the Submycenaean, Protogeometric and Geometric styles and their sub-phases. Yet, the absolute chronology of the time-span between the final stages of Late Helladic IIIC in the late second millennium BCE and the archaic colonization of Italy and Sicily toward the end of the 8(th century BCE lacks archaeological contexts that can be directly related to events carrying absolute dates mentioned in Egyptian/Near Eastern historical sources, or to well-dated Egyptian/Near Eastern rulers. The small number of radiocarbon dates available for this time span is not sufficient to establish an absolute chronological sequence. Here we present a new set of short-lived radiocarbon dates from the sites of Lefkandi, Kalapodi and Corinth in Greece. We focus on the crucial transition from the Submycenaean to the Protogeometric periods. This transition is placed in the late 11(th century BCE according to the Conventional Aegean Chronology and in the late 12(th century BCE according to the High Aegean Chronology. Our results place it in the second half of the 11(th century BCE.

  1. Towards an absolute chronology for the Aegean iron age: new radiocarbon dates from Lefkandi, Kalapodi and Corinth.

    Science.gov (United States)

    Toffolo, Michael B; Fantalkin, Alexander; Lemos, Irene S; Felsch, Rainer C S; Niemeier, Wolf-Dietrich; Sanders, Guy D R; Finkelstein, Israel; Boaretto, Elisabetta

    2013-01-01

    The relative chronology of the Aegean Iron Age is robust. It is based on minute stylistic changes in the Submycenaean, Protogeometric and Geometric styles and their sub-phases. Yet, the absolute chronology of the time-span between the final stages of Late Helladic IIIC in the late second millennium BCE and the archaic colonization of Italy and Sicily toward the end of the 8(th) century BCE lacks archaeological contexts that can be directly related to events carrying absolute dates mentioned in Egyptian/Near Eastern historical sources, or to well-dated Egyptian/Near Eastern rulers. The small number of radiocarbon dates available for this time span is not sufficient to establish an absolute chronological sequence. Here we present a new set of short-lived radiocarbon dates from the sites of Lefkandi, Kalapodi and Corinth in Greece. We focus on the crucial transition from the Submycenaean to the Protogeometric periods. This transition is placed in the late 11(th) century BCE according to the Conventional Aegean Chronology and in the late 12(th) century BCE according to the High Aegean Chronology. Our results place it in the second half of the 11(th) century BCE. PMID:24386150

  2. Spatial variability in growth-increment chronologies of long-lived freshwater mussels: Implications for climate impacts and reconstructions

    Science.gov (United States)

    Black, Bryan A.; Dunham, Jason B.; Blundon, Brett W.; Raggon, Mark F.; Zima, Daniela

    2010-01-01

    Estimates of historical variability in river ecosystems are often lacking, but long-lived freshwater mussels could provide unique opportunities to understand past conditions in these environments. We applied dendrochronology techniques to quantify historical variability in growth-increment widths in valves (shells) of western pearlshell freshwater mussels (Margaritifera falcata). A total of 3 growth-increment chronologies, spanning 19 to 26 y in length, were developed. Growth was highly synchronous among individuals within each site, and to a lesser extent, chronologies were synchronous among sites. All 3 chronologies negatively related to instrumental records of stream discharge, while correlations with measures of water temperature were consistently positive but weaker. A reconstruction of stream discharge was performed using linear regressions based on a mussel growth chronology and the regional Palmer Drought Severity Index (PDSI). Models based on mussel growth and PDSI yielded similar coefficients of prediction (R2Pred) of 0.73 and 0.77, respectively, for predicting out-ofsample observations. From an ecological perspective, we found that mussel chronologies provided a rich source of information for understanding climate impacts. Responses of mussels to changes in climate and stream ecosystems can be very site- and process-specific, underscoring the complex nature of biotic responses to climate change and the need to understand both regional and local processes in projecting climate impacts on freshwater species.

  3. Availability of Amino Acids Extends Chronological Lifespan by Suppressing Hyper-Acidification of the Environment in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Yo Maruyama

    Full Text Available The chronological lifespan of Saccharomyces cerevisiae represents the duration of cell survival in the postdiauxic and stationary phases. Using a prototrophic strain derived from the standard auxotrophic laboratory strain BY4742, we showed that supplementation of non-essential amino acids to a synthetic defined (SD medium increases maximal cell growth and extends the chronological lifespan. The positive effects of amino acids can be reproduced by modulating the medium pH, indicating that amino acids contribute to chronological longevity in a cell-extrinsic manner by alleviating medium acidification. In addition, we showed that the amino acid-mediated effects on extension of chronological longevity are independent of those achieved through a reduction in the TORC1 pathway, which is mediated in a cell-intrinsic manner. Since previous studies showed that extracellular acidification causes mitochondrial dysfunction and leads to cell death, our results provide a path to premature chronological aging caused by differences in available nitrogen sources. Moreover, acidification of culture medium is generally associated with culture duration and cell density; thus, further studies are required on cell physiology of auxotrophic yeast strains during the stationary phase because an insufficient supply of essential amino acids may cause alterations in environmental conditions.

  4. A high-precision chronology for the rapid extinction of New Zealand moa (Aves, Dinornithiformes)

    Science.gov (United States)

    Perry, George L. W.; Wheeler, Andrew B.; Wood, Jamie R.; Wilmshurst, Janet M.

    2014-12-01

    Megafaunal extinction followed the prehistoric human settlement of islands across the globe, but the exact duration and dynamics of the extinction processes are difficult to determine. The New Zealand moa (Aves, Dinornithiformes) are a prime example, where, despite an extensive fossil and archaeological record, debate continues about their extinction chronology and how extinction timings varied among regions and species. We apply probabilistic sightings methods to 111 high-quality radiocarbon dates (from a pool of 653 dates) on moa remains from natural and archaeological sites to provide a high-resolution spatio-temporal chronology of moa extinction. We interpret this alongside an estimated time for the onset of hunting pressure, obtained by applying the same methods to the most reliable proxies for initial human settlement of New Zealand: coprolites of and seeds gnawed by the commensal Pacific rat (Rattus exulans). By comparing local and national extinction times, we discriminate between the point at which hunting stopped (economic extinction) and the total extinction of moa (ca 150 and 200 years after settlement, respectively). Extinction occurred contemporaneously at sites separated by hundreds of kilometres. There was little difference between the extinction times of the smallest (20-50 kg) and largest (200+ kg) moa species. Our results demonstrate how rapidly megafauna were exterminated from even large, topographically- and ecologically-diverse islands such as New Zealand, and highlight the fragility of such ecosystems in the face of human impacts.

  5. Chronologically sampled flight feathers permits recognition of individual molt-migrants due to varying protein sources

    Directory of Open Access Journals (Sweden)

    Sievert Rohwer

    2015-01-01

    Full Text Available This is a proof of concept paper based on chronological samples of growing feathers from geese thought to be molt-migrants. When molt-migrant birds initiate molt shortly after migrating to a new isoscape, isotope values measured along the length of their feathers should change continuously. To assess long-term changes and daily cycling in δ15N and δ13C values, we serially sampled a growing primary from three presumed molt-migrant geese. Two showed changing δ15N signatures along the length of their growing primary, indicating they were molt-migrants, while the third, presumably a resident, showed no change. We then resampled these feathers at closer intervals for evidence of the predicted diel cycle in the use of exogenous and endogenous protein for feather growth, generated by the diel feeding cycle of these geese. As predicted, a periodicity of ca. 24 h in δ15N values was found along the primary of the two equilibrating geese, but not in the other goose that was probably a resident. Our results demonstrate that chronological sampling along the length of individual primaries holds great potential for identifying individuals that are molt-migrants.

  6. Chronological and subjective age differences in flourishing mental health and major depressive episode.

    Science.gov (United States)

    Keyes, Corey L M; Westerhof, Gerben J

    2012-01-01

    Mental health is more than the absence of psychopathology, but few studies use positive mental health along with a measure of past year major depressive episode (MDE). This study addresses this gap by investigating the association of MDE and flourishing mental health (FMH) with chronological age and subjective (felt and ideal) age. Data are from the Midlife in the United States random digit dialing sample of adults ages 25 to 74, collected in 1995 (n = 3032). Rates of MDE were lowest, and FMH highest, among the three oldest age cohorts (45-54, 55-64, 65-74 years). Subjective age was linked with chronological age; with age, adults tend to feel younger, and want to be an age that is younger, than their actual age. As predicted by the model of subjective age as an adaptive strategy, feeling younger was related to a lower risk of MDE and a higher risk of FMH. However, wanting to be younger was related to a lower risk of FMH and unrelated to MDE. PMID:21780972

  7. Mineralization of mandibular third molars can estimate chronological age--Brazilian indices.

    Science.gov (United States)

    de Oliveira, Fernando Toledo; Capelozza, Ana Lúcia Álvares; Lauris, José Roberto Pereira; de Bullen, Izabel Regina Fischer Rubira

    2012-06-10

    Forensic age estimation is an important element of anthropological research, as it produces one of the primary sources of data that researchers use to establish the identity of a person living or the identity of unknown bodily remains. The aim of this study was to determine if the chronology of third molar mineralization could be an accurate indicator of estimated age in a sample Brazilian population. If so, mineralization could determine the probability of an individual being 18 years or older. The study evaluated 407 panoramic radiographs of males and females from the past 5 years in order to assess the mineralization status of the mandibular third molars. The evaluation was carried out using an adaptation of Demirjian's system. The results indicated a strong correlation between chronological age and the mineralization of the mandibular third molars. The results indicated that modern Brazilian generation tends to demonstrate an earlier mandibular third molar mineralization than older Brazilian generation and people of other nationalities. Males reached developmental stages slightly earlier than females, but statistically significant differences between the sex were not found. The probability that an individual with third molar mineralization stage H had reached an age of 18 years or older was 96.8-98.6% for males and females, respectively.

  8. The chronological age estimation of third molar mineralization of Han population in southwestern China.

    Science.gov (United States)

    Qing, Maofeng; Qiu, Lihua; Gao, Zhi; Bhandari, Kishor

    2014-05-01

    The purpose of the study was to estimate the chronology of third molar mineralization in Han population of southwestern China and find its unique characteristics so that it would provide a reference in several legal cases like forensic age estimation. The study used Demirjian's staging method to study 2192 orthopantomograms of 984 male and 1208 female subjects aged between 8 and 25 years. The statistical data was analyzed by Student's t test and ANOVA. The conclusions of the study are: (1) The chronological mineralization age of third molars of Han population in Southwestern China is similar to the Turkish and the Japanese, was earlier than the Austrian and Han of South China, but later than the Spanish. (2) The mineralization timing of the third molars between two sides in maxilla or mandible has no significant differences in the same gender group. (3) There is no significant difference in mineralization of third molars between male and female, except for tooth 48 in Demirjian's stage E. (4) The mineralization of third molar in maxilla is earlier than mandible.

  9. The chronology of second molar development in Brazilians and its application to forensic age estimation

    International Nuclear Information System (INIS)

    This study investigated the possible correlation between the mineralization of the second molars and the chronological age of a sample population of the state of Paraiba, Brazil. One thousand eight hundred fifty-four digitized panoramic images using a scanner of a private dental radiology service were obtained in six months. Of these, 457 were selected from patients aged 4.6 to 16 years who met certain criteria. The images were assessed twice by a radiologist with 5 years experience. A minimum interval of 30 days between the evaluations of the same patient was established. To analyze the relationship between chronological age, calcification level proposed by Demirjian et al in 1973, gender, and tooth, a multiple linear regression model was adjusted, taking age as the response variable (p<0.05). The gender and calcification level were significantly correlated with the age of the patients (p<0.05). There was a significant difference between the average age of the patients' upper teeth compared to the lower ones in both genders (p<0.05). The dental development occurred earlier in female individuals than in male ones, and there was no significant difference between the right and left second permanent molars. It was observed that ethnic variables are related to certain parameters of age and sex identification in the Brazilian population, providing important information for forensic evaluations.

  10. The chronology of second molar development in Brazilians and its application to forensic age estimation

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Manuella; Santos Carneiro; Beltraeo, Rejane Targino; Beltraeo, Ricardo Villar [School of Dentistry, Federal University of Paraiba, Joaeo Pessoa (Brazil); Pontual, Andrea dos Anjos [Pernambuco Dental School, Pernambuco University-UPE, Camaragibe (Brazil); Pontual, Maria Luiza dos Anjos [Federal University of Pernambuco, Recife (Brazil)

    2013-03-15

    This study investigated the possible correlation between the mineralization of the second molars and the chronological age of a sample population of the state of Paraiba, Brazil. One thousand eight hundred fifty-four digitized panoramic images using a scanner of a private dental radiology service were obtained in six months. Of these, 457 were selected from patients aged 4.6 to 16 years who met certain criteria. The images were assessed twice by a radiologist with 5 years experience. A minimum interval of 30 days between the evaluations of the same patient was established. To analyze the relationship between chronological age, calcification level proposed by Demirjian et al in 1973, gender, and tooth, a multiple linear regression model was adjusted, taking age as the response variable (p<0.05). The gender and calcification level were significantly correlated with the age of the patients (p<0.05). There was a significant difference between the average age of the patients' upper teeth compared to the lower ones in both genders (p<0.05). The dental development occurred earlier in female individuals than in male ones, and there was no significant difference between the right and left second permanent molars. It was observed that ethnic variables are related to certain parameters of age and sex identification in the Brazilian population, providing important information for forensic evaluations.

  11. Chronological age and breed-type effects on carcass characteristics and palatability of bull beef.

    Science.gov (United States)

    Riley, R R; Smith, G C; Cross, H R; Savell, J W; Long, C R; Cartwright, T C

    1986-01-01

    Bulls (n = 115) of four slaughter ages (9, 12, 15 or 18 months) and of 15 genotypes were studied. In this analysis, each bullock was assigned to one of four breed groups-British and British crosses, Brahman and Brahman crosses. Jersey and Jersey crosses or Holstein and Holstein crosses. Slaughter age had an (P carcasses with the thickest subcutaneous fat, the highest marbling score and the highest USDA quality grade while Jersey and Jersey cross bullocks yielded carcasses with the lowest weight, smallest longissimus muscle area and the lowest USDA quality grade of the four breed-type groups. Increases in chronological age (from 9 to 18 months) were generally associated with a decrease in USDA maturity score, and increases in marbling score, USDA quality grade, longissimus muscle area, subcutaneous fat thickness and USDA yield grade. Shear force values decreased as bulls matured from 9 to 18 months of age. The meat from Brahman-type bulls had higher shear force values (P carcasses received the highest numerical ratings for sustained juiciness and flavor while steaks from the Brahman-type carcasses were assigned the lowest numerical ratings for juiciness. Breed-type had a greater effect on tenderness of bull beef than did chronological age.

  12. New radiocarbon chronology of a late Holocene landslide event in the Mont Blanc massif, Italy

    Science.gov (United States)

    Hajdas, Irka; Sojc, Ursula; Ivy-Ochs, Susan; Akçar, Naki; Deline, Philip

    2016-04-01

    The Ferret valley Arp Nouva peat bog located in the Mont Blanc massif was critically evaluated since previously published radiocarbon dates have led to controversial conclusions on the formation of the swamp. Radiocarbon dating of roots from three pits of up to 1 m depth was applied to discuss the question whether the historical documented rock avalanche occurring in AD 1717 overran the peat bog or formed it at a later stage. Our results indicate that the rock avalanche formed the Arp Nouva peat bog by downstream blockage of the Bellecombe torrent. Furthermore, careful sample preparation with consequent separation of roots from the bulk peat sample provides possible explanation for the too old 14C ages of bulk peat samples dated previously (Deline and Kirkbride, 2009 and references therein). This work demonstrates that a combined geomorphological and geochronological approach is the most reliable way to reconstruct landscape evolution, especially in light of apparent chronological problems. The key to successful 14C dating is a careful sample selection and the identification of material that might be not ideal for chronological reconstructions. References Deline, Philip, and Martin P. Kirkbride. "Rock avalanches on a glacier and morainic complex in Haut Val Ferret (Mont Blanc Massif, Italy)".Geomorphology 103 (2009): 80-92.

  13. Chronology, Narrative, and Founding Acts: Between a Transcendental Rock and a Decisionist Hard Place

    Directory of Open Access Journals (Sweden)

    Jack Reilly

    2015-06-01

    Full Text Available In attempting to represent political transformations, we often encounter a moment that seems to resist narrativisation, a moment of obstinate inconsistency which various theoretical, historical and fictional accounts cannot properly absorb except by way of indicating the parameters of a rupture. Here, I present a position which views these unrepresentable moments as structurally necessary features of revolutionary events. It is not simply that, at such historical junctures, we are faced with an abundance of information and that the unrepresentability or narrative deficit is the consequence of this surplus; on the contrary, the founding act that accompanies any radical transformation necessarily involves a certain temporal contraction. To the extent that narrative relies on a linear chronology, it fails to capture this moment of contraction. Indeed, this is why works of political philosophy associated with a founding contract (for example Hobbes’s Leviathan and Rousseau’s Social Contract cannot fully suppress the moment of circularity in which the rhythm of chronological time skips a beat and, to paraphrase Rousseau, one requires an effect to perform the function associated with its own cause. If the moment of founding can be represented at all, it is only by way of paradox and metaphor.

  14. Potential radiocarbon chronology tool using archaeal tetraether lipids for the western Arctic Ocean sediment

    Science.gov (United States)

    Uchida, M.; Kondo, M.; Utsumi, M.; Shibata, Y.

    2011-12-01

    The Arctic Ocean plays a major role in global climate changes by changing global energy balance through ice-albedo feedback and by affecting the oceanic thermohaline circulation through the water exchange with the Atlantic and Pacific Ocean. For future prediction of those changes in Arctic Ocean it is necessary to reconstruct details of past climate history with accurate age model. However, it is not easy to make age model of sediment cores covering late Pleistocene-Holocene transition including global abrupt climate change because preservation of carbonate fossil such as planktonic foraminifera is very limited. In the glacial time, foraminifera is almost barren. Thus, so far climate history in the Arctic Ocean environment is poorly understood. For these reasons, we are looking for alternative chronological target instead of foraminifera. In this study, radiocarbon contents of archaeal glycerol dibiphytanyl glycerol tetraether lipids (GDGTs) from Arctic surface sediments, which is also used for paleothermometry, were measured and compared with those of dissolved inorganic carbon (DIC) of sea water, planktonic and benthic foraminifera, shell, and bulk organic matter in the same horizons. We will discuss potential as chronology using the GDGTs and carbon sources of these compounds.

  15. The Pranemuru project and the radiocarbon chronology of the Sardinian Bronze Age

    Directory of Open Access Journals (Sweden)

    Rubinos, Antonio

    2003-12-01

    Full Text Available New C-14 data collected by a Spanish team working in the Sardinian Pranemuru area, allow usthe possibility of revising the C-14 Chronology for the Nuragic Bronze Age and discussing the reliability of some of the dates, as well as the way they have been published, and their matching with the new official chronology for the Sardinian Bronze and Iron Ages, built on Dendro and C14 sequences for the Italian Peninsula.

    La obtención por parte del Proyecto Pranemuru de cerca de una veintena de dataciones radiocarbónicas para una microregión en época nurágica, de las que aquí se recogen discuten catorce, abre la posibilidad de revisar la cronología de la Edad del Bronce en Cerdeña, a la luz de las dataciones recogidas desde los años 90 por Trump (1990 y Tykot (1994 y, más recientemente, por Webster (2001, discutir la validez de las fechas en función de los criterios de recogida de muestra, contexto arqueológico, desviación estándar y forma en que ha sido publicada, así como contrastarla con la cronología propuesta recientemente para la Protohistoria sarda, de acuerdo con la Dendrocronología y Cronología Radiocarbónica para la Italia peninsular (Lo Schiavo 2002.

  16. Chronology of Holocene lacustrine sediments in Co Ngoin, central Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    WU; Yanhong; WANG; Sumin; HOU; Xinhua

    2006-01-01

    Chronology is the basis for using lacustrine sediments to reconstruct the history of environmental change. Radioactive-nuclides such as 14C, 210Pb and 137Cs dating are mainly used to establish the chronology for recent several ten thousand years. Because of being mixed with "dead carbon", the measured 14C age is always older than the actual age which is recognized as "reservoir effect". Cs is a kind of active metal element, and easy to migrate vertically in the sediment that leads to the error of the time marker. 210Pb dating should make sure to select CIC model or CRS model. On the Tibetan Plateau, most of the lakes are alkaline closed lake where Cs is more moveable in the sediment and the reservoir effect caused by "dead carbon" on 14C dating is stronger. Based on the analysis on results of 14C, 210Pb and 137Cs of the lacustrine sediments from Co Ngoin, central Tibetan Plateau, we use the simple regression method to re-calculate the 14C calendar ages, and establish the time sequence for cores CE-1 and CE-2 with result of 210Pb CRS model for the upper 35 cm and recalculated 14C calendar age for sediments bellow 35 cm. Since 1400 cal. a BP, sedimentation interrupted for more than 1000 years. According to this time sequence, variations of environmental proxies confidently reflect the major climatic events in Holocene.

  17. Yeast MRX deletions have short chronological life span and more triacylglycerols.

    Science.gov (United States)

    Kanagavijayan, Dhanabalan; Rajasekharan, Ram; Srinivasan, Malathi

    2016-02-01

    Saccharomyces cerevisiae is an excellent model organism for lipid research. Here, we have used yeast haploid RAdiation Damage (RAD) deletion strains to study life span and lipid storage patterns. RAD genes are mainly involved in DNA repair mechanism and hence, their deletions have resulted in shorter life span. Viable RAD mutants were screened for non-polar lipid content, and some of the mutants showed significantly high amounts of triacylglycerol (TAG) and steryl ester, besides short chronological life span. Among these, RAD50, MRE11 and XRS2 form a complex, MRX that is involved in homologous recombination that showed an increase in the amount of TAG. Microarray data of single MRX deletions revealed that besides DNA damage signature genes, lipid metabolism genes are also differentially expressed. Lipid biosynthetic genes (LPP1, SLC1) were upregulated and lipid hydrolytic gene (TGL3) was downregulated. We observed that rad50Δ, mre11Δ, xrs2Δ and mrxΔ strains have high number of lipid droplets (LDs) with fragmented mitochondria. These mutants have a short chronological life span compared to wild type. Aged wild-type cells also accumulated TAG with LDs of ∼2.0 μm in diameter. These results suggest that TAG accumulation and big size LDs could be possible markers for premature or normal aging. PMID:26678749

  18. A detailed post-IR IRSL chronology for the last interglacial soil at the Jingbian loess site (northern China)

    DEFF Research Database (Denmark)

    Buylaert, Jan-Pieter; Yeo, Eun-Young; Thiel, Christine;

    2015-01-01

    The chronology of dust deposition and climate during the last interglacial is poorly known on the Chinese Loess Plateau. Here, 51 samples were taken from the ~5 m S1 palaeosol (MIS5) at the desert marginal Jingbian site to develop what is currently the most detailed S1 chronology on the Plateau...... for S1 is ~150 g m-2 a-1, considerably higher than at many other sites but within the overall range of Loess Plateau estimates. The remarkably stable sediment accumulation at the site contrasts with a more complex record of environmental and monsoonal change recorded in grain-size and magnetic...

  19. Chronological age estimation of third molar mineralization of Han in southern China.

    Science.gov (United States)

    Zeng, Dong Lin; Wu, Zhi Ling; Cui, Min Yi

    2010-03-01

    In order to study the chronology of age of third molar mineralization of Han in southern China, Demirjian staging method was used to determine the stage of four third molars (18, 28, 38, 48) mineralization in 3,100 Han in southern China aged 4.1-26.9 years based on radiological evidence from digital orthopantomograms. The mean age of the 3,100 patients was 15.96 +/- 4.73 years, including 1,200 male (mean age, 15.32 +/- 4.62) and 1,900 female (mean age, 16.35 +/- 4.76). Results show that there was no significant difference in mineralization between 18 and 28 and 38 and 48 of male or female. However, significant difference was observed between 28 and 38 of female at stage C; 28 was 0.25 years earlier than 38. In male, at stage G, 38 was 0.61 years earlier than 28, and 48 was 0.62 years earlier than 18. At stages D, E, F, G, and H, male 48 was 0.34, 0.66, 0.72, 1.34, and 0.76 years earlier than that of female, respectively. At stages A, D, E, F, G, and H, male 38 was 0.73, 0.26, 0.56, 0.91, 1.29, and 0.70 years earlier than that of female, respectively. At stages B, E, F, G, and H, the mineralization mean age of male 18 was 0.54, 0.50, 0.76, 0.92, and 0.58 years earlier than that of female, respectively. At stages E, F, G, and H, the mineralization mean age of male 28 was 0.51, 0.76, 0.92, and 0.49 years earlier than that of female, respectively. After reviewing the literature, the chronological mineralization age of 48, at stages D to G, of Han in southern China was 1 to 4.6 years earlier than that of Japanese and 1 to 3 years earlier than that of German. The mean age at stage H of 48 of Han in southern China was similar to Turkish, Black African, Japanese, and German, but was later than Spanish. Finally, the conclusions are: (1) in the same gender group of Han in southern China, the mineralization ages between two sides in upper or lower jaw are very similar, and (2) the chronology mean age and complete time of third molar mineralization of male were earlier than

  20. Mid-Late Pleistocene OSL chronology in western Amazonia and implications for the transcontinental Amazon pathway

    Science.gov (United States)

    Rossetti, Dilce F.; Cohen, Marcelo C. L.; Tatumi, Sonia H.; Sawakuchi, André O.; Cremon, Édipo H.; Mittani, Juan C. R.; Bertani, Thiago C.; Munita, Casimiro J. A. S.; Tudela, Diego R. G.; Yee, Márcio; Moya, Gabriela

    2015-12-01

    The origin of the transcontinental Amazon drainage system remains unrevealed. Sedimentary deposits formed from the Neogene in the Amazonas and Solimões Basins constitute natural archives for reconstructing this event in space and time. However, paleoenvironmental and chronological analyses focusing on these deposits, or even their basic mapping, are still scarce to allow such investigation. In this context, primary interests are fluvial strata related to the lithostratigraphic Içá Formation, mapped over a widespread area in western Amazonian lowlands. Although long regarded as Plio-Pleistocene in age, this unit has not yet been dated and its overall depositional setting remains largely undescribed. The main goal of the present work is to contribute for improving facies analysis and chronology of these deposits, approaching an area in southwestern Amazonia and another in northern Amazonia, which are located more than 1000 km apart. Despite this great distance, the sedimentological and chronological characteristics of deposits from these two areas are analogous. Hence, facies analysis revealed paleoenvironments including active channel, abandoned channel, point bar, crevasse splay and floodplain, which are altogether compatible with meandering fluvial systems. Similarly, optically stimulated luminescence (OSL) dating revealed thirty three ages ranging from 65.4 ± 16.9 to 219.6 ± 25.1 ky (in addition to three outliners of 54.0 ± 7.6, 337.3 ± 36.9 and 346.6 ± 48.6 ky), and nine 97.1 ± 9.9 to 254.8 ± 23.8 ky for the areas in southwestern and northern Amazonia, respectively. These data lead to establish that deposits mapped as Içá Formation over a vast area of western Brazilian Amazonia have a Mid-Late Pleistocene age, rather than the previously inferred Plio-Pleistocene age. It follows that if Plio-Pleistocene deposits exist in this region they remain to be dated and must be restricted to a narrow belt in western Amazonia, as well as isolated occurrences

  1. History of Shock Waves, Explosions and Impact A Chronological and Biographical Reference

    CERN Document Server

    Krehl, Peter O. K

    2009-01-01

    This unique and encyclopedic reference work charts the evolution of the physics of shock waves and detonations from the earliest investigations into percussion and impact phenomena right up to the most recent groundbreaking research in the field. The history of this long and complex process is first reviewed in a general survey that encompasses everything from the earliest observations and interpretations of puzzling high-rate dynamic phenomena associated with natural and man-made explosions to a discussion of the merits of modern numerical computer simulations. The subject is then treated in more detail and in chronological order in the central section of the book, while also being richly illustrated in form of a picture gallery. The bibliographic index provides 122 short biographies of eminent researchers who have contributed to the field. Further references for biographical sources are given, and both name and subject indices (with over 4500 and 2700 entries, respectively) are provided. "This book is of tr...

  2. From wormhole to time machine: Remarks on Hawking's chronology protection conjecture

    International Nuclear Information System (INIS)

    The recent interest in ''time machines'' has been largely fueled by the apparent ease with which such systems may be formed in general relativity, given relatively benign initial conditions such as the existence of traversable wormholes or of infinite cosmic strings. This rather disturbing state of affairs has led Hawking to formulate his chronology protection conjecture, whereby the formation of ''time machines'' is forbidden. This paper will use several simple examples to argue that the Universe appears to exhibit a ''defense in depth'' strategy in this regard. For appropriate parameter regimes, Casimir effects, wormhole disruption effects, and gravitational back reaction effects all contribute to the fight against time travel. Particular attention is paid to the role of the quantum gravity cutoff. For the class of model problems considered it is shown that the gravitational back reaction becomes large before the Planck scale quantum gravity cutoff is reached, thus supporting Hawking's conjecture

  3. Chronological age estimation based on third molar development in a Portuguese population.

    Science.gov (United States)

    Caldas, Inês Morais; Júlio, Paula; Simões, Ricardo Jorge; Matos, Eduarda; Afonso, Américo; Magalhães, Teresa

    2011-03-01

    Third molar development was assessed using a sample of 1,131 orthopantomograms from a Portuguese population. The methodology applied was the eight stages (A-H) method described by Demirjian et al. The final sample was made of 739 orthopantomograms, 387 (52.5%) of which belonging to females; age ranged between 6.1 and 22.5 years old (mean age = 14.49, S.D. = 4.37). For each developmental stage, mean age, standard deviation, and minimal and maximal age was assessed; evaluation of the rate formation of each tooth, according to sex, was calculated and data distribution expressed in percentiles for each stage; the probability of an individual being 16 was also evaluated. The relationship between tooth development and chronological age had a statistical significance for all teeth and both sexes (p thesis that each population need specific data.

  4. From wormhole to time machine Comments on Hawking's Chronology Protection Conjecture

    CERN Document Server

    Visser, B M

    1993-01-01

    The recent interest in ``time machines'' has been largely fueled by the apparent ease with which such systems may be formed in general relativity, given relatively benign initial conditions such as the existence of traversable wormholes or of infinite cosmic strings. This rather disturbing state of affairs has led Hawking to formulate his Chronology Protection Conjecture, whereby the formation of ``time machines'' is forbidden. This paper will use several simple examples to argue that the universe appears to exhibit a ``defense in depth'' strategy in this regard. For appropriate parameter regimes Casimir effects, wormhole disruption effects, and gravitational back reaction effects all contribute to the fight against time travel. Particular attention is paid to the role of the quantum gravity cutoff. For the class of model problems considered it is shown that the gravitational back reaction becomes large before the Planck scale quantum gravity cutoff is reached, thus supporting Hawking's conjecture.

  5. A chronology of Late-Pleistocene permafrost events in southern New Jersey, eastern USA

    Science.gov (United States)

    French, H.M.; Demitroff, M.; Forman, S.L.; Newell, W.L.

    2007-01-01

    Frost fissures, filled with wind-abraded sand and mineral soil, and numerous small-scale non-diastrophic deformations, occur in the near-surface sediments of the Pine Barrens of southern New Jersey. The fissures are the result of thermal-contraction cracking and indicate the previous existence of either permafrost or seasonally-frozen ground. The deformations reflect thermokarst activity that occurred when permafrost degraded, icy layers melted and density-controlled mass displacements occurred in water-saturated sediments. Slopes and surficial materials of the area reflect these cold-climate conditions. Optically-stimulated luminescence permits construction of a tentative Late-Pleistocene permafrost chronology. This indicates Illinoian, Early-Wisconsinan and Late-Wisconsinan episodes of permafrost and/or deep seasonal frost and a Middle-Wisconsinan thermokarst event. Copyright ?? 2007 John Wiley & Sons, Ltd.

  6. Clinician Responses to Client Traumas: A Chronological Review of Constructs and Terminology.

    Science.gov (United States)

    Newell, Jason M; Nelson-Gardell, Debra; MacNeil, Gordon

    2016-07-01

    This paper presents a chronologically-organized review of various concepts and constructs in the literature describing professional burnout, compassion fatigue, secondary traumatic stress reactions, as well as other related terms and constructs that have been used to describe these experiences among clinical practitioners and other social service professionals. A timeline will provide a graphic illustration of the historical relationships between the concepts under examination. This paper begins with a review of practitioner-related stress that primarily results from interaction with clients, followed by an examination of professional burnout, which is thought to result largely from environmentally-related issues. Finally, the paper concludes with a discussion of posttraumatic growth and compassion satisfaction. PMID:25951839

  7. Precipitation reconstruction using ring-width chronology of Himalayan cedar from western Himalaya: Preliminary results

    Indian Academy of Sciences (India)

    Ram R Yadav; Won-Kyu Park

    2000-09-01

    Himalayan cedar (Cedrus deodara (D. Don) G. Don) due to its long age and wide ecological amplitude in the Himalayan region has strong dendroclimatic potential. A well replicated ring-width chronology of it, derived from the ensemble of tree-ring samples of two adjacent homogeneous sites, has been used to reconstruct precipitation for the non-monsoon months (previous year October to concurrent May) back to AD 1171. This provides the first record of hydrological conditions for the western Himalayan region, India during the whole of the `Little Ice Age' and latter part of the `Medieval Warm Period'. The reconstruction revealed the wettest and the driest non-monsoon months during the fourteenth and the thirteenth centuries, respectively. The seventeenth century consistently recorded dry non-monsoon months in the western Himalayan region. Surplus precipitation, especially more pronounced since the 1950s, is recorded in the current century.

  8. Chronology of Fabry-Perot interferometer fiber-optic sensors and their applications: a review.

    Science.gov (United States)

    Islam, Md Rajibul; Ali, Muhammad Mahmood; Lai, Man-Hong; Lim, Kok-Sing; Ahmad, Harith

    2014-04-24

    Optical fibers have been involved in the area of sensing applications for more than four decades. Moreover, interferometric optical fiber sensors have attracted broad interest for their prospective applications in sensing temperature, refractive index, strain measurement, pressure, acoustic wave, vibration, magnetic field, and voltage. During this time, numerous types of interferometers have been developed such as Fabry-Perot, Michelson, Mach-Zehnder, Sagnac Fiber, and Common-path interferometers. Fabry-Perot interferometer (FPI) fiber-optic sensors have been extensively investigated for their exceedingly effective, simple fabrication as well as low cost aspects. In this study, a wide variety of FPI sensors are reviewed in terms of fabrication methods, principle of operation and their sensing applications. The chronology of the development of FPI sensors and their implementation in various applications are discussed.

  9. Gamma Spectrometry for Chronology of Recent Sediments. Tracing Human Induced Climate Change in NW Africa

    International Nuclear Information System (INIS)

    Gamma spectroscopy was used for the determination of radionuclides in sediment cores from the continental shelf off northwest africa to provide age control of the sediment record used for a study of aridification of the Sahel zone. 210Pb, 226Ra and 137Cs were measured in the upper part of a gravity core and the associated multicorer and used for aligning these cores. This provided information about the amount of sediment loss due to the sampling procedure in the upper part of the gravity core. The age model based on the matched profiles extended to 140 years B.P. and the rest of the gravity core was dated by 14C. The 210Pb age allowed the estimation of the local radiocarbon reservoir age. Application of 210Pb and 137Cs chronology helps to significantly extend paleoclimatic proxy data into the Anthropocene, thereby allowing the comparison of human induced climate change with natural climate variability. (author)

  10. Chronological age affects the permeation of fentanyl through human skin in vitro

    DEFF Research Database (Denmark)

    Holmgaard, R; Benfeldt, E; Sorensen, J A;

    2013-01-01

    AIM: To study the influence of chronological age on fentanyl permeation through human skin in vitro using static diffusion cells. Elderly individuals are known to be more sensitive to opioids and obtain higher plasma concentrations following dermal application of fentanyl compared to younger...... individuals. The influence of age - as an isolated pharmacokinetic term - on the absorption of fentanyl has not been previously studied. METHOD: Human skin from 30 female donors was mounted in static diffusion cells, and samples were collected during 48 h. Donors were divided into three age groups: ... and old age groups: 5,922 and 4,050 ng, respectively). Furthermore, the lag time and absorption rate were different between the three groups, with a significantly higher rate in the young participants versus the oldest participants. CONCLUSION: We demonstrate that fentanyl permeates the skin of young...

  11. Isotopic chronology and geological events of Precambrian complex in Taihangshan region

    Institute of Scientific and Technical Information of China (English)

    刘树文; 梁海华; 赵国春; 华永刚; 简安华

    2000-01-01

    There are five major geological events in Precambrian complex, Taihangshan region determined by researching into geology and isotopic chronology of the complex. Basaltic magma erupted and quartz-dioritic to tonalitic magma intruded in earlier neo-Archaean, which formed horn-blende-plagiogneiss of Fuping gneiss complex and metamorphic mafic rock enclaves in TTG gneiss complex. Granulite fades metamorphism and emplacement of biotite-plagiogneiss occurred in late neo-Archaean. Extension and uplifting from the end of neo-Archaean to Paleoproterozoic era formed Chengnanzhuang large extensional deformation zones and metamorphic mafic veins emplaced into the deformation zones. Remobilization of Precambrian complex and tectonic uplifting in late Paleoproterozoic era formed Longquanguan ductile shear zone and emplacement of Nanying gneiss. Occurrence of regional granite pegmatite at the end of Paleoproterozoic era means the end of the Luliang movement.

  12. Isotopic chronology and geological events of Precambrian complex in Taihangshan region

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    There are five major geological events in Precambrian complex, Taihangshan region determined by researching into geology and isotopic chronology of the complex. Basaltic magma erupted and quartz-dioritic to tonalitic magma intruded in earlier neo-Archaean, which formed hornblende-plagiogneiss of Fuping gneiss complex and metamorphic mafic rock enclaves in TTG gneiss complex. Granulite facies metamorphism and emplacement of biotite-plagiogneiss occurred in late neo-Archaean. Extension and uplifting from the end of neo-Archaean to Paleoproterozoic era formed Chengnanzhuang large extensional deformation zones and metamorphic mafic veins emplaced into the deformation zones. Remobilization of Precambrian complex and tectonic uplifting in late Paleoproterozoic era formed Longquanguan ductile shear zone and emplacement of Nanying gneiss. Occurrence of regional granite pegmatite at the end of Paleoproterozoic era means the end of the Lliang movement.

  13. Anchoring historical sequences using a new source of astro-chronological tie-points

    Science.gov (United States)

    Dee, Michael W.; Pope, Benjamin J. S.

    2016-08-01

    The discovery of past spikes in atmospheric radiocarbon activity, caused by major solar energetic particle events, has opened up new possibilities for high-precision chronometry. The two spikes, or Miyake Events, have now been widely identified in tree-rings that grew in the years 775 and 994 CE. Furthermore, all other plant material that grew in these years would also have incorporated the anomalously high concentrations of radiocarbon. Crucially, some plant-based artefacts, such as papyrus documents, timber beams and linen garments, can also be allocated to specific positions within long, currently unfixed, historical sequences. Thus, Miyake Events represent a new source of tie-points that could provide the means for anchoring early chronologies to the absolute timescale. Here, we explore this possibility, outlining the most expeditious approaches, the current challenges and obstacles, and how they might best be overcome.

  14. A Companion to Astronomy and Astrophysics Chronology and Glossary with Data Tables

    CERN Document Server

    Lang, Kenneth R

    2006-01-01

    Astronomy and Astrophysics is a comprehensive, fundamental, up-to-date reference book. It is filled with vital information and basic facts for amateur astronomers and professional astrophysicists, and for anyone interested in the Universe, from the Earth and other planets to the stars, galaxies and beyond. Although serious and thorough, the language, and ideas will attract the general reader, as well as students and professionals. Astronomy and Astrophysics consists of two main parts, a Timeline and a Dictionary. The Timeline is a concise history, arranged chronologically, which provides the complete story of cosmic discovery from early Chinese and Greek astronomy to the latest findings of modern astrophysics and robotic spacecraft. It provides a sense of destination and flow in our growing awareness of the Universe. Each entry in the unfolding narrative is written in a concise, light and friendly style that will be appreciated by all, without being weighted down with incomprehensible specialized terms. The s...

  15. Effects of irradiation on minerals and their consequences in geo-chronology

    International Nuclear Information System (INIS)

    In this HDR (accreditation to supervise research studies) report, the author first gives a brief overview of her scientific approach. Then, addressing the irradiation of minerals by a radioactive source, she discusses the effects of irradiation, notably in the case of monazite, reports an experimental approach of external irradiation by ion beams, and comments some side effects like irradiation of host minerals. She also comments how irradiation-induced damages interfere with some processes like diffusion kinetics and dissolution. She addresses the case of mineral irradiation by means of a femto-second laser source: scientific approach, effects on mineral microstructure, notably in the case of monazite and quartz. The last part discusses issues in abeyance and perspectives in the field of irradiation textures, consequences on the geo-chronological response, alteration mechanisms, role of defects, and contribution of experimental irradiation

  16. Radiobiological investigations at tumor cell lines by exploiting chrono-biological aspects of chronological dose distributions

    CERN Document Server

    Ulmer, W

    2011-01-01

    Using 31P-NMR spectroscopy the chronological behavior of the ATP-metabolism of the tumor spheroids C3H-MA, 9L-Gliome and the mono-layer L1210 has been analyzed via decrease of the {\\beta}-peak. All three cell lines show characteristic periods, and a homeostatic control cannot be recognized. Essential components of these periods are circadian (i.e. one day), circa-semiseptan (i.e. 3.5 days) and circa-septan (i.e. one week). The determination of the survival fractions provides an optimum exploitation of radiation damages, when the ATP-concentration assumes a maximum value. This optimum is reached, when all three cycles exhibit the ATP maximum, which is only possible by accounting for the circa-septan rhythm. The goal of this study is to elaborate an optimal fractionation scheme with regard to the irradiation of tumors.

  17. Modeling of the evolution of steppe chernozems and development of the method of pedogenetic chronology

    Science.gov (United States)

    Lisetskii, F. N.; Stolba, V. F.; Goleusov, P. V.

    2016-08-01

    Geoarchaeological methods were used to study chronosequences of surface soils in the steppe zone and to trace soil evolution during the Late Holocene in northwestern Crimea. It was found that the morphological and functional "maturity" of the humus horizons in steppe chernozems of the Late Holocene was reached in about 1600-1800 yrs. After this, their development decelerated irreversibly. The maximum concentration of trace elements accumulated in these horizons in the course of pedogenesis was reached in 1400 yrs. A new method of pedogenetic chronology based on the model chronofunction of the development of irreversible results of pedogenesis over time is suggested. Original pedochronological data and growth functions—the most suitable models for simulating pedogenesis over the past three thousand years—suggest that the development of morphological features of soil as an organomineral natural body follows growth patterns established for biological systems.

  18. Chronological Trends in Negev Rock Art: The Har Michia Petroglyphs as a Test Case

    Directory of Open Access Journals (Sweden)

    Davida Eisenberg-Degen

    2013-10-01

    Full Text Available Negev rock art comprises a large and diverse corpus of motifs and compositions developed over the course of several millennia. As dating of specific elements is at present not possible, the rock art was analyzed statistically through the study of individual panels where internal sequences of engraving could be discerned. Examining the set of such individual sequences, larger scale reconstruction of engraving phases, sequences and patterns were recognized. Additional chronological markers, such as the presence of domestic camels or other chronologically diagnostic features, offer benchmarks for tying the general trends to more absolute frameworks. The reconstructed patterns reflect the long term history of the Negev and some of the most significant cultural and social transitions in the region are reflected visually through the rock art, notably a form of self-expression, a crucial complement to the historical sequences derived from sedentary peoples living farther north. For example the introduction of the domestic camel and its symbolic and economic significance is well evident in the rock art. Similarly, the emergence of Islam is expressed through the mark makers’ preference for "abstract" (non-figurative motifs. One motif found throughout all engraving phases, transcending the religious, political and economic structures of Negev society, is the “ibex”. Although Negev societies have all focused, to one degree or another, on sheep and goat pastoralism, these animals are rarely present in the Negev rock art and never as herds. Ibex, whose role in the diet and daily subsistence was minimal, was the most commonly depicted zoomorphic motif.

  19. Chronology and impact of the 2011 Cordón Caulle eruption, Chile

    Science.gov (United States)

    Elissondo, Manuela; Baumann, Valérie; Bonadonna, Costanza; Pistolesi, Marco; Cioni, Raffaello; Bertagnini, Antonella; Biass, Sébastien; Herrero, Juan-Carlos; Gonzalez, Rafael

    2016-03-01

    We present a detailed chronological reconstruction of the 2011 eruption of the Cordón Caulle volcano (Chile) based on information derived from newspapers, scientific reports and satellite images. Chronology of associated volcanic processes and their local and regional effects (i.e. precursory activity, tephra fallout, lahars, pyroclastic density currents, lava flows) are also presented. The eruption had a severe impact on the ecosystem and on various economic sectors, including aviation, tourism, agriculture and fishing industry. Urban areas and critical infrastructures, such as airports, hospitals and roads, were also impacted. The concentration of PM10 (particulate matter ≤ 10 µm) was measured during and after the eruption, showing that maximum safety threshold levels of daily and annual exposures were surpassed in several occasions. Probabilistic analyses suggest that this combination of atmospheric and eruptive conditions has a probability of occurrence of about 1 %. The management of the crisis, including evacuation of people, is discussed, as well as the comparison with the impact associated with other recent eruptions located in similar areas and having similar characteristics (i.e. Quizapu, Hudson and Chaitén volcanoes). This comparison shows that the regions downwind and very close to the erupting volcanoes suffered very similar problems, without a clear relation to the intensity of the eruption (e.g. health problems, damage to vegetation, death of animals, roof collapse, air traffic disruptions, road closure, lahars and flooding). This suggests that a detailed collection of impact data can be largely beneficial for the development of plans for the management of an eruptive crisis and the mitigation of associated risk of the Andean region.

  20. Radiobiological investigations at tumor cell lines by exploiting aspects of chronological dose administration

    Directory of Open Access Journals (Sweden)

    Waldemar Ulmer

    2014-08-01

    Full Text Available Purpose: Using 31P-NMR spectroscopy the chronological behavior of the ATP-metabolism of the tumor spheroids C3H-MA, 9L-Gliome and the mono-layer L1210 has been analyzed via increase and decrease of the β-peak. The goal of this study is to elaborate an optimal fractionation scheme with regard to the irradiation of tumor spheroids and possibly to human tumors.  Methods: The NMR-spectroscopy has been carried out by the FID technique (free induction decay, and the intensity of the β-peak provides a measure of the survival fraction S after radiation exposure with 30 kV X-rays. The linear-quadratic model has to be generalized in order to be valid for irradiation beyond the shoulder. Results and Conclusion: All three cell lines show characteristic periods, and a homeostatic control cannot be recognized. Essential components of these periods are circadian (i.e. one day, circa-semiseptan (i.e. 3.5 days and circa-septan (i.e. one week. The determination of the survival fractions provides an optimum exploitation of radiation damages, when the ATP-concentration assumes a maximum value. This optimum is reached, when all three cycles exhibit an ATP maximum, which is only possible by accounting for the circa-septan rhythm.--------------------------------------Cite this article as: Ulmer W. Radiobiological investigations at tumor cell lines by exploiting aspects of chronological dose administration. Int J Cancer Ther Oncol 2014; 2(3:020312. DOI:10.14319/ijcto.0203.12 

  1. Correlation between chronological variables of the epileptic seizures and ictal perfusion patterns in temporal lobe epilepsy

    International Nuclear Information System (INIS)

    Ictal SPECT has a high sensitivity to localise the epileptogenic zone (EZ) in medically intractable temporal lobe epilepsies (TLE). Much is already known about timing of postictal perfusional patterns, while little data analysing ictal perfusion patterns under a chronological frame exists. This study addresses the issue of typical and atypical perfusion patterns in temporal lobes and correlates them with ictal chronological variables. We prospectively evaluated 53 patients (pts) with unilateral TLE through Video-EEG, MRI, ictal, postictal and interictal SPECT, neuropsychological, social and psychiatric evaluations. All patients underwent antero-mesial temporal lobectomy and had a good post surgical seizure outcome. We analysed 51 ictal and 2 postictal scans: 41 pts (77%) showed typical perfusional patterns (TPP, ie, ictal hyperperfusion or postictal hypoperfusion ipsilateral to the EZ); 12 pts (23%) exhibited atypical perfusion patterns (ATT): 7 pts (13%) with bitemporal hyperperfusion (4 pts showed asymmetric predominantly ipsilateral changes), other 4 pts (8%) had contralateral hyperperfusion (associated to ipsilateral hypoperfusion) and 1 patient (2%) had a normal ictal SPECT scan. The earlier injection group (up to 30 sec from seizure onset) had a greater percentage of TPP (p<0,05). There was a significantly greater ictal electroencephalographic pattern exceeding radionuclide injection in TPP than APP group (p<0,04). Later acquisition of SPECT images (between 2 and 6 hours after injection) did not influence the sensitivity of the SPECT. Ictal perfusion patterns in TLE needs detailed morphological analysis to determine TPP and APP. After electro-clinical correlation, APP discloses conspicuous findings that can also render them lateralising information of EZ. Early injection of radionuclide resulted in a greater percentage of TPP. Later SPECT acquisitions had similar sensitivity to the earlier ones. Finally, greater exceeding time of ictal EEG after radionuclide

  2. Chronology and impact of the 2011 Puyehue-Cordón Caulle eruption, Chile

    Science.gov (United States)

    Elissondo, M.; Baumann, V.; Bonadonna, C.; Pistolesi, M.; Cioni, R.; Bertagnini, A.; Biass, S.; Herrero, J. C.; Gonzalez, R.

    2015-09-01

    We present a detailed chronological reconstruction of the 2011 eruption of Puyehue-Cordón Caulle volcano (Chile) based on information derived from newspapers, scientific reports and satellite images. Chronology of associated volcanic processes and their local and regional effects (i.e. precursory activity, tephra fallout, lahars, pyroclastic density currents, lava flows) are also presented. The eruption had a severe impact on the ecosystem and on various economic sectors, including aviation, tourism, agriculture, and fishing industry. Urban areas and critical infrastructures, such as airports, hospitals and roads, were also impacted. The concentration of PM10 (Particulate Matter ≤ 10 μm) was measured during and after the eruption, showing that maximum safety threshold levels of daily and annual exposures were surpassed in several occasions. Probabilistic analysis of atmospheric and eruptive conditions have shown that the main direction of dispersal is directly towards east of the volcano and that the climactic phase of the eruption, dispersed toward south-east, has a probability of occurrence within 1 %. The management of the crisis, including evacuation of people, is discussed, as well as the comparison with the impact associated with other recent eruptions located in similar areas and having similar characteristics (i.e. Quizapu, Hudson, and Chaitén volcanoes). This comparison shows that the regions downwind and very close to the erupting volcanoes suffered very similar problems, without a clear relation with the intensity of the eruption (e.g. health problems, damage to vegetation, death of animals, roof collapse, air traffic disruptions, road closure, lahars and flooding). This suggests that a detailed collection of impact data can be largely beneficial for the development of plans for the management of an eruptive crisis and the mitigation of associated risk of the Andean region.

  3. The Later Stone Age calvaria from Iwo Eleru, Nigeria: morphology and chronology.

    Directory of Open Access Journals (Sweden)

    Katerina Harvati

    Full Text Available BACKGROUND: In recent years the Later Stone Age has been redated to a much deeper time depth than previously thought. At the same time, human remains from this time period are scarce in Africa, and even rarer in West Africa. The Iwo Eleru burial is one of the few human skeletal remains associated with Later Stone Age artifacts in that region with a proposed Pleistocene date. We undertook a morphometric reanalysis of this cranium in order to better assess its affinities. We also conducted Uranium-series dating to re-evaluate its chronology. METHODOLOGY/PRINCIPAL FINDINGS: A 3-D geometric morphometric analysis of cranial landmarks and semilandmarks was conducted using a large comparative fossil and modern human sample. The measurements were collected in the form of three dimensional coordinates and processed using Generalized Procrustes Analysis. Principal components, canonical variates, Mahalanobis D(2 and Procrustes distance analyses were performed. The results were further visualized by comparing specimen and mean configurations. Results point to a morphological similarity with late archaic African specimens dating to the Late Pleistocene. A long bone cortical fragment was made available for U-series analysis in order to re-date the specimen. The results (∼11.7-16.3 ka support a terminal Pleistocene chronology for the Iwo Eleru burial as was also suggested by the original radiocarbon dating results and by stratigraphic evidence. CONCLUSIONS/SIGNIFICANCE: Our findings are in accordance with suggestions of deep population substructure in Africa and a complex evolutionary process for the origin of modern humans. They further highlight the dearth of hominin finds from West Africa, and underscore our real lack of knowledge of human evolution in that region.

  4. Chronology and ancient feeding ecology of two upper Pleistocene megamammals from the Brazilian Intertropical Region

    Science.gov (United States)

    de Melo França, Lucas; Trindade Dantas, Mário André; Bocchiglieri, Adriana; Cherckinsky, Alexander; de Souza Ribeiro, Adauto; Bocherens, Hervé

    2014-09-01

    In Brazilian Intertropical Region (BIR) fossil remains of the giant ground sloth Eremotherium laurillardi (Lund, 1842) and of the proboscidean Notiomastodon platensis (Ameghino, 1888) are the most abundant among megaherbivores. However, the paleoecology of both species needs to be better understood to enlighten why these species disappear in the end of the Pleistocene, an issue that is still debated. During the last decades, the carbon and oxygen stable isotopes have been increasingly being used to obtain paleoecological information about extinct animals, although this information is in most cases dissociated from chronological data. Thus, the main objective of this study is to contribute to the knowledge about feeding ecology and chronology of E. laurillardi and N. platensis within BIR. For each fossil sample we performed stable isotopes analyses (δ13C/δ18O) and radiocarbon dating (14C with AMS). The results showed that N. platensis occurred between 12,125 and 19,594 cal yr BP and exhibited a grazer diet (δ13C = -1.1‰-1.3‰), while E. laurillardi lived between 11,084 and 27,690 cal yr BP, with a mixed feeder diet (C3/C4 plants; values ratio δ13C = -7.7‰ to -3.3‰). The δ18O values of N. platensis ranged between 2.20‰ and 3.60‰, while the values of E. laurillardi ranged between -3.10‰ and -1.10‰. Neither species did exhibit differences in its diet through time, which suggests that the vegetational composition of this locality did not vary in the late Pleistocene. Both species were living in an open environment, rich in herbaceous plants (C4 plants) and with tree and shrub with disjoint distribution, maybe similar to some parts of recent Caatinga, where they have partitioned the spatial and feeding niches.

  5. Chronology and impact of the 2011 Puyehue-Cordón Caulle eruption, Chile

    Directory of Open Access Journals (Sweden)

    M. Elissondo

    2015-09-01

    Full Text Available We present a detailed chronological reconstruction of the 2011 eruption of Puyehue-Cordón Caulle volcano (Chile based on information derived from newspapers, scientific reports and satellite images. Chronology of associated volcanic processes and their local and regional effects (i.e. precursory activity, tephra fallout, lahars, pyroclastic density currents, lava flows are also presented. The eruption had a severe impact on the ecosystem and on various economic sectors, including aviation, tourism, agriculture, and fishing industry. Urban areas and critical infrastructures, such as airports, hospitals and roads, were also impacted. The concentration of PM10 (Particulate Matter ≤ 10 μm was measured during and after the eruption, showing that maximum safety threshold levels of daily and annual exposures were surpassed in several occasions. Probabilistic analysis of atmospheric and eruptive conditions have shown that the main direction of dispersal is directly towards east of the volcano and that the climactic phase of the eruption, dispersed toward south-east, has a probability of occurrence within 1 %. The management of the crisis, including evacuation of people, is discussed, as well as the comparison with the impact associated with other recent eruptions located in similar areas and having similar characteristics (i.e. Quizapu, Hudson, and Chaitén volcanoes. This comparison shows that the regions downwind and very close to the erupting volcanoes suffered very similar problems, without a clear relation with the intensity of the eruption (e.g. health problems, damage to vegetation, death of animals, roof collapse, air traffic disruptions, road closure, lahars and flooding. This suggests that a detailed collection of impact data can be largely beneficial for the development of plans for the management of an eruptive crisis and the mitigation of associated risk of the Andean region.

  6. Organic carbon sedimentation rates in Asian mangrove coastal ecosystems estimated by {sup 210}PB chronology

    Energy Technology Data Exchange (ETDEWEB)

    Tateda, Y.; Wattayakorn, G.; Nhan, D.D.; Kasuya, Y. [Abiko Research Laboratory CRIEPI, Biology Dept., Abiko, Chiba (Japan)

    2004-07-01

    Organic carbon balance estimation of mangrove coastal ecosystem is important for understanding of Asian coastal carbon budget/flux calculation in global carbon cycle modelling which is powerful tool for the prediction of future greenhouse gas effect and evaluation of countermeasure preference. Especially, the organic carbon accumulation rate in mangrove ecosystem was reported to be important sink of carbon as well as that in boreal peat accumulation. For the estimation of 10{sup 3} years scale organic carbon accumulation rates in mangrove coastal ecosystems, {sup 14}C was used as long term chronological tracer, being useful in pristine mangrove forest reserve area. While in case of mangrove plantation of in coastal area, the {sup 210}Pb is suitable for the estimation of decades scale estimation by its half-life. Though it has possibility of bio-/physical- turbation effect in applying {sup 210}Pb chronology that is offset in case of 10{sup 3} years scale estimation, especially in Asian mangrove ecosystem where the anthropogenic physical turbation by coastal fishery is vigorous.In this paper, we studied the organic carbon and {sup 210}Pb accumulation rates in subtropical mangrove coastal ecosystems in Japan, Vietnam and Thailand with {sup 7}Be analyses to make sure the negligible effect of above turbation effects on organic carbon accumulation. We finally concluded that {sup 210}Pb was applicable to estimate organic carbon accumulation rates in these ecosystems even though the physical-/bio-turbation is expected. The measured organic carbon accumulation rates using {sup 210}Pb in mangrove coastal ecosystems of Japan, Vietnam and Thailand were 0.067 4.0 t-C ha{sup -1} y{sup -1}. (author)

  7. Chronology of Pu isotopes and 236U in an Arctic ice core.

    Science.gov (United States)

    Wendel, C C; Oughton, D H; Lind, O C; Skipperud, L; Fifield, L K; Isaksson, E; Tims, S G; Salbu, B

    2013-09-01

    In the present work, state of the art isotopic fingerprinting techniques are applied to an Arctic ice core in order to quantify deposition of U and Pu, and to identify possible tropospheric transport of debris from former Soviet Union test sites Semipalatinsk (Central Asia) and Novaya Zemlya (Arctic Ocean). An ice core chronology of (236)U, (239)Pu, and (240)Pu concentrations, and atom ratios, measured by accelerator mass spectrometry in a 28.6m deep ice core from the Austfonna glacier at Nordaustlandet, Svalbard is presented. The ice core chronology corresponds to the period 1949 to 1999. The main sources of Pu and (236)U contamination in the Arctic were the atmospheric nuclear detonations in the period 1945 to 1980, as global fallout, and tropospheric fallout from the former Soviet Union test sites Novaya Zemlya and Semipalatinsk. Activity concentrations of (239+240)Pu ranged from 0.008 to 0.254 mBq cm(-2) and (236)U from 0.0039 to 0.053 μBq cm(-2). Concentrations varied in concordance with (137)Cs concentrations in the same ice core. In contrast to previous published results, the concentrations of Pu and (236)U were found to be higher at depths corresponding to the pre-moratorium period (1949 to 1959) than to the post-moratorium period (1961 and 1962). The (240)Pu/(239)Pu ratio ranged from 0.15 to 0.19, and (236)U/(239)Pu ranged from 0.18 to 1.4. The Pu atom ratios ranged within the limits of global fallout in the most intensive period of nuclear atmospheric testing (1952 to 1962). To the best knowledge of the authors the present work is the first publication on biogeochemical cycles with respect to (236)U concentrations and (236)U/(239)Pu atom ratios in the Arctic and in ice cores.

  8. Altered Lipid Synthesis by Lack of Yeast Pah1 Phosphatidate Phosphatase Reduces Chronological Life Span.

    Science.gov (United States)

    Park, Yeonhee; Han, Gil-Soo; Mileykovskaya, Eugenia; Garrett, Teresa A; Carman, George M

    2015-10-16

    In Saccharomyces cerevisiae, Pah1 phosphatidate phosphatase, which catalyzes the dephosphorylation of phosphatidate to yield diacylglycerol, plays a crucial role in the synthesis of the storage lipid triacylglycerol. This evolutionarily conserved enzyme also plays a negative regulatory role in controlling de novo membrane phospholipid synthesis through its consumption of phosphatidate. We found that the pah1Δ mutant was defective in the utilization of non-fermentable carbon sources but not in oxidative phosphorylation; the mutant did not exhibit major changes in oxygen consumption rate, mitochondrial membrane potential, F1F0-ATP synthase activity, or gross mitochondrial morphology. The pah1Δ mutant contained an almost normal complement of major mitochondrial phospholipids with some alterations in molecular species. Although oxidative phosphorylation was not compromised in the pah1Δ mutant, the cellular levels of ATP in quiescent cells were reduced by 2-fold, inversely correlating with a 4-fold increase in membrane phospholipids. In addition, the quiescent pah1Δ mutant cells had 3-fold higher levels of mitochondrial superoxide and cellular lipid hydroperoxides, had reduced activities of superoxide dismutase 2 and catalase, and were hypersensitive to hydrogen peroxide. Consequently, the pah1Δ mutant had a shortened chronological life span. In addition, the loss of Tsa1 thioredoxin peroxidase caused a synthetic growth defect with the pah1Δ mutation. The shortened chronological life span of the pah1Δ mutant along with its growth defect on non-fermentable carbon sources and hypersensitivity to hydrogen peroxide was suppressed by the loss of Dgk1 diacylglycerol kinase, indicating that the underpinning of pah1Δ mutant defects was the excess synthesis of membrane phospholipids. PMID:26338708

  9. The WAIS Divide deep ice core WD2014 chronology – Part 2: Annual-layer counting (0–31 ka BP

    Directory of Open Access Journals (Sweden)

    M. Sigl

    2015-07-01

    Full Text Available We present the WD2014 chronology for the upper part (0–2850 m, 31.2 ka BP of the West Antarctic Ice Sheet (WAIS Divide ice core. The chronology is based on counting of annual layers observed in the chemical, dust and electrical conductivity records. These layers are caused by seasonal changes in the source, transport, and deposition of aerosols. The measurements were interpreted manually and with the aid of two automated methods. We validated the chronology by comparing to two high-accuracy, absolutely dated chronologies. For the Holocene, the cosmogenic isotope records of 10Be from WAIS Divide and 14C for Intcal13 demonstrated WD2014 was consistently accurate to better than 0.5 % of the age. For the glacial period, comparisons to the Hulu Cave chronology demonstrated WD2014 had an accuracy of better than 1 % of the age at three abrupt climate change events between 27 and 31 ka. WD2014 has consistently younger ages than Greenland ice-core chronologies during most of the Holocene. For the Younger Dryas-Preboreal transition (11 546 ka BP, 24 years younger and the Bølling-Allerød Warming (14 576 ka, 7 years younger WD2014 ages are within the combined uncertainties of the timescales. Given its high accuracy, WD2014 can become a reference chronology for the Southern Hemisphere, with synchronization to other chronologies feasible using high quality proxies of volcanism, solar activity, atmospheric mineral dust, and atmospheric methane concentrations.

  10. THE MINOAN SANTORINI ERUPTION AND TSUNAMI DEPOSITS IN PALAIKASTRO (CRETE) : DATING BY GEOLOGY, ARCHAEOLOGY, C-14, AND EGYPTIAN CHRONOLOGY

    NARCIS (Netherlands)

    Bruins, Hendrik J.; van der Plicht, Johannes; MacGillivray, Alexander

    2009-01-01

    Deposits from the Minoan Santorini (Thera) eruption in the eastern Mediterranean region Constitute the most important regional stratigraphic marker in the chronological perplexity of the 2nd Millennium BCE. Extensive tsunami deposits were discovered in Crete at the Minoan archaeological site of Pala

  11. Quality assessment of chronologies in Latin American pollen records: a contribution to centennial to millennial scale studies of environmental change

    NARCIS (Netherlands)

    S.G.A. Flantua; H. Hooghiemstra; M. Blaauw

    2015-01-01

    The newly updated inventory of the Latin American Pollen Database (LAPD) offers an important overview of data available for multi-proxy and multi-site purposes. However, heterogeneous paleoecological databases are not suitable to be integrated without an uncertainty assessment of existing chronologi

  12. Modelling Developmental Changes in Repeated-Sprint Ability by Chronological and Skeletal Ages in Young Soccer Players

    NARCIS (Netherlands)

    Valente-dos-Santos, J.; Coelho-e-Silva, M. J.; Martins, R. A.; Figueiredo, A. J.; Cyrino, E. S.; Sherar, L. B.; Vaeyens, R.; Huijgen, B. C. H.; Elferink-Gemser, M. T.; Malina, R. M.

    2012-01-01

    This study investigated the influence of chronological (CA) and skeletal ages (SA), anthropometry, aerobic endurance and lower limb explosive strength on developmental changes in repeated-sprint ability (RSA) in soccer players aged 11-17 years. Participants were annually followed over 5 years, resul

  13. Absolute ages from crater statistics: Using radiometric ages of Martian samples for determining the Martian cratering chronology

    Science.gov (United States)

    Neukum, G.

    1988-01-01

    In the absence of dates derived from rock samples, impact crater frequencies are commonly used to date Martian surface units. All models for absolute dating rely on the lunar cratering chronology and on the validity of its extrapolation to Martian conditions. Starting from somewhat different lunar chronologies, rather different Martian cratering chronologies are found in the literature. Currently favored models are compared. The differences at old ages are significant, the differences at younger ages are considerable and give absolute ages for the same crater frequencies as different as a factor of 3. The total uncertainty could be much higher, though, since the ratio of lunar to Martian cratering rate which is of basic importance in the models is believed to be known no better than within a factor of 2. Thus, it is of crucial importance for understanding the the evolution of Mars and determining the sequence of events to establish an unambiguous Martian cratering chronology from crater statistics in combination with clean radiometric ages of returned Martian samples. For the dating goal, rocks should be as pristine as possible from a geologically simple area with a one-stage emplacement history of the local formation. A minimum of at least one highland site for old ages, two intermediate-aged sites, and one very young site is needed.

  14. Glycation associated skin autofluorescence and skin elasticity are related to chronological age and body mass index of healthy subjects

    OpenAIRE

    Corstjens, H.; Dicanio, D.; Muizzuddin, N.; Neven, A.; Sparacio, R.; Declercq, L; D. Maes

    2008-01-01

    Glycation associated skin autofluorescence and skin elasticity are related to chronological age and body mass index of healthy subjects correspondence: Corresponding author. Tel.: +32 14 25 89 04; fax: +32 14 25 88 60. (Corstjens, H.) (Corstjens, H.) Estee Lauder Companies--> , Oevel--> - BELGIUM (Corstjens, H.) BELGIUM (Corstjens, H.) Estee Lauder Companies--> , Melville--> ,...

  15. Perceived Changes in Well-Being: The Role of Chronological Age, Target Age, and Type of Measure

    Science.gov (United States)

    Okun, Morris A.; Dittburner, Julie L.; Huff, Barbara P.

    2006-01-01

    The goal of this study is to investigate whether perceived changes in one's well-being from the present to the future are related to chronological age, target age, and type of measure (psychological well-being versus life satisfaction). Young adults (N = 114) rated their current well-being and their future well-being at one of three target ages…

  16. Correlation between Dental Maturation and Chronological Age in Patients with Cerebral Palsy, Mental Retardation, and Down Syndrome

    Science.gov (United States)

    Diz, P.; Limeres, J.; Salgado, A. F. P.; Tomas, I.; Delgado, L. F.; Vazquez, E.; Feijoo, J. F.

    2011-01-01

    Determining a child's chronological age and stage of maturation is particularly important in fields such as paediatrics, orthopaedics, and orthodontics, as well as in forensic and anthropological studies. Some systemic conditions can cause abnormal physiological maturation, and skeletal maturation is usually more delayed than dental maturation.…

  17. Ice cores from Arctic sub-polar glaciers : Chronology and post-depositional processes deduced from radioactivity measurements

    NARCIS (Netherlands)

    Pinglot, J.F.; Vaikmae, R.A.; Kamiyama, K.; Igarashi, M.; Fritsche, D.; Wilhalms, F.; Koerner, R.; Henderson, L.; Isaksson, E.; Winther, J.G.; van de Wal, R.S.W.; Fournier, M; Bouisset, P.; Meijer, H.A.J.

    2003-01-01

    The response of Arctic ice masses to climate change is studied using ice cores containing information on past climatic and environmental features. Interpretation of this information requires accurate chronological data. Absolute dating of ice cores from sub-polar Arctic glaciers is possible using we

  18. A new chronology for the Dacian Basin (Romania) : Consequences for the kinematic and paleoenvironmental evolution of the Paratethys region

    NARCIS (Netherlands)

    Vasiliev, I.

    2006-01-01

    This PhD thesis presents new chronostratigraphic results from the Dacian Basin and adjacent regions as part of the Paratethys paleoprovince. In the first three chapters, a new chronology for the Upper Miocene to Pliocene deposits (approximately 8 to 3 Ma) of the Dacian Basin is presented based on hi

  19. Topical versus Chronological Organization of Lifespan Development: Does It Make a Difference in Student Retention and Understanding?

    Science.gov (United States)

    Spangler, Brooke R.; Kiel, Elizabeth J.

    2015-01-01

    This study aimed to determine whether taking a chronological approach (CA) or topical approach (TA) to teaching developmental psychology resulted in different learning outcomes. Across two semesters, in four classes, 354 students participated (M[subscript age] = 19.76, SD[subscript age] = 2.93 years), 66% identifying as female. One instructor…

  20. Integrated Tree-Ring-Radiocarbon High-Resolution Timeframe to Resolve Earlier Second Millennium BCE Mesopotamian Chronology

    Science.gov (United States)

    Griggs, Carol B.; Lorentzen, Brita; Barjamovic, Gojko; Ramsey, Christopher Bronk; Kromer, Bernd; Wild, Eva Maria

    2016-01-01

    500 years of ancient Near Eastern history from the earlier second millennium BCE, including such pivotal figures as Hammurabi of Babylon, Šamši-Adad I (who conquered Aššur) and Zimrilim of Mari, has long floated in calendar time subject to rival chronological schemes up to 150+ years apart. Texts preserved on clay tablets provide much information, including some astronomical references, but despite 100+ years of scholarly effort, chronological resolution has proved impossible. Documents linked with specific Assyrian officials and rulers have been found and associated with archaeological wood samples at Kültepe and Acemhöyük in Turkey, and offer the potential to resolve this long-running problem. Here we show that previous work using tree-ring dating to place these timbers in absolute time has fundamental problems with key dendrochronological crossdates due to small sample numbers in overlapping years and insufficient critical assessment. To address, we have integrated secure dendrochronological sequences directly with radiocarbon (14C) measurements to achieve tightly resolved absolute (calendar) chronological associations and identify the secure links of this tree-ring chronology with the archaeological-historical evidence. The revised tree-ring-sequenced 14C time-series for Kültepe and Acemhöyük is compatible only with the so-called Middle Chronology and not with the rival High, Low or New Chronologies. This finding provides a robust resolution to a century of uncertainty in Mesopotamian chronology and scholarship, and a secure basis for construction of a coherent timeframe and history across the Near East and East Mediterranean in the earlier second millennium BCE. Our re-dating also affects an unusual tree-ring growth anomaly in wood from Porsuk, Turkey, previously tentatively associated with the Minoan eruption of the Santorini volcano. This tree-ring growth anomaly is now directly dated ~1681–1673 BCE (68.2% highest posterior density range), ~20

  1. Integrated Tree-Ring-Radiocarbon High-Resolution Timeframe to Resolve Earlier Second Millennium BCE Mesopotamian Chronology.

    Directory of Open Access Journals (Sweden)

    Sturt W Manning

    Full Text Available 500 years of ancient Near Eastern history from the earlier second millennium BCE, including such pivotal figures as Hammurabi of Babylon, Šamši-Adad I (who conquered Aššur and Zimrilim of Mari, has long floated in calendar time subject to rival chronological schemes up to 150+ years apart. Texts preserved on clay tablets provide much information, including some astronomical references, but despite 100+ years of scholarly effort, chronological resolution has proved impossible. Documents linked with specific Assyrian officials and rulers have been found and associated with archaeological wood samples at Kültepe and Acemhöyük in Turkey, and offer the potential to resolve this long-running problem. Here we show that previous work using tree-ring dating to place these timbers in absolute time has fundamental problems with key dendrochronological crossdates due to small sample numbers in overlapping years and insufficient critical assessment. To address, we have integrated secure dendrochronological sequences directly with radiocarbon (14C measurements to achieve tightly resolved absolute (calendar chronological associations and identify the secure links of this tree-ring chronology with the archaeological-historical evidence. The revised tree-ring-sequenced 14C time-series for Kültepe and Acemhöyük is compatible only with the so-called Middle Chronology and not with the rival High, Low or New Chronologies. This finding provides a robust resolution to a century of uncertainty in Mesopotamian chronology and scholarship, and a secure basis for construction of a coherent timeframe and history across the Near East and East Mediterranean in the earlier second millennium BCE. Our re-dating also affects an unusual tree-ring growth anomaly in wood from Porsuk, Turkey, previously tentatively associated with the Minoan eruption of the Santorini volcano. This tree-ring growth anomaly is now directly dated ~1681-1673 BCE (68.2% highest posterior density

  2. Ensemble empirical mode decomposition as a tool of lake sediments and tree-ring width chronologies investigation

    Science.gov (United States)

    Ovchinnikov, Dmitriy; Mordvinov, Alexandr; Kalugin, Ivan; Darin, Andrey; Myglan, Vladimir

    2014-05-01

    A method named ensemble empirical mode decomposition (EEMD) was used to analyse different paleoclimatic data such as non-varved lake sediments of the Teletskoye lake and long tree-ring width chronologies from the Altai region (Altai Mountains, South Siberia, Russia) in the late Holocene (2000 years). Core of the bottom sediments from the Teletskoe lake (Altai Mountains) were investigated using scanning X-ray fluorescent analysis method with synchrotron radiation (spatial resolution is 0.1 mm). Low-frequency signals (modes) were extracted from both paleoarchives and shown: ~ 60, ~ 100, ~ 200, ~ 300-500 and ~1000-year cycles in the Teletskoye lake; ~ 25-33, ~ 50-60, ~100- 200, ~ 300 and ~ 1000 year cycles in tree-ring width chronologies. A common 200-year cycle was found in both archives. Also EEMD method was used to analyse a solar-activity during late Holocene. The magnetic solar activity well associated with tree-ring width chronologies. Changes of the tree-ring width chronology on the millennial time scale coincide with similar changes of the solar activity in the Holocene. Stable relationships between solar activity and climate characteristics are found on 100-200 years time scales (Glaysberg and Suess cycles). The magnetic solar activity and paleotemperature changes are observed as solar-terrestrial relations on a large time scale. It is indicate that the temperature increase in the 19-20 centuries is largely due to the impact of solar activity on the Earth's climate system. Solar-terrestrial relations analysis shown common 200-year cycle in all presented paleoarchives. The study was funded by: Interdisciplinary Integration Project SB RAS # 34 and grants # 13-05-00620 from the Russian Foundation for Basic Research. Key words: ensemble empirical mode decomposition (EEMD), lake sediments, tree-ring width chronologies, solar-terrestrial relations

  3. Life-spanning murine gene expression profiles in relation to chronological and pathological aging in multiple organs

    Science.gov (United States)

    Kuiper, Raoul V; van der Hoeven, Tessa V; Wackers, P.F.K.; Robinson, Joke; van der Horst, Gijsbertus TJ; Dollé, Martijn ET; Vijg, Jan; Breit, Timo M; Hoeijmakers, Jan HJ; van Steeg, Harry

    2013-01-01

    Summary Aging and age-related pathology is a result of a still incompletely-understood intricate web of molecular and cellular processes. We present a C57BL/6J female mice in vivo aging study of five organs (liver, kidney, spleen, lung and brain), in which we compare genome-wide gene expression profiles during chronological aging with pathological changes throughout the entire murine lifespan (13, 26, 52, 78, 104 and 130 weeks). Relating gene expression changes to chronological aging revealed many differentially expressed genes (DEGs) and altered gene-sets (AGSs) were found in most organs, indicative of intra-organ generic aging processes. However, only ≤ 1% of these DEGs are found in all organs. For each organ, at least one of 18 tested pathological parameters showed a good age-predictive value, albeit with much inter- and intra-individual (organ) variation. Relating gene expression changes to pathology-related aging revealed correlated genes and gene-sets, which made it possible to characterize the difference between biological and chronological aging. In liver, kidney and brain, a limited number of overlapping pathology-related AGSs were found. Immune responses appeared to be common, yet the changes were specific in most organs. Furthermore, changes were observed in energy homeostasis, reactive oxygen species, cell cycle, cell motility and DNA damage. Comparison of chronological and pathology-related AGSs revealed substantial overlap and interesting differences. For example, the presence of immune processes in liver pathology-related AGSs which were not detected in chronological aging. The many cellular processes that are only found employing aging–related pathology could provide important new insights into the progress of aging. PMID:23795901

  4. An optimized multi-proxy, multi-site Antarctic ice and gas orbital chronology (AICC2012: 120–800 ka

    Directory of Open Access Journals (Sweden)

    H. Fischer

    2012-11-01

    Full Text Available An accurate and coherent chronological framework is essential for the interpretation of climatic and environmental records obtained from deep polar ice cores. Until now, one common ice core age scale has been developed based on an inverse dating method (Datice combining glaciological modelling with absolute and stratigraphic markers between 4 ice cores covering the last 50 ka (thousand of years before present (Lemieux-Dudon et al., 2010. In this paper, together with the companion paper of Veres et al. (2012, we present an extension of this work back to 800 ka for the NGRIP, TALDICE, EDML, Vostok and EDC ice cores using an improved version of the Datice tool. The AICC2012 (Antarctic Ice Core Chronology 2012 chronology includes numerous new gas and ice stratigraphic links as well as improved evaluation of background and associated variance scenarios. This paper concentrates on the long timescales between 120–800 ka. In this frame, new measurements of δ18Oatm over Marine Isotope Stage (MIS 11–12 on EDC and a complete δ18Oatm record of the TALDICE ice cores permit us to derive new orbital gas age constraints. The coherency of the different orbitally deduced ages (from δ18Oatm, δO2/N2 and air content has been verified before implementation in AICC2012. The new chronology shows only small differences, well within the original uncertainty range, when compared with the previous ice core reference age scale EDC3. For instance, the duration of the last four interglacial periods is not affected by more than 5%. The largest deviation between AICC2012 and EDC3 (4.4 ka is obtained around MIS 12. Despite significant modifications of the chronological constraints around MIS 5, now independent of speleothem records in AICC2012, the date of Termination II is very close to the EDC3 one.

  5. Tephra Deposits in Lake Mead Miocene Sediments: Characteristics, Chronology, and Sources

    Science.gov (United States)

    Dunbar, N. W.; McIntosh, W. C.; Umhoefer, P. J.; Lamb, M. A.; Hickson, T.

    2013-12-01

    The Lake Mead extensional domain, in the east central Basin and Range Province, contains Miocene basin sediments that have undergone complex faulting and deformation. A rich tephra record in the basin sediments provides a chronological and correlation framework that can help understand the depositional and deformational processes during Miocene and post-Miocene time. The tephra layers, up to 10s of cm thick, range from white deposits containing glassy shards to bright green layers in which all original glass has been altered to the zeolite mordenite. The tephra layers range from aphyric to extremely crystal rich. Many appear to be primary ashfall deposits based on depositional geometry, uniform crystal size, and good preservation of glass or relict glass shard structures. However, some layers show evidence of reworking as evidenced by variable crystal size, and the presence of plutonic feldspar and rock fragments. Electron microprobe analyses of preserved glass reveal that compositions of almost all of the tephra layers are high silica rhyolite, typically with FeO and CaO contents of 1wt% or lower. Where present, the glass in the tephra layers is invariably hydrated, consistent with their age, but although the alkali concentrations in the glass are likely to have been modified by the hydration process, other elements, particularly Fe, Ca, Ti, and Cl appear to yield robust concentrations. The compositions of individual layers with respect to these elements are very homogeneous, based on analysis of 20-30 glass shards per sample, and can be used to correlate individual tephra layers between different parts of the sedimentary basin, although a number of layers have very similar compositions. Some higher Fe rhyolites/dacites (up to 4 wt.% FeO) are also observed. Crystal-bearing tephra layers contain some combination of quartz, one or two feldspars (typically a chemically uniform sanidine and a range of plagioclase compositions), biotite, amphibole, and magnetite

  6. New constraining datasets for Eurasian ice sheet modelling: chronology, fjords and bedrock

    Science.gov (United States)

    Gyllencreutz, R.; Tarasov, L.; Mangerud, J.; Svendsen, J. I.; Lohne, Ø. S.

    2009-04-01

    The increasing resolution of ice sheet models demands more detailed data for constraining and for comparison of results. Important data for this include ice sheet chronology, bed conditions and topography. We address this by compiling published data into three new constraining data sets. The Eurasian ice sheet chronology is reconstructed in our database-GIS solution (called DATED; Gyllencreutz et al., 2007). In DATED, we are building a database with all available dates, and a GIS with all geomorphologic features, that are relevant for the ice configuration through the Last Glacial Maximum and the following deglaciation, based on results from the literature. Reconstructions of the ice sheet configuration are presented as thousand-year time slices of the advance and decay of the Eurasian ice sheet between 25 and 10 thousand calendar years ago, based on chronologic, geomorphologic and stratigraphic data from the literature. To facilitate handling of error estimates in ice sheet modeling using our reconstructions, we made three reconstructions for every time slice: a maximum, a minimum and a "probable" ice sheet configuration, based on the limitations of the data at hand. The estimated uncertainty for the reconstructions was calculated in the GIS, and amounts to about 1 million km2 (about 1/5 of the maximum area) for most of the record before the Younger Dryas, indicating significant gaps in the knowledge of the Eurasian ice sheet configuration. In order to facilitate modeling of fast ice flow and ice streams, we compiled information about exposed bedrock from digital Quaternary maps in scale 1:1 million by the geological surveys in Norway, Sweden, Finland, UK and Ireland, together with published drift thickness estimates. The bed conditions data set was generalized to a grid resolution of 0.25 x 0.25 degrees. The Norwegian fjords are important for topographic steering; especially for fast glacier flow and draw-down from more central parts of the ice sheet. However

  7. A Lower Rhine flood chronology based on the sedimentary record of an abandoned channel fill

    Science.gov (United States)

    Toonen, W. H. J.; Winkels, T. G.; Prins, M. A.; de Groot, L. V.; Bunnik, F. P. M.; Cohen, K. M.

    2012-04-01

    The Bienener Altrhein is an abandoned channel of the Lower Rhine (Germany). Following a late 16th century abandonment event, the channel was disconnected from the main stream and the oxbow lake gradually filled with 8 meters of flood deposits. This process still continues today. During annual floods, a limited proportion of overbank discharge is routed across the oxbow lake. Large floods produce individual flood layers, which are visually recognized in the sedimentary sequence. Based on the sedimentary characteristics of these event layers, we created a ~450-year flood chronology for the Lower Rhine. Laser-diffraction grain size measurements were used to assess relative flood magnitudes for individual flood event layers. Continuous sampling at a ~2 cm interval provided a high-resolution record, resolving the record at an annual scale. Standard descriptive techniques (e.g., mean grain size, 95th percentile, % sand) and the more advanced 'end member modelling' were applied to zoom in on the coarse particle bins in the grain size distributions, which are indicative of higher flow velocities. The most recent part of the record was equated to modern discharge measurements. This allows to establish relations between deposited grain size characteristics in the abandoned channel and flood magnitudes in the main river. This relation can also be applied on flood event layers from previous centuries, for which only water level measurements and historical descriptions exist. This makes this method relevant to expand data series used in flood frequency analysis from 100 years to more than 400 years. To date event-layers in the rapidly accumulated sequence, we created an age-depth model that uses organic content variations to tune sedimentation rates between the known basal and top ages. No suitable identifiable organic material for radiocarbon dating was found in the cores. Instead, palynological results (introduction of agricultural species) and palaeomagnetic secular

  8. Chronology of Pu isotopes and {sup 236}U in an Arctic ice core

    Energy Technology Data Exchange (ETDEWEB)

    Wendel, C.C., E-mail: cato.wendel@umb.no [Isotope Laboratory, Department of Plant and Environmental Sciences, Agricultural University of Norway, P.O. Box 5003, N-1432 Aas (Norway); Oughton, D.H., E-mail: deborah.oughton@umb.no [Isotope Laboratory, Department of Plant and Environmental Sciences, Agricultural University of Norway, P.O. Box 5003, N-1432 Aas (Norway); Lind, O.C., E-mail: ole-christian.lind@umb.no [Isotope Laboratory, Department of Plant and Environmental Sciences, Agricultural University of Norway, P.O. Box 5003, N-1432 Aas (Norway); Skipperud, L., E-mail: lindis.skipperud@umb.no [Isotope Laboratory, Department of Plant and Environmental Sciences, Agricultural University of Norway, P.O. Box 5003, N-1432 Aas (Norway); Fifield, L.K., E-mail: keith.fifield@anu.edu.au [Department of Nuclear Physics, Australian National University, Canberra ACT 0200 (Australia); Isaksson, E., E-mail: elisabeth.isaksson@npolar.no [Norwegian Polar Institute, Fram Centre, Hjalmar Johansens Gate 14, N9296 Tromsø (Norway); Tims, S.G., E-mail: steve.tims@anu.edu.au [Department of Nuclear Physics, Australian National University, Canberra ACT 0200 (Australia); Salbu, B., E-mail: brit.salbu@umb.no [Isotope Laboratory, Department of Plant and Environmental Sciences, Agricultural University of Norway, P.O. Box 5003, N-1432 Aas (Norway)

    2013-09-01

    In the present work, state of the art isotopic fingerprinting techniques are applied to an Arctic ice core in order to quantify deposition of U and Pu, and to identify possible tropospheric transport of debris from former Soviet Union test sites Semipalatinsk (Central Asia) and Novaya Zemlya (Arctic Ocean). An ice core chronology of {sup 236}U, {sup 239}Pu, and {sup 240}Pu concentrations, and atom ratios, measured by accelerator mass spectrometry in a 28.6 m deep ice core from the Austfonna glacier at Nordaustlandet, Svalbard is presented. The ice core chronology corresponds to the period 1949 to 1999. The main sources of Pu and {sup 236}U contamination in the Arctic were the atmospheric nuclear detonations in the period 1945 to 1980, as global fallout, and tropospheric fallout from the former Soviet Union test sites Novaya Zemlya and Semipalatinsk. Activity concentrations of {sup 239+240}Pu ranged from 0.008 to 0.254 mBq cm{sup −2} and {sup 236}U from 0.0039 to 0.053 μBq cm{sup −2}. Concentrations varied in concordance with {sup 137}Cs concentrations in the same ice core. In contrast to previous published results, the concentrations of Pu and {sup 236}U were found to be higher at depths corresponding to the pre-moratorium period (1949 to 1959) than to the post-moratorium period (1961 and 1962). The {sup 240}Pu/{sup 239}Pu ratio ranged from 0.15 to 0.19, and {sup 236}U/{sup 239}Pu ranged from 0.18 to 1.4. The Pu atom ratios ranged within the limits of global fallout in the most intensive period of nuclear atmospheric testing (1952 to 1962). To the best knowledge of the authors the present work is the first publication on biogeochemical cycles with respect to {sup 236}U concentrations and {sup 236}U/{sup 239}Pu atom ratios in the Arctic and in ice cores. - Highlights: • Concentrations and atom ratios of Pu and {sup 236}U determined in an Arctic ice core. • Concentrations of U and Pu found to be higher pre- than post-moratorium. • U and Pu concentrations

  9. Middle to Late Pleistocene coastal deposits of Eivissa (Western Mediterranean): Chronology and evolution.

    Science.gov (United States)

    Del Valle, Laura; Pomar, Francisco; Fornós, Joan J.; Gómez-Pujol, Lluís; Anechitei-Deacu, Valentina; Timar-Gabor, Alida

    2016-04-01

    This study deals with the sedimentary and stratigraphical description of Pleistocene deposits from seven coastal areas of Eivissa (Balearic Islands). Twenty two sedimentary facies have been described involving the succession of eolian, colluvial and edaphic environments. Carbonate sandstones, breccias and silty deposits are the main component of these sequences. Despite the extensive eolian systems outcropping along the coast of Eivissa, there are very few studies performed to chronological framework of these deposits. Luminescence measurements were carried out using an automated RisØ TL/OSL-DA-20 reader in the Luminescence Dating Laboratory of Babes-Bolyai University (Cluj-Napoca, Romania) under low intensity red light. OSL dating of nineteen eolian levels indicate that their deposition took place between the Middle and Late Pleistocene, establishing a paleoclimatic evolution of Eivissa Island since 755 ka to 70 Ka. Eolian activity in the Eivissa Island can be correlated with regression episodes which took place during cold periods associated with different isotopic stages, concretely the MIS 18, 16, 12, 10, 8, 6 and 4. Similar results have been obtained from many sites along the western Mediterranean Sea such as Mallorca (Pomar i Cuerda, 1979; Nielsen et al, 2004; Fornós et al, 2009), Sardinia (Andreucci et al, 2009; Pascucci et al, 2014), Liguria (Pappalardo et al., 2013). Keywords: Eolian dunes, Pleistocene, Climatic evolution, Eivissa. References - Andreucci, S.; Pascucci, V.; Murray, A. S.; Clemmensen, L. B. 2009. Late Pleistocene coastal evolution of San Giovanni di Sinis, west Sardinia (Western Mediterranean). Sedimentary Geology, 216: 104- 116 - Fornós, J.J.; Clemmensen, L.B.; Gómez-Pujol, L.; Murray, A. 2009. Late Pleistocene carbonate aeolianites on Mallorca, Western Mediterranean: a luminescence chronology. Quaternary Science reviews 28: 2697-2709. -Nielsen, K.A.; Clemmensen, L.B.; Fornós, J.J. 2004. Middle Pleistocene magnetostratigraphy and

  10. Glacial chronology and palaeoclimate in the Bystra catchment, Western Tatra Mountains (Poland) during the Late Pleistocene

    Science.gov (United States)

    Makos, Michał; Rinterknecht, Vincent; Braucher, Régis; Żarnowski, Michał

    2016-02-01

    Deglaciation chronology of the Bystra catchment (Western Tatra Mountains) has been reconstructed based on 10Be exposure age dating. Fourteen rock samples were collected from boulders located on three moraines that limit the horizontal extent of the LGM maximum advance and the Lateglacial recessional stage. The oldest preserved, maximum moraine was dated at 15.5 ± 0.8 ka, an age that could be explained more likely by post-depositional erosion of the moraine. Such scenario is supported by geomorphologic and palaeoclimatological evidence. The younger cold stage is represented by well-preserved termino-lateral moraine systems in the Kondratowa and Sucha Kasprowa valleys. The distribution of the moraine ridges in both valleys suggest a complex history of deglaciation of the area. The first Late-glacial re-advance (LG1) was followed by a cold oscillation (LG2), that occurred at around 14.0 ± 0.7-13.7 ± 1.2 ka. Glaciers during both stages had nearly the same horizontal extent, however, their thickness and geometry changed significantly, mainly due to local climatic conditions triggered by topography, controlling the exposition to solar radiation. The LG1 stage occurred probably during the pre-Bølling cold stage (Greenland Stadial 2.1a), however, the LG2 stage can be correlated with the cooling at around 14 ka during the Greenland Interstadial 1 (GI-1d - Older Dryas). This is the first chronological evidence of the Older Dryas in the Tatra Mountains. The ELA of the maximum Bystra glacier was located at 1480 m a.s.l. in accordance with the ELA in the High Tatra Mountains during the LGM. During the LG1 and LG2 stages, the ELA in the catchment rose up to 1520-1530 m a.s.l. and was located approximately 100-150 m lower than in the eastern part of the massif. Climate modelling results show that the Bystra glacier (maximum advance) could have advanced in the catchment when mean annual temperature was lower than today by 11-12 °C and precipitation was reduced by 40-60%. This

  11. A query on the year of King Wu's conquest over King Zhou determined by the Xia- Shang-Zhou Chronology Project ——Materials finding and astronomical methods for chronological studies of China

    Institute of Scientific and Technical Information of China (English)

    李勇

    2003-01-01

    This paper reviews the studies on the event that King Wu of the Western Zhou Dynasty defeated King Zhou of the late Shang Dynasty, an important historical event in Chinese history, and questions on the year in which this event took place determined by researchers of the Xia-Shang-Zhou Chronology Project of China in 2000. This paper also discusses on how to obtain primordial materials and how to use astronomical methods in the chronological studies of Chinese history. With both the new astronomical methods (the Moon Age Calendar Method and the Direct Solving Method) and the calculation based on the confirmed real-time materials, especially scriptures on oracle bones and bronze vessels, this paper obtains a more accurate and reliable result, putting the event at BC 1040 to BC 1030.

  12. Mitochondrial dysfunction increases oxidative stress and decreases chronological life span in fission yeast.

    Directory of Open Access Journals (Sweden)

    Alice Zuin

    Full Text Available BACKGROUND: Oxidative stress is a probable cause of aging and associated diseases. Reactive oxygen species (ROS originate mainly from endogenous sources, namely the mitochondria. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed the effect of aerobic metabolism on oxidative damage in Schizosaccharomyces pombe by global mapping of those genes that are required for growth on both respiratory-proficient media and hydrogen-peroxide-containing fermentable media. Out of a collection of approximately 2700 haploid yeast deletion mutants, 51 were sensitive to both conditions and 19 of these were related to mitochondrial function. Twelve deletion mutants lacked components of the electron transport chain. The growth defects of these mutants can be alleviated by the addition of antioxidants, which points to intrinsic oxidative stress as the origin of the phenotypes observed. These respiration-deficient mutants display elevated steady-state levels of ROS, probably due to enhanced electron leakage from their defective transport chains, which compromises the viability of chronologically-aged cells. CONCLUSION/SIGNIFICANCE: Individual mitochondrial dysfunctions have often been described as the cause of diseases or aging, and our global characterization emphasizes the primacy of oxidative stress in the etiology of such processes.

  13. Paleoseismic investigations in the Kopili Fault Zone of North East India: Evidences from liquefaction chronology

    Science.gov (United States)

    Kumar, Devender; Reddy, D. V.; Pandey, Anand K.

    2016-04-01

    We report the seismogenic liquefaction signatures observed in the Kopili Fault Zone of the Brahmaputra plains, NE India. This seismically active zone has previously been identified as the "Assam seismic gap" and thus necessitates understanding its past seismicity and implied seismic hazard. With this objective, paleo-seismic studies using seismogenic liquefaction features have been carried out in this region largely covered with the flood plain deposits of Kopili and Kalang rivers. The trenches excavated at two locations revealed extensive liquefaction features with more than 20 sub parallel sand dykes having major orientation in NE-SW direction. A total of 29 samples from marker horizons have been processed to constrain chronology of the liquefaction features using optically stimulated luminescence (OSL) and 14C (AMS) dating techniques. The age constraints in terms of respective lower and upper bound age brackets for individual dykes suggest three time intervals of their formations i.e. (i) 250 ± 25 yr. BP, (ii) between 400 to 770 yr. BP and (iii) 900 ± 50 yr. BP. These new ages of liquefaction features correspond to the occurrence timings of causative seismic events which are in addition to the known historical earthquakes and thus enhance our understanding of the paleoseismic history of this region during past ~ 1000 years.

  14. The Byzantine titles of Jovan Oliver: A contribution to the issues of their origin and chronology

    Directory of Open Access Journals (Sweden)

    Pirivatrić Srđan

    2013-01-01

    Full Text Available The inscription by the portrait of Jovan Oliver, the founder, in the main church of monastery Lesnovo, contains the earliest data on high Byzantine court dignities he held. The founder is portrayed invested as a sebastokrator, the inscription is written over an older one which it partially repeats and gives the information on the two Byzantine titles of Jovan Oliver: in the first part of the inscription there is reference on his title of sebastokrator “in Serbs”, while in the second part he is mentioned with the title of despotes “of all Serbian and maritime regions and učestnik (sc. particeps of Greeks”. In the inscription both of the dignities are connected with the king Stefan Dušan. The analysis of the data of the founder’s inscription, when put into the context of the civil war that lasted in Byzantium from 1341 to 1347, enables the conclusions on the exact Byzantine origin of his titles and approximate chronology of his investment. [Projekat Ministarstva nauke Republike Srbije, br. 177032: Tradicija, inovacija i identitet u vizantijskom svetu

  15. The origin and chronology of medieval silver coins based on the analysis of chemical composition

    Directory of Open Access Journals (Sweden)

    Pańczyk Ewa

    2015-09-01

    Full Text Available Medieval Central Europe coins - the Saxon coins, also called as the Otto and Adelheid denarii, as well as the Polish ones, the Władysław Herman and Bolesław Śmiały coins - were examined to determine their provenance and dating. Their attribution and chronology often constitute a serious problem for historians and numismatists. For hundreds of years, coins were in uncontrolled conditions and in variable environment. Destructed and inhomogeneous surface were the effect of corrosion processes. Electron microscopy with energy dispersive X-ray analysis (scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS, X-ray fluorescence (XRF analysis (energy dispersive X-ray fluorescence (EDXRF and total reflection X-ray fluorescence (TXRF, and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS were applied. The results of these investigations are significant for our knowledge of the history of Central European coinage, especially of Polish coinage

  16. Application of OSL and 10Be techniques to the establishment of deglaciation chronology in Estonia

    International Nuclear Information System (INIS)

    The deglaciation history of Estonia has been under research for about a century. Despite the great number of publications devoted to this subject and marked improvements in study methods, many problems of topical interest have not been solved yet, especially due to the lack of good direct dating methods. In this paper the suitability of OSL and 10Be dating techniques for establishing accurate deglaciation chronology for Estonia is assessed. Turbidity and water depth, velocity of outwash streams and transport length, possible fast sedimentation at night hours or below the ice, incorporation of older, unbleached particles, and other factors affected the extent of the bleaching of the TL signal in different ways, causing great variability of dates. Surface inclination, height of the surface over ground, snow and vegetation cover, and evolution of water bodies influenced the calculation of reliable exposure ages of objects dated using the 10Be method. It means that age determinations of both glaciofluvial deposits with the OSL method and erratic boulders with the 1Be method are highly problematic, especially for glaciofluvial intertill sediments where the exact genesis of deposits is unknown and for boulders, which have been in the forest, under the waters of proglacial lakes and/or the Baltic Sea, or under snow cover for a long time. (author)

  17. Application of tandem accelerator mass spectrometor to the chronological study of archaeological samples on Ryukyu Islands

    Energy Technology Data Exchange (ETDEWEB)

    Taira, Hatsuo; Higa, Kenichi; Nakai, Nobuyuki; Nakamura, Toshio.

    1987-10-01

    Along with the urbanization of rural areas on Ryukyu Islands, many shell mounds and pre-historic sites have been found in resent years. Chrological studies of shell samples from these mounds will lead to the better understanding of cultural background for the pre-historic human activities on the Ryukyu Islands. C-14 dating by beta counting is the common method to obtain the ages of the archaeological samples. It is, however, very limited in obtaining the absolute ages by the above mehtod due to the large sample sizes required and time consuming. There are many newly obtained archaeological samples left unstudied in detail. The alternate is a method called Tandem Accelerator Mass Spectrometer (AMS) installed at Nagoya University, which is composed of the tandem type accelerator to measure very low concentration of C-14 in archaeological samples. The system has been designed particularly to measure the radio-carbon and has advantages of being small sample size and very little time consuming for C-14 measurement as compared with the beta counting. It is the aim of this work to apply the above AMS for obtaining the absolute ages of the archaeological samples. The results agreed well with those estimated by the Erthenware method (relative method of dating), which ranged from 500 to 6000 y.b.p. The results may be helpful for the chronological arrangement of the samples and for the understanding of pre-historical human activities on the Ryukyu Islands.

  18. Chronology of the stratum containing the skull of the Dali Man

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The field investigations of geomorphology and Quaternary sediment sequences show that the sediment stratigraphic profile containing the skull of the Homo sapiens Daliensis (Dali Man) at Tianshuigou trench, Jiefang Village (109°44′E, 34°52′N ), Dali County, Shaanxi Province, is composed of the loess-paleosol sequence, 17.3 m thick, in the upper part, and the alluvial silts, fine sands and sandy gravels interbedded, 15.4 m thick, in the lower part. There are the well developed layers L1, S1, L2 and S2 in the loess-paleosol sequence of the profile, which are comparable to those of the Luochuan loess section on the basis of magnetic succeptibility measurements and IRSL dating of the loess samples. An alluvial gravel layer, where the skull of the Dali Man was discovered, is in 13 m beneath the bottom of paleosol S2, implying that, the age of the Dali Man must be older than about 247 kaBP when the paleosol S2 began to be developed. The samples of mammal animal tooth and shell fossils from the gravel layer containing the skull of the Dali Man have been dated by uranium series and ESR methods respectively. Based on the multiple dating results and the stratigraphic chronology, the age of the Dali Man, therefore, would be estimated as older than 250 kaBP and younger than 350 kaBP, and reasonably estimated as 260-300 kaBP.

  19. Importance of the Lu-Hf isotopic system in studies of planetary chronology and chemical evolution

    Science.gov (United States)

    Patchett, P. J.

    1983-01-01

    The Lu-176-Hf-176 isotope method and its applications in earth sciences are discussed with regard to planetary-evolution studies. From new data on basalts from oceanic islands, Hf-176/Hf-177 and Nd-143/Nd-144 are found to display a single linear isotopic variation in the suboceanic mantle, whereas considerable divergences occur in Hf-176/Hf-177-Sr-87/Sr-86 and Nd-143/Nd-144-Sr87/Sr-86 diagrams. With the acquisition of further Hf-Sr-Nd isotopic data, these discordant Sr-87/Sr-86 relationships may allow a distinction between processes such as mantle metasomatism, influence of sea-water altered material in the magma source, or recycling of sediments into the mantle. The best quality Hf isotope data are obtained from granitoid or zircons, and are most suitable for studying ancient terrestrial Hf isotopic variations. Lu-Hf is shown to be a viable method for dating ancient terrestrial and extraterrestrial samples, but is unlikely to find wide application in pure chronological studies because it offers little advantage over existing methods.

  20. Oxygen availability strongly affects chronological lifespan and thermotolerance in batch cultures of Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Markus M.M. Bisschops

    2015-10-01

    Full Text Available Stationary-phase (SP batch cultures of Saccharomyces cerevisiae, in which growth has been arrested by carbon-source depletion, are widely applied to study chronological lifespan, quiescence and SP-associated robustness. Based on this type of experiments, typically performed under aerobic conditions, several roles of oxygen in aging have been proposed. However, SP in anaerobic yeast cultures has not been investigated in detail. Here, we use the unique capability of S. cerevisiae to grow in the complete absence of oxygen to directly compare SP in aerobic and anaerobic bioreactor cultures. This comparison revealed strong positive effects of oxygen availability on adenylate energy charge, longevity and thermotolerance during SP. A low thermotolerance of anaerobic batch cultures was already evident during the exponential growth phase and, in contrast to the situation in aerobic cultures, was not substantially increased during transition into SP. A combination of physiological and transcriptome analysis showed that the slow post-diauxic growth phase on ethanol, which precedes SP in aerobic, but not in anaerobic cultures, endowed cells with the time and resources needed for inducing longevity and thermotolerance. When combined with literature data on acquisition of longevity and thermotolerance in retentostat cultures, the present study indicates that the fast transition from glucose excess to SP in anaerobic cultures precludes acquisition of longevity and thermotolerance. Moreover, this study demonstrates the importance of a preceding, calorie-restricted conditioning phase in the acquisition of longevity and stress tolerance in SP yeast cultures, irrespective of oxygen availability.

  1. Synchronizing ice cores from the Renland and Agassiz ice caps to the Greenland Ice Core Chronology

    DEFF Research Database (Denmark)

    Vinther, Bo Møllesøe; Clausen, Henrik Brink; Fischer, D. A.;

    2008-01-01

    Four ice cores from the Agassiz ice cap in the Canadian high arctic and one ice core from the Renland ice cap in eastern Greenland have been synchronized to the Greenland Ice Core Chronology 2005 (GICC05) which is based on annual layer counts in the DYE-3, GRIP and NGRIP ice cores. Volcanic...... reference horizons, seen in electrical conductivity measurements (ECM) have been used to carry out the synchronization throughout the Holocene. The Agassiz ice cores have been matched to the NGRIP ice core ECM signal, while the Renland core has been matched to the GRIP ice core ECM signal, thus tying...... the cores to GICC05. Furthermore, it has been possible to synchronize the Renland ice core to NGRIP-GICC05 in the glacial period back to 60,000 years b2k (years before A.D. 2000), on the basis of a matching of transitions between stadials and interstadials. This work brings the total number of ice core...

  2. Revised stratigraphy and chronology for Homo floresiensis at Liang Bua in Indonesia.

    Science.gov (United States)

    Sutikna, Thomas; Tocheri, Matthew W; Morwood, Michael J; Saptomo, E Wahyu; Jatmiko; Awe, Rokus Due; Wasisto, Sri; Westaway, Kira E; Aubert, Maxime; Li, Bo; Zhao, Jian-xin; Storey, Michael; Alloway, Brent V; Morley, Mike W; Meijer, Hanneke J M; van den Bergh, Gerrit D; Grün, Rainer; Dosseto, Anthony; Brumm, Adam; Jungers, William L; Roberts, Richard G

    2016-04-21

    Homo floresiensis, a primitive hominin species discovered in Late Pleistocene sediments at Liang Bua (Flores, Indonesia), has generated wide interest and scientific debate. A major reason this taxon is controversial is because the H. floresiensis-bearing deposits, which include associated stone artefacts and remains of other extinct endemic fauna, were dated to between about 95 and 12 thousand calendar years (kyr) ago. These ages suggested that H. floresiensis survived until long after modern humans reached Australia by ~50 kyr ago. Here we report new stratigraphic and chronological evidence from Liang Bua that does not support the ages inferred previously for the H. floresiensis holotype (LB1), ~18 thousand calibrated radiocarbon years before present (kyr cal. BP), or the time of last appearance of this species (about 17 or 13-11 kyr cal. BP). Instead, the skeletal remains of H. floresiensis and the deposits containing them are dated to between about 100 and 60 kyr ago, whereas stone artefacts attributable to this species range from about 190 to 50 kyr in age. Whether H. floresiensis survived after 50 kyr ago--potentially encountering modern humans on Flores or other hominins dispersing through southeast Asia, such as Denisovans--is an open question.

  3. The EDC3 chronology for the EPICA Dome C ice core

    Directory of Open Access Journals (Sweden)

    F. Parrenin

    2007-03-01

    Full Text Available The EPICA (European Project for Ice Coring in Antarctica Dome C drilling in East Antarctica has now been completed to a depth of 3260 m, at only a few meters above bedrock. Here we present the new official EDC3 chronology, which is based on the use of 1 a snow accumulation and mechanical flow model, and 2 a set of independent age markers along the core. These are obtained by pattern matching of recorded parameters to either absolutely dated paleoclimatic records, or to insolation variations. We show that this new time scale is in excellent agreement with the Dome Fuji and Vostok ice core time scales back to 100 kyr within 1 kyr. Discrepancies larger than 3 kyr arise during MIS 5.4, 5.5 and 6, which points to anomalies in either snow accumulation or mechanical flow during these time periods. We estimate that EDC3 gives accurate event durations within 20% (2σ back to MIS11 and accurate absolute ages with a maximum uncertainty of 6 kyr back to 800 kyr.

  4. Chronology and Nutrients Change in Recent Sediment of Taihu Lake, Lower Changjiang River Basin, East China

    Institute of Scientific and Technical Information of China (English)

    YAO Shuchun; XUE Bin; KONG Deyang

    2010-01-01

    Two short sediment cores named ZS and THS dated by the 210Pb or 137Cs method were collected from the northwest and southwest of Taihu Lake respectivly, and total organic carbon (TOC) and nutrients including total nitrogen (TN) and total phosphorus (TP) were determined to analyze the chronology and nutrients change in recent sediment. The results show that 137Cs activities are low (less than 15 Bq/kg) in the two cores, attributed to the 137Cs migration. Based on 210Pb constant rate of supply (CRS) model, the sedimentation accumulation rates range from 0.13 increase in organic matter and nutrients has occurred in the two dated cores since the mid-1980s. The historical changes of organic matter and nutrients in the two cores are consisitent with the monitoring data for surface sediment after the 1960s. The TP accumulation rates after the early 1980s are 0.97 and 0.92 times higher than those from the 1950s to the 1980s in ZS and THS cores, respectively. Higher TP concentrations in the past two-decade deposits of Taihu Lake are due to both diagenetic factors and human activities.

  5. Chronology of DIC technique based on the fundamental mathematical modeling and dehydration impact.

    Science.gov (United States)

    Alias, Norma; Saipol, Hafizah Farhah Saipan; Ghani, Asnida Che Abd

    2014-12-01

    A chronology of mathematical models for heat and mass transfer equation is proposed for the prediction of moisture and temperature behavior during drying using DIC (Détente Instantanée Contrôlée) or instant controlled pressure drop technique. DIC technique has the potential as most commonly used dehydration method for high impact food value including the nutrition maintenance and the best possible quality for food storage. The model is governed by the regression model, followed by 2D Fick's and Fourier's parabolic equation and 2D elliptic-parabolic equation in a rectangular slice. The models neglect the effect of shrinkage and radiation effects. The simulations of heat and mass transfer equations with parabolic and elliptic-parabolic types through some numerical methods based on finite difference method (FDM) have been illustrated. Intel®Core™2Duo processors with Linux operating system and C programming language have been considered as a computational platform for the simulation. Qualitative and quantitative differences between DIC technique and the conventional drying methods have been shown as a comparative. PMID:25477631

  6. An evaluation of third molar eruption for assessment of chronologic age: A panoramic study

    Directory of Open Access Journals (Sweden)

    Monica Tuteja

    2012-01-01

    Full Text Available Objectives: The identity of a person can be established by assessing one′s age, and in order to be entitled to civil rights and social benefits, verification of the chronological age is required and thereby age estimation has gained an increasing significance in recent years. Tooth eruption is one of the criteria of developmental morphology that can be evaluated by either clinical examination or by evaluation of dental radiographs to determine the dental age. The present study was aimed to evaluate the reliability of the third molar eruption stage as a parameter for forensic age estimation in living subjects. Materials and Methods: The stage of wisdom tooth eruption in 77 male and 73 female Indian subjects aged between 12-26 years was determined by subjecting them to conventional orthopantomograms and was interpreted to assess the third molar eruption stages to evaluate the dental age. Results: Predicted minimum age and mean age of the study sample were found to be significant predictors (P<0.001 of actual age. Minimum age was able to explain 58.3% of the variation in actual age and the mean age was able to explain 60.3% of variation in actual age. Conclusion: Third molar is fairly a reliable indicator to determine the age of alveolar, gingival, and complete emergence of third molar in the occlusal plane in adolescents and young adults. Minimum and most probable ages of examined subjects can also be evaluated using third molar eruption stage.

  7. Revised stratigraphy and chronology for Homo floresiensis at Liang Bua in Indonesia.

    Science.gov (United States)

    Sutikna, Thomas; Tocheri, Matthew W; Morwood, Michael J; Saptomo, E Wahyu; Jatmiko; Awe, Rokus Due; Wasisto, Sri; Westaway, Kira E; Aubert, Maxime; Li, Bo; Zhao, Jian-xin; Storey, Michael; Alloway, Brent V; Morley, Mike W; Meijer, Hanneke J M; van den Bergh, Gerrit D; Grün, Rainer; Dosseto, Anthony; Brumm, Adam; Jungers, William L; Roberts, Richard G

    2016-04-21

    Homo floresiensis, a primitive hominin species discovered in Late Pleistocene sediments at Liang Bua (Flores, Indonesia), has generated wide interest and scientific debate. A major reason this taxon is controversial is because the H. floresiensis-bearing deposits, which include associated stone artefacts and remains of other extinct endemic fauna, were dated to between about 95 and 12 thousand calendar years (kyr) ago. These ages suggested that H. floresiensis survived until long after modern humans reached Australia by ~50 kyr ago. Here we report new stratigraphic and chronological evidence from Liang Bua that does not support the ages inferred previously for the H. floresiensis holotype (LB1), ~18 thousand calibrated radiocarbon years before present (kyr cal. BP), or the time of last appearance of this species (about 17 or 13-11 kyr cal. BP). Instead, the skeletal remains of H. floresiensis and the deposits containing them are dated to between about 100 and 60 kyr ago, whereas stone artefacts attributable to this species range from about 190 to 50 kyr in age. Whether H. floresiensis survived after 50 kyr ago--potentially encountering modern humans on Flores or other hominins dispersing through southeast Asia, such as Denisovans--is an open question. PMID:27027286

  8. Glucose restriction induces transient G2 cell cycle arrest extending cellular chronological lifespan.

    Science.gov (United States)

    Masuda, Fumie; Ishii, Mahiro; Mori, Ayaka; Uehara, Lisa; Yanagida, Mitsuhiro; Takeda, Kojiro; Saitoh, Shigeaki

    2016-01-01

    While glucose is the fundamental source of energy in most eukaryotes, it is not always abundantly available in natural environments, including within the human body. Eukaryotic cells are therefore thought to possess adaptive mechanisms to survive glucose-limited conditions, which remain unclear. Here, we report a novel mechanism regulating cell cycle progression in response to abrupt changes in extracellular glucose concentration. Upon reduction of glucose in the medium, wild-type fission yeast cells undergo transient arrest specifically at G2 phase. This cell cycle arrest is dependent on the Wee1 tyrosine kinase inhibiting the key cell cycle regulator, CDK1/Cdc2. Mutant cells lacking Wee1 are not arrested at G2 upon glucose limitation and lose viability faster than the wild-type cells under glucose-depleted quiescent conditions, suggesting that this cell cycle arrest is required for extension of chronological lifespan. Our findings indicate the presence of a novel cell cycle checkpoint monitoring glucose availability, which may be a good molecular target for cancer therapy. PMID:26804466

  9. A calibrated chronology of biochemistry reveals a stem line of descent responsible for planetary biodiversity

    Directory of Open Access Journals (Sweden)

    Gustavo eCaetano-Anollés

    2014-09-01

    Full Text Available Time-calibrated phylogenomic trees of protein domain structure produce powerful chronologies describing the evolution of biochemistry and life. These timetrees are built from a genomic census of millions of encoded proteins using models of nested accumulation of molecules in evolving proteomes. Here we show that a primordial stem line of descent, a propagating series of pluripotent cellular entities, populates the deeper branches of the timetrees. The stem line produced for the first time cellular grades ~2.9 billion years (Gy-ago, which slowly turned into lineages of superkingdom Archaea. Prompted by the rise of planetary oxygen and aerobic metabolism, the stem line also produced bacterial and eukaryal lineages. Superkingdom-specific domain repertoires emerged ~2.1 Gy-ago delimiting fully diversified Bacteria. Repertoires specific to Eukarya and Archaea appeared 300 millions years later. Results reconcile reductive evolutionary processes leading to the early emergence of Archaea to superkingdom-specific innovations compatible with a tree of life rooted in Bacteria.

  10. From Suns to Life: A Chronological Approach to the History of Life on Earth

    CERN Document Server

    Gargaud, Muriel; López-García, Purificación; Martin, Hervé; Montmerle, Thierry; Pascal, Robert; Reisse, Jacques

    2006-01-01

    This review emerged from several interdisciplinary meetings and schools gathering a group of astronomers, geologists, biologists, and chemists, attempting to share their specialized knowledge around a common question: how did life emerge on Earth? Their ultimate goal was to provide some kind of answer as a prerequisite to an even more demanding question: is life universal? The resulting state-of-the-art articles were written by twenty-five scientists telling a not-so linear story, but on the contrary, highlighting problems, gaps, and controversies. Needless to say, this approach yielded no definitive answers to both questions. However, by adopting a chronological approach to the question of the emergence of life on Earth, the only place where we know for sure that life exists; it was possible to break down this question into several sub-topics that can be addressed by the different disciplines. The main chapters of this review present the formation and evolution of the solar system (3); the building of a habi...

  11. Chronological Changes of Quality of Life in Long-Term Survivors after Gastrectomy for Gastric Cancer

    Science.gov (United States)

    Yu, Wansik; Park, Ki Bum; Chung, Ho Young; Kwon, Oh Kyoung; Lee, Seung Soo

    2016-01-01

    Purpose A few studies have prospectively evaluated changes in quality of life (QoL) after surgery in short-term survivors; however, no prospective study has evaluated the longitudinal changes in QoL in long-terms survivors. We prospectively evaluated the chronological changes in QoL after a gastrectomy over a 5-year postoperative period in a large group of patients. Materials and Methods QoL data from the European Organization for Research and Treatment of Cancer QLQ-C30 and the QLQ-STO22 questionnaires were obtained from 254 patients who completed the entire series of QoL assessments preoperatively and at 1, 2, 3, 4, and 5 years after surgery. Results There was no statistically significant change in global health status/QoL during the 5-year postoperative period. Decreases in QoL from upper gastrointestinal symptoms including diarrhea (p physical functioning (p physical functioning, role functioning, and body image. In addition, patients should be encouraged to preserve self-esteem and maintain social activity. PMID:27004956

  12. An optical luminescence chronology for late Pleistocene aeolian activity in the Colombian and Venezuelan Llanos

    Science.gov (United States)

    Carr, Andrew S.; Armitage, Simon J.; Berrío, Juan-Carlos; Bilbao, Bibiana A.; Boom, Arnoud

    2016-03-01

    The lowland savannas (Llanos) of Colombia and Venezuela are covered by extensive aeolian landforms for which little chronological information exists. We present the first optically stimulated luminescence (OSL) age constraints for dunes in the Llanos Orientales of lowland Colombia and new ages for dunes in the Venezuelan Llanos. The sampled dunes are fully vegetated and show evidence of post-depositional erosion. Ages range from 4.5 ± 0.4 to 66 ± 4 ka, with the majority dating to 27-10 ka (Marine Isotope Stage 2). Some dunes accumulated quickly during the last glacial maximum, although most were active 16-10 ka. Accretion largely ceased after 10 ka. All dunes are elongated downwind from rivers, parallel with dry season winds, and are interpreted as source-bordering features. As they are presently isolated from fluvial sediments by gallery forest it is proposed that activity was associated with a more prolonged dry season, which restricted gallery forest, leading to greater sediment availability on river shorelines. Such variability in dry season duration was potentially mediated by the mean latitude of the ITCZ. The cessation of most dune accretion after ca. 10 ka suggests reduced seasonality and a more northerly ITCZ position, consistent with evidence from the Cariaco Basin.

  13. The EDC3 chronology for the EPICA Dome C ice core

    Directory of Open Access Journals (Sweden)

    F. Parrenin

    2007-08-01

    Full Text Available The EPICA (European Project for Ice Coring in Antarctica Dome C drilling in East Antarctica has now been completed to a depth of 3260 m, at only a few meters above bedrock. Here we present the new EDC3 chronology, which is based on the use of 1 a snow accumulation and mechanical flow model, and 2 a set of independent age markers along the core. These are obtained by pattern matching of recorded parameters to either absolutely dated paleoclimatic records, or to insolation variations. We show that this new time scale is in excellent agreement with the Dome Fuji and Vostok ice core time scales back to 100 kyr within 1 kyr. Discrepancies larger than 3 kyr arise during MIS 5.4, 5.5 and 6, which points to anomalies in either snow accumulation or mechanical flow during these time periods. We estimate that EDC3 gives accurate event durations within 20% (2σ back to MIS11 and accurate absolute ages with a maximum uncertainty of 6 kyr back to 800 kyr.

  14. Human consumption of Lepidoptera in Africa : an updated chronological list of references (370 quoted!) with their ethnozoological analysis

    OpenAIRE

    Malaisse, François; Latham, Paul

    2014-01-01

    Human consumption of insects or « lepidopterophagy » is becoming increasingly important. In the present paper 370 references dealing with this subject in Africa are quoted. Access to this information is provided both, by chronological and alphabetic order of authors. A systematic list of scientific names of edible Lepidoptera in Africa is also provided. The importance of the information available for various ethnolinguidstic groups is presented. The evolution of issues covered is analyzed and...

  15. Aligning MIS5 proxy records from Lake Ohrid (FYROM) with independently dated Mediterranean archives: implications for core chronology

    OpenAIRE

    2015-01-01

    The DEEP site sediment sequence obtained during the ICDP SCOPSCO project at Lake Ohrid was dated using tephrostratigraphic information, cyclostratigraphy, and orbital tuning through marine isotope record. Although this approach is suitable for the generation of a general chronological framework of the long succession, it is insufficient to resolve more detailed paleoclimatological questions, such as leads and lags of climate events between marine and terres...

  16. A novel web-based TinT application and the chronology of the Primate Alu retroposon activity

    Directory of Open Access Journals (Sweden)

    Makałowski Wojciech

    2010-12-01

    Full Text Available Abstract Background DNA sequences afford access to the evolutionary pathways of life. Particularly mobile elements that constantly co-evolve in genomes encrypt recent and ancient information of their host's history. In mammals there is an extraordinarily abundant activity of mobile elements that occurs in a dynamic succession of active families, subfamilies, types, and subtypes of retroposed elements. The high frequency of retroposons in mammals implies that, by chance, such elements also insert into each other. While inactive elements are no longer able to retropose, active elements retropose by chance into other active and inactive elements. Thousands of such directional, element-in-element insertions are found in present-day genomes. To help analyze these events, we developed a computational algorithm (Transpositions in Transpositions, or TinT that examines the different frequencies of nested transpositions and reconstructs the chronological order of retroposon activities. Results By examining the different frequencies of such nested transpositions, the TinT application reconstructs the chronological order of retroposon activities. We use such activity patterns as a comparative tool to (1 delineate the historical rise and fall of retroposons and their relations to each other, (2 understand the retroposon-induced complexity of recent genomes, and (3 find selective informative homoplasy-free markers of phylogeny. The efficiency of the new application is demonstrated by applying it to dimeric Alu Short INterspersed Elements (SINE to derive a complete chronology of such elements in primates. Conclusion The user-friendly, web-based TinT interface presented here affords an easy, automated screening for nested transpositions from genome assemblies or trace data, assembles them in a frequency-matrix, and schematically displays their chronological activity history.

  17. Astronautics and aeronautics, 1973: Chronology of science, technology and policy. [including artificial satellites, space probes, and manned space flights

    Science.gov (United States)

    1975-01-01

    A brief chronological account is presented of key events of the year in aerospace sciences. Dates, actions, hardware, persons, scientific discoveries are recorded along with plans, decisions, achievements and preliminary evaluations of results. Samples of public reaction and social impact are included. Sources are identified and an index is provided to aid in tracing related events through the year. The index also serves as a glossary of acronyms and abbreviations.

  18. At neutral pH the chronological lifespan of Hansenula polymorpha increases upon enhancing the carbon source concentrations

    OpenAIRE

    Adam Kawałek; van der Klei, Ida J

    2014-01-01

    Dietary restriction is generally assumed to increase the lifespan in most eukaryotes, including the simple model organism Saccharomyces cerevisiae. However, recent data questioned whether this phenomenon is indeed true for yeast. We studied the effect of reduction of the carbon source concentration on the chronological lifespan of the yeast Hansenula polymorpha using four different carbon sources. Our data indicate that reduction of the carbon source concentration has a negative (glucose, eth...

  19. A new chronology for the Dacian Basin (Romania) : Consequences for the kinematic and paleoenvironmental evolution of the Paratethys region

    OpenAIRE

    Vasiliev, I.

    2006-01-01

    This PhD thesis presents new chronostratigraphic results from the Dacian Basin and adjacent regions as part of the Paratethys paleoprovince. In the first three chapters, a new chronology for the Upper Miocene to Pliocene deposits (approximately 8 to 3 Ma) of the Dacian Basin is presented based on high resolution magneto-biostratigraphic data from the Romanian Carpathians foredeep. The new age control permits the calculation of accumulation rates for each polarity zone, which shows a significa...

  20. Chronological versus dental age in subjects from 5 to 19 years: a comparative study with forensic implications

    Directory of Open Access Journals (Sweden)

    Claudia Corral

    2010-10-01

    Full Text Available Objectives: This study evaluated six methods used in estimating the age of patients attending the Dental School at Universidad del Valle, evaluating dental development by using panoramic radiographs. Additionally, the study determined the sexual identity of the person and the bilateral symmetry of development, the maturity and the chronological eruption of permanent teeth. Materials and methods: This is a descriptive, quantitative and transversal study that evaluated which of the six methods (Logan & Kronfeld; Schour & Massler; Moorrees, Fanning & Hunt; Demirjian, Goldstein & Tanner; Ubelaker & Smith for estimating the age of a patient through radiographic evaluation of dental development is the most correlated with the chronological age of the patient, so it can be used for forensic purposes. Results: The Moorrees, Fanning & Hunt and the Smith methods showed high correlation (0.7874 and 0.7808, respectively. The Logan & Kronfeld methods presented low correlation (0.6879. The sample studied did not show sexual dimorphism or bilateral asymmetry. Conclusions: All methods evaluated have a high correlation coefficient between the dental age and the radiographic age. However, the Moorrees, Fanning & Hunt, and Smith methods presented higher correlation coefficients between dental and chronological age.

  1. Chronological versus dental age in subjects from 5 to 19 years: a comparative study with forensic implications

    Directory of Open Access Journals (Sweden)

    Freddy Moreno

    2010-09-01

    Full Text Available Objectives: This study evaluated six methods used in estimating the age of patients attending the Dental School at Universidad del Valle, evaluating dental development by using panoramic radiographs. Additionally, the study determined the sexual identity of the person and the bilateral symmetry of development, the maturity and the chronological eruption of permanent teeth.Materials and methods: This is a descriptive, quantitative and transversal study that evaluated which of the six methods (Logan & Kronfeld; Schour & Massler; Moorrees, Fanning & Hunt; Demirjian, Goldstein & Tanner; Ubelaker & Smith for estimating the age of a patient through radiographic evaluation of dental development is the most correlated with the chronological age of the patient, so it can be used for forensic purposes.Results: The Moorrees, Fanning & Hunt and the Smith methods showed high correlation (0.7874 and 0.7808, respectively. The Logan & Kronfeld methods presented low correlation (0.6879. The sample studied did not show sexual dimorphism or bilateral asymmetry.Conclusions: All methods evaluated have a high correlation coefficient between the dental age and the radiographic age. However, the Moorrees, Fanning & Hunt, and Smith methods presented higher correlation coefficients between dental and chronological age.

  2. Mandibular third molar development staging to chronologic age and sex in north Indian children and young adults.

    Science.gov (United States)

    Rai, B; Kaur, J; Anand, S C

    2009-12-01

    Age estimation is not only important for clinical but also for medico-legal purposes. The present study is an attempt to estimate the chronologic age based on the stages of third molar development following the eight stages (A-H) method of Demirjian et al8 and to compare third molar development by sex and age. We examined 250 orthopantomograms of young north Indian subjects of known chronologic age (range, 7-26 years). Statistical analysis was performed using the Mann-Whitney U-test and the Wilcoxon test between sex and age. Regression analysis was performed to obtain BR regression formulae for dental age calculation with the chronologic age. Statistically significant differences in mandibular third-molar development between males and females were revealed regarding the calcification stages D and G. The results further indicated that third-molar formation was attained earlier in females than in males. Statistical analysis showed a strong correlation between age and third-molar development for both the sexes.

  3. Atmospheric Mercury Depositional Chronology Reconstructed from Lake Sediments and Ice Core in the Himalayas and Tibetan Plateau.

    Science.gov (United States)

    Kang, Shichang; Huang, Jie; Wang, Feiyue; Zhang, Qianggong; Zhang, Yulan; Li, Chaoliu; Wang, Long; Chen, Pengfei; Sharma, Chhatra Mani; Li, Qing; Sillanpää, Mika; Hou, Juzhi; Xu, Baiqing; Guo, Junming

    2016-03-15

    Alpine lake sediments and glacier ice cores retrieved from high mountain regions can provide long-term records of atmospheric deposition of anthropogenic contaminants such as mercury (Hg). In this study, eight lake sediment cores and one glacier ice core were collected from high elevations across the Himalaya-Tibet region to investigate the chronology of atmospheric Hg deposition. Consistent with modeling results, the sediment core records showed higher Hg accumulation rates in the southern slopes of the Himalayas than those in the northern slopes in the recent decades (post-World War II). Despite much lower Hg accumulation rates obtained from the glacier ice core, the temporal trend in the Hg accumulation rates matched very well with that observed from the sediment cores. The combination of the lake sediments and glacier ice core allowed us to reconstruct the longest, high-resolution atmospheric Hg deposition chronology in High Asia. The chronology showed that the Hg deposition rate was low between the 1500s and early 1800, rising at the onset of the Industrial Revolution, followed by a dramatic increase after World War II. The increasing trend continues to the present-day in most of the records, reflecting the continuous increase in anthropogenic Hg emissions from South Asia. PMID:26878654

  4. Semantic Verbal Fluency in Children with and without Autism Spectrum Disorder: Relationship with Chronological Age and IQ.

    Science.gov (United States)

    Pastor-Cerezuela, Gemma; Fernández-Andrés, Maria-Inmaculada; Feo-Álvarez, Mireia; González-Sala, Francisco

    2016-01-01

    We administered a semantic verbal fluency (SVF) task to two groups of children (age range from 5 to 8): 47 diagnosed with Autism Spectrum Disorder (ASD Group) and 53 with typical development (Comparison Group), matched on gender, chronological age, and non-verbal IQ. Four specific indexes were calculated from the SVF task, reflecting the different underlying cognitive strategies used: clustering (component of generativity and lexical-semantic access), and switching (executive component, cognitive flexibility). First, we compared the performance of the two groups on the different SVF task indicators, with the ASD group scoring lower than the Comparison Group, although the difference was greater on switching than on clustering. Second, we analyzed the relationships between the different SVF measures and chronological age, verbal IQ and non-verbal IQ. While in the Comparison Group chronological age was the main predictor of performance on the SVF task, in the ASD Group verbal IQ was the best predictor. In the children with ASD, therefore, greater linguistic competence would be associated with better performance on the SVF task, which should be taken into account in speech therapies designed to achieve improvements in linguistic generativity and cognitive flexibility. PMID:27379002

  5. “DO NOT BELIEVE IT, DEAR READER”: UPON THE CHRONOLOGY OF THE SHORT STORIES 'VÁRIAS HISTÓRIAS'

    Directory of Open Access Journals (Sweden)

    Saulo Neiva

    2015-12-01

    Full Text Available Additions and corrections of the attributed chronology of the short stories of Várias histórias, proposed by Galante de Sousa (1955, and since then transmitted without changes for several sources.

  6. Chronological Review on Scientific Findings of Bonghan System and Primo Vascular System.

    Science.gov (United States)

    Kang, Kyung A

    2016-01-01

    In 1962, Bonghan Kim in North Korea published a report on a new vascular system in mammals, which he claimed as the acupuncture meridian. He soon named it the Bonghan System. Between 1962 and 1965, he published five reports, with detailed descriptions on the system. Kim also described the self-regenerating nature of a unique cell type Sanals in the system and these cells are now confirmed to be a type of stem cells. According to his findings, the system appears to have vital roles in maintaining mammalian lives. Kim disappeared in around 1965 and the research on this system also completely stopped. In 2002, Kwang-Sup Soh reported re-discovery of the system and, since then, his team has been leading the research on the system. The Soh team has confirmed many of Kim's findings to be valid, although so many of Kim's results are still to be verified. In 2010, the system was renamed the Primo Vascular System (PVS). Soh and researchers trained by Soh have also been reporting new scientific facts on the system. The PVS exists throughout the entire body, including inside the blood and lymphatic vessels. Recent reports revealed more evidence for it to be the acupuncture meridian, where some acupuncture therapies are applied for the blood pressure control. Thus, the PVS is expected to have roles in the oxygen transport in tissues. Many study results also suggest that the PVS may have roles in body homeostasis and regeneration. This article chronologically reviews Kim's scientific findings on the Bonghan System, which were verified by the PVS scientists (after 2000), and also the new findings reported by the PVS scientists. PMID:27526157

  7. Correlated cosmogenic W and Os isotopic variations in Carbo and implications for Hf-W chronology

    Science.gov (United States)

    Qin, Liping; Dauphas, Nicolas; Horan, Mary F.; Leya, Ingo; Carlson, Richard W.

    2015-03-01

    An obstacle for establishing the chronology of iron meteorite formation using 182Hf-182W systematics (t1/2 = 8.9 Myr) is to find proper neutron fluence monitors to correct for cosmic ray modification of W isotopic composition. Recent studies showed that siderophile elements such as Pt and Os could serve such a purpose. To test and calibrate these neutron dosimeters, the isotopic compositions of W and Os were measured in a slab of the IID iron meteorite Carbo. This slab has a well-characterized noble gas depth profile reflecting different degrees of shielding to cosmic rays. The results show that W and Os isotopic ratios correlate with distance from the pre-atmospheric center. Negative correlations, barely resolved within error, were found between ε190Os-ε189Os and ε186Os-ε189Os with slopes of -0.64 ± 0.45 and -1.8(+1.9/-2.1), respectively. These Os isotope correlations broadly agree with model predictions for capture of secondary neutrons produced by cosmic ray irradiation and results reported previously for other groups of iron meteorites. Correlations were also found between ε182W-ε189Os (slope = 1.02 ± 0.37) and ε182W-ε190Os (slope = -1.38 ± 0.58). Intercepts of these two correlations yield pre-exposure ε182W values of -3.32 ± 0.51 and -3.62 ± 0.23, respectively (weighted average ε182W = -3.57 ± 0.21). This value relies on a large extrapolation leading to a large uncertainty but gives a metal-silicate segregation age of -0.5 ± 2.4 Myr after formation of the solar system. Combining the iron meteorite measurements with simulations of cosmogenic effects in iron meteorites, equations are presented to calculate and correct for cosmogenic effects on 182W using Os isotopes.

  8. CHROMIUM ISOTOPE SYSTEMATICS OF ACHONDRITES: CHRONOLOGY AND ISOTOPIC HETEROGENEITY OF THE INNER SOLAR SYSTEM BODIES

    International Nuclear Information System (INIS)

    The standard planetary formation models assume that primitive materials, such as carbonaceous chondrites, are the precursor materials of evolved planetesimals. Past chronological studies have revealed that planetesimals of several hundred kilometers in size, such as the Howardite-Eucrite-Diogenite (HED) parent body (Vesta) and angrite parent body, began their differentiation as early as ∼3 million years of the solar system formation, and continued for at least several million years. However, the timescale of planetesimal formation in distinct regions of the inner solar system, as well as the isotopic characteristics of the reservoirs from which they evolved, remains unclear. Here we present the first report for the precise 53Mn-53Cr ages of monomict ureilites. Chemically separated phases from one monomict ureilite (NWA 766) yielded the Mn-Cr age of 4564.60 ± 0.67 Ma, identical within error to the oldest age preserved in other achondrites, such as angrites and eucrites. The 54Cr isotopic data for this and seven additional bulk ureilites show homogeneous ε54Cr of ∼-0.9, a value distinct from other achondrites and chondrites. Using the ε54Cr signatures of Earth, Mars, and Vesta (HED), we noticed a linear decrease in the ε54Cr value with the heliocentric distance in the inner region of the solar system. If this trend can be extrapolated into the outer asteroid belt, the ε54Cr signatures of monomict ureilites will place the position of the ureilite parent body at ∼2.8 AU. These observations imply that the differentiation of achondrite parent bodies began nearly simultaneously at ∼4565 Ma in different regions of the inner solar system. The distinct ε54Cr value between ureilite and carbonaceous chondrite also implies that a genetic link commonly proposed between the two is unlikely.

  9. Building a 19th Century climate chronology for the Karoo: 1840-1870

    Science.gov (United States)

    Lupini, Athanasia

    2016-04-01

    The need to increase knowledge of global climate change has led to a drive to create long term climatic data sets for countries and smaller regions. With these data sets it is possible to identify patterns in past recent climate and use these to model future climate. The science of historical climatology allows this without having to rely on instrumental data, which may not be available or reliable. Documentary sources usually provide exact dates in which climatic events occur, which can then be utilized to compare to climatic events in neighbouring regions. This study provides the first reconstruction and extended chronology for climate and precipitation for the Albany region in the Eastern Karoo, for 1840-1870, using historical documentary sources. Methodologies were adopted from similar investigations, where any references to the climate were extracted, digitized and categorized according to an index for both rainfall and temperature (Grab and Nash 2010; Nash and Grab, 2010). The data was categorized into an October to September year due to the study site receiving year long rainfall, and final indexes were created for the warm and dry seasons. Droughts that were recorded in this investigation occurred during 1848-1849, 1861-1862, 1862-1863. Floods were identified in 1847-1848, and in 1867-1868. The study site was found to experience significantly drier than wet periods, and the damage described in the accounts from drought was far more severe than that described during periods of flooding. The findings of this study were also compared to several similar studies conducted in neighbouring regions, and a general consistency was found (Grab and Nash 2010; Nash and Grab, 2010; Nash and Endfield, 2002; Vogel, 1989). Further work examining the socio-economic impacts, patterns of locust visitations and comparing modern day to past recent rainfall is also identified.

  10. Understanding the Chronology and Occupation Dynamics of Oversized Pit Houses in the Southern Brazilian Highlands.

    Science.gov (United States)

    Gregorio de Souza, Jonas; Robinson, Mark; Corteletti, Rafael; Cárdenas, Macarena Lucia; Wolf, Sidnei; Iriarte, José; Mayle, Francis; DeBlasis, Paulo

    2016-01-01

    A long held view about the occupation of southern proto-Jê pit house villages of the southern Brazilian highlands is that these sites represent cycles of long-term abandonment and reoccupation. However, this assumption is based on an insufficient number of radiocarbon dates for individual pit houses. To address this problem, we conducted a programme of comprehensive AMS radiocarbon dating and Bayesian modelling at the deeply stratified oversized pit House 1, Baggio I site (Cal. A.D. 1395-1650), Campo Belo do Sul, Santa Catarina state, Brazil. The stratigraphy of House 1 revealed an unparalleled sequence of twelve well preserved floors evidencing a major change in occupation dynamics including five completely burnt collapsed roofs. The results of the radiocarbon dating allowed us to understand for the first time the occupation dynamics of an oversized pit house in the southern Brazilian highlands. The Bayesian model demonstrates that House 1 was occupied for over two centuries with no evidence of major periods of abandonment, calling into question previous models of long-term abandonment. In addition, the House 1 sequence allowed us to tie transformations in ceramic style and lithic technology to an absolute chronology. Finally, we can provide new evidence that the emergence of oversized domestic structures is a relatively recent phenomenon among the southern proto-Jê. As monumental pit houses start to be built, small pit houses continue to be inhabited, evidencing emerging disparities in domestic architecture after AD 1000. Our research shows the importance of programmes of intensive dating of individual structures to understand occupation dynamics and site permanence, and challenges long held assumptions that the southern Brazilian highlands were home to marginal cultures in the context of lowland South America. PMID:27384341

  11. A refined chronology of prehistoric Madagascar and the demise of the megafauna

    Science.gov (United States)

    Crowley, Brooke E.

    2010-09-01

    The vertebrate community of Madagascar is one of the most unique and diverse on Earth, yet faunal diversity today is just a fraction of that present in the Pleistocene and Early Holocene. An understanding of the chronology of extinction relative to climate change and anthropogenic factors is essential to test hypotheses for extinction. Here, I combine over 200 new radiocarbon dates with published 14C dates from extinct and extant subfossil vertebrates. These new data provide evidence for the prolonged existence of both extant and extinct endemic terrestrial vertebrate species well before human arrival, with habitation of some localities extending back before the Last Glacial Maximum. I analyze the data for patterns among body sizes and ecoregions in relation to four major historical events: human arrival (ca 2500 years ago), establishment of human settlements (ca 1500 years ago), Late Holocene aridification (peaking ca 1000 years ago), and European arrival (ca 500 years ago). Patterns in endemic species abundance after human arrival differ depending on body size and geographic location. Within the first 500 years after human arrival, there were population declines in (1) very large species (>150 kg) and large species (10-150 kg) in the Dry Deciduous Forest, (2) large species in the Central Highlands, and (3) very large species in the Spiny Thicket. This first pulse of declines was likely triggered by human predation. Large species continued to be well represented in the Spiny Thicket and Succulent Woodland until ca 1000 years ago, when their populations plummeted. This second pulse of declines may have been solely triggered by continued human predation, or it may have resulted from a combination of increasing Late Holocene aridity and human impacts in the form of hunting and habitat modification. The abundance of endemic animals weighing <10 kg increased dramatically in the aftermath of the decline in large-bodied species.

  12. TEnest: automated chronological annotation and visualization of nested plant transposable elements.

    Science.gov (United States)

    Kronmiller, Brent A; Wise, Roger P

    2008-01-01

    Organisms with a high density of transposable elements (TEs) exhibit nesting, with subsequent repeats found inside previously inserted elements. Nesting splits the sequence structure of TEs and makes annotation of repetitive areas challenging. We present TEnest, a repeat identification and display tool made specifically for highly repetitive genomes. TEnest identifies repetitive sequences and reconstructs separated sections to provide full-length repeats and, for long-terminal repeat (LTR) retrotransposons, calculates age since insertion based on LTR divergence. TEnest provides a chronological insertion display to give an accurate visual representation of TE integration history showing timeline, location, and families of each TE identified, thus creating a framework from which evolutionary comparisons can be made among various regions of the genome. A database of repeats has been developed for maize (Zea mays), rice (Oryza sativa), wheat (Triticum aestivum), and barley (Hordeum vulgare) to illustrate the potential of TEnest software. All currently finished maize bacterial artificial chromosomes totaling 29.3 Mb were analyzed with TEnest to provide a characterization of the repeat insertions. Sixty-seven percent of the maize genome was found to be made up of TEs; of these, 95% are LTR retrotransposons. The rate of solo LTR formation is shown to be dissimilar across retrotransposon families. Phylogenetic analysis of TE families reveals specific events of extreme TE proliferation, which may explain the high quantities of certain TE families found throughout the maize genome. The TEnest software package is available for use on PlantGDB under the tools section (http://www.plantgdb.org/prj/TE_nest/TE_nest.html); the source code is available from (http://wiselab.org).

  13. Topography of the goldfish optic tracts: implications for the chronological clustering model.

    Science.gov (United States)

    Springer, A D; Mednick, A S

    1985-09-01

    Both the dorsal and ventral optic tracts of goldfish have similar shapes when they are sectioned perpendicularly to their longitudinal axes. Each tract is pear-shaped, consisting of a narrow and a deep apex, a wide midspan, and a progressively curved and tapered superficial base. The tracts differ in that the apex of the dorsal optic tract points caudally, while the apex of the ventral optic tract points medially. In addition, upon segregating from the main optic tract, the dorsal optic tract courses dorsally while the ventral optic tract courses caudally. Thus, the two optic tracts have similar shapes and are orthongonal to one another. The topography of the retinal fibers within the optic tracts was determined either by ablating part of the retina and subsequently filling the axons from the intact hemiretina with cobaltous-lysine or by applying cobaltous-lysine to a slit in the retina. Both optic tracts contain a similar arrangement of optic fibers. Axons of central retinal ganglion cells (RGCs) are in the apex of each tract and optic fibers of peripheral RGCs are located along the base of each tract. Axons of temporal RGCs are located dorsally in the ventral optic tract and laterally in the dorsal optic tract, while axons of nasal RGCs are located ventrally in the ventral optic tract and medially in the dorsal optic tract. These findings indicate that the optic axons are organized as laminae. Deeper laminae contain the axons of older annuli of RGCs and superficial laminae contain the axons of younger annuli of RGCs. This type of chronological organization appears to be consistent across vertebrates.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:4044928

  14. Assessment of Chronological Effects of Irreversible Electroporation on Hilar Bile Ducts in a Porcine Model

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jae Woong, E-mail: cooljay@korea.ac.kr; Lu, David S. K., E-mail: dlu@mednet.ucla.edu; Osuagwu, Ferdnand, E-mail: fosuagwu@mednet.ucla.edu; Raman, Steven, E-mail: sraman@mednet.ucla.edu [David Geffen School of Medicine at UCLA, Department of Radiology (United States); Lassman, Charles, E-mail: classman@mednet.ucla.edu [David Geffen School of Medicine at UCLA, Department of Pathology (United States)

    2013-11-07

    PurposeTo evaluate the chronological effects of irreversible electroporation (IRE) on large hilar bile ducts in an in vivo porcine model correlated with computed tomography (CT) cholangiography and histopathology.Materials and MethodsTwelve IRE zones were made along hilar bile ducts intraoperatively under ultrasound (US)-guidance in 11 pigs. Paired electrodes were placed either on opposing sides of the bile duct (straddle [STR]) or both on one side of the bile duct (one-sided [OSD]). The shortest electrode-to-duct distance was classified as periductal (≤2 mm) or nonperiductal (>2 mm). CT cholangiography and laboratory tests were performed before IRE and again at 2 days, 4 weeks, and 8 weeks after IRE. Degree of bile duct injury were graded as follows: grade 0 = no narrowing; grade 1 = ≤50 % duct narrowing; grade 2 = >50 % narrowing without proximal duct dilatation; grade 3 = grade 2 with proximal duct dilatation; and grade 4 = grade 3 with enzyme elevation. Pigs were selected for killing and histopathology at 2 days, 4, and 8 weeks.ResultsNonperiductal electrode placement produced no long-term strictures in 5 of 5 ducts. Periductal electrode placement produced mild narrowing in 6 of 7 ducts: 5 grade 1 and 1 grade 2. None showed increased enzymes. There was no significant difference between STR versus OSD electrode placement. Histopathology showed minor but relatively greater ductal mural changes in narrowed ducts.ConclusionIn the larger hilar ducts, long-term patency and mural integrity appear resistant to IRE damage with the energy deposition used, especially if the electrode is not immediately periductal in position.

  15. Chronology, Eruption Duration, and Atmospheric Contribution of the Martian Volcano Apollinaris Patera

    Science.gov (United States)

    Robinson, M.S.; Mouginis-Mark, P. J.; Zimbelman, J.R.; Wu, S.S.C.; Ablin, K.K.; Howington-Kraus, A. E.

    1993-01-01

    Geologic mapping, thermal inertia measurements, and an analysis of the color (visual wavelengths) of the martian volcano Apollinaris Patera indicate the existence of two different surface materials, comprising an early, easily eroded edifice, and a more recent, competent fan on the southern flank. A chronology of six major events that is consistent with the present morphology of the volcano has been identified. We propose that large scale explosive activity occurred during the formation of the main edifice and that the distinctive fan on the southern flank appears to have been formed by lavas of low eruptive rate similar to those that form compound pahoehoe flow fields on Earth. A basal escarpment typically 500 m in relief and morphologically similar to the one surrounding Olympus Mons was produced between the formation of the main edifice and the fan, indicating multistage eruptions over a protracted period of time. Contact relations between the volcanic units and the adjacent chaotic material indicate that formation of the chaotic material occurred over an extended period of time and may be related to the volcanic activity that formed Apollinaris Patera. Stereophotogrammetric measurements permit the volume of the volcano to be estimated at 105 km3. From this volume measurement and an inferred eruption rate (1.5 ?? 10-2 km3 yr-1) we estimate the total eruption duration for the main edifice to be ???107 yrs. Plausible estimates of the exsolved volatile content of the parent magma imply that greater than 1015 kg of water vapor was released into the atmosphere as a consequence of this activity. This large amount of water vapor as well as other exsolved gases must have had a significant impact on local, and possibly global, climatic conditions. ?? 1993 Academic Press. All rights reserved.

  16. A high-resolution chronology of rapid forest transitions following polynesian arrival in New Zealand.

    Directory of Open Access Journals (Sweden)

    David B McWethy

    Full Text Available Human-caused forest transitions are documented worldwide, especially during periods when land use by dense agriculturally-based populations intensified. However, the rate at which prehistoric human activities led to permanent deforestation is poorly resolved. In the South Island, New Zealand, the arrival of Polynesians c. 750 years ago resulted in dramatic forest loss and conversion of nearly half of native forests to open vegetation. This transformation, termed the Initial Burning Period, is documented in pollen and charcoal records, but its speed has been poorly constrained. High-resolution chronologies developed with a series of AMS radiocarbon dates from two lake sediment cores suggest the shift from forest to shrubland occurred within decades rather than centuries at drier sites. We examine two sites representing extreme examples of the magnitude of human impacts: a drier site that was inherently more vulnerable to human-set fires and a wetter, less burnable site. The astonishing rate of deforestation at the hands of small transient populations resulted from the intrinsic vulnerability of the native flora to fire and from positive feedbacks in post-fire vegetation recovery that increased landscape flammability. Spatially targeting burning in highly-flammable seral vegetation in forests rarely experiencing fire was sufficient to create an alternate fire-prone stable state. The New Zealand example illustrates how seemingly stable forest ecosystems can experience rapid and permanent conversions. Forest loss in New Zealand is among the fastest ecological transitions documented in the Holocene; yet equally rapid transitions can be expected in present-day regions wherever positive feedbacks support alternate fire-inhibiting, fire-prone stable states.

  17. Ice Core Depth-Age Relation for Vostok delta-D and Dome Fuji delta-18O Records Based on the Devils Hole Paleotemperature Chronology

    Science.gov (United States)

    Landwehr, Jurate Maciunas

    2002-01-01

    This report presents the data for the Vostok - Devils Hole chronology, termed V-DH chronology, for the Antarctic Vostok ice core record. This depth - age relation is based on a join between the Vostok deuterium profile (D) and the stable oxygen isotope ratio (18O) record of paleotemperature from a calcitic core at Devils Hole, Nevada, using the algorithm developed by Landwehr and Winograd (2001). Both the control points defining the V-DH chronology and the numeric values for the chronology are given. In addition, a plausible chronology for a deformed bottom portion of the Vostok core developed with this algorithm is presented. Landwehr and Winograd (2001) demonstrated the broader utility of their algorithm by applying it to another appropriate Antarctic paleotemperature record, the Antarctic Dome Fuji ice core 18O record. Control points for this chronology are also presented in this report but deemed preliminary because, to date, investigators have published only the visual trace and not the numeric values for the Dome Fuji 18O record. The total uncertainty that can be associated with the assigned ages is also given.

  18. The eruptive chronology of the Ampato-Sabancaya volcanic complex (Southern Peru)

    Science.gov (United States)

    Samaniego, Pablo; Rivera, Marco; Mariño, Jersy; Guillou, Hervé; Liorzou, Céline; Zerathe, Swann; Delgado, Rosmery; Valderrama, Patricio; Scao, Vincent

    2016-09-01

    We have reconstructed the eruptive chronology of the Ampato-Sabancaya volcanic complex (Southern Peru) on the basis of extensive fieldwork, and a large dataset of geochronological (40K-40Ar, 14C and 3He) and geochemical (major and trace element) data. This volcanic complex is composed of two successive edifices that have experienced discontinuous volcanic activity from Middle Pleistocene to Holocene times. The Ampato compound volcano consists of a basal edifice constructed over at least two cone-building stages dated at 450-400 ka and 230-200 ka. After a period of quiescence, the Ampato Upper edifice was constructed firstly during an effusive stage (80-70 ka), and then by the formation of three successive peaks: the Northern, Southern (40-20 ka) and Central cones (20-10 ka). The Southern peak, which is the biggest, experienced large explosive phases, resulting in deposits such as the Corinta plinian fallout. During the Holocene, eruptive activity migrated to the NE and constructed the mostly effusive Sabancaya edifice. This cone comprised many andesitic and dacitic blocky lava flows and a young terminal cone, mostly composed of pyroclastic material. Most samples from the Ampato-Sabancaya define a broad high-K magmatic trend composed of andesites and dacites with a mineral assemblage of plagioclase, amphibole, biotite, ortho- and clino-pyroxene, and Fe-Ti oxides. A secondary trend also exists, corresponding to rare dacitic explosive eruptions (i.e. Corinta fallout and flow deposits). Both magmatic trends are derived by fractional crystallisation involving an amphibole-rich cumulate with variable amounts of upper crustal assimilation. A marked change in the overall eruptive rate has been identified between Ampato (~ 0.1 km3/ka) and Sabancaya (0.6-1.7 km3/ka). This abrupt change demonstrates that eruptive rates have not been homogeneous throughout the volcano's history. Based on tephrochronologic studies, the Late Holocene Sabancaya activity is characterised by strong

  19. Multi-method chronological investigation of a Middle Paleolithic stratigraphic context in Eastern Transylvania, Romania

    Science.gov (United States)

    Veres, Daniel; Cosac, Marian; Muratoreanu, George; Niţǎ, Loredana; Schmidt, Christoph; Hambach, Ulrich; Hubay, Katalin; Alexandru, Radu; Cuculici, Roxana; Lucian Buzea, Dan; Dumitraşcu, Valentin

    2016-04-01

    The Middle to Upper Paleolithic transition is one of the crucial periods of change in the prehistory of Europe due to the full emergence, continent-wide, of modern human technologies, detrimental of Neanderthal survival. Knowledge about the transition is vast, however, the evidence for cultural and technological developments in the Carpathian - Lower Danube area is still rather sparse. Here we discuss latest results arising from an archaeological-chronological investigation of a Middle Paleolithic context within the Varghis karst, eastern Transylvania, Romania. Combining our results with these of previous excavations, we can distinguish several stages of habitation in the area comprising a rock shelter connected to a newly discovered filled-in cave entrance. Reanalysis of the deeper stratigraphy previously unexcavated shows that at least two main habitation levels have been preserved. In both levels, the bone assemblages (Bos/Bison, Capra, Canis lupus, Ursus spaeleus) directly associated with lithics point to human-accumulation of material. In order to augment the typological cultural considerations, we applied direct radiocarbon dating on bones from within the occupation layers and on scattered charcoal, for the latter following a two-step combustion protocol (1). Radiocarbon dating on bones suggests the lowermost occupation layer is >43.4 radiocarbon kyr BP old, whereas the preliminary infrared stimulated luminescence (IRSL) ages on the lowermost productive layer and above it indicate surprisingly old ages of ca. 120 kyr and respectively, ca. 70 kyr. Multiple-protocol dating of charcoal found within the two habitation layers produced ages >38 radiocarbon kyr BP, suggesting that the lowermost habitation layer unequivocally pertains to the Middle Paleolithic industries. For the upper productive layer, radiocarbon dating of charcoal found 20 cm above it produced a surprisingly young age of 17.4 radiocarbon kyr BP. However, as the carbon content of this sample was

  20. Chronological refinement of an ice core record at Upper Fremont Glacier in south central North America

    International Nuclear Information System (INIS)

    The potential to use ice cores from alpine glaciers in the midlatitudes to reconstruct paleoclimatic records has not been widely recognized. Although excellent paleoclimatic records exist for the polar regions, paleoclimatic ice core records are not common from midlatitude locations. An ice core removed from the Upper Fremont Glacier in Wyoming provides evidence for abrupt climate change during the mid-1800s. Volcanic events (Krakatau and Tambora) identified from electrical conductivity measurements (ECM) and isotopic and chemical data from the Upper Fremont Glacier were reexamined to confirm and refine previous chronological estimates of the ice core. At a depth of 152 m the refined age-depth profile shows good agreement (1736±10 A.D.) with the 14C age date (1729±95 A.D.). The δ18O profile of the Upper Fremont Glacier (UFG) ice core indicates a change in climate known as the Little Ice Age (LIA). However, the sampling interval for δ18O is sufficiently large (20 cm) such that it is difficult to pinpoint the LIA termination on the basis of δ18O data alone. Other research has shown that changes in the δ18O variance are generally coincident with changes in ECM variance. The ECM data set contains over 125,000 data points at a resolution of 1 data point per millimeter of ice core. A 999-point running average of the ECM data set and results from f tests indicates that the variance of the ECM data decreases significantly at about 108 m. At this depth, the age-depth profile predicts an age of 1845 A.D. Results indicate the termination of the LIA was abrupt with a major climatic shift to warmer temperatures around 1845 A.D. and continuing to present day. Prediction limits (error bars) calculated for the profile ages are ±10 years (90% confidence level). Thus a conservative estimate for the time taken to complete the LIA climatic shift to present-day climate is about 10 years, suggesting the LIA termination in alpine regions of central North America may have occurred

  1. Synchronizing the North American Varve Chronology with Greenland ice core records using meteoric 10Be flux

    Science.gov (United States)

    DeJong, B.; Balco, G.; Ridge, J. C.; Rood, D. H.; Bierman, P. R.

    2012-12-01

    The North American Varve Chronology (NAVC) is a floating 5700-year sequence of glacial lake varves deposited in the Connecticut River Valley of the northeast US ~18,000-12,500 years ago. The NAVC is an annually resolved record of regional climate and ice-marginal processes at 40-45° N latitude, near the margin of the retreating Laurentide Ice Sheet (LIS). NAVC deposition occurred at the same time as rapid and abrupt Arctic and North Atlantic climate changes that took place during the last deglaciation. An age estimate for the NAVC based on radiocarbon dated plant macrofossils in individual varves implies a relationship between ice-marginal events recorded by the NAVC and climate events recorded in Greenland ice cores. For example, the retreat rate of the LIS up the Connecticut River Valley increased during the Bolling warming in Greenland, a readvance of the LIS margin took place during the Older Dryas cold period, and a correlation between an outburst flood from glacial Lake Iroquois and the Intra-Allerod Cold Period supports the hypothesis that the flood affected North Atlantic thermohaline circulation. On the other hand, a doubling of the ice-margin retreat rate recorded by the NAVC around 16,000 years ago coincides with a relatively cold period in Greenland. Our goal is to investigate the precise time relationship between these events by synchronizing the NAVC with the Greenland ice core time scale using atmospherically-produced 10Be. Existing 10Be flux records, including those from Greenland ice cores, exhibit solar variability on a range of time scales. Because this variability is globally synchronous, a 10Be flux record for the NAVC can, in principle, be used to align NAVC and ice core timescales. We are generating such a record at present. First, we are analyzing short varve sections at high temporal resolution to evaluate the magnitude of solar variability signals; a single section analyzed so far displays interannual variability with a period consistent

  2. Correlations between radiometric analysis of Quaternary deposits and the chronology of prehistoric settlements from the southeastern Brazilian coast

    Energy Technology Data Exchange (ETDEWEB)

    Anjos, R.M., E-mail: meigikos@if.uff.b [Instituto de Fisica, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, s/no, Gragoata, 24210-346 Niteroi, RJ (Brazil); Macario, K.D. [Instituto de Fisica, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, s/no, Gragoata, 24210-346 Niteroi, RJ (Brazil); Lima, T.A. [Departamento de Antropologia, Museu Nacional, Universidade Federal do Rio de Janeiro, Quinta da Boa Vista, s/no, Sao Cristovao, 20940-040 Rio de Janeiro, RJ (Brazil); Veiga, R.; Carvalho, C.; Fernandes, P.J.F.; Vezzone, M.; Bastos, J. [Instituto de Fisica, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, s/no, Gragoata, 24210-346 Niteroi, RJ (Brazil)

    2010-01-15

    Natural gamma radiation measurements of sand deposits were carried out in order to study the chronology of prehistoric colonization of the Brazilian coast during the Holocene. The method employs thorium, uranium and potassium as tracers of the geological provenance of Quaternary deposits, where artificial shellmounds are found. The so-called sambaquis are archaeological settlements, characteristic of fisher-gatherers, specialized in the exploitation of shellfish. Our results show a considerable positive correlation between the formation of coastal deposits, based on cross plots of eTh/eU and eTh/K, and the antiquity of its prehistoric human occupation.

  3. Architecture, cobbled roads and chronology of the main sector of the site Las Mercedes-1, Central Caribbean of Costa Rica

    International Nuclear Information System (INIS)

    Results from test-pit excavations, survey, and mapping at Las Mercedes-1, plus the center of a paramount chiefly polity in the Central Caribbean region of Costa Rica, are presented. Information on architecture, construction system, ceramic chronology, and funerary features, are reported. Radiocarbon dates have suggested that important construction works at the site's center were carried out circa A.D. 1000. Two cobble-paved, causeways, perpendicular to the river drainage system, were found to be linked to the main monumental compound as roads for formal access. Interest in the site has been revived and points the way to further researches at the site and its regional sphere. (author)

  4. IceChrono1: a probabilistic model to compute a common and optimal chronology for several ice cores

    Science.gov (United States)

    Parrenin, Frédéric; Bazin, Lucie; Capron, Emilie; Landais, Amaëlle; Lemieux-Dudon, Bénédicte; Masson-Delmotte, Valérie

    2016-04-01

    Polar ice cores provide exceptional archives of past environmental conditions. The dating of ice cores and the estimation of the age scale uncertainty are essential to interpret the climate and environmental records that they contain. It is however a complex problem which involves different methods. Here, we present IceChrono1, a new probabilistic model integrating various sources of chronological information to produce a common and optimized chronology for several ice cores, as well as its uncertainty. IceChrono1 is based on the inversion of three quantities: the surface accumulation rate, the Lock-In Depth (LID) of air bubbles and the thinning function. The chronological information integrated into the model are: models of the sedimentation process (accumulation of snow, densification of snow into ice and air trapping, ice flow), ice and air dated horizons, ice and air depth intervals with known durations, Δdepth observations (depth shift between synchronous events recorded in the ice and in the air) and finally air and ice stratigraphic links in between ice cores. The optimization is formulated as a least squares problem, implying that all densities of probabilities are assumed to be Gaussian. It is numerically solved using the Levenberg-Marquardt algorithm and a numerical evaluation of the model's Jacobian. IceChrono follows an approach similar to that of the Datice model which was recently used to produce the AICC2012 chronology for 4 Antarctic ice cores and 1 Greenland ice core. IceChrono1 provides improvements and simplifications with respect to Datice from the mathematical, numerical and programming point of views. The capabilities of IceChrono is demonstrated on a case study similar to the AICC2012 dating experiment. We find results similar to those of Datice, within a few centuries, which is a confirmation of both IceChrono and Datice codes. We also test new functionalities with respect to the original version of Datice: observations as ice intervals

  5. Dry seasons identified in oak tree-ring chronology in the Czech Lands over the last millennium

    Science.gov (United States)

    Dobrovolny, Petr; Brazdil, Rudolf; Büntgen, Ulf; Rybnicek, Michal; Kolar, Tomas; Reznickova, Ladislava; Valasek, Hubert; Kotyza, Oldrich

    2015-04-01

    There is growing evidence on amplification of hydrological regimes as a consequence of rising temperatures, increase in evaporation and changes in circulation patterns. These processes may be responsible for higher probability of hydroclimatic extremes occurrence in regional scale. Extreme events such as floods or droughts are rare from their definition and for better understanding of possible changes in the frequency and intensity of their occurrence, long-term proxy archives may be analysed. Recently several tree ring width chronologies were compiled from hardwood species occurring in lowland positions and their analysis proved that they are moisture-sensitive and suitable for hydroclimate reconstructions. Here, we introduce a new oak (Quercus sp) ring width (RW) dataset for the Czech Republic and the last 1250 years. We explain the process of oak chronology standardization that was based on several only slightly different de-trending techniques and subsequent chronology development steps. We hypothesize that the most severe RW increment reductions (negative extremes) reflect extremely dry spring-summer conditions. Negative extremes were assigned for years in which transformed oak RWs were lower than the minus 1.5 standard deviation. To verify our hypothesis, we compare typical climatic conditions in negative extreme years with climatology of the reference period 1961-1990. Comparison was done for various instrumental measurements (1805-2012), existing proxy reconstructions (1500-1804) and also for documentary evidence from historical archives (before 1500). We found that years of negative extremes are characterized with distinctly above average spring (MAM) and summer (JJA) air temperatures and below average precipitation amounts. Typical sea level pressure spatial distribution in those years shows positive pressure anomaly over British Isles and Northern Sea, the pattern that synoptically corresponds to blocking anticyclone bringing to Central Europe warm air

  6. Re-evaluation of the age model for North Atlantic Ocean Site 982 – arguments for a return to the original chronology

    Directory of Open Access Journals (Sweden)

    K. T. Lawrence

    2013-04-01

    Full Text Available Recently, the veracity of the published chronology for the Pliocene section of North Atlantic Ocean Drilling Program Site 982 was called into question. Here, we examine the robustness of the original age model as well as the proposed age model revision. The proposed revision is predicated on an apparent mis-identification of the depth to the Gauss-Matuyama (G/M polarity chronozone reversal boundary (2.581 Ma based on preliminary shipboard paleomagnetic data and offers a new chronology which includes a hiatus between ~ 3.2 and 3 Ma. However, an even more accurate shore-based, u-channel-derived polarity chronozone stratigraphy for the past ~ 2.7 Ma supports the shipboard composite stratigraphy and demonstrates that the original estimate of the depth of the G/M reversal in the Site 982 record is correct. Thus, the main justification forwarded to support the revised chronology is not valid. We demonstrate that the proposed revision results in a pronounced anomaly in sedimentation rates proximal to the proposed hiatus, erroneous assignment of marine-isotope stages in the Site 982 Pliocene benthic stable oxygen isotope stratigraphy, and a markedly worse correlation of proxy records between this site and other regional paleoclimate data. We conclude that the original chronology for Site 982 is a far more accurate age-model than that which arises from the published revision. We strongly recommend the use of the original chronology for all future work at Site 982.

  7. Re-evaluation of the age model for North Atlantic Ocean Site 982 – arguments for a return to the original chronology

    Directory of Open Access Journals (Sweden)

    K. T. Lawrence

    2013-10-01

    Full Text Available Recently, the veracity of the published chronology for the Pliocene section of North Atlantic Ocean Drilling Program Site 982 was called into question. Here, we examine the robustness of the original age model as well as the proposed age model revision. The proposed revision is predicated on an apparent misidentification of the depth to the Gauss–Matuyama (G/M polarity chronozone reversal boundary (2.581 Ma based on preliminary shipboard paleomagnetic data, and offers a new chronology that includes a hiatus between ~3.2 and 3 Ma. However, an even more accurate shore-based, u-channel-derived polarity chronozone stratigraphy for the past ~2.7 Ma supports the shipboard composite stratigraphy and demonstrates that the original estimate of the depth of the G/M reversal in the Site 982 record is correct. Thus, the main justification forwarded to support the revised chronology no longer exists. We demonstrate that the proposed revision results in a pronounced anomaly in sedimentation rates proximal to the proposed hiatus, erroneous assignment of marine-isotope stages in the Site 982 Pliocene benthic stable oxygen isotope stratigraphy, and a markedly worse correlation of proxy records between this site and other regional paleoclimate data. We conclude that the original chronology for Site 982 is a far more accurate age model than that which arises from the published revision. We strongly recommend the use of the original chronology for all future work at Site 982.

  8. A 10Be Chronology of Late Pleistocene and Holocene Glaciation in the Rwenzori Mountains, Uganda

    Science.gov (United States)

    Baber, M.; Kelly, M. A.; Russell, J. M.; Loomis, S. E.

    2012-12-01

    Although the retreat of glaciers in East Africa has been monitored over the last century, longer-term records of African glacier fluctuations are scarce. The Rwenzori Mountains, located on the border of Uganda and the Democratic Republic of Congo, host the largest glacial system in Africa and provide an opportunity for extensive investigation of past glaciations. We mapped and applied surface exposure (10Be) dating to glacial moraines deposited since the end of the last ice age in the Rwenzori Mountains to test the feasibility of 10Be dating at this site and to develop a chronology of glacial fluctuations. Our study is the first to use 10Be dating of glacial features in Africa and is possible because the Rwenzori host quartz-rich lithologies. By comparing the timing of Rwenzori glacial advances with other paleoclimate records from East Africa, we also will examine the climatic conditions which influenced tropical glacier fluctuations. Osmaston (1989) mapped moraines in the Rwenzori Mountains, documenting three stages of Pleistocene and Holocene glaciations, the Mahoma, Omurubaho and Lac Gris stages. The Mahoma stage moraines are estimated to be older than 17,980 ± 780 yr BP (D. M. Livingstone, 1962) by basal 14C dating of sediments from Lake Mahoma, situated in large lateral moraine at 2990 m asl. The age of the Omurubaho stage moraine is estimated from a basal 14C age (7,730 ± 150 yr BP) Lower Kitandara Lake (3990 m asl) and dammed by an Omurubaho stage moraine. The Lac Gris moraines are estimated at ~150-700 yr BP (de Heinzelin, 1953; Bergström, 1955) based on rates of lichen growth and plant colonization on moraines about 200 m below current glacial positions on Mt. Stanley. Though considerable uncertainty remains for the ages of these glacier deposits, these three stages most likely represent ages from the LGM to the LIA. We present two new 10Be ages of boulders from two moraines in the Nyamagusani Valley, ~4000 m asl. Sample KOP-2 (4033 m asl) is from the

  9. Rewiring yeast acetate metabolism through MPC1 loss of function leads to mitochondrial damage and decreases chronological lifespan

    Directory of Open Access Journals (Sweden)

    Ivan Orlandi

    2014-11-01

    Full Text Available During growth on fermentable substrates, such as glucose, pyruvate, which is the end-product of glycolysis, can be used to generate acetyl-CoA in the cytosol via acetaldehyde and acetate, or in mitochondria by direct oxidative decarboxylation. In the latter case, the mitochondrial pyruvate carrier (MPC is responsible for pyruvate transport into mitochondrial matrix space. During chronological aging, yeast cells which lack the major structural subunit Mpc1 display a reduced lifespan accompanied by an age-dependent loss of autophagy. Here, we show that the impairment of pyruvate import into mitochondria linked to Mpc1 loss is compensated by a flux redirection of TCA cycle intermediates through the malic enzyme-dependent alternative route. In such a way, the TCA cycle operates in a “branched” fashion to generate pyruvate and is depleted of intermediates. Mutant cells cope with this depletion by increasing the activity of glyoxylate cycle and of the pathway which provides the nucleocytosolic acetyl-CoA. Moreover, cellular respiration decreases and ROS accumulate in the mitochondria which, in turn, undergo severe damage. These acquired traits in concert with the reduced autophagy restrict cell survival of the mpc1∆ mutant during chronological aging. Conversely, the activation of the carnitine shuttle by supplying acetyl-CoA to the mitochondria is sufficient to abrogate the short-lived phenotype of the mutant.

  10. Aligning MIS5 proxy records from Lake Ohrid (FYROM with independently dated Mediterranean archives: implications for core chronology

    Directory of Open Access Journals (Sweden)

    G. Zanchetta

    2015-10-01

    Full Text Available The DEEP site sediment sequence obtained during the ICDP SCOPSCO project at Lake Ohrid was dated using tephrostratigraphic information, cyclostratigraphy, and orbital tuning through marine isotope record. Although this approach is suitable for the generation of a general chronological framework of the long succession, it is insufficient to resolve more detailed paleoclimatological questions, such as leads and lags of climate events between marine and terrestrial records or between different regions. In this paper, we demonstrate how the use of different tie points can affect cyclostratigraphy and orbital tuning for the period between ca. 140 and 70 ka and how the results can be correlated with directly/indirectly radiometrically-dated Mediterranean marine and continental proxy records. The alternative age model obtained shows consistent differences with that proposed by Francke et al. (2015 for the same interval, in particular at the level of the MIS6-5e transition. According to this age model, different proxies from the DEEP site sediment record support an increase of temperatures between glacial to interglacial conditions, which is almost synchronous with a rapid increase in sea surface temperature observed in the western Mediterranean. The results show how important a detailed study of independent chronological tie points is for synchronizing different records and to highlight asynchronisms of climate events.

  11. The reliability of chronological age determination by means of mandibular third molar development in subjects in Croatia.

    Science.gov (United States)

    Legović, Mario; Sasso, Anja; Legović, Izak; Brumini, Gordana; Cabov, Tomislav; Slaj, Martina; Vancura, Irena; Lapter, Marina

    2010-01-01

    The aim of this study was to determine the development of the mandibular third molar and its relation to chronological age. The evaluated material consisted of 979 orthopantomograms of patients of Croatian Caucasian origin aged between 5.7 and 14.6 years. Third molar developmental stages were evaluated according to the stages proposed by Nolla. The frequencies of different stages of mineralization and the mean value of the mineralization of the mandibular third molars with regard to age, gender, and size of the mandible were determined and the coefficient of correlation determined between the age of the subject and the stage of development of the mandibular molars. Statistically significant correlation was determined between mineralization of the mandibular third molar and chronological age of the subjects (boys, mandibular left third molar r = 0.779, right third molar r = 0.793; girls, mandibular left third molar r = 0.746, right third molar r = 0.725). It can be concluded that the accuracy of age estimation based on Nolla's method is applicable for Croatian children.

  12. Aligning MIS5 proxy records from Lake Ohrid (FYROM) with independently dated Mediterranean archives: implications for core chronology

    Science.gov (United States)

    Zanchetta, G.; Regattieri, E.; Giaccio, B.; Wagner, B.; Sulpizio, R.; Francke, A.; Vogel, L. H.; Sadori, L.; Masi, A.; Sinopoli, G.; Lacey, J. H.; Leng, M. L.; Leicher, N.

    2015-10-01

    The DEEP site sediment sequence obtained during the ICDP SCOPSCO project at Lake Ohrid was dated using tephrostratigraphic information, cyclostratigraphy, and orbital tuning through marine isotope record. Although this approach is suitable for the generation of a general chronological framework of the long succession, it is insufficient to resolve more detailed paleoclimatological questions, such as leads and lags of climate events between marine and terrestrial records or between different regions. In this paper, we demonstrate how the use of different tie points can affect cyclostratigraphy and orbital tuning for the period between ca. 140 and 70 ka and how the results can be correlated with directly/indirectly radiometrically-dated Mediterranean marine and continental proxy records. The alternative age model obtained shows consistent differences with that proposed by Francke et al. (2015) for the same interval, in particular at the level of the MIS6-5e transition. According to this age model, different proxies from the DEEP site sediment record support an increase of temperatures between glacial to interglacial conditions, which is almost synchronous with a rapid increase in sea surface temperature observed in the western Mediterranean. The results show how important a detailed study of independent chronological tie points is for synchronizing different records and to highlight asynchronisms of climate events.

  13. An Alluvial Surface Chronology Based on Cosmogenic 36Cl Dating, Ajo Mountains (Organ Pipe Cactus National Monument), Southern Arizona

    Science.gov (United States)

    Liu, Beiling; Phillips, Fred M.; Pohl, Molly M.; Sharma, Pankaj

    1996-01-01

    A chronology of alluvial surfaces on piedmont slopes below the western Ajo Mountains, southern Arizona, has been obtained using cosmogenic 36Cl accumulation and AMS radiocarbon dating. The apparent 36Cl ages of individual boulders range from 520,000 to 13,000 yr, and the 14C ages of organic material in the two young terraces are 2750-2350 and 17,800 cal yr B.P. The sequence of 36Cl ages is consistent with the apparent stratigraphic order, but groupings of similar ages for different surfaces appear to result from repeated reworking of older surfaces associated with the deposition of younger ones. The youngest surface gave a distribution of 36Cl ages about 30,000 yr older than the 14C and soil ages; however, this distribution had 36Cl ages that overlapped with 36Cl ages from active channels and hillslopes. We attribute the older-than-expected exposure ages of sampled boulders to inheritance of 36Cl while residing near the surface during very slow erosion on the mountain front. Our results show that although cosmogenic nuclide accumulation can help establish chronologies for surfaces in piedmont settings, care must be used in evaluating the effects of complex exposure histories.

  14. Better late than never? Interannual and seasonal variability in breeding chronology of gentoo penguins at Stranger Point, Antarctica

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    Mariana A. Juáres

    2013-05-01

    Full Text Available Rapid climate change recorded in the western Antarctic Peninsula confronts species with less predictable conditions in the marine and terrestrial environments. We analysed the breeding chronology and nesting site selection of gentoo penguins (Pygoscelis papua at King George Island (Isla 25 de Mayo, Antarctica, during four seasons in which differences in snow presence and persistence on the ground were observed. We recorded an overall delay as well as seasonal asynchrony at the beginning of reproduction for those years with higher snow deposition. A redistribution of breeding groups was also observed. Nevertheless, the population breeding success and chicks’ weight at fledging remained relatively constant, despite the delay in breeding chronology, the increased duration of foraging trips during the guard stage and the decreased weight of stomach contents during the crèche stage. We suggest that the plasticity of their trophic biology, along with the flexibility of their breeding phenology and relocation of breeding groups, may be complementary reasons why gentoo penguin populations in the region have remained stable in spite of the changing conditions currently registered.

  15. Diffusion-Weighted MRI in Creutzfeldt-Jakob Disease: Focus on the Cerebral Cortex and Chronologic Change

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Eun; Song, Chang Joon; Lee, In Ho [Chungnam National University, Daejeon (Korea, Republic of); Yu, In Kyu [Eulji University Hospital, Seoul (Korea, Republic of); Choi, See Sung [Wonkwang University Hospital, Iksan (Korea, Republic of)

    2010-08-15

    To evaluate high cortical signal intensity and chronologic changes for diffusion-weighted MR imaging (DWI) in sporadic Creutzfeldt-Jakob disease. We retrospectively analyzed the DWI results of 16 patients with probable CJD (according to WHO criteria) and evaluated the distribution, extent and bilaterality of the lesions in the cortex, basal ganglia and thalamus. We also reviewed the chronologic changes of the lesions by evaluating the followup MR examination results in 8 of 16 patients. Cortical abnormalities were present in 15 (94%) of 16 patients. Isolated cortical involvement was present in 6 patients (40%), while the combined involvement of the cortex and basal ganglia was present in 9 patients (60%). The distribution of the lesions was bilateral in 12 patients and predominantly on the right side in 8 patients. Upon follow-up MR imaging, the cortical lesions showed progress in terms of extent and signal intensity. Basal ganglia abnormalities were present in 9 of 15 patients. Moreover, 4 of 6 patients who had no abnormal signal intensity in the basal ganglia on the initial MR imaging results, showed abnormally high signal intensity upon follow-up MR imaging. The characteristically high cortical signal intensities on DWI in an elderly patient with rapidly progressive dementia should point to the diagnosis of early phase CJD and might be useful for the differential diagnosis.

  16. Four new tree-ring chronologies from old black pine forests of Sandıras Mountain (Mugla, Turkey

    Directory of Open Access Journals (Sweden)

    Mehmet Doğan

    2015-07-01

    Full Text Available Sandıras Mountain is located in southwest of Gölgeli Mountain, which lies parallel to border of Aegean and Mediterranean Regions, in Southwestern Anatolia. This mountainous area is one of the natural distribution areas of black pine (Pinus nigra Arn. and has the oldest black pine communities in Turkey. Monumental black pine stands and the large number of individual monumental trees can be observed between the 1200 and 2000 m elevations of the mountain (especially north slope of the mountain. In this paper, we present preliminary results of a dendrochronological research on old black pine trees of Sandıras Mountain. Four new tree-ring chronologies were built from upper and lower elevations of south and north slopes of the mountain. The shortest and the longest chronologies were 241 and 820 years-long (obtained from upper elevation of the north slope, respectively. In this research, we record the most sensitive black pine trees (mean sensitivity value is 0.27 of Turkey from the north slope of Sandıras Mountain.

  17. Late Quaternary geomorphic history of a glacial landscape - new sedimentary and chronological data from the Cordillera de Cochabamba (Bolivia)

    Science.gov (United States)

    May, J.-H.; Preusser, F.; Zech, R.; Ilgner, J.; Veit, H.

    2009-04-01

    Throughout the Central Andes, glacial landscapes have long been used for the reconstruction of Late Quaternary glaciations and landscape evolution. Much work has focused on the Andes in Peru, Chile and the Bolivian Altiplano, whereas relatively little data has been published on glaciation history in the eastern Andean ranges and slopes. Even less is known with regard to the postglacial evolution of these glacial landscapes. In the Cordillera de Cochabamba (Bolivia), local maximum advances probably peaked around 20-25 ka BP and were followed by significant readvances between ~12-16 ka BP. This generally points to temperature controlled maximum glacial advances along the humid eastern slopes of the Central Andes, which is supported by glacier-climate-modelling studies. However, most studies include only marginal information with regard to the complex geomorphic and sedimentary situation in the Cordillera de Cochabamba. Furthermore, the chronological results are afflicted with several methodological uncertainties inherent to surface exposure dating and call for application of alternative, independent age dating methods. Therefore this study aims at i) documenting and interpreting the complex glacial geomorphology of the Huara Loma valley in the Cordillera de Cochabamba (Bolivia), ii) analyzing the involved units of glacial sediments, and iii) improving the chronological framework by applying optically stimulated luminescence (OSL) and radiocarbon dating (14C). For this purpose, geomorphic mapping was combined with field documentation of sedimentary profiles. The involved sediments were subject to geochemical and mineralogical analysis in order to deduce information on their erosional and weathering histories. In addition, the interpretation of OSL ages from glacial and proglacial sediments integrated several methodological procedures with regard to sample preparation and statistical analysis of the measurements in order to increase the degree of confidence. These

  18. Dental modifications: a perspective of Indonesian chronology and the current applications

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    Rusyad Adi Suriyanto

    2010-06-01

    Full Text Available Background: Dental modifications are one of the forms of initiation rite. Thus tradition can be found in all of Indonesian regions, even in South East Asia, in previous era. Modes and dentistry, as a culture product, including its modifications or decorations toward body and teeth have appeared in present day, such as tattoo and decorations on teeth which are taken particular model and superimpose or inculcate ornament of jewel, diamond, gold and others. The first research aim is to describe how functions of modifications on teeth represent cultural affinity and population of biologic affinity that accompany it from time to time; starting from prehistoric period to present day, especially in Indonesian region. The second aim is to submit applicable proposal that is useful for medical area, particularly in dentistry. Method: The research materials include teeth of the adult human skulls of Java, Balinese, and East Nusa Tenggara from some paleoanthropological–archaeological sites, as well as isolated permanent dental sample from modern Balinese population. The methods used are visual comparative descriptive method, and browsed through ethnographic and archaeological classic literatures. Result: Chronologically, dental modifications as reference to the pattern of migration and the domination of the culture in the past, and these facts indicate to the biological affinity and indicate to how the culture influences other culture. Conclusion: Some effects of the practices of dental modifications are the emergence of some diseases. Therefore, it is necessary for the agent of health and the traditional practitioner to be aware when they practice the dental modifications. Nevertheless, on the other side, based on explanations the research results, it is clear that dental modifications provide broader knowledge, because it has a very long journey of migration history, occupancy, and culture in this Indonesian Archipelago, which stretches from the period

  19. Sources and chronology of nitrate contamination in spring waters, Suwannee River basin, Florida

    Science.gov (United States)

    Katz, Brian G.; Hornsby, H.D.; Bohlke, J.F.; Mokray, M.F.

    1999-01-01

    A multi-tracer approach, which consisted of analyzing water samples for n aturally occurring chemical and isotopic indicators, was used to better understand sources and chronology of nitrate contamination in spring wate rs discharging to the Suwannee and Santa Fe Rivers in northern Florida. Dur ing 1997 and 1998, as part of a cooperative study between the Suwannee River Water Management District and the U.S. Geological Survey, water samples were collected and analyzed from 24 springs and two wells for major ions, nutrients, dissolved organic carbon, and selected environmental isotopes [18O/16O, D/H, 13C/12C, 15N/14N]. To better understand when nitrate entered the ground-water system, water samples were analyzed for chlorofluorocarbons (CFCs; CCl3F, CCl2F2, and C2Cl3F3) and tritium (3H); in this way, the apparent ages and residence times of spring waters and water from shallow zones in the Upper Floridan aquifer were determined. In addition to information obtained from the use of isotopic and other chemical tracers, information on changes in land-use activities in the basin during 1954-97 were used to estimate nitrogen inputs from nonpoint sources for five counties in the basin. Changes in nitrate concentrations in spring waters with time were compared with estimated nitrogen inputs for Lafayette and Suwannee Counties. Agricultural activities [cropland farming, animal farming operations (beef and dairy cows, poultry, and swine)] along with atmospheric deposition have contributed large quantities of nitrogen to ground water in the Suwannee River Basin in northern Florida. Changes in agricultural land use during the past 40 years in Alachua, Columbia, Gilchrist, Lafayette, and Suwannee Counties have contributed variable amounts of nitrogen to the ground-water system. During 1955-97, total estimated nitrogen from all nonpoint sources (fertilizers, animal wastes, atmospheric deposition, and septic tanks) increased continuously in Gilchrist and Lafayette Counties. In

  20. The Gothenburg geomagnetic excursion as a chronological marker for the Allerød interstadial in the Central Russian Upland

    Science.gov (United States)

    Gus'kova, E. G.; Raspopov, O. M.; Dergachev, V. A.; Iosifidi, A. G.; Sinitsyna, G. V.

    2012-12-01

    Palaeomagnetic investigations of deposits at the Baranova Gora archaeological site located near Volgo Lake (56.9°N, 33.2°E) in the Central Russian Upland have been carried out. The palaeomagnetic studies have revealed the development of the Gothenburg geomagnetic excursion dated at 13000-12350 BP. Revealing the Gothenburg excursion allowed us to use the findings of the palaeomagnetic investigations as a chronological benchmark, in addition to the results of palynological and archaeological (comparative analysis of archaeological artifacts) methods of dating the cultural layers of this archaeological monument, as well as to refine the time frame of the climatic Allerød interstadial in the Central Russian Upland. The data obtained in our study indicate that the Allerød interstadial in the Central Russian Upland began several hundred years before 12000 BP, the date commonly believed to be the beginning of the Allerød interstadial.

  1. Towards consistent chronology in the early Solar System: high resolution 53Mn-53Cr chronometry for chondrules.

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Q; Jacobsen, B; Moynier, F; Hutcheon, I D

    2007-05-02

    New high-precision {sup 53}Mn-{sup 53}Cr data obtained for chondrules extracted from a primitive ordinary chondrite, Chainpur (LL3.4), define an initial {sup 53}Mn/{sup 55}Mn ratio of (5.1 {+-} 1.6) x 10{sup -6}. As a result of this downward revision from an earlier higher value of (9.4 {+-} 1.7) x 10{sup -6} for the same meteorite (Nyquist et al. 2001), together with an assessment of recent literature, we show that a consistent chronology with other chronometers such as the {sup 26}Al-{sup 26}Mg and {sup 207}Pb-{sup 206}Pb systems emerges in the early Solar System.

  2. Do not mess with time: Probing faster than light travel and chronology protection with superluminal warp drives

    CERN Document Server

    Liberati, Stefano

    2016-01-01

    While General Relativity ranks undoubtedly among the best physics theories ever developed, it is also among those with the most striking implications. In particular, General Relativity admits solutions which allow faster than light motion and consequently time travel. Here we shall consider a "pre-emptive" chronology protection mechanism that destabilises superluminal warp drives via quantum matter back-reaction and hence forbids even the conceptual possibility to use these solutions for building a time machine. This result will be considered both in standard quantum field theory in curved spacetime as well as in the case of a quantum field theory with Lorentz invariance breakdown at high energies. Some lessons and future perspectives will be finally discuss.

  3. A Chronology of Attacks on and Unlawful Interferences with, Offshore Oil and Gas Installations, 1975 – 2010

    Directory of Open Access Journals (Sweden)

    Mikhail Kashubsky

    2011-12-01

    Full Text Available Throughout its history, the oil and gas industry has been a subject of environmental protests, labour disputes, tensions with local communities, and it has also been a target of various violent activities ranging from vandalism to political violence, which have impinged on the security of oil industry workers and interfered with operational activities of oil companies on numerous occasions. Although a considerable number of attacks on oil and gas infrastructure occurred over the course of the industry’s existence, most of those attacks were directed against onshore petroleum targets. Compared to onshore petroleum infrastructure, attacks on offshore oil and gas installations are relatively rare. The following chronology provides details of attacks, unlawful interferences, and security incidents involving offshore oil and gas installations that happened between 1975 and 2010. 

  4. A reevaluation of the Pallett Creek earthquake chronology based on new AMS radiocarbon dates, San Andreas fault, California

    Science.gov (United States)

    Scharer, K.M.; Biasi, G.P.; Weldon, R.J.

    2011-01-01

    The Pallett Creek paleoseismic record occupies a keystone position in most attempts to develop rupture histories for the southern San Andreas fault. Previous estimates of earthquake ages at Pallett Creek were determined by decay counting radiocarbon methods. That method requires large samples which can lead to unaccounted sources of uncertainty in radiocarbon ages because of the heterogeneous composition of organic layers. In contrast, accelerator mass spectrometry (AMS) radiocarbon dates may be obtained from small samples that have known carbon sources and also allow for a more complete sampling of the section. We present 65 new AMS radiocarbon dates that span nine ground-rupturing earthquakes at Pallett Creek. Overall, the AMS dates are similar to and reveal no dramatic bias in the conventional dates. For many layers, however, individual charcoal samples were younger than the conventional dates, leading to earthquake ages that are overall slightly younger than previously reported. New earthquake ages are determined by Bayesian refinement of the layer ages based on stratigraphic ordering and sedimentological constraints. The new chronology is more regular than previously published records in large part due to new samples constraining the age of event R. The closed interval from event C to 1857 has a mean recurrence of 135years (?? = 83.2 years) and a quasiperiodic coefficient of variation (COV) of 0.61. We show that the new dates and resultant earthquake chronology have a stronger effect on COV than the specific membership of this long series and dating precision improvements from sedimentation rates. Copyright 2011 by the American Geophysical Union.

  5. Long tree-ring chronologies provide evidence of recent tree growth decrease in a Central African tropical forest.

    Directory of Open Access Journals (Sweden)

    Giovanna Battipaglia

    Full Text Available It is still unclear whether the exponential rise of atmospheric CO2 concentration has produced a fertilization effect on tropical forests, thus incrementing their growth rate, in the last two centuries. As many factors affect tree growth patterns, short -term studies might be influenced by the confounding effect of several interacting environmental variables on plant growth. Long-term analyses of tree growth can elucidate long-term trends of plant growth response to dominant drivers. The study of annual rings, applied to long tree-ring chronologies in tropical forest trees enables such analysis. Long-term tree-ring chronologies of three widespread African species were measured in Central Africa to analyze the growth of trees over the last two centuries. Growth trends were correlated to changes in global atmospheric CO2 concentration and local variations in the main climatic drivers, temperature and rainfall. Our results provided no evidence for a fertilization effect of CO2 on tree growth. On the contrary, an overall growth decline was observed for all three species in the last century, which appears to be significantly correlated to the increase in local temperature. These findings provide additional support to the global observations of a slowing down of C sequestration in the trunks of forest trees in recent decades. Data indicate that the CO2 increase alone has not been sufficient to obtain a tree growth increase in tropical trees. The effect of other changing environmental factors, like temperature, may have overridden the fertilization effect of CO2.

  6. Chronological dating and tectonic implications of late Cenozoic volcanic rocks and lacustrine sequence in Oiyug Basin of southern Tibet

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Reconstruction of uplift history of the Tibetan Plateau is crucial for understanding its environmental impacts. The Oiyug Basin in southern Tibet contains multiple periods of sedimentary sequences and volcanic rocks that span much of the Cenozoic and has great potential for further studying this issue. However, these strata were poorly dated. This paper presents a chronological study of the 145 m thick and horizontally-distributed lacustrine sequence using paleomagnetic method as well as a K-Ar dating of the underlying volcanic rocks. Based on these dating results, a chronostratigraphic framework and the basin-developmental history have been established for the past 15 Ma, during which three tectonic stages are identified. The period of 15-8.1 Ma is characterized by intense volcanic activities involving at least three major eruptions. Subsequently, the basin came into a tectonically quiescent period and a lacustrine sedimentary sequence was developed. Around 2.5 Ma, an N-S fault occurred across the southern margin of the basin, leading to the disappearance of the lake environment and the development of the Oiyug River. The Gyirong basin on northern slope of the Himalayas shows a similar basin developmental history and thus there is a good agreement in tectonic activities between the Himalayan and Gangdise orogenic belts. Therefore, the tectonic evolution stages experienced by the Oiyug Basin during the past 15 Ma could have a regional significance for southern Tibet. The chronological data obtained from this study may provide some constraints for further studies with regard to the tectonic processes and environmental changes in southern Tibetan Plateau.

  7. IceChrono v1: a probabilistic model to compute a common and optimal chronology for several ice cores

    Directory of Open Access Journals (Sweden)

    F. Parrenin

    2014-10-01

    Full Text Available Polar ice cores provides exceptional archives of past environmental conditions. Dating ice and air bubbles/hydrates in ice cores is complicated since it involves different dating methods: modeling of the sedimentation process (accumulation of snow at surface, densification of snow into ice with air trapping and ice flow, use of dated horizons by comparison to other well dated targets (other dated paleo-archives or calculated variations of Earth's orbital parameters, use of dated depth intervals, use of Δdepth information (depth shift between synchronous events in the ice matrix and its air/hydrate content, use of stratigraphic links in between ice cores (ice-ice, air-air or mix ice-air links. Here I propose IceChrono v1, a new probabilistic model to combine these different kinds of chronological information to obtain a common and optimized chronology for several ice cores, as well as its confidence interval. It is based on the inversion of three quantities: the surface accumulation rate, the Lock-In Depth (LID of air bubbles and the vertical thinning function. IceChrono is similar in scope to the Datice model, but has differences on the mathematical, numerical and programming point of views. I apply IceChrono on two dating experiments. The first one is similar to the AICC2012 experiment and I find similar results than Datice within a few centuries, which is a confirmation of both IceChrono and Datice codes. The second experiment involves only the Berkner ice core in Antarctica and I produce the first dating of this ice core. IceChrono v1 is freely available under the GPL v3 open source license.

  8. "EDML1": a chronology for the EPICA deep ice core from Dronning Maud Land, Antarctica, over the last 150 000 years

    Directory of Open Access Journals (Sweden)

    U. Ruth

    2007-08-01

    Full Text Available A chronology called EDML1 has been developed for the EPICA ice core from Dronning Maud Land (EDML. EDML1 is closely interlinked with EDC3, the new chronology for the EPICA ice core from Dome-C (EDC through a stratigraphic match between EDML and EDC that consists of 322 volcanic match points over the last 128 ka. The EDC3 chronology comprises a glaciological model at EDC, which is constrained and later selectively tuned using primary dating information from EDC as well as from EDML, the latter being transferred using the tight stratigraphic link between the two cores. Finally, EDML1 was built by exporting EDC3 to EDML. For ages younger than 41 ka BP the new synchronized time scale EDML1/EDC3 is based on dated volcanic events and on a match to the Greenlandic ice core chronology GICC05 via 10Be and methane. The internal consistency between EDML1 and EDC3 is estimated to be typically ~6 years and always less than 450 years over the last 128 ka (always less than 130 years over the last 60 ka, which reflects an unprecedented synchrony of time scales. EDML1 ends at 150 ka BP (2417 m depth because the match between EDML and EDC becomes ambiguous further down. This hints at a complex ice flow history for the deepest 350 m of the EDML ice core.

  9. Recent advances in long-term climate and moisture reconstructions from the Baltic region: Exploring the potential for a new multi-millennial tree-ring chronology

    Science.gov (United States)

    Edvardsson, Johannes; Corona, Christophe; Mažeika, Jonas; Pukienė, Rutile; Stoffel, Markus

    2016-01-01

    This study presents the first results from an ongoing initiative to develop a multi-millennial Baltic tree-ring width (TRW) chronology consisting of 12 floating records from subfossil Scots pines (Pinus sylvestris L.) extracted from three Lithuanian peat-mining areas. The floating series have been complemented with absolutely dated TRW chronologies which were obtained from living trees growing in unmanaged and unexploited peatland areas adjacent to each of the above study sites. The subfossil material has been dated by radiocarbon and shows a temporal spread over the last 6000 years, with assemblages of trees during the Holocene Thermal Maximum (HTM; 8000-4000 BP) and the onset of the Medieval Warm Period (MWP, AD 900-1350). Annual tree growth and sample replication of peatland pines reflect moisture variations and long-term climate variability. The importance of extending the TRW chronologies should not therefore be underestimated as (1) climate records of comparable length and resolution do not exist for the Baltic region, but also as (2) a result of a widespread lack of detailed moisture proxies spanning several millennia. Our data clearly show that a 6000-yr, continuous pine chronology from the Baltic region is a realistic objective, and would doubtlessly fill a major geographic gap in an ecologically sensitive region located at the interface between the temperate and boreal vegetation zones.

  10. 三代年代学研究的新突破%New Breakthroughs in the Chronological Study of the Three Dynasties

    Institute of Scientific and Technical Information of China (English)

    殷玮璋

    2001-01-01

    Through four years of efforts, the "Xia-Shang-Zhou Chronology Project" has got new breakthroughs in the chronological study. For example, the conventional :4C-dating of the serial carbon samples from the pre-dynastic Zhou—initial Western Zhou—early Western Zhou--mid Western Zhou strata of the Feng-Hao site shows that Zhou King Wu Wang's conquering the Shang dynasty was within the limits of 1050--1020 BC; the carbon samples from Tomb 8 of the Jin Marquis graveyard are 14C-dated to 808 -+ 8 BC; the five lunar eclipses recorded in oracle inscriptions of the bin group, according to astronomers' calculation carried out with palaeographers' participation, indicate that Wu Ding's reign can be dated to 1250—1192 BC, corresponding to the results of 14C-dating for the Wu Ding period. The establishment of Xia, Shang and Zhou chronological framework will play an important role in the advance of Chinese chronological study and the development of related disciplines.

  11. Chronology of the late Turolian deposits of the Fortuna basin (SE Spain): implications for the Messinian evolution of the eastern Betics

    NARCIS (Netherlands)

    Garcés, Miguel; Krijgsman, W.; Agustí, Jorge

    2001-01-01

    The magnetostratigraphy of the mammal-bearing alluvial fan-fan delta sequences of the Fortuna basin (SE Spain) has yielded an accurate chronology for the late Turolian (Messinian) basin infill. From early to late Messinian (at least between 6.8 and 5.7 Ma), the Fortuna basin records the sedimentatio

  12. Refining 14C dating of bone >30,000 BP : establishing an accurate chronology for the Middle to Upper Palaeolithic transition in France.

    NARCIS (Netherlands)

    Talamo, Sahra

    2012-01-01

    This thesis aims to improve the chronology of the transition from the Middle to Upper Palaeolithic in France through the radiocarbon dating of bone collagen samples. This requires accurate calibration of the radiocarbon time scale for this time interval, reliable extraction of collagen from prehisto

  13. Home-based Early Intervention on Auditory and Speech Development in Mandarin-speaking Deaf Infants and Toddlers with Chronological Aged 7–24 Months

    Directory of Open Access Journals (Sweden)

    Ying Yang

    2015-01-01

    Conclusions: The data suggested the early hearing intervention and home-based habilitation benefit auditory and speech development. Chronological age and recovery time may be major factors for aural verbal outcomes in hearing impaired children. The development of auditory and speech in hearing impaired children may be relatively crucial in thefirst year's habilitation after fitted with the auxiliary device.

  14. Continuous earlywood vessels chronologies in floodplain ring-porous species can improve dendrohydrological reconstructions of spring high flows and flood levels

    Science.gov (United States)

    Kames, S.; Tardif, J. C.; Bergeron, Y.

    2016-03-01

    Plants respond to environmental stimuli through changes in growth and development. Characteristics of wood cells such as the cross-sectional area of vessel elements (hereafter referred to as vessels) may store information about environmental factors present at the time of vessel differentiation. The analysis of vessel characteristics therefore offers a different time resolution than annual ring width because vessels in tree rings differentiate within days to a few weeks. Little research has been conducted on the sensitivity of earlywood vessels in ring-porous species in response to flooding. The general objectives of this study were to determine the plasticity of earlywood vessel to high flows and spring flooding in floodplain black ash (Fraxinus nigra Marsh.) trees and to assess the utility of developing continuous earlywood vessel chronologies in dendrohydrological reconstruction. In contrast, most dendrohydrological studies until now have mainly used vessel anomalies (flood rings) as discrete variables to identify exceptional flood events. The study area is located in the boreal region of northwestern Québec. Vessel and ring-width chronologies were generated from F. nigra trees growing on the floodplain of Lake Duparquet. Spring discharge had among all hydro-climatic variables the strongest impact on vessel formation and this signal was coherent spatially and in the frequency domain. The mean vessel area chronology was significantly and negatively correlated to discharge and both the linearity and the strength of this association were unique. In floodplain F. nigra trees, spring flooding promoted the formation of more abundant but smaller earlywood vessels. Earlywood vessels chronologies were also significantly associated with other hydrological indicators like Lake Duparquet's ice break-up date and both ice-scar frequency and height chronologies. These significant relationships stress the utility of developing continuous vessels chronologies for hydrological

  15. On the chronology of lunar origin and evolution. Implications for Earth, Mars and the Solar System as a whole

    Science.gov (United States)

    Geiss, Johannes; Rossi, Angelo Pio

    2013-11-01

    An origin of the Moon by a Giant Impact is presently the most widely accepted theory of lunar origin. It is consistent with the major lunar observations: its exceptionally large size relative to the host planet, the high angular momentum of the Earth-Moon system, the extreme depletion of volatile elements, and the delayed accretion, quickly followed by the formation of a global crust and mantle. According to this theory, an impact on Earth of a Mars-sized body set the initial conditions for the formation and evolution of the Moon. The impact produced a protolunar cloud. Fast accretion of the Moon from the dense cloud ensured an effective transformation of gravitational energy into heat and widespread melting. A "Magma Ocean" of global dimensions formed, and upon cooling, an anorthositic crust and a mafic mantle were created by gravitational separation. Several 100 million years after lunar accretion, long-lived isotopes of K, U and Th had produced enough additional heat for inducing partial melting in the mantle; lava extruded into large basins and solidified as titanium-rich mare basalt. This delayed era of extrusive rock formation began about 3.9 Ga ago and may have lasted nearly 3 Ga. A relative crater count timescale was established and calibrated by radiometric dating (i.e., dating by use of radioactive decay) of rocks returned from six Apollo landing regions and three Luna landing spots. Fairly well calibrated are the periods ≈4 Ga to ≈3 Ga BP (before present) and ≈0.8 Ga BP to the present. Crater counting and orbital chemistry (derived from remote sensing in spectral domains ranging from γ- and x-rays to the infrared) have identified mare basalt surfaces in the Oceanus Procellarum that appear to be nearly as young as 1 Ga. Samples returned from this area are needed for narrowing the gap of 2 Ga in the calibrated timescale. The lunar timescale is not only used for reconstructing lunar evolution, but it serves also as a standard for chronologies of the

  16. Extinction chronology of the woolly rhinoceros Coelodonta antiquitatis in the context of late Quaternary megafaunal extinctions in northern Eurasia

    Science.gov (United States)

    Stuart, Anthony J.; Lister, Adrian M.

    2012-09-01

    Megafaunal extinctions in northern Eurasia (excluding Mediterranean islands) since the Last Interglacial claimed about 37% of species with body weights >44 kg. Here we review the dating evidence for the timings of these extinctions, which were staggered over tens of millennia. Moreover, individual species disappeared at different times in different geographical areas. For example, cave bear probably disappeared ca. 30.5-28.5 ka, at approximately the onset of GS-3 (beginning of 'LGM'), whereas cave lion survived until the Lateglacial ca 14 ka. Others survived into the Holocene: woolly mammoth until ca 10.7 ka in the New Siberian Islands and ca 4 ka on Wrangel Island, giant deer to at least 7.7 ka in western Siberia and European Russia. It is evident that climatic and vegetational changes had major impacts on species' ranges, and moreover the contrasting chronologies and geographical range contractions are consistent with environmental drivers relating to their differing ecologies. However, the possible role of humans in this process has still to be satisfactorily explored. We present a detailed review of the radiocarbon record and extinction chronology of an exclusively northern Eurasian species, the woolly rhinoceros Coelodonta antiquitatis, an animal adapted to feeding on low-growing herbaceous vegetation and a dry climate with minimal snowfall. During the Last Glacial the overall (time-averaged) range of C. antiquitatis extended across most of northern Eurasia, but the species failed to reach North America. On the basis of 233 ultrafiltered AMS radiocarbon dates, together with 50 others which pass our auditing criteria, we reconstruct a detailed chronology for this species. C. antiquitatis was widespread over most of the time span covered by radiocarbon dating, but from ca 35 ka (calibrated) it apparently contracted towards the east, culminating in its probable extinction ca 14 ka, with the latest dates from north-eastern Siberia. It disappeared from Britain, at

  17. Chronology of Pliocene and Quaternary bioevents and climatic events from fission-track ages on tephra beds, Wairarapa, New Zealand

    Science.gov (United States)

    Shane, Phil; Froggatt, Paul; Black, Tasha; Westgate, John

    1995-02-01

    High-resolution Pliocene and Pleistocene sequences exposed on land in New Zealand are some of the few detailed records of widepread marine bioevents and paleoclimatic changes in the Southern Hemisphere. Marine biostratigraphy calibrated in deep-sea cores by paleomagnetic reversals has been the primary basis for the chronology of these sequences. We have determined ages for several tephra beds which now provide an independent numerical age calibration for a well-studied marine and terrestrial section in Wairarapa. By using the isothermal plateau fission track (ITPFT) method on volcanic glass we have overcome the problems of partial track fading and detrital mineral contamination, which hindered earlier studies, to reveal a new chronology extending back to nearly 5 Ma. Our ages for the Hikawera Tuff (4.91 ± 0.25 Ma) and Spooner Tuff (3.44 ± 0.13 Ma) are consistent with the appearance and disappearance of many early Pliocene foraminiferial species, validating their age calibration in New Zealand. However, some fossil occurrences, including coccoliths, differ temporally by as much as 0.55 Ma, perhaps due to local tectonic-induced recycling. Four Pleistocene tephra beds (Potaka tephra (1.00 ± 0.03 Ma), Kaukatea tephra (0.87 ± 0.05 Ma), Rangitawa tephra (ca. 0.35 Ma) and Kawakawa tephra (ca. 0.22 Ma)) are now recognised in the Wairarapa sequence via stratigraphic and new geochemical and age data. These beds allow direct correlation to other marine and terrestrial basins, as well as volcanic regions in New Zealand, and will ultimately aid in a regional paleoenvironmental reconstruction where bioevents are absent. The tephra ages indicate that the marine sediment accumulation rates varied from 90 to 250 m/Ma between different sections of the Pliocene and reached ca. 350 m/Ma in the last 2.4 Ma, when the sequence displays pronounced glacioeustatic cyclic deposition. In the terrestrial realm, the oldest loess in New Zealand is now constrained to between 1.00 and 0.87 Ma.

  18. Pre-aged plant waxes in tropical lake sediments and their influence on the chronology of molecular paleoclimate proxy records

    Science.gov (United States)

    Douglas, Peter M. J.; Pagani, Mark; Eglinton, Timothy I.; Brenner, Mark; Hodell, David A.; Curtis, Jason H.; Ma, Keith F.; Breckenridge, Andy

    2014-09-01

    Sedimentary records of plant-wax hydrogen (δDwax) and carbon (δ13Cwax) stable isotopes are increasingly applied to infer past climate change. Compound-specific radiocarbon analyses, however, indicate that long time lags can occur between the synthesis of plant waxes and their subsequent deposition in marginal marine sediments. The influence of these time lags on interpretations of plant-wax stable isotope records is presently unconstrained, and it is unclear whether such time lags also affect lacustrine sediments. We present compound-specific radiocarbon (14Cwax) data for n-alkanoic acid plant waxes (n-C26 to n-C32) from: (1) a sediment core from Lake Chichancanab, Yucatan Peninsula, Mexico, (2) soils in the Lake Chichancanab catchment, and (3) surface sediments from three other lakes in southeastern Mexico and northern Guatemala. 14Cwax ages in the surface sediments are consistently older than modern, and may be negatively correlated with mean annual precipitation and positively correlated with lake catchment area. 14Cwax ages in soils surrounding Lake Chichancanab increase with soil depth, consistent with deep, subsoil horizons being the primary source of lacustrine aged plant waxes, which are likely delivered to lake sediments through subsurface transport. Plant waxes in the Lake Chichancanab core are 350-1200 years older than corresponding ages of bulk sediment deposition, determined by 14C dates on terrestrial plant macrofossils in the core. A δDwax time series is in closer agreement with other regional proxy hydroclimate records when a plant-wax 14C age model is applied, as opposed to the macrofossil-based core chronology. Inverse modeling of plant-wax age distribution parameters suggests that plant waxes in the Lake Chichancanab sediment core derive predominantly from millennial-age soil carbon pools that exhibit relatively little age variance (<200 years). Our findings demonstrate that high-temporal-resolution climate records inferred from stable isotope

  19. Molecular Radiocarbon Dating of Tropical Lake Sediments: Insights into the Chronology of Leaf Wax Stable Isotope Records

    Science.gov (United States)

    Douglas, P. M.; Pagani, M.; Eglinton, T. I.; Brenner, M.; Curtis, J. H.; Hodell, D. A.

    2010-12-01

    Leaf wax δD and δ13C measurements in marine and lacustrine sediment cores are promising proxies for past climatic and environmental change. However, a number of studies of marine sediments indicate centennial to millennial scale offsets between the radiocarbon ages of leaf waxes and the age of surrounding sediments due to long-term storage of these lipids in soils. These offsets present a complication for the interpretation of leaf wax stable isotope records that has not been thoroughly addressed. We present leaf wax δD, δ13C and Δ14C values for a sediment core from Lake Chichancanab in southeastern Mexico. This lake was previously studied using mineralogical (gypsum) and carbonate isotopic (δ18O) climate proxies, which indicated a sequence of severe droughts from 750 to 1000 AD, coincident with the collapse of the Classic Maya civilization. A suite of leaf wax δD values was plotted against the original sediment core chronology, which was developed using radiocarbon dates on terrestrial macrofossils. The leaf wax results also indicated major hydrological variability over the past 3000 years, but were not temporally coherent with the other climate proxy records. Leaf wax radiocarbon ages are 400 to 1200 years older than terrestrial macrofossil radiocarbon ages from the same depths, suggesting that leaf waxes are retained in the watershed for extended periods prior to deposition in the lake. We fit a 2nd-order polynomial equation to the depth profile of leaf wax radiocarbon ages (r2 =0.99) and refit the leaf wax δD profile to this “leaf wax age model”. This approach yielded much greater coherence with mineralogical and carbonate isotopic proxy records, including evidence for a period of severe drought (35‰ D-enrichment) from 750 to 1000 A.D. Our results indicate that long-term storage of leaf waxes in drainage basin soils can lead to temporal inaccuracies in leaf wax stable isotope records. These inaccuracies, however, can be corrected using a

  20. Violet stimulated luminescence dating of quartz from Luochuan (Chinese loess plateau): Agreement with independent chronology up to ∼600 ka

    DEFF Research Database (Denmark)

    Ankjærgaard, C.; Guralnik, B.; Buylaert, Jan-Pieter;

    2016-01-01

    Luminescence dating at the Luochuan loess type (China) section is at present limited to ∼0.1 Ma using quartz blue light stimulated luminescence (BLSL), but can be extended back in time to ∼0.5 Ma by resorting to the more developmental post-infrared infrared stimulated luminescence (post-IR IRSL) ......-1800 Gy) would correspond to the ability to date sediment up to ∼1 Ma back in time, offering a remarkable advance over existing methods.......Luminescence dating at the Luochuan loess type (China) section is at present limited to ∼0.1 Ma using quartz blue light stimulated luminescence (BLSL), but can be extended back in time to ∼0.5 Ma by resorting to the more developmental post-infrared infrared stimulated luminescence (post-IR IRSL...... demonstrate that the Multi-Aliquot Additive-Dose (MAAD) protocol produces a VSL chronology at Luochuan which is in agreement with independent ages up to ∼0.6 Ma. For a more representative environmental dose rate of ∼2 Gy/ka (∼35% lower than at Luochuan), the documented range of MAAD-VSL sensitivity (200...

  1. Chronological constraints on Cordilleran Ice Sheet glaciomarine sedimentation from core MD02-2496 off Vancouver Island (western Canada)

    Science.gov (United States)

    Cosma, T. N.; Hendy, I. L.; Chang, A. S.

    2008-05-01

    Chronology based on 46 radiocarbon dates has been generated for MD02-2496, western Vancouver Island, Canada. Subsequent correlation between glaciomarine sedimentary sequences within the core and the terrestrial stratigraphy of the Cordilleran Ice Sheet for the last 50 ka provide new insight into Cordilleran Ice Sheet processes. Glaciomarine sedimentation associated with the most recent advance (Fraser Glaciation) of the Cordilleran Ice Sheet began at 30.5 cal kyr BP (˜25 14C kyr BP). Extremely high sedimentation rates indicate the ice sheet became proximal to the site at ˜19.5 cal kyr BP (16 14C kyr BP). Deposition of ice rafted detritus (IRD) began at ˜17 cal kyr BP (14 14C kyr BP), and abruptly terminated at ˜16.2 cal kyr BP (13.5 14C kyr BP) indicating rapid regional ice sheet retreat. A minor IRD event followed at ˜14.7 cal kyr BP (12.5 14C kyr BP). Glaciomarine sediment deposition abruptly ended at 10.2 cal kyr BP (˜8.8 14C kyr BP) with the resumption of biogenic sedimentation. The Olympia Interstade is represented by an interval of hemipelagic sedimentation between ˜43 and 31.5 ka. Prior to ˜45 ka sediment deposition is controlled by glaciomarine processes with evidence for a significant IRD event at ˜47 cal kyr BP (>41±1.06 14C kyr BP).

  2. Species differentiation on a dynamic landscape: shifts in metapopulation genetic structure using the chronology of the Hawaiian Archipelago

    Science.gov (United States)

    Roderick, George K.; Croucher, Peter J.P.; Vandergast, Amy G.; Gillespie, Rosemary G.

    2012-01-01

    Species formation during adaptive radiation often occurs in the context of a changing environment. The establishment and arrangement of populations, in space and time, sets up ecological and genetic processes that dictate the rate and pattern of differentiation. Here, we focus on how a dynamic habitat can affect genetic structure, and ultimately, differentiation among populations. We make use of the chronology and geographical history provided by the Hawaiian archipelago to examine the initial stages of population establishment and genetic divergence. We use data from a set of 6 spider lineages that differ in habitat affinities, some preferring low elevation habitats with a longer history of connection, others being more specialized for high elevation and/or wet forest, some with more general habitat affinities. We show that habitat preferences associated with lineages are important in ecological and genetic structuring. Lineages that have more restricted habitat preferences are subject to repeated episodes of isolation and fragmentation as a result of lava flows and vegetation succession. The initial dynamic set up by the landscape translates over time into discrete lineages. Further work is needed to understand how genetic changes interact with a changing set of ecological interactions amongst a shifting mosaic of landscapes to achieve species formation.

  3. ESR/U-series chronology of the Lower Palaeolithic palaeo-anthropological site of Visogliano, Trieste, Italy

    Energy Technology Data Exchange (ETDEWEB)

    Falgueres, C.; Bahain, J.J.; Yokoyama, Y. [CNRS, UMR 5198, Museum Natl Hist Nat, Dept Prehist, F-75013 Paris, (France); Tozzi, C.; Boschian, G. [Univ Pisa, Dipartimento Sci Archeol, I-56100 Pisa, (Italy); Dolo, J.M. [CEA Saclay, Lab Natl Henri Becquerel, F-91191 Gif Sur Yvette, (France); Mercier, N.; Valladas, H. [CEA, CNRS, Lab Sci Climat and Environm, F-91198 Gif Sur Yvette, (France)

    2008-07-01

    The Visogliano shelter, in north-eastern Italy, is an important Middle Pleistocene occupation site where human remains were found together with an archaic lithic industry, including choppers, chopping tools and a few proto-bifaces. It is of utmost importance to try to document this period, when a second wave of settlement colonised Western Europe, carrying new flaking techniques and tools. Combined ESR/U-series analyses, integrated with bio-stratigraphical and environmental data, define a chronological frame for the layers from which the artefacts were unearthed. The lower levels, including human remains, can be dated to the 350-500 kyr time span, in agreement with micro-mammal and stratigraphical studies. These data make Visogliano one of the oldest palaeo-anthropological sites in Italy, where human remains are directly associated with proto-bifaces, choppers and chopping tools. In Western Europe, Visogliano is contemporaneous to the G soil of the Arago Cave, France, with which it shares several similarities in faunal assemblages and radiometric data, and which contains human remains also. These data make Visogliano as one of the oldest sites in Europe where the Acheulian culture is observed. (authors)

  4. Chronology and origin of Au-Cu deposits related to Paleozoic intracontinental rifting in West Tianshan Mountains, NW China

    Institute of Scientific and Technical Information of China (English)

    李华芹; 陈富文

    2002-01-01

    Located between the Tarim platform and Junggar massif, the West Tianshan intracontinental rift abuts against the China-Kazakhstan boundary in the west part, borders on the Yilianhabierga late Paleozoic relic ocean basin and the South Tianshan late Paleozoic ocean basin respectively in the northeast separated by the Aibi Lake fault and in the southeast by the fault along the southern margin of the Yili massif. During the development and after the close of the West Tianshan intracontinental rifting in the Carboniferous-Permian period, a series of nonferrous and precious metal mineralizations occurred with the Au-Cu deposits being the most important. Isotopic chronologic study of representative deposits of different types shows that gold-copper mineralization in the West Tianshan intracontinental rift zone mainly happened during the middle-late Hercynian Period, among which the Axi volcanic hydrothermal type gold deposit was formed during the Carboniferous with a fluid inclusion Rb-Sr isochron age of (339 ± 28) Ma; the Qiabukanzhuota quartzolite type gold deposit has a Rb-Sr isochron age of (312 ± 46) Ma; the Tawuerbieke porphyry type gold deposit has a Rb-Sr isochron age of (295 ± 16) Ma; the Jingbulak magmatic liquation Cu-Ni deposit and the Musizaote porphyry type Cu deposit have the forming ages of 300 Ma ± and 250 Ma ±, respectively. Analyses of crustal evolution and metallogenetic geological backgrounds of Au-Cu mineralizations in the studied area shows a close correlation with the rifting.

  5. Chronological observation in early radiation myelopathy of the cervical spinal cord; Gadolinium-enhanced MRI findings in two cases

    Energy Technology Data Exchange (ETDEWEB)

    Hirota, Saeko; Yoshida, Shoji; Soejima, Toshinori (Hyogo Medical Center for Adults, Akashi (Japan)) (and others)

    Gd-enhanced MR images of two patients with clinically and histopathologically diagnosed chronic progressive radiation myelitis (CPRM) were observed chronologically. One of them had had nasopharyngeal cancer and received radiotherapy at a dose of 100 Gy to the C1-2 level of the spinal cord. She developed CPRM 25 months after the termination of radiotherapy. The other had had malignant lymphoma originating from the tonsil and received chemoradiotherapy. The dose delivered to her cervical spinal cord was 40 Gy, and she developed CPRM 30 months later. Gd-enhanced MRI in the early phase revealed a small crescent-shaped nidus with or without a very small central nonenhanced area in both cases. Enhancement was not great. At that time, patients noticed only the inability to perceive pain and temperature or paresthesia in the opposite side. In a few months, MRI revealed a much more strongly enhanced and larger nidus with enlargement of a central nonenhanced area accompanied by long segmental cord enlargement. The patients' neurological symptoms had also progressed, with hemiparesis developing, for example. (author).

  6. The so-called "Pre-Levantine" phase and the chronology of the Levantine Rock Painting. A critical review

    Directory of Open Access Journals (Sweden)

    Mateo Saura, Miguel Ángel

    2002-06-01

    Full Text Available The rejection of the principles on which the so-called "prelevantine phase" is based and the discussion about the neolithic material culture parallels for levantine art allow its attribution to Epipaleolithic groups of hunters and gatherers. In the same way, the data on the process of transition between the Epipaleolithic and the Neolithic, and the relationship between the levantine style and the schematic rock painting seem to support a pre-neolithic chronology of the levantine art, related to non-producing ways of living.

    El rechazo de las bases en las que se sustenta la llamada "fase pre-levantina" y la discusión de los paralelos mobiliares neolíticos propuestos para el arte levantino dejan expedito el camino para su adscripción a los grupos de cazadores y recolectores epipaleolíticos. Asimismo, los datos con que contamos sobre el proceso de transición Epipaleolítico/Neolítico, y la relación entre el estilo levantino y la pintura rupestre esquemática parecen abogar también por una cronología pre-neolítica de lo levantino, asociado a unos modos de vida no productores.

  7. Sedimentology and Chronology of Paleogene Coarse Clastic Rocks in East-Central Tibet and Their Relationship to Early Tectonic Uplift

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jiangyu; WANG Jianghai; K. H. BRIAN; A. YIN; M. S. MATTHEW

    2007-01-01

    A systematic sedimentological and chronological study of typical Paleogene basins in eastcentral Tibet suggests that the depositional characteristics of extensively developed huge-bedded,purplish-red coarse clastic rocks formed in a tectonic setting of regional thrusting and strike-slipping represent a typical dry and hot subaerial alluvial fan environment formed in a proximal and rapidaccumulating sediment body in debris flows and a fan-surface braided river. Combining results from basin-fill sequences, sequences of coarse clastic rocks, fauna and sporo-pollen associations and thermochronological data, it is concluded that the coarse clastic rocks formed in the period of 54.2-belt), middle (Batang-Lijiang fault belt), and disintegration of large basins in the southern (LanpingSimao fold belt) segments of Tibet. The widespread massive-bedded coarse clastic rocks, fold thrusting and strike-slip, thrust shortening, and igneous activities in the Paleogene basins of eastcentral Tibet indicate that an early diachronous tectonic uplift might have occurred in the Tibetan Plateau from Middle Eocene to Oligocene, related to the initial stage of collision of the Indian and Asian plates.

  8. Importance of Maternal Diabetes on the Chronological Deregulation of the Intrauterine Development: An Experimental Study in Rat

    Science.gov (United States)

    Salazar García, Marcela; Reyes Maldonado, Elba; Revilla Monsalve, María Cristina; Villavicencio Guzmán, Laura; Reyes López, Alfonso; Sánchez-Gómez, Concepción

    2015-01-01

    We investigated whether maternal diabetes induced in rats using streptozotocin (STZ) on Day 5 of pregnancy affects the intrauterine developmental timeline. A total of 30 pregnant Sprague-Dawley diabetic rats (DRs) and 20 control rats (CRs) were used to obtain 21-day fetuses (F21) and newborn (NB) pups. Gestational age, weight, and body size were recorded as were the maxillofacial morphometry and morphohistological characteristics of the limbs. In DRs, pregnancy continued for ∼1.7 days, and delivery occurred 23 days postcoitus (DPC). In this group, the number of pups was lower, and 13% had maxillofacial defects. F21 in the DR group had lower weights and were smaller; moreover, the morphological characteristics of the maxillofacial structures, derived from the neural crest, were discordant with their chronological gestational age, resembling 18- to 19-day-old fetuses. These deficiencies were counterbalanced in NB pups. We conclude that hyperglycemia, which results from maternal diabetes and precedes embryo implantation, deregulates the intrauterine developmental timeline, restricts embryo-fetal growth, and primarily delays the remodeling and maturation of the structures derived from neural crest cells. PMID:25756053

  9. Stratification of yeast cells during chronological aging by size points to the role of trehalose in cell vitality.

    Science.gov (United States)

    Svenkrtova, Andrea; Belicova, Lenka; Volejnikova, Andrea; Sigler, Karel; Jazwinski, S Michal; Pichova, Alena

    2016-04-01

    Cells of the budding yeast Saccharomyces cerevisiae undergo a process akin to differentiation during prolonged culture without medium replenishment. Various methods have been used to separate and determine the potential role and fate of the different cell species. We have stratified chronologically-aged yeast cultures into cells of different sizes, using centrifugal elutriation, and characterized these subpopulations physiologically. We distinguish two extreme cell types, very small (XS) and very large (L) cells. L cells display higher viability based on two separate criteria. They respire much more actively, but produce lower levels of reactive oxygen species (ROS). L cells are capable of dividing, albeit slowly, giving rise to XS cells which do not divide. L cells are more resistant to osmotic stress and they have higher trehalose content, a storage carbohydrate often connected to stress resistance. Depletion of trehalose by deletion of TPS2 does not affect the vital characteristics of L cells, but it improves some of these characteristics in XS cells. Therefore, we propose that the response of L and XS cells to the trehalose produced in the former differs in a way that lowers the vitality of the latter. We compare our XS- and L-fraction cell characteristics with those of cells isolated from stationary cultures by others based on density. This comparison suggests that the cells have some similarities but also differences that may prove useful in addressing whether it is the segregation or the response to trehalose that may play the predominant role in cell division from stationary culture.

  10. Revised Chronology for the Mio-Pliocene Successions of the Eastern Paratethys: Towards a Better Understanding of Paleoenvironmental Change

    Science.gov (United States)

    Krijgsman, W.; Chang, L.; Baak, C. V.; Palcu, D.; Vasiliev, I.

    2014-12-01

    Paratethys is a large epicontinental sea, stretching from Germany to China at the beginning of the Oligocene (~34 Myr ago), that progressively retreated by a complex combination of basin infill, glacio-eustatic sea-level lowering and tectonic uplift to its present-day remnants: Black Sea, Caspian Sea and Aral Lake. Paratethys experienced major paleoenvironmental changes towards anoxic, hypersaline, and fresh water conditions. An accurate geological time scale (GTS) is crucial to understand the timing and rates of these change and to determine the underlying mechanisms. Geological time scales for the Paratethys region are notoriously controversial and encompass mainly regional stages, which are all defined on the basis of characteristic faunal assemblages (mainly mollusks and ostracods) endemic to the Paratethys Sea. During the last decade, we have performed numerous integrated magneto-biostratigraphic studies on the Mio-Pliocene sedimentary successions of the Eastern Paratethys, which resulted in revised chronological frameworks for the Dacian, Black Sea and Caspian Sea basins. This allows high-resolution stratigraphic correlations between the individual Paratethys subbasins and with the Mediterranean successions and help to better understand the dramatic paleoenvironmental changes in the region, such as the Messinian Salinity Crisis. Rock magnetic analyses of the sedimentary sequences of the Paratethys indicate that greigite is the main magnetic carrier and that a range of magnetic properties cannot be explained by the presence of diagenetic greigite, but are instead consistent with those expected for a biogenetic (bacterial) origin.

  11. North Atlantic ecosystem shifts revealed by cod otolith δ15N and δ13C chronologies

    DEFF Research Database (Denmark)

    Pedersen, Jens Brøgger; Nielsen, Jens Munk; Steingrund, Petur;

    Changes in climate and exploitation have caused large fluctuations in the productivity of many North Atlantic cod populations and the collapse of many cod fisheries. These fluctuations are most likely due to a combined effect of physical processes and changes in ecosystem trophic structure. To...... study the link between environmental changes and ecosystem trophic structure we developed δ15N and δ13C chronologies by analyzing the organic matrix of cod otoliths from the Faroe Shelf cod population (1950-2010) and the Nuuk Fjord cod population (1927-2009). Significant correlations between δ15N & δ13C...... annual mean values over time were seen in both ecosystems, suggesting δ15N & δ13C values were affected by the same overall processes. There were significant effects of climate variables (temperature, Atlantic Multi-decadal Oscillation (AMO) and Sub Polar Gyre index) on δ15N and δ13C chronologies in both...

  12. Attitudes towards ads and age. A study in seniors. The combination of chronological and cognitive age as an effective predictive criterion of attitudes

    OpenAIRE

    Moliner Tena, Miguel Ángel; Estrada Guillén, Marta; Monferrer Tirado, Diego; Sánchez García, Javier

    2014-01-01

    Older adults make up one of the markets with the greatest potential in the future. It is essential that businesses take the diversity within this group into account, and perform segmentation in order to obtain a favorable attitude towards the ad. The potential for segmentation by chronological age has been called into question in recent years, with cognitive age emerging as the main alternative. This research aims to analyses the relationship between the variables of attitude towards the ad, ...

  13. Aligning and synchronization of MIS5 proxy records from Lake Ohrid (FYROM) with independently dated Mediterranean archives: implications for DEEP core chronology

    OpenAIRE

    Zanchetta, Giovanni; Regattieri, Eleonora; Giaccio, Biagio; Wagner, Bernd; Sulpizio, Roberto; Francke, Alex; Vogel, Hendrik; Sadori, Laura; Masi, Alessia; Sinopoli, Gaia; Lacey, Jack H.; Leng, Melanie J.; Leicher, Niklas

    2016-01-01

    The DEEP site sediment sequence obtained during the ICDP SCOPSCO project at Lake Ohrid was dated using tephrostratigraphic information, cyclostratigraphy, and orbital tuning through the marine isotope stages (MIS) 15-1. Although this approach is suitable for the generation of a general chronological framework of the long succession, it is insufficient to resolve more detailed palaeoclimatological questions, such as leads and lags of climate events between marine and terrestr...

  14. Aligning and synchronization of MIS5 proxy records from Lake Ohrid (FYROM) with independently dated Mediterranean archives: implications for DEEP core chronology

    Science.gov (United States)

    Zanchetta, Giovanni; Regattieri, Eleonora; Giaccio, Biagio; Wagner, Bernd; Sulpizio, Roberto; Francke, Alex; Vogel, Hendrik; Sadori, Laura; Masi, Alessia; Sinopoli, Gaia; Lacey, Jack H.; Leng, Melanie J.; Leicher, Niklas

    2016-05-01

    The DEEP site sediment sequence obtained during the ICDP SCOPSCO project at Lake Ohrid was dated using tephrostratigraphic information, cyclostratigraphy, and orbital tuning through the marine isotope stages (MIS) 15-1. Although this approach is suitable for the generation of a general chronological framework of the long succession, it is insufficient to resolve more detailed palaeoclimatological questions, such as leads and lags of climate events between marine and terrestrial records or between different regions. Here, we demonstrate how the use of different tie points can affect cyclostratigraphy and orbital tuning for the period between ca. 140 and 70 ka and how the results can be correlated with directly/indirectly radiometrically dated Mediterranean marine and continental proxy records. The alternative age model presented here shows consistent differences with that initially proposed by Francke et al. (2015) for the same interval, in particular at the level of the MIS6-5e transition. According to this new age model, different proxies from the DEEP site sediment record support an increase of temperatures between glacial to interglacial conditions, which is almost synchronous with a rapid increase in sea surface temperature observed in the western Mediterranean. The results show how a detailed study of independent chronological tie points is important to align different records and to highlight asynchronisms of climate events. Moreover, Francke et al. (2016) have incorporated the new chronology proposed for tephra OH-DP-0499 in the final DEEP age model. This has reduced substantially the chronological discrepancies between the DEEP site age model and the model proposed here for the last glacial-interglacial transition.

  15. Chronology of the late Turolian deposits of the Fortuna basin (SE Spain): implications for the Messinian evolution of the eastern Betics

    OpenAIRE

    Garcés, Miguel; Krijgsman, W.; Agustí, Jorge

    2001-01-01

    The magnetostratigraphy of the mammal-bearing alluvial fan-fan delta sequences of the Fortuna basin (SE Spain) has yielded an accurate chronology for the late Turolian (Messinian) basin infill. From early to late Messinian (at least between 6.8 and 5.7 Ma), the Fortuna basin records the sedimentation of alluvial-palustrine deposits over a confined shallow basin. Changing environmental conditions in the latest Messinian are illustrated by the retreat of palustrine facies. A rapid progradation ...

  16. Index to Nuclear Safety. A technical progress review by chronology, permuted title, and author. Vol. 11, No. 1--Vol. 17, No. 6

    Energy Technology Data Exchange (ETDEWEB)

    Cottrell, W.B.; Klein, A.

    1977-02-23

    This index to Nuclear Safety covers articles in Nuclear Safety Vol. 11, No. 1 (Jan.-Feb. 1970), through Vol. 17, No. 6 (Nov.-Dec. 1976). The index includes a chronological list of articles (including abstract) followed by KWIC and Author Indexes. Nuclear Safety, a bimonthly technical progress review prepared by the Nuclear Safety Information Center, covers all safety aspects of nuclear power reactors and associated facilities. The index lists over 350 technical articles in the last six years of publication.

  17. Index to Nuclear Safety. A technical progress review by chronology, permuted title, and author. Vol. 11, No. 1--Vol. 17, No. 6

    International Nuclear Information System (INIS)

    This index to Nuclear Safety covers articles in Nuclear Safety Vol. 11, No. 1 (Jan.-Feb. 1970), through Vol. 17, No. 6 (Nov.-Dec. 1976). The index includes a chronological list of articles (including abstract) followed by KWIC and Author Indexes. Nuclear Safety, a bimonthly technical progress review prepared by the Nuclear Safety Information Center, covers all safety aspects of nuclear power reactors and associated facilities. The index lists over 350 technical articles in the last six years of publication

  18. Pathophysiological factors in the relationship between chronological age and calculated lung age as detected in a screening setting in community-dwelling subjects

    Directory of Open Access Journals (Sweden)

    Peter eKardos

    2016-02-01

    Full Text Available Aim: To explore the relationship between pathophysiological factors and premature lung ageing in a cohort of community-dwelling subjects in a health-screening setting. Methods: 16,107 pharmacy customers in Germany (5954 males, 10153 females; mean age 59.7 years participated in a lung function screening project by providing demographic data including smoking status and known airway conditions and performing spirometry with a Vitalograph, a spirometry screening device. Lung age was calculated from the spirometric findings, and the difference between chronological age and calculated lung age was analyzed in its relationship to the demographic data in general linear models. Results: In the overall cohort, calculated lung age exceeded chronological age by 10.0 years. Based on the subset of non-smokers not reporting any airway conditions, Vitalograph data in this setting may underestimate FEV1 to some degree but this apparently had little impact on the detection of association of lung age with pathophysiological factors or the corresponding effect sizes. The most important factors associated with greater lung age based on strength of association were presence of dyspnea, being a smoker and reporting a history of COPD or asthma. Corresponding effect sizes for the difference between age and lung age were 6.5, 5.7, 13.9 and 8.3 years over the chronological age. Discussion and Conclusions: These data confirm the usefulness of screening devices of lung function testing for epidemiological but potentially also for pharmaco-epidemiological studies.

  19. Establishment of tree-ring chronology and climatic response of Tibetan juniper(S.tibetica) in south Tibet,western China

    Institute of Scientific and Technical Information of China (English)

    Dmitry; M.Sonechkin

    2010-01-01

    A tree-ring width chronology of 442 years(1567-2008) was developed from Tibetan junipers(S.tibetica) derived from south Tibet in western China.Three versions of chronology were produced according to standard dendrochronological techniques.The correlation and response analysis displays a high correlation between the standard tree ring-width chronology and observed annual mean precipitation series during the period 1961-2008.Based on a linear regression model,an annual(prior August to current July) precipitation for the past 229 years was reconstructed.This is the first well-calibrated precipitation reconstruction for the Nanggarze region,south Tibet.The results show that relatively wet years with above-average precipitation occurred in 1780-1807,1854-1866,1886-1898,1904-1949,1967-1981 and 2000-2008,whereas relatively dry years with below-average precipitation prevailed during 1808-1853,1867-1885,1899-1903,1950-1966 and 1982-1999.Common dry/wet periods during 1890s,1910s,1940s-1960s and 1980s were also identified from other moisture reconstructions of nearby regions,indicating a synchronous climatic variation in south Tibet.Abrupt change beginning in 1888 was detected,revealing a transition from wet to dry conditions in south Tibet.Power spectrum analysis reveals significant cycles of 28-year,5.5-5.6-year and 3.3-year during the past 200 years.

  20. Dynamic cycles, ice streams and their impact on the extent, chronology and deglaciation of the British-Irish ice sheet

    Science.gov (United States)

    Hubbard, Alun; Bradwell, Tom; Golledge, Nicholas; Hall, Adrian; Patton, Henry; Sugden, David; Cooper, Rhys; Stoker, Martyn

    2009-04-01

    We present results from a suite of forward transient numerical modelling experiments of the British and Irish Ice Sheet (BIIS), consisting of Scottish, Welsh and Irish accumulation centres, spanning the last Glacial period from 38 to 10 ka BP. The 3D thermomechanical model employed uses higher-order physics to solve longitudinal (membrane) stresses and to reproduce grounding-line dynamics. Surface mass balance is derived using a distributed degree-day calculation based on a reference climatology from mean (1961-1990) precipitation and temperature patterns. The model is perturbed from this reference state by a scaled NGRIP oxygen isotope curve and the SPECMAP sea-level reconstruction. Isostatic response to ice loading is computed using an elastic lithosphere/relaxed asthenosphere scheme. A suite of 350 simulations were designed to explore the parameter space of model uncertainties and sensitivities, to yield a subset of experiments that showed close correspondence to offshore and onshore ice-directional indicators, broad BIIS chronology, and the relative sea-level record. Three of these simulations are described in further detail and indicate that the separate ice centres of the modelled BIIS complex are dynamically interdependent during the build up to maximum conditions, but remain largely independent throughout much of the simulation. The modelled BIIS is extremely dynamic, drained mainly by a number of transient but recurrent ice streams which dynamically switch and fluctuate in extent and intensity on a centennial time-scale. A series of binge/purge, advance/retreat, cycles are identified which correspond to alternating periods of relatively cold-based ice, (associated with a high aspect ratio and net growth), and wet-based ice with a lower aspect ratio, characterised by streaming. The timing and dynamics of these events are determined through a combination of basal thermomechanical switching spatially propagated and amplified through longitudinal coupling, but

  1. Age and dynamics of the Namib Sand Sea: A review of chronological evidence and possible landscape development models

    Science.gov (United States)

    Stone, A. E. C.

    2013-06-01

    The Namib Sand Sea constitutes a major physiographic feature of the Namib Desert on the west of Namibia, covering a 50-160 km wide region of the coast between Lüderitz and Walvis Bay. It is widely considered to be one of the oldest desert regions, with a Tertiary-aged fossil desert underlying the modern sand sea. The sand sea has been well studied, benefiting from the presence of the Gobabeb Training and Research Centre during the past 50 years. Whilst much is understood about its sediments and geomorphology, it is only recently that new chronological information, using cosmogenic-nuclide burial dating and optically stimulated luminescence dating have offered new insights, and this calls for an updated review of the age and landscape development of the sand sea. This assessment of the geomorphological and Quaternary dynamics of the region is complemented by developments in the description and analysis of sediment composition. New age control from cosmogenic dating indicates that the sand sea is in excess of a million years old. Initial data from luminescence dating yields depositional ages for dune sediments from three broad areas of the sand sea that include MIS 5, later in the Pleistocene around the Last Glacial Maximum and the Holocene, although it is not expected that these will be the only, or discrete age groupings. Detailed dating and application of ground penetrating radar in the far northern reaches reveals extensive dune migration and deposition during the Holocene. It is important to stress that the upper limit of luminescence dating here is about ˜200 ka (depending on the environmental dose rate of the site) and that migration and reworking of dunes resets the luminescence signal (so what is recorded is(are) the last phase(s) of preserved sediment accumulation). Whilst there are three potential sources of material for the Namib Sand Sea (reworked Tsondab Sandstone (TSS), material from the Great Escarpment derived by rivers and water and wind

  2. Sediment chronology in San Francisco Bay, California, defined by 210Pb, 234Th, 137Cs, and 239,340Pu

    Science.gov (United States)

    Fuller, C.C.; van Geen, Alexander; Baskaran, M.; Anima, R.

    1999-01-01

    Sediment chronologies based on radioisotope depth profiles were developed at two sites in the San Francisco Bay estuary to provide a framework for interpreting historical trends in organic compound and metal contaminant inputs. At Richardson Bay near the estuary mouth, sediments are highly mixed by biological and/or physical processes. Excess  penetration ranged from 2 to more than 10 cm at eight coring sites, yielding surface sediment mixing coefficients ranging from 12 to 170 cm2/year. At the site chosen for contaminant analyses, excess  activity was essentially constant over the upper 25 cm of the core with an exponential decrease below to the supported activity between 70 and 90 cm. Both  and  penetrated to 57-cm depth and have broad subsurface maxima between 33 and 41 cm. The best fit of the excess  profile to a steady state sediment accumulation and mixing model yielded an accumulation rate of 0.825 g/cm2/year (0.89 cm/year at sediment surface), surface mixing coefficient of 71 cm2/year, and 33-cm mixed zone with a half-Gaussian depth dependence parameter of 9 cm. Simulations of  and  profiles using these parameters successfully predicted the maximum depth of penetration and the depth of maximum  and  activity. Profiles of successive 1-year hypothetical contaminant pulses were generated using this parameter set to determine the age distribution of sediments at any depth horizon. Because of mixing, sediment particles with a wide range of deposition dates occur at each depth. A sediment chronology was derived from this age distribution to assign the minimum age of deposition and a date of maximum deposition to a depth horizon. The minimum age of sediments in a given horizon is used to estimate the date of first appearance of a contaminant from its maximum depth of penetration. The date of maximum deposition is used to estimate the peak year of input for a contaminant from the depth interval with the highest concentration of that contaminant

  3. Radiographic evaluation of third-molar development in relation to the chronological age of Turkish children in the southwest Eastern Anatolia region.

    Science.gov (United States)

    Karataş, Orhan H; Öztürk, Fırat; Dedeoğlu, Numan; Çolak, Cemil; Altun, Oğuzhan

    2013-10-10

    To study the chronological age of third-molar mineralisation of Turkish children from the southwest Eastern Anatolia region, the Demirjian staging method was used to determine the stage of the mineralisation of four third molars (18, 28, 38 and 48) and to compare third-molar development by sex and age with the results of previous studies. The study comprised 832 Turkish children from the southwest Eastern Anatolia region aged 6-16 years based on radiological evidence from digital orthopantomograms. The mean age of the 832 patients was 11.03±1.98 years, with 424 males (mean age, 10.97±1.97) and 408 females (mean age, 11.09±2.00). The orthopantomograms were scored by two observers. The Wilcoxon matched-pairs signed-rank test used to assess intra- and inter-observer assessment revealed strong agreement between both observers' measurements. Statistical analysis of the association between sex and age was performed with the Mann-Whitney U-test and the Wilcoxon test. Regression analysis was performed to obtain regression formulae for calculating the dental and the chronological age. The statistical analysis showed a strong correlation between age and third-molar development in males (R(2)=0.61) and females (R(2)=0.63). New equations (age=7.49+0.69, development stage (DS) 38+0.70, DS18) were derived for estimation of the chronological age. The results showed that there was no significant difference in mineralisation between 18 and 28 and 38 and 48 in males or females. For both sexes, the dental age was lower than the chronological age. Males reached the developmental stages earlier than females. In the whole population, the boys' and the girls' dental ages were 0.84 years and 0.16 years earlier, respectively, than their chronological ages. The use of third-molar teeth as a developmental marker is suitable, particularly when comparing the obtained standard deviation with other skeletal-age calculation techniques.

  4. Assessment of Telomere Length in Archived Formalin-Fixed, Paraffinized Human Tissue Is Confounded by Chronological Age and Storage Duration

    Science.gov (United States)

    2016-01-01

    Telomeres shorten with physiological aging but undergo substantial restoration during cancer immortalization. Increasingly, cancer studies utilize the archive of formalin-fixed, paraffin-embedded (FFPE) tissues in diagnostic pathology departments. Conceptually, such studies would be confounded by physiological telomere attrition and loss of DNA integrity from prolonged tissue storage. Our study aimed to investigate these two confounding factors. 145 FFPE tissues of surgically-resected, non-diseased appendixes were retrieved from our pathology archive, from years 2008 to 2014. Cases from 2013 to 2014 were categorized by patient chronological age (0–20 years, 21–40 years, 41–60 years, > 60 years). Telomere lengths of age categories were depicted by telomere/chromosome 2 centromere intensity ratio (TCR) revealed by quantitative fluorescence in situ hybridization. Material from individuals aged 0–20 years from years 2013/2014, 2011/2012, 2009/2010, and 2008 were compared for storage effect. Telomere integrity was assessed by telomere fluorescence intensity (TFI). Epithelial TCRs (mean ± SD) for the respective age groups were 4.84 ± 2.08, 3.64 ± 1.21, 2.03 ± 0.37, and 1.93 ± 0.45, whereas corresponding stromal TCRs were 5.16 ± 2.55, 3.84 ± 1.36, 2.49 ± 1.20, and 2.93 ± 1.24. A trend of inverse correlation with age in both epithelial and stromal tissues is supported by r = -0.69, p archived beyond 2 years are suboptimal for telomere analysis. PMID:27598341

  5. An improved chronology for the Lateglacial palaeoenvironmental record of Lake Haemelsee, Germany: challenges for independent site comparisons

    Science.gov (United States)

    Lane, Christine; Brauer, Achim; Ramsey Christopher, Bronk; Engels, Stefan; Haliuc, Aritina; Hoek, Wim; Hubay, Katalin; Jones, Gwydion; Sachse, Dirk; Staff, Richard; Turner, Falko; Wagner-Cremer, Frederike

    2016-04-01

    Exploring temporal and spatial variability of environmental response to climatic changes requires the comparison of widespread palaeoenvironmental sequences on their own, independently-derived, age models. High precision age-models can be constructed using statistical methods to combine absolute and relative age estimates measured using a range of techniques. Such an approach may help to highlight otherwise unrecognised uncertainties, where a single dating method has been applied in isolation. Radiocarbon dating, tephrochronology and varve counting have been combined within a Bayesian depositional model to build a chronology for a sediment sequence from Lake Haemelsee (Northern Germany) that continuously covers the entire Lateglacial and early Holocene. Each of the dating techniques used brought its own challenges. Radiocarbon dates provide the only absolute ages measured directly in the record, however a low macrofossil content led to small sample sizes and a limited number of low precision dates. A floating varved interval provided restricted but very precise relative dating for sediments covering the Allerød to Younger Dryas transition. Well-spaced, visible and crypto- tephra layers, including the widespread Laacher See , Vedde Ash, Askja-S and Saksunarvatn tephra layers, allow absolute ages for the tephra layers established in other locations to be imported into the Haemelsee sequence. These layers also provide multiple tie-lines that allow the Haemelsee sequences to be directly compared at particular moments in time, and within particular intervals, to other important Lateglacial archives. However, selecting the "best" published tephra ages to use in the Haemelsee age model is not simple and risks biasing comparison of the palaeoenvironmental record to fit one or another comparative archive. Here we investigate the use of multiple age models for the Haemelsee record, in order to retain an independent approach to investigating the environmental transitions of

  6. The chronology for the d18O record from Devils Hole, Nevada, extended into the Mid-Holocene

    Science.gov (United States)

    Landwehr, J.M.; Sharp, W.D.; Coplen, T.B.; Ludwig, K. R.; Winograd, I.J.

    2011-01-01

    This report presents the numeric values for the chronology of the paleoclimatically relevant mid-to-late Pleistocene record of the ratios of stable oxygen isotope (delta18O) in vein calcite from Devils Hole, Nev., which recently had been extended into the mid-Holocene. Dating was obtained using 230Th-234U-238U thermal ionization mass spectrometry. Devils Hole is a subaqueous cave of tectonic origin, which developed in the discharge zone of a regional aquifer in south-central Nevada. The primary groundwater recharge source area is the Spring Mountains, the highest mountain range in southern Nevada [altitude 3,630 meters (m)], approximately 80 kilometers to the east of the cavern. The walls of the open fault zone comprising the cave system are coated with dense vein calcite precipitated from the through-flowing groundwater. The calcite, up to 40 centimeters (cm) thick, contains a continuous record of the sequential variation of the composition of stable oxygen isotopes in the ground water over time. The vein calcite has also proven to be a suitable material for precise uranium-series dating via thermal ionization mass spectrometry utilizing the 230Th-234U-238U decay clock. Earlier work has presented data from the Devils Hole core DH-11, a 36-cm-long core of vein calcite recovered from a depth of about 30 m below the water table (about 45 m beneath the ground surface). The DH-11 core provided a continuous record of isotopic oxygen variation from 567,700 to 59,800 years before present. Recent work has extended this record up to 4,500 years before present, into the mid-Holocene epoch.

  7. Recalibration of the yellow Rhizocarpon growth curve in the Cordillera Blanca (Peru) and implications for LIA chronology

    Science.gov (United States)

    Jomelli, V.; Grancher, D.; Brunstein, D.; Solomina, O.

    2008-01-01

    A new lichen dating method and new moraine observations enabled us to improve the chronology of glacier advances in the Cordillera Blanca (Peru) during the Little Ice Age (LIA). Our results reveal that an early LIA glacial advance occurred around AD 1330 ± 29. However, a second major glacial advance at the beginning of the 17th century overlapped the earlier stage for most glaciers. Hence, this second glacial stage, dated from AD 1630 ± 27, is considered as the LIA maximum glacial advance in the Cordillera Blanca. During the 17th-18th centuries, at least three glacial advances were recorded synchronously for the different glaciers (AD 1670 ± 24, 1730 ± 21, and 1760 ± 19). The moraines corresponding to the two first stages are close to the one in 1630 suggesting a slow recession of about 18% in the total length of the glacier. From the LIA maximum extent to the beginning of the 20th century, the 24 glaciers have retreated a distance of about 1000 m, corresponding to a reduction of 30% in their length. This rate is comparable to that observed during the 20th century. Estimates of palaeo-Equilibrium Line Altitudes show an increase in altitude of about 100 m from the LIA maximum glacial extension at the beginning of the 17th century to the beginning of the 20th century. Because long time series are not available for precipitation and temperature, this glacial retreat is difficult to explain by past climate changes. However, there is a fair correspondence between changes in glacier length and the δ18O recorded in the Quelccaya ice core at a century timescale. Our current knowledge of tropical glaciers and isotope variations leads us to suggest that this common tropical signal reflects a change from a wet LIA to the drier conditions of today. Finally, a remarkable synchronicity is observed with glacial variations in Bolivia, suggesting a common regional climatic pattern during the LIA.

  8. Cross-cultural adaptation of the Maltreatment and Abuse Chronology of Exposure (MACE scale to Brazilian Portuguese

    Directory of Open Access Journals (Sweden)

    Bruno Kluwe-Schiavon

    2016-03-01

    Full Text Available Introduction : There is strong evidence to indicate that childhood maltreatment can negatively affect both physical and mental health and there is increasing interest in understanding the occurrence and consequences of such experiences. While several tools have been developed to retrospectively investigate childhood maltreatment experiences, most of them do not investigate the experience of witnessing family violence during childhood or bullying exposure. Moreover, the majority of scales do not identify when these experiences may have occurred, who was involved or the feelings evoked, such as helplessness or terror. The Maltreatment and Abuse Chronology of Exposure (MACE scale was developed to overcome these limitations. Objective : In view of the improvements over previous self-report instruments that this new tool offers and of the small number of self-report questionnaires for childhood maltreatment assessment available in Brazil, this study was conducted to conduct cross-cultural adaptation of the MACE scale for Brazilian Portuguese. Method : The following steps were performed: translation, back-translation, committee review for semantic and conceptual evaluation, and acceptability trial for equivalence. Results : Semantic and structural changes were made to the interview to adapt it for the Brazilian culture and all 75 of the items that comprise the longer version of MACE were translated. The results of the acceptability trial suggest that the items are comprehensible. Conclusion : The MACE scales may be useful tools for investigation of childhood maltreatment and make a valuable contribution to research in Brazil. Future studies should consider testing the availability and reliability of the three versions of the instrument translated into Brazilian Portuguese.

  9. Luminescence chronology of "Old Red Sand" in Jinjiang and its implications for optical dating of sediments in South China

    Institute of Scientific and Technical Information of China (English)

    ZHANG JiaFu; YUAN BaoYin; ZHOU LiPing

    2008-01-01

    A weathered deposit in South China is widespread on the coastal areas of Fujian and Guangdong provinces, China. This deposit consists of slightly cemented, medium- to fine-grained sands, and is characterized by its colors of red, brown red, light reddish brown or dark yellowish orange, and is usually called "Old Red Sand". The uncertainty in its formation age has been a major obstacle to the study of this type of deposit. In this paper, optically stimulated luminescence (OSL) techniques were used to date the "Old Red Sand" sediments from Jinjiang, Fujian Province, China. The effect of the geochemical behavior of uranium and thorium in sediment during chemical weathering on estimation of annual dose was investigated. The results show that the change in annual dose due to weathering poses a major problem for the optical,dating of such weathered sediments. The optical dating of these weathered deposits will produce erroneous ages if average annual dose during burial cannot be correctly estimated. For the profiles studied, the OSL dates obtained on samples from the upper part do not represent the burial age of the samples. It is highly likely that they are underestimated due mainly to the accumulated radioactive elements as a result of chemical weathering. It is concluded that changes in annual dose due to chemical weathering must be considered when dating similar sediments in South China. With a detailed analysis of the OSL dating results, the chronology of the marine terraces in this area was suggested. The lowest terrace was formed at -3.5 ka and the second terrace was dated to -74 ka. The age of the highest terrace may not be established accurately, but is inferred to be older than the apparent OSL date of ~77 ka and so is the Paleolithic artifacts from it.

  10. Marek's disease virus infection in the eye: chronological study of the lesions, virus replication, and vaccine-induced protection.

    Science.gov (United States)

    Pandiri, Arun K R; Cortes, Aneg L; Lee, Lucy F; Gimeno, I M

    2008-12-01

    Marek's disease virus (MDV) infection in the eye was studied chronologically after inoculating 1-day-old chickens with a very virulent MDV strain, Md5. The ocular lesions could be classified as early lesions (6-11 days postinoculation [dpi]) and late lesions (26 and 56 dpi), based upon the location and severity of the lesions. The early lesions involved iris, ciliary body, and choroid layer, and were characterized by endothelial cell hypertrophy, vasculitis, and infiltration of lymphocytes (mainly CD8+), plasma cells, macrophages, and heterophils. Expression of early MDV-antigen pp38 in the cells infiltrating choroid layer was detected as early as 11 dpi. Late lesions consisted of severe lymphohistiocytic uveitis, keratitis, pectenitis, vitreitis, retinitis, and segmental to diffuse retinal necrosis. Cell infiltration included macrophages, granulocytes, plasma cells, and both CD4+ and CD8+ cells of various sizes. Expression of early MDV-antigen pp38 was readily found within the retina, uveal tract, and corneal epithelium. No expression of late-antigen gB or oncoprotein meq was detected in any of the eyes examined. A second experiment was conducted to study the effect of vaccination on the development of ocular lesions. Both HVT and CVI988 were able to protect against the development of early ocular lesions in chickens infected with very virulent plus strain MDV 648A. However, only CVI988 conferred complete protection against the development of late ocular lesions. HVT conferred partial protection, as it reduced the frequency and severity of the late ocular lesions. These results enhance our understanding of the nature and pattern of MDV infection in the eye.

  11. Chronology of prescribing error during the hospital stay and prediction of pharmacist's alerts overriding: a prospective analysis

    Directory of Open Access Journals (Sweden)

    Bruni Vanida

    2010-01-01

    Full Text Available Abstract Background Drug prescribing errors are frequent in the hospital setting and pharmacists play an important role in detection of these errors. The objectives of this study are (1 to describe the drug prescribing errors rate during the patient's stay, (2 to find which characteristics for a prescribing error are the most predictive of their reproduction the next day despite pharmacist's alert (i.e. override the alert. Methods We prospectively collected all medication order lines and prescribing errors during 18 days in 7 medical wards' using computerized physician order entry. We described and modelled the errors rate according to the chronology of hospital stay. We performed a classification and regression tree analysis to find which characteristics of alerts were predictive of their overriding (i.e. prescribing error repeated. Results 12 533 order lines were reviewed, 117 errors (errors rate 0.9% were observed and 51% of these errors occurred on the first day of the hospital stay. The risk of a prescribing error decreased over time. 52% of the alerts were overridden (i.e error uncorrected by prescribers on the following day. Drug omissions were the most frequently taken into account by prescribers. The classification and regression tree analysis showed that overriding pharmacist's alerts is first related to the ward of the prescriber and then to either Anatomical Therapeutic Chemical class of the drug or the type of error. Conclusions Since 51% of prescribing errors occurred on the first day of stay, pharmacist should concentrate his analysis of drug prescriptions on this day. The difference of overriding behavior between wards and according drug Anatomical Therapeutic Chemical class or type of error could also guide the validation tasks and programming of electronic alerts.

  12. Chronological overlap between humans and megafauna in Sahul (Pleistocene Australia New Guinea): A review of the evidence

    Science.gov (United States)

    Field, Judith; Fillios, Melanie; Wroe, Stephen

    2008-08-01

    Over 60 faunal species disappeared from the Australian continent during the Middle-Late Pleistocene. Most of these animals were large to gigantic marsupials, birds and reptiles. A terminal extinction date of 46.4 kyr has been proposed for the megafauna, with all sites containing younger fossil megafauna dismissed by some researchers because of questions over stratigraphic integrity or chronologies. The timing of the extinctions is argued to be broadly coincident with estimates of first colonization of the continent by modern humans, and explanatory extinction models involving humans have subsequently gained currency. However there is considerable evidence to suggest that in some parts of the continent, people and some species of megafauna may have co-existed well beyond 46.4 kyr. In other places, such as Tasmania and the north of the continent, there is no known record of a human-megafauna temporal overlap. A review of the available evidence indicates that only 13 species of megafauna were extant on human arrival in Australia. The archaeology of this period indicates that rather than a focus on big game hunting or 'firestick farming', it was characterized by regional variability in subsistence strategies consistent with the range of environmental zones. At the present time there is no substantive argument for a terminal extinction date of 46.4 kyr, the current evidence indicating that there is no specific time period that correlates to any single mass extinction event. On the basis of available evidence arguments for either human or climatic causation are entirely circumstantial and implicitly require acceptance of many unproven assumptions. Claims to have eliminated climate as a primary driver are premature and the recent focus on delivering 'proof' of human causation in Pleistocene faunal extinctions diverts attention from achieving a better understanding of the differential impacts of climate change and short term climatic flux in a land of environmental

  13. Towards an Accurate and Precise Chronology for the Colonization of Australia: The Example of Riwi, Kimberley, Western Australia

    Science.gov (United States)

    Balme, Jane; O’Connor, Sue; Whitau, Rose

    2016-01-01

    An extensive series of 44 radiocarbon (14C) and 37 optically stimulated luminescence (OSL) ages have been obtained from the site of Riwi, south central Kimberley (NW Australia). As one of the earliest known Pleistocene sites in Australia, with archaeologically sterile sediment beneath deposits containing occupation, the chronology of the site is important in renewed debates surrounding the colonization of Sahul. Charcoal is preserved throughout the sequence and within multiple discrete hearth features. Prior to 14C dating, charcoal has been pretreated with both acid-base-acid (ABA) and acid base oxidation-stepped combustion (ABOx-SC) methods at multiple laboratories. Ages are consistent between laboratories and also between the two pretreatment methods, suggesting that contamination is easily removed from charcoal at Riwi and the Pleistocene ages are likely to be accurate. Whilst some charcoal samples recovered from outside hearth features are identified as outliers within a Bayesian model, all ages on charcoal within hearth features are consistent with stratigraphy. OSL dating has been undertaken using single quartz grains from the sandy matrix. The majority of samples show De distributions that are well-bleached but that also include evidence for mixing as a result of post-depositional bioturbation of the sediment. The results of the two techniques are compared and evaluated within a Bayesian model. Consistency between the two methods is good, and we demonstrate human occupation at this site from 46.4–44.6 cal kBP (95.4% probability range). Importantly, the lowest archaeological horizon at Riwi is underlain by sterile sediments which have been dated by OSL making it possible to demonstrate the absence of human occupation for between 0.9–5.2 ka (68.2% probability range) prior to occupation. PMID:27655174

  14. The 'Maltreatment and Abuse Chronology of Exposure' (MACE) scale for the retrospective assessment of abuse and neglect during development.

    Science.gov (United States)

    Teicher, Martin H; Parigger, Angelika

    2015-01-01

    There is increasing interest in childhood maltreatment as a potent stimulus that may alter trajectories of brain development, induce epigenetic modifications and enhance risk for medical and psychiatric disorders. Although a number of useful scales exist for retrospective assessment of abuse and neglect they have significant limitations. Moreover, they fail to provide detailed information on timing of exposure, which is critical for delineation of sensitive periods. The Maltreatment and Abuse Chronology of Exposure (MACE) scale was developed in a sample of 1051 participants using item response theory to gauge severity of exposure to ten types of maltreatment (emotional neglect, non-verbal emotional abuse, parental physical maltreatment, parental verbal abuse, peer emotional abuse, peer physical bullying, physical neglect, sexual abuse, witnessing interparental violence and witnessing violence to siblings) during each year of childhood. Items included in the subscales had acceptable psychometric properties based on infit and outfit mean square statistics, and each subscale passed Andersen's Likelihood ratio test. The MACE provides an overall severity score and multiplicity score (number of types of maltreatment experienced) with excellent test-retest reliability. Each type of maltreatment showed good reliability as did severity of exposure across each year of childhood. MACE Severity correlated 0.738 with Childhood Trauma Questionnaire (CTQ) score and MACE Multiplicity correlated 0.698 with the Adverse Childhood Experiences scale (ACE). However, MACE accounted for 2.00- and 2.07-fold more of the variance, on average, in psychiatric symptom ratings than CTQ or ACE, respectively, based on variance decomposition. Different types of maltreatment had distinct and often unique developmental patterns. The 52-item MACE, a simpler Maltreatment Abuse and Exposure Scale (MAES) that only assesses overall exposure and the original test instrument (MACE-X) with several additional

  15. Assessment of Telomere Length in Archived Formalin-Fixed, Paraffinized Human Tissue Is Confounded by Chronological Age and Storage Duration.

    Science.gov (United States)

    Kong, Po-Lian; Looi, Lai-Meng; Lau, Tze-Pheng; Cheah, Phaik-Leng

    2016-01-01

    Telomeres shorten with physiological aging but undergo substantial restoration during cancer immortalization. Increasingly, cancer studies utilize the archive of formalin-fixed, paraffin-embedded (FFPE) tissues in diagnostic pathology departments. Conceptually, such studies would be confounded by physiological telomere attrition and loss of DNA integrity from prolonged tissue storage. Our study aimed to investigate these two confounding factors. 145 FFPE tissues of surgically-resected, non-diseased appendixes were retrieved from our pathology archive, from years 2008 to 2014. Cases from 2013 to 2014 were categorized by patient chronological age (0-20 years, 21-40 years, 41-60 years, > 60 years). Telomere lengths of age categories were depicted by telomere/chromosome 2 centromere intensity ratio (TCR) revealed by quantitative fluorescence in situ hybridization. Material from individuals aged 0-20 years from years 2013/2014, 2011/2012, 2009/2010, and 2008 were compared for storage effect. Telomere integrity was assessed by telomere fluorescence intensity (TFI). Epithelial TCRs (mean ± SD) for the respective age groups were 4.84 ± 2.08, 3.64 ± 1.21, 2.03 ± 0.37, and 1.93 ± 0.45, whereas corresponding stromal TCRs were 5.16 ± 2.55, 3.84 ± 1.36, 2.49 ± 1.20, and 2.93 ± 1.24. A trend of inverse correlation with age in both epithelial and stromal tissues is supported by r = -0.69, p tissues, and suggest that an age-based reference can be established for telomere studies on FFPE tissues. We also showed that FFPE tissues archived beyond 2 years are suboptimal for telomere analysis. PMID:27598341

  16. Constraints on bed scale fracture chronology with a FEM mechanical model of folding: The case of Split Mountain (Utah, USA)

    Science.gov (United States)

    Sassi, W.; Guiton, M. L. E.; Leroy, Y. M.; Daniel, J.-M.; Callot, J.-P.

    2012-11-01

    A technique is presented for improving the structural analysis of natural fractures development in large scale fold structures. A 3D restoration of a fold provides the external displacement loading conditions to solve, by the finite element method, the forward mechanical problem of an idealized rock material with a stress-strain relationship based on the activation of pervasive fracture sets. In this elasto-plasticity constitutive law, any activated fracture set contributes to the total plastic strain by either an opening or a sliding mode of rock failure. Inherited versus syn-folding fracture sets development can be studied using this mechanical model. The workflow of this methodology was applied to the Weber sandstone formation deformed by forced folding at Split Mountain Anticline, Utah for which the different fracture sets were created and developed successively during the Sevier and the syn-folding Laramide orogenic phases. The field observations at the top stratigraphic surface of the Weber sandstone lead to classify the fracture sets into a pre-fold WNW-ESE fracture set, and a NE-SW fracture set post-dating the former. The development and relative chronology of the fracture sets are discussed based on the geomechanical modeling results. Starting with a 3D restoration of the Split Mountain Anticline, three fold-fracture development models were generated, alternately assuming that the WNW-ESE fracture set is either present or absent prior to folding process. Depending on the initial fracture configuration, the calculated fracture patterns are markedly different, showing that assuming a WNW-ESE joint set to predate the fold best correlates with field observations. This study is a first step addressing the complex problem of identification of fold-related fracturing events using an elementary concept of rock mechanics. When tight to complementary field observations, including petrography, diagenesis and burial history, the approach can be used to better

  17. The 'Maltreatment and Abuse Chronology of Exposure' (MACE scale for the retrospective assessment of abuse and neglect during development.

    Directory of Open Access Journals (Sweden)

    Martin H Teicher

    Full Text Available There is increasing interest in childhood maltreatment as a potent stimulus that may alter trajectories of brain development, induce epigenetic modifications and enhance risk for medical and psychiatric disorders. Although a number of useful scales exist for retrospective assessment of abuse and neglect they have significant limitations. Moreover, they fail to provide detailed information on timing of exposure, which is critical for delineation of sensitive periods. The Maltreatment and Abuse Chronology of Exposure (MACE scale was developed in a sample of 1051 participants using item response theory to gauge severity of exposure to ten types of maltreatment (emotional neglect, non-verbal emotional abuse, parental physical maltreatment, parental verbal abuse, peer emotional abuse, peer physical bullying, physical neglect, sexual abuse, witnessing interparental violence and witnessing violence to siblings during each year of childhood. Items included in the subscales had acceptable psychometric properties based on infit and outfit mean square statistics, and each subscale passed Andersen's Likelihood ratio test. The MACE provides an overall severity score and multiplicity score (number of types of maltreatment experienced with excellent test-retest reliability. Each type of maltreatment showed good reliability as did severity of exposure across each year of childhood. MACE Severity correlated 0.738 with Childhood Trauma Questionnaire (CTQ score and MACE Multiplicity correlated 0.698 with the Adverse Childhood Experiences scale (ACE. However, MACE accounted for 2.00- and 2.07-fold more of the variance, on average, in psychiatric symptom ratings than CTQ or ACE, respectively, based on variance decomposition. Different types of maltreatment had distinct and often unique developmental patterns. The 52-item MACE, a simpler Maltreatment Abuse and Exposure Scale (MAES that only assesses overall exposure and the original test instrument (MACE-X with

  18. The 'Maltreatment and Abuse Chronology of Exposure' (MACE) scale for the retrospective assessment of abuse and neglect during development.

    Science.gov (United States)

    Teicher, Martin H; Parigger, Angelika

    2015-01-01

    There is increasing interest in childhood maltreatment as a potent stimulus that may alter trajectories of brain development, induce epigenetic modifications and enhance risk for medical and psychiatric disorders. Although a number of useful scales exist for retrospective assessment of abuse and neglect they have significant limitations. Moreover, they fail to provide detailed information on timing of exposure, which is critical for delineation of sensitive periods. The Maltreatment and Abuse Chronology of Exposure (MACE) scale was developed in a sample of 1051 participants using item response theory to gauge severity of exposure to ten types of maltreatment (emotional neglect, non-verbal emotional abuse, parental physical maltreatment, parental verbal abuse, peer emotional abuse, peer physical bullying, physical neglect, sexual abuse, witnessing interparental violence and witnessing violence to siblings) during each year of childhood. Items included in the subscales had acceptable psychometric properties based on infit and outfit mean square statistics, and each subscale passed Andersen's Likelihood ratio test. The MACE provides an overall severity score and multiplicity score (number of types of maltreatment experienced) with excellent test-retest reliability. Each type of maltreatment showed good reliability as did severity of exposure across each year of childhood. MACE Severity correlated 0.738 with Childhood Trauma Questionnaire (CTQ) score and MACE Multiplicity correlated 0.698 with the Adverse Childhood Experiences scale (ACE). However, MACE accounted for 2.00- and 2.07-fold more of the variance, on average, in psychiatric symptom ratings than CTQ or ACE, respectively, based on variance decomposition. Different types of maltreatment had distinct and often unique developmental patterns. The 52-item MACE, a simpler Maltreatment Abuse and Exposure Scale (MAES) that only assesses overall exposure and the original test instrument (MACE-X) with several additional

  19. Site formation and chronology of the new Paleolithic site Sima de Las Palomas de Teba, southern Spain

    Science.gov (United States)

    Kehl, Martin; Burow, Christoph; Cantalejo, Pedro; Domínguez-Bella, Salvador; Durán, Juan José; Henselowsky, Felix; Klasen, Nicole; Linstädter, Jörg; Medianero, Javier; Pastoors, Andreas; Ramos, José; Reicherter, Klaus; Schmidt, Christoph; Weniger, Gerd-Christian

    2016-03-01

    The newly identified Paleolithic site Sima de Las Palomas de Teba hosts an almost seven-m-thick sediment profile investigated here to elucidate the rock shelter's chronostratigraphy and formation processes. At its base, the sediment sequence contains rich archeological deposits recording intensive occupation by Neanderthals. Luminescence provides a terminus ante quem of 39.4 ± 2.6 ka or 44.9 ± 4.1 ka (OSL) and 51.4 ± 8.4 ka (TL). This occupation ended with a rockfall event followed by accumulation of archeologically sterile sediments. These were covered by sediments containing few Middle Paleolithic artifacts, which either indicate ephemeral occupation by Neanderthals or reworking as suggested by micromorphological features. Above this unit, scattered lithic artifacts of undiagnostic character may represent undefined Paleolithic occupations. Sediment burial ages between about 23.0 ± 1.5 ka (OSL) and 40.5 ± 3.4 ka (pIRIR) provide an Upper Paleolithic chronology for sediments deposited above the rockfall. Finally, a dung-bearing Holocene layer in the uppermost part of the sequence contains a fragment of a human mandible dated to 4032 ± 39 14C yr BP. Overall, the sequence represents an important new site for studying the end of Neanderthal occupation in southern Spain. Supplementary Figure S2: Preheat-plateau and dose-recovery test results for OSL on fine-grained quartz of samples CP7. Aliquots for the dose-recovery test were administered a dose of 40 Gy after removing the natural signal by blue stimulation for 150 s at 125°C and 80% optical power. Supplementary Figure S3: Dependence of equivalent dose on prior IR stimulation temperature for samples CP1, CP3 and CP7. For each sample and pIRIR protocol six aliquots were used while increasing the first IR stimulation temperature in steps of 30°C from 50°C to 140°C and to 180°C. Data are normalized to the pIRIR De obtained with a first IR stimulation at 50°C. Supplementary Figure S4: Regenerative TL glow

  20. "EDML1": a chronology for the EPICA deep ice core from Dronning Maud Land, Antarctica, over the last 150 000 years

    Directory of Open Access Journals (Sweden)

    U. Ruth

    2007-03-01

    Full Text Available A chronology called EDML1 has been developed for the EPICA ice core from Dronning Maud Land (EDML. EDML1 is closely interlinked with EDC3, the new chronology for the EPICA ice core from Dome-C (EDC through a stratigraphic match between EDML and EDC that consists of 322 volcanic match points over the last 128 ka. The EDC3 chronology comprises a glaciological model at EDC, which is constrained and later selectively tuned using primary dating information from EDC as well as from EDML, the latter being transferred using the tight stratigraphic link between the two cores. Finally, EDML1 was built by exporting EDC3 to EDML. For ages younger than 41 ka BP EDML1/EDC3 is based on dated volcanic events and on a match to the Greenlandic GICC05 time scale via 10Be and methane. The internal consistency between EDML1 and EDC3 is estimated to be typically ~6 years and always less than 450 years over the last 128 ka (always less than 130 years over the last 60 ka, which reflects an unprecedented synchrony of time scales. EDML1 ends at 150 ka BP (2417 m depth because the match between EDML and EDC becomes ambiguous further down. This hints to a complex ice flow history for the deepest 350 m of the EDML ice core, which amongst other reasons may be caused by spatial variations of the geothermal heat flux.

  1. The WAIS-Divide deep ice core WD2014 chronology – Part 2: Methane synchronization (68–31 ka BP and the gas age-ice age difference

    Directory of Open Access Journals (Sweden)

    C. Buizert

    2014-08-01

    Full Text Available The West Antarctic Ice Sheet (WAIS-Divide ice core (WAIS-D is a newly drilled, high-accumulation deep ice core that provides Antarctic climate records of the past ∼68 ka at unprecedented temporal resolution. The upper 2850 m (back to 31.2 ka BP have been dated using annual-layer counting. Here we present a chronology for the deep part of the core (67.8–31.2 ka BP, which is based on stratigraphic matching to annual-layer-counted Greenland ice cores using globally well-mixed atmospheric methane. We calculate the WAIS-D gas age-ice age difference (Δage using a combination of firn densification modeling, ice flow modeling, and a dataset of δ15N-N2, a proxy for past firn column thickness. The largest Δage at WAIS-D occurs during the last glacial maximum, and is 525 ± 100 years. Internally consistent solutions can only be found when assuming little-to-no influence of impurity content on densification rates, contrary to a recently proposed hypothesis. We synchronize the WAIS-D chronology to a linearly scaled version of the layer-counted Greenland Ice Core Chronology (GICC05, which brings the age of Dansgaard-Oeschger (DO events into agreement with the U/Th absolutely dated Hulu speleothem record. The small Δage at WAIS-D provides valuable opportunities to investigate the timing of atmospheric greenhouse gas variations relative to Antarctic climate, as well as the interhemispheric phasing of the bipolar "seesaw".

  2. Integration of paleoseismic data from multiple sites to develop an objective earthquake chronology: Application to the Weber segment of the Wasatch fault zone, Utah

    Science.gov (United States)

    DuRoss, Christopher B.; Personius, Stephen F.; Crone, Anthony J.; Olig, Susan S.; Lund, William R.

    2011-01-01

    We present a method to evaluate and integrate paleoseismic data from multiple sites into a single, objective measure of earthquake timing and recurrence on discrete segments of active faults. We apply this method to the Weber segment (WS) of the Wasatch fault zone using data from four fault-trench studies completed between 1981 and 2009. After systematically reevaluating the stratigraphic and chronologic data from each trench site, we constructed time-stratigraphic OxCal models that yield site probability density functions (PDFs) of the times of individual earthquakes. We next qualitatively correlated the site PDFs into a segment-wide earthquake chronology, which is supported by overlapping site PDFs, large per-event displacements, and prominent segment boundaries. For each segment-wide earthquake, we computed the product of the site PDF probabilities in common time bins, which emphasizes the overlap in the site earthquake times, and gives more weight to the narrowest, best-defined PDFs. The product method yields smaller earthquake-timing uncertainties compared to taking the mean of the site PDFs, but is best suited to earthquakes constrained by broad, overlapping site PDFs. We calculated segment-wide earthquake recurrence intervals and uncertainties using a Monte Carlo model. Five surface-faulting earthquakes occurred on the WS at about 5.9, 4.5, 3.1, 1.1, and 0.6 ka. With the exception of the 1.1-ka event, we used the product method to define the earthquake times. The revised WS chronology yields a mean recurrence interval of 1.3 kyr (0.7–1.9-kyr estimated two-sigma [2δ] range based on interevent recurrence). These data help clarify the paleoearthquake history of the WS, including the important question of the timing and rupture extent of the most recent earthquake, and are essential to the improvement of earthquake-probability assessments for the Wasatch Front region.

  3. Climate Signals from Tree Ring Chronologies of the Upper and Lower Treelines in the Dulan Region of the Northeastern Qinghai-Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The radial growth of trees in mountainous areas is subject to environmental conditions associated with changes in elevation. To assess the sensitivity of tree-ring growth to climate variation over a wide range of elevations,we compared the chronological characteristics of Sabina przewalskii Kom. and their relationships with climatic variables at the upper and lower treelines in the Dulan region of the northeastern Qinghai-Tibetan Plateau. It was found that the radial growth in this region was controlled primarily by precipitation in late spring and early summer (from May to June). In addition, a higher temperature from April to June could intensify drought stress and lead to narrow tree rings. The significant similarity in climate-tree growth relationships at both the upper and lower treelines indicated that tree rings of S. przewalskii in this region are able to provide common regional climate information. However, the chronologies at the lower forest limits showed a higher standard deviation and more significant correlations with climatic factors, suggesting that the radial growth there was more significantly influenced by climate variation. The first principal component of the four chronologies showed a common growth response to local climate. The second principal component showed a contrasting growth response between different sampling sites. The third principal component revealed different growth patterns in response to altitudinal variation. Further analysis indicated that the precipitation in late spring and early summer controlled the growth of S. przewalskii on a regional scale and that other factors, such as microenvironment at the sampling sites, also affected the strength of the climatic response of tree growth.

  4. Index to Nuclear Safety: a technical progress review by chronology, permuted title, and author, Volume 18 (1) through Volume 22 (6)

    Energy Technology Data Exchange (ETDEWEB)

    Cottrell, W.B.; Passiakos, M.

    1982-06-01

    This index to Nuclear Safety covers articles published in Nuclear Safety, Volume 18, Number 1 (January-February 1977) through Volume 22, Number 6 (November-December 1981). The index is divided into three section: a chronological list of articles (including abstracts), a permuted-title (KWIC) index, and an author index. Nuclear Safety, a bimonthly technical progress review prepared by the Nuclear Safety Information Center, covers all safety aspects of nuclear power reactors and associated facilities. Over 300 technical articles published in Nuclear Safety in the last 5 years are listed in this index.

  5. Home-based Early Intervention on Auditory and Speech Development in Mandarin-speaking Deaf Infants and Toddlers with Chronological Aged 7-24 Months

    Institute of Scientific and Technical Information of China (English)

    Ying Yang; Yue-Hui Liu; Ming-Fu Fu; Chun-Lin Li; Li-Yan Wang; Qi Wang; Xi-Bin Sun

    2015-01-01

    Background:Early auditory and speech development in home-based early intervention of infants and toddlers with hearing loss younger than 2 years are still spare in China.This study aimed to observe the development of auditory and speech in deaf infants and toddlers who were fitted with hearing aids and/or received cochlear implantation between the chronological ages of 7-24 months,and analyze the effect of chronological age and recovery time on auditory and speech development in the course of home-based early intervention.Methods:This longitudinal study included 55 hearing impaired children with severe and profound binaural deafness,who were divided into Group A (7-12 months),Group B (13-18 months) and Group C (19-24 months) based on the chronological age.Categories auditory performance (CAP) and speech intelligibility rating scale (SIR) were used to evaluate auditory and speech development at baseline and 3,6,9,12,18,and 24 months of habilitation.Descriptive statistics were used to describe demographic features and were analyzed by repeated measures analysis of variance.Results:With 24 months of hearing intervention,78% of the patients were able to understand common phrases and conversation without lip-reading,96% of the patients were intelligible to a listener.In three groups,children showed the rapid growth of trend features in each period of habilitation.CAP and SIR scores have developed rapidly within 24 months after fitted auxiliary device in Group A,which performed much better auditory and speech abilities than Group B (P < 0.05) and Group C (P < 0.05).Group B achieved better results than Group C,whereas no significant differences were observed between Group B and Group C (P > 0.05).Conclusions:The data suggested the early hearing intervention and home-based habilitation benefit auditory and speech development.Chronological age and recovery time may be major factors for aural verbal outcomes in hearing impaired children.The development of auditory

  6. Index to Nuclear Safety. A technical progress review by chronology, permuted title, and author. Vol 11, No. 1 through Vol. 16, No. 6

    International Nuclear Information System (INIS)

    This index to Nuclear Safety covers articles in Nuclear Safety Vol. 11, No. 1 (Jan.-Feb. 1970) through Vol. 16, No. 6 (Nov.-Dec. 1975). Included in the index is a chronological list of articles (including abstract) followed by both a KWIC index and an Author Index. Nuclear Safety is a bimonthly technical progress review prepared by the Nuclear Safety Information Center and covers all safety aspects of nuclear power reactors and associated facilities. The index lists over 300 technical articles in the last six years of publication

  7. A new luminescence dating chronology for the Rhafas cave site (NE Morocco): Insights into Palaeolithic human cultural change under varying palaeoenvironmental conditions in the Maghreb

    Science.gov (United States)

    Dörschner, Nina; Fitzsimmons, Kathryn E.; Ditchfield, Peter; McLaren, Sue J.; Steele, Teresa E.; Zielhofer, Christoph; McPherron, Shannon P.; Bouzouggar, Abdeljalil; Hublin, Jean-Jacques

    2016-04-01

    Archaeological sites in northern Africa provide a rich record that is of increasing importance for current debates relating to the origins of modern human behaviour and to Out of Africa human dispersal events. Particular interest is placed on the cultural transition between the North African Middle Stone Age (MSA) and Late Stone Age (LSA), and the need for accurately defined chronologies, however the timing and nature of Palaeolithic human behaviour and dispersal across north-western Africa (the Maghreb) and potential correlation with environmental conditions remain poorly understood. The inland cave site of Rhafas (Morocco) preserves a long stratified sequence providing valuable chronological information about cultural changes in the Maghreb spanning the North African MSA through to the Neolithic. In this study, we apply optically stimulated luminescence (OSL) dating on sand-sized quartz grains to the cave deposits of Rhafas as well as to a section on the terrace in front of the cave entrance. Single grain OSL dating reliably constrains the timing of technocomplexes beyond the limits of radiocarbon by directly dating sediment associated with archaeological traces. We combine OSL dating with multi-proxy geological investigations (XRF, grain size analyses, stable isotopes, thin sections) to investigate site formation processes and reconstruct palaeoenvironmental conditions during human occupation phases at Rhafas. Our results indicate that the occupation of the site started at least in MIS 6 during a phase of relatively arid environmental conditions. Climatic amelioration after c.140 ka is associated with a change in sediment geochemistry at the site, most likely linked to a change in sediment source due to shifting wind directions. Tanged pieces - typical for the classical Aterian technocomplex - start to occur in the archaeological sequence in MIS 5, consistent with previously published chronological data from the Maghreb. From 55 ka, climatic conditions were

  8. Chronology of glaciations in the Cantabrian Mountains (NW Iberia) during the Last Glacial Cycle based on in situ-produced 10Be

    Science.gov (United States)

    Rodríguez-Rodríguez, Laura; Jiménez-Sánchez, Montserrat; Domínguez-Cuesta, María José; Rinterknecht, Vincent; Pallàs, Raimon; Bourlès, Didier

    2016-04-01

    The mountain ranges of the Iberian Peninsula preserve a valuable record of past glaciations that may help reconstruct past atmospheric circulation patterns in response to cooling events in the North Atlantic Ocean. Available chronologies for the glacial record of the Cantabrian Mountains, which are mainly based on radiocarbon and luminescence dating of glacial-related sediments, suggest that glaciers recorded their Glacial Maximum (GM) during MIS 3 and experienced a later Last Glacial Maximum (LGM) advance. This LGM extent is not established yet, preventing a fair correlation with available Cosmic Ray Exposure (CRE) based chronologies for the glacial record of the Pyrenees and the Sistema Central. We present a glacial reconstruction and a 10Be CRE chronology for the Porma valley, in the southern slope of the central Cantabrian Mountains. Glacial evidence at the lowest altitudes correspond to erratic boulders and composite moraines whose minimum 10Be CRE age of 113.9 ± 7.1 ka suggests that glaciers were at their maximum extent during MIS 5d, most likely in response to the minima in summertime insolation of the Last Glacial Cycle. Recessional moraines preserved within the glacial maximum limits allow the assessment of subsequent glacier advances or stagnations. The most remarkable advance took place prior to 55.7 ± 4.0 ka (probably at the end of MIS 4), consistently with minimum radiocarbon ages previously reported for lacustrine glacial-related deposits in the Cantabrian Mountains. A limited number of 10Be CRE ages from a composite moraine suggest a possible advance of the Porma glacier coeval with the global LGM; the glacier front attributed to the LGM would be placed within the margins of the previous GM like in the western Pyrenees. Erratic boulders perched on an ice-moulded bedrock surface provided a mean 10Be CRE age of 17.7 ± 1.0 ka, suggesting that part of the recessional moraine sequence corresponds to minor advances or stagnations of the glacier fronts

  9. Index to Nuclear Safety: a technical progress review by chronology, permuted title, and author. Vol. 11(1)--Vol. 18(6)

    Energy Technology Data Exchange (ETDEWEB)

    Cottrell, W.B.; Klein, A.

    1978-04-11

    This index to Nuclear Safety covers articles published in Nuclear Safety, Vol. 11, No. 1 (January-February 1970), through Vol. 18, No. 6 (November-December 1977). It is divided into three sections: a chronological list of articles (including abstracts) followed by a permuted-title (KWIC) index and an author index. Nuclear Safety, a bimonthly technical progress review prepared by the Nuclear Safety Information Center (NSIC), covers all safety aspects of nuclear power reactors and associated facilities. Over 450 technical articles published in Nuclear Safety in the last eight years are listed in this index.

  10. The Rodì-Tindari-Vallelunga culture in Sicily: origins, diffusion and chronology in the light of recent studies. Part 1

    Directory of Open Access Journals (Sweden)

    Viviana Ardesia

    2014-12-01

    Full Text Available The present study deals with the history of studies and the archaeological evidence currently known of the facies of Rodì Tindari Vallelunga (RTV , analyzying the peculiarities of settlements, burials and ceramics compared with the contemporary cultures of Castelluccio and Capo Graziano. It follows a proposal for the classification of RTV pottery production, based on the evidence from Mursia (Pantelleria and from others sites attributed to this facies. Finally hypotheses on the origin, spread and chronology of the RTV facies are proposed.

  11. (UnResolved contradictions in the Late Pleistocene glacial chronology of the Southern Carpathians - new samples and recalculated cosmogenic radionuclide age estimates

    Directory of Open Access Journals (Sweden)

    Zsófia RUSZKICZAY-RÜDIGER

    2014-11-01

    Full Text Available Application of cosmogenic nuclides in the study of Quaternary glaciations has increased rapidly during the last decade owing to the previous absence of direct dating methods of glacial landforms and sediments. Although several hundred publications have already been released on exposure age dating of glacial landforms worldwide, very few studies targeted the Carpathians so far (Kuhlemann et al, 2013a; Makos et al., 2014; Reuther et al, 2004, 2007; Rinterknecht et al. 2012.There are many unresolved or contradictory issues regarding the glacial chronology of the Romanian Carpathians. Recently, some attempts have been made to develop an improved temporal framework for the glaciations of the region using cosmogenic 10Be dating (Reuther et al. 2004, 2007, Kuhlemann et al. 2013a. However, these studies made the picture even more confusing because the local last glacial maximum, for instance, apparently occurred in asynchronous timing compared to each other and also to other dated glacial events in Europe (Hughes et al, 2013.This situation is even more interesting if we take into account that the local glacial maximum tends to agree with the global LGM derived from the Eastern Balkans (Kuhlemann et al. 2013b, while the penultimate glaciation seems to significantly overtake the LGM advance over the Western Balkans (Hughes et al. 2011.The primary candidate reasons to resolve these discrepancies are methodological, e.g. insufficient number of samples (one sample/landform ignoring geological scatter of the data and the application of different half-lives, production rates and scaling schemes during the calculation of exposure ages. Systematic methodological uncertainties in computing exposure ages from measured nuclide concentrations have a significant impact on the conclusions concerning correlations of exposure-dated glacier chronologies with millennial scale climate changes (Balco, 2011. The changes in glacial timing generated by only using the most

  12. Engelmann spruce tree-ring chronologies from Fraser Experimental Forest, Colorado: Potential for a long-term temperature reconstruction in the central Rocky Mountains

    Energy Technology Data Exchange (ETDEWEB)

    Brown, P.M.; Shepperd, W.D. [Forest Service, Fort Collins, CO (United States). Rocky Mountain Forest and Range Experiment Station

    1995-12-31

    Tree-ring width chronologies from Engelmann spruce at two treeline sites in the central Rocky Mountains contain similar high and low frequency patterns in ring width, indicative of regional climate control on tree growth. Comparisons of annual ring widths with instrumental climate data show relationships with late spring temperature fluctuations on annual to century time scales. Ring width patterns in the earliest dated trees at one of the sites also infers upward migration in treeline at the site around A.D. 1250. No unusual growth increases were seen in recent years, suggesting that these trees have not recorded warmer conditions possibly associated with global climate change.

  13. Index to Nuclear Safety. A technical progress review by chronology, permuted title, and author. Vol 11, No. 1 through Vol. 16, No. 6

    Energy Technology Data Exchange (ETDEWEB)

    Cottrell, W.B.; Klein, A.

    1976-04-01

    This index to Nuclear Safety covers articles in Nuclear Safety Vol. 11, No. 1 (Jan.-Feb. 1970) through Vol. 16, No. 6 (Nov.-Dec. 1975). Included in the index is a chronological list of articles (including abstract) followed by both a KWIC index and an Author Index. Nuclear Safety is a bimonthly technical progress review prepared by the Nuclear Safety Information Center and covers all safety aspects of nuclear power reactors and associated facilities. The index lists over 300 technical articles in the last six years of publication.

  14. The WAIS Divide deep ice core WD2014 chronology – Part 1: Methane synchronization (68–31 ka BP) and the gas age–ice age difference

    OpenAIRE

    Buizert, C.; Cuffey, K.M.; J. P. Severinghaus; Baggenstos, D.; T. J. Fudge; E. J. Steig; Markle, B. R.; M. Winstrup; R. H. Rhodes; E. J. Brook; Sowers, T. A.; G. D. Clow; Cheng, H.; Edwards, R. L.; Sigl, M.

    2015-01-01

    The West Antarctic Ice Sheet Divide (WAIS Divide, WD) ice core is a newly drilled, high-accumulation deep ice core that provides Antarctic climate records of the past ∼68 ka at unprecedented temporal resolution. The upper 2850 m (back to 31.2 ka BP) have been dated using annual-layer counting. Here we present a chronology for the deep part of the core (67.8–31.2 ka BP), which is based on stratigraphic matching to annual-layer-counted Greenland ice cores using globally we...

  15. Index to Nuclear Safety: a technical progress review by chronology, permuted title, and author, Volume 18 (1) through Volume 22 (6)

    International Nuclear Information System (INIS)

    This index to Nuclear Safety covers articles published in Nuclear Safety, Volume 18, Number 1 (January-February 1977) through Volume 22, Number 6 (November-December 1981). The index is divided into three section: a chronological list of articles (including abstracts), a permuted-title (KWIC) index, and an author index. Nuclear Safety, a bimonthly technical progress review prepared by the Nuclear Safety Information Center, covers all safety aspects of nuclear power reactors and associated facilities. Over 300 technical articles published in Nuclear Safety in the last 5 years are listed in this index

  16. Impacts of Colonial Deforestation on Sediment Organic Carbon Fluxes and Budget Using Black Carbon Chronology: Waiapu Continental Shelf, New Zealand

    Science.gov (United States)

    Wadman, H. M.; Canuel, E. A.; Bauer, J. E.; McNinch, J. E.

    2009-12-01

    Small, mountainous rivers deliver a disproportionate amount of sediment and associated organic matter to coastal regions globally. The Waiapu River, North Island, New Zealand, is characterized by one of the highest sediment yields on earth, providing a model system for studying episodic delivery and preservation of sedimentary organic matter in an energetic, aggradational setting. Hyperpycnal plumes provide the primary mode of sediment delivery, depositing fine-grained sediment as flood layers on the inner shelf. Severe erosion following colonial-era (~1890-1920) slash and burn deforestation increased the sediment yield to the shelf 4- to 5-fold relative to previous levels. Colonial catchment-wide burning also produced black carbon (BC), which may be used to establish chronological control in the heterogeneous inner shelf sediments that are not easily dateable using traditional techniques. While recent work indicates that these inner shelf flood layers sequester ~16-34% of the total fine-grained sediment budget, comparable to the amount preserved on the mid-outer shelf, little is understood about the organic matter associated with these inner shelf sediments. High-resolution seismic reflection data were used to select four representative cores to characterize total sedimentary BC, total organic carbon (TOC) and total nitrogen (TN) sequestered in the inner shelf fine-grained sediments. Soot and graphitic BC (SGBC) was quantified using chemo-thermal oxidation (CTO-375), while coarse-grained BC (CGBC) was quantified using traditional point-counting methodologies. SGBC weight percentages ranged from ~0.01-0.07, and peaked at ~150cm depth in all four cores. This interval corresponds to peak abundance of CGBC as well. The ~150cm interval is interpreted to represent the height of colonial slash and burn deforestation, and is further supported by fining-upward sequences in all of the cores as well as by multiple 14C dates. Overall, SGBC represented an average of 29% (range

  17. Synchronizing the North American Varve Chronology with Greenland ice core records during late MIS 2 using Meteoric 10Be Flux

    Science.gov (United States)

    DeJong, Benjamin D.; Balco, Greg; Ridge, Jack C.; Rood, Dylan H.; Bierman, Paul R.

    2013-04-01

    The North American Varve Chronology (NAVC) is a floating 5700-year sequence of glacial lake varves deposited in the Connecticut River Valley of the northeast US ~18,000-12,500 years ago. The NAVC is an annually resolved record of regional climate and ice-marginal processes at 40-45° N latitude, near the margin of the retreating Laurentide Ice Sheet (LIS). NAVC deposition occurred at the same time as rapid and abrupt Arctic and North Atlantic climate changes that took place during the last deglaciation. Age calibration estimates for the NAVC based on radiocarbon dated plant macrofossils in individual varves imply a relationship between ice-marginal events recorded by the NAVC and climate events recorded in Greenland ice cores. For example, the retreat rate of the LIS up the Connecticut River Valley increased during the Bolling warming in Greenland, a readvance of the LIS margin took place during the Older Dryas cold period, and a correlation between an outburst flood from glacial Lake Iroquois and the Intra-Allerod Cold Period supports the hypothesis that the flood affected North Atlantic thermohaline circulation. On the other hand, a doubling of the ice-margin retreat rate recorded by the NAVC around 16,000 years ago coincides with a relatively cold period in Greenland. Our goal is to investigate the precise time relationship between these two records by synchronizing the NAVC with the Greenland ice core time scale using atmospherically-produced 10Be. Existing 10Be flux records, including those from Greenland ice cores, exhibit solar variability on a range of time scales. Because this variability is globally synchronous, a 10Be flux record for the NAVC can, in principle, be used to align NAVC and ice core timescales. In the first phase of this research we tested this potential by generating 10Be flux records for two 80-year varve sequences and analyzing them using multi-taper spectral analysis for determination of statistically significant periodicities. We were

  18. Assessment of skeletal age using MP 3 and hand-wrist radiographs and its correlation with dental and chronological ages in children

    Directory of Open Access Journals (Sweden)

    Bala M

    2010-06-01

    Full Text Available The purpose of the study was to assess skeletal age using MP 3 and hand-wrist radiographs and to find the correlation amongst the skeletal, dental and chronological ages. One hundred and sixty North-Indian healthy children in the age group 8-14 years, comprising equal number of males and females were included in the study. The children were radiographed for middle phalanx of third finger (MP 3 and hand-wrist of the right hand and intra oral periapical X-ray for right permanent maxillary canine. Skeletal age was assessed from MP 3 and hand-wrist radiographs according to the standards of Greulich and Pyle. The dental age was assessed from IOPA radiographs of right permanent maxillary canine based on Nolla′s calcification stages. Skeletal age from MP 3 and hand-wrist radiographs shows high correlation in all the age groups for both sexes. Females were advanced in skeletal maturation than males. Skeletal age showed high correlation with dental age in 12-14 years age group. Chronological age showed inconsistent correlation with dental and skeletal ages.

  19. Late Pleistocene and Holocene tephrostratigraphy of interior Alaska and Yukon: Key beds and chronologies over the past 30,000 years

    Science.gov (United States)

    Davies, Lauren J.; Jensen, Britta J. L.; Froese, Duane G.; Wallace, Kristi L.

    2016-08-01

    The Aleutian Arc-Alaska Peninsula and Wrangell volcanic field are the main source areas for tephra deposits found across Alaska and northern Canada, and increasingly, tephra from these eruptions have been found further afield in North America, Greenland, and Europe. However, there have been no broad scale reviews of the Late Pleistocene and Holocene tephrostratigraphy for this region since the 1980s, and this lack of data is hindering progress in identifying these tephra both locally and regionally. To address this gap and the variable quality of associated geochemical and chronological data, we undertake a detailed review of the latest Pleistocene to Holocene tephra found in interior Alaska and Yukon. This paper discusses nineteen tephra that have distributions beyond southwest Alaska and that have the potential to become, or already are, important regional markers. This includes three 'modern' events from the 20th century, ten with limited data availability but potentially broad distributions, and six that are widely reported in interior Alaska and Yukon. Each tephra is assessed in terms of chronology, geochemistry and distribution, with new Bayesian age estimates and geochemical data when possible. This includes new major-element geochemical data for Crater Peak 1992, Redoubt 1989-90, and two andesitic tephra from St Michael Island (Tephra D), as well as revised age estimates for Dawson tephra, Oshetna, Hayes set H, Aniakchak CFE II, and the White River Ashes, northern and eastern lobes.

  20. 中国历史纪年数字化初论%A study on the digitalization of historical chronology in China

    Institute of Scientific and Technical Information of China (English)

    苏卫国

    2015-01-01

    Time or historical chronology is the core of historical information and it ’ s very important for the historical truth recognition .While information technology has a strong organizational ability on time ,it hard for it to handle with the historical information due to the limitation of time data standard .The Chinese chronology is different from the west and complex in itself which intense the difficulty of connecting it with the universal time standard.Therefore,the Chinese chronology is changed according to the Christian era .Thus,information distortion ,high cost for ranking and weak compatibility and portability appear which restricts the application effects and developing potential .However,using the Julian date as the basic time standard ,the problems above can be avoided and this can serve our historical recognition efficiently .Related standards are needed to be set .%时间或纪年是历史资料的核心属性,对史实认知至关重要。然而,信息技术对时间元素的强势组织能力,却因时间数据标准的局限乏力于历史时期数据的处理。中国的历史纪年与西方迥异且情况复杂多变,更加剧了与通行时间数据标准融通的难度。于是,把中国历史纪年转为公元年数成为人们将其数字化的折衷处理方法,但信息失真度大、排序成本高、兼容及可移植性差等问题制约了产品的应用效果和发展潜力。以儒略日作为贯通中国历史纪年的基础数据形式,可以克服以上弊病,使信息技术有效服务历史认知,相关标准亟待制定。

  1. New luminescence ages for the Galeria Complex archaeological site: resolving chronological uncertainties on the acheulean record of the Sierra de Atapuerca, northern Spain.

    Directory of Open Access Journals (Sweden)

    Martina Demuro

    Full Text Available The archaeological karstic infill site of Galería Complex, located within the Atapuerca system (Spain, has produced a large faunal and archaeological record (Homo sp. aff. heidelbergensis fossils and Mode II lithic artefacts belonging to the Middle Pleistocene. Extended-range luminescence dating techniques, namely post-infrared infrared stimulated luminescence (pIR-IR dating of K-feldspars and thermally transferred optically stimulated luminescence (TT-OSL dating of individual quartz grains, were applied to fossil-bearing sediments at Galería. The luminescence dating results are in good agreement with published chronologies derived using alternative radiometric dating methods (i.e., ESR and U-series dating of bracketing speleothems and combined ESR/U-series dating of herbivore teeth, as well as biochronology and palaeoenvironmental reconstructions inferred from proxy records (e.g., pollen data. For the majority of samples dated, however, the new luminescence ages are significantly (∼50% younger than previously published polymineral thermoluminescence (TL chronologies, suggesting that the latter may have overestimated the true burial age of the Galería deposits. The luminescence ages obtained indicate that the top of the basal sterile sands (GIb at Galería have an age of up to ∼370 thousand years (ka, while the lowermost sub-unit containing Mode II Acheulean lithics (base of unit GIIa was deposited during MIS 9 (mean age = 313±14 ka; n = 4. The overlying units GIIb-GIV, which contain the richest archaeopalaeontological remains, were deposited during late MIS 8 or early MIS 7 (∼240 ka. Galería Complex may be correlative with other Middle Pleistocene sites from Atapuerca, such as Gran Dolina level TD10 and unit TE19 from Sima del Elefante, but the lowermost archaeological horizons are ∼100 ka younger than the hominin-bearing clay breccias at the Sima de los Huesos site. Our results suggest that both pIR-IR and single-grain TT

  2. OSL chronology of onshore cyclone deposits at Point Lefroy (Exmouth Gulf, Western Australia) - Implications for washover fan formation and regional cyclone activity

    Science.gov (United States)

    Brill, Dominik; May, Simon Matthias; Shah-Hosseini, Majid; Leopold, Matthias; Callow, Nik; Engel, Max; Scheffers, Anja; Brückner, Helmut

    2016-04-01

    Although frequently occurring, little is known about the geological imprint of (pre)historical tropical cyclones (TCs) in Northwestern Australia. Large washover fans at Point Lefroy (Exmouth Gulf) provide unambiguous morphological evidence of flooding by TCs capable to overtop and breach the local coastal barrier. Based on ground penetrating radar, unmanned aerial vehicle survey techniques, as well as geomorphological, sedimentological and chronological investigations, this research aims at reconstructing the formation of the washover fans, and understanding their significance for recording past TC activity. The stratigraphy of the washover fans is characterized by multiple depositional units, which are separated by palaeosurfaces with initial pedogenesis. Combining the chronostratigraphical record of the different washover fans at Point Lefroy is assumed to reflect the regional TC magnitude-frequency pattern, reaching far beyond historical records. While reworking of calcareous faunal remains biases the application of radiocarbon dating, we carried out optically stimulated luminescence (OSL) dating in order to establish a robust chronology of TC-induced washover deposition. OSL dating was challenged by spatially heterogeneous dose rates within the poorly sorted mixture of quartz and coral fragments, by incomplete signal resetting, and by sediment mixing during and, most likely, after transportation. However, by successfully constraining the contribution of each of these factors - using a combination of single-grain quartz dating, quasi-continuous luminescence profiling, spatially resolved dose rate determination, and dose rate modelling - the final chronology gives insight into the evolution of the geo-archive and, ultimately, into the local to regional TC history. Based on up to three sediment profiles from each fan structure, two different washover fans were OSL dated. While contemporaneous deposition at both landforms suggest that the two geomorphological

  3. New luminescence ages for the Galería Complex archaeological site: resolving chronological uncertainties on the acheulean record of the Sierra de Atapuerca, northern Spain.

    Science.gov (United States)

    Demuro, Martina; Arnold, Lee J; Parés, Josep M; Pérez-González, Alfredo; Ortega, Ana I; Arsuaga, Juan L; Bermúdez de Castro, José M; Carbonell, Eudald

    2014-01-01

    The archaeological karstic infill site of Galería Complex, located within the Atapuerca system (Spain), has produced a large faunal and archaeological record (Homo sp. aff. heidelbergensis fossils and Mode II lithic artefacts) belonging to the Middle Pleistocene. Extended-range luminescence dating techniques, namely post-infrared infrared stimulated luminescence (pIR-IR) dating of K-feldspars and thermally transferred optically stimulated luminescence (TT-OSL) dating of individual quartz grains, were applied to fossil-bearing sediments at Galería. The luminescence dating results are in good agreement with published chronologies derived using alternative radiometric dating methods (i.e., ESR and U-series dating of bracketing speleothems and combined ESR/U-series dating of herbivore teeth), as well as biochronology and palaeoenvironmental reconstructions inferred from proxy records (e.g., pollen data). For the majority of samples dated, however, the new luminescence ages are significantly (∼50%) younger than previously published polymineral thermoluminescence (TL) chronologies, suggesting that the latter may have overestimated the true burial age of the Galería deposits. The luminescence ages obtained indicate that the top of the basal sterile sands (GIb) at Galería have an age of up to ∼370 thousand years (ka), while the lowermost sub-unit containing Mode II Acheulean lithics (base of unit GIIa) was deposited during MIS 9 (mean age = 313±14 ka; n = 4). The overlying units GIIb-GIV, which contain the richest archaeopalaeontological remains, were deposited during late MIS 8 or early MIS 7 (∼240 ka). Galería Complex may be correlative with other Middle Pleistocene sites from Atapuerca, such as Gran Dolina level TD10 and unit TE19 from Sima del Elefante, but the lowermost archaeological horizons are ∼100 ka younger than the hominin-bearing clay breccias at the Sima de los Huesos site. Our results suggest that both pIR-IR and single-grain TT

  4. Clumped Isotope Verification of δ18O-Based Freshwater Mussel Shell Growth Chronology for a High-Resolution Climate and River Discharge Record

    Science.gov (United States)

    VanPlantinga, A.; Grossman, E. L.; Passey, B. H.; Randklev, C.

    2015-12-01

    Isotope profiles in freshwater mussel shells can be used to reconstruct climate, water source, and river discharge, but problems arise from variable water temperature and δ18O. To resolve this complexity and expand the application of isotope sclerochronology to the study of past river systems, we measured δ18O and Δ47 in two common freshwater mussel species from the Brazos River in Texas. To compare the environmental record with the shell record and develop a sclerochronology, weekly water temperature and δ18O data were collected from the Brazos River near College Station from January 2012 to August 2013. The river data reveal complex, irregular patterns for predicted aragonite δ18O. Comparing δ18O profiles from micromilled transects (70-200 µm increments) of coeval shell growth within and between shells yielded consistent patterns. Shell δ18O can be accurately matched to predicted δ18O, providing a chronology of shell growth. However, without a water temperature and δ18O record, interpreting a sclerochronology would be impossible. Shell Δ47 can potentially provide a seasonal chronology to verify the δ18O sclerochronology, which would be invaluable for the use of δ18O sclerochronology in historical and ancient shells. For Δ47 analyses, samples were taken at 0.5 mm resolution in presumed seasonal dark and light growth bands. Clumped temperatures range between 21 and 35 ± 4˚C (Henkes et al., 2013) and track the river temperature record, supporting the interpreted shell δ18O chronology. Shell Δ47-calculated water δ18O values range from -1.2 to 1.5 ± 0.9‰ and match river δ18O. High-resolution shell δ18O profiles combined with Δ47 temperatures can reconstruct a weekly history of water δ18O, and with the observed river discharge vs. water δ18O relation, produce a qualitative record of river discharge. These analytical techniques applied to a historical Brazos River mussel shell collected prior to dam construction reveal weekly records of

  5. Chronology and diversity of funerary systems at Marroquíes site (Jaén. An approach from excavations carried out in the streetcar pathway

    Directory of Open Access Journals (Sweden)

    Juan Antonio Cámara Serrano

    2013-02-01

    Full Text Available This paper provides information on three aspects regarding the complexity of the archaeological site of Marroquíes (Jaén, Spain: 1 the composition of the population buried in rock-cut tombs and the different treatment that individuals experienced, especially in relation to their integration into multiple or collective burials and sometimes bones removal; 2 the composition of livestock and its diverse use in ritual; 3 the chronological frame of the burials as an essential step to develop (and especially support any hypothesis about prehistoric populations, and to understand the changes that many bodies experienced along the period of worship that affected them. The available dates have shown that these strategies were developed primarily from the second half of the Third Millennium BC.

  6. Astronomie et chronoligie chez Newton - arguments astronomiques à l'appui de la chronologie de Newton (Astronomical arguments in Newton's Chronology)

    Science.gov (United States)

    Nazé, Yaël

    2012-12-01

    In his Chronology, Newton uses astronomical "evidence" to support its extreme rejuvenation of ancient times. These elements, having a scientific varnish, provide some credibility to the work. They have been fiercely debated for a century, with a gradual undermining of Newton's assumptions. However, this has not dented the prestige of the English scientist. Dans sa Chronologie, Newton utilise des "preuves" astronomiques pour appuyer son rajeunissement extreme des epoques anciennes. Ces elements, au vernis scientifique, donnent une credibilite certaine a l'ensemble. Ils ont donc ete aprement discutes, les debats sapant petit a petit les hypotheses du savant anglais pour finalement porter un coup mortel a l'ensemble. Cela n'a toutefois pas entame le prestige du savant anglais.

  7. A chronology of the PY608E-PC sediment core (Lake Pumoyum Co, southern Tibetan Plateau) based on radiocarbon dating of total organic carbon

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Takahiro, E-mail: twatanabe@geo.kankyo.tohoku.ac.jp [Graduate School of Environmental Studies, Tohoku University, 6-6-20 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8579 (Japan); Graduate School of Science, Tohoku University, 6-3 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8578 (Japan); Nakamura, Toshio [Center for Chronological Research, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8601 (Japan); Matsunaka, Tetsuya [School of Marine Science and Technology, Tokai University, 3-20-1 Orido, Shimizu, Shizuoka 424-0902 (Japan); Nara, Fumiko Watanabe [Graduate School of Science, Tohoku University, 6-3 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8578 (Japan); Zhu Liping; Wang Junbo [Institute of Tibetan Plateau Research, Chinese Academy of Science, No. 18 Shuangqing Road, Haidian District, Beijing 100085 (China); Kakegawa, Takeshi [Graduate School of Science, Tohoku University, 6-3 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8578 (Japan); Nishimura, Mitsugu [School of Marine Science and Technology, Tokai University, 3-20-1 Orido, Shimizu, Shizuoka 424-0902 (Japan)

    2013-01-15

    Paleoclimatic records from the Tibetan Plateau provide important clues for understanding the Asian monsoon and Asian climate systems. To reconstruct climatic and environmental changes in the southern Tibetan Plateau, a 3.77-m-long sediment core (PY608E-PC) was taken from the southeastern part of Lake Pumoyum Co in August 2006. Because terrestrial plant residues are extremely rare in this core, we performed radiocarbon dating on the total organic carbon fraction. We also estimated the old carbon effect and radiocarbon reservoir age of the total organic carbon fraction. Using these estimates, we propose a new radiocarbon chronology for past climatic changes from ca. 12,500 to 700 cal BP. The linear sedimentation rate of the core was founded to be constant at 32.0 cm/kyr, indicating stable sedimentation conditions in Lake Pumoyum Co from the period of the Younger Dryas to the Holocene.

  8. Magnetic Correlation and Chronology of Sediment-cores (HOTRAX) From the Alpha Ridge and Lomonosov Ridge; Preliminary Results and Some Questions

    Science.gov (United States)

    Lovlie, R.; Jakobsson, M.; Wang, Y.; Wallin, A.; Sellén, E.; Polyak, L.

    2006-12-01

    The chronology of Plio-Pleistocene sediment-cores from Central Arctic Ocean retrieved during the Healy-Oden Transarctic expedition in 2005 is attempted constructed using paleomagnetic reversal/excursion stratigraphies and relative paleointensity records combined with stratigraphic variations of mineral magnetic properties. Shipboard whole core magnetic susceptibility measurements revealed surprisingly similar records in cores retrieved between the Mendeleev Ridge and Alpha Ridge; 7 cores can be tied together by more than 15 characteristic susceptibility features, enabling a very detailed and precise correlation. This result suggests lateral uniformity of sediment-composition and only minor variation in deposition rates across this part of the Arctic. Paleomagnetic directions and relative paleointensity-data have so far been obtained from two cores; one from the Alpha Ridge-area, and one collected within the conspicuous depression (gap) across the Lomonosov Ridge. The two cores reveal a large number of short-duration polarity reversals (i.e. excursions), as is a characteristic feature of Arctic Ocean sediment cores. The highly varying lengths of the reversed `polarity' intervals may reflect local variations in accumulation/erosion rates. Relative paleointensity (RPI) curves may be correlated with SINT-800. However, most `excursions' are not associated with intensity-lows, questioning the reality of these excursions as well as the reliability of using SINT-800 as a dating tool. A previously investigated core from the Lomonosov Ridge (AO96-12pc1) also carries a large number of `excursions' with varying lengths. Although the RPI-curve resembles the Alpha Ridge RPI-records, any correlation with SINT-800 to obtain a chronology is presently questionable. We address the following questions: A) Are all - or some of - the inferred excursions artifacts due to undisclosed post-depositional processes? B) May RPI-variations be invariant to geomagnetic field-directions? C) May

  9. The Antarctic ice core chronology (AICC2012: an optimized multi-parameter and multi-site dating approach for the last 120 thousand years

    Directory of Open Access Journals (Sweden)

    D. Veres

    2012-12-01

    Full Text Available The deep polar ice cores provide reference records commonly employed in global correlation of past climate events. However, temporal divergences reaching up to several thousand years (ka exist between ice cores over the last climatic cycle. In this context, we are hereby introducing the Antarctic Ice Core Chronology 2012 (AICC2012, a new and coherent timescale developed for four Antarctic ice cores, namely Vostok, EPICA Dome C (EDC, EPICA Dronning Maud Land (EDML and Talos Dome (TALDICE, alongside the Greenlandic NGRIP record. The AICC2012 time scale has been constructed using the Bayesian tool Datice (Lemieux-Dudon et al., 2010 that combines glaciological inputs and data constraints, including a wide range of relative and absolute gas and ice stratigraphic markers. We focus here on the last 120 ka, whereas the companion paper by Bazin et al., (2012 focuses on the interval 120–800 ka.

    Compared to previous timescales, AICC2012 presents an improved timing for the last glacial inception respecting the glaciological constraints of all analyzed records. Moreover, with the addition of numerous new stratigraphic markers and improved calculation of the lock-in depth (LID based on δ15N data employed as the Datice background scenario, the AICC2012 presents a new timing for the bipolar sequence of events over Marine Isotope Stage 3 associated with the see-saw mechanism, with maximum differences of about 500 yr with respect to the previous Datice-derived chronology of Lemieux-Dudon et al. (2010, hereafter denoted LD2010. Our improved scenario confirms the regional differences for the millennial scale variability over the last glacial period: while the EDC isotopic record (events of triangular shape displays peaks roughly at the same time as the NGRIP abrupt isotopic increases, the EDML isotopic record (events characterized by broader peaks or even extended periods of high isotope values reached the isotopic maximum several centuries

  10. Chronological trends of emission, environmental level and human exposure of POPs over the last 10 years (1999-2010) in Korea: implication to science and policy.

    Science.gov (United States)

    Kim, Seung-Kyu; Yoon, Junheon

    2014-02-01

    Despite the first comprehensive reviewing on POPs status in Korea, a previous review chapter (Departments in Environmental Science, Volume 7, Chapter 2) could not discuss and evaluate the temporal trends and the effect of the efforts and policies invested in POPs control and management, since most data were based on individual research results of academic groups in which POPs could not be systematically monitored in terms of time and space. Recently, we have collected monitoring data long enough in time (over 10 years) and wide enough in space (covering various land-use patterns and the Korean peninsula), which were produced at national monitoring stations under the governmental programs. This study aimed to elucidate the temporal trends of POPs emissions, concentrations in multiple compartments (air, water, soil, sediment, organisms, and marine products), and human exposure. The chronological data available for all the subjects investigated were present only for PCDDs/DFs and coPCBs. Their emission reduction with half-lives of ~2 years was followed by contemporaneous decrease of contamination levels in inland compartments, while a considerably slow or slight reduction occurred in human exposure and its related compartments (fishes and shellfishes as foodstuffs consumed, and marine compartments). The findings prove that a lag-time is present for the efforts of emission reduction to be so much effective as to be reflected directly in human exposure, and such a lag-time can be related with the fates connecting inland and marine environments. PCBs showed faster reduction in human exposure than dioxin-like compounds. As for other POPs, chronological trends and half-lives could not be determined owing to low detection frequencies of PCBs and OCPs in environmental compartments, the absence of monitoring data for OCPs in human exposure, and data limitation for emerging POPs present in recent a few years. Monitoring strategies are also recommended based on this meta-analysis.

  11. Desarrollo de cronologías de ancho de anillos para alerce (Fitzroya cupressoides en Contao y Mirador, Chile Development of tree-ring chronologies for alerce (Fitzroya Cupressoides in Contao and Mirador, Chile

    Directory of Open Access Journals (Sweden)

    EDUARDO NEIRA

    2000-12-01

    Full Text Available Se desarrollaron dos cronologías de ancho de anillos de crecimiento a partir de muestras de alerce (Fitzroya cupressoides (Molina Johnston, colectadas en dos sitios: Contao, Cordillera de los Andes (41º 33'S, 72º 38'W, y Mirador, en la Cordillera de la Costa (40º 10'S, 73º 42'W. En la elaboración de las cronologías se utilizó el programa COFECHA para verificar el cofechado y se desarrolló para cada sitio una cronología utilizando el programa computacional ARSTAN. Se compararon las cronologías Contao y Mirador, con otras existentes para alerce encontrándose una alta similitud de la cronología Contao con la desarrollada para Lenca (41º 33'S, 72º 36' W. Contao presentó los valores más altos en los estadígrafos analizados con relación a las demás cronologías. Se observaron diferencias entre las cronologías provenientes de la Cordillera de la Costa y de los Andes en los últimos 150 años, probablemente producto de explotaciones humanas e incendios ocurridos en la cordillera de la Costa. La correlación con variables climáticas fue similar en su tendencia a la de otros estudios previos, documentando una correlación negativa con las temperaturas y positiva con las precipitaciones del verano anterior al período de crecimientoTwo ring-width chronologies were developed using samples from alerce (Fitzroya cupressoides (Molina Johnston. These were collected from two different sites; Contao, in the Andean Range and Mirador, in the Coastal Range. The series from the each site were cross-dated and COFECHA program was used to verify this process. Once correctly cross-dated, ARSTAN program was used to build up a chronology for each site (Contao and Mirador. These chronologies were compared with other existing chronologies. Contao presented the best statistics when compared to the other chronologies. Differences between chronologies from the Coastal and Andes Ranges were detected mainly during the last 150 years. Before this period

  12. Dynamic of an intra-continental orogenic prism: thermo-chronologic (apatite fission tracks) and tectonic evolution of the axial zone and the piedmont of the west-central Pyrenees

    International Nuclear Information System (INIS)

    This work illustrates the application of thermo chronology to the study of the following geologic issue: the tectonic evolution of the Pyrenean oncologic prism. Thermo-chronology gives information on the vertical movements at the scale of geological eras. Thermo-chronology is based on the following principle: the decay of a nucleus gives birth to a daughter nucleus. Above a specific temperature named closure temperature, the daughter element can diffuse outside the system while below the closure temperature, diffusion is not possible. Consequently thermo-chronology can be considered to date the moment when a mineral goes below a a specific closure temperature. Minerals have different closure temperatures and so by using a suite of thermo-chronometers on a single sample, its cooling path through the crust can be reconstructed. This work focuses on apatite fission track (AFT)analysis which is a low temperature thermo-chronometer. In apatites the temperature range between 60 and 120 Celsius degrees corresponds to the partial annealing zone. The spontaneous fission of one U238 nucleus entails the formation of one fission track. The determination of the initial quantity of U238 is based on the natural steady ratio U238/U235 which equals 137.88. The initial quantity of U235 is determined through the neutron irradiation of the sample. The knowledge of the initial quantity of U238 and the number of tracks in the sample allows the dating of the sample. In this work we combine AFT thermo- chronology with a detailed structural analysis to describe vertical movements related to the thrusting system evolution, and to determine the influence of the latter on the sedimentation/burial/exhumation cycle of the syn-orogenic deposits of the southern fore-land basin

  13. Sedimentology and chronology of the advance and retreat of the last British-Irish Ice Sheet on the continental shelf west of Ireland

    Science.gov (United States)

    Peters, Jared L.; Benetti, Sara; Dunlop, Paul; Ó Cofaigh, Colm; Moreton, Steven G.; Wheeler, Andrew J.; Clark, Christopher D.

    2016-05-01

    The last British-Irish Ice Sheet (BIIS) had extensive marine-terminating margins and was drained by multiple large ice streams and is thus a useful analogue for marine-based areas of modern ice sheets. However, despite recent advances from investigating the offshore record of the BIIS, the dynamic history of its marine margins, which would have been sensitive to external forcing(s), remain inadequately understood. This study is the first reconstruction of the retreat dynamics and chronology of the western, marine-terminating, margin of the last (Late Midlandian) BIIS. Analyses of shelf geomorphology and core sedimentology and chronology enable a reconstruction of the Late Midlandian history of the BIIS west of Ireland, from initial advance to final retreat onshore. Five AMS radiocarbon dates from marine cores constrain the timing of retreat and associated readvances during deglaciation. The BIIS advanced without streaming or surging, depositing a bed of highly consolidated subglacial traction till, and reached to within ∼20 km of the shelf break by ∼24,000 Cal BP. Ice margin retreat was likely preceded by thinning, grounding zone retreat and ice shelf formation on the outer shelf by ∼22,000 Cal BP. This ice shelf persisted for ≤2500 years, while retreating at a minimum rate of ∼24 m/yr and buttressing a >150-km long, 20-km wide, bathymetrically-controlled grounding zone. A large (∼150 km long), arcuate, flat-topped grounding-zone wedge, termed here the Galway Lobe Grounding-Zone Wedge (GLGZW), was deposited below this ice shelf and records a significant stillstand in BIIS retreat. Geomorphic relationships indicate that the BIIS experienced continued thinning during its retreat across the shelf, which led to increased topographic influence on its flow dynamics following ice shelf break up and grounding zone retreat past the GLGZW. At this stage of retreat the western BIIS was comprised of several discrete, asynchronous lobes that underwent several

  14. Episodic speleothem deposition in Ireland during the late Quaternary; implications for Greenland ice core chronology and British-Irish Ice Sheet dynamics

    Science.gov (United States)

    McDermott, Frank; Fankhauser, Adelheid

    2016-04-01

    In shallow caves, episodes of speleothem deposition during the late Quaternary, constrained by U-series dates, provide unequivocal evidence for periods of climate amelioration (presence of liquid water, elevated soil pCO2). U-series data for speleothems from several cave systems in Ireland (Crag, Ballynamintra and Marble Arch) provide clear evidence for episodic speleothem deposition, ranging in age from Marine Isotope Stage (MIS) 7 to the Last Glacial Termination. Speleothem deposition and non-depositional phases within these caves are particularly sensitive to regional-scale climatic conditions, reflecting Ireland's mid-latitudinal, Atlantic margin location. Currently, the earliest dated speleothems from the region are sparsely preserved and thin MIS 7 and MIS 5 flowstones from Ballynamintra and Crag caves respectively. Relatively short-lived depositional phases also occurred at Crag cave during MIS4 and MIS3 and are coeval with the Greenland Interstadials (GI), supporting the recently modified GICC05 Greenland ice core chronology (Buizert et al., 2015), and new providing evidence for synchronous or nearly-synchronous climate amelioration in the N. hemisphere mid- and high-latitudes during the GI events. On the other hand, there is strong evidence that conditions at Crag cave site during stadials and the Heinrich stadials were not conducive to speleothem deposition. Episodes of non-deposition occur synchronously in several speleothems from Crag cave, providing independent constraints on the timing of Heinrich stadials HS-6 to HS-2. The new data also provide independent new insights into the behaviour of the British Irish Ice Sheet (BIIS) during MIS2. In this regard, the presence of a short depositional pulse at 23.35 ± 0.1 ka at Crag cave coincides precisely with the weak and short-lived GI2.2 event within MIS 2, suggesting a dynamic BIIS margin. Simple conductive thermal models for the propagation of surface air temperatures through the limestone karst

  15. Space-time kriging extension of precipitation variability at 12 km spacing from tree-ring chronologies and its implications for drought analysis

    Directory of Open Access Journals (Sweden)

    F. Biondi

    2013-04-01

    Full Text Available Understanding and preparing for future hydroclimatic variability greatly benefits from long (i.e., multi-century records at seasonal to annual time steps that have been gridded at km-scale spatial intervals over a geographic region. Kriging is a geostatistical technique commonly used for optimal interpolation of environmental data, and space-time geostatistical models can improve kriging estimates when long temporal sequences of observations exist at relatively few points on the landscape. Here I present how a network of 22 tree-ring chronologies from single-leaf pinyon (Pinus monophylla in the central Great Basin of North America was used to extend hydroclimatic records both temporally and spatially. First, the Line of Organic Correlation (LOC method was used to reconstruct October–May total precipitation anomalies at each tree-ring site, as these ecotonal environments at the lower forest border are typically moisture limited. Individual site reconstructions were then combined using a hierarchical model of spatio-temporal kriging that produced annual anomaly maps on a 12 × 12 km grid during the period in common among all chronologies (1650–1976. Hydro-climatic episodes were numerically identified and modeled using their duration, magnitude, and peak. Spatial patterns were more variable during wet years than during dry years, and the evolution of drought episodes over space and time could be visualized and quantified. The most remarkable episode in the entire reconstruction was the early 1900s pluvial, followed by the late 1800s drought. The 1930s "Dust Bowl" drought was among the top ten hydroclimatic episodes in the past few centuries. These results directly address the needs of water and natural resource managers with respect to planning for "worst case" scenarios of drought duration and magnitude at the watershed level. For instance, it is possible to analyze which geographical areas are more likely to be impacted by severe and

  16. Annual proxy data from Lago Grande di Monticchio (southern Italy contributing to chronological constraints and abrupt climatic oscillations between 76 and 112 ka

    Directory of Open Access Journals (Sweden)

    C. Martin-Puertas

    2014-06-01

    Full Text Available We present annual sedimentological proxies and sub-annual element scanner data from the Lago Grande di Monticchio (MON sediment record for the sequence 76–112 ka, which, combined with the decadal to centennial resolved pollen assemblage, allow a comprehensive reconstruction of six major abrupt cold and relatively humid spells (MON 1–6 in the central Mediterranean during early phase of the last glaciation. These climatic oscillations are defined by intervals of thicker varves and high Ti-counts and coincide with episodes of forest depletion interpreted as cold and wet oscillations. Based on the independent and slightly revised MON-2014 varve chronology (76–112 ka, a detailed comparison with the Greenland ice-core δ18O record (NGRIP and northern Alps speleothem δ18O data (NALPS is presented. Based on visual inspection of major changes in the proxy data, MON 2–6 are suggested to correlate with GS 25–20. MON 1 (Woillard event, the first and shortest cooling spell in the Mediterranean after a long phase of stable interglacial conditions, has no counterpart in the Greenland ice core, but coincides with the lowest isotope values at the end of the gradual decrease in δ18O in NGRIP during the second half of the GI 25. MON 3 is the least pronounced cold spell and shows gradual transitions, whereas its NGRIP counterpart GS 24 is characterized by sharp changes in the isotope records. MON 2 and MON 4 are the longest most pronounced oscillations in the MON sediments in good agreement with their counterparts in the ice and spelethem records. The length of MON 4 (correlating with GS 22 support the duration of this stadial proposed by the NALPS timescales and suggests ca. 500 yr longer duration than calculated by GICC05 and AICC2012, which would confirm a~possible underestimation in the ice-core. Absolute dating of the cold spells occurring from 112 to 100 ka (MON 1–3 in the MON-2014 chronology is in good agreement with the GICC05 and NALPS

  17. The rock art of palaeolithic style in the Portalón of Cueva Mayor in the Sierra de Atapuerca (Ibeas de Juarros, Burgos: palaeolithic or contemporary chronology?

    Directory of Open Access Journals (Sweden)

    García, Marcos

    2001-06-01

    Full Text Available The doubts shown in different papers on the chronology of the motif painted in the Portalón of Cueva Mayor have caused its revision. A form of analysis is proposed wherein by we pay attention to bibliographic, contextual and graphical questions. The results of the work question the assignment to the Paleolithic of the design; on the contrary we propose that the motif was painted at the beginning of the last century.

    Las dudas manifiestas en las diversas referencias bibliográficas en tomo a la cronología del motivo pintado existente en el Portalón de Cueva Mayor llevaron a la revisión del mismo. Se planteó un protocolo de análisis donde se atendiera a cuestiones historiográficas, contextúales y gráficas. Los resultados del trabajo cuestionan la asignación a momentos paleolíticos de la grafía, planteando, de manera contraria, que la ejecución fue llevada a cabo a inicios del presente siglo.

  18. Geomorphic response and 14C chronology of base-level changes induced by Late Quaternary Caspian Sea mobility (middle Kura Valley, Azerbaijan)

    Science.gov (United States)

    Ollivier, V.; Fontugne, M.; Lyonnet, B.

    2015-02-01

    Recent geomorphological studies in Azerbaijan reveal the importance of climato-eustatic influences on landscape changes in the Caspian Sea Basin during the last 40 ka. Radiocarbon-dated fluvial landforms show that the paleohydrosystem of the middle Kura valley and tributaries responded to regressive and transgressive phases of the Caspian Sea. Chrono-sequences and landforms secured by 32 radiocarbon ages show strong correspondence between fluvial sediment accumulation and oscillations of base level in the Caspian Sea. Six phases of valley floor aggradation (e.g. 27,000-13,000; 11,000-3200; 2900-2100; 1600-1000; 400-150 cal. yr BP) and seven phases of fluvial incision (> 37,000; 37,000-27,000; 13,000-11,000; 3200-2900; 2100-1600; 1000-400; 150-0 cal. yr BP) are recorded. Morphodynamics of the fluvial landscape show a strong correspondence with fluctuation in sea levels in the Caspian Sea: the major Upper Pleistocene-Late Glacial Khvalynian (c.a. 26,000 to 12,400 cal. yr BP) and various Holocene transgressions as well as the Mangyshlak (c.a. 12,000 cal. yr BP) and Derbent (6th-12th century AD) regressions. These data contribute to refining the Caspian relative sea-level curve for the last 30 ka using the chronology of changes in the aggradation or incision in the connected fluvial system.

  19. 丰子恺艺术教育事业年表%A Chronology of Feng Zikai's Career of Art Education

    Institute of Scientific and Technical Information of China (English)

    陈星

    2012-01-01

    丰子恺终其一生未曾离开过艺术教育事业,丰子恺艺术教育事业年表展示其从事艺术教育事业轨迹,并能从一个特定的视角更好地理解丰子恺作为现代作家、艺术家的精神世界、文化行持和生命意义,从而丰富人们对其思想、文化站位与创作的认识,且对过往丰氏研究中的失实表述作必要的匡正和澄清。%Feng Zikai pursued a career of art education all his life. A chronology of such a career can re - enact the trajecto- ry of his pursuit of art education, help better understand his spiritual world, his cultural convictions and the significance of his life as a modern writer and artist and deepen our knowledge of his thoughts, his cultural place and his artistic creation. It can also rectify misrepresentations in previous research on him.

  20. Archaeobotanical evidence on the Neolithisation of Northeast Bulgaria in the Balkan-Anatolian context: chronological framework, plant economy and land use

    Directory of Open Access Journals (Sweden)

    Elena Marinova

    2014-12-01

    Full Text Available The study presents archaeobotanical analyses of four Early Neolithic sites (Koprivets, Orlovets, Dzhulyunitsa, Samovodene from Northeast Bulgaria. Those archaeobotanical data are linked to comprehensive series of 14C dates for the early Neolithic in northeastern Bulgaria allowing their attribution to high resolution radiocarbon chronology. In the considered sites the dominating cereal crop during the Early Neolithic is hulled barley (Hordeum vulgare var. vulgare, followed by einkorn (Triticum monococcum and few emmer (Triticum dicoccum what is a clear difference from the southern parts of Bulgaria where during the early Neolithic the dominating cereal crops are einkorn and emmer. Further principal crops, present from the earliest phases of the Neolithic in the region are lentil - Lens culinaris, pea – Pisum sativum, grass pea – Lathyrus sativus/cicera and flax – Linum usitatissimum. Wide spectrum of finds of gathered plants (at least 11 taxa reflects the use of the natural vegetation resources. Useful for reconstructing the vegetation and land use in the Neolithic are also wood charcoal identifications, indicating apart of oak forests also presence of open vegetation, riparian forests and wetlands. The relatively open vegetation in the surrounding of the early Neolithic settlements could be one of the reasons why the corresponding locations were chosen by the Neolithic people to settle there. On the other hand this open vegetation could be caused by the Neolithic land use and animal husbandry, which have also led to certain reduction of the forests in the immediate surroundings of the settlements.

  1. Thermo chronology by fission tracks of the conjugated rift margins of the Liguro-Provencal basin: Corsica and the Maures-Tanneron Massif

    International Nuclear Information System (INIS)

    We have employed apatite fission-track (AFT) thermo-chronology on granitic and metamorphic samples taken from Corsican and Maures-Tanneron basement rocks as well as alpine 'schistes lustres' units in Corsica, in order to constrain the cooling histories and the tectonic evolution of the Liguro-Provencal basin margins. The AFT data indicate that: -) the Tanneron massif (AFT ages 145- 150 My) appears to record the earliest cooling history, reflecting thermal relaxation related to opening of the Tethys; -) the Maures basement (AFT ages 20-25 My) clearly records a thermo- tectonic evolution associated with Liguro-Provencal rifting; -) the island of Corsica, which was the main focus of this work and which shows a complex geomorphology and a poly-phased tectonic evolution. shows a remarkable zoning in the distribution of AFT ages, reflecting the signature of at least two post-Oligocene thermal events. Those events are related to the opening of Liguro-Provencal basin (20-25 My) in the west, and exhumation of the Hercynian basement related to Tyrrhenian extension (12- 16 My) in the east. In the east-Tenda shear zone, which forms the contact between the alpine units and Hercynian basement in northern Corsica, our results indicate that the Tenda Massif was being exhumed from about 21 Ma onwards. (author)

  2. Chronological development of element concentrations in grapes during growth and ripeness and during fermentation of must determined by instrumental neutron-activation analyses

    International Nuclear Information System (INIS)

    The chronological development of element concentrations during growth and ripeness of grapes described in the literature has only been concerned with the macro elements Mg, K, and Ca. Concentrations of trace elements in must are only described as a snapshot at the end of the ripeness. Therefore, the motivation for the present work was to accompany the growth and the ripening process of grapes successively by systematically determining element concentrations in grapes of Riesling and Cabernet Sauvignon by neutron-activation analyses. While for a number of elements, the concentrations in the grapes increased as a function of grape development (e.g., Na, K, Rb, Al), other concentrations decreased (e.g., Mg, Ca, Mn). These decreases are not only to be attributed to a dilution by an increasing uptake of water during growth, but also by an active transport of the cations out of the berries. Furthermore, the interest focused on the influence of mineral substances on the process of fermentation and on the uptake of trace elements by the yeasts. (orig.)

  3. Dose-rate effects and chronological changes of chromosome aberration rates in spleen cells from mice that are chronically exposed to gamma-ray at low dose rates

    International Nuclear Information System (INIS)

    Dose-rate effects have not been examined in the low dose-rate regions of less than 60-600 mGy/h. Mice were chronically exposed to gamma-ray at 20 mGy/day (approximately 1 mGy/h) up to 700 days and at 1 mGy/day (approximately 0.05 mGy/h) for 500 days under SPF conditions. Chronological changes of chromosome aberration rates in spleen cells were observed along with accumulated doses at both low dose-rates. Unstable aberrations increased in a biphasic manner within 0-2 Gy and 4-14 Gy in 20 mGy/day irradiation. They slightly increased up to 0.5 Gy in 1 mGy/day irradiation. Chromosome aberration rates at 20 mGy/day and 1 mGy/day were compared at the same total doses of 0.5 Gy and 0.25 Gy. They were 2.0 vs. 0.53, and 1.0 vs. 0.47 respectively. Thus, dose-rate effects were observed in these low dose-rate regions. (author)

  4. Sediment accumulation, stratigraphic order, and the extent of time-averaging in lagoonal sediments: a comparison of 210Pb and 14C/amino acid racemization chronologies

    Science.gov (United States)

    Kosnik, Matthew A.; Hua, Quan; Kaufman, Darrell S.; Zawadzki, Atun

    2015-03-01

    Carbon-14 calibrated amino acid racemization (14C/AAR) data and lead-210 (210Pb) data are used to examine sediment accumulation rates, stratigraphic order, and the extent of time-averaging in sediments collected from the One Tree Reef lagoon (southern Great Barrier Reef, Australia). The top meter of lagoonal sediment preserves a stratigraphically ordered deposit spanning the last 600 yrs. Despite different assumptions, the 210Pb and 14C/AAR chronologies are remarkably similar indicating consistency in sedimentary processes across sediment grain sizes spanning more than three orders of magnitude (0.1-10 mm). Estimates of long-term sediment accumulation rates range from 2.2 to 1.2 mm yr-1. Molluscan time-averaging in the taphonomically active zone is 19 yrs, whereas below the depth of final burial (~15 cm), it is ~110 yrs/5 cm layer. While not a high-resolution paleontological record, this reef lagoon sediment is suitable for paleoecological studies spanning the period of Western colonization and development. This sedimentary deposit, and others like it, should be useful, albeit not ideal, for quantifying anthropogenic impacts on coral reef systems.

  5. Longitudinal study of dental development in chimpanzees of known chronological age: implications for understanding the age at death of Plio-Pleistocene hominids.

    Science.gov (United States)

    Anemone, R L; Mooney, M P; Siegel, M I

    1996-01-01

    Reconstruction of life history variables of fossil hominids on the basis of dental development requires understanding of and comparison with the pattern and timing of dental development among both living humans and pongids. Whether dental development among living apes or humans provides a better model for comparison with that of Plio-Pleistocene hominids of the genus Australopithecus remains a contentious point. This paper presents new data on chimpanzees documenting developmental differences in the dentitions of modern humans and apes and discusses their significance in light of recent controversies over the human or pongid nature of australopithecine dental development. Longitudinal analysis of 299 lateral head radiographs from 33 lab-reared chimpanzees (Pan troglodytes) of known chronological age allows estimation of means and standard deviations for the age at first appearance of 8 developmental stages in the mandibular molar dentition. Results are compared with published studies of dental development among apes and with published standards for humans. Chimpanzees are distinctly different from humans in two important aspects of dental development. Relative to humans, chimpanzees show advanced molar development vis a vis anterior tooth development, and chimpanzees are characterized by temporal overlap in the calcification of adjacent molar crowns, while humans show moderate to long temporal gaps between the calcification of adjacent molar crowns. In combination with recent work on enamel incremental markers and CAT scans of developing dentitions of Plio-Pleistocene hominids, this evidence supports an interpretation of a rapid, essentially "apelike" ontogeny among australopithecines. PMID:8928715

  6. Chronological development of element concentrations in grapes during growth and ripeness and during fermentation of must determined by instrumental neutron-activation analyses

    Energy Technology Data Exchange (ETDEWEB)

    Feige, Markus; Hampel, Gabriele; Kratz, Jens Volker; Wiehl, Norbert [Mainz Univ. (Germany). Inst. fuer Kernchemie; Koenig, Helmut [Mainz Univ. (Germany). Inst. fuer Mikrobiologie und Weinforschung; Wagner, Andreas [Weingut Wagner, Essenheim (Germany)

    2014-07-01

    The chronological development of element concentrations during growth and ripeness of grapes described in the literature has only been concerned with the macro elements Mg, K, and Ca. Concentrations of trace elements in must are only described as a snapshot at the end of the ripeness. Therefore, the motivation for the present work was to accompany the growth and the ripening process of grapes successively by systematically determining element concentrations in grapes of Riesling and Cabernet Sauvignon by neutron-activation analyses. While for a number of elements, the concentrations in the grapes increased as a function of grape development (e.g., Na, K, Rb, Al), other concentrations decreased (e.g., Mg, Ca, Mn). These decreases are not only to be attributed to a dilution by an increasing uptake of water during growth, but also by an active transport of the cations out of the berries. Furthermore, the interest focused on the influence of mineral substances on the process of fermentation and on the uptake of trace elements by the yeasts. (orig.)

  7. Role for Sit4p-dependent mitochondrial dysfunction in mediating the shortened chronological lifespan and oxidative stress sensitivity of Isc1p-deficient cells.

    Science.gov (United States)

    Barbosa, António Daniel; Osório, Hugo; Sims, Kellie J; Almeida, Teresa; Alves, Mariana; Bielawski, Jacek; Amorim, Maria Amélia; Moradas-Ferreira, Pedro; Hannun, Yusuf A; Costa, Vítor

    2011-07-01

    Saccharomyces cerevisiae cells lacking Isc1p, an orthologue of mammalian neutral sphingomyelinase 2, display a shortened lifespan and an increased sensitivity to oxidative stress. A lipidomic analysis revealed specific changes in sphingolipids that accompanied the premature ageing of Isc1p-deficient cells under severe calorie restriction conditions, including a decrease of dihydrosphingosine levels and an increase of dihydro-C(26) -ceramide and phyto-C(26) -ceramide levels, the latter raising the possibility of activation of ceramide-dependent protein phosphatases. Consequently, deletion of the SIT4 gene, which encodes for the catalytic subunit of type 2A ceramide-activated protein phosphatase in yeast, abolished the premature ageing and hydrogen peroxide sensitivity of isc1Δ cells. SIT4 deletion also abolished the respiratory defects and catalase A deficiency exhibited by isc1Δ mutants. These results are consistent with catabolic derepression associated with the loss of Sit4p. The overall results show that Isc1p is an upstream regulator of Sit4p and implicate Sit4p activation in mitochondrial dysfunction leading to the shortened chronological lifespan and oxidative stress sensitivity of isc1Δ mutants. PMID:21707788

  8. 交流与争鸣:记中外学者关于夏商周年代的一场论战%Exchange and Debate:A Polimic on Xia-Shang-Zhou Chronology among Chinese and Foreign Scholars

    Institute of Scientific and Technical Information of China (English)

    李润权

    2003-01-01

    Two panels discussing the absolute dates of the Xia, Shang, and Zhou eras were held in the annual meeting of the Association of Asian Studies in Washington, D.C.in April, 2002. The panels focused on five major aspects, which are:whether the chronological results are affected by current politics; the difficulty in the integration of historical documents and archaeological evidences; the reliability of the fitting of radiocarbon dates; different perpectives on the "Current Text" Bamboo Annals; and finally the question of morality in scholarship. The present paper reports the origin and development of these debates and the processes of discussion during the annual meeting. Moreover,it discusses the sources of divergence between the Chinese and foreign scholars on the chronology of Three Dynasties.

  9. Xia - Shang - Zhou Chronology Project and the Study of Archaeological Cultures in the Xia and Shang Periods%夏商周断代工程与夏商考古学文化研究

    Institute of Scientific and Technical Information of China (English)

    杨育彬

    2002-01-01

    Xia-Shang-Zhou Chronology Project is a systematic project with the cooperation of different specialists from the fields of history, archaeology, astronomy and carbon datingtechnology etc.. With five years hard work, this project has released a reliable scientific time table for the Three Dynasties and thus the ancient Chinese history can be traced back to 2070 BC with hard evidence. Besides, the Project has greatly improved the studies of the Xia-Shang-Zhou archaeological cultures.

  10. Rock magnetic response to climatic changes in west Philippine Sea for the last 780 ka:Discussion based on relative paleointensity assisted chronology

    Institute of Scientific and Technical Information of China (English)

    Shulan GE; Xuefa SHI; Gang YANG; Yonghua WU

    2008-01-01

    We conducted rock magnetic and paleomagnetic research on two deep-sea sediment cores from the west Philippine Sea,located to the east of Benham Rise With the length of 4 m and water depth of over 5000 m.At the bottom of core 146 occurs a reversal of inclination and deflection of relative declination,which is recognized as BrunhesMatuyama Polarity Boundary(MBPB).No reversal occurs in core 89.which implies a younger bottom age than that of core 146.Rock magnetic results reveal-magnetic uniformities in mineralogy,concentration and grain size along the two cores,thus relative paleointensity variations are acquired.The three normalizers-anhysteresis remanent magnetization(ARM),magnetic susceptibility(K)and saturation isothermal remanent magnetization(SIRM)are used for normalization to obtain relative Daleointensities.The three normalization results are averaged to indicate the paleoitensity of the cores and are further stacked together to get a synthetic curve for west Philippine Sea(named as WPS800 in this paper).Based on the magnetic correlation between cores and paleointensity to Sint800,we transfer the changes of rock magnetic parameters from depth to time.Furthermore,the astronomically tuned oxygen isotope from ODP site 1143 in the south China Sea is used for the glacial and interglacial indicator.Three concentration proxies(ARM,K and SIRM)and grain size indicators(KARM/SIRM,KARM/K)are examined according to the paleointensity-assisted chronology.The grain size changes in the two cores display a consistent pattem with the climatic changes embodied bv oxygen isotope.The magnetic sizes are usually coarser in glacial periods and finer in interglacial times,which may reflect the influence of chemical erosion rather than fining from sea level rising on the source sediment.Furthermore,the sub-peaks and subtroughs in interglaciations almost correspond with that of oxygen isotope records,which means sedimentation can refect the subtle changes in interglaciations.This kind

  11. The Late Glacial Chronology from Lake Suigestu: A new approach to varve interpolation using frequency distributions of annual sub-layers

    Science.gov (United States)

    Schlolaut, Gordon; Marshall, Michael; Brauer, Achim; Nakagawa, Takeshi; Lamb, Henry; Staff, Richard; Bronk Ramsey, Christopher; Brock, Fiona; Bryant, Charlotte; 2006 Project Members, Suigetsu

    2010-05-01

    The 1993 sediment core from Lake Suigetsu is one of the most comprehensive terrestrial radiocarbon records. It is extremely rich in leaf fossils, providing a unique, truly atmospheric record of radiocarbon for the last 10-50 kyr BP (Kitagawa & van der Plicht, 2000). Since the Lake Suigetsu sediment is annually laminated (varved) for much of its depth it is suitable for extending the terrestrial radiocarbon calibration model up to 50 kyr BP. However, the data presented by Kitagawa & van der Plicht (2000) significantly diverged from alternative, marine-based calibration datasets, due to gaps in the sediment profile and varve counting uncertainties (Staff et al., 2009). In 2006 four new parallel cores were recovered from Lake Suigetsu and combined to construct a new complete and continuous master profile (SG06). Along with a new program of AMS radiocarbon measurement, varve counting is being carried out using two different techniques: i) thin section microscopy and ii) high-resolution X-ray fluorescence and X-radiography. In addition, a novel interpolation approach has been developed. First results are presented for the Late Glacial (10,200 - 15,000 kyr BP). The U-Oki Tephra at the top of this interval is used as tie point for the floating varve count chronology. Initially, the two counting methods are carried out independently. The results are then compared in detail to identify the differences down to the sub-mm scale. This new approach substantially reduces internal error and results in a greater degree of accuracy than previously possible. Due to poor varve preservation in some sediment intervals, the counts of these sections have to be interpolated. Commonly, interpolation is carried out manually using sedimentation rate estimates from neighbouring sections. The new approach presented here is based on an automated analysis of frequency distributions of annual sub-layers from the compromised section itself, allowing an estimate of the sedimentation rate unbiased

  12. Wilbur and Orville Wright: A Reissue of a Chronology Commemorating the Hundredth Anniversary of the Birth of Orville Wright, August 19, 1871

    Science.gov (United States)

    Renstrom, Arthur George (Compiler)

    2003-01-01

    During the year 2003, hundreds of events will mark the one-hundredth anniversary of the Wright brothers historic first flights at Kitty Hawk, North Carolina. The centennial year will witness exhibitions, lectures, television documentaries, films, air shows, flight recreations of Wright aircraft, the issuing of postage stamps and medals, the publication of dozens of new books and articles, and numerous other commemorative activities. One of these events, although not likely to make the evening news, is among the most important of all in terms of a lasting contribution to the observance of this ultimate aviation milestone: the reprinting of Arthur G. Renstrom WIlbur & Orville Wrght: A Chronology Commemorating the Hundredth Anniversary of the Birth of Orville Wright, August 19, 1871. Since its appearance in 1975, Wilbur end Orville Wright: A Chronology has become indispensable to students and authors concerned with the life and work of the famous brothers. No doubt every book on the subject published in the last quarter century, including three of my own, was written with this treasure close at hand. This volume is far more than a simple compilation of dates and facts. Renstrom was a master reference librarian and bibliographer with a passion for aviation and the Wright brothers. He brought his considerable research skills to bear on the topic, and the result is a richly detailed, ever-informative, often entertaining walk through the lives and achievements of these two extraordinary individuals. Renstrom was not content to offer a date with a one-line tidbit. His entries are brimming with information. This is a highly readable reference work that, believe it or not, can be enjoyably read from cover to cover. The project was clearly a labor of love by a talented professional. During most of the last twenty years, I have been privileged to be the curator of the 1903 Wright Flyer at the Smithsonian Institution s National Air and Space Museum. The position brings a steady

  13. Roles of Treg/Th17 Cell Imbalance and Neuronal Damage in the Visual Dysfunction Observed in Experimental Autoimmune Optic Neuritis Chronologically.

    Science.gov (United States)

    Liu, Yuanyuan; You, Caiyun; Zhang, Zhuhong; Zhang, Jingkai; Yan, Hua

    2015-12-01

    Optic neuritis associated with multiple sclerosis and its animal model, experimental autoimmune optic neuritis (EAON), is characterized by inflammation, T cell activation, demyelination, and neuronal damage, which might induce permanent vision loss. Elucidating the chronological relationship among the features is critical for treatment of demyelinating optic neuritis. EAON was induced in C57BL/6 mice immunized with myelin oligodendrocyte glycoprotein subcutaneously, and visual function was assessed by flash-visual evoked potential (F-VEP) at days 7, 11, 14, 19, 23, 28 post-immunization. Retinal ganglion cell (RGC) apoptosis was measured by terminal-deoxynucleotidyl transferase-mediated nick-end labeling. Demyelination and axonal damage were verified with myelin basic protein (MBP) and β-amyloid precursor protein staining, respectively. Real-time polymerase chain reaction quantified IL-17, IL-1β, TGF-β, FoxP3, IL-6, and IL-10 mRNA expression in the optic nerve, as well as FoxP3 and IL-17 staining. Systemic changes of Th17 and Treg cells were tested by flow cytometry in spleen. F-VEP latency was prolonged at 11 days and peaked at 23 days commensurate with demyelination. However, F-VEP amplitude was reduced at 11 days, preceding axon damage, and was exacerbated at 23 days when a peak in RGC apoptosis was detected. Th17 cells up-regulated as early as 7 days and peaked at 11 days, while Treg cells down-regulated inversely compared to Th17 cells change as verified by IL-17 and FoxP3 expression; spleen cell samples were slightly different, demonstrating marked changed at 14 days. Treg/Th17 cell imbalance in the optic nerve precedes and may initiate neuronal damage of axons and RGCs. These changes are commensurate with the appearances of visual dysfunction reflected in F-VEP and hence may offer a novel therapeutic avenue for vision preservation.

  14. Why would we use the Sediment Isotope Tomography (SIT) model to establish a 210Pb-based chronology in recent-sediment cores?

    International Nuclear Information System (INIS)

    After half a century, the use of unsupported 210Pb (210Pbexc) is still far off from being a well established dating tool for recent sediments with widespread applicability. Recent results from the statistical analysis of time series of fluxes, mass sediment accumulation rates (SAR), and initial activities, derived from varved sediments, place serious constraints to the assumption of constant fluxes, which is widely used in dating models. The Sediment Isotope Tomography (SIT) model, under the assumption of non post-depositional redistribution, is used for dating recent sediments in scenarios in that fluxes and SAR are uncorrelated and both vary with time. By using a simple graphical analysis, this paper shows that under the above assumptions, any given 210Pbexc profile, even with the restriction of a discrete set of reference points, is compatible with an infinite number of chronological lines, and thus generating an infinite number of mathematically exact solutions for histories of initial activity concentrations, SAR and fluxes onto the SWI, with these two last ranging from zero up to infinity. Particularly, SIT results, without additional assumptions, cannot contain any statistically significant difference with respect to the exact solutions consisting in intervals of constant SAR or constant fluxes (both being consistent with the reference points). Therefore, there is not any benefit in its use as a dating tool without the explicit introduction of additional restrictive assumptions about fluxes, SAR and/or their interrelationship. - Highlights: • The 210Pb-based method for dating recent sediments is of a widespread use. • Recent results limit the use of the simplifying assumption of constant fluxes. • SIT model claims to solve scenarios where fluxes and SAR independently vary with time. • The paper shows how SIT model lacks of sound physical basis. • A dating tool is only possible by introducing additional restrictive assumptions

  15. A cosmogenic 10Be chronology for the local last glacial maximum and termination in the Cordillera Oriental, southern Peruvian Andes: Implications for the tropical role in global climate

    Science.gov (United States)

    Bromley, Gordon R. M.; Schaefer, Joerg M.; Hall, Brenda L.; Rademaker, Kurt M.; Putnam, Aaron E.; Todd, Claire E.; Hegland, Matthew; Winckler, Gisela; Jackson, Margaret S.; Strand, Peter D.

    2016-09-01

    Resolving patterns of tropical climate variability during and since the last glacial maximum (LGM) is fundamental to assessing the role of the tropics in global change, both on ice-age and sub-millennial timescales. Here, we present a10Be moraine chronology from the Cordillera Carabaya (14.3°S), a sub-range of the Cordillera Oriental in southern Peru, covering the LGM and the first half of the last glacial termination. Additionally, we recalculate existing 10Be ages using a new tropical high-altitude production rate in order to put our record into broader spatial context. Our results indicate that glaciers deposited a series of moraines during marine isotope stage 2, broadly synchronous with global glacier maxima, but that maximum glacier extent may have occurred prior to stage 2. Thereafter, atmospheric warming drove widespread deglaciation of the Cordillera Carabaya. A subsequent glacier resurgence culminated at ∼16,100 yrs, followed by a second period of glacier recession. Together, the observed deglaciation corresponds to Heinrich Stadial 1 (HS1: ∼18,000-14,600 yrs), during which pluvial lakes on the adjacent Peruvian-Bolivian altiplano rose to their highest levels of the late Pleistocene as a consequence of southward displacement of the inter-tropical convergence zone and intensification of the South American summer monsoon. Deglaciation in the Cordillera Carabaya also coincided with the retreat of higher-latitude mountain glaciers in the Southern Hemisphere. Our findings suggest that HS1 was characterised by atmospheric warming and indicate that deglaciation of the southern Peruvian Andes was driven by rising temperatures, despite increased precipitation. Recalculated 10Be data from other tropical Andean sites support this model. Finally, we suggest that the broadly uniform response during the LGM and termination of the glaciers examined here involved equatorial Pacific sea-surface temperature anomalies and propose a framework for testing the viability

  16. Hf isotope compositions and chronology of magmatic zircons from Tarim continental flood basalts: implications for magmatic evolution of the Early Permian Tarim Large Igneous Province in NW China

    Science.gov (United States)

    Li, Y.; Li, Z.; Yu, X.; Langmuir, C. H.; Yang, S.; Chen, H.

    2013-12-01

    The Early Permian Tarim Large Igneous Province (TLIP) in the Tarim cratonic block of northwestern China has been largely regarded to be genetically linked with a mantle plume. Recently, some euhedral zircon crystals with magmatic growth zoning have been obtained from the Tarim continental flood basalts (TCFB) for detailed U-Pb chronological and genetic study. The zircons have the concordant 206Pb/238U ages of 297~283 Ma, coinciding with the previously reported whole-rock 40K/39Ar and 40Ar/39Ar ages (292~283 Ma) of their host basalts. In-situ LA-MC-ICPMS Lu-Hf isotopic analyses of Early Permian zircons from the Keping area of the TCFB reveal that the zircons from two basalt sub-groups (Groups 1a, 1b) have a narrow range of 176Hf/177Hf ratios between 0.282422 and 0.282568. Their corresponding ɛHf(t) (t = 290 Ma) values (-6.8~-1.4) are generally lower than their host basalts (-2.3~2.1), and distinctively different from the intrusive rocks (3.0~7.1) and their zircons (4.9~8.8) from the TLIP and the Precambrian crustal rocks (coherently depleting trend on Sr-Nd-Hf isotopic compositions from the earlier erupted basalts , and then to later emplaced intrusive rocksin the TLIP, a magmatic evolution model is suggested, which a rising mantle plume was continuously injecting depleted mantle components to the magma source region of the TLIP at the bottom of the SCLM under the Tarim block, then produced the various igneous rock units in the TLIP.

  17. {sup 14}C chronology of the oldest Scandinavian church in use. An AMS/PIXE study of lime lump carbonate in the mortar

    Energy Technology Data Exchange (ETDEWEB)

    Lindroos, Alf, E-mail: alf.lindroos@abo.fi [Geology and Mineralogy, Department of Natural Sciences, Åbo Akademi University (Finland); Art History, Faculty of Art, Åbo Akademi University (Finland); Ranta, Heikki [Diocese of Lund, Church of Sweden (Sweden); Heinemeier, Jan [AMS " 1" 4C Dating Laboratory, Department of Physics and Astronomy, University of Aarhus (Denmark); Lill, Jan-Olof [Accelerator Laboratory, Turku PET Centre, Åbo Akademi University (Finland)

    2014-07-15

    Mortar dating was applied to newly revealed, original mortar in the church of Dalby in Scania, southern Sweden which is considered to be the oldest still standing church in Scandinavia. Small white lime lumps were sampled by chipping from the supporting pillars in the interior of the church. Special emphasis was in sampling lime lumps because the church is situated in the Scania limestone area and aggregate limestone contamination was anticipated in the bulk mortars. Earlier studies have, however, shown that lime lumps do not contain aggregate material but only possible limestone rests from incomplete calcination. The sampled material was prepared for radiocarbon AMS dating. The carbonate in the lime lumps was hydrolyzed according to the sequential leaching technique developed for the Århus {sup 14}C laboratory in Denmark. Prior to the hydrolysis the lime lumps were examined for dead-carbon contamination using a stereo microscope and cathodoluminescence. The lime lumps displayed heterogeneous carbonate luminescence. This is, however, common and it was not considered a problem because carbonate growth in changing pH/Eh conditions often leads to changing luminescence colors. Two lumps had little dead carbon contamination and an early second millennium {sup 14}C signature. One lump, however, seemed to be heavily contaminated with dead carbon. Since the sample passed the microscopic screening, the leftovers of the lump was subjected to PIXE analysis and compared with the other two lumps. The well-defined, early 2nd millennium {sup 14}C age of the lime lumps of this particular church is an important contribution to the discussion on stone church chronology in Scandinavia.

  18. Determination of chronological heavy metal deposition and pollution intensity in the bottom sediments of Mumbai Harbour Bay, India using 137Cs as tracer

    International Nuclear Information System (INIS)

    Downcore variation of trace metals in sediment cores along the coastal line is one of the markers to assess the intrusion of industrial pollutants into the aquatic environment. Fifty sediment core samples from the Mumbai Harbour Bay (MHB), were studied for the trace element content. MHB is a recipient of effluents from different industries situated all along its coast around Thane-Belapur region. The average concentrations of Titanium (Ti), Manganese (Mn), Iron (Fe), Nickel (Ni), Copper (Cu), Zinc (Zn) were determined by inductively coupled plasma-optical emission spectroscopy and complemented by analysing with energy dispersive X-ray fluorescence spectrometry. In addition to this, depth profiles of K and Ca were also studied to assess the homogeneity of the geological strata of the region. Trace metals such as Cu, Ni and Zn show enrichment between 16 to 28 cm, whereas, uniform distribution through out the core was observed for K, Ca, Ti, Mn and Fe. Chronology of the heavy metal deposition was predicated based on the average sedimentation rate (0.92 ± 0.08 cm year-1) derived using depth-wise 137Cs concentration profile in core of bottom sediment. The results of the analysis showed that MHB had received excess inputs of Cu, Ni and Zn in the year 1981, 1988 and 1982, respectively. Surface concentration of Cu, Ni, Zn and Fe compared to the reference site indicates moderate pollution in the recent years whereas for elements K, Ca, Ti and Mn, the values are normal indicating MHB unpolluted for the latter elements. (author)

  19. Prehistoric chronology of Madhya Pradesh

    Digital Repository Service at National Institute of Oceanography (India)

    Gaur, A.S.

    Madhya Pradesh is very rich in archaeological wealth, with availability of remains starting from Early Stone Age to Historical period. Several Stone Age sites have been brought to light specially in districts of Hoshangabad, Narsinghpur, Mandla...

  20. When erosion ruins the chronology

    Science.gov (United States)

    Wolters, Steffen; Enters, Dirk; Blume, Katharina; Lücke, Andreas

    2016-04-01

    Human land-use has considerably shaped the landscape of north-western Germany over the past millennia. Deforestation and agriculture created a predominantly open scenery preserved until today with only a few remnants of former landscape elements such as woodlands, peat bogs, heath lands and lakes. Here we present a multi-proxy approach including sedimentological and geochemical parameters (e. g. element concentrations and stable isotopes) as well as biological proxies (pollen, macro fossils and diatoms) combined with an archaeological site analysis to investigate the effects of prehistoric land-use on lake systems and their catchment areas with a special focus on changes of the water quality, e. g. eutrophication and acidification and its natural regeneration during phases of weaker land-use impact. The study reveals a millenia-long history of erosion processes caused by successive selective woodland clearances starting in Neolithic Times. The geochemical evidence of soil erosion is recorded by distinct peaks of the terrigenic elements K and Ti. However, due to (1) the low sensitivy of the XRF scanner for Si and (2) the prevalence of diatom related biogenic silicon XRF-scanning of highly organic lake sediments fails to reflect the actual sand input caused by erosion. Particularly single quartz grains are not detected in the organic sediment matrix. Therefore we make successful use of mineral grain analysis which previously has only been applied to record aeolian input in bogs. K and Ti concentrations are not correlated with the content of mineral grains which suggest two different erosion processes. Our efforts to construct robust age-depth relationships based on AMS 14C-dates of terrestrial plant macrofossils reveal a specific dating issue of northwest German lakes. Especially in younger sediments we observe 14C-dates which are on the one hand too old and on the other hand among themselves roughly contemporaneous. We explain this feature with the extensive bog growth since Neolithic times which eventually reached the lake shores and water level fluctuations of the lakes. Successive erosion of the bog margins in the course of anthropogenic disturbance of wetland sites caused the observed contamination of lacustrine sediments with older material. Amino acid dating, OSL-dating and tephrochronology are suitable alternatives to surmount the dating difficulties inherent in northwest German lakes.

  1. 210Pb-226Ra chronology reveals rapid growth rate of Madrepora oculata and Lophelia pertusa on world's largest cold-water coral reef

    Science.gov (United States)

    Sabatier, P.; Reyss, J.-L.; Hall-Spencer, J. M.; Colin, C.; Frank, N.; Tisnérat-Laborde, N.; Bordier, L.; Douville, E.

    2012-03-01

    Here we show the use of the 210Pb-226Ra excess method to determine the growth rate of two corals from the world's largest known cold-water coral reef, Røst Reef, north of the Arctic circle off Norway. Colonies of each of the two species that build the reef, Lophelia pertusa and Madrepora oculata, were collected alive at 350 m depth using a submersible. Pb and Ra isotopes were measured along the major growth axis of both specimens using low level alpha and gamma spectrometry and trace element compositions were studied. 210Pb and 226Ra differ in the way they are incorporated into coral skeletons. Hence, to assess growth rates, we considered the exponential decrease of initially incorporated 210Pb, as well as the increase in 210Pb from the decay of 226Ra and contamination with 210Pb associated with Mn-Fe coatings that we were unable to remove completely from the oldest parts of the skeletons. 226Ra activity was similar in both coral species, so, assuming constant uptake of 210Pb through time, we used the 210Pb-226Ra chronology to calculate growth rates. The 45.5 cm long branch of M. oculata was 31 yr with an average linear growth rate of 14.4 ± 1.1 mm yr-1 (2.6 polyps per year). Despite cleaning, a correction for Mn-Fe oxide contamination was required for the oldest part of the colony; this correction corroborated our radiocarbon date of 40 yr and a mean growth rate of 2 polyps yr-1. This rate is similar to the one obtained in aquarium experiments under optimal growth conditions. For the 80 cm-long L. pertusa colony, metal-oxide contamination remained in both the middle and basal part of the coral skeleton despite cleaning, inhibiting similar age and growth rate estimates. The youngest part of the colony was free of metal oxides and this 15 cm section had an estimated a growth rate of 8 mm yr-1, with high uncertainty (~1 polyp every two to three years). We are less certain of this 210Pb growth rate estimate which is within the lowermost ranges of previous growth

  2. Geomorphometric reconstruction of post-eruptive surfaces of the Virunga Volcanic Province (East African Rift), constraint of erosion ratio and relative chronology

    Science.gov (United States)

    Lahitte, Pierre; Poppe, Sam; Kervyn, Matthieu

    2016-04-01

    Quaternary volcanic landforms result from a complex evolution, involving volcanic constructional events and destructive ones by collapses and long-term erosion. Quantification, by morphometric approaches, of the evolution through time of the volcano shape allows the estimation of relative ages between volcanoes sharing the same climate and eruptive conditions. We apply such method to six volcanoes of the Virunga Volcanic Province in the western branch of the East African Rift Valley that still has rare geochronological constraints. As they have comparable sizes, volcanic history and erupted products, these edifices may have undergone comparable conditions of erosion which justify the deduction of relative chronology from their erosion pattern. Our GIS-based geomorphometric approach, the SHAPEVOLC algorithm, quantifies erupted or dismantled volumes by numerically modeling topographies resulting from the eruptive construction of each volcano. Constraining points are selected by analyses of morphometric properties of each cell of the current DEM, as the loci where the altitude is still representative of the un-eroded volcanic surfaces. A primary elevation surface is firstly adjusted to these constraining points by modeling a first-order pseudo-radial surface defined by: 1. the curve best fitting the concave-upwards volcano profile; 2. the location and elevation of the volcano summit; and 3. the possible eccentricity and azimuth parameters that allow to stretch and contract contours to adjust the shape of the model to the elliptically-shaped surface of the volcano. A second-order surface is next computed by local adjustment of the first-order surface to the constraining points to obtain the definitive primary elevation surface of the considered volcanic construct. Amount of erosion is obtained by summing the difference in elevation between reconstructed surfaces and current ones that allows to establish relative ages of volcanoes. For the 6 studied Virunga volcanoes

  3. Chronology and shock history of the Bencubbin meteorite: A nitrogen, noble gas, and Ar-Ar investigation of silicates, metal and fluid inclusions

    Science.gov (United States)

    Marty, Bernard; Kelley, Simon; Turner, Grenville

    2010-11-01

    We have investigated the distribution and isotopic composition of nitrogen and noble gases, and the Ar-Ar chronology of the Bencubbin meteorite. Gases were extracted from different lithologies by both stepwise heating and vacuum crushing. Significant amounts of gases were found to be trapped within vesicles present in silicate clasts. Results indicate a global redistribution of volatile elements during a shock event caused by an impactor that collided with a planetary regolith. A transient atmosphere was created that interacted with partially or totally melted silicates and metal clasts. This atmosphere contained 15N-rich nitrogen with a pressure ⩾3 × 10 5 hPa, noble gases, and probably, although not analyzed here, other volatile species. Nitrogen and noble gases were re-distributed among bubbles, metal, and partly or totally melted silicates, according to their partition coefficients among these different phases. The occurrence of N 2 trapped in vesicles and dissolved in silicates indicates that the oxygen fugacity ( fO2) was greater than the iron-wüstite buffer during the shock event. Ar-Ar dating of Bencubbin glass gives an age of 4.20 ± 0.05 Ga, which probably dates this impact event. The cosmic-ray exposure age is estimated at ˜40 Ma with two different methods. Noble gases present isotopic signatures similar to those of "phase Q" (the major host of noble gases trapped in chondrites) but elemental patterns enriched in light noble gases (He, Ne and Ar) relative to Kr and Xe, normalized to the phase Q composition. Nitrogen isotopic data together with 40Ar/ 36Ar ratios indicate mixing between a 15N-rich component (δ 15N = +1000‰), terrestrial N, and an isotopically normal, chondritic N. Bencubbin and related 15N-rich meteorites of the CR clan do not show stable isotope (H and C) anomalies, precluding contribution of a nucleosynthetic component as the source of 15N enrichments. This leaves two possibilities, trapping of an ancient, highly fractionated

  4. Pd-Ag chronology of volatile depletion, crystallization and shock in the Muonionalusta IVA iron meteorite and implications for its parent body

    Science.gov (United States)

    Horan, M. F.; Carlson, R. W.; Blichert-Toft, J.

    2012-10-01

    Muonionalusta, a Group IVA iron meteorite, was analyzed for its 107Pd-107Ag isotope systematics by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) in order to better constrain the initial Solar System abundance of 107Pd and to provide high resolution chronology of the evolution of its parent body. Six metal samples from Muonionalusta yield Ag abundances between 0.1012 and 1.461 ng/g, 107Ag/109Ag between 1.131 and 1.805, with 108Pd/109Ag ratios of 2201 to 52,300. The metal Pd/Ag and Ag isotopic data are correlated with a slope corresponding to a 107Pd/108Pd of (2.15±0.30)×10-5. If the Pd-Ag and Pb-Pb isotope systems closed at the same time in Muonionalusta, i.e., 2-3 Ma after CAI formation, then an initial Solar System ratio of 107Pd/108Pd=(2.8±0.5)×10-5 can be inferred. One troilite sample contains 8.478 ng/g Ag and has a 107Ag/109Ag ratio of 1.0833; its Pd concentration is 205.2 ng/g corresponding to a low 108Pd/109Ag of 13.56. The Pd-Ag results for this troilite plot near the extrapolation of the line passing through the metal points and define an initial 107Ag/109Ag that is substantially higher than chondritic, indicating that Muonionalusta formed from a precursor with high Pd/Ag. Pd and Ag concentrations in Muonionalusta metal suggest fractional crystallization from a source having Pd/Ag>4500, but the initial Ag isotopic composition for Muonionalusta troilite limits the duration of the high Pd/Ag to an interval of ≤0.6 Ma before cooling to closure of the Pd-Ag system. This result suggests that depletion of Ag and other volatile elements occurred shortly before accretion and cooling of the IVA parent body, and may have been associated with violent disruption of a progenitor to the IVA parent. Another troilite sample, its chromite inclusions and adjacent metal were isotopically homogenized locally after 107Pd had decayed, possibly by a later episode of shock >50 Ma after Solar System formation.

  5. Chronologically scheduled snacking with high-protein products within the habitual diet in type-2 diabetes patients leads to a fat mass loss: a longitudinal study

    Directory of Open Access Journals (Sweden)

    Martínez J Alfredo

    2011-07-01

    Full Text Available Abstract Background Obesity is the most relevant overnutrition disease worldwide and is associated to different metabolic disorders such as insulin resistance and type-2 diabetes. Low glycemic load foods and diets and moderately high protein intake have been shown to reduce body weight and fat mass, exerting also beneficial effects on LDL-cholesterol, triglyceride concentrations, postprandial glucose curve and HDL-cholesterol levels. The present study aimed at studying the potential functionality of a series of low glycemic index products with moderately high protein content, as possible coadjuvants in the control of type-2 diabetes and weight management following a chronologically planned snacking offer (morning and afternoon. Methods The current trial followed a single group, sequential, longitudinal design, with two consecutive periods of 4 weeks each. A total of 17 volunteers participated in the study. The first period was a free living period, with volunteers' habitual ad libitum dietary pattern, while the second period was a free-living period with structured meal replacements at breakfast, morning snack and afternoon snack, which were exchanged by specific products with moderately high protein content and controlled low glycemic index, following a scheduled temporal consumption. Blood extractions were performed at the beginning and at the end of each period (free-living and intervention. Parameters analysed were: fasting glucose, insulin, glycosylated hemoglobin, total-, HDL- and LDL-cholesterol, triglyceride, C - reactive protein and Homocysteine concentrations. Postprandial glucose and insulin were also measured. Anthropometrical parameters were monitored each 2 weeks during the whole study. Results A modest but significant (p = 0.002 reduction on body weight (1 kg was observed during the intervention period, mainly due to the fat mass loss (0.8 kg, p = 0.02. This weight reduction was observed without apparently associated changes in

  6. 210Pb-226Ra chronology reveals rapid growth rate of Madrepora oculata and Lophelia pertusa on world's largest cold-water coral reef

    Directory of Open Access Journals (Sweden)

    N. Tisnérat-Laborde

    2012-03-01

    Full Text Available Here we show the use of the 210Pb-226Ra excess method to determine the growth rate of two corals from the world's largest known cold-water coral reef, Røst Reef, north of the Arctic circle off Norway. Colonies of each of the two species that build the reef, Lophelia pertusa and Madrepora oculata, were collected alive at 350 m depth using a submersible. Pb and Ra isotopes were measured along the major growth axis of both specimens using low level alpha and gamma spectrometry and trace element compositions were studied. 210Pb and 226Ra differ in the way they are incorporated into coral skeletons. Hence, to assess growth rates, we considered the exponential decrease of initially incorporated 210Pb, as well as the increase in 210Pb from the decay of 226Ra and contamination with 210Pb associated with Mn-Fe coatings that we were unable to remove completely from the oldest parts of the skeletons. 226Ra activity was similar in both coral species, so, assuming constant uptake of 210Pb through time, we used the 210Pb-226Ra chronology to calculate growth rates. The 45.5 cm long branch of M. oculata was 31 yr with an average linear growth rate of 14.4 ± 1.1 mm yr−1 (2.6 polyps per year. Despite cleaning, a correction for Mn-Fe oxide contamination was required for the oldest part of the colony; this correction corroborated our radiocarbon date of 40 yr and a mean growth rate of 2 polyps yr−1. This rate is similar to the one obtained in aquarium experiments under optimal growth conditions. For the 80 cm-long L. pertusa colony, metal-oxide contamination remained in both the middle and basal part of the coral skeleton despite cleaning, inhibiting similar age and growth rate estimates. The youngest part of the colony was free of metal oxides and this 15 cm section had an estimated a growth rate of 8 mm yr−1, with high uncertainty (~1 polyp every two to three years. We are less certain of this 210Pb growth rate estimate which is within the lowermost

  7. Combined ESR/U-series chronology of Acheulian hominid-bearing layers at Trinchera Galería site, Atapuerca, Spain.

    Science.gov (United States)

    Falguères, Christophe; Bahain, Jean-Jacques; Bischoff, James L; Pérez-González, Alfredo; Ortega, Ana Isabel; Ollé, Andreu; Quiles, Anita; Ghaleb, Bassam; Moreno, Davinia; Dolo, Jean-Michel; Shao, Qingfeng; Vallverdú, Josep; Carbonell, Eudald; Bermúdez de Castro, Jose María; Arsuaga, Juan Luis

    2013-08-01

    The Sierra de Atapuerca, northern Spain, is known from many prehistoric and palaeontological sites documenting human prehistory in Europe. Three major sites, Gran Dolina, Galería and Sima del Elefante, range in age from the oldest hominin of Western Europe dated to 1.1 to 1.3 Ma (millions of years ago) at Sima del Elefante to c.a. 0.2 Ma on the top of the Galería archaeological sequence. Recently, a chronology based on luminescence methods (Thermoluminescence [TL] and Infrared Stimulated Luminescence [IRSL]) applied to cave sediments was published for the Gran Dolina and Galería sites. The authors proposed for Galería an age of 450 ka (thousands of years ago) for the units lower GIII and GII, suggesting that the human occupation there is younger than the hominid remains of Sima de los Huesos (>530 ka) around 1 km away. In this paper, we present new results obtained by combined Electron Spin Resonance/Uranium-series (ESR/U-series) dating on 20 herbivorous teeth from different levels at the Galería site. They are in agreement with the TL results for the upper part of the stratigraphic sequence (GIV and GIIIb), in the range of between 200 and 250 ka. But for the GIIIa to GIIb levels, the TL ages become abruptly older by 200 ka while ESR ages remain relatively constant. Finally, the TL and ESR data agree in the lowest part of the section (GIIa); both fall in the range of around 350-450 ka. Our results suggest a different interpretation for the GII, GIII and GIV units of Galería and the upper part of Gran Dolina (TD10 and TD11) than obtained by TL. The ESR/U-series results are supported by a Bayesian analysis, which allows a better integration between stratigraphic information and radiometric data. PMID:23830175

  8. Cronograma de amostragem de alface cultivada em hidroponia para ajuste de curvas de crescimento vegetativo Sampling chronology of hydroponics lettuce plants for adjusting vegetative growth curves

    Directory of Open Access Journals (Sweden)

    Sidinei José Lopes

    2007-10-01

    Full Text Available O objetivo deste trabalho foi determinar o cronograma de amostragem de plantas de alface hidropônica, para ajuste de curvas de crescimento durante o período vegetativo. Foram realizados dois cultivos de alface, variedade Regina, de 8/9/2004 a 19/11/2004 (primavera/verão e 22/2/2005 a 24/5/2005 (verão/outono, em estufas de plástico do Dep. de Fitotecnia, da UFSM, Santa Maria, RS. A partir do ajuste do modelo co-seno com amostragem diária, registrada como padrão, diferentes intervalos entre as amostragens foram simulados para o ajuste do mesmo modelo. A fim de se encontrar o intervalo adequado, foi comparada a variância de falta de ajuste do modelo de amostragem diária com as variâncias de falta de ajuste dos modelos com diferentes intervalos de amostragens pelo teste F. Os cronogramas de amostragens para ajuste de curvas de crescimento de plantas de alface sob hidroponia, para experimentos de primavera/verão e verão/outono, possuem intervalos iguais a dois dias, para fitomassa seca total da planta e da folha; intervalos de quatro dias, para fitomassa de raiz; e, diariamente, para área foliar.The objective of this work was to determinate a sampling chronology to adjust lettuce hidroponic growth curves during its vegetative development. The variety Regina was grown from September 8, 2004 until November 19, 2004 (spring/summer and February 22, 2005 until May 24, 2005 (summer/fall. Plants were placed inside a plastic covered greenhouse in Santa Maria, RS, Brazil. Based on the adjusted cosine model, daily samples were taken as standard and different sampling intervals were simulated in order to better adjust the same model. To estimate de adequate sampling interval a comparison was conducted between the variance of lack of adjustment of the daily sampling with the variance of lack of adjustment of different samplings intervals using an F test. Sampling chronograms for adjusting crop growth curves of hydroponics lettuce plants for both

  9. NASA/DOD Aerospace Knowledge Diffusion Research Project. Report 11: Chronology of selected literature, reports, policy instruments, and significant events affecting Federal Scientific and Technical Information (STI) in the United States

    Science.gov (United States)

    Pinelli, Thomas E.; Henderson, Madeline; Bishop, Ann P.; Doty, Philip

    1992-01-01

    The chronology is a comprehensive bibliography. It contains 512 entries covering a variety of selected literature, reports, policy instruments, and significant events affecting Federal Scientific and Technical Information (STI) from 1945 to 1990. It includes some publications and events of historic interest which relate to the evaluation of aerospace and aerospace knowledge diffusion. Each entry has been given an item number and items are arranged by columns. To provide an overview of Federal STI developments, the entries are generally arranged by date of publication and event.

  10. REVISANDO LA CRONOLOGÍA EN LA FRONTERA NORTE DE MESOAMÉRICA, ESTADO DE DURANGO, MÉXICO (Reviewing the Chronology on the Northern Border of Mesoamerica, Durango, Mexico)

    OpenAIRE

    José Luis Punzo Díaz

    2016-01-01

    La cronología de la frontera norte de Mesoamérica ha sido controvertida en las últimas tres décadas, especialmente en lo referente a la cultura Chalchihuites. En este sentido, en este artículo se reanalizan las dataciones absolutas que se han hecho a lo largo de 60 años de trabajos arqueológicos y se presentan los últimos hallazgos realizados recientemente en el estado de Durango, abonando con esto el establecimiento de un cronología definitiva en esta región. ENGLISH: The chronology of the n...

  11. Landscape change on the SE Australian Tablelands in the Holocene: an updated chronology of gully incision and 'post-settlement' alluviation

    Science.gov (United States)

    Portenga, Eric W.; Bishop, Paul; Gore, Damian B.; Westaway, Kira E.

    2014-05-01

    -profile at each site is a regional phenomenon. We demonstrate that changes in grain-size and mineralogy alone cannot explain the observed jump in the luminescence signal at the swampy meadow-PSA boundary, and we therefore suggest that we are observing a change in environmental conditions that prevents sediment from being fully bleached in transport before reburial as PSA. Two burial-age OSL samples were collected at six suitable sites: the first at the base of each PSA deposit and the second at the top of the underlying swampy meadow sediment. We determined burial-ages from these 12 samples using a single grain OSL methodology and calculated the burial age of PSA deposits using a minimum age model. These new data aid in our investigation of intrinsic and extrinsic factors that may have triggered gully incision at each of our sites and, in conjunction with existing data, illustrate a detailed regional chronology for Tablelands evolution over the last few centuries.

  12. 210Pb-226Ra chronology reveals rapid growth rate of Madrepora oculata and Lophelia pertusa on world's largest cold-water coral reef

    Directory of Open Access Journals (Sweden)

    N. Tisnérat-Laborde

    2011-12-01

    Full Text Available Here we show the use of the 210Pb-226Ra excess method to determine the growth rate of corals from one of the world's largest known cold-water coral reef, the Røst Reef off Norway. Two large branching framework-forming cold-water coral specimens, one Lophelia pertusa and one Madrepora oculata were collected alive at 350 m water depth from the Røst Reef at ~67° N and ~9° E. Pb and Ra isotopes were measured along the major growth axis of both specimens using low level alpha and gamma spectrometry and the corals trace element compositions were studied using ICP-QMS. Due to the different chemical behaviors of Pb and Ra in the marine environment, 210Pb and 226Ra were not incorporated the same way into the aragonite skeleton of those two cold-water corals. Thus to assess of the growth rates of both specimens we have here taken in consideration the exponential decrease of initially incorporated 210Pb as well as the ingrowth of 210Pb from the decay of 226Ra. Moreover a~post-depositional 210Pb incorporation is found in relation to the Mn-Fe coatings that could not be entirely removed from the oldest parts of the skeletons. The 226Ra activities in both corals were fairly constant, then assuming constant uptake of 210Pb through time the 210Pb-226Ra chronology can be applied to calculate linear growth rate. The 45.5 cm long branch of M. oculata reveals an age of 31 yr and a~linear growth rate of 14.4 ± 1.1 mm yr−1, i.e. 2.6 polyps per year. However, a correction regarding a remaining post-depositional Mn-Fe oxide coating is needed for the base of the specimen. The corrected age tend to confirm the radiocarbon derived basal age of 40 yr (using 14C bomb peak with a mean growth rate of 2 polyps yr−1. This rate is similar to the one obtained in Aquaria experiments under optimal growth conditions. For the 80 cm-long specimen of L. pertusa a remaining contamination of metal-oxides is observed for the middle and basal part of the coral skeleton, inhibiting

  13. A multi-proxy record from the Quaternary Vienna Basin: Chronology, climate and environmental change at the Alpine-Carpathian transition during the last 250,000 years

    Science.gov (United States)

    Salcher, Bernhard; Lomax, Johanna; Frank, Christa; Preusser, Frank; Scholger, Robert; Ottner, Franz; Wagreich, Michael

    2016-04-01

    assemblages giving us the opportunity to reconstruct changes to the paleoenvironment, well compensating for the typically lack of pollen in such environments. For example high species diversity in land-snail assemblages associated with a large quantity of xeric individuals in overbank fines point to narrow riparian habitats along distinct streams. They are limited by dry grasslands were soil forming processes dominate. This is in accordance with the lithofacies data suggesting changes to the river style and transport mode but is also in accordance with the Holocene record. Compared to modern data, land-snails assemblages suggest that the mean annual precipitation was generally lower during most of the covered time period. Similar is true for the estimated mean annual temperature: Only during the late MIS7, malacological data suggests temperatures which may have been slightly higher than today. To our knowledge, the provided chronologies of the land-snail successions do also reflect the first absolute age constraints from assemblages clearly older than the LGM.

  14. Arithmetical Average Trap in Financial Ratio Analysis and Chronological Average Placement%财务比率分析中算术平均数陷阱与序时平均数的置入

    Institute of Scientific and Technical Information of China (English)

    陈益云

    2011-01-01

    Based on the analysis of all the traps in financial ratios by using simple arithmetic average,we propose that it should be necessary to introduce chronological average to overcome the defect of the simple arithmetic average that is liable to the influence of extreme values and describes the phenomenon only from a static perspective.Three indicators of the inventory turnover,accounts receivable turnover ratio and return on net assets are used to prove that chronological average can not only dynamically reflect business situation of enterprises but also provide relevant and reliable financial information.%在分析财务比率中因使用简单算术平均数而出现的种种陷阱的基础上,指出了为克服简单算术平均数易受个别或少数极端值影响和只从静态上说明总体水平的缺陷,有必要引入序时平均数,并以存货周转率、应收账款周转率和净资产收益率三个比率进行计算分析说明序时平均数能从动态上反映企业的经营状况,能更好地为企业相关者提供可靠的财务信息。

  15. REVISANDO LA CRONOLOGÍA EN LA FRONTERA NORTE DE MESOAMÉRICA, ESTADO DE DURANGO, MÉXICO (Reviewing the Chronology on the Northern Border of Mesoamerica, Durango, Mexico

    Directory of Open Access Journals (Sweden)

    José Luis Punzo Díaz

    2016-03-01

    Full Text Available La cronología de la frontera norte de Mesoamérica ha sido controvertida en las últimas tres décadas, especialmente en lo referente a la cultura Chalchihuites. En este sentido, en este artículo se reanalizan las dataciones absolutas que se han hecho a lo largo de 60 años de trabajos arqueológicos y se presentan los últimos hallazgos realizados recientemente en el estado de Durango, abonando con esto el establecimiento de un cronología definitiva en esta región. ENGLISH: The chronology of the northern frontier of Mesoamerica has been very controversial for the last three decades, especially regarding the Chalchihuites Culture. In this sense, this article revisits the dating done in the last 60 years of archaeological investigations in the area, and presents the recent findings done in the state of Durango, contributing to set up a definitive chronology for the region.

  16. Characteristics of Tree-Ring Width Chronologies in the Middle of Altay Region and Their Responding to Climate Change%阿勒泰中部地区树轮宽度年表特征及其对气候的响应

    Institute of Scientific and Technical Information of China (English)

    海丽其姑·阿不来海提; 袁玉江; 魏文寿; 喻树龙; 张同文; 陈峰; 尚华明; 张瑞波

    2015-01-01

    利用采自阿勒泰中部地区森林中下部林缘(1354~1970 m)5个采点的西伯利亚落叶松(Larix sibirica Ledeb.)及1个采点的西伯利亚云杉(Picea obovata Ledeb)样本,建立树轮宽度年表,分析年表特征参数的气候指示意义表明:在6个年表中,拜克托别标准化树轮宽度年表的信噪比和样本对总体的代表性最大、平均敏感度较高、一阶自相关较小,表明该标准化树轮宽度年表所包含的气候信息可能最为丰富,其次是大东沟前标准化树轮宽度年表。依据年表间的互相关系数,合成了由拜克托别和大东沟前2个采点构成的区域年表BKQ以及由拜克托别、大东沟前、二道房南和贾登屿4个采点组成的区域年表BDEJ。分析6个单点年表及2个区域年表对气候的响应发现,拜克托别年表相对于其它5个单点年表及2个区域年表,在重建阿勒泰气象站6—8月降水量方面可能具有很好的应用潜力,而区域年表(BDEJ)则在重建阿勒泰气象站4—8月降水日数方面可能具有很好的应用潜力。%Six tree-ring cores of Larix sibirica Ledeb and Picea obovata Ledeb were sampled from the middle of Altay at the lower elevation of 1 354~1 970 m. Six tree-ring width chronologies were developed using standard dendrochronological methods, and the features and their climatic information were analyzed in this paper. It shows that:among all the six sampling sites,the sample representative and signal-noise ratio of the standardized chronology of BKL is the highest, with the higher mean sensitivity,smaller order autocorrelation; it shows that the standardized chronology of BKL contained possibly most climate information and that of DDQ contained the second more . According to the number of mutual relations between tree-ring width chronologies, the regional chronology of BKQ was synthesized by the two Collect points from BKL and DDQ and the regional chronology of BDEJ

  17. Comparative study of Late-Holocene glacier chronologies in the Southern Alps of New Zealand and maritime Scandinavia - potential for improvement of spatial differentiation and interpretative studies on a global scale?

    Science.gov (United States)

    Winkler, S.

    2009-04-01

    Reconstructing Holocene glacier chronologies and the related climate history helps to improve the knowledge how glaciers respond to changes of the climate. Comparative studies of Holocene glacier chronologies on a global scale offer the opportunity to assess the causes of glacier dynamics and verify the numerous hypotheses about the impact of individual climate factors. The current research project "MaMoGla" (Holocene and recent dynamics of maritime mountain glaciers) investigates the Southern Alps of New Zealand and maritime Scandinavia. It focuses on maritime mountain glaciers and their characteristics. The project should deliver a contribution towards a better spatial differentiation and decision whether there are ‘global' Holocene climate modes or not? Older Holocene glacier chronologies of the Southern Alps/New Zealand have been found as not on a comparable detailed standard as the Scandinavian counterpart. In addition, previous research has revealed the need for revision due to methodological uncertainties, e.g. the previous focus on Tasman Glacier as meanwhile disregarded key locality. A new attempt to com­bine the relative-age dating technique of the Schmidt-hammer with in situ (terrestrial) cosmogenic nuclide (10Be) surface exposure dating offered the opportunity to im­prove the New Zealand glacier chronology. Preliminary results from Strauchon Glacier, a valley glacier west of the Main Divide of the Southern Alps in Westland/Tai Poutini National Park, showed a pattern that could partially already been confirmed at neighbouring glaciers. On a large lateral moraine complex several individual moraine ridges represent three sequences, each related to one major Late-Holocene LIA (‘Little Ice Age')-type event. These three Neoglacial events predate the youngest major advance (‘Little Ice Age') and have been dated to 2,400/2,500 a BP, c. 1,700 a BP, and 1,000/1,100 a BP. The absence of any evidence of glacial activity during the Hypsithermal and first

  18. Analysis of the damage caused by natural and anthropogenic sinkholes in Italy, on the basis of a nation-wide chronological catalogue

    Science.gov (United States)

    Vennari, Carmela; Guzzetti, Fausto; Marchesini, Ivan; Parise, Mario; Salvati, Paola

    2013-04-01

    Sinkholes of both natural or anthropogenic origin are widespread phenomena in Italy, and locally constitute the main hazard. Notwithstanding the potential threat they represent to the built-up environment, sinkholes are rarely considered in the assessment of the geological hazards, and are generally underrated when compared to other hazards such as floods and landslides. Using a variety of information sources we have recently compiled a chronological catalogue of about 700 events that occurred in Italy. Mandatory for including a sinkhole in the catalogue is the knowledge of the date of occurrence. This is considered to be complete when hour/day/month/year of the event are all available, which corresponds to high accuracy of the record. When the information about time of occurrence is more limited (for instance, comprising only month and year, or a few generic information), the accuracy is considered of progressively lower degree (medium, medium-low or low). The documented sinkholes in the catalogue cover a time span from 276 B.C. to the present day. For any event the location (precise or approximate) is also included, ranked in different levels of certainty, according to the information provided by the sources or derived from our direct surveys. More than 50 % of the sinkholes in the catalogue are related to man-made cavities, excavated in different rock types, including limestones, calcarenites, and volcanic rocks. This is due to the complex history of the country, and the many phases of underground constructions that had occurred during the different epochs, with a variety of purposes (working places, rupestrian settlements, hydraulic works, quarries, worship sites, etc.). Location of these cavities often got lost in time, so that they were later on included in the expansion of newly developed towns, thus increasing the related risk. Natural sinkholes, on the other hand, are generally located in areas where soluble rocks (carbonates, evaporites) crop out, or

  19. RESEARCH HISTORY ,GLACIAL CHRONOLOGY AND ORIGINS OF QUATERNARY GLACIATIONS IN CHINA%中国第四纪冰期历史、特征及成因探讨

    Institute of Scientific and Technical Information of China (English)

    崔之久; 陈艺鑫; 张威; 周尚哲; 周力平; 张梅; 李川川

    2011-01-01

    Studies in Quaternary glaciations in China were started in the early 1900s and experienced three research stages:( 1 ) initial observation stage,( 2 ) controversy stage focusing on "Quaternary glaciers in Eastern China", and (3) innovation stage focusing on modern glaciers and Quaternary glaciations in Western China. The studies and debates significantly improved the understanding of the sequences and chronology of Quaternary glaciations and their formation, development and evolution mechanisms. In particular, most studies rejected the long-time argument of "Quaternary glaciers in Eastern China" and the hypothesis that a "unified ice-sheet on the Tibetan Plateau" had ever existed. Based on relative dating and geomorphic/geological evidence, the onset of Quaternary glaciations in China started from the Shishapangma Claciation in the late stage of Early Pleistocene. However,no absolute ages are available for this glaciation. Currently, the Wangkun Glaciation ( 0. 7 ~ 0. 5Ma) in the Middle Pleistocene dated by ESR and paleo-magnetism is widely accepted as the earliest glaciation in China. After the Wangkun Claciation, several major glacial advances were identified, including the Zhonglianggan Claciation, the Cuxiang Claciation (Penultimate Glaciation) , the Dali Glaciation( Last Glacial) and Glacial advances in Holocene. In total, six major glaciations were identified in China.The onset of Quaternary glaciations in China is significantly younger than and does not synchronize with that of polar and high-latitude regions. In particular, the local Last Glacial Maximum ( LGM) in most mountainous regions in China happened during MIS 3b, significantly older than the Last Glacial Maximum of MIS 2 in polar and high-latitude regions. The onset and development of Quaternary glaciations in China are highly dependent on the elevations of various mountainous regions, reflecting the influences of both tectonic uplift and climate change, whereas the glaciations in polar and high

  20. Nutrient budgets, marsh inundation under sea-level rise scenarios, and sediment chronologies for the Bass Harbor Marsh estuary at Acadia National Park

    Science.gov (United States)

    Huntington, Thomas G.; Culbertson, Charles W.; Fuller, Christopher C.; Glibert, Patricia; Sturtevant, Luke

    2014-01-01

    Eutrophication in the Bass Harbor Marsh estuary on Mount Desert Island, Maine, is an ongoing problem manifested by recurring annual blooms of green macroalgae species, principally Enteromorpha prolifera and Enteromorpha flexuosa, blooms that appear in the spring and summer. These blooms are unsightly and impair the otherwise natural beauty of this estuarine ecosystem. The macroalgae also threaten the integrity of the estuary and its inherent functions. The U.S. Geological Survey and Acadia National Park have collaborated for several years to better understand the factors related to this eutrophication problem with support from the U.S. Geological Survey and National Park Service Water Quality Assessment and Monitoring Program. The current study involved the collection of hydrologic and water-quality data necessary to investigate the relative contribution of nutrients from oceanic and terrestrial sources during summer 2011 and summer 2012. This report provides data on nutrient budgets for this estuary, sedimentation chronologies for the estuary and fringing marsh, and estuary bathymetry. The report also includes data, based on aerial photographs, on historical changes from 1944 to 2010 in estuary surface area and data, based on surface-elevation details, on changes in marsh area that may accompany sea-level rise. The LOADEST regression model was used to calculate nutrient loads into and out of the estuary during summer 2011 and summer 2012. During these summers, tidal inputs of ammonium to the estuary were more than seven times greater than the combined inputs in watershed runoff and precipitation. In 2011 tidal inputs of nitrate were about four times greater than watershed plus precipitation inputs, and in 2012 tidal inputs were only slightly larger than watershed plus precipitation inputs. In 2011, tidal inputs of total organic nitrogen were larger than watershed input by a factor of 1.6. By contrast, in 2012 inputs of total organic nitrogen in watershed runoff

  1. Geographic extent and chronology of the invasion of non-native lionfish (Pterois volitans [Linnaeus 1758] and P. miles [Bennett 1828]) in the Western North Atlantic and Caribbean Sea

    Science.gov (United States)

    Schofield, Pamela J.

    2009-01-01

    The Indo-Pacific lionfishes (Pterois volitans [Linnaeus 1758] and P. miles [Bennett 1828]: Family Scorpaenidae) are the first non-native marine fishes to establish in the Western North Atlantic. The chronology of the invasion is reported here using records from the US Geological Survey's Nonindigenous Aquatic Species database. Currently, lionfish are established off the Atlantic coast of the USA from the Florida Keys to Cape Hatteras (North Carolina), the Great Antilles, Bermuda, Bahamas, Cayman Islands and Turks and Caicos. The species have been reported from only one island in the Lesser Antilles (St. Croix), but it is not yet established there. Lionfish are established in Mexico, Honduras and Costa Rica. Reports have come from the Gulf of Mexico (Florida), Belize, Panama and Colombia; although lionfish are not considered established in these localities at this time (August 2009), invasion is likely imminent.

  2. REVALUACIÓN DE LA CRONOLOGÍA DE ERUPCIONES DEL VOLCÁN VESUBIO (ITALIA A PARTIR DE 79 A. D. (Reassessment of the Eruptive Chronology of Italy’s Vesuvius Volcano from AD 79 to 1906

    Directory of Open Access Journals (Sweden)

    Jaime Urrutia-Fucugauchi

    2016-03-01

    Full Text Available El volcán Vesubio se caracteriza por numerosas erupciones, separadas por periodos de baja actividad, en un área densamente poblada que incluye los centros de Pompeya y Herculano y, actualmente, Nápoles. Los estudios vulcanológicos y arqueológicos han requerido, entre otros datos y observaciones, determinar la frecuencia y la naturaleza efusiva o explosiva de las erupciones empleando técnicas de datación y la construcción de una cronología de alta resolución. En este estudio se analizan 14 flujos de eventos eruptivos en el periodo de 79 a 1906 A. D., para los cuales presentamos nuevas dataciones arqueomagnéticas usando el modelo geomagnético SHA.DIF.14k. Las direcciones paleomagnéticas de los flujos se correlacionan con la curva de variación secular, permitiendo revaluar la cronología eruptiva del Vesubio. ENGLISH: Vesuvius Volcano, located in a densely populated area including the cities of Pompeii, Herculaneum and now Naples, is characterized by numerous eruptions separated by periods of quiescence. Information on the frequency and nature of this activity is critical for both volcanological and archaeological studies. Dating techniques in tandem with historical records can provide a high resolution chronology for Vesuvius’ eruption history. In this study, we analyze paleomagnetic data from 14 lava flows dating between AD 79 to 1906 using the recently developed SHA.DIF.14k geomagnetic model. We correlate the paleomagnetic directions of the flows with a new secular variation curve, resulting in a reassessment of the eruptive chronology of Vesuvius.

  3. Detailed chronology of mid-altitude fluvial system response to changing climate and societies at the end of the Little Ice Age (Southwestern Alps and Cévennes, France)

    Science.gov (United States)

    Astrade, Laurent; Jacob-Rousseau, Nicolas; Bravard, Jean-Paul; Allignol, Françoise; Simac, L.

    2011-10-01

    Over a historical timescale, landscapes have been strongly affected by fluctuations in climate and by the impact of human societies. This study examines the historical evolution of mid-altitude fluvial systems in the Western Alps and Cévennes (SE Massif Central) in the context of marked climate and anthropogenic change at the end of the Little Ice Age (late 19th century). This work contributes to the reconstruction of river paleodynamics by investigating the nature and chronology of geomorphological changes in upper river basins. In order to produce a detailed reconstruction of hydromorphological changes, we combined two approaches: the study of historical archives and the use of bioindicators (the dating of terraces using dendrochronology and of silt benches using lichenometry in order to reconstruct the evolution of the river channels). The 19th century is a particularly propitious period for the study of surface dynamics because archives have preserved a wealth of qualitative and quantitative data concerning rivers (economic statistics, meteorological and hydrological observations, illustrative documents, descriptions by contemporary observers). It is also a period for which reliable dating methods are available for detrital deposits in rivers. The period provides new information on how the transition between the Little Ice Age and current climate conditions affected the evolution of drainage basins and stream channels by highlighting a succession of phases in the erosive process (e.g., the preparatory role of the drought of 1830-1838 in the erosion crisis of 1855-1870) and refining the chronology of events (very early onset of riverbed incision). The results highlight the effect of climate (small hydroclimatic fluctuations), amplified by strong anthropization, on the rhythm of landscape change and on the relative stabilization of the landscape at the end of the 19th century. In addition, the synchronization of phenomena on the two sides of the Rhone Valley

  4. Tree-ring Width Chronology of Populus tremula and Its Relationship with the Weather in Changbai Mountain of Northeastern China%长白山山杨年轮年表及其与气候变化的关系

    Institute of Scientific and Technical Information of China (English)

    王雨茜; 高露双; 赵秀海

    2013-01-01

    以长白山自然保护区内设立面积为1 hm2的固定样地内山杨为主要研究对象,介绍了使用RESISTOGRAPH树木针测仪获取年轮宽度的过程,并使用COFECHA对获取的年轮宽度进行的交叉定年和控制检验.结果表明,获得的山杨宽度年表轮宽指数与该地区月平均气温达到显著相关(P<0.05),生长季气温与树轮径向宽度正相关性显著,从而影响了山杨的生长,冬季低温则制约树木的生长,当年生长季前4月份的温度为树木萌发需要的积温提供基础;从山杨宽度年表轮宽指数与该地区月降水量的关系可看出,树木生长季的降水量对树木生长产生一定影响,其中上一年9月份由于降水的减少使其与树轮宽度表现出显著负相关,而秋冬季节降水量的增加可促进下一年树木径向生长.%Populus tremula in 1 hm2 fixed sample plot in the Changbai Mountain was investigated to describe the process of obtaining the width by using Rinntech RESISTOGRAPH,and test the cross dating and quality control of tree-ring measurements by COFECHA.The results indicate that the chronology index in the width of P.tremula has significant correlation with the average monthly temperature (P<0.05).In the growing season,there is a strong positive correlation between the radial growth and temperature,and the temperature can influence the growth of P.tremula.But in winter the low temperature restricts the growth,while the temperature in April provides the necessary foundation in tree growth.Based on the relationship with the chronology index of the monthly precipitation,the amount of precipitation has some effect on the tree growth in the growing season.Especially in September,there is a strong negative correlation between the precipitation and the chronology index of the width because of the little rain in the month,while the precipitation in winter can promote the width growth.

  5. Petrogenesis and U-Pb zircon chronology of felsic tuffs interbedded with turbidites (Eastern Pontides Orogenic Belt, NE Turkey): Implications for Mesozoic geodynamic evolution of the eastern Mediterranean region and accumulation rates of turbidite sequences

    Science.gov (United States)

    Eyuboglu, Yener

    2015-01-01

    The Meso-Cenozoic geodynamic evolution of the Eastern Pontides Orogenic Belt, which is one of the key areas of the Alpine-Himalayan system, is still controversial due to lack of systematic geological, geophysical, geochemical and chronological data. The prevailing interpretation is that this belt represents the southern margin of Eurasia during the Mesozoic and its geodynamic evolution is related to northward subduction of oceanic lithosphere. This paper reports the first detailed geological, geochemical and chronological data from felsic tuffs interbedded with late Cretaceous turbidites in the Southern Zone of the Eastern Pontides Orogenic Belt. Individual tuff layers are thin, mostly shards and 10-20% broken quartz crystals, whereas the crystal-rich tuffs consist of > 50% crystals. The zircon U-Pb data show three statistically distinct ages at 84, 81 and 77 Ma, with uncertainties of about 1 Ma, suggesting that tuff-forming late Cretaceous magmatism started about 84 Ma ago and was episodically active over a minimum of 7 Ma. The age data also indicate that the average accumulation rate of the turbiditic sequence that hosts the felsic tuffs remained constant between 36 and 40 cm/10 ky. Their enrichment in LIL and LRE elements relative to HFS and HRE elements, and also strongly negative Nb, Ta and Ti anomalies, are consistent with those of magmas generated by subduction-related processes. The tuffs have relatively low initial ratios of 143Nd/144Nd (0.512296-0.512484; εNd: - 2.1 and - 7.2) and 87Sr/86Sr (0.704896-0.706159). Their initial Pb isotopic compositions range from 18.604 to 18.646 for 206Pb/204Pb, from 15.644 to 15.654 for 207Pb/206Pb and from 38.712 to 38.763 for 208Pb/204Pb. The distribution of Sr-Nd isotopic compositions in the late Cretaceous igneous rocks from different locations of the Eastern Pontides Orogenic Belt is consistent with two-component mixing between depleted mantle and crust. However, the Pb isotopic data are not compatible with two

  6. Succession and simultaneity in a big settlement: chronology of the macro-village of Marroquíes Bajos (Jaén, Spain. c 2500-2000 cal BC

    Directory of Open Access Journals (Sweden)

    Zafra de la Torre, Narciso

    2003-12-01

    Full Text Available The example of the large site of Marroquíes Bajos is used to discuss the efficiency of typological and radiocarbon chronologies in measuring socio-economic changes in the archaeological record. The concept of simultaneity is examined, along with the relativity and the uncertainty of interpretations. This problem can be resolved by assuming the existence of ranges of simultaneity and accepting the consequences of the current nature of archaeological reality. It is necessary to make the nature of archaeological time an object of disciplinary study.

    Poniendo como ejemplo la fechación del sistema hidrológico de la macro-aldea de Marroquíes Bajos, se debate la eficacia de las cronometrías tipológicas y radiocarbónicas en su relación con el tiempo del proceso, que asocia los cambios en el registro a los cambios socio-económicos. Para ello se examina el concepto de simultaneidad observando que introduce la relatividad y la incertidumbre en las interpretaciones. Este problema puede superarse asumiendo la existencia de escalas de simultaneidad y aceptando las consecuencias del carácter actual de toda realidad arqueológica. Se concluye con la necesidad de hacer de la naturaleza del tiempo arqueológico un objeto de estudio de la disciplina.

  7. Chronology of the Holocene loess-paleosol section and its deposition and pedogenesis on the south of Chinese Loess Plateau%黄土高原南部全新世古土壤的沉积序列

    Institute of Scientific and Technical Information of China (English)

    贾耀锋; 黄春长; 庞奖励; 牛俊杰

    2008-01-01

    Optically stimulated luminescence (OSL) dating for polymineral fine-grained loess samples, collected in Laoguantai (LGT) section on the south of the Chinese Loess Plateau,was made by application of single-aliquot regenerative-dose (SAR) protocol. A 'Double-SAR'procedure in which aliquots are subjected to both infrared (IR) and blue stimulations was used,and two sets of equivalent dose (Ds) determinations were produced and assumed to rela tepredominantly to feldspathic and quartz fine grain populations respectively. The OSL ages estimated from IRSL signals are smaller than those estimated from [post-IR] OSL signals due to the anomalous fading of feldspar IR signals, based on fading experiment. The young ages of the samples near ground surface may be originated from the post-depositlonal disturbance by the intensifying humanity's cultivation since 3.0 ka BP in the Guanzhong Basin, south of the Chinese Loess Plateau. Based on OSL dating, as well as field observations and stratlgraphic correlation, we determine the chronology of the LGT Ioess-paleosol sequence. In combination with climate proxy records, It is indicated that aeolian loess deposition and pedogenesis underwent polyphase changes during the Holocene, likely to have been driven by shifts in the East Asian monsoon. This suggests that aeolian loess deposition is episodic and highly variable, with contributions from non-aeolian processes such as alluvial deposition found in the area.

  8. Date identification of the Zhouji materials during the period of King Xin--The chronology Solving method of oracle boneS and bronzes in the Shang and Zhou dynasties

    Institute of Scientific and Technical Information of China (English)

    李勇

    2002-01-01

    By identifying the dates of the Zhouji materials (one kind of oracle bone) during the period of King Xin (also called Zhou the last monarch in Shang Dynasty), this paper establishes a new "Direct Solving Method" (DSM) to solve the chronology problems in the Shang and Zhou dynasties. The mathematical models are more suitable for those materials with the Ganzhi (the Heavenly Stems and Earthly Branches, the Chinese ancient date recorded method being of the 60-day cycle, that the repetitive cycle is independent of any astronomical parameter, each day within this cycle has its own name and can also be expressed by the numbers from l to 60) record of the date, lunar month, and their year intervals and all of them are in history documents, oracle bones and bronze vessels. For example, taking the 12 Zhouji materials in the period of King Xin,we derive the two best results of the first year when Xin assumed the reins of government in probably 1063 BC or 1052 BC.

  9. 额尔齐斯河上游西伯利亚云杉树轮宽度年表特征分析及其对气候的响应%Analyses of Tree-Ring Width Chronologies of Picea obovata Ledeb in the Upper Stream Section of the Irtysh River and Tree-Growth Response to Climate

    Institute of Scientific and Technical Information of China (English)

    姜盛夏; 袁玉江; 喻树龙; 张同文; 陈峰; 尚华明; 张瑞波; 崔宇

    2015-01-01

    利用采自阿尔泰山南坡额尔齐斯河上游森林6个采样点的低海拔西伯利亚云杉(Picea obovata Ledeb)树轮样本,建立6个树轮宽度指数年表。分析标准化树轮宽度年表的特征参数及对气候的响应发现:(1)可可托海北(KKT)年表包含的气候信息最多,其次是塔里德萨依(TLD)年表。(2)区域年表(HEC)与富蕴气象站上年7月到当年6月降水量相关最高达0.755,该研究结果与新疆天山山区云杉对气候的响应完全一致。降水是森林下限西伯利亚云杉树轮宽度生长的主要限制因子。(3)海拔相对较高的协特克阔依汗(XTK)和KKT年表除与其它年表具有对降水相同的响应特点外,还与当年8月的平均最低气温呈显著正相关。(4)区域年表树轮宽度指数过去292 a来经历了9个偏高时段和8个偏低时段,揭示了该地区降水的长期变化。%The study area is located in the mountainous area of the upper stream section of the Irtysh River on the south slope of Altai Mountains. Following standard dendrochronological procedures, six tree-ring width chronologies were developed from Picea obovata Ledeb trees at the lower elevation ranging from 1 130 m to 1 700 m. The results show that the KKT chronology may contain most climatic signals among six chronologies. And the amount of climatic signals of TLD chronology is the second. The correlations between six tree-ring width chronologies and the precipitation of per -growth season and growth season are positive. After testing different combinations of months, higher correlation coefficients between tree-ring width indices and precipitation were found for the period from July the previous year to June of the current year (r=0.755). Our results showing the influence of precipitation on tree-ring growth in the study area are similar to those of dendroclimatic studies in the Tien Shan Mountains. The precipitation during July-June is a

  10. Setting in evidence of the new climatic tendency in Algeria by the analysis of the main variables of the climate : Survey of the chronological sets on more of 50 years.

    Science.gov (United States)

    Zeineddine, N.

    2009-09-01

    Setting in evidence of the new climatic tendency in Algeria by the analysis of the main variables of the climate : Survey of the chronological sets on more of 50 years. In the present conditions of the global climatic changes, North Africa and Maghreb, observe these last years of the distresses without precedent. This new tendency expresses itself by a rise of the temperatures confirmed in several countries. In the same way to this rise, one also notes an intensification of the climatic cycles (more and more humid humid periods, more and more dry dry periods). So, after the long droughts observed in the years four - twenty and ninety, the a lot more humid period bootjack is noted in the whole region. These phases are punctuated however sometimes of stern droughts, that been the case in 2000 to Morocco and in Algeria. The humid phases are as for them more and more frequent and are characterized henceforth by very intense rainy episodes. Repeatedly, serious floodings touched these countries. In 2002 in Algeria, it is the capital that has been touched, the districts of Bab - El Wadi was heavily damaged. In the valley of the Soummam, the town of Bejaïa was the theater of important phenomena of urban flooding in 2007. In the Algerian Sahara, heavy rains provoked the rise in the water level of the wadi M' Zab and the submersion of the city of Ghardaïa. All as Algeria, Tunisia has also been touched by these phenomena. The city of Tunis knew a tragic episode thus in 2007. To the west extreme of North Africa in 2002, Morocco has been hit by important floodings that made 35 deaths.. Progressively, the climatic conditions become unusual. The signs of the changes prove to be even more meaningful with the records of rain for the agricultural year 2008 / 2009 in the under region from the Maghreb (Morocco - Algeria). Qualified of exceptional and historic, rains have generously supplied the watertables, carrying the water security margin to close to two years in drinking water

  11. 宋南渡文学编年系地研究的构想%Conception of Chronology and Location of the Literature in Southern Migration of Song Dynasty

    Institute of Scientific and Technical Information of China (English)

    李欣

    2016-01-01

    为了对宋南渡文坛予以整体观照,有必要对宋南渡文学进行编年系地研究。具体表现在先考索作家的生平事迹和活动地理环境,考订作品的创作时间和创作地点;再依据作家作品的活动地理开展创作作品的时地关系研究,动态考察文学创作与地理空间的关系;最后进行“时段文学史”研究,对宋南渡文学史上具有影响力的年度文学特征、文学的演变规律等问题进行理论探讨。%In order to give a holistic view on the literature in southern migration of Song Dynasty, it is necessary to study the chronology and location of it. Firstly, it should study the writer's life events and activities in the geographical environment and creation time and location. Secondly, it should study the relationship between the time and place of the works and between the literary creation and location according to the activities space of the writer’s works. Finally, it should study the time literature history in southern migration of Song Dynasty of the annual literary characteristics and literary evolution law theory and so on.

  12. From Suns to Life: A Chronological Approach to the History of Life on Earth 7. Ancient Fossil Record and Early Evolution (ca. 3.8 to 0.5 Ga)

    Science.gov (United States)

    López-Garcia, Purificacón; Moreira, David; Douzery, Emmanuel; Forterre, Patrick; van Zuilen, Mark; Claeys, Philippe; Prieur, Daniel

    2006-06-01

    Once life appeared, it evolved and diversified. From primitive living entities, an evolutionary path of unknown duration, likely paralleled by the extinction of unsuccessful attempts, led to a last common ancestor that was endowed with the basic properties of all cells. From it, cellular organisms derived in a relative order, chronology and manner that are not yet completely settled. Early life evolution was accompanied by metabolic diversification, i.e. by the development of carbon and energy metabolic pathways that differed from the first, not yet clearly identified, metabolic strategies used. When did the different evolutionary transitions take place? The answer is difficult, since hot controversies have been raised in recent years concerning the reliability of the oldest life traces, regardless of their morphological, isotopic or organic nature, and there are also many competing hypotheses for the evolution of the eukaryotic cell. As a result, there is a need to delimit hypotheses from solid facts and to apply a critical analysis of contrasting data. Hopefully, methodological improvement and the increase of data, including fossil signatures and genomic information, will help reconstructing a better picture of life evolution in early times as well as to, perhaps, date some of the major evolutionary transitions. There are already some certitudes. Modern eukaryotes evolved after bacteria, since their mitochondria derived from ancient bacterial endosymbionts. Once prokaryotes and unicellular eukaryotes had colonized terrestrial ecosystems for millions of years, the first pluricellular animals appeared and radiated, thus inaugurating the Cambrian. The following sections constitute a collection of independent articles providing a general overview of these aspects.

  13. 闵尔昌《江子屏先生年谱》校点二种正误%Correction to the Emendations and Punctuations of a Chronological Life of Mr. Jiang Ting by Min Erchang

    Institute of Scientific and Technical Information of China (English)

    高明峰

    2012-01-01

    A Chronological Life of Mr. Jiang Ziping by 1VAn Erchang is important in the study of Jiang Fan and even the academy in Qing dynasty, which has been collated by Qi Yongxiang, and also by Zheng Xiaoxia and Wu Ping. Qi's revision has 29 errors, including 14 word-missings, 6 abundant words, 8 word faults, 1 inverted mistake, as well as 8 punctuation errors, including 5 period and comma mistakes and 3 wrong marks. The version by Zheng X aoxia and Wu Ping have the following two problems: the wrong note format and punctuation errors.%闵尔昌《江子屏先生年谱》是研究江藩乃至清代学术的重要资料。漆永祥和郑晓霞、吴平分别对其进行了校点整理。漆永祥校点本存在文字错误共有29处,含脱误14处,衍误6处,讹误8处,倒误1处。另有标点错误8处,含句逗不当5处,专名线标示不当3处。郑晓霞、吴平标点本存在闵尔昌《江子屏先生年谱》注文标识不当以及标点失误两大问题。

  14. Chronological ageing of human hair keratin fibres.

    Science.gov (United States)

    Thibaut, S; de Becker, E; Bernard, B A; Huart, M; Fiat, F; Baghdadli, N; Luengo, G S; Leroy, F; Angevin, P; Kermoal, A M; Muller, S; Peron, M; Provot, G; Kravtchenko, S; Saint-Léger, D; Desbois, G; Gauchet, L; Nowbuth, K; Galliano, A; Kempf, J Y; Silberzan, I

    2010-12-01

    Examination of very long hair (length > 2.4 m) using a large range of evaluation methods including physical, chemical, biochemical and microscopic techniques has enabled to attain a detailed understanding of natural ageing of human hair keratin fibres. Scrutinizing hair that has undergone little or no oxidative aggression--because of the absence of action of chemical agents such as bleaching or dyeing--from the root to the tip shows the deterioration process, which gradually takes place from the outside to the inside of the hair shaft: first, a progressive abrasion of the cuticle, whilst the cortex structure remains unaltered, is evidenced along a length of roughly 1 m onwards together with constant shine, hydrophobicity and friction characteristics. Further along the fibre, a significant damage to cuticle scales occurs, which correlates well with ceramides and 18-Methyl Eicosanoic Acid (18-MEA) decline, and progressive decrease in keratin-associated protein content. Most physical descriptors of mechanical and optical properties decay significantly. This detailed description of natural ageing of human hair fibres by a fine analysis of hair components and physical parameters in relationship with cosmetic characteristics provides a time-dependent 'damage scale' of human hair, which may help in designing new targeted hair care formulations. PMID:20384898

  15. Chronology of the Frozen Dumpling Issue

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    January 30:Japan informed China that some consumers in Tokushima prefecture got food poisoning after they ate frozen dumplings produced by Hebei Tianyang Food Company.According to the Japanese,the food inspection test results showed traces of the pesticides dichlorvos and methamidophos in frozen dumpling samples.

  16. Sino-African Relations:A Chronology

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Despite the geographical distance that separates them, China and Africa cherish a relationship lasting over 2,000 years. According to historical records, China had contacts with Africa as earty as the third century B.C. In the Han Dynasty (206 B.C.-A.D. 220). Exchanges became frequent In the Tang Dynasty (618-907) and Song Dynasty (960-1279). In the Ming Dynasty (1368-1644), Chinese navigator Zheng He traveled to what Is now Somalia and Kenya on the east African

  17. Reconstructing the Chronology of Supernovae: Determining Major Variations in the History of the Cosmic-ray Flux Incident on the Earth's Surface by Measuring the Concentration of 22Ne in Halite

    Science.gov (United States)

    Nahill, N. D.; Giegengack, R.; Lande, K.; Omar, G.

    2008-12-01

    We plan to measure the inventory of cosmogenically produced 22Ne atoms preserved in the mineral lattice of halite in deposits of rock salt, and to use that inventory to measure variations in the cosmic-ray flux to enable us to reconstruct the history of supernovae. Bedded rock salt consists almost entirely of the mineral halite (NaCl). Any neon trapped in the halite crystals during precipitation is primarily 20Ne, with a 22Ne concentration of 9% or less. Any neon resulting from cosmic-ray interactions with 23Na is solely 22Ne; therefore, 22Ne atoms in excess of 9% of the total neon are cosmogenic in origin. Measurement of the 22Ne inventory in halite from deposits covering a range of geologic ages may enable us to document the systematic growth of 22Ne through geologic time and, thus, establish the cosmic-ray flux and a chronology of supernovae. The cosmic-ray flux is attenuated in direct proportion to the mass of material overlying a halite deposit. To adjust the 22Ne inventory to account for that attenuation, we must reconstruct the post-depositional history of accumulation and removal of superjacent sediment for each halite deposit we study. As an example of our procedure, we reconstruct here the shielding history of the Permian halite deposit, the Salado Formation, Delaware Basin, New Mexico. The stratigraphy of the Delaware Basin has been well documented via exploration and production wells drilled in search of oil and gas, exploration boreholes associated with potash mining, and comprehensive geologic site assessment of the DOE Waste Isolation Pilot Plant (WIPP). WIPP is a subsurface repository for the permanent disposal of transuranic wastes, located in southeastern New Mexico, 42 km east of Carlsbad and approximately 655 m beneath the surface in the Salado Fm. The Salado Fm is part of the Late Permian Ochoan Series, and consists of 1) a lower member, 2) the McNutt Potash Zone, and 3) an upper member. WIPP lies between marker bed (MB)139 and MB136 in the

  18. Characteristics of Tree-Ring Width Chronologies in Altay and Their Response to Climate Change%阿尔泰山区两种树轮宽度年表气候响应特征

    Institute of Scientific and Technical Information of China (English)

    牛军强; 袁玉江; 张同文; 尚华明; 张瑞波; 喻树龙; 陈峰; 姜盛夏

    2016-01-01

    The Altay Mountains are the optimum region for dendroclimatological research. In the region, few researches were conducted on the climate response difference of Larix Sibirica and Picea ob ov ata Ledeb at different elevations in the Altay Mountains. In the paper, we established the tree-ring width chronologies of Larix Sibirica and Picea obovata Ledeb for the different elevations and analyzed their response to climate. The results showed that, ①the limited climatic factor of tree ring radial growth is different at different elevations. In June temperature is the dominant factor of tree ring width of Larix Sibirica at the upper treeline and annual precipitation (from last July to current June)or spring precipitation (April to June)is the dominant factor to tree ring width of Picea ob ov ata Ledeb from the middle to lower treeline. ②From the middle to lower treeline, the response of Picea obovata Ledeb to precipitation is better than Larix Sibrica. ③The responses of tree ring width to climate of Larix Sibrica at different elevations are different. There is significant positive correlation (P<0.001)between June temperature and tree ring width of Larix Sibrica at the upper treeline. From the lower to middle treeline, there is no evidently limited factor of the tree ring width of Larix Sibrica.%阿尔泰山是树轮气候研究的理想区域,但此前关于阿尔泰山不同海拔高度西伯利亚落叶松和西伯利亚云杉树轮宽度气候响应差异的对比研究较少。本文利用阿尔泰山上树线西伯利亚落叶松以及森林中下部西伯利亚云杉和西伯利亚落叶松树轮宽度资料,在建立宽度年表的基础上,分析阿尔泰山南坡不同海拔高度不同树种对气候响应的差异。研究结果表明:①上树线与森林中下部区域树轮宽度生长的气候限制因子不同,上树线落叶松树轮宽度生长的气候限制因子为6月平均温度,森林中下部云杉树轮生长的气候

  19. 冀东马兰庄条带状硅铁建造的变质时代及地质意义%Metamorphic chronology of the BIF in Malanzhuang of eastern HebeiProvince and its geological implications

    Institute of Scientific and Technical Information of China (English)

    李延河; 张增杰; 伍家善; 尚龙平

    2011-01-01

    The Precambrian Banded Iron Formations (BIF) are the most important iron resource both in China and abroad, whether in the exploratory reserves or in the quantity of the exploitation. BIF were also the special geo-chemical sediments in the early earth history which recorded the composition and the redoxomorphic stage of the contemporary atmosphere and the ocean as well as their evolution. The paleo-weathering crust of BIF, which is the most enriched iron ore, is widely distributed in the world. However, this type of BIF has never been found in China. Why is the paleo-weathering crust of BIF absent in China? This is the main focus of this paper. The authors investigated the metamorphic chronology of the BIF in Malanzhuang by means of SHRIPMP II analysis of the zircons from the granitic rocks which occur in the interlayer of the BIF. Based on a comparative study ofthe time of the BIF formation, the authors have concluded that the BIF in China were deeply buried immediately after their formation, and subsequently they experienced regional metamorphism and migmatization. The BIF in China experienced no weathering for a long time at the earth' s surface, which is the reason why the paleo-weathering crust type of enriched iron ore cannot be found in China.%前寒武纪条带状硅铁建造(BIF)是世界,也是中国最重要的铁矿资源类型,无论是储量,还是开采量,均居首位.前寒武纪条带状硅铁建造是地球早期特有的化学沉积建造类型,广泛分布于太古代—早元古代(3.2~1.8 Ga),记录了地球早期大气和海洋的化学成分、氧化还原状态及演化,是广大地质工作者长期关注的焦点之一.在国外,与BIF有关的古风化壳型富铁矿广泛发育,同时也是国外重点开采的富铁矿类型,但在中国一直没有发现.本文测定了冀东迁安矿区东矿带马兰庄硅铁建造中与硅铁建造互层产出的花岗质岩石的锆石SHRIMP U-Pb年龄,确定了BIF遭受混合岩化的时代,

  20. 科尔沁沙地1826年以来榆树树轮宽度年表的建立及降水重建%ESTABLISHMENT OF RING WIDTH CHRONOLOGY AND RAINFALL RECONSTRUCTION OF Ulmus pumila L.IN HORQIN SANDY LAND SINCE 1826

    Institute of Scientific and Technical Information of China (English)

    马龙; 刘廷玺; 冀鸿兰; 罗艳云; 段利民; 杨颖

    2011-01-01

    利用10个采样点230个树木年轮样本,通过树轮分析程序,建立了科尔沁沙地区域1826~2008年共计183年长度的榆树树轮宽度年表.通过分析发现,水热条件与科尔沁沙地榆树生长关系密切.以标准年表及年表t+1年和t+2年序列重建了区域1826~2006年年降水.从过去181年来看,年降水重建序列具有2年、12年、18年和30年等变化准周期,分别经历了5个偏湿和5个偏干阶段,干旱和偏干年份分别占总年份的0.55%和16.02%,1950~2006年间偏干年数占1900~2006年间偏干总年数的78.57%,偏干阶段年数不断增加.降水出现了4次突变,1839年和1920年前后均发生了由少到多的突变,1861年和1958年前后均发生了由多到少的突变,这其中尤以1958年前后突变最为显著.总体上,科尔沁沙地近181年中,1826~1957年近130年间降水变化较为平缓,而后近50年,降水量趋于减少,气候趋于干旱.%The current study was done on Ulmus pumila L. in Horqin sandy land (42°36' ~ 45°20'N, 117°45' ~124°06'E). Samples were collected according to the principles of ecological environment, perception and restoration. Two hundred and thirty U. pumila L. tree ring samples were collected using the tree growth cones from 10 sites ( KLDD , MLML, KLSS , HQHST, ZZMLQ, KLWD. XAHY , ZQBGTL, KLMX. and BLYYC ) in 2009. The pretreatment and dating were carried out according to the analytical procedure for tree rings. The widths of U. pumila L. tree rings were measured and the cross-dating was performed through the COFECHA procedure. The U. pumila L. growth trend was fitted to a negative exponential function or spline calculated using the ARSTAN procedure ( the time step was assumed as 50 years) . The growth trend of U. pumila L. rings was removed , and all samples were used to establish a regional and comprehensive width chronology. The standard.residual,and self-regression chronologies of 183 years ( 1826 to 2008) were obtained. The

  1. Non - chronological writing: newspaper article%Non - chronological writing: newspaper article

    Institute of Scientific and Technical Information of China (English)

    刘琼

    2012-01-01

    1 Students plant trees and learn about the environment. 2 A cab driver went to the girl' s rescue as she was hurt. 3 The basketball match between Class 1 and Class 3 will take place on Monday, September 23.%【写前储备】 新闻报道常用语

  2. 西藏舍索矽卡岩型铜多金属矿床年代学与地球化学特征及意义%Chronology, geochemical characteristics and the significance of Shesuo copper polymetallic deposit, Tibet

    Institute of Scientific and Technical Information of China (English)

    赵元艺; 崔玉斌; 吕立娜; 石登华

    2011-01-01

    舍索矿床位于西藏申扎县北部,属班公湖-怒江成矿带中段,为小型矽卡岩型铜多金属矿床.本文在野外地质调查和室内岩矿鉴定基础上开展了锆石LA-ICP-MS U-Pb法测年、主量与微量元素测试、H-O、C、S和Pb同位素、流体包裹体拉曼光谱、包裹体温度与盐度分析.矿区成矿岩体花岗闪长岩年龄为116Ma,A/CNK值在1.0附近,A/NK值在1.62~1.88之间,为准铝质与过铝质的过渡类型.微量元素蛛网图中,富集大离子不相容元素Rb、Th、Pb、Ti,贫Nb.稀土配分模式属于右倾型,重稀土部分的曲线形态平缓,∑REE=89.89×10-6 ~97.92×10-6,∑LREE/∑HREE =7.47 ~9.31,δEu=0.75~0.89,具有不明显的负Eu异常.矿床形成于班公湖-怒汪洋向南(即冈底斯地块)俯冲碰撞闭合之前的岛弧环境.石英包裹体流体主要为岩浆水.方解石的δ13 Cv-PDB(‰)=-3.6~-2.0:δ34SV-CDT(‰)=-10.3~2.7,以负值为主,出现-8.5‰与-3.5‰两个峰值,辉钼矿的δ34S出现较大的负值.花岗闪长岩的锶钕同位素显示其源区为幔源,在上升过程中受到下地壳物质的影响.包裹体均为气液两相包裹体,气相成分主要为CO2,有少量的N2与CH4.气液比(%)为5~45,大小为3×6~33×20μm.测试的均一温度范围为130 ~ 290℃,主要介于180~260℃,盐度主要介于3% ~6% NaCleqv和10% ~ 18% NaCleqv,总体显示为低温低盐度特点.成矿物质由岩浆与地层共同提供.%Shesuo deposit is located in the north of Shenzha county, Tibet It is near the Bangong Lake-Nujiang metallogenic belt, and a small skarn type copper-richen polymetallic deposit This paper is based on the systemic Held geological survey, indoor rock and ore appraisal, zircon LA-ICP-MS U-Pb dating, test of major and trace element, H-O, C, S and Pb isotopes, Raman spectra, temperature and salinity of fluid inclusions, and find out its chronology and geochemical characteristics. The age of granodiorites which is

  3. Cronología cerámica en Cancuén: historia de una ciudad del Clásico Tardío Ceramic Chronology at Cancuén: a History of a Late Classic Period City

    Directory of Open Access Journals (Sweden)

    Mélanie Forné

    2011-01-01

    Full Text Available El sitio arqueológico Cancuén se destaca en el área maya del Clásico Tardío por su localización en el río de la Pasión, entre las Tierras Altas y las Tierras Bajas de Guatemala; desde allí la ciudad controló parte del flujo de bienes entre ambas áreas. Esto pudo comprobarse a través de la excavación de un taller de manufactura de artefactos de jade, cuya existencia fue un hecho único en las ciudades de Tierras Bajas. El estudio de la cerámica de este sitio presenta un doble reto: primero, ubicar Cancuén culturalmente, revelando una mezcla de influencias cerámicas procedentes de varias regiones vecinas. Una presentación sintética de la tipología permite vislumbrar la complejidad de las redes de intercambio y producción local de las vasijas. El segundo reto es el de establecer una cronología fina para los apenas 150 años de duración de la ocupación del sitio. La confrontación de la tipología cerámica con los datos epigráficos y los eventos políticos locales, permite establecer una secuencia cronológica completa, una de las primeras para esta zona fronteriza entre Tierras Bajas y Tierras Altas.Cancuén archaeological site is relevant within the Late Classic Maya context because of its geographical position on Pasión River, between Lowlands and Highlands of Guatemala, from where it controlled one of the greatest trade route between both areas. This has been evidenced by the excavation of a workshop where jade artifacts where produced, which is a unique discovery in Maya Lowlands. The analysis of ceramics in Cancuén represents a double challenge: first, it may define Cancuén's culturally, highlighting a mix of ceramic influences coming from different neighboring regions. A rapid presentation of the typology shows a quite complex panorama for exchange and local production of vessels. The second challenge is about establishing a fine chronology for the only 150 years of occupation. By confronting ceramic data with

  4. A Restatement on the Chronology Order of the Jin Marquises Cemetery in Tianma-Qu Village and Also the Early Capital of the Jin%再论天马-曲村晋侯墓地的墓主年代序列——兼论晋国早期的都城变迁问题

    Institute of Scientific and Technical Information of China (English)

    贾洪波

    2012-01-01

    The arrangement of the chronology of the Jin marquises cemetery should be from the Marquis Wu to Marquis Zhao according to Tianma-Qu Village marquises of the cemetery in accordance with the records of descent corresponding sequence of Jin marquises in Shiji·Jin Shijia.Jin,Yi and Jiang are three different capitals of Jin.Jin located in today's the Tianma-Qu Village,and Yi may be ruins in Gucheng village,Jiang is likely around the site of Weigou-Beishoucheng.%按照天马-曲村晋侯墓地晋侯诸墓与《史记.晋世家》晋侯世系对应的年代序列,其排列应为武侯至昭侯。晋、翼、绛是三个不同的晋都地点,晋在今天马-曲村遗址,翼可能在今故城村遗址,绛可能在今苇沟—北寿城遗址一带。

  5. Study on the relation between the degree of dental calcification and chronological age about Chinese Han nationality aged 6~18 years old groups of the female gender%中国汉族6~18周岁女性人群牙齿生长发育的年龄研究

    Institute of Scientific and Technical Information of China (English)

    田雪梅; 封华; 董迎春; 谭宇; 王晓明; 王昊; 韩冰; 庹琳; 王坚; 张继宗

    2011-01-01

    Objective This study was to explore the relation between degree of dental calcification and age in Chinese Han nationality adolescents and youths of the female gender, then to set up equations for estimating age by tooth.Methods The samples consisted of 6 923 pieces of digital orthopantomograms belonging to the groups aged 6 ~ 18 years old,accordance to the standard for grading the degree of dental calcification,the observers graded the low mandibular dental calcification degree showing in the samples, then dealt the data with SPSS 13.0 and set up the regression equations for estimating age;finally, a blind test was carried out based on 181 samples not used in the study.Results There was a perfect relation between chronological age and each tooth( r > 0.6 ), there were no significant statistic differences (P > 0.05 ) in the low mandibular dental calcification degree between homonymic teeth and there was a good correlation between them (r >0.93) ;the regression model used in the research was rational and the mean error between the estimated age and chronological age is 0.421 ± 0.272 year.Conclusion The methods used in this study shows a favorable foreground in estimating age for Chinese Han nationality groups aged 6 ~ 18 years old of the female gender in forensic practice.%目的 研究牙齿钙化程度与年龄的关系,建立利用牙齿推断中国汉族女性人群年龄的方程.方法 通过对6 923名6~18周岁汉族女性儿童及青少年全口曲面断层影像下领恒牙的钙化程度进行评分;将分级值及其对应的年龄输入SPSS软件进行分析,最终建立推断年龄的方程模型;从研究样本外随机抽取已知年龄的样本181例进行盲测.结果 牙齿钙化评分值与年龄相关分析结果相关系数r均大于0.6,同名牙评分值侧别间统计分析结果P>0.05且相关系数r均大于0.93,方程拟合优度检验R2=0.789,估计值标准误为1.28岁,盲测结果与真实年龄的平均误差为0.421±0

  6. Study on the relation between the degree of dental calcification and chronological age about Chinese Han nationality 6~18 years old male groups%中国汉族6~18周岁男性牙齿生长发育的年龄研究

    Institute of Scientific and Technical Information of China (English)

    田雪梅; 封华; 董迎春; 谭宇; 王晓明; 王昊; 韩冰; 庹琳; 王坚; 张继宗

    2011-01-01

    Objective This study was to explore the relation between degree of dental calcification and age on Chinese Han nationality adolescents and youths, then to set up equations for estimating age by digital orthopantomogram.Methods In accordance with the standard for grading the degree of dental calcification, the observer graded the degree of low mandibular dental calcification showing in digital orthopantomogram samples selected from 6 568 objects age range 6 ~18 years old,then dealt the figures with SPSS 13.0,in the end,established the regression equations for estimating age; besides, a blind test was done based on 160 pieces of digital orthopantomogram.Results There were no significant statistic differences in the low mandibular dental calcification degree between homonymic teeth, the nonparametric correlations between chronological age and dental calcification were above 0.7, the mean error between estimated age and chronological age was 0.423 ± 0.269 year.Conclusion The method set up in this study was reliable and would play an important role in estimating age for Chinese Han nationality adolescents and youths aged 6 ~ 18 years old in forensic science for male.%目的 研究牙齿钙化程度与年龄的关系,建立利用牙齿钙化程度推断中国汉族6~18周岁男性年龄的方程.方法 通过对6 568名6~18周岁汉族男性全口曲面断层影像上牙齿的钙化程度进行评分;将分级值及其对应年龄输入SPSS软件进行分析,建立推断年龄的方程模型;从研究样本外随机抽取已知年龄的样本160例进行盲测.结果 同名牙齿钙化评分值侧别间秩合检验结果P>0.05;下颌左侧恒牙钙化评分值与年龄相关分析结果r值均在0.7以上,下颌同名牙间相关系数r均在0.9以上;所建回归模型拟合优度R2=0.828,估计值标准误为1.23岁;盲测平均误差为0.423±0.269岁.结论 本研究所建立的方法准确可靠,可用于中国汉族6~18周岁男性人群的年龄推断.

  7. The Loess Chronology of the Island of Susak, Croatia

    Directory of Open Access Journals (Sweden)

    Lara Wacha

    2011-06-01

    Full Text Available Zahlreiche infrarot optisch stimulierte Lumineszenz (IRSL- und Radiokohlenstoff (14C-Datierungen wurden an mächtigen Löss-/Paläobodenabfolgen der Insel Susak in der nördlichen Adria von Kroatien durchgeführt. Die Datierungsergebnisse zeigen, dass eine sehr detaillierte spätpleistozäne Sedimentabfolge auf Susak erhalten geblieben ist, die mit den marinen Sauerstoffisotopenstadien (OIS 5 bis 2 korreliert. Hervorzuheben ist ein besonders mächtiges und gut gegliedertes Mittelpleniglazial. Aufgrund der großen Mächtigkeit von bis zu 90 m bildet der Löss auf Susak ein einzigartiges außerordentlich hoch aufgelöstes Klimaarchiv in dieser Region. Die zahlreichen im Löss zwischen geschalteten Paläoböden weisen auf Klimavariationen, die auf Susak wärmer gewesen sind als beispielsweise im benachbarten Karpatenbecken. Die große Mächtigkeit der Abfolge korreliert mit den während des OIS 3 allgemein höheren Staubakkumulationen in Europa. Basierend auf den nummerischen Altern kann die Löss-/Paläobodenabfolge aus Susak mit denen aus Norditalien und dem Karpatenbecken verglichen werden und ermöglichen eine detailliertere zeit-basierte Rekonstruktion der Klima- und Umweltveränderungen im Arbeitsgebiet.

  8. Functional innovations of three chronological mesohexaploid Brassica rapa genomes

    OpenAIRE

    Kim, Jungeun; Lee, Jeongyeo; Choi, Jae-Pil; Park, Inkyu; Yang, Kyungbong; Kim, Min Keun; Lee, Young Han; Nou, Ill-Sup; Kim, Dae-Soo; Min, Sung Ran; Park, Sang Un; Kim, HyeRan

    2014-01-01

    Background The Brassicaceae family is an exemplary model for studying plant polyploidy. The Brassicaceae knowledge-base includes the well-annotated Arabidopsis thaliana reference sequence; well-established evidence for three rounds of whole genome duplication (WGD); and the conservation of genomic structure, with 24 conserved genomic blocks (GBs). The recently released Brassica rapa draft genome provides an ideal opportunity to update our knowledge of the conserved genomic structures in Brass...

  9. Dental and Skeletal Maturity- A Biological Indicator of Chronologic Age

    OpenAIRE

    Rai, Vivek; Saha, Sonali; Yadav, Gunjan; Tripathi, Abhay Mani; Grover, Kavita

    2014-01-01

    Introduction: Precise evaluation of the developmental stage of a child is not only an integral part of both diagnosis and treatment of paediatric patients; it is also essential in Forensic Medicine and Dentistry. Physiologic age can be estimated by somatic, sexual, skeletal and dental maturity.

  10. A new chronology for the end-Triassic mass extinction

    Science.gov (United States)

    Deenen, M. H. L.; Ruhl, M.; Bonis, N. R.; Krijgsman, W.; Kuerschner, W. M.; Reitsma, M.; van Bergen, M. J.

    2010-03-01

    The transition from the Triassic to Jurassic Period, initiating the 'Age of the dinosaurs', approximately 200 Ma, is marked by a profound mass extinction with more than 50% genus loss in both marine and continental realms. This event closely coincides with a period of extensive volcanism in the Central Atlantic Magmatic Province (CAMP) associated with the initial break-up of Pangaea but a causal relationship is still debated. The Triassic-Jurassic (T-J) boundary is recently proposed in the marine record at the first occurrence datum of Jurassic ammonites, post-dating the extinction interval that concurs with two distinct perturbations in the carbon isotope record. The continental record shows a major palynological turnover together with a prominent change in tetrapod taxa, but a direct link to the marine events is still equivocal. Here we develop an accurate chronostratigraphic framework for the T-J boundary interval and establish detailed trans-Atlantic and marine-continental correlations by integrating astrochronology, paleomagnetism, basalt geochemistry and geobiology. We show that the oldest CAMP basalts are diachronous by 20 kyr across the Atlantic Ocean, and that these two volcanic pulses coincide with the end-Triassic extinction interval in the marine realm. Our results support the hypotheses of Phanerozoic mass extinctions resulting from emplacement of Large Igneous Provinces (LIPs) and provide crucial time constraints for numerical modelling of Triassic-Jurassic climate change and global carbon-cycle perturbations.

  11. The Chronology of Asteroid Accretion, Differentiation, and Secondary Mineralization

    Science.gov (United States)

    Nyquist, L. E.; Kleine, T.; Shih, C.-Y.; Reese, Y. D.

    2008-01-01

    We evaluate initial (Al-26/Al-27)(sub I), (Mn-53/Mn-55)(sub I), (Hf-182/Hf-180)(sub I), and Pb-207/Pb-206 ages for igneous differentiated meteorites and chondrules from ordinary chondrites for consistency with radioactive decay of the parent nuclides within a common, closed isotopic system, i.e., the early solar nebula. We find that the relative abundances of Al-26, Mn-53, and Hf-182, here denoted by I(Al)(sub CAI, I(Mn)(sub CAI) and I(Hf)(sub CAI), are consistent with decay from common initial values for the bulk solar system. I(Mn)(sub CAI) and I(Hf)(sub CAI) = 9.1+/-1.7 x 10(exp -6) and 1.06+/-0.09 x 10(exp -6) respectively, correspond to the canonical value of I(Al)(sub CAI) = 5.1 x 10(exp -5). I(Hf)(sub CAI) thus determined is consistent with I(Hf)(sub CAI) = 1.003+/-0.045 x 10(exp -6) directly determined in separate work. I(Mn)(sub CAI) is within error of the lowest value directly determined for CAI. We suggest that erratically higher values directly determined for CAI in carbonaceous chondrites reflect proton irradiation of unaccreted CAIs by the early Sun after other asteroids destined for melting by Al-26 decay had already accreted. The Mn-53 incorporated within such asteroids would have been shielded from further "local" spallogenic contributions. The relative abundances of the short-lived nuclides are less consistent with the Pb-207/Pb-206 ages of the corresponding materials with the best consistency being obtained between (Hf-182/Hf-180)(sub I) and Pb-207/Pb-206 ages of angrites. (Hf-182/Hf-180)(sub I) decreases with decreasing Pb-207/Pb-206 ages at the rate expected from the 8.90+/-0.09 Ma half-life of Hf-182. However, the model "CAI age" thus determined, T(sub CAI,Mn-W) = 4568.6+/-0.7 Ma, is older than the commonly accepted directly measured value T(sub CAI) = 4567.l+/-0.2 Ma. I(Al)(sub I), and (Mn-53/Mn-55)(sub I) are less consistent with Pb-207/Pb-206 ages, but determine T(sub CAI, Mn-Cr) = 4568.3+/-0.5 Ma relative to I(AI)(sub CAI)= 5.1 x 10(exp -5) and a Pb-207/Pb-206 age of 4558.6 Ma for the LEW86010 angrite. However. the (Mn-53/Mn-55)(sub I) and Pb-207/Pb-206 ages of "intermediate" age D'Orbigny-clan angrites and Asuka 881394 are inconsistent with radioactive decay from CAI values with a Mn-55 half-life of 3.7+/-0.4 Ma. in spite of consistency between (Mn-53/Mn-55)(sub I) and (Al-26/Al-27)(sub I). Nevertheless, it appears that the Mn-Cr method with I(Mn)(sub CAI) = 9.1+/-1.7 x 10(exp -6) can be used to date primary igneous events and also secondary mineralization on asteroid parent bodies. We summarize ages thus determined for igneous events on differentiated asteroids and for carbonate and fayalite formation on carbonaceous asteroids.

  12. Preliminary Cosmogenic Nuclide Chronology of Late Pleistocene Missoula Floods

    Science.gov (United States)

    Balbas, A.; Clark, J.; Clark, P. U.; Caffey, M. W.; Woodruff, T. E.; Baker, V. R.

    2014-12-01

    The Missoula floods had the largest known peak flood discharges of fresh water known from the geologic record. Multiple floods are believed to have originated from the failure of the Purcell trench ice lobe, which dammed glacial Lake Missoula. The flood waters traveled westward creating the Channeled Scabland region, a spectacular complex of anastomosing channels, coulees, cataracts, loess islands, rock basins, broad gravel deposits, and immense gravel bars in east-central Washington State. Several important questions about the Missoula floods and the formation of the Channeled Scabland remain, primarily due to the few geochronological constraints on their timing. Attempts to date the duration of the multiple floods have produced a wide range of ages (13-19 ka from land deposits and 13-31 ka from marine cores), but few of these directly constrain the age of the major flood landscape elements. Here we present 14 new in situ cosmogenic 10Be ages from quartz-bearing boulders deposited at four sites in eastern Washington. Wallula Gap is a narrow constriction along the Columbia River between Oregon and Washington. Hydraulic damming of floodwater at Wallula Gap created glacial Lake Lewis. Surface exposure ages on large boulders found at over 300 m elevation above the river at this site will date the largest flood events. The Wenatchee region represents the most northwestern area influenced by flooding. Dates from this area will determine when flooding occurred after the retreat of the Okanogan lobe. We sampled boulders from the lower Pangborn Bar, ice-rafted boulders north of Wenatchee, and boulders from a flood bar on the Columbia River north of Wenatchee. A boulder from the Mattawa Fan was sampled to assess the last time a megaflood came through the Sentinel Gap. Finally, in order to constrain the last debris dam failure at the southern end of the Upper Grand Coulee, we sampled flood boulders deposited on the Ephrata Fan.

  13. SERM Forest Fire Chronology of Saskatchewan in Vector Format

    Science.gov (United States)

    Naelapea, Ott; Nickeson, Jaime; Hall, Forrest G. (Editor)

    2000-01-01

    The BOReal Ecosystem-Atmosphere Study (BOREAS) staff personnel worked with several Canadian agencies to obtain various GIS data for use in the research efforts. This data set is a series of ARC/INFO export files of the fire history of Saskatchewan by year from 1945 to 1996, with a few missing years. The data set was compiled and provided by the Saskatchewan Environment and Resource Management (SERM) Wildlife Branch.

  14. Chronology, causes and progression of the Messinian salinity crisis

    NARCIS (Netherlands)

    Krijgsman, W.; Hilgen, F.J.; Raffi, I.; Sierro, F.J.; Wilsonk, D.S.

    2001-01-01

    The Messinian salinity crisis is widely regarded as one of the most dramatic episodes of oceanic change of the past 20 or so million years (refs 1±3). Earliest explanations were that extremely thick evaporites were deposited in a deep and desiccated Mediterranean basin that had been repeatedly isola

  15. Chronology, causes and progression of the Messinian salinity crisis

    OpenAIRE

    Krijgsman, W.; F. J. Hilgen; Raffi, I.; F. J. Sierro; Wilsonk, D.S.

    2001-01-01

    The Messinian salinity crisis is widely regarded as one of the most dramatic episodes of oceanic change of the past 20 or so million years (refs 1±3). Earliest explanations were that extremely thick evaporites were deposited in a deep and desiccated Mediterranean basin that had been repeatedly isolated from the Atlantic Ocean, but elucidation of the causes of the isolation--whether driven largely by glacio-eustatic or tectonic processes--have been ham pered by the absence of an accurate time ...

  16. The Chronology of the Development of Covert Speech in Children

    Science.gov (United States)

    Conrad, R.

    1971-01-01

    Results of an experiment with children ages 3-11 years performing serial recall tasks suggest that it is not until about age 5 years that children's overt speech reaches a functional stage that would justify internalization. (Author/WY)

  17. Chronology of polyphase extension in the Windermere Hills, northeast Nevada

    Science.gov (United States)

    Mueller, K.J.; Cerveny, P.K.; Perkins, M.E.; Snee, L.W.

    1999-01-01

    Fission-track and 40Ar/39Ar dating and chemical correlation of volcanic strata exposed in the Windermere Hills and northern Pequop Mountains, northeast Nevada, indicate a protracted, polyphase history of Tertiary (late Eocene-late Miocene) extension along the northern margin of a major Cordilleran metamorphic core complex. Early extension is recorded by a west-tilted half graben filled with early Oligocene (34.79 ?? 0.18-39.18 ?? 0.12 Ma) sedimentary rocks in the eastern Windermere Hills above the low-angle Black Mountain detachment fault. The early Oligocene half graben conformably overlies a widespread suite of late Eocene (39.18 ?? 0.12-40.38 ?? 0.06 Ma) calc-alkaline volcanic rocks, reflecting a temporal link between early extension at a high structural level and the end of the ignimbrite flare-up. These strata are cut by east-west-striking normal faults, which are exposed along, and parallel to, the northern margin of the metamorphic complex. Available age data (e.g., between 14.93 ?? 0.08 and 34.79 ?? 0.18 Ma) permit the interpretation that the east-west-striking faults formed at the same time as, or after, large-magnitude unroofing of high-grade rocks. We interpret the east-west-striking faults to accommodate differential uplift of greenschist-grade metamorphic rocks in the upper crust, above a lateral ramp in a west-northwest-directed mylonitic shear zone. Subsequent extension in the Windermere Hills is defined by deep, rapidly filled half grabens of middle Miocene (<7.42 ?? 2.0 to 14.93 ?? 0.08 Ma) age that unconformably overlie older faults and synextensional deposits. These are the youngest half grabens in the region and are inferred to be initiated by extensional stresses imparted to the base of the lithosphere by a laterally spreading mantle plume (e.g., the Yellowstone hotspot) located in southeastern Oregon at this time.

  18. The Chronology of the Levantine Middle Palaeolithic Period in Retrospect

    OpenAIRE

    Bar-Yosef, O.; Meignen, L.

    2009-01-01

    Durant les 20 dernières années, le développement de programmes de recherches interdisciplinaires au Proche-Orient, s’appuyant en particulier sur les nouvelles méthodes de datation, principalement en TL et ESR, ont considérablement changé notre perception de l’origine et des débuts de l’évolution des Hommes modernes. Les études en technologie lithique ont par ailleurs permis de nuancer les schémas « culturels » classiquement adoptés pour cette région. Cet article propose un bilan des hypothèse...

  19. Extinction chronology of the cave lion Panthera spelaea

    Science.gov (United States)

    Stuart, Anthony J.; Lister, Adrian M.

    2011-08-01

    The cave lion, Panthera spelaea, was widespread across northern Eurasia and Alaska/Yukon during the Late Pleistocene. Both morphology and DNA indicate an animal distinct from modern lions (probably at the species level) so that its disappearance in the Late Pleistocene should be treated as a true extinction. New AMS radiocarbon dates directly on cave lion from across its range, together with published dates from other studies - totalling 111 dates - indicate extinction across Eurasia in the interval ca. 14-14.5 cal ka BP, and in Alaska/Yukon about a thousand years later. It is likely that its extinction occurred directly or indirectly in response to the climatic warming that occurred ca. 14.7 cal ka BP at the onset of Greenland Interstadial 1, accompanied by a spread of shrubs and trees and reduction in open habitats. Possibly there was also a concomitant reduction in abundance of available prey, although most of its probable prey species survived substantially later. At present it is unclear whether human expansion in the Lateglacial might have played a role in cave lion extinction. Gaps in the temporal pattern of dates suggest earlier temporary contractions of range, ca. 40-35 cal ka BP in Siberia (during MIS 3) and ca. 25-20 cal ka BP in Europe (during the 'Last Glacial Maximum'), but further dates are required to corroborate these. The Holocene expansion of modern lion ( Panthera leo) into south-west Asia and south-east Europe re-occupied part of the former range of P. spelaea, but the Late Pleistocene temporal and geographical relationships of the two species are unknown.

  20. [Influence of meteorological and chronological factors in epilepsy].

    Science.gov (United States)

    Altimiras-Roset, Jacint; Brunet-Gómez, Alícia; Aragonès, Josep M; Roura-Poch, Pere

    2014-10-16

    Introduccion. Los profesionales que atienden urgencias medicas observan picos de incidencia de crisis epilepticas. Algunos pacientes epilepticos atribuyen sus crisis a cambios climaticos y estacionales. Objetivo. Analizar la relacion de variables meteorologicas, de calendario y circadianas con la aparicion de crisis epilepticas. Pacientes y metodos. Estudio retrospectivo en un centro residencial de personas con discapacidad intelectual. Resultados. Los 16 residentes estudiados presentan 855 crisis epilepticas, entre ellas 159 en picos o cumulos, a lo largo del periodo 2009-2012. El predominio de crisis encontrado en otoño y durante el cuarto trimestre del año no es significativo (p > 0,05). No hay relacion estadisticamente significativa entre la presencia de crisis epilepticas con las fases lunares y los dias de la semana. La mayoria de crisis epilepticas (87,2%) se presenta en horario diurno (p estadistica entre el numero de crisis epilepticas respecto a la presion atmosferica, la precipitacion, el grado de humedad y la temperatura media (p > 0,05). Conclusiones. Se constata la aparicion de picos o cumulos de crisis epilepticas. La presencia de estas presenta un marcado componente circadiano. La influencia en la epilepsia de los factores meteorologicos estudiados, fases lunares y estaciones del año no es significativa.

  1. Chronology and Ideology. Temporal Structuring in Israeli Historical Documentary Series

    NARCIS (Netherlands)

    Garami, Bosmat

    2013-01-01

    abstractThis paper examines two major Israeli historic-documentary television series, Pillar of Fire (POF), product of the 1970's, and Revival (RL), product of the 1990's.The series deal with the Zionist enterprise and its realization. The research applies Gerard Genette's central narratological typ

  2. A chronology of human understanding of the nitrogen cycle

    Energy Technology Data Exchange (ETDEWEB)

    Galloway, J.N.; Leach, A.M. [Environmental Sciences, University of Virginia, Charlottesville, VA 22904-4123 (United States); Bleeker, A. [Energy research Centre of the Netherlands, 1755 ZG, Petten (Netherlands); Erisman, J.W. [VU University, 1081 HV Amsterdam (Netherlands)

    2013-07-15

    Nitrogen was discovered in the eighteenth century. The following century, its importance in agriculture was documented and the basic components of its cycle were elucidated. In the twentieth century, a process to provide an inexhaustible supply of reactive N (Nr; all N species except N2) for agricultural, industrial and military uses was invented. This discovery and the extensive burning of fossil fuels meant that by the beginning of the twenty-first century, anthropogenic sources of newly created Nr were two to three times that of natural terrestrial sources. This caused a fundamental change in the nitrogen cycle; for the first time, there was the potential for enough food to sustain growing populations and changing dietary patterns. However, most Nr created by humans is lost to the environment, resulting in a cascade of negative earth systems impacts-including enhanced acid rain, smog, eutrophication, greenhouse effect and stratospheric ozone depletion, with associated impacts on human and ecosystem health. The impacts continue and will be magnified, as Nr is lost to the environment at an even greater rate. Thus, the challenge for the current century is how to optimize the uses of N while minimizing the negative impacts.

  3. Accretion chronology of the inner solar system: Isotopic constraints

    Science.gov (United States)

    Harper, C. L., Jr.; Jacobsen, S. B.

    1994-07-01

    In recent years, advances in understanding the nature of planetary accretion in the inner solar system have been made mainly by refinement of the method of a priori planetesimal coagulation modeling introduced by Safronov. Accretion timescales obtained in these models are intrinsically probabilistic, with increasing uncertainty at late times due to the heirarchical and stochastic nature of the accretion process, whereby the later stages of planet formation are expected to have been dominated by large merger (giant impact) events of unpredictable timing. Precise age determinations of the earliest episodes of planetary differentiation are desirable for constraining accretion and giant impact timescales directly. We are developing constraints based on three extinct radionuclide systems: (146)Sm-(142)Nd, (182)Hf-(182)W, and (244)Pu-Ru,Pd. Our W isotope data appear to strongly constrain the terrestrial accretion interval. Present evidence is too limited to identify the decay signature of (182)Hf in the early solar system unequivocally. Constraints on the Earth, Moon, and Mars from Nd-142/Nd-144 measurements are much more firmly established. The presence of a small but significant abundance of Sm-146 in the early solar system provides a chronometry particularly well suited for dating very early episodes of differentiation in planetary bodies. Our approach is based on the preservation of isotopic signatures in large-scale subcrustal reservoirs and is advantageous in cases where early-formed crustal samples are either unavailable or severely disturbed. In principle, the (146)Sm-(142)Nd system is ideal for dating differentiation episodes in the silicate portions of planetary bodies because other large-scale cosmochemical processes such as volatile depletion or core formation do not fractionate Sm/Nd. Large-scale merger events are expected to re-homogenize the silicate portion of the merged object and reset the isotopic clock. Consequently the age of the oldest differentiated mantle reservoir should provide a lower limit on cessation of hierarchical accretion series. A summary of the most significant Nd-142 data for the Earth, Moon and Mars is presented in isochron model age representation.

  4. AFSC/REFM: Alaskan flatfish chronology Black et al

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Annual growth increment patterns observed in the hard parts of many marine organisms are often related to factors in the physical environment, and investigators are...

  5. Station Blackout Initiated Event Chronology in LWR/HWR NPP

    Energy Technology Data Exchange (ETDEWEB)

    Park, Soo Yong; Ahn, Kwang Il [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2011-10-15

    Since the crisis at Fukushima nuclear power plants, a severe accident progression has been recognized as a very important area for an accident management and emergency planning. The purpose of this study is to investigate the comparative characteristics of a severe accident progression among the typical pressurized water reactor (PWR), boiling water reactor (BWR) and pressurized heavy water reactor (PHWR). The OPR 1000-like (ABB-CE type PWR), Peach Bottom-like (BWR/4 RCS with a MARK I Containment), and Wolsong1-like (CANDU6 type) plants are selected as reference plants of typical 1000 MWe PWR, 1140MWe BWR, and 600 MWe PHWR, respectively. The design parameters of these plants are quite different. Some of the major different design features of CANDU6 plant from other light water reactors, in terms of a severe accident, are that the plant adopts a duel primary heat transport system and has an additional amount of cooling water in the calandria vessel (calandria tank, CT) and calandria vault (CV). Another feature is that the CT is always submerged in water because the CV is flooded during normal operation. The containment (reactor building, R/B) failure pressure of the CANDU6 plant is considerably lower than that of the typical PWR or BWR4/MARK-I. The containment vessel free volume of MARK-I is much smaller than that of the PWR or CANDU6 plant. Since there is no steam generator (SG) or passive cooling system, the amount of cooling water inventory in BWR4 is relatively less than other plants. Meanwhile the minimum available time of battery power against station blackout (SBO) accident is different among plant types: six hours for BWR4 and four hours for 1000MWe PWR. Therefore, plant responses against the severe core damage scenarios like Fukushima accident are expected to be much different. By identifying plant response signatures, the appropriate correction actions can be developed as part of severe accident management. A SBO scenario, where all off-site power is lost and the diesel generators (DGs) fail, is simulated as an initiating event of severe accident sequence. The scenario has been taken as a very low frequency, but high-risk accident event. All current generation reactors are designed to cope with SBO only partially. For the simulation of SBO, all the emergency core cooling (ECC) systems, auxiliary feedwater (AFW) system except for turbine driven pump (TDP), and the containment spray are assumed to be inoperable for 1000MW PWR. All the ECC systems, moderator cooling system, end-shield cooling system (ESC), and local air coolers (LACs) are assumed to be inoperable to simulate the severe core damage case for CANDU6 plant. All the ECC systems except for high pressure cooing injection (HPCI) and reactor core isolation cooling (RCIC), reactor water cleanup, standby liquid control, low pressure cooling injection (LPCI), and core spray are assumed to be not working for BWR4/MARK1 plant. The thermal hydraulic and severe accident phenomenological analyses for the evaluation have been performed using the PWR and BWR versions of MAAP (Modular Accident Analysis Program) 4.06 for the PWR and BWR4/MARK1 plants, respectively. On the other hand, ISSAC (Integrated Severe Accident Analysis Code for the CANDU Plants) 4.02 has been used for the CANDU6 plant. The ISAAC program has been developed based on MAAP4. Therefore, most basic thermal hydraulic or radiological models of those two computer codes are similar. Only the plant specific system models are different from each other

  6. Early Mars Chronology: When did the Dynamo Really Die?

    Science.gov (United States)

    Lillis, R. J.; Stewart, S. T.; Roberts, J.; Bottke, W. F.; Manga, M.; Frey, H. V.; Kuang, W.; Robbins, S.

    2014-07-01

    Mars' dynamo is a key aspect of early Mars evolution. It likely started some time after primordial crust formation and ceased before the Utopia impact. Its total duration depends on impactor flux following accretion and the timing of the LHB.

  7. Calcretes in the Thar desert: Genesis, chronology and palaeoenvironment

    Indian Academy of Sciences (India)

    R P Dhir; S K Tandon; B K Sareen; R Ramesh; T K G Rao; A J Kailath; N Sharma

    2004-09-01

    The calcretes in the Thar desert occur in a variety of settings, including the piedmonts, sheet-wash aggraded plains; and this study adds calcretes in regolith and colluvio-alluvial plains to the group of settings in which calcretes occur in the region. Field logs, morphological details and analytical data such as petrographic, cathodoluminescence and geochemical characteristics are described along with a discussion on their implications. Sand dunes and sandy plains dating to > 20 ka have weakly developed calcretes. The better-developed calcrete horizons occur in pied- monts, interdunes or in areas that have sufficient groundwater. Deep sections in the region show phases of calcrete development in aeolian sand aggradation at ∼150, ∼100, ∼60 and 27-14 ka. The extensive sheetwash plains have mature calcretes and date to mid-Pleistocene. Our studies indicate that these calcretes represent a hybrid process, where carbonate enrichment of the originally calcareous host occurred due to periodically raised groundwaters, and its differentiation into nodules occurred under subaerial environment i.e., after recession of groundwater. Deep sections also show a stack of discrete calcretes that developed in individual aggradation episodes with hiatuses as indicated by ESR dating results. Nodules display a multiplicity of carbonate precipitation events and internal reorganization of calcitic groundmass. The process is accompanied by degradation and transformation of unstable minerals, particularly clays and with a neosynthesis of palygorskite. The ancient calcretes are dated from the beginning of the Quaternary to ∼600 ka and show more evolved morphologies marked by brecciation, dissolution, laminar growth on brecciated surfaces, pisolites and several generations of re-cementation. Mica/chlorite schists and such other rocks are particularly vulnerable to replacement by carbonate. In an extreme case, replacement of quart-zose sandstone was observed also. The presence of stretches of alluvio-colluvial plains in an area presently devoid of drainage bespeaks of occasional high-energy fluvial regime, under a semi-arid climate. The mid-Pleistocene period saw a shift towards more arid climate and this facilitated sheetwash aggradation. Finally, during the late Pleistocene, aggradation of aeolian sands indicated a progressively drier climate. However, this does not find its reflection in stable isotope data. The amount of carbonate in the form of calcretes is substantial. The present studies indicate that aeolian dust or rainwater are minor contributors to the carbonate budget. A more important source was provided by the pre-existing calcretes in the sheetwash aggraded plains and detrital carbonate in the aeolian sediments. The original source of carbonate in the region, however, remains unresolved and will need further investigations. Electron spin resonance protocols for the dating of calcretes were developed as a part of this study and the results accorded well with geological reasoning.

  8. On the chronology and topography of bacterial cell division.

    Science.gov (United States)

    Vicente, M; Palacios, P; Dopazo, A; Garrido, T; Pla, J; Aldea, M

    1991-01-01

    Gene products that play a role in the formation of cell septum should be expected to be endowed with a set of specific properties. In principle, septal proteins should be located at the cell envelope. The expression of division genes should ensure the synthesis of septal proteins at levels commensurate with the needs of cell division at different rates of cell duplication. We have results indicating that some fts genes located within the 2.5-min cluster in the Escherichia coli chromosome conform to these predictions.

  9. ANALYSIS OF FOOTH-AND-MOUTH DISEASES CARRIED OUT IN GOIÁS IN THE CHRONOLOGICAL SERIES 1977-1992 ANÁLISE DO COMPORTAMENTO DA FEBRE AFTOSA BOVINA EM GOIÁS NA SÉRIE CRONOLÓGICA 1977-1992

    Directory of Open Access Journals (Sweden)

    Valéria de Sá Jayme

    2007-09-01

    Full Text Available

    In order to analyse the behavorial evolution of foot-and-mouth disease in Goiás, from 1977 to 1992, in order to track its range of frequency and distribution, it was used morbi-mortality data, which contributed for the evaluation of incidence, attack and lethality data, with the respective tendencies. The evaluation of ways to diagnostic, the most common virus and its chronological conduct were studied too. The results in the focus number and incidence data were in decrease, Y = 333.81 - 0.38X and Y = 22.17 - 0.25X. An increased range was observed in lethality data (Y = 7.64 + 1.15X and attack (Y = 10.27 + 0.03X. The clinic diagnostic and the virus type A (57.58% were the most common data in the focus.

    KEY-WORDS: Foot-and-mouth disease; conduct.

    Para analisar a conduta da febre aftosa em Goiás de 1977 a 1992, visando a acompanhar a variação de sua freqüência e distribuição, foram utilizados indicadores de morbi-mortalidade. Para tal, elaboraram-se e analisaram-se os coeficientes de incidência, ataque e letalidades anuais com as respectivas tendências. Paralelamente, avaliaram-se os tipos de diagnóstico conduzidos, os tipos de vírus mais prevalentes e seu comportamento na série cronológica. Observou-se que o número de focos e o coeficiente de incidência apresentaram tendência negativa Y = 333,81 - 0,38X e Y = 22,17 - 0,25X, respectivamente. Comportamento crescente foi constatado para o coeficiente de letalidade (Y = 7,64 + 1,15X e ataque (Y = 10,27 + 0,03X. Verificou-se predomínio do diagnóstico clínico e maior ocorrência do vírus tipo A, isolado em 57,58% dos episódios.

    Densidade mineral óssea, função pulmonar, idade cronológica e idade de diagnóstico em crianças e adolescentes com fibrose cística Bone mineral density, pulmonary function, chronological age, and age at diagnosis in children and adolescents with cystic fibrosis

    Directory of Open Access Journals (Sweden)

    Márcio V.F. Donadio

    2013-04-01

    . First, demographic data were collected and, subsequently, patients underwent a spirometric test. All patients answered the Cystic Fibrosis Quality of Life Questionnaire (CFQ and underwent the six-minute walk test (6MWT and bone densitometry (DXA. RESULTS: A total of 25 CF patients were included, of which 56% were males. The mean age was 12.3±3.4 years; mean height was 149.2±14.4 cm; and mean weight was 44.4±13.9 kg. Most results on pulmonary function and bone mineral density (BMD were within normal limits. The mean forced expiratory volume in one second (FEV1 was 92.5±23.6 (% of predicted, mean forced vital capacity (FVC was 104.4±21.3 (% of predicted, and mean BMD z-score was 0.1±1.0. BMD was moderately correlated with FEV1 (r = 0.43, p = 0.03 and FVC (r = 0.57, p = 0.003. Regarding chronological age and age at diagnosis, a moderate and inverse correlation was also found (r = -0.55, p = 0.004 ; r = -0.57, p = 0.003, respectively. However, no significant correlations were found with the data from CFQ, 6MWT, and body mass index. CONCLUSION: Most patients had BMD within normal limits and presented a positive correlation with pulmonary function, as well as a negative correlation with chronological age and age at diagnosis.

  10. 羌塘地块南部晚白垩世火山岩离子探针测年及其对红层时代的约束%SHRIMP U-Pb Isotopic Dating of the Late Cretaceous Volcanic Rocks and Its Chronological Constraint on the Red-beds in Southern Qiangtang Block

    Institute of Scientific and Technical Information of China (English)

    吴珍汉; 吴学文; 赵珍; 陆露; 叶培盛; 张耀玲

    2014-01-01

    Although no qualified chronological data are available for the red-beds, stratigraphic systems of redbeds outcropped widely in southern Qiangtang Block have been mostly regarded as belonging to the Miocene Kangtuo Formation according to regional geological survey at a scale 1:250,000. In this study, the red beds intercalated with volcanic rocks were discovered in the field, and magmatic zircons were selected from the volcanic rocks, which were suitable for the SHRIMP U-Pb isotopic dating so as to provide isotopic ages of high resolution for volcanic eruptions and further to give constraint on geological time of the related red-beds. The SHRIMP 206Pb/238U isotopic ages of magmatic zircons are (83.3±1.3) Ma and (75.65±0.82) Ma respectively for the trachyte-andesite intercalations in red beds of northern Belog Co and the andesite overlying red-beds in northern Zagya Zangbu. These high-resolution isotopic ages not only well reveal periods of volcanic eruptions in Late Cretaceous but also provide chronological evidence for the Late Cretaceous basins of red-beds in southern Qiangtang Block. Geological time of the terrestrial red-beds outcropped widely in southern Qiangtang basin should be changed from the Miocene Kangtuo Formation to the Upper Cretaceous Abushan Formation according to the SHRIMP U-Pb isotopic dating of volcanic rocks in northern Belog Co and Zagya Zangbu. Such change is significant for the better understanding of tectonic evolution and geological preservation conditions of oil-gas systems in southern Qiangtang Block.%羌塘地块南部广泛出露陆相红层,1:25万区域地质调查将大部分红层划归为中新统康托组,但缺乏可靠的年代学依据。野外观测发现火山岩与红层之间存在喷发不整合接触关系,室内从火山岩选出很多岩浆锆石;应用离子探针U-Pb同位素测年方法精确测定岩浆锆石年龄,能够为研究火山喷发期次和红层形成时代提供重要依据。对羌塘地块南

  11. Relationship Between Climate and Tree-ring Chronology of Betula ermanii on Tree-line in North Slope of the Changbai Mountains%长白山北坡林线处岳桦年轮年表及其与气候的关系

    Institute of Scientific and Technical Information of China (English)

    王晓明; 赵秀海; 高露双; 姜庆彪

    2012-01-01

    运用相关函数及响应分析等树木年轮气候学方法,研究了长白山北坡林线处岳桦(Betula ermanii径向生长及其与气候的关系.结果表明,林线处岳桦年轮宽度年表具有较强的气候敏感性.其径向生长与上年7月和当年3月的温度显著负相关(P<0.05),与上年9月和当年7月的温度显著正相关;同时与上年6月降水量显著正相关.与季节性气候因子的响应分析表明,岳桦径向生长与当年春季(1~3月)和当年生长季前(4、5月)的平均温度呈显著负相关,与当年生长季前的平均最高温度显著正相关,与降水量的相关关系不显著.利用多元逐步回归方法模拟了岳桦年轮宽度指数与气候因子间的关系,并据此预测在温度和降水增加的背景下,林线处岳桦径向生长将降低14.8%.%The tree-ring width chronologies were developed in north slope of the Changbai Mountains to analyze the Betula ermanii radial growth-climate relationships through dendrochronological methods including correlation and response analysis. The results showed that the radial growth of Betula ermanii exhibited a significantly nagative correlation with monthly temperature of both previous July and current March (P < 0.05), a significantly positive correlation with monthly temperature of previous September and current July, and a significantly positive correlation with monthly total precipitation of previous June. Besides, the analysis of response toseasonally climatic factors showed that the tree-ring growth of B. Ermanii had a significantly negative correlation with mean temperature of current spring (January to March), a significantly negative correlation with mean temperature of the period before current growth season (April and May), and a significantly positive correlation with mean maximum temperature of the period before current growth season. But it showed no significant correlation with seasonally precipitation. Furthermore, the

  12. Evolução do perfil neuromotor e capacidade funcional de mulheres fisicamente ativas de acordo com a idade cronológica Evolución del perfil neuromotor y la capacidad funcional de mujeres fisicamente activas de acuerdo con la edad cronológica Evolution of neuromotor profile and functional capacity of physically active women according to chronological age

    Directory of Open Access Journals (Sweden)

    Sandra Mahecha Matsudo

    2003-11-01

    é comparar la evolución del perfil neuromotor y la capacidad funcional de mujeres activas en el período de un año de acuerdo con la edad cronológica. MÉTODOS: La muestra estuvo compuesta por 117 mujeres de 50 a 79 años de edad (: 65 ± 6,6 años participantes de un programa de ejercicios aeróbicos, dos veces por semana, 50 minutos por sesión durante 5,4 ± 3,0 años y divididas por la edad: 50-59 (n: 23; 60-69 (n: 60; 70-79 (n: 34. Los tests neuromotores y de movilidad incluyeron: fuerza muscular de los miembros inferiores y superiores, agilidad, flexibilidad de tronco, velocidad de levantarse de la silla, equilíbrio estático, velocidad normal de andar y velocidad máxima de andar. Los resultados iniciales de las dos evaluaciones siguientes, realizadas intérvalos de 6 meses, fueron comparados usando ANOVA two way, con post-hoc Bonferroni. RESULTADOS: En un ano no hubo ninguna alteración del desempeño neuromotor, ya que la velocidad de levantar de la silla y la velocidad de andar no evidenciaron diferencias significativas en los grupos de 50-59 e 60-69 años, presentando resultados un 10-20% mejores; en cuanto a la velocidad máxima de andar hubo una mejora (8% en los grupos de 60 a 79 años. CONCLUSIÓN: La evolución de la aptitud física y la capacidad funcional tuvo un comportamiento similar, en mujeres físicamente activas independientemente de la edad cronológica. Esta evolución fortalece la hipótesis de un efecto favorable de la actividad física regular en la promoción de la salud, estrategia fundamental del envejecimiento saludable.BACKGROUND AND PURPOSE: There are few longitudinal studies to determine the effect of aging on physical fitness and functional capacity of physically active women. The purpose of this study was to compare the evolution of neuromotor profile and functional capacity in active elderly women in one-year period as related to chronological age at the base line. METHODS: Sample consisted of 117 women from 50 to 79 years of age

  13. Cronologia da normatização das demonstrações contábeis no Brasil: do Código Comercial Brasileiro de 1850 ao pronunciamento 26 do CPC de 2009 = Chronology of standardization of financial statements in Brazil: Brazilian Commercial Code of 1850 to the statement of CPC 26, 2009

    Directory of Open Access Journals (Sweden)

    Paulo Schmidt

    2012-05-01

    Full Text Available O desenvolvimento do Brasil, como nação autônoma, teve seu marco inicial após sua independência de Portugal, em 1822. Diante do cenário de nascimento e evolução da sociedade brasileira, este trabalho apresenta uma pesquisa cronológica sobre a normatização das demonstrações contábeis, especialmente focada no Balanço Patrimonial (BP. Esse estudo caracteriza-se essencialmente por ser uma pesquisa bibliográfica histórica. A primeira normatização contábil brasileira ocorreu com a publicação do 1º Código Comercial Brasileiro (CCB em 26/06/1850, através da Lei nº 556. Dez anos após o CCB, entrou em vigência a Lei nº 1.083 de 22/08/1860, conhecida como “a primeira Lei das S. A. no Brasil”. O Brasil passou a ter uma Lei das S.A. atualizada, com a publicação da Lei 2.627. Em 1976, o Brasil incorpora as tendências contábeis Norte-Americanas com a nova Lei das S.A.: Lei nº 6.404 de 15/12/1976. A primeira grande alteração dessa Lei ocorreu em 2007, com a Lei no 11.638, de 28/12/2007 a Deliberação CVM 488 de 03/10/2005, contudo, já estabelecia o início do processo de convergência para a adoção dos princípios internacionais. A partir da publicação do CPC1, seguiram-se outros que reestruturaram a Contabilidade Brasileira. Dentre esses Pronunciamentos, o CPC 26 apresenta a estrutura das demonstrações contábeis em correlação às Normas Internacionais de Contabilidade – IAS 1. Constata-se que durante esse período de mais de um século e meio, especialmente analisando-se o BP, a Contabilidade Brasileira sempre buscou um caminho de atualização e vinculação mundial.The development of Brazil, as autonomous nation, had its starting point after its independence from Portugal in 1822. Against the backdrop of birth and evolution of Brazilian society, this paper presents a chronological survey on the regulation of the financial statements, especially focused on the Balance Sheet (BP. This study is characterized

  14. Impact of Differential Diagenetic Evolution on the Chronological Tightening and Pore Evolution of Tight Sandstone Reservoirs-A Case Study from the Chang-7 Tight Turbidite Sandstone Reservoir in the Southwestern Ordos Basin%差异性成岩演化过程对储层致密化时序与孔隙演化的影响--以鄂尔多斯盆地西南部长7致密浊积砂岩储层为例

    Institute of Scientific and Technical Information of China (English)

    罗静兰; 罗晓容; 白玉彬; 罗春燕; 白雪见; 李向军; 李弛

    2016-01-01

    The diagenesis,authigenic products and diagenetic evolution process restricted by the sandstone detrital components of Upper Triassic Chang-7 turbidite sandstones from the southwester Ordos Basin were studied.Impact of the differential diagenetic evolution process on the chronological tightening,pore evolution and sandstone reservoir quality was also elucidated, based upon observation of cores, observation, identification and quantitative statistics of conventional,fluorescent and casting thin sections by vacuum impregnated with epoxy resin under microscope equipped by fluorescence system,measurement of sandstone pore and pore throat image,porosity and permeability,capillary pressure,and analysis of homogenization temperature and Laser-Raman chemical composition of fluid inclusions, combined with the previous research result of the LA-ICP-MS in-situ U-Pb dating provenance tracing from the detrital zircons in the Chang-8-Chang-6 sandstones.The results show that the Chang-7 sandstone types and their petrological components and primary reservoir capacity are controlled by provenance and parent rocks;distribution of the sandstone type and the detrital minerals shows some regulation vertically;the sandstone types and the skeleton minerals influence the diagenetic process and experience certain differential diagenetic evolution process, and finally lead to sandstones tightened chronologically,which result in heterogeneity in the pore evolution,pore structure and reservoir quality heterogeneous distribution temporally and spatially.%通过岩芯观察、常规薄片与铸体薄片显微镜下鉴定与定量统计,利用电镜扫描、图像孔喉分析、荧光分析、孔隙度与渗透率、毛细管压力测定,以及流体包裹体均一温度、激光拉曼成分测定,结合前期鄂尔多斯盆地西南缘长8—长6砂岩碎屑锆石LA-ICP-MS微区U-Pb 定年物源示踪研究成果,分析了鄂尔多斯盆地西南部上三叠统长7致密浊积砂岩

  15. Chronology of Holocene climate and vegetation changes and their connection to cultural dynamics in Southern Siberia

    NARCIS (Netherlands)

    V.G. Dirksen; B. van Geel; M.A. Koulkova; G.I. Zaitseva; A.A. Sementsov; E.M. Scott; G.T. Cook; J. van der Plicht; L.M. Lebedeva; N.D. Bourova; N.A. Bokovenko

    2007-01-01

    Two sediment sequences from Big Kyzykul Lake and the Shushenskoe paleolake in the Minusinsk depression, Southern Siberia, were studied by pollen, microfossil, and geochemical analyses, as well as radiocarbon dating. The records indicate the persistence of an arid period between ~11.7-7.6 cal kyr BP,

  16. Chronology of holocene climate and vegetation changes and their connection to cultural dynamics in Southern Siberia

    NARCIS (Netherlands)

    Dirksen, V. G.; van Geel, B.; Koulkova, M. A.; Zaitseva, G. I.; Sementsov, A. A.; Scott, E. M.; Cook, G. T.; van der Plicht, J.; Lebedeva, L. M.; Bourova, N. D.; Bokovenko, N. A.

    2007-01-01

    Two sediment sequences from Big Kyzykul Lake and the Shushenskoe paleolake in the Minusinsk depression, Southern Siberia, were studied by pollen, microfossil, and geochemical analyses, as well as radiocarbon dating. The records indicate the persistence of an and period between similar to 11.7-7.6 ca

  17. Chronology of the beryllium replacement shutdown at the High Flux Isotope Reactor (HFIR), 1983

    International Nuclear Information System (INIS)

    In addition to the permanent beryllium reflector, several other components were replaced. The outer shroud and lower tracks were replaced. The new control rod access plugs and the upper tracks were installed. Replacement of collimator tubes for HB-1 and -2 are tentatively slated for the next permanent beryllium changeout. Inspection of the reactor vessel, the vessel-to-nozzle welds, core support structure, and vessel internal cladding showed them to be in acceptable condition. The highest, accumulative radiation doses received by Reactor Operations personnel during the shutdown, in mrem, were 665, 606, and 560; the highest for P and E personnel were 520, 505, and 475

  18. Human Gastric Mucosal Hydrophobicity Does dot Decrease with Helicobacter Pylori Infection or Chronological Age

    Directory of Open Access Journals (Sweden)

    Mohammed S Al-Marhoon

    2005-01-01

    Full Text Available BACKGROUND AND AIMS: Infection with cytotoxin-associated gene A (cagA Helicobacter pylori is associated with severe gastric diseases. Previous studies in humans have reported a decreased gastric hydrophobicity with H pylori infection. The aim of the present study was to differentiate between the effect of cagA+ and cagA- strains on gastric mucus hydrophobicity.

  19. Chronological and geochemical studies of granite and enclave in Baimashan pluton, Hunan, South China

    Institute of Scientific and Technical Information of China (English)

    CHEN; WeiFeng; CHEN; PeiRong; HUANG; HongYe; DING; Xing; SUN; Tao

    2007-01-01

    Zircon LA-ICP-MS U-Pb dating reveals that the Baimashan Pluton is composed mainly of late Indosinian (204.5±2.8 Ma-209.2±3.8 Ma) biotite granodiorites/monzonitic granites (LIGs) and early Yanshanian (176.7±1.7 Ma) two-micas monzonitic granites (EYGs),and the coeval (203.2±4.5 Ma-205.1±3.9 Ma) mafic microgranular enclaves (MMEs) are generally found in the former.In addition,the ages of cores within zircons from LIGs and MMEs ranging from 221.4±4.0 Ma to 226.5±4.1Ma provide evidence of multistage magma intrusion during Indosinian in the study area.Measured 3010±20.6 Ma of inherited zircon age suggests that there may be recycling Archaean curstal material in existence in this area.LIGs and EYGs share some similar geochemical features: subalkaline and peraluminous granites,enrichment of Th,U,K,Ta,Zr,Hf and LREE but depletion of Ba,Nb,P,Ti and Eu,low εNd(t) values but high (87Sr/86Sr)i ratios,and old T2DM (ca.1.9-2.0 Ga).The behaviors of incompatible elements and REE are mainly dominated by fractional crystallization of plagioclase,K-feldspar,ilmenite and apatite,but that of Sr isotope mainly controlled by EC-AFC.They are crust-sourced and derived from partial melting of paleo-Proterozoic metagreywackes and related to biotite dehydration melting.LIGs are formed in post-collisional tectonic setting as crustal local extension and thinning during late Indosinian.But EYGs may be evolved products of congeneric granitic magma with LIGs formed in late Indoinian,which were emplaced again when crust underwent extensive thinning and extension in post-orogenic tectonic setting during Yanshanian in SC after undergoing EC-AFC.MMEs should be cognate enclaves and derived from liquid immiscibility of host magma.

  1. The geology and chronology of the Acheulean deposits in the Mieso area (East-Central Ethiopia).

    Science.gov (United States)

    Benito-Calvo, Alfonso; Barfod, Dan N; McHenry, Lindsay J; de la Torre, Ignacio

    2014-11-01

    This paper presents the Quaternary sequence of the Mieso area of Central-East Ethiopia, located in the piedmont between the SE Ethiopian Escarpment and the Main Ethiopian Rift-Afar Rift transition sector.In this region, a piedmont alluvial plain is terraced at þ25 m above the two main fluvial courses, the Mieso and Yabdo Rivers. The piedmont sedimentary sequence is divided into three stratigraphic units separated by unconformities. Mieso Units I and II contain late Acheulean assemblages and a weakly consolidated alluvial sequence, consisting mainly of fine sediments with buried soils and, to a lesser degree, conglomerates. Palaeo-wetland areas were common in the alluvial plain, represented by patches of tufas, stromatolites and clays. At present, the piedmont alluvial surface is preserved mainly on a dark brown soil formed at the top of Unit II. Unit III corresponds to a fluvial deposit overlying Unit II, and is defined by sands, silty clays and gravels, including several Later Stone Age (LSA) occurrences. Three fine-grained tephra levels are interbedded in Unit I (tuffs TBI and TA) and II (tuff CB), and are usually spatially-constrained and reworked. Argon/argon (40Ar/39Ar) dating from tuff TA, an ash deposit preserved in a palustrine environment, yielded an age of 0.212 ± 0.016 Ma (millions of years ago). This date places thetop of Unit I in the late Middle Pleistocene, with Acheulean sites below and above tuff TA. Regional correlations tentatively place the base of Unit I around the Early-Middle Pleistocene boundary, Unit II inthe late Middle Pleistocene and within the Late Pleistocene, and the LSA occurrences of Unit III in the LatePleistoceneeHolocene.

  2. Beneficial modulation from a high-purity caviar-derived homogenate on chronological skin aging.

    Science.gov (United States)

    Marotta, Francesco; Polimeni, Ascanio; Solimene, Umberto; Lorenzetti, Aldo; Minelli, Emilio; Jain, Shalini; Rastmanesh, Reza; Sedriep, Sonia; Soresi, Vincenzo

    2012-04-01

    This study tested the activity of LD-1227, which contains a caviar-derived homogenate added with coenzyme Q(10) (CoQ(10))-selenium component (CaviarLieri(®), Lab-Dom, Switzerland), in aged human skin and its potential role on skin mitochondria function. Human dermal fibroblasts were obtained from healthy donors over 70 years old and treated with LD-1227 for 72 hr. As compared to baseline, LD-1227 caused a robust (>67%) collagen type I synthesis (pbeneficially affect mitochondrial function. PMID:22533426

  3. Late Glacial and Holocene Paleoliminology of two temperate lakes inferred from sediment organic 13C chronology

    Indian Academy of Sciences (India)

    N A Lovan; R V Krishnamurthy

    2000-03-01

    The stable carbon isotope (13C) and elemental C/N ratios in Total Organic Carbon (TOC) extracted from radiometrically dated cores from two Midwestern USA lakes were determined to investigate the factors that control these values in temperate lakes. The range of 13C values ( -26 to -32%) and C/N ratios (mean value ∼ 10.8) are typical of values reported for other temperate lake organic matter in this region. In the core from Lake Winnebago, Wisconsin, a negative correlation was seen between the TOC and 13C, which can be interpreted in terms of a re-mixing and consumption of sedimented organic carbon along with rapid equilibration throughout the water column. No correlation was seen between the TOC and 13C in the record from Ladd Lake, Ohio, implying that in this latter lake productivity alone was not a singular process controlling the isotope ratio. Here, it is suggested that equilibrium conditions are maintained such that the DIC of the water is never depleted of aqueous CO2 during high organic production and the resulting 13C of the organic carbon lacks correlation with the TOC. Further, in this lake a fine resolution analysis was carried out which indicated a possible anthropogenic influence on the isotope ratio around times when human settlement (∼ 300 yrs ago) and enhanced agricultural practices ( ∼ 80 yrs ago) were significant. The study shows that carbon isotope studies are useful in paleolimnologic investigations.

  4. Lunar basalt chronology, mantle differentiation and implications for determining the age of the Moon

    Science.gov (United States)

    Snape, Joshua F.; Nemchin, Alexander A.; Bellucci, Jeremy J.; Whitehouse, Martin J.; Tartèse, Romain; Barnes, Jessica J.; Anand, Mahesh; Crawford, Ian A.; Joy, Katherine H.

    2016-10-01

    Despite more than 40 years of studying Apollo samples, the age and early evolution of the Moon remain contentious. Following the formation of the Moon in the aftermath of a giant impact, the resulting Lunar Magma Ocean (LMO) is predicted to have generated major geochemically distinct silicate reservoirs, including the sources of lunar basalts. Samples of these basalts, therefore, provide a unique opportunity to characterize these reservoirs. However, the precise timing and extent of geochemical fractionation is poorly constrained, not least due to the difficulty in determining accurate ages and initial Pb isotopic compositions of lunar basalts. Application of an in situ ion microprobe approach to Pb isotope analysis has allowed us to obtain precise crystallization ages from six lunar basalts, typically with an uncertainty of about ± 10 Ma, as well as constrain their initial Pb-isotopic compositions. This has enabled construction of a two-stage model for the Pb-isotopic evolution of lunar silicate reservoirs, which necessitates the prolonged existence of high-μ reservoirs in order to explain the very radiogenic compositions of the samples. Further, once firm constraints on U and Pb partitioning behaviour are established, this model has the potential to help distinguish between conflicting estimates for the age of the Moon. Nonetheless, we are able to constrain the timing of a lunar mantle reservoir differentiation event at 4376 ± 18 Ma, which is consistent with that derived from the Sm-Nd and Lu-Hf isotopic systems, and is interpreted as an average estimate of the time at which the high-μ urKREEP reservoir was established and the Ferroan Anorthosite (FAN) suite was formed.

  5. Sedimentation and chronology of heavy metal pollution in Oslo harbor, Norway

    DEFF Research Database (Denmark)

    Lepland, Aivo; Andersen, Thorbjørn Joest; Lepland, Aave;

    2010-01-01

    Stratigraphic profiles of Cu, Cd and Hg in ten sediment cores from the Oslo harbor, Norway, combined with results of radiometric dating demonstrate that pollution by these metals peaked between 1940 and 1970. Dating results indicate that Hg discharges peaked between 1940 and 1950, Cd reached maxi...

  6. Disturbance of isotope systematics in meteorites during shock and thermal metamorphism and implications for shergottite chronology

    Energy Technology Data Exchange (ETDEWEB)

    Gaffney, A M; Borg, L E; Asmerom, Y

    2008-12-10

    Shock and thermal metamorphism of meteorites from differentiated bodies such as the Moon and Mars have the potential to disturb chronometric information contained in these meteorites. In order to understand the impact-related mechanisms and extent of disturbance to isochrons, we undertook experiments to shock and heat samples of 10017, a 3.6 billion year old lunar basalt. One sub-sample was shocked to 55 GPa, a second subsample was heated to 1000 C for one week, and a third sub-sample was maintained as a control sample. Of the isotope systems analyzed, the Sm-Nd system was the least disturbed by shock or heat, followed by the Rb-Sr system. Ages represented by the {sup 238}U-{sup 206}Pb isotope system were degraded by shock and destroyed with heating. In no case did either shock or heating alone result in rotated or reset isochrons that represent a spurious age. In some cases the true crystallization age of the sample was preserved, and in other cases age information was degraded or destroyed. Although our results show that neither shock nor thermal metamorphism alone can account for the discordant ages represented by different isotope systems in martian meteorites, we postulate that shock metamorphism may render a meteorite more susceptible than unshocked material to subsequent disturbance during impact-related heating or aqueous alteration on Mars or Earth. The combination of these processes may result in the disparate chronometric information preserved in some meteorites.

  7. Identification and Chronological Analysis of Genomic Signatures in Influenza A Viruses

    OpenAIRE

    Hu, Yuh-Jyh; Tu, Po-Chin; Lin, Chun-Sheng; Guo, Szu-Ting

    2014-01-01

    An increase in the availability of data on the influenza A viruses (IAV) has enabled the identification of the potential determinants of IAV host specificity using computational approaches. In this study, we proposed an alternative approach, based on the adjusted Rand index (ARI), for the evaluation of genomic signatures of IAVs and their ability to distinguish hosts they infected. Our experiments showed that the host-specific signatures identified using the ARI were more characteristic of th...

  8. Significance of specific immunoglobulin M in the chronological diagnosis of 38 cases of toxoplasmic lymphadenopathy.

    OpenAIRE

    Del Bono, V.; Canessa, A; Bruzzi, P.; Fiorelli, M A; Terragna, A.

    1989-01-01

    The persistence of immunoglobulin M (IgM) antibody to Toxoplasma gondii in sera from 38 patients after toxoplasmic lymphadenopathy was investigated by using an indirect immunofluorescence assay, a double-sandwich enzyme-linked immunosorbent assay, and an immunosorbent agglutination assay. Positive predictive values at 3 and 6 months after lymphadenopathy were, respectively, 45 and 73% for the indirect immunofluorescence assay, 25 and 45% for the double-sandwich enzyme-linked immunosorbent ass...

  9. A chronology of hurricane landfalls at Little Sippewissett Marsh, Massachusetts, USA, using optical dating

    DEFF Research Database (Denmark)

    Madsen, Anni Tindahl; Duller, G.A.T.; Donnelly, J.P.;

    2009-01-01

    Optical dating has been applied to sediments preserved in Little Sippewissett Marsh, Massachusetts, USA, which are associated with overwashing of the beach barrier during hurricane strikes on the coast. The aims were to determine the hurricane landfall frequency, and make comparisons with indepen......Optical dating has been applied to sediments preserved in Little Sippewissett Marsh, Massachusetts, USA, which are associated with overwashing of the beach barrier during hurricane strikes on the coast. The aims were to determine the hurricane landfall frequency, and make comparisons...... with independent age control and the historical record. Written sources of hurricane activity along the American east coast are only considered reliable back to the mid 19th century, but the sedimentary record is potentially much longer. Optical dating was applied to quartz grains extracted from thirteen samples...... the potential of optical dating in this setting. The hurricane record based upon optical dating extends approximately 300 years further back in time than the official National Oceanic Atmospheric Administration (NOAA) record. The localised nature of hurricane landfalls means that it will be necessary to collect...

  10. Revised stratigraphy and chronology for Homo floresiensis at Liang Bua in Indonesia

    DEFF Research Database (Denmark)

    Sutikna, Thomas; Tocheri, Matthew W; Morwood, Michael J;

    2016-01-01

    Homo floresiensis, a primitive hominin species discovered in Late Pleistocene sediments at Liang Bua (Flores, Indonesia), has generated wide interest and scientific debate. A major reason this taxon is controversial is because the H. floresiensis-bearing deposits, which include associated stone...

  11. THE DEVELOPMENT OF BOOK SCIENCE IN LITHUANIA: DIVISION INTO PERIODS AND CHRONOLOGY

    Directory of Open Access Journals (Sweden)

    Navickiene, Ausra

    2006-12-01

    Full Text Available It is possible to distinguish two main periods in the history of Lithuanian book science: the initial period of formation of the book science started at the beginning of the 19th century and ended by the first decades of the 20th century; the period of the independent, autonomous development of book science from the beginning of the 20th century till now. The first period is also known as a bibliographic period of book science, because the disciplines investigating a book were concentrated around bibliography, which was understood as a universal encyclopaedic science of book at that time. The border between the two periods is marked by a change in the book researchworks: the wide concept of bibliography stopped dominating the discourse; book science and bibliography were understood as two disciplines with specific objects of research, their own structures and methods. It is difficult to point out a specific date of this change but it is certain that it must have happened not later than in the 20s of the 20th century. Within these two periods, it is possible to distinguish a variety of factors that influenced the development of book science.In Lithuania, book science has emerged and was formed within the European model of development. Just after a decade since the first courses in book science delivered in France at the end of the 18th century, the subject of book science was included into the programme at Vilnius University and later the lectures were read. The most significant European (French and German book science works were known to the academic faculty at Vilnius University and collected in its library. They were used as a foundation to create the first works of book history and theory in Lithuania. These works disseminated widely popular theoretical concepts enriched by original research, which helped the formation of independent disciplines of book science, bibliography and history of literature.The development of the autonomous book science in Lithuania also coincided with the development in Europe where an independent discipline investigating a book and book matter emerged at the beginning of the 20th century. At that time Lithuania as earlier, book science was equal with other humanities’ disciplines, which were institutionalised and developed in different directions without adding original theoretical works. As in Russia and Poland, book science in Lithuania did not pass through the library period of book science as it happened in Germany where an innovative library science included a wide part of historical and theoretical book research issues. After the Second World War, the Soviet “fashions” in book science influenced it’s development in Lithuania most. It was not impossible to continue the work started during the years of independence and the traditional book science was not developed, the applied and historical issues were the limit. The changing Russian and European political and science situation during 60s stimulated the renaissance of book science in Lithuania. The term book science came back intothe use, the journal Knygotyra was established, monographs on different issues of book science were published and other facts evidenced this return. The process continues till now. In modernLithuania, the traditional book science is developed. It is the main concern of a recreated academic department at Vilnius University, which is actively promoting book science and organizing studiesof book science.

  12. Chronological Age, Cognitions, and Practices in European American Mothers: A Multivariate Study of Parenting

    Science.gov (United States)

    Bornstein, Marc H.; Putnick, Diane L.

    2007-01-01

    The authors studied multiple parenting cognitions and practices in European American mothers (N=262) who ranged from 15 to 47 years of age. All were 1st-time parents of 20-month-old children. Some age effects were 0; others were linear or nonlinear. Nonlinear age effects determined by spline regression showed significant associations to a "knot"…

  13. Glacial advances and ESR chronology of the Pochengzi Glaciation,Tianshan Mountains,China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The Pochengzi Glaciation is a typical glaciation in Quaternary in the Tianshan Mountains. The glacial landforms comprise several integrated end moraines, like a fan spreading from the north to the south at the mouth of the Muzhaerte River valley and on the piedmont on the southeastern slope of the Tumur Peak, the largest center of modern glaciation in the Tianshan Mountains. The landforms recorded a complex history of the ancient glacier change and contained considerable information of the glacial landscape evolution, and dating these landforms helps us understand the temporal and spatial shifts of the past cryosphere in this valley and reconstruct the paleoenvironment in this region. Electron spin resonance (ESR) dating of the glacial tills in the upper stratum from a well-exposed section, end moraines, and associated outwashes was carried out using Ge centers in quartz grains, which are sensitive to the sunlight and grinding. The results could be divided into three clusters, 13.6–25.3, 39.5–40.4 and 64.2–71.7 ka. Based on the principle of geomorphology and stratigraphy and the available paleoen- vironmental data from northwestern China, the end moraines were determined to deposit in the Last Glaciation. The landforms and the three clusters of ages demonstrate that at least three large glacial advances occurred during the Pochengzi Glaciation, which are corresponding to marine oxygen isotope stage 4 (MIS4), MIS3b and MIS2. The landforms also indicate that the gla- ciers were compound valley glacier in MIS2 and MIS3b and piedmont glacier in MIS4, and the ancient Muzhaerte glacier were 94, 95 and 99 km at their maximum extensions in these three glacial advances.

  14. Mono Lake Excursion as a Chronologic Marker in the U.S. Great Basin

    Science.gov (United States)

    Liddicoat, J. C.; Coe, R. S.; Knott, J. R.

    2008-05-01

    Nevada, Utah, and California east of the Sierra Nevada are in the Great Basin physiographic province of western North America. During periods of the Pleistocene, Lake Bonneville and Lake Lahontan covered valleys in Utah and Nevada, respectively, and other lakes such as Lake Russell in east-central California did likewise (Feth, 1964). Now dry except for its remnant, Mono Lake, Lake Russell provides an opportunity to study behavior of Earth's past magnetic field in lacustrine sediments that are exposed in natural outcrops. The sediments record at least 30,000 years of paleomagnetic secular variation (Liddicoat, 1976; Zimmerman et al., 2006) and have been of particular interest since the discovery of the Mono Lake Excursion (MLE) by Denham and Cox (1971) because the field behavior can be documented at numerous sites around Mono Lake (Liddicoat and Coe, 1979, Liddicoat, 1992; Coe and Liddicoat, 1994) and on Paoha Island in the lake. Moreover, there have been recent attempts to date the excursion (Kent et al., 2002, Benson et al., 2003) more accurately and use the age and relative field intensity in paleoclimate research (Zimmerman et al., 2006). It has been proposed that the excursion in the Mono Basin might be older than originally believed (Denham and Cox, 1971; Liddicoat and Coe, 1979) and instead be the Laschamp Excursion (LE), ~ 40,000 yrs B.P. (Guillou et al., 2004), on the basis of 14C and 40Ar/39Ar dates (Kent et al., 2002) and the relative paleointensity record (Zimmerman et al., 2006) for the excursion in the Mono Basin. On the contrary, we favor a younger age for the excursion, ~ 32,000 yrs B.P., using the relative paleointensity at the Mono and Lahontan basins and 14C dates from the Lahontan Basin (Benson et al., 2003). The age of ~ 32,000 yrs B.P. is in accord with the age (32,000-34,000 yrs B.P.) reported by Channell (2006) for the MLE at Ocean Drilling Program (ODP) Site 919 in the Irminger Basin in the North Atlantic Ocean, which contains as well an excursion lower in the core at ~ 40,000 yrs B.P. that he identifies as the LE, and by Lund et al. (2005, 2006) from a study of sediments recovered during the ODP. The paths of VGPs for the North Atlantic Ocean and the younger half of the excursion in the Mono Basin are similar in that they have a counterclockwise loop and are close to each other in the mid-Northern Hemisphere, and are different from the VGP path for the LE that is a large clockwise loop in the Southern Hemisphere (Channell, 2006; Lund et al., 2005, 2006). Our presentation will include the results of paleomagnetic research and new 14C dating at Searles Lake, CA, in the southern Great Basin where a record of paleomagnetic field behavior and paleoclimate are preserved in exposed and cored sediments (Liddicoat, 1976, Liddicoat et al., 1980; Smith et al., 1983) that span the proposed ages of the MLE and LE.

  15. A Historical Chronology of the Plight of African Americans Gaining Recognition in Engineering and Technology

    Science.gov (United States)

    Johnson, Keith V.; Watson, Elwood D.

    2005-01-01

    The Black scientist in America is historically an anomaly and currently a statistical rarity. In 1984 Blacks accounted for only 2.3%, or 90,500, of the 3,995,000 employed scientists and engineers (Kusmer, 1991) Even now, in the 21st century, Blacks were 11.3% of the labor force, but only 4.2% of natural scientists, 7.6% of math and computer…

  16. Metallogenic Chronology of Boron Deposits in the Eastern Liaoning Paleoproterozoic Rift Zone

    Institute of Scientific and Technical Information of China (English)

    LU Yuanfa; CHEN Yuchuan; LI Huaqing; XUE Chunji; CHEN Fuwen

    2005-01-01

    Lead isotopic analytic data of 30 ores gathered from the Zhuanmiao boron deposit, Wengquangou boron (iron) deposit and its Dongtaizi Ore Member constitute three isochrons, the corresponding ages of which are 1902±12 Ma,1852±9 Ma and 1917±48 Ma. Lead isotopic analyses of marble from the Xiquegou Member of the Qingchenzi orefield yield a Pb-Pb isochron age of 1844±27 Ma. 40Ar-39Ar quick neutron activation dating of phlogopites and microclines coexisting with ore minerals in the Wengquangou boron (iron) and Zhuanmiao boron deposits shows that: (1) the phlogopite from the Wengquangou has a plateau age of 1923±1.5 Ma and an isochron age of 1924±2.5 Ma; (2) the microcline from the Wengquangou has the plateau age of 1407±5.4 Ma and 220±12 Ma and an isochron age of 1403±19Ma; (3) the phlogopites from the Zhuanmiao yield a plateau age 1918±1.3 Ma and an isochron age of 1918±2.9 Ma; (4) the microclines from the Zhuanmiao yield the plateau age of 1420±16 Ma and 250±8 Ma and an isochron age of 1425±19 Ma and 269±16 Ma. These ages indicate that the eastern Liaoning area happened around 1900 Ma, an important tectonomagmatic event, which is consistent with the worldwide Mid-Proterozoic tectonomagmatic event. During this period, the Proterozoic Liaohe Group was folded and underwent strong normal metamorphism, and the (hydrothermal)sedimentary boron deposits (or source beds) formed earlier were strongly superimposed by mineralization, resulting in enrichment of boron; later regional geological processes made little contribution to the formation of the boron deposits.Lead isotopic components show that the U-Pb and Th-Pb isotopic system reached homogenization in the ores whereas only the U-Pb isotopic system reached homogenization in the marble from the Xiquegou district, which indicates that the boron deposits superimposed in the studied area endured a relatively strong process of hydrothermal migmatization during the end phase of early Proterozoic metamorphism.

  17. New chronological evidence for Yanshanian diagenetic mineralization in China's Altay orogenic belt

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Granitoids and related pegmatitic rare-metal deposits are widespread in China's Altay region, they used to be considered as Hercynian rocks and mineral deposits. Reported here are the 40Ar-39Ar ages of potassium-rich minerals (muscovite and microcline) in the Koktokay pegmatitic rare-metal orefield and whole-rock as well as quartz fluid-inclusion Rb-Sr isochron ages of granite and ores in the Shangkelan pegmatite rare-metal orefield. The ages indicate that there are Yanshanian Diagenetic Mineralization events happening in China's Altay orogenic belt and that formation of the famous Koktokay No.3 pegmatitic rare-metal deposit endured about 30 Ma of magmatic crystallization differentiation.

  18. Chronology and References of Volcanic Eruptions and Selected Unrest in the United States, 1980-2008

    Science.gov (United States)

    Diefenbach, Angela K.; Guffanti, Marianne; Ewert, John W.

    2009-01-01

    The United States ranks as one of the top countries in the world in the number of young, active volcanoes within its borders. The United States, including the Commonwealth of the Northern Mariana Islands, is home to approximately 170 geologically active (age volcanoes. As our review of the record shows, 30 of these volcanoes have erupted since 1980, many repeatedly. In addition to producing eruptions, many U.S. volcanoes exhibit periods of anomalous activity, unrest, that do not culminate in eruptions. Monitoring volcanic activity in the United States is the responsibility of the U.S. Geological Survey (USGS) Volcano Hazards Program (VHP) and is accomplished with academic, Federal, and State partners. The VHP supports five Volcano Observatories - the Alaska Volcano Observatory (AVO), Cascades Volcano Observatory (CVO), Yellowstone Volcano Observatory (YVO), Long Valley Observatory (LVO), and Hawaiian Volcano Observatory (HVO). With the exception of HVO, which was established in 1912, the U.S. Volcano Observatories have been established in the past 27 years in response to specific volcanic eruptions or sustained levels of unrest. As understanding of volcanic activity and hazards has grown over the years, so have the extent and types of monitoring networks and techniques available to detect early signs of anomalous volcanic behavior. This increased capability is providing us with a more accurate gauge of volcanic activity in the United States. The purpose of this report is to (1) document the range of volcanic activity that U.S. Volcano Observatories have dealt with, beginning with the 1980 eruption of Mount St. Helens, (2) describe some overall characteristics of the activity, and (3) serve as a quick reference to pertinent published literature on the eruptions and unrest documented in this report.

  19. Migration Chronology and Management of Waterbirds at Stillwater National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Lahontan Valley wetlands and associated Stillwater National Wildlife Refuge (NWR) play an important role in the maintenance and migration of several species of...

  20. The post-Paleozoic chronology and mechanism of 13C depletion in primary marine organic matter

    Science.gov (United States)

    Popp, B. N.; Takigiku, R.; Hayes, J. M.; Louda, J. W.; Baker, E. W.

    1989-01-01

    Carbon-isotopic compositions of geoporphyrins have been measured from marine sediments of Mesozoic and Cenozoic age in order to elucidate the timing and extent of depletion of 13C in marine primary producers. These results indicate that the difference in isotopic composition of coeval marine carbonates and marine primary photosynthate was approximately 5 to 7 permil greater during the Mesozoic and early Cenozoic than at present. In contrast to the isotopic record of marine primary producers, isotopic compositions of terrestrial organic materials have remained approximately constant for this same interval of time. This difference in the isotopic records of marine and terrestrial organic matter is considered in terms of the mechanisms controlling the isotopic fractionation associated with photosynthetic fixation of carbon. We show that the decreased isotopic fractionation between marine carbonates and organic matter from the Early to mid-Cenozoic may record variations in the abundance of atmospheric CO2.