Dental and Skeletal Maturity- A Biological Indicator of Chronologic Age

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Saha, Sonali; Yadav, Gunjan; Tripathi, Abhay Mani; Grover, Kavita

2014-01-01

Introduction: Precise evaluation of the developmental stage of a child is not only an integral part of both diagnosis and treatment of paediatric patients; it is also essential in Forensic Medicine and Dentistry. Physiologic age can be estimated by somatic, sexual, skeletal and dental maturity. Aim: Investigate the relationship between the dental age (DA) and skeletal age (SA) of children and comparing it with the chronological age (CA). Materials and Methods: The dental age estimation methods of Schour and Massler (S&M), and Demirjian and Goldstien (D&G) and skeletal assessment methods of Greulich and Pyle (G&P), and Tanner et al., (TW2) were used to analyze the orthopantomograms and hand-wrist radiographs respectively of 150 healthy subjects within the age range of 5-15 y and compared with the Chronological Age. Statistical Analysis: Data collected was statistically analysed using the SPSS version 15.0 Statistical Analysis Software. For all tests p-value of <0.05 were considered statistically significance. Results: Dental age estimation techniques were found comparable and equally reliable as the skeletal age estimation methods. Strong correlations between dental and skeletal maturation were demonstrated. PMID:25386525

Correlation between cervical vertebral maturation and chronological age in a group of Iranian females

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Seyed Mohammadreza Safavi

2015-01-01

Full Text Available Background: Correlation between chronological age at different stages of cervical vertebral maturation (CVM is important in clinical orthodontic practice. The objective of this study was to evaluate the correlation between CVM stage and chronological age in a group of Iranian female patients. Materials and Methods: This study was conducted on 196 digital lateral cephalometry of female patients with the age ranged 9-14 years. The CVM stage was determined with two calibrated examiners, using the method developed by Baccetti and its correlation with mean chronological age was assessed by the Spearman rank-order. The intra and inter-agreements were evaluated by weighted Kappa statistics in overall diagnosis of stages, in addition to determination of presence or absent of concavities at the lower border of second, third and fourth cervical vertebrae and the shapes of the third and fourth vertebrae. P < 0.05 was considered as significant. Results: The correlation coefficient between CVM stages and chronological age was relatively low (r = 0.62. The least amount of inter-observer agreement was determined to be at the clinical decision of the shape of the fourth vertebra. Conclusion: Regarding the low reported correlation, the concomitant usage of other skeletal indicators seems necessary for precise determination of physiological age of the patients.

Correlation between cervical vertebral maturation and chronological age in a group of Iranian females

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Safavi, Seyed Mohammadreza; Beikaii, Hanie; Hassanizadeh, Raheleh; Younessian, Farnaz; Baghban, Alireza Akbarzadeh

2015-01-01

Background: Correlation between chronological age at different stages of cervical vertebral maturation (CVM) is important in clinical orthodontic practice. The objective of this study was to evaluate the correlation between CVM stage and chronological age in a group of Iranian female patients. Materials and Methods: This study was conducted on 196 digital lateral cephalometry of female patients with the age ranged 9-14 years. The CVM stage was determined with two calibrated examiners, using the method developed by Baccetti and its correlation with mean chronological age was assessed by the Spearman rank-order. The intra and inter-agreements were evaluated by weighted Kappa statistics in overall diagnosis of stages, in addition to determination of presence or absent of concavities at the lower border of second, third and fourth cervical vertebrae and the shapes of the third and fourth vertebrae. P < 0.05 was considered as significant. Results: The correlation coefficient between CVM stages and chronological age was relatively low (r = 0.62). The least amount of inter-observer agreement was determined to be at the clinical decision of the shape of the fourth vertebra. Conclusion: Regarding the low reported correlation, the concomitant usage of other skeletal indicators seems necessary for precise determination of physiological age of the patients. PMID:26604958

Correlation between cervical vertebral maturation and chronological age in a group of Iranian females.

Science.gov (United States)

Safavi, Seyed Mohammadreza; Beikaii, Hanie; Hassanizadeh, Raheleh; Younessian, Farnaz; Baghban, Alireza Akbarzadeh

2015-01-01

Correlation between chronological age at different stages of cervical vertebral maturation (CVM) is important in clinical orthodontic practice. The objective of this study was to evaluate the correlation between CVM stage and chronological age in a group of Iranian female patients. This study was conducted on 196 digital lateral cephalometry of female patients with the age ranged 9-14 years. The CVM stage was determined with two calibrated examiners, using the method developed by Baccetti and its correlation with mean chronological age was assessed by the Spearman rank-order. The intra and inter-agreements were evaluated by weighted Kappa statistics in overall diagnosis of stages, in addition to determination of presence or absent of concavities at the lower border of second, third and fourth cervical vertebrae and the shapes of the third and fourth vertebrae. P < 0.05 was considered as significant. The correlation coefficient between CVM stages and chronological age was relatively low (r = 0.62). The least amount of inter-observer agreement was determined to be at the clinical decision of the shape of the fourth vertebra. Regarding the low reported correlation, the concomitant usage of other skeletal indicators seems necessary for precise determination of physiological age of the patients.

Cell-autonomous mechanisms of chronological aging in the yeast Saccharomyces cerevisiae

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Anthony Arlia-Ciommo

2014-05-01

Full Text Available A body of evidence supports the view that the signaling pathways governing cellular aging – as well as mechanisms of their modulation by longevity-extending genetic, dietary and pharmacological interventions - are conserved across species. The scope of this review is to critically analyze recent advances in our understanding of cell-autonomous mechanisms of chronological aging in the budding yeast Saccharomyces cerevisiae. Based on our analysis, we propose a concept of a biomolecular network underlying the chronology of cellular aging in yeast. The concept posits that such network progresses through a series of lifespan checkpoints. At each of these checkpoints, the intracellular concentrations of some key intermediates and products of certain metabolic pathways - as well as the rates of coordinated flow of such metabolites within an intricate network of intercompartmental communications - are monitored by some checkpoint-specific ′′master regulator′′ proteins. The concept envisions that a synergistic action of these master regulator proteins at certain early-life and late-life checkpoints modulates the rates and efficiencies of progression of such processes as cell metabolism, growth, proliferation, stress resistance, macromolecular homeostasis, survival and death. The concept predicts that, by modulating these vital cellular processes throughout lifespan (i.e., prior to an arrest of cell growth and division, and following such arrest, the checkpoint-specific master regulator proteins orchestrate the development and maintenance of a pro- or anti-aging cellular pattern and, thus, define longevity of chronologically aging yeast.

Cell-autonomous mechanisms of chronological aging in the yeast Saccharomyces cerevisiae.

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Arlia-Ciommo, Anthony; Leonov, Anna; Piano, Amanda; Svistkova, Veronika; Titorenko, Vladimir I

2014-05-27

A body of evidence supports the view that the signaling pathways governing cellular aging - as well as mechanisms of their modulation by longevity-extending genetic, dietary and pharmacological interventions - are conserved across species. The scope of this review is to critically analyze recent advances in our understanding of cell-autonomous mechanisms of chronological aging in the budding yeast Saccharomyces cerevisiae . Based on our analysis, we propose a concept of a biomolecular network underlying the chronology of cellular aging in yeast. The concept posits that such network progresses through a series of lifespan checkpoints. At each of these checkpoints, the intracellular concentrations of some key intermediates and products of certain metabolic pathways - as well as the rates of coordinated flow of such metabolites within an intricate network of intercompartmental communications - are monitored by some checkpoint-specific "master regulator" proteins. The concept envisions that a synergistic action of these master regulator proteins at certain early-life and late-life checkpoints modulates the rates and efficiencies of progression of such processes as cell metabolism, growth, proliferation, stress resistance, macromolecular homeostasis, survival and death. The concept predicts that, by modulating these vital cellular processes throughout lifespan (i.e., prior to an arrest of cell growth and division, and following such arrest), the checkpoint-specific master regulator proteins orchestrate the development and maintenance of a pro- or anti-aging cellular pattern and, thus, define longevity of chronologically aging yeast.

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

DEFF Research Database (Denmark)

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

2013-01-01

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

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

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

2000-01-01

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

Evaluation of third molar development and its relation to chronological age: a panoramic radiographic study.

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Zandi, Mohammad; Shokri, Abbas; Malekzadeh, Hamid; Amini, Payam; Shafiey, Parastu

2015-06-01

Third molar development, in comparison to other teeth in the dentition, has the greatest variation in morphology, anatomical position, and time of development and eruption, and its reliability for chronological age estimation is controversial. The aim of the present study was to evaluate third molar development and its relation to chronological age using panoramic radiography. A total of 2536 digital panoramic radiographs of individuals aged between 5 and 26 years were selected. The developmental status of the third molars was assessed using eight-stage developmental scoring proposed by Demirjian et al., with one modification: a stage 0 was added. The collected data were entered into a checklist and subjected to statistical analyses. The mean ages of the first appearance of third molar bud, complete crown formation, and root apex closure were around 9, 14, and 22 years, respectively. In both jaws, third molar development occurred symmetrically, and sexual dimorphism was observed at some developmental stages. Finally, two formulas were presented to estimate age of the juveniles and adolescents based on their gender and developmental stages of the third molars, and validated on a second sample consisting of 523 individuals aged between 8 and 22. Assessment of third molar development was found to be a reliable method for age estimation of individuals between 11 and 22 years. Because of possible ethnic and geographic differences in third molar development, population specific researches were recommended.

Effect of chronological age of beef steers of different maturity types ...

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Effect of chronological age of beef steers of different maturity types on their growth ... and carcass studies have been conducted in the sourveld regions of the country. ... different beef maturity types which differ in body frame size were used, viz.

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

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

2006-01-01

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

What about time? Examining chronological and subjective age and their relation to work motivation

NARCIS (Netherlands)

Akkermans, J.; Lange, A.H. de; Heijden, B.I.J.M. van der; Kooij, D.T.A.M.; Jansen, P.G.W.; Dikkers, J.S.E.

2016-01-01

PURPOSE - The aging workforce is becoming an increasingly important topic in today’s labor market. However, most scientific research and organizational policies focus on chronological age as the main determinant of successful aging. Based on life span developmental theories – primarily

Nicotinamide supplementation phenocopies SIR2 inactivation by modulating carbon metabolism and respiration during yeast chronological aging.

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Orlandi, Ivan; Pellegrino Coppola, Damiano; Strippoli, Maurizio; Ronzulli, Rossella; Vai, Marina

2017-01-01

Nicotinamide (NAM), a form of vitamin B 3 , is a byproduct and noncompetitive inhibitor of the deacetylation reaction catalyzed by Sirtuins. These represent a family of evolutionarily conserved NAD + -dependent deacetylases that are well-known critical regulators of metabolism and aging and whose founding member is Sir2 of Saccharomyces cerevisiae. Here, we investigated the effects of NAM supplementation in the context of yeast chronological aging, the established model for studying aging of postmitotic quiescent mammalian cells. Our data show that NAM supplementation at the diauxic shift results in a phenocopy of chronologically aging sir2Δ cells. In fact, NAM-supplemented cells display the same chronological lifespan extension both in expired medium and extreme Calorie Restriction. Furthermore, NAM allows the cells to push their metabolism toward the same outcomes of sir2Δ cells by elevating the level of the acetylated Pck1. Both these cells have the same metabolic changes that concern not only anabolic pathways such as an increased gluconeogenesis but also respiratory activity in terms both of respiratory rate and state of respiration. In particular, they have a higher respiratory reserve capacity and a lower non-phosphorylating respiration that in concert with a low burden of superoxide anions can affect positively chronological aging. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

What about time? : Examining chronological and subjective age and their relation to work motivation.

NARCIS (Netherlands)

Akkermans,; De Lange,; Van der Heijden,; Kooij, T.A.M.; Jansen,; Dikkers,

2016-01-01

Purpose The aging workforce is becoming an increasingly important topic in today’s labor market. However, most scientific research and organizational policies focus on chronological age as the main determinant of successful aging. Based on life span developmental theories – primarily socioemotional

What about Time? Examining Chronological and Subjective Age and their Relation to Work Motivation

NARCIS (Netherlands)

Akkermans, J.; de Lange, A.H.; Van der Heijden, B.I.J.M.; Kooij, T.A.M.; Jansen, P.G.W.; Dikkers, J.

2016-01-01

Purpose: The aging workforce is becoming an increasingly important topic in today’s labor market. However, most scientific research and organizational policies focus on chronological age as the main determinant of successful aging. Based on life span developmental theories – primarily socioemotional

Revision of the Martian relative age chronology

International Nuclear Information System (INIS)

Barlow, N.G.

1987-01-01

This study has provided a more detailed chronology than currently exists in the literature and has created some changes to the currently accepted geological evolutionary sequence of Mars. The period of heavy bombardment, although dominated by impact processes, experienced many forms of volcanic activity and at least one episode of intense fracturing. Most small volcanic constructs and the ridged plains regions are found to date from this early period, contrary to common belief. The fracturing and dissection of the highlands helps to provide further constraints on the timing of events such as the formation of the hemispheric dichotomy and the formation of the Tharsis Bulge. The northern plains are found to consist of a number of differently aged regions. The difference in age between the chaotic terrain and the outflow channels together with differences in the distribution curves among craters of various erosional states found on the channels support the theory of episodic periods of flooding

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

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Litsas, George; Lucchese, Alessandra

2016-01-01

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. 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. Chronological and dental age showed a high correlation for both gender(r =0.741 for boys, r = 0.770 for girls, pStage IV for both males (r=0.554) and females (r=0.68). The lowest correlation was for the CVM Stage III in males (r=0.433, pStage II in females (r=0.393, p>0.001). The t-test revealed statistically significant differences between these variables (pstages was determined. The second molars showed the highest correlation with CVM stages (CVMS) (r= 0.65 for boys, r = 0.72 for girls). 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.

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

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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.

Subjective physical and cognitive age among community-dwelling older people aged 75 years and older: differences with chronological age and its associated factors.

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Ihira, Hikaru; Furuna, Taketo; Mizumoto, Atsushi; Makino, Keitaro; Saitoh, Shigeyuki; Ohnishi, Hirofumi; Shimada, Hiroyuki; Makizako, Hyuma

2015-01-01

The aim of this cross-sectional study was to determine the associations between self-reported subjective physical and cognitive age, and actual physical and cognitive functions among community-dwelling older people aged 75 years and older. The sample comprised 275 older adults aged 75-91 years. Two questions were asked regarding subjective age: 'How old do you feel physically?' and 'How old do you feel cognitively?' To assess physical functions, we measured handgrip strength, knee extension strength, standing balance and walking speed. Tests of attention, executive function, processing speed and memory were performed to assess actual cognitive function. Subjective physical and cognitive age was associated with performance on all of the physical and cognitive tests, respectively (p older adults who reported themselves as feeling older than their chronological age had a slower walking speed and lower scores for word-list memory recall than those who did not report themselves as feeling older than their actual age. These findings suggest that promoting a fast walking speed and good memory function may help to maintain a younger subjective physical and cognitive age in older adults aged 75 years and older.

Assessment of skeletal age using MP3 and hand-wrist radiographs and its correlation with dental and chronological ages in children.

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Bala, M; Pathak, A; Jain, R L

2010-01-01

The purpose of the study was to assess skeletal age using MP3 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 (MP3) and hand-wrist of the right hand and intra oral periapical X-ray for right permanent maxillary canine. Skeletal age was assessed from MP3 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 MP3 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.

Correlation between chronological age and third molar developmental stages in an Iranian population (Demirjian method).

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Khosronejad, Aria; Navabi, Manijeh; Sakhdari, Shirin; Rakhshan, Vahid

2017-01-01

Third molar development is the only available tool for estimating the age of individuals after puberty. Since this tooth has very high interethnic variability, formulas calculated to estimate the age from its development stages cannot be generalized to other populations and should be adjusted for each region. Therefore, this study was conducted to evaluate this method in a sample of Tehran individuals for the first time, and also to compare the development of third molars across sexes and arches, and to estimate cutoff developmental stages for legal minor/major identification. A total of 150 dental patients aged between 15 and 25 years old were prospectively enrolled, and their Demirjian stages were recorded. The associations between chronological age and Demirjian stages were evaluated. Dental formation was compared between sexes and jaws. Cutoff stages were determined to identify legal minor/major cases (above or below 18 years old). Age estimation formula was found for this population. Of the 150 included patients, 56 were males. The difference between the ages of males and females at each given developmental stage was nonsignificant ( P > 0.05), except for the H stage. Age difference between same stage teeth of the maxilla and mandible was nonsignificant. Each of the G and H stages was significantly above 18 years old ( P age were above 90% (all P Third molar development was positively affected by the chronological age ( P = 0.000) and being maxillary ( P = 0.000) but not sex ( P = 0.113). Regression formula for age estimation was: age = 6.52+ (0.64 × sex) + (0.32 × arch) + (1.86 × Demirjian stage). Development of third molar might complete after the age 22. Iranian individuals with third molars at the G and H stages are likely above 18 while those at E and F are likely below 18. Pace of molar development differs for jaws, but intergender differences are open to further investigations.

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

International Nuclear Information System (INIS)

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

1987-01-01

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

Correlación entre las edades cronológica y ósea en pacientes de ortodoncia Correlation between the chronological and bone ages in orthodontics patients

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Gladia Toledo Mayarí

2011-03-01

Full Text Available Nos propusimos determinar la edad ósea según sexo y edad cronológica e identificar la relación existente entre las edades cronológica y ósea, en los pacientes estudiados. Se realizó un estudio descriptivo y transversal en un universo constituido por todos los niños y adolescentes tributarios de tratamiento ortodóncico, que ingresaron en la Clínica de Ortodoncia de la Facultad de Estomatología de la Universidad de Ciencias Médicas de La Habana, en el periodo de enero de 2004 a diciembre de 2006. El grupo etáreo se encontraba entre 8 y 16 años, de donde se seleccionó una muestra de 150 pacientes, mediante un muestreo por cuotas. A cada paciente se le realizó una radiografía de la mano izquierda, donde se determinó la edad ósea, a través del método de Tanner-Whitehouse 2 (TW2 y se calculó la correlación entre la edad ósea y la cronológica a través del coeficiente de correlación lineal de Pearson. Se encontraron correlaciones altas muy significativas entre las edades cronológica y ósea, en ambos sexos; sexo femenino r= 0,977 y masculino r= 0,983 (pTo determine the bone age according to the sex and chronologic age and to identify the relation between the chronologic and bone ages in study patients. A cross-sectional and descriptive study was conducted in a universe including all children and adolescents needing orthodontics treatment admitted in the Orthodontics Clinic of the Stomatology Faculty of the Higher Institute of Medical Sciences (HIMS-Habana from January, 2004 to December, 2006 aged between 8 and 16 selecting a sample including 150 patients by admission sampling, each patient undergoes a left hand radiography to determine the bone age by Tanner-Whitehouse 2 method (TW2 estimating the correlation between the bone age and chronologic one trough Pearson linear correlation coefficient. There were high and very significant correlations between the bone ages and the chronologic one in both sexes, female sex r= 0

Staging of third molar development in relation to chronological age of 5-16 year old Indian children.

Science.gov (United States)

Hegde, Sapna; Patodia, Akash; Dixit, Uma

2016-12-01

The usefulness of the developmental status of the third molar has been studied in assessment of the chronological age of adolescents in whom the development of the other permanent teeth is nearly complete. However, little is known about the timing and pattern of third-molar development in the Indian population. This study aimed to stage the third molar development in relation to chronological age of 5-16year old Indian children. In this cross-sectional observational study, the status of third molar development in relation to chronological age of 1139 Indian children aged 5-16 years was evaluated radiographically, using Orhan's modification of Demirjian's method. The frequency of occurrence of the third molars varied from 47% to 70%. Crypt formation, crown completion and root completion occurred as early as 5.4, 8.7 and 15.0 years, respectively. No significant differences based on gender or side were observed in third-molar development (p>0.05). For most stages, maxillary third molars were slightly more advanced than their mandibular counterparts (p>0.05). Considering the high degree of variability observed in third molar genesis and development, the usefulness of this tooth in age determination studies may be very limited in the age group studied. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Radiographic assessment of third molars development and it's relation to dental and chronological age in an Iranian population.

Science.gov (United States)

Monirifard, Mohamad; Yaraghi, Navid; Vali, Ava; Vali, Asana; Vali, Amrita

2015-01-01

The aim of the present study was to estimate chronological age based on third molar development and to determine the association between dental age and third molar calcification stages. In this cross-sectional study, 505 digital panoramic radiographs of 223 males (44.2%) and 282 females (55.8%) between the age of 6 and 17 were selected from patients who were treated in Departments of Pediatrics and Orthodontics of Isfahan University of Medical Sciences between the years of 2009 and 2013. Correlation between chronological age and third molar development was analyzed with SPSS 21 using Spearman's Rank correlation coefficient, Chi-square test and multiple regression statistical tests (P third molars demonstrated a highly significant correlation with dental age (P age were mandibular left third molar in males and mandibular right third molar in females (r s = 0.072). When multiple regression was used to predict dental age based on molar calcification stage, the only significant correlation was between maxillary left third molar in males (P third molars in females. Relationship between chronological age and molars development stage was significant in all age subgroups and in both gender (P third molars and dental age in males. Results showed that third molar calcification stage can be used as an age predictor and in general mandibular teeth seems to be more reliable for this purpose in both genders and in all ages.

Radiocarbon measurements on submerged forest floating chronologies

International Nuclear Information System (INIS)

Campbell, J.A.; Baxter, M.S.

1979-01-01

It is stated that the submerged forests along the west coast of England and Wales provide a unique source of wood for radiocarbon/ dendrochronological studies. 14 C age determinations are reported on sequential growth increments from three 'gloating' chronologies. A sampling frequency of approximately 10 samples per century was used. Fluctuations in atmospheric 14 C levels of 2 to 3% over several decades can occur, these variations being superimposed on a smoothly changing trend. (author)

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

Science.gov (United States)

Tuteja, Monica; Bahirwani, Shraddha; Balaji, P

2012-01-01

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. 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. Predicted minimum age and mean age of the study sample were found to be significant predictors (Page. 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. 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.

An in vivo study on brain microstructure in biological and chronological ageing

DEFF Research Database (Denmark)

Altmann-Schneider, Irmhild; de Craen, Anton J M; van den Berg-Huysmans, Annette A

2015-01-01

phenotype of familial longevity. Moreover, we aimed to describe cerebral ageing effects on MTI parameters in an elderly cohort. All subjects were included from the Leiden Longevity Study and underwent 3 Tesla MTI of the brain. In total, 183 offspring of nonagenarian siblings, who are enriched for familial...... factors of longevity, were contrasted with 163 environmentally and age-matched controls. No differences in cortical and subcortical gray matter and white matter MTI parameters were found between offspring and control subjects using histogram-based and voxel-wise analyses. Cortical gray matter and white...... matter MTI parameters decreased with increasing chronological age (all p

Overview of the frontal sinus anteroposterior size based on against lateral cephalometric radiographs chronological age as forensic identification

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Georgiana Marsya

2017-08-01

Full Text Available Introduction: One part of the most important individual identification procedure is approximate age can be done on an individual living or dead. Judging from some of the methods that have been there, have not found a method forecasts age through the frontal sinuses, particularly research conducted in Indonesia. The frontal sinus can be used for identification because the frontal sinuses began to evolve and look at radiographs at the age of 7 years and did not change after the age of 20 years, it reveals the existence of differences in the size of the frontal sinuses with age. The onbjectives of this study was to asses of the frontal sinus anteroposterior size based on against lateral cephalometric radiographs chronological age as forensic identification. Methods: A number of samples are 502 lateral cephalometric patient data from secondary data of patients aged 7-20 years, 335 pieces of lateral cephalometric Purpose of study is to asses of the frontal sinus anteroposterior size chronological age as forensic identification. radiograph female patients and 167 pieces in male patients. Data anteroposterior size of the frontal sinus is obtained by pulling the longest line perpendicular to the line of Sh-Sl. Results: the results showed that at the age of 7 years the average size of the frontal sinus anteroposterior 4.20 mm and 5.05 mm which is the smallest size, while the average size of the biggest, by 8.46 mm in women and men at the age of 11.37 mm 20 years. Conclusions: In women, the fastest increase occurred at the age of 7-8 years, males at the age of 16-18 years. The frontal sinuses anteroposterior size increases with age, both men, and women.

Precise chronologies of Holocene glacial culminations in the Cordillera Vilcabamba of southern Peru

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Licciardi, J. M.; Schaefer, J. M.; Schweinsberg, A. D.

2012-12-01

Records of past fluctuations in climatically sensitive tropical mountain glaciers are among the best indicators of regional paleoclimatic trends and controls. The majority of the world's present-day tropical glaciers are found in the Peruvian Andes, but accurate and precise chronologies of past glacial activity in this region remain relatively scarce, particularly during the Holocene. Here we present ~50 new 10Be exposure ages derived from boulders on well-preserved moraine successions in several glaciated drainages in the Cordillera Vilcabamba of southern Peru (13°20'S latitude). The new results suggest that prominent moraines in these valleys are correlative with previously published moraine ages near Nevado Salcantay in this range (Licciardi et al., 2009), but also expand on the initial surface exposure chronologies to reveal additional periods of glacier stabilization not found in previous work. A provisional composite chronology that merges the new and previously obtained moraine ages indicates at least five discrete glacial culminations from the Lateglacial to the late Holocene. Forthcoming 10Be ages from an additional ~50 samples collected from moraine boulders will increase the precision and completeness of the Vilcabamba moraine chronologies. Basal radiocarbon ages are being developed from bog and lake sediments in stratigraphic contact with the 10Be-dated moraines. These new 14C age data will help constrain the local cosmogenic 10Be production rate, thereby increasing the accuracy of the 10Be chronologies.

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

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

2013-10-10

To study the chronological age of third-molar mineralisation of Turkish children from the southwest Eastern Anatolia region, the Demirjian staging method was used to determine the stage of the mineralisation of four third molars (18, 28, 38 and 48) and to compare third-molar development by sex and age with the results of previous studies. The study comprised 832 Turkish children from the southwest Eastern Anatolia region aged 6-16 years based on radiological evidence from digital orthopantomograms. The mean age of the 832 patients was 11.03±1.98 years, with 424 males (mean age, 10.97±1.97) and 408 females (mean age, 11.09±2.00). The orthopantomograms were scored by two observers. The Wilcoxon matched-pairs signed-rank test used to assess intra- and inter-observer assessment revealed strong agreement between both observers' measurements. Statistical analysis of the association between sex and age was performed with the Mann-Whitney U-test and the Wilcoxon test. Regression analysis was performed to obtain regression formulae for calculating the dental and the chronological age. The statistical analysis showed a strong correlation between age and third-molar development in males (R(2)=0.61) and females (R(2)=0.63). New equations (age=7.49+0.69, development stage (DS) 38+0.70, DS18) were derived for estimation of the chronological age. The results showed that there was no significant difference in mineralisation between 18 and 28 and 38 and 48 in males or females. For both sexes, the dental age was lower than the chronological age. Males reached the developmental stages earlier than females. In the whole population, the boys' and the girls' dental ages were 0.84 years and 0.16 years earlier, respectively, than their chronological ages. The use of third-molar teeth as a developmental marker is suitable, particularly when comparing the obtained standard deviation with other skeletal-age calculation techniques. Copyright © 2013 Elsevier Ireland Ltd. All rights

Measuring Biological Age via Metabonomics: The Metabolic Age Score.

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Hertel, Johannes; Friedrich, Nele; Wittfeld, Katharina; Pietzner, Maik; Budde, Kathrin; Van der Auwera, Sandra; Lohmann, Tobias; Teumer, Alexander; Völzke, Henry; Nauck, Matthias; Grabe, Hans Jörgen

2016-02-05

Chronological age is one of the most important risk factors for adverse clinical outcome. Still, two individuals at the same chronological age could have different biological aging states, leading to different individual risk profiles. Capturing this individual variance could constitute an even more powerful predictor enhancing prediction in age-related morbidity. Applying a nonlinear regression technique, we constructed a metabonomic measurement for biological age, the metabolic age score, based on urine data measured via (1)H NMR spectroscopy. We validated the score in two large independent population-based samples by revealing its significant associations with chronological age and age-related clinical phenotypes as well as its independent predictive value for survival over approximately 13 years of follow-up. Furthermore, the metabolic age score was prognostic for weight loss in a sample of individuals who underwent bariatric surgery. We conclude that the metabolic age score is an informative measurement of biological age with possible applications in personalized medicine.

A 481-year chronology of oak earlywood vessels as an age-independent climatic proxy in NW Iberia

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Souto-Herrero, Manuel; Rozas, Vicente; García-González, Ignacio

2017-08-01

The earlywood vessels of ring-porous trees can be analyzed dendrochronologically and used as a proxy for environmental information. However, most works deal with the analysis of contemporary climate-growth relationships and do not evaluate their long-term variation. We obtained a 481-year chronology of earlywood vessel size of oak (Quercus robur L.) in the northwestern Iberian Peninsula, investigated its behavior through time, and compared it to a chronology of younger trees developed at the same site. We expressed earlywood vessel size as the hydraulically-weighted diameter (DH) and discriminated between vessels in the first row (r1) and the rest of the vessels (nr1); radial increment was assessed from latewood width (LW). Climate-growth relationships were strong and nearly identical for both age classes. Spring temperature positively affected vessel size, but only for the first row, probably mediating the onset of cambial activity. The chronology of old trees showed an almost flat age trend, except for the first decades, and series were not affected by stand dynamics. In contrast, LW had a weak response to climate, probably because of the high impact of abrupt growth changes. There was a high negative correlation between DH and the winter North Atlantic Oscillation Index (NAO), which was unstable during the 20th century. To our knowledge, this is the longest chronology of earlywood vessel size obtained to date, and offers promising results, as this proxy is shown to be independent of age and forest disturbances, and was strongly correlated to climate across long time spans.

Nuclear cosmo-chronology

International Nuclear Information System (INIS)

Berkes, I.

2002-01-01

Nuclear cosmo-chronology is based on the age determination method by using pairs of isotopes or elements: 235 U / 238 U, 187 Re / 187 Os 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.)

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

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

2014-05-01

The purpose of the study was to estimate the chronology of third molar mineralization in Han population of southwestern China and find its unique characteristics so that it would provide a reference in several legal cases like forensic age estimation. The study used Demirjian's staging method to study 2192 orthopantomograms of 984 male and 1208 female subjects aged between 8 and 25 years. The statistical data was analyzed by Student's t test and ANOVA. The conclusions of the study are: (1) The chronological mineralization age of third molars of Han population in Southwestern China is similar to the Turkish and the Japanese, was earlier than the Austrian and Han of South China, but later than the Spanish. (2) The mineralization timing of the third molars between two sides in maxilla or mandible has no significant differences in the same gender group. (3) There is no significant difference in mineralization of third molars between male and female, except for tooth 48 in Demirjian's stage E. (4) The mineralization of third molar in maxilla is earlier than mandible. Copyright © 2014 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

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

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

2015-11-01

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

Chronologic and actinically induced aging in human facial skin

International Nuclear Information System (INIS)

Gilchrest, B.A.; Szabo, G.; Flynn, E.; Goldwyn, R.M.

1983-01-01

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

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

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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...

An optical age chronology of late Quaternary extreme fluvial events recorded in Ugandan dambo soils

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Mahan, S.A.; Brown, D.J.

2007-01-01

There is little geochonological data on sedimentation in dambos (seasonally saturated, channel-less valley floors) found throughout Central and Southern Africa. Radiocarbon dating is problematic for dambos due to (i) oxidation of organic materials during dry seasons; and (ii) the potential for contemporary biological contamination of near-surface sediments. However, for luminescence dating the equatorial site and semi-arid climate facilitate grain bleaching, while the gentle terrain ensures shallow water columns, low turbidity, and relatively long surface exposures for transported grains prior to deposition and burial. For this study, we focused on dating sandy strata (indicative of high-energy fluvial events) at various positions and depths within a second-order dambo in central Uganda. Blue-light quartz optically stimulated luminescences (OSL) ages were compared with infrared stimulated luminescence (IRSL) and thermoluminescence (TL) ages from finer grains in the same sample. A total of 8 samples were dated, with 6 intervals obtained at ???35, 33, 16, 10.4, 8.4, and 5.9 ka. In general, luminescence ages were stratigraphically, geomorphically and ordinally consistent and most blue-light OSL ages could be correlated with well-dated climatic events registered either in Greenland ice cores or Lake Victoria sediments. Based upon OSL age correlations, we theorize that extreme fluvial dambo events occur primarily during relatively wet periods, often preceding humid-to-arid transitions. The optical ages reported in this study provide the first detailed chronology of dambo sedimentation, and we anticipate that further dambo work could provide a wealth of information on the paleohydrology of Central and Southern Africa. ?? 2006 Elsevier Ltd. All rights reserved.

Northern Chinese dental ages estimated from southern Chinese reference datasets closely correlate with chronological age

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Hai Ming Wong

2016-12-01

Full Text Available While northern and southern Chinese are genetically correlated, there exists notable environmental differences in their living conditions. This study aimed to evaluate validity of the southern Chinese reference dataset for dental age estimation applied to northern Chinese. Dental panoramic tomographs of 437 northern Chinese aged 3 to 21 years were analysed. All the left maxillary and mandibular permanent teeth plus the 2 third molars on the right side were scored based on Demirjian’s classification of tooth development stages. Mean and standard error of dental age were obtained for each tooth development stage, followed by random effect meta-analysis for mean dental age estimation. Validity of the method was examined through measures of agreement (95% limits of agreement, standard error of measurement, and Lin’s concordance correlation coefficient and measure of reliability (Intraclass correlation coefficient. On average, the estimated dental age overestimated chronological age by only around 1 month in both females and males. The Intraclass correlation coefficient values were 0.99 for both sexes, suggesting excellent reliability of the method. Reference dataset for dental age estimation developed on the basis of southern Chinese was applicable for use among the northern Chinese.

10Be exposure age chronology of the last glaciation of the Roháčská Valley in the Western Tatra Mountains, central Europe

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Engel, Zbyněk; Mentlík, Pavel; Braucher, Régis; Křížek, Marek; Pluháčková, Markéta; Arnold, Maurice; Aumaître, Georges; Bourlès, Didier; Keddadouche, Karim; Aster Team; Arnold, Maurice; Aumaître, Georges; Bourlès, Didier; Keddadouche, Karim

2017-09-01

10Be exposure ages from moraines and bedrock sites in the Roháčská Valley provide chronology of the last glaciation in the largest valley of the Western Tatra Mts., the Western Carpathians. The minimum apparent exposure age of 19.4 ± 2.1 ka obtained for the oldest sampled boulder and the mean age of 18.0 ± 0.8 ka calculated for the terminal moraine indicate that the oldest preserved moraine was probably deposited at the time of the global Last Glacial Maximum (LGM). The age of this moraine coincides with the termination of the maximum glacier expansion in other central European ranges, including the adjacent High Tatra Mts. and the Alps. The equilibrium line altitude (ELA) of the LGM glacier in the Roháčská Valley, estimated at 1400-1410 m a.s.l., was 50-80 m lower than in the eastern part of the range, indicating a positive ELA gradient from west to east among the north-facing glaciers in the Tatra Mts. Lateglacial glacier expansion occurred no later than 13.4 ± 0.5 ka and 11.9 ± 0.5 ka, as indicated by the mean exposure ages calculated for re-advance moraines. This timing is consistent with the exposure age chronology of the last Lateglacial re-advance in the High Tatra Mts., Alps and lower mountain ranges in central Europe. The ELA in the Roháčská Valley estimated at 1690-1770 m a.s.l. in this period was located 130-300 m lower than in the north-facing valleys in the High Tatra Mts. 10Be exposure ages obtained for a rock glacier constrains the timing of this landform stabilization in the Salatínska Valley and provides the first chronological evidence for the Lateglacial activity of rock glaciers in the Carpathians.

A comparison of the validity of the Demirjian, Willems, Nolla and Häävikko methods in determination of chronological age of 5-15 year-old Indian children.

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Hegde, Sapna; Patodia, Akash; Dixit, Uma

2017-08-01

Demirjian's method has been the most popular and extensively tested radiographic method of age estimation. More recently, Willems' method has been reported to be a better predictor of age. Nolla's and Häävikko's methods have been used to a lesser extent. Very few studies have compared all four methods in non-Indian and Indian populations. Most Indian research is limited by inadequate sample sizes, age structures and grouping and different approaches to statistical analysis. The present study aimed to evaluate and compare the validity of the Demirjian, Willems, Nolla and Häävikko methods in determination of chronological age of 5 to 15 year-old Indian children. In this cross-sectional observational study, four methods were compared for validity in estimating the age of 1200 Indian children aged 5-15 years. Demirjian's method overestimated age by +0.24 ± 0.80, +0.11 ± 0.81 and +0.19 ± 0.80 years in boys, girls and the total sample, respectively. With Willems' method, overestimations of +0.09 ± 0.80, +0.08 ± 0.80 and +0.09 ± 0.80 years were obtained in boys, girls and the total sample, respectively. Nolla's method underestimated age by -0.13 ± 0.80, -0.30 ± 0.82 and -0.20 ± 0.81 years in boys, girls and the total sample, respectively. Häävikko's method underestimated age by -0.17 ± 0.80, -0.29 ± 0.83 and -0.22 ± 0.82 years in boys, girls and the total sample, respectively. Statistically significant differences were observed between dental and chronological ages with all methods (p age, followed by Demirjian's, Nolla's and Häävikko's methods. All four methods could be applicable for estimating age in the present population, mean prediction errors being lower than 0.30 years (3.6 months). Copyright © 2017 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Chronological Age as Factor Influencing the Dental Implant Osseointegration in the Jaw Bone

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Jan Papež

2018-04-01

Full Text Available The objectives of this study were to evaluate osseointegration of dental implant in the jaw bone in the young and elderly population and comparing the results to assess indicators and risk factors as age for the success or failure of dental implants. A retrospective study of 107 implants (Impladent, LASAK, Czech Republic was prepared. The patients at implants surgery were divided in three groups. The patients were followed-up for a 7-year period. We evaluated osseointegration from long term point of view as a change of marginal bone levels close to dental implant. Marginal bone levels were recorded and analysed with regard to different patient- and implant-related factors. An influence of chronological age on change of marginal bone levels during 6-year retrospective study vas evaluated. The study examined 47 patient charts and 107 implants from the Second Faculty of Medicine, Charles University and University Hospital Motol. We proved that young healthy patients with long bridges or Branemarks have the same progression of marginal bone levels changes. The chronological age hasn’t therefore direct influence on the osseointegration from long term point of view. But we found that the length of dental suprastrucure-prosthetic construction negatively influences marginal bone changes, though these results weren’t statistically significant. More extensive dental implant suprastrucure undergoes smaller osseointegration. On the other hand the length of dental suprastrucure (prosthetic construction negatively influences dental osseointegration in both groups of patient.

Do the age differences given by relative or absolute chronologies of the most ancient meteorites correspond to real age differences

International Nuclear Information System (INIS)

Pellas, P.

1982-01-01

Recent results from absolute and relative chronologies of the most ancient meteorites are reviewed in order to analyze if they are significant or not. Use of the various chronometers to analyze the same meteoritic sample is shown to be an interesting approach to retrace the prehistory of meteorites and their environments. (orig.)

A comparison of cervical vertebral maturation assessment of skeletal growth stages with chronological age in Thai between cleft lip and palate and non-cleft patients.

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Pisek, Poonsak; Godfrey, Keith; Manosudprasit, Montian; Wangsrimongkol, Tasanee; Leelasinjaroen, Pornnapha

2013-09-01

(1) To search for any difference in chronological age related to stages of the cervical vertebral maturation index stages (CVMIs) comparing groups of cleft lip and palate (CLP) and non-cleft (non-CLP) subjects; (2) To investigate the relationship between chronological age and CVMIs in both groups of subjects. Cervical vertebrae C2, C3, C4 were assessed on 1,549 cephalometric films (503 CLP films, 1,046 non-CLP films of subjects aged 5 to 18 years) using Hassel and Farman's method. T-tests showed mean chronological ages of CVMIs 2, 3 and 6 were different at p = 0.001, 0.024 and 0.016, respectively. CVMIs 1, 4 and 5 showed no significant differences. The CLP group achieved each CVMI score one year ahead of the non-CLP group, except for CVMI 4. Spearman's rank order correlations were r = 0.80 (95% CI: 0.76-0.83) for CLP, and 0.77 (95% CI: 0.74-0.79) for non-CLP. CLP subjects tended to have a slightly advanced growth compared with non-CLP subjects. A high correlation coefficient was found between chronological age and cervical vertebral skeletal maturation.

Chronology of the Acheulean to Middle Stone Age transition in eastern Africa

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Deino, Alan L.; Behrensmeyer, Anna K.; Brooks, Alison S.; Yellen, John E.; Sharp, Warren D.; Potts, Richard

2018-04-01

The origin of the Middle Stone Age (MSA) marks the transition from a highly persistent mode of stone toolmaking, the Acheulean, to a period of increasing technological innovation and cultural indicators associated with the evolution of Homo sapiens. We used argon-40/argon-39 and uranium-series dating to calibrate the chronology of Acheulean and early MSA artifact–rich sedimentary deposits in the Olorgesailie basin, southern Kenya rift. We determined the age of late Acheulean tool assemblages from 615,000 to 499,000 years ago, after which a large technological and faunal transition occurred, with a definitive MSA lacking Acheulean elements beginning most likely by ~320,000 years ago, but at least by 305,000 years ago. These results establish the oldest repository of MSA artifacts in eastern Africa.

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

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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.…

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.

A matter of months: High precision migration chronology of a Bronze Age female.

Directory of Open Access Journals (Sweden)

Karin Margarita Frei

Full Text Available Establishing the age at which prehistoric individuals move away from their childhood residential location holds crucial information about the socio dynamics and mobility patterns in ancient societies. We present a novel combination of strontium isotope analyses performed on the over 3000 year old "Skrydstrup Woman" from Denmark, for whom we compiled a highly detailed month-scale model of her migration timeline. When combined with physical anthropological analyses this timeline can be related to the chronological age at which the residential location changed. We conducted a series of high-resolution strontium isotope analyses of hard and soft human tissues and combined these with anthropological investigations including CT-scanning and 3D visualizations. The Skrydstrup Woman lived during a pan-European period characterized by technical innovation and great social transformations stimulated by long-distance connections; consequently she represents an important part of both Danish and European prehistory. Our multidisciplinary study involves complementary biochemical, biomolecular and microscopy analyses of her scalp hair. Our results reveal that the Skrydstrup Woman was between 17-18 years old when she died, and that she moved from her place of origin -outside present day Denmark- to the Skrydstrup area in Denmark 47 to 42 months before she died. Hence, she was between 13 to 14 years old when she migrated to and resided in the area around Skrydstrup for the rest of her life. From an archaeological standpoint, this one-time and one-way movement of an elite female during the possible "age of marriageability" might suggest that she migrated with the aim of establishing an alliance between chiefdoms. Consequently, this detailed multidisciplinary investigation provides a novel tool to reconstruct high resolution chronology of individual mobility with the perspective of studying complex patterns of social and economic interaction in prehistory.

A matter of months: High precision migration chronology of a Bronze Age female

Science.gov (United States)

Villa, Chiara; Jørkov, Marie Louise; Allentoft, Morten E.; Kaul, Flemming; Ethelberg, Per; Reiter, Samantha S.; Wilson, Andrew S.; Taube, Michelle; Olsen, Jesper; Lynnerup, Niels; Willerslev, Eske; Kristiansen, Kristian; Frei, Robert

2017-01-01

Establishing the age at which prehistoric individuals move away from their childhood residential location holds crucial information about the socio dynamics and mobility patterns in ancient societies. We present a novel combination of strontium isotope analyses performed on the over 3000 year old “Skrydstrup Woman” from Denmark, for whom we compiled a highly detailed month-scale model of her migration timeline. When combined with physical anthropological analyses this timeline can be related to the chronological age at which the residential location changed. We conducted a series of high-resolution strontium isotope analyses of hard and soft human tissues and combined these with anthropological investigations including CT-scanning and 3D visualizations. The Skrydstrup Woman lived during a pan-European period characterized by technical innovation and great social transformations stimulated by long-distance connections; consequently she represents an important part of both Danish and European prehistory. Our multidisciplinary study involves complementary biochemical, biomolecular and microscopy analyses of her scalp hair. Our results reveal that the Skrydstrup Woman was between 17–18 years old when she died, and that she moved from her place of origin -outside present day Denmark- to the Skrydstrup area in Denmark 47 to 42 months before she died. Hence, she was between 13 to 14 years old when she migrated to and resided in the area around Skrydstrup for the rest of her life. From an archaeological standpoint, this one-time and one-way movement of an elite female during the possible “age of marriageability” might suggest that she migrated with the aim of establishing an alliance between chiefdoms. Consequently, this detailed multidisciplinary investigation provides a novel tool to reconstruct high resolution chronology of individual mobility with the perspective of studying complex patterns of social and economic interaction in prehistory. PMID:28582402

Differences between biological and chronological age-at-death in human skeletal remains: A change of perspective.

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Couoh, Lourdes R

2017-08-01

This analysis seeks to determine whether differences between real and estimated chronological age (CA) with biological age (BA) in skeletal individuals reflect variability in aging. A total of 87 individuals of two samples, ranging from 20 to 94 years old, were analyzed. One, partially documented, belongs to a Mexican skeletal collection dating to the 20th century; the other is an assemblage of prehispanic individuals from different archaeological sites. In all specimens, the tooth annulation method (TCA) was applied to estimate CA, while-excluding individuals older than 80 years-auricular surface (AS) and pubic symphysis (PS) methods were used to estimate BA. Statistical analyses were conducted to identify correlations and significance of the differences between CA vs. TCA, CA vs. AS/PS, TCA vs. AS/PS. Sex of individuals was assessed for its influence in aging. The use of TCA to estimate CA was successful for most individuals. A strong correlation was found between CA vs. TCA, CA vs. AS/PS, TCA vs. AS/PS and their differences were significant but variation in these were found when assessed by separate age groups. Sex did not influence such differences. TCA can be used to estimate CA and its differences with BA, being less than 10 years, are similar to those found in living populations. Differences between CA and BA are due to intra-population variability, which could be the consequence of individual differences in aging. More research is needed to have confidence that under- and overestimations of BA are indicators of aging variability at the level of the individual. © 2017 Wiley Periodicals, Inc.

Relative chronology of Martian volcanoes

International Nuclear Information System (INIS)

Landheim, R.; Barlow, N.G.

1991-01-01

Impact cratering is one of the major geological processes that has affected the Martian surface throughout the planet's history. The frequency of craters within particular size ranges provides information about the formation ages and obliterative episodes of Martian geologic units. The Barlow chronology was extended by measuring small craters on the volcanoes and a number of standard terrain units. Inclusions of smaller craters in units previously analyzed by Barlow allowed for a more direct comparison between the size-frequency distribution data for volcanoes and established chronology. During this study, 11,486 craters were mapped and identified in the 1.5 to 8 km diameter range in selected regions of Mars. The results are summarized in this three page report and give a more precise estimate of the relative chronology of the Martian volcanoes. Also, the results of this study lend further support to the increasing evidence that volcanism has been a dominant geologic force throughout Martian history

Ethanol and Acetate Acting as Carbon/Energy Sources Negatively Affect Yeast Chronological Aging

Directory of Open Access Journals (Sweden)

Ivan Orlandi

2013-01-01

Full Text Available In Saccharomyces cerevisiae, the chronological lifespan (CLS is defined as the length of time that a population of nondividing cells can survive in stationary phase. In this phase, cells remain metabolically active, albeit at reduced levels, and responsive to environmental signals, thus simulating the postmitotic quiescent state of mammalian cells. Many studies on the main nutrient signaling pathways have uncovered the strong influence of growth conditions, including the composition of culture media, on CLS. In this context, two byproducts of yeast glucose fermentation, ethanol and acetic acid, have been proposed as extrinsic proaging factors. Here, we report that ethanol and acetic acid, at physiological levels released in the exhausted medium, both contribute to chronological aging. Moreover, this combined proaging effect is not due to a toxic environment created by their presence but is mainly mediated by the metabolic pathways required for their utilization as carbon/energy sources. In addition, measurements of key enzymatic activities of the glyoxylate cycle and gluconeogenesis, together with respiration assays performed in extreme calorie restriction, point to a long-term quiescent program favoured by glyoxylate/gluconeogenesis flux contrary to a proaging one based on the oxidative metabolism of ethanol/acetate via TCA and mitochondrial respiration.

Chronology of the Acheulean to Middle Stone Age transition in eastern Africa.

Science.gov (United States)

Deino, Alan L; Behrensmeyer, Anna K; Brooks, Alison S; Yellen, John E; Sharp, Warren D; Potts, Richard

2018-04-06

The origin of the Middle Stone Age (MSA) marks the transition from a highly persistent mode of stone toolmaking, the Acheulean, to a period of increasing technological innovation and cultural indicators associated with the evolution of Homo sapiens We used argon-40/argon-39 and uranium-series dating to calibrate the chronology of Acheulean and early MSA artifact-rich sedimentary deposits in the Olorgesailie basin, southern Kenya rift. We determined the age of late Acheulean tool assemblages from 615,000 to 499,000 years ago, after which a large technological and faunal transition occurred, with a definitive MSA lacking Acheulean elements beginning most likely by ~320,000 years ago, but at least by 305,000 years ago. These results establish the oldest repository of MSA artifacts in eastern Africa. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

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

International Nuclear Information System (INIS)

Choi, Joon-Seok; Lee, Cheol-Koo

2013-01-01

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

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.

Reassessment of the Upper Fremont Glacier ice-core chronologies by synchronizing of ice-core-water isotopes to a nearby tree-ring chronology

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Chellman, Nathan J.; McConnell, Joseph R.; Arienzo, Monica; Pederson, Gregory T.; Aarons, Sarah; Csank, Adam

2017-01-01

The Upper Fremont Glacier (UFG), Wyoming, is one of the few continental glaciers in the contiguous United States known to preserve environmental and climate records spanning recent centuries. A pair of ice cores taken from UFG have been studied extensively to document changes in climate and industrial pollution (most notably, mid-19th century increases in mercury pollution). Fundamental to these studies is the chronology used to map ice-core depth to age. Here, we present a revised chronology for the UFG ice cores based on new measurements and using a novel dating approach of synchronizing continuous water isotope measurements to a nearby tree-ring chronology. While consistent with the few unambiguous age controls underpinning the previous UFG chronologies, the new interpretation suggests a very different time scale for the UFG cores with changes of up to 80 years. Mercury increases previously associated with the mid-19th century Gold Rush now coincide with early-20th century industrial emissions, aligning the UFG record with other North American mercury records from ice and lake sediment cores. Additionally, new UFG records of industrial pollutants parallel changes documented in ice cores from southern Greenland, further validating the new UFG chronologies while documenting the extent of late 19th and early 20th century pollution in remote North America.

Cerebral blood flow and oximetry response to blood transfusion in relation to chronological age in preterm infants.

Science.gov (United States)

Banerjee, J; Leung, T S; Aladangady, N

2016-06-01

Preterm infants frequently receive blood transfusion (BT) and the aim of this study was to measure the effect of BT on cerebral blood flow and oxygenation in preterm infants in relation to chronological age. Preterm infants undergoing intensive care recruited to three chronological age groups: 1 to 7 (Group 1; n=20), 8 to 28 (Group 2; n=21) & ≥29days of life (Group 3; n=18). Pre and post-BT anterior cerebral artery (ACA) time averaged mean velocity (TAMV) and superior vena cava (SVC) flow were measured. Cerebral Tissue Haemoglobin Index (cTHI) and Oxygenation Index (cTOI) were measured from 15-20min before to 15-20min post-BT using NIRS. Vital parameters and blood pressure were measured continuously. Mean BP increased significantly, and there was no significant change in vital parameters following BT. Pre-BT ACA TAMV was higher in Group 2 and 3 compared to Group 1 (pBlood transfusion increased cTOI and cTHI and decreased ACA TAMV in all groups. PDA had no impact on the baseline cerebral oximetry and blood flow as well as changes following blood transfusion. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

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

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…

Quantifying bamboo coral growth rate nonlinearity with the radiocarbon bomb spike: A new model for paleoceanographic chronology development

Science.gov (United States)

Frenkel, M. M.; LaVigne, M.; Miller, H. R.; Hill, T. M.; McNichol, A.; Gaylord, M. Lardie

2017-07-01

Bamboo corals, long-lived cold water gorgonin octocorals, offer unique paleoceanographic archives of the intermediate ocean. These Isididae corals are characterized by alternating gorgonin nodes and high Mg-calcite internodes, which synchronously extend radially. Bamboo coral calcite internodes have been utilized to obtain geochemical proxy data, however, growth rate uncertainty has made it difficult to construct precise chronologies for these corals. Previous studies have relied upon a single tie point from records of the anthropogenic Δ14C bomb spike preserved in the gorgonin nodes of live-collected corals to calculate a mean radial extension rate for the outer 50 years of skeletal growth. Bamboo coral chronologies are typically constructed by applying this mean extension rate to the entire coral record, assuming constant radial extension with coral age. In this study, we aim to test this underlying assumption by analyzing the organic nodes of six California margin bamboo corals at high enough resolution (bomb spike, including two tie points at 1957 and 1970, plus the coral collection date (2007.5) for four samples. Radial extension rates between tie points ranged from 10 to 204 μm/year, with a decrease in growth rate evident between the 1957-1970 and 1970-2007.5 periods for all four corals. A negative correlation between growth rate and coral radius (r =-0.7; p=0.04) was determined for multiple bamboo coral taxa and individuals from the California margin, demonstrating a decline in radial extension rate with specimen age and size. To provide a mechanistic basis for these observations, a simple mathematical model was developed based on the assumption of a constant increase in circular cross sectional area with time to quantify this decline in radial extension rate with coral size between chronological tie points. Applying the area-based model to our Δ14C bomb spike time series from individual corals improves chronology accuracy for all live-collected corals

Double the dates and go for Bayes - Impacts of model choice, dating density and quality on chronologies

Science.gov (United States)

Blaauw, Maarten; Christen, J. Andrés; Bennett, K. D.; Reimer, Paula J.

2018-05-01

Reliable chronologies are essential for most Quaternary studies, but little is known about how age-depth model choice, as well as dating density and quality, affect the precision and accuracy of chronologies. A meta-analysis suggests that most existing late-Quaternary studies contain fewer than one date per millennium, and provide millennial-scale precision at best. We use existing and simulated sediment cores to estimate what dating density and quality are required to obtain accurate chronologies at a desired precision. For many sites, a doubling in dating density would significantly improve chronologies and thus their value for reconstructing and interpreting past environmental changes. Commonly used classical age-depth models stop becoming more precise after a minimum dating density is reached, but the precision of Bayesian age-depth models which take advantage of chronological ordering continues to improve with more dates. Our simulations show that classical age-depth models severely underestimate uncertainty and are inaccurate at low dating densities, and also perform poorly at high dating densities. On the other hand, Bayesian age-depth models provide more realistic precision estimates, including at low to average dating densities, and are much more robust against dating scatter and outliers. Indeed, Bayesian age-depth models outperform classical ones at all tested dating densities, qualities and time-scales. We recommend that chronologies should be produced using Bayesian age-depth models taking into account chronological ordering and based on a minimum of 2 dates per millennium.

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 differences emerged across the diagnostic groups on a variety of fears. Children with ASD were reported to have more situation phobias and medical fears, but fewer fears of harm/injury compared to all other groups. The groups also differed in terms of the pattern of correlations between fears, phobias, anxieties and behavior problems. For children with ASD, fears, phobias and anxieties were closely related to problem behaviors, whereas fears, phobias, and anxieties were less related to behavioral symptoms for the other groups of subjects. Such findings suggest that children with ASD exhibit a distinct profile of fear and anxiety compared to other mental age and chronologically age-matched children, and these fears are related to the symptoms associated with ASD.

Appearance and chronology of Textile ceramics in the Middle and Upper Volga region: critical comparison of conventional 14C-, AMS- and typological chronologies

Directory of Open Access Journals (Sweden)

Lavento Mika T.

2015-06-01

Full Text Available The article offers a comparison of three different methods of chronology construction – conventional 14C (radiocarbon dating, AMS (accelerator mass-spectrometry dating and the so called typological chronology – to date the textile ceramics of the Bronze – Early Iron Age in the Northern Coniferous Zone of Europe, from the Upper and Middle Volga and Kama Rivers to the Baltic region and Scandinavia. The Textile Ceramics Culture (also known as “Net”, “Pseudo-textile”, “Spun-and-speckled” is often associated with a Finnish-speaking community from the Bronze – beginning of the Iron Age. The earliest date of the Textile Ceramics sites on the Middle Oka River is presumably considered to be the 18 th century BC. Datings of the reference sites in the Middle Volga region were fixed within the 15 th – 8 th centuries BC. Comparing these data with the AMS chronology available for the materials from Finland and Estonia, the authors conclude that appearance of the Textile Ceramics was almost synchronous in the Volga and the Baltic regions, although chronology of the early tradition of the Textile Ceramics seems to be different in these areas. The results of yet a small number of AMS dates should be treated only as preliminary. However, AMS-dating seems to be the most efficient tool for further refining of the Textile Ceramics chronology over a vast territory, including in the Volga region.

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

Science.gov (United States)

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

2011-01-01

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

Chronology and stratigraphy of the Magdalen Islands archipelago from the last glaciation to the early Holocene: new insights into the glacial and sea-level history of eastern Canada

DEFF Research Database (Denmark)

Rémillard, Audrey M.; St-Onge, Guillaume; Bernatchez, Pascal

2016-01-01

of the deposits and the establishment of a precise chronological framework. This study provides a detailed description of 21 stratigraphical sequences located throughout the archipelago, as well as the first comprehensive luminescence chronology from the Last Glacial Maximum (LGM) to c. 10 ka. In addition......The Magdalen Islands (Québec, Canada) are a key location for unravelling the glacial and sea-level history of the Maritime Provinces of eastern Canada. Although many sedimentary sequences have been described in the literature, absolute ages are lacking, impeding an accurate interpretation...... to the five samples collected for age control purposes, 34 luminescence samples were taken from 17 different sites in glacial, periglacial and coastal deposits. The stratigraphical and chronological data reveal that the islands were at the crossroads of two icecaps during the LGM; the southern islands were...

The Moderating Effect of Chronological Age on the Relation Between Neuroticism and Physical Functioning: Cross-Sectional Evidence From Two French Samples.

Science.gov (United States)

Canada, Brice; Stephan, Yannick; Jaconelli, Alban; Duberstein, Paul R

2016-01-01

Prior studies of age-restricted samples have demonstrated that, in older adulthood, neuroticism is negatively associated with difficulties performing specific daily activities. No studies of neuroticism and physical functioning have been conducted on life-span samples. This study tested the hypothesis that the relationship between neuroticism and physical functioning is stronger in older people compared with younger and middle-aged adults. Data were obtained from 2 independent French samples (n = 1,132 and 1,661 for Samples 1 and 2, respectively) ranging in age from 18 to 97. In addition to reporting sociodemographics, participants completed the Big Five Inventory, the physical functioning scale of the 36-Item Short Form Health Survey, and measures of disease burden. In both samples, regression analysis indicated that neuroticism is more negatively associated with physical functioning with advancing age, controlling for gender, marital status, disease burden, and educational attainment. In life-span samples of more than 2,700 adults, neuroticism was more strongly associated with worse physical functioning among older people compared with younger and middle-aged adults. Longitudinal research is needed to confirm this finding and to identify potential mediators. © The Author 2014. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Toward unified ice core chronologies with the DatIce tool

Science.gov (United States)

Toye Mahamadou Kele, H.; Lemieux-Dudon, B.; Blayo, E.

2012-04-01

Antarctic and Greenland ice cores provide a means to study the phase relationships of climate changes in both hemispheres. They also enable to study the timing between climate, and greenhouse gases or orbital forcings. One key step for such studies is to improve the absolute and relative precisions of ice core age scales (for ice and trapped gas), and beyond that, to try to reach the best consistency between chronologies of paleo records of any kind. The DatIce tool is designed to increase the consistency between pre-existing (also called background) core chronologies. It formulates a variational inverse problem which aims at correcting three key quantities that uniquely define the core age scales: the accumulation rate, the total thinning function, and the close-off depth. For that purpose, it integrates paleo data constraints of many types among which age markers (with for instance documented volcanoes eruptions), and stratigraphic links (with for instance abrupt changes in methane concentration). A cost function is built that enables to calculate new chronologies by making a trade-off between all the constraints (background chronologies and paleo data). The method presented in Lemieux-Dudon et al (2010) has already been applied simultaneously to EPICA EDML and EDC, Vostok and NGRIP. Currently, on going works are conducted at LSCE Saclay and LGGE Grenoble laboratories to construct unified Antarctic chronologies by applying the DatIce tool with new ice cores and new sets of paleo measurements. We here present the DatIce tool, the underlying methodology, and its potential applications. We further show some improvements that have been made recently. We especially adress the issue related to the calibration of the error of pre-existing core chronologies. They are inputs that may have a strong impact on the results. However these uncertainties are uneasy to analyze, since prior chronologies are most of the time assessed on the basis of glaciological models (firn

Comprehensive Analysis of Large Sets of Age-Related Physiological Indicators Reveals Rapid Aging around the Age of 55 Years.

Science.gov (United States)

Lixie, Erin; Edgeworth, Jameson; Shamir, Lior

2015-01-01

While many studies show a correlation between chronological age and physiological indicators, the nature of this correlation is not fully understood. To perform a comprehensive analysis of the correlation between chronological age and age-related physiological indicators. Physiological aging scores were deduced using principal component analysis from a large dataset of 1,227 variables measured in a cohort of 4,796 human subjects, and the correlation between the physiological aging scores and chronological age was assessed. Physiological age does not progress linearly or exponentially with chronological age: a more rapid physiological change is observed around the age of 55 years, followed by a mild decline until around the age of 70 years. These findings provide evidence that the progression of physiological age is not linear with that of chronological age, and that periods of mild change in physiological age are separated by periods of more rapid aging. © 2015 S. Karger AG, Basel.

Transcriptome States Reflect Imaging of Aging States.

Science.gov (United States)

Eckley, D Mark; Coletta, Christopher E; Orlov, Nikita V; Wilson, Mark A; Iser, Wendy; Bastian, Paul; Lehrmann, Elin; Zhang, Yonqing; Becker, Kevin G; Goldberg, Ilya G

2018-06-14

In this study, we describe a morphological biomarker that detects multiple discrete subpopulations (or "age-states") at several chronological ages in a population of nematodes (Caenorhabditis elegans). We determined the frequencies of three healthy adult states and the timing of the transitions between them across the lifespan. We used short-lived and long-lived strains to confirm the general applicability of the state classifier and to monitor state progression. This exploration revealed healthy and unhealthy states, the former being favored in long-lived strains and the latter showing delayed onset. Short-lived strains rapidly transitioned through the putative healthy state. We previously found that age-matched animals in different age-states have distinct transcriptome profiles. We isolated animals at the beginning and end of each identified state and performed microarray analysis (principal component analysis, relative sample to sample distance measurements, and gene set enrichment analysis). In some comparisons, chronologically identical individuals were farther apart than morphologically identical individuals isolated on different days. The age-state biomarker allowed assessment of aging in a novel manner, complementary to chronological age progression. We found hsp70 and some small heat shock protein genes are expressed later in adulthood, consistent with the proteostasis collapse model.

Third molar mineralization in relation to chronologic age estimation of the Han in central southern China.

Science.gov (United States)

Liu, Ying; Geng, Kun; Chu, Yanhao; Xu, Mindi; Zha, Lagabaiyila

2018-03-03

The purpose of this study is to provide a forensic reference data about estimating chronologic age by evaluating the third molar mineralization of Han in central southern China. The mineralization degree of third molars was assessed by Demirjian's classification with modification for 2519 digital orthopantomograms (1190 males, 1329 females; age 8-23 years). The mean ages of the initial mineralization and the crown completion of third molars were around 9.66 and 13.88 years old in males and 9.52 and 14.09 years old in females. The minimum ages of apical closure were around 16 years in both sexes. Twenty-eight at stage C and stage G and 38 and 48 at stage F occurred earlier in males than in females. There was no significant difference between maxillary and mandibular teeth in males and females except that stage C in males. Two formulas were devised to estimate age based on mineralization stages and sexes. In Hunan Province, the person will probably be over age 14, when a third molar reaches the stage G. The results of the study could provide reference for age estimation in forensic cases and clinical dentistry.

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

International Nuclear Information System (INIS)

Yonenobu, Hitoshi; Hattori, Yoshiaki; Kikata, Yoji; Mitsutani, Takumi; Nakamura, Toshio.

1990-01-01

We measured 14 C/ 13 C Ratio of the Teak. The 14 C 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 14 C concentration in the tropospheric air changes dramatically. And we measured 14 C-chronologies of the annual rings of O-Hinoki, 14 C-chronologies agree well with dendrochronologies for the past 600 years. And the 14 C chronologies support more determinative cross-dating of the archaeological samples. (author)

Middle and Later Stone Age chronology of Kisese II rockshelter (UNESCO World Heritage Kondoa Rock-Art Sites), Tanzania.

Science.gov (United States)

Tryon, Christian A; Lewis, Jason E; Ranhorn, Kathryn L; Kwekason, Amandus; Alex, Bridget; Laird, Myra F; Marean, Curtis W; Niespolo, Elizabeth; Nivens, Joelle; Mabulla, Audax Z P

2018-01-01

The archaeology of East Africa during the last ~65,000 years plays a central role in debates about the origins and dispersal of modern humans, Homo sapiens. Despite the historical importance of the region to these discussions, reliable chronologies for the nature, tempo, and timing of human behavioral changes seen among Middle Stone Age (MSA) and Later Stone Age (LSA) archaeological assemblages are sparse. The Kisese II rockshelter in the Kondoa region of Tanzania, originally excavated in 1956, preserves a ≥ 6-m-thick archaeological succession that spans the MSA/LSA transition, with lithic artifacts such as Levallois and bladelet cores and backed microliths, the recurrent use of red ochre, and >5,000 ostrich eggshell beads and bead fragments. Twenty-nine radiocarbon dates on ostrich eggshell carbonate make Kisese II one of the most robust chronological sequences for understanding archaeological change over the last ~47,000 years in East Africa. In particular, ostrich eggshell beads and backed microliths appear by 46-42 ka cal BP and occur throughout overlying Late Pleistocene and Holocene strata. Changes in lithic technology suggest an MSA/LSA transition that began 39-34.3 ka, with typical LSA technologies in place by the Last Glacial Maximum. The timing of these changes demonstrates the time-transgressive nature of behavioral innovations often linked to the origins of modern humans, even within a single region of Africa.

Chronology of early lunar crust

International Nuclear Information System (INIS)

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

Quantity of dates trumps quality of dates for dense Bayesian radiocarbon sediment chronologies - Gas ion source 14C dating instructed by simultaneous Bayesian accumulation rate modeling

Science.gov (United States)

Rosenheim, B. E.; Firesinger, D.; Roberts, M. L.; Burton, J. R.; Khan, N.; Moyer, R. P.

2016-12-01

Radiocarbon (14C) sediment core chronologies benefit from a high density of dates, even when precision of individual dates is sacrificed. This is demonstrated by a combined approach of rapid 14C analysis of CO2 gas generated from carbonates and organic material coupled with Bayesian statistical modeling. Analysis of 14C is facilitated by the gas ion source on the Continuous Flow Accelerator Mass Spectrometry (CFAMS) system at the Woods Hole Oceanographic Institution's National Ocean Sciences Accelerator Mass Spectrometry facility. This instrument is capable of producing a 14C determination of +/- 100 14C y precision every 4-5 minutes, with limited sample handling (dissolution of carbonates and/or combustion of organic carbon in evacuated containers). Rapid analysis allows over-preparation of samples to include replicates at each depth and/or comparison of different sample types at particular depths in a sediment or peat core. Analysis priority is given to depths that have the least chronologic precision as determined by Bayesian modeling of the chronology of calibrated ages. Use of such a statistical approach to determine the order in which samples are run ensures that the chronology constantly improves so long as material is available for the analysis of chronologic weak points. Ultimately, accuracy of the chronology is determined by the material that is actually being dated, and our combined approach allows testing of different constituents of the organic carbon pool and the carbonate minerals within a core. We will present preliminary results from a deep-sea sediment core abundant in deep-sea foraminifera as well as coastal wetland peat cores to demonstrate statistical improvements in sediment- and peat-core chronologies obtained by increasing the quantity and decreasing the quality of individual dates.

OxCal: versatile tool for developing paleoearthquake chronologies--a primer

Science.gov (United States)

Lienkaemper, J.J.; Ramsey, C.B.

2009-01-01

Ages of paleoearthquakes (events), i.e., evidence of earthquakes inferred from the geologic record, provide a critical constraint on estimation of the seismic hazard posed by an active fault. The radiocarbon calibration program OxCal (4.0.3 and above; Bronk Ramsey 2007, 2001) provides paleoseismologists with a straightforward but rigorous means of estimating these event ages and their uncertainties. Although initially developed for the chronologic modeling of archaeological data from diverse sources (e.g., radiocarbon, historical knowledge, etc.), OxCal is readily adaptable to other disciplines requiring chronological modeling, such as paleoseismology (Fumal et al. 2002; Lindvall et al. 2002; Kelson et al. 2006; Noriega et al. 2006; Lienkaemper and Williams 2007; Yen et al. 2008).

Improvement of skin condition by oral administration of collagen hydrolysates in chronologically aged mice.

Science.gov (United States)

Wang, Zhenbin; Wang, Qing; Wang, Lin; Xu, Weidong; He, Yuanqing; Li, Yunliang; He, Song; Ma, Haile

2017-07-01

Collagen hydrolysates (CHs) have been demonstrated to have positive effects on skin photoaging by topical application or oral ingestion. However, there has been little research on their influence on skin chronological aging. In this study, 9-month-old female ICR mice were given normal AIN-93M diets containing CHs (2.5, 5 and 10% w/w) from Nile tilapia scale. After 6 months, the collagen content and antioxidant enzyme (superoxide dismutase and glutathione peroxidase) activities increased significantly (P skin did not change (P > 0.05). The color, luster and quantity of hair were obviously ameliorated. Moreover, the structure of epidermis and dermis, the density and distribution of collagen fibers and the ratio of type I to type III collagen were improved in a dose-dependent manner as shown by histochemical staining. Oral ingestion of CHs increased the collagen content and antioxidant enzyme activities and improved the appearance and structure of skin. These results suggest the potential of CHs as an anti-skin-aging ingredient in nutraceuticals or functional foods. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Validity of the Demirjian method for dental age estimation for ...

African Journals Online (AJOL)

2015-02-04

Feb 4, 2015 ... Dental age was calculated using the Demirjian's method. Chronologic age was .... in order to avoid the examiner bias at the time of collecting data. ... age using the. Demirjian method for different age groups and total sample.

Paleotempestological chronology developed from gas ion source AMS analysis of carbonates determined through real-time Bayesian statistical approach

Science.gov (United States)

Wallace, D. J.; Rosenheim, B. E.; Roberts, M. L.; Burton, J. R.; Donnelly, J. P.; Woodruff, J. D.

2014-12-01

Is a small quantity of high-precision ages more robust than a higher quantity of lower-precision ages for sediment core chronologies? AMS Radiocarbon ages have been available to researchers for several decades now, and precision of the technique has continued to improve. Analysis and time cost is high, though, and projects are often limited in terms of the number of dates that can be used to develop a chronology. The Gas Ion Source at the National Ocean Sciences Accelerator Mass Spectrometry Facility (NOSAMS), while providing lower-precision (uncertainty of order 100 14C y for a sample), is significantly less expensive and far less time consuming than conventional age dating and offers the unique opportunity for large amounts of ages. Here we couple two approaches, one analytical and one statistical, to investigate the utility of an age model comprised of these lower-precision ages for paleotempestology. We use a gas ion source interfaced to a gas-bench type device to generate radiocarbon dates approximately every 5 minutes while determining the order of sample analysis using the published Bayesian accumulation histories for deposits (Bacon). During two day-long sessions, several dates were obtained from carbonate shells in living position in a sediment core comprised of sapropel gel from Mangrove Lake, Bermuda. Samples were prepared where large shells were available, and the order of analysis was determined by the depth with the highest uncertainty according to Bacon. We present the results of these analyses as well as a prognosis for a future where such age models can be constructed from many dates that are quickly obtained relative to conventional radiocarbon dates. This technique currently is limited to carbonates, but development of a system for organic material dating is underway. We will demonstrate the extent to which sacrificing some analytical precision in favor of more dates improves age models.

Middle and Later Stone Age chronology of Kisese II rockshelter (UNESCO World Heritage Kondoa Rock-Art Sites), Tanzania

Science.gov (United States)

Ranhorn, Kathryn L.; Kwekason, Amandus; Alex, Bridget; Laird, Myra F.; Marean, Curtis W.; Niespolo, Elizabeth; Nivens, Joelle; Mabulla, Audax Z. P.

2018-01-01

The archaeology of East Africa during the last ~65,000 years plays a central role in debates about the origins and dispersal of modern humans, Homo sapiens. Despite the historical importance of the region to these discussions, reliable chronologies for the nature, tempo, and timing of human behavioral changes seen among Middle Stone Age (MSA) and Later Stone Age (LSA) archaeological assemblages are sparse. The Kisese II rockshelter in the Kondoa region of Tanzania, originally excavated in 1956, preserves a ≥ 6-m-thick archaeological succession that spans the MSA/LSA transition, with lithic artifacts such as Levallois and bladelet cores and backed microliths, the recurrent use of red ochre, and >5,000 ostrich eggshell beads and bead fragments. Twenty-nine radiocarbon dates on ostrich eggshell carbonate make Kisese II one of the most robust chronological sequences for understanding archaeological change over the last ~47,000 years in East Africa. In particular, ostrich eggshell beads and backed microliths appear by 46–42 ka cal BP and occur throughout overlying Late Pleistocene and Holocene strata. Changes in lithic technology suggest an MSA/LSA transition that began 39–34.3 ka, with typical LSA technologies in place by the Last Glacial Maximum. The timing of these changes demonstrates the time-transgressive nature of behavioral innovations often linked to the origins of modern humans, even within a single region of Africa. PMID:29489827

Assessing the chronology of bedrock landslides in the Oregon Coastal Range using visible near-infrared spectroscopy

Science.gov (United States)

Mathabane, N.; Cerovski-Darriau, C.; Sweeney, K. E.; Roering, J. J.

2013-12-01

Obtaining accurate chronological data for landslides is critical to understanding their causes as well as their dynamics. The ability to easily and inexpensively date various parts of a landslide can provide insight not only into the 'When' of landslides but also on the 'How' and 'Why' as well. In this study, we apply visible near-infrared (VisNIR) spectroscopy as a means to date landslide soils in a setting with uniform climate and bedrock lithology. In our Oregon Coast Range site, as sandstone-derived soils weather over time, pedogenic hematite accumulates and alters the color of the soil at a quantifiable and discernable rate. This rate having already been established through a soil chronosequence study, we can use the redness of a soil as a proxy for soil age. This is a potentially economical dating method as it does not rely on expensive radioisotopes and requires only a small amount of sample to process. We collected 39 B-horizon soil samples from 7 different slides and used VisNIR spectroscopy to identify the soil residence time of the landslides. The majority of the samples possessed ages between 75,000 and 150,000 years of age, though several slides registered ages over 200,000 years. The average percent error associated with the landslide ages was ~30-35%, although this value was lower for younger slides (200,000 years). Younger slides were more homogenous in age while older slides exhibited more variability. Additionally, there was lower variability in auger-collected samples when compared to samples collected from road-cuts. Our results suggest that VisNIR spectroscopy may prove a more useful dating method on younger, less disturbed landslides but fail to truly capture the age of older, more complicated slides due to its reliance on a specific pedogentic model for hematite weathering as well as the increased risk for complex slide history. This method could be useful in a regional characterization of landslide chronology for similar biomes and provide

Chemical genetic screen identifies lithocholic acid as an anti-aging compound that extends yeast chronological life span in a TOR-independent manner, by modulating housekeeping longevity assurance processes.

Science.gov (United States)

Goldberg, Alexander A; Richard, Vincent R; Kyryakov, Pavlo; Bourque, Simon D; Beach, Adam; Burstein, Michelle T; Glebov, Anastasia; Koupaki, Olivia; Boukh-Viner, Tatiana; Gregg, Christopher; Juneau, Mylène; English, Ann M; Thomas, David Y; Titorenko, Vladimir I

2010-07-01

In chronologically aging yeast, longevity can be extended by administering a caloric restriction (CR) diet or some small molecules. These life-extending interventions target the adaptable target of rapamycin (TOR) and cAMP/protein kinase A (cAMP/PKA) signaling pathways that are under the stringent control of calorie availability. We designed a chemical genetic screen for small molecules that increase the chronological life span of yeast under CR by targeting lipid metabolism and modulating housekeeping longevity pathways that regulate longevity irrespective of the number of available calories. Our screen identifies lithocholic acid (LCA) as one of such molecules. We reveal two mechanisms underlying the life-extending effect of LCA in chronologically aging yeast. One mechanism operates in a calorie availability-independent fashion and involves the LCA-governed modulation of housekeeping longevity assurance pathways that do not overlap with the adaptable TOR and cAMP/PKA pathways. The other mechanism extends yeast longevity under non-CR conditions and consists in LCA-driven unmasking of the previously unknown anti-aging potential of PKA. We provide evidence that LCA modulates housekeeping longevity assurance pathways by suppressing lipid-induced necrosis, attenuating mitochondrial fragmentation, altering oxidation-reduction processes in mitochondria, enhancing resistance to oxidative and thermal stresses, suppressing mitochondria-controlled apoptosis, and enhancing stability of nuclear and mitochondrial DNA.

Retrieving chronological age from dental remains of early fossil hominins to reconstruct human growth in the past.

Science.gov (United States)

Dean, M Christopher

2010-10-27

A chronology of dental development in Pan troglodytes is arguably the best available model with which to compare and contrast reconstructed dental chronologies of the earliest fossil hominins. Establishing a time scale for growth is a requirement for being able to make further comparative observations about timing and rate during both dento-skeletal growth and brain growth. The absolute timing of anterior tooth crown and root formation appears not to reflect the period of somatic growth. In contrast, the molar dentition best reflects changes to the total growth period. Earlier initiation of molar mineralization, shorter crown formation times, less root length formed at gingival emergence into functional occlusion are cumulatively expressed as earlier ages at molar eruption. Things that are similar in modern humans and Pan, such as the total length of time taken to form individual teeth, raise expectations that these would also have been the same in fossil hominins. The best evidence there is from the youngest fossil hominin specimens suggests a close resemblance to the model for Pan but also hints that Gorilla may be a better developmental model for some. A mosaic of great ape-like features currently best describes the timing of early hominin dental development.

Oral histories: a simple method of assigning chronological age to isotopic values from human dentine collagen.

Science.gov (United States)

Beaumont, Julia; Montgomery, Janet

2015-01-01

Stable isotope ratios of carbon (δ(13)C) and nitrogen (δ(15)N) in bone and dentine collagen have been used for over 30 years to estimate palaeodiet, subsistence strategy, breastfeeding duration and migration within burial populations. Recent developments in dentine microsampling allow improved temporal resolution for dietary patterns. A simple method is proposed which could be applied to human teeth to estimate chronological age represented by dentine microsamples in the direction of tooth growth, allowing comparison of dietary patterns between individuals and populations. The method is tested using profiles from permanent and deciduous teeth of two individuals. Using a diagrammatic representation of dentine development by approximate age for each human tooth (based on the Queen Mary University of London Atlas), this study estimated the age represented by each dentine section. Two case studies are shown: comparison of M1 and M2 from a 19th century individual from London, England, and identification of an unknown tooth from an Iron Age female adult from Scotland. The isotopic profiles demonstrate that variations in consecutively-forming teeth can be aligned using this method to extend the dietary history of an individual or identify an unknown tooth by matching the profiles.

A New Chronology for Rhafas, Northeast Morocco, Spanning the North African Middle Stone Age through to the Neolithic.

Science.gov (United States)

Doerschner, Nina; Fitzsimmons, Kathryn E; Ditchfield, Peter; McLaren, Sue J; Steele, Teresa E; Zielhofer, Christoph; McPherron, Shannon P; Bouzouggar, Abdeljalil; Hublin, Jean-Jacques

Archaeological sites in northern Africa provide a rich record of increasing importance for the origins of modern human behaviour and for understanding human dispersal out of Africa. However, the timing and nature of Palaeolithic human behaviour and dispersal across north-western Africa (the Maghreb), and their relationship to local environmental conditions, remain poorly understood. The cave of Rhafas (northeast Morocco) provides valuable chronological information about cultural changes in the Maghreb during the Palaeolithic due to its long stratified archaeological sequence comprising Middle Stone Age (MSA), Later Stone Age (LSA) and Neolithic occupation layers. 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 recently excavated section on the terrace in front of the cave entrance. We hereby provide a revised chronostratigraphy for the archaeological sequence at the site. We combine these results with geological and sedimentological multi-proxy investigations to gain insights into site formation processes and the palaeoenvironmental record of the region. The older sedimentological units at Rhafas were deposited between 135 ka and 57 ka (MIS 6 -MIS 3) and are associated with the MSA technocomplex. Tanged pieces start to occur in the archaeological layers around 109 ka, which is consistent with previously published chronological data from the Maghreb. A well indurated duricrust indicates favourable climatic conditions for the pedogenic cementation by carbonates of sediment layers at the site after 57 ka. Overlying deposits attributed to the LSA technocomplex yield ages of ~21 ka and ~15 ka, corresponding to the last glacial period, and fall well within the previously established occupation phase in the Maghreb. The last occupation phase at Rhafas took place during the Neolithic and is dated to ~7.8 ka.

A New Chronology for Rhafas, Northeast Morocco, Spanning the North African Middle Stone Age through to the Neolithic.

Directory of Open Access Journals (Sweden)

Nina Doerschner

Full Text Available Archaeological sites in northern Africa provide a rich record of increasing importance for the origins of modern human behaviour and for understanding human dispersal out of Africa. However, the timing and nature of Palaeolithic human behaviour and dispersal across north-western Africa (the Maghreb, and their relationship to local environmental conditions, remain poorly understood. The cave of Rhafas (northeast Morocco provides valuable chronological information about cultural changes in the Maghreb during the Palaeolithic due to its long stratified archaeological sequence comprising Middle Stone Age (MSA, Later Stone Age (LSA and Neolithic occupation layers. 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 recently excavated section on the terrace in front of the cave entrance. We hereby provide a revised chronostratigraphy for the archaeological sequence at the site. We combine these results with geological and sedimentological multi-proxy investigations to gain insights into site formation processes and the palaeoenvironmental record of the region. The older sedimentological units at Rhafas were deposited between 135 ka and 57 ka (MIS 6 -MIS 3 and are associated with the MSA technocomplex. Tanged pieces start to occur in the archaeological layers around 109 ka, which is consistent with previously published chronological data from the Maghreb. A well indurated duricrust indicates favourable climatic conditions for the pedogenic cementation by carbonates of sediment layers at the site after 57 ka. Overlying deposits attributed to the LSA technocomplex yield ages of ~21 ka and ~15 ka, corresponding to the last glacial period, and fall well within the previously established occupation phase in the Maghreb. The last occupation phase at Rhafas took place during the Neolithic and is dated to ~7.8 ka.

Chronology of the Middle to Upper Palaeolithic transition at Abric Romaní, Catalunya.

Science.gov (United States)

Camps, Marta; Higham, Thomas

2012-01-01

This paper presents new data from Abric Romaní, a key site in the region of Catalunya, northeastern Iberia, which is central to discussions of the transition between the Middle and Upper Palaeolithic in Europe. Until now, the Mid-Upper Paleolithic transition had been dated at the site through samples from the remaining baulk sections of levels A and B (typologically classified as 'earliest Aurignacian' and Mousterian, respectively) at the rear of the rockshelter, which were left from excavations in the late 1900s and early 1910s. We dated samples of bone and charcoal from these remnant sections with accelerator mass spectrometry (AMS) methods. We also analysed several humanly-modified artefacts (bone points and perforated shells) excavated from other areas of the same layers. From the initial series, we obtained ages of c. 20 ka BP (thousands of years before present); much younger than expected if they indeed dated to the early Upper Palaeolithic. We sampled additional material to test the robustness of these initial ages, and older determinations that were more comparable with the chronology outlined by Bischoff et al. (1988, 1994) resulted. All of the old and new results have been compared in a Bayesian model using the new INTCAL09 (14)C calibration dataset. The results appear to confirm the suggestion of some researchers (e.g., Zilhão and d'Errico, 1999) that there was no Aurignacian in the north of Iberia until c. 36,500 BP. The chronometric model shows a good level of agreement between the radiocarbon and U-series chronologies previously obtained, and the new results published in this paper. Copyright © 2011 Elsevier Ltd. All rights reserved.

Comparison of chronology of teeth eruption with body mass index among school children at Mangalore: A cross-sectional study

Directory of Open Access Journals (Sweden)

Nagaratna B Bagewadi

2016-01-01

Full Text Available Introduction: The development and eruption of the teeth, chronologies of human dentitions, dental age, and tooth formation standards are important aspects applied to dental practice. Body mass index (BMI gives an indication about the nutritional status of the child. It is relevant to know whether BMI has influenced chronology of tooth eruption pattern. Aim: To determine the eruption age of the different permanent teeth and compare eruption age with BMI in a group of children from selected schools in Mangalore. Materials and Methods: A cross-sectional study was designed in which 2928 children ranging in age from 5.5 to 15 years were included in the study. The children were divided into 20 chronological age groups with half year intervals. All the children were examined by a single examiner with the help of a trained assistant. The teeth were examined under natural light with mouth mirror. The comparison was made between mean eruption ages in males and females using the independent t-test. Results: There were 1526 males constituting 52.1% and 1402 females constituting 47.9% of the total sample of 2928 children. The mean age of eruption of maxillary central incisor, maxillary lateral incisor, maxillary and mandibular canines, maxillary and mandibular premolars, maxillary and mandibular second molars were found to have statistical significant with BMI. The mean age of eruption of the teeth in females was found to be earlier than in males, with the exception of the maxillary first molar which is earlier in males. Conclusion: Different categories of BMI were underweight, normal weight, risk of overweight and overweight, wherein overweight children had early eruption of teeth. Girls had early eruption time compared to boys.

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.

Demirjian's method in the estimation of age: A study on human third molars.

Science.gov (United States)

Lewis, Amitha J; Boaz, Karen; Nagesh, K R; Srikant, N; Gupta, Neha; Nandita, K P; Manaktala, Nidhi

2015-01-01

The primary aim of the following study is to estimate the chronological age based on the stages of third molar development following the eight stages (A to H) method of Demirjian et al. (along with two modifications-Orhan) and secondary aim is to compare third molar development with sex and age. The sample consisted of 115 orthopantomograms from South Indian subjects with known chronological age and gender. Multiple regression analysis was performed with chronological age as the dependable variable and third molar root development as independent variable. All the statistical analysis was performed using the SPSS 11.0 package (IBM ® Corporation). Statistically no significant differences were found in third molar development between males and females. Depending on the available number of wisdom teeth in an individual, R (2) varied for males from 0.21 to 0.48 and for females from 0.16 to 0.38. New equations were derived for estimating the chronological age. The chronological age of a South Indian individual between 14 and 22 years may be estimated based on the regression formulae. However, additional studies with a larger study population must be conducted to meet the need for population-based information on third molar development.

Brain Age in Early Stages of Bipolar Disorders or Schizophrenia.

Science.gov (United States)

Hajek, Tomas; Franke, Katja; Kolenic, Marian; Capkova, Jana; Matejka, Martin; Propper, Lukas; Uher, Rudolf; Stopkova, Pavla; Novak, Tomas; Paus, Tomas; Kopecek, Miloslav; Spaniel, Filip; Alda, Martin

2017-12-20

The greater presence of neurodevelopmental antecedants may differentiate schizophrenia from bipolar disorders (BD). Machine learning/pattern recognition allows us to estimate the biological age of the brain from structural magnetic resonance imaging scans (MRI). The discrepancy between brain and chronological age could contribute to early detection and differentiation of BD and schizophrenia. We estimated brain age in 2 studies focusing on early stages of schizophrenia or BD. In the first study, we recruited 43 participants with first episode of schizophrenia-spectrum disorders (FES) and 43 controls. In the second study, we included 96 offspring of bipolar parents (48 unaffected, 48 affected) and 60 controls. We used relevance vector regression trained on an independent sample of 504 controls to estimate the brain age of study participants from structural MRI. We calculated the brain-age gap estimate (BrainAGE) score by subtracting the chronological age from the brain age. Participants with FES had higher BrainAGE scores than controls (F(1, 83) = 8.79, corrected P = .008, Cohen's d = 0.64). Their brain age was on average 2.64 ± 4.15 years greater than their chronological age (matched t(42) = 4.36, P stages of BD showed comparable BrainAGE scores to controls (F(2,149) = 1.04, corrected P = .70, η2 = 0.01) and comparable brain and chronological age. Early stages of schizophrenia, but not early stages of BD, were associated with advanced BrainAGE scores. Participants with FES showed neurostructural alterations, which made their brains appear 2.64 years older than their chronological age. BrainAGE scores could aid in early differential diagnosis between BD and schizophrenia. © The Author(s) 2017. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com

Thermoluminescence dating. Application to the chronology of volcanic ashes

International Nuclear Information System (INIS)

Pilleyre, T.

1991-09-01

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

Retrieving chronological age from dental remains of early fossil hominins to reconstruct human growth in the past

OpenAIRE

Dean, M. Christopher

2010-01-01

A chronology of dental development in Pan troglodytes is arguably the best available model with which to compare and contrast reconstructed dental chronologies of the earliest fossil hominins. Establishing a time scale for growth is a requirement for being able to make further comparative observations about timing and rate during both dento-skeletal growth and brain growth. The absolute timing of anterior tooth crown and root formation appears not to reflect the period of somatic growth. In c...

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)

Ducrot, Jean

1979-01-01

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 [fr

Lack of Ach1 CoA-Transferase Triggers Apoptosis and Decreases Chronological Lifespan in Yeast

International Nuclear Information System (INIS)

Orlandi, Ivan; Casatta, Nadia; Vai, Marina

2012-01-01

ACH1 encodes a mitochondrial enzyme of Saccharomyces cerevisiae endowed with CoA-transferase activity. It catalyzes the CoASH transfer from succinyl-CoA to acetate generating acetyl-CoA. It is known that ACH1 inactivation results in growth defects on media containing acetate as a sole carbon and energy source which are particularly severe at low pH. Here, we show that chronological aging ach1Δ cells which accumulate a high amount of extracellular acetic acid display a reduced chronological lifespan. The faster drop of cell survival is completely abrogated by alleviating the acid stress either by a calorie restricted regimen that prevents acetic acid production or by transferring chronologically aging mutant cells to water. Moreover, the short-lived phenotype of ach1Δ cells is accompanied by reactive oxygen species accumulation, severe mitochondrial damage, and an early insurgence of apoptosis. A similar pattern of endogenous severe oxidative stress is observed when ach1Δ cells are cultured using acetic acid as a carbon source under acidic conditions. On the whole, our data provide further evidence of the role of acetic acid as cell-extrinsic mediator of cell death during chronological aging and highlight a primary role of Ach1 enzymatic activity in acetic acid detoxification which is important for mitochondrial functionality.

COCOA (Theobroma cacao) Polyphenol-Rich Extract Increases the Chronological Lifespan of Saccharomyces cerevisiae.

Science.gov (United States)

Baiges, I; Arola, L

2016-01-01

BACKGROUND: Saccharomyces cerevisiae is a model organism with conserved aging pathways. Yeast chronological lifespan experiments mimic the processes involved in human non-dividing tissues, such as the nervous system or skeletal muscle, and can speed up the search for biomolecules with potential anti-aging effects before proceeding to animal studies. OBJECTIVE: To test the effectiveness of a cocoa polyphenol-rich extract (CPE) in expanding the S. cerevisiae chronological lifespan in two conditions: in the stationary phase reached after glucose depletion and under severe caloric restriction. MEASUREMENTS: Using a high-throughput method, wild-type S. cerevisiae and its mitochondrial manganese-dependent superoxide dismutase null mutant (sod2Δ) were cultured in synthetic complete dextrose medium. After 2 days, 0, 5 and 20 mg/ml of CPE were added, and viability was measured throughout the stationary phase. The effects of the major components of CPE were also evaluated. To determine yeast lifespan under severe caloric restriction conditions, cultures were washed with water 24 h after the addition of 0 and 20 mg/ml of CPE, and viability was followed over time. RESULTS : CPE increased the chronological lifespan of S. cerevisiae during the stationary phase in a dose-dependent manner. A similar increase was also observed in (sod2Δ). None of the major CPE components (theobromine, caffeine, maltodextrin, (-)-epicatechin, (+)-catechin and procyanidin B2) was able to increase the yeast lifespan. CPE further increased the yeast lifespan under severe caloric restriction. CONCLUSION: CPE increases the chronological lifespan of S. cerevisiae through a SOD2-independent mechanism. The extract also extends yeast lifespan under severe caloric restriction conditions. The high-throughput assay used makes it possible to simply and rapidly test the efficacy of a large number of compounds on yeast aging, requiring only small amounts, and is thus a convenient screening assay to accelerate

MOD-AGE - an algorithm for age-depth model construction; U-series dated speleothems case study

Science.gov (United States)

Hercman, H.; Pawlak, J.

2012-04-01

We present MOD-AGE - a new system for chronology construction. MOD-AGE can be used for profiles that have been dated by different methods. As input data, the system uses the following basic measurements: activities, atomic ratios or age, as well as depth measurement. Based on probability distributions describing the measurement results, MOD-AGE estimates the age~depth relation and its confidence bands. To avoid the use of difficult-to-meet assumptions, MOD-AGE uses nonparametric methods. We applied a Monte Carlo simulation to model age and depth values based on the real distribution of counted data (activities, atomic ratios, depths etc.). Several fitting methods could be applied for estimating the relationships; based on several tests, we decide to use LOESS method (locally weighted scatterplot smoothing). The stratigraphic correction procedure applied in the MOD-AGE program uses a probability calculus, which assumes that the ages of all the samples are correctly estimated. Information about the probability distribution of the samples' ages is used to estimate the most probable sequence that is concordant according to the superposition rule. MOD-AGE is presented as a tool for the chronology construction of speleothems that have been analyzed by the U-series method, and it is compared to the StalAge algorithm presented by D. Scholtz and D.L Hoffmann (2011). Scholtz, D., Hoffmann, D. L., 2011. StalAge - An algorithm designed for construction of speleothem age models. Quaternary Geochronology 6, 369-382.

Astronautics and aeronautics, 1977: A chronology

Science.gov (United States)

Ritchie, E. H.

1986-01-01

This publication is a chronology of events during the year 1977 in the fields of aeronautical and space research, development, activity, and policy. It includes appendixes, an index, and illustrations. Chronological entries list sources for further inquiry.

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

Science.gov (United States)

Bazin, L.; Landais, A.; Lemieux-Dudon, B.; Toyé Mahamadou Kele, H.; Veres, D.; Parrenin, F.; Martinerie, P.; Ritz, C.; Capron, E.; Lipenkov, V.; Loutre, M.-F.; Raynaud, D.; Vinther, B.; Svensson, A.; Rasmussen, S. O.; Severi, M.; Blunier, T.; Leuenberger, M.; Fischer, H.; Masson-Delmotte, V.; Chappellaz, J.; Wolff, E.

2013-08-01

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 had 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 (thousands of years before present) (Lemieux-Dudon et al., 2010). In this paper, together with the companion paper of Veres et al. (2013), 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 framework, 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 additional 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 is now independent of other archives and shows only small differences, most of the time within the original uncertainty range calculated by Datice, when compared with the previous ice core reference age scale EDC3, the Dome F chronology, or using a comparison between speleothems and methane. For instance, the largest deviation between AICC2012 and EDC3 (5.4 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.

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

Perceived age is associated with bone status in women aged 25-93 years

DEFF Research Database (Denmark)

Nielsen, Barbara Rubek; Linneberg, Allan; Christensen, Kaare

2015-01-01

) or "looking young" (LY). Linear mixed models and general linear models fitted with BMD/TBS as outcome and either RPACA or LO/LY as an independent variable, considering chronological age. Estimates of RPACA were all negative; i.e., an increase in RPAC is associated with lower BMD, consistent......Higher perceived age (PA) is reported to be associated with age-related diseases. Because osteoporosis is considered an age-related disease, we hypothesized that age perceived from photographs is associated with bone mineral density (BMD)/trabecular bone score (TBS) when controlled...... for chronological age. This is a cross-sectional study of 460 women aged 25-93 years. BMD/TBS was measured. Twenty physicians assessed age from facial and whole-body photographs. Residual PA (RPACA) was calculated from the regression of PA on chronological age. Participants were divided into "looking old" (LO...

Chronology of Chichen Izta, evidences by thermoluminescence

International Nuclear Information System (INIS)

Ramirez, A.; Schaaf, P.; Gonzalez, P.R.; Chung, H.

2002-01-01

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 ( 40 K) by means of the microanalysis technique in the scanning electron microscope was determined, while the uranium content (2 38 U) and thorium ( 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 4 :Dy + Ptfe once the paleodose was known and the annual dose rate of each sample of its age was estimated. (Author)

Effects of Long-Term Storage Time and Original Sampling Month on Biobank Plasma Protein Concentrations

Directory of Open Access Journals (Sweden)

Stefan Enroth

2016-10-01

Full Text Available The quality of clinical biobank samples is crucial to their value for life sciences research. A number of factors related to the collection and storage of samples may affect the biomolecular composition. We have studied the effect of long-time freezer storage, chronological age at sampling, season and month of the year and on the abundance levels of 108 proteins in 380 plasma samples collected from 106 Swedish women. Storage time affected 18 proteins and explained 4.8–34.9% of the observed variance. Chronological age at sample collection after adjustment for storage-time affected 70 proteins and explained 1.1–33.5% of the variance. Seasonal variation had an effect on 15 proteins and month (number of sun hours affected 36 proteins and explained up to 4.5% of the variance after adjustment for storage-time and age. The results show that freezer storage time and collection date (month and season exerted similar effect sizes as age on the protein abundance levels. This implies that information on the sample handling history, in particular storage time, should be regarded as equally prominent covariates as age or gender and need to be included in epidemiological studies involving protein levels.

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

Directory of Open Access Journals (Sweden)

L. Bazin

2013-08-01

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 had 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 (thousands of years before present (Lemieux-Dudon et al., 2010. In this paper, together with the companion paper of Veres et al. (2013, 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 framework, 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 additional 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 is now independent of other archives and shows only small differences, most of the time within the original uncertainty range calculated by Datice, when compared with the previous ice core reference age scale EDC3, the Dome F chronology, or using a comparison between speleothems and methane. For instance, the largest deviation between AICC2012 and EDC3 (5.4 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.

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

Science.gov (United States)

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

2013-01-01

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

A chronology for glacial Lake Agassiz shorelines along Upham's namesake transect

Science.gov (United States)

Lepper, Kenneth; Buell, Alex W.; Fisher, Timothy G.; Lowell, Thomas V.

2013-07-01

Four traditionally recognized strandline complexes in the southern basin of glacial Lake Agassiz are the Herman, Norcross, Tintah and Campbell, whose names correspond to towns in west-central Minnesota that lie on a linear transect defined by the Great Northern railroad grade; the active corridor for commerce at the time when Warren Upham was mapping and naming the shorelines of Lake Agassiz (ca.1880-1895). Because shorelines represent static water planes, their extension around the lake margin establishes time-synchronous lake levels. Transitions between shoreline positions represent significant water-level fluctuations. However, geologic ages have never been obtained from sites near the namesake towns in the vicinity of the southern outlet. Here we report the first geologic ages for Lake Agassiz shorelines obtained at field sites along the namesake transect, and evaluate the emerging chronology in light of other paleoclimate records. Our current work from 11 sampling sites has yielded 16 independent ages. These results combined with a growing OSL age data set for Lake Agassiz's southern basin provide robust age constraints for the Herman, Norcross and Campbell strandlines with averages and standard deviations of 14.1 ± 0.3 ka, 13.6 ± 0.2 ka, and 10.5 ± 0.3 ka, respectively.

Astronautics and Aeronautics, 1986-1990: A Chronology

Science.gov (United States)

Gawdiak, Ihor Y.; Miro, Ramon J.; Stueland, Sam

1997-01-01

This chronology of events in aeronautics, aviation, space science, and space exploration was prepared by the Federal Research Division of the LibrarY of Congress for the History Division of the National Aeronautics and Space Administration (NASA). It covers the years 1996-1990 and continues the series of annual chronologies published by NASA. The present volume returns to the format used in the Astronautics and Aeronautics, 1979-1984: A Chronology volume. It also integrates in a single table the information presented in two or three previous publications.

Astronautics and Aeronautics, 1991-1995: A Chronology

Science.gov (United States)

Gawdiak, Ihor Y. (Compiler); Shetland, Charles (Compiler)

2000-01-01

This chronology of events in aeronautics, aviation, space science, and space exploration was prepared by the Federal Research Division of the Library of Congress and RSIS for the History Division of the National Aeronautics and Space Administration (NASA). It covers the years 1991-1995 and continues the series of annual chronologies published by NASA. The present volume uses the format of the previous edition of this series, Astronautics and Aeronautics, 1986-1990: A Chronology. It also integrates, in the appendices, information presented in previous publication

Evaluation of the accuracy of Demirjian method for estimation of dental age among 6-12 years of children in Navi Mumbai: A radiographic study.

Science.gov (United States)

Hegde, Rahul J; Khare, Sumedh Suhas; Saraf, Tanvi A; Trivedi, Sonal; Naidu, Sonal

2015-01-01

Dental formation is superior to eruption as a method of dental age (DA) assessment. Eruption is only a brief occurrence, whereas formation may be related at different chronologic age levels, thereby providing a precise index for determining DA. The study was designed to determine the nature of inter-relationship between chronologic and DA. Age estimation depending upon tooth formation was done by Demirjian method and accuracy of Demirjian method was also evaluated. The sample for the study consisted of 197 children of Navi Mumbai. Significant positive correlation was found between chronologic age and DA that is, (r = 0.995), (P Mumbai (Maharashtra - India) population. Demirjian method showed high accuracy when applied to Navi Mumbai (Maharashtra - India) population.

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

Energy Technology Data Exchange (ETDEWEB)

Pittauerova, D.; Fischer, H. W. [Institute of Environmental Physics, University of Bremen, Bremen (Germany); Mulitza, S. [MARUM - Center for Marine Environmental Sciences, University of Bremen, (Germany)

2013-07-15

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. {sup 210}Pb, {sup 226}Ra and {sup 137}Cs 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 {sup 14}C. The {sup 210}Pb age allowed the estimation of the local radiocarbon reservoir age. Application of {sup 210}Pb and {sup 137}Cs 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)

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...

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

International Nuclear Information System (INIS)

Bridge, M.C.; Ogden, J.

1986-01-01

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

Is Greulich–Pyle age estimation applicable for determining maturation in male Africans?

Directory of Open Access Journals (Sweden)

Alan G. Morri

2012-09-01

Full Text Available Skeletal age estimation as a means of assessing development and skeletal maturation in children and adolescents is of great importance for clinical and forensic purposes. The skeletal age of a test population is estimated by comparison with established standards, the most common standards being those in the Radiographic atlas of skeletal development of the hand and wristpublished by Greulich and Pyle in 1959. These standards are based on the assumption that skeletal maturity in male individuals is attained by the chronological age of 19 years. Although they have been widely tested, the applicability of these standards to contemporary populations has yet to be tested on a population of African biological origin living in South Africa. We therefore estimated the skeletal age of 131 male Africans aged between 13 and 21 years, using the Greulich–Pyle method which we applied to pre-existing hand–wrist radiographs. Estimated skeletal age was compared to the known chronological age for each radiograph. Skeletal age was on average approximately 6 months younger than chronological age. The Greulich–Pyle method underestimated skeletal age for approximately 74%of the sample and overestimated skeletal age for 26%of the sample. Skeletal maturity as characterised by complete epiphyseal fusion occurred approximately 2.1 years later than Greulich and Pyle’s estimate of 19 years. Thus skeletal maturation was still in progress in a large proportion of the 20- and 21-year-old individuals in our study. The Greulich–Pyle method showed high precision but low accuracy and was therefore not directly applicable to African male individuals. Formulation of skeletal age estimation standards specific to South African populations is therefore recommended.

High-resolution OSL chronology of a sediment core from Lake Nam Co on the southern Tibetan Plateau: Comparison with radiocarbon dating

Science.gov (United States)

Long, Hao; Shen, Ji; Haberzettl, Torsten; Fuchs, Markus; Frechen, Manfred; Wang, Junbo

2013-04-01

Numerous studies on lake sediment cores from the Tibetan Plateau aimed to reconstruct spatial and temporal changes of the late Glacial and Holocene monsoon variations, which are characterized by fluctuations in precipitation and expansion of monsoonal air masses across the Plateau. Accurate and reliable dating of lacustrine deposits is of crucial importance in both the reconstruction of palaeolake and palaeoclimate evolution and the understanding of the mechanisms for climate changes, especially abrupt changes of regional-hemispheric hydrological circulation. Radiocarbon dating is the most commonly used method for establishing chronologies of lake sediments. However, 14C dating of such sediments could be problematic due to the lack of organic matter or a reservoir effect, which appears common in radiocarbon dating of lacustrine sediments from the Tibetan Plateau. In this study, ca. 10.5 m long core (NC core) was retrieved from the water depth of 93 m at Nam Co Lake, which is the second largest saline lake in China, located on the southern Tibetan Plateau. For this core, high-resolution samples (23 samples) were obtained for optically stimulated luminescence (OSL) dating. Quartz of fine-grain (4-11 μm) fraction were extracted from this samples for OSL dating, which is compared with the 14C chronology of NC core based on accelerator mass spectrometry (AMS) dating of bulk organic matter of 22 samples. The sample from the top of NC core was dated to approximate zero age, indicating the sediments bleached well before deposition. Luminescence behaviors of the study samples further confirmed the robustness of OSL ages. Comparison between OSL and 14C ages suggested that: (1) two kinds of ages are in agreement within error from top to 1.8 m, (2) from 1.8 m to the base of NC core, the 14C ages show a general trend to ca. 4 ka higher ages than the OSL ages. Although 14C dating overestimate the ages from 1.8 m to base, they still show the general trend in sedimentation rate

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

shifted northward at ~30 ka BP. We have not yet been able to date LGM moraines as far south as ~40°, which would indicate the transition of precipitation- to temperature-sensitive glaciers. Instead, our preliminary exposure age chronology from Valle Rucachoroi (~39°S, Argentina) suggests that the maximum glaciation there occurred also at ~30 ka BP, but that the valleys became ice-free only by ~15 ka BP. Samples from moraines in the cirques are currently in progress and may document lateglacial re-advances.

Supported Lead in Pb-210 Chronology

Energy Technology Data Exchange (ETDEWEB)

Pittauerova, D.; Hettwig, B.; Fischer, H. W. [Institute of Environmental Physics, University of Bremen, Bremen (Germany)

2013-07-15

A widely applied method of supported lead estimation in sediments using gamma spectrometric {sup 226}Ra determination via {sup 222}Rn short lived daughter products relies on radioactive equilibrium between {sup 226}Ra and {sup 222}Rn being established after sealing the samples. Advantages and disadvantages of methods of {sup 226}Ra estimation in sediments, using either {sup 222}Rn daughter products or direct estimation by 186.2 keV gamma emissions are discussed. An equilibrium experiment was performed using test samples and in one case radioactive equilibrium was not reached. On a theoretical sediment profile it was shown how systematic errors in supported {sup 210}Pb estimation can lead to incorrect interpretations of {sup 210}Pb{sub xs} profiles and therefore affect {sup 210}Pb derived chronologies. (author)

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

Science.gov (United States)

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

2013-01-01

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

Evaluation of the Applicability of Different Age Determination Methods for Estimating Age of the Endangered African Wild Dog (Lycaon Pictus.

Directory of Open Access Journals (Sweden)

Moreangels M Mbizah

Full Text Available African wild dogs (Lycaon pictus are endangered and their population continues to decline throughout their range. Given their conservation status, more research focused on their population dynamics, population growth and age specific mortality is needed and this requires reliable estimates of age and age of mortality. Various age determination methods from teeth and skull measurements have been applied in numerous studies and it is fundamental to test the validity of these methods and their applicability to different species. In this study we assessed the accuracy of estimating chronological age and age class of African wild dogs, from dental age measured by (i counting cementum annuli (ii pulp cavity/tooth width ratio, (iii tooth wear (measured by tooth crown height (iv tooth wear (measured by tooth crown width/crown height ratio (v tooth weight and (vi skull measurements (length, width and height. A sample of 29 African wild dog skulls, from opportunistically located carcasses was analysed. Linear and ordinal regression analysis was done to investigate the performance of each of the six age determination methods in predicting wild dog chronological age and age class. Counting cementum annuli was the most accurate method for estimating chronological age of wild dogs with a 79% predictive capacity, while pulp cavity/tooth width ratio was also a reliable method with a 68% predictive capacity. Counting cementum annuli and pulp cavity/tooth width ratio were again the most accurate methods for separating wild dogs into three age classes (6-24 months; 25-60 months and > 60 months, with a McFadden's Pseudo-R2 of 0.705 and 0.412 respectively. The use of the cementum annuli method is recommended when estimating age of wild dogs since it is the most reliable method. However, its use is limited as it requires tooth extraction and shipping, is time consuming and expensive, and is not applicable to living individuals. Pulp cavity/tooth width ratio is a

Initial chronology of a recently discovered hydrothermal field at 14°45‧N, Mid-Atlantic Ridge

Science.gov (United States)

Lalou, Claude; Reyss, Jean Louis; Brichet, Evelyne; Krasnov, Sergey; Stepanova, Tamara; Cherkashev, Georgiy; Markov, Vladimir

1996-11-01

Two expeditions of the 'Sevmorgeologija' association (1991-1994) led to the discovery of two new hydrothermal sites on the Mid Atlantic Ridge (MAR), south of the 15°20‧ North Fracture Zone, one around 14°45‧N and the other around 14°42‧N. The northern one, between 14°45‧ and 14°45.3‧N has been studied in detail. About 12 mounds have been mapped and 3 of them have been sampled using a large hydraulic grab sampler. The largest one is about 200 m long and 200 m wide. When progressively moving up on the slope of an uplifted block of the rift valley floor, the sulphide samples have revealed ages ranging from about 10 ka to 60 ka. The ages were obtained using the 230Th/234U dating method used for chronological studies of diverse hydrothermal fields. The general picture of this lateral location of the samples of different ages provides evidence of a shift in the focus of hydrothermal activity with time. Moreover, there were rejuvenation stages of hydrothermal activity, including black and white smokers.

Constructing deposition chronologies for peat deposits using radiocarbon dating

Directory of Open Access Journals (Sweden)

N. Piotrowska

2011-06-01

Full Text Available Radiocarbon dating is one of the main methods used to establish peat chronologies. This article reviews the basis of the method and its application to dating of peat deposits. Important steps in the radiocarbon dating procedure are described, including selection and extraction of material (and fractions for dating, chemical and physical preparation of media suitable for measurements, measurements of 14C activity or concentration, calculations, calibration of results and age-depth modelling.

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

Chronology. Classroom Focus.

Science.gov (United States)

McGoldrick, Neale

1995-01-01

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

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

DEFF Research Database (Denmark)

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

2012-01-01

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

Paleo Data Assimilation of Pseudo-Tree-Ring-Width Chronologies in a Climate Model

Science.gov (United States)

Fallah Hassanabadi, B.; Acevedo, W.; Reich, S.; Cubasch, U.

2016-12-01

Using the Time-Averaged Ensemble Kalman Filter (EnKF) and a forward model, we assimilate the pseudo Tree-Ring-Width (TRW) chronologies into an Atmospheric Global Circulation model. This study investigates several aspects of Paleo-Data Assimilation (PDA) within a perfect-model set-up: (i) we test the performance of several forward operators in the framework of a PDA-based climate reconstruction, (ii) compare the PDA-based simulations' skill against the free ensemble runs and (iii) inverstigate the skill of the "online" (with cycling) DA and the "off-line" (no-cycling) DA. In our experiments, the "online" (with cycling) PDA approach did not outperform the "off-line" (no-cycling) one, despite its considerable additional implementation complexity. On the other hand, it was observed that the error reduction achieved by assimilating a particular pseudo-TRW chronology is modulated by the strength of the yearly internal variability of the model at the chronology site. This result might help the dendrochronology community to optimize their sampling efforts.

A 400-year tree-ring chronology from the tropical treeline of North America.

Science.gov (United States)

Biondi, F

2001-05-01

High-elevation sites in the tropics may be particularly sensitive to rapid climate change. By sampling treeline populations, I have developed the first extensive (> 300 years) tree-ring chronology in tropical North America. The site is Nevado de Colima, at the western end of the Mexican Neovolcanic Belt, and the species studied is Mexican mountain pine (Pinus hartwegii). Despite past logging in the area, 300 to 500-year old pines were found at 3600-3700 m elevation, about 300 m below the present treeline. The Nevado de Colima tree-ring chronology is well replicated from 1600 to 1997. Calibration with Colima climatic records points to summer monsoon precipitation as the strongest dendroclimatic signal. Most trees also exhibit extremely low growth in 1913 and 1914, following the January 1913 Plinian eruption of the Volcan de Colima. Because P. hartwegii is found on top of high mountains from Mexico to Guatemala, there is potential for developing a network of tropical treeline chronologies.

DNA methylation-based measures of biological age: meta-analysis predicting time to death

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Chen, Brian H.; Marioni, Riccardo E.; Colicino, Elena; Peters, Marjolein J.; Ward-Caviness, Cavin K.; Tsai, Pei-Chien; Roetker, Nicholas S.; Just, Allan C.; Demerath, Ellen W.; Guan, Weihua; Bressler, Jan; Fornage, Myriam; Studenski, Stephanie; Vandiver, Amy R.; Moore, Ann Zenobia; Tanaka, Toshiko; Kiel, Douglas P.; Liang, Liming; Vokonas, Pantel; Schwartz, Joel; Lunetta, Kathryn L.; Murabito, Joanne M.; Bandinelli, Stefania; Hernandez, Dena G.; Melzer, David; Nalls, Michael; Pilling, Luke C.; Price, Timothy R.; Singleton, Andrew B.; Gieger, Christian; Holle, Rolf; Kretschmer, Anja; Kronenberg, Florian; Kunze, Sonja; Linseisen, Jakob; Meisinger, Christine; Rathmann, Wolfgang; Waldenberger, Melanie; Visscher, Peter M.; Shah, Sonia; Wray, Naomi R.; McRae, Allan F.; Franco, Oscar H.; Hofman, Albert; Uitterlinden, André G.; Absher, Devin; Assimes, Themistocles; Levine, Morgan E.; Lu, Ake T.; Tsao, Philip S.; Hou, Lifang; Manson, JoAnn E.; Carty, Cara L.; LaCroix, Andrea Z.; Reiner, Alexander P.; Spector, Tim D.; Feinberg, Andrew P.; Levy, Daniel; Baccarelli, Andrea; van Meurs, Joyce; Bell, Jordana T.; Peters, Annette; Deary, Ian J.; Pankow, James S.; Ferrucci, Luigi; Horvath, Steve

2016-01-01

Estimates of biological age based on DNA methylation patterns, often referred to as “epigenetic age”, “DNAm age”, have been shown to be robust biomarkers of age in humans. We previously demonstrated that independent of chronological age, epigenetic age assessed in blood predicted all-cause mortality in four human cohorts. Here, we expanded our original observation to 13 different cohorts for a total sample size of 13,089 individuals, including three racial/ethnic groups. In addition, we examined whether incorporating information on blood cell composition into the epigenetic age metrics improves their predictive power for mortality. All considered measures of epigenetic age acceleration were predictive of mortality (p≤8.2×10−9), independent of chronological age, even after adjusting for additional risk factors (p<5.4×10−4), and within the racial/ethnic groups that we examined (non-Hispanic whites, Hispanics, African Americans). Epigenetic age estimates that incorporated information on blood cell composition led to the smallest p-values for time to death (p=7.5×10−43). Overall, this study a) strengthens the evidence that epigenetic age predicts all-cause mortality above and beyond chronological age and traditional risk factors, and b) demonstrates that epigenetic age estimates that incorporate information on blood cell counts lead to highly significant associations with all-cause mortality. PMID:27690265

Luminescence chronology of loess-paleosol sequences from Canterbury, South Island, New Zealand

International Nuclear Information System (INIS)

Berger, G.W.; Pillans, B.J.; Tonkin, P.J.

2001-01-01

The extensive Quaternary loess-paleosol deposits of South Island, New Zealand, represent one of the major proxy records of paleoclimatic changes in the Southern Hemisphere. We attempted to produce the first numeric chronology of these subaerial sequences in the Canterbury region by using thermoluminescence and infrared-stimulated luminescence dating methods. We examined five exposures: a 6 m thick section at Cust, north of Christchurch; two thicker (c. 14 m) sequences on Banks Peninsula (Barrys Bay and Onawe sites); farther south, a c. 12 m sequence in Timaru; and a c. 7 m sequence on the coast at the Normanby site near Timaru. Our results are largely based on single experiments per sample, and therefore provide imprecise ages for several of the older samples. The most satisfactory results are those from the youngest site (Cust), for which three samples were dated. Here, phases of maximum loess deposition are dated at 73 +/- 13 ka (basal loess-paleosol unit L3), 41 +/- 5 ka (basal L2), and 27 +/- 3 ka (basal L1). At Barrys Bay an age of 70 +/- 15 ka was obtained in the basal L1, and at Timaru two separate samples in the base of L1 also yielded ages of c. 70 ka, thus correlating the entire Cust loess sequence with the L1 loess unit at these two other study sites. Only at Barrys Bay were ages (c. 130-250 ka) in stratigraphic order obtained for older samples (units L2 and deeper). At the other sites, some samples in the sub-L1 units gave age reversals, and some (including the oldest sample at Barrys Bay) yielded poor precision (e.g., 20%). Units L2 at Timaru and Barrys Bay may correlate to all or part of MIS 6; however, the poor precision and some age reversals in other units at these sites and at Normanby and Onawe preclude any unambiguous correlations between sites or to the MIS time-scale. Nevertheless, in the absence of any prior numeric ages, these first results serve as a basis for more precise future dating of these units. Although these reconnaissance dating

Moonrise: Sampling the South Pole-Aitken Basin to Address Problems of Solar System Significance

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Zeigler, R. A.; Jolliff, B. L.; Korotev, R. L.; Shearer, C. K.

2016-01-01

A mission to land in the giant South Pole-Aitken (SPA) Basin on the Moon's southern farside and return a sample to Earth for analysis is a high priority for Solar System Science. Such a sample would be used to determine the age of the SPA impact; the chronology of the basin, including the ages of basins and large impacts within SPA, with implications for early Solar System dynamics and the magmatic history of the Moon; the age and composition of volcanic rocks within SPA; the origin of the thorium signature of SPA with implications for the origin of exposed materials and thermal evolution of the Moon; and possibly the magnetization that forms a strong anomaly especially evident in the northern parts of the SPA basin. It is well known from studies of the Apollo regolith that rock fragments found in the regolith form a representative collection of many different rock types delivered to the site by the impact process (Fig. 1). Such samples are well documented to contain a broad suite of materials that reflect both the local major rock formations, as well as some exotic materials from far distant sources. Within the SPA basin, modeling of the impact ejection process indicates that regolith would be dominated by SPA substrate, formed at the time of the SPA basin-forming impact and for the most part moved around by subsequent impacts. Consistent with GRAIL data, the SPA impact likely formed a vast melt body tens of km thick that took perhaps several million years to cool, but that nonetheless represents barely an instant in geologic time that should be readily apparent through integrated geochronologic studies involving multiple chronometers. It is anticipated that a statistically significant number of age determinations would yield not only the age of SPA but also the age of several prominent nearby basins and large craters within SPA. This chronology would provide a contrast to the Imbrium-dominated chronology of the nearside Apollo samples and an independent test of

[Chronologic analysis of clonal evolution in acquired aplastic anemia and sMDS].

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Yoshizato, Tetsuichi

2016-04-01

Acquired aplastic anemia (AA) is a prototype of idiopathic bone marrow failure, which is caused by immune-mediated destruction of hematopoietic progenitors but is also characterized by frequent evolution to clonal myeloid disorders, such as myelodysplastic syndromes or acute myeloid leukemia. However, the chronological behavior of the clonality and its link to myelodysplastic syndrome or acute myeloid leukemia has not been fully explored. To define the clonality and its chronological behavior in AA, we performed targeted sequencing (N=439) in cases with AA. Somatic mutations were detected in 1/3 of our cases. Mutations were most frequently found in DNMT3A, followed by BCOR, PIGA and ASXL1. The prevalence of mutations increased with age. The clone sizes in DNMT3A and ASXL1 were prone to increase, whereas those of BCOR and PIGA were more likely to decrease or remain stable. Mutations in PIGA, BCOR and BCORL1 correlated with a better response to immunosuppressive therapy and more favorable survival. On the other hand, other mutations were associated with worse outcomes. The chronological dynamics of clonality showed marked variability and were not necessarily associated with prognosis.

Chronology and development of the Chalcolithic necropolis of Varna I

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Raiko Krauß

2018-01-01

Full Text Available In the following paper, we present the main results of our now completed studies of the Varna I cemetery, based on the excavations undertaken by Ivan Ivanov in the years 1972–1991. The richness of the assemblages is singular in Old World prehistory. To tackle the question of its inter­nal, chronological development, we applied correspondence analysis (CA to a newly created database that includes the inventories of all presently known graves, symbolic burials and find de­posits. The rank order of the seriated inventories was used to establish a CA-based 14C-age model for wiggle matching. In combination with topographic observations and social network analysis (SNA, our studies provide a new understanding both of the chronological and spatial distribution of the graves and burial goods, as well as new insights into the social structure, gender roles, individual relation­ships and ritual practices of the Chalcolithic community.

Functional age as an indicator of reservoir senescence

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Miranda, Leandro E.; Krogman, R. M.

2015-01-01

It has been conjectured that reservoirs differ in the rate at which they manifest senescence, but no attempt has been made to find an indicator of senescence that performs better than chronological age. We assembled an indicator of functional age by creating a multimetric scale consisting of 10 metrics descriptive of reservoir environments that were expected to change directionally with reservoir senescence. In a sample of 1,022 U.S. reservoirs, chronological age was not correlated with functional age. Functional age was directly related to percentage of cultivated land in the catchment and inversely related to reservoir depth. Moreover, aspects of reservoir fishing quality and fish population characteristics were related to functional age. A multimetric scale to indicate reservoir functional age presents the possibility for management intervention from multiple angles. If a reservoir is functionally aging at an accelerated rate, action may be taken to remedy the conditions contributing most to functional age. Intervention to reduce scores of selected metrics in the scale can potentially reduce the rate of senescence and increase the life expectancy of the reservoir. This leads to the intriguing implication that steps can be taken to reduce functional age and actually make the reservoir grow younger.

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.

Climatically sensitive tree-ring chronologies from Crimea, Ukraine

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Solomina, O.; Davi, N.; D Arrigo, R.

2003-04-01

Several tree species in Crimea can reach ages of 1000 years or more (Crimea..., 1999), including Taxus baccata L., Arbutus andrachne L., Quercus pubescens Willd, Quercus petraea (Mattuschka) Liebl., Quercus robur L., Juniperus excelsa M.B., and Pistacia mutica Fisch.et Mey. In September 2002, we collected samples from several long-lived tree sites described in the literature (Vulf, 1948, Ivanenko, 1951, Ena, 1983, Podgorniy, 1990), located in the mountains of Central Crimea (Sokolinoye, Chufut-Kale, Chelter) and on the coast of the Black Sea (Ai-Todor, Kharaks, Ai-Petri). The trees sampled generally had 300-350 rings. At Ai-Todor, most oaks, junipers, and pistachio showed decay. However, enough samples of oak, juniper and pine were collected to build three chronologies with good replication over the last 350 years. Long meteorological records (for Sevastopol since 1821, Ai-Petri and Yalta since the 1880's) as well as detailed historical data on extreme climatic events since 1687 (summarized by Borisov 1956) are available for this area and can be used to calibrate and verify the tree growth/climate models. Resulting dendroclimatic reconstructions will be the first from this region. The tree-ring time-series may also be used for archaeological dating of historical wood from several medieval fortresses, towns and palaces. In turn, the archaeological wood could be used to extend the tree-ring time series. Stalactites and stalagmites (Dubliansky, 1977) found in numerous caves, as well as 4000-years old laminated lake sediments (Shostakovich, 1934) are also potentially important sources of paleoclimatic information in the area.

Perceived age change after aesthetic facial surgical procedures quantifying outcomes of aging face surgery.

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Chauhan, Nitin; Warner, Jeremy P; Adamson, Peter A

2012-01-01

To quantify the degree of perceived age change after aesthetic facial surgical procedures to provide an objective measure of surgical success. Sixty patients undergoing various aging face surgical procedures were randomly chosen for analysis. Preoperative and postoperative photographs were evaluated. Raters were presented with photographs in a random assortment and were asked to estimate the age of the patient. Perceived age difference was defined as the difference between the chronological age and the estimated age, and the change in this value after surgery was the chief outcome of interest. Statistical models were designed to account for any effects of interrater differences, preoperative chronological age, rater group, photograph order, or surgical procedure performed. Our patient population was divided into the following 3 groups based on the surgical procedure performed: group 1 (face- and neck-lift [22 patients]), group 2 (face- and neck-lift and upper and lower blepharoplasty [17 patients]), and group 3 (face- and neck-lift, upper and lower blepharoplasty, and forehead-lift [21 patients]). Adjusted means demonstrated that patient ages were estimated to be 1.7 years younger than their chronological age before surgery and 8.9 years younger than their chronological age after surgery. The effect was less substantial for group 1 patients and was most dramatic for group 3 patients, who had undergone all 3 aging face surgical procedures. Our study is novel in that it quantifies the degree of perceived age change after aging face surgical procedures and demonstrates a significant and consistent reduction in perceived age after aesthetic facial surgery. This effect is more substantial when the number of surgical procedures is increased, an effect unrelated to the preoperative age of a patient and unaffected by other variables that we investigated. The ability to perceive age correctly is accurate and consistent.

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

NARCIS (Netherlands)

Melis, J.P.; Jonker, M.J.; Vijg, J.; Hoeijmakers, J.H.; Breit, T.M.; van Steeg, H.

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

Computer-assisted analysis of cervical vertebral bone age using cephalometric radiographs in Brazilian subjects.

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Caldas, Maria de Paula; Ambrosano, Gláucia Maria Bovi; Haiter Neto, Francisco

2010-01-01

The aims of this study were to develop a computerized program for objectively evaluating skeletal maturation on cephalometric radiographs, and to apply the new method to Brazilian subjects. The samples were taken from the patient files of Oral Radiological Clinics from the North, Northeast, Midwest and South regions of the country. A total of 717 subjects aged 7.0 to 15.9 years who had lateral cephalometric radiographs and hand-wrist radiographs were selected. A cervical vertebral computerized analysis was created in the Radiocef Studio 2 computer software for digital cephalometric analysis, and cervical vertebral bone age was calculated using the formulas developed by Caldas et al.17 (2007). Hand-wrist bone age was evaluated by the TW3 method. Analysis of variance (ANOVA) and the Tukey test were used to compare cervical vertebral bone age, hand-wrist bone age and chronological age (P cervical vertebral bone age and chronological age in all regions studied. When analyzing bone age, it was possible to observe a statistically significant difference between cervical vertebral bone age and hand-wrist bone age for female and male subjects in the North and Northeast regions, as well as for male subjects in the Midwest region. No significant difference was observed between bone age and chronological age in all regions except for male subjects in the North and female subjects in the Northeast. Using cervical vertebral bone age, it might be possible to evaluate skeletal maturation in an objective manner using cephalometric radiographs.

Gratitude From Early Adulthood to Old Age.

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Allemand, Mathias; Hill, Patrick L

2016-02-01

Are there age differences in gratitude from early adulthood to old age? The current studies tested several ways by which an association between age and dispositional gratitude may present, by considering multiple measures on both fronts. We used data from three cross-sectional studies (total N = 1,736; total age range: 19-94). The results indicated that (a) age effects in gratitude are more likely to occur for subjective age in terms of future time perspective (i.e., people's perceptions of their remaining opportunities and time) than chronological age; (b) chronological age effects are more domain specific than general in nature; and (c) they are more likely to occur for the instrumental domain as compared to the interpersonal domain. Finally, the results indicated that (d) perceived future time, particularly with respect to remaining opportunities, mediates the relation between chronological age and general gratitude. Overall, the findings suggest that gratitude is subject to a variety of developmental influences across adulthood. © 2014 Wiley Periodicals, Inc.

Bayesian chronological analyses consistent with synchronous age of 12,835-12,735 Cal B.P. for Younger Dryas boundary on four continents.

Science.gov (United States)

Kennett, James P; Kennett, Douglas J; Culleton, Brendan J; Aura Tortosa, J Emili; Bischoff, James L; Bunch, Ted E; Daniel, I Randolph; Erlandson, Jon M; Ferraro, David; Firestone, Richard B; Goodyear, Albert C; Israde-Alcántara, Isabel; Johnson, John R; Jordá Pardo, Jesús F; Kimbel, David R; LeCompte, Malcolm A; Lopinot, Neal H; Mahaney, William C; Moore, Andrew M T; Moore, Christopher R; Ray, Jack H; Stafford, Thomas W; Tankersley, Kenneth Barnett; Wittke, James H; Wolbach, Wendy S; West, Allen

2015-08-11

The Younger Dryas impact hypothesis posits that a cosmic impact across much of the Northern Hemisphere deposited the Younger Dryas boundary (YDB) layer, containing peak abundances in a variable assemblage of proxies, including magnetic and glassy impact-related spherules, high-temperature minerals and melt glass, nanodiamonds, carbon spherules, aciniform carbon, platinum, and osmium. Bayesian chronological modeling was applied to 354 dates from 23 stratigraphic sections in 12 countries on four continents to establish a modeled YDB age range for this event of 12,835-12,735 Cal B.P. at 95% probability. This range overlaps that of a peak in extraterrestrial platinum in the Greenland Ice Sheet and of the earliest age of the Younger Dryas climate episode in six proxy records, suggesting a causal connection between the YDB impact event and the Younger Dryas. Two statistical tests indicate that both modeled and unmodeled ages in the 30 records are consistent with synchronous deposition of the YDB layer within the limits of dating uncertainty (∼ 100 y). The widespread distribution of the YDB layer suggests that it may serve as a datum layer.

14C age determination for human bones during the Yayoi period - the calibration ambiguity around 2400 BP and the marine reservoir effect

International Nuclear Information System (INIS)

Mihara, S.; Miyamoto, K.; Nakamura, T.; Koike, H.

2004-01-01

14 C ages for Japanese prehistoric samples from the Latest Jomon period to the early Yayoi period have a calibration ambiguity for dates around 2400 BP. It is also necessary to correct for the marine reservoir effect on 14 C ages of human bone samples from people who consumed marine food as a protein source. The Ohtomo site in western Japan, is a cemetery site used from the end of the Latest Jomon period to the Kofun period, provide a useful archaeological chronology. Human bones found in dolmen burials, jar burials and cist burials. In this study, we determined the 14 C ages of human bone samples and calculated the marine reservoir effect, using diet analysis based on carbon and nitrogen stable isotopes. Diet analysis showed that these people obtained from 40% to 60% of their protein from marine sources. Their 14 C ages with calibration and marine reservoir correction were serially matched with the archaeological chronology

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…

Physical activity, quality of life and medication in aging: differences between age and gender

Directory of Open Access Journals (Sweden)

Lilian Teresa Bucken Gobbi

2009-04-01

Full Text Available Studies have shown an inverse relationship between physical activity level (PAL, quality of life (QoL and use of medications in the elderly. The objective of this study was to analyze possible relationships and differences between PAL, QoL and use of medications in the elderly. A total of 192 subjects (≥ 60 years were selected by stratified random sampling according to census sector. The following assessment instruments were used: a Modified Baecke Questionnaire for older adults, b Medical Outcomes Study – 36-Item Short Form Health Survey, and c Sociodemographic and Health Factors Questionnaire. Descriptive statistics and parametric and nonparametric tests were used (p < 0.05. a With respect to chronological age, significant differences between groups were only observed for PAL, with G1 (60-69 years being more active than the other groups. b With respect to gender irrespective of age, analysis showed a difference in QoL and in the number of medications, with men reporting better perceived QoL and using fewer medications. c With respect to gender but considering chronological age, differences in PAL, QoL and medication use were observed between genders for specific age groups. In conclusion, in the elderly a PAL is low, declines even more during advanced age and is higher in men than in women during the first decade of old age, and b men report better perceived QoL and use fewer medications than women.

Calorie restriction extends the chronological lifespan of Saccharomyces cerevisiae independently of the Sirtuins.

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Smith, Daniel L; McClure, Julie M; Matecic, Mirela; Smith, Jeffrey S

2007-10-01

Calorie restriction (CR) extends the mean and maximum lifespan of a wide variety of organisms ranging from yeast to mammals, although the molecular mechanisms of action remain unclear. For the budding yeast Saccharomyces cerevisiae reducing glucose in the growth medium extends both the replicative and chronological lifespans (CLS). The conserved NAD(+)-dependent histone deacetylase, Sir2p, promotes replicative longevity in S. cerevisiae by suppressing recombination within the ribosomal DNA locus and has been proposed to mediate the effects of CR on aging. In this study, we investigated the functional relationships of the yeast Sirtuins (Sir2p, Hst1p, Hst2p, Hst3p and Hst4p) with CLS and CR. SIR2, HST2, and HST4 were not major regulators of CLS and were not required for the lifespan extension caused by shifting the glucose concentration from 2 to 0.5% (CR). Deleting HST1 or HST3 moderately shortened CLS, but did not prevent CR from extending lifespan. CR therefore works through a Sirtuin-independent mechanism in the chronological aging system. We also show that low temperature or high osmolarity additively extends CLS when combined with CR, suggesting that these stresses and CR act through separate pathways. The CR effect on CLS was not specific to glucose. Restricting other simple sugars such as galactose or fructose also extended lifespan. Importantly, growth on nonfermentable carbon sources that force yeast to exclusively utilize respiration extended lifespan at nonrestricted concentrations and provided no additional benefit when restricted, suggesting that elevated respiration capacity is an important determinant of chronological longevity.

A chronology of hurricane landfalls at Little Sippewissett Marsh, Massachusetts, USA, using optical dating

Science.gov (United States)

Madsen, A. T.; Duller, G. A. T.; Donnelly, J. P.; Roberts, H. M.; Wintle, A. G.

2009-08-01

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 within a sediment core from the salt-marsh. Variability in the luminescence characteristics between aliquots was observed and ~ 33% of the measured aliquots were discarded based upon the ratio of the fast component to the medium component. The majority of the samples gave normal dose distributions implying homogeneous resetting of the luminescence signal at the time of deposition, but three of the samples required application of the minimum age model (MAM). Ages ranging between 20 ± 2 and 594 ± 38 years were obtained and are broadly in agreement with independent chronologies, thus demonstrating the potential of optical dating in this setting. The hurricane record based upon optical dating extends approximately 300 years further back in time than the official National Oceanic Atmospheric Administration (NOAA) record. The localised nature of hurricane landfalls means that it will be necessary to collect multiple cores from a number of different sites in order to build up a complete hurricane record for this part of the coast.

Age versus schooling effects on intelligence development.

Science.gov (United States)

Cahan, S; Cohen, N

1989-10-01

The effect of formal education, as opposed to chronological age, on intelligence development has suffered from inadequate empirical investigation. Most studies of this issue have relied on natural variation in exposure to school among children of the same age, thus confounding differences in schooling with differences in other intelligence-related variables. This difficulty can be overcome by a quasi-experimental paradigm involving comparison between children who differ in both chronological age and schooling. The present study applies this paradigm to the estimation of the independent effects of age and schooling in grades 5 and 6 on raw scores obtained on a variety of general ability tests. The sample included all students in Jerusalem's Hebrew-language, state-controlled elementary schools. The results unambiguously point to schooling as the major factor underlying the increase of intelligence test scores as a function of age and to the larger effect schooling has on verbal than nonverbal tests. These results contribute to our understanding of the causal model underlying intelligence development and call for reconsideration of the conceptual basis underlying the definition of deviation-IQ scores. Some implications of these results concerning the distinction between intelligence and scholastic achievement, the causal model underlying the development of "crystallized" and "fluid" abilities, and the notion of "culture-fair" tests are discussed.

The Plio-Quaternary Volcanic Evolution of Gran Canaria Based on new Unspiked K-Ar ages and Magnetostratigraphy

Science.gov (United States)

Guillou, H.; Carracedo, J.; Perez Torrado, F.

2003-12-01

The combined use of radioisotopic dating, magnetostratigraphy and field geology is a powerful tool to provide reliable chronological frameworks of volcanic edifices. This approach has been used to investigate the last two stages of the volcanic evolution of Gran Canaria. Fifty samples were dated using the unspiked K-Ar method and had their magnetic polarity measured both in the field and in laboratory. Ages were compared to their stratigraphic positions and magnetic polarities before accepting their validity. The unspiked K-Ar chronology constrains the timing of lateral collapses, eruption rates and the contemporaneity of different volcano-magmatic stages at Gran Canaria. Our new data set modifies significantly the previous chronological framework of Gran Canaria, especially between 4 and 2.8 Ma. Based on these new ages, we can bracket the age of the multiple lateral collapses of the Roque Nublo stratovolcano flanks between 3.5 and 3.1 Ma .This time interval corresponds to a main period of volcanic quiescence. Calculated eruptive rates during the stratovolcano edification are about 0.1 km3/kyr which is significantly lower than the published estimates. The dating also reveals that the two main last stages are not separated by a major time gap, but that the early stages of the rift forming eruption and the vanishing activity of the Roque Nublo strato-volcano were contemporaneous for at least 600 kyrs. These results support that our combined approach provides a rapid first-pass and reliable geochronology. Nevertheless, this chronology can be amplified and made more precise where necessary through detailed Ar-Ar incremental-heating methods. Samples which should be investigated using this method are the oldest and youngest K-Ar dated flows of each volcanic stage, and samples from stratigraphic sections that hold potential to study the behaviour of the earth's magnetic field during reversals (Gauss-Gilbert transition, Olduvai and Reunion events).

DNA methylation age is elevated in breast tissue of healthy women.

Science.gov (United States)

Sehl, Mary E; Henry, Jill E; Storniolo, Anna Maria; Ganz, Patricia A; Horvath, Steve

2017-07-01

Limited evidence suggests that female breast tissue ages faster than other parts of the body according to an epigenetic biomarker of aging known as the "epigenetic clock." However, it is unknown whether breast tissue samples from healthy women show a similar accelerated aging effect relative to other tissues, and what could drive this acceleration. The goal of this study is to validate our initial finding of advanced DNA methylation (DNAm) age in breast tissue, by directly comparing it to that of peripheral blood tissue from the same individuals, and to do a preliminary assessment of hormonal factors that could explain the difference. We utilized n = 80 breast and 80 matching blood tissue samples collected from 40 healthy female participants of the Susan G. Komen Tissue Bank at the Indiana University Simon Cancer Center who donated these samples at two time points spaced at least a year apart. DNA methylation levels (Illumina 450K platform) were used to estimate the DNAm age. DNAm age was highly correlated with chronological age in both peripheral blood (r = 0.94, p < 0.0001) and breast tissues (r = 0.86, p < 0.0001). A measure of epigenetic age acceleration (age-adjusted DNAm Age) was substantially increased in breast relative to peripheral blood tissue (p = 1.6 × 10 -11 ). The difference between DNAm age of breast and blood decreased with advancing chronologic age (r = -0.53, p = 4.4 × 10 -4 ). Our data clearly demonstrate that female breast tissue has a higher epigenetic age than blood collected from the same subject. We also observe that the degree of elevation in breast diminishes with advancing age. Future larger studies will be needed to examine associations between epigenetic age acceleration and cumulative hormone exposure.

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.

Computer-assisted analysis of cervical vertebral bone age using cephalometric radiographs in Brazilian subjects

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Maria de Paula Caldas

2010-03-01

Full Text Available The aims of this study were to develop a computerized program for objectively evaluating skeletal maturation on cephalometric radiographs, and to apply the new method to Brazilian subjects. The samples were taken from the patient files of Oral Radiological Clinics from the North, Northeast, Midwest and South regions of the country. A total of 717 subjects aged 7.0 to 15.9 years who had lateral cephalometric radiographs and hand-wrist radiographs were selected. A cervical vertebral computerized analysis was created in the Radiocef Studio 2 computer software for digital cephalometric analysis, and cervical vertebral bone age was calculated using the formulas developed by Caldas et al.17 (2007. Hand-wrist bone age was evaluated by the TW3 method. Analysis of variance (ANOVA and the Tukey test were used to compare cervical vertebral bone age, hand-wrist bone age and chronological age (P < 0.05. No significant difference was found between cervical vertebral bone age and chronological age in all regions studied. When analyzing bone age, it was possible to observe a statistically significant difference between cervical vertebral bone age and hand-wrist bone age for female and male subjects in the North and Northeast regions, as well as for male subjects in the Midwest region. No significant difference was observed between bone age and chronological age in all regions except for male subjects in the North and female subjects in the Northeast. Using cervical vertebral bone age, it might be possible to evaluate skeletal maturation in an objective manner using cephalometric radiographs.

Comparing records with related chronologies

Science.gov (United States)

Bronk Ramsey, Christopher; Albert, Paul; Kearney, Rebecca; Staff, Richard A.

2016-04-01

In order to integrate ice, terrestrial and marine records, it is necessary to deal with records on different timescales. These timescales can be grouped into those that use a common fundamental chronometer (such as Uranium-Thorium dating or Radiocarbon) and can also be related to one another where we have chronological tie points such as tephra horizons. More generally we can, through a number of different methodologies, derive relationships between different timescales. A good example of this is the use of cosmogenic isotope production, specifically 10Be and 14C to relate the calibrated radiocarbon timescale to that of the Greenland ice cores. The relationships between different timescales can be mathematically expressed in terms of time-transfer functions. This formalism allows any related record to be considered against any linked timescale with an appropriate associated uncertainty. The prototype INTIMATE chronological database allows records to be viewed and compared in this way and this is now being further developed, both to include a wider range of records and also to provide better connectivity to other databases and chronological tools. These developments will also include new ways to use tephra tie-points to constrain the relationship between timescales directly, without needing to remodel each associated timescale. The database as it stands allows data for particular timeframes to be recalled and plotted against any timescale, or exported in spreadsheet format. New functionality will be added to allow users to work with their own data in a private space and then to publish it when it has been through the peer-review publication process. In order to make the data easier to use for other further analysis and plotting, and with data from other sources, the database will also act as a server to deliver data in a JSON format. The aim of this work is to make the comparison of integrated data much easier for researchers and to ensure that good practice in

Correlating Ice Cores from Quelccaya Ice Cap with Chronology from Little Ice Age Glacial Extents

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Stroup, J. S.; Kelly, M. A.; Lowell, T. V.

2010-12-01

Proxy records indicate Southern Hemisphere climatic changes during the Little Ice Age (LIA; ~1300-1850 AD). In particular, records of change in and around the tropical latitudes require attention because these areas are sensitive to climatic change and record the dynamic interplay between hemispheres (Oerlemans, 2005). Despite this significance, relatively few records exist for the southern tropics. Here we present a reconstruction of glacial fluctuations of Quelccaya Ice Cap (QIC), Peruvian Andes, from pre-LIA up to the present day. In the Qori Kalis valley, extensive sets of moraines exist beginning with the 1963 AD ice margin (Thompson et al., 2006) and getting progressively older down valley. Several of these older moraines can be traced and are continuous with moraines in the Challpa Cocha valley. These moraines have been dated at chronology of past ice cap extents are correlated with ice core records from QIC which show an accumulation increase during ~1500-1700 AD and an accumulation decrease during ~1720-1860 AD (Thompson et al., 1985; 1986; 2006). In addition, other proxy records from Peru and the tropics are correlated with the records at QIC as a means to understand climate conditions during the LIA. This work forms the basis for future modeling of the glacial system during the LIA at QIC and for modeling of past temperature and precipitation regimes at high altitude in the tropics.

CLINICAL STUDY OF THE CHRONOLOGICAL CHANGES IN KNEE ALIGNMENT PATTERN IN NORMAL SOUTH-EAST NIGERIAN CHILDREN AGED BETWEEN 0 AND 5 YEARS

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Ezeuko V.C

2010-01-01

Full Text Available The purpose of this study is to establish the chronological changes in knee alignment pattern in normal South-East Nigerian children aged between 0 and 5 years. A total number of 1450 subjects (680 males and 770 females were used for the study. The intercondylar/intermalleolar distances were measured using a vernier caliper with the subjects standing erect in anatomical position to determine straight knee, genu valgum and genu varum. The data was analysed with Microsoft Excel version 2007. The prevalence was presented as percentage (%.The result showed that the subjects have varum by the first year of life, prevalently genu valgum in type by the second year, valgum by the third year, neutral by the fourth and fifth year.

Exercise, physiological function, and the selection of participants for aging research.

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Lazarus, Norman R; Harridge, Stephen D R

2010-08-01

Regular and vigorous exercisers appear to be the logical choice for studying the inherent aging process as they are essentially free from the complications of disuse. Cross-sectional studies of aging tend to depict an essentially smooth and progressive decrement of physiological function with increasing chronological age. On closer examination of such data, it is seen that although the young have high functional values and the very old low, between these limits, values are widely scattered. We have reevaluated published data from a meta-analysis of 242 studies on men and from a similar study on women. From both data sets, where VO2max was plotted against chronological age, we stratified the VO2max values into bandwidth intervals of 5 ml/kg/minute and then allocated data points to their respective bandwidth irrespective of chronological age. When replotted into bandwidths of functional equivalence, these data show that at the extremes of function, the young are separated from the old. Between these values, each functional bandwidth accommodates a wide age range. The decrement in function with chronological age is not smooth or well defined. We suggest that participants for research into healthy aging should be initially segregated into bands of functionally equivalent VO2max values irrespective of their chronological age. Subsequently, other physiological measurements should be made on every participant in the band in order to begin to define the physiological profile of the participants. By conducting longitudinal studies on every individual, it will be possible to chart the physiological history of each participant through various ages. Segregating participants into cohorts of functional equivalence with data handling blinded to chronological age may be of great utility in increasing our understanding of the inherent aging process.

Remote sensing data with the conditional latin hypercube sampling and geostatistical approach to delineate landscape changes induced by large chronological physical disturbances.

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Lin, Yu-Pin; Chu, Hone-Jay; Wang, Cheng-Long; Yu, Hsiao-Hsuan; Wang, Yung-Chieh

2009-01-01

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.

Poor postdischarge head growth is related to a 10% lower intelligence quotient in very preterm infants at the chronological age of five years.

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Neubauer, Vera; Fuchs, Teresa; Griesmaier, Elke; Kager, Katrin; Pupp-Peglow, Ulrike; Kiechl-Kohlendorfer, Ursula

2016-05-01

This study examined the relationship between head growth and cognitive outcome at the age of five years in preterm infants born at less than 32 weeks of gestation from 2003 to 2009, as previous research has mostly focused on outcomes in toddlers. The head circumference of 273 very preterm infants born in Tyrol, Austria, was measured at birth, discharge, the corrected ages of three, 12 and 24 months and the chronological age of five years. Suboptimal head size was defined as a head circumference of more than one standard deviation below the mean. Full-scale intelligence quotient (IQ) at five years was determined using Wechsler Preschool and Primary Scales of Intelligence, third edition. Infants with a suboptimal head size at the age of three months had a significantly lower median IQ than those with a normal head size (90 [20-122] versus 98 [20-138], p = 0.001) and from three months onwards they were more likely to exhibit cognitive delay. A suboptimal head size from the age of three months was consistently related to a 10% lower IQ, and this study adds further evidence that head growth failure, especially during the early postdischarge period, is related to impaired cognitive abilities. ©2016 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

Age-depth modelling with radiocarbon

International Nuclear Information System (INIS)

Howarth, J.D.

2017-01-01

Chronology is a critical component of any study into the Quaternary because the information about climate and environmental change preserved in sedimentary deposits can only be placed in a useful context when it is associated with a robust chronological framework. This overview will introduce you to the key concepts in age depth modelling.

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

Science.gov (United States)

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

2014-07-15

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

The last glacial cycle documented on the Lower Bengal Fan - chronological and paleoclimate implications

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Weber, M. E.; Dekens, P.; Reilly, B.; Lantzsch, H.; Selkin, P. A.; Das, S. K.; Williams, T.; Martos, Y. M.; Adhikari, R. R.; Gyawali, B. R.; Jia, G.; Fox, L. R.; Ge, J.; Manoj, M. C.; Savian, J. F.; Meynadier, L.; Spiess, V.; France-Lanord, C.; Klaus, A.

2016-12-01

IODP Expedition 354 set out in February to March 2015 to drill seven sites along an east west oriented core transect of 320 km length at 8°N in the Bengal Fan (France-Lanord et al., 2015). Sediments show complex intercalation of turbiditic and hemipelagic deposits, documenting the interaction of fan evolution and paleoceanographic history. Hemipelagic sequences represent a several meter thick top layer of Late Quaternary sediment. Deposits are either rich in biogenic opal/clay or in carbonate. We studied physical, optical, geochemical, grain-size, and stable isotopic properties of this top layer to establish a time frame, estimate sedimentary properties, and assess the development of the region during the last glacial cycle. For this purpose, we sampled Site U1452C-1H continuously for the uppermost 480 cm in 2-cm increments. Preliminary results indicate the Toba Ash 1 (74 ka) is a distinct time marker in most physical property data sets. Records of wet-bulk density as well as color reflectance b* (the red-green component) and L* (the lightness) show a dominant precession cyclicity. Hence, we are able to provide an insolation-tuned chronology for the last 200 ka (MIS1 - 7). These records agree well with d18O records retrieved from Chinese caves. An independent age model is derived from records of relative paleointensity (RPI), including the assessment of the Laschamp Event ( 40 ka), and on RPI tuning to global templates. We will compare both chronologies and evaluate their chronological and paleoclimatic implications. We will also present preliminary grain-size and paleoceanographic proxy data (sea-surface temperature, sea-surface salinity, and Mg/Ca) as well as color endmember modeling to reconstruct ice volume, marine biological productivity, nutrient supply, and deep-water circulation. The sedimentologic, oceanographic and climatic conditions are linked to changes in monsoonal strength and terrestrial input, which will also be studied using sedimentary proxies

Jewish Holocaust Histories and the Work of Chronological Narratives

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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…

Physical activity, quality of life and medication in aging: differences between age and gender

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Émerson Sebastião

2009-01-01

Full Text Available http://dx.doi.org/10.5007/1980-0037.2009v11n2p210   Studies have shown an inverse relationship between physical activity level (PAL, quality of life (QoL and use of medications in the elderly. The objective of this study was to analyze possible relationships and differences between PAL, QoL and use of medications in the elderly. A total of 192 subjects (≥ 60 years were selected by stratified random sampling according to census sector. The following assessment instruments were used: a Modified Baecke Questionnaire for older adults, b Medical Outcomes Study – 36-Item Short Form Health Survey, and c Sociodemographic and Health Factors Questionnaire. Descriptive statistics and parametric and nonparametric tests were used (p < 0.05. a With respect to chronological age, significant differences between groups were only observed for PAL, with G1 (60-69 years being more active than the other groups. b With respect to gender irrespective of age, analysis showed a difference in QoL and in the number of medications, with men reporting better perceived QoL and using fewer medications. c With respect to gender but considering chronological age, differences in PAL, QoL and medication use were observed between genders for specific age groups. In conclusion, in the elderly a PAL is low, declines even more during advanced age and is higher in men than in women during the first decade of old age, and b men report better perceived QoL and use fewer medications than women.

Two-dimensional chronostratigraphic modelling of OSL ages from recent beach-ridge deposits, SE Australia

DEFF Research Database (Denmark)

Tamura, Toru; Cunningham, Alastair C.; Oliver, Thomas S.N.

2018-01-01

Optically-stimulated luminesecne (OSL) dating, in concert with two-dimensional ground-penetrating radar (GPR) profiling, has contributed to significant advances in our understanding of beach-ridge systems and other sedimentary landforms in various settings. For recent beach-ridges, the good OSL...... samples may be larger than the difference in sample ages. Age inversions can be avoided, however, if the stratigraphic constraints are included in the age estimation process. Here, we create a custom Bayesian chronological model for a recent (..., for direct comparison with a GPR profile. The model includes a full ‘burial-dose model’ for each sample and a dose rate term with the modelled ages constrained by the vertical and shore-normal sample order. The modelled ages are visualized by plotting isochrones on the beach-ridge cross section...

Revisiting the loess/palaeosol sequence in Paks, Hungary: A post-IR IRSL based chronology for the ‘Young Loess Series’

DEFF Research Database (Denmark)

Thiel, Christine; Horváth, Erzsébet; Frechen, Manfred

2014-01-01

chronology reveals that most of the Late Pleistocene loess was deposited during marine isotope stage (MIS) 3 and during the Last Glacial Maximum (LGM). This is in disagreement with formerly published ages. The discrepancy can most likely be explained by anomalous fading (resulting in an age underestimate...

Developing a postglacial rockfall chronology in the mountainous fjord landscape of western Norway

Science.gov (United States)

Laute, Katja; Beylich, Achim A.; Winkler, Stefan

2015-04-01

Large areas of glacially sculpted mountain landscapes worldwide exhibit a high spatial density of postglacial rockfalls and rock-slope failures. However, the temporal patterns of rock-slope failure frequencies after Deglaciation are still fairly unknown. The mountainous fjord landscape in western Norway represents a suitable study area as it exhibits a high number of rockfalls and rock-slope failures within a region with a well known Deglaciation history. Two steep, parabolic-shaped and glacier-connected neighbouring drainage basins, Erdalen (79.5 km2) and Bødalen (60.1 km2), located on the western side of the Jostedalsbreen ice cap in western Norway are selected as study areas. The focus of this study is on (i) the temporal reconstruction of rockfalls and rock-slope failures within the two defined and nearly lithologically homogenous study areas and (ii) the identification and explanation of possible triggering and controlling factors of the investigated rock-slope failures. First investigations have started by applying Schmidt-hammer exposure-age dating (SHD) at seven larger rockfall deposits as well as at five moraines of known age within both study areas. During the sampling 50 to 100 impacts using a mechanical Proceq N-type instrument were taken from the surface of 5 to 50 single rockfall boulders located at the outer margin of the rockfall deposits. In order to avoid sampling of more recent rockfalls or redistributed debris material the sampling strategy selected preferred a larger number of individual boulders sampled with few impacts over sampling just a small number of boulders with a high number of multiple impacts. First results show that the mean rebound (R-) values measured at the seven rockfall deposits fall into recognizably different age categories. Based on the SHD measurements obtained from the moraines of known age, the determined rockfall age categories are situated between the Preboral and Little Ice Age period. The chronology and possible

Radiocarbon and optically stimulated luminescence dating based chronology of a polycyclic driftsand sequence at Weerterbergen (SE Netherlands)

NARCIS (Netherlands)

van Mourik, J.M.; Nierop, K.G.J.; Vandenberghe, D.A.G.

2010-01-01

The chronology of polycyclic driftsand sequences in cultural landscapes has mainly been based on the combination of radiocarbon (14C) dating of intercalated organic horizons and pollen analysis. This approach, however, yields indirect age information for the sediment units. Also, as soils are

Chronological evidence fails to support claim of an isochronous widespread layer of cosmic impact indicators dated to 12,800 years ago

Science.gov (United States)

Meltzer, David J.; Holliday, Vance T.; Cannon, Michael D.; Miller, D. Shane

2014-05-01

According to the Younger Dryas Impact Hypothesis (YDIH), ∼12,800 calendar years before present, North America experienced an extraterrestrial impact that triggered the Younger Dryas and devastated human populations and biotic communities on this continent and elsewhere. This supposed event is reportedly marked by multiple impact indicators, but critics have challenged this evidence, and considerable controversy now surrounds the YDIH. Proponents of the YDIH state that a key test of the hypothesis is whether those indicators are isochronous and securely dated to the Younger Dryas onset. They are not. We have examined the age basis of the supposed Younger Dryas boundary layer at the 29 sites and regions in North and South America, Europe, and the Middle East in which proponents report its occurrence. Several of the sites lack any age control, others have radiometric ages that are chronologically irrelevant, nearly a dozen have ages inferred by statistically and chronologically flawed age-depth interpolations, and in several the ages directly on the supposed impact layer are older or younger than ∼12,800 calendar years ago. Only 3 of the 29 sites fall within the temporal window of the YD onset as defined by YDIH proponents. The YDIH fails the critical chronological test of an isochronous event at the YD onset, which, coupled with the many published concerns about the extraterrestrial origin of the purported impact markers, renders the YDIH unsupported. There is no reason or compelling evidence to accept the claim that a cosmic impact occurred ∼12,800 y ago and caused the Younger Dryas.

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

Science.gov (United States)

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

2009-04-01

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

History of Science in the United States: A Chronology and Research Guide, by Clark A. Elliott, Garland Reference Library of the Humanities Vol. 1711, Garland Publishing, New York. 1996

Directory of Open Access Journals (Sweden)

Andrew L. Christenson

1996-11-01

Full Text Available There are four parts to this volume - a chronology of events by year, a chronology of leading scientists grouped by the decade in which they reached 25 years of age? a research guide, and a research bibliography. The author has written extensively on American science, including co-editing the volume Science at Harvard University (reviewed in BHA 2(1:17-19. The volume covers mostly what are termed the "hard" sciences (-.e., chemistry. biology, geology, etc. and touches upon the social sciences only rarely. The chronology. that takes up two thirds of the book, extends from ca. 1493 to 1990 and includes only three archaeological events. An example of these entries follows: "1877. ARCHAEOLOGY Ephraim George Squier (1821-1888 published Peru: Incidents of Travel and Exploration in the Land of the Incas (New York and London. Herelated his discovery of Latin American civilizations that predated the Inca. (p. 114" The scientist cohorts by decade also focuses upon the hard sciences, although three men are singled out from archaeology F. W. Putnam, N. H. Winchell, and T. M. Prodden - a peculiar sample of American archae­ologists indeed!

Chronology of Eocene-Miocene sequences on the New Jersey shallow shelf: implications for regional, interregional, and global correlations

Science.gov (United States)

Browning, James V.; Miller, Kenneth G.; Sugarman, Peter J.; Barron, John; McCarthy, Francine M.G.; Kulhanek, Denise K.; Katz, Miriam E.; Feigenson, Mark D.

2013-01-01

Integrated Ocean Drilling Program Expedition 313 continuously cored and logged latest Eocene to early-middle Miocene sequences at three sites (M27, M28, and M29) on the inner-middle continental shelf offshore New Jersey, providing an opportunity to evaluate the ages, global correlations, and significance of sequence boundaries. We provide a chronology for these sequences using integrated strontium isotopic stratigraphy and biostratigraphy (primarily calcareous nannoplankton, diatoms, and dinocysts [dinoflagellate cysts]). Despite challenges posed by shallow-water sediments, age resolution is typically ±0.5 m.y. and in many sequences is as good as ±0.25 m.y. Three Oligocene sequences were sampled at Site M27 on sequence bottomsets. Fifteen early to early-middle Miocene sequences were dated at Sites M27, M28, and M29 across clinothems in topsets, foresets (where the sequences are thickest), and bottomsets. A few sequences have coarse (∼1 m.y.) or little age constraint due to barren zones; we constrain the age estimates of these less well dated sequences by applying the principle of superposition, i.e., sediments above sequence boundaries in any site are younger than the sediments below the sequence boundaries at other sites. Our age control provides constraints on the timing of deposition in the clinothem; sequences on the topsets are generally the youngest in the clinothem, whereas the bottomsets generally are the oldest. The greatest amount of time is represented on foresets, although we have no evidence for a correlative conformity. Our chronology provides a baseline for regional and interregional correlations and sea-level reconstructions: (1) we correlate a major increase in sedimentation rate precisely with the timing of the middle Miocene climate changes associated with the development of a permanent East Antarctic Ice Sheet; and (2) the timing of sequence boundaries matches the deep-sea oxygen isotopic record, implicating glacioeustasy as a major driver

Bayesian chronological analyses consistent with synchronous age of 12,835–12,735 Cal B.P. for Younger Dryas boundary on four continents

Science.gov (United States)

Kennett, James P.; Kennett, Douglas J.; Culleton, Brendan J.; Aura Tortosa, J. Emili; Bischoff, James L.; Bunch, Ted E.; Daniel, I. Randolph; Erlandson, Jon M.; Ferraro, David; Firestone, Richard B.; Goodyear, Albert C.; Israde-Alcántara, Isabel; Johnson, John R.; Jordá Pardo, Jesús F.; Kimbel, David R.; LeCompte, Malcolm A.; Lopinot, Neal H.; Mahaney, William C.; Moore, Andrew M. T.; Moore, Christopher R.; Ray, Jack H.; Stafford, Thomas W.; Tankersley, Kenneth Barnett; Wittke, James H.; Wolbach, Wendy S.; West, Allen

2015-01-01

The Younger Dryas impact hypothesis posits that a cosmic impact across much of the Northern Hemisphere deposited the Younger Dryas boundary (YDB) layer, containing peak abundances in a variable assemblage of proxies, including magnetic and glassy impact-related spherules, high-temperature minerals and melt glass, nanodiamonds, carbon spherules, aciniform carbon, platinum, and osmium. Bayesian chronological modeling was applied to 354 dates from 23 stratigraphic sections in 12 countries on four continents to establish a modeled YDB age range for this event of 12,835–12,735 Cal B.P. at 95% probability. This range overlaps that of a peak in extraterrestrial platinum in the Greenland Ice Sheet and of the earliest age of the Younger Dryas climate episode in six proxy records, suggesting a causal connection between the YDB impact event and the Younger Dryas. Two statistical tests indicate that both modeled and unmodeled ages in the 30 records are consistent with synchronous deposition of the YDB layer within the limits of dating uncertainty (∼100 y). The widespread distribution of the YDB layer suggests that it may serve as a datum layer. PMID:26216981

Characterizing Facial Skin Ageing in Humans: Disentangling Extrinsic from Intrinsic Biological Phenomena

Science.gov (United States)

Trojahn, Carina; Dobos, Gabor; Lichterfeld, Andrea; Blume-Peytavi, Ulrike; Kottner, Jan

2015-01-01

Facial skin ageing is caused by intrinsic and extrinsic mechanisms. Intrinsic ageing is highly related to chronological age. Age related skin changes can be measured using clinical and biophysical methods. The aim of this study was to evaluate whether and how clinical characteristics and biophysical parameters are associated with each other with and without adjustment for chronological age. Twenty-four female subjects of three age groups were enrolled. Clinical assessments (global facial skin ageing, wrinkling, and sagging), and biophysical measurements (roughness, colour, skin elasticity, and barrier function) were conducted at both upper cheeks. Pearson's correlations and linear regression models adjusted for age were calculated. Most of the measured parameters were correlated with chronological age (e.g., association with wrinkle score, r = 0.901) and with each other (e.g., residual skin deformation and wrinkle score, r = 0.606). After statistical adjustment for age, only few associations remained (e.g., mean roughness (R z) and luminance (L *),  β = −0.507, R 2 = 0.377). Chronological age as surrogate marker for intrinsic ageing has the most important influence on most facial skin ageing signs. Changes in skin elasticity, wrinkling, sagging, and yellowness seem to be caused by additional extrinsic ageing. PMID:25767806

Characterizing Facial Skin Ageing in Humans: Disentangling Extrinsic from Intrinsic Biological Phenomena

Directory of Open Access Journals (Sweden)

Carina Trojahn

2015-01-01

Full Text Available Facial skin ageing is caused by intrinsic and extrinsic mechanisms. Intrinsic ageing is highly related to chronological age. Age related skin changes can be measured using clinical and biophysical methods. The aim of this study was to evaluate whether and how clinical characteristics and biophysical parameters are associated with each other with and without adjustment for chronological age. Twenty-four female subjects of three age groups were enrolled. Clinical assessments (global facial skin ageing, wrinkling, and sagging, and biophysical measurements (roughness, colour, skin elasticity, and barrier function were conducted at both upper cheeks. Pearson’s correlations and linear regression models adjusted for age were calculated. Most of the measured parameters were correlated with chronological age (e.g., association with wrinkle score, r=0.901 and with each other (e.g., residual skin deformation and wrinkle score, r=0.606. After statistical adjustment for age, only few associations remained (e.g., mean roughness (Rz and luminance (L*,  β=-0.507, R2=0.377. Chronological age as surrogate marker for intrinsic ageing has the most important influence on most facial skin ageing signs. Changes in skin elasticity, wrinkling, sagging, and yellowness seem to be caused by additional extrinsic ageing.

Iron Age Mediterranean Chronology : A Reply

NARCIS (Netherlands)

Bruins, Hendrik J.; Nijboer, Albert J.; van der Plicht, Johannes

2011-01-01

This article is a reply to the preceding rejoinder by Fantalkin et al., which they wrote in response to our article concerning radiocarbon dates of Iron Age sites in the Mediterranean region measured at Groningen (van der Plicht et al. 2009). We do not agree with much of their criticism. Our reply

Mitochondrial Respiratory Thresholds Regulate Yeast Chronological Lifespan and its Extension by Caloric Restriction

OpenAIRE

Ocampo, Alejandro; Liu, Jingjing; Schroeder, Elizabeth A.; Shadel, Gerald S.; Barrientos, Antoni

2012-01-01

We have explored the role of mitochondrial function in aging by genetically and pharmacologically modifying yeast cellular respiration production during the exponential and/or stationary growth phases, and determining how this affects chronological lifespan (CLS). Our results demonstrate that respiration is essential during both growth phases for standard CLS, but that yeast have a large respiratory capacity and only deficiencies below a threshold (~40% of wild-type) significantly curtail CLS...

Climatic events and Upper Paleolithic chronology in the Dniester basin : New C-14 results from Cosautsi

NARCIS (Netherlands)

Haesaerts, P; Borziak, [No Value; Van Der Plicht, J; Damblon, F; Borziak, Ilic; Mook, W.G.

1998-01-01

We discuss the radiocarbon chronology of the loess deposited during the Upper Pleniglacial (Isotope Stage II) for the key site of Cosautsi (Republic of Moldova), which presents some major problems in C-14 dating. Special care was paid to accurate microstratigraphic positioning of samples, collection

On the palaeoclimatic potential of a millennium-long oak ring width chronology from Slovakia

Czech Academy of Sciences Publication Activity Database

Prokop, O.; Kolář, Tomáš; Büntgen, Ulf; Kyncl, J.; Bošela, M.; Choma, M.; Barta, P.; Rybníček, Michal

2016-01-01

Roč. 40, DEC (2016), s. 93-101 ISSN 1125-7865 R&D Projects: GA MŠk(CZ) LO1415; GA ČR GA13-04291S Institutional support: RVO:67179843 Keywords : Composite tree-ring chronology * European oak * Palaeoclimatology * Random update sampling * Ring width * Slovakia Subject RIV: EH - Ecology, Behaviour Impact factor: 2.259, year: 2016

Chronology of the early period of the Ananyino cultural and historical area

Directory of Open Access Journals (Sweden)

Kuzminykh Sergei V.

2014-09-01

Full Text Available Problems related to the chronology of the early period in the Ananyino cultural and historical area development are discussed in the article. The chronology is based upon the objects imported from the Black Sea region, Northern Caucasus and Transcaucasia and their Ananyino replicas or imitations. Radiocarbon dates have also been taken into account. The period under consideration is divided into two stages (I-1 and I-2. They are characterized by differing technological facilities that had determined the appearance of a differing set of material culture objects. The first stage, the transition from the Bronze Age to the Early Iron Age, is dated within the 9th to mid-8th century BC. The second phase (mid-8th to first quarter/first half of the 7th century BC is associated with the spread of Caucasian imports in the Volga-Kama area and mostly in the post-Maklasheevka culture sites. On the basis of these imports it is possible to claim that the Ananyino area was included into the international trade and exchange system of Eastern Europe, the Caucasus and Transcaucasia. Monuments of the early period of the Ananyino cultural and historical area are primarily synchronized with the pre-Scythian funeral monuments of the steppe zone of Eastern Europe and the Caucasus.

Environmental and lifestyle factors associated with perceived facial age in Chinese women.

Directory of Open Access Journals (Sweden)

Andrew E Mayes

Full Text Available Perceived facial age has been proposed as a biomarker of ageing with 'looking young for one's age' linked to physical and cognitive functioning and to increased survival for Caucasians. We have investigated the environmental and lifestyle factors associated with perceived facial ageing in Chinese women. Facial photographs were collected from 250 Chinese women, aged 25-70 years in Shanghai, China. Perceived facial age was determined and related to chronological age for each participant. Lifestyle and health information was collected by questionnaire. Bivariate analyses (controlling for chronological age identified and quantified lifestyle variables associated with perceived facial age. Independent predictors of perceived age were identified by multivariate modelling. Factors which significantly associated with looking younger for one's chronological age included greater years of education (p<0.001, fewer household members (p=0.027, menopausal status (p=0.020, frequency of visiting one's doctor (p=0.013, working indoors (p<0.001, spending less time in the sun (p=0.015, moderate levels of physical activity (p=0.004, higher frequency of teeth cleaning (p<0.001 and more frequent use of facial care products: cleanser (p<0.001; moisturiser (p=0.016 or night cream (p=0.016. Overall, 36.5% of the variation in the difference between perceived and chronological age could be explained by a combination of chronological age and 6 independent lifestyle variables. We have thus identified and quantified a number of factors associated with younger appearance in Chinese women. Presentation of these factors in the context of facial appearance could provide significant motivation for the adoption of a range of healthy behaviours at the level of both individuals and populations.

A radiographic study estimating age of mandibular third molars by periodontal ligament visibility.

Science.gov (United States)

Chaudhary, M A; Liversidge, H M

2017-12-01

Visibility of the periodontal ligament of mandibular third molars (M3) has been suggested as a method to estimate age. To assess the accuracy of this method and compare the visibility of the periodontal ligament in the left M3 with the right M3. The sample was archived panoramic dental radiographs of 163 individuals (75 males, 88 females, age 16-53 years) with mature M3's. Reliability was assessed using Kappa. Accuracy was assessed by subtracting chronological age from estimated age for males and females. Stages were cross-tabulated against age stages younger than and at least 18 and 21 years of age. Stages were compared in the left M3 and right M3. Analysis showed excellent intra-observer reliability. Mean difference between estimated and chronological ages was 7.21 years (SD 5.16) for left M3 and 7.69 (SD 6.08) for right M3 in males and 6.87 (SD 5.83) for left M3 and 8.61 (SD 6.58) for right M3 in females. Minimum ages of stages 0 to 2 were younger than previously reported, despite a small sample of individuals younger than 18. The left and right M3 stage differed in 46% of the 85 individuals with readings from both side and estimated age differed from -10.5 to 12.2 years between left and right. Accuracy of this method was between 6 and 8 years with an error of 5 to 6 years. The number of individuals with mature M3 apices younger than 18 years was small. The stage of visibility of the periodontal ligament differed between left and right in almost half of our sample with both teeth present. Our findings question the use of this method to estimate age or to discriminate between age younger and at least 18 years.

Tell es-Sultan (Jericho) : Radiocarbon results of short-lived cereal and multiyear charcoal samples from the end of the Middle Bronze Age

NARCIS (Netherlands)

Bruins, HJ; VanDerPlicht, J; Bruins, Hendrik J.; Cook, G.T.; Harkness, D.D.; Miller, B.F.; Scott, E.M.

1995-01-01

Samples from Tell es-Sultan, Jericho, were selected for high-precision C-14 dating as a contribution toward the establishment of an independent radiocarbon chronology of Near Eastern archaeology. The material derives from archaeological excavations conducted by K. M. Kenyon in the 1950s. We present

Applicability of Greulich and Pyle method for age assessment in forensic practice on an Italian sample.

Science.gov (United States)

Tisè, Marco; Mazzarini, Laura; Fabrizzi, Giancarlo; Ferrante, Luigi; Giorgetti, Raffaele; Tagliabracci, Adriano

2011-05-01

The main importance in age estimation lies in the assessment of criminal liability and protection of unaccompanied minor immigrants, when their age is unknown. Under Italian law, persons are not criminally responsible before they reach the age of 14. The age of 18 is important when deciding whether juvenile or adult law must be applied. In the case of unaccompanied minors, it is important to assess age in order to establish special protective measures, and correct age estimation may prevent a person over 18 from benefiting from measures reserved for minors. Since the Greulich and Pyle method is one of the most frequently used in age estimation, the aim of this study was to assess the reproducibility and accuracy of the method on a large Italian sample of teenagers, to ascertain the applicability of the Atlas at the critical age thresholds of 14 and 18 years. This retrospective study examined posteroanterior X-ray projections of hand and wrist from 484 Italian-Caucasian young people (125 females, 359 males) between 11 and 19 years old. All radiographic images were taken from trauma patients hospitalized in the Azienda Ospedaliero Universitaria Ospedali Riuniti of Ancona (Italy) between 2006 and 2007. Two physicians analyzed all radiographic images separately. The blind method was used. In the case of an estimated age of 14 years old, the true age ranged from 12.2 to 15.9 years (median, 14.3 years, interquartile range, 1.0 years) for males, and 12.6 to 15.7 years (median, 14.2 years, interquartile range, 1.7 years) for females. In the case of an estimated age of 18 years, the true age ranged from 15.6 to 19.7 years (median, 17.7 years, interquartile range, 1.4 years) for males, and from 16.2 to 20.0 years (median, 18.7 years, interquartile range, 1.8 years) for females. Our study shows that although the GPM is a reproducible and repeatable method, there is a wide margin of error in the estimation of chronological age, mainly in the critical estimated

Establishment of an absolute chronology for the 18th Egyptian Dynasty

International Nuclear Information System (INIS)

Quiles, A.

2011-01-01

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)

Accelerated DNA Methylation Age: Associations with PTSD and Neural Integrity

Science.gov (United States)

Wolf, Erika J.; Logue, Mark W.; Hayes, Jasmeet P.; Sadeh, Naomi; Schichman, Steven A.; Stone, Annjanette; Salat, David H.; Milberg, William; McGlinchey, Regina; Miller, Mark W.

2015-01-01

Background Accumulating evidence suggests that post traumatic stress disorder (PTSD) may accelerate cellular aging and lead to premature morbidity and neurocognitive decline. Methods This study evaluated associations between PTSD and DNA methylation (DNAm) age using recently developed algorithms of cellular age by Horvath (2013) and Hannum et al. (2013). These estimates reflect accelerated aging when they exceed chronological age. We also examined if accelerated cellular age manifested in degraded neural integrity, indexed via diffusion tensor imaging. Results Among 281 male and female veterans of the conflicts in Iraq and Afghanistan, DNAm age was strongly related to chronological age (rs ~.88). Lifetime PTSD severity was associated with Hannum DNAm age estimates residualized for chronological age (β = .13, p= .032). Advanced DNAm age was associated with reduced integrity in the genu of the corpus callosum (β = −.17, p= .009) and indirectly linked to poorer working memory performance via this region (indirect β = − .05, p= .029). Horvath DNAm age estimates were not associated with PTSD or neural integrity. Conclusions Results provide novel support for PTSD-related accelerated aging in DNAm and extend the evidence base of known DNAm age correlates to the domains of neural integrity and cognition. PMID:26447678

Mood disorders in eating disorder patients: Prevalence and chronology of ONSET.

Science.gov (United States)

Godart, N; Radon, L; Curt, F; Duclos, J; Perdereau, F; Lang, F; Venisse, J L; Halfon, O; Bizouard, P; Loas, G; Corcos, M; Jeammet, Ph; Flament, M F

2015-10-01

In a clinical population, we estimated the frequency of mood disorders among 271 patients suffering from Anorexia Nervosa (AN) and Bulimia Nervosa (BN) in comparison to a control group matched for age and gender. The frequency of mood disorders was measured using the Mini International Neuropsychiatric Interview (MINI), DSM-IV version. Mood disorders were more frequent among eating disorder (ED) patients than among controls, with a global prevalence of the order of 80% for each ED group. The majority of the mood disorders comorbid with ED were depressive disorders (MDD and dysthymia). The relative chronology of onset of these disorders was equivocal, because mood disorders in some cases preceded and in others followed the onset of the eating disorders. Our sample was characterized by patients with severe ED and high comorbidities, and thus do not represent the entire population of AN or BN. This also may have resulted in an overestimation of prevalence. Mood disorders appear significantly more frequently in patients seeking care for ED than in controls. These results have implications for the assessment and treatment of ED patients, and for the aetio-pathogenesis of these disorders. Copyright © 2015 Elsevier B.V. All rights reserved.

Environmental and Lifestyle Factors Associated with Perceived Facial Age in Chinese Women

Science.gov (United States)

Mayes, Andrew E.; Murray, Peter G.; Gunn, David A.; Tomlin, Cyrena C.; Catt, Sharon D.; Wen, Yi B.; Zhou, Li P.; Wang, Hong Q.; Catt, Michael; Granger, Stewart P.

2010-01-01

Perceived facial age has been proposed as a biomarker of ageing with ‘looking young for one’s age' linked to physical and cognitive functioning and to increased survival for Caucasians. We have investigated the environmental and lifestyle factors associated with perceived facial ageing in Chinese women. Facial photographs were collected from 250 Chinese women, aged 25–70 years in Shanghai, China. Perceived facial age was determined and related to chronological age for each participant. Lifestyle and health information was collected by questionnaire. Bivariate analyses (controlling for chronological age) identified and quantified lifestyle variables associated with perceived facial age. Independent predictors of perceived age were identified by multivariate modelling. Factors which significantly associated with looking younger for one's chronological age included greater years of education (p<0.001), fewer household members (p = 0.027), menopausal status (p = 0.020), frequency of visiting one's doctor (p = 0.013), working indoors (p<0.001), spending less time in the sun (p = 0.015), moderate levels of physical activity (p = 0.004), higher frequency of teeth cleaning (p<0.001) and more frequent use of facial care products: cleanser (p<0.001); moisturiser (p = 0.016) or night cream (p = 0.016). Overall, 36.5% of the variation in the difference between perceived and chronological age could be explained by a combination of chronological age and 6 independent lifestyle variables. We have thus identified and quantified a number of factors associated with younger appearance in Chinese women. Presentation of these factors in the context of facial appearance could provide significant motivation for the adoption of a range of healthy behaviours at the level of both individuals and populations. PMID:21179450

Ancient Egyptian chronology and the astronomical orientation of pyramids

Science.gov (United States)

Spence, Kate

2000-11-01

The ancient Egyptian pyramids at Giza have never been accurately dated, although we know that they were built approximately around the middle of the third millennium BC. The chronologies of this period have been reconstructed from surviving lists of kings and the lengths of their reigns, but the lists are rare, seldom complete and contain known inconsistencies and errors. As a result, the existing chronologies for that period (the Old Kingdom) can be considered accurate only to about +/-100 years, a figure that radiocarbon dating cannot at present improve. Here I use trends in the orientation of Old Kingdom pyramids to demonstrate that the Egyptians aligned them to north by using the simultaneous transit of two circumpolar stars. Modelling the precession of these stars yields a date for the start of construction of the Great Pyramid that is accurate to +/-5 yr, thereby providing an anchor for the Old Kingdom chronologies.

The EASTNET Project: Extending the Network of Climate-Sensitive Tree-Ring Chronologies From the Eastern United States for Reconstructing the Spatio-Temporal Characteristics of Climate and Drought Over the Past Millennium

Science.gov (United States)

Buckley, B. M.; Cook, E. R.

2002-12-01

Recently, a network of gridded PDSI reconstructions for the contiguous United States was produced, based on the available network of drought-sensitive tree-ring chronologies (Cook et al. 1999). Analyses were constrained to the common period of 1700 - 1979 due to the limitations of the available tree-ring data. While several chronologies from the western U.S. span 1,000 years or more, very few chronologies from the eastern U.S. covered even the past 500 years. The objective of this project, funded by the National Science Foundation's ESH program, is to extend the tree-ring chronology network from the eastern U.S. with chronologies spanning the past 500-1,000 years. This aim is being achieved by sampling in areas that have escaped the effects of development, logging and major disturbance such as fire. The two main target species are Thuja occidentalis (eastern white cedar) and Juniperus virginiana (eastern red cedar). The primary terrain types are on cliffs, rocky outcrops, and other areas that have been difficult to access. We have already developed chronologies from Wisconsin, New Hampshire, Pennsylvania, West Virginia, and Virginia that span from 500 to 1500 years. The temporal depth of these chronologies is being extended through the exploitation of "sub-fossil" wood found at these sites, in the form of standing-dead stems and downed and buried logs. We are also currently pursuing leads in Maine, Vermont, Massachusetts, Connecticut, New York, New Jersey Pennsylvania, Kentucky and North Carolina where old cedar trees have either been reported or where terrain types match criteria developed for this project. In this paper we discuss the current status of the network, and explore the spatio-temporal characteristics of climate and drought across the eastern US for the past 500 years and more. We use our preliminary network to explore the regional expression of climate anomalies such as drought. Our analyses so far demonstrates multicentennial variability suggestive

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 (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, proximal BIT-152 provides one such link. The New Mexico Geochronology Research Lab (NMGRL) has two new multi-collector ARGUS VI mass spectrometers that can provide single crystal laser fusion ages that are approximately an order of magnitude more precise than the previous determinations. With these advancements in analytical technology, we hope to improve precision on 'pinning points' in the deep ice cores where annual layer counting becomes less precise.

Age estimation by canines' pulp/tooth ratio in an Iranian population using digital panoramic radiography.

Science.gov (United States)

Dehghani, Mahdieh; Shadkam, Elaheh; Ahrari, Farzaneh; Dehghani, Mahboobe

2018-04-01

Age estimation in adults is an important issue in forensic science. This study aimed to estimate the chronological age of Iranians by means of pulp/tooth area ratio (AR) of canines in digital panoramic radiographs. The sample consisted of panoramic radiographs of 271 male and female subjects aged 16-64 years. The pulp/tooth area ratio (AR) of upper and lower canines was calculated by AutoCAD software. Data were subjected to correlation and regression analysis. There was a significant and inverse correlation between age and pulp/tooth area ratio of upper and lower canines (r=-0.794 for upper canine and r=-0.282 for lower canine; p-value<0.001). Linear regression equations were derived separately for upper, lower and both canines. The mean difference between actual and estimated age using upper canine was 6.07±1.7. The results showed that the pulp/tooth area ratios of canines are a reliable method for age estimation in Iranians. The pulp/tooth area ratio of upper canine was better correlated with chronological age than that of lower canine. Copyright © 2018 Elsevier B.V. All rights reserved.

Epigenetic predictor of age.

Directory of Open Access Journals (Sweden)

Sven Bocklandt

Full Text Available From the moment of conception, we begin to age. A decay of cellular structures, gene regulation, and DNA sequence ages cells and organisms. DNA methylation patterns change with increasing age and contribute to age related disease. Here we identify 88 sites in or near 80 genes for which the degree of cytosine methylation is significantly correlated with age in saliva of 34 male identical twin pairs between 21 and 55 years of age. Furthermore, we validated sites in the promoters of three genes and replicated our results in a general population sample of 31 males and 29 females between 18 and 70 years of age. The methylation of three sites--in the promoters of the EDARADD, TOM1L1, and NPTX2 genes--is linear with age over a range of five decades. Using just two cytosines from these loci, we built a regression model that explained 73% of the variance in age, and is able to predict the age of an individual with an average accuracy of 5.2 years. In forensic science, such a model could estimate the age of a person, based on a biological sample alone. Furthermore, a measurement of relevant sites in the genome could be a tool in routine medical screening to predict the risk of age-related diseases and to tailor interventions based on the epigenetic bio-age instead of the chronological age.

Testing principle working mechanisms of the health action process approach for subjective physical age groups.

Science.gov (United States)

Wienert, Julian; Kuhlmann, Tim; Fink, Sebastian; Hambrecht, Rainer; Lippke, Sonia

2016-01-01

This study investigated differences in social-cognitive predictors and self-regulatory planning, as proposed by the health action process approach (HAPA), across three different subjective physical age groups for physical activity. With a cross-sectional design, 521 participants across the chronological age span from 25 to 86 years (M = 48.79; SD = 12.66) were separated into three groups: those who feel physically younger than they are in terms of chronological age, the same perceived and chronological age, and feeling physically older compared to their chronological age. Participants were assessed regarding their perceived vulnerability, outcome expectancies, general intentions, planning, self-efficacy, and stages of physical activity (non-intenders, intenders, and actors). Data were analysed via mean comparison and multigroup structural equation modelling. Mean differences for all but one construct were eminent in all groups, generally showing that those feeling physically younger also report better social-cognitive predictors of physical activity (e.g. lower perceived vulnerability) in comparison to those who feel the same age or older. The model showed that basic working mechanisms of the HAPA can be applied to all groups. With that, the results provide for the first time evidence that principle working mechanism of the HAPA can be applied to all subjective physical age groups. These may be used to tailor health promoting interventions according to participants' needs as a more suitable proxy than chronological age.

Third molar maturity index (I3M) for assessing age of majority: study of a black South African sample.

Science.gov (United States)

Angelakopoulos, N; De Luca, S; Velandia Palacio, L A; Coccia, E; Ferrante, L; Cameriere, R

2018-03-08

The evaluation of the cutoff value of I 3M  = 0.08 for discriminating black South African minors from adults, and its relationship with chronological age. A sample of 833 panoramic radiographs of healthy black South African subjects (500 females and 333 males), in the age range of 14 to 24 years (mean age 17.67 years in females and 17.42 years in males), was retrospectively evaluated. ICC values were 99.10% (95% CI 97.70 to 99.70%) and 99.20% (95% CI 98.00 to 99.60%), for the intra- and inter-observer reliability, respectively. I 3M decreased as the real age gradually increased in both sexes. According to the logistic regression model, the variable sex was not significant when the probability that an individual is 18 years or older was calculated. The I 3M  = 0.08 was valuable in discriminating between adults and minors. The overall accuracy (ACC = fraction of accurately classified subjects) is 0.90 (95% CI 0.87-0.91); the proportion of correctly classified subjects (Se = sensitivity) is 0.80 (95% CI 0.76-0.84), and specificity (Sp) is 0.95 (95% CI 0.93-0.97). The PPV (predictive positive value) is 0.96 (95% CI 0.95-0.97), and the negative predictive value is 0.76 (95% CI 0.72-0.80). The results show that I 3M is a valuable method to distinguish subjects who are around legal adult age in South Africa.

Dental maturity of Saudi children: Role of ethnicity in age determination

International Nuclear Information System (INIS)

Baghdadi, Ziad D.

2013-01-01

Demirjian's dental maturity scores and curves have been widely used for human age determination. Several authors have reported considerable differences between the true and estimated age based on the Demirjian curves, which have been accounted for by ethnicity. The purpose of the current study was to assess the role of ethnicity-specific dental maturation curves in age estimation of Saudi children. A sample of 452 healthy Saudi children aged 4 to 14 years were aged based on the original French-Canadian Demirjian curves and several modified Demirjian curves specified for certain ethnic groups: Saudi, Kuwaiti, Polish, Dutch, Pakistani, and Belgian. One-way ANOVA and a post hoc Scheffe's test were used to assess the differences between chronological age and dental age estimated by the different curves (P<0.05). The curves designed for Dutch, Polish, Saudi, and Belgian (5th percentile) populations had a significantly lower error in estimating age than the original French-Canadian and Belgian (50th percentile) curves. The optimal curve for males was the Saudi one, with a mean absolute difference between estimated age and chronological age of 8.6 months. For females, the optimal curve was the Polish one, with a mean absolute difference of 7.4 months. It was revealed that accurate age determination was not related to certain ethnicity-specific curves. We conclude that ethnicity might play a role in age determination, but not a principal one.

Dental maturity of Saudi children: Role of ethnicity in age determination

Energy Technology Data Exchange (ETDEWEB)

Baghdadi, Ziad D. [Dept. of Preventive Dentistry, Riyadh Colleges of Dentistry and Pharmacy, Riyadh (Saudi Arabia)

2013-12-15

Demirjian's dental maturity scores and curves have been widely used for human age determination. Several authors have reported considerable differences between the true and estimated age based on the Demirjian curves, which have been accounted for by ethnicity. The purpose of the current study was to assess the role of ethnicity-specific dental maturation curves in age estimation of Saudi children. A sample of 452 healthy Saudi children aged 4 to 14 years were aged based on the original French-Canadian Demirjian curves and several modified Demirjian curves specified for certain ethnic groups: Saudi, Kuwaiti, Polish, Dutch, Pakistani, and Belgian. One-way ANOVA and a post hoc Scheffe's test were used to assess the differences between chronological age and dental age estimated by the different curves (P<0.05). The curves designed for Dutch, Polish, Saudi, and Belgian (5th percentile) populations had a significantly lower error in estimating age than the original French-Canadian and Belgian (50th percentile) curves. The optimal curve for males was the Saudi one, with a mean absolute difference between estimated age and chronological age of 8.6 months. For females, the optimal curve was the Polish one, with a mean absolute difference of 7.4 months. It was revealed that accurate age determination was not related to certain ethnicity-specific curves. We conclude that ethnicity might play a role in age determination, but not a principal one.

Dental age estimation: the role of probability estimates at the 10 year threshold.

Science.gov (United States)

Lucas, Victoria S; McDonald, Fraser; Neil, Monica; Roberts, Graham

2014-08-01

The use of probability at the 18 year threshold has simplified the reporting of dental age estimates for emerging adults. The availability of simple to use widely available software has enabled the development of the probability threshold for individual teeth in growing children. Tooth development stage data from a previous study at the 10 year threshold were reused to estimate the probability of developing teeth being above or below the 10 year thresh-hold using the NORMDIST Function in Microsoft Excel. The probabilities within an individual subject are averaged to give a single probability that a subject is above or below 10 years old. To test the validity of this approach dental panoramic radiographs of 50 female and 50 male children within 2 years of the chronological age were assessed with the chronological age masked. Once the whole validation set of 100 radiographs had been assessed the masking was removed and the chronological age and dental age compared. The dental age was compared with chronological age to determine whether the dental age correctly or incorrectly identified a validation subject as above or below the 10 year threshold. The probability estimates correctly identified children as above or below on 94% of occasions. Only 2% of the validation group with a chronological age of less than 10 years were assigned to the over 10 year group. This study indicates the very high accuracy of assignment at the 10 year threshold. Further work at other legally important age thresholds is needed to explore the value of this approach to the technique of age estimation. Copyright © 2014. Published by Elsevier Ltd.

How age matters : Exploring contemporary Dutch debates on age and sex work

NARCIS (Netherlands)

S.V. Coumans (Sara Vida)

2014-01-01

textabstractSocial protection policies regarding sex work in The Netherlands use ‘age’ as an instrument to create binaries between adults and young people. The concept ‘chronological age’ assumes that age is a static feature and supports the process of categorization; however, age is a socially

Kex1 protease is involved in yeast cell death induced by defective N-glycosylation, acetic acid, and chronological aging.

Science.gov (United States)

Hauptmann, Peter; Lehle, Ludwig

2008-07-04

N-glycosylation in the endoplasmic reticulum is an essential protein modification and highly conserved in evolution from yeast to humans. The key step of this pathway is the transfer of the lipid-linked core oligosaccharide to the nascent polypeptide chain, catalyzed by the oligosaccharyltransferase complex. Temperature-sensitive oligosaccharyltransferase mutants of Saccharomyces cerevisiae at the restrictive temperature, such as wbp1-1, as well as wild-type cells in the presence of the N-glycosylation inhibitor tunicamycin display typical apoptotic phenotypes like nuclear condensation, DNA fragmentation, phosphatidylserine translocation, caspase-like activity, and reactive oxygen species accumulation. Since deletion of the yeast metacaspase YCA1 did not abrogate this death pathway, we postulated a different proteolytic process to be responsible. Here, we show that Kex1 protease is involved in the programmed cell death caused by defective N-glycosylation. Its disruption decreases caspase-like activity, production of reactive oxygen species, and fragmentation of mitochondria and, conversely, improves growth and survival of cells. Moreover, we demonstrate that Kex1 contributes also to the active cell death program induced by acetic acid stress or during chronological aging, suggesting that Kex1 plays a more general role in cellular suicide of yeast.

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)

Meresse, F.

2013-02-01

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 U 238 nucleus entails the formation of one fission track. The determination of the initial quantity of U 238 is based on the natural steady ratio U 238 /U 235 which equals 137.88. The initial quantity of U 235 is determined through the neutron irradiation of the sample. The knowledge of the initial quantity of U 238 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

Fibroblast-mediated contraction in actinically exposed and actinically protected aging skin

International Nuclear Information System (INIS)

Marks, M.W.; Morykwas, M.J.; Wheatley, M.J.

1990-01-01

The changes in skin morphology over time are a consequence of both chronologic aging and the accumulation of environmental exposure. Through observation, we know that actinic radiation intensifies the apparent aging of skin. We have investigated the effects of aging and actinic radiation on the ability of fibroblasts to contract collagen-fibroblast lattices. Preauricular and postauricular skin samples were obtained from eight patients aged 49 to 74 undergoing rhytidectomy. The samples were kept separate, and the fibroblasts were grown in culture. Lattices constructed with preauricular fibroblasts consistently contracted more than lattices containing postauricular fibroblasts. The difference in amount of contraction in 7 days between sites was greatest for the younger patients and decreased linearly as donor age increased (r = -0.96). This difference may be due to preauricular fibroblasts losing their ability to contract a lattice as aging skin is exposed to more actinic radiation

Subjective Age in Early Adolescence: Relationships with Chronological Age, Pubertal Timing, Desired Age, and Problem Behaviors

Science.gov (United States)

Hubley, Anita M.; Arim, Rubab G.

2012-01-01

Subjective age generally refers to the age that one feels. In a cross-sectional questionnaire study of 245 adolescents ages 10-14 years, we examined (a) whether, and when, a cross-over in subjective age occurs, (b) differences in subjective age among pubertal timing groups, (c) correlations between subjective age and each of desired age and five…

A Chronological History of Puerto Rico.

Science.gov (United States)

Tovar, Federico Ribes

This book presents a chronological history of Puerto Rico from prehistory and discovery through December of 1972. It includes information on the persons and events that influenced the course of Puerto Rican history. A table of contents and a selective index are included. (Author/AM)

Western Saudi adolescent age estimation utilising third molar development.

Science.gov (United States)

Alshihri, Amin M; Kruger, Estie; Tennant, Marc

2014-07-01

The aim of this study was to establish reference data on third molar morphology/development for age estimation in Western Saudi adolescents, between ages 14 and 23 years of old. The orthopantomograms of 130 individuals (males and females), were examined, and the stage of third molar development were evaluated. Mean ages, standard deviations, and percentile distributions are presented for each stage of development. The mean estimated age for all participants (n = 130) was 219.7 months, and this differed significantly (P age (226.5 months). Deviations of predicted age from real age showed 28.5% of all participants had their age estimated within 1 year (±12 months) of their chronological age. Most (43%) had their age underestimated by more than 12 months and the remaining 28.5% had their age overestimated by more than 12 months of their chronological age. Differences in left-right symmetry information of third molars were detected and were higher in the maxilla (92%) than in the mandible (82%). For all molars reaching stage "H" most individuals (males and females) were over the age 18 years of old. Males reach the developmental stages earlier than females. Third molar tooth development can be reliably used to generate mean age and the estimated age range for an individual of unknown chronological age. Further studies with large populations are needed for better statistical results.

The luminescence dating chronology of a deep core from Bosten Lake (NW China) in arid central Asia reveals lake evolution over the last 220 ka

DEFF Research Database (Denmark)

Li, Guoqiang; Duan, Yanwu; Huang, Xiaozhong

2016-01-01

The lacustrine deposits of lakes in arid central Asia (ACA) potentially record palaeoclimatic changes on orbital and suborbital time scales, but such changes are still poorly understood due to the lack of reliable chronologies. Bosten Lake, the largest freshwater inland lake in China, is located...... in the southern Tianshan Mountains in central ACA. A 51.6-m-deep lacustrine succession was retrieved from the lake and 30 samples from the succession were used for luminescence dating to establish a chronology based on multi-grain quartz OSL and K-feldspar post-IR IRSL (pIRIR290) dating. Quartz OSL ages were only....... A stable deep lake occurred at c. 220, 210–180, c. 165, 70–60, 40–30 and 20–5 ka, while shallow levels occurred at c. 215, 180–165, 100–70, 60–40 and 30–20 ka. Bosten Lake levels decreased by at least ~29 m and possibly the lake even dried up between c. 160 and c. 100 ka. We suggest that the water...

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

Directory of Open Access Journals (Sweden)

Yablonsky Leonid Teodorovich

2015-12-01

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

Feeling sad makes us feel older: Effects of a sad-mood induction on subjective age.

Science.gov (United States)

Dutt, Anne J; Wahl, Hans-Werner

2017-08-01

A mood-induction paradigm was implemented in a sample of 144 adults covering midlife and old age (40-80 years) to investigate associations between mood and subjective age. Sad or neutral mood was induced by texts and music pieces. Subjective age was operationalized as felt age relative to chronological age. Participants receiving the sad-mood induction reported changes toward older felt ages from pre- to postinduction. Participants receiving the neutral-mood induction reported comparable levels of subjective age at pre- and postinduction. Effects were comparable across middle- and older aged participants. Results suggest that sad affective states might dampen subjective age. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Increased brain-predicted aging in treated HIV disease.

Science.gov (United States)

Cole, James H; Underwood, Jonathan; Caan, Matthan W A; De Francesco, Davide; van Zoest, Rosan A; Leech, Robert; Wit, Ferdinand W N M; Portegies, Peter; Geurtsen, Gert J; Schmand, Ben A; Schim van der Loeff, Maarten F; Franceschi, Claudio; Sabin, Caroline A; Majoie, Charles B L M; Winston, Alan; Reiss, Peter; Sharp, David J

2017-04-04

To establish whether HIV disease is associated with abnormal levels of age-related brain atrophy, by estimating apparent brain age using neuroimaging and exploring whether these estimates related to HIV status, age, cognitive performance, and HIV-related clinical parameters. A large sample of virologically suppressed HIV-positive adults (n = 162, age 45-82 years) and highly comparable HIV-negative controls (n = 105) were recruited as part of the Comorbidity in Relation to AIDS (COBRA) collaboration. Using T1-weighted MRI scans, a machine-learning model of healthy brain aging was defined in an independent cohort (n = 2,001, aged 18-90 years). Neuroimaging data from HIV-positive and HIV-negative individuals were then used to estimate brain-predicted age; then brain-predicted age difference (brain-PAD = brain-predicted brain age - chronological age) scores were calculated. Neuropsychological and clinical assessments were also carried out. HIV-positive individuals had greater brain-PAD score (mean ± SD 2.15 ± 7.79 years) compared to HIV-negative individuals (-0.87 ± 8.40 years; b = 3.48, p brain-PAD score was associated with decreased performance in multiple cognitive domains (information processing speed, executive function, memory) and general cognitive performance across all participants. Brain-PAD score was not associated with age, duration of HIV infection, or other HIV-related measures. Increased apparent brain aging, predicted using neuroimaging, was observed in HIV-positive adults, despite effective viral suppression. Furthermore, the magnitude of increased apparent brain aging related to cognitive deficits. However, predicted brain age difference did not correlate with chronological age or duration of HIV infection, suggesting that HIV disease may accentuate rather than accelerate brain aging. Copyright © 2017 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.

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.;

Yeast chronological lifespan and proteotoxic stress: is autophagy good or bad?

Science.gov (United States)

Sampaio-Marques, Belém; Felgueiras, Carolina; Silva, Alexandra; Rodrigues, Fernando; Ludovico, Paula

2011-10-01

Autophagy, a highly conserved proteolytic mechanism of quality control, is essential for the maintenance of metabolic and cellular homoeostasis and for an efficient cellular response to stress. Autophagy declines with aging and is believed to contribute to different aspects of the aging phenotype. The nutrient-sensing pathways PKA (protein kinase A), Sch9 and TOR (target of rapamycin), involved in the regulation of yeast lifespan, also converge on a common targeted process: autophagy. The molecular mechanisms underlying the regulation of autophagy and aging by these signalling pathways in yeast, with special attention to the TOR pathway, are discussed in the present paper. The question of whether or not autophagy could contribute to yeast cell death occurring during CLS (chronological lifespan) is discussed in the light of our findings obtained after autophagy activation promoted by proteotoxic stress. Autophagy progressively increases in cells expressing the aggregation-prone protein α-synuclein and seems to participate in the early cell death and shortening of CLS under these conditions, highlighting that autophagic activity should be maintained below physiological levels to exert its promising anti-aging effects.

Accelerated Brain Aging in Schizophrenia: A Longitudinal Pattern Recognition Study.

Science.gov (United States)

Schnack, Hugo G; van Haren, Neeltje E M; Nieuwenhuis, Mireille; Hulshoff Pol, Hilleke E; Cahn, Wiepke; Kahn, René S

2016-06-01

Despite the multitude of longitudinal neuroimaging studies that have been published, a basic question on the progressive brain loss in schizophrenia remains unaddressed: Does it reflect accelerated aging of the brain, or is it caused by a fundamentally different process? The authors used support vector regression, a supervised machine learning technique, to address this question. In a longitudinal sample of 341 schizophrenia patients and 386 healthy subjects with one or more structural MRI scans (1,197 in total), machine learning algorithms were used to build models to predict the age of the brain and the presence of schizophrenia ("schizophrenia score"), based on the gray matter density maps. Age at baseline ranged from 16 to 67 years, and follow-up scans were acquired between 1 and 13 years after the baseline scan. Differences between brain age and chronological age ("brain age gap") and between schizophrenia score and healthy reference score ("schizophrenia gap") were calculated. Accelerated brain aging was calculated from changes in brain age gap between two consecutive measurements. The age prediction model was validated in an independent sample. In schizophrenia patients, brain age was significantly greater than chronological age at baseline (+3.36 years) and progressively increased during follow-up (+1.24 years in addition to the baseline gap). The acceleration of brain aging was not constant: it decreased from 2.5 years/year just after illness onset to about the normal rate (1 year/year) approximately 5 years after illness onset. The schizophrenia gap also increased during follow-up, but more pronounced variability in brain abnormalities at follow-up rendered this increase nonsignificant. The progressive brain loss in schizophrenia appears to reflect two different processes: one relatively homogeneous, reflecting accelerated aging of the brain and related to various measures of outcome, and a more variable one, possibly reflecting individual variation and

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 in...

Atmospheric Heavy Metal Pollution - Development of Chronological ...

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 4. Atmospheric Heavy Metal Pollution - Development of Chronological Records and Geochemical Monitoring. Rohit Shrivastav. General Article Volume 6 Issue 4 April 2001 pp 62-68 ...

Astronautics and aeronautics, 1976. A chronology

Science.gov (United States)

Ritchie, E. H.

1984-01-01

A chronology of events concerning astronautics and aeronautics for the year 1976 is presented. Some of the many and varied topics include the aerospace industry, planetary exploration, space transportation system, defense department programs, politics, and aerospace medicine. The entries are organized by the month and presented in a news release format.

Attitudes Towards Ads and Age: A Study in Seniors

Directory of Open Access Journals (Sweden)

Marta M. Estrada

2014-08-01

Full Text Available 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, attitude towards the brand and purchasing intention among older adults, noting the moderating effect of the joint use of chronological age and cognitive age on these items. 

Chronological changes in lung cancer surgery in a single Japanese institution

Science.gov (United States)

Nakamura, Haruhiko; Sakai, Hiroki; Kimura, Hiroyuki; Miyazawa, Tomoyuki; Marushima, Hideki; Saji, Hisashi

2017-01-01

Background The aim of this study was to evaluate the chronological changes in epidemiological factors and surgical outcomes in patients with lung cancer who underwent surgery in a single Japanese institution. Patients and methods A clinicopathological database of patients with lung cancer who underwent surgery with curative intent from January 1974 to December 2014 was reviewed. The chronological changes in various factors, including patient’s age, sex, histological type, tumor size, pathological stage (p-stage), surgical method, operative time, intraoperative blood loss, 30-day mortality, and postoperative overall survival (OS), were evaluated. Results A total of 1,616 patients were included. The numbers of resected patients, females, adenocarcinomas, p-stage IA patients, and age at the time of surgery increased with time, but tumor size decreased (all P<0.0001). Concerning surgical methods, the number of sublobar resections increased, but that of pneumonectomies decreased (P<0.0001). The mean operative time, intraoperative blood loss, and the postoperative 30-day mortality rate decreased (all P<0.0001). When the patients were divided into two groups (1974–2004 and 2005–2014), the 5-year OS rates for all patients and for p-stage IA patients improved from 44% to 79% and from 73% to 89%, respectively (all P<0.0001). The best 5-year OS rate was obtained for sublobar resection (73%), followed by lobectomy (60%), combined resection (22%), and pneumonectomy (21%; P<0.0001). Conclusion Changes in epidemiological factors, a trend toward less invasive surgery, and a remarkably improved postoperative OS were confirmed, which demonstrated the increasingly important role of surgery in therapeutic strategies for lung cancer. PMID:28331339

Reservoir effects in a Stone Age fjord on Lolland, Denmark

DEFF Research Database (Denmark)

Philippsen, Bente

2018-01-01

to be known for accurate radiocarbon dating of samples with possible aquatic carbon sources, such as human bones or food residues on pottery. Therefore, this paper attempts at calculating the local reservoir effect for the study area. I will discuss the possibilities and limitations when analysing radiocarbon...... for building chronologies and for reconstructing the environment of the Stone Age fjord. Finally, I will discuss the pitfalls and uncertainties associated with radiocarbon dates for sea level reconstruction....

Evaluation rate of aging person based on determination of biological age

Directory of Open Access Journals (Sweden)

V. Fil

2015-01-01

2Kazimierz Wielki University, Bydgoszcz, Poland   Abstract The article considers the value of biological and passport age of student youth. In experiment participated 140 students aged 17-19 years. Calculated their biological age. Reviewed pace of aging of the body of students. Detected indexes that have the strongest relationship with indicators of biological age. The results compared with researchers of other regions of Ukraine.   Keywords: chronological (passport age, biological age, appropriate biological age, pulse blood pressure, rate of aging, static balancing, self-reported level of health.

Transcriptional and Cell Cycle Alterations Mark Aging of Primary Human Adipose-Derived Stem Cells.

Science.gov (United States)

Shan, Xiaoyin; Roberts, Cleresa; Kim, Eun Ji; Brenner, Ariana; Grant, Gregory; Percec, Ivona

2017-05-01

Adult stem cells play a critical role in the maintenance of tissue homeostasis and prevention of aging. While the regenerative potential of stem cells with low cellular turnover, such as adipose-derived stem cells (ASCs), is increasingly recognized, the study of chronological aging in ASCs is technically difficult and remains poorly understood. Here, we use our model of chronological aging in primary human ASCs to examine genome-wide transcriptional networks. We demonstrate first that the transcriptome of aging ASCs is distinctly more stable than that of age-matched fibroblasts, and further, that age-dependent modifications in cell cycle progression and translation initiation specifically characterize aging ASCs in conjunction with increased nascent protein synthesis and a distinctly shortened G1 phase. Our results reveal novel chronological aging mechanisms in ASCs that are inherently different from differentiated cells and that may reflect an organismal attempt to meet the increased demands of tissue and organ homeostasis during aging. Stem Cells 2017;35:1392-1401. © 2017 AlphaMed Press.

Astronautics and Aeronautics, 1979-1984: A chronology

Science.gov (United States)

Janson, Bette R.; Ritchie, Eleanor H.

1989-01-01

This volume of the Astronautics and Aeronautics series covers 1979 through 1984. The series provides a chronological presentation of all significant events and developments in space exploration and the administration of the space program during the period covered.

Preliminary study of the chronology of the sedimentation process in lakes

International Nuclear Information System (INIS)

Patrocinio Junior, Antonio C.; Andrello, Avacir C.

2009-01-01

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)

New ages for Middle and Later Stone Age deposits at Mumba rockshelter, Tanzania: optically stimulated luminescence dating of quartz and feldspar grains.

Science.gov (United States)

Gliganic, Luke A; Jacobs, Zenobia; Roberts, Richard G; Domínguez-Rodrigo, Manuel; Mabulla, Audax Z P

2012-04-01

The archaeological deposits at Mumba rockshelter, northern Tanzania, have been excavated for more than 70 years, starting with Margit and Ludwig Köhl-Larsen in the 1930s. The assemblages of Middle Stone Age (MSA) and Later Stone Age (LSA) artefacts collected from this site constitute the type sequences for these cultural phases in East Africa. Despite its archaeological importance, however, the chronology of the site is poorly constrained, despite the application since the 1980s of several dating methods (radiocarbon, uranium-series and amino acid racemisation) to a variety of materials recovered from the deposits. Here, we review these previous chronologies for Mumba and report new ages obtained from optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL) measurements on single grains of quartz and multi-grain aliquots of potassium (K) feldspar from the MSA and LSA deposits. Measurements of single grains of quartz allowed the rejection of unrepresentative grains and the application of appropriate statistical models to obtain the most reliable age estimates, while measurements of K-feldspars allowed the chronology to be extended to older deposits. The seven quartz ages and four K-feldspar ages provide improved temporal constraints on the archaeological sequence at Mumba. The deposits associated with the latest Kisele Industry (Bed VI-A) and the earliest Mumba Industry (Bed V) are dated to 63.4 ± 5.7 and 56.9 ± 4.8 ka (thousands of years ago), respectively, thus constraining the time of transition between these two archaeological phases to ~60 ka. An age of 49.1 ± 4.3 ka has been obtained for the latest deposits associated with the Mumba Industry, which show no evidence for post-depositional mixing and contain ostrich eggshell (OES) beads and abundant microlithics. The Nasera Industry deposits (Bed III) contain large quantities of OES beads and date to 36.8 ± 3.4 ka. We compare the luminescence ages with the previous chronologies for

Assessment of bone age in prepubertal healthy Korean children: Comparison among the Korean standard bone age chart, Greulich-Pyle method, and Tanner-Whitehouse method

International Nuclear Information System (INIS)

Kim Jeong Rye; Lee, Young Seok; Yu, Jee Suk

2015-01-01

To compare the reliability of the Greulich-Pyle (GP) method, Tanner-Whitehouse 3 (TW3) method and Korean standard bone age chart (KS) in the evaluation of bone age of prepubertal healthy Korean children. Left hand-wrist radiographs of 212 prepubertal healthy Korean children aged 7 to 12 years, obtained for the evaluation of the traumatic injury in emergency department, were analyzed by two observers. Bone age was estimated using the GP method, TW3 method and KS, and was calculated in months. The correlation between bone age measured by each method and chronological age of each child was analyzed using Pearson correlation coefficient, scatterplot. The three methods were compared using one-way analysis of variance. Significant correlations were found between chronological age and bone age estimated by all three methods in whole group and in each gender (R2 ranged from 0.87 to 0.9, p < 0.01). Although bone age estimated by KS was slightly closer to chronological age than those estimated by the GP and TW3 methods, the difference between three methods was not statistically significant (p > 0.01). The KS, GP, and TW3 methods show good reliability in the evaluation of bone age of prepubertal healthy Korean children without significant difference between them. Any are useful for evaluation of bone age in prepubertal healthy Korean children.

isotopic chronological study on gold-stibium deposits in Bayinbuluke area of Tianshan mountains

International Nuclear Information System (INIS)

Chen Fuwen; Li Huaqin

2003-01-01

Several gold-stibium deposits have recently been found in Bayinbuluke area of Tianshan Mountains, such as the Dashankou gold deposit and Chahansala stibium deposit. isotopic chronological study of mineralization show that the fluid inclusion Rb-Sr isochron age for gold-bearing pyrite-quartz veins and pyrite-limonite-quartz veins from the Dashankou gold mine are 354 ± 8.1 Ma (2 σ) and 344 ± 21 Ma (2 σ), respectively. The two ages are consistent in test errors, indicating the gold deposit was formed in early Carboniferous and related to regional shearing; the fluid inclusion Rb-Sr isochron age for quartz-stibnite veins and quartz-tetrahedrite-bismuthinite-stibnite veins from the Chahansala stibium mine is 257 ± 23 Ma (2 σ), indicating the deposit was formed during the late Hercynian-Early Indosinian Period and related to intracontinental deformation. (authors)

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)

The Antarctic ice core chronology (AICC2012): an optimized multi-parameter and multi-site dating approach for the last 120 thousand years

Science.gov (United States)

Veres, D.; Bazin, L.; Landais, A.; Toyé Mahamadou Kele, H.; Lemieux-Dudon, B.; Parrenin, F.; Martinerie, P.; Blayo, E.; Blunier, T.; Capron, E.; Chappellaz, J.; Rasmussen, S. O.; Severi, M.; Svensson, A.; Vinther, B.; Wolff, E. W.

2013-08-01

expected that the future contribution of both other long ice core records and other types of chronological constraints to the Datice tool will lead to further refinements in the ice core chronologies beyond the AICC2012 chronology. For the time being however, we recommend that AICC2012 be used as the preferred chronology for the Vostok, EDC, EDML and TALDICE ice core records, both over the last glacial cycle (this study), and beyond (following Bazin et al., 2013). The ages for NGRIP in AICC2012 are virtually identical to those of GICC05 for the last 60.2 ka, whereas the ages beyond are independent of those in GICC05modelext (as in the construction of AICC2012, the GICC05modelext was included only via the background scenarios and not as age markers). As such, where issues of phasing between Antarctic records included in AICC2012 and NGRIP are involved, the NGRIP ages in AICC2012 should therefore be taken to avoid introducing false offsets. However for issues involving only Greenland ice cores, there is not yet a strong basis to recommend superseding GICC05modelext as the recommended age scale for Greenland ice cores.

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

2013-08-01

. It is expected that the future contribution of both other long ice core records and other types of chronological constraints to the Datice tool will lead to further refinements in the ice core chronologies beyond the AICC2012 chronology. For the time being however, we recommend that AICC2012 be used as the preferred chronology for the Vostok, EDC, EDML and TALDICE ice core records, both over the last glacial cycle (this study, and beyond (following Bazin et al., 2013. The ages for NGRIP in AICC2012 are virtually identical to those of GICC05 for the last 60.2 ka, whereas the ages beyond are independent of those in GICC05modelext (as in the construction of AICC2012, the GICC05modelext was included only via the background scenarios and not as age markers. As such, where issues of phasing between Antarctic records included in AICC2012 and NGRIP are involved, the NGRIP ages in AICC2012 should therefore be taken to avoid introducing false offsets. However for issues involving only Greenland ice cores, there is not yet a strong basis to recommend superseding GICC05modelext as the recommended age scale for Greenland ice cores.

Astronautics and aeronautics, 1978: A chronology

Science.gov (United States)

Janson, Bette R.

1986-01-01

This is the 18th in a series of annual chronologies of significant events in the fields of astronautics and aeronautics. Events covered are international as well as national and political as well as scientific and technical. This series is a reference work for historians, NASA personnel, government agencies, congressional staffs, and the media.

Recent growth coherence in long-term oak (Quercus spp.) ring width chronologies in the Czech Republic

Czech Academy of Sciences Publication Activity Database

Dobrovolný, Petr; Rybníček, Michal; Büntgen, Ulf; Trnka, Miroslav; Brázdil, Rudolf; Stachoň, Z.; Prokop, O.; Kolář, Tomáš

2016-01-01

Roč. 70, 2-3 (2016), s. 133-141 ISSN 0936-577X R&D Projects: GA MŠk(CZ) LO1415; GA ČR GA13-04291S; GA MŠk(CZ) EE2.3.20.0248 Institutional support: RVO:67179843 Keywords : Tree-ring width chronology * Oak species * Tree-age structure * Site-specific conditions * Hydroclimate sensitivity * Czech Republic Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 1.578, year: 2016

History of Science in the United States: A Chronology and Research Guide, by Clark A. Elliott, Garland Reference Library of the Humanities Vol. 1711, Garland Publishing, New York. 1996

OpenAIRE

Christenson, Andrew L.

1996-01-01

There are four parts to this volume - a chronology of events by year, a chronology of leading scientists grouped by the decade in which they reached 25 years of age? a research guide, and a research bibliography. The author has written extensively on American science, including co-editing the volume Science at Harvard University (reviewed in BHA 2(1):17-19). The volume covers mostly what are termed the "hard" sciences ...

A developing chronology for prehistoric 'moated sites' in northeast Thailand

International Nuclear Information System (INIS)

McGrath, R.J.; Boyd, W.E.

1999-01-01

Full text: Many mounded Iron Age occupation sites in the Mun River Valley,N.E. Thailand are characterised by distinctive encircling earthworks, these are commonly known as 'moated sites'. The first excavations of any significance within the moats themselves at six sites -Noen U-Loke, Non Muang Khao, Ban Non Khrua Chut, Ban Non Ngiu, Ban Makham Thae and Ban Non Wat - in the form of long trenches have been carried out to enable detailed examination of their structure. Significantly, the surficial morphology of the moats, and the notable regularity of shape and patterning of the moats in plan, usually does not accurately reflect the buried sectional morphology of incised channel features, which are in no way expressed on the surface. Buried channels beneath the edge of the mounds as well as the surrounding moat banks have also been revealed. Stratigraphic and geomorphic relationships of the buried features imply critical chronological relationships which need to be tested to allow full development of a model for the evolution of the archaeological sites. Extremely small quantities of charcoal and shells obtained from the buried features has necessitated the need for AMS dating to develop the chronology for the development, use and decline of the moated features and channels. The dating is an ongoing process, however, results thus far obtained supports the development of older channels towards the archaeological mounds, and yet older buried channels under the sites

Astronautics and aeronautics, 1985: A chronology

Science.gov (United States)

Janson, Bette R.

1988-01-01

This book is part of a series of annual chronologies of significant events in the fields of astronautics and aeronautics. Events covered are international as well as national, in political as well as scientific and technical areas. This series is an important reference work used by historians, NASA personnel, government agencies, and congressional staffs, as well as the media.

Age estimation of living Indian individuals based on aspartic acid racemization from tooth biopsy specimen

Science.gov (United States)

Rastogi, Manu; Logani, Ajay; Shah, Naseem; Kumar, Abhishek; Arora, Saurabh

2017-01-01

Background: Age estimation in living individuals is imperative to amicably settle civil and criminal disputes. A biochemical method based on amino acid racemization was evaluated for age estimation of living Indian individuals. Design: Caries-free maxillary/mandibular premolar teeth (n = 90) were collected from participants with age proof documents and divided into predefined nine age groups. Materials and Methods: Dentine biopsy from the labial aspect of the tooth crown was taken with an indigenously developed microtrephine. The samples were processed and subjected to gas chromatography. Dextrorotatory:levorotatory ratios were calculated, and a regression equation was formulated. Results: Across all age groups, an error of 0 ± 4 years between protein racemization age and chronological age was observed. Conclusion: Aspartic acid racemization from dentine biopsy samples could be a viable and accurate technique for age estimation of living individuals who have attained a state of skeletal maturity. PMID:29263613

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.

Non-genetic impact factors on chronological lifespan and stress resistance of baker’s yeast

Directory of Open Access Journals (Sweden)

Michael Sauer

2016-04-01

Full Text Available Survival under nutrient limitation is an essential feature of microbial cells, and it is defined by the chronological lifespan. We summarize recent findings, illustrating how crucial the choice of the experimental setup is for the interpretation of data in this field. Especially the impact of oxygen supply differs depending on the culture type, highlighting the differences of alternatives like the retentostat to classical batch cultures. Finally the importance of culture conditions on cell aging and survival in biotechnological processes is highlighted.

AFSC/REFM: Bomb-produced age validation study

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Fish age validation with bomb-produced radiocarbon (14C) requires a known-age Delta14C reference chronology spanning the era of a marine increase in bomb-produced...

Chronological changes in lung cancer surgery in a single Japanese institution

Directory of Open Access Journals (Sweden)

Nakamura H

2017-03-01

Full Text Available Haruhiko Nakamura, Hiroki Sakai, Hiroyuki Kimura, Tomoyuki Miyazawa, Hideki Marushima, Hisashi Saji Department of Chest Surgery, St Marianna University School of Medicine, Kawasaki, Kanagawa, Japan Background: The aim of this study was to evaluate the chronological changes in epidemiological factors and surgical outcomes in patients with lung cancer who underwent surgery in a single Japanese institution.Patients and methods: A clinicopathological database of patients with lung cancer who underwent surgery with curative intent from January 1974 to December 2014 was reviewed. The chronological changes in various factors, including patient’s age, sex, histological type, tumor size, pathological stage (p-stage, surgical method, operative time, intraoperative blood loss, 30-day mortality, and postoperative overall survival (OS, were evaluated.Results: A total of 1,616 patients were included. The numbers of resected patients, females, adenocarcinomas, p-stage IA patients, and age at the time of surgery increased with time, but tumor size decreased (all P<0.0001. Concerning surgical methods, the number of sublobar resections increased, but that of pneumonectomies decreased (P<0.0001. The mean operative time, intraoperative blood loss, and the postoperative 30-day mortality rate decreased (all P<0.0001. When the patients were divided into two groups (1974–2004 and 2005–2014, the 5-year OS rates for all patients and for p-stage IA patients improved from 44% to 79% and from 73% to 89%, respectively (all P<0.0001. The best 5-year OS rate was obtained for sublobar resection (73%, followed by lobectomy (60%, combined resection (22%, and pneumonectomy (21%; P<0.0001.Conclusion: Changes in epidemiological factors, a trend toward less invasive surgery, and a remarkably improved postoperative OS were confirmed, which demonstrated the increasingly important role of surgery in therapeutic strategies for lung cancer. Keywords: lung cancer, surgery, sublobar

Settlement duration and materiality: formal chronological models for the development of Barnhouse, a Grooved Ware settlement in Orkney

OpenAIRE

Richards, Colin; Jones, Andrew Meirion; MacSween, Ann; Sheridan, Alison; Dunbar, Elaine; Reimer, Paula; Bayliss, Alex; Griffiths, Seren; Whittle, Alasdair

2016-01-01

Radiocarbon dating and Bayesian chronological modelling, undertaken as part of the investigation by the Times of Their Lives project into the development of Late Neolithic settlement and pottery in Orkney, has provided precise new dating for the Grooved Ware settlement of Barnhouse, excavated in 1985–91. Previous understandings of the site and its pottery are presented. A Bayesian model based on 70 measurements on 62 samples (of which 50 samples are thought to date accurately the deposits fro...

Application of skeletal age based on x-ray in selecting sports talents

Science.gov (United States)

Mao, Zongzhen; Xu, Guodong; Song, Tao

2012-01-01

Skeletal age has been studied and proved that for most elite athletes, it was coincident with the chronological ages when they were young. In order to explore the application of skeletal age in selecting sports talent, 32 athletes (female, chronological age 5-12 y) were chosen from the Gymnastics Training Base in this study. Their left hand-wrists were photographed with X-rays, and then the skeletal ages were estimated by Chinese version of the Tanner-Whitehouse Skeletal Maturity Assessment System. At the same time, their body shapes, functions, and sports ability were also measured. Results showed that 71.88% of the skeletal age was proportional to their chronological age (+/- 1 y); while 18.75% of the skeletal maturity was retarded by 1- 2 year, 9.37% of those was advanced more than 1 year. On the other hand, the body shape, functions and sports ability of the athletes were positively related with their skeletal maturity. This study proved that the determination of skeletal maturity is a reliable evaluation for selecting sports talent. A further study on the influence of gymnastics on the skeletal age is of great significance.

Autophagy and leucine promote chronological longevity and respiration proficiency during calorie restriction in yeast.

Science.gov (United States)

Aris, John P; Alvers, Ashley L; Ferraiuolo, Roy A; Fishwick, Laura K; Hanvivatpong, Amanda; Hu, Doreen; Kirlew, Christine; Leonard, Michael T; Losin, Kyle J; Marraffini, Michelle; Seo, Arnold Y; Swanberg, Veronica; Westcott, Jennifer L; Wood, Michael S; Leeuwenburgh, Christiaan; Dunn, William A

2013-10-01

We have previously shown that autophagy is required for chronological longevity in the budding yeast Saccharomyces cerevisiae. Here we examine the requirements for autophagy during extension of chronological life span (CLS) by calorie restriction (CR). We find that autophagy is upregulated by two CR interventions that extend CLS: water wash CR and low glucose CR. Autophagy is required for full extension of CLS during water wash CR under all growth conditions tested. In contrast, autophagy was not uniformly required for full extension of CLS during low glucose CR, depending on the atg allele and strain genetic background. Leucine status influenced CLS during CR. Eliminating the leucine requirement in yeast strains or adding supplemental leucine to growth media extended CLS during CR. In addition, we observed that both water wash and low glucose CR promote mitochondrial respiration proficiency during aging of autophagy-deficient yeast. In general, the extension of CLS by water wash or low glucose CR was inversely related to respiration deficiency in autophagy-deficient cells. Also, autophagy is required for full extension of CLS under non-CR conditions in buffered media, suggesting that extension of CLS during CR is not solely due to reduced medium acidity. Thus, our findings show that autophagy is: (1) induced by CR, (2) required for full extension of CLS by CR in most cases (depending on atg allele, strain, and leucine availability) and, (3) promotes mitochondrial respiration proficiency during aging under CR conditions. Copyright © 2013 Elsevier Inc. All rights reserved.

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.

Standard Chronology in Plato’s Dialogues and Stylometric Evidences

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Mohammad Bagher Ghomi

2015-09-01

Full Text Available Abstract What are to be discussed in this article include two main points: i some kind of a fixed structure can be found in all the chronologies that have been proposed from the last quarter of 19th century onward; a structure that is called here “standard” chronology, and ii in spite of the fact that the appearance of this structure owes too much to the stylistic evidences, these evidences themselves do not confirm anything in the structure but the place of the so-called late dialogues. The standard chronology of Plato’s dialogues is inclined to consider Meno and Republic as dialogues that have been composed after so-called Socratic dialogues and before Parmenides and Theaetetus. This chronology also insists that the latter two dialogues must be dated after so-called middle dialogues and before dialogues like Sophist, Timaeus, Philebus and Laws. This papper is to illuminate the fact that except the similarities between the late dialogues and their probable lateness, the place of other dialogues, more importantly among them the so-called middle period dialogues, Theaetetus and Parmenides, cannot be approved by stylistic evidences.

Distribution of age at menopause in two Danish samples

DEFF Research Database (Denmark)

Boldsen, J L; Jeune, B

1990-01-01

We analyzed the distribution of reported age at natural menopause in two random samples of Danish women (n = 176 and n = 150) to determine the shape of the distribution and to disclose any possible trends in the distribution parameters. It was necessary to correct the frequencies of the reported...... ages for the effect of differing ages at reporting. The corrected distribution of age at menopause differs from the normal distribution in the same way in both samples. Both distributions could be described by a mixture of two normal distributions. It appears that most of the parameters of the normal...... distribution mixtures remain unchanged over a 50-year time lag. The position of the distribution, that is, the mean age at menopause, however, increases slightly but significantly....

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.

Age of majority assessment in Dutch individuals based on Cameriere's third molar maturity index.

Science.gov (United States)

Boyacıoğlu Doğru, Hatice; Gulsahi, Ayşe; Çehreli, Sevi Burçak; Galić, Ivan; van der Stelt, Paul; Cameriere, Roberto

2018-01-01

Radiological examination of the third molar is done in living individuals for estimation of chronological age, especially in the late adolescence. The aim of this study was to assess the application of Cameriere's third molar maturity index (I 3M ) to determine whether an individual is 18 years or older (adult) or younger than 18 years (minor) in a sample of Dutch individuals. The sample consisted of panoramic images of 360 individuals aged between 14 and 22 years old. Three observers performed the measurements. Gender was not statistically significant in discriminating adults and minors. The highest value of the Youden index of the receiver operating curve analysis was for the value of I 3M age assessment in a Dutch population. Copyright © 2017 Elsevier B.V. All rights reserved.

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.

A Chronological Estimation of the Ceremonial Center of Campanayuq Rumi, Ayacucho

OpenAIRE

Matsumoto, Yuichi; Cavero, Yuri

2012-01-01

The main objective of this paper is to construct a site chronology of the Campanayuq Rumi site which is a large ceremonial center of the Formative Period located in the Peruvian south-central highlands. For this purpose, 12 radiocarbon dates obtained from our excavations will be considered in combination with the data of both architectural and ceramic sequences of the site. Through the comprehensive interpretation of these data, we will present a new site chronology of the Campanayuq Rumi sit...

Moraine preservation and boulder erosion in the tropical Andes: interpreting old surface exposure ages in glaciated valleys

Science.gov (United States)

Smith, Jacqueline A.; Finkel, Robert C.; Farber, Daniel L.; Rodbell, Donald T.; Seltzer, Geoffrey O.

2005-10-01

Cosmogenic dating provides a long-awaited means of directly dating glacial deposits that pre-date the last glacial cycle. Although the potential benefits of longer chronologies are obvious, the greater uncertainty associated with older cosmogenic ages may be less readily apparent. We illustrate the challenges of developing and interpreting a long chronology using our data from the Peruvian Andes. We used surface exposure dating with cosmogenic radionuclides (CRNs; 10Be and 26Al) to date 140 boulders on moraines in valleys bordering the Junin Plain (11° S, 76° W) in central Peru. Our chronology spans multiple glacial cycles and includes exposure ages greater than 1 million years, which indicate that long-term rates of boulder erosion have been very low. Interpreting the chronology of moraines for glaciations that predate the last glacial cycle is complicated by the need to consider boulder erosion and exhumation, surface uplift, and inheritance of CRNs from previous exposure intervals. As an example, we recalculate exposure ages using our boulder erosion rates (0.3-0.5 metres per million years) and estimated surface uplift rates to emphasise both the challenges involved in interpreting old surface exposure ages and the value of chronological data, even with large uncertainties, when reconstructing the palaeoclimate of a region.

Cameriere's third molar maturity index in assessing age of majority.

Science.gov (United States)

Galić, Ivan; Lauc, Tomislav; Brkić, Hrvoje; Vodanović, Marin; Galić, Elizabeta; Biazevic, Maria Gabriela Haye; Brakus, Ivan; Badrov, Jozo; Cameriere, Roberto

2015-07-01

Estimation of chronological age of an individual is one of the main challenges in forensic science. Legally to be able to treat a person as a minor or an adult, it is necessary to determine whether their age of majority (if they are older or younger than 18, in most countries). Methods for estimating age are especially important when an individual in question lacks personal documents or other means of identification. As the dental age differs in various populations, the aim of this study was to evaluate applicability of third molar method for assessing age of majority in Croatia. Cameriere's third molar maturity index (I3M) value of 0.08, measured by the open apices of the teeth, was verified in sample of 1336 panoramic images aged between 14 and 23 years. Chronological age gradually decreased as I3M increased in both genders. Males showed statistically significant advanced maturation when I3M was between 0.0 and 0.3 value. The results indicate that the sensitivity of the test for 0.08 value was 84.3% (95%CI 80.6%, 87.5%) for females and 91.2% (95%CI 88.7%, 93.1) for males. Specificity was 95.4% (95%CI 92.5%, 97.5%) and 91.9% (95%CI 88.8%, 94.3%). The proportions of accurately classified males were 88.8% and that of females 91.5%. The estimated post-test probabilities, of individuals, in other word the probability that a Croatian individual with an I3Mthird molar maturity index should be used as a determinant of the age of majority in Croatia. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

A 9111 year long conifer tree-ring chronology for the European Alps : a base for environmental and climatic investigations

NARCIS (Netherlands)

Nicolussi, K.; Kaufmann, M.; Melvin, Thomas M.; van der Plicht, J.; Schiessling, P.; Thurner, A.

An ultra-long tree-ring width chronology (9111 years long, 7109 BC to AD 2002) has been established based on the analysis and dating of 1432 subfossil/dry dead wood samples and cores from 335 living trees. The material was collected from treeline or near-treeline sites (c. 2000 to 2400 m a.s.l.)

Plain Talk About...Aging. Plain Talk Series.

Science.gov (United States)

Kay, Ruth, Ed.

Aging is a state of mind as well as body. The stereotypic image of old age is changing with the increasing variety of living patterns and lifestyles of the elderly. The physical and mental indicators of aging are also varied and do not necessarily keep pace with chronological age. The elderly face changes which challenge their physical and mental…

Examination of DNA methylation status of the ELOVL2 marker may be useful for human age prediction in forensic science.

Science.gov (United States)

Zbieć-Piekarska, Renata; Spólnicka, Magdalena; Kupiec, Tomasz; Makowska, Żanetta; Spas, Anna; Parys-Proszek, Agnieszka; Kucharczyk, Krzysztof; Płoski, Rafał; Branicki, Wojciech

2015-01-01

Age estimation in forensic investigations may complement the prediction of externally visible characteristics and the inference of biogeographical ancestry, thus allowing a better description of an unknown individual. Multiple CpG sites that show linear correlation between age and degree of DNA methylation have been identified in the human genome, providing a selection of candidates for age prediction. In this study, we optimized an assay based on bisulfite conversion and pyrosequencing of 7 CpG sites located in the ELOVL2 gene. Examination of 303 blood samples collected from individuals aged 2-75 years allowed selection of the most informative site, explaining 83% of variation in age. The final linear regression model included two CpG sites in ELOVL2 and enabled age prediction with R(2)=0.859, prediction error=6.85 and mean absolute deviation MAD=5.03. Examination of a testing set of 124 blood samples (MAD=5.75) showed that 68.5% of samples were correctly predicted, assuming that chronological and predicted ages matched ± 7 years. It was found that the ELOVL2 methylation status in bloodstains had not changed significantly after 4 weeks of storage in room temperature conditions. Analysis of 45 bloodstains deposited on tissue paper after 5, 10 and 15 years of storage in room conditions indicated that although a gradual decrease of positive PCR results was observed, the general age prediction success rate remained similar and equaled 60-78%. The obtained results show that the ELOVL2 locus provides a very good source of information about human chronological age based on analysis of blood, including bloodstains, and it may constitute a powerful and reliable predictor in future forensic age estimation models. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Dynamic drawing characteristics of preschool and younger school age children

Directory of Open Access Journals (Sweden)

Cvetković Andrijana

2014-01-01

Full Text Available The main objective of this research is to determine developmental characteristics of dynamic drawings of preschool and younger school age children. The sample consists of 90 typical developed children, aged between 6 and 9. The sample includes 47 (52.2% girls and 43 (47.8% boys from preschool institutions and elementary schools in Pirot and Belgrade. Action representation in dynamic drawings was evaluated using three types of drawings: a man who runs, a man shooting a ball and a man lifting a ball from the floor. We determined that a very small number of the respondents reaches the highest level of graphical representation of figures in motion, and that girl’s achievements are better than boy’s achievements. However, this result is on the border of statistical significance (p=0.052. Also, there is a statistically significant trend of progress to higher levels of action representation (p=0.000 with the increase in chronological age of the respondents.

Constraints on the use of 137Cs as a time-marker to support CRS and SIT chronologies

International Nuclear Information System (INIS)

Abril, J.M.

2004-01-01

CRS and SIT are two 210 Pb-based models widely used in the radiometric dating of recent sediments. 210 Pb chronologies should be validated using at least one independent tracer, such as 137 Cs. This paper demonstrates that simple methods based on the identification of 137 Cs fallout peaks cannot provide a definitive support for CRS and SIT chronologies. Two main arguments will support this assertion: Firstly, the 137 Cs time-marks cannot support a CRS or SIT chronology if the derived sedimentation rates cannot explain the whole 137 Cs activity profile without postulating mixing. Secondly, the support by the 137 Cs time-marks for a given CRS or SIT chronology cannot be considered as definitive if other dating models can equally explain the whole set of data, thereby producing a different chronology. Several case studies selected from the literature are used to support the present discussion. - Simple methods based on the identification of 137 Cs fallout peaks cannot provide a definite support for CRS and SIT chronologies

To Establish the Validity of Dental Age Assessment using Nolla′s Method on Comparing with Skeletal Age assessed by Hand-Wrist Radiographs

Directory of Open Access Journals (Sweden)

Kiran Sachan

2013-01-01

Conclusion: Females were more advanced in skeletal maturation than males. Chronological age showed inconsistent correlation with dental and skeletal ages. It was concluded that canine calcification stages can also be used for assessing skeletal maturity.

A Chronology of Late-Glacial and Holocene Advances of Quelccaya Ice Cap, Peru, Based on 10Be and Radiocarbon Dating

Science.gov (United States)

Kelly, M. A.; Lowell, T. V.; Schaefer, J. M.

2007-12-01

The Quelccaya Ice Cap region in the southeastern Peruvian Andes (~13-14°S latitude) is a key location for the development of late-glacial and Holocene terrestrial paleoclimate records in the tropics. We present a chronology of past extents of Quelccaya Ice Cap based on ~thirty internally consistent 10Be dates of boulders on moraines and bedrock as well as twenty radiocarbon dates of organic material associated with moraines. Based on results from both dating methods, we suggest that significant advances of Quelccaya Ice Cap occurred during late-glacial time, at ~12,700-11,400 yr BP, and during Late Holocene time ~400-300 yr BP. Radiocarbon dating of organic material associated with moraines provides maximum and minimum ages for ice advances and recessions, respectively, thus providing an independent check on 10Be dates of boulders on moraines. The opportunity to use both 10Be and radiocarbon dating makes the Quelccaya Ice Cap region a potentially important low-latitude calibration site for production rates of cosmogenic nuclides. Our radiocarbon chronology provides a tighter constraint on maximum ages of late-glacial and Late Holocene ice advances. Upcoming field research will obtain organic material for radiocarbon dating to improve minimum age constrains for late-glacial and Late Holocene ice recessions.

Multi-century long density chronology of living and sub-fossil trees from Lake Schwarzensee, Austria.

Science.gov (United States)

Kłusek, Marzena; Melvin, Thomas M; Grabner, Michael

This paper presents a multi-century, maximum latewood density (MXD) chronology developed from living and sub-fossil spruce trees from the Eastern Alps. The chronology is continuous from 88AD to 2008AD. This time series has been analysed with respect to its possible use for climate reconstruction. Correlations with climatic data showed strong dependence between MXD of growth rings and temperature of April, May, June, July, August and September and a weaker, negative dependence with precipitation of May and September. For solar radiation a positive relationship was noted for April, July, August and September. Light rings were frequently observed within the analysed samples and the climate of years with light rings was examined. Mean monthly temperatures in January, June, August, September and October, averaged during light ring years, were cooler than during years without light rings. Precipitation was also significantly reduced in March during light ring years. In turn, solar radiation during light ring years has significantly lowered values in February and August. The occurrence of light rings was often positively related to strong volcanic events.

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

International Nuclear Information System (INIS)

Sabil, N.

1995-06-01

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

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.

Influence of population versus convenience sampling on sample characteristics in studies of cognitive aging.

Science.gov (United States)

Brodaty, Henry; Mothakunnel, Annu; de Vel-Palumbo, Melissa; Ames, David; Ellis, Kathryn A; Reppermund, Simone; Kochan, Nicole A; Savage, Greg; Trollor, Julian N; Crawford, John; Sachdev, Perminder S

2014-01-01

We examined whether differences in findings of studies examining mild cognitive impairment (MCI) were associated with recruitment methods by comparing sample characteristics in two contemporaneous Australian studies, using population-based and convenience sampling. The Sydney Memory and Aging Study invited participants randomly from the electoral roll in defined geographic areas in Sydney. The Australian Imaging, Biomarkers and Lifestyle Study of Ageing recruited cognitively normal (CN) individuals via media appeals and MCI participants via referrals from clinicians in Melbourne and Perth. Demographic and cognitive variables were harmonized, and similar diagnostic criteria were applied to both samples retrospectively. CN participants recruited via convenience sampling were younger, better educated, more likely to be married and have a family history of dementia, and performed better cognitively than those recruited via population-based sampling. MCI participants recruited via population-based sampling had better memory performance and were less likely to carry the apolipoprotein E ε4 allele than clinically referred participants but did not differ on other demographic variables. A convenience sample of normal controls is likely to be younger and better functioning and that of an MCI group likely to perform worse than a purportedly random sample. Sampling bias should be considered when interpreting findings. Copyright © 2014 Elsevier Inc. All rights reserved.

ESR dating method and the age determination of Peking-Man

International Nuclear Information System (INIS)

Jin Sizhao; Liang Renyou; Huang Peihua

1991-01-01

ESR dating method and the age determination of the first skull of Zhoukoudian Beijing-Man have been introduced in this paper. Some animal fossil teeth, which are contemporaneous with the Beijing-Man, were used for determination of accumulative dose. The internal and environmental doses of the tooth samples were determined by neutron activation analysis and embeded thermoluminescence dosimeter at the site, respectively. The age of 578 ka of the first skull of Beijing-Man is calculated by the linear uranium accumulation model. According to the ESR dating results, author has given a chronological scale of the cave deposits Loc. 1, Beijing-man site and discussed the mean-life of trapped electron for dating

Visible Age-Related Signs and Risk of Ischemic Heart Disease in the General Population

DEFF Research Database (Denmark)

Christoffersen, Mette; Frikke-Schmidt, Ruth; Schnohr, Peter

2014-01-01

developed MI. Presence of frontoparietal baldness, crown top baldness, earlobe crease, and xanthelasmata was associated with increased risk of IHD or MI after multifactorial adjustment for chronological age and well-known cardiovascular risk factors. The risk of IHD and MI increased stepwise with increasing...... risk of IHD and MI increased with increasing number of visible age-related signs. CONCLUSIONS: Male pattern baldness, earlobe crease, and xanthelasmata-alone or in combination-associate with increased risk of ischemic heart disease and myocardial infarction independent of chronological age and other...

Radiocarbon dating, chronologic framework, and changes in accumulation rates of holocene estuarine sediments from Chesapeake Bay

Science.gov (United States)

Colman, Steven M.; Baucom, P.C.; Bratton, J.F.; Cronin, T. M.; McGeehin, J.P.; Willard, D.; Zimmerman, A.R.; Vogt, P.R.

2002-01-01

Rapidly accumulating Holocene sediments in estuaries commonly are difficult to sample and date. In Chesapeake Bay, we obtained sediment cores as much as 20 m in length and used numerous radiocarbon ages measured by accelarator mass spectrometry methods to provide the first detailed chronologies of Holocene sediment accumulation in the bay. Carbon in these sediments is a complex mixture of materials from a variety of sources. Analyses of different components of the sediments show that total organic carbon ages are largely unreliable, because much of the carbon (including coal) has been transported to the bay from upstream sources and is older than sediments in which it was deposited. Mollusk shells (clams, oysters) and foraminifera appear to give reliable results, although reworking and burrowing are potential problems. Analyses of museum specimens collected alive before atmospheric nuclear testing suggest that the standard reservoir correction for marine samples is appropriate for middle to lower Chesapeake Bay. The biogenic carbonate radiocarbon ages are compatible with 210 Pb and 137 Cs data and pollen stratigraphy from the same sites. Post-settlement changes in sediment transport and accumulation is an important environmental issue in many estuaries, including the Chesapeake. Our data show that large variations in sediment mass accumulation rates occur among sites. At shallow water sites, local factors seem to control changes in accumulation rates with time. Our two relatively deep-water sites in the axial channel of the bay have different long-term average accumulation rates, but the history of sediment accumulation at these sites appears to reflect overall conditions in the bay. Mass accumulation rates at the two deep-water sites rapidly increased by about fourfold coincident with widespread land clearance for agriculture in the Chesapeake watershed.

DNA damage: A main determinant of vascular aging

NARCIS (Netherlands)

P.K. Bautista-Niño (Paula); E. Portilla-Fernandez (Eliana); D.E. Vaughan (Douglas E.); A.H.J. Danser (Jan); A.J.M. Roks (Anton)

2016-01-01

textabstractVascular aging plays a central role in health problems and mortality in older people. Apart from the impact of several classical cardiovascular risk factors on the vasculature, chronological aging remains the single most important determinant of cardiovascular problems. The causative

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

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

Science.gov (United States)

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

2013-01-01

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

Dental Age Difference in Children with ADHD.

Science.gov (United States)

Wadhwa, Puneet; Yu, Qingzhao; Zhu, Han; Townsend, Janice A

2018-01-01

The purpose of this study was to determine if changes in dental development are associated with Attention Deficit Hyperactivity Disorder (ADHD) or ADHD medications. This retrospective chart review evaluated the dental age of 128 patients between 6 and 16 years of age using the Demirjian method from the following two groups a) children with ADHD b) unaffected children. The ADHD group was further stratified into four groups according to the medication type. The impact of ADHD on dental age difference (the difference between dental age and chronologic age) was analyzed using T-test and the association between medication type and dental age difference was analyzed through one way ANOVA. The mean difference between estimated dental age and chronologic age (dental age difference) for all subjects was 0.80 years. There was no significant dental age difference in subjects with ADHD and the control group (0.78±1.28vs. 0.84 ±1.09 years respectively; P=0.75) and there was no significant difference in dental age difference and type of medication (P=0.84). No significant difference was found between children with ADHD and unaffected children with respect to dental age difference. No significant differences were found in dental age difference in the four medication groups.

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

Understanding the climate mechanisms requires a precise knowledge of the sequence of events during major climate changes. In order to provide precise relationships between changes in orbital and/or greenhouse gases concentration forcing, sea level changes and high vs low latitudes temperatures, a common chronological framework for different paleoclimatic archives is required. Coherent chronologies for ice cores have been recently produced using a bayesian dating tool, DATICE (Lemieux-Dudon et al., 2010, Bazin et al., 2013, Veres et al., 2013). Such tool has been recently developed to include marine cores and speleothems in addition to ice cores. This new development should enable one to test the coherency of different chronologies using absolute and stratigraphic links as well as to provide relationship between climatic changes recorded in different archives. We present here a first application of multi-archive coherent dating including paleoclimatic archives from (1) Greenland (NGRIP ice core), (2) Mediterranean sea (marine core MD90-917, 41° N17° E, 1010 m) and (3) speleothems from the South of France and North Tunisia (Chauvet, Villars and La Mine speleothems, Genty et al., 2006). Thanks to the good absolute chronological constraints from annual layer counting in NGRIP, 14C and tephra layers in MD90-917 and U-Th dating in speleothems, we can provide a precise chronological framework for the last 50 ka (ie. thousand years before present). Then, we present different tests on how to combine the records from the different archives and give the most plausible scenario for the sequence of events at different latitudes over the last deglaciation. Bazin, L., Landais, A. ; Lemieu¬-Dudon, B. ; Kele, H. T. M. ; Veres, D. ; Parrenin, F. ; Martinerie, P. ; Ritz, C. ; Capron, E. ; Lipenkov, V. ; Loutre, M.-F. ; Raynaud, D. ; Vinther, B. ; Svensson, A. ; Rasmussen, S. ; Severi, M. ; Blunier, T. ; Leuenberger, M. ; Fischer, H. ; Masson-¬-Delmotte, V. ; Chappellaz, J

The Creation of the world and the birth of chronology

Science.gov (United States)

Richet, Pascal

2017-09-01

The eternity of the world and, correlatively, the cyclical nature of time were agreed upon by all Greek philosophical schools except the Platonists. As for matter, all of them posited that it was eternal so that the idea that something could be made from nothing was considered as pure absurdity. With the advent of Christianity, however, a matter coeternal with God raised fundamental theological difficulties. Toward the end of the second century, apologists such as Tatian the Assyrian, Theophilus of Antioch, Irenaeus of Lyons or Tertullian thus emphasized God's absolute freedom and power by claiming that Creation had been made from nothing. Along with the Passion of Christ and the Last Judgment, the initial moment defined by the Creation then conferred to time an irreversible, linear orientation and to history both a new sense and an obsessing concern for chronology. Unambiguously, the Creation became the reference point for the world's history. From Scripture analyses, one determined that it took place about 5500 years earlier within a framework where the History of man and that of the earth were not distinct. Having designed a consistent, universal time scale from chronological data recorded for all ancient peoples, Eusebius of Caesarea could thus attribute to the Great Flood the fossils found on the top of Mount Lebanon. The short Mosaic chronologies were eventually rejected during the 18th century, but Eusebius' chronological procedure was unknowingly transposed when a relative geological timescale was then set up from the fossil record. The close association of Creation with Christian dogma in turn induced some circles to reject the second law of thermodynamics at the end of the 19th century and, a few decades later, the thesis of an expanding universe. In both cases, the reason was that continuously increasing entropy would imply some low-entropy initial state akin to a Creation.

Last Glacial Maximum and Lateglacial in the Polish High Tatra Mountains - Revised deglaciation chronology based on the 10Be exposure age dating

Science.gov (United States)

Makos, Michał; Rinterknecht, Vincent; Braucher, Régis; Tołoczko-Pasek, Anna; Arnold, Maurice; Aumaître, Georges; Bourlès, Didier; Keddadouche, Karim; Aster Team

2018-05-01

Deglaciation chronology of the Polish High Tatra Mountains has been reconstructed based on 10Be exposure age dating. Fifty-seven rock samples were collected from boulders located on the terminal and lateral moraines that limit the horizontal extent of the LGM and the Lateglacial glaciers in the Biała Woda and Sucha Woda catchments. The uncertainty-weighted mean age of 21.5 ± 2.5 ka obtained for the maximum terminal moraine in the Sucha Woda Valley indicates that the oldest preserved moraines were formed during the global LGM. The age population ranges between 15.1 ± 1.0 and 28.3 ± 2.0 ka, and suggests that glaciers reached their maximum position (LGM I) as early as 28-25 ka and the final stabilization of the form occurred much later possibly after melting of buried dead ice. The younger glacial oscillation (LGM II) occurred no later than 20.5 ka and is represented by well-preserved termino-lateral moraine systems in the Pańszczyca Valley. The first Lateglacial stage (LG1) in the study area is documented in the Rybi Potok Valley at the RP1 moraine (1300 m a.s.l.), which was stable at around 16.6 ± 0.3 ka. The younger LG2 stage has no defined absolute age, however, it is constrained between 16.5 and 15.5 ka by the timing of the LG3 stage. This cold event is represented by well-formed moraines in the Roztoka/Pięć Stawów Polskich, Rybi Potok and Pańszczyca valleys of which exposure age indicates their deposition between 15.0 ± 0.5 and 15.6 ± 0.1 ka. The LG1, LG2 and LG3 stages likely occurred during the Oldest Dryas cold stage (Greenland Stadial 2.1a) related to the North Atlantic cooling Heinrich Event 1. The youngest glacial oscillation is evidenced by moraines in the Pusta and Pańszczyca valleys. These moraines are composed of very large granitic blocks of which exposure ages often exhibit isotope inheritance. This is reflected by the youngest P3 moraine in the Pańszczyca Valley with a mean age of deposition close to the LGM. The R4 moraine system in

Subjective age and personality development: a 10-year study.

Science.gov (United States)

Stephan, Yannick; Sutin, Angelina R; Terracciano, Antonio

2015-04-01

Personality theory and research typically focus on chronological age as a key indicator of personality development. This study examines whether the subjective experience of age is an alternative marker of the biomedical and psychosocial factors that contribute to individual differences in personality development. The present study uses data from the Midlife in the United States longitudinal survey (N = 3,617) to examine how subjective age is associated with stability and change in personality and the dynamic associations between subjective age and personality traits over a 10-year period. Regression analyses indicated that a younger subjective age at baseline was associated with increases in Openness, Conscientiousness, and Agreeableness; correlated changes were also found. The rank-order stability of Extraversion and Openness and overall profile consistency were higher among those with a younger subjective age at baseline and were also associated with the rate of subjective aging over time. The present study reveals that beyond chronological age, the age an individual feels is related to changes in characteristic ways of thinking, feeling, and behaving over time. © 2014 Wiley Periodicals, Inc.

Coronal pulp biomarker: A lesser known age estimation modality

Directory of Open Access Journals (Sweden)

Smrithi D Veera

2014-01-01

Full Text Available Introduction: The evolving state of art digital technology currently available is opening new avenues in forensic odontology for age estimation methods which are subject to debate in terms of accuracy and precision. A study was carried to analyze efficacy and practical application for age estimation using digital panoramic radiographs on South Indian population. Aims and Objectives: 1. To study reduction of coronal pulp chamber using Tooth Coronal Index (TCI on panoramic radiographs and correlate with chronologic age. 2. To establish accuracy of digital panoramic radiographs as a simple, non-invasive tool. Materials and Methods: The study illustrates the potential value of a little known aging method. The study groups comprised a total of 100 subjects of both sexes in age range of 20 and 60 years each who were subjected to panoramic radiography. A panoramic radiographic examination using digital panoramic machine was conducted on selected individuals. The TCI was calibrated using AGFA computer software for accuracy and precision. The values obtained were subjected to regression analysis, results calculated and correlated with chronologic age. In the present study a population of known age was studied and subjected to digital panoramic radiographic examination. The correlation between reduction of coronal pulp cavity and chronological age was examined. TCI was computed for each tooth and regressed on real age. Statistical Analysis Used: Pearson correlation co-efficient was used to find the significance of relationship between age and TCI. Regression analysis has been used for predicting age using TCI for premolar and molar. Inaccuracy and bias have been determined to assess the precision of prediction equations. Results and Conclusion: Prediction potential of TCI comes down for ages above 50 years and is comfortably good below 50 years without much difference between premolars and molars. This study demonstrates the potential value of TCI for age

Astronautics and aeronautics, 1972. [a chronology of events

Science.gov (United States)

1974-01-01

Important events of the U. S. space program during 1972 are recorded in a chronology which encompasses all NASA, NASA related, and international cooperative efforts in aeronautics and astronautics. Personnel and budget concerns are documented, along with the major developments in aircraft research, manned space flight, and interplanetary exploration.

Chronology of the cave interior sediments at Gran Dolina archaeological site, Atapuerca (Spain)

Science.gov (United States)

Parés, J. M.; Álvarez, C.; Sier, M.; Moreno, D.; Duval, M.; Woodhead, J. D.; Ortega, A. I.; Campaña, I.; Rosell, J.; Bermúdez de Castro, J. M.; Carbonell, E.

2018-04-01

The so-called "Gran Dolina site" (Atapuerca mountain range, N Spain) is a karstic cavity filled by sediments during the Pleistocene, some of which contain a rich ensemble of archaeological and paleontological records. These sediments have contributed significantly to our understanding of early human dispersal in Europe but, in contrast, older, interior facies deposits have received much less of attention. The stratigraphy of Gran Dolina reveals an abrupt sedimentary change of interior to entrance facies from bottom to top, reflecting a significant paleoenvironmental change that promoted the accumulation of sediments transported from the vicinity of the cave by water or "en masse". Since the major magnetic polarity reversal known as the Matuyama-Brunhes boundary (0.78 Ma) was detected within the TD7 unit in the middle of the stratigraphic section, we carried out a new combined paleomagnetic, radiometric (U-Pb), and electron spin resonance (ESR) dating study of the lower part of the sequence in order to constrain the chronology of the interior facies at Gran Dolina. U-Pb analysis of speleothems did not produce age information as the samples proved to be extremely unradiogenic. The magnetic stratigraphy of the cave interior sediments reveals a dominant reverse magnetic polarity, coherent with a Matuyama age, and interrupted by a normal polarity magnetozone interpreted as the Jaramillo Subchron (1.0-1.1 Ma). ESR ages on quartz grains from the upper part of the interior facies sediments are coherent with such an interpretation. We conclude that the fluvial deposits (interior facies) that constitute the cave floor began accumulating before 1.2 Ma. The development of large cave entrances at Gran Dolina occurred shortly after the Jaramillo Subchron but before ca 900 ka ago.

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.

Precise chronology of differentiation of developing human primary dentition.

Science.gov (United States)

Hu, Xuefeng; Xu, Shan; Lin, Chensheng; Zhang, Lishan; Chen, YiPing; Zhang, Yanding

2014-02-01

While correlation of developmental stage with embryonic age of the human primary dentition has been well documented, the available information regarding the differentiation timing of the primary teeth was largely based on the observation of initial mineralization and varies significantly. In this study, we aimed to document precise differentiation timing of the developing human primary dentition. We systematically examined the expression of odontogenic differentiation markers along with the formation of mineralized tissue in each developing maxillary and mandibular teeth from human embryos with well-defined embryonic age. We show that, despite that all primary teeth initiate development at the same time, odontogenic differentiation begins in the maxillary incisors at the 15th week and in the mandibular incisors at the 16th week of gestation, followed by the canine, the first primary premolar, and the second primary premolar at a week interval sequentially. Despite that the mandibular primary incisors erupt earlier than the maxillary incisors, this distal to proximal sequential differentiation of the human primary dentition coincides in general with the sequence of tooth eruption. Our results provide an accurate chronology of odontogenic differentiation of the developing human primary dentition, which could be used as reference for future studies of human tooth development.

Does a one year age gap modify the influence of age, maturation and anthropometric parameters as determinants of performance among youth elite soccer players?

Science.gov (United States)

Bidaurrazaga-Letona, Iraia; Lekue, José Antonio; Amado, Markos; Gil, Susana Maria

2017-08-22

Since age-groups in soccer often comprise children born within a two-year timeframe, characteristics that define the profile of a successful player may not be appropriate for the oldest or youngest players of the same age group. Therefore, this study aimed to determine to what extent performance was influenced by age, maturation and body size in elite soccer players with barely one year age gap. Anthropometry, 15-m sprint test, modified Barrow´s agility test, Yo-Yo intermittent recovery test level 1, countermovement jump, and handgrip test were conducted in players aged twelve and under (n=82, 11.1 ± 0.6 years; Mean ± SD) and between twelve and thirteen (n=79, 12.8 ± 0.6 years; Mean ± SD). A total score of performance, chronological age and age at peak height velocity were calculated. Descriptive statistics, Student's t-tests, and multiple linear regressions were performed. The explained variance in composite score was greater in the older (54%) than in the younger (30%) players. Sum of skinfolds was the primary predictor of 15-m sprint and countermovement jump in the younger group whereas in the older group chronological age and body size appeared as predictors of performance (41%). Body size explained the variance in most tests in older players. In the younger group biological maturity status explained the variance in endurance (35%) and handgrip (59%) tests. In summary, chronological age and sum of skinfolds influenced most tests; however, predictors differed between age groups. These findings highlight the importance of assessing individual differences in young male soccer players regardless of their similarity in age.

Fallout isotope chronology of the near-surface sediment record of Lake Bolătău.

Science.gov (United States)

Bihari, Árpád; Karlik, Máté; Mîndrescu, Marcel; Szalai, Zoltán; Grădinaru, Ionela; Kern, Zoltán

2018-01-01

Fallout isotope ( 210 Pb ex, 137 Cs and 241 Am) based dating has been carried out on the near-surface sediment core collected from Lake Bolătău-Feredeu (Bukovina, Romania). The motivation was to improve the chronology of this recent section in connection with significant fluctuations observed in sediment accumulation rates, particle size distribution and primordial radioisotope (i.e. 40 K and 232 Th) composition. Previously only an extrapolation of a broad-range OxCal age-depth model, which was based on 8 AMS radiocarbon dates from the deeper part of a parallel sediment sequence and tentatively validated for the upper part using the double peaks of the 137 Cs activity concentration distribution, was available for the studied section (1-24 cm). Parallel to the previous 137 Cs measurement, 210 Pb and 226 Ra (for a more detailed, 210 Pb ex -based chronology), 241 Am (for an additional time-marker), as well as 40 K and 232 Th concentrations have also been determined by gamma-spectrometry. In case of the 210 Pb ex -based chronology, due to a large deviation from a pure exponential distribution, the Constant Flux (CF) model has been used for the calculation of sediment ages and accumulation rates. Although the broad-range OxCal and the CF model were broadly similar down to 22 cm, the 210 Pb ex -based ages are clearly superior in terms of uncertainty in the uppermost 12 cm, while the broad-range model has smaller uncertainty below 20 cm (>150 years). The CF model gave an average mass accumulation rate of (0.08 ± 0.03) g cm -2 yr -1 for sections 0-11 cm, and (0.03 ± 0.01) g cm -2 yr -1 for sections 12-22 cm, respectively. Significant changes have been observed in the depth distribution of both the particle size distribution and the elemental/isotopic composition of the sediment record, most likely related to the variation observable in the intensity and volume of precipitation in the catchment. The obtained high-resolution records of Lake Bolătău, including

Appendix 2: Chronology of events

International Nuclear Information System (INIS)

Anon.

1988-01-01

The accident at the Chernobyl nuclear power plant and its consequences are set in chronological order from April 1986 to March 1988. The loss of confidence in nuclear power is clearly shown in the list of withdrawal or cancellations of reactor orders, especially those soon after the accident. Levels of radioactivity in food monitored in the UK and Europe is also listed. The International Atomic Energy Agency's Conventions on early notification and assistance and similar agreements to improve nuclear safety are included. The list is selective and includes both positive and negative consequences of the accident. (U.K.)

System Models and Aging: A Driving Example.

Science.gov (United States)

Melichar, Joseph F.

Chronological age is a marker in time but it fails to measure accurately the performance or behavioral characteristics of individuals. This paper models the complexity of aging by using a system model and a human function paradigm. These models help facilitate representation of older adults, integrate research agendas, and enhance remediative…

Eneolithic pile dwellings south of the Alps precisely dated with tree-ring chronologies from the north

OpenAIRE

Čufar, Katarina; Tegel, Willy; Merela, Maks; Kromer, Bernd; Velušček, Anton

2016-01-01

We present dendrochronological dating of Eneolithic pile dwellings on Ljubljansko barje, Slovenia, from the 4th millennium BC, partly included on the UNESCO world heritage list in 2011. Samples of oak (Quercus sp.) timbers from the posts on which the dwellings were built have been collected over the past 20 years. They have been dendrochronologically cross-dated and (pre) dated by 14C wiggle-matching. We describe the construction of a 442-year chronology BAR-3330 based on 106 cross-dated tree...

Age cohort differences in the developmental milestones of gay men.

Science.gov (United States)

Drasin, Harry; Beals, Kristin P; Elliott, Marc N; Lever, Janet; Klein, David J; Schuster, Mark A

2008-01-01

As the social context in which gay men live changes due to greater visibility, greater acceptance, and easier access to gay subculture, gay males may self-identify and take part in gay social activities at earlier ages than in the past. This study examined whether developmental milestones associated with sexual orientation for gay men have changed over the past several decades. A large and diverse sample of 2,402 gay men who responded to a 1994 survey published in a national magazine provided retrospective information on the age at which they reached individual psychological, social, and sexual behavior developmental milestones. We found evidence that individual psychological and sexual behavior milestones (e.g., awareness of attraction to males, having an orgasm with other male) are slowly moving toward earlier chronological ages (by 1 year of age every 8-25 years, p coming out) are moving more rapidly in a similar direction (by 1 year of age every 2-5 years, p < 0.001). The authors perform an innovative sensitivity test to demonstrate the persistence of the finding after correcting for the bias attributable to underrepresentation of those who have not yet self-identified as gay in such samples.

Perceptions of and Attitudes towards Ageing in Zambia

Science.gov (United States)

Mapoma, Christopher C.; Masaiti, Gift

2012-01-01

This paper reflects part of the wider outlook on ageing in general in Zambia and was intended to investigate perceptions of and attitudes towards the aged and ageing in Zambia by members of the community who, by definition and chronologically are not classified as aged i.e. not yet 60 years and over. Focus Group Discussions (FGD) were used to…

Age identity, self-rated health, and life satisfaction among older adults in Dakar, Senegal.

Science.gov (United States)

Macia, Enguerran; Duboz, Priscilla; Montepare, Joann M; Gueye, Lamine

2012-09-01

The objectives of this quantitative study were to (1) ascertain to what extent older adults aged 50 and above feel and desire to be younger than their age, and classify themselves as young versus old; (2) compare these patterns with those found among other cross-cultural populations; and (3) assess the extent to which self-rated health and life satisfaction predict age identities. This study was carried out on a sample of 500 dwellers of the Senegalese capital aged 50 and older. This sample was constructed using the quota method to strive for representativeness. Most of the respondents wanted to be younger than their chronological age (51.8 %), but only 27.8 % felt younger than they were. Moreover, 80 % of the sample claimed to be old. Self-rated health predicted felt age and the feeling of being old. Furthermore, the less-satisfied Dakar residents were with their life, the younger they wanted to be. We first discuss our results in a comparative perspective focused on how orientations toward individualism and collectivism could be related to age identity, and on demographic characteristics of the Senegalese population-where life expectancy is 59.3 years old. We then analyze the relevance of age identity dimensions as indicators of successful aging in Dakar.

Prematurity Affects Age of Presentation of Pyloric Stenosis.

Science.gov (United States)

Costanzo, Caitlyn M; Vinocur, Charles; Berman, Loren

2017-02-01

Term infants with hypertrophic pyloric stenosis (HPS) typically present between 4 and 6 weeks. There is limited consensus, however, regarding age of presentation of premature infants. We aim to determine if there is an association between the degree of prematurity and chronological age of presentation of HPS. A total of 2988 infants who had undergone a pyloromyotomy for HPS were identified from the 2012 and 2013 NSQIP-P Participant Use Files. Two hundred seventeen infants (7.3%) were born prematurely. A greater degree of prematurity was associated with an older chronological age of presentation ( P Prematurity was significantly associated with an increase in overall postoperative morbidity, reintubation, readmission, and postoperative length of stay. When clinicians evaluate an infant with nonbilious emesis with a history of prematurity, they should consider pyloric stenosis if the calculated postconceptional age is between 44 and 50 weeks. When counseling families of premature infants, surgeons should discuss the increased incidence of postpyloromyotomy morbidity.

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)

Jakni, B.

2000-01-01

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)

Chronology of the 1st–2nd Century Graves from the Tarasovo Burial Ground

Directory of Open Access Journals (Sweden)

Goldina Rimma D.

2016-03-01

Full Text Available The article focuses on the chronology of graves dating back to the early (1st – 2nd centuries AD – Nyrgynda stage of the 1st – 5th century Tarasovo burial ground, a classical monument attributed to the Cheganda culture of the Pyany Bor cultural-historical community. Cultural stratigraphy is applied as a research method. Artifacts from the early stage were correlated for 37 male and 102 female complexes, separately. The analysis of grave goods from male burials showed the following three chronological groups, that can be distinguished at the Nyrgynda stage: 1st century (group 1, 2nd century (group 2 and 1st – 2nd centuries AD (group 3. The goods from female graves are more representative and various, so three more groups with shorter chronological lives can be singled out: the fi rst half of the 2nd century (group 2а, the second half of the 2nd century (group 2б and the 1st – fi rst half of the 2nd century (group 4. Certainly, the suggested chronology leaves room for any eventual corrections subject to new findings.

Chronology of p53 protein accumulation in gastric carcinogenesis

NARCIS (Netherlands)

Craanen, M. E.; Blok, P.; Dekker, W.; Offerhaus, G. J.; Tytgat, G. N.

1995-01-01

p53 Protein accumulation in early gastric carcinoma was studied in relation to the histological type (Lauren classification) and the type of growth pattern, including the chronology of p53 protein accumulation during carcinogenesis. Forty five, paraffin embedded gastrectomy specimens from early

Ageing Drosophila selected for longevity retain a young gene expression profile

DEFF Research Database (Denmark)

Sarup, Pernille Merete

and longevity selected lines. Among the latter genes we found a clear overrepresentation of genes involved in immune functions supporting the hypothesis of the life shortening effect of an overactive immune system (inflammaging). Eighty-four genes were differentially expressed at the same physiological age...... between control and longevity selected lines, and the overlap between the same chronological and physiological age gene lists counted 40 candidate genes for increased longevity. Among these were genes with functions in starvation resistance, a regulator of immune responses and several genes which have......  We have investigated how the gene-expression profile of longevity selected lines of Drosophila melanogaster differed from control lines in young, middle-aged and old male flies. 530 genes were differentially expressed between selected and control flies at the same chronological age. We used...

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.

The End Is (Not) Near: Aging, Essentialism, and Future Time Perspective

Science.gov (United States)

Weiss, David; Job, Veronika; Mathias, Maya; Grah, Stephanie; Freund, Alexandra M.

2016-01-01

Beliefs about aging influence how we interpret and respond to changes within and around us. Essentialist beliefs about aging are defined as views that link chronological age with inherent and immutable properties underlying aging-related changes. These beliefs may influence the experience of aging-related changes and shape people's outlook of the…

Chronology of 3rd–5th Century Female Graves from Tarasovo Burial Ground

Directory of Open Access Journals (Sweden)

Goldina Rimma D.

2017-07-01

Full Text Available The article represents the concluding part a series of works by the authors on the dating of burials from the unique 1st–5th century Tarasovo burial ground in the Middle Kama region. The first article was dedicated to the chronology of graves dating back to the early Nyrgynda stage (1st–2nd centuries of this monument. The second and third publications feature an analysis of the chronology of 3rd–5th century male burials. The present work describes 160 female burials of 3rd–5th centuries analyzed from the perspective of chronology. Similarly to previous research, the three main methods employed by the authors of this research include those of formal typology, cultural stratigraphy and the nearest neighbour method. A total of 12 chronological groups were singled out as a result: 1st half of 3rd century A.D. (group 1; 2nd half of 3rd century (2; 3rd century (3; 4th century (group 4; 2nd half of 3rd–4th centuries (5а; 3rd–4th centuries (5б; 1st half of 5th century (6; 2nd half of 5th century (7; 5th century (group 8; 2nd half of 4th–5th centuries (9; 4th–5th centuries (10; 2nd half of 3rd–5th centuries

Differentiating the Influences of Aging and Adiposity on Brain Weights, Levels of Serum and Brain Cytokines, Gastrointestinal Hormones, and Amyloid Precursor Protein.

Science.gov (United States)

Banks, William A; Abrass, Christine K; Hansen, Kim M

2016-01-01

Aging and obesity exert important effects on disease. Differentiating these effects is difficult, however, because weight gain often accompanies aging. Here, we used a nested design of aged, calorically restricted, and refed rats to measure changes in brain and blood levels of cytokines and gastrointestinal hormones, brain amyloid precursor protein levels, and brain and body weights. By comparing groups and using path analysis, we found divergent influences of chronological aging versus body weight, our main findings being (i) changes in whole brain weight and serum macrophage colony-stimulating factor levels correlated better with body weight than with chronological aging, (ii) a decrease in brain cytokines and brain plasminogen activator inhibitor levels correlated better with chronological aging than with body weight, (iii) serum erythropoietin levels were influenced by both body weight and aging, (iv) serum plasminogen activator inhibitor, serum cytokines, and brain tumor necrosis factor were not influenced by aging or body weight, and (v) brain amyloid precursor protein more closely related to body weight and serum levels of gastrointestinal hormones than to brain weight, chronological aging, or cytokines. These findings show that although aging and body weight interact, their influences are distinct not only among various cytokines and hormones but also between the central nervous system and the peripheral tissue compartments. Published by Oxford University Press on behalf of the Gerontological Society of America 2014.

Age-related changes in the craniofacial region in a modern Greek population sample of known age and sex.

Science.gov (United States)

Chovalopoulou, Maria-Eleni; Bertsatos, Andreas; Papageorgopoulou, Christina

2017-07-01

The aim of this paper is to investigate ageing changes in craniofacial region in both sexes and evaluate whether these shape changes are substantial to achieve age discrimination of samples used in anthropological analyses. The study sample consisted of 157 crania of known sex and age (81 males and 76 females) belonging to individuals who lived in Greece during the twentieth century. The sample was divided in three age groups: young adults (YA, 18-39 years old), middle adults (MA, 40-59 years old) and old adults (OA, >60 years old). The three-dimensional coordinates of 31 ecto-cranial landmarks were digitized using a Microscribe 3DX contact digitizer, and landmark configurations were analyzed using the generalized least-squares Procrustes method. The results indicate that both males and females show significant difference among the age groups; however, shape differences can not be used for age group discrimination due to a large range on the accuracy of age group classification. The morphometric changes related to age were different between sexes.

Parity and age at menopause in a Danish sample

DEFF Research Database (Denmark)

Jeune, B

1986-01-01

A random sample of 151 Danish women who had undergone natural menopause reported the age at which this occurred and answered a questionnaire. A significant association was found between parity and age at menopause after correction for the effects of age at the first and last births, weight, smoking...... and occupation. However, there is no evidence that the age at menopause has fallen in recent decades, even though the average parity in developed populations has dropped dramatically over this period. It is therefore possible that potential fertility is a confounding variable in the relationship between parity...... and age at menopause....

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.

Age spans of some Indian speleothems

International Nuclear Information System (INIS)

Yadava, M.G.; Ramesh, R.; Polyak, V.J.; Asmerom, Y.

2009-01-01

In recent years, research on speleothems (minerals growing in caves, i.e. stalactites, stalagmites and flowstones) have shown that these have potential to provide records of past climate and environmental changes. Speleothems have several advantages compared to other high-resolution land archives (e.g., tree rings and lake sediments). Firstly, these are unaffected by natural erosion processes yielding long records of climate variability. Secondly, precise chronology by U-Th mass spectrometry is possible now. Prior to the advent of mass spectrometry (late 1980s), radiocarbon decay method was applied to date young samples (<40 kyr) and U-Th-alpha-counting method was adopted for older samples. In comparison with radiocarbon dates uranium series dates are absolute ages and no calibration is required. In India, palaeoclimate research using speleothem is in infancy, some work has been reported from Himalaya, central India and Peninsular India, with oxygen isotopes being used as monsoon proxy. Five speleothems from four Indian caves have been dated by U- Th method to estimate their ages and growth durations. Results indicate that these grew during various time intervals in Holocene and late Pleistocene

Chronological alterations of diagnostic imaging of renal cell carcinoma

International Nuclear Information System (INIS)

Arima, Kiminobu; Sugimura, Yoshiki; Yanagawa, Makoto; Tochigi, Hiromi; Kawamura, Juichi

1994-01-01

A review of 156 cases of renal cell carcinoma diagnosed during a 20-year period demonstrated the changes of initial signs/symptoms and imaging modalities for detection and definition. According to the imaging modality used for diagnosing renal cell carcinoma, clinical pictures were chronologically examined over 4 periods: 1973 to 1979 (before CT era), 1980 to 1984 (early CT era), 1985 to 1987 (CT era) and 1988 to 1992 (CT/MRI era). With regards to initial signs or symptoms, the proportion of classical trials has gradually decreased, while that of tumors noted incidentally has increased. As for imaging modalities for detection, the proportion of IVP has gradually decreased and that of CT and US has increased over the periods. With regard to imaging modalities for definition, the proportion of angiography has decreased and that of CT has increased. From chronological changes in clinical pictures and imaging modalities, we suggested a decision tree of imaging modalities for detection and definition of renal cell carcinoma. (author)

Aspartic acid racemization in dentin of the third molar for age estimation of the Chaoshan population in South China.

Science.gov (United States)

Chen, Shisheng; Lv, Yanyi; Wang, Dian; Yu, Xiaojun

2016-09-01

Aspartic acid racemization in teeth has been increasingly used to estimate chronological age with a considerably high accuracy in forensic practice. The Chaoshan population in South China is relatively isolated in geography, and has specific lifestyle and dietary inhibits. It is still unknown whether this method is suitable for this population. The aim of this study was to analyze the relationship between chronological age and the d/l aspartic acid ratio in dentin in the third molar tooth of the Chaoshan population. Fifty-eight non-carious third molar teeth (31 mandibles and 27 maxillae), from 58 living individuals of known age (24 males and 34 females), were retrieved. Dentin was extracted from these teeth. The d- and l-aspartic acids in dentins were separated and detected by high performance liquid chromatography (HPLC). Linear regression was performed between the d/l aspartic acid ratio of dentins and chronological age. Results showed that the correlation coefficient (r) was 0.969, and the mean absolute error (MAE) was 2.19 years, its standard deviation (SD) was ±1.53 years, indicating excellent correlation. There was no significant difference in racemization rates of dentin between sexes (P=0.113, F=2.6), or between mandibles and maxillae (P=0.964, F=0.000). Results indicate that the ratio of the d and l forms of aspartic acid of dentins, in the third molar, is closely correlated with chronological age, special lifestyle do no obviously affect the accuracy of the age estimations by aspartic acid racemization of the dentin in the third molar and that aspartic acid racemization in the third molar dentin can be used as an accurate method to estimate chronological age in the Chaoshan population in South China. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

An epigenetic biomarker of aging for lifespan and healthspan

Science.gov (United States)

Levine, Morgan E.; Lu, Ake T.; Quach, Austin; Chen, Brian H.; Assimes, Themistocles L.; Bandinelli, Stefania; Hou, Lifang; Baccarelli, Andrea A.; Stewart, James D.; Li, Yun; Whitsel, Eric A.; Wilson, James G; Reiner, Alex P; Aviv, Abraham; Lohman, Kurt; Liu, Yongmei; Ferrucci, Luigi

2018-01-01

Identifying reliable biomarkers of aging is a major goal in geroscience. While the first generation of epigenetic biomarkers of aging were developed using chronological age as a surrogate for biological age, we hypothesized that incorporation of composite clinical measures of phenotypic age that capture differences in lifespan and healthspan may identify novel CpGs and facilitate the development of a more powerful epigenetic biomarker of aging. Using an innovative two-step process, we develop a new epigenetic biomarker of aging, DNAm PhenoAge, that strongly outperforms previous measures in regards to predictions for a variety of aging outcomes, including all-cause mortality, cancers, healthspan, physical functioning, and Alzheimer's disease. While this biomarker was developed using data from whole blood, it correlates strongly with age in every tissue and cell tested. Based on an in-depth transcriptional analysis in sorted cells, we find that increased epigenetic, relative to chronological age, is associated with increased activation of pro-inflammatory and interferon pathways, and decreased activation of transcriptional/translational machinery, DNA damage response, and mitochondrial signatures. Overall, this single epigenetic biomarker of aging is able to capture risks for an array of diverse outcomes across multiple tissues and cells, and provide insight into important pathways in aging. PMID:29676998

Examining sources of bias in radiocarbon ages of New Zealand Kiore

Energy Technology Data Exchange (ETDEWEB)

Beavan, N.R.; Sparks, R.J. [Institute of Geological and Nuclear Sciences, (New Zealand). Rafter Radiocarbon Laboratory

1997-12-31

Recent AMS dates for the Pacific rat (Rattus exulans / Kiore) from natural and archaeological sites are significantly older than the generally accepted time for human arrival in New Zealand. Because Rattus exulans is recognized as a human commensal for Polynesian colonization in Oceania, radiocarbon ages for Kiore could be used as an indicator of earliest human contact with New Zealand. A strictly chronological interpretation of the radiocarbon ages assembled, though, raises serious questions about this arrival time. Therefore, factors that could affect the age determinations were also examined. A research programme in progress at the Rafter Radiocarbon Laboratory aims to identify the range and influence of natural bias and variance in radiocarbon ages in kiore bone samples. It was found that the main factors that could bias these ages were the incomplete removal of contaminants by the current bone preparation methods, and dietary carbon reservoir effects. Preliminary results of the various analytical techniques employed are presented.

Chronological narratives from smoking initiation through to pregnancy of Indigenous Australian women: A qualitative study.

Science.gov (United States)

Gould, Gillian S; Bovill, Michelle; Clarke, Marilyn J; Gruppetta, Maree; Cadet-James, Yvonne; Bonevski, Billie

2017-09-01

One in two Indigenous Australian pregnant women smoke, yet little is known about their trajectory of smoking. This study aimed to explore Aboriginal women's narratives from starting smoking through to pregnancy. A female Aboriginal Researcher conducted individual face-to-face interviews with 20 Aboriginal women from New South Wales, Australia. Recruitment, through Aboriginal services and community networks, continued until saturation was reached. Audio-recorded transcripts were independently open coded by two researchers, inductively analysed and reported using a three-dimensional structure of looking backwards, forwards, inwards, outwards and a sense of place, to elucidate the chronology of events, life stages, characters, environments, and turning points of the stories. A chronology emerged from smoking initiation in childhood, coming of age, becoming pregnant, through to attempts at quitting, and relapse post-partum. Several new themes emerged: the role mothers play in women's smoking and quitting; the contribution of nausea to spontaneous quitting; depression as a barrier to quitting; and the hopes of women for their own and their children's future. The epiphany of pregnancy was a key turning point for many - including the interplay of successive pregnancies; and the intensity of expressed regret. Aboriginal women report multiple influences in the progression of early smoking to pregnancy and beyond. Potential opportunities to intervene include: a) childhood, coming of age, pregnancy, post-natal, in-between births; b) key influencers; c) environments, and d) targeting concurrent substance use. Morning sickness appears to be a natural deterrent to continued smoking. Depression, and its relationship to smoking and quitting in Australian Indigenous pregnant women, requires further research. Copyright © 2017. Published by Elsevier Ltd.

Bone age assessment by digital images

International Nuclear Information System (INIS)

Silva, Ana Maria Marques da

1996-01-01

An algorithm which allows bone age assessment by digital radiological images was developed. For geometric parameters extraction, the phalangeal and metacarpal regions of interest are enhanced and segmented, through spatial and morphological filtering. This study is based on perimeter, length and area, from distal to proximal portions. The quantification of these parameters make possible comparison between chronological and skeletal age, using growth standard tables

Chronological production of thioacetamide-induced cirrhosis in the rat with no mortality.

Science.gov (United States)

Norasingha, Arthit; Pradidarcheep, Wisuit; Chayaburakul, Kanokporn

2012-01-01

Cirrhotic animal models are useful in studying complications of chronic liver disease. The authors chronologically investigated the effect of thioacetamide (TAA), administered intraperitoneally and adapted individually to weight changes, focusing on the optimal moment to obtain typical features of cirrhosis. Male Wistar Rats,150-200 g, were intoxicated three times per week with TAA of 200 mg/kg for 4, 8, 12 or 16 weeks (n = 8 per group), respectively and compared with age-matched controls (n = 4 per group). The individual body weight and liver function test were also measured in each group. Liver samples from each group were histologically stained with Sirius red in order to identify the degree of liver fibrosis. Rats intoxicated for 4, 8, 12 or 16 weeks had no mortality and histologically showed hepatitis and advanced fibrosis. At 12 and 16 weeks, all animals showed macronodular cirrhosis with signs of high-grade hepatocellular dysplasia. The weight of the treated groups at different time points was significantly lower than the controls. Routine liver function tests between cirrhotic and control rats showed significantly higher only in alanine transaminase (ALT) and aspartate aminotransferase (AST) at 8 and 12 weeks. However in the cirrhotic rats at 16 weeks, the ALT and AST were much lower than that at 8 and 12 weeks but did not show any difference from the controls. Thioacetamide, adapted to individual weight changes, leads to a model of cirrhosis in the rat at 12 and 16 weeks with zero mortality.

Age estimation by modified Demirjian's method (2004) and its applicability in Tibetan young adults: A digital panoramic study.

Science.gov (United States)

Bijjaragi, Shobha C; Sangle, Varsha A; Saraswathi, F K; Patil, Veerendra S; Ashwini Rani, S R; Bapure, Sunil K

2015-01-01

Estimation of the age is a procedure adopted by anthropologists, archeologists and forensic scientists. Different methods have been undertaken. However none of them meet the standards as Demirjian's method since 1973. Various researchers have applied this method, in both original and modified form (Chaillet and Demirjian in 2004) in different ethnic groups and the results obtained were not satisfactory. To determine the applicability and accuracy of modified Demirjian's method of dental age estimation (AE) in 8-18 year old Tibetan young adults to evaluate the interrelationship between dental and chronological age and the reliability between intra- and inter observer relationship. Clinical setting and computerized design. A total of 300 Tibetan young adults with an age range from 8 to 18 years were recruited in the study. Digital panoramic radiographs (DPRs) were evaluated as per the modified Demirjian's method (2004). Pearson correlation, paired t-test, linear regression analysis. Inter -and intraobserver reliability revealed a strong agreement. A positive and strong association was found between chronological age and estimated dental age (r = 0.839) with P < 0.01. Modified Demirjian method (2004) overestimated the age by 0.04 years (2.04 months)in Tibetan young adults. Results suggest that, the modified Demirjian method of AE is not suitable for Tibetan young adults. Further studies: With larger sample size and comparision with different methods of AE in a given population would be an interesting area for future research.

Handbook for Instruction on Aging in California Public Schools. Kindergarten Through Grade Twelve.

Science.gov (United States)

California State Dept. of Education, Sacramento.

This handbook is designed to assist teachers at the elementary and secondary level in the development of curricula on aging which can integrate the concepts of aging into ongoing lesson plans. The five content areas of instruction include chronological aging, physiological and biological aging, sociocultural aspects of aging, psychological aging,…

Age assessment of young asylum seekers

DEFF Research Database (Denmark)

Hjern, Anders; Brendler-Lindqvist, Maria; Nørredam, Marie Louise

2012-01-01

to be of real use in this decision. Unclear guidelines and arbitrary practices may lead to alarming shortcomings in the protection of this high-risk group of children and adolescents in Europe. Medical participation, as well as non-participation, in these dubious decisions raises a number of ethical questions....... CONCLUSION: To improve care for young asylum seekers with undetermined age, we suggest better legal procedures for the determination of age and a more flexible approach to chronological age....

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.

Age Differences in Personality: Evidence from a Nationally Representative Australian Sample

Science.gov (United States)

Lucas, Richard E.; Donnellan, M. Brent

2009-01-01

Cross-sectional age differences in the Big Five personality traits were examined in a nationally representative sample of Australians (N = 12,618; age range = 15-84). Extraversion, Neuroticism, and Openness were negatively associated with age, whereas Agreeableness and Conscientiousness were positively associated with age. Effect sizes comparing…

Coronary vascular age: An alternate means for predicting stress-induced myocardial ischemia in patients with suspected coronary artery disease.

Science.gov (United States)

Nappi, Carmela; Gaudieri, Valeria; Acampa, Wanda; Arumugam, Parthiban; Assante, Roberta; Zampella, Emilia; Mannarino, Teresa; Mainolfi, Ciro Gabriele; Imbriaco, Massimo; Petretta, Mario; Cuocolo, Alberto

2018-01-22

Coronary artery calcium (CAC) can be used to estimate vascular age in adults, providing a convenient transformation of CAC from Agatston units into a year's scale. We investigated the role of coronary vascular age in predicting stress-induced myocardial ischemia in subjects with suspected coronary artery disease (CAD). A total of 717 subjects referred to CAC scoring and 82 Rb PET/CT stress-rest myocardial perfusion imaging for suspected CAD were studied. CAC score was measured according to the Agatston method and coronary vascular age by equating estimated CAD risk for chronological age and CAC using the formula 39.1 + 7.25 × ln(CAC + 1). Stress-induced ischemia was present in 105 (15%) patients. Mean chronological age, CAC score, and coronary vascular age were higher (all P age was added to clinical variables. Including vascular age in the model, the global Chi square further increased from 68.77 to 106.38 (P age to clinical data, continuous net reclassification improvement (cNRI) was 0.57, while adding vascular age to clinical data and chronological age cNRI was 0.62. At decision curve analysis, the model including vascular age was associated with the highest net benefit compared to the model including only clinical data, to the model including chronological age and clinical data, and to a strategy considering that all patients had ischemia. The model including vascular age also showed the largest reduction in false-positive rate without missing any ischemic patients. In subjects with suspected CAD, coronary vascular age is strongly associated with stress-induced ischemia. The communication of a given vascular age would have a superior emotive impact improving observance of therapies and healthier lifestyles.

Prediction of mortality using on-line, self-reported health data: empirical test of the RealAge score.

Directory of Open Access Journals (Sweden)

William R Hobbs

Full Text Available OBJECTIVE: We validate an online, personalized mortality risk measure called "RealAge" assigned to 30 million individuals over the past 10 years. METHODS: 188,698 RealAge survey respondents were linked to California Department of Public Health death records using a one-way cryptographic hash of first name, last name, and date of birth. 1,046 were identified as deceased. We used Cox proportional hazards models and receiver operating characteristic (ROC curves to estimate the relative scales and predictive accuracies of chronological age, the RealAge score, and the Framingham ATP-III score for hard coronary heart disease (HCHD in this data. To address concerns about selection and to examine possible heterogeneity, we compared the results by time to death at registration, underlying cause of death, and relative health among users. RESULTS: THE REALAGE SCORE IS ACCURATELY SCALED (HAZARD RATIOS: age 1.076; RealAge-age 1.084 and more accurate than chronological age (age c-statistic: 0.748; RealAge c-statistic: 0.847 in predicting mortality from hard coronary heart disease following survey completion. The score is more accurate than the Framingham ATP-III score for hard coronary heart disease (c-statistic: 0.814, perhaps because self-reported cholesterol levels are relatively uninformative in the RealAge user sample. RealAge predicts deaths from malignant neoplasms, heart disease, and external causes. The score does not predict malignant neoplasm deaths when restricted to users with no smoking history, no prior cancer diagnosis, and no indicated health interest in cancer (p-value 0.820. CONCLUSION: The RealAge score is a valid measure of mortality risk in its user population.

Development of a Reference Data Set (RDS) for dental age estimation (DAE) and testing of this with a separate Validation Set (VS) in a southern Chinese population.

Science.gov (United States)

Jayaraman, Jayakumar; Wong, Hai Ming; King, Nigel M; Roberts, Graham J

2016-10-01

Many countries have recently experienced a rapid increase in the demand for forensic age estimates of unaccompanied minors. Hong Kong is a major tourist and business center where there has been an increase in the number of people intercepted with false travel documents. An accurate estimation of age is only possible when a dataset for age estimation that has been derived from the corresponding ethnic population. Thus, the aim of this study was to develop and validate a Reference Data Set (RDS) for dental age estimation for southern Chinese. A total of 2306 subjects were selected from the patient archives of a large dental hospital and the chronological age for each subject was recorded. This age was assigned to each specific stage of dental development for each tooth to create a RDS. To validate this RDS, a further 484 subjects were randomly chosen from the patient archives and their dental age was assessed based on the scores from the RDS. Dental age was estimated using meta-analysis command corresponding to random effects statistical model. Chronological age (CA) and Dental Age (DA) were compared using the paired t-test. The overall difference between the chronological and dental age (CA-DA) was 0.05 years (2.6 weeks) for males and 0.03 years (1.6 weeks) for females. The paired t-test indicated that there was no statistically significant difference between the chronological and dental age (p > 0.05). The validated southern Chinese reference dataset based on dental maturation accurately estimated the chronological age. Copyright © 2016 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

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.

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

Emotional complexity and its effect on psychological distress as a function of chronological age and subjective distance-to-death.

Science.gov (United States)

Shrira, Amit; Bodner, Ehud; Palgi, Yuval

2015-01-01

In light of mixed evidence regarding the associations between age, emotional complexity, and psychological distress, this study examined emotional complexity and its effect on psychological distress as a function of age and subjective distance-to-death. A sample of 188 participants (age range = 29-100) rated their subjective distance-to-death and psychological distress, and reported their emotions across 14 days. Emotional complexity was unrelated to age, but negatively related to feeling closer to death. Moreover, emotional complexity was negatively related to psychological distress among those feeling closer to death. Results suggest that when death is perceived to be nearer, emotional complexity is hampered, yet becomes relevant in buffering psychological distress.

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.

The biological age linked to oxidative stress modifies breast cancer aggressiveness.

Science.gov (United States)

Sáez-Freire, María Del Mar; Blanco-Gómez, Adrián; Castillo-Lluva, Sonia; Gómez-Vecino, Aurora; Galvis-Jiménez, Julie Milena; Martín-Seisdedos, Carmen; Isidoro-García, María; Hontecillas-Prieto, Lourdes; García-Cenador, María Begoña; García-Criado, Francisco Javier; Patino-Alonso, María Carmen; Galindo-Villardón, Purificación; Mao, Jian-Hua; Prieto, Carlos; Castellanos-Martín, Andrés; Kaderali, Lars; Pérez-Losada, Jesús

2018-03-14

The incidence of breast cancer increases with age until menopause, and breast cancer is more aggressive in younger women. The existence of epidemiological links between breast cancer and aging indicates that both processes share some common mechanisms of development. Oxidative stress is associated with both cancer susceptibility and aging. Here we observed that ERBB2-positive breast cancer, which developed in genetically heterogeneous ERBB2-positive transgenic mice generated by a backcross, is more aggressive in chronologically younger than in older mice (differentiated by the median survival of the cohort that was 79 weeks), similar to what occurs in humans. In this cohort, we estimated the oxidative biological age using a mathematical model that integrated several subphenotypes directly or indirectly related to oxidative stress. The model selected the serum levels of HDL-cholesterol and magnesium and total AKT1 and glutathione concentrations in the liver. The grade of aging was calculated as the difference between the predicted biological age and the chronological age. This comparison permitted the identification of biologically younger and older mice compared with their chronological age. Interestingly, biologically older mice developed more aggressive breast cancer than the biologically younger mice. Genomic regions on chromosomes 2 and 15 linked to the grade of oxidative aging were identified. The levels of expression of Zbp1 located on chromosome 2, a gene related to necroptosis and inflammation, positively correlated with the grade of aging and tumour aggressiveness. Moreover, the pattern of gene expression of genes linked to the inflammation and the response to infection pathways was enriched in the livers of biologically old mice. This study shows part of the complex interactions between breast cancer and aging. Copyright © 2018 Elsevier Inc. All rights reserved.

Advanced BrainAGE in older adults with type 2 diabetes mellitus

Directory of Open Access Journals (Sweden)

Katja eFranke

2013-12-01

Full Text Available Aging alters brain structure and function and diabetes mellitus (DM may accelerate this process. This study investigated the effects of type 2 DM on individual brain aging as well as the relationships between individual brain aging, risk factors and functional measures. To differentiate a pattern of brain atrophy that deviates from normal brain aging, we used the novel BrainAGE approach, which determines the complex multidimensional aging pattern within the whole brain by applying established kernel regression methods to anatomical brain MRIs. The Brain Age Gap Estimation (i.e., BrainAGE score was then calculated as the difference between chronological age and estimated brain age. 185 subjects (98 with type 2 DM completed an MRI at 3T, laboratory and clinical assessments. Twenty-five subjects (12 with type 2 DM also completed a follow-up visit after 3.8 ± 1.5 years. The estimated brain age of DM subjects was 4.6 ± 7.2 years greater than their chronological age (p = 0.0001, whereas within the control group, estimated brain age was similar to chronological age. As compared to baseline, the average BrainAGE scores of DM subjects increased by 0.2 years per follow-up year (p = 0.034, whereas the BrainAGE scores of controls did not change between baseline and follow-up. At baseline, across all subjects, higher BrainAGE scores were associated with greater smoking and alcohol consumption, higher tumor necrosis factor (TNFα levels, lower verbal fluency scores and more severe depression. Within the DM group, higher BrainAGE scores were associated with longer diabetes duration (r = 0.31, p = 0.019 and increased fasting blood glucose levels (r = 0.34, p = 0.025. In conclusion, type 2 DM is independently associated with structural changes in the brain that reflect advanced aging. The BrainAGE approach may thus serve as a clinically relevant biomarker for the detection of abnormal patterns of brain aging associated with type 2 DM.

Events of radioactive waste management - a chronological table

International Nuclear Information System (INIS)

1985-01-01

In chronological order the leaflet abstracted points out the essential data of German radioactive waste management. The data reach from December 1951 with EBR I (Idaho/USA) being the first one to feed electric power to the distribution grid to February 1985 known as the date of the submission of building applications for the first partial license of the Wackersdorf reprocessing plant. (HSCH) [de

U-Th ages obtained by mass spectrometry in corals from Barbados: sea level during the past 130,000 years

Energy Technology Data Exchange (ETDEWEB)

Bard, Edouard; Hamelin, Bruno; Fairbanks, R.G. (Columbia Univ., Palisades, NY (USA). Lamont-Doherty Geological Observatory)

1990-08-02

The study of the sea level record during the last glacial cycle has primarily proceeded indirectly by means of oxygen isotope measurements on foraminifera from deep-sea sediments. The direct approach of dating sea level indicators stagnated during the past decade, mainly because the samples required to complete our knowledge of the past glaciations are below the present-day sea level. Using the {sup 14}C ages of Acropora palmata samples collected by drilling offshore the island of Barbados, we report the first detailed chronology for the last deglaciation. This radio-carbon chronology is limited to the past 30 kyr because of the short half-life of {sup 14}C (5,730 yr); we must therefore rely on other dating methods to obtain information for the whole last glacial cycle. During the past four years {sup 230}Th-{sup 234}U dating of corals by thermal-ionization mass spectrometry has been shown to be significantly more precise and accurate than the classical {alpha}-counting method. We have used this technique to measure U-Th ages in coral samples from the Barbados collection and from subaerially exposed outcrops. Here we present results bearing on the sea level record for the past 130,000 years; we conclude that the last deglaciation started 3,000 years earlier than previously thought and confirm that there were two surges in melt water at about 11 kyr and 14 kyr BP (before present). (author).

U-Th ages obtained by mass spectrometry in corals from Barbados: sea level during the past 130,000 years

International Nuclear Information System (INIS)

Bard, Edouard; Hamelin, Bruno; Fairbanks, R.G.

1990-01-01

The study of the sea level record during the last glacial cycle has primarily proceeded indirectly by means of oxygen isotope measurements on foraminifera from deep-sea sediments. The direct approach of dating sea level indicators stagnated during the past decade, mainly because the samples required to complete our knowledge of the past glaciations are below the present-day sea level. Using the 14 C ages of Acropora palmata samples collected by drilling offshore the island of Barbados, we report the first detailed chronology for the last deglaciation. This radio-carbon chronology is limited to the past 30 kyr because of the short half-life of 14 C (5,730 yr); we must therefore rely on other dating methods to obtain information for the whole last glacial cycle. During the past four years 230 Th- 234 U dating of corals by thermal-ionization mass spectrometry has been shown to be significantly more precise and accurate than the classical α-counting method. We have used this technique to measure U-Th ages in coral samples from the Barbados collection and from subaerially exposed outcrops. Here we present results bearing on the sea level record for the past 130,000 years; we conclude that the last deglaciation started 3,000 years earlier than previously thought and confirm that there were two surges in melt water at about 11 kyr and 14 kyr BP (before present). (author)

Driving licences and medical screening in old age: Review of literature and European licensing policies

DEFF Research Database (Denmark)

Siren, Anu Kristiina; Haustein, Sonja

2015-01-01

Chronological age, per se, seems to be, in the case of mature drivers, only a weak predictor of safe driving performance. However, screening policies based on chronological age are widely used. Nevertheless, lately, more evidence-based policies have been called for. In this paper we first......, investigate the evidence for and against having an age-based driver screening policy in place; second, we map and compare the current driving licensing policies in European Union (EU) member states in order to examine the variation; and third, we draw conclusions based on the literature and the policy mapping...... are likely to limit the mobility and potentially worsen the safety of older persons....

Monthly paleostreamflow reconstruction from annual tree-ring chronologies

Science.gov (United States)

Stagge, J. H.; Rosenberg, D. E.; DeRose, R. J.; Rittenour, T. M.

2018-02-01

Paleoclimate reconstructions are increasingly used to characterize annual climate variability prior to the instrumental record, to improve estimates of climate extremes, and to provide a baseline for climate-change projections. To date, paleoclimate records have seen limited engineering use to estimate hydrologic risks because water systems models and managers usually require streamflow input at the monthly scale. This study explores the hypothesis that monthly streamflows can be adequately modeled by statistically decomposing annual flow reconstructions. To test this hypothesis, a multiple linear regression model for monthly streamflow reconstruction is presented that expands the set of predictors to include annual streamflow reconstructions, reconstructions of global circulation, and potential differences among regional tree-ring chronologies related to tree species and geographic location. This approach is used to reconstruct 600 years of monthly streamflows at two sites on the Bear and Logan rivers in northern Utah. Nash-Sutcliffe Efficiencies remain above zero (0.26-0.60) for all months except April and Pearson's correlation coefficients (R) are 0.94 and 0.88 for the Bear and Logan rivers, respectively, confirming that the model can adequately reproduce monthly flows during the reference period (10/1942 to 9/2015). Incorporating a flexible transition between the previous and concurrent annual reconstructed flows was the most important factor for model skill. Expanding the model to include global climate indices and regional tree-ring chronologies produced smaller, but still significant improvements in model fit. The model presented here is the only approach currently available to reconstruct monthly streamflows directly from tree-ring chronologies and climate reconstructions, rather than using resampling of the observed record. With reasonable estimates of monthly flow that extend back in time many centuries, water managers can challenge systems models with a

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.

Age and health jointly moderate the influence of flexible work arrangements on work engagement: Evidence from two empirical studies.

Science.gov (United States)

Rudolph, Cort W; Baltes, Boris B

2017-01-01

Research and theory support the notion that flexible work arrangements (i.e., job resources in the form of formal policies that allow employees the latitude to manage when, where, and how they work) can have a positive influence on various outcomes that are valued both by organizations and their constituents. In the present study, we integrate propositions from various theoretical perspectives to investigate how flexible work arrangements influence work engagement. Then, in 2 studies we test this association and model the influence of different conceptualizations of health and age as joint moderators of this relationship. Study 1 focuses on functional health and chronological age in an age-diverse sample, whereas study 2 focuses on health symptom severity and subjective age in a sample of older workers. In both studies, we demonstrate that the influence of flexible work arrangements on work engagement is contingent upon age and health. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

RELATIVE AND ABSOLUTE CHRONOLOGY OF YAMNAYA AND CATACOMB MONUMENTS THE ISSUE OF CO-EXISTENCE

OpenAIRE

Telegin, Dmitriy Y.; Pustovalov, Sergey Z.; Kovalyukh, Nikolay N.

2003-01-01

This volume of the Baltic-Pontic Studies is a record of investigations carried out under the research project begun earlier in vol. 7 ("The Foundations of radiocarbon chronology of cultures between the Vistula and Dnieper: 3150-1850 BC", Poznań 1999). Here, the approach is broader in terms of chronology and culture. Our purpose has been to fill taxonomic gaps hitherto present in the discussion (supplementing the dating of cultures, groups or phases) or reanalyze the grounds for findings consi...

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

D-galactose-induced animal model of male reproductive aging

OpenAIRE

Sulistyoningrum, Evy

2017-01-01

Aging is a complex biological process involving molecular, cellular and organic changes. Aging process is not merely caused by chronological age but it can be accelerated by environmental factors contributes to oxidative stress. Aging in male reproductive system is characterized by many conditions such as terticular atrophy, decreases testicular function of spermatogenesis, decreased testicular function of testosteron production which can lead to a serious clinical condition, infertility. Man...

Radiocarbon ages of upper quaternary deposit in central Nepal and their geomorphological significance

International Nuclear Information System (INIS)

Yamanaka, Hidetsugu

1982-01-01

The author visited Nepal from October, 1980, to February, 1981, investigated the geomorphology and upper Quaternary geology in Central Nepal, and collected a number of samples for radiocarbon dating. After returning to his university, he dated ten samples by himself. In Nepal, radiocarbon age has been scarcely reported as yet, besides in Kathmandu valley. Therefore, the author's ten data of the age are very important for the late Quaternary chronological study of Nepal Himalayas. In this paper, the author describes sampling localities and horizons, dating results and their geomorphological significance. These ten samples included Pokhara valley, Marsyandi Kohla, Modi Khola, Madi Khola and Muktinath samples. Some conclusion was derived as for the geomorphological development in central Nepal: The last Himalayan glacial age had already ended before 9,000 yr BP (years before A.D. 1950); In the Midland region, from 4,300 to 600 yr BP, some large-scale mudflows broke out nearly contemporaneously in the upper valleys, and they flowed down torrentially and catastrophically to deposit in the middle course of rivers. But the cause of vast quantity of material suddenly brought down from the Great Himalayas has been still left unexplained. The conclusion like this also was able to be applied to the middle Marsyandi Khola and the Pokhara valley. The wide-spread schema that the river was aggraded in the glacial age and degraded in the interglacial age may not be applicable to the rivers in the Midland region of Nepal Himalayas. (Wakatsuki, Y.)

The roles of chronological age and time perspective in memory positivity.

Science.gov (United States)

Kan, Irene P; Garrison, Shaina L; Drummey, Anna B; Emmert, Brian E; Rogers, Leeland L

2018-07-01

The observation that older adults show enhanced cognition for emotionally positive information has been labeled the positivity effect (Reed, Chan, & Mikels, 2014). According to the Socioemotional Selectivity Theory (SST, Carstensen, 1991), a prominent lifespan development theory, cognition is strongly influenced by motivational goals, and these goals are impacted by subjective time perspective. Although the positivity effect is most commonly observed in older adults, as age usually co-varies with time perspective, the SST posits that time perspective, not age, is the key explanatory factor of positivity. We examined the effects of these predictors on positivity in an episodic memory task in younger and older adults and found that age, not time perspective, was a key predictor of memory positivity. Our results add to the growing literature that challenge the notion that time perspective is the driving force behind age-related differences in emotional processing and functioning.

Does age impact self-actualization needs?—an empirical study ...

African Journals Online (AJOL)

Thus, although this study supports the existence of needs, the chronology of their dominance may not be as per Maslow's hierarchy pyramid. This empirical study establishes that there may not be progressive increase in self-actualization need as age progresses. Keywords: Maslow, need priorities, age, self-actualization ...

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.

Radiocarbon dating and wood density chronologies of mangrove trees in arid Western Australia.

Directory of Open Access Journals (Sweden)

Nadia S Santini

Full Text Available Mangrove trees tend to be larger and mangrove communities more diverse in tropical latitudes, particularly where there is high rainfall. Variation in the structure, growth and productivity of mangrove forests over climatic gradients suggests they are sensitive to variations in climate, but evidence of changes in the structure and growth of mangrove trees in response to climatic variation is scarce. Bomb-pulse radiocarbon dating provides accurate dates of recent wood formation and tree age of tropical and subtropical tree species. Here, we used radiocarbon techniques combined with X-ray densitometry to develop a wood density chronology for the mangrove Avicennia marina in the Exmouth Gulf, Western Australia (WA. We tested whether wood density chronologies of A. marina were sensitive to variation in the Pacific Decadal Oscillation Index, which reflects temperature fluctuations in the Pacific Ocean and is linked to the instrumental rainfall record in north WA. We also determined growth rates in mangrove trees from the Exmouth Gulf, WA. We found that seaward fringing A. marina trees (~10 cm diameter were 48 ± 1 to 89 ± 23 years old (mean ± 1 σ and that their growth rates ranged from 4.08 ± 2.36 to 5.30 ± 3.33 mm/yr (mean ± 1 σ. The wood density of our studied mangrove trees decreased with increases in the Pacific Decadal Oscillation Index. Future predicted drying of the region will likely lead to further reductions in wood density and their associated growth rates in mangrove forests in the region.

Chronological change of brain abscess in {sup 1}H magnetic resonance spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Akutsu, H.; Matsumura, A.; Isobe, T.; Takano, S.; Nose, T. [Department of Neurosurgery, Institute of Clinical Medicine, University of Tsukuba, Tennodai, Tsukuba, Ibaraki (Japan); Anno, I.; Itai, Y. [Department of Radiology, Institute of Clinical Medicine, University of Tsukuba, Tennodai, Tsukuba, Ibaraki (Japan)

2002-07-01

We studied chronological magnetic resonance spectral changes in brain abscesses before and after medical and/or surgical treatment. We examined five patients with MRI imaging and {sup 1}H magnetic resonance spectroscopy (MRS) on two or more occasions, using two volume-of-interest patterns, and saw chronological changes related to the evolution of the abscess. A spectrum specific for brain abscess was found in three of the five cases, while two showed a single lactate peak in the first study. In two cases, phenylalanine or alanine appeared in the second study. We observed the disappearance of the specific spectra and a single lactate peak following surgery. Only one patient showed different spectra in different volume of interest. (orig.)

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

Science.gov (United States)

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

2016-04-01

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

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.

Bayesian Optimization for Neuroimaging Pre-processing in Brain Age Classification and Prediction

Directory of Open Access Journals (Sweden)

Jenessa Lancaster

2018-02-01

Full Text Available Neuroimaging-based age prediction using machine learning is proposed as a biomarker of brain aging, relating to cognitive performance, health outcomes and progression of neurodegenerative disease. However, even leading age-prediction algorithms contain measurement error, motivating efforts to improve experimental pipelines. T1-weighted MRI is commonly used for age prediction, and the pre-processing of these scans involves normalization to a common template and resampling to a common voxel size, followed by spatial smoothing. Resampling parameters are often selected arbitrarily. Here, we sought to improve brain-age prediction accuracy by optimizing resampling parameters using Bayesian optimization. Using data on N = 2003 healthy individuals (aged 16–90 years we trained support vector machines to (i distinguish between young (<22 years and old (>50 years brains (classification and (ii predict chronological age (regression. We also evaluated generalisability of the age-regression model to an independent dataset (CamCAN, N = 648, aged 18–88 years. Bayesian optimization was used to identify optimal voxel size and smoothing kernel size for each task. This procedure adaptively samples the parameter space to evaluate accuracy across a range of possible parameters, using independent sub-samples to iteratively assess different parameter combinations to arrive at optimal values. When distinguishing between young and old brains a classification accuracy of 88.1% was achieved, (optimal voxel size = 11.5 mm3, smoothing kernel = 2.3 mm. For predicting chronological age, a mean absolute error (MAE of 5.08 years was achieved, (optimal voxel size = 3.73 mm3, smoothing kernel = 3.68 mm. This was compared to performance using default values of 1.5 mm3 and 4mm respectively, resulting in MAE = 5.48 years, though this 7.3% improvement was not statistically significant. When assessing generalisability, best performance was achieved when applying the entire Bayesian

Image analysis of the eruptive positions of third molars and adjacent second molars as indicators of age evaluation in Thai patients

Energy Technology Data Exchange (ETDEWEB)

Mahasantipiya, Phattaranant May; Pramojanee, Sakarat; Thaiupathump, Trasapong [Chiang Mai University, Chiang Mai (Thailand)

2013-12-15

This study was performed to determine the relationship between the stage of tooth eruption (both vertical and mesio-angular) and chronological age. Indirect digital panoramic radiographs were used to measure the distances from the dentinoenamel junction (DEJ) of the second molars to the occlusal plane of the second molar teeth and of the adjacent third molars in 264 Thai males and 437 Thai females using ImageJ software. The ratio of those distances was calculated by patient age, and the correlation coefficient of the ratio of the third molar length to the second molar length was calculated. The correlation between the height of the vertically erupted upper third molar teeth and age was at the intermediate level. The age range of ≥15 to <16 years was noted to be the range in which the correlation between the chronological age determined from the eruptional height and actual chronological age was statistically significant. The mean age of the female subjects, in which the position of the right upper third molar teeth was at or above the DEJ of the adjacent second molar but below one half of its coronal height was 19.9±2.6 years. That for the left side was 20.2±2.7 years. The mean ages of the male subjects were 20.1±3.3 years and 19.8±2.7 years for the right and left sides, respectively. It might be possible to predict chronological age from the eruption height of the wisdom teeth.

Image analysis of the eruptive positions of third molars and adjacent second molars as indicators of age evaluation in Thai patients

International Nuclear Information System (INIS)

Mahasantipiya, Phattaranant May; Pramojanee, Sakarat; Thaiupathump, Trasapong

2013-01-01

This study was performed to determine the relationship between the stage of tooth eruption (both vertical and mesio-angular) and chronological age. Indirect digital panoramic radiographs were used to measure the distances from the dentinoenamel junction (DEJ) of the second molars to the occlusal plane of the second molar teeth and of the adjacent third molars in 264 Thai males and 437 Thai females using ImageJ software. The ratio of those distances was calculated by patient age, and the correlation coefficient of the ratio of the third molar length to the second molar length was calculated. The correlation between the height of the vertically erupted upper third molar teeth and age was at the intermediate level. The age range of ≥15 to <16 years was noted to be the range in which the correlation between the chronological age determined from the eruptional height and actual chronological age was statistically significant. The mean age of the female subjects, in which the position of the right upper third molar teeth was at or above the DEJ of the adjacent second molar but below one half of its coronal height was 19.9±2.6 years. That for the left side was 20.2±2.7 years. The mean ages of the male subjects were 20.1±3.3 years and 19.8±2.7 years for the right and left sides, respectively. It might be possible to predict chronological age from the eruption height of the wisdom teeth.

A Chronologic Dual-Hemisphere Approach to the Last Glacial Termination from the Southern Alps of New Zealand and the Altai Mountains of Western Mongolia

Science.gov (United States)

Strand, P.; Putnam, A. E.; Schaefer, J. M.; Denton, G.; Barrell, D.; Putnam, D.; Schwartz, R.; Sambuu, O.; Radue, M. J.; Lindsay, B. J.; Stevens, J.

2017-12-01

Understanding the processes that drove the last glacial termination in the tropics and mid-latitudes is a major unresolved problem in paleoclimate. The most recent glacial to interglacial transition represents the last great global warming and the last time CO2 rose by a substantial amount before the industrial period. Determining the speed of this warming will help refine the global climate system sensitivity to CO2 and will place ongoing global warming into a paleoclimatic context. Here, we test possible drivers of the last glacial termination by comparing chronologies of mountain glaciers, which are highly sensitive to changes in atmospheric temperature, in the middle latitudes of both polar hemispheres. The dating of glacier landforms, such as moraine ridges constructed along glacier margins, affords quantitative insight into past climate conditions. We present 10Be surface-exposure chronologies and glacial geomorphologic maps of mountain glacier recession since the Last Glacial Maximum in the Southern Alps of New Zealand (44°S, 170°E) and in the Altai Mountains of western Mongolia (49°N, 88°E). On the basis of these chronologies from opposing hemispheres, we evaluate the relative roles of rising atmospheric CO2, local insolation forcing, and ocean-atmosphere reorganizations in driving the global warming that ended the last ice age.

An epigenetic clock for gestational age at birth based on blood methylation data

DEFF Research Database (Denmark)

Knight, Anna K.; Craig, Jeffrey M; Theda, Christiane

2016-01-01

BACKGROUND: Gestational age is often used as a proxy for developmental maturity by clinicians and researchers alike. DNA methylation has previously been shown to be associated with age and has been used to accurately estimate chronological age in children and adults. In the current study, we exam...

Precision and accuracy of commonly used dental age estimation charts for the New Zealand population.

Science.gov (United States)

Baylis, Stephanie; Bassed, Richard

2017-08-01

Little research has been undertaken for the New Zealand population in the field of dental age estimation. This research to date indicates there are differences in dental developmental rates between the New Zealand population and other global population groups, and within the New Zealand population itself. Dental age estimation methods range from dental development charts to complex biometric analysis. Dental development charts are not the most accurate method of dental age estimation, but are time saving in their use. They are an excellent screening tool, particularly for post-mortem identification purposes, and for assessing variation from population norms in living individuals. The aim of this study was to test the precision and accuracy of three dental development charts (Schour and Massler, Blenkin and Taylor, and the London Atlas), used to estimate dental age of a sample of New Zealand juveniles between the ages of 5 and 18 years old (n=875). Percentage 'best fit' to correct age category and to expected chart stage were calculated to determine which chart was the most precise for the sample. Chronological ages were compared to estimated dental ages using a two-tailed paired t-test (Pcharts tested against the New Zealand population sample, the Blenkin and Taylor Australian charts performed best overall. Copyright © 2017 Elsevier B.V. All rights reserved.

Investigating Discontinuity of Age Relations in Cognitive Functioning, General Health Status, Activity Participation, and Life Satisfaction between Young-Old and Old-Old Age.

Science.gov (United States)

Ihle, Andreas; Jopp, Daniela S; Oris, Michel; Fagot, Delphine; Kliegel, Matthias

2016-11-05

Health research suggests that findings on young-old adults cannot be generalized to old-old adults and thus that old-old age seems not a simple continuation of young-old age due to qualitative changes that result in a discontinuity in old age. Specifically, it would be of conceptual and methodological importance to inform research regarding estimates around which chronological age the beginning of old-old age could be placed at a population level, and whether this is universal or domain-specific. To derive such criteria, we investigated potential discontinuity of age relations between young-old and old-old age in a large population-based sample considering measures in different domains (processing speed, verbal abilities, general health status, activity participation, and life satisfaction). For processing speed, verbal abilities, general health status, and life satisfaction we observed some very small indication that there might be a discontinuity of age relations at the end of individuals' eighties, and for activity participation already at the beginning of individuals' eighties. In conclusion, models conceptualizing aging as a gradual development might not suffice to adequately represent the differences between the stages of young-old and old-old age due to some very small indication that there might be discontinuity in late adulthood.

Conceptualisation of ageing in relation to factors of importance for extending working life - a review.

Science.gov (United States)

Nilsson, Kerstin

2016-07-01

The aim of this study was to explore and understand the complexity of ageing in relation to factors of importance for extending working life. Discourse analysis of documents was used in an integrative review including 128 articles. Four different conceptualisation of ageing are shown to affect older workers' ability to extend their working life: (a) biological ageing people's health in relation to their physical and mental work environment, their pace of work and recuperation needs; (b) chronological ageing statutory retirement age and policies and economic incentives devised for older workers by society, unions and organisations/enterprises; (c) social ageing inclusion in different social groups, the attitude of managers, organisations and family members, the leisure activities and surrounding environment; and (d) mental/cognitive ageing self-crediting, motivating and meaningful activities, competence and skills in working life. CONCLUSIONS SOCIETIES TODAY FOCUS MOSTLY ON CHRONOLOGICAL AGEING AND ARE LOOKING TO INCREASE THE RETIREMENT AGE WITH REGARD TO STATUTORY PENSION SYSTEMS, EG BEYOND 65 YEARS OF AGE THE INTER-RELATIONSHIPS BETWEEN CHRONOLOGICAL, MENTAL, BIOLOGICAL AND SOCIAL AGEING AND THE NINE AREAS IDENTIFIED AS BEING IMPORTANT TO OLDER WORKERS IN THESE RESPECTS NEED TO BE CONSIDERED WHEN AIMING TO PROVIDE A SUSTAINABLE WORKING LIFE FOR THE INCREASING NUMBERS OF OLDER WORKERS IN MODERN SOCIETY THE THEORETICAL MODEL DEVELOPED IS A CONTRIBUTION TO THE CRITICAL DEBATE THAT CAN BE APPLIED BY SOCIETIES, EMPLOYERS AND MANAGERS IN ORDER TO PROVIDE OLDER WORKERS WITH AN INCLUSIVE AND SUSTAINABLE EXTENDED WORKING LIFE. © 2016 the Nordic Societies of Public Health.

DNA methylation age is associated with mortality in a longitudinal Danish twin study

DEFF Research Database (Denmark)

Christiansen, Lene; Lenart, Adam; Tan, Qihua

2016-01-01

included a 10-year longitudinal study of the 86 oldest-old twins (mean age of 86.1 at follow-up), which subsequently were followed for mortality for 8 years. We found that the DNAm age is highly correlated with chronological age across all age groups (r = 0.97), but that the rate of change of DNAm age...

A chronology of El niño events from primary documentary sources in northern Peru

OpenAIRE

García Herrera, Ricardo; Díaz, H. F.; García, R. R.; Prieto, M. R.; Barriopedro Cepero, David; Moyano, R.; Hernández Martín, Emiliano

2008-01-01

The authors present a chronology of El Niño (EN) events based on documentary records from northern Peru. The chronology, which covers the period 1550-1900, is constructed mainly from primary sources from the city of Trujillo (Peru), the Archivo General de Indias in Seville (Spain), and the Archivo General de la Nacion in Lima (Peru), supplemented by a reassessment of documentary evidence included in previously published literature. The archive in Trujillo has never been systematically evaluat...

Effects of sampling design on age ratios of migrants captured at stopover sites

Science.gov (United States)

Jeffrey F. Kelly; Deborah M. Finch

2000-01-01

Age classes of migrant songbirds often differ in migration timing. This difference creates the potential for age-ratios recorded at stopover sites to vary with the amount and distribution of sampling effort used. To test for these biases, we sub-sampled migrant capture data from the Middle Rio Grande Valley of New Mexico. We created data sets that reflected the age...

Astronautics and Aeronautics: A Chronology, 1996-2000

Science.gov (United States)

Lewis, Marieke; Swanson, Ryan

2009-01-01

This report is a chronological compilation of narrative summaries of news reports and government documents highlighting significant events and developments in United States and foreign aeronautics and astronautics. It covers the years 1996 through 2000. These summaries provide a day-by-day recounting of major activities, such as administrative developments, awards, launches, scientific discoveries, corporate and government research results, and other events in countries with aeronautics and astronautics programs. Researchers used the archives and files housed in the NASA History Division, as well as reports and databases on the NASA Web site.

Astronautics and Aeronautics: A Chronology, 2001-2005

Science.gov (United States)

Ivey, William Noel; Lewis, Marieke

2010-01-01

This report is a chronological compilation of narrative summaries of news reports and government documents highlighting significant events and developments in U.S. and foreign aeronautics and astronautics. It covers the years 2001 through 2005. These summaries provide a day-by-day recounting of major activities, such as administrative developments, awards, launches, scientific discoveries, corporate and government research results, and other events in countries with aeronautics and astronautics programs. Researchers used the archives and files housed in the NASA History Division, as well as reports and databases on the NASA Web site.

Absolute chronology and stratigraphy of Lepenski Vir

Directory of Open Access Journals (Sweden)

Borić Dušan

2007-01-01

radiometric dates from Lepenski Vir 21 made by the conventional 14C dating of charcoal and 8 AMS dates made on animal (3 dates and human bones (5 dates. There is also a series of 20 new AMS dates made on human bones from Lepenski Vir. The last group of dates has not been published with all the contextual details and are of limited use in our analyses of absolute chronology and stratigraphy of Lepenski Vir. New dates are listed in Table 1. From 32 dated contexts from Lepenski Vir, 27 contexts are stratigraphically related to trapezoidal buildings while 5 dates are connected with the area outside of buildings. From those contexts related to trapezoidal structures, 24 contexts are dated with animal and 3 with human bones. The emphasis on the dating of animal bones is connected with problems of precision when dating samples made on human and dog bones due to the reservoir effect and the deposition of 'old' carbon. Dated remains of animal and human bones originate from the following types of stratigraphic contexts a beneath building floors, i.e. stratigraphically the oldest contexts in the settlement (2 dates (Fig. 2; b between two superposed floors of trapezoidal buildings as 'sealed' contexts (8 dates (Fig. 3; c lying directly on top of the floors of trapezoidal buildings but not overlapped by a later floor (17 dates (Fig. 3; d outside of trapezoidal buildings, found in contexts such as pits, domed ovens, and burials, or in contexts that can be attributed to the occupation layer only (6 dates (Fig. 4. The new dates indicate a very long duration of the Mesolithic period, from around 9400 to around 7500 cal BC (Fig. 2, 23. These early dates are concentrated in two particular periods that may point to two separate phases within these two millennia, with settlement discontinuities. It remains possible that there were many more occupation episodes that these dates do not encompass, and more AMS dates may indicate whether these two groupings with three dates per grouping are

To Correct or Not to Correct: Age Adjustment for Prematurity.

Science.gov (United States)

Aylward, Glen P.; And Others

To evaluate whether conceptional or chronologic age should be used to determine scores in developmental follow-up studies, a study was made of 236 normal and 66 neurologically abnormal infants who were similar with respect to conceptional age but different with respect to degree of prematurity. Assessments of possible differences in cognitive and…

1995 Phase 1 concrete sampling at the decontaminated 183-H basins

International Nuclear Information System (INIS)

Kramer, C.D.

1996-01-01

This report provides a consolidated reference for 1995 concrete sampling data associated with the Hanford Site's 183-H Solar Evaporation Basins (located at the Hanford Site in Richland, Washington). In 1995, the basins were decontaminated and dismantled. Sampling efforts began after completion of concrete decontamination efforts. Soil and water samples were collected and are described in chronological order in this report

Quantitative measures of healthy aging and biological age

Science.gov (United States)

Kim, Sangkyu; Jazwinski, S. Michal

2015-01-01

Numerous genetic and non-genetic factors contribute to aging. To facilitate the study of these factors, various descriptors of biological aging, including ‘successful aging’ and ‘frailty’, have been put forth as integrative functional measures of aging. A separate but related quantitative approach is the ‘frailty index’, which has been operationalized and frequently used. Various frailty indices have been constructed. Although based on different numbers and types of health variables, frailty indices possess several common properties that make them useful across different studies. We have been using a frailty index termed FI34 based on 34 health variables. Like other frailty indices, FI34 increases non-linearly with advancing age and is a better indicator of biological aging than chronological age. FI34 has a substantial genetic basis. Using FI34, we found elevated levels of resting metabolic rate linked to declining health in nonagenarians. Using FI34 as a quantitative phenotype, we have also found a genomic region on chromosome 12 that is associated with healthy aging and longevity. PMID:26005669

Time and Chronology in Modern Novels: An Example of Woolf and ...

African Journals Online (AJOL)

Time and Chronology in Modern Novels: An Example of Woolf and Joyce. ... It is in this context that this article attempts to provide a brief survey of two modern ... the displacement feature of language to defamiliarize our conception of time and

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)

Balescu, S.; Lamothe, M.; Coque-Delhuille, B.

1998-01-01

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 14 C. 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 14 C datable material is rare. (authors)

Ice age plant refugia in East Greenland

DEFF Research Database (Denmark)

Funder, Svend Visby

1979-01-01

From the distribution of plants it has been inferred by some botanists that ice-free areas existed in East Greenland accommodating a flora which survived one or several ice ages in the area. Comparing this evidence with recent information on the chronology of glaciations and post-glacial vegetation...

The age of the galactic disk

International Nuclear Information System (INIS)

Clayton, D.D.

1989-01-01

This paper presents arguments suggesting that the best estimate of the age of the galaxy is 12 G < 16 Gyr. The author has emphasized the theoretical closeness of nuclear chronology to a correct and detailed description of the evolution of stars and of the galaxy itself. Nuclear cosmochronology does not stand alone as a technique for age determination. Conventional old-fashioned astronomy is at least as important, as is the detailed distribution of histories of astrated matter

Age estimation using development of third molars in South Indian population: A radiological study.

Science.gov (United States)

Priyadharshini, K Indra; Idiculla, Jose Joy; Sivapathasundaram, B; Mohanbabu, V; Augustine, Dominic; Patil, Shankargouda

2015-05-01

To assess the estimation of chronological age based on the stages of third molar development following the eight stages (A-H) method of Demirjian et al. in Chennai population of South India. A sample consisting of 848 individuals (471 males and 377 females) aged between 14 and 30 years was randomly selected for the clinical evaluation and 323 orthopantomograms with clinically missing third molars were taken for radiological evaluation using Demirjian's method from a Chennai population of known chronological age and sex. Statistical analysis was performed using Pearson's Chi-square test and mean values were compared between the study groups using t-test or analysis of variance (ANOVA) followed by Tukey's highly significant difference (HSD). In the present study, P age of having clinically completely erupted maxillary third molars was 22.41 years in male subjects and 23.81 years in female subjects and that of mandibular third molars was 21.49 years in male subjects and 23.34 years in female subjects. Mandibular third molars were clinically missing more often in females than in males. Eruption of mandibular third molars was generally ahead of the emergence of maxillary third molars into the oral cavity. Third molar development between male and female subjects showed statistically significant differences at calcification stage F and stage G in maxillary third molars and stage F in mandibular third molars (P third molar eruption reached Demirjian's formation stages earlier in males than in females. It is suggested that in future studies, to increase the accuracy of age determination, indications of sexual maturity and ossification should also be evaluated in addition to third molar mineralization.

Beyond chronological age: examining time and health as age-related mediators in relations to work motives

NARCIS (Netherlands)

Kooij, T.A.M.; de Lange, A.H.; Jansen, P.G.W.; Dikkers, J.S.E.

2013-01-01

Since workforces across the world are aging, researchers and organizations need more insight into how and why occupational well-being, together with work-related attitudes and motivations, change with age. Lifespan theories point to subjective health and future time perspective (i.e. an individual's

AGE DETERMINATION FROM PUBIC SYMPHYSEAL CHANGES- AN AUTOPSY STUDY

Directory of Open Access Journals (Sweden)

Jinesh Parambathettu Sasidharan

2017-02-01

Full Text Available BACKGROUND Biological identity is one of the first things to be established when analysing skeletal, badly decomposed or otherwise unidentified human remains. The determination of age at death is an important component of identity establishment. Pubic symphysis examination is one of the reliable methods of age estimation. We attempt to determine the age of deceased from pubic symphysis using Suchey-Brooks method and to find the accuracy of Suchey-Brooks method in our population. From among the cases brought for autopsy at Department of Forensic Medicine, Government Medical College, Kottayam, Kerala, from 01/03/2012 to 28/02/2013, 316 cases were included in the study. Their pubic symphysis were harvested. Age determined using SucheyBrooks method and compared with their chronological age. The aim of the study is to- 1. Determine the age of deceased from pubic symphysis using Suchey-Brooks method. 2. Compare the age determined by Suchey-Brooks method and chronological age and find the accuracy of Suchey-Brooks method in our population. MATERIALS AND METHODS Study Design- Descriptive study- Cross-sectional study, Centre of Study- Department of Forensic Medicine, Government Medical College, Kottayam, Study Sample- From the cases brought for medicolegal postmortem examination in the Department of Forensic Medicine, Government Medical College, Kottayam, Kerala, a sample of 316 cases were selected. To make the distribution among various age groups, even the total sample divided for the age group, which resulted in having 60 samples per age group. Age groups were considered as Group 1- Age between 18-25 years; Group 2- Age between 25-35 years; Group 3- Age between 35-45 years; Group 4- Age between 45-55 years; Group 5- Age between 55-65 years. Inclusion Criteria- 1. Cases with known age; 2. Cases whose age between 18 and 65 years. Exclusion Criteria- 1. Unknown cases; 2. Known cases with doubtful age; 3. Individuals having pubic bone trauma involving the

Annual age-grouping and athlete development: a meta-analytical review of relative age effects in sport.

Science.gov (United States)

Cobley, Stephen; Baker, Joseph; Wattie, Nick; McKenna, Jim

2009-01-01

Annual age-grouping is a common organizational strategy in sport. However, such a strategy appears to promote relative age effects (RAEs). RAEs refer both to the immediate participation and long-term attainment constraints in sport, occurring as a result of chronological age and associated physical (e.g. height) differences as well as selection practices in annual age-grouped cohorts. This article represents the first meta-analytical review of RAEs, aimed to collectively determine (i) the overall prevalence and strength of RAEs across and within sports, and (ii) identify moderator variables. A total of 38 studies, spanning 1984-2007, containing 253 independent samples across 14 sports and 16 countries were re-examined and included in a single analysis using odds ratios and random effects procedures for combining study estimates. Overall results identified consistent prevalence of RAEs, but with small effect sizes. Effect size increased linearly with relative age differences. Follow-up analyses identified age category, skill level and sport context as moderators of RAE magnitude. Sports context involving adolescent (aged 15-18 years) males, at the representative (i.e. regional and national) level in highly popular sports appear most at risk to RAE inequalities. Researchers need to understand the mechanisms by which RAEs magnify and subside, as well as confirm whether RAEs exist in female and more culturally diverse contexts. To reduce and eliminate this social inequality from influencing athletes' experiences, especially within developmental periods, direct policy, organizational and practitioner intervention is required.

Can aging be programmed?

DEFF Research Database (Denmark)

Kowald, Axel; Kirkwood, Thomas B. L.

2016-01-01

The evolution of the aging process has long been a biological riddle, because it is difficult to explain the evolution of a trait that has apparently no benefit to the individual. Over 60 years ago, Medawar realized that the force of natural selection declines with chronological age because...... of unavoidable environmental risks. This forms the basis of the mainstream view that aging arises as a consequence of a declining selection pressure to maintain the physiological functioning of living beings forever. Over recent years, however, a number of articles have appeared that nevertheless propose...... the existence of specific aging genes; that is, that the aging process is genetically programmed. If this view were correct, it would have serious implications for experiments to understand and postpone aging. Therefore, we studied in detail various specific proposals why aging should be programmed. We find...

Developing an assessment based on physical fitness age to evaluate motor function in frail and healthy elderly women.

Science.gov (United States)

Nakagaichi, Masaki; Anan, Yuya; Hikiji, Yuto; Uratani, Sou

2018-01-01

The purpose of this study was to identify a method for assessing physical fitness age that is easy to use with both frail and healthy elderly women and to examine its validity. Principal component analysis was used to develop a formula of physical fitness age from four motor function variables. The subjects comprised 688 (75.7±6.0 years) elderly women, in order to develop a physical fitness scale. The formula for calculating physical fitness age was expressed as physical fitness age =-0.419× grip strength -0.096× balancing on one leg with eyes open -0.737×30 s chair stand +0.503× figure-of-8 walking test +0.47× chronological age +52.68. Measures obtained from subjects in the frail elderly (n=11, 73.0±2.3 years) and exercise (n=10, 70.8±3.1 years) groups were used to examine the validity of the assessment. The mean physical fitness age of the frail elderly group (79.0±3.7 years) was significantly higher than its mean chronological age (73.0±2.3 years, p fitness age of the exercise group (65.6±3.1 years) was significantly lower than the chronological age (70.8±3.1 years, p fitness age scores are applicable to frail and healthy elderly women. Physical fitness age is a valid measure of motor function in elderly women.

Excavations and chronology at the Redcliffs Flat site, Canterbury, New Zealand

International Nuclear Information System (INIS)

Jacomb, C.

2009-01-01

The Redcliffs Flat site is one of a number of early Maori archaeological sites that cluster near the mouth of the estuary of the Avon and Heathcote rivers. Although several have been the subject of archaeological investigations, the chronology and extent of the Redcliffs Flat site remain poorly understood. Recent excavations associated with the redevelopment of a suburban section allow some progress to be made on both fronts. A small excavation here yielded a surprising amount of faunal, lithic and stratigraphic information. The site is shown to have extended to close to the edge of the estuary at the time of occupation and a radiocarbon date on a fragment of moa eggshell confirms the fourteenth to early fifteenth century status of the site. The radiocarbon chronology of the sites of the wider Redcliffs area is reviewed in light of this result. (author). 41 refs., 6 figs., 3 tabs.

Radiocarbon ages and age models for the past 30,000 years in Bear Lake, Utah and Idaho

Science.gov (United States)

Colman, Steven M.; Rosenbaum, J.G.; Kaufman, D.S.; Dean, W.E.; McGeehin, J.P.

2009-01-01

Radiocarbon analyses of pollen, ostracodes, and total organic carbon (TOC) provide a reliable chronology for the sediments deposited in Bear Lake over the past 30,000 years. The differences in apparent age between TOC, pollen, and carbonate fractions are consistent and in accord with the origins of these fractions. Comparisons among different fractions indicate that pollen sample ages are the most reliable, at least for the past 15,000 years. The post-glacial radiocarbon data also agree with ages independently estimated from aspartic acid racemization in ostracodes. Ages in the red, siliclastic unit, inferred to be of last glacial age, appear to be several thousand years too old, probably because of a high proportion of reworked, refractory organic carbon in the pollen samples. Age-depth models for five piston cores and the Bear Lake drill core (BL00-1) were constructed by using two methods: quadratic equations and smooth cubic-splinefits. The two types of age models differ only in detail for individual cores, and each approach has its own advantages. Specific lithological horizons were dated in several cores and correlated among them, producing robust average ages for these horizons. The age of the correlated horizons in the red, siliclastic unit can be estimated from the age model for BL00-1, which is controlled by ages above and below the red, siliclastic unit. These ages were then transferred to the correlative horizons in the shorter piston cores, providing control for the sections of the age models in those cores in the red, siliclastic unit. These age models are the backbone for reconstructions of past environmental conditions in Bear Lake. In general, sedimentation rates in Bear Lake have been quite uniform, mostly between 0.3 and 0.8 mm yr-1 in the Holocene, and close to 0.5 mm yr-1 for the longer sedimentary record in the drill core from the deepest part of the lake. Copyright ?? 2009 The Geological Society of America.

Blood DNA methylation age is not associated with cognitive functioning in middle-aged monozygotic twins

DEFF Research Database (Denmark)

Starnawska, A; Tan, Q; Lenart, A

2016-01-01

The epigenetic clock, also known as DNA methylation age (DNAmAge), represents age-related changes of DNA methylation at multiple sites of the genome and is suggested to be a biomarker for biological age. Elevated blood DNAmAge is associated with all-cause mortality, with the strongest effects...... reported in a recent intrapair twin study where epigenetically older twins had increased mortality risk in comparison to their co-twins. In the study presented here, we hypothesize that DNAmAge in blood is associated with cross-sectional and longitudinal cognitive abilities in middle-aged individuals....... In 486 monozygotic twins, we investigated the association of DNAmAge, difference between DNAmAge and chronological age and age acceleration with cognition. Despite using a powerful paired twin design, we found no evidence for association of blood DNAmAge with cognitive abilities. This observation...

Constraining the Source Craters of the Martian Meteorites: Implications for Prioritiziation of Returned Samples from Mars

Science.gov (United States)

Herd, C. D. K.; Tornabene, L. L.; Bowling, T. J.; Walton, E. L.; Sharp, T. G.; Melosh, H. J.; Hamilton, J. S.; Viviano, C. E.; Ehlmann, B. L.

2018-04-01

We have made advances in constraining the potential source craters of the martian meteorites to a relatively small number. Our results have implications for Mars chronology and the prioritization of samples for Mars Sample Return.

Epigenetic age analysis of children who seem to evade aging.

Science.gov (United States)

Walker, Richard F; Liu, Jia Sophie; Peters, Brock A; Ritz, Beate R; Wu, Timothy; Ophoff, Roel A; Horvath, Steve

2015-05-01

We previously reported the unusual case of a teenage girl stricken with multifocal developmental dysfunctions whose physical development was dramatically delayed resulting in her appearing to be a toddler or at best a preschooler, even unto the occasion of her death at the age of 20 years. Her life-long physician felt that the disorder was unique in the world and that future treatments for age-related diseases might emerge from its study. The objectives of our research were to determine if other such cases exist, and if so, whether aging is actually slowed. Of seven children characterized by dramatically slow developmental rates, five also had associated disorders displayed by the first case. All of the identified subjects were female. To objectively measure the age of blood tissue from these subjects, we used a highly accurate biomarker of aging known as "epigenetic clock" based on DNA methylation levels. No statistically significant differences in chronological and epigenetic ages were detected in any of the newly discovered cases.

Relationship between age and promotion orientation depends on perceived older worker stereotypes.

Science.gov (United States)

Bowen, Catherine E; Staudinger, Ursula M

2013-01-01

Research has consistently revealed a negative relationship between chronological age and promotion orientation, that is, the motivational orientation toward approaching possible gains. In addition, experimental research has demonstrated that activating positive self-relevant stereotypes (e.g., for men, the stereotype that men are good at math) can stimulate increases in promotion orientation. Integrating and applying this research to the work context, we hypothesized that the relationship between age and promotion orientation would depend on employees' perceptions of the stereotype of older workers in their work context, such that there would be no negative relationship between age and promotion orientation when individuals perceive a more positive older worker stereotype. We analyzed the relationships between age, perceived older worker stereotype (POWS), and promotion orientation using a sample of working adults (N = 337) aged 19-64 years. Results revealed a significant age by POWS interaction such that there was a negative relationship between age and promotion orientation when POWS was less positive. However, there was no relationship between age and promotion orientation when POWS was more positive. Results suggest that the negative relationship between age and promotion orientation depends on contextual factors such as POWS.

Little Ice Age Fluctuations of Quelccaya Ice Cap, Peru

Science.gov (United States)

Stroup, J. S.; Kelly, M. A.; Lowell, T.

2009-12-01

A record of the past extents of Quelccaya Ice Cap (QIC) provides valuable information about tropical climate change from late glacial to recent time. Here, we examine the timing and regional significance of fluctuations of QIC during the Little Ice Age (LIA; ~1300-1850 AD). One prominent set of moraines, known as the Huancane I moraines, is located ~1 km from the present-day western ice cap margin and provides a near-continuous outline of the most recent advance of QIC. This moraine set was radiocarbon dated (~298 ± 134 and 831 ± 87 yr BP) by Mercer and Palacios (1977) and presented as some of the first evidence for cooling in the tropics during the Little Ice Age. Recent field investigations in the QIC region focused on refining the chronology of the Huancane I moraines. In 2008, new stratigraphic sections exposed by local lake-flooding events revealed multiple layers of peat within the Huancane I moraines. In both 2008 and 2009, samples were obtained for 10Be dating of boulders on Huancane I moraines. A combination of radiocarbon and 10Be ages indicate that the Huancane I moraines were deposited by ice cap expansion after ~3800 yr BP and likely by multiple advances at approximately 1000, 600, 400, and 200 yr BP. Radiocarbon and 10Be chronologies of the Huancane I moraines are compared with the Quelccaya ice core records (Thompson et al., 1985; 1986; 2006). Accumulation data from the ice core records are interpreted to indicate a significant wet period at ~1500-1700 AD followed by a significant drought at ~1720-1860 AD. We examine ice marginal fluctuations during these times to determine influence of such events on the ice cap extent.

Chronology protection in string theory

International Nuclear Information System (INIS)

Dyson, Lisa

2004-01-01

Many solutions of General Relativity appear to allow the possibility of time travel. This was initially a fascinating discovery, but geometries of this type violate causality, a basic physical law which is believed to be fundamental. Although string theory is a proposed fundamental theory of quantum gravity, geometries with closed timelike curves have resurfaced as solutions to its low energy equations of motion. In this paper, we will study the class of solutions to low energy effective supergravity theories related to the BMPV black hole and the rotating wave-D1-D5-brane system. Time travel appears to be possible in these geometries. We will attempt to build the causality violating regions and propose that stringy effects prohibit their construction. The proposed chronology protection agent for these geometries mirrors a mechanism string theory employs to resolve a class of naked singularities. (author)

Tick-Tock Chimes the Kidney Clock – from Biology of Renal Ageing to Clinical Applications

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Joshua Rowland

2018-01-01

Full Text Available Ageing of the kidney is a multi-dimensional process that occurs simultaneously at the molecular, cellular, histological, anatomical and physiological level. Nephron number and renal cortical volume decline, renal tubules become atrophic and glomeruli become sclerotic with age. These structural changes are accompanied by a decline in glomerular filtration rate, decreased sodium reabsorption and potassium excretion, reduced urinary concentrating capacity and alterations in the endocrine activity of the kidney. However, the pace of progression of these changes is not identical in everyone - individuals of the same age and seemingly similar clinical profile often exhibit stark differences in the age-related decline in renal health. Thus, chronological age poorly reflects the time-dependent changes that occur in the kidney. An ideal measure of renal vitality is biological kidney age – a measure of the age-related changes in physiological function. Replacing chronological age with biological age could provide numerous clinical benefits including improved prognostic accuracy in renal transplantation, better stratification of risk and identification of those who are on a fast trajectory to an age-related drop in kidney health.

Into the Past: A Step Towards a Robust Kimberley Rock Art Chronology.

Science.gov (United States)

Ross, June; Westaway, Kira; Travers, Meg; Morwood, Michael J; Hayward, John

2016-01-01

The recent establishment of a minimum age estimate of 39.9 ka for the origin of rock art in Sulawesi has challenged claims that Western Europe was the locus for the production of the world's earliest art assemblages. Tantalising excavated evidence found across northern Australian suggests that Australia too contains a wealth of ancient art. However, the dating of rock art itself remains the greatest obstacle to be addressed if the significance of Australian assemblages are to be recognised on the world stage. A recent archaeological project in the northwest Kimberley trialled three dating techniques in order to establish chronological markers for the proposed, regional, relative stylistic sequence. Applications using optically-stimulated luminescence (OSL) provided nine minimum age estimates for fossilised mudwasp nests overlying a range of rock art styles, while Accelerator Mass Spectrometry radiocarbon (AMS 14C) results provided an additional four. Results confirm that at least one phase of the northwest Kimberley rock art assemblage is Pleistocene in origin. A complete motif located on the ceiling of a rockshelter returned a minimum age estimate of 16 ± 1 ka. Further, our results demonstrate the inherent problems in relying solely on stylistic classifications to order rock art assemblages into temporal sequences. An earlier than expected minimum age estimate for one style and a maximum age estimate for another together illustrate that the Holocene Kimberley rock art sequence is likely to be far more complex than generally accepted with different styles produced contemporaneously well into the last few millennia. It is evident that reliance on techniques that produce minimum age estimates means that many more dating programs will need to be undertaken before the stylistic sequence can be securely dated.

Into the Past: A Step Towards a Robust Kimberley Rock Art Chronology.

Directory of Open Access Journals (Sweden)

June Ross

Full Text Available The recent establishment of a minimum age estimate of 39.9 ka for the origin of rock art in Sulawesi has challenged claims that Western Europe was the locus for the production of the world's earliest art assemblages. Tantalising excavated evidence found across northern Australian suggests that Australia too contains a wealth of ancient art. However, the dating of rock art itself remains the greatest obstacle to be addressed if the significance of Australian assemblages are to be recognised on the world stage. A recent archaeological project in the northwest Kimberley trialled three dating techniques in order to establish chronological markers for the proposed, regional, relative stylistic sequence. Applications using optically-stimulated luminescence (OSL provided nine minimum age estimates for fossilised mudwasp nests overlying a range of rock art styles, while Accelerator Mass Spectrometry radiocarbon (AMS 14C results provided an additional four. Results confirm that at least one phase of the northwest Kimberley rock art assemblage is Pleistocene in origin. A complete motif located on the ceiling of a rockshelter returned a minimum age estimate of 16 ± 1 ka. Further, our results demonstrate the inherent problems in relying solely on stylistic classifications to order rock art assemblages into temporal sequences. An earlier than expected minimum age estimate for one style and a maximum age estimate for another together illustrate that the Holocene Kimberley rock art sequence is likely to be far more complex than generally accepted with different styles produced contemporaneously well into the last few millennia. It is evident that reliance on techniques that produce minimum age estimates means that many more dating programs will need to be undertaken before the stylistic sequence can be securely dated.

Molecular-level insights into aging processes of skin elastin.

Science.gov (United States)

Mora Huertas, Angela C; Schmelzer, Christian E H; Hoehenwarter, Wolfgang; Heyroth, Frank; Heinz, Andrea

2016-01-01

Skin aging is characterized by different features including wrinkling, atrophy of the dermis and loss of elasticity associated with damage to the extracellular matrix protein elastin. The aim of this study was to investigate the aging process of skin elastin at the molecular level by evaluating the influence of intrinsic (chronological aging) and extrinsic factors (sun exposure) on the morphology and susceptibility of elastin towards enzymatic degradation. Elastin was isolated from biopsies derived from sun-protected or sun-exposed skin of differently aged individuals. The morphology of the elastin fibers was characterized by scanning electron microscopy. Mass spectrometric analysis and label-free quantification allowed identifying differences in the cleavage patterns of the elastin samples after enzymatic digestion. Principal component analysis and hierarchical cluster analysis were used to visualize differences between the samples and to determine the contribution of extrinsic and intrinsic aging to the proteolytic susceptibility of elastin. Moreover, the release of potentially bioactive peptides was studied. Skin aging is associated with the decomposition of elastin fibers, which is more pronounced in sun-exposed tissue. Marker peptides were identified, which showed an age-related increase or decrease in their abundances and provide insights into the progression of the aging process of elastin fibers. Strong age-related cleavage occurs in hydrophobic tropoelastin domains 18, 20, 24 and 26. Photoaging makes the N-terminal and central parts of the tropoelastin molecules more susceptible towards enzymatic cleavage and, hence, accelerates the age-related degradation of elastin. Copyright © 2016 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

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

International Nuclear Information System (INIS)

Lindroos, Alf; Ranta, Heikki; 14C Dating Laboratory, Department of Physics and Astronomy, University of Aarhus (Denmark))" data-affiliation=" (AMS 14C Dating Laboratory, Department of Physics and Astronomy, University of Aarhus (Denmark))" >Heinemeier, Jan; Lill, Jan-Olof

2014-01-01

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 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 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 14 C age of the lime lumps of this particular church is an important contribution to the discussion on stone church chronology in Scandinavia

Chronology of deep nodes in the neotropical primate phylogeny: insights from mitochondrial genomes.

Science.gov (United States)

Schrago, Carlos G; Menezes, Albert N; Moreira, Miguel A M; Pissinatti, Alcides; Seuánez, Hector N

2012-01-01

The evolution of Neotropical Primates (NP) is permeated by factors associated with the pattern of diversification and the biogeography of the major lineages. These questions can be better understood by providing a robust estimate of the chronological scenario of NP evolution, a reason why molecular dating methods have been widely applied. One aspect of especial interest is the timing of diversification of the major NP lineages (pitheciids, atelids and cebids), which may have resulted from rapid episodes of adaptive radiation, a question that requires NP divergence time estimates with accurate statistical certainty. In this study, we evaluated the primate timescale focused on the age of nodes of NP radiation. We investigated the performance of complete primate mitochondrial genomes as traditional molecular markers of primate evolution and further including original mitochondrial data from the endangered muriqui, Brachyteles arachnoides (Accession No. JX262672). Comparisons of the age estimates at NP nodes based on mitochondrial genomes with those obtained from a nuclear supermatrix showed similar degrees of uncertainty. Further molecular data and more informative calibration priors are required for a more precise understanding of the early NP diversification.

Chronology of deep nodes in the neotropical primate phylogeny: insights from mitochondrial genomes.

Directory of Open Access Journals (Sweden)

Carlos G Schrago

Full Text Available The evolution of Neotropical Primates (NP is permeated by factors associated with the pattern of diversification and the biogeography of the major lineages. These questions can be better understood by providing a robust estimate of the chronological scenario of NP evolution, a reason why molecular dating methods have been widely applied. One aspect of especial interest is the timing of diversification of the major NP lineages (pitheciids, atelids and cebids, which may have resulted from rapid episodes of adaptive radiation, a question that requires NP divergence time estimates with accurate statistical certainty. In this study, we evaluated the primate timescale focused on the age of nodes of NP radiation. We investigated the performance of complete primate mitochondrial genomes as traditional molecular markers of primate evolution and further including original mitochondrial data from the endangered muriqui, Brachyteles arachnoides (Accession No. JX262672. Comparisons of the age estimates at NP nodes based on mitochondrial genomes with those obtained from a nuclear supermatrix showed similar degrees of uncertainty. Further molecular data and more informative calibration priors are required for a more precise understanding of the early NP diversification.

Differential Gene Expression and Aging

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Laurent Seroude

2002-01-01

Full Text Available It has been established that an intricate program of gene expression controls progression through the different stages in development. The equally complex biological phenomenon known as aging is genetically determined and environmentally modulated. This review focuses on the genetic component of aging, with a special emphasis on differential gene expression. At least two genetic pathways regulating organism longevity act by modifying gene expression. Many genes are also subjected to age-dependent transcriptional regulation. Some age-related gene expression changes are prevented by caloric restriction, the most robust intervention that slows down the aging process. Manipulating the expression of some age-regulated genes can extend an organism's life span. Remarkably, the activity of many transcription regulatory elements is linked to physiological age as opposed to chronological age, indicating that orderly and tightly controlled regulatory pathways are active during aging.

Preliminary U-series disequilibrium and thermoluminescence ages of surficial deposits and paleosols associated with Quaternary fault, Eastern Yucca Mountain

International Nuclear Information System (INIS)

Paces, J.B.; Menges, C.M.; Bush, C.A.; Futa, K.; Millard, H.T.; Maat, P.B.; Whitney, J.W.; Widmann, B.; Wesling, J.R.

1994-01-01

Geochronological control is an essential component of paleoseismic evaluation of faults in the Yucca Mountain region. New U-series disequilibrium and thermoluminescence age estimates for pedogenic deposits that bracket surface-rupture events are presented from four sites exposing the Paintbrush Canyon, Bow Ridge and Stagecoach Road faults. Ages show an internal consistency with stratigraphic relationships as well as an overall concordancy between the two independent geochronometers. Age estimates are therefore interpreted to date depositional events or episodes of pedogenic carbonate mobility that can be used to establish a paleoseismic fault chronology. Ultimately, this type of chronological information will be used to evaluate seismic hazards at Yucca Mountain

Are Psychosocial Resources Associated With Perceived Facial Aging in Men?

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Emilou Noser MSc

2017-06-01

Full Text Available Background: Looking younger than actual age has been related to a variety of health outcomes. Optimism, self-esteem, and relationship satisfaction are important psychosocial resources for mental health. Little is known about their relation with a younger facial appearance. Objective: This study analyzed whether these psychosocial resources are associated with a younger facial appearance and if their effects were mediated through mental health. Method: A sample of N = 223 self-reporting healthy men aged 40 to 75 years filled in questionnaires to assess optimism (Life Orientation Test–Revised, self-esteem (Multidimensional Self-Esteem Scale, relationship satisfaction (Relationship Assessment Scale, and mental health (Short-Form Health Survey. Five female raters estimated the visual age of each participant from a frontal face photograph. Results: Looking younger (compared with chronological age was correlated with optimism, relationship satisfaction, and mental health. Mediation analyses and structural equation modeling indicated that mental health mediated the association between each psychosocial resource and a younger appearance. Discussion: The results emphasize the importance of promoting psychosocial resources and mental health in men 40+ for the maintenance of good health and the deceleration of facial aging.

Motor Deficits of Girls with Down Syndrome in Comparing with Girls with Intellectual Disability in the School Ages Children

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Tahereh Daftari-Anbardan

2014-03-01

Full Text Available Objective: Motor function in children with Down syndrome is similar to mentally retarded children. But the movements are slower and have lower quality. The purpose of this study was to identify weaknesses in motor function in children with Down syndrome, by using Bruininks Oseretsky Test of Motor Proficiency (BOTMP. Materials & Methods: In this cross-sectional study, thirty six children with intellectual disability, 18 girls with Down syndrome and 18 girls without Down syndrome, with chronological aged 8-13 years were investigated. The subjects of Down syndrome were selected by available sampling. The subjects of intellectual disability were selected by simple random sampling. Two groups of participants were matched for chronological age and IQ level. The measurement was BOTMP. Statistical analysis was performed using the Mann-Whitney U rank sum test and t-test. Results: The children with Down syndrome scored significantly lower than the mentally retarded children in the areas of gross motor skill composite (P<0.014 balance (P<0.029, response time (P<0.034 and visual motor control (P<0.048, but the fine motor and overlay motor skill composite, and subtests of bilateral coordination, strength, upper limb coordination scores were no significantly different between two groups. Conclusion: Motor rehabilitation is appropriate for children with intellectual disability, especially for children with Down syndrome, in throughout their adolescence. Key words: Motor skill/ Intellectual Disability/ Down syndrome/ BOTMP

Chronology and palaeoenvironmental implications of the ice-wedge pseudomorphs and composite-wedge casts on the Magdalen Islands (eastern Canada)

DEFF Research Database (Denmark)

Remillard, A.M.; Hetu, B.; Bernatchez, P.

2015-01-01

to the former presence of permafrost under periglacial conditions. These features truncate Carboniferous sandstone or Last Glacial Maximum (LGM) glacial and glaciomarine diamicts, both overlain by subtidal or coastal units. Six optically stimulated luminescence (OSL) and four radiocarbon ages were obtained from......The Magdalen Islands are a valuable terrestrial record, evidencing the complex glacial and periglacial history of the Gulf of St. Lawrence. Thirteen structures interpreted as ice-wedge pseudomorphs or composite-wedge casts were observed at four sites on the southern Magdalen Islands and testify...... both host and infilled sedimentary units. These ages provide the first absolute chronological data on these structures, shedding new light on the relationships between glacial and periglacial phases. Our chronostratigraphic data suggest that, after the deglaciation and the emersion of the archipelago...

Predicting brain age with deep learning from raw imaging data results in a reliable and heritable biomarker

NARCIS (Netherlands)

Cole, James H.; Poudel, Rudra P. K.; Tsagkrasoulis, Dimosthenis; Caan, Matthan W. A.; Steves, Claire; Spector, Tim D.; Montana, Giovanni

2017-01-01

Machine learning analysis of neuroimaging data can accurately predict chronological age in healthy people. Deviations from healthy brain ageing have been associated with cognitive impairment and disease. Here we sought to further establish the credentials of 'brain-predicted age' as a biomarker of

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

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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

[Establish Assessment Model of 18 Years of Age in Chinese Han Population by Mandibular Third Molar].

Science.gov (United States)

Fan, Fei; Dai, Xin-hua; Wang, Liang; Li, Yuan; Zhang, Kui; Deng, Zhen-hua

2016-02-01