WorldWideScience

Sample records for chronological time

  1. 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…

  2. 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…

  3. 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

  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. Self-existing objects and auto-generated information in chronology-violating space-times A philosophical discussion

    CERN Document Server

    Romero, G E; Romero, Gustavo E.; Torres, Diego F.

    2001-01-01

    Closed time-like curves naturally appear in a variety of chronology-violating space-times. In these space-times, the Principle of Self-Consistency demands an harmony between local and global affairs that excludes grandfather-like paradoxes. However, self-existing objects trapped in CTCs are not seemingly avoided by the standard interpretation of this principle, usually constrained to a dynamical framework. In this paper we discuss whether we are committed to accept an ontology with self-existing objects if CTCs actually occur in the universe. In addition, the epistemological status of the Principle of Self-Consistency is analyzed and a discussion on the information flux through CTCs is presented.

  6. 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.

  7. Censorship of Chronological Violations

    CERN Document Server

    Monroe, H

    2006-01-01

    Rich non-arbitrary topological change may occur in a relativistic vacuum space-time that violates chronology at every point. However, each closed timelike curve (CTC) is typically "censored" by passing through a wormhole's event horizon, and a Cauchy-like surface may exist through which all timelike curves pass once and only once before crossing an event horizon. All CTCs in a time-orientable space-time must pass through a wormhole; otherwise the CTC could be deformed as a CTC to a non-time-orientable point. Therefore, if all wormholes have event horizons, there is chronology protection against uncensored CTCs, and the universe is safe for those historians who cannot see through event horizons. An indicator of a space-time's completeness which is conformally invariant, unlike geodesic or b-completeness, is that no causal boundary exists, which implies that the entire space-time is a chronology violating set. Such "causally complete" space-times fail to satisfy assumptions of the topological censorship theorem...

  8. 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

  9. The quantum physics of chronology protection

    OpenAIRE

    Visser, Matt

    2002-01-01

    This is a brief survey of the current status of Stephen Hawking's ``chronology protection conjecture''. That is: ``Why does nature abhor a time machine?'' I'll discuss a few examples of spacetimes containing ``time machines'' (closed causal curves), the sorts of peculiarities that arise, and the reactions of the physics community. While pointing out other possibilities, this article concentrates on the possibility of ``chronology protection''. As Stephen puts it: ``It seems that there is a Ch...

  10. A chronology of financial crises for Norway

    OpenAIRE

    Grytten, Ola Honningdal; Hunnes, Arngrim

    2010-01-01

    The paper offers a chronology of financial crises in Norway from her independence in 1814 till present times. Firstly, business cycles, covering almost two hundred years of economic history are mapped. These reveal years of crises in the real economy. These seem to coincide with most of the major financial crises. Secondly, the paper the financial crises are described chronologically. Thirdly, the paper investigates key patterns in credit and money volumes. It concludes that ma...

  11. Future Chronological Boundary

    CERN Document Server

    Harris, S G

    1997-01-01

    The purpose of this note is to establish, in a categorical manner, the universality of the Geroch-Kronheimer-Penrose causal boundary when considering the types of causal structures that may profitably be put on any sort of boundary for a spacetime. Actually, this can only be done for the future causal boundary (or the past causal boundary) separately; furthermore, only the chronology relation, not the causality relation, is considered, and the GKP topology is eschewed. The final result is that there is a unique map, with the proper causal properties, from the future causal boundary of a spacetime onto any ``reasonable" boundary which supports some sort of chronological structure and which purports to consist of a future completion of the spacetime. Furthermore, the future causal boundary construction is categorically unique in this regard.

  12. Hagedorn transition and chronology protection in string theory

    International Nuclear Information System (INIS)

    String theory is conjectured to be chronologically protected due to condensation of light winding states near closed null curves. Such condensation triggers a Hagedorn phase transition, whose end point is expected to have good chronology. We support this conjecture by studying strings in the Oplane orbifold, where we explicitly see winding states condensing in the pathological region of space-time. The string partition function has infrared divergences associated with the condensation and exhibits Hagedorn behavior, signaling at a phase transition. Contrary to common lore, chronology is protected through an infrared effect. (authors) Keywords: bad chronology, closed causal curves, winding strings, unstable modes, tachyon condensation, Hagedorn transition

  13. 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".

  14. 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...

  15. Nuclear cosmo-chronology

    International Nuclear Information System (INIS)

    Nuclear cosmo-chronology is based on the age determination method by using pairs of isotopes or elements: 235U / 238U, 187Re / 187Os and Th / U or Th / Eu. In this article we examine the age of the galaxy that has been deduced from the analysis of meteorites or from the absorption spectra of the solar light and the age of old stars. Since the solar system is far younger than the galaxy, the evaluation based on the abundances of nuclei in the solar system (absorption spectra of the sun, abundance ratio on meteorites) should take into account a model of the chemistry evolution of the galaxy. The age of the galaxy appears to be somewhere between 12 and 15 Gy with an absolute error of 3 Gy. As for very old stars, they appear to be just a bit older than the galaxy so the evaluation of their age is independent from the chemical evolution of the galaxy. The formation of galaxies began 1 to 2 Gy after the big-bang, the nuclear cosmo-chronology gives the same age for the galaxy as cosmological considerations on the age of the universe do. (A.C.)

  16. 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.

  17. Models for Chronology Selection

    CERN Document Server

    Cassidy, M J

    1998-01-01

    In this paper, we derive an expression for the grand canonical partition function for a fluid of hot, rotating massless scalar field particles in the Einstein universe. We consider the number of states with a given energy as one increases the angular momentum so that the fluid rotates with an increasing angular velocity. We find that at the critical value when the velocity of the particles furthest from the origin reaches the speed of light, the number of states tends to zero. We illustrate how one can also interpret this partition function as the effective action for a boosted scalar field configuration in the product of three dimensional de Sitter space and $S^1$. In this case, we consider the number of states with a fixed linear momentum around the $S^1$ as the particles are given more and more boost momentum. At the critical point when the spacetime is about to develop closed timelike curves, the number of states again tends to zero. Thus it seems that quantum mechanics naturally enforces the chronology p...

  18. Models for chronology selection

    Science.gov (United States)

    Cassidy, M. J.; Hawking, S. W.

    1998-02-01

    In this paper, we derive an expression for the grand canonical partition function for a fluid of hot, rotating massless scalar field particles in the Einstein universe. We consider the number of states with a given energy as one increases the angular momentum so that the fluid rotates with an increasing angular velocity. We find that at the critical value when the velocity of the particles furthest from the origin reaches the speed of light, the number of states tends to zero. We illustrate how one can also interpret this partition function as the effective action for a boosted scalar field configuration in the product of three dimensional de Sitter space and S1. In this case, we consider the number of states with a fixed linear momentum around the S1 as the particles are given more and more boost momentum. At the critical point when the spacetime is about to develop closed timelike curves, the number of states again tends to zero. Thus it seems that quantum mechanics naturally enforces the chronology protection conjecture by superselecting the causality violating field configurations from the quantum mechanical phase space.

  19. Nuclear cosmo-chronology

    International Nuclear Information System (INIS)

    The nuclear cosmo-chronology is based on radioactive dating which makes use of isotope or element pairs. In this paper we investigate the galaxy age estimations which can be deduced from meteorite analysis and solar or certain old stars light absorption spectra. These evaluations are based on theoretical models different then those implied in cosmology. They imply the calculation of heavy nuclei production in r process. The most significant difficulty of this calculation arises from the necessity of simultaneous evaluation of the production of a large number of nuclei what implies the difficult application of the microscopic nuclear models. Since the solar system is young as compared to the age of galaxy the evaluation based on element abundances (deduced from sun absorption spectra or meteorite analyses) requires a chemical evolution model of the galaxy. So far such an evaluation based on all the pairs of nuclear chronometers was not possible with a single set of parameters. Recent progress in estimating the absorption neutron cross section and decay schemes in the star inner environment will allow solving this difficulty

  20. 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.

  1. 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".

  2. 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...

  3. Timing of False Ring Formation in Pinus halepensis and Arbutus unedo in Southern Italy: Outlook from an Analysis of Xylogenesis and Tree-Ring Chronologies

    Science.gov (United States)

    De Micco, Veronica; Balzano, Angela; Čufar, Katarina; Aronne, Giovanna; Gričar, Jožica; Merela, Maks; Battipaglia, Giovanna

    2016-01-01

    Mediterranean tree rings are characterized by intra-annual density fluctuations (IADFs) due to partly climate-driven cambial activity. IADFs are used as structural signals to gain information on relations between environmental conditions and eco-physiological processes during xylogenesis, with intra-annual resolution. To reach an unbiased synchronization of the IADF position within tree rings and seasonal fluctuations in environmental conditions, it is necessary to know the timing of cambial activity and wood formation, which are species- and site-specific processes. We applied the microcoring technique to analyze xylogenesis in Pinus halepensis and Arbutus unedo. To the best of our knowledge, this is the first attempt to study xylogenesis in a hardwood species forming frequent IADFs. Both species co-occur at a site in southern Italy characterized by a Mediterranean climate. To facilitate tree-ring dating and identification of IADFs, we performed traditional dendroecological analysis. We analyzed xylogenesis during summer, which is considered a constraint for xylogenesis and a trigger for IADF formation. We followed the different phases of cell development in the current wood increment with the aim of evaluating whether and which type of IADFs were formed. We additionally analyzed the same phases again in September and in winter to verify the possible formation of IADFs in fall and whether cell production and differentiation was completed by the end of the calendar year. Both species formed the same type of IADFs (earlywood-like cells within latewood), due to temporary growth restoration triggered by rain events during the period of summer drought. At the end of the calendar year, no cells in the phases of enlargement and secondary cell wall deposition occurred. A. unedo was more sensitive than P. halepensis because IADFs were formed earlier in the season and were more frequent in the tree-ring series. The dendro-anatomical approach, combining analysis of tree

  4. CHRONOLOGICAL INVENTORY OF CHEMISTRY TEACHING

    Directory of Open Access Journals (Sweden)

    LAXMAN S. BHATTAR

    2013-05-01

    Full Text Available 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 BCgiven 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 kineticand atomic theory. Nestorians-Arabian (800 to 900BC explains the translated literatureon Alchmey in to Arabic language. Jabiri Bn Hayyan (900to 969 to 1000 yearspublished book on Alchemy.

  5. Chronology of early lunar crust

    Science.gov (United States)

    Dasch, E. J.; Nyquist, L. E.; Ryder, G.

    1988-01-01

    The chronology of lunar rocks is summarized. The oldest pristine (i.e., lacking meteoritic contamination of admixed components) lunar rock, recently dated with Sm-Nd by Lugmair, is a ferroan anorthosite, with an age of 4.44 + 0.02 Ga. Ages of Mg-suite rocks (4.1 to 4.5 Ga) have large uncertainties, so that age differences between lunar plutonic rock suites cannot yet be resolved. Most mare basalts crystallized between 3.1 and 3.9 Ga. The vast bulk of the lunar crust, therefore, formed before the oldest preserved terrestrial rocks. If the Moon accreted at 4.56 Ga, then 120 Ma may have elapsed before lunar crust was formed.

  6. 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

  7. 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)

  8. 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...

  9. 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...

  10. 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.

  11. 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.

  12. Chronological changes in hypertensive intracerebral hemorrhages

    International Nuclear Information System (INIS)

    The clinical series consisted of 28 patients with hypertensive intracerebral hematoma observed in the natural course from 1976 through 1978. A total of 114 repeated computer tomographic (CT) examinations were made with an EMI-1010 or an ACTA-0100 scanner. The experimental series consisted of 26 adult mongrel dogs with intracerebral hematoma near the basal ganglia. In 20 dogs, autopsy and histological examinations were performed, and in 12 dogs a total of 31 repeated CT examinations were carried out with an EMI scanner (matrix 320 x 320, high-definition scan). In the clinical series, the time of the decrease in density beginning in the periphery of the hematoma, like the first appearance of ring enhancement and its concentric concentration toward the center of the hematoma, was not affected by the size of the hematoma. However, the time when the intracerebral hematoma was resolved did vary with the size of the hematoma. In the experimental series, the tissue reaction near the periphery of the intracerebral hematoma seemed to be a constant process. First, a necrotic layer appeared, and then this was replaced by immature connective tissue with granular cells, newly formed vessels, and reticulin fibers; finally, the immature layer was gradually transformed into mature connective tissue with collagenous fibers. Moreover, this process of change was not related to the size of the hematoma. The following correlations were suggested by a chronological observation of the CT images and the histological appearance: 1) acute stage - homogeneous high-density extending to the periphery, apperance of a necrotic layer; 2) subacute stage - decreased density spreading from the periphery and formation of ring enhancement, apperance of immature connective tissue with reticulin fibers; 3) chronic stage - concentric concentration of ring enhancement, mature connective tissue with collagenous fibers

  13. [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

  14. 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

  15. 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

  16. The New Chronology of Iron Age Gordion

    OpenAIRE

    Aslan, Carolyn C.

    2013-01-01

    The Classical Review http://journals.cambridge.org/CAR Additional services for The Classical Review: Email alerts: Click here Subscriptions: Click here Commercial reprints: Click here Terms of use : Click here C.B. Rose, G. Darbyshire (edd.) The New Chronology of Iron Age Gordion. (Gordion Special Studies 6.) Pp. xiv + 181, gs, ills, maps. Philadelphia: University of Pennsylvania Museum of Archaeology and Anthropology, 2011. Cased, £45.50, US\\$69.95. ISBN:...

  17. 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.

  18. 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

  19. 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

  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. Early Mars: A regional assessment of denudation chronology

    Science.gov (United States)

    Maxwell, T. A.; Craddock, R. A.

    1993-01-01

    Within the oldest highland units on Mars, the record of crater degradation indicates that fluvial resurfacing was responsible for modifying the Noachian through middle-Hesperian crater population. Based on crater frequency in the Noachian cratered terrain, age/elevation relations suggest that the highest exposures of Noachian dissected and plateau units became stabilized first, followed by successively lower units. In addition, studies of drainage networks indicate that the frequency of Noachian channels is greatest at high elevations. Together, these observations provide strong evidence of atmospheric involvement in volatile recycling. The long time period of crater modification also suggests that dendritic highland drainage was not simply the result of sapping by release of juvenile water, because the varied geologic units as well as the elevation dependence of stability ages makes it unlikely that subsurface recycling could provide a continuous supply of water for channel formation by sapping. While such geomorphic constraints on volatile history have been established by crater counts and stratigraphic relations using the 1:2M photomosaic series, photogeologic age relationships at the detailed level are needed to establish a specific chronology of erosion and sedimentation. Age relations for discrete erosional slopes and depositional basins will help refine ages of fluvial degradation, assess effectiveness of aeolian processes, and provide a regional chronology of fluvial events.

  2. 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.

  3. Testing OSL failures against a regional glaciation chronology from southern Scandinavia

    DEFF Research Database (Denmark)

    Houmark-Nielsen, Michael

    2008-01-01

    Scandinavia agree with the glaciation chronology predicted by numerical and relative ages, but not all. Overestimation of the expected timing seems to arise from an inherited signal acquired prior to the latest depositional episode. Here, the geological context is examined for solifluction deposits that cap...

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

    Science.gov (United States)

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

    2015-04-01

    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 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.

  6. Geochemical alterations and chronology in archaeology

    International Nuclear Information System (INIS)

    Studies about hydrogen and fluorine incorporation in various materials used by the prehistoric man, bring to archaeological stratigraphies important information about chronology. Ion beams methods of analysis (such as AGLAE for the Louvre museum), provide depth resolution together with high detection sensitivity. They allow to pursue researches most often without sampling the artefacts. Some resonance nuclear reactions, such as produced by nitrogen 15 nucleus and protons, allow for measuring the concentration profile of fluorine and hydrogen present in the outer micrometer of the surface. Examples of the obsidian hydration and the fluorine penetration in flint or paleontological remains, show the interest of these methods to complement traditional methods of absolute dating. (author). 3 figs., 2 tabs., 34 refs

  7. 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…

  8. U. S. Military Documentary Films: A Chronological Analysis.

    Science.gov (United States)

    Avery, Robert K.; Larson, Timothy L.

    After presenting a chronological account of United States military documentary films from World War I through the Vietnam War, this paper reports on a study that compared the effectiveness of films prepared during World War II, the Korean War, and the Vietnam War. The first section, the chronological account, touches on such subjects as the…

  9. 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.

  10. 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

  11. Astronautics and aeronautics, 1970. Chronology on science, technology, and policy

    Science.gov (United States)

    1972-01-01

    An immediate reference to aerospace-related events of 1970 is provided to help historians in preserving historical accuracy and precision. Chronologies of major NASA launches, and manned space flights for 1970 are included.

  12. 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.

  13. 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

  14. Correlation between Chronological Age, Dental Age and Skeletal Age among Monozygoyic and Dizygotic Twins

    OpenAIRE

    Gupta, Mohit; Divyashree, R; Abhilash, PR; A Bijle, Mohammed Nadeem; Murali, KV

    2013-01-01

    Introduction: Chronological age, dental development, height and weight measurements, sexual maturation characteristics and skeletal age are some biological indicators that have been used to identify time of growth. Many researchers have agreed that skeletal maturity is closely related to the craniofacial growth, and bones of hand and wrist are reliable parameters in assessing it. The complete hand and wrist radiograph involves 30 bones and assessment of these bones is one elaborate task. The ...

  15. 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

  16. 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

  17. Chronology protection in Galileon models and massive gravity

    Energy Technology Data Exchange (ETDEWEB)

    Burrage, Clare; Rham, Claudia de; Heisenberg, Lavinia [Départment de Physique Théorique and Center for Astroparticle Physics, Université de Genève, 24 Quai E. Ansermet, CH-1211 Genève (Switzerland); Tolley, Andrew J., E-mail: Clare.Burrage@nottingham.ac.uk, E-mail: claudia.deRham@case.edu, E-mail: Lavinia.heisenberg@googlemail.com, E-mail: andrew.j.tolley@case.edu [Department of Physics, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106 (United States)

    2012-07-01

    Galileon models are a class of effective field theories that have recently received much attention. They arise in the decoupling limit of theories of massive gravity, and in some cases they have been treated in their own right as scalar field theories with a specific nonlinearly realized global symmetry (Galilean transformation). It is well known that in the presence of a source, these Galileon theories admit superluminal propagating solutions, implying that as quantum field theories they must admit a different notion of causality than standard local Lorentz invariant theories. We show that in these theories it is easy to construct closed timelike curves (CTCs) within the naive regime of validity of the effective field theory. However, on closer inspection we see that the CTCs could never arise since the Galileon inevitably becomes infinitely strongly coupled at the onset of the formation of a CTC. This implies an infinite amount of backreaction, first on the background for the Galileon field, signaling the break down of the effective field theory, and subsequently on the spacetime geometry, forbidding the formation of the CTC. Furthermore the background solution required to create CTCs becomes unstable with an arbitrarily fast decay time. Thus Galileon theories satisfy a direct analogue of Hawking's chronology protection conjecture.

  18. The Christian chronologies of the creation and the view of modern astrophysics

    Science.gov (United States)

    Theodossiou, E. Th.

    2004-01-01

    How many different chronologies have been proposed for the beginning of the Creation? It is, of course, well known that the Jewish chronology starts from 7 October (1 Tishri) 3761 BC; however, this starting point apparently did not satisfy various scholars nor Christian savants and astronomers. As a result, from time to time miscellaneous dates were being proposed, from the Jewish historian Josephus (first Century AD) up to the French humanist Joseph Scaliger (1484-1558) and the famous Polish astronomer Johannes Hevelius (1611-87). Not only the scholars of these eras but also the Christian Churches defined through Ecumenical Council decisions the beginning of the Creation. In this study we present the proposed dates, while we note that especially the date proposed by James Ussher (1581-1656), Archbishop of Armagh (Northern Ireland), that is the year 4004 BC and not the centurial year 4000 BC, is due to the historians' belief that Herod died in 4 BC. Thus, Ussher added these 4 years to the year 4000 BC in order to have a more accurate chronology in respect to the birth of Christ, a birth placed by him, as well as by many chronicle writers of the era, in 4 BC.

  19. 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.

  20. 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 .

  1. 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

  2. Aspects of the Weichselian chronology In central East Greenland

    DEFF Research Database (Denmark)

    Funder, Svend Visby; Hjort, Christian

    1973-01-01

    From central East Greenland, CH ages between 19,500 - >40,000 years B.P. have been obtained for six samples of marine bivalve shells. The ages seem to be consistent with geological observations and form the basis for a tentative chronology for the vVeichselian ice age in the region. It appears that...

  3. 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

  4. 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

  5. A multi-archive coherent chronology: from Greenland to the Mediterranean sea

    Science.gov (United States)

    Bazin, Lucie; Landais, Amaelle; Lemieux-Dudon, Bénédicte; Siani, Giuseppe; Michel, Elisabeth; Combourieu-Nebout, Nathalie; Blamart, Dominique; Genty, Dominique

    2015-04-01

    . & Wolff, E., An optimized multi-proxy, multi-site Antarctic ice and gas orbital chronology (AICC2012): 120-800 ka,Clim. Past 9, 1715-1731, 2013. Genty, D., Blamart, D., Ghaleb B., Plagnes, V., Causse, Ch., Bakalowicz, M., Zouari, K., Chkir, N., Hellstrom, J., Wainer, K., Bourges, F., Timing and dynamics of the last deglaciation from European and North African δ13C stalagmite profiles - comparison with Chinese ans South Hemisphere stalagmites, Quat. Sci. Rev. 25, 2118-2142, 2006. Lemieux-Dudon, B. ; Blayo, E. ; Petit, J.-R. ; Waelbroeck, C. ;Svensson, A. ; Ritz, C. ; Barnola, J.-M. ; Narcisi, B.M. ; Parrenin, F., Consitent dating for Antarctic and Greenland ice cores, Quat. Sci. Rev. 29(1-2), 2010. Veres, D. ; Bazin, L. ; Landais, A. ; Lemieux-Dudon, B. ; Parrenin, F. ; Martinerie, P. ; Toyé Mahamadou Kele, H. ; Capron, E. ; Chappellaz, J. ; Rasmussen, S. ; Severi, M. ; Svensson, A. ; Vinther, B. & Wolff, E., The Antarctic ice core chronology (AICC2012): an optimized multi-parameter and multi-site dating approach for the last 120 thousand years, Clim. Past, 9, 1733-1748, 2013.

  6. The Bampur Valley: A New Chronological Development

    OpenAIRE

    Mortazavi, Mehdi

    2006-01-01

    The study of history gives one access less directly but often no less vividly – to hundreds of years of recorded time. But it is only archaeology, in particular prehistoric archaeology, that opens up the almost unimaginable vistas of thousands and even a few millions of years of past human existence (Renfrew & Bahn, 2001: 117). The stratigraphical sequence at Tepe Bampur, which has been divided into six periods, was firstly studied by De Cardi in 1966 (Lamberg-Karlovsky & Schma...

  7. 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.

  8. Chronology and alteration of cyclic drainage events for ice-dammed Lake Tiningnilik, Greenland, in 2010

    DEFF Research Database (Denmark)

    Haase, Eric Juergen; Furuya, Masato; Korsgaard, Niels Jákup;

    climate change in Greenland. We take a close look at Lake Tiningnilik and previous studies to constrain the timing of the drainage events using historical air photos and satellite imagery starting in the 1940s and 1970s, respectively. Tiningnilik has been occasionally surveyed on the ground since the 1980......s and since the late 1990s regularly scanned by both aircraft and satellite laser altimetry, as well as satellite radar. Incorporating these data we are able to close some gaps in the historic chronology of the drainage events and suggest mechanisms to account for the recent change in the stable...

  9. Absolute Chronology of Deep-Sea Sediments and the Deposition of Clay on the Ocean Floor

    OpenAIRE

    Kullenberg, B.

    2011-01-01

    An absolute chronology of deep-sea sediments on the basis of the accumulation of TiO2 presupposes the rate of accumulation of clay to be tolerably constant with regard to time. It is here asserted that this condition is not fulfilled, because 1) the supply of fine terrigeneous matter to offshore waters will be appreciably affected by climatic changes, 2) the total amount of fine terrigeneous matter carried in suspension by sea water is deposited in about 300 years, which is a small fraction o...

  10. Chronology protection in stationary 3D spacetimes

    Czech Academy of Sciences Publication Activity Database

    Raeymaekers, Joris

    2011-01-01

    Roč. 2011, č. 11 (2011), 1-19. ISSN 1126-6708 R&D Projects: GA ČR GAP203/11/1388 Grant ostatní: EUROHORC and ESF(XE) EYI/07/E010 Institutional research plan: CEZ:AV0Z10100502 Keywords : conformal field theory * causality violation * null-energy condition violation * energy-momentum tensor * AdS/CFT * time machine * Einstein equation Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 5.831, year: 2011 http://link.springer.com/article/10.1007%2FJHEP11%282011%29024

  11. 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.

  12. Geological time formalization: an improved formal model for describing time successions and their correlation

    OpenAIRE

    Perrin, Michel; Mastella, Laura S.; Morel, Olivier; Lorenzatti, Alexandre

    2011-01-01

    Geological time description largely rests on an event based chronology based on the stratigraphical model. It uses a hierarchy of chronologically ordered geochronological units and boundaries. In order to be easily dealt with within large databases used by complex engineering systems, the geological time chronology must be formalized. Stratigraphical time successions should accordingly be described by using adequate semantic tools (ontologies) complemented by a set of logical rules. At presen...

  13. Gödel-type universes and chronology protection in Hořava–Lifshitz gravity

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca-Neto, J.B.; Petrov, A.Yu. [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, 58051-970, João Pessoa, PB (Brazil); Rebouças, M.J., E-mail: reboucas.marcelo@gmail.com [Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, RJ (Brazil)

    2013-10-01

    In the attempts toward a quantum gravity theory, general relativity faces a serious difficulty since it is non-renormalizable theory. Hořava–Lifshitz gravity offers a framework to circumvent this difficulty, by sacrificing the local Lorentz invariance at ultra-high energy scales in exchange of power-counting renormalizability. The Lorentz symmetry is expected to be recovered at low and medium energy scales. If gravitation is to be described by a Hořava–Lifshitz gravity theory there are a number of issues that ought to be reexamined in its context, including the question as to whether this gravity incorporates a chronology protection, or particularly if it allows Gödel-type solutions with violation of causality. We show that Hořava–Lifshitz gravity only allows hyperbolic Gödel-type space-times whose essential parameters m and ω are in the chronology respecting intervals, excluding therefore any noncausal Gödel-type space-times in the hyperbolic class. There emerges from our results that the famous noncausal Gödel model is not allowed in Hořava–Lifshitz gravity. The question as to whether this quantum gravity theory permits hyperbolic Gödel-type solutions in the chronology preserving interval of the essential parameters is also examined. We show that Hořava–Lifshitz gravity not only excludes the noncausal Gödel universe, but also rules out any hyperbolic Gödel-type solutions for physically well-motivated perfect-fluid matter content.

  14. Spatial and Temporal Complexities of Current Great Plains Dunefield Chronological Data

    Science.gov (United States)

    Halfen, A. F.; Johnson, W. C.

    2012-12-01

    The North American Great Plains span nearly 2.8 million km2, of which nearly half is mantled by aeolian sediments (loess deposits, sand sheets, and dunefields). Stratigraphies of these sediments contain a rich history of late-Quaternary climate change, in particular aeolian dunefields, which provide a record of drought. During arid conditions in the Great Plains, stabilizing vegetation is diminished, leaving dunefields susceptible to aeolian erosion; during periods of increased moisture, conversely, vegetation re-establishes and dunefields stabilize. Using radiometric dating techniques, researchers can extract from the stratigraphy of dunefields the timing of past activity, and, therefore, periods of past drought. To date, more than 50 chronologies, comprised of over 700 ages, have established a detailed record of past dunefield activity in the Great Plains. Despite this extensive dataset, correlating periods of past droughts across the region remains problematic, in large part due to the spatial and temporal limitations in the data. In this poster, we present a spatial and temporal synthesis of current Great Plains dunefield chronologies, followed by an analysis of the complexities of these data, in particular when used to determine periods of past drought. To illustrate these complexities, we present a bicentennial, 1 x 1 degree gridded model of dune activity (e.g., active, stable, no data) spanning the last 2000 years. Our model clearly illustrates gaps in spatial coverage and temporal biases of chronologies. To further highlight the complexities of using current Great Plains datasets as proxies for prehistoric drought, we compare a 2.5 x 2.5 degree gridded model of dune activity during the Medieval Climatic Anomaly (A.D. 1000-1400) and historic time (A.D. 1800-2000) to Palmer Drought Severity Index (PDSI)-reconstructed droughts for the same time intervals. In general, dunefield activity is in good agreement with PDSI-reconstructed drought, however, unlike tree

  15. 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:

  16. 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.

  17. 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 ...

  18. 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...

  19. 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

  20. 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.

  1. Chronology of metal pollution offshore Coruh Mouth, Eastern Black Sea

    International Nuclear Information System (INIS)

    mouth clearly confirms the river as the source of input of heavy metals. The vertical distributions of copper concentrations are characterized by ample fluctuations (the profile at one of the sampled sites is illustrated). 137Cs was used to derive down-core chronology and, until further insight will be obtained on post-depositional processes, the observed variations in the Cu profile were tentatively attributed to variations in the input resulting from copper industry upstream Coruh. The most likely source lies in the Artvin area, where a major Cu processing center, Murgul-Artvin, is located, about 60 km from the mouth of the river. The most likely source for the increased Ba concentrations is the Cerattepe high-grade gold ore deposit near Artvin, where gold is located in oxidized barite rich units and the mining and processing of the ore results in a great quantity of Ba rich wastes. No detailed production data are at this stage available for these industries, however global data were available for Cu mining in Turkey since the early 1960s. The timeline corresponding to the measured Cu profile in Fig. 1, when taking into account transport, deposition and post-depositional processes, matches fairly well key time points such as: significant growth of the mining industry in the mid 1930s; actions to address environmental concerns starting to be implemented in the 1970s and being consolidated with the Turkish Environmental Law coming into force in 1973. Further detailed studies and additional information will be required to make a complete assessment of the site's contamination, to trace the burying of the sub-surface Cu peak, to corroborate chronologies using additional tracers and to identify effects of post-depositional processes. Combined with previous results obtained by the authors on the buffering capacity of this river's watershed, this study could improve the predictive capabilities concerning the fate of contaminants released in or deposited on the basin

  2. Chronology of metal pollution offshore Coruh mouth, eastern Black Sea

    International Nuclear Information System (INIS)

    mouth clearly confirms the river as the source of input of heavy metals. The vertical distributions of copper concentrations are characterized by ample fluctuations. 137Cs was used to derive down-core chronology and, until further insight will be obtained on post-depositional processes, the observed variations in the Cu profile were tentatively attributed to variations in the input resulting from copper industry upstream Coruh. The most likely source lies in the Artvin area, where a major Cu processing center, Murgul- Artvin, is located, about 60 km from the mouth of the river. The most likely source for the increased Ba concentrations is the Cerattepe high-grade gold ore deposit near Artvin, where gold is located in oxidized barite rich units and the mining and processing of the ore results in a great quantity of Ba rich wastes. No detailed production data are at this stage available for these industries, however global data were available for Cu mining in Turkey since the early 1960s. The timeline corresponding to the measured Cu profile, when taking into account transport, deposition and post-depositional processes, matches fairly well key time points such as: significant growth of mining industry in the mid 1930s; actions to address environmental concerns starting to be implemented in the 1970s and being consolidated with the Turkish Environmental Law coming into force in 1973. Further detailed studies and additional information will be required to make a complete assessment of the site's contamination, to trace the burying of the sub-surface Cu peak, to corroborate chronologies using additional tracers and to identify effects of post-depositional processes. Combined with previous results obtained by the authors on the buffering capacity of this river's watershed, this study could improve the predictive capabilities concerning the fate of contaminants released in or deposited on the basin

  3. A Toolbox for Rapid Quantitative Assessment of Chronological Lifespan and Survival in Saccharomyces cerevisiae.

    Science.gov (United States)

    Chadwick, Sarah R; Pananos, Athanasios D; Di Gregorio, Sonja E; Park, Anna E; Etedali-Zadeh, Parnian; Duennwald, Martin L; Lajoie, Patrick

    2016-06-01

    Saccharomyces cerevisiae is a well-established model organism to study the mechanisms of longevity. One of the two aging paradigms studied in yeast is termed chronological lifespan (CLS). CLS is defined by the amount of time non-dividing yeast cells can survive at stationary phase. Here, we propose new approaches that allow rapid and efficient quantification of survival rates in aging yeast cultures using either a fluorescent cell counter or microplate imaging. We have generated a software called analysr (Analytical Algorithm for Yeast Survival Rates) that allows automated and highly reproducible analysis of cell survival in aging yeast cultures using fluorescent data. To demonstrate the efficiency of our new experimental tools, we tested the previously characterized ability of caloric restriction to extend lifespan. Interestingly, we found that this process is independent of the expression of three central yeast heat shock proteins (Hsp26, Hsp42, Hsp104). Finally, our new assay is easily adaptable to other types of toxicity studies. Here, we assessed the toxicity of various concentrations of acetic acid, a known contributor of yeast chronological aging. These assays provide researchers with cost-effective, low- and high-content assays that can serve as an efficient complement to the time-consuming colony forming unit assay usually used in CLS studies. PMID:26939796

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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...

  9. Approaches to chronological age assessment based on dental calcification.

    Science.gov (United States)

    Bolanos, M V; Manrique, M C; Bolanos, M J; Briones, M T

    2000-05-15

    The aim of the present study was to find an accurate estimation of chronological age using a small number of selected teeth. For this purpose, the method devised by Nolla [C. Nolla, The development of the permanent teeth, J. Dent. Child. 27 (1960) 254-266.] was used: the development of each of the teeth was determined according to this method on 374 radiographs, 195 of boys (mean age 8.59) and 179 of girls (mean age 8.75). The 28 variables representing the calcification stages were analyzed using cluster analysis followed by multivariate analysis (multiple linear regression model). Patient age was considered to be a dependent variable. Our study showed that antimere teeth are the most homogeneous as regards stages of development. The prediction was more accurate for boys and girls below 10 years of age, using teeth 21, 43 and 46 from boys and teeth 21, 46 and 47 from girls. These teeth accounted for 80% total variance of chronological age for dental calcification. Standard error was +/-1.4 years for boys and +/-1.2 years for girls. When the age of the children remained completely unknown, the best estimates were provided by teeth 43, 47, 46 and 44 from boys and teeth 44, 47 and 43 from girls. PMID:10808098

  10. 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.

  11. A review of the chronologies and geomorphology of the aeolian landforms in the northwestern Negev dunefield (Israel)

    Science.gov (United States)

    Roskin, Joel

    2015-04-01

    The northwestern (NW) Negev Desert dunefield covering an area of only 1,300 km2, comprises the eastern end of the northern Sinai Peninsula - NW Negev erg and is probably the most densely dated dune body in the INQUA Dunes Atlas chronologic database. Over 230 luminescence ages (TL, IRSL, and mainly OSL) and radiocarbon dates have been retrieved over the past course of 20 years from calcic and sandy palaeosols serving as dune substrates, sand sheets, vegetated linear dunes (VLDs), fluvial deposits, and archaeological sites. Despite being from different deposit types and aeolian morphologies, and based on different methodologies, the chronologies usually show good compatibility. By reviewing and reassessing the significance of the Eastern Mediterranean INQUA Dunes Atlas chronologies, along with detailed stratigraphic, structural and geomorphologic data and understandings, the major, and possibly extreme, episodes of aeolian activity and stability are outlined. Repetitive chronostratigraphic sequences in VLDs indicate that this dune type, at least in the Negev, comprises a reliable recorder of main dune mobilization periods. This presentation demonstrates that certain combinations of research finds, using different OSL dating strategies and other regional and local late Quaternary records and in particular aeolian ones, are required assets for providing for acceptable local and regional palaeoclimatic interpretations. The distribution of the VLD chronologies points to rapid mobilization during the Heinrich 1 and Younger Dryas, characterized by powerful winds, though VLDs also form in late Holocene palaeoenvironments. Time slices illustrate the different sensitivities of the studied aeolian landforms to the source, availability, and supply of sediment; long- and short-term climate change, local human-induced environmental changes and also their joint effects, that enable evaluation of aeolian responses to future environmental and climate changes.

  12. Luminescence chronologies for sediments recording paleoseismic events and slip rate for the central Garlock fault, California, USA

    Science.gov (United States)

    Okubo, S. G.; Wolf, E.; Roder, B. J.; Rhodes, E. J.; McGill, S. F.; Dolan, J. F.; Mcauliffe, L. J.; Lawson, M. J.; Barrera, W. A.

    2012-12-01

    Luminescence dating has a significant role to play in providing chronological control for lacustrine and alluvial sediments that record both tectonic and climatic events. However, poor characteristics in some environments mean that the well-established method of OSL (optically stimulated luminescence) dating of quartz is not well-suited for the material available. In order to overcome this significant limitation, a range of methods based on the IRSL (infra-red stimulated luminescence) and ITL (isothermal thermoluminescence) of K-feldspar are currently under development. The site of El Paso Peaks, California has an established C-14 chronology spanning the last 7,000 years for a series of playa sediments comprising silts and fine sands, with occasional incursions of coarser sands and gravels from the alluvial fan that forms one side of the small ephemeral lake basin. Another barrier is formed by a shutter ridge of the left-lateral central Garlock fault, and this succession of sediments records at least six seismic events. Following collection of a suite of 24 luminescence samples distributed throughout the upper part of this succession, this site provides a rare opportunity to test different luminescence dating protocols in a rigorous fashion. At the site of Christmas Canyon West, a few miles further east, numerous small offsets of depositional and erosional alluvial fan features provide the opportunity to determine slip rates for a variety of timescales spanning the past couple of thousand years, besides forming a record of the timing of several discrete depositional episodes representing local high precipitation events. We review the challenges involved in developing a reliable luminescence chronology for sediment deposition in these contexts, and in relating this chronology to significant environmental events.

  13. 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.

  14. 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

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

    Science.gov (United States)

    Connelly, James N; Bizzarro, Martin; Krot, Alexander N; Nordlund, Åke; Wielandt, Daniel; Ivanova, Marina A

    2012-11-01

    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 and chondrules from primitive meteorites. CAIs define a brief formation interval corresponding to an age of 4567.30 ± 0.16 million years (My), whereas chondrule ages range from 4567.32 ± 0.42 to 4564.71 ± 0.30 My. These data refute the long-held view of an age gap between CAIs and chondrules and, instead, indicate that chondrule formation started contemporaneously with CAIs and lasted ~3 My. This time scale is similar to disk lifetimes inferred from astronomical observations, suggesting that the formation of CAIs and chondrules reflects a process intrinsically linked to the secular evolution of accretionary disks. PMID:23118187

  16. 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: <30 years...... 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...

  17. Hawking's chronology protection conjecture singularity structure of the quantum stress--energy tensor

    CERN Document Server

    Visser, M

    1994-01-01

    The recent renaissance of wormhole physics has led to a very disturbing observation: If traversable wormholes exist then it appears to be rather easy to to transform such wormholes into time machines. This extremely disturbing state of affairs has lead Hawking to promulgate his chronology protection conjecture. This paper continues a program begun in an earlier paper [Physical Review {\\bf D47}, 554--565 (1993), hepth@xxx/9202090]. An explicit calculation of the vacuum expectation value of the renormalized stress--energy tensor in wormhole spacetimes is presented. Point--splitting techniques are utilized. Particular attention is paid to computation of the Green function [in its Hadamard form], and the structural form of the stress-energy tensor near short closed spacelike geodesics. Detailed comparisons with previous calculations are presented, leading to a pleasingly unified overview of the situation.

  18. Chronology of Fabry-Perot Interferometer Fiber-Optic Sensors and Their Applications: A Review

    Directory of Open Access Journals (Sweden)

    Md. Rajibul Islam

    2014-04-01

    Full Text Available 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.

  19. 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.

  20. Construction validity in equilibrium tests: chronological order in tasks presentation

    Directory of Open Access Journals (Sweden)

    Maria Duarte Caetano

    2006-09-01

    Full Text Available The equilibrium tests of the Rosa Neto1 Motor evelopment Scale are constituted by ten tasks related to the chronological ages from 2 to 11 years and they determine the participants Motor Age. The tests presentation order is crescent from the child chronological age and the motor age is based on the success or failure in each task. The aim of this study was to analyze the construction validity of the equilibrium motor tests observing the ordering the levels of task difficulty. 76 children with 6 to 9 years of chronological age participated and were assigned in two groups: control group, tests presentation in increased order; and inverted group, tests presentation in decreased order. The results did not revealed statistical significant differences between groups, which indicatethat the presentation order of the tests did not interfere in the children performance, independently of the chronological age. Low success rates occurred in some specific tasks followed by success in advanced tasks. As the results revealed that the participants could perform the tasks after that in which the failure happened the motor age ascribed by the Motor Development Scale can underestimate the children motor development. The variation of the children performance in the tasks suggests that the motor development process is nonlinear. The equilibrium motor tasks purposed in the Motor Development Scale show construction validity. RESUMO Os testes de equilíbrio da Escala de Desenvolvimento Motor de Rosa Neto1 são constituídos por dez tarefas correspondentes às idades cronológicas de 2 a 11 anos e determinam a Idade Motora dos participantes. A ordem de apresentação dos testes é crescente, partindo da idade cronológica da criança e a idade motora baseia-se no sucesso ou fracasso em cada tarefa. O objetivo deste estudo foi analisar a validade de construção dos testes motores em equilíbrio, observando a ordenação e os graus de dificuldade da tarefa. Participaram

  1. Thermoluminescence dating. Application to the chronology of volcanic ashes

    International Nuclear Information System (INIS)

    Thermoluminescent (TL) dating is generally used for minerals heated in the past and can be used for absolute chronology of volcanic ashes but seems limited to less than 15.000 years. The aim of the thesis is the study of thermoluminescent properties of quartz for high doses and long irradiations using the red TL peak of quartz which is situated at high temperature (about 370 deg. C) to extend the method for higher ages. A theory, based on spatial correlation between electron and hole created during the same ionization, is developed. A chapter is devoted to dosimetry because of its importance in TL dating, especially alpha scintillation counting and the influence of humidity on the determination of annual dose. Volcanic samples are dated from 10.000 to 80.000 years before present

  2. 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.

  3. 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

  4. School Attendance Patterns, Unmet Educational Needs, and Truancy: A Chronological Perspective

    Science.gov (United States)

    Spencer, Andrea M.

    2009-01-01

    This study examines chronological patterns of attendance and academic performance of urban students who are identified as truants in Grade 8. A chronological review of 42 student records, from school entry through Grade 8, identified high frequencies of absenteeism and academic performance issues beginning at school entry and, in many cases,…

  5. 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

  6. Asynchronous Glacial Chronologies in the Central Andes (15-40°S) and Paleoclimatic Implications

    Science.gov (United States)

    Zech, R.; Kull, C.; Kubik, P. W.; Veit, H.

    2006-12-01

    We have established glacial chronologies along a N-S transect over the Central Andes using 10Be surface exposure dating. Our results show that maximum glacial advances occurred asynchronously and reflect the varying influence and shifts of the major atmospheric circulation systems during the Late Quaternary: the tropical circulation in the north and the westerlies in the south. In Bolivia (three research areas in the Cordillera Real and the Cordillera Cochabamba, ~15°S) glacial advances could be dated to ~20 and 12 ka BP. This is in good agreement with published exposure age data from moraines in Bolivia and Peru (provided that all ages are calculated following the same scaling system). Accordingly, the maximum glaciation there probably occurred roughly synchronous to the temperature minimum of the global Last Glacial Maximum (LGM) and the lateglacial cold reversals. Strict correlation with neither the Younger Dryas in the northern hemisphere, nor the Antarctic Cold Reversal is possible due to the current systematic exposure age uncertainties (~10%). Glacier-Climate-Modelling corroborates the sensitivity of the reconstructed glaciers to temperature changes, rather than precipitation. On the contrary, there is good evidence for the dominant role of precipitation changes on the glacial chronologies in the lee of the Cordillera Occidental, i.e. on the Altiplano and further south. The pronounced lateglacial wet phase, which is well documented in lake transgression phases as far south as 28°S (-> tropical moisture source), seems to have caused glacial advances even at ~30°S. In two research areas in Chile at that latitude, we were able to date several lateglacial moraines. Besides, the maximum datable glaciation there occurred at ~30 ka BP. That is significantly earlier than the LGM (sensu strictu) and points to favourable climate conditions for glaciation at that time (particularly increased precipitation). We conclude that the westerlies were more intensive or

  7. A sub-fossil kauri (Agathis australis) tree-ring chronology

    International Nuclear Information System (INIS)

    A 491-year floating tree-ring chronology was constructed using sub-fossil bog kauris, Agathis australis, from a site near Huntly, North Island, New Zealand. The chronology has been approximately dated to within the period 3,500 B.P. to 3,000 B.P. by radiocarbon dating. This is the first sub-fossil New Zealand chronology, and shows the potential for the formation of a long chronology from the present back over several millenia. The applications of this chronology and its possible extensions include radiocarbon calibration for the Southern Hemisphere, and climatic reconstructions based on ring-widths. It will also assist interpretation of the history of the Waikato Valley over the last few millenia

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. Chronologic and actinically induced aging in human facial skin

    International Nuclear Information System (INIS)

    Clinical and histologic stigmata of aging are much more prominent in habitually sun-exposed skin than in sun-protected skin, but other possible manifestations of actinically induced aging are almost unexplored. We have examined the interrelation of chronologic and actinic aging using paired preauricular (sun-exposed) and postauricular (sun-protected) skin specimens. Keratinocyte cultures derived from sun-exposed skin consistently had a shorter in vitro lifespan but increased plating efficiency compared with cultures derived from adjacent sun-protected skin of the same individual, confirming a previous study of different paired body sites. Electron microscopic histologic sections revealed focal abnormalities of keratinocyte proliferation and alignment in vitro especially in those cultures derived from sun-exposed skin and decreased intercellular contact in stratified colonies at late passage, regardless of donor site. One-micron histologic sections of the original biopsy specimens revealed no striking site-related keratinocyte alterations, but sun-exposed specimens had fewer epidermal Langerhans cells (p less than 0.001), averaging approximately 50 percent the number in sun-protected skin, a possible exaggeration of the previously reported age-associated decrease in this cell population. These data suggest that sun exposure indeed accelerates aging by several criteria and that, regardless of mechanism, environmental factors may adversely affect the appearance and function of aging skin in ways amenable to experimental quantitation

  13. 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.

  14. 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.

  15. Impact Chronology of the Moon — Results from the Lunar Reconnaissance Orbiter Camera (LROC)

    Science.gov (United States)

    Hiesinger, H.; van der Bogert, C. H.; Pasckert, J. H.; Plescia, J. B.; Robinson, M. S.

    2016-05-01

    We present absolute model ages (AMAs) based on crater size-frequency distribution (CSFD) measurements for Copernicus, Tycho, North Ray, Cone, and Autolycus craters to test and possibly improve the lunar cratering chronology.

  16. The application of carbon-isotope measurements to dendro- and xylem-chronology

    International Nuclear Information System (INIS)

    We measured 14C/13C Ratio of the Teak. The 14C excess, which reflects the execution of the tropospheric nuclear tests, is stamped in the Teak trunk. In place of the annual rings this stamp can estimate the xylem-chronologies and more accurate growth rates of tropical trees which have no annual rings. And replacing the shot-pinning method we can estimate the growing period in an annual ring formed especially in 1963-1966, when the 14C concentration in the tropospheric air changes dramatically. And we measured 14C-chronologies of the annual rings of O-Hinoki, 14C-chronologies agree well with dendrochronologies for the past 600 years. And the 14C chronologies support more determinative cross-dating of the archaeological samples. (author)

  17. Comparison of Varve and 14C Chronologies from Steel Lake, Minnesota, USA

    Energy Technology Data Exchange (ETDEWEB)

    Tian, J; Brown, T A; Hu, F S

    2004-12-29

    Annually laminated sediments (varves) offer an effective means of acquiring high-quality paleoenvironmental records. However, the strength of a varve chronology can be compromised by a number of factors, such as missing varves, ambiguous laminations, and human counting error. We assess the quality of a varve chronology for the last three millennia from Steel Lake, Minnesota, through comparisons with nine AMS {sup 14}C dates on terrestrial plant macrofossils from the same core. These comparisons revealed an overall 8.4% discrepancy, primarily because of missing/uncountable varves within two stratigraphic intervals characterized by low carbonate concentrations and obscure laminations. Application of appropriate correction factors to these two intervals results in excellent agreement between the varve and {sup 14}C chronologies. These results, together with other varve studies, demonstrate that an independent age-determination method, such as {sup 14}C dating, is usually necessary to verify, and potentially correct, varve chronologies.

  18. Deciphering Solar System Chronology with Lunar In-situ Dating: The MARE Discovery Mission

    Science.gov (United States)

    Anderson, F. S.; Draper, D.; Christensen, P. R.; Olansen, J.; Devolites, J.; Harris, W.; Whitaker, T. J.; Levine, J.

    2015-10-01

    We have proposed a discovery mission called the Moon Age and Regolith Explorer (MARE) that will land southwest of the Aristarchus Plateau, providing new measurements of age and petrology, addressing major questions of lunar and solar system chronology.

  19. 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.

  20. 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.

  1. 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.

  2. Luminescence Chronology Studies of a SAFOD Phase III Core Sample

    Science.gov (United States)

    Spencer, J. Q.; Hadizadeh, J.; Gratier, J.; Doan, M.

    2013-12-01

    This study is investigating the use of thermoluminescence (TL) and optically stimulated luminescence (OSL) phenomena to directly date the formation of discreet deformation microstructures present in core samples of fault gouge retrieved from the San Andreas Fault Observatory at Depth (SAFOD). Presently temporal information can only be provided by relative association via cross-cutting relationships. Absolute chronology of gouge fabric development will enable differentiation of microstructural components or domains that have developed at different deformation rates. Such data will lead to a better understanding of the fault processes of the San Andreas, and methods developed will be readily applicable to other active earthquake zones. Earlier luminescence studies were conducted on polymineral and K-feldspar from a small cube-shaped (~2.3x1.9x1.6 cm) fault gouge sample of San Andreas Fault Observatory at Depth (SAFOD) core from E11 (Hole E, Run 1, Section 2). These initial studies indicate (i) the thermal and radiation history of the mineral lattice can be assessed with TL, (ii) trap resetting is evident in both TL and infrared stimulated luminescence (IRSL) data, (iii) a small charge-trapping window between drill hole ambient temperature of ~112°C and higher energy lattice excitation via rupture events is evident in TL data from ~300-400°C, (iv) IRSL data have low natural intensity but good luminescence characteristics, and (v) single-aliquot regenerative-dose (SAR) IRSL equivalent dose (De) data have high over-dispersion but demonstrate ages ranging from decades to centuries may be measured. In addition to aspects of the above findings, this work will present further investigation of the relationship between TL and IRSL data, and effect of pulsed-irradiation in SAR protocols to mimic natural radiation dose at ambient temperature conditions at SAFOD core depth.

  3. The relationship between dental age, bone age and chronological age in underweight children

    OpenAIRE

    Vinod Kumar; Karthik Venkataraghavan; Ramesh Krishnan; Kavitha Patil; Karishma Munoli; Sandhya Karthik

    2013-01-01

    Background and Objective: The knowledge of bone age and dental age is of great importance for pediatrician and pediatric dentist. It is essential for a pediatric dentist to formulate treatment plan and it is a source of complementary information for pediatrician. There are few studies, which showed the relationship between dental age, bone age and chronological age in underweight children. Therefore, objective of this study was to determine and compare dental age, bone age and chronological a...

  4. The early Neolithic Volling site of Kildevang : its chronology and intra-spacial organisation

    OpenAIRE

    Ravn, Mads

    2011-01-01

    Due to the lack of large undisturbed sites, questions relating to the early Neolithic I (ENI) transition in Scandinavia, 6,000 years ago, reapeatedly get caught up in discussions of chronology and the nature of the fragmentary and regionalized source material. This paper presents an uncontaminated ENI Volling site in Eastern Jutland, Denmark, dating to around 3800 cal BC. It outlines a high-resolution ceramics chronology by combining stylistic elements with combinations of other finds. With 3...

  5. 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...

  6. 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 ...

  7. Time and narrative in economic geography

    OpenAIRE

    Curry, M; Barnes, T.

    1988-01-01

    There are two types of dynamic models found within economic geography -- the statistical and the causal. Both rest on a view of time which is based upon chronology and sequence. It is argued, however, that a chronological and sequential view of time is inadequate to comprehend the nature of economic behaviour, Instead, it is suggested that economic geographers begin thinking about time from the perspective of narrative.

  8. 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.

  9. Chronology and stratigraphy of Late Quaternary sediments in the Konya Basin, Turkey: Results from the KOPAL Project

    Science.gov (United States)

    Roberts, N.; Black, S.; Boyer, P.; Eastwood, W. J.; Griffiths, H. I.; Lamb, H. F.; Leng, M. J.; Parish, R.; Reed, J. M.; Twigg, D.; Yiǧitbaşioǧlu, H.

    1999-04-01

    The Late Quaternary environmental history of the Konya plain, in south central Turkey, is used to examine sediment facies changes in a shallow non-outlet basin which has experienced major climatically driven changes in lake extent. Two principal types of sedimentary archive are used to reconstruct a palaeoenvironmental record, namely alluvial sequences on the Çarşamba alluvial fan and sediments from residual lakes. The latter have been used to investigate broader climatic and vegetational histories via palaeolimnological techniques including pollen, diatom and stable isotope analysis. These changes are dated here by radiometric techniques including radiocarbon (AMS and conventional), OSL, and U-Th. Chronological agreement is generally good between the different dating techniques, although typically there is greatly reduced precision beyond ca. 25 ka. Lake sediment cores investigated have basal ages beyond the range of 14C dating, but contain hiatuses as a result of subsequent alternation between phases of lacustrine sedimentation and aeolian deflation. In contrast to most deepwater non-outlet lake systems, the Konya basin may have been occupied by a single extensive lake for as little as 10% of Late Quaternary time, mainly around the time of the LGM. This lake highstand was followed by an important arid interval. In the absence of unbroken chronostratigraphic sequences, palaeohydrological investigation of shallow non-outlet lakes may require analysis of basin-wide changes in sedimentation rather than reliance on single core records. Stratigraphic continuity in such sedimentary environments cannot be assumed, and requires independent chronological control through radiometric dating.

  10. Potential and limits of luminescence dating for establishing late-Holocene cyclone and tsunami chronologies

    Science.gov (United States)

    Brill, Dominik; May, Simon Matthias; Jankaew, Kruawun; Engel, Max; Brückner, Helmut

    2014-05-01

    Long-term recurrence intervals of coastal hazards such as tropical cyclones and tsunamis can be reconstructed on the basis of geological evidence of prehistoric events. These geological records have the potential to extend the period under observation beyond historical time scales. In addition to radiocarbon datings, optically stimulated luminescence (OSL) dating is used for the establishment of late-Holocene event chronologies. Here we discuss the potential and limits of applying OSL to sandy storm and tsunami deposits based on case studies from SW Thailand and NW Australia, where quartz luminescence properties (i.e., high sensitivity, thermally stable signal components dominated by the easily bleachable fast component, no mineralogical impurities) are favourable. Potential uncertainties and age offsets due to (i) incomplete signal resetting and (ii) spatial and temporal variations of dose rates that are supposed to be characteristic for deposits of coastal flooding events are evaluated. Incomplete bleaching of the OSL signal is evident in most deposits but can be corrected by statistical analysis of small aliquots or single grains using the minimum age model. Although the dating of modern analogues such as deposits from the 2004 Indian Ocean Tsunami revealed residuals, these uncertainties are insignificant compared to the respective local recurrence intervals. Further potential uncertainties arise from the complex coastal stratigraphies recording tsunami and cyclone deposits, such as variations between peat layers and sand sheets as well as differing concentrations of heavy minerals, but are comparably small if the geometry of different strata is adequately addressed. In contrast, errors introduced by temporal variations of environmental radiation fields may be much more significant. Especially changing water contents or radioactive disequilibria due to element mobility in marine carbonates are frequent in coastal settings and may lead to large uncertainties

  11. 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.

  12. 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

  13. 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...

  14. 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.

  15. 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

  16. 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.

  17. 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)

  18. The age of three Middle Palaeolithic sites: Single-grain optically stimulated luminescence chronologies for Pech de l'Azé I, II and IV in France.

    Science.gov (United States)

    Jacobs, Zenobia; Jankowski, Nathan R; Dibble, Harold L; Goldberg, Paul; McPherron, Shannon J P; Sandgathe, Dennis; Soressi, Marie

    2016-06-01

    Optically stimulated luminescence (OSL) measurements were made on individual, sand-sized grains of quartz from Middle Palaeolithic deposits at three sites (Pech de l'Azé I, II and IV) located close to one another in the Dordogne region of southwest France. We were able to calculate OSL ages for 69 samples collected from these three sites. These ages reveal periods of occupation between about 180 and 50 thousand years ago. Our single-grain OSL chronologies largely support previous age estimates obtained by thermoluminescence dating of burnt flints at Pech IV, electron spin resonance dating of tooth enamel at Pech I, II and IV and radiocarbon dating of bone at Pech I and IV, but provide a more complete picture due to the ubiquitous presence of sand-sized quartz grains used in OSL dating. These complete chronologies for the three sites have allowed us to compare the single-grain ages for similar lithic assemblages among the three sites, to test the correlations among them previously proposed by Bordes in the 1970s, and to construct our own correlative chronological framework for the three sites. This shows that similar lithic assemblages occur at around the same time, and that where a lithic assemblage is unique to one or found at two of the Pech sites, there are no deposits of chronologically equivalent age at the other Pech site(s). We interpret this to mean that, at least for these Pech de l'Azé sites, the Mousterian variants show temporal ordering. Whether or not this conclusion applies to the wider region and beyond, the hypothesis that Mousterian industrial variation is temporally ordered cannot be refuted at this time. PMID:27260176

  19. 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

  20. Establishment of an absolute chronology for the 18th Egyptian Dynasty

    International Nuclear Information System (INIS)

    The establishment of an absolute chronology for Ancient Egypt is an ambition which has concentrated efforts of many scholars since the beginning of Egyptology. Thanks to historical and archaeological documents, a relative chronology of the kings has been built. Only some astrophysical points and synchronisms listed in texts (Greek and Egyptian sources) have given some ankle points which have led to some propositions of absolute chronology. At first, we will see how we can re-calculate some ankle points by using Sothic dating and modelling lunar dates with a Bayesian approach. Then, radiocarbon measurements have been done at Laboratoire de Mesure du Carbone 14 (CEA Saclay) on Egyptian short life materials like plants or twigs. These objects come from the Louvre Museum and are attributed to a particular reign and a precise period. With a Bayesian approach, these analyses have been combined with the known succession and length of the reign. Besides, Sothic and lunar dates have been incorporated as a prior in the model. It has led to propose an absolute chronology for the 18th dynasty. Finally, we will discuss the agreement between our results and archaeological evidence and will see if this chronology can highlight points where Egyptologists disagree. (author)

  1. 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.

  2. 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.

  3. Thirty years together: A chronology of U.S.-Soviet space cooperation

    Science.gov (United States)

    Portree, David S. F.

    1993-01-01

    The chronology covers 30 years of cooperation between the U.S. and the Soviet Union (and its successor, the Commonwealth of Independent States, of which the Russian Federation is the leading space power). It tracks successful cooperative projects and failed attempts at space cooperation. Included are the Dryden-Blagonravov talks; the UN Space Treaties; the Apollo Soyuz Test Project; COSPAS-SARSAT; the abortive Shuttle-Salyut discussions; widespread calls for joint manned and unmanned exploration of Mars; conjectural plans to use Energia and other Russian space hardware in ambitious future joint missions; and contemporary plans involving the U.S. Shuttle, Russian Mir, and Soyuz-TM. The chronology also includes events not directly related to space cooperation to provide context. A bibliography lists works and individuals consulted in compiling the chronology, plus works not used but relevant to the topic of space cooperation.

  4. 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.

  5. Sequence of events from the onset to the demise of the Last Interglacial: Evaluating strengths and limitations of chronologies used in climatic archives

    Science.gov (United States)

    Govin, A.; Capron, E.; Tzedakis, P. C.; Verheyden, S.; Ghaleb, B.; Hillaire-Marcel, C.; St-Onge, G.; Stoner, J. S.; Bassinot, F.; Bazin, L.; Blunier, T.; Combourieu-Nebout, N.; El Ouahabi, A.; Genty, D.; Gersonde, R.; Jimenez-Amat, P.; Landais, A.; Martrat, B.; Masson-Delmotte, V.; Parrenin, F.; Seidenkrantz, M.-S.; Veres, D.; Waelbroeck, C.; Zahn, R.

    2015-12-01

    The Last Interglacial (LIG) represents an invaluable case study to investigate the response of components of the Earth system to global warming. However, the scarcity of absolute age constraints in most archives leads to extensive use of various stratigraphic alignments to different reference chronologies. This feature sets limitations to the accuracy of the stratigraphic assignment of the climatic sequence of events across the globe during the LIG. Here, we review the strengths and limitations of the methods that are commonly used to date or develop chronologies in various climatic archives for the time span (˜140-100 ka) encompassing the penultimate deglaciation, the LIG and the glacial inception. Climatic hypotheses underlying record alignment strategies and the interpretation of tracers are explicitly described. Quantitative estimates of the associated absolute and relative age uncertainties are provided. Recommendations are subsequently formulated on how best to define absolute and relative chronologies. Future climato-stratigraphic alignments should provide (1) a clear statement of climate hypotheses involved, (2) a detailed understanding of environmental parameters controlling selected tracers and (3) a careful evaluation of the synchronicity of aligned paleoclimatic records. We underscore the need to (1) systematically report quantitative estimates of relative and absolute age uncertainties, (2) assess the coherence of chronologies when comparing different records, and (3) integrate these uncertainties in paleoclimatic interpretations and comparisons with climate simulations. Finally, we provide a sequence of major climatic events with associated age uncertainties for the period 140-105 ka, which should serve as a new benchmark to disentangle mechanisms of the Earth system's response to orbital forcing and evaluate transient climate simulations.

  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. DNA damage markers in dermal fibroblasts in vitro reflect chronological donor age

    DEFF Research Database (Denmark)

    Waaijer, Mariëtte E C; Croco, Eleonora; Westendorp, Rudi G J; Slagboom, P Eline; Sedivy, John M; Lorenzini, Antonello; Maier, Andrea B

    2016-01-01

    The aging process is accompanied by an accumulation of cellular damage, which compromises the viability and function of cells and tissues. We aim to further explore the association between in vitro DNA damage markers and the chronological age of the donor, as well as long-lived family membership...... damage markers and long-lived family membership or cardiovascular disease. Results were comparable when fibroblasts were stressed in vitro with rotenone. In conclusion, we found that DNA damage foci of cultured fibroblasts are significantly associated with the chronological age, but not biological age...

  8. Lead concentration and isotope chronology in two coastal environments in Western and South East Asia

    Science.gov (United States)

    Carrasco, G. G.; Chen, M.; Boyle, E. A.; Zhao, N.; Nurhati, I. S.; Gevao, B.; al Ghadban, A.; Switzer, A.; Lee, J. M.

    2014-12-01

    Lead is a trace metal that is closely related to anthropogenic activity, mainly via leaded gasoline and coal combustion. The study of lead concentrations and isotopes in seawater, sediments, corals and aerosols allows for a systematic look at its sources and their time evolution in a natural environment. We will discuss results from two projects in Western and South East Asia, regions that have seen dramatic socio-economical changes over the past half-century that may have left environmental signals. These results highlight the usefulness of the method, indicate the degree of complexity of these systems, and point to the need for a continuous monitoring of anthropogenic trace metals in the small-medium coastal scale to be able to asses the larger scale effects of human activity. On the one hand, coastal Kuwait is heavily influenced by the Shat al-Arab river and shows a clear anthropogenic signature from Kuwait city. A mix of two sources can be tracked through the coral and sediment chronological records, with Pb206/Pb207 ratios (1.202 and 1.151) that approach the suspected source values (1.21 and 1.12) and eliminate the possibility of other sources. Through a wide sediment geographic distribution, the strength of the anthropogenic signature is modulated. On the other hand, Singapore offers a more complex system, where an apparent mix of two sources (extreme isotope ratios 1.215 and ~1.14) occurs also, but where either an unresolved potentially important third source (isotope ratio ~1.18), or an isotope exchange process should be invoked. The sediment and coral records allows us to track the changes through time; however, there seems to be incongruence with the aerosol isotope record. Further potential sources are being explored currently and will be discussed.

  9. 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.

  10. 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.

  11. 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

    combined efforts confirm two major glacial advances in the Cordillera de Cochabamba, which took place during the global LGM and during the Lateglacial. However, their relative chronologies and sedimentary interpretation indicate that the maximum extent of glaciation at Huara Loma was reached during humid Lateglacial times whereas conditions during the LGM were probably too dry.

  12. 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...

  13. 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

  14. 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.

  15. 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...

  16. 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.; Koerner, R. M.; Johnsen, Sigfus Johann; Andersen, Katrine Krogh; Dahl-Jensen, Dorthe; Rasmussen, Sune Olander; Steffensen, Jørgen Peder; Svensson, Anders

    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...

  17. 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.; Nordlund, Åke; Wielandt, Daniel Kim Peel; Ivanova, Marina A.

    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 and...

  18. You Can't Play That: A Selective Chronology of Banned Music: 1850-1991.

    Science.gov (United States)

    Volz, Edward J.

    1991-01-01

    Discussion of music censorship provides a chronology of banned music from 1850 to the present. Highlights include reasons for music censorship, including lyrics that concern politics, sex, drugs, or death; rewriting song lyrics; radio air play versus sales; warning labels; First Amendment principles; and suggestions to defuse censorship in…

  19. Temperature-sensitive Tien Shan tree ring chronologies show multi-centennial growth trends

    Energy Technology Data Exchange (ETDEWEB)

    Esper, J. [Swiss Federal Research Institute WSL, Zuercherstrasse 111, 8903 Birmensdorf (Switzerland); Shiyatov, S.G.; Mazepa, V.S. [Institute of Plant and Animal Ecology, Ural Division of Russian Academy of Sciences, 8 Marta Street 202, 620144 Ekaterinburg (Russian Federation); Wilson, R.J.S. [School of GeoSciences, Grant Institute, Edinburgh University, West Mains Road, Edinburgh EH9 3JW (United Kingdom); Graybill, D.A.; Funkhouser, G. [Laboratory of Tree-Ring Research, University of Arizona, Tucson, Arizona 85721 (United States)

    2003-12-01

    Two millennia-length juniper ring width chronologies, processed to preserve multi-centennial growth trends, are presented for the Alai Range of the western Tien Shan in Kirghizia. The chronologies average the information from seven near-timberline sampling sites, and likely reflect summer temperature variation. For comparison, chronologies are also built using standard dendrochronological techniques. We briefly discuss some qualities of these ''inter-decadal'' records, and show the low frequency components removed by the standardization process include a long-term negative trend in the first half of the last millennium and a long-term positive trend since about AD 1800. The multi-centennial scale Alai Range chronologies, where these trends are retained, are both systematically biased (but in an opposite sense) in their low frequency domains. Nevertheless, they represent the best constraints and estimates of long-term summer temperature variation, and reflect the Medieval Warm Period, the Little Ice Age, and a period of warming since about the middle of the nineteenth century. (orig.)

  20. 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...

  1. Time Functions as Utilities

    Science.gov (United States)

    Minguzzi, E.

    2010-09-01

    Every time function on spacetime gives a (continuous) total preordering of the spacetime events which respects the notion of causal precedence. The problem of the existence of a (semi-)time function on spacetime and the problem of recovering the causal structure starting from the set of time functions are studied. It is pointed out that these problems have an analog in the field of microeconomics known as utility theory. In a chronological spacetime the semi-time functions correspond to the utilities for the chronological relation, while in a K-causal (stably causal) spacetime the time functions correspond to the utilities for the K + relation (Seifert’s relation). By exploiting this analogy, we are able to import some mathematical results, most notably Peleg’s and Levin’s theorems, to the spacetime framework. As a consequence, we prove that a K-causal (i.e. stably causal) spacetime admits a time function and that the time or temporal functions can be used to recover the K + (or Seifert) relation which indeed turns out to be the intersection of the time or temporal orderings. This result tells us in which circumstances it is possible to recover the chronological or causal relation starting from the set of time or temporal functions allowed by the spacetime. Moreover, it is proved that a chronological spacetime in which the closure of the causal relation is transitive (for instance a reflective spacetime) admits a semi-time function. Along the way a new proof avoiding smoothing techniques is given that the existence of a time function implies stable causality, and a new short proof of the equivalence between K-causality and stable causality is given which takes advantage of Levin’s theorem and smoothing techniques.

  2. WD2014: A new reference chronology for ice cores from Antarctica?

    Science.gov (United States)

    Sigl, Michael; McConnell, Joseph R.; Winstrup, Mai; Fudge, Taylor J.; Cole-Dai, Jihong; Ferris, David; Taylor, Kendrick; Buizert, Christo; Rhodes, Rachael; McGwire, Ken; Welten, Kees C.; Woodruff, Thomas E.; Dunbar, Nelia; Iverson, Nels; Maselli, Olivia J.; Pasteris, Daniel R.; Muscheler, Raimund

    2015-04-01

    Here we present a chronology (WD2014) for the upper part (0-2850 m, 31.2 ka BP) of the West Antarctic Ice Sheet (WAIS)-Divide ice core which is based on layer counting of distinctive annual cycles preserved in the elemental, chemical and electrical conductivity records. These cycles are caused by the seasonally varying impurity concentrations in snowfall reflecting source strength of emissions, transport and deposition efficiency. A new ice core chronology has been developed using manual interpretation as well as by using a layer detection algorithm based on Hidden Markov Models taking advantage of the large suite of sub-annually resolved and co-registered aerosol records from high-resolution continuous measurements. The age model is validated against the absolute dated radiocarbon calibration curve IntCal13 using ice-core Be-10 measurements for proxy synchronization. These records reveal an unprecedented accuracy of the new ice core chronology since the Last Glacial Maximum. The new chronology can become a reference chronology for ice cores with synchronization to other ice cores achievable through the unique high-resolution sulfur record indicating hundreds of volcanic signals common to many other deep ice cores in Antarctica. A developing tephra framework for ice cores from West Antarctica will allow to better integrating Antarctic ice cores and the marine and terrestrial records from the southern hemisphere in the future, thus gaining a detailed chronologic picture of climatic changes and environmental consequences for the region over the past 31,000 years. This southern hemisphere perspective is a fundamental step in developing a detailed global understanding of the effects of past climate changes, and its implications for the future. Due to a small ice-age gas-age difference (delta-age) at WAIS Divide - because of high annual snowfall rates at this site - and a new high-resolution WAIS CH4 record, this new ice core chronology provides also independent

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

    Science.gov (United States)

    Jonker, Martijs J; Melis, Joost P M; Kuiper, Raoul V; van der Hoeven, Tessa V; Wackers, Paul F K; Robinson, Joke; van der Horst, Gijsbertus T J; Dollé, Martijn E T; Vijg, Jan; Breit, Timo M; Hoeijmakers, Jan H J; van Steeg, Harry

    2013-10-01

    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 life span (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 intraorgan 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 intraindividual (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 that 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. Preliminary study of the chronology of the sedimentation process in lakes

    International Nuclear Information System (INIS)

    The soil erosion accelerated which produces the presence of sediment in rivers is one of the main environmental problems and represents a challenge for the sustainable use of soil and water resources. The problems associated with the increased sediments production are mainly related to the rivers siltation, reduced storage capacity of dams and reservoirs and reduction in the quality of aquatic environment. Thus, further information on sedimentation rates in lakes and reservoirs are required, as a parameter for estimating the chronology of production rates of sediment. Therefore, methods to establish the chronology of recent sediments are central base for such research. The cesium-137 is an artificial radionuclide with a half life of 30.2 years, inserted in the environment through the 'fallout' radioactive between the 1950's and 1970's, with two predominant peaks of deposition in 1959 and 1964. The basis for using the cesium-137 in this context (chronology of sediments) is that the cesium-137 is rapidly and strongly adsorbed to fine particles of soil and its distribution in the sediment profile directly reflects the chronology of sediment deposition. The purpose of this work is to use the cesium-137 profile in lake sediments to assess the history of deposition and to obtain information about the erosive process. For this, lake sediments of a mini-hydroelectric power plant built in the 1940's in the city of Londrina-PR were analyzed, showing that cesium-137 can be used as a source of data for chronological assessment of erosive processes occurring in the vicinity of the lake. (author)

  5. Preliminary study of the chronology of the sedimentation process in lakes

    Energy Technology Data Exchange (ETDEWEB)

    Patrocinio Junior, Antonio C.; Andrello, Avacir C., E-mail: juninhoska@hotmail.co, E-mail: acandrello@uel.b [Universidade Estadual de Londrina, PR (Brazil). Dept. de Fisica

    2009-07-01

    The soil erosion accelerated which produces the presence of sediment in rivers is one of the main environmental problems and represents a challenge for the sustainable use of soil and water resources. The problems associated with the increased sediments production are mainly related to the rivers siltation, reduced storage capacity of dams and reservoirs and reduction in the quality of aquatic environment. Thus, further information on sedimentation rates in lakes and reservoirs are required, as a parameter for estimating the chronology of production rates of sediment. Therefore, methods to establish the chronology of recent sediments are central base for such research. The cesium-137 is an artificial radionuclide with a half life of 30.2 years, inserted in the environment through the 'fallout' radioactive between the 1950's and 1970's, with two predominant peaks of deposition in 1959 and 1964. The basis for using the cesium-137 in this context (chronology of sediments) is that the cesium-137 is rapidly and strongly adsorbed to fine particles of soil and its distribution in the sediment profile directly reflects the chronology of sediment deposition. The purpose of this work is to use the cesium-137 profile in lake sediments to assess the history of deposition and to obtain information about the erosive process. For this, lake sediments of a mini-hydroelectric power plant built in the 1940's in the city of Londrina-PR were analyzed, showing that cesium-137 can be used as a source of data for chronological assessment of erosive processes occurring in the vicinity of the lake. (author)

  6. 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 ...

  7. 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

  8. Chronology of endocrine differentiation and beta-cell neogenesis [Review].

    Science.gov (United States)

    Miyatsuka, Takeshi

    2016-03-31

    Diabetes is a chronic and incurable disease, which results from absolute or relative insulin insufficiency. Therefore, pancreatic beta cells, which are the only type of cell that expresses insulin, is considered to be a potential target for the cure of diabetes. Although the findings regarding beta-cell neogenesis during pancreas development have been exploited to induce insulin-producing cells from non-beta cells, there are still many hurdles towards generating fully functional beta cells that can produce high levels of insulin and respond to physiological signals. To overcome these problems, a solid understanding of pancreas development and beta-cell formation is required, and several mouse models have been developed to reveal the unique features of each endocrine cell type at distinct developmental time points. Here I review our understanding of pancreas development and endocrine differentiation focusing on recent progresses in improving temporal cell labeling in vivo. PMID:26615757

  9. 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.

  10. 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

  11. Searching for Constraints on the Chronology of the Outer Solar System From Satellite Geophysics

    Science.gov (United States)

    Johnson, T.; Castillo-Rogez, J.; Matson, D.; Lunine, J.

    2007-08-01

    Recent astronomical observations suggest that the lifetime of gas and dust sufficient for making giant planets around Sun-like stars may be typically only two to five million years. Thus if short-lived radioactive isotopes (SLRI) with half-lives of 10 My were present in the circumstellar disk, they would be included in any planets formed. These isotopes would supply heat as they decayed. The challenge is to search for observations that test the validity of this scenario. In the Solar System, we believe that models of medium-sized satellites can be used for this purpose. Initial results suggest that they can also yield constraints on the time of formation and chronology of the outer Solar system. We will address the reasons supporting this suggestion, status of our understanding of this problem, and the outstanding issues. Small satellites in the outer solar system (less than 1000 km in radius) provide the right conditions for the heat from SLRI to express itself in terms of observable geophysical properties. Their temperatures at accretion are low (less than 100 K), and they gain a negligible amount of heat during accretion compared to the larger icy satellites. It is difficult to heat them with long-lived radioactive isotopes (LLRI) since the time scale required for LLRI decay to heat the interior up to water ice creep temperature is much longer than the time scale for these objects to cool. Whether or not tidal dissipation is a significant heat source is a crucial issue. We have been searching for evidence that SLRI were available in the early, outer Solar system, using coupled thermophysical-dynamical modeling of the icy satellites. The SLRI that are most significant for modeling the thermal evolution of Solar system objects are 26Al and 60Fe. We use the CAI formation date as the reference time for our satellite models discussed below and the initial concentrations of 26Al and 60Fe have been defined for that time. If SLRI are present, then the main parameter

  12. Development of a rainfall sensitive tree-ring chronology in Zimbabwe

    Energy Technology Data Exchange (ETDEWEB)

    Stahle, D.W.; Cleaveland, M.K. [Univ. of Arkansas, Fayetteville, AK (United States); Nicholson, S.E. [Florida State Univ., Tallahassee, FL (United States)] [and others

    1997-11-01

    This paper reports the discovery of annual tree ring formation in two species of trees in Zimbabwe and describes their paleoclimatic reconstruction potential. Due to the strong influence of El Nino-Southern Oscillation on the climate and crop yields of Zimbabwe and surrenting areas, and the rarity of annual tree ring chronologies in the tropics, the discovery of climatically sensitive growth rings is extremely significant. In particular, the Pterocarpus angolensis shows a strong correlation between the derived tree ring chronology and regional rainfall amounts. Based on sampling at the Sikumi Forest, it is speculated that P. angolensis may routinely achieve over 200 years in age. Four lines of evidence are identified which indicate that the semi-ring porous growth bands in P. angolensis are exactly annual growth rings. 18 refs., 3 figs.

  13. 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

  14. Fine resolution AMS 14C chronology for Lunette-Lake sediment sequences, Lake Bolac, Victoria

    International Nuclear Information System (INIS)

    This study aims to provide a fine-resolution chronology for lake sediment records from Lakes Bolac and Turangmoroke, located within the drier part of the Western Plains, Victoria. These lakes are expected to be sensitive to subtle climate and vegetation variability and have long been recognised as archaeologically rich, bearing stone tools, hearth and other cultural materials dated to the late Pleistocene (Horton, 1984; former Victorian Aboriginal Survey, unpublished data). Fine-resolution chronological control has rarely been attempted in this sedimentary and (semi-arid) climatic context owing to the paucity of material available for conventional 14C dating. However, pollen and microscopic charcoal in the lake sediments at Bolac and Turangmoroke are suitable for AMS age determination with the most important sedimentary section well within the range of 14C making them ideal records for such a study. Recent dating results, which have substantially increased chronostratigraphic interpretation of concurrent palaeoecological and sedimentological work in progress, are presented

  15. The mineralogical, chemical, and chronological characteristics of the crystalline Apollo 16 impact melt rocks

    Science.gov (United States)

    Reimold, W. U.; Reimold, J. N.

    1984-01-01

    A comparative review of mineralogical, chemical, and chronological data on crystalline Apollo 16 impact melt rocks is presented. The use of such data to identify distinct impact melt complex is discussed, and 22 distinct impact melt bodies are identified. The recently detected group of feldspathic microporphyritic (FM) melt rocks was tested for chemical and isotopic homogeneity; instrumental neutron activation analysis and new Rb-Sr isotopic whole rock data indicate that FMs were probably not derived from a single impact melt sheet, but might be representative of the Descartes basement. Stratigraphical and chronological concepts for the geological development of the landing site are discussed, and a model is presented for the formation of the Cayley Plains and the Descartes formation.

  16. 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.

  17. Fine resolution AMS {sup 14}C chronology for Lunette-Lake sediment sequences, Lake Bolac, Victoria

    Energy Technology Data Exchange (ETDEWEB)

    Cook, E. [Monash University, Clayton, VIC (Australia). Centre for Palynology and Palaeoecology, Department of Geography and Environmental Science

    1998-12-31

    This study aims to provide a fine-resolution chronology for lake sediment records from Lakes Bolac and Turangmoroke, located within the drier part of the Western Plains, Victoria. These lakes are expected to be sensitive to subtle climate and vegetation variability and have long been recognised as archaeologically rich, bearing stone tools, hearth and other cultural materials dated to the late Pleistocene (Horton, 1984; former Victorian Aboriginal Survey, unpublished data). Fine-resolution chronological control has rarely been attempted in this sedimentary and (semi-arid) climatic context owing to the paucity of material available for conventional {sup 14}C dating. However, pollen and microscopic charcoal in the lake sediments at Bolac and Turangmoroke are suitable for AMS age determination with the most important sedimentary section well within the range of {sup 14}C making them ideal records for such a study. Recent dating results, which have substantially increased chronostratigraphic interpretation of concurrent palaeoecological and sedimentological work in progress, are presented

  18. 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

  19. 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.

  20. Magnetic studies of erosion in a Scottish lake catchment. 1. Core chronology and correlation

    International Nuclear Information System (INIS)

    Magnetic susceptibility, 210Pb, 137Cs, 14C, and paleomagnetic secular variation are used to establish the chronology of sedimentation in a set of cores from Loch Frisa in western Scotland. The 14C dates obtained are not compatible with the chronology derived from all the other techniques and this is ascribed to inwash of old particulate carbon from the watershed. Central cores show little evidence of changes in sedimentation rate over the last 150 years whereas marginal cores contain evidence of major increases arising from ploughing and from drainage associated with catchment afforestation since 1935. The results illustrate the value of a multiple core approach to sedimentation and erosion studies even where complex lake morphometry precludes calculation of sediment budgets

  1. 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.

  2. 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.

  3. A Study of Correlation of Various Growth Indicators with Chronological Age

    OpenAIRE

    Singh, Sarabjeet; Sandhu, Navreet; Puri, Taruna; Gulati, Ritika; Kashyap, Rita

    2015-01-01

    ABSTRACT Introduction: The aim of this study was to assess the relationship of chronological age with cervical vertebrae skeletal maturation, frontal sinus width and antegonial notch depth and a correlation, if any, among the three variables. Materials and methods: The samples were derived from lateral cephalometric radiographs of 80 subjects (40 males, 40 females; age range: 10 to 19 years). Cervical vertebral development was evaluated by the method of Hassel and Farman, frontal sinus width ...

  4. 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.

  5. 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.

  6. 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...

  7. 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.

  8. 60Fe-60Ni chronology of core formation in Mars

    CERN Document Server

    Tang, Haolan

    2014-01-01

    The timescales of accretion, core formation, and magmatic differentiation in planetary bodies can be constrained using extinct radionuclide systems. Experiments have shown that Ni becomes more siderophile with decreasing pressure, which is reflected in the progressively higher Fe/Ni ratios in the mantles of Earth, Mars and Vesta. Mars formed rapidly and its mantle has a high Fe/Ni ratio, so the 60Fe-60Ni decay system (t1/2=2.62 Myr) is well suited to establish the timescale of core formation in this object. We report new measurements of 60Ni/58Ni ratios in bulk SNC/martian (Shergotty-Nakhla-Chassigny) meteorites and chondrites. The difference in {\\epsilon}60Ni values between SNC meteorites and the building blocks of Mars assumed to be chondritic (55 % ordinary chondrites +45% enstatite chondrites) is +0.028+/-0.023 (95% confidence interval). Using a model of growth of planetary embryo, this translates into a time for Mars to have reached ~44 % of its present size of 1.9(-0.8)(+1.7) Myr with a strict lower lim...

  9. Comparison of the glacial chronology of Eastern Baffin Island, East Greenland and Camp century accumulation record

    DEFF Research Database (Denmark)

    Andrews, John; Funder, Svend Visby; Hjort, Chritian; Imbrie, John

    1974-01-01

    Independently derived glacial chronologies from eastern Baffin Island, Canadian Arctic, and from East Greenland show essentially similar glaciologic trends that arc notably different from the response of the southern margins of the Laurentide and FCllnoscandia Ice Sheets. The critical aspe~ts of...... both chronologies and the related extcn t of the ice sheets are (1) an early and maximum glacial stade, during the early phase of the last glaciation, reaching its peak abqut 100,000 to 75,000 yr ago; (2) an in terstadial about .70,000 n.p.; (3) an ice advance peaking about 45,000 yr ago; (4) an...... interval about 40,000 to 11,000 yr ago of restricted ice extent; and (5) a late glacial sladial belween 11,000 and 8,000 B.P. This record shows basic agreement with a chronology of snow accumulation at the Camp Century ice core site based on a revised chronostratigraphic interpretation. Fluctuations in sea...

  10. Comparison among dental, skeletal and chronological development in HIV-positive children: a radiographic study.

    Science.gov (United States)

    Holderbaum, Rejane Maria; Veeck, Elaine Bauer; Oliveira, Helena Willhelm; Silva, Carmem Lúcia da; Fernandes, Angela

    2005-01-01

    The goal of this study was to evaluate skeletal, dental and chronological development in an HIV-positive group of children, as compared with a control group, during a four-year period. Panoramic radiographs and hand and wrist radiographs of 60 children were taken. The children, of both sexes, aged 5 years and 2 months to 15 years and 5 months, were selected as follows: 30 HIV-positive volunteers who had acquired the disease vertically, and 30 volunteers who did not present the HIV infection or any other systemic disease. All radiographs were technically standardized and analyzed according to criteria established by Nolla (dental age), Greulich and Pyle (bone age), and Eklöf and Ringertz (bone age). The results were submitted to Student's t-test at a 5% level of significance. Based on the comparison between the chronological age and the dental or the skeletal age, significant differences were observed between HIV-positive and HIV-negative children, both in 1999 and in 2003 (p dental ages compared with their chronological ages in 1999 and in 2003; and HIV-positive males, in 1999. PMID:16308610

  11. Chronology of mitochondrial and cellular events during skeletal muscle ischemia-reperfusion.

    Science.gov (United States)

    Paradis, Stéphanie; Charles, Anne-Laure; Meyer, Alain; Lejay, Anne; Scholey, James W; Chakfé, Nabil; Zoll, Joffrey; Geny, Bernard

    2016-06-01

    Peripheral artery disease (PAD) is a common circulatory disorder of the lower limb arteries that reduces functional capacity and quality of life of patients. Despite relatively effective available treatments, PAD is a serious public health issue associated with significant morbidity and mortality. Ischemia-reperfusion (I/R) cycles during PAD are responsible for insufficient oxygen supply, mitochondriopathy, free radical production, and inflammation and lead to events that contribute to myocyte death and remote organ failure. However, the chronology of mitochondrial and cellular events during the ischemic period and at the moment of reperfusion in skeletal muscle fibers has been poorly reviewed. Thus, after a review of the basal myocyte state and normal mitochondrial biology, we discuss the physiopathology of ischemia and reperfusion at the mitochondrial and cellular levels. First we describe the chronology of the deleterious biochemical and mitochondrial mechanisms activated by I/R. Then we discuss skeletal muscle I/R injury in the muscle environment, mitochondrial dynamics, and inflammation. A better understanding of the chronology of the events underlying I/R will allow us to identify key factors in the development of this pathology and point to suitable new therapies. Emerging data on mitochondrial dynamics should help identify new molecular and therapeutic targets and develop protective strategies against PAD. PMID:27076618

  12. 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

  13. Constraints on the use of anthropogenic radionuclide-derived chronologies for saltmarsh sediments

    International Nuclear Information System (INIS)

    Numerous studies have employed anthropogenic radionuclides deposited in accumulating sediments to derive chronologies for use in investigations of geomorphological processes and in reconstructing temporal trends in contaminant deposition. However, relatively few have interrogated their use in systems that erode as well as accrete sediment, or have addressed limitations in their applicability in systems that experience variable rates of accumulation. This paper examines the utility of Sellafield-derived radionuclides for reconstructing sedimentary processes in two contrasting saltmarsh systems in the south-west of Scotland. Sedimentation rates and patterns derived from the radionuclide chronologies are outlined and compared to results established through conventional geomorphological methods. The results confirm that the vertical distribution of anthropogenic radionuclides can be useful in determining sedimentation rates, but that these cannot always be used as indicators of contemporary processes, particularly where erosion is occurring. Their use is also limited unless profiles are obtained from spatially diverse geomorphological units. Integrating the use of chronologies with other independent methods secures more robust data for assessing both marsh sustainability and their longevity as radionuclide sinks

  14. Rethinking About Chronology Of Chichen Itza: By Thermoluminescence Dating Of Volcanic Glass.

    Science.gov (United States)

    Chung, H.; Gonzalez, P.; Ramirez, A.; Schaaf, P.; Lee, I.

    One of the most frequently recurring questions in archaeology concerns the age of the studied objects. To date, determining the chronology of the Puuc and Chichen Slate pottery of Chchen Itza, based on the stylistic change in the pottery, has been problematic. The Thermoluminescence method of dating pottery was applied to samples of Chichen Itza, Yucatan, Mexico, which contain volcanic glass as temper. They were analyzed using the fine grain technique. The radisotopes that contribute to the accumulate annual dose in ceramic samples (40K, 238U, 232Th) were determined by means of Energy Dispersive X-ray Spectroscopy and Neutron Activation Analysis technique, while the artificial irradiation of the samples was carried out using 90Sr source beta radiation. We obtained results indicating the following dates; 875 ± 88; 1055 ± 85; 1063 ± 47, 1154 ± 76; 1110 ± 53, 1132 ± 69, 1221 ± 30, 1532 ± 26. The results demonstrate a chronological order of dates. Most results are in accordance with the established dates of Chichen Itza. However, Puuc and Chichen Slate did not show differences of 200 years as previously proposed, and there is evidence of an earlier period than those two pottery periods. This necessitates a reconsideration of the chronology of Chichen Itza.

  15. Geological reconnaissance and chronologic studies. Technical report No. 33

    International Nuclear Information System (INIS)

    There are several possible scenarios by which a radioactive waste storage facility in the unsaturated zone could be compromised; among them erosion, water table rise, or downward percolation of water. In order to assess these risks, the geologic and climatic events of the past few million years can be used to project the future of the unsaturated deposits. Geologic reconnaissance on and around the NTS was undertaken to identify specific evidence of depositional, erosional, and hydrologic events, as well as to develop an understanding of the timing of these events. Several kinds of evidence were noted and studied: layers or volcanic ash in the basin-fill sediments were discovered and dated at 11 to 5 m.y. old, showing the modern valleys and ranges are at least 11 m.y. old. Exposure of these ash layers by erosion has taken 5 m.y., implying that additional millions of years must pass before modern closed basins on the NTS are eroded. Detailed study of young sediments in Las Vegas Valley suggest that water tables stood at 926 m as recently as 14,000 y ago. To the northeast or the NTS, sediments in basin bottoms also reflect high water tables until about 7000 y ago, but sediments on the NTS proper do not show this effect during the last 700,000 y. The observed relation between erosion due to downwearing or mountain ranges and infilling of valleys suggests that these processes continue, only the uppermost parts of present alluvial fans will be eroded

  16. Improvements in the chronology, geochemistry and correlation techniques of tephra in Antarctic ice

    Science.gov (United States)

    Iverson, N. A.; Dunbar, N. W.; McIntosh, W. C.; Pearce, N. J.; Kyle, P. R.

    2013-12-01

    Visible and crypto tephra layers found in West Antarctic ice provide an excellent record of Antarctic volcanism over the past 100ka. Tephra layers are deposited almost instantaneously across wide areas creating horizons that, if found in several locations, provide 'pinning points' to adjust ice time scales that may otherwise be lacking detailed chronology. Individual tephra layers can have distinct chemical fingerprints allowing them to correlate over great distances. Advances in sample preparation, geochemical analyses (major and trace elements) of fine grained tephra and higher precision 40Ar/39Ar dating of young (South America). Combining ice core tephra with those exposed in blue ice areas provide more locations to correlate widespread eruptions. For example, a period of heightened eruptive activity at Mt. Berlin, West Antarctica between 24 and 28ka produced a set of tephra layers that are found in WDC06A and SDMA ice cores, as well as at a nearby blue ice area at Mt. Moulton (BIT-151 and BIT-152). Possible correlative tephra layers are found at ice ages of 26.4, 26.9 and 28.8ka in WDC06A and 26.5, 27.0, and 28.7ka in SDMA cores. The geochemical similarities of major elements in these layers mean that ongoing trace element analyses will be vital to decipher the sequence of events during this phase of activity at Mt. Berlin. Sample WDC06A-2767.117 (ice age of 28.6×1.0ka) appears to correlate to blue ice tephra BIT-152 and to tephra layer SDMA-5683 (ice age of 28.5ka). This tephra layer also appears to be present in blue ice at Mt. Terra Nova on Ross Island, 1400km away, suggesting that it may be a possible to link ice cores in East Antarctica (e.g. Talos Dome and Law Dome). The amount of feldspar in ice core tephra is typically too small to be directly dated by 40Ar/39Ar method, making it very important to geochemically correlate these layers to proximal deposits where more and larger feldspar can be sampled. The correlation of WDC06A-2767.117 to the coarse

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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.

  2. Station Blackout Initiated Event Chronology in LWR/HWR NPP

    International Nuclear Information System (INIS)

    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

  3. 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

  4. IMPACT OF PESTICIDES USED IN THE CULTURE OF THE VINE ON THE VIABILITY OF THE YEAST SACCHAROMYCES CEREVISIAE WINE IN CHRONOLOGICAL AGING

    Directory of Open Access Journals (Sweden)

    Alina Owsiak

    2015-02-01

    Full Text Available Pesticides, used in culture, may induce oxidative stress by stimulation of free radicals production, what may result in lipid peroxidation, proteome damage, changes in DNA and RNA structures and disturbance of total antioxidative capacity in organisms’ cells. In disturbances caused by increase synthesis ROS (reactive oxygen species or lack antioxidative defense that is in oxidative stress it is seen one of all causes of aging process. Chronological aging of baker’s and wine yeast Saccharomyces cerevisiae in liquid stationary culture is used as model of research on the aging process. As a result of aging changes take place in yeast cells which have physiological, genetic, metabolic and morphological character, what cause their death in consequence. Some scientists treat chronological yeast aging as analogy of fibroblasts aging of multicellular organisms, skeletal muscles or nerve cells. The aim of the experiment was to obtain the answer on question connected with toxicity effect two widely available pesticides in shape of trade preparation, used among other things in culture of grapevine Miedzian 50 WP (Cu 50WP and Siarkol Extra 80 WP (S 80WP on vitality of wine yeast in chronological aging. During research cells of wine yeast Tokay, which are used in production of white wines, and cells of Malaga strain, used in production of white and red wines, were applied. Yeast culture with pesticides supplementation in determined concentrations was conducted through seven days in YPG medium. At that time vitality of yeast cells was determined by the percentage of cells surviving, percentage of dead cells and culture density. Considerable influence on decreasing vitality of yeast cells in the process of aging showed S 80WP, what correlate with the increase of applied concentration in both example of Malaga and Tokay. Obtained results in application of Cu 50WP indicated lower toxicity in culture of both studied strains in comparison to the control. Our

  5. 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 ...

  6. Dental maturity as an indicator of chronological age: radiographic assessment of dental age in a brazilian population

    OpenAIRE

    Lucio Mitsuo Kurita; Alynne Vieira Menezes; Marcia Spinelli Casanova; Francisco Haiter-Neto

    2007-01-01

    Objective: The purpose of this investigation was to evaluate the applicability of the methods proposed by Nolla and by Nicodemo and colleagues for assessing dental age and its correlation to chronological age. Methods: Panoramic radiographs of 360 patients from the city of Fortaleza (CE, Brazil) aged 7-15 years were used to assess the associations between dental and chronological age. Data were submitted to statistical analysis using the BioEstat 2.0 (2000) software. Student-Neuman-Keuls test...

  7. 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...

  8. 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

    terrestrial planets, including Mars and possibly early Earth. The Moon holds a historic record of Galactic cosmic-ray intensity, solar wind composition and fluxes and composition of solids of any size in the region of the terrestrial planets. Some of this record has been deciphered. Secular mixing of the Sun was constrained by determining 3He/4He of solar wind helium stored in lunar fines and ancient breccias. For checking the presumed constancy of the impact rate over the past ≈3.1 Ga, samples of the youngest mare basalts would be needed for determining their radiometric ages. Radiometric dating and stratigraphy has revealed that many of the large basins on the near side of the Moon were created by impacts about 4.1 to 3.8 Ga ago. The apparent clustering of ages called "Late Heavy Bombardment (LHB)" is thought to result from migration of planets several 100 million years after their accretion. The bombardment, unexpectedly late in solar system history, must have had a devastating effect on the atmosphere, hydrosphere and habitability on Earth during and following this epoch, but direct traces of this bombardment have been eradicated on our planet by plate tectonics. Indirect evidence about the course of bombardment during this epoch on Earth must therefore come from the lunar record, especially from additional data on the terminal phase of the LHB. For this purpose, documented samples are required for measuring precise radiometric ages of the Orientale Basin and the Nectaris and/or Fecunditatis Basins in order to compare these ages with the time of the earliest traces of life on Earth. A crater count chronology is presently being built up for planet Mars and its surface features. The chronology is based on the established lunar chronology whereby differences between the impact rates for Moon and Mars are derived from local fluxes and impact energies of projectiles. Direct calibration of the Martian chronology will have to come from radiometric ages and cosmic-ray exposure

  9. 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

  10. 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.

  11. Chronological study archaeological sites from Caninde do Sao Francisco, Sergipe state, Brazil, by thermo thermoluminescence technique

    International Nuclear Information System (INIS)

    The ceramic vestiges rescued in the archaeological excavations have been considered important sources of chronological information because they constitute direct fossil of certain cultural periods. The Thermoluminescence Method for dating of inorganic materials has made the determination of ancient ceramics ages possible with adequate precision and accuracy. The intensity of the thermoluminescence emission is proportional to the energy deposited in the crystals, present in the pottery, by means of natural radioisotope material irradiation (U, Th, K and Rb) and cosmic rays. With the objective of determining the chronological profile of archaeological sites from 'Xingo', situated in the Caninde do Sao Francisco city, Sergipe State, Brazilian Northeast, the ages of 4 pottery samples from Justino, Sao Jose, Saco da Onca and Curituba sites were determined in this work. The ceramic collection has great expression because many ceramics are associated to mortuary rites. The acquisition of the site chronology studied in this work is a contribution to studies of ancient communities that lived in the region. The additive dose method was used to determine of the paleodose in the samples, and the TL response of 320 deg C peak as function of the added dose was linear. The annual dose rate was determined by means of the instrumental neutron activation analysis, using the U, Th, K and RB concentration from soil and own sample, which yielded an average annual dose rate of 2.89 ± 0.33 mGy.yr-1. Using of the paleodose and annual dose rate, the ages were determined which remained between 457 - 3716 BP, value which matches with the results obtained by carbon - 14 method in the sample from burned charcoal in Justino site. (author)

  12. 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

  13. Impacts of storm chronology on the morphological changes of the Formby beach and dune system, UK

    Science.gov (United States)

    Dissanayake, P.; Brown, J.; Karunarathna, H.

    2015-07-01

    Impacts of storm chronology within a storm cluster on beach/dune erosion are investigated by applying the state-of-the-art numerical model XBeach to the Sefton coast, northwest England. Six temporal storm clusters of different storm chronologies were formulated using three storms observed during the 2013/2014 winter. The storm power values of these three events nearly halve from the first to second event and from the second to third event. Cross-shore profile evolution was simulated in response to the tide, surge and wave forcing during these storms. The model was first calibrated against the available post-storm survey profiles. Cumulative impacts of beach/dune erosion during each storm cluster were simulated by using the post-storm profile of an event as the pre-storm profile for each subsequent event. For the largest event the water levels caused noticeable retreat of the dune toe due to the high water elevation. For the other events the greatest evolution occurs over the bar formations (erosion) and within the corresponding troughs (deposition) of the upper-beach profile. The sequence of events impacting the size of this ridge-runnel feature is important as it consequently changes the resilience of the system to the most extreme event that causes dune retreat. The highest erosion during each single storm event was always observed when that storm initialised the storm cluster. The most severe storm always resulted in the most erosion during each cluster, no matter when it occurred within the chronology, although the erosion volume due to this storm was reduced when it was not the primary event. The greatest cumulative cluster erosion occurred with increasing storm severity; however, the variability in cumulative cluster impact over a beach/dune cross section due to storm chronology is minimal. Initial storm impact can act to enhance or reduce the system resilience to subsequent impact, but overall the cumulative impact is controlled by the magnitude and number

  14. Impacts of storm chronology on the morphological changes of the Formby beach and dune system, UK

    Directory of Open Access Journals (Sweden)

    P. Dissanayake

    2015-04-01

    Full Text Available Impacts of storm chronology within a storm cluster on beach/dune erosion are investigated by applying the state-of-the-art numerical model XBeach to the Sefton coast, northwest England. Six temporal storm clusters of different storm chronologies were formulated using three storms observed during the 2013/14 winter. The storm power values of these three events nearly halve from the first to second event and from the second to third event. Cross-shore profile evolution was simulated in response to the tide, surge and wave forcing during these storms. The model was first calibrated against the available post-storm survey profiles. Cumulative impacts of beach/dune erosion during each storm cluster were simulated by using the post-storm profile of an event as the pre-storm profile for each subsequent event. For the largest event the water levels caused noticeable retreat of the dune toe due to the high water elevation. For the other events the greatest evolution occurs over the bar formations (erosion and within the corresponding troughs (deposition of the upper beach profile. The sequence of events impacting the size of this ridge-runnel feature is important as it consequently changes the resilience of the system to the most extreme event that causes dune retreat. The highest erosion during each single storm event was always observed when that storm initialised the storm cluster. The most severe storm always resulted in the most erosion during each cluster, no matter when it occurred within the chronology, although the erosion volume due to this storm was reduced when it was not the primary event. The greatest cumulative cluster erosion occurred with increasing storm severity; however, the variability in cumulative cluster impact over a beach/dune cross-section due to storm chronology is minimal. Initial storm impact can act to enhance or reduce the system resilience to subsequent impact, but overall the cumulative impact is controlled by the

  15. 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

  16. 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.

  17. Relationship between dental age, skeletal maturity and chronological age in young orthodontic patients.

    OpenAIRE

    Lund, Erlend; Tonje, Tømmervold

    2014-01-01

    Abstract Objectives: The aim of this study was to find out in what extend the dental age and skeletal maturity relate with the chronological age, in a sample of 50 subjects in the range 7 – 16 years old, from the Northern part of Norway Subjects and methods: The subjects were all patients who had received/were undergoing orthodontic treatment at the Public Dental Service Competence Centre of Northern Norway (TkNN). The sample consisted of 25 males and 25 females, from 7-16 years in ag...

  18. 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...

  19. 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 ...

  20. 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...

  1. 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.

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

    International Nuclear Information System (INIS)

    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)

  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. 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.

  5. 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.

  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. 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.

  8. Chronological Changes of the Signal Intensities of White Matter on the FLAIR Images of Infants

    International Nuclear Information System (INIS)

    To assess the pattern of chronological change for the signal intensities of white matter on the FLAIR images of infants. FLAIR, T1- and T2-weighted images of 119 infants (newborn to 24 months age) were obtained by using a 1.5 T MRI machine. From these images, the signal intensities of 9 different white matter regions were compared to those of the adjacent gray matter and the signal intensities of each image were scored from 1 to 5. The FLAIR images show high signal intensity for the cerebellar peduncle and posterior limb of the internal capsule at birth, but changed to low signal intensities in 2 to 3 months. The low signal intensities of the occipital-, parietal-, and frontal deep white matter and subcortical white matter changed to high signal intensities in 2 months, and they returned to low signal intensities in 10, 11, 12 and 19 months, respectively. The signal intensity of the white matter of infants showed peculiar chronologic changes on the FLAIR images. This knowledge could be helpful for the differentiation of normal white matter development and the lesions that mimic white matter disease in infants

  9. 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 yield grade while breed group had an (P grade. In general, British and British cross bullocks produced 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 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. PMID:22055275

  10. 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.

  11. 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.

  12. The chronology of mangrove swamps of Hadi, Maharashtra, using luminescence dating techniques

    International Nuclear Information System (INIS)

    Mangrove, the plant life associated with the near shore marine habitat, lies in a transitional zone between the marine and terrestrial environments of the low-lying tropical coastlines. The hydrology of this coastal ecosystem is balanced by the tidal amplitude and fresh water input. Study of the temporal changes within the environmental settings of mangroves and its chronology forms an important aspect of any coastal geological programmes. As such, this information could be useful in initiating corrective measures in maintaining the mangroves. Keeping this view in mind, a chronological control for the mangrove profile of Hadi, Malwan, Maharashtra was obtained using Blue Light Stimulated Luminescence (BLSL) to ascertain the paleological reconstruction in the region. Due to the heavy precipitation rates in the region, the samples collected at various depths up to 100 cm were observed to have high moisture contents. Taking this in to account for evaluation of annual dose rate, four samples were dated using BLSL techniques. The ages of the samples were found to be between 1.58 - 5.45 ka. The description of mangroves, their ecological importance, method of dating and the implication thereof are discussed in the paper. (author)

  13. 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

  14. 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

  15. 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...

  16. Revision of Ernst Antevs' New England Varve Chronology: A Record of Meltwater Production and Southeastern LIS Recession: 18.2-12.5 kyr BP (Invited)

    Science.gov (United States)

    Ridge, J. C.

    2013-12-01

    New varve cores and 54 radiocarbon ages, have allowed the correction, closure of a gap, calibration, and expansion of Ernst Antevs' (1922) New England Varve Chronology from sediments of glacial Lake Hitchcock and it's successors in the Connecticut Valley of western New England (northeastern U.S.A.). The continuous 5659-yr chronology (18.2-12.5 kyr BP) has been renumbered as the North American Varve Chronology. Glacial varve thickness (18.2-13.7 kyr BP) documents abrupt changes in meltwater production related to varying ablation rate (summer climate) that is linked to ice sheet recession rates and advances, i.e. cold intervals are times of thin varves and slower ice recession or glacial readvances. To take advantage of the varve-climate relationship it is necessary to identify non-climatic events that can cause varve thickness to change. This includes sudden changes in lake level and flood events triggered by the abrupt drainage of tributary glacial lakes. A chronology of ice recession for intervals terminated by four stillstands and readvances of 1-2 century durations have been determined for the Connecticut Valley (from S to N): 50-100 m/yr in northern Connecticut to southern Massachusetts; Chicopee Readvance; 30-40 m/yr in central Mass.; Hatfield event; 80-90 m/yr from northern Mass. to central New Hampshire; North Charlestown end moraines; 300 m/yr to northern N.H.; Littleton Readvance; >300 m/yr to Quebec. Meltwater produced by ice recession of 300 m/yr modeled as a receding 1-bar ice sheet profile (from 100 km up ice near ELA to margin, valley width of 80 km, glacier flow rate of 200 m/yr at ELA) would be a minimum glacial meltwater discharge in the Connecticut Valley of ~90 x 109 m3/yr. This is ~10X the modern Conn. River discharge at Walpole, NH compressed almost entirely to the melt season. Non-glacial varves deposited after ice receded from the basin (13.7-12.5 kyr BP) also document climate change as a result of varve thickness varying with changes in

  17. Time functions as utilities

    CERN Document Server

    Minguzzi, E

    2009-01-01

    Every time function on spacetime gives a (continuous) total preordering of the spacetime events which respects the notion of causal precedence. The problem of the existence of a (semi-)time function on spacetime and the problem of recovering the causal structure starting from the set of time functions are studied. It is pointed out that these problems have an analog in the field of microeconomics known as utility theory. In a chronological spacetime the semi-time functions correspond to the utilities for the chronological relation, while in a K-causal (stably causal) spacetime the time functions correspond to the utilities for the K^+ relation (Seifert's relation). By exploiting this analogy, we are able to import some mathematical results, most notably Peleg's and Levin's theorems, to the spacetime framework. As a consequence, we prove that a K-causal (i.e. stably causal) spacetime admits a time function and that the time or temporal functions can be used to recover the K^+ (or Seifert) relation which indeed...

  18. 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)

  19. State conservation and chronological contextualization of the Bone Collection 'Gustavo Le Paige'

    International Nuclear Information System (INIS)

    Between the 1950s and 1970s Father Gustavo Le Paige excavated one of the largest osteological collections of Latin America, attracting the attention of numerous researchers over the past 40 years. In his field notes, Le Paige recorded the excavation of 5482 skulls and human bodies deposited in the Instituto de Investigaciones Arqueologicas y Museo of the Universidad Catolica del Norte (San Pedro de Atacama). However, cumulative processes of abandonment and the lack of preventive conservation resulted in the loss of context and a decrease in the quality of preservation of a significant portion of this skeletal collection. Here, we present the current state of preservation of this collection, and 50 new radiocarbon dates that helps the chronological contextualization of 21 of the larger and more representative cemeteries in the Le Paige collection

  20. 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.

  1. 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

  2. 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

  3. 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.

  4. 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...

  5. 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.

  6. 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.

  7. 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 

  8. 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.

  9. 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.

  10. Primary Dental Care 1994-2004: the first ten years. A chronology.

    Science.gov (United States)

    Renson, Ted

    2004-10-01

    The prime purpose of a professional journal is to keep its readers informed of changes of importance affecting the practise of that profession. That is the criterion that I have applied in producing this chronology of the papers that have been published in Primary DENTAL CARE during the past decade. The ambition which has guided me since I received the invitation to carry out this review is a simple one: to include as much as may generally be found useful by general dental practitioners (GDPs), who form the bulk of our readership. In 1789 the English philosopher Jeremy Bentham extolled the virtues of utility for mankind when he declared that 'the greatest happiness of the greatest number is the foundation of morals and legislation'. The contributors that I have included, by contrast, think of their utilitarianism as striving after the most practical. The principal purpose of this chronology is to achieve a summary, without weighing causes or consequences. From past experience, an outstanding virtue of such an aggregated record is that it can inspire fresh patterns of thought and thus encourage the submission of manuscripts as a result of those thoughts. I can think of scarcely any facet of the general practice of dentistry that has not been touched upon, for the most part authoritatively. I hope that these brief aide-memoires may persuade old readers to return to those articles of particular interest to them and that new readers will feel informed about past papers. Every issue of the journal to date has been reviewed. Dates, volume and issue numbers and principal authors' names are all included. With these identifying features any paper, to which reference is made, may be quickly found. It would be manifestly absurd to use precious space on a formal listing of more than 250 references and this listing has, therefore, been omitted. PMID:15509435

  11. 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

  12. 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)

  13. 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.

  14. 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.

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

    Directory of Open Access Journals (Sweden)

    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

  16. 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

  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. 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.

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

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    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.

  20. 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

  1. 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…

  2. 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

  3. 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.

  4. 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.…

  5. Temperature signal instability of tree-ring δ13C chronology in the northeastern Qinghai-Tibetan Plateau

    Science.gov (United States)

    Wang, Wenzhi; Liu, Xiaohong; Xu, Guobao; Zeng, Xiaomin; Wu, Guoju; Zhang, Xuanwen; Qin, Dahe

    2016-04-01

    Tree ring δ13C as a climate proxy is widely used for palaeoclimate research, however, its temporal stability response to the climate change remains unclear under more than one limited factors on tree growth. Here, we used a millennium tree-ring δ13C chronology combining two annual-resolution δ13C chronologies since 1800 from long-lived Qilian juniper (Sabina przewalskii) to assess its instability of the climate signal in the northeastern Qinghai-Tibetan Plateau. Tree-ring δ13C chronologies were strongly correlated with the regional mean April to August temperature from 1956 to 2008, but the associations were absent within the period 1901 to 1955 values in the CRU TS dataset. Comparison of the millennium-long δ13C series with reconstructed Asian temperatures also demonstrated that the δ13C chronology exhibited climate signal temporal instability. Substantial oscillations were revealed using a frequency-dependent analysis and 51-year running correlation analysis from the millennium-long tree-ring δ13C and δ18O series. Dual-isotope approach indicated that stomatal limitations created a statistical significant positive correlation between tree-ring δ13C and δ18O, but photosynthetic rate may be dominant when the correlations were not significant. Our results suggest that tree-ring δ13C series in the northeastern Qinghai-Tibetan Plateau is responded instability to temperature variations in the past 1000 years.

  6. 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

  7. 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

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

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    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.

  9. 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

    -derived material from the Orange River delta) the weight of evidence points towards the dominance of an Orange River source, with localised contribution from fluvially-derived escarpment material close to river courses. Despite the fact that it remains difficult to definitively distinguish between recent Orange River sediment and recycled TSS, because of a great mineralogical similarity, an Orange River source contemporaneous with the accumulation of the sand sea appears to be favoured. Models of landscape development rely on an understanding of the source region, and an Orange River source suggests growth and extension from south to north (a wind-displaced Orange Delta), rather than localised reworking of sediment from the TSS. One proposed model, developed for the southern part of the sand sea, divides accumulation into two distinct phases with different palaeoenvironmental conditions: large draas accumulating under enhanced Pleistocene trade winds and superimposed features on the eastern dune flanks formed by westerly winds moving material over the crest. However, the latter phase could equally be explained by a northerly migration of the superimposed features, and there is still too little in the way of chronological control to construct a coherent picture of dune accumulation and migration for the sand sea as a whole. There are also interesting insights from conceptualising dune bedform patterning in sand seas as a time-dependent, self-organising, complex system, rather than necessarily requiring changing palaeoenvironmental conditions for different scales of features, with some of this research referring directly to the Namib Sand Sea. Refining the details of the accumulation of the Namib Sand Sea requires both detailed site-specific studies and joined-up analysis.

  10. 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

  11. 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

  12. 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

  13. Chronologically overlapping occurrences of nicotine-induced anxiety- and depression-related behavioral symptoms: effects of anxiolytic and cannabinoid drugs

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    Hayase Tamaki

    2007-09-01

    Full Text Available Abstract Background Anxiety and depression are among the most frequently-observed psychiatric symptoms associated with nicotine (NC. In addition to the similarity to other addictive drugs, these NC-induced symptoms are characteristic in that the opposite behavioral effects, i.e. anxiolytic and antidepressant effects, which may reinforce the habitual use of NC, have also been reported. In the present study, the time course of anxiety- and depression-related behavioral alterations was examined in mice. Furthermore, based on the reported similarity in the mechanisms responsible for NC-induced anxiety- and depression-related symptoms, as well as the contribution of brain cannabinoid (CB receptors to these behavioral symptoms, the effects of anxiolytics and CB receptor ligands (CBs against these behavioral symptoms were investigated. Results Repeated subcutaneous NC treatments (0.3 mg/kg, 4 days, compared with a single treatment (0.5 mg/kg, caused both prolonged anxiogenic effects in the elevated plus-maze test, and prolonged depressive effects in the forced swimming test, even at 120 min time point after the last NC treatment. A transient anxiolytic preference for open arms was also observed in the elevated plus-maze test. Among the anxiolytics and CBs, the serotonin 1A (5-HT1A antagonist WAY 100135 and the endogenous mixed CB agonist/antagonist virodhamine (VD, when administered intraperitoneally before each NC treatment, provided the strongest antagonistic effects against the anxiety-related symptoms. However, against the depression-related symptoms, only VD provided significant antagonistic effects in both single and repeated treatment groups. Conclusion The present results support the presence of a chronological overlap of NC-induced anxiety- and depression-related behavioral symptoms, and the contribution of brain CB receptors to these behavioral symptoms. The repeated NC-induced prolongation of these behavioral symptoms and the early transient

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

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    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.

  15. 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.

  16. Differences between chronological and brain age are related to education and self-reported physical activity.

    Science.gov (United States)

    Steffener, Jason; Habeck, Christian; O'Shea, Deirdre; Razlighi, Qolamreza; Bherer, Louis; Stern, Yaakov

    2016-04-01

    This study investigated the relationship between education and physical activity and the difference between a physiological prediction of age and chronological age (CA). Cortical and subcortical gray matter regional volumes were calculated from 331 healthy adults (range: 19-79 years). Multivariate analyses identified a covariance pattern of brain volumes best predicting CA (R(2) = 47%). Individual expression of this brain pattern served as a physiologic measure of brain age (BA). The difference between CA and BA was predicted by education and self-report measures of physical activity. Education and the daily number of flights of stairs climbed (FOSC) were the only 2 significant predictors of decreased BA. Effect sizes demonstrated that BA decreased by 0.95 years for each year of education and by 0.58 years for 1 additional FOSC daily. Effects of education and FOSC on regional brain volume were largely driven by temporal and subcortical volumes. These results demonstrate that higher levels of education and daily FOSC are related to larger brain volume than predicted by CA which supports the utility of regional gray matter volume as a biomarker of healthy brain aging. PMID:26973113

  17. 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

  18. 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...

  19. 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

  20. 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.

  1. 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

  2. Late Otiran sedimentation and glacial chronology in the Warwick valley, southeast Nelson

    International Nuclear Information System (INIS)

    Approximately 14 m of sediment are exposed in a road cutting beneath a landslide deposit in the Warwick valley, southeast Nelson, New Zealand. Three radiocarbon dates and 5 pollen spectra were obtained from organic horizons in these sediments. The dates indicate that lacustrine sedimentation predominated from before 17 500 until 14 450 years ago. This was interrupted by a brief period of gravel aggradation between 17 500 and 16 650 years ago, which is attributed to a glacial advance. Vegetation at the site was consistently dominated by Cyperaceae, with some Gramineae, suggesting a bleak, treeless landscape. Correlation of this information with other radiocarbon dated sites indicates the need for some revision of the chronology of the late Otira Glaciation. A late phase of the Kumara 22 advance occurred between 17 000 and 16 000 years ago, and the Kumara 31 advance did not occur until after about 15 000 years ago. The end of the Otira Glaciation probably occurred between 13 000 and 12 500 years ago. (auth)

  3. 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.

  4. 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.

  5. Time since birth and time left to live: opposing forces in constructing psychological wellbeing

    OpenAIRE

    Demiray, Burcu; Bluck, Susan

    2014-01-01

    Ageing, by definition, involves moving across lived time. Grounded in developmental psychology, particularly lifespan developmental theory, this study examines two time- related factors that may affect psychological wellbeing in adulthood. Particularly, chronological age and perceived time left to live (i.e. future time perspective) are predicted to act as opposing forces in the construction of psychological wellbeing. Young (N=285, 19-29 years) and middle-aged adults (N=135, 14-64 years) sel...

  6. Age, Time, and Decision Making: From Processing Speed to Global Time Horizons

    OpenAIRE

    Corinna E. Löckenhoff

    2011-01-01

    Time and time perceptions are integral to decision making because any meaningful choice is embedded in a temporal context and requires the evaluation of future preferences and outcomes. The present review examines the influence of chronological age on time perceptions and horizons and discusses implications for decision making across the life span. Time influences and interacts with decision making in multiple ways. Specifically, this review examines the following topic areas: (1) processing ...

  7. 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...

  8. Concerning the chronology of Cimabue's oeuvre and the origin of pictorial depth in Italian painting of the later middle ages

    Directory of Open Access Journals (Sweden)

    Polzer Joseph

    2002-01-01

    Full Text Available A study devoted to the gradual emergence of pictorial depth in Cimabue's paintings, and how it applies, together with other factors, to the understanding of their sequential chronology. The conclusions reached underscore the vast difference in Cimabue 's conservative art and the exceptional naturalism of the evolving Life of Saint Francis mural cycle lining the lower nave walls in the upper church of San Francesco at Assisi.

  9. 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...

  10. The accuracy of estimating chronological age from Demirjian and Nolla methods in a Portuguese and Spanish sample

    OpenAIRE

    Tomás, Luís F; Mónico, Lisete SM; Tomás, Inmaculada; Varela-Patiño, Purificación; Martin-Biedma, Benjamín

    2014-01-01

    Background Age determination has great importance in many clinical decisions, being commonly used in odontopediatrics, orthodontics, pediatrics, and forensic medicine. The Nolla and Demirjian et al. methods have been used for these purposes. However, estimating chronological age by means of the dental mineralization stage is not a straightforward analysis, and it is fundamental to test the validity of these methods and their applicability to populations. In this article we intend to compare t...

  11. Key factors in paediatric organ and tissue donation: an overview of literature in a chronological working model

    OpenAIRE

    Siebelink, Marion J.; Albers, Marcel J. I. J.; Roodbol, Petrie F.; van de Wiel, Harry B. M.

    2012-01-01

    There is a growing shortage of size-matched organs and tissues for children. Although examples of substandard care are reported in the literature, there is no overview of the paediatric donation process. The aim of the study is to gain insight into the chain of events, practices and procedures in paediatric donation. Method; a survey of the 19902010 literature on paediatric organ and tissue donation and categorization into a coherent chronological working model of key events and procedures. S...

  12. 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.

  13. Comparative evaluation of dental age, bone age, and chronological age in the human immunodeficiency virus positive children

    OpenAIRE

    Vinod Kumar; Kavitha Patil; Munoli, Karishma B

    2014-01-01

    Background and Objective: The knowledge of bone age and dental age is of great importance for pediatrician and pediatric dentist. It is essential for pediatric dentist to formulate treatment plan and it is a source of complementary information for pediatrician. There are few studies in literature, which showed the relationship between dental age, bone age and chronological age in HIV-positive children. Therefore, objective of this study was to determine and compare dental age, bone age and ch...

  14. 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...

  15. Caloric restriction or catalase inactivation extends yeast chronological lifespan by inducing H2O2 and superoxide dismutase activity

    OpenAIRE

    Mesquita, Ana; Weinberger, Martin; Silva, Alexandra; Sampaio-Marques, Belém; Almeida, Bruno; Leão, Cecília; Costa, Vítor; Rodrigues, Fernando; Burhans, William C.; Ludovico, Paula

    2010-01-01

    The free radical theory of aging posits oxidative damage to macromolecules as a primary determinant of lifespan. Recent studies challenge this theory by demonstrating that in some cases, longevity is enhanced by inactivation of oxidative stress defenses or is correlated with increased, rather than decreased reactive oxygen species and oxidative damage. Here we show that, in Saccharomyces cerevisiae, caloric restriction or inactivation of catalases extends chronological lifespan by inducing el...

  16. Caloric restriction or catalase inactivation extends yeast chronological lifespan by inducing H₂O₂ and superoxide dismutase activity

    OpenAIRE

    Mesquita, Ana Maria Macedo; Weinberger, Martin; Silva, Alexandra; Marques, Belém Sampaio; Almeida, Bruno; Leão, Cecília; Costa, Vitor; Rodrigues, Fernando José dos Santos; Burhans, William C.; Ludovico, Paula

    2010-01-01

    The free radical theory of aging posits oxidative damage to macromolecules as a primary determinant of lifespan. Recent studies challenge this theory by demonstrating that in some cases, longevity is enhanced by inactivation of oxidative stress defenses or is correlated with increased, rather than decreased reactive oxygen species and oxidative damage. Here we show that, in Saccharomyces cerevisiae, caloric restriction or inactivation of catalases extends chronological lifespan by inducing el...

  17. 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...

  18. A Chronological List of References on Switched Capacitor Networks and Techniques for the Period 1981-1992

    OpenAIRE

    A.K. Singh

    1994-01-01

    A chronological list of 440 references on switched capacitor (SC) networks from 1939 to May 1981 was published in this Journal by J. Vandewalle. In this communication, we present a compilation of 1357 references covering the period from May 1981-1992 (along with a supplementary list of 43 missing references for the period before May 1981). The present compilation and the earlier one by Vandewalle put together, thus, constitute an exhaustive bibliography of 1797 references on SC-networks and t...

  19. 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.

  20. Chronological change of electrical resistance in GeCu2Te3 amorphous film induced by surface oxidation

    International Nuclear Information System (INIS)

    Unusual chronological electrical resistance change behavior was investigated for amorphous GeCu2Te3 phase change material. More than a 1 order decrease of electrical resistance was observed in the air even at room temperature. The resistance of the amorphous film gradually increased with increasing temperature and then showed a drop upon crystallization. Such unusual behavior was attributed to the oxidation of the amorphous GeCu2Te3 film. From the compositional depth profile measurement, the GeCu2Te3 film without any capping layer was oxidized in air at room temperature and the formed oxide was mainly composed of germanium oxide. Consequently, a highly-conductive Cu-rich layer was formed in the vicinity of the surface of the film, which reduced the total resistance of the film. The present results could provide insight into the chronological change of electrical resistance in amorphous chalcogenide materials, indicating that not only relaxation of the amorphous, but also a large atomic diffusion contributes to the chronological resistance change. (paper)

  1. Dental maturity as an indicator of chronological age: radiographic assessment of dental age in a brazilian population

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    Lucio Mitsuo Kurita

    2007-04-01

    Full Text Available OBJECTIVE: The purpose of this investigation was to evaluate the applicability of the methods proposed by Nolla and by Nicodemo and colleagues for assessing dental age and its correlation to chronological age. METHODS: Panoramic radiographs of 360 patients from the city of Fortaleza (CE, Brazil aged 7-15 years were used to assess the associations between dental and chronological age. Data were submitted to statistical analysis using the BioEstat 2.0 (2000 software. Student-Neuman-Keuls test was performed and Pearson's correlation coefficients were calculated at 5% significance level. RESULTS: When the Nolla method was applied, the mean difference between true and estimated age for males and females was underestimated. The use of the method proposed by Nicodemo and colleagues also resulted in underestimation, although it was more evident in male subjects. The correlation coefficients between chronological age and estimated dental age were high, with mean values ranging between 0.87 and 0.91 for males and between 0.84 and 0.93 for females. CONCLUSION: Although both methods proved to be reliable in estimating age, the use of correction factors is recommended.

  2. 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.

  3. Use of atomic force microscopy in the forensic application of chronological order of toners and stamping inks in questioned documents.

    Science.gov (United States)

    Kang, Tae-Yi; Lee, Joong; Park, Byung-Wook

    2016-04-01

    This paper describes the application of the atomic force microscopy (AFM) as a nano-indentation method and introduces a new method of identifying the chronological order of the application of the toner and stamping ink on the surface of documents by removing either of them. Various toners were used as samples for the AFM nano-indentation method. The chronological order of the application of the toner and stamping ink with either the toner placed over the stamping ink or the stamping ink placed over the toner, could be identified, regardless of the kinds of toners made by various companies. This paper provides the new approach for physically removing the toner and checking the material below it to identify questioned documents, which allows the method to be used to appraise documents forensically. Blind testing has shown that the method to analyze the chronological order of toner-printed documents and the seal stamping on them could accurately identify the order in all samples, while minimizing damage to the samples. PMID:26874052

  4. 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.

  5. 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

  6. 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

  7. “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.

  8. Fission track dating: methodology and thermo-chronological applications in alpine and continental margin contexts

    International Nuclear Information System (INIS)

    The fission track dating method has proved to be unique in thermo-chronology by its capability to describe the final phases of the cooling history and denudation of metamorphic massifs, like the thermal history of sedimentary formations or the dating of some volcanic materials. In this work we describe this method and present a series of new analytic techniques and calibrations which we realised in the aim of further use in geology. We discuss a few examples of such applications. In the french Occidental Alps, the analysis of fission track on apatite samples from the granites of the Sept Laux (Belledonne massif), in the Eau d' Olle valley, suggests that this method could bring a contribution to the actual discussion about the origin of some alpine valleys. The fission track method suggests that the opening of this valley could be the consequence of an active faulting from the middle Miocene until the present. The characterization of fluvial deposits through their detrital apatites fission tracks record could eventually be used to study river captures related to changes tectonic regimes. Therefore we studied the apatites of a paleo-delta located in the Isere middle valley at the sub-alpine 'sillon' level, and of two valleys, those of the Arc and of the Breda, located up the delta. The distribution of the fission track ages of those mineraIs has not confirmed a previously suggested model, which proposed that the studied paleo-delta could be associated with a paleo-Arc rather than a paleo-Breda. In the Moroccan Occidental Meseta, three granitic massifs located in the Rehamna have been selected for a thermo-chronological study. The analysis of the fission track in zircons and apatites of these granites recorded the thermo-tectonic events which have affected the Meseta ever since the opening of the Central Atlantic Ocean some 200 Ma ago. We show how a numerical simulation model recently (1994) proposed for the analysis of fission track in apatites allows us to specify

  9. Investigation of decadal-scale divergence in tree-ring density chronologies

    Science.gov (United States)

    Vaccaro, A.; Emile-Geay, J.; Anchukaitis, K. J.; Wang, J.

    2013-12-01

    Tree-ring data from certain forest sites at northern circumpolar latitudes and from some at higher elevation show an anomalous decrease in temperature-sensitivity of tree growth starting in the mid-20th century. This phenomenon, known as the ';divergence problem' (DP), leads to tree-ring reconstructions that underestimate the warming trend exhibited by instrumental measurements over recent decades (e.g. D'Arrigo et al. 2008). In a study conducted in 1998, Briffa et al. discovered a type of divergence wherein latewood density (MXD) chronologies from an early manifestation of the Schweingruber tree-ring dataset showed strong interannual correlation to summer temperature measurements, but increasing divergence between the decadal-scale trends of the tree-rings and temperature records during the second half of the 20th century. This low-frequency divergence suggests that although tree-rings may accurately trace year-to-year changes in temperature, they might not capture longer-term warming trends, making them unsuitable for reconstructions of long-term climate variations. There is reason to believe, however, that the divergence found by Briffa (1998) is at least partly due to detrending or related statistical issues (Esper et al. 2009). Herein, we will investigate the distribution of this decadal-scale ';Briffa-style' divergence to see if it is confined to the earlier chronologies in the Schweingruber dataset or if it is persistent throughout more recent tree-ring data as well. Following the methodology of previous DP investigations (e.g. Briffa et al. 1998), we will draw comparisons between a network of MXD data and instrumental temperature records over an early period (1850-1960) and a recent period (1961-2000) to detect decadal-scale divergence in recent decades. We will apply the Mann et al. 2009 (M09) style of RegEM reconstruction to the M09 dataset, with and without controlling for divergence, and also to a new tree-ring database assembled using strict, objective

  10. Developing a chronology for glacial advances in the Spanish Pyrenees with luminescence dating

    Science.gov (United States)

    Rhodes, Edward; Sancho, Carlos; McDonald, Eric; Garcia-Ruiz, Jose

    2014-05-01

    Over the course of 15 years, a significant number of sediment samples directly from glacial contexts, or from significant fluvial aggradations related to glacial advances, have been dated using OSL in the Spanish Pyrenees. These provide a record of significant glaciation early during the last glacial cycle, with subsequent events decreasing in size; the LGM advance appears surprisingly small. The development and further extension of this chronology is limited by two issues. These are i) the degree of incomplete zeroing of the luminescence signal experienced by sand grains during transport in high energy fluvial systems and in glacial contexts, and ii) the poor luminescence characteristics of quartz in this region. Both of these limitations are common, if not ubiquitous, in glaciated mountain landscapes. The second limitation is caused by the luminescence properties of quartz in bedrock, and of quartz in short-residence geomorphic contexts where grains are derived directly from bedrock before being flushed from these environments. In order to overcome these constraints, several different approaches have been taken, using quartz OSL, and more recently taking advantage of recent developments in the dating of K-feldspar using IRSL (Infra-Red Stimulated Luminescence). Single grains of K-feldspar have been dated from a wide range of different high-energy fluvial contexts around the globe, using a post-IR IRSL dating protocol. Several of these localities have independent age control, providing the opportunity to assess this approach. Future directions for luminescence dating applications in Spain, and other circum-Mediterranean regions will be provided.

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

    International Nuclear Information System (INIS)

    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

  12. 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.

  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. 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.

  15. 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.

  16. 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.

  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. Chronology of Chichen Izta, evidences by thermoluminescence; Cronologia de Chichen Izta, evidencias por termoluminiscencia

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, A.; Schaaf, P. [Laboratorio de Termoluminiscencia, Instituto de Geofisica, UNAM, 04510 Mexico D.F. (Mexico); Gonzalez, P.R. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Chung, H. [Facultad de Filosofia y Letras, UNAM, 04510 Mexico D.F. (Mexico)

    2002-07-01

    The establishment of the chronology of Chichen Itza is argued by its stylistic evocations, architectural and iconographical as well as its history related in the sources, as the Chilam Balam, where is named the arrival of foreign tribes as the Xiu and the Itzaes and its settlement in Chichen Itza as well as the return to its origin place. The material evidence of such transition is reflected in the ceramic change of the Pizarra Puuc to the Pizarra Chichen, however, in 13 stratigraphic wells realized in different points of Chichen Itza, it was not found evidence of the layer of the Pizarra Puuc period. In this work the obtained ages of dating by thermoluminescence (TL) are presented, of four samples of ceramics found in the different wells. When our results are compared with the estimated ages for the different groups of ceramics, it was observed that none of they corresponded to the Pizarra Puuc period. These results strenghten the observations realized during excavations, causing the suggestion of new inferences related to the Chichen Itza boom and its relationship with the Maya Classic Period. The used technique for the TL dating was that of fine grain. The interval of artificial dose, of beta radiation of Strontium 90 was between 2 and 30 Gy. The TL signal was obtained heating the samples at 10 C/s until reaching 500 C in the TL Daybreak reader equipment. In order to know the annual dose rate of concentration of potassium ({sup 40} K) by means of the microanalysis technique in the scanning electron microscope was determined, while the uranium content (2{sup 38} U) and thorium ({sup 232} Th) were determined by means of the neutron activation analysis technique using the TRIGA Mark III nuclear reactor. The contribution of the gamma radiation of the soil as well as the contribution of the cosmic radiation was measured with TL dosemeters of CaSO{sub 4} :Dy + Ptfe once the paleodose was known and the annual dose rate of each sample of its age was estimated. (Author)

  19. 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

  20. 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

  1. Preliminary Radiocarbon Chronology and Paleoecological Analysis of the Small Mammals in Samwel and Potter Creek Caves, Shasta County, California, and its Relation to the End-Pleistocene Extinction

    Science.gov (United States)

    Feranec, R. S.; Blois, J. L.; Hadly, E. A.

    2005-12-01

    Although mostly excavated before 1910, the fossil deposits discovered in Samwel and Potter Creek Caves in northern California have been little studied. The deposits within the caves have yielded both extinct megafauna and archaeological remains implying that the deposits cross the Pleistocene-Holocene transition. Small mammals are abundant within these cave deposits, and many of these smaller mammals are from extant species of California, survivors of the end Pleistocene extinction. Because of the abundant fossils collected in stratigraphic context, our ultimate goal is the use these unique sites to assess community and population response of the extant mammals to the end Pleistocene event. However, our initial aim was to answer the following two questions regarding the small mammal communities: (1) What is the chronology of the small mammals in the cave deposits? (2) Are ecological changes occurring within the small mammal taxa? To determine chronology, we prepared 10 small mammal samples for radiocarbon analysis using standard techniques. The samples were analyzed and dated at the Lawrence Livermore National Laboratory. Our dates, selected from across the strata, ranged from 1,200 to 21,000 radiocarbon years before present. For a preliminary assessment of ecological changes through time, we used cranial metrics of ground squirrels ( Spermophilus sp.). Diastemal length (the distance between the first molariform tooth and incisor) is an index of body size, which is a function of the physiology of the individual. Toothrow measures the length of the molariform teeth, and does not change with the ontogeny of the individual, but can represent heritable, evolutionary changes in size or species replacement. Our preliminary results are promising, demonstrating a significant decrease in diastemal length, or ecophenotypic body size, at the top of the deposit. No significant change was observed in toothrow length. Our results confirm that the deposits of these northern

  2. Dental and Chronological Ages as Determinants of Peak Growth Period and Its Relationship with Dental Calcification Stages

    Science.gov (United States)

    Litsas, George; Lucchese, Alessandra

    2016-01-01

    Purpose: To investigate the relationship between dental, chronological, and cervical vertebral maturation growth in the peak growth period, as well as to study the association between the dental calcification phases and the skeletal maturity stages during the same growth period. Methods: Subjects were selected from orthodontic pre-treatment cohorts consisting of 420 subjects where 255 were identified and enrolled into the study, comprising 145 girls and 110 boys. The lateral cephalometric and panoramic radiographs were examined from the archives of the Department of Orthodontics, Aristotle University of Thessaloniki, Greece. Dental age was assessed according to the method of Demirjian, and skeletal maturation according to the Cervical Vertebral Maturation Method. Statistical elaboration included Spearman Brown formula, descriptive statistics, Pearson’s correlation coefficient and regression analysis, paired samples t-test, and Spearman’s rho correlation coefficient. Results: Chronological and dental age showed a high correlation for both gender(r =0.741 for boys, r = 0.770 for girls, p0.001). The t-test revealed statistically significant differences between these variables (p<0.001) during the peak period. A statistically significant correlation (p<0.001) between tooth calcification and CVM stages was determined. The second molars showed the highest correlation with CVM stages (CVMS) (r= 0.65 for boys, r = 0.72 for girls). Conclusion: Dental age was more advanced than chronological for both boys and girls for all CVMS. During the peak period these differences were more pronounced. Moreover, all correlations between skeletal and dental stages were statistically significant. The second molars showed the highest correlation whereas the canines showed the lowest correlation for both gender. PMID:27335610

  3. Molluscan biozones, event/cycle chronostratigraphy, and sealevel history; a new integrated Cretaceous chronology for Northern South America

    Energy Technology Data Exchange (ETDEWEB)

    Villamil, T.; Johnson, C.C.; Kauffman, E.G. (Univ. of Colorado, Boulder (United States))

    1993-02-01

    The Cretaceous marine basins of northern South America, in their evolution, record a dynamic interplay between regional and plate tectonics, sealevel history, changing paleo-ocean/paleoclimate systems, and the rates/patterns of sedimentation driven by both allocyclic and autocyclic processes. Regional interpretation of these complex interactions; and the evolution of the South American passive margin, requires a high-resolution stratigraphic system of dating and correlation. Because short-term events and dynamic processes shape the stratigraphic record, this chronology must have a resolution of <1 million years, ideally 10's-100's of ka correlation units. This resolution does not currently exist in South America, where Cretaceous radiometric dates and paleomagnetic analyses are few, event/cycle chronostratigraphy and sequence stratigraphy are not yet well developed and where current biostratigraphic resolution based on mollusks averages 1- > 2 Ma/biozone. New efforts to establish a more refined chronology for South America involve: (a) High-resolution (cm-scale) event/cycle chronostratigraphic analyses of key Colombian and Venezuelan sections; (b) search for datable ash/bentonite beds; (c) detailed paleontologic collecting to firmly establish biostratigraphic ranges of mollusks and microplankton with high biostratigraphic potential, and to formulate regional assemblage zones; and (d) integration of these diverse data through graphic correlation to provide a new chronologic standard for the region. Initial results are presented: Middle Cretaceous biozones are now resolved to <500 ka/zone; a fine-scale sequence stratigraphy and sealevel history has been determined; numerous regional physical and chemostratigraphic event beds are identified; and climate-driven cyclostratigraphy has been resolved to at least 50 ka within the passive margin sequences of Colombia and Venezuela.

  4. Mediterranean fluvial response to long-term Quaternary climate change: Improving chronologies by coupling OSL and U-series techniques

    Science.gov (United States)

    Candy, Ian; Pope, Richard

    2010-05-01

    Many studies have attempted to understand the relationship between Late Quaternary climate change and Mediterranean river activity over the last 200,000 years (Macklin et al., 2002). The long-terrace records associated with most large river systems and the thick aggradation of fan sediments associated with smaller catchments in southern Europe and north Africa make the Mediterranean an ideal region to test this relationship. Such studies have been further enhanced by recent improvements in optically stimulated luminescence (OSL) and U-series dating techniques which are widely applicable in this region. Despite the fact that combining these two techniques provides the best potential method for constructing high precision chronologies this has rarely been done. In this paper we discuss the problems and advantages of producing "coupled" chronologies with reference to examples from southern Spain and Crete. In both of these examples the use of U-series and OSL dating has allowed the age of terrace aggradation and terrace abandonment (incision) to be constrained, consequently our understanding of fluvial "response" is greatly improved. The paper concludes by discussing further problems in terms of constructing fluvial chronologies which need to be considered and the problems of understanding the climate history of the region in which the catchment is found. Macklin, M.G., Fuller, I.C., Lewin, J., Maas, G.S., Passmore, D.G., Rose, J., Woodward, J.C., Black, S., Hamlin, R.H.B., Rowan, J.S., 2002. Correlation of fluvial sequences in the Mediterranean basin over the last 200 ka and their relationship to climate change. Quaternary Science Reviews, 21, 1633 - 1641.

  5. 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.

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

    International Nuclear Information System (INIS)

    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.

  7. 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)

  8. 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

  9. The effects of the target material properties and layering on the crater chronology: the case of Raditladi and Rachmaninoff basins on Mercury

    CERN Document Server

    Marchi, S; Cremonese, G; Martellato, E; Giacomini, L; Prockter, L

    2011-01-01

    In this paper we present a crater age determination of several terrains associated with the Raditladi and Rachmaninoff basins. These basins were discovered during the first and third MESSENGER flybys of Mercury, respectively. One of the most interesting features of both basins is their relatively fresh appearance. The young age of both basins is confirmed by our analysis on the basis of age determination via crater chronology. The derived Rachmaninoff and Raditladi basin model ages are about 3.6 Ga and 1.1 Ga, respectively. Moreover, we also constrain the age of the smooth plains within the basins' floors. This analysis shows that Mercury had volcanic activity until recent time, possibly to about 1 Ga or less. We find that some of the crater size-frequency distributions investigated suggest the presence of a layered target. Therefore, within this work we address the importance of considering terrain parameters, as geo-mechanical properties and layering, into the process of age determination. We also comment o...

  10. The Cell Wall Protein Ecm33 of Candida albicans is Involved in Chronological Life Span, Morphogenesis, Cell Wall Regeneration, Stress Tolerance, and Host–Cell Interaction

    Science.gov (United States)

    Gil-Bona, Ana; Reales-Calderon, Jose A.; Parra-Giraldo, Claudia M.; Martinez-Lopez, Raquel; Monteoliva, Lucia; Gil, Concha

    2016-01-01

    Ecm33 is a glycosylphosphatidylinositol-anchored protein in the human pathogen Candida albicans. This protein is known to be involved in fungal cell wall integrity (CWI) and is also critical for normal virulence in the mouse model of hematogenously disseminated candidiasis, but its function remains unknown. In this work, several phenotypic analyses of the C. albicans ecm33/ecm33 mutant (RML2U) were performed. We observed that RML2U displays the inability of protoplast to regenerate the cell wall, activation of the CWI pathway, hypersensitivity to temperature, osmotic and oxidative stresses and a shortened chronological lifespan. During the exponential and stationary culture phases, nuclear and actin staining revealed the possible arrest of the cell cycle in RML2U cells. Interestingly, a “veil growth,” never previously described in C. albicans, was serendipitously observed under static stationary cells. The cells that formed this structure were also observed in cornmeal liquid cultures. These cells are giant, round cells, without DNA, and contain large vacuoles, similar to autophagic cells observed in other fungi. Furthermore, RML2U was phagocytozed more than the wild-type strain by macrophages at earlier time points, but the damage caused to the mouse cells was less than with the wild-type strain. Additionally, the percentage of RML2U apoptotic cells after interaction with macrophages was fewer than in the wild-type strain. PMID:26870022

  11. 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

  12. The Perceived Effect of Time on HIV/AIDS Identity Incorporation

    Science.gov (United States)

    Baumgartner, Lisa M.

    2012-01-01

    Individuals experience disease in a variety of contexts. In this study, I examined how the temporal context (e.g., historical time, social time, chronological age and the passage of time) affected the incorporation of the HIV/AIDS identity into the self. I used semi structured interviews to collect data from 36 individuals living with HIV/AIDS.…

  13. 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.

  14. 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.

  15. 1,100,000 year history of Siberian permafrost based on U-Pb chronology of speleothems

    Science.gov (United States)

    Vaks, Anton; Mason, Andrew J.; Breitenbach, Sebastian F. M.; Kononov, Alexander M.; Osintcev, Alexander V.; Henderson, Gideon M.

    2014-05-01

    We have used U-Pb dating of the speleothems from Siberian Ledyanaya Lenskaya Cave for tracing of permafrost thawing events during the last 1.1 million years. Rain and snowmelt waters can penetrate into caves only when the soil and subsoil temperatures are above 0° C and permafrost above the cave is discontinuous or absent. Therefore, speleothems in regions currently affected by permafrost provide a tracer of past permafrost thawing events. Ledyanaya Lenskaya Cave is located at 60° 22'N-116° 57'E, on the southern boundary of continuous permafrost zone, with no present-day water seepage in the cave. Temperatures in the region range from -32° C (January) to +18° C (July), with mean annual temperature of ~-6° C. U-Th dating of speleothems from this cave in a previous study [1] showed that the youngest speleothem growth period occurred at 427±23 thousand years ago (ka), during the early Marine Isotope Stage (MIS) 11. During this episode global temperature was 1.5° C higher than pre-industrial levels, and ~0.7° C above the present. In the current study two horizons at the base of a stalagmite were dated using U-Pb chronology [2]. Isochron ages of 1074.1 +7.9/-6.9 ka and 951.4 +3.6/-4.4 ka were obtained. Timing of these permafrost thawing events correlates with events of exceptionally high Pacific Warm Pool sea surface temperature (~+30° C)[3]. During these warm episodes the average global temperature was 1.2-1.3° C higher than pre-industrial temperatures. These findings put the threshold of thawing of the continuous permafrost near its southern boundary slightly lower than it was found previously. The dating work is still in process and is now focusing on growth periods older than MIS-11 but younger than 950 ka. The oldest horizon of the stalagmite grew on the bedrock. This layer was probably amongst the first vadose speleothems that formed after the cave was uplifted above the groundwater table (associated with the nearby Lena River). Today the cave is ~50

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. High-resolution chronology for the Mesoamerican urban center of Teotihuacan derived from Bayesian statistics of radiocarbon and archaeological data

    Science.gov (United States)

    Beramendi-Orosco, Laura E.; Gonzalez-Hernandez, Galia; Urrutia-Fucugauchi, Jaime; Manzanilla, Linda R.; Soler-Arechalde, Ana M.; Goguitchaishvili, Avto; Jarboe, Nick

    2009-03-01

    A high-resolution 14C chronology for the Teopancazco archaeological site in the Teotihuacan urban center of Mesoamerica was generated by Bayesian analysis of 33 radiocarbon dates and detailed archaeological information related to occupation stratigraphy, pottery and archaeomagnetic dates. The calibrated intervals obtained using the Bayesian model are up to ca. 70% shorter than those obtained with individual calibrations. For some samples, this is a consequence of plateaus in the part of the calibration curve covered by the sample dates (2500 to 1450 14C yr BP). Effects of outliers are explored by comparing the results from a Bayesian model that incorporates radiocarbon data for two outlier samples with the same model excluding them. The effect of outliers was more significant than expected. Inclusion of radiocarbon dates from two altered contexts, 500 14C yr earlier than those for the first occupational phase, results in ages calculated by the model earlier than the archaeological records. The Bayesian chronology excluding these outliers separates the first two Teopancazco occupational phases and suggests that ending of the Xolalpan phase was around cal AD 550, 100 yr earlier than previously estimated and in accordance with previously reported archaeomagnetic dates from lime plasters for the same site.

  2. 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

  3. 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

  4. 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.

  5. Luminescence dating of flash flood deposits: a new approach for the chronological study of ancient irrigation perimeters in southern Yemen

    International Nuclear Information System (INIS)

    This study is an attempt to assess the age of ancient irrigation silts from Southern Yemen using the optically stimulated luminescence (OSL) of the constituent K-feldspar grains. This OSL dating method is tested on the al-Haraja irrigation sequence (Wadi Bayhan) which overlies an archaeological occupation level previously dated at 2 203±123 years BP by 14C. The OSL age estimates range between 2 097±177 years at the bottom of the sequence and 1 555±150 years at the top. This study demonstrates the potential of the luminescence dating method to provide chronological information on the deposition of ancient silts following irrigation in arid environment where 14C datable material is rare. (authors)

  6. 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

    ) and thermally transferred OSL (TT-OSL) signals. Since both the latter are associated with systematic uncertainties due to the potential (a)-thermal instability of these signals, a search continues for alternative, and demonstrably stable luminescence signals that can cover the entire Quaternary...... timescale. Here we explore the violet stimulated luminescence (VSL) signal at the Luochuan section, which provides a continuous archive of homogenous sediment with favourable luminescence characteristics and a solid independent age framework. By testing several VSL protocols and their associated performance......, we 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...

  7. Chronology and petrogenesis of young achondrites, Shergotty, Zagami, and ALHA77005 - Late magmatism on a geologically active planet

    Science.gov (United States)

    Shih, C.-Y.; Wooden, J. L.; Bansal, B. M.; Wiesmann, H.; Nyquist, L. E.; Bogard, D. D.; Mckay, G. A.

    1982-01-01

    Three achondrites were examined for chronology, petrogenesis, and relationships among the shergotites. Isotopic and trace elements analyses were carried out through neutron activation and mass spectrometry on Shergotty, Zagami, and ALHA77005 samples. Attention was given the Rb-Sr, Sm-Nd, and the Ar-39/Ar-40 ages in the samples. Evidence was detected for a shock metamorphism and a younger age of the meteorites than with most other achondrites. Depletions of the rare-earth elements were observed in Shergotty and Zagami, and to a more pronounced degree in ALHA77005. The Rb-Sr internal isochrons for all three meteorites were about 180 Myr, while the Ar-39/Ar-40 plateau ages of Shergotty and Zagami maskelynite were determined at 250-260 Myr. No precise identification of the crystallization ages was found. It is suggested that the achondrites originated in a parent body which experienced at least two epochs of sustained melting.

  8. 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.

  9. The history of Nuclear Medicine - a chronological presentation of its origins in Natural Sciences, Technology, and Medicine

    International Nuclear Information System (INIS)

    Nuclear medicine represents a young field in medicine, established as an independent discipline not longer than 50 years ago. The origins, however, date back to the beginning of the 20th century. As in hardly any other medical fields, the discoveries in physics, chemistry, technology of measurements, and molecular biology created the preconditions that made it possible to apply radioactive substances for the purpose of human diagnostic and therapy. Some 'milestones' are selected here from a number of significant research achievements. They will be presented in chronological order - thematically grouped in 5 chapters - each complemented by short explanations. In the reference list, the authors applied particular care in citing the first original publications. (orig.)

  10. 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.

  11. Explosive lava-water interactions I: architecture and emplacement chronology of volcanic rootless cone groups in the 1783-1784 Laki lava flow, Iceland

    Science.gov (United States)

    Hamilton, Christopher W.; Thordarson, Thorvaldur; Fagents, Sarah A.

    2010-05-01

    To determine the relationships between rootless cone emplacement mechanisms, morphology, and spatial distribution, we mapped the Hnúta and Hrossatungur groups of the 1783-1784 Laki lava flow in Iceland. We based our facies maps on Differential Global Positioning System (DGPS) measurements, photogeological interpretations, and supporting field observations. The study area covers 2.77 km2 and includes 2216 explosion sites. To establish the timing of rootless cone formation we incorporated tephrochronological constraints from eighty-eight stratigraphic sections and determined that the Hnúta and Hrossatungur groups are composite structures formed by the emplacement of six geographically and chronologically discrete domains. Rootless eruptions initiated in domain 1 on the first day of the Laki eruption (June 8, 1783) and lasted 1-2 days. The second episode of rootless activity began in domain 2 on June 11 and lasted 1-3 days. The four domains of the Hrossatungur group dominantly formed after June 14 and exhibit a complex emplacement sequence that reflects interactions between the Laki lava, contemporaneously emplaced rootless cones, and an existing topographic ridge. In the study area, we identify three distinct rootless cone archetypes (i.e., recurring morphological forms) that are related to tube-, channel-, and broad sheet lobe-fed eruptions. We assert that emplacement of lava above compressible substrates (e.g ., unconsolidated sediments) may trigger rootless eruptions by causing subsidence-induced flexure and failure of the basal crust, thereby allowing molten lava (fuel) to come into direct contact with groundwater (coolant) and initiating analogs to explosive molten fuel-coolant interactions (MFCIs).

  12. [Chronological analyses of neuropathological and molecular biological changes in affected spinal cord of HTLV-I-infected rat (HAM rat disease)].

    Science.gov (United States)

    Ohya, O

    2000-03-01

    The author chronologically analyzed neuropathological aspects of the demyelination process in spinal cords of a rat model of human T-cell leukemia virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) from early asymptomatic to late disease stage for clarifying the pathogenetic roles of HTLV-I in central nervous system. There was no significant difference in histopathological and immunohistochemical findings between the rats within 7 months after the HTLV-I infection and age-matched controls. The first sign of demyelination was the appearance of apoptotic cell death beginning at 7 months after the infection and the apoptotic cell number gradually increased to 12 cells per a whole horizontal section of the spinal cord, in contrast to 5 cells in the control rats. The majority of the apoptotic cells were shown to be oligodendrocytes by immunohistochemical stain with an anti-myelin oligodendrocyte glycoprotein antibody. Increment of activated microglia/macrophages started at 9 months after the infection and they rapidly increased from 15 months to reach 600 cells per a whole horizontal section, in contrast to 300 cells in the control rats. Rapid increase of gemistocytic astrocytes was found from 20 months after the infection (the late disease stage). Molecular analysis of the spinal cords revealed that HTLV-I provirus DNA was evident as early as 4 months after the infection, and massages of HTLV-I pX and tumor necrosis factor (TNF)-alpha began to be expressed at 7 months, just before or at the same time as the appearance of the apoptotic cells. The collective evidence suggests that the apoptotic death of oligodendrocytes, which may be induced either directly by the local expression of HTLV-I or indirectly by upregulated cytotoxic humoral mediators, such as TNF-alpha, through the transactive function of p40 Tax, is the major cause of chronic progressive myelopathy in WKAH rats with HTLV-I infection. PMID:10791252

  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. PMID:26318182

  14. 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.

  15. 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.

  16. 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

  17. The Fears, Phobias and Anxieties of Children with Autism Spectrum Disorders and Down Syndrome: Comparisons with Developmentally and Chronologically Age Matched Children

    Science.gov (United States)

    Evans, David W.; Canavera, Kristin; Kleinpeter, F. Lee; Maccubbin, Elise; Taga, Ken

    2005-01-01

    This study compared the fears and behavior problems of 25 children with an autism spectrum disorder (ASD), 43 children with Down syndrome (DS), 45 mental age (MA) matched children, and 37 chronologically age (CA) matched children. Children's fears, phobias, anxieties and behavioral problems were assessed using parent reports. Significant…

  18. Index to Nuclear Safety. A technical progress review by chronology, permuted title, and author. Vol. 11, No. 1 through Vol. 15, No. 6

    International Nuclear Information System (INIS)

    This issue of the Index to Nuclear Safety covers only articles included in Nuclear Safety, Vol. 11, No. 1, through Vol. 15, No. 6. This index is presented in three sections as follows: Chronological List of Articles by Volume; Permuted Title (KWIC) Index; and Author Index. (U.S.)

  19. 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

    indications of the onset of Neoglaciation occurring around c. 5,500 a BP is in good agreement with glacier chronology in maritime Scandinavia. In addition, detailed analysis of the glacier variations during the ‘Little Ice Age' and the 20th century AD shows major parallels between both study areas. However, there is little/no evidence of major Early Holocene advances in New Zealand. One hypothesis for this difference is the influence on melt-water outbursts from the disintegrating remnants of the Laurentide Ice Sheet into the North Atlantic sector representing a major but regional factor. The importance of including analysis of recent glacier variations during the 20th and 21st centuries with the interpretation of Holocene glacier chronologies needs to be highlighted in a more pronounced way. In difference to earlier periods, there is sufficient meteorological and glaciological data (as e.g. mass-balance studies) available. Detailed investigation revealed that the most prominent periods of glacier advance and mass gain at the maritime mountain glaciers studied were unambiguously related to increased precipitation and stronger zonal patterns of atmospheric circulation. By contrast, increase summer air temperatures were found responsible for the occurrence of strong frontal retreat during recent years. Rather short periods of less than 10 years caused sufficient length variation during the past few decades, i.e. on a multi-annual to decadal scale. Furthermore, the ‘glaciological regime' empirically describing the relationships between mass-balance or length variation and climate or weather conditions was demonstrated to be variable through time. As this variability is specific for maritime glaciers, one would expect temporal differentiation in addition to the widely accepted spatial differentiation in Holocene glacier chronologies. In contrast to more continental mountain glaciers, reconstructions of Holocene glacier variations cannot be performed entirely depending on

  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.

  1. Sr isotopes in the Orgueil CI meteorite: Chronology of early solar system hydrothermal activity

    Indian Academy of Sciences (India)

    J D Macdougall

    2000-03-01

    New Sr isotopic analyses and calculated formation ages of carbonates from the Orgueil CI meteorite are reported. Among the samples analyzed in this work, dolomites give the youngest formation ages and may have been deposited intermittently starting near the time of parent body formation and continuing for at least 30 Ma. The Sr isotope data also suggest that breunnerites (Fe-Mn-Mg carbonates) crystallized after dolomite formation. Leaching experiments on bulk meteorite samples provide evidence for a very mobile, water soluble Sr reservoir in Orgueil that is characterized by extremely radiogenic Sr (87Sr/86Sr ≈ 0.81- 0.82). This unsupported Sr reflects recent element redistribution, possibly at the time of parent body breakup recorded by the ∼10 Ma exposure age of Orgueil. The carbonate data in particular corroborate earlier indications that hydrothermal processes were among the earliest events to affect the CI parent body.

  2. 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.

  3. 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

  4. Duration of estrogen deprivation, not chronological age, prevents estrogen's ability to enhance hippocampal synaptic physiology

    OpenAIRE

    Smith, Caroline C.; Vedder, Lindsey C.; Nelson, Amy R.; Bredemann, Teruko M.; McMahon, Lori L.

    2010-01-01

    Whether estrogen replacement is beneficial to cognitive health is controversial. Some studies have shown that estrogen replacement therapy (ERT) relieves memory impairment associated with menopause in women, whereas others suggest that estrogen not only is incapable of providing a benefit, but actually can be detrimental. One possible explanation for this discrepancy in study findings could be the varying time after menopause at which ERT is initiated. It has been proposed that a critical per...

  5. Argon 40-argon 39 chronology of lithic clasts from the Kapoeta howardite

    International Nuclear Information System (INIS)

    40Ar-39Ar age spectra has been measured on plagioclase separates from three basaltic clasts (A, B, C), a pyroxene separate from clast B, and a total sample of a fourth basaltic clast (rho) from the Kapoeta achondritic meteorite. The Ar data show that three of the four clasts crystallized >= 4.5 AE ago. Xe measurements indicate all four formed within a 0.1 AE period. Three clasts have suffered various degrees of 40Ar loss since that time. The times of 40Ar degassing do not cluster about a single time analogous to the lunar cataclysm. The survival of >= 4.5 AE ages contrasts with the general absence of ages >= 4.0 AE on the moon. The Ar retention age of clast B of >= 4.57 AE is atypically older than the RB-Sr age of 3.6 AE. The 3.5 AE Ar age of clast A is distinctly younger than the Rb-Sr age of 3.9 AE. The K-Ar and Rb-Sr systems are clearly not equivalent dating techniques in these instances. The combined evidence of Ar, Xe and Rb-Sr studies suggests the period of volcanism on the Kapoeta parent planet was restricted to the first approximately 0.2 AE of solar system history. The subsequent thermal metamorphic histories recorded in each of the four clasts after formation are distinctly different. The clasts must have existed as independent fragments at least as recently as 3.5 AE ago. The cosmic ray exposure ages of all the four clasts are similar (approximately 3 Myr), and are not significantly different from that of the bulk meteorite. The clasts spent essentially all of the time prior to the formation of Kapoeta at depths greater than a few meters. (author)

  6. EVALUATION OF CHRONOLOGICAL ASPECTS OF COLLECTION AND TRANSPORTATION OF MUNICIPAL SOLID WASTE (MSW SYSTEM IN URMIA

    Directory of Open Access Journals (Sweden)

    A. Jalilzadeh, Y. Rahimi and A. Parvaresh

    2005-10-01

    Full Text Available Municipal solid waste (MSW is a serious environmental hazard and social problem in Iran. Currently a high volume of solid waste is generated every day in the district towns of Iran and unfortunately solid waste management is being deteriorated due to the limited resources to handle the increasing rate of generated waste. Due to this fact that more than 60% of solid waste management cost is usually alocated for purpose collection and transportation of generated solid waste in the city. Analysis of this section and understanding of its effect on the management system could have a great role in reduction the costs and solving many of exist problems. This study illustrate the effectiveness of timing managing an MSW economy and that has been carried out as a case study in Urmia. Results of this research illustrsate that 58.3% in Neisan, 68.7% in Khavar, 61.5% in Benz, 81.3% in Compactor and 59.3% in FAUN 0f each cycle time is pickup time.. Mean of traveling speed for Van, Mini-truck, Truck, FAUN and Compactor was 35,46,41,38 and 42 kilometer per hour respectively. Total spent time for collection and transportation of solid waste were 1:21 hour with Van, 1:23 hour with Mini-truck, 1:29 hour with Truck, 17 minutes with FAUN and 57 minutes with Compactor. Result of this study illustrated Van is the most economic vehicle for solid waste collection system in Urmia city. Generally, priority to usage of solid waste collection vehicles illustrate in below: Truck < Mini-truck < Compactor < Van < FAUN

  7. Lichenometry in the Cordillera Blanca, Peru : "Little Ice Age" moraine chronology

    OpenAIRE

    O. Solomina; Jomelli, Vincent; Kaser, G.; Ames, A; Berger, B; Pouyaud, Bernard (dir.)

    2007-01-01

    This paper is a comparison and compilation of lichenometric and geomorphic studies performed by two independent teams in the Cordillera Blanca, Peru, in 1996 and 2002 on 66 "Little Ice Age" moraines of 14 glaciers. Using eleven new control points, we recalibrated the initial rapid growth phase of the previously established Rhizocarpon subgenus Rhizocarpon growth curve. This curve was then used to estimate the age of "Little Ice Age" moraines. The time of deposition of the most prominent and n...

  8. Radium and radium-daughter nuclides in carbonates: a brief overview of strategies for determining chronologies

    International Nuclear Information System (INIS)

    Radium isotopes have been used extensively to trace the movement of groundwater as well as oceanic water masses, but these radionuclides (and their daughters) are also useful chronometers for the determination of the time scales of other Earth and environmental processes. The purpose of this overview is to present the application of Ra and Ra daughters in the dating of carbonates. We show that the choice of dating method (decay of excess radionuclide or ingrowth of daughter) depends strongly on the parent/daughter activity ratios in the water in which the carbonate was precipitated. Thus freshly precipitated carbonates uniformly show excesses of 226Ra relative to its parent 230Th, and 226Ra decay can provide ages of carbonates over Holocene time scales. In contrast, carbonates are precipitated in waters of greatly varying 210Pb/226Ra. Corals, deep-sea hydrothermal vent clams and the shelled cephalopod Nautilus live in waters with significant dissolved 210Pb and all show excesses of 210Pb in their carbonate. Bivalve molluscs from nearshore and coastal waters, and carbonates deposited from groundwater environments (e.g. travertines) in which 210Pb is efficiently scavenged from solution, show deficiencies of 210Pb relative to 226Ra. In contrast, fish otoliths strongly discriminate against 210Pb regardless of the environment in which the fish lives. Deficiencies of 228Th relative to 228Ra are common in all carbonates. Useful time ranges for the 210Pb/226Ra and 228Th/228Ra chronometers are ∼100 y and ∼10 y, respectively.

  9. Radium and radium-daughter nuclides in carbonates: a brief overview of strategies for determining chronologies

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Sabine, E-mail: s.schmidt@epoc.u-bordeaux1.f [CNRS, UMR5805 EPOC, Avenue des Facultes, F-33405 Talence Cedex (France); Universite de Bordeaux, OASU, UMR5805 EPOC, F-33405 Talence Cedex (France); Cochran, J. Kirk [Marine Sciences Research Center, School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York 11794-5000 (United States)

    2010-07-15

    Radium isotopes have been used extensively to trace the movement of groundwater as well as oceanic water masses, but these radionuclides (and their daughters) are also useful chronometers for the determination of the time scales of other Earth and environmental processes. The purpose of this overview is to present the application of Ra and Ra daughters in the dating of carbonates. We show that the choice of dating method (decay of excess radionuclide or ingrowth of daughter) depends strongly on the parent/daughter activity ratios in the water in which the carbonate was precipitated. Thus freshly precipitated carbonates uniformly show excesses of {sup 226}Ra relative to its parent {sup 230}Th, and {sup 226}Ra decay can provide ages of carbonates over Holocene time scales. In contrast, carbonates are precipitated in waters of greatly varying {sup 210}Pb/{sup 226}Ra. Corals, deep-sea hydrothermal vent clams and the shelled cephalopod Nautilus live in waters with significant dissolved {sup 210}Pb and all show excesses of {sup 210}Pb in their carbonate. Bivalve molluscs from nearshore and coastal waters, and carbonates deposited from groundwater environments (e.g. travertines) in which {sup 210}Pb is efficiently scavenged from solution, show deficiencies of {sup 210}Pb relative to {sup 226}Ra. In contrast, fish otoliths strongly discriminate against {sup 210}Pb regardless of the environment in which the fish lives. Deficiencies of {sup 228}Th relative to {sup 228}Ra are common in all carbonates. Useful time ranges for the {sup 210}Pb/{sup 226}Ra and {sup 228}Th/{sup 228}Ra chronometers are {approx}100 y and {approx}10 y, respectively.

  10. Uranium Series Chronology of the Late Pleistocene Basalt from the Longgang Volcanoes, Jilin Province

    Institute of Scientific and Technical Information of China (English)

    YU Fusheng; HAN Song; MA Zhibang; XIE Ruijie

    2005-01-01

    The Longgang volcanic cluster located in Jilin Province belongs to one of the active volcanic regions in northeast China, and has been active in modem times. In view of the multiple eruptions in history, it is very important to determine the age of each eruption for evaluating the volcanic hazards. Two alkaline basalt samples taken from Dayizishan and Diaoshuihu were analyzed with the U-series component dating after magnetic separation. The ages of the two samples are (71±9) ka and (106±13) ka B.P., respectively. These data indicate that there existed intensive eruption activities during the late Pleistocene.

  11. Phengite-based chronology of K- and Ba-rich fluid flow in two paleosubduction zones.

    Science.gov (United States)

    Catlos, E J; Sorensen, S S

    2003-01-01

    Subduction recycles aqueous fluids from slab and sediment to the mantle. Subduction zones are long-lived, but time scales for fluid-rock interaction within subduction complexes are uncertain. Large-ion lithophile elements (potassium and barium) were added to eclogite (subducted basalt) during high pressure/temperature metamorphism via phengite crystallization from subduction zone fluids. Phengite grains from eclogite blocks and their metasomatic selvages yielded 40Ar/39Ar ages across grains and between samples that indicate 25 and 60 million years of fluid-rock interaction in the Samana Complex, Dominican Republic, and the Franciscan Complex, California, respectively. PMID:12511647

  12. Luminescence chronology of cave sediments at the Atapuerca paleoanthropological site, Spain

    OpenAIRE

    Berger, Glenn W.; Pérez-González, Alfredo; Carbonell i Roura, Eudald; Arsuaga, Juan Luis; Ku, Teh-Lung

    2008-01-01

    Ascertaining the timing of the peopling of Europe, after the first out-of-Africa demographic expansion at the end of the Pliocene, is of great interest to paleoanthropologists. One of the earliest direct evidences for fossil hominins in western Europe comes from an infilled karstic cave site called Gran Dolina at Atapuerca, in a stratum w1.5 m below the Brunhes–Matuyama (B–M) geomagnetic boundary (780 ka) within lithostratigraphic unit TD6. However, most of the meters of fossil- and tool-bear...

  13. 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

  14. 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

  15. Chronology of cholelithiasis. Dating gallstones from atmospheric radiocarbon produced by nuclear bomb explosions

    International Nuclear Information System (INIS)

    We investigated the natural history of cholelithiasis in 59 samples of stones from the gallbladder or common bile duct in 15 patients, using as a tracer for the timing of stone formation the 14C released into the environment during nuclear weapons testing. The ages of the stones were correlated with the dates of onset of symptoms and with other clinical data. None of 11 symptomatic patients had symptoms or complications until at least two years (mean +/- SD, 8.0 +/- 5.1 years) after stone formation began. There was a lag time of 11.7 +/- 4.6 years between initial stone formation and cholecystectomy. The growth rates of stones from 11 symptomatic patients and 4 asymptomatic patients were similar (2.6 +/- 1.4 and 2.6 +/- 1.1 mm per year). Studies of two stones retrieved from the common bile duct showed that one had the same age as a cholecystic stone; the other, removed two years after cholecystectomy, apparently grew in the common bile duct. The long latency period between the formation of gallstones and the onset of symptoms indicates that interruption of the natural progression of gallstone disease is potentially possible with medical therapy

  16. 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.

  17. Holocene history and a thermoluminescence based chronology of coastal dune ridges near Leithfield, North Canterbury, New Zealand

    International Nuclear Information System (INIS)

    Dunes of the Pegasus Bay progradation sequence, North Canterbury, New Zealand, have been assigned previously to three soil-based systems, with age estimates based on inferred rates of coastal progradation and soil development. The present study of the coastal reach between the Kowai and Ashley Rivers, Pegasus Bay, identifies five transverse dune systems. The dune ridge systems trend subparallel to the coast and each system relates to a specific, relict or active, sand and/or mixed sand and gravel beach. A morphogenetic classification based on the relationship of the dunes to the prior strandlines is proposed. This is supported by an absolute (coarse fraction thermoluminescence) chronology of the dune systems. Dune-forming events occurred at c. 6500, <6000, <2600, 1000, and 500 years ago. The transverse dune ridges relate to onshore northeasterly winds. The effective inland penetration of these winds with respect to sand transport is limited to a few hundred metres. Transverse dunes inland of the modern coast are being slowly degraded by the development of low-amplitude parabolic dunes aligned with the northwest foehn wind. These winds are blowing sand back towards the beach. (author). 26 refs., 3 figs., 2 tabs

  18. 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)

    LI; Huaqin(李华芹); CHEN; Fuwen(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.

  19. 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).

  20. Popular Records as Oral Evidence: Creating an Audio Time Line to Examine American History, 1955-1987.

    Science.gov (United States)

    Cooper, B. Lee

    1989-01-01

    Illustrates a method for demonstrating historical chronology using popular songs that comment on a variety of social, political, and economic concerns. Provides an audio time line which uses U.S. recordings from 1955 to 1987 as musical time markers, highlighting such issues as racial discrimination, urban decay, political chicanery and women's…

  1. Chronology and cooling history of the Tianmenshan pluton in South Jiangxi Province and their geological significance

    Institute of Scientific and Technical Information of China (English)

    ZENG Qingtao; MAO Jianren; HU Qing; ZHAO Xilin; YE Haimin

    2008-01-01

    Geochronological studies on the crust-derived Tianmenshan pluton were undertaken by SHRIMP zircon U-Pb dating and Ar-Ar dating of biotite, muscovite and K-feldspar, giving a petrogenetic age of 167 Ma. Owing to the closure systems in different minerals, the cooling history of the pluton can be determined with an age-temperature diagram. The late hydrothermal event has been recognized, which is related probably with mineralization. In terms of the comparative geochronological and petrologic records, it is concluded that there are some constrains on tectonic evolution and that the formation of the Tianmenshan pluton proceeded in a transition period from lndosinian post-orogeny extension to strong compressive tectonics. And the timing of the hydrothermal event matches the compressive climax of the Yanshanian orogeny. The temporal gap between granite emplacement and wolframite mineralization could last 10-20 Ma owing to the low cooling rate of the pluton.

  2. 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...... 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...... 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...

  3. 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

  4. 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.

  5. 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, ...

  6. 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...

  7. 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.

  8. 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 ...

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

    International Nuclear Information System (INIS)

    The 176Lu-176Hf isotope method and its applications in earth sciences are discussed. Greater fractionation of Lu/Hf than Sm/Nd in planetary magmatic processes makes 176Hf/177Hf a powerful geochemical tracer. In general, proportional variations of 176Hf/177Hf exceed those of 143Nd/144Nd by factors of 1.5 to 3 in terrestrial and lunar materials. Lu-Hf studies therefore have a major contribution to make in understanding of terrestrial and other planetary evolution through time, and this is the principal importance of Lu-Hf. New data on basalts from oceanic islands show unequivocally that whereas considerable divergences occur in 176Hf/177Hf-87Sr/ 86Sr and 143Nd/144Nd-87Sr/86Sr diagrams, 176Hf/ 177Hf and 143Nd/144Nd display a single, linear isotopic variation in the suboceanic mantle. These discordant 87Sr/86Sr relationships may allow, with the acquisition of further Hf-Nd-Sr isotopic data, a distinction between processes such as mantle metasomatism, influence of seawater-altered material in the magma source, or recycling of sediments into the mantle. Further applications of the method are discussed. (author)

  10. Chronological changes in microRNA expression in the developing human brain.

    Directory of Open Access Journals (Sweden)

    Michael P Moreau

    Full Text Available MicroRNAs (miRNAs are endogenously expressed noncoding RNA molecules that are believed to regulate multiple neurobiological processes. Expression studies have revealed distinct temporal expression patterns in the developing rodent and porcine brain, but comprehensive profiling in the developing human brain has not been previously reported.We performed microarray and TaqMan-based expression analysis of all annotated mature miRNAs (miRBase 10.0 as well as 373 novel, predicted miRNAs. Expression levels were measured in 48 post-mortem brain tissue samples, representing gestational ages 14-24 weeks, as well as early postnatal and adult time points.Expression levels of 312 miRNAs changed significantly between at least two of the broad age categories, defined as fetal, young, and adult.We have constructed a miRNA expression atlas of the developing human brain, and we propose a classification scheme to guide future studies of neurobiological function.

  11. 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.

  12. Cronología de la erupción implantaria Chronology of the implant eruption

    Directory of Open Access Journals (Sweden)

    Francisco Hernández Altemir

    2010-09-01

    Full Text Available El título ya de por sí tiene que resultarle al lector inmediatamente sospechoso, si no fuera así, sentiríamos desde el principio que no hemos sido capaces de trasmitir nuestro todavía hoy por hoy irrealizable proyecto de poderlo llevar a efecto con fines primero reales y en definitiva prácticos. La idea nos ha surgido quizás fundamentalmente de las películas de ciencia ficción más recientes y nos referimos sobre todo a aquellas que tratan sobre avatares y su entorno.The title in itself has to make the reader suspicious immediately, if it were not so, we would feel from the beginning that we still have been unable to transmit, at this moment in time, to be able to put an unfeasible project into effect, firstly with real aims and finally into practice. The idea has arisen, perhaps mainly due to more recent science fiction films and in particular those that are about Avatars and their environment.

  13. The importance of being "in time" : an integrational linguistic approach

    OpenAIRE

    Zhang, Tian; 張恬

    2015-01-01

    In orthodox linguistics, the relations between time and language are recognized only to a limited extent. Although there have been abundant and substantial investigations into the two topics of temporal deixis and linguistic change (Harris, 2006, pp. 28-29), questions concerning what integrational linguists call “cotemporality” remain largely unexplored. The principle of cotemporality, in integrational linguistic terms, states that “[t]he chronological integration of language with events in o...

  14. 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

  15. 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.

  16. On-and offshore tephrostratigraphy and -chronology of the southern Central American Volcanic Arc (CAVA)

    Science.gov (United States)

    Schindlbeck, J. C.; Kutterolf, S.; Hemming, S. R.; Wang, K. L.

    2015-12-01

    Including the recently drilled CRISP sites (IODP Exp. 334&344) the deep sea drilling programs have produced 69 drill holes at 29 Sites during 9 Legs at the Central American convergent margin, where the Cocos plate subducts beneath the Caribbean plate. The CAVA produced numerous plinian eruptions in the past. Although abundant in the marine sediments, information and data regarding large late Cenozoic explosive eruptions from Costa Rica, Nicaragua, Honduras, El Salvador, and Guatemala remain very sparse and discontinuous on land. We have established a tephrostratigraphy from recent through Miocene times from the unique archive of ODP/IODP sites offshore Central America in which we identify tephra source regions by geochemical fingerprinting using major and trace element glass shard compositions. Here we present first order correlations of ­~500 tephra layers between multiple holes at a single site as well as between multiple sites. We identified ashes supporting Costa Rican (~130), Nicaraguan (17) and Guatemalan (27) sources as well as ~150 tephra layers from the Galápagos hotspot. Within our marine record we also identified well-known marker beds such as the Los Chocoyos tephra from Atitlán Caldera in Guatemala and the Tiribi Tuff from Costa Rica but also correlations to 15 distinct deposits from known Costa Rican and Nicaraguan eruptions within the last 4.1 Ma. These correlations, together with new radiometric age dates, provide the base for an improved tephrochronostratigraphy in this region. Finally, the new marine record of explosive volcanism offshore southern CAVA provides insights into the eruptive history of long-living volcanic complexes (e.g., Barva, Costa Rica) and into the distribution and frequency of large explosive eruptions from the Galápagos hotspot. The integrated approach of Ar/Ar age dating, correlations with on land deposits from CAVA, biostratigraphic ages and sediment accumulation rates improved the age models for the drilling sites.

  17. Toward a molecular understanding of adaptive immunity:A chronology, Part II

    Directory of Open Access Journals (Sweden)

    Kendall A Smith

    2012-11-01

    Full Text Available By 1980 it was obvious that to more fully understand adaptive immunity, one needed to somehow reduce the tremendous complexity of antigen recognition by T cell populations. Thus, there were two developments that resulted in a paradigm shift in immunology, one being the generation of monoclonal antibodies, and the other the development of monoclonal functional antigen-specific T cell lines. For the first time, the cellular reagents became available to ask new questions as to how individual cells comprising the complex cell populations recognize and respond to changes in their molecular environments. The first successful generation of monoclonal T cells depended upon the understanding that antigen renders cells responsive to the antigen non-specific T cell growth factor that came to be termed interleukin-2 (IL-2, which could then be used in propagating large numbers of the progeny of single cells, which in turn could then be used for molecular analyses. Monoclonal functional human T cells were used to immunize mice to generate clone-specific (clonotypic monoclonal antibodies, which then permitted the first biochemical characterizations of the antigen recognition elements of the T cell antigen receptor complex. Moreover, the use of monoclonal cytolytic and helper/inducer human T cell clones essentially proved that the T cell-specific molecules T4 and T8 functioned as accessory molecules in antigen recognition by defining MHC class II or class I restriction respectively. As well, the expression of the T3 molecules, found to be common to all T cells, were shown further to be obligatory for functional antigen-specific T cell signaling. The monoclonal IL-2-dependent T cells were also instrumental in the isolation and purification of the IL-2 molecule to homogeneity, the first interleukin molecule to be identified and characterized. These advances then led to the generation of pure radiolabeled IL-2 molecules that were used to identify the first

  18. [Chronology of tropical dry forest regeneration in Santa Rosa, Guanacaste, Costa Rica. I. Edaphic characteristics].

    Science.gov (United States)

    Leiva, Jorge A; Mata, Rafael; Rocha, Oscar J; Gutiérrez Soto, Marco V

    2009-09-01

    We characterized soil chemical and physical properties in eight tropical dry forest (TDF) successional sites along a time sequence (10, 15, 20, 40, 60 and >100 years) in Santa Rosa, Costa Rica. Seventeen soils were identified, described, and classified in six orders. Most soils were classified as Entisols and Vertisols, but Mollisols, Alfisols, Inceptisols and Ultisols were also present. All soils showed good fertility that did not constrain species richness. High edaphic variation seemed the result of complex interactions among the pyroclastic origin of Santa Rosa ignimbritic plateau (SRIP), the lithological composition and acidity of ignimbritic rocks, the strong seasonality in rainfall, intense hydric and aeolic erosion, topographic variations within the SRIP, and past human intervention. Correlations performed on soils classified as Entisols (soil cations (Ca, Mg, K, Na and CEC) during the first 20 years of forest regeneration, that later recovered in mature TDF sites. Organic matter content did not change significantly along the TDF chrono-sequence. Substantial increments in macro-pores and soil hydraulic conductivity were observed, probably resulting from higher root biomass and turnover in older successional sites. Soil available water and meso-pore abundance were negatively correlated with TDF successional age. Our results indicate that edaphic changes observed along TDF regeneration might have been due to annual fires in pastures and young TDF sites, addition of decaying litter and fine roots as regeneration progressed, milder microclimate conditions during late regeneration in mature TDF sites, increased nutrient cycling, and the predominance of sandy loam textures among the soils examined. These changes in the soil environment with succession may have physiological and phenological consequences on the species appearing at different stages of TDF regeneration. PMID:19928473

  19. The Cenozoic volcanic province of Tibesti (Sahara of Chad): major units, chronology, and structural features

    Science.gov (United States)

    Deniel, C.; Vincent, P. M.; Beauvilain, A.; Gourgaud, A.

    2015-09-01

    Using both field relationships and some absolute ages, the sequence of volcanic units in the Cenozoic Tibesti Volcanic Province (TVP) (Chad) is established as follows: (1) plateau volcanism, between at least 17 and 8 Ma, consisting of flood basalts and silicic lava plugs, with intercalated ignimbritic sheets in the upper basalt succession increasing in amount upwards. Ages decrease from NE to SW, following the migration of the small NW-SE flexures concentrating the feeding dike swarms; (2) Late Miocene large central composite volcanoes exhibiting diverse and original structures. Some of them (Tarso Toon, Ehi Oyé, and Tarso Yéga) are located along a major NNE fault, representing the main tectonic direction in Tibesti since Precambrian times; (3) construction of three large ignimbritic volcanoes, associated with significant updoming of the basement, ending with the collapse of large calderas: Voon (about 5-7 Ma), Emi Koussi (2.4-1.33 Ma), and Yirrigué (0.43 Ma); (4) basaltic activity, starting at about 5-7 Ma, and essentially consisting of cinder cones and associated lava flows (Tarso Tôh, Tarso Ahon, and Tarso Emi Chi); and (5) final volcanic activity represented by post-Yirrigué caldera activity in the Tarso Toussidé Volcanic Complex, and especially Ehi Toussidé (the only active volcano in Tibesti), plus Ehi Timi and Ehi Mousgou volcanoes, similar to Ehi Toussidé. The two tectonic directions controlling some volcanic features of the province correspond to the major old lithospheric structures delimiting the volcanic province, namely, the great NW-SE Tassilian flexure to the SW and a major NE-NNE fault zone to the E. Unusual conditions of uplift and erosion in the TVP enable exceptional exposure of the internal structure of its volcanoes.

  20. Radiocarbon chronology of the last glacial maximum and its termination in northwestern Patagonia

    Science.gov (United States)

    Moreno, Patricio I.; Denton, George H.; Moreno, Hugo; Lowell, Thomas V.; Putnam, Aaron E.; Kaplan, Michael R.

    2015-08-01

    We examine the timing and magnitude of the last glacial maximum (LGM) and the last glacial termination (LGT) in northwestern Patagonia, situated in the middle latitudes of South America. Our data indicate that the main phase of the LGT began with abrupt warm pulses at 17,800 and 17,100 cal yrs BP, accompanied by rapid establishment of evergreen temperate rainforests and extensive deglaciation of the Andes within 1000 years. This response shows that South American middle-latitude temperatures had approached average interglacial values by 16,800 cal yrs BP. The temperature rise in northwestern Patagonia coincides with the beginning of major warming and glacier recession in the Southern Alps of New Zealand at southern mid-latitudes on the opposite side of the Pacific Ocean. From this correspondence, the warming that began at 17,800 cal yrs BP appears to have been widespread in middle latitudes of the Southern Hemisphere, accounting for at least 75% of the total temperature recovery from the LGM to the Holocene. Moreover, this warming pulse is coeval with the first half of the Heinrich Stadial 1 (HS1) in the North Atlantic region. HS1 featured a decline of North Atlantic meridional overturning circulation, a southward shift of the westerly wind belt in both hemispheres and of the Intertropical Convergence Zone, as well as a weakening of the Asian monsoon. Along with the initiating trigger, identifying the mechanisms whereby these opposing climate signals in the two polar hemispheres interacted -whether through an oceanic or an atmospheric bipolar seesaw, or both- lies at the heart of understanding the LGT.

  1. Dating of sediments in the Biscay bay: implication for pollution chronology

    International Nuclear Information System (INIS)

    Important historical informations on the temporal changes of anthropogenic pollution in marine environment can be assessed using sediment analysis. Dating is a crucial prerequisite to reconstruct pollution events, to calculate fluxes, and thus to allow comparison between different sites. This work presents estimates of accumulation rate of sediments in the Bay of Biscay. Fives cores were collected during RIKEAU 2002 cruise on board o/v Thalia in order to study temporal changes in PAH and organo-halogens compounds (PCB, PBDE and PCDD/Fs) content of sediment. We compare chronostratigraphic estimates on cores derived from the natural radionuclide 210Pb in excess with estimates from the known times of introduction of the artificial radionuclide 137Cs to the environment. 210Pb, 226Ra (210Pb in excess = 210Pb - 226Ra) and 137Cs were measured directly by non-destructive gamma spectrometry using a well type γ-detector. Total 210Pb and 226Ra activities vary from 30 to 150 mBq g-1, and 20 to 36 mBq g-1 respectively; 137Cs presents lower levels (-1). Profiles of 210Pbxs present a mixed layer from 2-3 to 10 cm) in the uppermost sediments, followed by an exponential decrease of activities, suitable for the determination of sedimentation rates. Under constant flux and sedimentation rate assumptions, vertical accretion rates derived from 210Pbxs present a large range from nearly 0.1 cm yr-1 up to almost 0.6 cm yr-1. Differences are mainly due to relative position of studied cores regarding the muddy patch. Although the moderate level of 137Cs limits the accuracy of this dating method, profiles of 137Cs with depth strengthen mean rates derived from 210Pbxs data. The implication of these dating on pollutant inputs in sediments of the Bay of Biscay will be discussed. (author)

  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. 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

  4. Luminescence chronology of cave sediments at the Atapuerca paleoanthropological site, Spain.

    Science.gov (United States)

    Berger, G W; Pérez-González, A; Carbonell, E; Arsuaga, J L; Bermúdez de Castro, J-M; Ku, T-L

    2008-08-01

    Ascertaining the timing of the peopling of Europe, after the first out-of-Africa demographic expansion at the end of the Pliocene, is of great interest to paleoanthropologists. One of the earliest direct evidences for fossil hominins in western Europe comes from an infilled karstic cave site called Gran Dolina at Atapuerca, in a stratum approximately 1.5m below the Brunhes-Matuyama (B-M) geomagnetic boundary (780ka) within lithostratigraphic unit TD6. However, most of the meters of fossil- and tool-bearing strata at Gran Dolina have been difficult to date. Therefore, we applied both thermoluminescence (TL) and infrared-stimulated-luminescence (IRSL) multi-aliquot dating methods to fine-silt fractions from sediment samples within Gran Dolina and the nearby Galería cave site. We also applied these methods to samples from the present-day surface soils on the surrounding limestone hill slopes to test the luminescence-clock-zeroing-by-daylight assumption. Within the uppermost 4m of the cave deposits at Gran Dolina, TL and paired TL and IRSL ages range stratigraphically from 198+/-19ka to 244+/-26ka. Throughout Gran Dolina, all luminescence results are stratigraphically self-consistent and, excepting results from two stratigraphic units, are consistent with prior ESR-U-series ages from progressively deeper strata. Thermoluminescence ages culminate at 960+/-120ka approximately 1m below the 780ka B-M boundary. At Galería, with one exception, TL and IRSL ages range stratigraphically downward from 185+/-26ka to 503+/-95ka at the base of the lowermost surface-inwash facies. These results indicate that TL and (sometimes) IRSL are useful dating tools for karstic inwash sediments older than ca. 100ka, and that a more accurate chronostratigraphic correlation is now possible among the main Atapuerca sites (Gran Dolina, Galería, Sima de los Huesos). Furthermore, the oldest TL age of ca. 960ka from Gran Dolina, consistent with biostratigraphic and paleomagnetic evidence, implies

  5. An Instrument for In-situ Triage of Mars 2020 Rover Samples for Organics and Chronology

    Science.gov (United States)

    Anderson, F.; Whitaker, T.; Andrews, J.

    2013-12-01

    We have developed a prototype instrument for triaging samples for elemental chemistry, organics, and Rb-Sr dates on the Mars 2020 Rover. Determining organic content and rock age are key drivers for Mars Sample Return (MSR). By identifying samples with organics, and potentially a range of dates, we increase near-term science return, while maximizing scientific and political will to compel the ultimate return of samples. Though organics have proven difficult to identify in-situ, understanding their distribution and variety could provide key constraints on the possibility of life; on the other hand, datable outcrops are clearly present at a range of potential landing sites, and could provide insight into the evolution of both local and global geology, and the history of solar system bombardment. Our instrument uses laser desorption resonance ionization mass spectrometry (LDRIMS) for Rb-Sr dates, and a subset of the LDRIMS lasers for L2MS measurements of organics. With LDRIMS, a sample is placed in a time-of-flight (TOF) mass spectrometer and surface atoms, molecules, and ions are desorbed with a 213 nm laser. The plume of expanding atoms is present for many μs, during which it is first illuminated with laser light tuned to ionize only Sr, and then 1-3 μs later, Rb . This eliminates isobars for Rb and Sr, and insures that the measured atoms come from the same ablation event, and hence target materials. L2MS uses high-power IR laser ablation to desorb neutral organic molecules, followed by a second, UV laser beam for ionization. Advantages of L2MS include the measurement of a wide array of elements, and it is one of the most sensitive available organic detection methods, with demonstrated detection to 10-18. We have previously demonstrated dates on granites with an average of 1.727×0.087 Ga (MSWD=1; ×0.062 for MSWD=2); both values have a precision and accuracy exceeding that called for by NASA. Finally, we have demonstrated ppm-level detections of organics in the

  6. 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.

  7. Combined ESR/U-series chronology of Acheulian hominid-bearing layers at Trinchera Galeria site, Atapuerca, Spain

    International Nuclear Information System (INIS)

    The Sierra de Atapuerca, northern Spain, is known from many prehistoric and paleontologic sites documenting human prehistory in Europe. Three major sites, Gran Dolina, Galeria 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 Galeria 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 Galeria sites. The authors proposed for Galeria 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 Galeria 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 Galeria 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. (authors)

  8. Relationship between chronological and bone ages and pubertal stage of breasts with bone biomarkers and bone mineral density in adolescents

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    Cristina Maria Teixeira Fortes

    2014-12-01

    Full Text Available OBJECTIVE: To study bone mineral density (BMD in adolescent females according to five groups of chronological age (CA, bone age (BA, and breast development stage (B, and to correlate these parameters with plasma bone biomarkers (BB. METHODS: This was a cross-sectional study performed in 101 healthy adolescent females between 10 and 20 years old. The study variables were: weight, height, body mass index (BMI, CA, B, BA, calcium intake, BMD, and BB. Osteocalcin (OC, bone alkaline phosphatase (BAP, and C-terminal telopeptide (S-CTx were evaluated for BB. BMD was measured using dual energy X-ray absorptiometry (DXA. RESULTS: BMD in lumbar spine, proximal femur, and total body increased with age, and the respective observed averages were: in CA1 (10 years old, 0.631, 0.692, 0.798 g/cm2; in CA2 (11 to 12 years old, 0.698, 0.763, 0.840 g/cm2; in CA3 (13 to 14 years old, 0.865, 0.889, 0.972 g/cm2; in CA4 (15 to 16 years old, 0.902, 0.922, 1.013 g/cm2; and in CA5 (17 to 19 years old, 0.944, 0.929, 1.35 g/cm2. These results showed significant differences between 13 and 14 years of age (CA3 or when girls reached the B3 stage (0.709, 0.832, 0.867 g/cm2. The highest median concentrations of BB were between 10 and 12 years of age when adolescents were in the B2-B3 (p < 0.001. Median BB concentrations decreased in advanced BA and B. CONCLUSIONS: BB concentrations were positively correlated with the peak height velocity and negatively correlated with BMD in the study sites. Increased BMD and BB concentrations were observed in B3.

  9. Late glacial river-bed changes on the Little Hungarian Plain based on preliminary chronological, geological and paleontological data

    Science.gov (United States)

    Sávai, Szilvia; Molnár, Dávid; Sümegi, Pál

    2015-10-01

    Comprehensive chronological, geological and paleontological investigations were conducted as part of archaeological excavations in 2011 and 2012, prior to the construction of the M85 motorway between Gyor and Csorna, Hungary. These studies clearly show that the alluvial fan that underlies much of the Little Hungarian Plain was built up by streams flowing in a southeasterly to northwesterly direction from the nearby Bakony Hills, and continued to form until the end of the last glacial period. The northern part of the fan, now named the Csorna Plain, became inactive (i.e. became a fossil river-bed system) at about 25-15 ka, when the Rába and Marcal rivers changed theirflowdirection fromsouth-north towest-east.As a result of this change in flow direction, the Rába and Marcal rivers became incised, capturing the Bakony stream beds, stopping sediment deposition on the northern side of the alluvial fan (essentially the left bank of the Rába-Marcal river system), although the southern part of the fan continue to form as before. On the northern side of the fan, the sediment surface dried out due to falling groundwater levels, and aeolian sand-drifts began to form. Eventually, accumulation of the sand-drift sediments ceased due to the deposition of loess-type sediments, which fixed the surface, conserved the sand-drift shapes, and contributed to the straightening and eventual canalization of the fluvial channels. Geoarchaeological examinations indicate that the development of present fluvial features were strongly affected by the settlement and tillage activity of human communities on the Csorna Plain.

  10. Correction and validation of 14C chronologies in lake basins, with reference to modern hydrogeological and geochemical systems - examples

    International Nuclear Information System (INIS)

    The primary question before establishing any accurate, confident timescale for palaeo-environmental reconstructions based on lacustrine sediments consists in the definition of the original signature of the TDIC (Total Dissolved Inorganic Carbon) of the lake water from which authigenic compounds are fog ned. This 'carbon' fingerprint of the TDIC may originate from: - The direct exchange with atmospheric CO2; - The admixture of dead dissolved carbon (for example through the leaching of ancient carbonated rocks on the watershed brought to the lake via tributaries) implying the non-equilibrium, and then the ageing, of lake surface waters; - Hydrogeological features of the lake system, such as (i) the connection of the lake waters with extended, shallow aquifers in which the radioactive 14C decay already occurs, or (ii) high hydraulic gradient (mountain landscape) precluding water-rock interaction at the basin scale; - Deep 14C-free CO2 rising along faults in volcanic/tectonic areas, labelled with specific, although wide, ranges of δ 13C values from 0 to -9%o PDB. Previous and on-going works on lakes in key regions have highlighted that, although each lake constitute a specific case study, they can be gathered in groups representing typical cases of distortion of the 14C cycle in lacustrine systems: - eg Lake Bangong (Western Tibet): deep CO2 at the lake bottom, and corrections of the chronology based on the 13C/14C couple and on a regression equation defined on datings... - eg Lake Abiyata (East African Rift): ageing of the authigenic carbonates due to the mixing, at the water/sediment interface, of the lake water and the 14C-depleted regional groundwater; - eg Lake Langano (East African Rift): deep CO2 at the lake bottom and correction of the ageing of the lake surface water by a black-boxes model which provide a step-by-step calculation including the 14C input of atmospheric nuclear weapon tests in the 1960's and the lake turn-over; - eg Lake Aibi (Northern Xinjiang

  11. 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

  12. Quaternary tectonic activity of the Carboneras Fault in the La Serrata range (SE Iberia): Geomorphological and chronological constraints

    Science.gov (United States)

    Moreno, Ximena; Masana, Eulàlia; Pallàs, Raimon; Gràcia, Eulàlia; Rodés, Ángel; Bordonau, Jaume

    2015-11-01

    The Eastern Betic Shear Zone (EBSZ) in Southern Iberia is known to accommodate part of the 4-5 mm/yr convergence between Africa and Iberia, but its seismic hazard is not sufficiently understood for an accurate risk assessment. One of the main structures of the EBSZ, the left-lateral 150 km-long Carboneras Fault, displays no clear instrumental and historical activity despite being morphologically expressive. Detailed geomorphological mapping, geochronological analysis, and structural observation on the La Serrata segment of the Carboneras Fault were designed to investigate its recent evolution. Quaternary sediments and geomorphic features were targeted and 42 new numerical ages were obtained based on 66 samples (thermoluminescence, U-series, 14C, 10Be). The chronological framework of La Serrata was constructed by combining these numerical ages with a conceptual model previously developed in the region, which assumes that alluvial fan aggradation was produced during cold and dry periods (glacials and stadials), whereas stability and phases of calcrete formation were favored during warm and wetter periods (interglacials and interstadials). The spatial distribution of dated alluvial fans suggests an early phase of uplift that probably occurred between 1 Ma and 56.6 ka in the northeastern portion of the study area, whereas in the southwest sector the main uplift phase occurred later than 110.3 ka. A decline in fault activity would have taken place after 30.8 ka. Vertically offset dated units indicate minimum dip-slip rates of 0.05 mm/yr and 0.18 mm/yr, averaged for the last 1 Ma and the last 110.3 ka, respectively. Deflected channels and associated dated units yield a minimum left-lateral strike-slip rate of 1.31 mm/yr, averaged for the last 110.3 ka. The most recent fault movement of the fault could be younger than AD 637. Our results suggest therefore that the Carboneras Fault is among the fastest in Iberia, and should be considered in future hazard analyses.

  13. 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.

  14. 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

  15. 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

    The specific causes and timing of gully incision into swampy meadows throughout the Tablelands of New South Wales, Australia, have been the focus of decades of discussion. Sediment eroded from these gullies is often deposited downstream and referred to as post-settlement alluvium (PSA) as European artefacts such as wire, cans, bottle, and cloth are often found buried in many of these deposits. However, the lack of quantitative data on the timing of gully erosion and subsequent PSA deposition leads to prolonged debate over causes of gully erosion and hampers our ability to understand the total impact of introduced land-use practices on a landscape. As sediment dating techniques such as optically stimulated luminescence (OSL) improve, so does the potential for understanding how and when the Tablelands evolved since the first European surveyors described the landscape. There are only a few applications of these techniques on the Tablelands, however, and they tend to focus on individual sites rather than analysing landscape change in a regional context. We test the commonly held notion that European land-use in the early 19th century caused gully erosion of valley-bottom soils and the associated downstream deposition of PSA on the Tablelands. Here, we present results from a portable OSL reader to identify multiple PSA deposits suitable for burial-age dating, demonstrating the feasibility of this increasingly-accessible field technique in identifying changes in environmental conditions during sediment deposition. Sediment deposited in low-energy swampy meadow environments tends to be well-bleached; the luminescence signal decreases toward zero at the ground surface in modern swampy meadows. After landscape disturbance there is an influx of unbleached sediment and a large (inherited) portable reader luminescence signal is observed in the lowest horizon of PSA deposits, stratigraphically younger than the swampy meadow sediments. This spike in the bulk luminescence up

  16. 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.

  17. Assessment of skeletal age using MP 3 and hand-wrist radiographs and its correlation with dental and chronological ages in children

    OpenAIRE

    Bala M; Pathak A; Jain R

    2010-01-01

    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 can...

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. Index to Nuclear Safety: a technical progress review by chronology, permuted title, and author. Vol. 11(1)--Vol. 18(6)

    International Nuclear Information System (INIS)

    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

  5. 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...

  6. 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

  7. The Times of Archaeology and Archaeologies of Time

    Directory of Open Access Journals (Sweden)

    Andrew Gardner

    2001-11-01

    Full Text Available The subject matter of archaeology as a discipline is explicitly structured by time, and ‘timetravel’ is a common feature of popular discourses about the study of the past. Yet archaeology is also the discipline which, amongst its other theoretical shortcomings, has singularly failed to develop any theory of time. Chronology is ever-present as a measuring tool, but only in rare cases has there been any consideration of this as but one, culturally-specific kind of temporality among many others experienced by people in their daily lives. In this paper, I will discuss various perspectives on archaeological times, including more sophisticated approaches developed since the later 1980s, and argue for an abandoning of the dualism between ‘measured’ and ‘experienced’ times which has emerged in some of these more critical attempts to grapple with the issue. Time is fundamental to archaeology, but not just because we ‘use’ dates. Rather, archaeologists should be able to contribute to wider discussions of time from their understandings of the materialized temporalities of past human agents, and to develop perspectives on the importance of these to the very nature of human social agency as a form of engagement with the world.

  8. 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.

  9. Space-Time--Time

    OpenAIRE

    Ellis, Homer G.

    2002-01-01

    Space-time--time is a natural hybrid of Kaluza's five-dimensional geometry and Weyl's conformal space-time geometry. Translations along the secondary time dimension produce the electromagnetic gauge transformations of Kaluza--Klein theory and the metric gauge transformations of Weyl theory, related as Weyl postulated. Geometrically, this phenomenon resides in an exponential-expansion producing ``conformality constraint'', which replaces Kaluza's ``cylinder condition''. The curvature tensors e...

  10. Use of Dendrochronology for Determining the Chronology of Landslide Activity Along Meadow Run, Shenandoah Valley, Virginia USA

    Science.gov (United States)

    Eaton, L. S.; Yanosky, T. M.; Wieczorek, G. F.

    2003-12-01

    The growth rings of living trees were examined to determine the chronology of landslide activity along Meadow Run, a low-order ungaged stream that emerges from the western flank of the Blue Ridge Mountains of Virginia and flows into the South River in the eastern Shenandoah Valley. At the study site, Meadow Run meanders over a Pleistocene-Quaternary alluvial fan comprised of fresh and weathered sands and cobbles derived from quartzites and sandstones of the Antietam Formation. The alluvium is underlain by the Shady Dolomite, which has limited exposure as saprolite in some stream cuts and slope failures. Stream migration and undercutting of topographically higher fan surfaces creates bluffs up to 20 m in height that show signs of past and recent slope instability. Tilting of trees and slope surfaces indicate that rotation is the dominant type of slope movement; hence, these landslides are termed earth slumps. Two of these slides are contiguous and were investigated in detail. The geomorphology of the downstream slide suggests episodic movement since the mid 1930s. A white oak near the main scarp of the slide shows an abrupt and sustained decrease in ring width beginning in 1937, suggesting that the tree was tilted and root pruned; a sprout from the base of the tilted trunk started to grow no later than 1940. A nearby sprout that began growth no later than 1941 from a tilted black gum supports the general dating of the initial slide. Along the South River at Harriston, floods were recorded in March 1936 (12,600 cfs) and April 1937 (11,700 cfs), suggesting that slope instability along Meadow Run resulted from the undercutting of bluffs by flood waters or from over-saturation of soils during heavy rains. The synchronous formation of reaction wood beginning in the early 1970s in the oak and gum sprouts, and in the parent trunk of a nearby Virginia pine, suggests an episode of slope movement triggered by the peak flow (21,300 cfs) following Hurricane Agnes in June 1972

  11. 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.

  12. A new serial pooling method of shifted tree ring blocks to construct millennia long tree ring isotope chronologies with annual resolution.

    Science.gov (United States)

    Boettger, Tatjana; Friedrich, Michael

    2009-03-01

    The study presents a new serial pooling method of shifted tree ring blocks for the building of isotope chronologies. This method combines the advantages of traditional 'serial' and 'intertree' pooling, and can be recommended for the construction of sub-regional long isotope chronologies with sufficient replication, and on annual resolution, especially for the case of extremely narrow tree rings. For Scots pines (Pinus sylvestris L., Khibiny Low Mountains, NW Russia) and Silver firs (Abies alba Mill., Franconia, Southern Germany), serial pooling of five consecutive tree rings seems appropriate because the species- and site-specific particularities lead to blurs of climate linkages in their tree rings for the period up to ca. five years back. An equivalent to a five-year running means that curve gained on the base annual data sets of single trees can be derived from the analysis of yearly shifted five-year blocks of consecutive tree rings, and therefore, with approximately 20% of the expense. Good coherence of delta(13)C- and delta(18)O-values between calculated means of annual total rings or late wood data and means of five-year blocks of consecutive total tree rings analysed experimentally on most similar material confirms this assumption. PMID:19191128

  13. 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.

  14. Space-Time--Time

    CERN Document Server

    Ellis, H G

    2002-01-01

    Space-time--time is a natural hybrid of Kaluza's five-dimensional geometry and Weyl's conformal space-time geometry. Translations along the secondary time dimension produce the electromagnetic gauge transformations of Kaluza--Klein theory and the metric gauge transformations of Weyl theory, related as Weyl postulated. Geometrically, this phenomenon resides in an exponential-expansion producing ``conformality constraint'', which replaces Kaluza's ``cylinder condition''. The curvature tensors exhibit a wealth of ``interactions'' among geometrical entities with physical interpretations. Unique to the conformally constrained geometry is a sectionally isotropic, ultralocally determined ``residual curvature'', useful in construction of an action density for field equations. A space-time--time geodesic describes a test particle whose rest mass m and electric charge q evolve according to definite laws. The particls's motion is governed by four apparent forces: the Einstein gravitational force, the Lorentz electromagn...

  15. Time over time

    OpenAIRE

    Vicente Navarro, Eduardo

    2006-01-01

    The present essay is designed to be a general introduction to the philosophical problem of time from its very different forms and ways of approaching. In this sense, the article covers the problem from different perspectives and gives a brief account of the plurality and diversity of the time found in the different philosophical definitions, in the different layers of knowledge, in different periods and cultures and also in the different instruments used to measure time itself

  16. Shadow on the steps : time measurement in ancient Israel

    OpenAIRE

    Miano, David Ringo

    2006-01-01

    Many historians and biblical scholars have attempted to make sense of the data found in the Hebrew Bible in order to reconstruct the time measuring systems that were in use in ancient Israel. Some have been more successful than others, but all who have tackled the problem have had difficulties in understanding the systems employed. The usual approach is to ignore the fact that the Bible is a collection of various writings from various times and places and to gather all of the chronological da...

  17. A Feeling for Clay: Japanese Pottery from Ancient to Pre-Modern Times. A Teacher Workshop on May 8, 1993. Teacher's Packet.

    Science.gov (United States)

    Schardt, Molly; And Others

    This packet accompanies a slide series designed to introduce students to the clay pottery works of Japan. The packet includes an essay introduction to the early influences on Japanese pottery, maps of the region, a time line of the chronology of Japan from 2000 B.C. to the present, illustrations of types of kilns, a 18-item bibliography for…

  18. 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

  19. 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

  20. 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

  1. 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.

  2. 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.

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

    OpenAIRE

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

    2014-01-01

    Sedimentary records of plant-wax hydrogen (δD_(wax)) and carbon (δ^(13)C_(wax)) 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 al...

  4. Time-dependent changes of autophagy and apoptosis in lipopolysaccharide-induced rat acute lung injury

    OpenAIRE

    Li Lin; Lijun Zhang; Liangzhu Yu; Lu Han; Wanli Ji; Hui Shen; Zhenwu Hu

    2016-01-01

    Objective(s): Abnormal lung cell death including autophagy and apoptosis is the central feature in acute lung injury (ALI). To identify the cellular mechanisms and the chronology by which different types of lung cell death are activated during lipopolysaccharide (LPS)-induced ALI, we decided to evaluate autophagy (by LC3-II and autophagosome) and apoptosis (by caspase-3) at different time points after LPS treatment in a rat model of LPS-induced ALI. Materials and Methods: Sprague-Dawley ra...

  5. The chronology and tectonic style of landscape evolution along the elevated Atlantic continental margin of South Africa resolved by joint apatite fission track and (U-Th-Sm)/He thermochronology

    Science.gov (United States)

    Wildman, Mark; Brown, Roderick; Beucher, Romain; Persano, Cristina; Stuart, Fin; Gallagher, Kerry; Schwanethal, James; Carter, Andrew

    2016-03-01

    Atlantic-type continental margins have long been considered "passive" tectonic settings throughout the entire postrift phase. Recent studies question the long-term stability of these margins and have shown that postrift uplift and reactivation of preexisting structures may be a common feature of a continental margin's evolution. The Namaqualand sector of the western continental margin of South Africa is characterized by a ubiquitously faulted basement but lacks preservation of younger geological strata to constrain postrift tectonic fault activity. Here we present the first systematic study using joint apatite fission track and apatite (U-Th-Sm)/He thermochronology to achieve a better understanding on the chronology and tectonic style of landscape evolution across this region. Apatite fission track ages range from 58.3 ± 2.6 to 132.2 ± 3.6 Ma, with mean track lengths between 10.9 ± 0.19 and 14.35 ± 0.22 µm, and mean (U-Th-Sm)/He sample ages range from 55.8 ± 31.3 to 120.6 ± 31.4 Ma. Joint inverse modeling of these data reveals two distinct episodes of cooling at approximately 150-130 Ma and 110-90 Ma with limited cooling during the Cenozoic. Estimates of denudation based on these thermal histories predict approximately 1-3 km of denudation coinciding with two major tectonic events. The first event, during the Early Cretaceous, was driven by continental rifting and the development and removal of synrift topography. The second event, during the Late Cretaceous, includes localized reactivation of basement structures as well as regional mantle-driven uplift. Relative tectonic stability prevailed during the Cenozoic, and regional denudation over this time is constrained to be less than 1 km.

  6. 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.

  7. Old times Old times

    Directory of Open Access Journals (Sweden)

    Ubiratan Paiva de Oliveira

    2008-04-01

    Full Text Available In Pinter: A Study of His Plays, Martin Esslin mentions three levels of possible interpretation for Old Times. According to him, Pinter's play could be interpreted on a realistic level, or either representing the male character's dream or a ritual game. He correctly remarks, though, that none of those levels excludes the others, because "... they must co-exist to create the atmosphere of poetic ambivalence on which the image of the play rests..1 In Pinter: A Study of His Plays, Martin Esslin mentions three levels of possible interpretation for Old Times. According to him, Pinter's play could be interpreted on a realistic level, or either representing the male character's dream or a ritual game. He correctly remarks, though, that none of those levels excludes the others, because "... they must co-exist to create the atmosphere of poetic ambivalence on which the image of the play rests..1

  8. 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

  9. Average value of correlated time series, with applications in dendroclimatology and hydrometeorology

    Energy Technology Data Exchange (ETDEWEB)

    Wigley, T.M.L.; Briffa, K.R.; Jones, P.D.

    1984-02-01

    In a number of areas of applied climatology, time series are either averaged to enhance a common underlying signal or combined to produce area averages. How well, then, does the average of a finite number (N) of time series represent the population average, and how well will a subset of series represent the N-series average. We have answered these questions by deriving formulas for 1) the correlation coefficient between the average of N time series and the average of n such series (where n is an arbitrary subset of N) and 2) the correlation between the N-series average and the population. We refer to these mean correlations as the subsammple signal strength (SSS) and the expressed population signal (EPS). They may be expressed in terms of the mean interseries correlation coefficient r-barm as SSS = (R-bar/sub n/,N)/sup 2/roughly-equaln(1+(N-1)r-bar)/N(1+(n+1)r-bar), EPS = (R-bar/sub N/)/sup 2/roughly-equalNr-bar/1+(N-1)r-bar. Similar formulas are given relating these mean correlations to the fractional common variance which arises as a parameter in analysis of variance. These results are applied to determine the increased uncertainty in a tree-ring chronology which results when the number of cores used to produce the chronology is reduced. Such uncertainty will accrue to any climate reconstruction equation that is calibrated using the most recent part of the chronology. The method presented can be used to define the useful length of tree-ring chronologies for climate reconstruction work.

  10. Wavelet analysis of low-frequency variability in oak tree-ring chronologies from east Central Europe

    Science.gov (United States)

    Sen, Asok K.; Kern, Zoltán

    2016-07-01

    This study investigates the low-frequency (interannual and longer period) variability in three hydroclimatic records from east Central Europe. Two of these records consist of climate proxies derived from oak-tree rings in Bakta forest, and Balaton Highlands in Hungary, for the time interval 1783-2003. The third record consists of homogenized instrumental precipitation data from Budapest, Hungary, from 1842 to 2003. Using wavelet analysis, the three time series are analyzed and compared with one another. It is found that all three time series exhibit strong interannual variability at the 2-4 years timescales, and these variations occur intermittently throughout the length of each record. Significant variability is also observed in all the records at decadal timescales, but these variations persist for only two to three cycles. Wavelet coherence among the various time series is used to explore their time-varying correlation. The results reveal significant coherence at the 2-4 years band. At these timescales, the climatic variations are correlated to the tree-ring signal over different time intervals with changing phase. Increased (decreased) contribution of large-scale stratiform precipitation offers a potential explanation for enhanced (faded) coherence at the interannual timescale. Strong coherence was also observed occasionally at decadal timescales, however these coherences did not appear uniformly. These results reinforce the earlier assertion that neither the strength nor the rank of the similarity of the local hydroclimate signals is stable throughout the past two centuries.

  11. 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

  12. Old times Old times

    OpenAIRE

    Ubiratan Paiva de Oliveira

    2008-01-01

    In Pinter: A Study of His Plays, Martin Esslin mentions three levels of possible interpretation for Old Times. According to him, Pinter's play could be interpreted on a realistic level, or either representing the male character's dream or a ritual game. He correctly remarks, though, that none of those levels excludes the others, because "... they must co-exist to create the atmosphere of poetic ambivalence on which the image of the play rests..1 In Pinter: A Study of His Plays, Martin Esslin ...

  13. 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

  14. Palaeomagnetic chronology of the evaporitic sedimentation in the Neogene Fortuna Basin (SE Spain): early restriction preceding the 'Messinian Salinity Crisis'

    NARCIS (Netherlands)

    Dinarès-Turell, Jaume; Ortí, Federico; Playà, Elisabet; Rosell, Laura

    2002-01-01

    The magnetostratigraphic study of the evaporitic Río Chicamo section (240 m) in the Neogene Fortuna Basin (Murcia, southeast Spain) has identified the record of five magnetozones. The most probable correlations with the standard geomagnetic polarity time scale (GPTS) imply that the marine evaporitic

  15. 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

  16. Palaeomagnetic chronology of the evaporitic sedimentation in the Neogene Fortuna Basin (SE Spain): early restriction preceding the 'Messinian Salinity Crisis'

    OpenAIRE

    Dinarès-Turell, Jaume; Ortí, Federico; Playà, Elisabet; Rosell, Laura

    2002-01-01

    The magnetostratigraphic study of the evaporitic Río Chicamo section (240 m) in the Neogene Fortuna Basin (Murcia, southeast Spain) has identified the record of five magnetozones. The most probable correlations with the standard geomagnetic polarity time scale (GPTS) imply that the marine evaporitic sedimentation of this basin was not coeval with the Messinian evaporites of the Sorbas Basin (Almeria, southeast Spain) and the Caltanissetta Basin (central Sicily) (assigned to the reverse Chron ...

  17. “汝阴处士”常秩事迹考%Chang Zhi: A Ruyin Hermit’s Chronology

    Institute of Scientific and Technical Information of China (English)

    袁贝贝

    2012-01-01

    Chang Zhi was a Yingzhou hermit discovered by Oayang Xiu, who was the prefect of Yingzhou District at that time. Because of Ouyang's recommendation and promotion, the imperial court conferred post on Chang several times, but he rejected all. Thus Chang was known as Ruyin Hermit far and wide in the country. However, Chang became an official while Wang Anshi carried and the New Law, which disappointed Ouyang deeply. During the time as an official, Chang made no achievements and had a bad reputation, disclosing a strong ironic sense against the past fame of Ruyin Hermit.%常秩是欧阳修知颍州时发现的当地隐士。由于欧阳修的举荐和推扬,朝廷多次授官,常秩均辞不受,以“汝阴处士”名闻天下。可是,在王安石推行“新法”之时,常秩却入朝为官了。此举令欧阳修大失所望。常秩为官时并无建树,而且名声不佳,与此前的“汝阴处士”相比,具有强烈的讽刺意味。

  18. Quantum mechanics of time travel through post-selected teleportation

    International Nuclear Information System (INIS)

    This paper discusses the quantum mechanics of closed-timelike curves (CTCs) and of other potential methods for time travel. We analyze a specific proposal for such quantum time travel, the quantum description of CTCs based on post-selected teleportation (P-CTCs). We compare the theory of P-CTCs to previously proposed quantum theories of time travel: the theory is inequivalent to Deutsch's theory of CTCs, but it is consistent with path-integral approaches (which are the best suited for analyzing quantum-field theory in curved space-time). We derive the dynamical equations that a chronology-respecting system interacting with a CTC will experience. We discuss the possibility of time travel in the absence of general-relativistic closed-timelike curves, and investigate the implications of P-CTCs for enhancing the power of computation.

  19. An extended commentary on Stephen E. Nash, editor. 2000. It's About Time: A History of Archaeo­logical Dating in North America, University of Utah Press, Salt Lake City

    OpenAIRE

    David L. Browman

    2001-01-01

    The It's About Time volume, which focuses upon the issues of historiography and chronology in North American archaeology, is the publication of the papers from a 1997 Society for American Archaeology symposium. The papers are for the most part on the development of various daring techniques (such as archaeomagnetism, dendrochronology, radiocarbon, or thermoluminescence) from an archaeological perspective, but there is ...

  20. A cosmogenic 3He chronology of late Quaternary glacier fluctuations in North Island, New Zealand (39°S)

    Science.gov (United States)

    Eaves, Shaun R.; N. Mackintosh, Andrew; Winckler, Gisela; Schaefer, Joerg M.; Alloway, Brent V.; Townsend, Dougal B.

    2016-01-01

    Mountain glaciers advance and retreat primarily in response to changes in climate. Establishing the timing and magnitude of mountain glacier fluctuations from geological records can thus help to identify the drivers and mechanisms of past climate change. In this study, we use cosmogenic 3He surface exposure dating and tephrochronology to constrain the timing of past glaciation on Tongariro massif in central North Island, New Zealand (39°S). Exposure ages from moraine boulders show that valley glaciation persisted between c. 30-18 ka, which coincides with the global Last Glacial Maximum. Reinterpretation of moraine tephrostratigraphy, using major element geochemistry analysis, shows that ice retreat and climatic amelioration at the last glacial termination was well underway prior to 14 ka. The equilibrium line altitude in central North Island, during the Last Glacial Maximum, was c. 1400-1550 m above sea level, which is c. 930-1080 m lower than present. Considering the uncertainties in the glacial reconstruction and temperature lapse rates, we estimate that this equilibrium line altitude lowering equates to a temperature depression of 5.6 ± 1.1 °C, relative to present. Our mapping and surface exposure dating also show evidence for an earlier period of glaciation, of similar magnitude to the Last Glacial Maximum, which culminated prior to 57 ka, probably during Marine Isotope Stage 4. Good agreement between the timing and magnitude of glacier fluctuations in central North Island and the Southern Alps indicate a response to a common climatic forcing during the last glacial cycle.

  1. Epiphyseal maturity indicators at the knee and their relationship to chronological age: results of an Irish population study.

    LENUS (Irish Health Repository)

    O'Connor, Jean E

    2013-09-01

    Skeletal maturation is divisible to three main components; the time of appearance of an ossification center, its change in morphology and time of fusion to a primary ossification center. With regard to the knee, the intermediate period between appearance and fusion of the ossification centers extends over a period of greater than 10 years. This study aims to investigate radiographically the age at which morphological changes of the epiphyses at the knee occur in a modern Irish population. Radiographs of 221 subjects (137 males; 84 females) aged 9-19 years were examined. Seven nonmetric indicators of maturity were assessed using criteria modified from the Roche, Wainer, and Thissen method and Pyle and Hoerr\\'s atlas of the knee. Reference charts are presented which display the timeline for each of the grades of development of the seven indicators. Mean age was found to increase significantly with successive grades of development of each of the seven indicators. A significant difference was noted between males and females at the same grade of development for six of the seven indicators. The narrowest age range reported for a single grade of development was 2.2 years for Grade 2 of development of the tibial tuberosity for males. The information on changing morphology of the epiphyses at the knee in the present study may provide an adjunct to methods used for evaluation of skeletal maturity before surgery for orthopedic disorders or to evaluate skeletal age in clinical scenarios where either delayed or precocious skeletal maturation is suspected.

  2. Phylogenetic Position and Molecular Chronology of a Colonial Green Flagellate, Stephanosphaera pluvialis (Volvocales, Chlorophyceae), among Unicellular Algae.

    Science.gov (United States)

    Munakata, Hidehito; Nakada, Takashi; Nakahigashi, Kenji; Nozaki, Hisayoshi; Tomita, Masaru

    2016-05-01

    The genus Balticola comprises a group of unicellular green flagellate algae and is composed of four species formerly classified in the genus Haematococcus. Balticola is closely related to a colonial green flagellate, Stephanosphaera pluvialis. Although the phylogeny among these genera was previously investigated based on two nuclear gene sequences, the phylogenetic sister of S. pluvialis has yet to be determined. In the present study, the species diversity of Balticola and Stephanosphaera was investigated using 18S rRNA gene sequences, and phylogenetic analyses of combined nuclear and chloroplast gene sequences were performed to understand the evolutionary origin of coloniality in Stephanosphaera. The divergence times of four colonial volvocalean flagellates from their respective unicellular sisters were also estimated. Six Balticola genotypes and a single Stephanosphaera genotype were recognized, and one Balticola genotype was resolved as the sister of S. pluvialis, showing that Balticola is a nonmonophyletic genus. The divergence time of Stephanosphaera from its nearest Balticola relative was estimated to be 4-63 million years ago, and these genera represent the most recently diverged pair of unicellular and colonial flagellates among the Volvocales. PMID:26595722

  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. Sedimentation rate and chronology of As and Zn in sediment of a recent former tin mining lake estimated using Pb-210 dating technique

    International Nuclear Information System (INIS)

    Sedimentation in lake occurred through run-off from the land surface and settles on the bottom lake. Past mining activities might enhance sedimentation process in the former tin mining lakes either through natural or human activities. Former tin mining lakes were suspected to have high sedimentation rate due undisturbed environment for almost 50 years. To estimate sedimentation rate and metals contamination in this lake, Pb-210 dating technique was used. Two sediments cores were sampled using gravity corer from a former tin mining lake then analyzed using alpha-spectrometry and Neutron Activation Analysis (NAA). From this study, the results showed the sedimentation rate for sediment cores S1 and S2 are 0.26 cm y-1 and 0.23 cmy-1 respectively. According to sediment chronological sequences, high concentrations of As and Zn in the upper layer indicated that human activities contributed to these metals contamination in the lake sediment. Sedimentation rate and metals contamination possibly due to recent anthropogenic activities around the lake such as human settlement, farming and agricultures activities since the ceased of mining activities a few decades ago. (author)

  5. 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.)

  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. Palaeomagnetic secular variation and relative field intensity in pleistocene lacustrine sediments in the U.S. great basin as chronologic tools for dating climate in western north America

    International Nuclear Information System (INIS)

    Complete text of publication follows. Since the end of the 19th Century when first it was reported that large pluvial lakes formed during the Pleistocene in the U.S. Great Basin (Russell, 1885), the sediments deposited by some of those lakes have been used to study climate in western North America back about 3 m.y. (Smith et al., 1983, Morrison, 1991: many others). That research includes mineralogic, isotopic, geochemical, and sedimentologic data; radiometric dates; lacustrine fossils; volcanic ashes; and a record of long-term behaviour (secular variation) and excursions (Pringle Falls, Laschamp, and Mono Lake) of the palaeomagnetic field. In an attempt to establish an accurate chronology for the palaeoclimate in western North America during the past approximately 50,000 years, I will compare the records of palaeomagnetic directions for Pyramid Lake (the remnant of Lake Lahontan in northwestern Nevada)(Benson et al., 2008), Mono Lake (the remnant of Lake Russell in east-central California)(Lund et al., 1988; Zimmerman et al., 2006), and Searles Lake in the southeastern Great Basin (Liddicoat et al., 2008) with other records of palaeomagnetic field behaviour, especially the relative palaeomagnetic field intensity for the North and South Atlantic oceans (Laj et al., 2000; Stoner et al., 2004). This is possible because large- and small-scale fluctuations occur in the records that are distinctive and often are common to all.

  8. 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)

  9. 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.

  10. 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.

  11. Reconstruction of chronology of the 137 Cs and chloro organic pollutants input to the western Black Sea deep sediments (from 1940 s to 1990 s)

    International Nuclear Information System (INIS)

    The 137 Cs was used for dating different layers of the surface bottom sediments in the deep water western Black Sea area. The obtained sedimentation rate was 0.42 ±0.14 mm centre dot yr-1 and corresponding sediment accumulation rate was 69.8 g centre dot m-2 centre dot yr-1. These results are in good agreement with those obtained earlier with the use of other methods. The obtained dat have made possible the chronological tracing of both 137 Cs fall-out and high toxic chloro organic compounds input to the Black Sea anaerobic basin for the whole period of their existence in the biosphere. Three main phases of the 137 Cs input to deep bottom sediments were traced. The first and second phases were in good agreement with the most active atmospheric nuclear weapon testing periods (1945-59 and 1960-63 years), and the third one - with the Chernobyl accident in 1986. The largest flux of137 Cs (14.1 ± 3.1 Bq centre dot m-2 yr-1)corresponded to 1986. The highest chloro organic pollutant input to the Black Sea was in 70 s. Its further decrease was apparently caused by the Danube river-bed damming with Iron Gate in 1970

  12. Remote Sensing Data with the Conditional Latin Hypercube Sampling and Geostatistical Approach to Delineate Landscape Changes Induced by Large Chronological Physical Disturbances

    Directory of Open Access Journals (Sweden)

    Yu-Pin Lin

    2009-01-01

    Full Text Available This study applies variogram analyses of normalized difference vegetation index (NDVI images derived from SPOT HRV images obtained before and after the ChiChi earthquake in the Chenyulan watershed, Taiwan, as well as images after four large typhoons, to delineate the spatial patterns, spatial structures and spatial variability of landscapes caused by these large disturbances. The conditional Latin hypercube sampling approach was applied to select samples from multiple NDVI images. Kriging and sequential Gaussian simulation with sufficient samples were then used to generate maps of NDVI images. The variography of NDVI image results demonstrate that spatial patterns of disturbed landscapes were successfully delineated by variogram analysis in study areas. The high-magnitude Chi-Chi earthquake created spatial landscape variations in the study area. After the earthquake, the cumulative impacts of typhoons on landscape patterns depended on the magnitudes and paths of typhoons, but were not always evident in the spatiotemporal variability of landscapes in the study area. The statistics and spatial structures of multiple NDVI images were captured by 3,000 samples from 62,500 grids in the NDVI images. Kriging and sequential Gaussian simulation with the 3,000 samples effectively reproduced spatial patterns of NDVI images. However, the proposed approach, which integrates the conditional Latin hypercube sampling approach, variogram, kriging and sequential Gaussian simulation in remotely sensed images, efficiently monitors, samples and maps the effects of large chronological disturbances on spatial characteristics of landscape changes including spatial variability and heterogeneity.

  13. K-AR chronology of the ultimate activity of Piton des Neiges volcano, Reunion Island, Indian Ocean

    International Nuclear Information System (INIS)

    Potassium-argon measurements were made on 17 samples from the ultimate stage of activity of the Piton des Neiges volcano, which corresponds to a differentiated series with lavas varying from basalt to quartz trachyte. Samples were selected as a function of their stratographic position and their representativity of magmatic evolution. The technology used to date young volcanic rocks (Pleistocene) by K-Ar is described and discussed because of its reliability in the analysis of modern lavas and because of the agreement of the results with the available stratigraphic control. The data, together with those previously obtained by McDougall, yield ages ranging between 330.000 and 30.000 years, with two mainly effusive periods separated by a phase of instability of chiefly explosive volcanism around 190.000 to 150.000 years ago. A rough correlation between the chemical evolution of the lavas and time is established. (orig./ME)

  14. Spatial-temporal analysis on climate variation in early Qing dynasty (17th -18th century) using China's chronological records

    Science.gov (United States)

    Lin, Kuan-Hui Elaine; Wang, Pao-Kuan; Fan, I.-Chun; Liao, Yi-Chun; Liao, Hsiung-Ming; Pai, Pi-Ling

    2016-04-01

    Global climate change in the form of extreme, variation, and short- or mid-term fluctuation is now widely conceived to challenge the survival of the human beings and the societies. Meanwhile, improving present and future climate modeling needs a comprehensive understanding of the past climate patterns. Although historical climate modeling has gained substantive progress in recent years based on the new findings from dynamical meteorology, phenology, or paleobiology, less known are the mid- to short-term variations or lower-frequency variabilities at different temporal scale and their regional expressions. Enabling accurate historical climate modeling would heavily rely on the robustness of the dataset that could carry specific time, location, and meteorological information in the continuous temporal and spatial chains. This study thus presents an important methodological innovation to reconstruct historical climate modeling at multiple temporal and spatial scales through building a historical climate dataset, based on the Chinese chronicles compiled in a Zhang (2004) edited Compendium of Chinese Meteorological Records of the Last 3,000 Years since Zhou Dynasty (1100BC). The dataset reserves the most delicate meteorological data with accurate time, location, meteorological event, duration, and other phonological, social and economic impact information, and is carefully digitalized, coded, and geo-referenced on the Geographical Information System based maps according to Tan's (1982) historical atlas in China. The research project, beginning in January 2015, is a collaborative work among scholars across meteorology, geography, and historical linguistics disciplines. The present research findings derived from the early 100+ years of the Qing dynasty include the following. First, the analysis is based on the sampling size, denoted as cities/counties, n=1398 across the Mainland China in the observation period. Second, the frequencies of precipitation, cold

  15. Fluvial fan evolution during Late Quaternary climate changes: field and chronological constraints from the Indo-Gangetic basin

    Science.gov (United States)

    Singh, A.; Gupta, S.; Sinha, R.; Densmore, A.; Thomsen, K. J.; Nayak, N.; Joshi, S. K.; van Dijk, W. M.; Buylaert, J. P.; Mondal, S.; Kumar, D.; Mason, P. J.; Murray, A. S.; Kumar, M.; Shekhar, S.; Rai, S. P.

    2015-12-01

    The stratigraphic evolution of fluvial fans is to a large extent governed by channel avulsion. Spatial variations in alluvial architecture are influenced by avulsion magnitude and frequency. However due to the absence of long-term chronostratigraphic records of fan stratigraphy, it has proved difficult to test patterns of fan evolution against records of climate variability. In order to understand the processes of channel avulsion during fan evolution, it is important to determine the spatio-temporal pattern of fluvial channel aggradation, incision, and migration. In this study, we reconstruct the shallow sub-surface alluvial stratigraphy of fluvial fan systems formed by the major Himalayan rivers, the Sutlej and Yamuna, in the northwestern Indo-Gangetic basin. We map the spatial distribution of channel sand bodies deposited by these rivers and develop a chronostratigraphic model for the fluvial succession in a depositional dip perpendicular transect. Sediment cores up to ~50 m deep along two transects are used to reconstruct the shallow stratigraphy of the fan systems. Discontinuous channel sand bodies are separated by floodplain fines which occasionally show weak pedogenesis that mark the end of episodes of channel aggradation. Optically stimulated luminescence (OSL) dating is used to bracket the timing of channel-filling episodes, and their spatial distribution. Mapping of sand bodies coupled with chronostratigraphic constraints allows reconstruction of channel migration patterns and their timing across the Sutlej-Yamuna fans. Chronostratigraphy permits temporal correlation with published measures of monsoon variability. We find that fluvial aggradation at the western end of studied transects, near the middle of the Sutlej fan, terminated around ~20 ka. We also show that abandonment of the paleo-Sutlej and major fan-scale avulsion occurred after ~15 ka, and was followed by formation of incised valleys that confined the modern fluvial system in northwestern Indo

  16. A 615 m.y. age of the Bleida granodiorite, and its implications to the chronology of Panafrican tectonic, metamorphic and magmatic phases in the Moroccan Anti-Atlas

    International Nuclear Information System (INIS)

    A 615+-12 m.y. age is obtained by U-Pb method on zircons extracted from the granodiorite of Bleida (Anti-Atlas, Morocco). This age which is in good agreement with U-Pb and Rb-Sr previous data, argues for the occurrence of the panafrican orogeny in the Anti-Atlas and contributes to define the chronology of the typical features of this orogenic belt

  17. Chronology and backtracking of oil slick trajectory to source in offshore environments using ultraspectral to multispectral remotely sensed data

    Science.gov (United States)

    Lammoglia, Talita; Souza Filho, Carlos Roberto de

    2015-07-01

    Offshore natural seepage confirms the occurrence of an active petroleum system with thermal maturation and migration, regardless its economic viability for petroleum production. Ocean dynamics, however, impose a challenge for correlation between oil seeps detected on the water surface and its source at the ocean floor. This hinders the potential use of seeps in petroleum exploration. The present study aims to estimate oil exposure time on the water surface via remote sensing in order to help locating ocean floor seepage sources. Spectral reflectance properties of a variety of fresh crude oils, oil films on water and oil-water emulsions were determined. Their spectral identity was used to estimate the duration of exposure of oil-water emulsions based on their temporal spectral responses. Laboratory models efficiently predicted oil status using ultraspectral (>2000 bands), hyperspectral (>300 bands), and multispectral (oil seepage recorded by the ASTER sensor on the Brazilian coast was used to test the designed predictive model. Results indicate that the model can successfully forecast the timeframe of crude oil exposure in the ocean (i.e., the relative "age" of the seepage). The limited spectral resolution of the ASTER sensor, though, implies less accurate estimates compared to higher resolution sensors. The spectral libraries and the method proposed here can be reproduced for other oceanic areas in order to approximate the duration of exposure of noticeable natural oil seepages. This type of information is optimal for seepage tracing and, therefore, for oceanic petroleum exploration and environmental monitoring.

  18. Distal tephras of the eastern Lake Victoria basin, equatorial East Africa: correlations, chronology and a context for early modern humans

    Science.gov (United States)

    Blegen, Nick; Tryon, Christian A.; Faith, J. Tyler; Peppe, Daniel J.; Beverly, Emily J.; Li, Bo; Jacobs, Zenobia

    2015-08-01

    The tephrostratigraphic framework for Pliocene and Early Pleistocene paleoanthropological sites in East Africa has been well established through nearly 50 years of research, but a similarly comprehensive framework is lacking for the Middle and particularly the Late Pleistocene. We provide the first detailed regional record of Late Pleistocene tephra deposits associated with artifacts or fossils from the Lake Victoria basin of western Kenya. Correlations of Late Pleistocene distal tephra deposits from the Wasiriya beds on Rusinga Island, the Waware beds on Mfangano Island and deposits near Karungu, mainland Kenya, are based on field stratigraphy coupled with 916 electron microprobe analyses of eleven major and minor element oxides from 50 samples. At least eight distinct distal tephra deposits are distinguished, four of which are found at multiple localities spanning >60 km over an approximately north to south transect. New optically stimulated luminescence dates help to constrain the Late Pleistocene depositional ages of these deposits. Our correlation and characterization of volcaniclastic deposits expand and refine the current stratigraphy of the eastern Lake Victoria basin. This provides the basis for relating fossil- and artifact-bearing sediments and a framework for ongoing geological, archaeological and paleontological studies of Late Pleistocene East Africa, a crucial time period for human evolution and dispersal within and out of Africa.

  19. An integrated approach to the assessment of pollutant delivery chronologies to impacted areas: Hg in the Augusta Bay (Italy).

    Science.gov (United States)

    Bellucci, Luca Giorgio; Giuliani, Silvia; Romano, Stefania; Albertazzi, Sonia; Mugnai, Cristian; Frignani, Mauro

    2012-02-21

    Assessing pollution levels and trends in heavily impacted environments is important but hardly achievable due to the difficulty of recovering suitable undisturbed sediment records. An integrated approach is here presented to solve this kind of problem. It was adopted in the Augusta Bay (Italy) for the study of Hg historical inputs and present trends. Archive information on dredging and mud disposal, together with bathymetry and high-resolution seismic profiles, were used to identify suitable sampling sites. Undisturbed sediment cores were collected in the port and bay. Sediments were analyzed for depth distributions of radiotracers ((210)Pb and (137)Cs), Hg, and main sediment parameters (magnetic susceptibility, grain size, dry bulk density, mineralogy, and organic carbon and nitrogen contents). Hexachlorobenzene (HCB) was also analyzed as an additional time tracer, since its production history in the area was well-known. Results show that peak Hg contamination (up to 575 mg·kg(-1)) was reached in the 1970s. Technological improvements and waste treatment in the following years determined a consistent decrease, but high concentrations still affect surficial sediments (0.25-92 mg·kg(-1)). Hg-HCB correlation suggests that this situation is likely the effect of resuspension and redistribution of deep sediments by dredging and naval traffic. PMID:22233219

  20. Time Compression

    OpenAIRE

    Aadland, David; Shaffer, Sherrill

    2012-01-01

    Economists have generally ignored the notion that perceived time may differ from clock time. Borrowing from the behavioral psychology literature, we investigate the case of time compression whereby perceived time passes more quickly than actual time. A framework is presented to embed time compression in economic models. We then apply the principle to a standard lifecycle permanent income model with endogenous labor. Time compression provides an alternative explanation of why older indi...

  1. The archaeology, chronology and stratigraphy of Madjedbebe (Malakunanja II): A site in northern Australia with early occupation.

    Science.gov (United States)

    Clarkson, Chris; Smith, Mike; Marwick, Ben; Fullagar, Richard; Wallis, Lynley A; Faulkner, Patrick; Manne, Tiina; Hayes, Elspeth; Roberts, Richard G; Jacobs, Zenobia; Carah, Xavier; Lowe, Kelsey M; Matthews, Jacqueline; Florin, S Anna

    2015-06-01

    Published ages of >50 ka for occupation at Madjedbebe (Malakunanja II) in Australia's north have kept the site prominent in discussions about the colonisation of Sahul. The site also contains one of the largest stone artefact assemblages in Sahul for this early period. However, the stone artefacts and other important archaeological components of the site have never been described in detail, leading to persistent doubts about its stratigraphic integrity. We report on our analysis of the stone artefacts and faunal and other materials recovered during the 1989 excavations, as well as the stratigraphy and depositional history recorded by the original excavators. We demonstrate that the technology and raw materials of the early assemblage are distinctive from those in the overlying layers. Silcrete and quartzite artefacts are common in the early assemblage, which also includes edge-ground axe fragments and ground haematite. The lower flaked stone assemblage is distinctive, comprising a mix of long convergent flakes, some radial flakes with faceted platforms, and many small thin silcrete flakes that we interpret as thinning flakes. Residue and use-wear analysis indicate occasional grinding of haematite and woodworking, as well as frequent abrading of platform edges on thinning flakes. We conclude that previous claims of extensive displacement of artefacts and post-depositional disturbance may have been overstated. The stone artefacts and stratigraphic details support previous claims for human occupation 50-60 ka and show that human occupation during this time differed from later periods. We discuss the implications of these new data for understanding the first human colonisation of Sahul. PMID:25957653

  2. Evidence for leptonic CP phase from NOνA, T2K and ICAL: A chronological progression

    International Nuclear Information System (INIS)

    We study the synergy between the long-baseline (LBL) experiments NOνA and T2K and the atmospheric neutrino experiment ICAL@INO for obtaining the first hint of CP violation in the lepton sector. We also discuss how precisely the leptonic CP phase (δCP) can be measured by these experiments. The CP sensitivity is first described at the level of oscillation probabilities, discussing its dependence on the parameters – θ13, mass hierarchy and θ23. In particular, we discuss how the precise knowledge or lack thereof of these parameters can affect the CP sensitivity of LBL experiments. We follow a staged approach and analyze the δCP sensitivity that can be achieved at different points of time over the next 15 years from these LBL experiments alone and/or in conjunction with ICAL@INO. We find that the CP sensitivity of NOνA/T2K is enhanced due to the synergies between the different channels and between the two experiments. On the other hand the lack of knowledge of hierarchy and octant makes the CP sensitivity poorer for some parameter ranges. Addition of ICAL data to T2K and NOνA can exclude these spurious wrong-hierarchy and/or wrong-octant solutions and cause a significant increase in the range of δCP values for which a hint of CP violation can be achieved. In fact in parameter regions unfavourable for NOνA/T2K, we may get the first evidence of CP violation by adding the ICAL data to these. Similarly the precision with which δCP can be measured also improves with inclusion of ICAL data

  3. Chronological studies of tree-rings from the Amazon Basin using thick target PIXE and proton backscattering analysis

    International Nuclear Information System (INIS)

    A tree-core sample (Aspidosperma obscurinervium, popular name: 'pequia marfim') about 161 years old (cut in 1990), from the Ducke Reserve at the Amazon Basin, Manaus, Brazil was analyzed by PIXE (Particle Induced X-ray Emission) and proton backscattering in 136 different spots along its life. Twenty-two elements plus the density of the wood were measured (C, O, H, Al, Si, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Sr, Co, Rb, W and Pb). Average C, O, and H results (49.77% ± 0.15%, 44.29% ± 0.14% and 5.95% ± 0.12%, respectively) compare well with literature values for the biomass in the Amazon region. The variability of trace elements along the tree rings showed important features that could be caused by modifications in the environment during the life of the tree. The well behaved variability of some trace elements (like K, P, Mn, Ca, etc.) seems to reflect the physiological response of the tree to external changes in the environment. The concentration of K varied from about 4 up to 2000 ppm in a given period of the life of the tree. The same period also shows important changes in the bulk composition and structure of the rings (e.g. C and density series). Multivariate statistical methods (cluster and factor analyses) were used for data interpretation, helping in the separation of periods of important transformations in the tree. The elemental time series is compared with historical records of regional development and with some global events that could possibly affect the tree. The period of maximum variation in the elemental concentrations appears to be related to the Brazilian rubber boom (1859-1912), responsible for several transformations in the Amazon region. In particular in the Manaus region, large development has occurred in the beginning of the 20th century, which are reflected in the results of this tree-core analysis

  4. A first 10Be cosmogenic glacial chronology from the High Atlas, Morocco, during the last glacial cycle.

    Science.gov (United States)

    Fink, David; Hughes, Philip; Fenton, Cassie

    2014-05-01

    Glacial geomorphological mapping, 10Be cosmogenic exposure ages of 21 erratics from cirque-valley systems and paleo-glacier climate modelling in the High Atlas Mountains, Morocco (31.1° N, 7.9° W), provides new and novel insights as to the history and evolution of the largest desert region on Earth. The Atlas Mountains display evidence of extensive and multiple Late Pleistocene glaciations whose extent is significantly larger than that recognised by previous workers. The largest glaciers formed in the Toubkal massif where we find 3 distinct phases of glacial advances within the last glacial cycle. The oldest moraines occurring at the lowest elevations have yielded eight 10Be ages ranging from 30 to 88 ka. Six of eight samples from moraines at intermediate elevations gave ages of 19 to 25 ka (2 outliers) which correlates well with the global Last Glacial Maximum (ca. 26-21 ka) and the last termination during marine isotope stage 2. Five erratics from the youngest and most elevated moraines yielded a suite of normally distributed exposure ages from 11 to 13 ka which supports a correlation with the northern hemisphere Younger Dryas (12.9-11.7 ka). The glacial record of the High Atlas effectively reflects moisture supply to the north-western Sahara Desert and can provide an indication of shifts between arid and pluvial conditions. The plaeo equilibrium line altitudes (ELA) of these three glacier phases was more than 1000 m lower than the predicted ELA based on today's temperatures. Glacier-climate modelling indicates that for each of these glacier phases climate was not only significantly cooler than today, but also much wetter. The new evidence on the extent, timing and palaeoclimatic significance of glaciations in this region has major implications for understanding moisture transfer between the North Atlantic Ocean and the Sahara Desert during Pleistocene cold stages.

  5. Provenance shift in Cambrian mid-Baltica: detrital zircon chronology of Ediacaran–Cambrian sandstones in Estonia

    Directory of Open Access Journals (Sweden)

    Yukio Isozaki

    2014-12-01

    Full Text Available In order to clarify the tectono-sedimentary history of Paleozoic Baltica, age spectra of detrital zircon grains from the Ediacaran (Kotlin Regional Stage and Lower Cambrian sandstones (lowermost Lontova and Lükati formations in western Estonia in central Baltica were analyzed by LA-ICPMS. The abundant occurrence of Archean to Mesoproterozoic (2800–1000 Ma zircon grains was confirmed in all samples. The new data provided the following information on the provenance of siliciclastic material as well as a major change in the sedimentary regime of the Paleo-Baltic basin during the Early Cambrian: (1 the Ediacaran–Lower Cambrian Paleo-Baltic basin received abundant terrigenous clastics from the core of Baltica underlain by the Archean–Mesoproterozoic crystalline crust, (2 the exposed surface area of the 1600 Ma Rapakivi granites apparently was more extensive during the Ediacaran–Early Cambrian than at present, (3 a major re-organization of the basin geometry occurred in the middle Early Cambrian (ca 530–515 Ma in central Baltica, inducing a change in the sediment supply system, (4 in contrast to the total absence of Neoproterozoic detrital zircon grains before the middle Early Cambrian, their sudden appearance at this time, together with consistent occurrence at least until the mid-Devonian, suggests a significant uplift event located in southeast Baltica and/or in a more easterly land domain (e.g., in Sarmatia, (5 possible sources for the Neoproterozoic zircon grains include the peripheral mobile belts with pan-African signatures around Baltica, e.g., the so-called Gondwanan fragments along the Tornquist margin to the southwest and the Timanian belt along the northeastern margin.

  6. Chronological Changes of C-Reactive Protein Levels Following Uncomplicated, Two-Staged, Bilateral Deep Brain Stimulation

    Science.gov (United States)

    Kim, Jae-hun; Ha, Sang-woo; Choi, Jin-gyu

    2015-01-01

    Objective The occurrence of acute cerebral infection following deep brain stimulation (DBS) is currently being reported with elevation of C-reactive protein (CRP) level. The aim of the present study was to establish normal range of the magnitude and time-course of CRP increases following routine DBS procedures in the absence of clinical and laboratory signs of infection. Methods A retrospective evaluation of serial changes of plasma CRP levels in 46 patients undergoing bilateral, two-staged DBS was performed. Because DBS was performed as a two-staged procedure involving; implantation of lead and internal pulse generator (IPG), CRP was measured preoperatively and postoperatively every 2 days until normalization of CRP (post-lead implantation day 2 and 4, post-IPG implantation day 2, 4, and 6). Results Compared with preoperative CRP levels (0.12±0.17 mg/dL, n=46), mean CRP levels were significantly elevated after lead insertion day 2 and 4 (1.68±1.83 mg/dL, n=46 and 0.76±0.38 mg/dL, n=16, respectively, p0.05). Mean CRP levels after IPG implantation were significantly higher in patients whose IPGs were implanted at post-lead day 3 than those at post-lead day 5-6 (3.99±2.80 mg/dL, n=30, and 2.31±1.56 mg/dL, n=16, respectively, p0.05). Conclusion The mean postoperative CRP levels were highest on post-IPG insertion day 2 and decreased rapidly, returning to the normal range on post-IPG implantation day 6. The duration of post-lead implantation period influenced the magnitude of CRP elevation at post-IPG insertion day 2. Information about the normal response of CRP following DBS could help to avoid unnecessary diagnostic and therapeutic efforts. PMID:26587192

  7. Limit-experience of time in Zoé Valdés's Querido primer novio

    Directory of Open Access Journals (Sweden)

    Olivia Torijano Navarrete

    2013-12-01

    Full Text Available Zoé Valdés, a Cuban writer currently living in exile in France, wrote Dear First Love, a story narrated by multiple narrator-characters, including Time itself. In this book, the time in which the characters and objects exist is transient, however, it is possible to determine the moment of enunciation and in this way discover that the story is a myth created within that fiction. This emerges from the discordancy between actual time and mythical time, a subject much discussed by Paul Ricoeur. The protagonist of the novel travels backin time by means of her memory, while at the same time goes on an actual journey to rescue the beloved of his memories. Such limit-experiences are associated with the axial moment, since without the latter it is not possible to understand the chronological succession of events: one cannot tell what came first or what comes next. Limit-experiences occur when monumental time in the novel coincides with the chronological time of the characters. When trying to explain this situation, it becomes clear that the character develops his orher life and actions at their own pace within their world, and thus time may have a different meaning for each of the characters.

  8. The zircon SHRIMP chronology and trace element geochemistry of the Carboniferous volcanic rocks in western Tianshan Mountains

    Institute of Scientific and Technical Information of China (English)

    ZHU Yongfeng; ZHANG Lifei; GU Libing; GUO Xuan; ZHOU Jing

    2005-01-01

    The genesis of the Carboniferous volcanic rocks in the Dahalajunshan group, mainly consisting of trachytes and trachy-andesites and distributing widely in western Tianshan Mountains, remains to be controversial. It has been proposed to be relevant to "rift" or "plume". Detailed petrology and geochemical data presented in this paper show that these volcanic rocks represent typical continental arc magmatism. The volcanic rocks are mainly trachy-andesitic, and the magma source is enriched in LILE, Th and Pb, and depleted in HFSE and Ce. Trace element geochemical study suggests that the basalts could be modeled by 7%-11% partial melt of garnet lherzolite. The volcanic rocks in the Dahalajunshan group are neither the products of "rift" nor so-called "plume" but represent the continental island arc of the Paleo-Southern Tianshan Ocean. The mantle wedge had been modified by the melt generating in subduction zone during a long evolution history of this island arc. The continental crust materials (i.e. mainly sediment on ocean floor) had been added into island arc through melt in subduction zone. Volcanic rocks occurring in different regions might represent magma eruption in different time. The zircon SHRIMP dating indicates that the ages of the basalt varies between 334.0 Ma and 394.9 Ma. The 13 analyses give an average age of 353.7 (4.5 Ma (MSWD = 1.7). The apparent ages of zircons in trachy-andesite vary between 293.0 Ma and 465.4 Ma. All analyses fall on the U-Pb concordant line and are divided into two groups. 8 analyses produce an average age of 312.8(4.2 Ma (MSWD = 1.7), which represents the crystallizing age of zircon rims in trachy-andesite. The acquired two ages (i.e. 354 and 313 Ma) belong to the Early Carboniferous and Late Carboniferous epochs, respectively. Thus, the Dahalajunshan group would be separated into several groups with the accumulation of high-quality age dating and data of trace element and isotopic geochemistry, in our opinion.

  9. Time outs

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000756.htm Time outs To use the sharing features on this ... children, 2 to 12 years old. Why Does Time out Work? When you put children in time ...

  10. Accurate and homogeneous abundance patterns in solar-type stars of the solar neighbourhood: a chemo-chronological analysis

    Science.gov (United States)

    da Silva, R.; Porto de Mello, G. F.; Milone, A. C.; da Silva, L.; Ribeiro, L. S.; Rocha-Pinto, H. J.

    2012-06-01

    Aims: We report the derivation of abundances of C, Na, Mg, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Y, Zr, Ba, Ce, Nd, and Sm in a sample of 25 solar-type stars of the solar neighbourhood, correlating the abundances with the stellar ages, kinematics, and orbital parameters. Methods: The spectroscopic analysis, based on data of high resolution and high signal-to-noise ratio, was differential to the Sun and applied to atomic line equivalent widths supplemented by the spectral synthesis of C and C2 features. We also performed a statistical study by using the method of tree clustering analysis, searching for groups of stars sharing similar elemental abundance patterns. We derived the stellar parameters from various criteria, with average errors of 30 K, 0.13 dex, and 0.05 dex, respectively, for Teff, log g, and [Fe/H]. The average error of the [X/Fe] abundance ratios is 0.06 dex. Ages were derived from theoretical HR diagrams and membership of the stars in known kinematical moving groups. Results: We identified four stellar groups: one having, on average, over-solar abundances (⟨[X/H]⟩ = +0.26 dex), another with under-solar abundances (⟨ [X/H] ⟩ = -0.24 dex), and two with intermediate values (⟨ [X/H] ⟩ = -0.06 and +0.06 dex) but with distinct chemical patterns. Stars sharing solar metallicity, age, and Galactic orbit possibly have non-solar abundance ratios, a possible effect either of chemical heterogeneity in their natal clouds or migration. A trend of [Cu/Fe] with [Ba/Fe] seems to exist, in agreement with previous claims in the literature, and maybe also of [Sm/Fe] with [Ba/Fe]. No such correlation involving C, Na, Mn, and Zn is observed. The [X/Fe] ratios of various elements show significant correlations with age. [Mg/Fe], [Sc/Fe], and [Ti/Fe] increase with age. [Mn/Fe] and [Cu/Fe] display a more complex behaviour, first increasing towards younger stars up to the solar age, and then decreasing, a result we interpret as possibly related to time

  11. Lateglacial fluvial activity in an upland basin following deglaciation, River Tyne, Northumberland, UK: drivers, complications and chronology

    Science.gov (United States)

    Yorke, L.; Rumsby, B. T.

    2010-12-01

    cut-bank sections and supplemented with British Geological Survey (BGS) borehole data. Dating involved taking optically stimulated luminescence (OSL) samples from carefully selected lithofacies. Results show that terrace surfaces (T1-T4) lie at 8, 10, 15 and 20 m above present river level, with valley floor cut-and-fill sequences lying between 1 and 7 m above the river. The precise timing of incision of the glacigenic valley infill is unclear, but at least 30 m of incision through the infill took place before 11.5 ka, leading to the formation of the two highest terraces, T3 and T4. OSL dates for T1 and T2 indicate that they formed during the early Holocene period (11.4 - 7.9 ka). We show that the quasi-continuous incision trend in the Tyne that has preserved the upper terraces is a consequence of both isostatic rebound, change in sediment delivery and runoff related to climate instability, as well as (probably) a degree of coastal shortening in the early Holocene.

  12. The chronology of the Upper Pleistocene Volcanic Groups of Bad Bertrich and Wartgesberg (Eifel, FRG) - new attempts using luminescence dating

    Science.gov (United States)

    Zoeller, Ludwig; Schmidt, Christoph; Fischer, Manfred; Kolb, Thomas; Schaarschmidt, Maria

    2016-04-01

    The volcanic groups of Bad Bertrich and Wartgesberg are situated in the most southeastern part of the Quaternary West Eifel Volcanic Field (WEVF) and are, therefore, of major interest for understanding origin and timing of the WEVF. For geomorphological reasons the eruptions were placed within the last Glacial. Recent Ar/Ar-dating results suggest ages of 32±11 ka and 31±11 ka, respectively (MERTZ ET AL. 2015). We used xenoliths from Lower Devonian country rock (slates and quarzitic slates) and a maar tephra to explore the feasibility of thermoluminescence (TL) to date the eruptions more accurately. Fine-grained (4-30 μm) quartz was extracted from the samples by grinding and etching in H2SiF6. Because of their high saturation dose the red (620 nm) TL-emissions from quartz was measured using a SAR protocol. Dose-rates were computed based on analytical results from thick source alpha counting (U, Th), ICP-OES (K) and high resolution gamma spectrometry. For the Wartgesberg volcanic group our preliminary results agree with the independent Ar/Ar-ages but can bracket the eruption age to 33±3 ka. Furthermore, the suggestion by RICHTER ET AL. (2015) to avoid quartz extracted from crustal xenoliths having been heated too high is confirmed. For the Bad Bertrich volcanic group our preliminary results are ambiguous. The "Hardtmaar"-Tephra is dated to 27±3 ka in agreement with the age of this group supposed by MERZ ET AL. (2015). Three xenoliths from the nearby "Facher Höhe" scoria cone, however, yielded consistent but significantly lower TL ages. From the view of volcanic stratigraphy there is so far no evidence of a significantly younger eruption phase. From one of these samples we so far found evidence of non-thermal fading as described by RICHTER ET AL. (2015) which needs further investigation. Stimulated by results of PREUSSER ET AL. (2011) we aim at applying also OSL and IRSL dating of the xenoliths and the maar tephra to clarify the age of the "Facher Höhe" scoria

  13. Proximal tephra stratigraphy of the englacial 2004 Grímsvötn eruption, Iceland: event chronology and eruption dynamics

    Science.gov (United States)

    Jude-Eton, Tanya C.; Thordarson, Thorvaldur; Gudmundsson, Magnus T.

    2010-05-01

    Here we present a reconstruction of the 2004 englacial eruptive sequence, based on detailed field and laboratory study of the proximal tephra succession. upon Detailed logging and correlation of 48 vertical sections through the proximal tephra pile shortly after the event. This succession consists of a distinctly bedded sequence, representing at least six separate phases of activity. Detailed logging and correlation of 48 vertical sections through the proximal tephra pile shortly after the event has enabled analysis of the tephra transport and deposition regimes. Relationships throughout the bulk of the tephra succession are consistent with sustained but pulsating activity (Phases 2, 4, and 6), punctuated by intermittent discrete events (Phases 1, 3, and 5). Phase 1 of the eruption comprises a medium to coarse ash, widespread fall layer (25-30cm), and an overlying surge deposit, consisting of cross-bedded fine to medium ash (20-40cm). Both of these units are almost exclusively composed of black poorly-vesicular grains. Phase 2 consists of an up to 5m thick sequence of fine ash to medium lapilli tephra, displaying indistinct discordant cross-bedding, and highlighted by numerous single-grain thick pumice trains. Broken and abraded pumice fragments make up >90% of the lapilli size fraction and the ash-grade matrix is largely composed of shards of disintegrated pumice. Another distinctive feature is numerous pumice lenses that are variably continuous over tens to hundreds of centimetres, with maximum thicknesses of ~30cm. We interpret these to represent the remnants of contemporaneous fall deposits. The observed structures within the units along with their widespread dispersal suggest that they were formed by sustained deposition that lasted for several hours to days at a time. The onset of Phase 3 is marked by bombardment of ballistic blocks (vent clearing) which form decimetre to metre deep impact sags in the surface of the pre-existing tephra pile. This was

  14. 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

  15. {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.

  16. 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

  17. 14C chronology of the oldest Scandinavian church in use. An AMS/PIXE study of lime lump carbonate in the mortar

    Science.gov (United States)

    Lindroos, Alf; Ranta, Heikki; Heinemeier, Jan; Lill, Jan-Olof

    2014-07-01

    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 14C 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 14C 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 14C 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. Comparison of chronological and corrected ages in the gross motor assessment of low-risk preterm infants during the first year of life Comparação das idades cronológica e corrigida na avaliação motora grosseira de lactentes pré-termo com baixo risco no primeiro ano de vida

    OpenAIRE

    Ana Paula Restiffe; José Luiz Dias Gherpelli

    2006-01-01

    OBJECTIVE: To evaluate the need of chronological age correction according to the degree of prematurity, when assessing gross motor development in preterm infants, during the first year of life. METHOD: Cohort, observational and prospective study. Alberta Infant Motor Scale (AIMS) was used to evaluate 43 preterm infants with low risk for motor neurological sequelae, during the first year of corrected age. Mean scores were analyzed according to chronological and corrected ages. Children with mo...

  20. Residence time vs influence time

    OpenAIRE

    E. J. M. Delhez; de Brye, B.; de Brauwere, A.; Deleersnijder, E.

    2014-01-01

    The concepts of age, residence time, exposure time and influence time provide space and time dependent quantitative measures of the rate at which water masses and pollutants enter and/or leave a control domain. To help avoid confusion between these concepts, this paper provides clear definitions of the residence time and the influence time. The similarities and differences between them are illustrated using both a simplified 1D advection-diffusion model and a realistic two-dimensional model o...