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Sample records for age estimates derived

  1. Direct Density Derivative Estimation.

    PubMed

    Sasaki, Hiroaki; Noh, Yung-Kyun; Niu, Gang; Sugiyama, Masashi

    2016-06-01

    Estimating the derivatives of probability density functions is an essential step in statistical data analysis. A naive approach to estimate the derivatives is to first perform density estimation and then compute its derivatives. However, this approach can be unreliable because a good density estimator does not necessarily mean a good density derivative estimator. To cope with this problem, in this letter, we propose a novel method that directly estimates density derivatives without going through density estimation. The proposed method provides computationally efficient estimation for the derivatives of any order on multidimensional data with a hyperparameter tuning method and achieves the optimal parametric convergence rate. We further discuss an extension of the proposed method by applying regularized multitask learning and a general framework for density derivative estimation based on Bregman divergences. Applications of the proposed method to nonparametric Kullback-Leibler divergence approximation and bandwidth matrix selection in kernel density estimation are also explored. PMID:27140943

  2. Age-specific survival estimates of King Eiders derived from satellite telemetry

    USGS Publications Warehouse

    Oppel, Steffen; Powell, Abby N.

    2010-01-01

    Age- and sex-specific survival and dispersal are important components in the dynamics and genetic structure of bird populations. For many avian taxa survival rates at the adult and juvenile life stages differ, but in long-lived species juveniles' survival is logistically challenging to study. We present the first estimates of hatch-year annual survival rates for a sea duck, the King Eider (Somateria spectabilis), estimated from satellite telemetry. From 2006 to 2008 we equipped pre-fiedging King Eiders with satellite transmitters on breeding grounds in Alaska and estimated annual survival rates during their first 2 years of life with known-fate models. We compared those estimates to survival rates of adults marked in the same area from 2002 to 2008. Hatch-year survival varied by season during the first year of life, and model-averaged annual survival rate was 0.67 (95% CI: 0.48–0.80). We did not record any mortality during the second year and were therefore unable to estimate second-year survival rate. Adults' survival rate was constant through the year (0.94, 95% CI: 0.86–0.97). No birds appeared to breed during their second summer. While 88% of females with an active transmitter (n = 9) returned to their natal area at the age of 2 years, none of the 2-year old males (n = 3) did. This pattern indicates that females' natal philopatry is high and suggests that males' higher rates of dispersal may account for sex-specific differences in apparent survival rates of juvenile sea ducks when estimated with mark—recapture methods.

  3. Model-derived estimates of groundwater mean ages, recharge rates, effective porosities and storage in a limestone aquifer

    NASA Astrophysics Data System (ADS)

    Campana, M. E.; Mahin, D. A.

    1985-02-01

    The Edwards aquifer of south-central Texas, U.S.A., a highly fractured and faulted group of limestone formations, is the major water supply for the San Antonio area. A discrete-state compartment (DSC) model or mixing-cell model, based upon the conservation of environmental tritium within the aquifer, was used to obtain estimates of groundwater mean ages, recharge, effective porosities and storage in the Edwards aquifer in the vicinity of San Antonio, Texas. The model was calibrated and validated with the spatial and temporal (1953-1971) distributions of environmental 3H (tritium) in the groundwater. The final model consisted of 34 cells; eight of these cells represented the unconfined portion of the Edwards aquifer in the vicinity of the Balcones fault zone, an area where recharge occurs via streamflow infiltration and direct infiltration of precipitation. The model confirmed previous analyses of flow in the Edwards system: generally parallel to the Balcones fault zone with restricted flow perpendicular to this zone. Groundwater mean ages ranged from 16 to over 130 yr. The storage volume of the confined portion of the Edwards aquifer is ˜ 30.9 km 3, which corresponds to an average effective porosity of 4.8% (range: 1.9-8%). The average annual recharge to the Edwards aquifer during the period 1953-1971 was 0.614 km 3. The study demonstrated that discrete-state compartment models calibrated and validated with environmental tritium distributions can yield valuable hydrogeologic information that is difficult or expensive to obtain using traditional techniques. The approach used in the study is particularly suited to limestone aquifers, which are normally extremely difficult to analyze with traditional methods.

  4. Age estimation from canine volumes.

    PubMed

    De Angelis, Danilo; Gaudio, Daniel; Guercini, Nicola; Cipriani, Filippo; Gibelli, Daniele; Caputi, Sergio; Cattaneo, Cristina

    2015-08-01

    Techniques for estimation of biological age are constantly evolving and are finding daily application in the forensic radiology field in cases concerning the estimation of the chronological age of a corpse in order to reconstruct the biological profile, or of a living subject, for example in cases of immigration of people without identity papers from a civil registry. The deposition of teeth secondary dentine and consequent decrease of pulp chamber in size are well known as aging phenomena, and they have been applied to the forensic context by the development of age estimation procedures, such as Kvaal-Solheim and Cameriere methods. The present study takes into consideration canines pulp chamber volume related to the entire teeth volume, with the aim of proposing new regression formulae for age estimation using 91 cone beam computerized scans and a freeware open-source software, in order to permit affordable reproducibility of volumes calculation.

  5. Position Estimation Using Image Derivative

    NASA Technical Reports Server (NTRS)

    Mortari, Daniele; deDilectis, Francesco; Zanetti, Renato

    2015-01-01

    This paper describes an image processing algorithm to process Moon and/or Earth images. The theory presented is based on the fact that Moon hard edge points are characterized by the highest values of the image derivative. Outliers are eliminated by two sequential filters. Moon center and radius are then estimated by nonlinear least-squares using circular sigmoid functions. The proposed image processing has been applied and validated using real and synthetic Moon images.

  6. Age estimation in subadult Egyptian remains.

    PubMed

    Boccone, S; Micheletti Cremasco, M; Bortoluzzi, S; Moggi-Cecchi, J; Rabino Massa, E

    2010-10-01

    In anthropological analyses of past populations, it is very important to be able to accurately reconstruct the palaeodemographic profile in order to interpret infant mortality as an indicator of the environmental, social and cultural conditions. There are various methods to evaluate the age of immature individuals but some of these methods are strongly influenced by the different rates of skeletal development observed in populations from various geographical areas and/or from various time periods, as well as between the sexes. Clearly, there is a need for adopting a method of estimation of age at death, which will be the one most suitable for analysing the particular skeletal sample. In this study we investigated subadults from the Egyptian osteological collection housed in the Museum of Anthropology and Ethnography of the University of Turin. For each individual, the age at death was estimated based on the degree of eruption and mineralisation of the teeth. Then the estimated age at death was correlated with the measurements of the long bones and ilium. We showed that greater regularity and constancy of rates of skeletal growth could be assessed with measurements, alternative to using maximum length of diaphysis. Moreover, using alternative characters, it was possible to markedly increase the number of individuals whose age at death could be estimated. Our study also showed the need to use a reference sample consistent with the sample being analysed and, which was derived from similar biological-environmental context. Therefore, our proposed method can be used for the estimation of age at death in pre/protohistorical populations from the Mediterranean region.

  7. Ages estimated from a diffusion equation model for scarp degradation

    USGS Publications Warehouse

    Colman, Steven M.; Watson, K.E.N.

    1983-01-01

    The diffusion equation derived from the continuity equation for hillslopes is applied to scarp erosion in unconsolidated materials. Solutions to this equation allow direct calculation of the product of the rate coefficient and the age of the scarp from measurements of scarp morphology. Where the rate coefficient can be estimated or can be derived from scarps of known age, this method allows direct calculation of unknown ages of scarps.

  8. Ethics in age estimation of unaccompanied minors.

    PubMed

    Thevissen, P W; Kvaal, S I; Willems, G

    2012-11-30

    Children absconding from countries of conflict and war are often not able to document their age. When an age is given, it is frequently untraceable or poorly documented and therefore questioned by immigration authorities. Consequently many countries perform age estimations on these children. Provision of ethical practice during the age estimation investigation of unaccompanied minors is considered from different angles: (1) The UN convention on children's rights, formulating specific rights, protection, support, healthcare and education for unaccompanied minors. (2) Since most age estimation investigations are based on medical examination, the four basic principles of biomedical ethics, namely autonomy, beneficence, non-malevolence, justice. (3) The use of medicine for non treatment purposes. (4) How age estimates with highest accuracy in age prediction can be obtained. Ethical practice in age estimation of unaccompanied minors is achieved when different but related aspects are searched, evaluated, weighted in importance and subsequently combined. However this is not always feasible and unanswered questions remain.

  9. Comparing different classifiers for automatic age estimation.

    PubMed

    Lanitis, Andreas; Draganova, Chrisina; Christodoulou, Chris

    2004-02-01

    We describe a quantitative evaluation of the performance of different classifiers in the task of automatic age estimation. In this context, we generate a statistical model of facial appearance, which is subsequently used as the basis for obtaining a compact parametric description of face images. The aim of our work is to design classifiers that accept the model-based representation of unseen images and produce an estimate of the age of the person in the corresponding face image. For this application, we have tested different classifiers: a classifier based on the use of quadratic functions for modeling the relationship between face model parameters and age, a shortest distance classifier, and artificial neural network based classifiers. We also describe variations to the basic method where we use age-specific and/or appearance specific age estimation methods. In this context, we use age estimation classifiers for each age group and/or classifiers for different clusters of subjects within our training set. In those cases, part of the classification procedure is devoted to choosing the most appropriate classifier for the subject/age range in question, so that more accurate age estimates can be obtained. We also present comparative results concerning the performance of humans and computers in the task of age estimation. Our results indicate that machines can estimate the age of a person almost as reliably as humans.

  10. Bayesian estimation of isotopic age differences

    SciTech Connect

    Curl, R.L.

    1988-08-01

    Isotopic dating is subject to uncertainties arising from counting statistics and experimental errors. These uncertainties are additive when an isotopic age difference is calculated. If large, they can lead to no significant age difference by classical statistics. In many cases, relative ages are known because of stratigraphic order or other clues. Such information can be used to establish a Bayes estimate of age difference which will include prior knowledge of age order. Age measurement errors are assumed to be log-normal and a noninformative but constrained bivariate prior for two true ages in known order is adopted. True-age ratio is distributed as a truncated log-normal variate. Its expected value gives an age-ratio estimate, and its variance provides credible intervals. Bayesian estimates of ages are different and in correct order even if measured ages are identical or reversed in order. For example, age measurements on two samples might both yield 100 ka with coefficients of variation of 0.2. Bayesian estimates are 22.7 ka for age difference with a 75% credible interval of (4.4, 43.7) ka.

  11. Age estimation based on Kvaal's technique using digital panoramic radiographs

    PubMed Central

    Mittal, Samta; Nagendrareddy, Suma Gundareddy; Sharma, Manisha Lakhanpal; Agnihotri, Poornapragna; Chaudhary, Sunil; Dhillon, Manu

    2016-01-01

    Introduction: Age estimation is important for administrative and ethical reasons and also because of legal consequences. Dental pulp undergoes regression in size with increasing age due to secondary dentin deposition and can be used as a parameter of age estimation even beyond 25 years of age. Kvaal et al. developed a method for chronological age estimation based on the pulp size using periapical dental radiographs. There is a need for testing this method of age estimation in the Indian population using simple tools like digital imaging on living individuals not requiring extraction of teeth. Aims and Objectives: Estimation of the chronological age of subjects by Kvaal's method using digital panoramic radiographs and also testing the validity of regression equations as given by Kvaal et al. Materials and Methods: The study sample included a total of 152 subjects in the age group of 14-60 years. Measurements were performed on the standardized digital panoramic radiographs based on Kvaal's method. Different regression formulae were derived and the age was assessed. The assessed age was then correlated to the actual age of the patient using Student's t-test. Results: No significant difference between the mean of the chronological age and the estimated age was observed. However, the values of the mean age estimated by using regression equations as given previously in the study of Kvaal et al. significantly underestimated the chronological age in the present study sample. Conclusion: The results of the study give an inference for the feasibility of this technique by calculation of regression equations on digital panoramic radiographs. However, it negates the applicability of same regression equations as given by Kvaal et al. on the study population. PMID:27555738

  12. [Using Lamendin and Meindl-Lovejoy methods for age at death estimation of the unknown person].

    PubMed

    Bednarek, Jarosław; Engelgardt, Piotr; Bloch-Bogusławska, Elzbieta; Sliwka, Karol

    2002-01-01

    The paper presents the precise description of two methods used for age estimation on the base of single rooted tooth and cranial suture obliteration. Using the methods mentioned above, the age at death of the unknown person was estimated. A comparison of the estimated age and chronological age derived after identification, showed high usefulness of the mentioned methods.

  13. Bayesian calibration for forensic age estimation.

    PubMed

    Ferrante, Luigi; Skrami, Edlira; Gesuita, Rosaria; Cameriere, Roberto

    2015-05-10

    Forensic medicine is increasingly called upon to assess the age of individuals. Forensic age estimation is mostly required in relation to illegal immigration and identification of bodies or skeletal remains. A variety of age estimation methods are based on dental samples and use of regression models, where the age of an individual is predicted by morphological tooth changes that take place over time. From the medico-legal point of view, regression models, with age as the dependent random variable entail that age tends to be overestimated in the young and underestimated in the old. To overcome this bias, we describe a new full Bayesian calibration method (asymmetric Laplace Bayesian calibration) for forensic age estimation that uses asymmetric Laplace distribution as the probability model. The method was compared with three existing approaches (two Bayesian and a classical method) using simulated data. Although its accuracy was comparable with that of the other methods, the asymmetric Laplace Bayesian calibration appears to be significantly more reliable and robust in case of misspecification of the probability model. The proposed method was also applied to a real dataset of values of the pulp chamber of the right lower premolar measured on x-ray scans of individuals of known age.

  14. Calibrating recruitment estimates for mourning doves from harvest age ratios

    USGS Publications Warehouse

    Miller, David A.; Otis, David L.

    2010-01-01

    We examined results from the first national-scale effort to estimate mourning dove (Zenaida macroura) age ratios and developed a simple, efficient, and generalizable methodology for calibrating estimates. Our method predicted age classes of unknown-age wings based on backward projection of molt distributions from fall harvest collections to preseason banding. We estimated 1) the proportion of late-molt individuals in each age class, and 2) the molt rates of juvenile and adult birds. Monte Carlo simulations demonstrated our estimator was minimally biased. We estimated model parameters using 96,811 wings collected from hunters and 42,189 birds banded during preseason from 68 collection blocks in 22 states during the 2005–2007 hunting seasons. We also used estimates to derive a correction factor, based on latitude and longitude of samples, which can be applied to future surveys. We estimated differential vulnerability of age classes to harvest using data from banded birds and applied that to harvest age ratios to estimate population age ratios. Average, uncorrected age ratio of known-age wings for states that allow hunting was 2.25 (SD 0.85) juveniles:adult, and average, corrected ratio was 1.91 (SD 0.68), as determined from harvest age ratios from an independent sample of 41,084 wings collected from random hunters in 2007 and 2008. We used an independent estimate of differential vulnerability to adjust corrected harvest age ratios and estimated the average population age ratio as 1.45 (SD 0.52), a direct measure of recruitment rates. Average annual recruitment rates were highest east of the Mississippi River and in the northwestern United States, with lower rates between. Our results demonstrate a robust methodology for calibrating recruitment estimates for mourning doves and represent the first large-scale estimates of recruitment for the species. Our methods can be used by managers to correct future harvest survey data to generate recruitment estimates for use in

  15. Age estimation of indian adults from orthopantomographs.

    PubMed

    Saxena, Sudhanshu

    2011-01-01

    The aim of this study was to develop a method for estimating the chronological age of Indian adults based on the relationship between age and various morphological variables of canine teeth, obtained using orthopantomographs. Orthopantomographs of 120 selected patients were digitized, and radiographic images of the right maxillary canine in each case were processed using a computer aided drafting program. Pulp/tooth area ratio, pulp/root length ratio, pulp/tooth length ratio, pulp/root width ratio at the cemento-enamel junction level, pulp/root width ratio at midroot level, and pulp/root width ratio at the midpoint between the cemento-enamel junction and the midroot of the canine were calculated by measuring various features on the images. Pearson's correlation, multiple linear regression, one way analysis of variance (ANOVA), and Student's t-test were used for statistical analysis. Regression equations were developed to estimate age from morphological variables. The observed minus the estimated age in the total study sample ranged from -2.2 to +1.5 years, in males from -0.9 to +0.8 years, while in females it was from -1 to +0.8 years. Differences between observed and estimated ages of subjects were not statistically significant. In conclusion there is a linear relationship of pulp/root width ratio at mid-root level and pulp/tooth area ratio of the right maxillary canine with chronological age in the Indian population. Age of subjects can therefore be estimated with a good degree of accuracy using regression equations. PMID:21503416

  16. Age synthesis and estimation via faces: a survey.

    PubMed

    Fu, Yun; Guo, Guodong; Huang, Thomas S

    2010-11-01

    Human age, as an important personal trait, can be directly inferred by distinct patterns emerging from the facial appearance. Derived from rapid advances in computer graphics and machine vision, computer-based age synthesis and estimation via faces have become particularly prevalent topics recently because of their explosively emerging real-world applications, such as forensic art, electronic customer relationship management, security control and surveillance monitoring, biometrics, entertainment, and cosmetology. Age synthesis is defined to rerender a face image aesthetically with natural aging and rejuvenating effects on the individual face. Age estimation is defined to label a face image automatically with the exact age (year) or the age group (year range) of the individual face. Because of their particularity and complexity, both problems are attractive yet challenging to computer-based application system designers. Large efforts from both academia and industry have been devoted in the last a few decades. In this paper, we survey the complete state-of-the-art techniques in the face image-based age synthesis and estimation topics. Existing models, popular algorithms, system performances, technical difficulties, popular face aging databases, evaluation protocols, and promising future directions are also provided with systematic discussions.

  17. Age synthesis and estimation via faces: a survey.

    PubMed

    Fu, Yun; Guo, Guodong; Huang, Thomas S

    2010-11-01

    Human age, as an important personal trait, can be directly inferred by distinct patterns emerging from the facial appearance. Derived from rapid advances in computer graphics and machine vision, computer-based age synthesis and estimation via faces have become particularly prevalent topics recently because of their explosively emerging real-world applications, such as forensic art, electronic customer relationship management, security control and surveillance monitoring, biometrics, entertainment, and cosmetology. Age synthesis is defined to rerender a face image aesthetically with natural aging and rejuvenating effects on the individual face. Age estimation is defined to label a face image automatically with the exact age (year) or the age group (year range) of the individual face. Because of their particularity and complexity, both problems are attractive yet challenging to computer-based application system designers. Large efforts from both academia and industry have been devoted in the last a few decades. In this paper, we survey the complete state-of-the-art techniques in the face image-based age synthesis and estimation topics. Existing models, popular algorithms, system performances, technical difficulties, popular face aging databases, evaluation protocols, and promising future directions are also provided with systematic discussions. PMID:20847387

  18. Mean Density Estimation derived from Satellite Constellations

    NASA Astrophysics Data System (ADS)

    Li, A.; Close, S.

    2015-12-01

    With the advent of nanosatellite constellations, we define here a new method to derive neutral densities of the lower thermosphere from multiple similar platforms travelling through same regions of space. Because of similar orbits, the satellites are expected to encounter similar mean neutral densities and hence experience similar drag if their drag coefficients are equivalent. Utilizing free molecular flow theory to bound the minimum possible drag coefficient possible and order statistics to give a statistical picture of the distribution, we are able to estimate the neutral density alongside its associated error bounds. Data sources for this methodology can either be from already established Two Line Elements (TLEs) or from raw data sources, in which an additional filtering step needs to be performed to estimate relevant parameters. The effects of error in the filtering step of the methodology are also discussed and can be removed if the error distribution is Gaussian in nature. This method does not depend on prior models of the atmosphere, but instead is based upon physics models of simple shapes in free molecular flow. With a constellation of 10 satellites, we can achieve a standard deviation of roughly 4% on the estimated mean neutral density. As additional satellites are included in the estimation scheme, the result converges towards the lower limit of the achievable drag coefficient, and accuracy becomes limited by the quality of the ranging measurements and the probability of the accommodation coefficient. Data is provided courtesy of Planet Labs and comparisons are made to existing atmospheric models such as NRLMSISE-00 and JB2006.

  19. Bayesian phylogenetic estimation of fossil ages

    PubMed Central

    Drummond, Alexei J.; Stadler, Tanja

    2016-01-01

    Recent advances have allowed for both morphological fossil evidence and molecular sequences to be integrated into a single combined inference of divergence dates under the rule of Bayesian probability. In particular, the fossilized birth–death tree prior and the Lewis-Mk model of discrete morphological evolution allow for the estimation of both divergence times and phylogenetic relationships between fossil and extant taxa. We exploit this statistical framework to investigate the internal consistency of these models by producing phylogenetic estimates of the age of each fossil in turn, within two rich and well-characterized datasets of fossil and extant species (penguins and canids). We find that the estimation accuracy of fossil ages is generally high with credible intervals seldom excluding the true age and median relative error in the two datasets of 5.7% and 13.2%, respectively. The median relative standard error (RSD) was 9.2% and 7.2%, respectively, suggesting good precision, although with some outliers. In fact, in the two datasets we analyse, the phylogenetic estimate of fossil age is on average less than 2 Myr from the mid-point age of the geological strata from which it was excavated. The high level of internal consistency found in our analyses suggests that the Bayesian statistical model employed is an adequate fit for both the geological and morphological data, and provides evidence from real data that the framework used can accurately model the evolution of discrete morphological traits coded from fossil and extant taxa. We anticipate that this approach will have diverse applications beyond divergence time dating, including dating fossils that are temporally unconstrained, testing of the ‘morphological clock', and for uncovering potential model misspecification and/or data errors when controversial phylogenetic hypotheses are obtained based on combined divergence dating analyses. This article is part of the themed issue ‘Dating species divergences

  20. Bayesian phylogenetic estimation of fossil ages.

    PubMed

    Drummond, Alexei J; Stadler, Tanja

    2016-07-19

    Recent advances have allowed for both morphological fossil evidence and molecular sequences to be integrated into a single combined inference of divergence dates under the rule of Bayesian probability. In particular, the fossilized birth-death tree prior and the Lewis-Mk model of discrete morphological evolution allow for the estimation of both divergence times and phylogenetic relationships between fossil and extant taxa. We exploit this statistical framework to investigate the internal consistency of these models by producing phylogenetic estimates of the age of each fossil in turn, within two rich and well-characterized datasets of fossil and extant species (penguins and canids). We find that the estimation accuracy of fossil ages is generally high with credible intervals seldom excluding the true age and median relative error in the two datasets of 5.7% and 13.2%, respectively. The median relative standard error (RSD) was 9.2% and 7.2%, respectively, suggesting good precision, although with some outliers. In fact, in the two datasets we analyse, the phylogenetic estimate of fossil age is on average less than 2 Myr from the mid-point age of the geological strata from which it was excavated. The high level of internal consistency found in our analyses suggests that the Bayesian statistical model employed is an adequate fit for both the geological and morphological data, and provides evidence from real data that the framework used can accurately model the evolution of discrete morphological traits coded from fossil and extant taxa. We anticipate that this approach will have diverse applications beyond divergence time dating, including dating fossils that are temporally unconstrained, testing of the 'morphological clock', and for uncovering potential model misspecification and/or data errors when controversial phylogenetic hypotheses are obtained based on combined divergence dating analyses.This article is part of the themed issue 'Dating species divergences using

  1. Bayesian phylogenetic estimation of fossil ages.

    PubMed

    Drummond, Alexei J; Stadler, Tanja

    2016-07-19

    Recent advances have allowed for both morphological fossil evidence and molecular sequences to be integrated into a single combined inference of divergence dates under the rule of Bayesian probability. In particular, the fossilized birth-death tree prior and the Lewis-Mk model of discrete morphological evolution allow for the estimation of both divergence times and phylogenetic relationships between fossil and extant taxa. We exploit this statistical framework to investigate the internal consistency of these models by producing phylogenetic estimates of the age of each fossil in turn, within two rich and well-characterized datasets of fossil and extant species (penguins and canids). We find that the estimation accuracy of fossil ages is generally high with credible intervals seldom excluding the true age and median relative error in the two datasets of 5.7% and 13.2%, respectively. The median relative standard error (RSD) was 9.2% and 7.2%, respectively, suggesting good precision, although with some outliers. In fact, in the two datasets we analyse, the phylogenetic estimate of fossil age is on average less than 2 Myr from the mid-point age of the geological strata from which it was excavated. The high level of internal consistency found in our analyses suggests that the Bayesian statistical model employed is an adequate fit for both the geological and morphological data, and provides evidence from real data that the framework used can accurately model the evolution of discrete morphological traits coded from fossil and extant taxa. We anticipate that this approach will have diverse applications beyond divergence time dating, including dating fossils that are temporally unconstrained, testing of the 'morphological clock', and for uncovering potential model misspecification and/or data errors when controversial phylogenetic hypotheses are obtained based on combined divergence dating analyses.This article is part of the themed issue 'Dating species divergences using

  2. Using Dental Age to Estimate Chronological Age in Czech Children Aged 3-18 Years.

    PubMed

    Ginzelová, Kristina; Dostálová, Taťjana; Eliášová, Hana; Vinšů, Alex; Buček, Antonín; Bučková, Michaela

    2015-01-01

    The Demirjian methods to determine dental age are based on analysis of orthopantograms. The dental age estimation is based on establishing the tooth development stages. The purpose of this study was to assess the accuracy of estimation of dental age by Demirjian in the use of all of his four methods. 505 Czech healthy boys and girls aged 3 to 18 years were examined radiographically at the Department of Stomatology, Second Faculty of Medicine, Charles University in Prague. It was mentioned the factors of underlying diseases influence the accuracy of the dental age estimation. For statistical evaluation, descriptive statistics was used to compare deviations of the mean values of chronological and dental age in each age group. The resulting difference between dental age and chronological age is not significant in both genders only when using both Demirjian 7-teeth methods of 1973 and 1976. Therefore these may be most appropriately used for forensic age estimation. There are shown standard deviation differences in different countries. Demirjian's original 7-teeth method from 1973 and Demirjian's revised 4-teeth method from 1976 appear to be the best methods for calculating the dental age of healthy Czech children of both genders. PMID:26093668

  3. Digital approach for measuring dentin translucency in forensic age estimation

    PubMed Central

    Singh, Simranjit; Venkatapathy, Ramesh; Balamurali, PD; Charles, NSC; Suganya, R

    2013-01-01

    Background: Dentin translucency is best suited for age estimation not only in terms of accuracy but also in terms of simplicity. Conventionally, translucency has been measured using calipers. Computer-based methods have been proposed for the same, although these required the use of custom-built software programs. Objectives: The objectives of the study were to use a simple digital method to measure dentinal translucency on sectioned teeth and to compare digital measurements to conventionally obtained translucency measurements. Materials and Methods: Fifty extracted permanent teeth were collected and were sectioned to 250 μm. Translucency measurements were obtained using the digital method and compared with those obtained using a caliper. Results: Correlation coefficients of translucency measurements to age were statistically significant for both methods (P < 0.001), and marginally higher for the conventional approach (r = 0.4671). Application of derived linear regression equations on an independent sample (n = 10) revealed a similar ability of both the methods to assess age to within ±5 years of the actual age. Conclusion: The translucency measurements obtained by the two methods were very similar, with no clear superiority of one method over the other. Hence, further studies on a large scale are warranted to determine which method is more reliable to estimate the age. PMID:23960415

  4. Age Estimation of African Lions Panthera leo by Ratio of Tooth Areas.

    PubMed

    White, Paula A; Ikanda, Dennis; Ferrante, Luigi; Chardonnet, Philippe; Mesochina, Pascal; Cameriere, Roberto

    2016-01-01

    Improved age estimation of African lions Panthera leo is needed to address a number of pressing conservation issues. Here we present a formula for estimating lion age to within six months of known age based on measuring the extent of pulp closure from X-rays, or Ratio Of tooth AReas (ROAR). Derived from measurements taken from lions aged 3-13 years for which exact ages were known, the formula explains 92% of the total variance. The method of calculating the pulp/tooth area ratio, which has been used extensively in forensic science, is novel in the study of lion aging. As a quantifiable measure, ROAR offers improved lion age estimates for population modeling and investigations of age-related mortality, and may assist national and international wildlife authorities in judging compliance with regulatory measures involving age.

  5. Age Estimation of African Lions Panthera leo by Ratio of Tooth Areas.

    PubMed

    White, Paula A; Ikanda, Dennis; Ferrante, Luigi; Chardonnet, Philippe; Mesochina, Pascal; Cameriere, Roberto

    2016-01-01

    Improved age estimation of African lions Panthera leo is needed to address a number of pressing conservation issues. Here we present a formula for estimating lion age to within six months of known age based on measuring the extent of pulp closure from X-rays, or Ratio Of tooth AReas (ROAR). Derived from measurements taken from lions aged 3-13 years for which exact ages were known, the formula explains 92% of the total variance. The method of calculating the pulp/tooth area ratio, which has been used extensively in forensic science, is novel in the study of lion aging. As a quantifiable measure, ROAR offers improved lion age estimates for population modeling and investigations of age-related mortality, and may assist national and international wildlife authorities in judging compliance with regulatory measures involving age. PMID:27089506

  6. Age Estimation of African Lions Panthera leo by Ratio of Tooth Areas

    PubMed Central

    Ikanda, Dennis; Ferrante, Luigi; Chardonnet, Philippe; Mesochina, Pascal; Cameriere, Roberto

    2016-01-01

    Improved age estimation of African lions Panthera leo is needed to address a number of pressing conservation issues. Here we present a formula for estimating lion age to within six months of known age based on measuring the extent of pulp closure from X-rays, or Ratio Of tooth AReas (ROAR). Derived from measurements taken from lions aged 3–13 years for which exact ages were known, the formula explains 92% of the total variance. The method of calculating the pulp/tooth area ratio, which has been used extensively in forensic science, is novel in the study of lion aging. As a quantifiable measure, ROAR offers improved lion age estimates for population modeling and investigations of age-related mortality, and may assist national and international wildlife authorities in judging compliance with regulatory measures involving age. PMID:27089506

  7. Estimating Neuronal Ageing with Hidden Markov Models

    NASA Astrophysics Data System (ADS)

    Wang, Bing; Pham, Tuan D.

    2011-06-01

    Neuronal degeneration is widely observed in normal ageing, meanwhile the neurode-generative disease like Alzheimer's disease effects neuronal degeneration in a faster way which is considered as faster ageing. Early intervention of such disease could benefit subjects with potentials of positive clinical outcome, therefore, early detection of disease related brain structural alteration is required. In this paper, we propose a computational approach for modelling the MRI-based structure alteration with ageing using hidden Markov model. The proposed hidden Markov model based brain structural model encodes intracortical tissue/fluid distribution using discrete wavelet transformation and vector quantization. Further, it captures gray matter volume loss, which is capable of reflecting subtle intracortical changes with ageing. Experiments were carried out on healthy subjects to validate its accuracy and robustness. Results have shown its ability of predicting the brain age with prediction error of 1.98 years without training data, which shows better result than other age predition methods.

  8. Impairment of age estimation from faces in Alzheimer's disease.

    PubMed

    Moyse, Evelyne; Bastin, Christine; Salmon, Eric; Brédart, Serge

    2015-01-01

    A prerequisite for any function in social cognition is the perception and processing of social cues. Age estimation is a skill that is used in everyday life and is fundamental in social interactions. This study evaluated whether facial age estimation is impaired in patients with mild to moderate Alzheimer's disease (AD). The current age of faces is known to have an impact on age estimation, and therefore stimuli belonging to different age groups (young, middle-aged, and older adults' faces) were used. As expected, an impairment of age estimation from faces was observed in mild to moderate AD patients. However, the profile of impairment depended on the age of faces and stage of the disease. Mild AD patients presented difficulties mainly in assessing the age of middle-aged adults. In moderate disease stage, these difficulties also affected the age estimation of young adult faces. Interestingly, AD patients remained relatively good at estimating the age of older adults' faces, compared to healthy controls. PMID:25589725

  9. Combining facial dynamics with appearance for age estimation.

    PubMed

    Dibeklioglu, Hamdi; Alnajar, Fares; Ali Salah, Albert; Gevers, Theo

    2015-06-01

    Estimating the age of a human from the captured images of his/her face is a challenging problem. In general, the existing approaches to this problem use appearance features only. In this paper, we show that in addition to appearance information, facial dynamics can be leveraged in age estimation. We propose a method to extract and use dynamic features for age estimation, using a person's smile. Our approach is tested on a large, gender-balanced database with 400 subjects, with an age range between 8 and 76. In addition, we introduce a new database on posed disgust expressions with 324 subjects in the same age range, and evaluate the reliability of the proposed approach when used with another expression. State-of-the-art appearance-based age estimation methods from the literature are implemented as baseline. We demonstrate that for each of these methods, the addition of the proposed dynamic features results in statistically significant improvement. We further propose a novel hierarchical age estimation architecture based on adaptive age grouping. We test our approach extensively, including an exploration of spontaneous versus posed smile dynamics, and gender-specific age estimation. We show that using spontaneity information reduces the mean absolute error by up to 21%, advancing the state of the art for facial age estimation. PMID:25781877

  10. Age at death estimation from bone histology in Malaysian males.

    PubMed

    Nor, Faridah Mohd; Pastor, Robert F; Schutkowski, Holger

    2014-10-01

    Estimation of age from microscopic examination of human bone utilizes bone remodeling. This allows 2 regression equation to be determined in a specific population based on the variation in osteon turnover in different populations. The aim of this study was to provide age estimation for Malaysian males. Ground undecalcified cross sections were prepared from long limb bones of 50 deceased males aged between 21 and 78 years. Ten microstructural parameters were measured and subjected to multivariate regression analysis. Results showed that osteon count had the highest correlation with age (R = 0.43), and age was estimated to be within 10.94 years of the true value in 98% of males. Cross validation of the equation on 50 individuals showed close correspondence of true ages with estimated ages. Further studies are needed to validate and expand these results.

  11. Estimating the age of formation of lakes: An example from Lake Tanganyika, East African Rift system

    SciTech Connect

    Cohen, A.; Soreghan, M.J.; Scholz, C.A.

    1993-06-01

    Age estimates for ancient lakes are important for determining their histories and their rates of biotic and tectonic evolution. In the absence of dated core material from the lake`s sedimentary basement, several techniques have been used to generate such age estimates. The most common of these, herein called the reflection seismic-radiocarbon method (RSRM), combines estimates of short-term sediment-accumulation rates derived from radiocarbon-dated cores and depth-to-basement estimates derived from reflection-seismic data at or near the same locality to estimate an age to basement. Age estimates form the RSRM suggest that the structural basins of central Lake Tanganyika began to form between 9 and 12 Ma. Estimates for the northern and southern basins are younger (7 to 8 Ma and 2 to 4 Ma, respectively). The diachroneity of estimates for different segments of the lake is equivocal, and may be due to erosional loss of record in the northern and southern structural basins or to progressive opening of the rift. The RSRM age estimates for Lake Tanganyika are considerably younger than most prior estimates and clarify the extensional history of the western branch of the East African Rift system. 31 refs., 3 figs., 1 tab.

  12. Adult forensic age estimation using mandibular first molar radiographs: A novel technique

    PubMed Central

    Mathew, Deepu George; Rajesh, S; Koshi, Elizabeth; Priya, Lakshmi E; Nair, Amal S; Mohan, Aparna

    2013-01-01

    Objective: To develop an independent procedure for estimating age for Indian individuals using radiographs of multi-rooted posterior teeth with accuracy needed in forensic age prediction. Materials and Methods: Orthopantomography (OPG) was obtained for 88 subjects. The subjects were divided into two sub sets; study subset (n = 60) which were used to find regression formula to calculate the age from pulp chamber height and test subset (n = 28) which were used to test the accuracy of this formula. Results: There was a statistically significant strong correlation between chronological age and pulp chamber crown root trunk height ratio (r = −0.56; P = 0.000). The regression equation for estimating the age, derived from the study subset was estimated age = −100.920 (PCTHR) +55.415. (PCTHR is the pulp chamber crown root trunk height ratio). This equation was applied on the test subset and there was no significant difference between estimated ages and chronological ages (P = 0.639). The mean absolute error (MAE) was 6.96 years, which was within acceptable error limits for forensic age estimation (<±10 years). Conclusion: The procedure developed to estimate the age using height reduction in pulp chamber was found to be fairly accurate to perform forensic age prediction in Indian individuals. PMID:23960417

  13. Dental Age Estimation Helps Create a New Identity.

    PubMed

    De Angelis, Danilo; Gibelli, Daniele; Fabbri, Paolo; Cattaneo, Cristina

    2015-09-01

    Age estimation involves the reconstruction of age by biological parameters such as skeletal and dental development in minors, or reduction of pulp chamber in adults, to gain indications concerning the chronological age of the person. In most cases, it is needed in forensic scenarios to verify if the supposed age of an individual is correct; in exceptional cases, age estimation is instead required by judicial authorities to create a new identity usually in persons who do not remember who they are.This article aims at reporting the case of J. who was found in 2005 with signs of amnesia because he did not remember his name and age. After several unsuccessful attempts at identifying him, the judicial authority decided to assign a new identity, which was to be constructed according to the real biological data of the individual. The help of a forensic pathologist and a forensic odontologist was then requested, and age estimation was reached by applying methods for adults based on the physiological reduction of pulp chamber. Dental age estimation yielded a final result of approximately 31 years, which was the new age assigned to the person.This article shows a peculiar application of dental age estimation, which can be used not only to ascertain or deny supposed age, but is sometimes needed to create a new identity. PMID:26079404

  14. Dental Age Estimation Helps Create a New Identity.

    PubMed

    De Angelis, Danilo; Gibelli, Daniele; Fabbri, Paolo; Cattaneo, Cristina

    2015-09-01

    Age estimation involves the reconstruction of age by biological parameters such as skeletal and dental development in minors, or reduction of pulp chamber in adults, to gain indications concerning the chronological age of the person. In most cases, it is needed in forensic scenarios to verify if the supposed age of an individual is correct; in exceptional cases, age estimation is instead required by judicial authorities to create a new identity usually in persons who do not remember who they are.This article aims at reporting the case of J. who was found in 2005 with signs of amnesia because he did not remember his name and age. After several unsuccessful attempts at identifying him, the judicial authority decided to assign a new identity, which was to be constructed according to the real biological data of the individual. The help of a forensic pathologist and a forensic odontologist was then requested, and age estimation was reached by applying methods for adults based on the physiological reduction of pulp chamber. Dental age estimation yielded a final result of approximately 31 years, which was the new age assigned to the person.This article shows a peculiar application of dental age estimation, which can be used not only to ascertain or deny supposed age, but is sometimes needed to create a new identity.

  15. Accelerated aging test on LEDs life estimation

    NASA Astrophysics Data System (ADS)

    Dong, Yi; Zhang, Shu-sheng; Du, Jiang-qi

    2011-11-01

    Light-emitting diodes(LEDs) have become very attractive in different application field such as Solid State Lighting, automotive and street lights, due to their long operative lifetime, lower energy consumption etc. This paper mainly introduces the accelerated aging test, we focus our attention on the study of a life model for LEDs by relating the time to failure with the supplying condition. The constant accelerated aging experiments were firstly performed on LED samples. Process the experiment data by exploiting the degradation of LED optical power formula and degradation coefficient. Finally, the average lifetime of the samples under normal conditions was calculated via using numerical analytical method. According to data, analysis the test result and the failure mechanism of LED, provide the technical basis to improve product design and quality assurance.

  16. Precision of two methods for estimating age from burbot otoliths

    USGS Publications Warehouse

    Edwards, W.H.; Stapanian, M.A.; Stoneman, A.T.

    2011-01-01

    Lower reproductive success and older age structure are associated with many burbot (Lota lota L.) populations that are declining or of conservation concern. Therefore, reliable methods for estimating the age of burbot are critical for effective assessment and management. In Lake Erie, burbot populations have declined in recent years due to the combined effects of an aging population (&xmacr; = 10 years in 2007) and extremely low recruitment since 2002. We examined otoliths from burbot (N = 91) collected in Lake Erie in 2007 and compared the estimates of burbot age by two agers, each using two established methods (cracked-and-burned and thin-section) of estimating ages from burbot otoliths. One ager was experienced at estimating age from otoliths, the other was a novice. Agreement (precision) between the two agers was higher for the thin-section method, particularly at ages 6–11 years, based on linear regression analyses and 95% confidence intervals. As expected, precision between the two methods was higher for the more experienced ager. Both agers reported that the thin sections offered clearer views of the annuli, particularly near the margins on otoliths from burbot ages ≥8. Slides for the thin sections required some costly equipment and more than 2 days to prepare. In contrast, preparing the cracked-and-burned samples was comparatively inexpensive and quick. We suggest use of the thin-section method for estimating the age structure of older burbot populations.

  17. The estimation of age-related rates of infection from case notifications and serological data.

    PubMed Central

    Grenfell, B. T.; Anderson, R. M.

    1985-01-01

    The paper describes a maximum-likelihood method for the estimation of age-related changes in the per capita rate of infection, from case notification records or serological data. The methods are applied to records of measles incidence in the UK and USA, for which the estimated rates of infection tend to rise to a maximum value at around 10 years of age and then to decline in the older age-classes. Longer-term and seasonal trends are analysed by reference to changes in the estimated average age at infection; a statistic derived from a knowledge of the age-specific rates of infection. Future data needs in the epidemiological study of directly transmitted viral and bacterial diseases are discussed with reference to the detection and interpretation of age-dependent rates of disease transmission. PMID:4067297

  18. Comparative Analysis of Old-Age Mortality Estimations in Africa

    PubMed Central

    Bendavid, Eran; Seligman, Benjamin; Kubo, Jessica

    2011-01-01

    Background Survival to old ages is increasing in many African countries. While demographic tools for estimating mortality up to age 60 have improved greatly, mortality patterns above age 60 rely on models based on little or no demographic data. These estimates are important for social planning and demographic projections. We provide direct estimations of older-age mortality using survey data. Methods Since 2005, nationally representative household surveys in ten sub-Saharan countries record counts of living and recently deceased household members: Burkina Faso, Côte d'Ivoire, Ethiopia, Namibia, Nigeria, Swaziland, Tanzania, Uganda, Zambia, and Zimbabwe. After accounting for age heaping using multiple imputation, we use this information to estimate probability of death in 5-year intervals (5qx). We then compare our 5qx estimates to those provided by the World Health Organization (WHO) and the United Nations Population Division (UNPD) to estimate the differences in mortality estimates, especially among individuals older than 60 years old. Findings We obtained information on 505,827 individuals (18.4% over age 60, 1.64% deceased). WHO and UNPD mortality models match our estimates closely up to age 60 (mean difference in probability of death -1.1%). However, mortality probabilities above age 60 are lower using our estimations than either WHO or UNPD. The mean difference between our sample and the WHO is 5.9% (95% CI 3.8–7.9%) and between our sample is UNPD is 13.5% (95% CI 11.6–15.5%). Regardless of the comparator, the difference in mortality estimations rises monotonically above age 60. Interpretation Mortality estimations above age 60 in ten African countries exhibit large variations depending on the method of estimation. The observed patterns suggest the possibility that survival in some African countries among adults older than age 60 is better than previously thought. Improving the quality and coverage of vital information in developing countries will become

  19. Estimating Dynamical Systems: Derivative Estimation Hints from Sir Ronald A. Fisher

    ERIC Educational Resources Information Center

    Deboeck, Pascal R.

    2010-01-01

    The fitting of dynamical systems to psychological data offers the promise of addressing new and innovative questions about how people change over time. One method of fitting dynamical systems is to estimate the derivatives of a time series and then examine the relationships between derivatives using a differential equation model. One common…

  20. Dental age estimation in Egyptian children, comparison between two methods.

    PubMed

    El-Bakary, Amal A; Hammad, Shaza M; Mohammed, Fatma

    2010-10-01

    The need to estimate age of living individuals is becoming increasingly more important in both forensic science and clinical dentistry. The study of the morphological parameters of teeth on dental radiographs of adult humans is more reliable than most other methods for age estimation. Willems and Cameriere methods are newly presented methods. The aim of this work was to evaluate the applicability of using these methods for Egyptian children. Digitalized panoramas taken from 286 Egyptian children (134 boys, 152 girls) with age range from 5 to 16 years were analyzed. The seven left permanent mandibular teeth were evaluated using the two methods. The results of this research showed that dental age estimated by both methods was significantly correlated to real age. However, Willems method was slightly more accurate (98.62%) compared to Cameriere method (98.02%). Therefore, both methods can be recommended for practical application in clinical dentistry and forensic procedures on the Egyptian population.

  1. Discriminating Projections for Estimating Face Age in Wild Images

    SciTech Connect

    Tokola, Ryan A; Bolme, David S; Ricanek, Karl; Barstow, Del R; Boehnen, Chris Bensing

    2014-01-01

    We introduce a novel approach to estimating the age of a human from a single uncontrolled image. Current face age estimation algorithms work well in highly controlled images, and some are robust to changes in illumination, but it is usually assumed that images are close to frontal. This bias is clearly seen in the datasets that are commonly used to evaluate age estimation, which either entirely or mostly consist of frontal images. Using pose-specific projections, our algorithm maps image features into a pose-insensitive latent space that is discriminative with respect to age. Age estimation is then performed using a multi-class SVM. We show that our approach outperforms other published results on the Images of Groups dataset, which is the only age-related dataset with a non-trivial number of off-axis face images, and that we are competitive with recent age estimation algorithms on the mostly-frontal FG-NET dataset. We also experimentally demonstrate that our feature projections introduce insensitivity to pose.

  2. Age-dependent forest carbon sink: Estimation via inverse modeling

    NASA Astrophysics Data System (ADS)

    Zhou, Tao; Shi, Peijun; Jia, Gensuo; Dai, Yongjiu; Zhao, Xiang; Shangguan, Wei; Du, Ling; Wu, Hao; Luo, Yiqi

    2015-12-01

    Forests have been recognized to sequester a substantial amount of carbon (C) from the atmosphere. However, considerable uncertainty remains regarding the magnitude and time course of the C sink. Revealing the intrinsic relationship between forest age and C sink is crucial for reducing uncertainties in prediction of forest C sink potential. In this study, we developed a stepwise data assimilation approach to combine a process-based Terrestrial ECOsystem Regional model, observations from multiple sources, and stochastic sampling to inversely estimate carbon cycle parameters including carbon sink at different forest ages for evergreen needle-leaved forests in China. The new approach is effective to estimate age-dependent parameter of maximal light-use efficiency (R2 = 0.99) and, accordingly, can quantify a relationship between forest age and the vegetation and soil C sinks. The estimated ecosystem C sink increases rapidly with age, peaks at 0.451 kg C m-2 yr-1 at age 22 years (ranging from 0.421 to 0.465 kg C m-2 yr-1), and gradually decreases thereafter. The dynamic patterns of C sinks in vegetation and soil are significantly different. C sink in vegetation first increases rapidly with age and then decreases. C sink in soil, however, increases continuously with age; it acts as a C source when the age is less than 20 years, after which it acts as a sink. For the evergreen needle-leaved forest, the highest C sink efficiency (i.e., C sink per unit net primary productivity) is approximately 60%, with age between 11 and 43 years. Overall, the inverse estimation of carbon cycle parameters can make reasonable estimates of age-dependent C sequestration in forests.

  3. Age estimation using maxillary central incisors: A radiographic study

    PubMed Central

    Agarwal, Nitin; Ahuja, Parul; Sinha, Abhishek; Singh, Anil

    2012-01-01

    Background: In the field of forensic dentistry, secondary changes in teeth with advancing age have been used as reliable predictors of age in various studies. Aim: The purpose of the present study was to present a method for assessing the chronological age based on the relationship between age and morphological parameters of maxillary central incisors. Materials and Methods: Fifty subjects between 20-70 years of age were included in the study. Intraoral periapical radiographs were taken in relation to maxillary central incisors using paralleling technique. The following measurements were recorded: lengths of tooth, pulp, root and width of root and pulp at three different points. Regression formulas were used to calculate the dental age. Results: The mean estimated age showed no statistically significant difference from the actual mean age (P > 0.05). Also, maximum difference was seen for root length variable (-1.035 ± 1.86 years). PMID:23741151

  4. Estimation of gestational age from gall-bladder length.

    PubMed

    Udaykumar, K; Udaykumar, Padmaja; Nagesh, K R

    2016-01-01

    Establishing a precise duration of gestation is vital in situations such as infanticide and criminal abortions. The present study attempted to estimate the gestational age of the foetus from gall-bladder length. Foetuses of various gestational age groups were dissected, and the length of the gall bladder was measured. The results were analysed, and a substantial degree of correlation was statistically confirmed. This novel method is helpful when the foetus is fragmented, putrefied or eviscerated, where this method can be used as an additional parameter to improve the accuracy of foetal age estimation. PMID:25990829

  5. Updating UK estimates of age, sex and period specific cumulative constant tar cigarette consumption per adult

    PubMed Central

    Forey, B.; Lee, P.; Fry, J.

    1998-01-01

    BACKGROUND—In 1993 we presented age and sex specific estimates of cumulative constant tar cigarette consumption (CCTCC) per adult for five year periods to 1986-90. These were derived from annual surveys conducted for the Tobacco Manufacturers' Association (TMA) since 1946, extrapolated back to 1891 for men and to 1921 for women and corrected for the decline in average (machine smoked) tar levels. We now provide estimates for 1991-5.
METHODS—TMA surveys having ceased, 1991-5 estimates of manufactured cigarette consumption per adult (MCA) were derived from the General Household Survey (GHS) and corrected for the continuing decline in tar. These estimates were divided by 0.75 (men) and 0.80 (women), based on a comparison of GHS and TMA data for 1971-90, to allow accumulation with the TMA derived estimates prior to 1991.
RESULTS—For both sexes the GHS/TMA ratio of MCA varied little by age or five year period, justifying the use of the correction factors when adjusting GHS estimates for 1991-95. TMA estimates were higher than GHS estimates as only TMA sales-corrected their data for understatement of smoking and the surveys differed in questions on handrolled cigarette smoking. The 1991-95 data confirm the continuing decline in CCTCC at all ages in men. Women show a less steep decline for ages 30-64 and an increase for ages 65-84.
CONCLUSION—The GHS data can validly be used to update the CCTCC estimates. Some reservations about the use of CCTCC are discussed.

 PMID:10193376

  6. Accuracy of methods of age estimation in predicting dental age of preadolescents in South Indian children.

    PubMed

    Balla, Sudheer B; Venkat Baghirath, P; Hari Vinay, B; Vijay Kumar, J; Babu, D B Gandhi

    2016-10-01

    Age estimation in forensic context is of prime importance for criminal, civil and administrative laws. The objective of this study is to test the accuracy of 3 methods of age estimation in South Indian children (preadolescents) aged between 7 and 15 years. It is a retrospective study of orthopantamograms (OPGs) of 150 children among which 79 were boys and 71 were girls. Cameriere's, Willems and Acharya's age estimation methods were used to predict chronological age. Paired t-test was used to compare all data and relationships between continuous variables were examined using Pearson's correlation coefficient. The Cameriere's method Underestimated the real age by -0.62 years in boys and -0.54 years in girls. Both Willems and Acharya's methods overestimated age in both sexes by 0.41, 0.18 years and 0.41, 0.47 years respectively.

  7. Accuracy of methods of age estimation in predicting dental age of preadolescents in South Indian children.

    PubMed

    Balla, Sudheer B; Venkat Baghirath, P; Hari Vinay, B; Vijay Kumar, J; Babu, D B Gandhi

    2016-10-01

    Age estimation in forensic context is of prime importance for criminal, civil and administrative laws. The objective of this study is to test the accuracy of 3 methods of age estimation in South Indian children (preadolescents) aged between 7 and 15 years. It is a retrospective study of orthopantamograms (OPGs) of 150 children among which 79 were boys and 71 were girls. Cameriere's, Willems and Acharya's age estimation methods were used to predict chronological age. Paired t-test was used to compare all data and relationships between continuous variables were examined using Pearson's correlation coefficient. The Cameriere's method Underestimated the real age by -0.62 years in boys and -0.54 years in girls. Both Willems and Acharya's methods overestimated age in both sexes by 0.41, 0.18 years and 0.41, 0.47 years respectively. PMID:27428567

  8. Cognitive estimation in aged patients with major depressive disorder.

    PubMed

    Barabassy, Agota; Beinhoff, Ulrike; Riepe, Matthias W

    2010-03-30

    In everyday life, we often estimate rather than know. It was the goal of this study to assess the effect of depressed mood on cognitive estimation in old age. Cognitive estimation was performed in 44 subjects with major depressive disorder (MDD; DSM-IV) and 48 age-matched healthy subjects (HS). Severity of depressive symptoms was rated with the Montgomery-Asberg Depression Rating Scale (MADRS, mean=18.6+/-S.D. 4.85). Estimation tasks comprised the dimensions length (coin diameter), weight (pile of paper), quantity (number of marbles in a glass jar), and time (estimation of time it takes for a marble to roll down a marble track both before and after having observed it). Other than the procedure followed in previous tests on cognitive estimation, the tasks were performed by observing objects rather than pictures thereof. MDD patients overestimated time (before and after observation) and underestimated quantity. Cognitive estimation was not correlated to measures of frontal functioning or semantic knowledge. We conclude that MDD patients in old age are impaired to some extent in cognitive estimation and in the ability to correct themselves, deficits that are likely to affect the performance of everyday activities. PMID:20064666

  9. Estimation and evidence in forensic anthropology: age-at-death.

    PubMed

    Konigsberg, Lyle W; Herrmann, Nicholas P; Wescott, Daniel J; Kimmerle, Erin H

    2008-05-01

    A great deal has previously been written about the use of skeletal morphological changes in estimating ages-at-death. This article looks in particular at the pubic symphysis, as it was historically one of the first regions to be described in the literature on age estimation. Despite the lengthy history, the value of the pubic symphysis in estimating ages and in providing evidence for putative identifications remains unclear. This lack of clarity primarily stems from the fact that rather ad hoc statistical methods have been applied in previous studies. This article presents a statistical analysis of a large data set (n = 1766) of pubic symphyseal scores from multiple contexts, including anatomical collections, war dead, and victims of genocide. The emphasis is in finding statistical methods that will have the correct "coverage."Coverage" means that if a method has a stated coverage of 50%, then approximately 50% of the individuals in a particular pubic symphyseal stage should have ages that are between the stated age limits, and that approximately 25% should be below the bottom age limit and 25% above the top age limit. In a number of applications it is shown that if an appropriate prior age-at-death distribution is used, then "transition analysis" will provide accurate "coverages," while percentile methods, range methods, and means (+/-standard deviations) will not. Even in cases where there are significant differences in the mean ages-to-transition between populations, the effects on the stated age limits for particular "coverages" are minimal. As a consequence, more emphasis needs to be placed on collecting data on age changes in large samples, rather than focusing on the possibility of inter-population variation in rates of aging.

  10. Estimation of Stability and Control Derivatives of an F-15

    NASA Technical Reports Server (NTRS)

    Smith, Mark; Moes, Tim

    2006-01-01

    A technique for real-time estimation of stability and control derivatives (derivatives of moment coefficients with respect to control-surface deflection angles) was used to support a flight demonstration of a concept of an indirect-adaptive intelligent flight control system (IFCS). Traditionally, parameter identification, including estimation of stability and control derivatives, is done post-flight. However, for the indirect-adaptive IFCS concept, parameter identification is required during flight so that the system can modify control laws for a damaged aircraft. The flight demonstration was carried out on a highly modified F-15 airplane (see Figure 1). The main objective was to estimate the stability and control derivatives of the airplane in nearly real time. A secondary goal was to develop a system to automatically assess the quality of the results, so as to be able to tell a learning neural network which data to use. Parameter estimation was performed by use of Fourier-transform regression (FTR) a technique developed at NASA Langley Research Center. FTR is an equation- error technique that operates in the frequency domain. Data are put into the frequency domain by use of a recursive Fourier transform for a discrete frequency set. This calculation simplifies many subsequent calculations, removes biases, and automatically filters out data beyond the chosen frequency range. FTR as applied here was tailored to work with pilot inputs, which produce correlated surface positions that prevent accurate parameter estimates, by replacing half the derivatives with predicted values. FTR was also set up to work only on a recent window of data, to accommodate changes in flight condition. A system of confidence measures was developed to identify quality-parameter estimates that a learning neural network could use. This system judged the estimates primarily on the basis of their estimated variances and of the level of aircraft response. The resulting FTR system was implemented

  11. Influence of sectioning location on age estimates from common carp dorsal spines

    USGS Publications Warehouse

    Watkins, Carson J.; Klein, Zachary B.; Terrazas, Marc M.; Quist, Michael

    2015-01-01

    Dorsal spines have been shown to provide precise age estimates for Common CarpCyprinus carpio and are commonly used by management agencies to gain information on Common Carp populations. However, no previous studies have evaluated variation in the precision of age estimates obtained from different sectioning locations along Common Carp dorsal spines. We evaluated the precision, relative readability, and distribution of age estimates obtained from various sectioning locations along Common Carp dorsal spines. Dorsal spines from 192 Common Carp were sectioned at the base (section 1), immediately distal to the basal section (section 2), and at 25% (section 3), 50% (section 4), and 75% (section 5) of the total length of the dorsal spine. The exact agreement and within-1-year agreement among readers was highest and the coefficient of variation lowest for section 2. In general, age estimates derived from sections 2 and 3 had similar age distributions and displayed the highest concordance in age estimates with section 1. Our results indicate that sections taken at ≤ 25% of the total length of the dorsal spine can be easily interpreted and provide precise estimates of Common Carp age. The greater consistency in age estimates obtained from section 2 indicates that by using a standard sectioning location, fisheries scientists can expect age-based estimates of population metrics to be more comparable and thus more useful for understanding Common Carp population dynamics.

  12. Ultrasound Algorithm Derivation for Soil Moisture Content Estimation

    NASA Technical Reports Server (NTRS)

    Belisle, W.R.; Metzl, R.; Choi, J.; Aggarwal, M. D.; Coleman, T.

    1997-01-01

    Soil moisture content can be estimated by evaluating the velocity at which sound waves travel through a known volume of solid material. This research involved the development of three soil algorithms relating the moisture content to the velocity at which sound waves moved through dry and moist media. Pressure and shear wave propagation equations were used in conjunction with soil property descriptions to derive algorithms appropriate for describing the effects of moisture content variation on the velocity of sound waves in soils with and without complete soil pore water volumes, An elementary algorithm was used to estimate soil moisture contents ranging from 0.08 g/g to 0.5 g/g from sound wave velocities ranging from 526 m/s to 664 m/s. Secondary algorithms were also used to estimate soil moisture content from sound wave velocities through soils with pores that were filled predominantly with air or water.

  13. Aging, Transition, and Estimating the Global Burden of Disease

    PubMed Central

    Seligman, Benjamin J.; Cullen, Mark R.; Horwitz, Ralph I.

    2011-01-01

    Background The World Health Organization's Global Burden of Disease (GBD) reports are an important tool for global health policy makers, however the accuracy of estimates for countries undergoing an epidemiologic transition is unclear. We attempted to validate the life table model used to generate estimates for all-cause mortality in developing countries. Methods and Results Data were obtained for males and females from the Human Mortality Database for all countries with available data every ten years from 1900 to 2000. These provided inputs for the GBD life table model and served as comparison observed data. Above age sixty model estimates of survival for both sexes differed substantially from those observed. Prior to the year 1960 for males and 1930 for females, estimated survival tended to be greater than observed; following 1960 for both males and females estimated survival tended to be less than observed. Viewing observed and estimated survival separately, observed survival past sixty increased over the years considered. For males, the increase was from a mean (sd) probability of 0.22 (0.06) to 0.46 (0.1). For females, the increase was from 0.26 (0.06) to 0.65 (0.08). By contrast, estimated survival past sixty decreased over the same period. Among males, estimated survival probability declined from 0.54 (0.2) to 0.09 (0.06). Among females, the decline was from 0.36 (0.12) to 0.15 (0.08). Conclusions These results show that the GBD mortality model did not accurately estimate survival at older ages as developed countries transitioned in the twentieth century and may be similarly flawed in developing countries now undergoing transition. Estimates of the size of older-age populations and their attributable disease burden should be reconsidered. PMID:21629652

  14. Statistical estimation of mineral age by K-Ar method

    SciTech Connect

    Vistelius, A.B.; Drubetzkoy, E.R.; Faas, A.V. )

    1989-11-01

    Statistical estimation of age of {sup 40}Ar/{sup 40}K ratios may be considered a result of convolution of uniform and normal distributions with different weights for different minerals. Data from Gul'shad Massif (Nearbalkhash, Kazakhstan, USSR) indicate that {sup 40}Ar/{sup 40}K ratios reflecting the intensity of geochemical processes can be resolved using convolutions. Loss of {sup 40}Ar in biotites is shown whereas hornblende retained the original content of {sup 40}Ar throughout the geological history of the massif. Results demonstrate that different estimation methods must be used for different minerals and different rocks when radiometric ages are employed for dating.

  15. Age estimation charts for a modern Australian population.

    PubMed

    Blenkin, Matthew; Taylor, Jane

    2012-09-10

    Calculation of the biological age of an individual has application in many fields of dentistry. It can be used to determine the appropriate timing of interventionist treatment for example in orthodontics; to analyse the developmental stage of an individual relative to the general population in the management of genetic or congenital conditions which disturb growth; and to estimate the age of a living or deceased person for forensic purposes. Many of the techniques used to estimate age can be quite time consuming to complete. This time component is a major disadvantage in a forensic context when age estimations in mass disasters are required as part of the post-mortem examination process. Consequently, forensic practitioners have tended to use the simpler but less reliable atlas style techniques of Schour and Massler and Ubelaker in these situations. For mass disaster situations, such as the recent Victorian Bushfires, it would be advantageous to have access to Australian specific data in the convenient Schour and Massler format. This project reinterpreted the Australian data previously collected by Blenkin and other relevant studies and applied it to a schematic similar to that of Ubelaker to develop a reliable, convenient and contemporary reference for use in age estimation.

  16. Objective measurement of shade color in age estimation

    PubMed Central

    Vaidya, Sharad; Ahuja, Nitin; Bajaj, Puneet; Kapoor, Charu; Sabarwal, Robin; Rajpal, Karan

    2015-01-01

    Introduction: Age estimation is an important subspecialty of forensic medicine. Dental hard tissues are highly resistant to degradation and putrefaction. Enamel is translucent and varies in color from light yellow to grey white. The color of the teeth has been reported to be affected by chronological age. Enamel color may also depend on environmental factors viz. diet, occupational habits, vitamin deficiencies, fluoride level in drinking water etc., It has been found that color changes in dentin vary from white to yellow. Studies have been done to measure the dentin color for age estimation. Aim: To find a correlation between the enamel color and chronological age and secondly to estimate the age of an individual from enamel color. Material and Methods: A total of 300 patients visiting the outpatient department of oral medicine and radiology were selected. Out of those, 150 were men and 150 women. The patients were divided into V groups based on the age. A thorough case history was taken for all the patients. Maxillary Central and Lateral incisor was used for the estimation of shade. The enamel color was evaluated using a VITA classical shade guide. Statistical Analysis: Data were exported to an Excel spread sheet and statistical analysis was performed using the SPSS. Linear regression analysis was used to find correlations between age and enamel shade. Results: In the group 1 and 2 i.e. from 15 to 36 years, the shades A 2 and B 2 (reddish hue) was found to be most common. While in the group 3 and 4, shades ranged from A 3 to B 3 (brownish to yellowish hue). In the patients above 59 years i.e. group 5 the enamel shade with greyish hue was found to be most common. Conclusion: Age determination using enamel color can be tried in forensic cases in the identification of individuals with no birth records. PMID:26816455

  17. A Bayesian estimation of the helioseismic solar age

    NASA Astrophysics Data System (ADS)

    Bonanno, A.; Fröhlich, H.-E.

    2015-08-01

    Context. The helioseismic determination of the solar age has been a subject of several studies because it provides us with an independent estimation of the age of the solar system. Aims: We present the Bayesian estimates of the helioseismic age of the Sun, which are determined by means of calibrated solar models that employ different equations of state and nuclear reaction rates. Methods: We use 17 frequency separation ratios r02(n) = (νn,l = 0-νn-1,l = 2)/(νn,l = 1-νn-1,l = 1) from 8640 days of low-ℓBiSON frequencies and consider three likelihood functions that depend on the handling of the errors of these r02(n) ratios. Moreover, we employ the 2010 CODATA recommended values for Newton's constant, solar mass, and radius to calibrate a large grid of solar models spanning a conceivable range of solar ages. Results: It is shown that the most constrained posterior distribution of the solar age for models employing Irwin EOS with NACRE reaction rates leads to t⊙ = 4.587 ± 0.007 Gyr, while models employing the Irwin EOS and Adelberger, et al. (2011, Rev. Mod. Phys., 83, 195) reaction rate have t⊙ = 4.569 ± 0.006 Gyr. Implementing OPAL EOS in the solar models results in reduced evidence ratios (Bayes factors) and leads to an age that is not consistent with the meteoritic dating of the solar system. Conclusions: An estimate of the solar age that relies on an helioseismic age indicator such as r02(n) turns out to be essentially independent of the type of likelihood function. However, with respect to model selection, abandoning any information concerning the errors of the r02(n) ratios leads to inconclusive results, and this stresses the importance of evaluating the trustworthiness of error estimates.

  18. Accurate Satellite-Derived Estimates of Tropospheric Ozone Radiative Forcing

    NASA Technical Reports Server (NTRS)

    Joiner, Joanna; Schoeberl, Mark R.; Vasilkov, Alexander P.; Oreopoulos, Lazaros; Platnick, Steven; Livesey, Nathaniel J.; Levelt, Pieternel F.

    2008-01-01

    Estimates of the radiative forcing due to anthropogenically-produced tropospheric O3 are derived primarily from models. Here, we use tropospheric ozone and cloud data from several instruments in the A-train constellation of satellites as well as information from the GEOS-5 Data Assimilation System to accurately estimate the instantaneous radiative forcing from tropospheric O3 for January and July 2005. We improve upon previous estimates of tropospheric ozone mixing ratios from a residual approach using the NASA Earth Observing System (EOS) Aura Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) by incorporating cloud pressure information from OMI. Since we cannot distinguish between natural and anthropogenic sources with the satellite data, our estimates reflect the total forcing due to tropospheric O3. We focus specifically on the magnitude and spatial structure of the cloud effect on both the shortand long-wave radiative forcing. The estimates presented here can be used to validate present day O3 radiative forcing produced by models.

  19. Open-cluster density profiles derived using a kernel estimator

    NASA Astrophysics Data System (ADS)

    Seleznev, Anton F.

    2016-03-01

    Surface and spatial radial density profiles in open clusters are derived using a kernel estimator method. Formulae are obtained for the contribution of every star into the spatial density profile. The evaluation of spatial density profiles is tested against open-cluster models from N-body experiments with N = 500. Surface density profiles are derived for seven open clusters (NGC 1502, 1960, 2287, 2516, 2682, 6819 and 6939) using Two-Micron All-Sky Survey data and for different limiting magnitudes. The selection of an optimal kernel half-width is discussed. It is shown that open-cluster radius estimates hardly depend on the kernel half-width. Hints of stellar mass segregation and structural features indicating cluster non-stationarity in the regular force field are found. A comparison with other investigations shows that the data on open-cluster sizes are often underestimated. The existence of an extended corona around the open cluster NGC 6939 was confirmed. A combined function composed of the King density profile for the cluster core and the uniform sphere for the cluster corona is shown to be a better approximation of the surface radial density profile.The King function alone does not reproduce surface density profiles of sample clusters properly. The number of stars, the cluster masses and the tidal radii in the Galactic gravitational field for the sample clusters are estimated. It is shown that NGC 6819 and 6939 are extended beyond their tidal surfaces.

  20. A revised burial dose estimation procedure for optical dating of youngand modern-age sediments

    USGS Publications Warehouse

    Arnold, L.J.; Roberts, R.G.; Galbraith, R.F.; DeLong, S.B.

    2009-01-01

    , since these age models are better suited to the statistical properties of typical single-grain and multi-grain single-aliquot De datasets. However, the unique error properties of modern-age samples, combined with the problems of calculating natural logarithms of negative or zero-Gy De values, mean that the un-logged versions of the central and minimum age models currently offer the most suitable means of deriving accurate burial dose estimates for very young and modern-age samples. ?? 2009 Elsevier Ltd. All rights reserved.

  1. Estimation of age from development and eruption of teeth

    PubMed Central

    Manjunatha, B. S.; Soni, Nishit K.

    2014-01-01

    The developing dentition is used to assess maturity and estimate the age in many disciplines including anthropology, archeology, forensic science, pediatric dentistry and orthodontics. There is evidence that dental development is less effected than skeletal development by malnutrition and hormonal disorders. There are two methods of dental age assessment, radiographically and by clinically visualization of eruption of teeth. The clinical method to assess dental age is based on the emergence of teeth in the mouth. This method is more suitable since it does not require any special equipment, expertise and is more economical. Tooth formation is the best choice for estimating the age as variations are less as compared to other development factors. Eruption of teeth is one of the changes observed easily among the various dynamic changes that occur from the formation of teeth to the final shedding of teeth. The times of eruption of teeth are fairly constant and this can be made use of in ascertaining the average age of eruption of the tooth. Assessment of age of an individual by examination of teeth is one of the accepted methods of age determination. PMID:25125911

  2. Estimation of Rotary Stability Derivatives at Subsonic and Transonic Speeds

    NASA Technical Reports Server (NTRS)

    Tobak, Murray; Lessing, Henry C.

    1961-01-01

    The first part of this paper pertains to the estimation of subsonic rotary stability derivatives of wings. The unsteady potential flow problem is solved by a superposition of steady flow solutions. Numerical results for the damping coefficients of triangular wings are presented as functions of aspect ratio and Mach number, and are compared with experimental results over the Mach number range 0 to 1. In the second part, experimental results are used. to point out a close correlation between the nonlinear variations with angle of attack of the static pitching-moment curve slope and the damping-in-pitch coefficient. The underlying basis for the correlation is found as a result of an analysis in which the indicial function concept and. the principle of super-position are adapted to apply to the nonlinear problem. The form of the result suggests a method of estimating nonlinear damping coefficients from results of static wind-tunnel measurements.

  3. Evaluation of age estimation technique: testing traits of the acetabulum to estimate age at death in adult males.

    PubMed

    Calce, Stephanie E; Rogers, Tracy L

    2011-03-01

    This study evaluates the accuracy and precision of a skeletal age estimation method, using the acetabulum of 100 male ossa coxae from the Grant Collection (GRO) at the University of Toronto, Canada. Age at death was obtained using Bayesian inference and a computational application (IDADE2) that requires a reference population, close in geographic and temporal distribution to the target case, to calibrate age ranges from scores generated by the technique. The inaccuracy of this method is 8 years. The direction of bias indicates the acetabulum technique tends to underestimate age. The categories 46-65 and 76-90 years exhibit the smallest inaccuracy (0.2), suggesting that this method may be appropriate for individuals over 40 years. Eighty-three percent of age estimates were ±12 years of known age; 79% were ±10 years of known age; and 62% were ±5 years of known age. Identifying a suitable reference population is the most significant limitation of this technique for forensic applications.

  4. Secondary Forest Age and Tropical Forest Biomass Estimation Using TM

    NASA Technical Reports Server (NTRS)

    Nelson, R. F.; Kimes, D. S.; Salas, W. A.; Routhier, M.

    1999-01-01

    The age of secondary forests in the Amazon will become more critical with respect to the estimation of biomass and carbon budgets as tropical forest conversion continues. Multitemporal Thematic Mapper data were used to develop land cover histories for a 33,000 Square kM area near Ariquemes, Rondonia over a 7 year period from 1989-1995. The age of the secondary forest, a surrogate for the amount of biomass (or carbon) stored above-ground, was found to be unimportant in terms of biomass budget error rates in a forested TM scene which had undergone a 20% conversion to nonforest/agricultural cover types. In such a situation, the 80% of the scene still covered by primary forest accounted for over 98% of the scene biomass. The difference between secondary forest biomass estimates developed with and without age information were inconsequential relative to the estimate of biomass for the entire scene. However, in futuristic scenarios where all of the primary forest has been converted to agriculture and secondary forest (55% and 42% respectively), the ability to age secondary forest becomes critical. Depending on biomass accumulation rate assumptions, scene biomass budget errors on the order of -10% to +30% are likely if the age of the secondary forests are not taken into account. Single-date TM imagery cannot be used to accurately age secondary forests into single-year classes. A neural network utilizing TM band 2 and three TM spectral-texture measures (bands 3 and 5) predicted secondary forest age over a range of 0-7 years with an RMSE of 1.59 years and an R(Squared) (sub actual vs predicted) = 0.37. A proposal is made, based on a literature review, to use satellite imagery to identify general secondary forest age groups which, within group, exhibit relatively constant biomass accumulation rates.

  5. Precise attention filters for Weber contrast derived from centroid estimations.

    PubMed

    Drew, Stefanie A; Chubb, Charles F; Sperling, George

    2010-01-01

    How well can observers selectively attend only to dots that are lighter or darker than the background when all dot intensities are present? Observers estimated centroids of briefly flashed, sparse clouds of 8 or 16 dots, ranging in intensity from dark black to bright white on a gray background. Attention instructions were to equally weight: (i) dots brighter than the background, assigning zero weight to others; (ii) dots darker than the background, assigning zero weight to others; (iii) all dots. For each observer, a quantitative estimate of the operational attention filter (the weight exerted in the centroid estimates as a function of dot intensity) was derived for each attention instruction in each dot condition. Attended dots typically have 4× the weights of unattended dots. Whereas observers performed remarkably well in estimating centroids and achieving the three required attention filters, they achieved higher accuracy when equally weighing all dots than when selectively attending to dots of only one contrast polarity. Although their attention filters are similar, individual observers use significantly different parameters in their centroid computations. The complete model of performance enables perceptual measurements of observers' attention filters for shades of gray that are as accurate as physical measurements of color filters.

  6. Inferences about ungulate population dynamics derived from age ratios

    USGS Publications Warehouse

    Harris, N.C.; Kauffman, M.J.; Mills, L.S.

    2008-01-01

    Age ratios (e.g., calf:cow for elk and fawn:doe for deer) are used regularly to monitor ungulate populations. However, it remains unclear what inferences are appropriate from this index because multiple vital rate changes can influence the observed ratio. We used modeling based on elk (Cervus elaphus) life-history to evaluate both how age ratios are influenced by stage-specific fecundity and survival and how well age ratios track population dynamics. Although all vital rates have the potential to influence calf:adult female ratios (i.e., calf:xow ratios), calf survival explained the vast majority of variation in calf:adult female ratios due to its temporal variation compared to other vital rates. Calf:adult female ratios were positively correlated with population growth rate (??) and often successfully indicated population trajectories. However, calf:adult female ratios performed poorly at detecting imposed declines in calf survival, suggesting that only the most severe declines would be rapidly detected. Our analyses clarify that managers can use accurate, unbiased age ratios to monitor arguably the most important components contributing to sustainable ungulate populations, survival rate of young and ??. However, age ratios are not useful for detecting gradual declines in survival of young or making inferences about fecundity or adult survival in ungulate populations. Therefore, age ratios coupled with independent estimates of population growth or population size are necessary to monitor ungulate population demography and dynamics closely through time.

  7. Estimating alluvial fan surface ages using Landsat 8 multispectral imagery

    NASA Astrophysics Data System (ADS)

    D'Arcy, Mitch; Mason, Philippa J.; Whittaker, Alexander C.; Roda Boluda, Duna C.

    2015-04-01

    Accurate exposure age models are now essential for geomorphological and stratigraphic field research, and generally depend on laboratory analyses such as radiocarbon, cosmogenic nuclide or luminescence approaches. However, these techniques cannot be deployed in situ in the field, meaning other methods are needed to produce a preliminary age model, map depositional surfaces of different ages, and select sampling sites for the types of laboratory analyses outlined above. With the widespread availability of high-resolution multispectral imagery, a promising approach is to use remotely sensed data to discriminate depositional surfaces with different ages. Here, we use new Landsat 8 Operational Land Imager (OLI) multispectral imagery to characterise the reflectance of 35 alluvial fan surfaces in the semi-arid Owens Valley, California. These surfaces have been mapped in detail in the field, have similar granitic compositions, and have well-constrained exposure ages ranging from modern to ~ 125 ka, measured using a high density of 10-Be cosmogenic nuclide samples. We identify a clear age signal recorded in the spectral properties of these surfaces. With increasing exposure age, there is a predictable redshift effect in the reflectance of the surfaces across the visible and short-wave infrared spectrum. Simple calculations, such as the brightness ratio of red/blue wavelengths, produce sensitive power law relationships with exposure age for at least 125 ka, meaning Landsat 8 imagery can be used to estimate surface exposure age remotely, at least in this calibrated dryland location. The ability to remotely sense exposure age has useful implications for field mapping, selecting suitable sampling sites for laboratory-based exposure age techniques, and correlating existing age constraints to previously un-sampled surfaces. We present the uncertainties associated with this spectral approach to exposure dating, evaluate its likely physical origins, and discuss its applicability

  8. Dental age estimation using Willems method: A digital orthopantomographic study

    PubMed Central

    Mohammed, Rezwana Begum; Krishnamraju, P. V.; Prasanth, P. S.; Sanghvi, Praveen; Lata Reddy, M. Asha; Jyotsna, S.

    2014-01-01

    In recent years, age estimation has become increasingly important in living people for a variety of reasons, including identifying criminal and legal responsibility, and for many other social events such as a birth certificate, marriage, beginning a job, joining the army, and retirement. Objectives: The aim of this study was to assess the developmental stages of left seven mandibular teeth for estimation of dental age (DA) in different age groups and to evaluate the possible correlation between DA and chronological age (CA) in South Indian population using Willems method. Materials and Methods: Digital Orthopantomogram of 332 subjects (166 males, 166 females) who fit the study and the criteria were obtained. Assessment of mandibular teeth (from central incisor to the second molar on left quadrant) development was undertaken and DA was assessed using Willems method. Results and Discussion: The present study showed a significant correlation between DA and CA in both males (r = 0.71 and females (r = 0.88). The overall mean difference between the estimated DA and CA for males was 0.69 ± 2.14 years (P < 0.001) while for females, it was 0.08 ± 1.34 years (P > 0.05). Willems method underestimated the mean age of males by 0.69 years and females by 0.08 years and showed that females mature earlier than males in selected population. The mean difference between DA and CA according to Willems method was 0.39 years and is statistically significant (P < 0.05). Conclusion: This study showed significant relation between DA and CA. Thus, digital radiographic assessment of mandibular teeth development can be used to generate mean DA using Willems method and also the estimated age range for an individual of unknown CA. PMID:25191076

  9. Age estimation in archaeological skeletal remains: evaluation of four non-destructive age calculation methods.

    PubMed

    Vodanović, M; Dumančić, J; Galić, I; Savić Pavičin, I; Petrovečki, M; Cameriere, R; Brkić, H

    2011-12-01

    Estimation of age at death is an essential part of reconstructing information from skeletal material. The aim of the investigation was to reconstruct the chronological age of an archaeological sample from Croatia using cranial skeletal remains as well as to make an evaluation of the methods used for age estimation. For this purpose, four age calculation methods were used: palatal suture closure, occlusal tooth wear, tooth root translucency and pulp/tooth area ratio. Cramer's V test was used to test the association between the age calculation methods. Cramer's V test showed high association (0.677) between age determination results using palatal suture closure and occlusal tooth wear, and low association (0.177) between age determination results using palatal suture closure and pulp/tooth area ratio. Simple methods like palatal suture closure can provide data about age at death for large number of individuals, but with less accuracy. More complex methods which require qualified and trained personnel can provide data about age for a smaller number of individuals, but with more accuracy. Using different (both simple and complex) age calculation methods in archaeological samples can raise the level of confidence and percentage of success in determining age.

  10. Graphical and Demographic Synopsis of the Captive Cohort Method for Estimating Population Age Structure in the Wild

    PubMed Central

    Carey, James R.; Müller, Hans-Georg; Wang, Jane-Ling; Papadopoulos, Nikos; Diamantidis, Alexis; Kouloussis, Nikos

    2014-01-01

    The purpose of this paper is to complement the literature concerned with the captive cohort method for estimating age structure including (1) graphic techniques to visualize and thus better understand the underlying life table identity in which the age structure of a stationary population equals the time-to-death distribution of the individuals within it; (2) re-derive the basic model for estimating age structure in non-stationary population in demographic rather than statistical notation; and (3) describe a simplified method for estimating changes in the mean age of a wild population. PMID:22776134

  11. Conventional versus digital approach for measuring dentin translucency in forensic age estimation

    PubMed Central

    Chopra, Varun; Thodasam, Gopal; Ahmad, Zeeshan Heera; Singh, Simranjit; Rajawat, Indresh; Gupta, Sonal

    2015-01-01

    Background: Root dentine translucency remains the method of choice providing the most accurate results for age estimation. Conventionally, translucency is measured using calipers. In recent times, computer-based methods are proposed, which require the use of custom-built software programs. Aims and Objectives: The aim was to use a digital method to measure dentinal translucency on sectioned teeth and to compare digital measurements to conventionally obtained translucency measurements. Materials and Methods: A total of 200 extracted permanent teeth were collected and were sectioned to a thickness of 250 μm. Translucency measurements were obtained using the digital method and compared with those obtained using a caliper. Results: Correlation coefficients of translucency measurements to age were statistically significant for both methods (P < 0.001), although marginally higher correlation was observed for the conventional method (r = 0.612). Application of derived linear regression equations on an independent sample (n = 25) suggested that conventional approach is marginally better in estimating age to within 5 years of the actual age, both the methods are similar in assessing age within 5-10 years of the actual age, and digital approach is marginally better in estimating age beyond 10 years of actual age. Conclusion: The translucency measurements obtained by the two methods were identical, with no clear superiority of one method over the other. PMID:25810651

  12. Porosity estimation of aged mortar using a micromechanical model.

    PubMed

    Hernández, M G; Anaya, J J; Sanchez, T; Segura, I

    2006-12-22

    Degradation of concrete structures located in high humidity atmospheres or under flowing water is a very important problem. In this study, a method for ultrasonic non-destructive characterization in aged mortar is presented. The proposed method makes a prediction of the behaviour of aged mortar accomplished with a three phase micromechanical model using ultrasonic measurements. Aging mortar was accelerated by immersing the probes in ammonium nitrate solution. Both destructive and non-destructive characterization of mortar was performed. Destructive tests of porosity were performed using a vacuum saturation method and non-destructive characterization was carried out using ultrasonic velocities. Aging experiments show that mortar degradation not only involves a porosity increase, but also microstructural changes in the cement matrix. Experimental results show that the estimated porosity using the proposed non-destructive methodology had a comparable performance to classical destructive techniques.

  13. Estimating carbon stocks based on forest volume-age relationship

    NASA Astrophysics Data System (ADS)

    Hangnan, Y.; Lee, W.; Son, Y.; Kwak, D.; Nam, K.; Moonil, K.; Taesung, K.

    2012-12-01

    This research attempted to estimate potential change of forest carbon stocks between 2010 and 2110 in South Korea, using the forest cover map and National Forest Inventory (NFI) data. Allometric functions (logistic regression models) of volume-age relationships were developed to estimate carbon stock change during upcoming 100 years for Pinus densiflora, Pinus koraiensis, Pinus rigida, Larix kaempferi,and Quercus spp. The current forest volume was estimated with the developed regression model and 4th forest cover map. The future volume was predicted by developed volume-age models with adding n years to current age. As a result, we found that the total forest volume would increase from 126.89 m^3/ha to 246.61 m^3/ha and the carbon stocks would increase from 90.55 Mg C ha^(-1) to 174.62 Mg C ha^(-1) during 100 years when current forest remains unchanged. The carbon stocks would increase by approximately 0.84 Mg C ha^(-1) yr^(-1), which has high value if considering other northern countries' (Canada, Russia, China) -0.10 ~ 0.28 Mg C ha^(-1) yr^(-1) in pervious study. This can be attributed to the fact that mixed forest and bamboo forest in this study did not considered. Moreover, it must be influenced by that the change of carbon stocks was estimated without the consideration of mortality, thinning, and tree species' change in this study. ;

  14. An assessment of GLOBOCAN methods for deriving national estimates of cancer incidence

    PubMed Central

    Soerjomataram, Isabelle; Møller, Bjørn; Bray, Freddie; Ferlay, Jacques

    2016-01-01

    Abstract Objective To assess the validity of the GLOBOCAN methods for deriving national estimates of cancer incidence. Methods We obtained incidence and mortality data from Norway by region, year of diagnosis, cancer site, sex and 5-year age group for the period 1983–2012 from the NORDCAN database. Estimates for the year 2010 were derived using nine different methods from GLOBOCAN. These included the projection of national historical rates, the use of regional proxies and the combination of national mortality data with mortality to incidence ratios or relative survival proportions. We then compared the national estimates with recorded cancer incidence data. Findings Differences between the estimates derived using different methods varied by cancer site and sex. Methods based on projections performed better where major changes in recent trends were absent. Methods based on mortality data performed less well for cancers associated with small numbers of deaths and for cancers detectable by screening. In countries with longstanding cancer registries of high quality, regional-based, or trends-based incidence estimates perform reasonably well in comparison with recorded incidence. Conclusion Although the performance of the GLOBOCAN methods varies by cancer site and sex in this study, the results emphasize a need for more high-quality population-based cancer registries – either regional or, where practical and feasible, national registries – to describe cancer patterns and trends for planning cancer control priorities. PMID:26966328

  15. Dental age estimation in Brazilian HIV children using Willems' method.

    PubMed

    de Souza, Rafael Boschetti; da Silva Assunção, Luciana Reichert; Franco, Ademir; Zaroni, Fábio Marzullo; Holderbaum, Rejane Maria; Fernandes, Ângela

    2015-12-01

    The notification of the Human Immunodeficiency Virus (HIV) in Brazilian children was first reported in 1984. Since that time more than 21 thousand children became infected. Approximately 99.6% of the children aged less than 13 years old are vertically infected. In this context, most of the children are abandoned after birth, or lose their relatives in a near future, growing with uncertain identification. The present study aims to estimate the dental age of Brazilian HIV patients in face of healthy patients paired by age and gender. The sample consisted of 160 panoramic radiographs of male (n: 80) and female (n: 80) patients aged between 4 and 15 years (mean age: 8.88 years), divided into HIV (n: 80) and control (n: 80) groups. The sample was analyzed by three trained examiners, using Willems' method, 2001. Intraclass Correlation Coefficient (ICC) was applied to test intra- and inter-examiner agreement, and Student paired t-test was used to determine the age association between HIV and control groups. Intra-examiner (ICC: from 0.993 to 0.997) and inter-examiner (ICC: from 0.991 to 0.995) agreement tests indicated high reproducibility of the method between the examiners (P<0.01). Willems' method revealed discrete statistical overestimation in HIV (2.86 months; P=0.019) and control (1.90 months; P=0.039) groups. However, stratified analysis by gender indicate that overestimation were only concentrated in male HIV (3.85 months; P=0.001) and control (2.86 months; P=0.022) patients. The significant statistical differences are not clinically relevant once only few months of discrepancy are detected applying Willems' method in a Brazilian HIV sample, making this method highly recommended for dental age estimation of both HIV and healthy children with unknown age.

  16. Age estimation of bloodstains using smartphones and digital image analysis.

    PubMed

    Thanakiatkrai, Phuvadol; Yaodam, Alisa; Kitpipit, Thitika

    2013-12-10

    Recent studies on bloodstains have focused on determining the time since deposition of bloodstains, which can provide useful temporal information to forensic investigations. This study is the first to use smartphone cameras in combination with a truly low-cost illumination system as a tool to estimate the age of bloodstains. Bloodstains were deposited on various substrates and photographed with a smartphone camera. Three smartphones (Samsung Galaxy S Plus, Apple iPhone 4, and Apple iPad 2) were compared. The environmental effects - temperature, humidity, light exposure, and anticoagulant - on the bloodstain age estimation process were explored. The color values from the digital images were extracted and correlated with time since deposition. Magenta had the highest correlation (R(2)=0.966) and was used in subsequent experiments. The Samsung Galaxy S Plus was the most suitable smartphone as its magenta decreased exponentially with increasing time and had highest repeatability (low variation within and between pictures). The quantifiable color change observed is consistent with well-established hemoglobin denaturation process. Using a statistical classification technique called Random Forests™, we could predict bloodstain age accurately up to 42 days with an error rate of 12%. Additionally, the age of forty blind stains were all correctly predicted, and 83% of mock casework samples were correctly classified. No within- and between-person variations were observed (p>0.05), while smartphone camera, temperature, humidity, and substrate color influenced the age determination process in different ways. Our technique provides a cheap, rapid, easy-to-use, and truly portable alternative to more complicated analysis using specialized equipment, e.g. spectroscopy and HPLC. No training is necessary with our method, and we envision a smartphone application that could take user inputs of environmental factors and provide an accurate estimate of bloodstain age. PMID:24314532

  17. Estimating the Age Distribution of Oceanic Dissolved Organic Carbon

    NASA Astrophysics Data System (ADS)

    Follett, C. L.; Forney, D. C.; Repeta, D.; Rothman, D.

    2010-12-01

    Dissolved organic carbon (DOC) is a large, ubiquitous component of open ocean water at all depths and impacts atmospheric carbon dioxide levels at both short and long timescales. It is currently believed that oceanic DOC contains a multi-thousand-year-old refractory deep-water component which is mixed with a young labile component in surface waters. Unfortunately, the only evidence for this comes from a few isolated depth profiles of both DOC concentration and bulk radiocarbon. Although the profile data is consistent with a two-component mixing model, directly separating the two components has proven to be a challenge. We explore the validity of the two component mixing model by directly estimating the age distribution of oceanic DOC. The two-component model suggests that the age distribution is composed of two distinct peaks. In order to obtain an estimate of the age distribution we first record changes in both concentration and percent radiocarbon as a sample is oxidized under ultra-violet radiation [1]. We formulate a mathematical model relating the age distribution to these changes, assuming that they result from components of different radiocarbon age and UV-reactivity. This allows us to numerically invert the data and estimate the age distribution. We apply our procedure to DOC samples collected from three distinct depths (50, 500, and 2000 meters) in the north-central Pacific Ocean. [1] S.R. Beaupre, E.R.M. Druffel, and S. Griffin. A low-blank photochemical extraction system for concentration and isotopic analyses of marine dissolved organic carbon. Limnol. Oceanogr. Methods, 5:174-184, 2007.

  18. Human Age Estimation Based on Locality and Ordinal Information.

    PubMed

    Li, Changsheng; Liu, Qingshan; Dong, Weishan; Zhu, Xiaobin; Liu, Jing; Lu, Hanqing

    2015-11-01

    In this paper, we propose a novel feature selection-based method for facial age estimation. The face aging is a typical temporal process, and facial images should have certain ordinal patterns in the aging feature space. From the geometrical perspective, a facial image can be usually seen as sampled from a low-dimensional manifold embedded in the original high-dimensional feature space. Thus, we first measure the energy of each feature in preserving the underlying local structure information and the ordinal information of the facial images, respectively, and then we intend to learn a low-dimensional aging representation that can maximally preserve both kinds of information. To further improve the performance, we try to eliminate the redundant local information and ordinal information as much as possible by minimizing nonlinear correlation and rank correlation among features. Finally, we formulate all these issues into a unified optimization problem, which is similar to linear discriminant analysis in format. Since it is expensive to collect the labeled facial aging images in practice, we extend the proposed supervised method to a semi-supervised learning mode including the semi-supervised feature selection method and the semi-supervised age prediction algorithm. Extensive experiments are conducted on the FACES dataset, the Images of Groups dataset, and the FG-NET aging dataset to show the power of the proposed algorithms, compared to the state-of-the-arts. PMID:26470062

  19. Precision of hard structures used to estimate age of mountain Whitefish (Prosopium williamsoni)

    USGS Publications Warehouse

    Watkins, Carson J.; Ross, Tyler J.; Hardy, Ryan S.; Quist, Michael

    2015-01-01

    The mountain whitefish (Prosopium williamsoni) is a widely distributed salmonid in western North America that has decreased in abundance over portions of its distribution due to anthropogenic disturbances. In this investigation, we examined precision of age estimates derived from scales, pectoral fin rays, and sagittal otoliths from 167 mountain whitefish. Otoliths and pectoral fin rays were mounted in epoxy and cross-sectioned before examination. Scales were pressed onto acetate slides and resulting impressions were examined. Between-reader precision (i.e., between 2 readers), between-reader variability, and reader confidence ratings were compared among hard structures. Coefficient of variation (CV) in age estimates was lowest and percentage of exact agreement (PA-0) was highest for scales (CV = 5.9; PA-0 = 70%) compared to pectoral fin rays (CV =11.0; PA-0 = 58%) and otoliths (CV = 12.3; PA-0 = 55%). Median confidence ratings were significantly different (P ≤ 0.05) among all structures, with scales having the highest median confidence. Reader confidence decreased with fish age for scales and pectoral fin rays, but reader confidence increased with fish age for otoliths. In general, age estimates were more precise and reader confidence was higher for scales compared to pectoral fin rays and otoliths. This research will help fisheries biologists in selecting the most appropriate hard structure to use for future age and growth studies on mountain whitefish. In turn, selection of the most precise hard structure will lead to better estimates of dynamic rate functions.

  20. Estimating age from the pubic symphysis: A new component-based system.

    PubMed

    Dudzik, Beatrix; Langley, Natalie R

    2015-12-01

    The os pubis is one of the most widely used areas of the skeleton for age estimation. Current pubic symphyseal aging methods for adults combine the morphology associated with the developmental changes that occur into the mid-30s with the degenerative changes that span the latter portion of the age spectrum. The most popular methods are phase-based; however, the definitions currently used to estimate age intervals may not be adequately defined and/or accurately understood by burgeoning researchers and seasoned practitioners alike. This study identifies patterns of growth and maturation in the pubic symphysis to derive more precise age estimates for individuals under 40 years of age. Emphasis is placed on young adults to provide more informative descriptions of epiphyseal changes associated with the final phases of skeletal maturation before degeneration commences. This study investigated macroscopic changes in forensically relevant modern U.S. samples of known age, sex, and ancestry from the Maricopa County Forensic Science Center in Phoenix, Arizona as well as donated individuals from the William M. Bass Forensic and Donated Collections at the University of Tennessee, Knoxville (n=237). Age-related traits at locations with ontogenetic and biomechanical relevance were broken into components and scored. The components included the pubic tubercle, the superior apex of the face, the ventral and dorsal demifaces, and the ventral and dorsal symphyseal margins. Transition analysis was applied to elucidate the transition ages between the morphological states of each component. The categorical scores and transition analysis ages were subjected to multinomial logistic regression and decision tree analysis to derive accurate age interval estimates. Results of these analyses were used to construct a decision tree-style flow chart for practitioner use. High inter-rater agreement of the individual component traits (linear weighted kappa values ≥0.665 for all traits in the

  1. Application OF LIBS To Estimate The Age Of Broiler Breeders

    NASA Astrophysics Data System (ADS)

    Salam, Z. Abdel; Harith, M. A.

    2011-09-01

    Laser Induced Breakdown Spectroscopy (LIBS) is a well-known spectrochemical elemental analysis technique. In our investigations of the LIBS spectra it has been found that there is a remarkable correlation between the ionic to atomic spectral lines emission ratio and the surface hardness of eggshell for two Different Broiler Breeder at different age. The proposed technique has been applied successfully in poultry science to estimate the age of broiler breeders by measuring the surface hardness of their eggshell. The experiments have been performed on two different strains, Arbor Acres plus (AAP) and Hubard Classic (HC), and the results were satisfactory.

  2. Resistance reconstructed estimation of total peripheral resistance from computationally derived cardiac output - biomed 2013.

    PubMed

    Hill, Labarron K; Sollers Iii, John J; Thayer, Julian F

    2013-01-01

    Efficient functioning of the peripheral vasculature is an essential component in healthy cardiovascular regulation. Alterations in this functioning have been linked to the etiology and pathophysiological course of cardiovascular disease (CVD), especially hypertension. Given its significant role in the maintenance of both healthy and pathological blood pressure, total peripheral resistance (TPR), an index of the vasoconstrictive and elastic properties of the peripheral vasculature, has received much attention in this regard. However, obtaining a reliable estimate of TPR remains a complex and costly endeavor, primarily due to the necessity for sophisticated instrumentation as well as associated limitations in deriving cardiac output (CO). We have previously described a simple estimation method for CO using only arterial blood pressure and heart rate (Hill et al, 2012). In the present study we extend this technique to the estimation of TPR using beat-to-beat blood pressure data from the same sample of 67 young (mean age = 20.04± 2.8), healthy men (n = 30) and women (n = 37). Estimated TPR (TPRest) was calculated from the computationally-derived estimate of CO and mean arterial pressure (MAP). Correlation between TPR obtained via the validated Model-Flow technique and TPRest was moderate (r =.73, p <. 000) and stronger in men (r =.78, p <. 000) compared to women (r =.66, p <. 001). These data further suggest that reconstructed measures of hemodynamic functioning may be validly and adequately estimated from limited data sources.

  3. Human age estimation from blood using mRNA, DNA methylation, DNA rearrangement, and telomere length.

    PubMed

    Zubakov, Dmitry; Liu, Fan; Kokmeijer, Iris; Choi, Ying; van Meurs, Joyce B J; van IJcken, Wilfred F J; Uitterlinden, André G; Hofman, Albert; Broer, Linda; van Duijn, Cornelia M; Lewin, Jörn; Kayser, Manfred

    2016-09-01

    Establishing the age of unknown persons, or persons with unknown age, can provide important leads in police investigations, disaster victim identification, fraud cases, and in other legal affairs. Previous methods mostly relied on morphological features available from teeth or skeletal parts. The development of molecular methods for age estimation allowing to use human specimens that possess no morphological age information, such as bloodstains, is extremely valuable as this type of samples is commonly found at crime scenes. Recently, we introduced a DNA-based approach for human age estimation from blood based on the quantification of T-cell specific DNA rearrangements (sjTRECs), which achieves accurate assignment of blood DNA samples to one of four 20-year-interval age categories. Aiming at improving the accuracy of molecular age estimation from blood, we investigated different types of biomarkers. We started out by systematic genome-wide surveys for new age-informative mRNA and DNA methylation markers in blood from the same young and old individuals using microarray technologies. The obtained candidate markers were validated in independent samples covering a wide age range using alternative technologies together with previously proposed DNA methylation, sjTREC, and telomere length markers. Cross-validated multiple regression analysis was applied for estimating and validating the age predictive power of various sets of biomarkers within and across different marker types. We found that DNA methylation markers outperformed mRNA, sjTREC, and telomere length in age predictive power. The best performing model included 8 DNA methylation markers derived from 3 CpG islands reaching a high level of accuracy (cross-validated R(2)=0.88, SE±6.97 years, mean absolute deviation 5.07 years). However, our data also suggest that mRNA markers can provide independent age information: a model using a combined set of 5 DNA methylation markers and one mRNA marker could provide

  4. Human age estimation from blood using mRNA, DNA methylation, DNA rearrangement, and telomere length.

    PubMed

    Zubakov, Dmitry; Liu, Fan; Kokmeijer, Iris; Choi, Ying; van Meurs, Joyce B J; van IJcken, Wilfred F J; Uitterlinden, André G; Hofman, Albert; Broer, Linda; van Duijn, Cornelia M; Lewin, Jörn; Kayser, Manfred

    2016-09-01

    Establishing the age of unknown persons, or persons with unknown age, can provide important leads in police investigations, disaster victim identification, fraud cases, and in other legal affairs. Previous methods mostly relied on morphological features available from teeth or skeletal parts. The development of molecular methods for age estimation allowing to use human specimens that possess no morphological age information, such as bloodstains, is extremely valuable as this type of samples is commonly found at crime scenes. Recently, we introduced a DNA-based approach for human age estimation from blood based on the quantification of T-cell specific DNA rearrangements (sjTRECs), which achieves accurate assignment of blood DNA samples to one of four 20-year-interval age categories. Aiming at improving the accuracy of molecular age estimation from blood, we investigated different types of biomarkers. We started out by systematic genome-wide surveys for new age-informative mRNA and DNA methylation markers in blood from the same young and old individuals using microarray technologies. The obtained candidate markers were validated in independent samples covering a wide age range using alternative technologies together with previously proposed DNA methylation, sjTREC, and telomere length markers. Cross-validated multiple regression analysis was applied for estimating and validating the age predictive power of various sets of biomarkers within and across different marker types. We found that DNA methylation markers outperformed mRNA, sjTREC, and telomere length in age predictive power. The best performing model included 8 DNA methylation markers derived from 3 CpG islands reaching a high level of accuracy (cross-validated R(2)=0.88, SE±6.97 years, mean absolute deviation 5.07 years). However, our data also suggest that mRNA markers can provide independent age information: a model using a combined set of 5 DNA methylation markers and one mRNA marker could provide

  5. A review of the most commonly used dental age estimation techniques.

    PubMed

    Willems, G

    2001-06-01

    This review of literature provides an overview of the most commonly used dental age estimation techniques and focuses on dental age estimation scoring systems in children and adults. In order to obtain a more reliable and reproducible age estimation the forensic odontologist should use several of these available methods whenever an age estimation in the living or dead is required. PMID:11494678

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

    PubMed Central

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

    2015-01-01

    Aim: 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. Materials and Methods: 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). Results: 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, R2 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. Conclusion: 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. PMID:26005306

  7. Age estimation among Brazilians: Younger or older than 18?

    PubMed

    Deitos, Alexandre Raphael; Costa, Claudio; Michel-Crosato, Edgard; Galić, Ivan; Cameriere, Roberto; Biazevic, Maria Gabriela Haye

    2015-07-01

    The age estimation of living or dead individuals is an important part of forensic science because it can be used in various situations, including mass disasters, or for civil or criminal reasons, such as adoption or asylum. Teeth play a major role in this context because they are more resistant than bones in extreme environmental conditions and their development is hardly affected by exogenous or endogenous factors. Because the third molars (3rdM) are still in development from the age of 14, they are useful for determining whether an individual has reached the legal age of 18 years. This study aims to verify the method of Cameriere et al. (2008) in Brazil to discriminate whether an individual is under or over 18 years from the maturity index of the 3rdM (I3m). The analysis of 444 panoramic radiographs resulted in a sensitivity of 78.3%, a specificity of 85.1% and a correct classification of 87%. Significant differences in sexual dimorphism in the early mineralization of males were found only for the average age with I3m ≥ 0.08, except for the range (0.7, 0.9). Due to the high miscegenation ratio of the Brazilian population the ancestry was not one of the studied variables. The method is suitable for estimating adulthood for forensic purposes in Brazil, although it must be applied carefully and judiciously. We recommend a combination of several methods that are available to increase accuracy as well as the establishment of different parameters that are likely to determine whether a person is more or less than 18 years of age, depending on the different legal requirements, whether civil or criminal.

  8. Comparative study of age estimation using dentinal translucency by digital and conventional methods

    PubMed Central

    Bommannavar, Sushma; Kulkarni, Meena

    2015-01-01

    Introduction: Estimating age using the dentition plays a significant role in identification of the individual in forensic cases. Teeth are one of the most durable and strongest structures in the human body. The morphology and arrangement of teeth vary from person-to-person and is unique to an individual as are the fingerprints. Therefore, the use of dentition is the method of choice in the identification of the unknown. Root dentin translucency is considered to be one of the best parameters for dental age estimation. Traditionally, root dentin translucency was measured using calipers. Recently, the use of custom built software programs have been proposed for the same. Objectives: The present study describes a method to measure root dentin translucency on sectioned teeth using a custom built software program Adobe Photoshop 7.0 version (Adobe system Inc, Mountain View California). Materials and Methods: A total of 50 single rooted teeth were sectioned longitudinally to derive a 0.25 mm uniform thickness and the root dentin translucency was measured using digital and caliper methods and compared. The Gustafson's morphohistologic approach is used in this study. Results: Correlation coefficients of translucency measurements to age were statistically significant for both the methods (P < 0.125) and linear regression equations derived from both methods revealed better ability of the digital method to assess age. Conclusion: The custom built software program used in the present study is commercially available and widely used image editing software. Furthermore, this method is easy to use and less time consuming. The measurements obtained using this method are more precise and thus help in more accurate age estimation. Considering these benefits, the present study recommends the use of digital method to assess translucency for age estimation. PMID:25709325

  9. Bombardment History of the Galilean Satellites and Derived Ages

    NASA Astrophysics Data System (ADS)

    Neukum, G.; Wagner, R.; Wolf, U.; Head, J. W., III; Pappalardo, R.; Chapman, C. R.; Merline, W.; Belton, M. S.

    1997-07-01

    During the first seven Galileo flybys, high resolution imagery of the three Galilean moons, Europa, Ganymede and Callisto have been obtained. The new imaging data allow to measure crater diameters as small as ~ 100 m. In combination with Voyager data, size-frequency distribution characteristics in the size range of ~ 100 m to ~ 100 km have been determined. Crater distributions show steep slopes (cumulative index about -3) at smaller diameters on each satellite and are shallower at larger diameters, similar to what is seen on the Moon and the asteroids Gaspra and Ida. % % At D = 1 km, crater densities differ by about a factor of 10 between % average dark terrain of Galileo Regio and youngest bright resurfaced areas % on Ganymede. % Crater densities on the most heavily cratered regions on both Ganymede and Callisto are fairly comparable. On Europa, crater densities have turned out to be about a factor of 10 lower than on the youngest bright terrain in the Uruk Sulcus region of Ganymede. The similarity to crater size-frequency distributions found in the inner solar system suggests a similar origin of the projectiles, probably mainly stemming from the asteroid belt, and the impact rate on the Galilean satellites may have had a lunar-like decay with time. Under this assumption, absolute ages may be derived making use of the idea of the ''marker horizon'', i. e. formation of the youngest basins, such as Gilgamesh on Ganymede, about 3.8 b.y. ago. Thus, the most densely cratered dark terrains on both Ganymede and Callisto have likely ages of 4.1 - 4.3 b.y. Basins such as Neith (on Ganymede) or Adlinda (on Callisto) yield likely ages of about 3.9 b.y. Some areas on Europa may be as old as 3 - 3.3 b.y. Other scenarios based on values proposed for the present-day comet impact rate in the Jovian system with non-lunar-like flux time dependences are conceivable and would result in generally younger ages, possibly as young as 10 m.y. These young ages and impact rates for Europa

  10. Estimating the age of alleles by use of intraallelic variability

    SciTech Connect

    Slatkin, M.; Rannala, B.

    1997-02-01

    A method is presented for estimating the age of an allele by use of its frequency and the extent of variation among different copies. The method uses the joint distribution of the number of copies in a population sample and the coalescence times of the intraallelic gene genealogy conditioned on the number of copies. The linear birth-death process is used to approximate the dynamics of a rare allele in a finite population. A maximum-likelihood estimate of the age of the allele is obtained by Monte Carlo integration over the coalescence times. The method is applied to two alleles at the cystic fibrosis (CFTR) locus, {Delta}F508 and G542X, for which intraallelic variability at three intronic microsatellite loci has been examined. Our results indicate that G542X is somewhat older than {Delta}F508. Although absolute estimates depend on the mutation rates at the microsatellite loci, our results support the hypothesis that {Delta}F508 arose <500 generations ({approx}10,000 years) ago. 32 refs., 4 figs.

  11. Age estimation in Indian children and adolescents in the NCR region of Haryana: A comparative study

    PubMed Central

    Gupta, Swati; Mehendiratta, Monica; Rehani, Shweta; Kumra, Madhumani; Nagpal, Ruchi; Gupta, Ramakant

    2015-01-01

    Introduction: Age estimation is a preliminary step in the identification of an individual. It is a crucial and often most critical step for forensic experts. The assessment has been standardized utilizing common dental diagnostic x-rays, but most such age-estimating systems are European population-based and their applicability has not been determined in the context of the Indian population. Aims and Objectives: To assess the applicability and to compare the methods of dental age estimation by Demirjian's method and the same method as modified by Willems (i.e. the Willems method) in Indian children of the National Capital Region (NCR). Also, to find a correlation among skeletal maturity using the Cervical vertebrae maturation index (CVMI), dental maturity, and chronological age in the same population. Materials and Methods: This cross-sectional study was conducted using dental radiographs of 70 orthodontic patients (37 males, 33 females) in the age range 9-16 years selected by simple random sampling. pantomogram were used to estimate dental age by Demirjian's method and the Willems method using their scoring tables. Lateral cephalograms were used to estimate skeletal maturity using CVMI. The latter was compared with Demirjian's stage for mandibular left second molar. Results: Overestimation of age among males by 0.856 years and 0.496 years was found by Demirjian's and the Willems methods, respectively. Among females, both the methods underestimated the age by 0.31 years and 0.45 years, respectively. Demirjian's stage G corresponded to CVMI stage 3 in males and stage 2 in females. Conclusion: In our study, the Willems method has proved to be more accurate for age estimation among Indian males, and Demirjian's method for Indian females. A statistically significant association appeared between Demirjian's stages and CVMI among both males and females. Our study recommends the derivation of a regression formula by studying a larger section of the Indian population

  12. A New Approach to Estimate the Age of the Earth and the Age of the Universe

    NASA Astrophysics Data System (ADS)

    Ben Salem, Kamel

    2011-01-01

    In a previous article, we proposed estimations for the age of the Universe and for the date of stabilization of its general structure on the basis of a given age of the Earth equal to 4.6 billion years. In the present article, we propose a new approach to estimate more accurately and at the same time, the age of the Earth and that of the Universe, starting from verse 4 of Sura 70 of the Qur'an. The procedure we followed and which is detailed in this article, should in our view, contribute to enlighten the debate on the question. We must add that our approach can in no case be considered as based on "concordism" or conjecture. Indeed, it rests on rigorous mathematical computations.

  13. Human age estimation combining third molar and skeletal development.

    PubMed

    Thevissen, P W; Kaur, J; Willems, G

    2012-03-01

    The wide prediction intervals obtained with age estimation methods based on third molar development could be reduced by combining these dental observations with age-related skeletal information. Therefore, on cephalometric radiographs, the most accurate age-estimating skeletal variable and related registration method were searched and added to a regression model, with age as response and third molar stages as explanatory variable. In a pilot set up on a dataset of 496 (283 M; 213 F) cephalometric radiographs, the techniques of Baccetti et al. (2005) (BA), Seedat et al. (2005) (SE), Caldas et al. (2007) and Rai et al. (2008) (RA) were verified. In the main study, data from 460 (208 F, 224 M) individuals in an age range between 3 and 26 years, for which at the same day an orthopantogram and a cephalogram were taken, were collected. On the orthopantomograms, the left third molar development was registered using the scoring system described by Gleiser and Hunt (1955) and modified by Köhler (1994) (GH). On the cephalograms, cervical vertebrae development was registered according to the BA and SE techniques. A regression model, with age as response and the GH scores as explanatory variable, was fitted to the data. Next, information of BA, SE and BA + SE was, respectively, added to this model. From all obtained models, the determination coefficients and the root mean squared errors were calculated. Inclusion of information from cephalograms based on the BA, as well as the SE, technique improved the amount of explained variance in age acquired from panoramic radiographs using the GH technique with 48%. Inclusion of cephalometric BA + SE information marginally improved the previous result (+1%). The RMSE decreased with 1.93, 1.85 and 2.03 years by adding, respectively, BA, SE and BA + SE information to the GH model. The SE technique allows clinically the fastest and easiest registration of the degree of development of the cervical vertebrae. Therefore, the choice of

  14. Estimation of fetal gestational age from ultrasound images

    NASA Astrophysics Data System (ADS)

    Salari, Valiollah

    1992-06-01

    Estimation of fetal gestational age, weight, and determination of fetal growth from the measurements of certain parameters of fetal head, abdomen, and femur have been well established in prenatal sonography. The measurements are made from the two dimensional, B- mode, ultrasound images of the fetus. The most common parameters measured are, biparietal diameter, occipital frontal diameter, head circumference, femur diaphysis length, and abdominal circumference. Since the fetal head has an elliptical shape and the femur has a linear shape, fitting the ellipse on the image of the fetal head, a line on the image of the femur are the tasks of image processing which are discussed in this paper.

  15. Human dental age estimation combining third molar(s) development and tooth morphological age predictors.

    PubMed

    Thevissen, P W; Galiti, D; Willems, G

    2012-11-01

    In the subadult age group, third molar development, as well as age-related morphological tooth information can be observed on panoramic radiographs. The aim of present study was to combine, in subadults, panoramic radiographic data based on developmental stages of third molar(s) and morphological measurements from permanent teeth, in order to evaluate its added age-predicting performances. In the age range between 15 and 23 years, 25 gender-specific radiographs were collected within each age category of 1 year. Third molar development was classified and registered according the 10-point staging and scoring technique proposed by Gleiser and Hunt (1955), modified by Köhler (1994). The Kvaal (1995) measuring technique was applied on the indicated teeth from the individuals' left side. Linear regression models with age as response and third molar-scored stages as explanatory variables were developed, and morphological measurements from permanent teeth were added. From the models, determination coefficients (R (2)) and root-mean-square errors (RMSE) were calculated. Maximal-added age information was reported as a 6 % R² increase and a 0.10-year decrease of RMSE. Forensic dental age estimations on panoramic radiographic data in the subadult group (15-23 year) should only be based on third molar development.

  16. Red giant masses and ages derived from carbon and nitrogen abundances

    NASA Astrophysics Data System (ADS)

    Martig, Marie; Fouesneau, Morgan; Rix, Hans-Walter; Ness, Melissa; Mészáros, Szabolcs; García-Hernández, D. A.; Pinsonneault, Marc; Serenelli, Aldo; Silva Aguirre, Victor; Zamora, Olga

    2016-03-01

    We show that the masses of red giant stars can be well predicted from their photospheric carbon and nitrogen abundances, in conjunction with their spectroscopic stellar labels log g, Teff, and [Fe/H]. This is qualitatively expected from mass-dependent post-main-sequence evolution. We here establish an empirical relation between these quantities by drawing on 1475 red giants with asteroseismic mass estimates from Kepler that also have spectroscopic labels from Apache Point Observatory Galactic Evolution Experiment (APOGEE) DR12. We assess the accuracy of our model, and find that it predicts stellar masses with fractional rms errors of about 14 per cent (typically 0.2 M⊙). From these masses, we derive ages with rms errors of 40 per cent. This empirical model allows us for the first time to make age determinations (in the range 1-13 Gyr) for vast numbers of giant stars across the Galaxy. We apply our model to ˜52 000 stars in APOGEE DR12, for which no direct mass and age information was previously available. We find that these estimates highlight the vertical age structure of the Milky Way disc, and that the relation of age with [α/M] and metallicity is broadly consistent with established expectations based on detailed studies of the solar neighbourhood.

  17. Age estimation using pulp/tooth area ratio in maxillary canines-A digital image analysis

    PubMed Central

    Juneja, Manjushree; Devi, Yashoda B. K.; Rakesh, N.; Juneja, Saurabh

    2014-01-01

    Introduction: Determination of age of a subject is one of the most important aspects of medico-legal cases and anthropological research. Radiographs can be used to indirectly measure the rate of secondary dentine deposition which is depicted by reduction in the pulp area. Materials and Methods: In this study, 200 patients of Karnataka aged between 18-72 years were selected for the study. Panoramic radiographs were made and indirectly digitized. Radiographic images of maxillary canines (RIC) were processed using a computer-aided drafting program (ImageJ). The variables pulp/root length (p), pulp/tooth length (r), pulp/root width at enamel-cementum junction (ECJ) level (a), pulp/root width at mid-root level (c), pulp/root width at midpoint level between ECJ level and mid-root level (b) and pulp/tooth area ratio (AR) were recorded. All the morphological variables including gender were statistically analyzed to derive regression equation for estimation of age. Results: It was observed that 2 variables ‘AR’ and ‘b’ contributed significantly to the fit and were included in the regression model, yielding the formula: Age = 87.305−480.455(AR)+48.108(b). Statistical analysis indicated that the regression equation with selected variables explained 96% of total variance with the median of the residuals of 0.1614 years and standard error of estimate of 3.0186 years. Conclusion: There is significant correlation between age and morphological variables ‘AR’ and ‘b’ and the derived population specific regression equation can be potentially used for estimation of chronological age of individuals of Karnataka origin. PMID:25177137

  18. Aging Effects on Behavioural Estimates of Suppression with Short Suppressors.

    PubMed

    Hegland, Erica L; Strickland, Elizabeth A

    2016-01-01

    Auditory two-tone suppression is a nearly instantaneous reduction in the response of the basilar membrane to a tone or noise when a second tone or noise is presented simultaneously. Previous behavioural studies provide conflicting evidence on whether suppression changes with increasing age, and aging effects may depend on whether a suppressor above (high-side) or below (low-side) the signal frequency is used. Most previous studies have measured suppression using stimuli long enough to elicit the medial olivocochlear reflex (MOCR), a sound-elicited reflex that reduces cochlear amplification or gain. It has a "sluggish" onset of approximately 25 ms. There is physiological evidence that suppression may be reduced or altered by elicitation of the MOCR. In the present study, suppression was measured behaviourally in younger adults and older adults using a forward-masking paradigm with 20-ms and 70-ms maskers and suppressors. In experiment 1, gain was estimated by comparing on-frequency (2 kHz) and off-frequency (1.2 kHz) masker thresholds for a short, fixed-level 2-kHz signal. In experiment 2, the fixed-level signal was preceded by an off-frequency suppressor (1.2 or 2.4 kHz) presented simultaneously with the on-frequency masker. A suppressor level was chosen that did not produce any forward masking of the signal. Suppression was measured as the difference in on-frequency masker threshold with and without the suppressor present. The effects of age on gain and suppression estimates will be discussed.

  19. Optimal dental age estimation practice in United Arab Emirates' children.

    PubMed

    Altalie, Salem; Thevissen, Patrick; Fieuws, Steffen; Willems, Guy

    2014-03-01

    The aim of the study was to detect whether the Willems model, developed on a Belgian reference sample, can be used for age estimations in United Arab Emirates (UAE) children. Furthermore, it was verified that if added third molars development information in children provided more accurate age predictions. On 1900 panoramic radiographs, the development of left mandibular permanent teeth (PT) and third molars (TM) was registered according the Demirjian and the Kohler technique, respectively. The PT data were used to verify the Willems model and to develop a UAE model and to verify it. Multiple regression models with PT, TM, and PT + TM scores as independent and age as dependent factor were developed. Comparing the verified Willems- and the UAE model revealed differences in mean error of -0.01 year, mean absolute error of 0.01 year and root mean squared error of 0.90 year. Neglectable overall decrease in RMSE was detected combining PM and TM developmental information. PMID:24261921

  20. Optimal dental age estimation practice in United Arab Emirates' children.

    PubMed

    Altalie, Salem; Thevissen, Patrick; Fieuws, Steffen; Willems, Guy

    2014-03-01

    The aim of the study was to detect whether the Willems model, developed on a Belgian reference sample, can be used for age estimations in United Arab Emirates (UAE) children. Furthermore, it was verified that if added third molars development information in children provided more accurate age predictions. On 1900 panoramic radiographs, the development of left mandibular permanent teeth (PT) and third molars (TM) was registered according the Demirjian and the Kohler technique, respectively. The PT data were used to verify the Willems model and to develop a UAE model and to verify it. Multiple regression models with PT, TM, and PT + TM scores as independent and age as dependent factor were developed. Comparing the verified Willems- and the UAE model revealed differences in mean error of -0.01 year, mean absolute error of 0.01 year and root mean squared error of 0.90 year. Neglectable overall decrease in RMSE was detected combining PM and TM developmental information.

  1. Estimation of submarine mass failure probability from a sequence of deposits with age dates

    USGS Publications Warehouse

    Geist, Eric L.; Chaytor, Jason D.; Parsons, Thomas E.; ten Brink, Uri S.

    2013-01-01

    The empirical probability of submarine mass failure is quantified from a sequence of dated mass-transport deposits. Several different techniques are described to estimate the parameters for a suite of candidate probability models. The techniques, previously developed for analyzing paleoseismic data, include maximum likelihood and Type II (Bayesian) maximum likelihood methods derived from renewal process theory and Monte Carlo methods. The estimated mean return time from these methods, unlike estimates from a simple arithmetic mean of the center age dates and standard likelihood methods, includes the effects of age-dating uncertainty and of open time intervals before the first and after the last event. The likelihood techniques are evaluated using Akaike’s Information Criterion (AIC) and Akaike’s Bayesian Information Criterion (ABIC) to select the optimal model. The techniques are applied to mass transport deposits recorded in two Integrated Ocean Drilling Program (IODP) drill sites located in the Ursa Basin, northern Gulf of Mexico. Dates of the deposits were constrained by regional bio- and magnetostratigraphy from a previous study. Results of the analysis indicate that submarine mass failures in this location occur primarily according to a Poisson process in which failures are independent and return times follow an exponential distribution. However, some of the model results suggest that submarine mass failures may occur quasiperiodically at one of the sites (U1324). The suite of techniques described in this study provides quantitative probability estimates of submarine mass failure occurrence, for any number of deposits and age uncertainty distributions.

  2. Lake Erie Yellow perch age estimation based on three structures: Precision, processing times, and management implications

    USGS Publications Warehouse

    Vandergoot, C.S.; Bur, M.T.; Powell, K.A.

    2008-01-01

    Yellow perch Perca flavescens support economically important recreational and commercial fisheries in Lake Erie and are intensively managed. Age estimation represents an integral component in the management of Lake Erie yellow perch stocks, as age-structured population models are used to set safe harvest levels on an annual basis. We compared the precision associated with yellow perch (N = 251) age estimates from scales, sagittal otoliths, and anal spine sections and evaluated the time required to process and estimate age from each structure. Three readers of varying experience estimated ages. The precision (mean coefficient of variation) of estimates among readers was 1% for sagittal otoliths, 5-6% for anal spines, and 11-13% for scales. Agreement rates among readers were 94-95% for otoliths, 71-76% for anal spines, and 45-50% for scales. Systematic age estimation differences were evident among scale and anal spine readers; less-experienced readers tended to underestimate ages of yellow perch older than age 4 relative to estimates made by an experienced reader. Mean scale age tended to underestimate ages of age-6 and older fish relative to otolith ages estimated by an experienced reader. Total annual mortality estimates based on scale ages were 20% higher than those based on otolith ages; mortality estimates based on anal spine ages were 4% higher than those based on otolith ages. Otoliths required more removal and preparation time than scales and anal spines, but age estimation time was substantially lower for otoliths than for the other two structures. We suggest the use of otoliths or anal spines for age estimation in yellow perch (regardless of length) from Lake Erie and other systems where precise age estimates are necessary, because age estimation errors resulting from the use of scales could generate incorrect management decisions. ?? Copyright by the American Fisheries Society 2008.

  3. Postnatal growth and age estimation in Scotophilus kuhlii.

    PubMed

    Chen, Shiang-Fan; Huang, Shang-Shang; Lu, Dau-Jye; Shen, Tsung-Jen

    2016-01-01

    Adequate postnatal growth is important for young bats to develop skilled sensory and locomotor abilities, which are highly associated with their survival once independent. This study investigated the postnatal growth and development of Scotophilus kuhlii in captivity. An empirical growth curve was established, and the postnatal growth rate was quantified to derive an age-predictive equation. By further controlling the fostering conditions of twins, the differences in the development patterns between pups that received maternal care or were hand-reared were analyzed to determine whether the latter developed in the same manner as their maternally reared counterparts. Our results indicate that both forearm length and body mass increased rapidly and linearly during the first 4 weeks, after which the growth rate gradually decreased to reach a stable level. The first flight occurred at an average age of 39 days with a mean forearm length and body mass of 92.07% and 70.52% of maternal size, respectively. The developmental pattern of hand-reared pups, although similar to that of their maternally reared twin siblings, displayed a slightly faster growth rate in the 4th and 5th weeks. The heavier body mass of hand-reared pups during the pre-fledging period may cause higher wing loading, potentially influencing the flight performance and survival of the bats once independent. PMID:26600428

  4. The Impact of Starspots on Mass and Age Estimates for Pre-main Sequence Stars

    NASA Astrophysics Data System (ADS)

    Somers, Garrett; Pinsonneault, Marc H.

    2016-01-01

    We investigate the impact of starspots on the evolution of late-type stars during the pre-main sequence (pre-MS). We find that heavy spot coverage increases the radii of stars by 4-10%, consistent with inflation factors in eclipsing binary systems, and suppresses the rate of pre-MS lithium depletion, leading to a dispersion in zero-age MS Li abundance (comparable to observed spreads) if a range of spot properties exist within clusters from 3-10 Myr. This concordance with data implies that spots induce a range of radii at fixed mass during the pre-MS. These spots decrease the luminosity and T eff of stars, leading to a displacement on the HR diagram. This displacement causes isochrone derived masses and ages to be systematically under-estimated, and can lead to the spurious appearance of an age spread in a co-eval population.

  5. LiDAR-derived carbon estimates in encroaching juniper woodlands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Woody encroachment is thought to contribute significantly to the global carbon (C) sink. The global- and continental-scale estimates of this contribution, however, have large uncertainties. The woody encroachment contribution to the C sink needs to be estimated at regional and local scales to addres...

  6. Mean thermospheric density estimation derived from satellite constellations

    NASA Astrophysics Data System (ADS)

    Li, Alan; Close, Sigrid

    2015-10-01

    This paper defines a method to estimate the mean neutral density of the thermosphere given many satellites of the same form factor travelling in similar regions of space. A priori information to the estimation scheme include ranging measurements and a general knowledge of the onboard ADACS, although precise measurements are not required for the latter. The estimation procedure seeks to utilize order statistics to estimate the probability of the minimum drag coefficient achievable, and amalgamating all measurements across multiple time periods allows estimation of the probability density of the ballistic factor itself. The model does not depend on prior models of the atmosphere; instead we require estimation of the minimum achievable drag coefficient which is based upon physics models of simple shapes in free molecular flow. From the statistics of the minimum, error statistics on the estimated atmospheric density can be calculated. Barring measurement errors from the ranging procedure itself, it is shown that with a constellation of 10 satellites, we can achieve a standard deviation of roughly 4% on the estimated mean neutral density. As more satellites are added to the constellation, the result converges towards the lower limit of the achievable drag coefficient, and accuracy becomes limited by the quality of the ranging measurements and the probability of the accommodation coefficient. Comparisons are made to existing atmospheric models such as NRLMSISE-00 and JB2006.

  7. Radii, masses, and ages of 18 bright stars using interferometry and new estimations of exoplanetary parameters

    NASA Astrophysics Data System (ADS)

    Ligi, R.; Creevey, O.; Mourard, D.; Crida, A.; Lagrange, A.-M.; Nardetto, N.; Perraut, K.; Schultheis, M.; Tallon-Bosc, I.; ten Brummelaar, T.

    2016-02-01

    Context. Accurate stellar parameters are needed in numerous domains of astrophysics. The position of stars on the Hertzsprung-Russell diagram is an important indication of their structure and evolution, and it helps improve stellar models. Furthermore, the age and mass of stars hosting planets are required elements for studying exoplanetary systems. Aims: We aim at determining accurate parameters of a set of 18 bright exoplanet host and potential host stars from interferometric measurements, photometry, and stellar models. Methods: Using the VEGA/CHARA interferometer operating in the visible domain, we measured the angular diameters of 18 stars, ten of which host exoplanets. We combined them with their distances to estimate their radii. We used photometry to derive their bolometric flux and, then, their effective temperature and luminosity to place them on the H-R diagram. We then used the PARSEC models to derive their best fit ages and masses, with error bars derived from Monte Carlo calculations. Results: Our interferometric measurements lead to an average of 1.9% uncertainty on angular diameters and 3% on stellar radii. There is good agreement between measured and indirect estimations of angular diameters (either from SED fitting or from surface brightness relations) for main sequence (MS) stars, but not as good for more evolved stars. For each star, we provide a likelihood map in the mass-age plane; typically, two distinct sets of solutions appear (an old and a young age). The errors on the ages and masses that we provide account for the metallicity uncertainties, which are often neglected by other works. From measurements of its radius and density, we also provide the mass of 55 Cnc independently of models. From the stellar masses, we provide new estimates of semi-major axes and minimum masses of exoplanets with reliable uncertainties. We also derive the radius, density, and mass of 55 Cnc e, a super-Earth that transits its stellar host. Our exoplanetary

  8. Seasonal comparisons of sea ice concentration estimates derived from SSM/I, OKEAN and RADARSAT data

    USGS Publications Warehouse

    Belchansky, G.I.; Douglas, D.C.

    2002-01-01

    highly correlated during winter, spring, and fall, with mean differences of less than 8.1% (SD < 15%) for the NASA Team algorithm, and less than 2.8 % (SD < 13.8%) for the Bootstrap algorithm. Respective differences between SSM/I NASA Team and SSM/I Bootstrap total concentrations were less than 5.3% (SD < 6.9%). Monthly mean differences between SSM/I and OKEAN differed annually by less than 6%, with smaller differences primarily in winter. The NASA Team and Bootstrap algorithms underestimated the total sea ice concentrations relative to the RADARSAT ScanSAR no more than 3.0% (SD<9 %) and 1.2% (SD < 7.5%) during cold months, and no more than 12% and 7% during summer, respectively. ScanSAR tended to estimate higher ice concentrations for ice concentrations greater than 50%, when compared to SSM/I during all months. ScanSAR underestimated total sea ice concentration by 2 % compared to the OKEAN-01 algorithm during cold months, and gave an overestimation by 2% during spring and summer months. Total NASA Team and Bootstrap sea ice concentration estimates derived from coincident SSM/I and OKEAN-01 data demonstrated mean differences no more than 5.3 % (SD < 7%), 3.1 % (SD < 5.5%), 2.0% (SD < 5.5%), and 7.3 % (SD < 10%) for fall, winter, spring, and summer periods, respectively. Large disagreements were observed between the OKEAN and NASA Team results in spring and summer for estimates of the first-year and multiyear age classes. The OKEAN-01 algorithm and data tended to estimate, on average, lower concentrations of young or first-year ice and higher concentrations of total and multiyear ice for all months and seasons. Our results contribute to the growing body of documentation about the levels of disparity obtained when seasonal sea ice concentrations are estimated using various types of satellite data and algorithms.

  9. Relationships between net primary productivity and forest stand age derived from Forest Inventory and Analysis data and remote sensing imagery

    NASA Astrophysics Data System (ADS)

    He, L.; Chen, J. M.; Pan, Y.; Birdsey, R.

    2010-12-01

    Forest net primary productivity (NPP) varies greatly with stand age, and quantitative information on NPP-age relationship is therefore fundamentally important for forest carbon cycle modeling. We may use four terms to calculate NPP: annual accumulation of live biomass, annual mortality of aboveground and belowground biomass, foliage turnover to soil, and fine root turnover in soil. To derive NPP-age relationships for US forests, the Forest Inventory and Analysis (FIA) data are used to estimate the first two terms. The last two terms make up more than 50% of total NPP, but their estimates are highly uncertain based on limited available empirical relationships between aboveground biomass and foliage or fine root biomass. These estimates are mostly confounded by unknown variations of the turnover rates (TR) related to stand age because such field information is rare. To resolve this problem, we developed a new approach by using a leaf area index (LAI) map and a forest age map at 1 km resolution to derive LAI-age relationships for 18 major forest species groups in the USA. These relationships are then used to derive foliage TR using species-specific leaf longevity values. These relationships are also used for estimating the fine root TR based on reliable relationships between fine root and foliage TR. This combination of FIA and remote sensing data allows us for the first time to derive reliable NPP-age relationships for different forest types in USA (Figure 1). The derived relationships show a general temporal pattern of rapid increase in NPP in early ages, peak growth in mid-ages, and slow decline in old ages. The patterns are subjected to climate conditions, and can also be influenced by forest management. These relationships are further generalized for three major forest biomes for continental-scale carbon cycle modeling in conjunction with remotely sensed land cover types. The NPP relationships derived here may have many uses for analysis of management and climate

  10. A New Method for Deriving Global Estimates of Maternal Mortality.

    PubMed

    Wilmoth, John R; Mizoguchi, Nobuko; Oestergaard, Mikkel Z; Say, Lale; Mathers, Colin D; Zureick-Brown, Sarah; Inoue, Mie; Chou, Doris

    2012-07-13

    Maternal mortality is widely regarded as a key indicator of population health and of social and economic development. Its levels and trends are monitored closely by the United Nations and others, inspired in part by the UN's Millennium Development Goals (MDGs), which call for a three-fourths reduction in the maternal mortality ratio between 1990 and 2015. Unfortunately, the empirical basis for such monitoring remains quite weak, requiring the use of statistical models to obtain estimates for most countries. In this paper we describe a new method for estimating global levels and trends in maternal mortality. For countries lacking adequate data for direct calculation of estimates, we employed a parametric model that separates maternal deaths related to HIV/AIDS from all others. For maternal deaths unrelated to HIV/AIDS, the model consists of a hierarchical linear regression with three predictors and variable intercepts for both countries and regions. The uncertainty of estimates was assessed by simulating the estimation process, accounting for variability both in the data and in other model inputs. The method was used to obtain the most recent set of UN estimates, published in September 2010. Here, we provide a concise description and explanation of the approach, including a new analysis of the components of variability reflected in the uncertainty intervals. Final estimates provide evidence of a more rapid decline in the global maternal mortality ratio than suggested by previous work, including another study published in April 2010. We compare findings from the two recent studies and discuss topics for further research to help resolve differences. PMID:24416714

  11. Early-age concrete strength estimation based on piezoelectric sensor using artificial neural network

    NASA Astrophysics Data System (ADS)

    Kim, Junkyeong; Kim, Ju-Won; Park, Seunghee

    2014-04-01

    Recently, novel methods to estimate the strength of concrete have been reported based on numerous NDT methods. Especially, electro-mechanical impedance technique using piezoelectric sensors are studied to estimate the strength of concrete. However, the previous research works could not provide the general information about the early-age strength important to manage the quality of concrete and/or the construction process. In order to estimate the early-age strength of concrete, the electro-mechanical impedance method and the artificial neural network(ANN) is utilized in this study. The electro-mechanical impedance varies with the mechanical properties of host structures. Because the strength development is most influential factor among the change of mechanical properties at early-age of curing, it is possible to estimate the strength of concrete by analyzing the change of E/M impedance. The strength of concrete is a complex function of several factors like mix proportion, temperature, elasticity, etc. Because of this, it is hard to mathematically derive equations about strength of concrete. The ANN can provide the solution about early-age strength of concrete without mathematical equations. To verify the proposed approach, a series of experimental studies are conducted. The impedance signals are measured using embedded piezoelectric sensors during curing process and the resonant frequency of impedance is extracted as a strength feature. The strength of concrete is calculated by regression of strength development curve obtained by destructive test. Then ANN model is established by trained using experimental results. Finally the ANN model is verified using impedance data of other sensors.

  12. Reliability of India-specific regression formula for age estimation of population in and around Bahadurgarh, Haryana (India)

    PubMed Central

    Tandon, Ankita; Agarwal, Vartika; Arora, Varun

    2015-01-01

    Objectives The study was conducted to check the reliability of India-specific regression formula for age estimation of population in and around Bahadurgarh, Haryana (India). Materials and methods The study was conducted using digital orthopantomograms (OPGs) of 464 subjects (253 males and 211 females). Chronologic age (CA) was derived from that mentioned on the OPG. Each tooth in the left mandibular segment was scored using Demirjian's scoring and age was calculated using the regression formulas derived by Acharya. The difference of the chronologic and estimated age was used to check the reliability of India-specific regression formula. Results The mean estimated age was found to be significantly higher as compared to CA for overall as well as both the genders independently (p < 0.001). Difference (in ±) between estimated and CA ranged from 0 to 4.2 years. Mean difference in age was 0.85 ± 0.73 years for males and 0.87 ± 0.76 years for females. Conclusion The published India-specific regression formula does not have reliability in the population of Bahadurgarh, Haryana and hence cannot be universally applied. PMID:26587381

  13. Can you hear my age? Influences of speech rate and speech spontaneity on estimation of speaker age

    PubMed Central

    Skoog Waller, Sara; Eriksson, Mårten; Sörqvist, Patrik

    2015-01-01

    Cognitive hearing science is mainly about the study of how cognitive factors contribute to speech comprehension, but cognitive factors also partake in speech processing to infer non-linguistic information from speech signals, such as the intentions of the talker and the speaker’s age. Here, we report two experiments on age estimation by “naïve” listeners. The aim was to study how speech rate influences estimation of speaker age by comparing the speakers’ natural speech rate with increased or decreased speech rate. In Experiment 1, listeners were presented with audio samples of read speech from three different speaker age groups (young, middle aged, and old adults). They estimated the speakers as younger when speech rate was faster than normal and as older when speech rate was slower than normal. This speech rate effect was slightly greater in magnitude for older (60–65 years) speakers in comparison with younger (20–25 years) speakers, suggesting that speech rate may gain greater importance as a perceptual age cue with increased speaker age. This pattern was more pronounced in Experiment 2, in which listeners estimated age from spontaneous speech. Faster speech rate was associated with lower age estimates, but only for older and middle aged (40–45 years) speakers. Taken together, speakers of all age groups were estimated as older when speech rate decreased, except for the youngest speakers in Experiment 2. The absence of a linear speech rate effect in estimates of younger speakers, for spontaneous speech, implies that listeners use different age estimation strategies or cues (possibly vocabulary) depending on the age of the speaker and the spontaneity of the speech. Potential implications for forensic investigations and other applied domains are discussed. PMID:26236259

  14. AGE AND MASS FOR 920 LARGE MAGELLANIC CLOUD CLUSTERS DERIVED FROM 100 MILLION MONTE CARLO SIMULATIONS

    SciTech Connect

    Popescu, Bogdan; Hanson, M. M.; Elmegreen, Bruce G. E-mail: margaret.hanson@uc.edu

    2012-06-01

    We present new age and mass estimates for 920 stellar clusters in the Large Magellanic Cloud (LMC) based on previously published broadband photometry and the stellar cluster analysis package, MASSCLEANage. Expressed in the generic fitting formula, d{sup 2} N/dMdt{proportional_to}M{sup {alpha}} t{sup {beta}}, the distribution of observed clusters is described by {alpha} = -1.5 to -1.6 and {beta} = -2.1 to -2.2. For 288 of these clusters, ages have recently been determined based on stellar photometric color-magnitude diagrams, allowing us to gauge the confidence of our ages. The results look very promising, opening up the possibility that this sample of 920 clusters, with reliable and consistent age, mass, and photometric measures, might be used to constrain important characteristics about the stellar cluster population in the LMC. We also investigate a traditional age determination method that uses a {chi}{sup 2} minimization routine to fit observed cluster colors to standard infinite-mass limit simple stellar population models. This reveals serious defects in the derived cluster age distribution using this method. The traditional {chi}{sup 2} minimization method, due to the variation of U, B, V, R colors, will always produce an overdensity of younger and older clusters, with an underdensity of clusters in the log (age/yr) = [7.0, 7.5] range. Finally, we present a unique simulation aimed at illustrating and constraining the fading limit in observed cluster distributions that includes the complex effects of stochastic variations in the observed properties of stellar clusters.

  15. Stability and control derivative estimates obtained from flight data for the Beech 99 aircraft

    NASA Technical Reports Server (NTRS)

    Tanner, R. R.; Montgomery, T. D.

    1979-01-01

    Lateral-directional and longitudinal stability and control derivatives were determined from flight data by using a maximum likelihood estimator for the Beech 99 airplane. Data were obtained with the aircraft in the cruise configuration and with one-third flap deflection. The estimated derivatives show good agreement with the predictions of the manufacturer.

  16. Maternal age, reproduction and chromosomal aberrations in Wistar derived rats.

    PubMed

    Niggeschulze, A; Kast, A

    1994-01-01

    The fertility of rats ranges from one to 18 months. In standard teratogenicity testing young, mature females are used which may not reflect the situation in women above 35 years old. Reproduction among different age groups of Wistar ats (strain Chbb: THOM) was compared at 3, 6, 9, 12, 15 and 18 months. At least 20 virgin females were inseminated per age group. The copulation rate did not differ between the groups. From the maternal age of 12 months, the pregnancy rate was significantly decreased, from the age of 9 months, the litter values were significantly lowered and the resorption rates were increased. Maternal age did not influence the incidence of fetal variations and malformations. Additionally, the chromosomal aberration rate in the bone marrow was evaluated in male and female rats. Twelve animals of each sex were scheduled per group, and studied at the age of 1, 3, 6, 12, 15, 18, 21 or 24 months. In males, the aberration rate increased continuously from 0.18 through 3%, while in females the increase continued from 0.33 to 2.29% at 15 months old when a plateau was reached. When testing new compounds for embryotoxicity or genotoxicity in female rats, the animals should be of comparable age to man in order to avoid a misinterpretation of spontaneous abnormalities. From these studies, however, it was concluded that the use of higher age groups of female rats in teratogenicity studies would not improve the risk assessment.

  17. Threshold groundwater ages and young water fractions estimated from 3H, 3He, and 14C

    NASA Astrophysics Data System (ADS)

    Kirchner, James; Jasechko, Scott

    2016-04-01

    It is widely recognized that a water sample taken from a running stream is not described by a single age, but rather by a distribution of ages. It is less widely recognized that the same principle holds true for groundwaters, as indicated by the commonly observed discordances between model ages obtained from different tracers (e.g., 3H vs 14C) in the same sample. Water age distributions are often characterized by their mean residence times (MRT's). However, MRT estimates are highly uncertain because they depend on the shape of the assumed residence time distribution (in particular on the thickness of the long-time tail), which is difficult or impossible to constrain with data. Furthermore, because MRT's are typically nonlinear functions of age tracer concentrations, they are subject to aggregation bias. That is, MRT estimates derived from a mixture of waters with different ages (and thus different tracer concentrations) will systematically underestimate the mixture's true mean age. Here, building on recent work with stable isotope tracers in surface waters [1-3], we present a new framework for using 3H, 3He and 14C to characterize groundwater age distributions. Rather than describing groundwater age distributions by their MRT, we characterize them by the fraction of the distribution that is younger or older than a threshold age. The threshold age that separates "young" from "old" water depends on the characteristics of the specific tracer, including its history of atmospheric inputs. Our approach depends only on whether a given slice of the age distribution is younger or older than the threshold age, but not on how much younger or older it is. Thus our approach is insensitive to the tails of the age distribution, and is therefore relatively unaffected by uncertainty in the distribution's shape. Here we show that concentrations of 3H, 3He, and 14C are almost linearly related to the fractions of water that are younger or older than specified threshold ages. These

  18. Estimates of surface roughness derived from synthetic aperture radar (SAR) data

    NASA Technical Reports Server (NTRS)

    Evans, Diane L.; Farr, Tom G.; Van Zyl, Jakob J.

    1992-01-01

    Radar remote sensing data provide a unique perspective of the earth's crust and the processes that have influenced its evolution. Physically based models are required, however, to relate the geophysical quantities being measured by the radar sensor to useful geologic information. In this study, synthetic aperture radar (SAR) data over the Cima volcanic field in the Mojave Desert of California are quantitatively connected with microtopography through inversion of a radar backscatter model. Changes in surface roughness inferred from the derived microtopography are modeled and found to be consistent with aeolian mantling as surfaces age. Estimated rates of aeolian deposition for the Cima area are compared to the Lunar Crater volcanic field in Nevada. Rates of deposition appear to be higher at Cima volcanic field, most likely because of its proximity to Soda Lake, the main source of the aeolian material.

  19. So You Think You Look Young? Matching Older Adults' Subjective Ages with Age Estimations Provided by Younger, Middle-Aged, and Older Adults

    ERIC Educational Resources Information Center

    Kotter-Gruhn, Dana; Hess, Thomas M.

    2012-01-01

    Perceived age plays an important role in the context of age identity and social interactions. To examine how accurate individuals are in estimating how old they look and how old others are, younger, middle-aged, and older adults rated photographs of older target persons (for whom we had information about objective and subjective age) in terms of…

  20. Linear Prediction of a True Score from a Direct Estimate and Several Derived Estimates

    ERIC Educational Resources Information Center

    Haberman, Shelby J.; Qian, Jiahe

    2007-01-01

    Statistical prediction problems often involve both a direct estimate of a true score and covariates of this true score. Given the criterion of mean squared error, this study determines the best linear predictor of the true score given the direct estimate and the covariates. Results yield an extension of Kelley's formula for estimation of the true…

  1. A Comparison of Different Age Estimation Methods of the Adult Pelvis.

    PubMed

    Miranker, Molly

    2016-09-01

    The adult human pelvis is useful to estimate age because it contains three age indicators-the pubic symphysis, auricular surface, and acetabulum. This study tested the accuracy, inaccuracy, and bias of age estimation from the Suchey-Brooks pubic symphysis, Osborne auricular surface, Rissech and Calce acetabulum aging methods, and a summary age of these indicators. The study sample consisted of 212 White individuals with known age and sex from the William M. Bass Donated Skeletal Collection. The Rissech method performed the best, was the most accurate method with smallest inaccuracy and bias, followed by the Osborne, Suchey-Brooks, summary age, and then Calce methods. Though the Pearson correlation showed only the Suchey-Brooks method to correlate significantly with known age, it is likely the Suchey-Brooks study sample coincidentally reflected the age distribution of this test sample. Results suggested that Bayesian prediction may improve age estimation and should be applied to other age indicators.

  2. Estimating Aircraft Heading Based on Laserscanner Derived Point Clouds

    NASA Astrophysics Data System (ADS)

    Koppanyi, Z.; Toth, C., K.

    2015-03-01

    Using LiDAR sensors for tracking and monitoring an operating aircraft is a new application. In this paper, we present data processing methods to estimate the heading of a taxiing aircraft using laser point clouds. During the data acquisition, a Velodyne HDL-32E laser scanner tracked a moving Cessna 172 airplane. The point clouds captured at different times were used for heading estimation. After addressing the problem and specifying the equation of motion to reconstruct the aircraft point cloud from the consecutive scans, three methods are investigated here. The first requires a reference model to estimate the relative angle from the captured data by fitting different cross-sections (horizontal profiles). In the second approach, iterative closest point (ICP) method is used between the consecutive point clouds to determine the horizontal translation of the captured aircraft body. Regarding the ICP, three different versions were compared, namely, the ordinary 3D, 3-DoF 3D and 2-DoF 3D ICP. It was found that 2-DoF 3D ICP provides the best performance. Finally, the last algorithm searches for the unknown heading and velocity parameters by minimizing the volume of the reconstructed plane. The three methods were compared using three test datatypes which are distinguished by object-sensor distance, heading and velocity. We found that the ICP algorithm fails at long distances and when the aircraft motion direction perpendicular to the scan plane, but the first and the third methods give robust and accurate results at 40m object distance and at ~12 knots for a small Cessna airplane.

  3. 76 FR 37314 - Estimates of the Voting Age Population for 2010

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-27

    ... Office of the Secretary Estimates of the Voting Age Population for 2010 AGENCY: Office of the Secretary, Commerce. ACTION: General Notice Announcing Population Estimates. SUMMARY: This notice announces the voting age population estimates as of July 1, 2010, for each state and the District of Columbia. We...

  4. 75 FR 4343 - Estimates of the Voting Age Population for 2009

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-27

    ... Office of the Secretary Estimates of the Voting Age Population for 2009 AGENCY: Office of the Secretary, Commerce. ACTION: General Notice Announcing Population Estimates. SUMMARY: This notice announces the voting age population estimates as of July 1, 2009, for each state and the District of Columbia. We...

  5. 78 FR 6289 - Estimates of the Voting Age Population for 2012

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-30

    ... Office of the Secretary Estimates of the Voting Age Population for 2012 AGENCY: Office of the Secretary, Commerce. ] ACTION: General notice announcing population estimates. SUMMARY: This notice announces the voting age population estimates as of July 1, 2012, for each state and the District of Columbia. We...

  6. 77 FR 4000 - Estimates of the Voting Age Population for 2011

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-26

    ... Office of the Secretary Estimates of the Voting Age Population for 2011 AGENCY: Office of the Secretary, Commerce. ACTION: General Notice Announcing Population Estimates. SUMMARY: This notice announces the voting age population estimates as of July 1, 2011, for each state and the District of Columbia. We...

  7. Postmenopausal Motherhood Reloaded: Advanced Age and In Vitro Derived Gametes

    PubMed Central

    Cutas, Daniela; Smajdor, Anna

    2015-01-01

    In this paper we look at the implications of an emerging technology for the case in favor of, or against, postmenopausal motherhood. Technologies such as in vitro derived gametes (sperm and eggs derived from nonreproductive cells) have the potential to influence the ways in which reproductive medicine is practiced, and are already bringing new dimensions to debates in this area. We explain what in vitro derived gametes are and how their development may impact on the case of postmenopausal motherhood. We briefly review some of the concerns that postmenopausal motherhood has raised—and the implications that the successful development, and use in reproduction, of artificial gametes might have for such concerns. The concerns addressed include arguments from nature, risks and efficacy, reduced energy of the mother, and maternal life expectancy. We also consider whether the use of in vitro derived gametes to facilitate postmenopausal motherhood would contribute to reinforcing a narrow, geneticized account of reproduction and a pro-reproductive culture that encourages women to produce genetically related offspring at all costs. PMID:26074667

  8. Ultrasound-Derived Forearm Muscle Thickness Is a Powerful Predictor for Estimating DXA-Derived Appendicular Lean Mass in Japanese Older Adults.

    PubMed

    Abe, Takashi; Fujita, Eiji; Thiebaud, Robert S; Loenneke, Jeremy P; Akamine, Takuya

    2016-09-01

    To test the validity of published equations, anterior forearm muscle thickness (MT-ulna) of 158 Japanese older adults (72 men and 86 women) aged 50-79 y was measured with ultrasound. Appendicular lean soft tissue mass (aLM) was estimated from MT-ulna using two equations (body height without [eqn 1] and with [eqn 2]) previously published in the literature. Appendicular lean mass was measured using dual-energy X-ray absorption (DXA), and this method served as the reference criterion. There was a strong correlation between DXA-derived and ultrasound-estimated aLM in both equations (r = 0.882 and r = 0.944). Total error was 2.60 kg for eqn (1) and 1.38 kg for eqn (2). A Bland-Altman plot revealed that there was no systematic bias between DXA-derived and ultrasound-estimated aLM; however, eqn (1) overestimated aLM compared with DXA-derived aLM. Our results suggest that an ultrasound MT-ulna equation that includes body height is appropriate and useful for estimating aLM in Japanese adults. PMID:27321173

  9. Estimation of Energy Consumption and Greenhouse Gas Emissions considering Aging and Climate Change in Residential Sector

    NASA Astrophysics Data System (ADS)

    Lee, M.; Park, C.; Park, J. H.; Jung, T. Y.; Lee, D. K.

    2015-12-01

    The impacts of climate change, particularly that of rising temperatures, are being observed across the globe and are expected to further increase. To counter this phenomenon, numerous nations are focusing on the reduction of greenhouse gas (GHG) emissions. Because energy demand management is considered as a key factor in emissions reduction, it is necessary to estimate energy consumption and GHG emissions in relation to climate change. Further, because South Korea is the world's fastest nation to become aged, demographics have also become instrumental in the accurate estimation of energy demands and emissions. Therefore, the purpose of this study is to estimate energy consumption and GHG emissions in the residential sectors of South Korea with regard to climate change and aging to build more accurate strategies for energy demand management and emissions reduction goals. This study, which was stablished with 2010 and 2050 as the base and target years, respectively, was divided into a two-step process. The first step evaluated the effects of aging and climate change on energy demand, and the second estimated future energy use and GHG emissions through projected scenarios. First, aging characteristics and climate change factors were analyzed by using the logarithmic mean divisia index (LMDI) decomposition analysis and the application of historical data. In the analysis of changes in energy use, the effects of activity, structure, and intensity were considered; the degrees of contribution were derived from each effect in addition to their relations to energy demand. Second, two types of scenarios were stablished based on this analysis. The aging scenarios are business as usual and future characteristics scenarios, and were used in combination with Representative Concentration Pathway (RCP) 2.6 and 8.5. Finally, energy consumption and GHG emissions were estimated by using a combination of scenarios. The results of these scenarios show an increase in energy consumption

  10. Impact of age, sleep pressure and circadian phase on time-of-day estimates.

    PubMed

    Späti, Jakub; Münch, Mirjam; Blatter, Katharina; Knoblauch, Vera; Jones, Luke A; Cajochen, Christian

    2009-07-19

    Orientation and self-location within the temporal fabric of the environment involves multiple organismic systems. While temporal self-location on the physiological level has been known for some time to be based on a 'biological clock' located within the hypothalamus, the mechanisms that participate in temporal position finding on the cognitive level are not yet fully understood. In order to probe the mechanisms that underlie this faculty, verbal estimates on time-of-day were collected at 3.75-h intervals from 16 young (7 males, 8 females; 20-31 years) and 16 older (8 males, 8 females; 57-74 years) subjects in a balanced crossover design during 40-h epochs of prolonged wakefulness and 40-h epochs of sleep satiation spent under constant routine conditions. An overestimation of clock time during prolonged wakefulness was found in both age-groups, with significantly larger errors for the older group (young: 0.5+/-0.2h; older: 1.5+/-0.2h, p<0.05). In both age-groups, estimation errors ran roughly parallel to the time course of core body temperature. However a significant interaction between time-of-day and age-group was observed (rANOVA, p<0.05): younger subjects exhibited similar estimation errors as the older subjects after 16 h of prior wakefulness, whereas the latter did not manifest decrements under high sleep pressure. Data collected under conditions of sleep satiation also displayed a diurnal oscillation in estimation errors and a general overestimation (young: 0.8+/-0.2h; older: 1.3+/-0.3h, p<0.05). Here however, the age-groups did not differ significantly nor was there an interactive effect between time-of-day and age-group. The effects of age, duration of wake time and circadian phase on temporal position finding are in line with predictions based on the idea that awareness about current position in time is derived from interval timing processes.

  11. Rainfall estimation using raingages and radar — A Bayesian approach: 1. Derivation of estimators

    NASA Astrophysics Data System (ADS)

    Seo, D.-J.; Smith, J. A.

    1991-03-01

    Procedures for estimating rainfall from radar and raingage observations are constructed in a Bayesian framework. Given that the number of raingage measurements is typically very small, mean and variance of gage rainfall are treated as uncertain parameters. Under the assumption that log gage rainfall and log radar rainfall are jointly multivariate normal, the estimation problem is equivalent to lognormal co-kriging with uncertain mean and variance of the gage rainfall field. The posterior distribution is obtained under the assumption that the prior for the mean and inverse of the variance of log gage rainfall is normal-gamma 2. Estimate and estimation variance do not have closed-form expressions, but can be easily evaluated by numerically integrating two single integrals. To reduce computational burden associated with evaluating sufficient statistics for the likelihood function, an approximate form of parameter updating is given. Also, as a further approximation, the parameters are updated using raingage measurements only, yielding closed-form expressions for estimate and estimation variance in the Gaussian domain. With a reduction in the number of radar rainfall data in constructing covariance matrices, computational requirements for the estimation procedures are not significantly greater than those for simple co-kriging. Given their generality, the estimation procedures constructed in this work are considered to be applicable in various estimation problems involving an undersampled main variable and a densely sampled auxiliary variable.

  12. Simultaneous estimation of phase derivative and phase using parallel Kalman filter implementation

    NASA Astrophysics Data System (ADS)

    Kulkarni, Rishikesh; Rastogi, Pramod

    2016-06-01

    This paper proposes a technique for the simultaneous estimation of interference phase derivative and phase from a complex interferogram recorded in an optical interferometric setup. The complex interferogram is represented as a spatially varying autoregressive process in a given row or column at a time. The phase derivative is estimated from the poles of the transfer function representation of the autoregressive process. The poles are computed using the spatially varying autoregressive coefficients which are estimated by a computationally efficient Rauch-Tung-Striebel smoothing algorithm. The estimated phase derivative is used as a control input to a state space model designed for the phase estimation at each pixel. The unscented Kalman filter is utilized to deal with the nonlinear measurement process for the accurate estimation of the unwrapped phase. Numerical and experimental results substantiate the ability of the proposed method in handling noisy phase fringe patterns.

  13. Simultaneous estimation of phase derivative and phase using parallel Kalman filter implementation

    NASA Astrophysics Data System (ADS)

    Kulkarni, Rishikesh; Rastogi, Pramod

    2016-06-01

    This paper proposes a technique for the simultaneous estimation of interference phase derivative and phase from a complex interferogram recorded in an optical interferometric setup. The complex interferogram is represented as a spatially varying autoregressive process in a given row or column at a time. The phase derivative is estimated from the poles of the transfer function representation of the autoregressive process. The poles are computed using the spatially varying autoregressive coefficients which are estimated by a computationally efficient Rauch–Tung–Striebel smoothing algorithm. The estimated phase derivative is used as a control input to a state space model designed for the phase estimation at each pixel. The unscented Kalman filter is utilized to deal with the nonlinear measurement process for the accurate estimation of the unwrapped phase. Numerical and experimental results substantiate the ability of the proposed method in handling noisy phase fringe patterns.

  14. Reactivity measurement in estimation of benzoquinone and benzoquinone derivatives' allergenicity.

    PubMed

    Mbiya, Wilbes; Chipinda, Itai; Simoyi, Reuben H; Siegel, Paul D

    2016-01-01

    Benzoquinone (BQ) and benzoquinone derivatives (BQD) are used in the production of dyes and cosmetics. While BQ, an extreme skin sensitizer, is an electrophile known to covalently modify proteins via Michael Addition (MA) reaction whilst halogen substituted BQD undergo nucleophilic vinylic substitution (SNV) mechanism onto amine and thiol moieties on proteins, the allergenic effects of adding substituents on BQ have not been reported. The effects of inserting substituents on the BQ ring has not been studied in animal assays. However, mandated reduction/elimination of animals used in cosmetics testing in Europe has led to an increased need for alternatives for the prediction of skin sensitization potential. Electron withdrawing and electron donating substituents on BQ were assessed for effects on BQ reactivity toward nitrobenzene thiol (NBT). The NBT binding studies demonstrated that addition of EWG to BQ as exemplified by the chlorine substituted BQDs increased reactivity while addition of EDG as in the methyl substituted BQDs reduced reactivity. BQ and BQD skin allerginicity was evaluated in the murine local lymph node assay (LLNA). BQD with electron withdrawing groups had the highest chemical potency followed by unsubstituted BQ and the least potent were the BQD with electron donating groups. The BQD results demonstrate the impact of inductive effects on both BQ reactivity and allergenicity, and suggest the potential utility of chemical reactivity data for electrophilic allergen identification and potency ranking. PMID:26612505

  15. Improving lidar-derived turbulence estimates for wind energy

    DOE PAGES

    Newman, Jennifer F.; Clifton, Andrew

    2016-07-08

    Remote sensing devices such as lidars are currently being investigated as alternatives to cup anemometers on meteorological towers. Although lidars can measure mean wind speeds at heights spanning an entire turbine rotor disk and can be easily moved from one location to another, they measure different values of turbulence than an instrument on a tower. Current methods for improving lidar turbulence estimates include the use of analytical turbulence models and expensive scanning lidars. While these methods provide accurate results in a research setting, they cannot be easily applied to smaller, commercially available lidars in locations where high-resolution sonic anemometer datamore » are not available. Thus, there is clearly a need for a turbulence error reduction model that is simpler and more easily applicable to lidars that are used in the wind energy industry. In this work, a new turbulence error reduction algorithm for lidars is described. The algorithm, L-TERRA, can be applied using only data from a stand-alone commercially available lidar and requires minimal training with meteorological tower data. The basis of L-TERRA is a series of corrections that are applied to the lidar data to mitigate errors from instrument noise, volume averaging, and variance contamination. These corrections are applied in conjunction with a trained machine-learning model to improve turbulence estimates from a vertically profiling WINDCUBE v2 lidar. L-TERRA was tested on data from three sites – two in flat terrain and one in semicomplex terrain. L-TERRA significantly reduced errors in lidar turbulence at all three sites, even when the machine-learning portion of the model was trained on one site and applied to a different site. Errors in turbulence were then related to errors in power through the use of a power prediction model for a simulated 1.5 MW turbine. L-TERRA also reduced errors in power significantly at all three sites, although moderate power errors remained for

  16. Estimation of lower crust magnetization form satellite derived anomaly field

    NASA Technical Reports Server (NTRS)

    Schnetzler, C. C.; Allenby, R. J.

    1983-01-01

    Various lines of evidence point to the lower crust as the source of the long-wavelength magnetic anomaly field measured by the POGO and Magsat satellites. Using seismically determined lower crust thicknesses and equivalent source inversion of the satellite anomaly data, magnetization for the lower crust for much of the United States has been calculated. The average magnetization for two hundred sixty-six 150 x 150 km areas is 3.5 A/m with a standard deviation of 1.1 A/m. These values are consistent with laboratory measurements of mafic-ultramafic rocks expected in the lower crust, and in agreement with previous estimates of lower crust magnetization based on long-wavelength aeromagnetic data. Average lower crust thickness for the same areas is 18.2 km (sigma = 6.4). Thus, over large regions, it appears that variation in magnetization and variation in magnetic layer thickness contribute almost equally in causing the anomaly field variation at satellite altitude.

  17. Using the acetabulum to estimate age at death of adult males.

    PubMed

    Rissech, Carme; Estabrook, George F; Cunha, Eugenia; Malgosa, Assumpció

    2006-03-01

    The acetabular region is often present and adequately preserved in adult human skeletal remains. Close morphological examination of the 242 left male os coxae from the identified collection of Coimbra (Portugal) has enabled the recognition of seven variables that can be used to estimate age at death. This paper describes these variables and argues their appropriateness by analyzing the correlation between these criteria and the age, the intra- and interobserver consistence, and the accuracy in age prediction using Bayesian inference to estimate age of identified specimens. Results show significant close correlation between the acetabular criteria and age, nonsignificant differences in intra- and interobserver test, and 89% accuracy in Bayes prediction. Obtained estimated age of the specimens had similar accuracy in all ages. These results indicate that these seven variables, based on the acetabular area, are potentially useful to estimate age at death for adult specimens.

  18. EURRECA-Estimating iodine requirements for deriving dietary reference values.

    PubMed

    Ristić-Medić, Danijela; Novaković, Romana; Glibetić, Maria; Gurinović, Mirjana

    2013-01-01

    Iodine is an essential component of thyroid hormones, and current recommendations for intake are based on urinary iodine excretion, assessment of thyroid size, thyroidal iodine accumulation and turnover, radioactive iodine uptake, balance studies, and epidemiological studies. Dietary iodine is rapidly and almost completely absorbed. The prevalence of inadequate iodine intake is high: 29% of the world's population lives in iodine-deficient areas and 44% of Europe remains mildly iodine deficient. To assess current data and update evidence for setting dietary recommendations for iodine, the EURRECA Network of Excellence has undertaken systematic review and evaluation of (i) the usefulness of iodine status biomarkers (ii) the relationship between iodine status biomarkers and dietary iodine intake, and (iii) the relationship between iodine intake and health outcomes (endemic goiter, hypothyroidism, and cognitive function). This review summarizes the main research outputs: the key findings of the literature review, results of the meta-analyses, and discussion of the main conclusions. Currently, data for relevant intake-status-health relationships for iodine are limited, particularly for population groups such as children under two years, pregnant women, and the elderly. The EURRECA Network developed best practice guidelines for the identification of pertinent iodine studies based on a systematic review approach. This approach aimed to identify comparable data, suitable for meta-analysis, for different countries and across all age ranges. When new data are available, the EURRECA Network best practice guidelines will provide a better understanding of iodine requirements for different health outcomes which could be used to set evidence-based dietary iodine recommendations for optimal health. PMID:23952087

  19. Age estimation by measuring open apices of lower erupted teeth in 12-16 years olds by radiographic evaluation.

    PubMed

    Jatti, Deepa; Kantaraj, Yashodadevi; Nagaraju, Rakesh; Janardhan, Sujatha; Nataraj, Santana

    2013-07-01

    The purpose of this study was to estimate chronological age from panoramic radiographs by measuring open apices of seven right or left mandibular teeth in children of South Indian origin. A total of 101 male and female patients aged between 12 and 16 years were selected. The panoramic radiographs of the patient were indirectly digitised. The variables N0, x3, x4, x5, x6, x7 and s were measured using a computer-aided drafting program. Statistical analysis was performed to derive a regression equation for estimation of age. Two variables x3 and x7 contributed significantly to the fit, yielding the following linear regression formula: Age = 16.025-9.445 (x7) + 1.620 (x3). Statistical analysis indicated that the regression equation explained 97.5% of total variance (R(2) = 0.975). The median of the residuals was -0.0348 years with an interquartile range (IQR) of 0.2520 years. The derived regression equations from these variables can serve as an invaluable tool in estimating the age of children between 12 and 16 years of South Indian origin. PMID:23756511

  20. Estimation of central aortic pressure waveform features derived from the brachial cuff volume displacement waveform.

    PubMed

    Butlin, Mark; Qasem, Ahmad; Avolio, Alberto P

    2012-01-01

    There is increasing interest in non-invasive estimation of central aortic waveform parameters in the clinical setting. However, controversy has arisen around radial tonometric based systems due to the requirement of a trained operator or lack of ease of use, especially in the clinical environment. A recently developed device utilizes a novel algorithm for brachial cuff based assessment of aortic pressure values and waveform (SphygmoCor XCEL, AtCor Medical). The cuff was inflated to 10 mmHg below an individual's diastolic blood pressure and the brachial volume displacement waveform recorded. The aortic waveform was derived using proprietary digital signal processing and transfer function applied to the recorded waveform. The aortic waveform was also estimated using a validated technique (radial tonometry based assessment, SphygmoCor, AtCor Medical). Measurements were taken in triplicate with each device in 30 people (17 female) aged 22 to 79 years of age. An average for each device for each individual was calculated, and the results from the two devices were compared using regression and Bland-Altman analysis. A high correlation was found between the devices for measures of aortic systolic (R(2)=0.99) and diastolic (R(2)=0.98) pressure. Augmentation index and subendocardial viability ratio both had a between device R(2) value of 0.82. The difference between devices for measured aortic systolic pressure was 0.5±1.8 mmHg, and for augmentation index, 1.8±7.0%. The brachial cuff based approach, with an individualized sub-diastolic cuff pressure, provides an operator independent method of assessing not only systolic pressure, but also aortic waveform features, comparable to existing validated tonometric-based methods.

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

    PubMed Central

    Steenkamp, Gerhard; Groom, Rosemary J.

    2016-01-01

    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

  2. Age estimation by measurements of developing teeth: accuracy of Cameriere's method on a Brazilian sample.

    PubMed

    Fernandes, Mário Marques; Tinoco, Rachel Lima Ribeiro; de Braganca, Daniel Pereira Parreiras; de Lima, Silas Henrique Rabelo; Francesquini Junior, Luiz; Daruge Junior, Eduardo

    2011-11-01

    Developing teeth are commonly the criteria used for age estimation in children and young adults. The method developed by Cameriere et al. (Int J Legal Med 2006;120:49-52) is based on measures of teeth with open apex, and application of a formula, to estimate chronological age of children. The present study evaluated a sample of panoramic radiographs from Brazilian children from 5 to 15 years of age, to evaluate the accuracy of the method proposed by Cameriere et al. The results has proven the system reliable for age estimation, with a median residual error of -0.014 years between chronological and estimated ages (p = 0.603). There was a slight tendency to overestimate the ages of 5-10 years and underestimate the ages of 11-15 years.

  3. Comparison of accuracy between dental and skeletal age in the estimation of chronological age of Down syndrome individuals.

    PubMed

    Hala, Leila Abou; Moraes, Mari Eli Leonelli de; Villaça-Carvalho, Maria Fernanda Lima; de Castro Lopes, Sérgio Lúcio Pereira; Gamba, Thiago de Oliveira

    2016-09-01

    This study aimed to evaluate the accuracy of dental age (DA) and skeletal age (SA) methods in order to estimate chronological age (CA) in individuals with Down syndrome (DS), contributing to the Forensic Dentistry and making the identification of these individuals age possible. For this, 278 images of individuals were selected and divided in 2 groups: 216 non-DS patients and 62 with DS. At first, DA was evaluated by Nolla method, on panoramic radiographs, followed by SA, evaluated by Greulich and Pyle method. The linear correlation coefficient of Pearson was used for the analysis of concordance between the methods. Paired t-test with confidence interval was used to evaluate the accuracy and Bland and Altman method was applied to estimate limits of concordance. Complementary to this first analysis, descriptive statistics and ANOVA test were applied for comparison among chronological age (CA), dental age (DA) and skeletal age (SA), with a significance level of 95% (p≥0.05), ordering to observe the differences among them. DA, estimated by Nolla, is underestimated in both, DS and non-DS individuals, and it is more notable in DS individuals. SA estimated by Greulich and Pyle method is overestimated, except for non-DS males. The range of variance is greater in SA and DS than DA and non-DS individuals, respectively. A greater accordance was found for DA×CA if compared to SA×CA, indicating that DA, estimated by Nolla method, is more accurate than SA, evaluated by Greulich and Pyle method, for estimating CA of both, DS and non-DS individuals. However, neither method seems to be precise and more caution is required for age estimation in DS individuals. PMID:27426840

  4. Comparison of accuracy between dental and skeletal age in the estimation of chronological age of Down syndrome individuals.

    PubMed

    Hala, Leila Abou; Moraes, Mari Eli Leonelli de; Villaça-Carvalho, Maria Fernanda Lima; de Castro Lopes, Sérgio Lúcio Pereira; Gamba, Thiago de Oliveira

    2016-09-01

    This study aimed to evaluate the accuracy of dental age (DA) and skeletal age (SA) methods in order to estimate chronological age (CA) in individuals with Down syndrome (DS), contributing to the Forensic Dentistry and making the identification of these individuals age possible. For this, 278 images of individuals were selected and divided in 2 groups: 216 non-DS patients and 62 with DS. At first, DA was evaluated by Nolla method, on panoramic radiographs, followed by SA, evaluated by Greulich and Pyle method. The linear correlation coefficient of Pearson was used for the analysis of concordance between the methods. Paired t-test with confidence interval was used to evaluate the accuracy and Bland and Altman method was applied to estimate limits of concordance. Complementary to this first analysis, descriptive statistics and ANOVA test were applied for comparison among chronological age (CA), dental age (DA) and skeletal age (SA), with a significance level of 95% (p≥0.05), ordering to observe the differences among them. DA, estimated by Nolla, is underestimated in both, DS and non-DS individuals, and it is more notable in DS individuals. SA estimated by Greulich and Pyle method is overestimated, except for non-DS males. The range of variance is greater in SA and DS than DA and non-DS individuals, respectively. A greater accordance was found for DA×CA if compared to SA×CA, indicating that DA, estimated by Nolla method, is more accurate than SA, evaluated by Greulich and Pyle method, for estimating CA of both, DS and non-DS individuals. However, neither method seems to be precise and more caution is required for age estimation in DS individuals.

  5. Estimation of gestational age, using neonatal anthropometry: a cross-sectional study in India.

    PubMed

    Thawani, Rajat; Dewan, Pooja; Faridi, M M A; Arora, Shilpa Khanna; Kumar, Rajeev

    2013-12-01

    Prematurity is a significant contributor to neonatal mortality in India. Conventionally, assessment of gestational age of newborns is based on New Ballard Technique, for which a paediatric specialist is needed. Anthropometry of the newborn, especially birthweight, has been used in the past to predict the gestational age of the neonate in peripheral health facilities where a trained paediatrician is often not available. We aimed to determine if neonatal anthropometric parameters, viz. birthweight, crown heel-length, head-circumference, mid-upper arm-circumference, lower segment-length, foot-length, umbilical nipple distance, calf-circumference, intermammary distance, and hand-length, can reliably predict the gestational age. The study also aimed to derive an equation for the same. We also assessed if these neonatal anthropometric parameters had a better prediction of gestational age when used in combination compared to individual parameters. We evaluated 1,000 newborns in a cross-sectional study conducted in Guru Teg Bahadur Hospital in Delhi. Detailed anthropometric estimation of the neonates was done within 48 hours after birth, using standard techniques. Gestational age was estimated using New Ballard Scoring. Out of 1,250 consecutive neonates, 1,000 were included in the study. Of them, 800 randomly-selected newborns were used in devising the model, and the remaining 200 newborns were used in validating the final model. Quadratic regression analysis using stepwise selection was used in building the predictive model. Birthweight (R=0.72), head-circumference (R = 0.60), and mid-upper arm-circumference (R = 0.67) were found highly correlated with gestation. The final equation to assess gestational age was as follows: Gestational age (weeks) = 5.437 x W-0.781 x W(2) + 2.815 x HC-0.041 x HC(2) + 0.285 x MUAC-22.745 where W=Weight, HC=Head-circumference and MUAC=Mid-upper arm-circumference; Adjusted R = 0.76. On validation, the predictability of this equation is 46

  6. Estimation of Gestational Age, Using Neonatal Anthropometry: A Cross-sectional Study in India

    PubMed Central

    Thawani, Rajat; Faridi, M.M.A.; Arora, Shilpa Khanna; Kumar, Rajeev

    2013-01-01

    Prematurity is a significant contributor to neonatal mortality in India. Conventionally, assessment of gestational age of newborns is based on New Ballard Technique, for which a paediatric specialist is needed. Anthropometry of the newborn, especially birthweight, has been used in the past to predict the gestational age of the neonate in peripheral health facilities where a trained paediatrician is often not available. We aimed to determine if neonatal anthropometric parameters, viz. birthweight, crown heel-length, head-circumference, mid-upper arm-circumference, lower segment-length, foot-length, umbilical nipple distance, calf-circumference, intermammary distance, and hand-length, can reliably predict the gestational age. The study also aimed to derive an equation for the same. We also assessed if these neonatal anthropometric parameters had a better prediction of gestational age when used in combination compared to individual parameters. We evaluated 1,000 newborns in a cross-sectional study conducted in Guru Teg Bahadur Hospital in Delhi. Detailed anthropometric estimation of the neonates was done within 48 hours after birth, using standard techniques. Gestational age was estimated using New Ballard Scoring. Out of 1,250 consecutive neonates, 1,000 were included in the study. Of them, 800 randomly-selected newborns were used in devising the model, and the remaining 200 newborns were used in validating the final model. Quadratic regression analysis using stepwise selection was used in building the predictive model. Birthweight (R=0.72), head-circumference (R=0.60), and mid-upper arm-circumference (R=0.67) were found highly correlated with gestation. The final equation to assess gestational age was as follows: Gestational age (weeks)=5.437×W–0.781×W2+2.815×HC–0.041×HC2+0.285×MUAC–22.745 where W=Weight, HC=Head-circumference and MUAC=Mid-upper arm-circumference; Adjusted R=0.76. On validation, the predictability of this equation is 46% (±1 week), 75

  7. Thermoluminescence and new 14C age estimates for late quaternary loesses in southwestern Nebraska

    USGS Publications Warehouse

    Maat, P.B.; Johnson, W.C.

    1996-01-01

    Loess of late Quaternary age mantles most of Nebraska south of the Platte River Valley. At least five late Quaternary loesses are recognized: from oldest to youngest, one or more undifferentiated pre-lllinoian loesses, the Loveland Loess, the Gilman Canyon Loess, which exhibits a well developed soil and rests unconformably on the Sangamon soil, the Peoria Loess capped by the Brady soil, and the Bignell Loess, which is distributed discontinuously. Previous research shows that the Loveland Loess is Illinoian. the Gilman Canyon Loess and Peoria Loess are Wisconsin, and the Bignell Loess is Holocene. We present here the first thermoluminescence (TL) age estimates and new C ages for these late Quaternary loesses at two key sections in southwestern Nebraska, the Eustis ash pit and the Bignell Hill road cut. TL age estimates from all samples collected from Eustis ash pit and Bignell Hill were internally consistent. TL and C age estimates from these two sections generally agree and support previous age determinations. The TL age estimate on Loveland Loess indicates deposition at 163 ka. TL and radiocarbon age estimates indicate that Oilman Canyon Loess, believed to be deposited during the Farmdale interstade, first began to accumulate at about 40 ka: the lower part of the Gilman Canyon Loess is 36 ka at Eustis and the middle of the unit is 30 ka at Bignell Hill. The lower and upper parts of the Peoria Loess give age estimates of 24 ka and 17 ka, respectively. TL age estimates for deposition of the Bignell Loess are 9 ka near the base, in agreement with radiocarbon age estimates, and 6 ka immediately below the modern soil, substantiating its Holocene age. Comparisons of TL age estimates with ??18O and insolation curves which show loess deposition during interglacial and interstadial as well as glacial periods, indicate that loess deposition on the Great Plains can occur under a variety of climatic conditions.

  8. A Derivation of the Unbiased Standard Error of Estimate: The General Case.

    ERIC Educational Resources Information Center

    O'Brien, Francis J., Jr.

    This paper is part of a series of applied statistics monographs intended to provide supplementary reading for applied statistics students. In the present paper, derivations of the unbiased standard error of estimate for both the raw score and standard score linear models are presented. The derivations for raw score linear models are presented in…

  9. Canine pulp ratios in estimating pensionable age in subjects with questionable documents of identification.

    PubMed

    Cameriere, Roberto; Ferrante, Luigi

    2011-03-20

    One of the most interesting reasons for needing to estimate age in adult subjects is to ascertain the age of a person of questionable pensionable age. This problem is becoming increasingly important in Europe, owing to the high number of immigrants without valid birth certificates. The aim of this paper is to evaluate the application of the apposition of secondary dentine of canines by the method of Cameriere et al. [10], in order to estimate the pensionable age of subjects without proper birth certificates. Periapical X-rays of 180 canines from 90 subjects aged between 50 and 79, 46 men and 44 women, were analysed. Estimated ages were used to test the medico-legal question as to whether an individual was older or younger than 65 years of age. In subjects under 65, age was correctly evaluated in 91% and 89% of individuals using maxillary and mandibular canines, respectively. In subjects over 65, of pensionable age, estimates were correct in 85% and 88% of cases, respectively. The proportion of individuals with correct classifications was 89% for both maxillary and mandibular canines taken together. In only four subjects, the results of maxillary and mandibular canines were discordant; in the other 86 subjects, the test of maxillary and mandibular canines yielded concordant results. Among the latter, the proportion of individuals who were really aged 65 years or older, and who were correctly estimated as such, was 94%, and the proportion of individuals younger than 65 years of age who were correctly estimated as such was 96%.

  10. Re-Evaluating Neonatal-Age Models for Ungulates: Does Model Choice Affect Survival Estimates?

    PubMed Central

    Grovenburg, Troy W.; Monteith, Kevin L.; Jacques, Christopher N.; Klaver, Robert W.; DePerno, Christopher S.; Brinkman, Todd J.; Monteith, Kyle B.; Gilbert, Sophie L.; Smith, Joshua B.; Bleich, Vernon C.; Swanson, Christopher C.; Jenks, Jonathan A.

    2014-01-01

    New-hoof growth is regarded as the most reliable metric for predicting age of newborn ungulates, but variation in estimated age among hoof-growth equations that have been developed may affect estimates of survival in staggered-entry models. We used known-age newborns to evaluate variation in age estimates among existing hoof-growth equations and to determine the consequences of that variation on survival estimates. During 2001–2009, we captured and radiocollared 174 newborn (≤24-hrs old) ungulates: 76 white-tailed deer (Odocoileus virginianus) in Minnesota and South Dakota, 61 mule deer (O. hemionus) in California, and 37 pronghorn (Antilocapra americana) in South Dakota. Estimated age of known-age newborns differed among hoof-growth models and varied by >15 days for white-tailed deer, >20 days for mule deer, and >10 days for pronghorn. Accuracy (i.e., the proportion of neonates assigned to the correct age) in aging newborns using published equations ranged from 0.0% to 39.4% in white-tailed deer, 0.0% to 3.3% in mule deer, and was 0.0% for pronghorns. Results of survival modeling indicated that variability in estimates of age-at-capture affected short-term estimates of survival (i.e., 30 days) for white-tailed deer and mule deer, and survival estimates over a longer time frame (i.e., 120 days) for mule deer. Conversely, survival estimates for pronghorn were not affected by estimates of age. Our analyses indicate that modeling survival in daily intervals is too fine a temporal scale when age-at-capture is unknown given the potential inaccuracies among equations used to estimate age of neonates. Instead, weekly survival intervals are more appropriate because most models accurately predicted ages within 1 week of the known age. Variation among results of neonatal-age models on short- and long-term estimates of survival for known-age young emphasizes the importance of selecting an appropriate hoof-growth equation and appropriately defining intervals (i.e., weekly

  11. Re-evaluating neonatal-age models for ungulates: does model choice affect survival estimates?

    PubMed

    Grovenburg, Troy W; Monteith, Kevin L; Jacques, Christopher N; Klaver, Robert W; DePerno, Christopher S; Brinkman, Todd J; Monteith, Kyle B; Gilbert, Sophie L; Smith, Joshua B; Bleich, Vernon C; Swanson, Christopher C; Jenks, Jonathan A

    2014-01-01

    New-hoof growth is regarded as the most reliable metric for predicting age of newborn ungulates, but variation in estimated age among hoof-growth equations that have been developed may affect estimates of survival in staggered-entry models. We used known-age newborns to evaluate variation in age estimates among existing hoof-growth equations and to determine the consequences of that variation on survival estimates. During 2001-2009, we captured and radiocollared 174 newborn (≤24-hrs old) ungulates: 76 white-tailed deer (Odocoileus virginianus) in Minnesota and South Dakota, 61 mule deer (O. hemionus) in California, and 37 pronghorn (Antilocapra americana) in South Dakota. Estimated age of known-age newborns differed among hoof-growth models and varied by >15 days for white-tailed deer, >20 days for mule deer, and >10 days for pronghorn. Accuracy (i.e., the proportion of neonates assigned to the correct age) in aging newborns using published equations ranged from 0.0% to 39.4% in white-tailed deer, 0.0% to 3.3% in mule deer, and was 0.0% for pronghorns. Results of survival modeling indicated that variability in estimates of age-at-capture affected short-term estimates of survival (i.e., 30 days) for white-tailed deer and mule deer, and survival estimates over a longer time frame (i.e., 120 days) for mule deer. Conversely, survival estimates for pronghorn were not affected by estimates of age. Our analyses indicate that modeling survival in daily intervals is too fine a temporal scale when age-at-capture is unknown given the potential inaccuracies among equations used to estimate age of neonates. Instead, weekly survival intervals are more appropriate because most models accurately predicted ages within 1 week of the known age. Variation among results of neonatal-age models on short- and long-term estimates of survival for known-age young emphasizes the importance of selecting an appropriate hoof-growth equation and appropriately defining intervals (i.e., weekly

  12. Re-evaluating neonatal-age models for ungulates: Does model choice affect survival estimates?

    USGS Publications Warehouse

    Grovenburg, Troy W.; Monteith, Kevin L.; Jacques, Christopher N.; Klaver, Robert W.; DePerno, Christopher S.; Brinkman, Todd J.; Monteith, Kyle B.; Gilbert, Sophie L.; Smith, Joshua B.; Bleich, Vernon C.; Swanson, Christopher C.; Jenks, Jonathan A.

    2014-01-01

    New-hoof growth is regarded as the most reliable metric for predicting age of newborn ungulates, but variation in estimated age among hoof-growth equations that have been developed may affect estimates of survival in staggered-entry models. We used known-age newborns to evaluate variation in age estimates among existing hoof-growth equations and to determine the consequences of that variation on survival estimates. During 2001–2009, we captured and radiocollared 174 newborn (≤24-hrs old) ungulates: 76 white-tailed deer (Odocoileus virginianus) in Minnesota and South Dakota, 61 mule deer (O. hemionus) in California, and 37 pronghorn (Antilocapra americana) in South Dakota. Estimated age of known-age newborns differed among hoof-growth models and varied by >15 days for white-tailed deer, >20 days for mule deer, and >10 days for pronghorn. Accuracy (i.e., the proportion of neonates assigned to the correct age) in aging newborns using published equations ranged from 0.0% to 39.4% in white-tailed deer, 0.0% to 3.3% in mule deer, and was 0.0% for pronghorns. Results of survival modeling indicated that variability in estimates of age-at-capture affected short-term estimates of survival (i.e., 30 days) for white-tailed deer and mule deer, and survival estimates over a longer time frame (i.e., 120 days) for mule deer. Conversely, survival estimates for pronghorn were not affected by estimates of age. Our analyses indicate that modeling survival in daily intervals is too fine a temporal scale when age-at-capture is unknown given the potential inaccuracies among equations used to estimate age of neonates. Instead, weekly survival intervals are more appropriate because most models accurately predicted ages within 1 week of the known age. Variation among results of neonatal-age models on short- and long-term estimates of survival for known-age young emphasizes the importance of selecting an appropriate hoof-growth equation and appropriately defining intervals (i.e., weekly

  13. Re-evaluating neonatal-age models for ungulates: does model choice affect survival estimates?

    PubMed

    Grovenburg, Troy W; Monteith, Kevin L; Jacques, Christopher N; Klaver, Robert W; DePerno, Christopher S; Brinkman, Todd J; Monteith, Kyle B; Gilbert, Sophie L; Smith, Joshua B; Bleich, Vernon C; Swanson, Christopher C; Jenks, Jonathan A

    2014-01-01

    New-hoof growth is regarded as the most reliable metric for predicting age of newborn ungulates, but variation in estimated age among hoof-growth equations that have been developed may affect estimates of survival in staggered-entry models. We used known-age newborns to evaluate variation in age estimates among existing hoof-growth equations and to determine the consequences of that variation on survival estimates. During 2001-2009, we captured and radiocollared 174 newborn (≤24-hrs old) ungulates: 76 white-tailed deer (Odocoileus virginianus) in Minnesota and South Dakota, 61 mule deer (O. hemionus) in California, and 37 pronghorn (Antilocapra americana) in South Dakota. Estimated age of known-age newborns differed among hoof-growth models and varied by >15 days for white-tailed deer, >20 days for mule deer, and >10 days for pronghorn. Accuracy (i.e., the proportion of neonates assigned to the correct age) in aging newborns using published equations ranged from 0.0% to 39.4% in white-tailed deer, 0.0% to 3.3% in mule deer, and was 0.0% for pronghorns. Results of survival modeling indicated that variability in estimates of age-at-capture affected short-term estimates of survival (i.e., 30 days) for white-tailed deer and mule deer, and survival estimates over a longer time frame (i.e., 120 days) for mule deer. Conversely, survival estimates for pronghorn were not affected by estimates of age. Our analyses indicate that modeling survival in daily intervals is too fine a temporal scale when age-at-capture is unknown given the potential inaccuracies among equations used to estimate age of neonates. Instead, weekly survival intervals are more appropriate because most models accurately predicted ages within 1 week of the known age. Variation among results of neonatal-age models on short- and long-term estimates of survival for known-age young emphasizes the importance of selecting an appropriate hoof-growth equation and appropriately defining intervals (i.e., weekly

  14. The Technological Adolescent Age Transition: A Boundary to Estimate the Last Factor of the Drake Equation

    NASA Astrophysics Data System (ADS)

    Lemarchand, Guillermo A.

    2004-06-01

    Based on the study of several long-term societal indicators we estimate the phase transition between the ``Technological Adolescent Age'' (TAA) and the ``Technological Mature Age'' (TMA). Assuming the ``Principle of Mediocrity'' and using the Drake Equation we estimate a lower threshold for the number of technological civilizations in the galaxy.

  15. Seasonal comparisons of sea ice concentration estimates derived from SSM/I, OKEAN, and RADARSAT data

    USGS Publications Warehouse

    Belchansky, G.I.; Douglas, D.C.

    2002-01-01

    concentrations derived from OKEAN-01 and SSM/I satellite imagery were highly correlated during winter, spring, and fall, with mean differences of less than 8.1% (S.D. <15%) for the NASA Team algorithm, and less than 2.8% (S.D. <13.8%) for the Bootstrap algorithm. Respective differences between SSM/I NASA Team and SSM/I Bootstrap total concentrations were less than 5.3% (S.D. <6.9%). Monthly mean differences between SSM/I and OKEAN differed annually by less than 6%, with smaller differences primarily in winter. The NASA Team and Bootstrap algorithms underestimated the total sea ice concentrations relative to the RADARSAT ScanSAR no more than 3.0% (S.D. <9%) and 1.2% (S.D. <7.5%) during cold months, and no more than 12% and 7% during summer, respectively. ScanSAR tended to estimate higher ice concentrations for ice concentrations greater than 50%, when compared to SSM/I during all months. ScanSAR underestimated total sea ice concentration by 2% compared to the OKEAN-01 algorithm during cold months, and gave an overestimation by 2% during spring and summer months. Total NASA Team and Bootstrap sea ice concentration estimates derived from coincident SSM/I and OKEAN-01 data demonstrated mean differences of no more than 5.3% (S.D. <7%), 3.1% (S.D. <5.5%), 2.0% (S.D. <5.5%), and 7.3% (S.D. <10%) for fall, winter, spring, and summer periods, respectively. Large disagreements were observed between the OKEAN and NASA Team results in spring and summer for estimates of the first-year (FY) and multiyear (MY) age classes. The OKEAN-01 algorithm and data tended to estimate, on average, lower concentrations of young or FY ice and higher concentrations of total and MY ice for all months and seasons. Our results contribute to the growing body of documentation about the levels of disparity obtained when seasonal sea ice concentrations are estimated using various types of satellite data and algorithms. ?? 2002 Elsevier Science Inc. All rights reserved.

  16. Estimating migratory game-bird productivity by integrating age ratio and banding data

    USGS Publications Warehouse

    Zimmerman, G.S.; Link, W.A.; Conroy, M.J.; Sauer, J.R.; Richkus, K.D.; Boomer, G. Scott

    2010-01-01

    Implications: Several national and international management strategies for migratory game birds in North America rely on measures of productivity from harvest survey parts collections, without a justification of the estimator or providing estimates of precision. We derive an estimator of productivity with realistic measures of uncertainty that can be directly incorporated into management plans or ecological studies across large spatial scales.

  17. The lateral clavicular epiphysis: fusion timing and age estimation.

    PubMed

    Langley, Natalie R

    2016-03-01

    This study utilizes a forensic autopsy sample of twentieth century American Whites (the McCormick Clavicle Collection) to describe the morphology, variation, and fusion timing of the lateral clavicle epiphysis. Clavicles from individuals between 11 and 25 years at the time of death were used to document fusion of the lateral epiphysis (n= 133, 38 females and 95 males). The lateral epiphysis was scored as unfused, fusing, or fused. A linear weighted kappa indicates that this scoring method is highly replicable with almost perfect inter-rater agreement (kappa = 0.849), according to a widely used standard for assessing kappa values. Transition analysis, or probit regression, was employed to quantify fusion timing of the lateral epiphysis. The transition from "unfused" to "fusing" is most likely to occur at 16.5 years in females and 17.5 years in males. The transition from "fusing" to "fused" occurs at age 21 in females and age 20 in males. The earliest age at which fusion began was 15 years (n = 1), but the majority began fusing between 17 and 20 years. Most individuals (98.5 % of the sample) aged >24 years had fused lateral epiphyses. The epiphysis assumes one of two forms: (1) a separate bony flake fusing to the diaphysis or (2) a mound of bone glazing/smoothing over the diaphyseal surface. As socioeconomic status has been cited as the most influential variable on skeletal maturation rates, the fusion ages offered here should not be applied to populations with a socioeconomic status different from the greater US population.

  18. Summary of methods for calculating dynamic lateral stability and response and for estimating aerodynamic stability derivatives

    NASA Technical Reports Server (NTRS)

    Campbell, John P; Mckinney, Marion O

    1952-01-01

    A summary of methods for making dynamic lateral stability and response calculations and for estimating the aerodynamic stability derivatives required for use in these calculations is presented. The processes of performing calculations of the time histories of lateral motions, of the period and damping of these motions, and of the lateral stability boundaries are presented as a series of simple straightforward steps. Existing methods for estimating the stability derivatives are summarized and, in some cases, simple new empirical formulas are presented. Detailed estimation methods are presented for low-subsonic-speed conditions but only a brief discussion and a list of references are given for transonic and supersonic speed conditions.

  19. Estimation of Age Using Alveolar Bone Loss: Forensic and Anthropological Applications.

    PubMed

    Ruquet, Michel; Saliba-Serre, Bérengère; Tardivo, Delphine; Foti, Bruno

    2015-09-01

    The objective of this study was to utilize a new odontological methodological approach based on radiographic for age estimation. The study was comprised of 397 participants aged between 9 and 87 years. A clinical examination and a radiographic assessment of alveolar bone loss were performed. Direct measures of alveolar bone level were recorded using CT scans. A medical examination report was attached to the investigation file. Because of the link between alveolar bone loss and age, a model was proposed to enable simple, reliable, and quick age estimation. This work added new arguments for age estimation. This study aimed to develop a simple, standardized, and reproducible technique for age estimation of adults of actual populations in forensic medicine and ancient populations in funeral anthropology.

  20. Summary of Methods for Calculating Dynamic Lateral Stability and Response and for Estimating Lateral Stability Derivatives

    NASA Technical Reports Server (NTRS)

    Campbell, John P; Mckinney, Marion O

    1951-01-01

    A summary of methods for making dynamic lateral stability and response calculations and for estimating the aerodynamic stability derivatives required for use in these calculations is presented. The processes of performing calculations of the time histories of lateral motions, of the period and damping of these motions, and of the lateral stability boundaries are presented as a series of simple straightforward steps. Existing methods for estimating the stability derivatives are summarized and, in some cases, simple new empirical formulas are presented. Reference is also made to reports presenting experimental data that should be useful in making estimates of the derivatives. Detailed estimating methods are presented for low-subsonic-speed conditions but only a brief discussion and a list of references are given for transonic- and supersonic-speed conditions.

  1. Estimation of methane emission rate changes using age-defined waste in a landfill site.

    PubMed

    Ishii, Kazuei; Furuichi, Toru

    2013-09-01

    Long term methane emissions from landfill sites are often predicted by first-order decay (FOD) models, in which the default coefficients of the methane generation potential and the methane generation rate given by the Intergovernmental Panel on Climate Change (IPCC) are usually used. However, previous studies have demonstrated the large uncertainty in these coefficients because they are derived from a calibration procedure under ideal steady-state conditions, not actual landfill site conditions. In this study, the coefficients in the FOD model were estimated by a new approach to predict more precise long term methane generation by considering region-specific conditions. In the new approach, age-defined waste samples, which had been under the actual landfill site conditions, were collected in Hokkaido, Japan (in cold region), and the time series data on the age-defined waste sample's methane generation potential was used to estimate the coefficients in the FOD model. The degradation coefficients were 0.0501/y and 0.0621/y for paper and food waste, and the methane generation potentials were 214.4 mL/g-wet waste and 126.7 mL/g-wet waste for paper and food waste, respectively. These coefficients were compared with the default coefficients given by the IPCC. Although the degradation coefficient for food waste was smaller than the default value, the other coefficients were within the range of the default coefficients. With these new coefficients to calculate methane generation, the long term methane emissions from the landfill site was estimated at 1.35×10(4)m(3)-CH(4), which corresponds to approximately 2.53% of the total carbon dioxide emissions in the city (5.34×10(5)t-CO(2)/y).

  2. Dental age estimation based on third molar eruption in First Nation people of Canada.

    PubMed

    Schmeling, A; Olze, A; Pynn, B R; Kraul, V; Schulz, R; Heinecke, A; Pfeiffer, H

    2010-12-01

    Forensic age estimation of living subjects has become an increasing focus of interest in modern society. One main criterion for dental age estimation in the relevant age group is the evaluation of third molar eruption. The importance of ethnic variation in dental development requires population specific data for dental age evaluation. In the present study, we determined the stages of third molar eruption in 347 female and 258 male First Nations people of Canada aged 11 to 29 years based on radiological evidence from 605 conventional orthopantomograms. The results presented here provide data on the age of alveolar, gingival, and complete eruption of the third molars in the occlusal plane that can be used for forensic estimation of the minimum and most probable ages of investigated individuals.

  3. New Method of Age Estimation from Maxillary Sutures Closure in a Thai Population.

    PubMed

    Sinthubua, A; Theera-Umpon, N; Auephanwiriyakul, S; Ruengdit, S; Das, S; Mahakkanukrauh, P

    2016-01-01

    Age estimation is one of the major components of forensic identification. Cranial suture closure has long been used as indicator for age estimation. Maxillary sutures have been less studied for estimation of age at death because they vary in their timing of closure with age. The purpose of this study was to estimate age by examining 190 Thai skulls with age ranging between 15-93 years from Forensic Osteology Research Center, Faculty of Medicine, and Chiang Mai University. Four parts of maxillary suture (incisive, anterior, transverse, and posterior sutures) were investigated the suture obliteration of each suture by computerizing from photograph. The suture were measured by pixel counting.The prediction model which based on the support vector machine (SVM) for regression or support vector regression (SVR) was utilized for data analysis. The results showed high correlation (R2 = 0.9086) between the predicted age and actual age. Plot between actual age group and predicted age in seven groups also revealed high correlation (R2 = 0.9434). These can be implied that we are able to use this SVR model to predict age at death using maxillary suture information.The interesting issue is to further apply this model in more cases to ensure the generalization of the finding. This study is the first attempt to estimate age at death using a new method based on novel analysis which considers a characteristic of relationship between maxillary suture closures with age that are not in linear form. The present study may contribute as a basis knowledge and method for further study of age estimation in archaeological and forensic anthropological contexts, especially when only skull or base of skull are found. PMID:27212570

  4. Accuracy and precision of estimating age of gray wolves by tooth wear

    USGS Publications Warehouse

    Gipson, P.S.; Ballard, W.B.; Nowak, R.M.; Mech, L.D.

    2000-01-01

    We evaluated the accuracy and precision of tooth wear for aging gray wolves (Canis lupus) from Alaska, Minnesota, and Ontario based on 47 known-age or known-minimum-age skulls. Estimates of age using tooth wear and a commercial cementum annuli-aging service were useful for wolves up to 14 years old. The precision of estimates from cementum annuli was greater than estimates from tooth wear, but tooth wear estimates are more applicable in the field. We tended to overestimate age by 1-2 years and occasionally by 3 or 4 years. The commercial service aged young wolves with cementum annuli to within ?? 1 year of actual age, but under estimated ages of wolves ???9 years old by 1-3 years. No differences were detected in tooth wear patterns for wild wolves from Alaska, Minnesota, and Ontario, nor between captive and wild wolves. Tooth wear was not appropriate for aging wolves with an underbite that prevented normal wear or severely broken and missing teeth.

  5. [Forensic age estimation in juveniles and young adults: Reducing the range of scatter in age diagnosis by combining different methods].

    PubMed

    Schmidt, Sven; Schramm, Danilo; Ribbecke, Sebastian; Schulz, Ronald; Wittschieber, Daniel; Olze, Andreas; Vieth, Volker; Ramsthaler, H Frank; Pfischel, Klaus; Pfeiffer, Heidi; Geserick, Gunther; Schmeling, Andreas

    2016-01-01

    The dramatic rise in the number of refugees entering Germany means that age estimation for juveniles and young adults whose age is unclear but relevant to legal and official procedures has become more important than ever. Until now, whether and to what extent the combination of methods recommended by the Study Group on Forensic Age Diagnostics has resulted in a reduction of the range of scatter of the summarized age diagnosis has been unclear. Hand skeletal age, third molar mineralization stage and ossification stage of the medial clavicular epiphyses were determined for 307 individuals aged between 10 and 29 at time of death on whom autopsies were performed at the Institutes of Legal Medicine in Berlin, Frankfurt am Main and Hamburg between 2001 and 2011. To measure the range of scatter, linear regression analysis was used to calculate the standard error of estimate for each of the above methods individually and in combination. It was found that combining the above methods led to a reduction in the range of scatter. Due to various limitations of the study, the statistical parameters determined cannot, however, be used for age estimation practice. PMID:26934764

  6. The utility of near infrared spectroscopy for age estimation of deepwater sharks

    NASA Astrophysics Data System (ADS)

    Rigby, Cassandra L.; Wedding, Brett B.; Grauf, Steve; Simpfendorfer, Colin A.

    2014-12-01

    Reliable age information is vital for effective fisheries management, yet age determinations are absent for many deepwater sharks as they cannot be aged using traditional methods of growth bands counts. An alternative approach to ageing using near infrared spectroscopy (NIRS) was investigated using dorsal fin spines, vertebrae and fin clips of three species of deepwater sharks. Ages were successfully estimated for the two dogfish, Squalus megalops and Squalus montalbani, and NIRS spectra were correlated with body size in the catshark, Asymbolus pallidus. Correlations between estimated-ages of the dogfish dorsal fin spines and their NIRS spectra were good, with S. megalops R2=0.82 and S. montalbani R2=0.73. NIRS spectra from S. megalops vertebrae and fin clips that have no visible growth bands were correlated with estimated-ages, with R2=0.89 and 0.76, respectively. NIRS has the capacity to non-lethally estimate ages from fin spines and fin clips, and thus could significantly reduce the numbers of sharks that need to be lethally sampled for ageing studies. The detection of ageing materials by NIRS in poorly calcified deepwater shark vertebrae could potentially enable ageing of this group of sharks that are vulnerable to exploitation.

  7. A new method to estimate adult age-at-death using the acetabulum.

    PubMed

    Calce, Stephanie E

    2012-05-01

    Rissech et al. (J Forensic Sci 51 (2006) 213-229) described a method to estimate age-at-death of adult males using seven traits of the fused acetabulum. This study simplifies Rissech et al.'s technique and extends its application to adult females. Rissech et al.'s original scoring method was applied to a sample of 100 known-aged adults, three variables were selected based on stepwise multiple regression, and ages were collapsed into three broad ranges: young adult (17-39 years), middle adult (40-64 years), and old adult (65+ years). The revised method was applied to 249 new known-aged individuals from two other samples. To minimize observer bias, highlight the most critical traits, and encompass more age-related variation, unique digital renderings accompany morphological descriptions of age categories instead of photos. Three statistically significant characteristics highly correlated with age (P < 0.05) are capable of estimating age-at-death with 81% accuracy, both sexes combined. For misidentified individuals the tendency was to underestimate age. Results of both intraobserver error testing and inter-rater reliability demonstrated a moderate to substantial agreement in scoring between observers. When estimating the degree of development of features osteophyte development of the acetabular rim was the most inconsistent between observers. The revised acetabular method shows promise in estimating age for adults, particularly for those over the age of 65 years.

  8. Gene expression during blow fly development: improving the precision of age estimates in forensic entomology.

    PubMed

    Tarone, Aaron M; Foran, David R

    2011-01-01

    Forensic entomologists use size and developmental stage to estimate blow fly age, and from those, a postmortem interval. Since such estimates are generally accurate but often lack precision, particularly in the older developmental stages, alternative aging methods would be advantageous. Presented here is a means of incorporating developmentally regulated gene expression levels into traditional stage and size data, with a goal of more precisely estimating developmental age of immature Lucilia sericata. Generalized additive models of development showed improved statistical support compared to models that did not include gene expression data, resulting in an increase in estimate precision, especially for postfeeding third instars and pupae. The models were then used to make blind estimates of development for 86 immature L. sericata raised on rat carcasses. Overall, inclusion of gene expression data resulted in increased precision in aging blow flies.

  9. Accuracy of Four Dental Age Estimation Methods in Southern Indian Children

    PubMed Central

    Sanghvi, Praveen; Perumalla, Kiran Kumar; Srinivasaraju, D.; Srinivas, Jami; Kalyan, U. Siva; Rasool, SK. Md. Iftekhar

    2015-01-01

    Introduction: For various forensic investigations of both living and dead individuals, the knowledge of the actual age or date of birth of the subject is of utmost importance. In recent years, age estimation has gained importance for a variety of reasons, including identifying criminal and legal responsibility, and for many other social events such as birth certificate, marriage, beginning a job, joining the army and retirement. Developing teeth are used to assess maturity and estimate age in number of disciplines; however the accuracy of different methods has not been assessed systematically. The aim of this study was to determine the accuracy of four dental age estimation methods. Materials and Methods: Digital Orthopantomographs (OPGS) of South Indian children between the ages of 6 and 16 y who visited the department of Department of Oral medicine and Radiology of GITAM Dental College, Visakhapatnam, Andhra Pradesh, India with similar ethnic origin were assessed. Dental age was calculated using Demirjian, Willems, Nolla, and adopted Haavikko methods and the difference between estimated dental age and chronological age were compared with paired t-test and Wilcoxon signed rank test. Results: An overestimation of the dental age was observed by using Demirjian and Nolla methods (0.1±1.63, 0.47±0.83 years in total sample respectively) and an underestimation of dental age was observed by using Willems and Haavikko methods (-0.4±1.53, -2.9±1.41 years respectively in total sample). Conclusion: Nolla’s method was more accurate in estimating dental age compared to other methods. Moreover, all the four methods were found to be reliable in estimating age of individuals of unknown chronological age in South Indian children. PMID:25738008

  10. Heterogeneous Rates of Molecular Evolution and Diversification Could Explain the Triassic Age Estimate for Angiosperms.

    PubMed

    Beaulieu, Jeremy M; O'Meara, Brian C; Crane, Peter; Donoghue, Michael J

    2015-09-01

    Dating analyses based on molecular data imply that crown angiosperms existed in the Triassic, long before their undisputed appearance in the fossil record in the Early Cretaceous. Following a re-analysis of the age of angiosperms using updated sequences and fossil calibrations, we use a series of simulations to explore the possibility that the older age estimates are a consequence of (i) major shifts in the rate of sequence evolution near the base of the angiosperms and/or (ii) the representative taxon sampling strategy employed in such studies. We show that both of these factors do tend to yield substantially older age estimates. These analyses do not prove that younger age estimates based on the fossil record are correct, but they do suggest caution in accepting the older age estimates obtained using current relaxed-clock methods. Although we have focused here on the angiosperms, we suspect that these results will shed light on dating discrepancies in other major clades.

  11. Estimating survival rates with time series of standing age-structure data.

    PubMed

    Udevitz, Mark S; Gogan, Peter J P

    2012-04-01

    It has long been recognized that age-structure data contain useful information for assessing the status and dynamics of wildlife populations. For example, age-specific survival rates can be estimated with just a single sample from the age distribution of a stable, stationary population. For a population that is not stable, age-specific survival rates can be estimated using techniques such as inverse methods that combine time series of age-structure data with other demographic data. However, estimation of survival rates using these methods typically requires numerical optimization, a relatively long time series of data, and smoothing or other constraints to provide useful estimates. We developed general models for possibly unstable populations that combine time series of age-structure data with other demographic data to provide explicit maximum likelihood estimators of age-specific survival rates with as few as two years of data. As an example, we applied these methods to estimate survival rates for female bison (Bison bison) in Yellowstone National Park, USA. This approach provides a simple tool for monitoring survival rates based on age-structure data.

  12. Age estimation for shovelnose sturgeon: A cautionary note based on annulus formation in pectoral fin rays

    USGS Publications Warehouse

    Whiteman, K.W.; Travnichek, V.H.; Wildhaber, M.L.; DeLonay, A.; Papoulias, D.; Tillett, D.

    2004-01-01

    Numerous studies have examined the age and growth of shovelnose sturgeon Scaphirhynchus platorynchus, but only one study attempted to validate age estimation techniques. Therefore, our objective was to use marginal increment analysis to validate annulus formation in pectoral fin rays of shovelnose sturgeon collected from the Missouri River. We also compared the precision of age estimates between two different readers. Marginal increment distance indicated that for most of the populations an opaque band was laid down in pectoral fin rays during the summer. However, opaque bands were formed throughout the year in some individuals, which could be problematic when using fin rays for age estimation. The agreement of age estimates by two readers for shovelnose sturgeon was only 18%, and differences in ages between the two readers increased for older fish. The presence of split annuli, false annuli, spawning bands, imbedded rays, and deteriorating sections made individual growth rings difficult to separate. Our findings verified that opaque bands are formed annually during the summer in the pectoral fin rays of most shovelnose sturgeon, but some individuals form opaque bands during other times. Pectoral fin rays will probably continue to be the most practical method of age estimation in shovelnose sturgeon, but ages estimated by this method should be used with caution.

  13. Estimating survival rates with time series of standing age-structure data

    USGS Publications Warehouse

    Udevitz, Mark S.; Gogan, Peter J.

    2014-01-01

    It has long been recognized that age-structure data contain useful information for assessing the status and dynamics of wildlife populations. For example, age-specific survival rates can be estimated with just a single sample from the age distribution of a stable, stationary population. For a population that is not stable, age-specific survival rates can be estimated using techniques such as inverse methods that combine time series of age-structure data with other demographic data. However, estimation of survival rates using these methods typically requires numerical optimization, a relatively long time series of data, and smoothing or other constraints to provide useful estimates. We developed general models for possibly unstable populations that combine time series of age-structure data with other demographic data to provide explicit maximum likelihood estimators of age-specific survival rates with as few as two years of data. As an example, we applied these methods to estimate survival rates for female bison (Bison bison) in Yellowstone National Park, USA. This approach provides a simple tool for monitoring survival rates based on age-structure data.

  14. Estimating life expectancy using an age-cohort model in Taiwan.

    PubMed Central

    Lee, W C; Hsieh, R L

    1996-01-01

    OBJECTIVES: Life expectation is a valuable summary index in public health and actuarial science. The life expectancies published in the vital statistics, however, are derived from the "current" rather than from the "cohort" life table. The former is based on a strong assumption of constant mortality in the population, whereas the latter calls for a recording of the mortality experience of a group of individuals, which is often an impossible task. Thus, a method of calculating cohort life expectancy without actual follow up is much needed. METHODS: Estimation of cohort life expectancy was based on an age-cohort model. Mortality data for the male population in Taiwan from 1951 to 1990 are used to illustrate the methodology. RESULTS: The increment of life expectancy over time in Taiwan is actually steeper than was previously thought using the current life table technique. CONCLUSIONS: The method is easy to implement and the data required are the usual age and period cross classified mortality data. It warrants further investigation. PMID:8762391

  15. Cementum annulations, age estimation, and demographic dynamics in Mid-Holocene foragers of North India.

    PubMed

    Robbins Schug, G; Brandt, E T; Lukacs, J R

    2012-04-01

    One of the principal problems facing palaeodemography is age estimation in adult skeletons and the centrist tendency that affects many age estimation methods by artificially increasing the proportion of individuals in the 30-45-year age category. Several recent publications have indicated that cementum annulations are significantly correlated with known age of extraction or death. This study addresses the question of how demographic dynamics are altered for an archaeological sample when cementum-based age estimates are used as opposed to those obtained via conventional macroscopic methods. Age pyramids were constructed and demographic profiles were compared for the early Holocene skeletal population from Damdama (India). The results demonstrate that the use of cementum annulations for age estimation in only a subset of the skeletal sample has a significant impact on the demographic profile with regard to specific parameters such as mean age at death and life expectancy at birth. This confirms the importance of using cementum annulations to refine age estimates in archaeological samples, which, when combined with a fertility-centred approach to demography, can provide new insights into population dynamics in the past. PMID:22475664

  16. [Problems associated with chronological age estimation of children exploited in child pornography production].

    PubMed

    Bednarek, Jarosław

    2006-01-01

    Chronological age assessment of young persons featuring in pornographic pictures and videos is crucial to prove a violation of law. The paper discusses possibilities of and difficulties inherent in age estimation in cases of production and distribution of child pornography. The presented problems were divided into technical and individual development-associated issues. Technical difficulties included lack of a reference system for biological features reconstruction, poor quality and resolution of pictures or movies, pictures retouching and photomontage. The author stressed that biological hindrances in age assessment were the consequences of interpersonal variation of developmental patterns, namely overlapping of ranges typical for feature values at particular ages and biological variations between different human populations. The described problems can render age estimation impossible or far from precise. Developing more accurate methods of estimating age from pictures and videos requires the collaboration of specialists in the field of auxology, anthropology, pediatrics, as well as experts in photography and video techniques. PMID:17131758

  17. [Problems associated with chronological age estimation of children exploited in child pornography production].

    PubMed

    Bednarek, Jarosław

    2006-01-01

    Chronological age assessment of young persons featuring in pornographic pictures and videos is crucial to prove a violation of law. The paper discusses possibilities of and difficulties inherent in age estimation in cases of production and distribution of child pornography. The presented problems were divided into technical and individual development-associated issues. Technical difficulties included lack of a reference system for biological features reconstruction, poor quality and resolution of pictures or movies, pictures retouching and photomontage. The author stressed that biological hindrances in age assessment were the consequences of interpersonal variation of developmental patterns, namely overlapping of ranges typical for feature values at particular ages and biological variations between different human populations. The described problems can render age estimation impossible or far from precise. Developing more accurate methods of estimating age from pictures and videos requires the collaboration of specialists in the field of auxology, anthropology, pediatrics, as well as experts in photography and video techniques.

  18. Permeability estimation from log-derived porosity II. Via co-kriging

    SciTech Connect

    Fang, Jen Ho; Pu, Zhi Wei . Dept. of Geology)

    1993-03-01

    In paper (I) (given at this meeting), the authors applied fuzzy regression to the problem of permeability estimation from porosity-log data. In this paper, they introduce another novel approach, co-kriging. Co-kriging is a multivariate geostatistical technique designed for characterizing joint spatial correlations between pairs of variables (log-derived porosity vs. core-derived permeability in the context of this paper). In other words, co-kriging yields estimates that use not only the information from direct measurements of the variables being estimated, but also the information from measurements of a second variable. Thus, co-kriging can be used to predict permeability at uncored wells. This is a powerful technique because they usually have more log data than core data. By making use of co-kriging they can make good use of the log-derived porosity data. Results of the study using the data from Chunchula field illustrate the power of this technique.

  19. An evaluation of agreement between pectoral spines and otoliths for estimating ages of catfishes

    USGS Publications Warehouse

    Olive, J.A.; Schramm, Harold; Gerard, Patrick D.; Irwin, E.

    2011-01-01

    Otoliths have been shown to provide more accurate ages than pectoral spine sections for several catfish populations; but sampling otoliths requires euthanizing the specimen, whereas spines can be sampled non-lethally. To evaluate whether, and under what conditions, spines provide the same or similar age estimates as otoliths, we examined data sets of individual fish aged from pectoral spines and otoliths for six blue catfish Ictalurus furcatus populations (n=420), 14 channel catfish Ictalurus punctatus populations (n=997), and 10 flathead catfish Pylodictus olivaris populations (n=947) from lotic and lentic waters throughout the central and eastern U.S. Logistic regression determined that agreement between ages estimated from otoliths and spines was consistently related to age, but inconsistently related to growth rate. When modeled at mean growth rate, we found at least 80% probability of no difference in spine- and otolith-assigned ages up to ages 4 and 5 for blue and channel catfish, respectively. For flathead catfish, an 80% probability of agreement between spine- and otolith-assigned ages did not occur at any age due to high incidence of differences in assigned ages even for age-1 fish. Logistic regression models predicted at least 80% probability that spine and otolith ages differed by ≤1 year up to ages 13, 16, and 9 for blue, channel, and flathead catfish, respectively. Age-bias assessment found mean spine-assigned age differed by less than 1 year from otolith-assigned age up to ages 19, 9, and 17 for blue catfish, channel catfish, and flathead catfish, respectively. These results can be used to help guide decisions about which structure is most appropriate for estimating catfish ages for particular populations and management objectives.

  20. Estimating age of sea otters with cementum layers in the first premolar

    USGS Publications Warehouse

    Bodkin, J.L.; Ames, J.A.; Jameson, R.J.; Johnson, A.M.; Matson, G.M.

    1997-01-01

    We assessed sources of variation in the use of tooth cementum layers to determine age by comparing counts in premolar tooth sections to known ages of 20 sea otters (Enhydra lutris). Three readers examined each sample 3 times, and the 3 readings of each sample were averaged by reader to provide the mean estimated age. The mean (SE) of known age sample was 5.2 years (1.0) and the 3 mean estimated ages were 7.0 (1.0), 5.9 (1.1) and, 4.4 (0.8). The proportion of estimates accurate to within +/- 1 year were 0.25, 0.55, and 0.65 and to within +/- 2 years 0.65, 0.80, and 0.70, by reader. The proportions of samples estimated with >3 years error were 0.20, 0.10, and 0.05. Errors as large as 7, 6, and 5 years were made among readers. In few instances did all readers uniformly provide either accurate (error 1 yr) counts. In most cases (0.85), 1 or 2 of the readers provided accurate counts. Coefficients of determination (R2) between known ages and mean estimated ages were 0.81, 0.87, and 0.87, by reader. The results of this study suggest that cementum layers within sea otter premolar teeth likely are deposited annually and can be used for age estimation. However, criteria used in interpreting layers apparently varied by reader, occasionally resulting in large errors, which were not consistent among readers. While large errors were evident for some individual otters, there were no differences between the known and estimated age-class distribution generated by each reader. Until accuracy can be improved, application of this ageing technique should be limited to sample sizes of at least 6-7 individuals within age classes of >/=1 year.

  1. Age estimation in the living: Transition analysis on developing third molars.

    PubMed

    Tangmose, Sara; Thevissen, Patrick; Lynnerup, Niels; Willems, Guy; Boldsen, Jesper

    2015-12-01

    A radiographic assessment of third molar development is essential for differentiating between juveniles and adolescents in forensic age estimations. As the developmental stages of third molars are highly correlated, age estimates based on a combination of a full set of third molar scores are statistically complicated. Transition analysis (TA) is a statistical method developed for estimating age at death in skeletons, which combines several correlated developmental traits into one age estimate including a 95% prediction interval. The aim of this study was to evaluate the performance of TA in the living on a full set of third molar scores. A cross sectional sample of 854 panoramic radiographs, homogenously distributed by sex and age (15.0-24.0 years), were randomly split in two; a reference sample for obtaining age estimates including a 95% prediction interval according to TA; and a validation sample to test the age estimates against actual age. The mean inaccuracy of the age estimates was 1.82 years (±1.35) in males and 1.81 years (±1.44) in females. The mean bias was 0.55 years (±2.20) in males and 0.31 years (±2.30) in females. Of the actual ages, 93.7% of the males and 95.9% of the females (validation sample) fell within the 95% prediction interval. Moreover, at a sensitivity and specificity of 0.824 and 0.937 in males and 0.814 and 0.827 in females, TA performs well in differentiating between being a minor as opposed to an adult. Although accuracy does not outperform other methods, TA provides unbiased age estimates which minimize the risk of wrongly estimating minors as adults. Furthermore, when corrected ad hoc, TA produces appropriate prediction intervals. As TA allows expansion with additional traits, i.e. stages of development of the left hand-wrist and the clavicle, it has a great potential for future more accurate and reproducible age estimates, including an estimated probability of having attained the legal age limit of 18 years.

  2. Strategic Decision-Making Learning from Label Distributions: An Approach for Facial Age Estimation

    PubMed Central

    Zhao, Wei; Wang, Han

    2016-01-01

    Nowadays, label distribution learning is among the state-of-the-art methodologies in facial age estimation. It takes the age of each facial image instance as a label distribution with a series of age labels rather than the single chronological age label that is commonly used. However, this methodology is deficient in its simple decision-making criterion: the final predicted age is only selected at the one with maximum description degree. In many cases, different age labels may have very similar description degrees. Consequently, blindly deciding the estimated age by virtue of the highest description degree would miss or neglect other valuable age labels that may contribute a lot to the final predicted age. In this paper, we propose a strategic decision-making label distribution learning algorithm (SDM-LDL) with a series of strategies specialized for different types of age label distribution. Experimental results from the most popular aging face database, FG-NET, show the superiority and validity of all the proposed strategic decision-making learning algorithms over the existing label distribution learning and other single-label learning algorithms for facial age estimation. The inner properties of SDM-LDL are further explored with more advantages. PMID:27367691

  3. The accuracy of three methods of age estimation using radiographic measurements of developing teeth.

    PubMed

    Liversidge, H M; Lyons, F; Hector, M P

    2003-01-01

    The accuracy of age estimation using three quantitative methods of developing permanent teeth was investigated. These were Mörnstad et al. [Scand. J. Dent. Res. 102 (1994) 137], Liversidge and Molleson [J. For. Sci. 44 (1999) 917] and Carels et al. [J. Biol. Bucc. 19 (1991) 297]. The sample consisted of 145 white Caucasian children (75 girls, 70 boys) aged between 8 and 13 years. Tooth length and apex width of mandibular canine, premolars and first and second molars were measured from orthopantomographs using a digitiser. These data were substituted into equations from the three methods and estimated age was calculated and compared to chronological age. Age was under-estimated in boys and girls using all the three methods; the mean difference between chronological and estimated ages for method I was -0.83 (standard deviation +/-0.96) years for boys and -0.67 (+/-0.76) years for girls; method II -0.79 (+/-0.93) and -0.63 (+/-0.92); method III -1.03 (+/-1.48) and -1.35 (+/-1.11) for boys and girls, respectively. Further analysis of age cohorts, found the most accurate method to be method I for the age group 8.00-8.99 years where age could be predicted to 0.14+/-0.44 years (boys) and 0.10+/-0.32 years (girls). Accuracy was greater for younger children compared to older children and this decreased with age.

  4. How old am I? Age estimation in living adults: a case report.

    PubMed

    Cattaneo, C; De Angelis, D; Ruspa, M; Gibelli, D; Cameriere, R; Grandi, M

    2008-12-01

    Age estimation is a common task in forensic medicine. Odontologists are frequently involved in the age assessment of human remains or living juveniles. The need to estimate the age of living individuals is becoming more frequent, because of the increasing number of immigrants (illegal or otherwise) without acceptable identification documents and with missing or uncertain birth dates. Whereas age estimation in subadults is usually performed by methods based on the physiological growth of bones and teeth, in the case of living adults age determination is more difficult, because body maturation has come to an end and the most commonly used procedures in forensics on human remains are too invasive for the living individual. The following case report aims at highlighting the difficulties of performing age estimation in the living adult and the importance of a multidisciplinary approach including forensic odontology: a middle-aged woman from Ethiopia who was supposed to be 62 years old (according to one set of documents), was removed from employment lists as she had reached the retirement age for Italy. However another set of documents indicated a younger age (46 years). Hormonal dosage of E2 (17-β estradiol) and FSH (Follicle Stimulating Hormone) showed an age close to the begininng of menopause. An experimental dental method, based on the decrease of canine pulp chamber with age, was performed in order to obtain more information: the result was an estimation of a 47-57 age range. Combined results suggested that it was more likely that the actual age of the woman was closer to 46 than to 62.

  5. Comparison Of Quantitative Precipitation Estimates Derived From Rain Gauge And Radar Derived Algorithms For Operational Flash Flood Support.

    NASA Astrophysics Data System (ADS)

    Streubel, D. P.; Kodama, K.

    2014-12-01

    To provide continuous flash flood situational awareness and to better differentiate severity of ongoing individual precipitation events, the National Weather Service Research Distributed Hydrologic Model (RDHM) is being implemented over Hawaii and Alaska. In the implementation process of RDHM, three gridded precipitation analyses are used as forcing. The first analysis is a radar only precipitation estimate derived from WSR-88D digital hybrid reflectivity, a Z-R relationship and aggregated into an hourly ¼ HRAP grid. The second analysis is derived from a rain gauge network and interpolated into an hourly ¼ HRAP grid using PRISM climatology. The third analysis is derived from a rain gauge network where rain gauges are assigned static pre-determined weights to derive a uniform mean areal precipitation that is applied over a catchment on a ¼ HRAP grid. To assess the effect of different QPE analyses on the accuracy of RDHM simulations and to potentially identify a preferred analysis for operational use, each QPE was used to force RDHM to simulate stream flow for 20 USGS peak flow events. An evaluation of the RDHM simulations was focused on peak flow magnitude, peak flow timing, and event volume accuracy to be most relevant for operational use. Results showed RDHM simulations based on the observed rain gauge amounts were more accurate in simulating peak flow magnitude and event volume relative to the radar derived analysis. However this result was not consistent for all 20 events nor was it consistent for a few of the rainfall events where an annual peak flow was recorded at more than one USGS gage. Implications of this indicate that a more robust QPE forcing with the inclusion of uncertainty derived from the three analyses may provide a better input for simulating extreme peak flow events.

  6. Accuracy and sampling error of two age estimation techniques using rib histomorphometry on a modern sample.

    PubMed

    García-Donas, Julieta G; Dyke, Jeffrey; Paine, Robert R; Nathena, Despoina; Kranioti, Elena F

    2016-02-01

    Most age estimation methods are proven problematic when applied in highly fragmented skeletal remains. Rib histomorphometry is advantageous in such cases; yet it is vital to test and revise existing techniques particularly when used in legal settings (Crowder and Rosella, 2007). This study tested Stout & Paine (1992) and Stout et al. (1994) histological age estimation methods on a Modern Greek sample using different sampling sites. Six left 4th ribs of known age and sex were selected from a modern skeletal collection. Each rib was cut into three equal segments. Two thin sections were acquired from each segment. A total of 36 thin sections were prepared and analysed. Four variables (cortical area, intact and fragmented osteon density and osteon population density) were calculated for each section and age was estimated according to Stout & Paine (1992) and Stout et al. (1994). The results showed that both methods produced a systemic underestimation of the individuals (to a maximum of 43 years) although a general improvement in accuracy levels was observed when applying the Stout et al. (1994) formula. There is an increase of error rates with increasing age with the oldest individual showing extreme differences between real age and estimated age. Comparison of the different sampling sites showed small differences between the estimated ages suggesting that any fragment of the rib could be used without introducing significant error. Yet, a larger sample should be used to confirm these results.

  7. Age Estimation Based on Children's Voice: A Fuzzy-Based Decision Fusion Strategy

    PubMed Central

    Ting, Hua-Nong

    2014-01-01

    Automatic estimation of a speaker's age is a challenging research topic in the area of speech analysis. In this paper, a novel approach to estimate a speaker's age is presented. The method features a “divide and conquer” strategy wherein the speech data are divided into six groups based on the vowel classes. There are two reasons behind this strategy. First, reduction in the complicated distribution of the processing data improves the classifier's learning performance. Second, different vowel classes contain complementary information for age estimation. Mel-frequency cepstral coefficients are computed for each group and single layer feed-forward neural networks based on self-adaptive extreme learning machine are applied to the features to make a primary decision. Subsequently, fuzzy data fusion is employed to provide an overall decision by aggregating the classifier's outputs. The results are then compared with a number of state-of-the-art age estimation methods. Experiments conducted based on six age groups including children aged between 7 and 12 years revealed that fuzzy fusion of the classifier's outputs resulted in considerable improvement of up to 53.33% in age estimation accuracy. Moreover, the fuzzy fusion of decisions aggregated the complementary information of a speaker's age from various speech sources. PMID:25006595

  8. Accuracy and sampling error of two age estimation techniques using rib histomorphometry on a modern sample.

    PubMed

    García-Donas, Julieta G; Dyke, Jeffrey; Paine, Robert R; Nathena, Despoina; Kranioti, Elena F

    2016-02-01

    Most age estimation methods are proven problematic when applied in highly fragmented skeletal remains. Rib histomorphometry is advantageous in such cases; yet it is vital to test and revise existing techniques particularly when used in legal settings (Crowder and Rosella, 2007). This study tested Stout & Paine (1992) and Stout et al. (1994) histological age estimation methods on a Modern Greek sample using different sampling sites. Six left 4th ribs of known age and sex were selected from a modern skeletal collection. Each rib was cut into three equal segments. Two thin sections were acquired from each segment. A total of 36 thin sections were prepared and analysed. Four variables (cortical area, intact and fragmented osteon density and osteon population density) were calculated for each section and age was estimated according to Stout & Paine (1992) and Stout et al. (1994). The results showed that both methods produced a systemic underestimation of the individuals (to a maximum of 43 years) although a general improvement in accuracy levels was observed when applying the Stout et al. (1994) formula. There is an increase of error rates with increasing age with the oldest individual showing extreme differences between real age and estimated age. Comparison of the different sampling sites showed small differences between the estimated ages suggesting that any fragment of the rib could be used without introducing significant error. Yet, a larger sample should be used to confirm these results. PMID:26698389

  9. Dental age estimation of growing children by measurement of open apices: A Malaysian formula

    PubMed Central

    Cugati, Navaneetha; Kumaresan, Ramesh; Srinivasan, Balamanikanda; Karthikeyan, Priyadarshini

    2015-01-01

    Background: Age estimation is of prime importance in forensic science and clinical dentistry. Age estimation based on teeth development is one reliable approach. Many radiographic methods are proposed on the Western population for estimating dental age, and a similar assessment was found to be inadequate in Malaysian population. Hence, this study aims at formulating a regression model for dental age estimation in Malaysian children population using Cameriere's method. Materials and Methods: Orthopantomographs of 421 Malaysian children aged between 5 and 16 years involving all the three ethnic origins were digitalized and analyzed using Cameriere's method of age estimation. The subjects’ age was modeled as a function of the morphological variables, gender (g), ethnicity, sum of normalized open apices (s), number of tooth with completed root formation (N0) and the first-order interaction between s and N0. Results: The variables that contributed significantly to the fit were included in the regression model, yielding the following formula: Age = 11.368-0.345g + 0.553No -1.096s - 0.380s.No, where g is a variable, 1 for males and 2 for females. The equation explained 87.1% of total deviance. Conclusion: The results obtained insist on reframing the original Cameriere's formula to suit the population of the nation specifically. Further studies are to be conducted to evaluate the applicability of this formula on a larger sample size. PMID:26816464

  10. Skeletal age estimation in a contemporary Western Australian population using the Tanner-Whitehouse method.

    PubMed

    Maggio, Ariane; Flavel, Ambika; Hart, Rob; Franklin, Daniel

    2016-06-01

    Various age estimation techniques have been utilised in Australia to evaluate the age of individuals who do not have documentation to determine legal majority/culpability. These age estimation techniques rely on the assessment of skeletal development as visualised in radiographs, CT scans, MRI or ultrasound modalities, and subsequent comparison to reference standards. These standards are not always population specific and are thus known to be less accurate when applied outside of the original reference sample, leading to potential ethical implications. Therefore, the present study aims to: (i) explore the variation in developmental trajectories between the established Tanner-Whitehouse (TW) age estimation standards and a Western Australian population; and (ii) develop specific hand-wrist age estimation standards for the latter population. The present study examines digital anterior-posterior hand-wrist radiographs of 360 individuals 0 to 24.9 years of age, equally represented by sex. Each radiograph was assessed using the RUS, Carpal and 20-bone methods of Tanner et al. The standard error of the estimate (SEE) was calculated for each method (range: ♀ SEE ±0.4-11.5 years; ♂ SEE ±0.9-10.1 years). The most accurate method was TW3 RUS for females and the TW2 Carpal system for males. The 50th centile skeletal maturity scores for each year age group were plotted against average chronological age to produce polynomial regression standards with a demonstrated accuracy of (♀ SEE ±0.09-3.46 years; ♂ SEE ±0.02-3.42 years) for females and males, respectively. The standards presented here can be used in future forensic investigations that require age estimation of hand-wrist bones in a Western Australian population, however, they are not appropriate for establishing age of majority (18 years), as skeletal maturity was attained on average earlier than 15 years of age in both sexes for all three systems examined. PMID:27080619

  11. Radiological age estimation: based on third molar mineralization and eruption in Turkish children and young adults.

    PubMed

    Karadayi, Beytullah; Kaya, Ahsen; Kolusayın, Melek Ozlem; Karadayi, Sükriye; Afsin, Hüseyin; Ozaslan, Abdi

    2012-11-01

    Radiographic evaluation of mineralization and eruption stages of third molars using dental panoramic radiographies can be an efficient tool for chronological age estimation in both forensic sciences and legal medicine. The third molar tooth is utilized for dental age estimation about the age span of 15-23 years because it represents the only tooth still in development. The aim of this study is to obtain and analyze data regarding third molar development and eruption in Turkish population for dental age estimation. A total of 744 dental panoramic radiographies of 394 female and 350 male subjects aged between 8 and 22 years were examined. Third molar development was determined according to the Nolla classification system, and eruption was assessed relative to the alveolar bone level. Mandibular and maxillary third molars were generally found at similar stages of development on both sides. Nolla stage 6 (completed crown calcification) was reached at around the age of 15 in both maxillary and mandibular third molars in both sexes. Alveolar emergence was at around the age of 16 in males and around age of 17 in females. Although third molars' eruption shows greater variability than development of third molars, data which were obtained from this study about eruption of these teeth can be supportive to development data for age estimation.

  12. Dental age estimation from the developmental stage of the third molars in western Chinese population.

    PubMed

    Li, Guo; Ren, Jiayin; Zhao, Shuping; Liu, Yuanyuan; Li, Na; Wu, Wanhong; Yuan, Shanshan; Wang, Hu

    2012-06-10

    The purpose of this study is to provide reference data about estimating dental age from third molars of the western Chinese population for comparing with other populations and being applied to the age estimation of western Chinese juveniles and adolescents. A total of 2078 digital panoramic radiographs of 989 male and 1089 female Chinese subjects aged between 5 and 23 years were examined. The mineralization status of the third molars was assessed using the formation stages described by Demirjian et al. with two modifications. The results showed that the development of third molars in the western Chinese population was likely to begin at age 5 in both males and females. The third molars 28 and 48 showed significantly higher frequency in females than in males. The third molars 18 in the stage 1, 38 in the stages 1, A and G, and 48 in the stage H showed significantly older average age in females than in males. The Demirjian's stages C and D could be used as a reference stage to determine dichotomously whether a western Chinese is more likely to be under or above age 14 or 16, respectively. This study provided reference data for the age estimation of western Chinese juveniles and adolescents by the mineralization stages of the third molar. Apart from forensic age determination in living subjects, the presented reference data can also be used for age estimations of unidentified corpses and skeletons.

  13. Statistical methods to assess the reliability of measurements in the procedures for forensic age estimation.

    PubMed

    Ferrante, L; Cameriere, R

    2009-07-01

    In forensic science, anthropology, and archaeology, several techniques have been developed to estimate chronological age in both children and adults, using the relationship between age and morphological changes in the structure of teeth. Before implementing a statistical model to describe age as a function of the measured morphological variables, the reliability of the measurements of these variables must be evaluated using suitable statistical methods. This paper introduces some commonly used statistical methods for assessing the reliability of procedures for age estimation in the forensic field. The use of the concordance correlation coefficient and the intraclass correlation coefficient are explained. Finally, some pitfalls in the choice of the statistical methods to assess reliability of the measurements in age estimation are discussed.

  14. Dental Age Estimation: A Test of the Reliability of Correctly Identifying a Subject Over 18 Years of Age Using the Gold Standard of Chronological Age as the Comparator.

    PubMed

    Lucas, Victoria S; Andiappan, Manoharan; McDonald, Fraser; Roberts, Graham

    2016-09-01

    This study was designed to test the reliability of using the third molars to demarcate between child and adult status. A total of 2000 dental panoramic tomographs were used for assessment of the calculated age using the 8-stage system of tooth development and applied to all four third molars. The LL8 was also assessed using this 8-stage system. For each tooth development stage, the Normal distribution and percentile summary data were estimated. The calculated dental age compared with the chronological age was statistically significantly different (p < 0.001) for both females and males giving underestimates of the true age. Comparison of single tooth dental age and chronological age was only slightly different. The most important finding is that the assignment to above or below the 18-year threshold, in the age range 17 years to 19 years, could be wrong on up to 50% of occasions.

  15. Age estimation in children by measurement of open apices in teeth.

    PubMed

    Cameriere, Roberto; Ferrante, Luigi; Cingolani, Mariano

    2006-01-01

    This paper concerns a method for estimating the age of children based on their teeth. The sample consisted of 455 Italian white children (213 boys, 242 girls) aged between 5 and 15 years. The purpose of the present investigation was to present a method for assessing chronological age based on the relationship between age and measurement of the open apices in teeth. Pearson's correlation coefficients between age and these variables showed that the correlations between age and the open apices in teeth were significant and negative. Furthermore, gender and the number of teeth with the apical end of the root canals completely closed (N(0)) showed a significant correlation with chronological age. With the aid of a stepwise multiple regression model, a linear relationship between open apices, N(0), and age was shown. Statistical analysis indicated that these morphological variables explain 83.6% of the variations in estimated chronological age. The median of residual errors between the actual and estimated ages was -0.035 years [interquartile range (IQR)=1.18 years].

  16. Human Age Estimation Method Robust to Camera Sensor and/or Face Movement

    PubMed Central

    Nguyen, Dat Tien; Cho, So Ra; Pham, Tuyen Danh; Park, Kang Ryoung

    2015-01-01

    Human age can be employed in many useful real-life applications, such as customer service systems, automatic vending machines, entertainment, etc. In order to obtain age information, image-based age estimation systems have been developed using information from the human face. However, limitations exist for current age estimation systems because of the various factors of camera motion and optical blurring, facial expressions, gender, etc. Motion blurring can usually be presented on face images by the movement of the camera sensor and/or the movement of the face during image acquisition. Therefore, the facial feature in captured images can be transformed according to the amount of motion, which causes performance degradation of age estimation systems. In this paper, the problem caused by motion blurring is addressed and its solution is proposed in order to make age estimation systems robust to the effects of motion blurring. Experiment results show that our method is more efficient for enhancing age estimation performance compared with systems that do not employ our method. PMID:26334282

  17. Human Age Estimation Method Robust to Camera Sensor and/or Face Movement.

    PubMed

    Nguyen, Dat Tien; Cho, So Ra; Pham, Tuyen Danh; Park, Kang Ryoung

    2015-01-01

    Human age can be employed in many useful real-life applications, such as customer service systems, automatic vending machines, entertainment, etc. In order to obtain age information, image-based age estimation systems have been developed using information from the human face. However, limitations exist for current age estimation systems because of the various factors of camera motion and optical blurring, facial expressions, gender, etc. Motion blurring can usually be presented on face images by the movement of the camera sensor and/or the movement of the face during image acquisition. Therefore, the facial feature in captured images can be transformed according to the amount of motion, which causes performance degradation of age estimation systems. In this paper, the problem caused by motion blurring is addressed and its solution is proposed in order to make age estimation systems robust to the effects of motion blurring. Experiment results show that our method is more efficient for enhancing age estimation performance compared with systems that do not employ our method. PMID:26334282

  18. Interference of pregnancy steroid hormones with FPN test for estimation of phenothiazine derivatives in urine.

    PubMed

    Bastecký, J

    1975-01-01

    Interference of pregnancy steroid hormones with FPN test for estimation of some phenothiazine derivatives in urine has been investigated. The FPN test was positive in 97.9% of urine samples obtained from pregnant women. It is supposed that metabolites of estrogens and progestagens present in higher amounts in urine samples of these women are responsible for this positivity.

  19. Using a near-infrared spectrometer to estimate the age of Anopheles mosquitoes exposed to pyrethroids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We report on the accuracy of using near-infrared spectroscopy (NIRS) to predict the age of Anopheles mosquitoes reared from wild larvae and a mixed age-wild adult population collected from pit traps after exposure to pyrethroids. The mosquitoes reared from wild larvae were estimated as ,7 or $7 d ol...

  20. Comparison of rainbow smelt age estimates from fin rays and otoliths

    USGS Publications Warehouse

    Walsh, M.G.; Maloy, A.P.; O'Brien, T. P.

    2008-01-01

    Rainbow smelt Osmerus mordax, although nonnative, are an important component of the offshore food web in the Laurentian Great Lakes. In Lake Ontario, we estimate ages of rainbow smelt annually to study population dynamics such as year-class strength and age-specific growth and mortality. Since the early 1980s, we have used pectoral fin rays to estimate rainbow smelt ages, but the sectioning and mounting of fin rays are time and labor intensive. Our objective was to assess the feasibility of using otoliths rather than fin rays to estimate rainbow smelt ages. Three readers interpreted the ages of 172 rainbow smelt (60-198 mm total length) based on thin sections of pectoral fin rays, whole otoliths with no preparation, and whole otoliths that had been cleared for 1 month in a 70:30 ethanol : glycerin solution. Bias was lower and precision was greater for fin rays than for otoliths; these results were consistent for comparisons within readers (first and second readings by one individual; three readers were used) and between readers (one reading for each reader within a pair). Both otolith methods appeared to misclassify age-1 rainbow smelt. Fin ray ages had the highest precision and provided the best approximation of age estimates inferred from the Lake Ontario population's length frequency distribution and from our understanding of this population. ?? American Fisheries Society 2008.

  1. The measured and estimated rotary stability derivatives of the X-15 airplane

    NASA Technical Reports Server (NTRS)

    Tinling, Bruce; Surber, True; Tunnell, Phillips J; Lopez, Armando

    1958-01-01

    Measurements of the rotary derivatives of the X-15 aircraft were made in several of the wind tunnels of the National Advisory Committee for Aeronautics. The speed range was from landing speed up to Mach number, 3.5. The measurements were made on the steady-state, forced-oscillation equipment. The apparatus measures the rotary derivatives during small-amplitude, single-degree-of-freedom oscillations. In this paper the results of the wind-tunnel tests are compared with the values of the rotary derivatives estimated by the available procedures. Whenever possible, the results of wind-tunnel measurements of the static forces and moments on the X-15 have been utilized in the estimation procedures to obtain lift-curve slopes and centers of pressure of the tail surfaces. In this way, at least a partial account is taken of the effects of the fuselage and wing downwash and pressure field on the tail surfaces.

  2. Comparisons of Satellite Derived Precipitation Products with Multisensor Precipitation Estimation over Southeast United States

    NASA Astrophysics Data System (ADS)

    Prakash, O.; Curtis, D. C.; Parames, P. M.; Harris, D. J.

    2011-12-01

    Satellite-based precipitation estimates with high spatial and temporal resolution, large areal coverage and freely available global data provides a potential alternative source of precipitation data for areas where ground-based precipitation networks are sparse or nonexistent, particularly in the developing countries. This study compares three satellite-derived precipitation products (e.g., TMPA-V6, PERSIANN and CMORPH) and one radar-derived product (MPE data) for the time period from March 2009 to April 2009. We applied the Hovmöller diagrams approach to see the spatial and temporal patterns of the various satellite data products and to identify the storm events falling under the computation domain/basin. The zonal Hovmöller diagrams, a comparative analysis of the radar-derived rainfall rate with the satellite derived rainfall rate shows that the spatial and temporal patterns in the TMPA-V6 rainfall rate generally agree with the MPE rainfall rate. Moreover, the TMPA-V6 precipitation events match closely with MPE events, whereas the PERSIANN data are showing more storm events and magnitude than the MPE. However, in this case, CMORPH data products are estimating very poor storm patterns and magnitude. This study also compares mean areal precipitation (MAP) estimates derived from the above said four data sources and duration. ArcGIS tool was used to compute the MAP for every 3-hour duration over Apalachicola-Chattahoochee-Flint River Basin (ACF), United States. The analysis indicates that basin-wide mean area precipitation estimates from satellite-derived TMPA-V6 and PERSIANN data tend to under-estimate the rainfall throughout the two-month analysis. The peaking time trend of satellite data follows the trend of MPE data closely over ACF basin. The cumulative rainfall plots show that the PERSIANN data were less negatively biased than TRMM. However, on an event-by-event basis, satellite methods overestimated in some cases and in some cases underestimated

  3. Validation of an Algorithm to Estimate Gestational Age in Electronic Health Plan Databases

    PubMed Central

    Li, Qian; Andrade, Susan E.; Cooper, William O.; Davis, Robert L.; Dublin, Sascha; Hammad, Tarek A.; Pawloski, Pamala A.; Pinheiro, Simone P.; Raebel, Marsha A.; Scott, Pamela E.; Smith, David H.; Dashevsky, Inna; Haffenreffer, Katie; Johnson, Karin E.; Toh, Sengwee

    2013-01-01

    Purpose To validate an algorithm that uses delivery date and diagnosis codes to define gestational age at birth in electronic health plan databases. Methods Using data from 225,384 live born deliveries among women aged 15–45 years in 2001–2007 within 8 of the 11 health plans participating in the Medication Exposure in Pregnancy Risk Evaluation Program, we compared 1) the algorithm-derived gestational age versus the “gold-standard” gestational age obtained from the infant birth certificate files; and 2) the prenatal exposure status of two antidepressants (fluoxetine and sertraline) and two antibiotics (amoxicillin and azithromycin) as determined by the algorithm-derived versus the gold-standard gestational age. Results The mean algorithm-derived gestational age at birth was lower than the mean obtained from the birth certificate files among singleton deliveries (267.9 versus 273.5 days) but not among multiple-gestation deliveries (253.9 versus 252.6 days). The algorithm-derived prenatal exposure to the antidepressants had a sensitivity and a positive predictive value (PPV) of ≥95%, and a specificity and a negative predictive value (NPV) of almost 100%. Sensitivity and PPV were both ≥90%, and specificity and NPV were both >99% for the antibiotics. Conclusions A gestational age algorithm based upon electronic health plan data correctly classified medication exposure status in most live born deliveries, but misclassification may be higher for drugs typically used for short durations. PMID:23335117

  4. Estimating age from recapture data: Integrating incremental growth measures with ancillary data to infer age-at-length

    USGS Publications Warehouse

    Eaton, Mitchell J.; Link, William A.

    2011-01-01

    Estimating the age of individuals in wild populations can be of fundamental importance for answering ecological questions, modeling population demographics, and managing exploited or threatened species. Significant effort has been devoted to determining age through the use of growth annuli, secondary physical characteristics related to age, and growth models. Many species, however, either do not exhibit physical characteristics useful for independent age validation or are too rare to justify sacrificing a large number of individuals to establish the relationship between size and age. Length-at-age models are well represented in the fisheries and other wildlife management literature. Many of these models overlook variation in growth rates of individuals and consider growth parameters as population parameters. More recent models have taken advantage of hierarchical structuring of parameters and Bayesian inference methods to allow for variation among individuals as functions of environmental covariates or individual-specific random effects. Here, we describe hierarchical models in which growth curves vary as individual-specific stochastic processes, and we show how these models can be fit using capture–recapture data for animals of unknown age along with data for animals of known age. We combine these independent data sources in a Bayesian analysis, distinguishing natural variation (among and within individuals) from measurement error. We illustrate using data for African dwarf crocodiles, comparing von Bertalanffy and logistic growth models. The analysis provides the means of predicting crocodile age, given a single measurement of head length. The von Bertalanffy was much better supported than the logistic growth model and predicted that dwarf crocodiles grow from 19.4 cm total length at birth to 32.9 cm in the first year and 45.3 cm by the end of their second year. Based on the minimum size of females observed with hatchlings, reproductive maturity was estimated

  5. Estimating age from recapture data: Integrating incremental growth measures with ancillary data to infer age-at-length

    USGS Publications Warehouse

    Eaton, M.J.; Link, W.A.

    2011-01-01

    Estimating the age of individuals in wild populations can be of fundamental importance for answering ecological questions, modeling population demographics, and managing exploited or threatened species. Significant effort has been devoted to determining age through the use of growth annuli, secondary physical characteristics related to age, and growth models. Many species, however, either do not exhibit physical characteristics useful for independent age validation or are too rare to justify sacrificing a large number of individuals to establish the relationship between size and age. Length-at-age models are well represented in the fisheries and other wildlife management literature. Many of these models overlook variation in growth rates of individuals and consider growth parameters as population parameters. More recent models have taken advantage of hierarchical structuring of parameters and Bayesian inference methods to allow for variation among individuals as functions of environmental covariates or individual-specific random effects. Here, we describe hierarchical models in which growth curves vary as individual-specific stochastic processes, and we show how these models can be fit using capture-recapture data for animals of unknown age along with data for animals of known age. We combine these independent data sources in a Bayesian analysis, distinguishing natural variation (among and within individuals) from measurement error. We illustrate using data for African dwarf crocodiles, comparing von Bertalanffy and logistic growth models. The analysis provides the means of predicting crocodile age, given a single measurement of head length. The von Bertalanffy was much better supported than the logistic growth model and predicted that dwarf crocodiles grow from 19.4 cm total length at birth to 32.9 cm in the first year and 45.3 cm by the end of their second year. Based on the minimum size of females observed with hatchlings, reproductive maturity was estimated to

  6. Effective number of breeding adults in Bufo bufo estimated from age-specific variation at minisatellite loci

    USGS Publications Warehouse

    Scribner, K.T.; Arntzen, J.W.; Burke, T.

    1997-01-01

    Estimates of the effective number of breeding adults were derived for three semi-isolated populations of the common toad Bufo bufo based on temporal (i.e. adult-progeny) variance in allele frequency for three highly polymorphic minisatellite loci. Estimates of spatial variance in allele frequency among populations and of age-specific measures of genetic variability are also described. Each population was characterized by a low effective adult breeding number (N(b)) based on a large age-specific variance in minisatellite allele frequency. Estimates of N(b) (range 21-46 for population means across three loci) were ??? 55-230-fold lower than estimates of total adult census size. The implications of low effective breeding numbers for long-term maintenance of genetic variability and population viability are discussed relative to the species' reproductive ecology, current land-use practices, and present and historical habitat modification and loss. The utility of indirect measures of population parameters such as N(b) and N(e) based on time-series data of minisatellite allele frequencies is discussed relative to similar measures estimated from commonly used genetic markers such as protein allozymes.

  7. The Ages of A-Stars. I. Interferometric Observations and Age Estimates for Stars in the Ursa Major Moving Group

    NASA Astrophysics Data System (ADS)

    Jones, Jeremy; White, R. J.; Boyajian, T.; Schaefer, G.; Baines, E.; Ireland, M.; Patience, J.; ten Brummelaar, T.; McAlister, H.; Ridgway, S. T.; Sturmann, J.; Sturmann, L.; Turner, N.; Farrington, C.; Goldfinger, P. J.

    2015-11-01

    We have observed and spatially resolved a set of seven A-type stars in the nearby Ursa Major moving group with the Classic, CLIMB, and PAVO beam combiners on the Center for High Angular Resolution Astronomy Array. At least four of these stars have large rotational velocities (v{sin}i ≳ 170 {km} {{{s}}}-1) and are expected to be oblate. These interferometric measurements, the stars’ observed photometric energy distributions, and v{sin}i values are used to computationally construct model oblate stars from which stellar properties (inclination, rotational velocity, and the radius and effective temperature as a function of latitude, etc.) are determined. The results are compared with MESA stellar evolution models to determine masses and ages. The value of this new technique is that it enables the estimation of the fundamental properties of rapidly rotating stars without the need to fully image the star. It can thus be applied to stars with sizes comparable to the interferometric resolution limit as opposed to those that are several times larger than the limit. Under the assumption of coevality, the spread in ages can be used as a test of both the prescription presented here and the MESA evolutionary code for rapidly rotating stars. With our validated technique, we combine these age estimates and determine the age of the moving group to be 414 ± 23 Myr, which is consistent with, but much more precise than previous estimates.

  8. Use of soil catena field data for estimating relative ages of moraines

    SciTech Connect

    Birkeland, P.W.; Berry, M.E. ); Swanson, D.K. )

    1991-03-01

    Soils at the crests of moraines are commonly used to estimate the relative ages of moraines. However, for various pedologic and geomorphic reasons, soil development at crest sites may not truly reflect the time since moraine formation; for example, some crest soils on moraines of greatly different age are similar in morphology and development. Soil catena data for soils at several sites aligned downslope from the crest can greatly improve on the usefulness of soil data for estimating moraine ages. For this purpose, the authors use the weighted mean catena profile development index, which condenses field data for all of the soils in each catena into a single value.

  9. Estimating Small-area Populations by Age and Sex Using Spatial Interpolation and Statistical Inference Methods

    SciTech Connect

    Qai, Qiang; Rushton, Gerald; Bhaduri, Budhendra L; Bright, Eddie A; Coleman, Phil R

    2006-01-01

    The objective of this research is to compute population estimates by age and sex for small areas whose boundaries are different from those for which the population counts were made. In our approach, population surfaces and age-sex proportion surfaces are separately estimated. Age-sex population estimates for small areas and their confidence intervals are then computed using a binomial model with the two surfaces as inputs. The approach was implemented for Iowa using a 90 m resolution population grid (LandScan USA) and U.S. Census 2000 population. Three spatial interpolation methods, the areal weighting (AW) method, the ordinary kriging (OK) method, and a modification of the pycnophylactic method, were used on Census Tract populations to estimate the age-sex proportion surfaces. To verify the model, age-sex population estimates were computed for paired Block Groups that straddled Census Tracts and therefore were spatially misaligned with them. The pycnophylactic method and the OK method were more accurate than the AW method. The approach is general and can be used to estimate subgroup-count types of variables from information in existing administrative areas for custom-defined areas used as the spatial basis of support in other applications.

  10. Age estimation using lower permanent first molars on a panoramic radiograph: A digital image analysis

    PubMed Central

    Talabani, Ranjdar M.; Baban, Mohammed T.; Mahmood, Mohammed A.

    2015-01-01

    Objective: A study was carried out to analyze the efficacy and practical application for age estimation using digital panoramic radiograph to exploit image analysis to obtain metric measurement of morphological parameters of permanent mandibular first molar on Sulaimani population. Materials and Methods: In the present study a population of known age and sex was studied and subjected to digital panoramic radiographic examination. The correlation between the reduction of coronal pulp cavity and chronological age was examined in a sample of 96 individuals distributed into four age groups: 20-29 years (29 cases), 30-39 years (29 cases), 40-49 years (26 cases) and 50-59 years (12 cases). The height (mm) of the crown (CH = coronal height) and the height (mm) of coronal pulp cavity (CPCH = coronal pulp cavity height) of 96 of first molars from all subjects was measured. The tooth–coronal index (TCI) after Ikeda et al. was computed for each tooth and regressed on real age. Results: ANOVA was used to show the strength of relation between the age and TCI (P = 0.0000). The correlation coefficient (r2) was 0.49, which mean there is strong negative linear regression between age and TCI with the r2, regarding predicting age using TCI value, after the following equation calculated, Predicted age = 3.78 – (0.064 TCI) showed that there is no significant difference between real age and estimated age. Conclusion: There is a strong negative liner relationship between TCIs of mandibular first molars with chronological age of Sulaimani population, and age of individuals can therefore be estimated with a good degree of accuracy using regression equations. PMID:26005307

  11. The Potential of Chitosan and Its Derivatives in Prevention and Treatment of Age-Related Diseases

    PubMed Central

    Kerch, Garry

    2015-01-01

    Age-related, diet-related and protein conformational diseases, such as atherosclerosis, diabetes mellitus, cancer, hypercholesterolemia, cardiovascular and neurodegenerative diseases are common in the elderly population. The potential of chitosan, chitooligosaccharides and their derivatives in prevention and treatment of age-related dysfunctions is reviewed and discussed in this paper. The influence of oxidative stress, low density lipoprotein oxidation, increase of tissue stiffness, protein conformational changes, aging-associated chronic inflammation and their pathobiological significance have been considered. The chitosan-based functional food also has been reviewed. PMID:25871293

  12. The potential of chitosan and its derivatives in prevention and treatment of age-related diseases.

    PubMed

    Kerch, Garry

    2015-04-01

    Age-related, diet-related and protein conformational diseases, such as atherosclerosis, diabetes mellitus, cancer, hypercholesterolemia, cardiovascular and neurodegenerative diseases are common in the elderly population. The potential of chitosan, chitooligosaccharides and their derivatives in prevention and treatment of age-related dysfunctions is reviewed and discussed in this paper. The influence of oxidative stress, low density lipoprotein oxidation, increase of tissue stiffness, protein conformational changes, aging-associated chronic inflammation and their pathobiological significance have been considered. The chitosan-based functional food also has been reviewed.

  13. Derivation of safety factors for setting harvest quotas on adult walleyes from past estimates of abundance

    USGS Publications Warehouse

    Hansen, Michael J.; Staggs, Michael D.; Hoff, Michael H.

    1991-01-01

    Past population estimates of adult walleyes Stizostedion vitreum can be used to set harvest quotas, provided that temporal variability in abundance of adult walleyes is accounted for. We used a long-term data set from Escanaba Lake, Wisconsin, to evaluate the accuracy of past population estimates for setting current-year quotas for adult walleyes. The results from Escanaba Lake were corroborated by comparison with other lakes where adult walleye abundance was estimated in more than 1 year. The accuracy of estimates of adult walleye abundance declined over time from the year the estimate was obtained to the year it was used to set a harvest quota. We derived safety factors for application to past estimates of population size; these factors limit the occurrence of an exploitation rate exceeding the maximum sustainable rate (35%) to approximately 1 in 40. These safety factors declined from 35% for 1-year-old estimates to less than 20% for 10-year-old estimates.

  14. Aging impairs peritoneal but not bone marrow-derived macrophage phagocytosis.

    PubMed

    Linehan, Eimear; Dombrowski, Yvonne; Snoddy, Rachel; Fallon, Padraic G; Kissenpfennig, Adrien; Fitzgerald, Denise C

    2014-08-01

    Aging results in deterioration of the immune system, which is associated with increased susceptibility to infection and impaired wound healing in the elderly. Phagocytosis is an essential process in both wound healing and immune defence. As such, age-related impairments in phagocytosis impact on the health of the elderly population. Phagocytic efficiency in peritoneal macrophages, bone marrow-derived macrophages and bone marrow monocytes from young and old mice was investigated. Aging significantly impaired phagocytosis by peritoneal macrophages, both in vitro and in vivo. However, bone marrow-derived macrophages and bone marrow monocytes did not exhibit age-related impairments in phagocytosis, suggesting no intrinsic defect in these cells. We sought to investigate underlying mechanisms in age-related impairments in phagocytosis by peritoneal macrophages. We hypothesized that microenvironmental factors in the peritoneum of old mice impaired macrophage phagocytosis. Indeed, macrophages from young mice injected into the peritoneum of old mice exhibited impaired phagocytosis. Proportions of peritoneal immune cells were characterized, and striking increases in numbers of T cells, B1 and B2 cells were observed in the peritoneum of old mice compared with young mice. In addition, B cell-derived IL-10 was increased in resting and LPS-activated peritoneal cell cultures from old mice. These data demonstrate that aging impairs phagocytosis by tissue-resident peritoneal macrophages, but not by bone marrow-derived macrophages/monocytes, and suggest that age-related defects in macrophage phagocytosis may be due to extrinsic factors in the tissue microenvironment. As such, defects may be reversible and macrophages could be targeted therapeutically in order to boost immune function in the elderly.

  15. Estimation of muscle activity using higher-order derivatives, static optimization, and forward-inverse dynamics.

    PubMed

    Yamasaki, Taiga; Idehara, Katsutoshi; Xin, Xin

    2016-07-01

    We propose a new method to estimate muscle activity in a straightforward manner with high accuracy and relatively small computational costs by using the external input of the joint angle and its first to fourth derivatives with respect to time. The method solves the inverse dynamics problem of the skeletal system, the forward dynamics problem of the muscular system, and the load-sharing problem of muscles as a static optimization of neural excitation signals. The external input including the higher-order derivatives is required for a calculation of constraints imposed on the load-sharing problem. The feasibility of the method is demonstrated by the simulation of a simple musculoskeletal model with a single joint. Moreover, the influences of the muscular dynamics, and the higher-order derivatives on the estimation of the muscle activity are demonstrated, showing the results when the time constants of the activation dynamics are very small, and the third and fourth derivatives of the external input are ignored, respectively. It is concluded that the method can have the potential to improve estimation accuracy of muscle activity of highly dynamic motions. PMID:27211782

  16. Age estimation by pulp/tooth ratio in canines by peri-apical X-rays.

    PubMed

    Cameriere, Roberto; Ferrante, Luigi; Belcastro, Maria Giovanna; Bonfiglioli, Benedetta; Rastelli, Elisa; Cingolani, Mariano

    2007-01-01

    Estimation of age in individuals has received considerable attention in forensic science, in which it is a widely used method for individual identification, together with paleo-demographic analyses to establish mortality patterns in past populations. The present investigation, which is a continuation of a previously published pilot study, was conducted to examine the possible application of the pulp/tooth area ratio by peri-apical images as an indicator of age at death. A total of 200 peri-apical X-rays of upper and lower canines were assembled from 57 male and 43 female skeletons of Caucasian origin, aged between 20 and 79 years. They belong to the Frassetto osteological collection of Sassari (Sardinia) and are housed in the Museum of Anthropology, Department of Experimental and Evolutionistic Biology, University of Bologna. For each skeleton, dental maturity was evaluated by measuring the pulp/tooth area ratio on upper (x(1)) and lower (x(2)) canines. Very good agreement was found between intraobserver measurements. Statistical analysis was performed in order to obtain multiple regression formulae for dental age calculation, with chronological age as dependent variable, and gender, and upper and lower canines as independent variables. Stepwise regression analysis showed that gender did not contribute significantly to the fit (p=0.881) whereas variables x(1) and x(2) and the first-order interaction between them did. These two variables explained 92.5% of variations in estimated chronological age and the residual standard error was 4.06 years. Lastly, two simple linear regression equations were obtained for age estimation using canines from the maxilla and mandible separately. Both models explained 86% of variations in estimated chronological age and allowed an age-at-death estimate with a residual standard error of about 5.4 years.

  17. Error Estimates Derived from the Data for Least-Squares Spline Fitting

    SciTech Connect

    Jerome Blair

    2007-06-25

    The use of least-squares fitting by cubic splines for the purpose of noise reduction in measured data is studied. Splines with variable mesh size are considered. The error, the difference between the input signal and its estimate, is divided into two sources: the R-error, which depends only on the noise and increases with decreasing mesh size, and the Ferror, which depends only on the signal and decreases with decreasing mesh size. The estimation of both errors as a function of time is demonstrated. The R-error estimation requires knowledge of the statistics of the noise and uses well-known methods. The primary contribution of the paper is a method for estimating the F-error that requires no prior knowledge of the signal except that it has four derivatives. It is calculated from the difference between two different spline fits to the data and is illustrated with Monte Carlo simulations and with an example.

  18. The derivation of estimated dust exposures for U. S. coal miners working before 1970

    SciTech Connect

    Attfield, M.D.; Morring, K. )

    1992-04-01

    A number of reports on the prevalence of coal workers' pneumoconiosis in U.S. coal miners have been published, yet very little is known about the relationship between dust exposure and pneumoconiosis levels in the U.S. This report describes the derivation of cumulative dust exposure estimates by back-extrapolation of data processed by the Mine Safety and Health Administration after 1970 by using a ratio of dust concentrations based on information collected during environmental surveys at certain U.S. mines by the Bureau of Mines between 1968 and 1969. Cumulative personal dust exposure estimates were calculated by using occupational histories obtained from the miners and job-specific estimates of dust concentration. In other reports, the resulting estimated exposures have been shown to correlate well with various measures of respiratory morbidity.

  19. The use of neural networks in identifying error sources in satellite-derived tropical SST estimates.

    PubMed

    Lee, Yung-Hsiang; Ho, Chung-Ru; Su, Feng-Chun; Kuo, Nan-Jung; Cheng, Yu-Hsin

    2011-01-01

    An neural network model of data mining is used to identify error sources in satellite-derived tropical sea surface temperature (SST) estimates from thermal infrared sensors onboard the Geostationary Operational Environmental Satellite (GOES). By using the Back Propagation Network (BPN) algorithm, it is found that air temperature, relative humidity, and wind speed variation are the major factors causing the errors of GOES SST products in the tropical Pacific. The accuracy of SST estimates is also improved by the model. The root mean square error (RMSE) for the daily SST estimate is reduced from 0.58 K to 0.38 K and mean absolute percentage error (MAPE) is 1.03%. For the hourly mean SST estimate, its RMSE is also reduced from 0.66 K to 0.44 K and the MAPE is 1.3%.

  20. Forensic age estimation through evaluation of the apophyseal ossification of the iliac crest in Western Chinese.

    PubMed

    Zhang, Kui; Dong, Xiao-ai; Chen, Xiao-gang; Li, Yuan; Deng, Zhen-hua

    2015-07-01

    The criminal age estimation procedures have gained greatest significance to date, a reliable age diagnostics may depend on data of skeletal maturation from different socioeconomic status. In order to establish the iliac crest apophysis as a possible criterion for forensic age estimation in a different socioeconomic status, and to examine the pace of ossification for the iliac crest apophysis in Western Chinese, one thousand seven hundreds and seventy-seven conventional pelvic radiographs relating to West China Han group routinely taken between January 2010 and June 2012 have been sighted. The data was analysed with separation of the sexes. The results indicated that stage 2a was last observed in females at the age of 17.00 and in males at the age of 18.01, stage 3a was first achieved in females at the age of 14.46 and in males at the age of 15.31, stage 4 was observed between 17.95 and 25.98 years for male and between 18.36 and 25.95 years for female. By comparison with previous studies, our research indicated that Western Chinese presents a delaying development for the iliac crest apophysis. Furthermore, the present study with eight stages of ossification for the iliac crest offers a valuable alternative method of estimation of 18 years of age for Western Chinese.

  1. A Novel Objective Method of Estimating the Age of Mandibles from African Elephants (Loxodonta africana Africana)

    PubMed Central

    Stansfield, Fiona J.

    2015-01-01

    The importance of assigning an accurate estimate of age and sex to elephant carcasses found in the wild has increased in recent years with the escalation in levels of poaching throughout Africa. Irregularities identified in current ageing techniques prompted the development of a new method to describe molar progression throughout life. Elephant mandibles (n = 323) were studied and a point near the distal dental alveolus was identified as being most useful in ranking each jaw according to molar progression. These ‘Age Reference Lines’ were then associated with an age scale based on previous studies and Zimbabwean mandibles of known age. The new ranking produced a single age scale that proved useful for both male and female mandibles up to the maximum lifespan age of 70–75 years. Methods to aid in molar identification and the sexing of found jaws were also identified. PMID:25970428

  2. A Novel Objective Method of Estimating the Age of Mandibles from African Elephants (Loxodonta africana Africana).

    PubMed

    Stansfield, Fiona J

    2015-01-01

    The importance of assigning an accurate estimate of age and sex to elephant carcasses found in the wild has increased in recent years with the escalation in levels of poaching throughout Africa. Irregularities identified in current ageing techniques prompted the development of a new method to describe molar progression throughout life. Elephant mandibles (n = 323) were studied and a point near the distal dental alveolus was identified as being most useful in ranking each jaw according to molar progression. These 'Age Reference Lines' were then associated with an age scale based on previous studies and Zimbabwean mandibles of known age. The new ranking produced a single age scale that proved useful for both male and female mandibles up to the maximum lifespan age of 70-75 years. Methods to aid in molar identification and the sexing of found jaws were also identified.

  3. A Novel Objective Method of Estimating the Age of Mandibles from African Elephants (Loxodonta africana Africana).

    PubMed

    Stansfield, Fiona J

    2015-01-01

    The importance of assigning an accurate estimate of age and sex to elephant carcasses found in the wild has increased in recent years with the escalation in levels of poaching throughout Africa. Irregularities identified in current ageing techniques prompted the development of a new method to describe molar progression throughout life. Elephant mandibles (n = 323) were studied and a point near the distal dental alveolus was identified as being most useful in ranking each jaw according to molar progression. These 'Age Reference Lines' were then associated with an age scale based on previous studies and Zimbabwean mandibles of known age. The new ranking produced a single age scale that proved useful for both male and female mandibles up to the maximum lifespan age of 70-75 years. Methods to aid in molar identification and the sexing of found jaws were also identified. PMID:25970428

  4. Paleoglaciation of the Tibetan Plateau based on exposure ages and ELA depression estimates

    NASA Astrophysics Data System (ADS)

    Heyman, Jakob

    2014-05-01

    The Tibetan Plateau holds a major part of all glaciers outside the polar regions and an ample record of past glaciations. The glacial history of the Tibetan Plateau has attracted significant interest, with a large body of research investigating the extent, timing, and climatic implications of past glaciations. Here I present an extensive compilation of exposure ages and equilibrium line altitude (ELA) depression estimates from glacial deposits across the Tibetan Plateau to address the timing and degree of past glaciations. I compiled Be-10 exposure age data for a total of 1877 samples and recalculated exposure ages using an updated (lower) global Be-10 production rate. All samples were organized in groups of individual glacial deposits where each deposit represents one glacial event enabling evaluation of the exposure age clustering. For each glacial deposit I estimated the ELA depression based on a simple toe to headwall ratio approach using Google Earth. To discriminate good (well-clustered) from poor (scattered) exposure age groups the glacial deposits were divided into three groups based on exposure age clustering. A major part of the glacial deposits have scattered exposure ages affected by prior or incomplete exposure, complicating exposure age interpretations. The well-clustered exposure age groups are primarily from mountain ranges along the margins of the Tibetan Plateau with a main peak in age between 10 and 30 ka, indicating glacial advances during the global last glacial maximum (LGM). A large number of exposure ages older than 30 ka indicates maximum glaciation predating the LGM, but the exposure age scatter generally prohibits accurate definition of the glacial chronology. The ELA depression estimates scatter significantly, but a major part is remarkably low. Average ELA depressions of 333 ± 191 m for the LGM and 494 ± 280 m for the pre-LGM exposure indicate restricted glacier expansion and limited glacial cooling.

  5. Donor age negatively impacts adipose tissue-derived mesenchymal stem cell expansion and differentiation

    PubMed Central

    2014-01-01

    Background Human adipose tissue is an ideal autologous source of mesenchymal stem cells (MSCs) for various regenerative medicine and tissue engineering strategies. Aged patients are one of the primary target populations for many promising applications. It has long been known that advanced age is negatively correlated with an organism’s reparative and regenerative potential, but little and conflicting information is available about the effects of age on the quality of human adipose tissue derived MSCs (hAT-MSCs). Methods To study the influence of age, the expansion and in vitro differentiation potential of hAT-MSCs from young (<30 years), adult (35-50 years) and aged (>60 years) individuals were investigated. MSCs were characterized for expression of the genes p16INK4a and p21 along with measurements of population doublings (PD), superoxide dismutase (SOD) activity, cellular senescence and differentiation potential. Results Aged MSCs displayed senescent features when compared with cells isolated from young donors, concomitant with reduced viability and proliferation. These features were also associated with significantly reduced differentiation potential in aged MSCs compared to young MSCs. Conclusions In conclusion, advancing age negatively impacts stem cell function and such age related alterations may be detrimental for successful stem cell therapies. PMID:24397850

  6. Letter report: Population estimates by age, sex and race for 10-county study area

    SciTech Connect

    Pittenger, D B

    1992-02-01

    The Hanford Environmental Does Reconstruction (HEDR) Project was established to estimate radiation doses that people could have received from nuclear operations at the Hanford Site since 1944. To identify groups that may have received doses, population estimates containing age, race, and sex detail for ten counties in Washington and Oregon for the years 1940 to 1980 were prepared by the Demographics Laboratory under a subcontract with the Pacific Northwest Laboratory (PNL). A data base of population information was developed from census reports and published and unpublished collections from the Washington State Office of Financial Management and Center for Population Research. Three estimation methods were then explored: the cohort-component model, cohort interpolation, and age-group interpolation. The estimates generated through cohort and age-group interpolation are considered adequate for initial use in the HEDR Project. Results are presented in two forms: (1) county populations by sex and single year of age and (2) county populations by sex and race for age groupings. These results are made available to the HEDR Project for further refinement into population estimates by county census divisions.

  7. Forensic dental age estimation by measuring root dentin translucency area using a new digital technique.

    PubMed

    Acharya, Ashith B

    2014-05-01

    Dentin translucency measurement is an easy yet relatively accurate approach to postmortem age estimation. Translucency area represents a two-dimensional change and may reflect age variations better than length. Manually measuring area is challenging and this paper proposes a new digital method using commercially available computer hardware and software. Area and length were measured on 100 tooth sections (age range, 19-82 years) of 250 μm thickness. Regression analysis revealed lower standard error of estimate and higher correlation with age for length than for area (R = 0.62 vs. 0.60). However, test of regression formulae on a control sample (n = 33, 21-85 years) showed smaller mean absolute difference (8.3 vs. 8.8 years) and greater frequency of smaller errors (73% vs. 67% age estimates ≤ ± 10 years) for area than for length. These suggest that digital area measurements of root translucency may be used as an alternative to length in forensic age estimation.

  8. Preliminary age, growth and maturity estimates of spotted ratfish (Hydrolagus colliei) in British Columbia

    NASA Astrophysics Data System (ADS)

    King, J. R.; McPhie, R. P.

    2015-05-01

    The spotted ratfish (Hydrolagus colliei) is a chimaeroid ranging from southeast Alaska to Baja California and found at depths of up to 1029 m. Despite being widespread and ubiquitous, few biological parameter estimates exist for spotted ratfish due to a lack of suitable ageing structures to estimate age and growth. We present preliminary results of age, growth and maturity estimates based on a new method in which tritor ridges are counted on the vomerine tooth plate. We also provide a method for estimating the number of worn tritor ridges based on tooth plate diameter measurements for the spotted ratfish. The tritor ridges are distinct bumps that are easy to identify and precision estimates between readers suggests that this method is transferable. Tritor ridges are a potential structure for estimating age in H. colliei and we provide recommendations for future research to improve the method. We sampled 269 spotted ratfish captured in trawl surveys off the coast British Columbia ranging in size from 74 to 495 mm in precaudal length (PCL). The estimated ages ranged from 2 to 16 years for males and from 2 to 21 years for females. The von Bertalanffy, von Bertalanffy with known size at birth, Gompertz and logistic growth models were fitted to the data. Based on Akaike information criterion corrected for sample size and number of parameters estimated, the logistic growth curve was selected as most suitable. The logistic growth model yielded the following parameter estimates: Linf=407.22 mm (PCL), k=0.23 year-1, t0=-7.06 years for males; L∞=494.52 mm (PCL), k=0.26 year-1, t0=-8.35 years for females. Estimated ages at 50% maturity were 12 and 14 years for males and females, respectively. Correspondingly, the size at 50% maturity estimates was smaller for males (302 mm, PCL) than females (393 mm, PCL). Both estimates are larger than those made for spotted ratfish off of California indicating regional differences in life history traits for this species. Our preliminary

  9. Implications of age and conditional survival estimates for patients with melanoma.

    PubMed

    Banerjee, Mousumi; Lao, Christopher D; Wancata, Lauren M; Muenz, Daniel G; Haymart, Megan R; Wong, Sandra L

    2016-02-01

    Overall cancer incidence is decreasing, whereas melanoma cases are increasing. Conditional survival estimates offer a more accurate prognosis for patients the farther they are from time of diagnosis. The effect of age and stage on a melanoma patient's conditional survival estimate is unknown. Surveillance, Epidemiology, and End Results data were utilized to identify newly diagnosed cutaneous melanoma patients (N=95 041), from 1998 to 2005, with up to 12 years of follow-up. Estimates of disease-specific survival by stage and age were determined by Cox regression analysis and transformed to estimated conditional 5-year survival. Localized melanoma patients have an excellent 5-year survival at diagnosis and over subsequent years. For patients with localized and regional disease, an age effect is present for disease-specific mortality when comparing older patients (70-79 years) with younger patients (<30 years): hazard ratio (HR) for mortality 3.79 [95% confidence interval (CI) 3.01-4.84] and HR 2.36 (95% CI 1.93-2.91), respectively. No age effect difference is observed in disease-specific survival for advanced disease: HR 1.14 (95% CI 0.87-1.53). Over time, conditional survival estimates improve for older patients with localized and regional disease. This improvement is not seen in distant disease, neither is the age gradient. Disease-specific mortality and conditional survival for patients with localized and regional melanomas are initially impacted by older age, with effects dissipating over time. Age does not affect survival in patients with advanced disease. Understanding the conditional 5-year disease-specific survival of melanoma based on age and stage can help patients and physicians, informing decision-making about treatment and surveillance. PMID:26479218

  10. Implications of age and conditional survival estimates for patients with melanoma

    PubMed Central

    Banerjee, Mousumi; Lao, Christopher D.; Wancata, Lauren M.; Muenz, Daniel G.; Haymart, Megan R.; Wong, Sandra L.

    2016-01-01

    Objective Overall cancer incidence is decreasing while melanoma cases increase. Conditional survival estimates offer a more accurate prognosis for patients as they survive past diagnosis. It is unknown the effect age and stage has on a melanoma patient’s conditional survival estimate. Methods Surveillance, Epidemiology, End Results (SEER) data was utilized, identifying new diagnosis cutaneous melanoma patients (N=95,041), from 1998–2005, with up to 12 year follow up. Estimates of disease-specific survival by stage and age were determined by Cox regression and transformed to estimate conditional five-year survival. Results Localized melanoma patients have an excellent five-year survival at diagnosis and subsequent years. For patients with localized and regional disease, an age effect is present for disease-specific mortality when comparing older patients (70–79 years) to younger patients (<30 years): hazard ratio (HR) for mortality 3.79 (95% confidence interval (CI) 3.01–4.84) and HR 2.36 (95% CI 1.93–2.91), respectively. No age effect difference is observed in disease-specific survival for advanced disease: HR 1.14 (95% CI 0.87–1.53). Over time conditional survival estimates improve for older patients with localized and regional disease. This improvement is not seen in distant disease nor is the age gradient. Conclusions Disease-specific mortality and conditional survival for patients with localized and regional melanoma is initially impacted by older age with effects dissipating over time. Age does not affect survival in patients with advanced disease. Understanding the conditional five-year disease-specific survival of melanoma based on age and stage can help patients and physicians, informing decision making about treatment and surveillance. PMID:26479218

  11. Age estimation using carpals: study of a Slovenian sample to test Cameriere's method.

    PubMed

    Cameriere, Roberto; Ferrante, Luigi; Ermenc, Branko; Mirtella, Dora; Strus, Katja

    2008-01-30

    Carpals are often used as age indicators. In a recent study, Cameriere et al. studied the use of the ratio between the total area of carpal bones and epiphyses of the ulna and radius (Bo) and carpals (Ca) as age indicators. The present study, of a sample of 158 Slovenian children and adolescents aged between 6 and 16 years, focused on analysing the best regression for age estimation. The regression model yielded the following equation: age=-3.411+0.942 g+20.927(Bo/Ca), and explained 91.6% of total variance (R(2)=0.916). The median of the absolute values of residuals (observed age minus predicted age) was 0.09 years, with a quartile deviation of 0.786 years, and a standard error of estimate of 0.658 years. Comparisons between the previous equation referring to Slovenian children and the equivalent linear equation proposed by Cameriere et al. did not reveal any significant differences between the intercepts and slopes of the two linear models. These results suggested a common regression model for both Italian and Slovenian samples. The common regression model, describing age as a linear function of gender and Bo/Ca ratio, yielded the following linear regression formula: age=-2.907+0.408 g+20.757(Bo/Ca). This model explained 86% of total variance (R(2)=0.86). The median of the absolute values of residuals (observed age minus predicted age) was 0.02 years, with a quartile deviation of 1.02 years and a standard error of estimate of 0.96 years.

  12. Computed tomography evaluation of the iliac crest apophysis: age estimation in living individuals.

    PubMed

    Ekizoglu, Oguzhan; Inci, Ercan; Erdil, Irem; Hocaoglu, Elif; Bilgili, Mustafa Gokhan; Kazimoglu, Cemal; Reisoglu, Ali; Can, Ismail Ozgur

    2016-07-01

    Determination of the ossification properties of the iliac apophysis is important not only in the clinical evaluation of patients undergoing orthopedic surgery but also in age estimation studies for forensic purposes. The literature includes both anthropological and radiological (conventional radiography, ultrasonography, and magnetic resonance imaging modalities) investigations of the different staging systems used for these purposes. In this study, we assessed the utility of computed tomography (CT) of the iliac crest apophysis in estimating forensic age. CT scans of the iliac crest apophysis of 380 patients (187 females, 193 males, and 10-29 years of age) were evaluated according to the four-stage system. Further subclassification did not give data properly due to the reference length measurement of the iliac wing with CT. Thus, in our series, stage 2 was first seen in 12 years of age and stage 3 in those 14 years of age in both sexes and on both sides of the pelvis. Stage 4 was first seen in 17 years of both sexes but only on the right side; on the left side, it appeared in females 18 years of age and in males 17 years of age. Present data was found consistent with previous pelvic radiographic findings. First seen ages for stage 2 and 3 are 12 and 14 years respectively which presented valuable information for legally important age thresholds. However, disadvantages of CT, including high-dose radiation exposure to gonads, the difficulty of evaluating the iliac crest, and the age boundary of 17 years, could make this method infeasible, as compared with hand wrist and pelvic radiographic methods. CT of the iliac crest has probably a greater utility where preexisting CT scans of the pelvic region are available, and it may be considered as a supportive method for age-estimation purposes. PMID:26914804

  13. A new approach to constrain basal helium flux into aquifers for better estimation of groundwater ages by Helium 4

    NASA Astrophysics Data System (ADS)

    Matsumoto, Takuya; Sturchio, Neil C.; Chang, Hung K.; Gastmans, Didier; Araguas-Araguas, Luis J.; Jiang, Wei; Lu, Zheng-Tian; Mueller, Peter; Yokochi, Reika; Purtschert, Roland; Zongyu, Chen; Shuiming, Hu; Aggarwal, Pradeep K.

    2016-04-01

    Estimation of groundwater age through the combined use of isotope methods and groundwater flow modelling is the common approach used for developing the required level of knowledge in the case of groundwater pumped from deep aquifers. For more than 50 years radiocarbon and tritium have been the common tools used in isotope hydrology studies to provide first estimates of groundwater age and dynamics. The half-life of carbon-14 (5730 years) and the complex geochemistry of carbon species in most environments have limited the proper characterization of groundwater flow patterns in large sedimentary basins and deep aquifers to ages more recent than about 40 000 years. Over the last years, a number of long-live radionuclides and other isotopes have been tested as more reliable age indicators by specialised laboratories. Among these methods, chlorine-36 (half-life of 300 000 yr) has been used with mixed results, mainly due to problems derived from in-situ production of this radionuclide. Uranium isotopes have also been used in a few instances, but never became a routine tool. Accumulation of helium-4 in deep groundwaters has also been proposed and used in a few instance, but one major obstacle in the 4He dating method is a difficulty in assessing a rate constant of 4He input into aquifers (namely, the entering basal 4He flux). In this context, recent breakthrough developments in analytical methods allow the precise determination of dissolved noble gases in groundwater as well as trace-level noble gas radionuclides present in very old groundwaters. Atom trap trace analysis, or ATTA, has dramatically improved over the last years the processing of very small amount of noble gases, providing now real possibilities for routine measurements of extremely low concentration of exotic radionuclides dissolved in groundwater, such as krypton-81 (half-life 229 000 years). Atom trap trace analysis involves the selective capture of individual atoms of a given isotope using six laser

  14. Estimation of Heterogeneity in Diagnostic Parameters of Age-related Diseases.

    PubMed

    Blokh, David; Stambler, Ilia

    2014-08-01

    The heterogeneity of parameters is a ubiquitous biological phenomenon, with critical implications for biological systems functioning in normal and diseased states. We developed a method to estimate the level of objects set heterogeneity with reference to particular parameters and applied it to type II diabetes and heart disease, as examples of age-related systemic dysfunctions. The Friedman test was used to establish the existence of heterogeneity. The Newman-Keuls multiple comparison method was used to determine clusters. The normalized Shannon entropy was used to provide the quantitative evaluation of heterogeneity. There was obtained an estimate for the heterogeneity of the diagnostic parameters in healthy subjects, as well as in heart disease and type II diabetes patients, which was strongly related to their age. With aging, as with the diseases, the level of heterogeneity (entropy) was reduced, indicating a formal analogy between these phenomena. The similarity of the patterns in aging and disease suggested a kind of "early aging" of the diseased subjects, or alternatively a "disease-like" aging process, with reference to these particular parameters. The proposed method and its validation on the chronic age-related disease samples may support a way toward a formal mathematical relation between aging and chronic diseases and a formal definition of aging and disease, as determined by particular heterogeneity (entropy) changes. PMID:25110613

  15. Improvements to photometry. Part 1: Better estimation of derivatives in extinction and transformation equations

    NASA Technical Reports Server (NTRS)

    Young, Andrew T.

    1988-01-01

    Atmospheric extinction in wideband photometry is examined both analytically and through numerical simulations. If the derivatives that appear in the Stromgren-King theory are estimated carefully, it appears that wideband measurements can be transformed to outside the atmosphere with errors no greater than a millimagnitude. A numerical analysis approach is used to estimate derivatives of both the stellar and atmospheric extinction spectra, avoiding previous assumptions that the extinction follows a power law. However, it is essential to satify the requirements of the sampling theorem to keep aliasing errors small. Typically, this means that band separations cannot exceed half of the full width at half-peak response. Further work is needed to examine higher order effects, which may well be significant.

  16. Algorithmically-derived variables and their use in toxicity estimation: A review

    SciTech Connect

    Niemi, G.; Basak, S.

    1994-12-31

    The use of algorithmically-derived variables are those calculated directly and precisely from mathematical representations of a chemical such as those based on graph-theory. Many studies have shown a high correspondence between these variables and physicochemical measurements of a diverse set of compounds. Moreover, these variables have proven highly useful in the estimation of many parameters related with toxicity including n-octanol water partition coefficient, toxicity bioconcentration factors, and mode of toxic action. This paper is a review of how these variables have been used for the estimation of these properties. It will also describe the important role that algorithmically-derived variables may play in the future of aquatic toxicology and the development of quantitative structure-activity relationships (QSAR`s).

  17. Single Pass LiDAR-derived Estimate of Site Productivity in Western Oregon

    NASA Astrophysics Data System (ADS)

    McAdam, E.; Hilker, T.; Waring, R. H.; Sousa, C. H. R. D.; Moura, Y. M.

    2014-12-01

    Accurate estimates of forest growth at different ages are essential to evaluate the effect of a changing climate and to adjust management practices accordingly. Most current approaches are spatially discrete and therefore unable to predict forest growth accurately across landscapes. While airborne LiDAR has been widely used in forestry, it can only estimate growth rates with repeated passes. In contrast, Landsat imagery records disturbances (at 30 m resolution) but is unable to measure changes in growth rates. Historical archives of Landsat imagery provided us a way of knowing when and where even-aged stands of Pseudotsuga menziesii (Douglas-fir) were cut and replanted. Since early growth rates are nearly linear with age, the height of dominant trees recorded in one pass by LiDAR yields a direct measure of growth and likely changes as stands age under recent climatic conditions. Process-based growth models are available to assess possible shifts in the growth rates of stands under a changing climate; the accuracy of such model predictions can be evaluated with additional LiDAR coverage. In this study we use the Physiological Principles Predicting Growth Model (3-PG) to estimate site index at the landscape level to predict site productivity based on the year of stand establishment obtained from Landsat, and one-pass airborne LiDAR measurement of forest height. We are monitoring forest plantations of known ages and with data on their current age we will calculate site index for 60 separate sites across western Oregon. The results of this study will allow us to create updated site index maps for the state of Oregon under varying climate scenarios.

  18. Use of MODIS-Derived Fire Radiative Energy to Estimate Smoke Aerosol Emissions over Different Ecosystems

    NASA Technical Reports Server (NTRS)

    Ichoku, Charles; Kaufman, Yoram J.

    2003-01-01

    Biomass burning is the main source of smoke aerosols and certain trace gases in the atmosphere. However, estimates of the rates of biomass consumption and emission of aerosols and trace gases from fires have not attained adequate reliability thus far. Traditional methods for deriving emission rates employ the use of emission factors e(sub x), (in g of species x per kg of biomass burned), which are difficult to measure from satellites. In this era of environmental monitoring from space, fire characterization was not a major consideration in the design of the early satellite-borne remote sensing instruments, such as AVHRR. Therefore, although they are able to provide fire location information, they were not adequately sensitive to variations in fire strength or size, because their thermal bands used for fire detection saturated at the lower end of fire radiative temperature range. As such, hitherto, satellite-based emission estimates employ proxy techniques using satellite derived fire pixel counts (which do not express the fire strength or rate of biomass consumption) or burned areas (which can only be obtained after the fire is over). The MODIS sensor, recently launched into orbit aboard EOS Terra (1999) and Aqua (2002) satellites, have a much higher saturation level and can, not only detect the fire locations 4 times daily, but also measures the at-satellite fire radiative energy (which is a measure of the fire strength) based on its 4 micron channel temperature. Also, MODIS measures the optical thickness of smoke and other aerosols. Preliminary analysis shows appreciable correlation between the MODIS-derived rates of emission of fire radiative energy and smoke over different regions across the globe. These relationships hold great promise for deriving emission coefficients, which can be used for estimating smoke aerosol emissions from MODIS active fire products. This procedure has the potential to provide more accurate emission estimates in near real

  19. Effects of brain-derived neurotrophic factor on dopaminergic function and motor behavior during aging.

    PubMed

    Boger, H A; Mannangatti, P; Samuvel, D J; Saylor, A J; Bender, T S; McGinty, J F; Fortress, A M; Zaman, V; Huang, P; Middaugh, L D; Randall, P K; Jayanthi, L D; Rohrer, B; Helke, K L; Granholm, A-C; Ramamoorthy, S

    2011-03-01

    Brain-derived neurotrophic factor (BDNF) is critical in synaptic plasticity and in the survival and function of midbrain dopamine neurons. In this study, we assessed the effects of a partial genetic deletion of BDNF on motor function and dopamine (DA) neurotransmitter measures by comparing Bdnf(+/-) with wildtype mice (WT) at different ages. Bdnf(+/-) and WT mice had similar body weights until 12 months of age; however, at 21 months, Bdnf(+/-) mice were significantly heavier than WT mice. Horizontal and vertical motor activity was reduced for Bdnf(+/-) compared to WT mice, but was not influenced by age. Performance on an accelerating rotarod declined with age for both genotypes and was exacerbated for Bdnf(+/-) mice. Body weight did not correlate with any of the three behavioral measures studied. Dopamine neurotransmitter markers indicated no genotypic difference in striatal tyrosine hydroxylase, DA transporter (DAT) or vesicular monoamine transporter 2 (VMAT2) immunoreactivity at any age. However, DA transport via DAT (starting at 12 months) and VMAT2 (starting at 3 months) as well as KCl-stimulated DA release were reduced in Bdnf(+/-) mice and declined with age suggesting an increasingly important role for BDNF in the release and uptake of DA with the aging process. These findings suggest that a BDNF expression deficit becomes more critical to dopaminergic dynamics and related behavioral activities with increasing age.

  20. Age-Infusion Approach to Derive Injury Risk Curves for Dummies from Human Cadaver Tests

    PubMed Central

    Yoganandan, Narayan; Banerjee, Anjishnu; Pintar, Frank A.

    2015-01-01

    Injury criteria and risk curves are needed for anthropomorphic test devices (dummies) to assess injuries for improving human safety. The present state of knowledge is based on using injury outcomes and biomechanical metrics from post-mortem human subject (PMHS) and mechanical records from dummy tests. Data from these models are combined to develop dummy injury assessment risk curves (IARCs)/dummy injury assessment risk values (IARVs). This simple substitution approach involves duplicating dummy metrics for PMHS tested under similar conditions and pairing with PMHS injury outcomes. It does not directly account for the age of each specimen tested in the PMHS group. Current substitution methods for injury risk assessments use age as a covariate and dummy metrics (e.g., accelerations) are not modified so that age can be directly included in the model. The age-infusion methodology presented in this perspective article accommodates for an annual rate factor that modifies the dummy injury risk assessment responses to account for the age of the PMHS that the injury data were based on. The annual rate factor is determined using human injury risk curves. The dummy metrics are modulated based on individual PMHS age and rate factor, thus “infusing” age into the dummy data. Using PMHS injuries and accelerations from side-impact experiments, matched-pair dummy tests, and logistic regression techniques, the methodology demonstrates the process of age-infusion to derive the IARCs and IARVs. PMID:26697422

  1. Estimating Derived Response Levels at the Savannah River Site for Use with Emergency Response Models

    SciTech Connect

    Simpkins, A.A.

    2002-12-06

    Emergency response computer models at the Savannah River Site (SRS) are coupled with real-time meteorological data to estimate dose to individuals downwind of accidental radioactive releases. Currently, these models estimate doses for inhalation and shine pathways, but do not consider dose due to ingestion of contaminated food products. The Food and Drug Administration (FDA) has developed derived intervention levels (DIL) which refer to the radionuclide-specific concentration in food present throughout the relevant period of time, with no intervention, that could lead to an individual receiving a radiation dose equal to the protective action guide. In the event of an emergency, concentrations in various food types are compared with these levels to make interdictions decisions. Prior to monitoring results being available, concentrations in the environmental media (i.e. soil), called derived response levels (DRLs), can be estimated from the DILs and directly compared with computer output to provide preliminary guidance as to whether intervention is necessary. Site-specific derived response levels (DRLs) are developed for ingestion pathways pertinent to SRS: milk, meat, fish, grain, produce, and beverage. This provides decision-makers with an additional tool for use immediately following an accident prior to the acquisition of food monitoring data.

  2. Estimation of longitudinal stability and control derivatives for an icing research aircraft from flight data

    NASA Technical Reports Server (NTRS)

    Batterson, James G.; Omara, Thomas M.

    1989-01-01

    The results of applying a modified stepwise regression algorithm and a maximum likelihood algorithm to flight data from a twin-engine commuter-class icing research aircraft are presented. The results are in the form of body-axis stability and control derivatives related to the short-period, longitudinal motion of the aircraft. Data were analyzed for the baseline (uniced) and for the airplane with an artificial glaze ice shape attached to the leading edge of the horizontal tail. The results are discussed as to the accuracy of the derivative estimates and the difference between the derivative values found for the baseline and the iced airplane. Additional comparisons were made between the maximum likelihood results and the modified stepwise regression results with causes for any discrepancies postulated.

  3. [Age estimation based on sternal rib ends changes in Bosnian male population].

    PubMed

    Sarajlić, Nermin

    2006-01-01

    One of the methods used for age estimation of exhumed remains of the missing persons from the recent war in Bosnia and Herzegovina is Iscan et al. rib phase analysis method, developed o n American population. Several researches have tested this method on other populations and proposed modifications for age estimation in a certain population. The purpose of this study is to test the applicability of the mentioned method for age assessment on Bosnian male population. The sample consistS of ribs from 410 identified deceased persons, from the recent war in Bosnia and Herzegovina. Whenever possible, the 4th rib has been used. In other cases 3rd, 5th or 6th rib has been used. Adjusted age ranges for each phase were developed specifically for the Bosnian male population. Up to the phase 7 Bosnians reach and finish each phase a little later t han Americans. However phases 7 and 8 were achieved andended earlier in Bosnian population.

  4. Radiological pitfalls of age estimation in adopted children: a case report.

    PubMed

    Gibelli, D; De Angelis, D; Cattaneo, C

    2015-04-01

    Age estimation has a relevant importance in assessing adopted children, also in cases where the age of the minor seems unquestioned, since pathological conditions may radically alter bodily growth. This may lead to an incorrect age evaluation, with consequent social and psychological problems linked to an inadequate collocation in public school. This study aims at exposing a case report concerning age estimation for a newly adopted child from Cambodia; previous clinical documentation reported information suggesting possible malnutrition, which was verified by the observation of a general disalignment of bone and dental structures. This example shows the importance of a thorough forensic evaluation of adopted children from other countries in order to verify the possible environmental modification of physiological growth even where it seems not to be needed, and represents a caveat for clinical and social personnel dealing with adoption procedures.

  5. Some aspects of cool main sequence star ages derived from stellar rotation (gyrochronology)

    NASA Astrophysics Data System (ADS)

    Barnes, S. A.; Spada, F.; Weingrill, J.

    2016-09-01

    Rotation periods for cool stars can be measured with good precision by monitoring starspot light modulation. Observations have shown that the rotation periods of dwarf stars of roughly solar metallicity have such systematic dependencies on stellar age and mass that they can be used to derive reliable ages, a procedure called gyrochronology. We review the method and show illustrative cases, including recent ground- and space-based data. The age uncertainties approach 10 % in the best cases, making them a valuable complement to, and constraint on, asteroseismic or other ages. Edited, updated, and refereed version of a presentation at the WE-Heraeus-Seminar in Bad Honnef, Germany: Reconstructing the Milky Way's History: Spectroscopic Surveys, Asteroseismology and Chemodynamical Models

  6. Diphenylamine and derivatives as predictors of gunpowder age by means of HPLC and statistical models.

    PubMed

    López-López, María; Bravo, J Carlos; García-Ruiz, Carmen; Torre, Mercedes

    2013-01-15

    The gunpowder age is information of great importance that could help to establish safety regulations related to the propellants use and manipulation. In this work, a forced aging treatment (65°C for 120 days) was applied to four gunpowders stabilized with diphenylamine (DPA). The evolution of DPA and derivatives (N-nitroso-DPA, 2-nitro-DPA, 4-nitro-DPA, and 4-4'-dinitro-DPA) concentration during the days was leaded by High Performance Liquid Chromatography (HPLC). The variation with time of the peak areas of these compounds was used to construct different statistical models that could predict the gunpowders age. These models were validated using nitrocellulose-based gunpowders of known manufacture date. Models that best predicted the gunpowder age provided prediction errors lower than 6, 4, and 2 years for single-base gunpowders with dinitrotoluene (≥ 10%(m/m)), single-base gunpowders and double-base gunpowders, respectively.

  7. Estimating cropland NPP using national crop inventory and MODIS derived crop specific parameters

    NASA Astrophysics Data System (ADS)

    Bandaru, V.; West, T. O.; Ricciuto, D. M.

    2011-12-01

    Estimates of cropland net primary production (NPP) are needed as input for estimates of carbon flux and carbon stock changes. Cropland NPP is currently estimated using terrestrial ecosystem models, satellite remote sensing, or inventory data. All three of these methods have benefits and problems. Terrestrial ecosystem models are often better suited for prognostic estimates rather than diagnostic estimates. Satellite-based NPP estimates often underestimate productivity on intensely managed croplands and are also limited to a few broad crop categories. Inventory-based estimates are consistent with nationally collected data on crop yields, but they lack sub-county spatial resolution. Integrating these methods will allow for spatial resolution consistent with current land cover and land use, while also maintaining total biomass quantities recorded in national inventory data. The main objective of this study was to improve cropland NPP estimates by using a modification of the CASA NPP model with individual crop biophysical parameters partly derived from inventory data and MODIS 8day 250m EVI product. The study was conducted for corn and soybean crops in Iowa and Illinois for years 2006 and 2007. We used EVI as a linear function for fPAR, and used crop land cover data (56m spatial resolution) to extract individual crop EVI pixels. First, we separated mixed pixels of both corn and soybean that occur when MODIS 250m pixel contains more than one crop. Second, we substituted mixed EVI pixels with nearest pure pixel values of the same crop within 1km radius. To get more accurate photosynthetic active radiation (PAR), we applied the Mountain Climate Simulator (MTCLIM) algorithm with the use of temperature and precipitation data from the North American Land Data Assimilation System (NLDAS-2) to generate shortwave radiation data. Finally, county specific light use efficiency (LUE) values of each crop for years 2006 to 2007 were determined by application of mean county inventory

  8. Using a Near-Infrared Spectrometer to Estimate the Age of Anopheles Mosquitoes Exposed to Pyrethroids

    PubMed Central

    Sikulu, Maggy T.; Majambere, Silas; Khatib, Bakar O.; Ali, Abdullah S.; Hugo, Leon E.; Dowell, Floyd E.

    2014-01-01

    We report on the accuracy of using near-infrared spectroscopy (NIRS) to predict the age of Anopheles mosquitoes reared from wild larvae and a mixed age-wild adult population collected from pit traps after exposure to pyrethroids. The mosquitoes reared from wild larvae were estimated as <7 or ≥7 d old with an overall accuracy of 79%. The age categories of Anopheles mosquitoes that were not exposed to the insecticide papers were predicted with 78% accuracy whereas the age categories of resistant, susceptible and mosquitoes exposed to control papers were predicted with 82%, 78% and 79% accuracy, respectively. The ages of 85% of the wild-collected mixed-age Anopheles were predicted by NIRS as ≤8 d for both susceptible and resistant groups. The age structure of wild-collected mosquitoes was not significantly different for the pyrethroid-susceptible and pyrethroid-resistant mosquitoes (P = 0.210). Based on these findings, NIRS chronological age estimation technique for Anopheles mosquitoes may be independent of insecticide exposure and the environmental conditions to which the mosquitoes are exposed. PMID:24594705

  9. Reddening and age of six poorly studied star clusters of the Large Magellanic Cloud derived from integrated spectra

    NASA Astrophysics Data System (ADS)

    Minniti, J. H.; Ahumada, A. V.; Clariá, J. J.; Benítez-Llambay, A.

    2014-05-01

    Aims: To increase the number of studied star clusters (SCs) of the Large Magellanic Cloud (LMC), we present flux-calibrated integrated spectra in the optical range (λ = 3700-6800 Å) for six poorly studied LMC SCs of IVA type. This type corresponds to the age range between 200 and 400 Myr. We also aim at creating a new template spectrum representative of this age range at the metallicity level of the LMC. Methods: Foreground reddening E(B - V) values and ages are derived by applying the template matching method that consists of comparing the line strengths and continuum distribution of the cluster spectra with those of template cluster spectra with known properties. The equivalent width (EW) of the Balmer lines and the diagnostic diagrams involving the sum of EWs of selected spectral lines were also employed as age indicators. Results: For the first time, we provide estimates of the clusters' reddenings and ages. As expected, all the clusters appear to be of nearly the same age, their mean value being (400 ± 100) Myr, while the resulting mean E(B - V) values range between 0.00 and 0.10 mag. Conclusions: The present cluster sample complements previous ones in an effort to gather a spectral library with several clusters per age bin. By averaging the reddening-corrected integrated spectra, weighted by their signal-to-noise ratios (S/N), a new high S/N template spectrum of 400 Myr has been created. Integrated spectra for each star cluster are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/565/A49

  10. Dental age estimation from the developmental stage of the third molars in Iranian population.

    PubMed

    Rai, Balwant; Kaur, Jasdeep; Jafarzadeh, Hamid

    2010-08-01

    A sharp increase in forensic age estimation of living persons has been observed in recent years. However, ethnic populations residing in different countries have been insufficiently analyzed. The aim of this study was to achieve a referral database and regression equations for dental age estimation of unaccompanied minors of Iran nationality. A total of 1200 orthopantomograms were collected from original Iran and equally divided in age categories between 10 and 27 years. On the radiographs, the developmental stage of the third molars was scored applying a Demirjian et al. scoring technique. Inter- and intra-observer reliabilities were tested using kappa statistics. Correlation between the scores of all four wisdom maxillary and mandibular third molars teeth and left/right symmetry were evaluated with spearman correlation coefficient. Student's t-test on asymmetry was performed and regression formulas were calculated. The present database was the first to assemble third molar developmental scores on radiographs of Iran individuals and provided more appropriate dental age estimation of unaccompanied Iran minors. To enhance the accuracy of forensic age estimates based on third molars mineralization, the use of population-specific standards is recommended.

  11. Age estimation of the Deccan Traps from the North American apparent polar wander path

    NASA Technical Reports Server (NTRS)

    Stoddard, Paul R.; Jurdy, Donna M.

    1988-01-01

    It has recently been proposed that flood basalt events, such as the eruption of the Deccan Traps, have been responsible for mass extinctions. To test this hypothesis, accurate estimations of the ages and duration of these events are needed. In the case of the Deccan Traps, however, neither age nor duration of emplacement is well constrianed; measured ages range from 40 to more than 80 Myr, and estimates of duration range from less than 1 to 67 Myr. To make an independent age determination, paleomagnetic and sea-floor-spreading data are used, and the associated errors are estimated. The Deccan paleomagnetic pole is compared with the reference apparent polar wander path of North America by rotating the positions of the paleomagnetic pole for the Deccan Traps to the reference path for a range of assumed ages. Uncertainties in the apparent polar wander path, Deccan paleopole position, and errors resulting from the plate reconstruction are estimated. It is suggested that 83-70 Myr is the most likely time of extrusion of these volcanic rocks.

  12. Age estimation based on pelvic ossification using regression models from conventional radiography.

    PubMed

    Zhang, Kui; Dong, Xiao-Ai; Fan, Fei; Deng, Zhen-Hua

    2016-07-01

    To establish regression models for age estimation from the combination of the ossification of iliac crest and ischial tuberosity. One thousand three hundred and seventy-nine conventional pelvic radiographs at the West China Hospital of Sichuan University between January 2010 and June 2012 were evaluated retrospectively. The receiver operating characteristic analysis was performed to measure the value of estimation of 18 years of age with the classification scheme for the iliac crest and ischial tuberosity. Regression analysis was performed, and formulas for calculating approximate chronological age according to the combination developmental status of the ossification for the iliac crest and ischial tuberosity were developed. The areas under the receiver operating characteristic (ROC) curves were above 0.9 (p < 0.001), indicating a good prediction of the grading systems, and the cubic regression model was found to have the highest R-square value (R (2) = 0.744 for female and R (2) = 0.753 for male). The present classification scheme for apophyseal iliac crest ossification and the ischial tuberosity may be used for age estimation. And the present established cubic regression model according to the combination developmental status of the ossification for the iliac crest and ischial tuberosity can be used for age estimation. PMID:27169673

  13. Enhancing radar estimates of precipitation over complex terrain using information derived from an orographic precipitation model

    NASA Astrophysics Data System (ADS)

    Crochet, Philippe

    2009-10-01

    SummaryThe objective of this paper is to present a radar-based quantitative precipitation estimation algorithm and assess its quality over the complex terrain of western Iceland. The proposed scheme deals with the treatment of beam blockage, anomalous propagation, vertical profile of reflectivity and includes a radar adjustment technique compensating for range, orographic effects and variations in the Z-R relationship. The quality of the estimated precipitation is remarkably enhanced after post-processing and in reasonably good agreement with what is known about the spatial distribution of precipitation in the studied area from both rain gauge observations and a gridded dataset derived from an orographic precipitation model. The results suggest that this methodology offers a credible solution to obtain an estimate of the distribution of precipitation in mountainous terrain and appears to be of practical value to meteorologists and hydrologists.

  14. Lidar-derived estimate and uncertainty of carbon sink in successional phases of woody encroachment

    USGS Publications Warehouse

    Sankey, Temuulen; Shrestha, Rupesh; Sankey, Joel B.; Hardgree, Stuart; Strand, Eva

    2013-01-01

    Woody encroachment is a globally occurring phenomenon that contributes to the global carbon sink. The magnitude of this contribution needs to be estimated at regional and local scales to address uncertainties present in the global- and continental-scale estimates, and guide regional policy and management in balancing restoration activities, including removal of woody plants, with greenhouse gas mitigation goals. The objective of this study was to estimate carbon stored in various successional phases of woody encroachment. Using lidar measurements of individual trees, we present high-resolution estimates of aboveground carbon storage in juniper woodlands. Segmentation analysis of lidar point cloud data identified a total of 60,628 juniper tree crowns across four watersheds. Tree heights, canopy cover, and density derived from lidar were strongly correlated with field measurements of 2613 juniper stems measured in 85 plots (30 × 30 m). Aboveground total biomass of individual trees was estimated using a regression model with lidar-derived height and crown area as predictors (Adj. R2 = 0.76, p 2. Uncertainty in carbon storage estimates was examined with a Monte Carlo approach that addressed major error sources. Ranges predicted with uncertainty analysis in the mean, individual tree, aboveground woody C, and associated standard deviation were 0.35 – 143.6 kg and 0.5 – 1.25 kg, respectively. Later successional phases of woody encroachment had, on average, twice the aboveground carbon relative to earlier phases. Woody encroachment might be more successfully managed and balanced with carbon storage goals by identifying priority areas in earlier phases of encroachment where intensive treatments are most effective.

  15. A TECHNIQUE FOR ASSESSING THE ACCURACY OF SUB-PIXEL IMPERVIOUS SURFACE ESTIMATES DERIVED FROM LANDSAT TM IMAGERY

    EPA Science Inventory

    We developed a technique for assessing the accuracy of sub-pixel derived estimates of impervious surface extracted from LANDSAT TM imagery. We utilized spatially coincident
    sub-pixel derived impervious surface estimates, high-resolution planimetric GIS data, vector--to-
    r...

  16. A method for estimating gestational age of fetal remains based on long bone lengths.

    PubMed

    Carneiro, Cristiana; Curate, Francisco; Cunha, Eugénia

    2016-09-01

    The estimation of gestational age (GA) in fetal human remains is important in forensic settings, particularly to assess fetal viability, in addition to often being the only biological profile parameter that can be assessed with some accuracy for non-adults. The length of long bone diaphysis is one of the most frequently used methods for fetal age estimation. The main objective of this study was to present a simple and objective method for estimating GA based on the measurements of the diaphysis of the femur, tibia, fibula, humerus, ulna, and radius. Conventional least squares regression equations (classical and inverse calibration approaches) and quick reference tables were generated. A supplementary objective was to compare the performance of the new formulae against previously published models. The sample comprised 257 fetuses (136 females and 121 males) with known GA (between 12 and 40 weeks) and was selected based on clinical and pathological information. All measurements were performed on radiographic images acquired in anonymous clinical autopsy records from spontaneous and therapeutic abortions in two Portuguese hospitals. The proposed technique is straightforward and reproducible. The models for the GA estimation are exceedingly accurate and unbiased. Comparisons between inverse and classical calibration show that both perform exceptionally well, with high accuracy and low bias. Also, the newly developed equations generally outperform earlier methods of GA estimation in forensic contexts. Quick reference tables for each long bone are now available. The obtained models for the estimation of gestational age are of great applicability in forensic contexts. PMID:27251047

  17. Cost-Sensitive Local Binary Feature Learning for Facial Age Estimation.

    PubMed

    Lu, Jiwen; Liong, Venice Erin; Zhou, Jie

    2015-12-01

    In this paper, we propose a cost-sensitive local binary feature learning (CS-LBFL) method for facial age estimation. Unlike the conventional facial age estimation methods that employ hand-crafted descriptors or holistically learned descriptors for feature representation, our CS-LBFL method learns discriminative local features directly from raw pixels for face representation. Motivated by the fact that facial age estimation is a cost-sensitive computer vision problem and local binary features are more robust to illumination and expression variations than holistic features, we learn a series of hashing functions to project raw pixel values extracted from face patches into low-dimensional binary codes, where binary codes with similar chronological ages are projected as close as possible, and those with dissimilar chronological ages are projected as far as possible. Then, we pool and encode these local binary codes within each face image as a real-valued histogram feature for face representation. Moreover, we propose a cost-sensitive local binary multi-feature learning method to jointly learn multiple sets of hashing functions using face patches extracted from different scales to exploit complementary information. Our methods achieve competitive performance on four widely used face aging data sets. PMID:26415174

  18. Age-at-maturity estimates for Atlantic coast female striped bass

    USGS Publications Warehouse

    Berlinsky, David L.; Fabrizio, Mary C.; O'Brien, John F.; Specker, Jennifer L.

    1995-01-01

    This study was undertaken to estimate the percentage of mature female striped bass Morone saxatilis present in each age-class during annual coastal feeding migration. Migratory striped bass (N = 302) were sampled in coastal Rhode Island waters during spring (May-June) and fall (September-November) from 1985 to 1987. Stocks were identified by analysis of morphometric characters and isoelectric focusing of eye-lens proteins. Histological sections of ovarian tissue were used to categorize maturity state. Fish were considered mature if a class of oocytes measuring at least 150 μm and containing cytoplasmic inclusions was found in the ovarian sections. All females whose age at next potential spawning was 7 and older were mature. Our empirical observations indicated that 12% of fish in age-class 4, 34% of fish in age-class 5, and 77% of fish in age-class 6 were mature. The estimate of the proportion of mature fish in age-class 5 differs significantly from that of Merriman (1941), who also examined coastal migrants. No significant differences were found in maturity estimates of fish from stocks of different origin.

  19. Problems in estimating age-specific survival rates from recovery data of birds ringed as young

    USGS Publications Warehouse

    Anderson, D.R.; Burnham, Kenneth P.; White, Gary C.

    1985-01-01

    (1) The life table model is frequently employed in the analysis of ringer samples of young in bird populations. The basic model is biologically unrealistic and of little use in making inferences concerning age-specific survival probabilities. (2) This model rests on a number of restrictive assumptions, the failure of which causes serious biases. Several important assumptions are not met with real data and the estimators of age-specific survival are not robust enough to these failures. (3) Five major problems in the use of the life table method are reviewed. Examples are provided to illustrate several of the problems involved in using this method in making inferences about survival rates and its age-specific nature. (4) We conclude that this is an invalid procedure and it should not be used. Furthermore, ringing studies involving only young birds are pointless as regards survival estimation because no valid method exists for estimating age-specific or time-specific survival rates from such data. (5) In our view, inferences about age-specific survival rates are possible only if both young and adult (or young, subadult and adult) age classes are ringed each year for k years (k ≥ 2).

  20. Estimating ages of white-tailed deer: Age and sex patterns of error using tooth wear-and-replacement and consistency of cementum annuli

    USGS Publications Warehouse

    Samuel, Michael D.; Storm, Daniel J.; Rolley, Robert E.; Beissel, Thomas; Richards, Bryan J.; Van Deelen, Timothy R.

    2014-01-01

    The age structure of harvested animals provides the basis for many demographic analyses. Ages of harvested white-tailed deer (Odocoileus virginianus) and other ungulates often are estimated by evaluating replacement and wear patterns of teeth, which is subjective and error-prone. Few previous studies however, examined age- and sex-specific error rates. Counting cementum annuli of incisors is an alternative, more accurate method of estimating age, but factors that influence consistency of cementum annuli counts are poorly known. We estimated age of 1,261 adult (≥1.5 yr old) white-tailed deer harvested in Wisconsin and Illinois (USA; 2005–2008) using both wear-and-replacement and cementum annuli. We compared cementum annuli with wear-and-replacement estimates to assess misclassification rates by sex and age. Wear-and-replacement for estimating ages of white-tailed deer resulted in substantial misclassification compared with cementum annuli. Age classes of females were consistently underestimated, while those of males were underestimated for younger age classes but overestimated for older age classes. Misclassification resulted in an impression of a younger age-structure than actually was the case. Additionally, we obtained paired age-estimates from cementum annuli for 295 deer. Consistency of paired cementum annuli age-estimates decreased with age, was lower in females than males, and decreased as age estimates became less certain. Our results indicated that errors in the wear-and-replacement techniques are substantial and could impact demographic analyses that use age-structure information. 

  1. Improving estimates of surface water radiocarbon reservoir ages in the northeastern Atlantic Ocean.

    NASA Astrophysics Data System (ADS)

    Greenop, Rosanna; Burke, Andrea; Rae, James; Austin, William; Reimer, Paula; Blaauw, Maarten; Crocker, Anya; Chalk, Thomas; Barker, Stephen; Knutz, Paul; Hall, Ian

    2016-04-01

    Radiocarbon measurements from foraminifera in marine sediment cores are widely used to constrain age models and the timing of paleoceanographic events, as well as past changes in ocean circulation and carbon cycling. However, the use of radiocarbon for both dating and palaeoceanographic applications is limited in sediment cores by a lack of knowledge about the surface ocean radiocarbon reservoir age and how it varies in both space and time. Typically, to convert a planktic radiocarbon age into a calendar age, an assumed constant reservoir age is applied. However, there is mounting evidence to suggest that this assumption of constant reservoir age through time is an oversimplification, particularly for the high latitude oceans during the cold climates of the last glacial and deglacial periods. Here we present new high-resolution radiocarbon records together with tephra tie points and 230-thorium (230Th) constrained sedimentation rates to improve estimates of radiocarbon reservoir age in the Northeast Atlantic Ocean. In addition we will explore the impact of the new reservoir ages for both the age models of the cores studied, as well as the palaeoceanographic implications of these reservoir age changes during intervals of rapid climate change over the past 40,000 years.

  2. The Influence of Aging on the Regenerative Potential of Human Adipose Derived Mesenchymal Stem Cells

    PubMed Central

    Marycz, Krzysztof; Henry, Brandon Michael

    2016-01-01

    Tissue regeneration using human adipose derived mesenchymal stem cells (hASCs) has significant potential as a novel treatment for many degenerative bone and joint diseases. Previous studies have established that age negatively affects the proliferation status and the osteogenic and chondrogenic differentiation potential of mesenchymal stem cells. The aim of this study was to assess the age-related maintenance of physiological function and differentiation potential of hASCs in vitro. hASCs were isolated from patients of four different age groups: (1) >20 years (n = 7), (2) >50 years (n = 7), (3) >60 years (n = 7), and (4) >70 years (n = 7). The hASCs were characterized according to the number of fibroblasts colony forming unit (CFU-F), proliferation rate, population doubling time (PDT), and quantified parameters of adipogenic, chondrogenic, and osteogenic differentiation. Compared to younger cells, aged hASCs had decreased proliferation rates, decreased chondrogenic and osteogenic potential, and increased senescent features. A shift in favor of adipogenic differentiation with increased age was also observed. As many bone and joint diseases increase in prevalence with age, it is important to consider the negative influence of age on hASCs viability, proliferation status, and multilineage differentiation potential when considering the potential therapeutic applications of hASCs. PMID:26941800

  3. Personalizing Age of Cancer Screening Cessation Based on Comorbidity: Model estimates of harms and benefits

    PubMed Central

    Lansdorp-Vogelaar, Iris; Gulati, Roman; Mariotto, Angela B; Schechter, Clyde B; de Carvalho, Tiago M; Knudsen, Amy B; van Ravesteyn, Nicolien T; Heijnsdijk, Eveline AM; Pabiniak, Chester; van Ballegooijen, Marjolein; Rutter, Carolyn M; Kuntz, Karen M; Feuer, Eric J; Etzioni, Ruth; de Koning, Harry J; Zauber, Ann G; Mandelblatt, Jeanne S

    2014-01-01

    Background Harms and benefits of cancer screening depend on age and comorbidity, yet reliable estimates are lacking. Objective To estimate the harms and benefits of cancer screening by age and comorbidity to inform decisions about screening cessation. Design Collaborative modeling with seven well-established cancer simulation models and common data on average and comorbidity level-specific life expectancy from SEER-Medicare. Setting US population. Patients US cohorts aged 66–90 years in 2010 with average health or one of four comorbidity levels (linked to specific conditions): none, mild, moderate, or severe. Intervention Mammography, prostate-specific antigen testing, or fecal immunochemical testing. Measurements Lifetime cancer deaths prevented and life-years gained (benefits); false-positive tests and overdiagnosed cancers (harms). For each comorbidity level: the age at which harms and benefits of screening were similar to that for individuals with average health undergoing screening at age 74. Results Screening 1000 women with average life expectancy at age 74 for breast cancer resulted in 79–96 (range across models) false-positives, 0.5–0.8 overdiagnosed cancers, and 0.7–0.9 breast cancer deaths prevented. While absolute numbers of harms and benefits differed across cancer sites, the ages at which to cease screening were highly consistent across models and cancer sites when based on harm-benefit ratios comparable to screening average-health individuals at age 74. For individuals with no, mild, moderate, and severe comorbidities, screening until ages of 76, 74, 72, and 66, respectively, resulted in similar harms and benefits as for average-health individuals. Limitations Comorbidity only influenced life expectancy. Conclusion Comorbidity is an important determinant of harms and benefits of screening. Estimates of screening benefits and harms by comorbidity can inform discussions between providers and their older patients about personalizing decisions

  4. Estimating crop net primary production using inventory data and MODIS-derived parameters

    SciTech Connect

    Bandaru, Varaprasad; West, Tristram O.; Ricciuto, Daniel M.; Izaurralde, Roberto C.

    2013-06-03

    National estimates of spatially-resolved cropland net primary production (NPP) are needed for diagnostic and prognostic modeling of carbon sources, sinks, and net carbon flux. Cropland NPP estimates that correspond with existing cropland cover maps are needed to drive biogeochemical models at the local scale and over national and continental extents. Existing satellite-based NPP products tend to underestimate NPP on croplands. A new Agricultural Inventory-based Light Use Efficiency (AgI-LUE) framework was developed to estimate individual crop biophysical parameters for use in estimating crop-specific NPP. The method is documented here and evaluated for corn and soybean crops in Iowa and Illinois in years 2006 and 2007. The method includes a crop-specific enhanced vegetation index (EVI) from the Moderate Resolution Imaging Spectroradiometer (MODIS), shortwave radiation data estimated using Mountain Climate Simulator (MTCLIM) algorithm and crop-specific LUE per county. The combined aforementioned variables were used to generate spatially-resolved, crop-specific NPP that correspond to the Cropland Data Layer (CDL) land cover product. The modeling framework represented well the gradient of NPP across Iowa and Illinois, and also well represented the difference in NPP between years 2006 and 2007. Average corn and soybean NPP from AgI-LUE was 980 g C m-2 yr-1 and 420 g C m-2 yr-1, respectively. This was 2.4 and 1.1 times higher, respectively, for corn and soybean compared to the MOD17A3 NPP product. Estimated gross primary productivity (GPP) derived from AgI-LUE were in close agreement with eddy flux tower estimates. The combination of new inputs and improved datasets enabled the development of spatially explicit and reliable NPP estimates for individual crops over large regional extents.

  5. Smoke aerosol properties and ageing effects for Northern temperate and boreal regions derived from AERONET source and age attribution

    NASA Astrophysics Data System (ADS)

    Nikonovas, T.; North, P. R. J.; Doerr, S. H.

    2015-03-01

    Particulate emissions from wildfires impact human health and have a large but uncertain effect on climate. Modelling schemes depend on information about emission factors, emitted particle microphysical and optical properties and ageing effects, while satellite retrieval algorithms make use of characteristic aerosol models to improve retrieval. Ground based remote sensing provides detailed aerosol characterisation, but does not contain information on source. Here, a method is presented to estimate plume origin land cover type and age for AERONET aerosol observations, employing trajectory modelling using the HYSPLIT model, and satellite active fire and aerosol optical thickness (AOT) observations from MODIS and AATSR. It is applied to AERONET stations located in or near Northern temperate and boreal forests, for the period 2002-2013. The results from 629 fire attributions indicate significant differences in size distributions and particle optical properties between different land cover types. Smallest fine mode median radius are attributed to plumes from cropland - natural vegetation mosaic (0.143 μm) and grasslands (0.147 μm) fires. Evergreen needleleaf forest emissions show a significantly smaller fine mode median radius (0.164 μm) than plumes from woody savannas (0.184 μm) and mixed forest (0.193 μm) fires. Smoke plumes are predominantly scattering for all of the classes with median single scattering albedo at 440 nm (SSA(440)) values close to 0.95 except the cropland emissions which have a SSA(440) value of 0.9. Overall fine mode volume median radius increase rate is 0.0095 μm per day for the first 4 days of ageing and 0.0084 μm per day for seven days of ageing. Changes in size were consistent with a decrease in Angstrom Exponent and increase in Asymmetry parameter. No significant changes in SSA(λ) with ageing were found. These estimates have implications for

  6. Age estimation in children by measurement of open apices in teeth with Bayesian calibration approach.

    PubMed

    Cameriere, R; Pacifici, A; Pacifici, L; Polimeni, A; Federici, F; Cingolani, M; Ferrante, L

    2016-01-01

    Age estimation from teeth by radiological analysis, in both children and adolescents, has wide applications in several scientific and forensic fields. In 2006, Cameriere et al. proposed a regression method to estimate chronological age in children, according to measurements of open apices of permanent teeth. Although several regression models are used to analyze the relationship between age and dental development, one serious limitation is the unavoidable bias in age estimation when regression models are used. The aim of this paper is to develop a full Bayesian calibration method for age estimation in children according to the sum of open apices, S, of the seven left permanent mandibular teeth. This cross-sectional study included 2630 orthopantomographs (OPGs) from healthy living Italian subjects, aged between 4 and 17 years and with no obvious developmental abnormalities. All radiographs were in digital format and were processed by the ImageJ computer-aided drawing program. The distance between the inner side of the open apex was measured for each tooth. Dental maturity was then evaluated according to the sum of normalized open apices (S). Intra- and inter-observer agreement was satisfactory, according to an intra-class correlation coefficient of S on 50 randomly selected OPGs. Mean absolute errors were 0.72 years (standard deviation 0.60) and 0.73 years (standard deviation 0.61) in boys and girls, respectively. The mean interquartile range (MIQR) of the calibrating distribution was 1.37 years (standard deviation 0.46) and 1.51 years (standard deviation 0.52) in boys and girls, respectively. Estimate bias was βERR=-0.005 and 0.003 for boys and girls, corresponding to a bias of a few days for all individuals in the sample. Neither of the βERR values was significantly different from 0 (p>0.682). In conclusion, the Bayesian calibration method overcomes problems of bias in age estimation when regression models are used, and appears to be suitable for assessing both

  7. Estimating Black Carbon Aging Time-Scales with a Particle-Resolved Aerosol Model

    SciTech Connect

    Riemer, Nicole; West, Matt; Zaveri, Rahul A.; Easter, Richard C.

    2010-01-13

    Understanding the aging process of aerosol particles is important for assessing their chemical reactivity, cloud condensation nuclei activity, radiative properties and health impacts. In this study we investigate the aging of black carbon containing particles in an idealized urban plume using a new approach, the particleresolved aerosol model PartMC-MOSAIC. We present a method to estimate aging time-scales using an aging criterion based on cloud condensation nuclei activation. The results show a separation into a daytime regime where condensation dominates and a nighttime regime where coagulation dominates. For the chosen urban plume scenario, depending on the supersaturation threshold, the values for the aging timescales vary between 0.06 hours and 10 hours during the day, and between 6 hours and 20 hours during the night.

  8. Body composition and body hydration in old age estimated by means of skinfold thickness and deuterium dilution.

    PubMed

    Virgili, F; D'Amicis, A; Ferro-Luzzi, A

    1992-01-01

    In this study a group of 30 women and 30 men aged 60-90 years was examined. Body density was predicted from the sum of four skinfold thickness (SFT) as described by Durnin and Womersley (1974). Body composition, expressed as a percentage of total body weight as fat mass (FM) and fat free mass (FFM) was calculated by means of Siri's formula (Siri 1961). Total body water (TBW) was measured from the dilution of an oral deuterium dose and FFM calculated assuming a hydration of 73.2%. The FM% predicted from SFT showed a slight but not significant decreasing age trend from 28.3% to 25.4% in men, and from 40.3% to 37.8% in women. Body hydration (about 50% of body weight in men and 44% in women) remained constant throughout the age range. FFM obtained from TBW assuming a constant hydration of FFM, was found to be unchanged with age. FM% predicted from SFT was correlated with values obtained from TBW on an individual basis (R2 = 0.38; p less than 0.0001 in men and R2 = 0.31; p less than 0.002 in women), but the scatter was large. The Bland and Altman statistical analysis (Bland and Altman 1986) suggests that the discrepancy between the two estimates tends to be significantly more positive with increasing fatness of the subject. The assumption of a constant hydration of FFM between individuals and with advancing age was tested. The hydration of FFM was calculated as the ratio between TBW (from deuterium dilution) and FFM (estimated from SFT). The wide range of values (50% to 90%) suggests large inter-individual differences. The mean values were lower than commonly reported, and differed with age and sex. In men, FFM hydration steadily decreases with age from the 7th decade (70.2 +/- 7.7%) to the 10th decade (65.9 +/- 8.2%). Women showed higher average figures than those of men and a lower age-associated decline (72.5% and 68.5% respectively). Our results suggest that FFM hydration decreases with age, and this indicates the need to develop age-related correction factors in

  9. Assessing Forest NPP: BIOME-BGC Predictions versus BEF Derived Estimates

    NASA Astrophysics Data System (ADS)

    Hasenauer, H.; Pietsch, S. A.; Petritsch, R.

    2007-05-01

    Forest productivity has always been a major issue within sustainable forest management. While in the past terrestrial forest inventory data have been the major source for assessing forest productivity, recent developments in ecosystem modeling offer an alternative approach using ecosystem models such as Biome-BGC to estimate Net Primary Production (NPP). In this study we compare two terrestrial driven approaches for assessing NPP: (i) estimates from a species specific adaptation of the biogeochemical ecosystem model BIOME-BGC calibrated for Alpine conditions; and (ii) NPP estimates derived from inventory data using biomass expansion factors (BEF). The forest inventory data come from 624 sample plots across Austria and consist of repeated individual tree observations and include growth as well as soil and humus information. These locations are covered with spruce, beech, oak, pine and larch stands, thus addressing the main Austrian forest types. 144 locations were previously used in a validating effort to produce species-specific parameter estimates of the ecosystem model. The remaining 480 sites are from the Austrian National Forest Soil Survey carried out at the Federal Research and Training Centre for Forests, Natural Hazards and Landscape (BFW). By using diameter at breast height (dbh) and height (h) volume and subsequently biomass of individual trees were calculated, aggregated for the whole forest stand and compared with the model output. Regression analyses were performed for both volume and biomass estimates.

  10. Biometric and Eddy-Covariance Based Estimates of Ecosystem Carbon Exchange in an Age-Sequence of Temperate Pine Forests

    NASA Astrophysics Data System (ADS)

    Peichl, M.; Arain, M. A.; Brodeur, J. J.; Khomik, M.

    2009-05-01

    We determined and compared annual carbon (C) exchanges from biometric and eddy-covariance (EC) measurements in an age-sequence (6-, 19-, 34-, 69-years old) of managed pine (Pinus strobus L.) forests in southern Ontario from 2005-2007. The biometric approach determined annual above- and belowground tree biomass production from site-specific allometric biomass equations depending on either tree diameter at breast height (DBH) only (method B1) or on DBH with tree height as additional variable (method B2). In addition, detritus production and heterotrophic soil respiration were determined. Data from continuous closed- path measurements at the oldest site and from a roving open-path system among the three younger sites provided EC-based estimates of C exchanges (method EC). The contribution of individual net primary productivity (NPP) components varied considerably with stand age, suggesting different dominant fluxes and uncertainty levels occurring at various forest development stages. All methods produced similar patterns for inter-annual variations with highest (lowest) C fluxes in 2006 (2005). While on an annual basis, differences between methods ranged from ± 4-67% for estimates of annual net ecosystem productivity (NEP), the differences were within ± 15% when averaged over three years, except for the 34-year old stand. Mean annual NEP was estimated by the biometric method B1 (B2) as 1 (N.A.), 394 (634), 134 (265), and 124 (272) g C m-2 y-1 compared to 47, 724, 408, and 119 g C m-2 y-1 by the EC method for the 6-, 19-, 34-, 69-years old stands, respectively. The biometric method B1 agreed best with the EC estimates in the youngest and the oldest stand, but estimated considerably lower productivity rates than the EC method in the two middle-age stands in which method B2 showed a better agreement with method EC by accounting for the vigorous height growth in these stands. Thus, our comparison study shows that the use of inadequate allometric equations may

  11. Wild-derived mouse stocks: an underappreciated tool for aging research

    PubMed Central

    2008-01-01

    Virtually all biomedical research makes use of a relatively small pool of laboratory-adapted, inbred, isogenic stocks of mice. Although the advantages of these models are many, there are a number of disadvantages as well. When studying a multifaceted process such as aging, the problems associated with using laboratory stocks are greatly inflated. On the other hand, wild-derived mouse stocks, loosely defined here as either wild-caught individuals or the recent progeny of wild-caught individuals, have much to offer to biogerontology research. Hence, the aims of this review are threefold: (1) to (re)acquaint readers with the pros and cons of using a typical inbred laboratory mouse model for aging research; (2) to reintroduce the notion of using wild-derived mouse stocks in aging research as championed by Austad, Miller and others for more than a decade, and (3) to provide an overview of recent advances in biogerontology using wild-derived mouse stocks. PMID:19424863

  12. Derivation of Forest Inventory Parameters for Carbon Estimation Using Terrestrial LIDAR

    NASA Astrophysics Data System (ADS)

    Prasad Kalwar, Om Prakash; Hussin, Yousif A.; Weir, Michael J. C.; Karna, Yogendra K.

    2016-06-01

    This research was conducted to derive forest sample plot inventory parameters from terrestrial LiDAR (T-LiDAR) for estimating above ground biomass (AGB)/carbon stocks in primary tropical rain forest. Inventory parameters of all sampled trees within circular plots of 500 m2 were collected from field observations while T-LiDAR data were acquired through multiple scanning using Reigl VZ-400 scanner. Pre-processing and registration of multiple scans were done in RSCAN PRO software. Point cloud constructing individual sampled tree was extracted and tree inventory parameters (diameter at breast height-DBH and tree height) were measured manually. AGB/carbon stocks were estimated using Chave et al., (2005) allometric equation. An average 80 % of sampled trees were detected from point cloud of the plots. The average of plots values of R2 and RMSE for manually measured DBHs were 0.95, 2.7 cm respectively. Similarly, the average of plots values of R2 and RMSE for manually measured trees heights were 0.77, 2.96 m respectively. The average value of AGB/carbon stocks estimated from field measurements and T-LiDAR manually derived DBHs and trees heights were 286 Mg ha-1 and 134 Mg ha-1; and 278 M ha-1 and 130 Mg ha-1 respectively. The R2 values for the estimated AGB and AGC were both 0.93 and corresponding RMSE values were 42.4 Mg ha-1 and 19.9 Mg ha-1 respectively. AGB and AGC were estimated with 14.8 % accuracy.

  13. Optical coherence tomography: age estimation of Calliphora vicina pupae in vivo?

    PubMed

    Brown, Katherine; Harvey, Michelle

    2014-09-01

    Necrophagous blowfly pupae are valuable contributors to the estimation of post-mortem interval, should an accurate age estimate be obtained. At present, this is reliant on a combination of rearing and destructive methods conducted on preserved samples, including morphological observation and gene expression analyses. This study demonstrates the use of optical coherence tomography (OCT) as a tool for in vivo morphological observation and pupal age estimation. Using a Michelson OCT microscope, alive and preserved four and ten-day old Calliphora vicina pupae were scanned in different orientations. Two and three-dimensional images were created. Morphological characteristics such as the brain, mouthparts and legs were identifiable in both living and preserved samples, with distinct differences noted between the two ages. Absorption of light by the puparium results in a vertical resolution of 1-2 mm, preventing observation of deeper tissues. The use of contrast agents or a longer wavelength laser would improve the images obtainable. At present, the data suggests OCT provides a primary view of external and internal morphology, which can be used to distinguish younger and older pupae for further analysis of age and PMI estimation.

  14. Age-Related Changes in Children's Executive Functions and Strategy Selection: A Study in Computational Estimation

    ERIC Educational Resources Information Center

    Lemaire, Patrick; Lecacheur, Mireille

    2011-01-01

    Third, fifth, and seventh graders selected the best strategy (rounding up or rounding down) for estimating answers to two-digit addition problems. Executive function measures were collected for each individual. Data showed that (a) children's skill at both strategy selection and execution improved with age and (b) increased efficiency in executive…

  15. Age estimation by pulp/tooth ratio in lower premolars by orthopantomography.

    PubMed

    Cameriere, Roberto; De Luca, Stefano; Alemán, Inmaculada; Ferrante, Luigi; Cingolani, Mariano

    2012-01-10

    Accurate age estimation has always been a problem for forensic scientists, and apposition of secondary dentine is often used as an indicator of age. Since 2004, in order to examine patterns of secondary dentine apposition, Cameriere et al. have been extensively studying the pulp/tooth area ratio of the canines by panoramic and peri-apical X-ray images. The main aim of this paper is to examine the relationship between age and age-related changes in the pulp/tooth area ratio in monoradicular teeth, with the exception of canines, by orthopantomography. A total of 606 orthopantomograms of Spanish white Caucasian patients (289 women and 317 men), aged between 18 and 75 years and coming from Bilbao and Granada (Spain), was analysed. Regression analysis of age of monoradicular teeth indicated that the lower premolars were the most closely correlated with age. An ANCOVA did not show significant differences between men and women. Multiple regression analysis, with age as dependent variable and pulp/tooth area ratio as predictor, yielded several formulae. R(2) ranged from 0.69 to 0.75 for a single lower premolar tooth and from 0.79 to 0.86 for multiple lower premolar teeth. Depending on the available number of premolar teeth, the mean of the absolute values of residual standard error, at 95% confidence interval, ranged between 4.34 and 6.02 years, showing that the pulp/tooth area ratio is a useful variable for assessing age with reasonable accuracy.

  16. Human dental age estimation using third molar developmental stages: Accuracy of age predictions not using country specific information.

    PubMed

    Thevissen, P W; Alqerban, A; Asaumi, J; Kahveci, F; Kaur, J; Kim, Y K; Pittayapat, P; Van Vlierberghe, M; Zhang, Y; Fieuws, S; Willems, G

    2010-09-10

    Unquestionable forensic age investigations are based on statistical models constructed on a sample containing subjects of identical origin as the examined individual. In cases where corresponding models are unavailable, the established report has to describe the possible effects of this unrelated information on the predicted age outcome. The aim of this study is to collect country specific databases of third molar development and to verify how the related dental age estimations are influenced if we were to use dental developmental information only from Belgium or from all collected countries together. Data containing third molar developmental stages scored following Gleiser and Hunt (modified by Köhler) were collected from 9 country specific populations (Belgium, China, Japan, Korea, Poland, Thailand, Turkey, Saudi-Arabia and South-India). Age predictions were obtained from a training dataset and validated on a test dataset. Bayes rule using the repeated third molar scores is applied to get age predictions and prediction intervals. Three age predictions were compared for males and females separately. For the first prediction, the training dataset contains only Belgian subjects. For the second prediction, the training dataset for each country consists only of subjects of the country itself. For the final prediction, subjects from all countries are pooled into one common training dataset. Besides the (absolute) difference between the chronological age and the predicted age, specific interest lies in the juvenile-adult distinction. In the age range from 16 to 22 years 6982 subjects (3189 male and 3793 female) were analyzed. Using information on third molar development from Belgium compared to information from the country specific databases hardly increased the mean absolute differences (MAD) and mean squared errors (MSE): the MAD and MSE increased on average with 0.5 and 2.5 months with maximal increases of, respectively 1.6 and 7.3 months. Using information from all

  17. Human dental age estimation using third molar developmental stages: Accuracy of age predictions not using country specific information.

    PubMed

    Thevissen, P W; Alqerban, A; Asaumi, J; Kahveci, F; Kaur, J; Kim, Y K; Pittayapat, P; Van Vlierberghe, M; Zhang, Y; Fieuws, S; Willems, G

    2010-09-10

    Unquestionable forensic age investigations are based on statistical models constructed on a sample containing subjects of identical origin as the examined individual. In cases where corresponding models are unavailable, the established report has to describe the possible effects of this unrelated information on the predicted age outcome. The aim of this study is to collect country specific databases of third molar development and to verify how the related dental age estimations are influenced if we were to use dental developmental information only from Belgium or from all collected countries together. Data containing third molar developmental stages scored following Gleiser and Hunt (modified by Köhler) were collected from 9 country specific populations (Belgium, China, Japan, Korea, Poland, Thailand, Turkey, Saudi-Arabia and South-India). Age predictions were obtained from a training dataset and validated on a test dataset. Bayes rule using the repeated third molar scores is applied to get age predictions and prediction intervals. Three age predictions were compared for males and females separately. For the first prediction, the training dataset contains only Belgian subjects. For the second prediction, the training dataset for each country consists only of subjects of the country itself. For the final prediction, subjects from all countries are pooled into one common training dataset. Besides the (absolute) difference between the chronological age and the predicted age, specific interest lies in the juvenile-adult distinction. In the age range from 16 to 22 years 6982 subjects (3189 male and 3793 female) were analyzed. Using information on third molar development from Belgium compared to information from the country specific databases hardly increased the mean absolute differences (MAD) and mean squared errors (MSE): the MAD and MSE increased on average with 0.5 and 2.5 months with maximal increases of, respectively 1.6 and 7.3 months. Using information from all

  18. Adipose-Derived Mesenchymal Stem Cells Restore Impaired Mucosal Immune Responses in Aged Mice.

    PubMed

    Aso, Kazuyoshi; Tsuruhara, Akitoshi; Takagaki, Kentaro; Oki, Katsuyuki; Ota, Megumi; Nose, Yasuhiro; Tanemura, Hideki; Urushihata, Naoki; Sasanuma, Jinichi; Sano, Masayuki; Hirano, Atsuyuki; Aso, Rio; McGhee, Jerry R; Fujihashi, Kohtaro

    2016-01-01

    It has been shown that adipose-derived mesenchymal stem cells (AMSCs) can differentiate into adipocytes, chondrocytes and osteoblasts. Several clinical trials have shown the ability of AMSCs to regenerate these differentiated cell types. Age-associated dysregulation of the gastrointestinal (GI) immune system has been well documented. Our previous studies showed that impaired mucosal immunity in the GI tract occurs earlier during agingthan is seen in the systemic compartment. In this study, we examined the potential of AMSCs to restore the GI mucosal immune system in aged mice. Aged (>18 mo old) mice were adoptively transferred with AMSCs. Two weeks later, mice were orally immunized with ovalbumin (OVA) plus cholera toxin (CT) three times at weekly intervals. Seven days after the final immunization, when fecal extract samples and plasma were subjected to OVA- and CT-B-specific ELISA, elevated levels of mucosal secretory IgA (SIgA) and plasma IgG antibody (Ab) responses were noted in aged mouse recipients. Similar results were also seen aged mice which received AMSCs at one year of age. When cytokine production was examined, OVA-stimulated Peyer's patch CD4+ T cells produced increased levels of IL-4. Further, CD4+ T cells from the lamina propria revealed elevated levels of IL-4 and IFN-γ production. In contrast, aged mice without AMSC transfer showed essentially no OVA- or CT-B-specific mucosal SIgA or plasma IgG Ab or cytokine responses. Of importance, fecal extracts from AMSC transferred aged mice showed neutralization activity to CT intoxication. These results suggest that AMSCs can restore impaired mucosal immunity in the GI tract of aged mice. PMID:26840058

  19. Adipose-Derived Mesenchymal Stem Cells Restore Impaired Mucosal Immune Responses in Aged Mice

    PubMed Central

    Aso, Kazuyoshi; Tsuruhara, Akitoshi; Takagaki, Kentaro; Oki, Katsuyuki; Ota, Megumi; Nose, Yasuhiro; Tanemura, Hideki; Urushihata, Naoki; Sasanuma, Jinichi; Sano, Masayuki; Hirano, Atsuyuki; Aso, Rio; McGhee, Jerry R.; Fujihashi, Kohtaro

    2016-01-01

    It has been shown that adipose-derived mesenchymal stem cells (AMSCs) can differentiate into adipocytes, chondrocytes and osteoblasts. Several clinical trials have shown the ability of AMSCs to regenerate these differentiated cell types. Age-associated dysregulation of the gastrointestinal (GI) immune system has been well documented. Our previous studies showed that impaired mucosal immunity in the GI tract occurs earlier during agingthan is seen in the systemic compartment. In this study, we examined the potential of AMSCs to restore the GI mucosal immune system in aged mice. Aged (>18 mo old) mice were adoptively transferred with AMSCs. Two weeks later, mice were orally immunized with ovalbumin (OVA) plus cholera toxin (CT) three times at weekly intervals. Seven days after the final immunization, when fecal extract samples and plasma were subjected to OVA- and CT-B-specific ELISA, elevated levels of mucosal secretory IgA (SIgA) and plasma IgG antibody (Ab) responses were noted in aged mouse recipients. Similar results were also seen aged mice which received AMSCs at one year of age. When cytokine production was examined, OVA-stimulated Peyer’s patch CD4+ T cells produced increased levels of IL-4. Further, CD4+ T cells from the lamina propria revealed elevated levels of IL-4 and IFN-γ production. In contrast, aged mice without AMSC transfer showed essentially no OVA- or CT-B-specific mucosal SIgA or plasma IgG Ab or cytokine responses. Of importance, fecal extracts from AMSC transferred aged mice showed neutralization activity to CT intoxication. These results suggest that AMSCs can restore impaired mucosal immunity in the GI tract of aged mice. PMID:26840058

  20. An Empirically Derived Method for Remotely-Sensed Estimation of River Depth

    NASA Astrophysics Data System (ADS)

    Mersel, M. K.; Smith, L. C.; Durand, M. T.; Andreadis, K.

    2011-12-01

    Satellite remote sensing has created exciting new opportunities for the study of fluvial systems, providing a global-scale perspective that can only be achieved from space. The NASA Surface Water and Ocean Topography (SWOT) satellite mission, planned for launch in 2019, has the potential to greatly enhance our understanding of the spatial and temporal dynamics of rivers worldwide. Through repeat-pass measurements of water-surface elevation and width, SWOT will directly observe changes in river discharge for many of the world's rivers (those greater than ~100 meters wide). However, because SWOT will only measure channel bathymetry down to the lowest water level encountered over the mission lifetime, true discharge will not be directly measured and must thus be estimated. Perhaps the greatest limiting factor to accurate estimates of river discharge using SWOT measurements is the estimation of channel depth. Here we explore the potential for empirically derived channel depth estimates using synthetic SWOT retrievals. The one-dimensional hydraulic modeling program, HEC-RAS, is used to model water-surface elevation and width at over 800 surveyed cross-sections along reaches of the Rio Grande, Upper Mississippi, Illinois, and Jamuna-Meghna rivers. Maximum channel depth and average channel depth are then estimated along each reach at cross-section locations that meet quantitative criteria related to changes in water-surface elevation and width. Results suggest that there are optimal locations for estimating river depth along a given river reach selected on the basis of geomorphic characteristics, that can be detected from space. The relative simplicity of such an approach provides promising potential for the retrieval of river depth from SWOT-type measurements directly, and thus for improved global estimation of river discharge from space.

  1. Estimated maximal and current brain volume predict cognitive ability in old age.

    PubMed

    Royle, Natalie A; Booth, Tom; Valdés Hernández, Maria C; Penke, Lars; Murray, Catherine; Gow, Alan J; Maniega, Susana Muñoz; Starr, John; Bastin, Mark E; Deary, Ian J; Wardlaw, Joanna M

    2013-12-01

    Brain tissue deterioration is a significant contributor to lower cognitive ability in later life; however, few studies have appropriate data to establish how much influence prior brain volume and prior cognitive performance have on this association. We investigated the associations between structural brain imaging biomarkers, including an estimate of maximal brain volume, and detailed measures of cognitive ability at age 73 years in a large (N = 620), generally healthy, community-dwelling population. Cognitive ability data were available from age 11 years. We found positive associations (r) between general cognitive ability and estimated brain volume in youth (male, 0.28; females, 0.12), and in measured brain volume in later life (males, 0.27; females, 0.26). Our findings show that cognitive ability in youth is a strong predictor of estimated prior and measured current brain volume in old age but that these effects were the same for both white and gray matter. As 1 of the largest studies of associations between brain volume and cognitive ability with normal aging, this work contributes to the wider understanding of how some early-life factors influence cognitive aging.

  2. The utility of ancient human DNA for improving allele age estimates, with implications for demographic models and tests of natural selection

    PubMed Central

    Sams, Aaron J.; Hawks, John; Keinan, Alon

    2015-01-01

    The age of polymorphic alleles in humans is often estimated from population genetic patterns in extant human populations, such as allele frequencies, linkage disequilibrium, and rate of mutations. Ancient DNA can improve the accuracy of such estimates, as well as facilitate testing the validity of demographic models underlying many population genetic methods. Specifically, the presence of an allele in a genome derived from an ancient sample testifies that the allele is at least as old as that sample. In this study, we consider a common method for estimating allele age based on allele frequency as applied to variants from the US National Institutes of Health (NIH) Heart, Lung, and Blood Institute (NHLBI) Exome Sequencing Project. We view these estimates in the context of the presence or absence of each allele in the genomes of the 5300 year old Tyrolean Iceman, Ötzi, and of the 50,000 year old Altai Neandertal. Our results illuminate the accuracy of these estimates and their sensitivity to demographic events that were not included in the model underlying age estimation. Specifically, allele presence in the Iceman genome provides a good fit of allele age estimates to the expectation based on the age of that specimen. The equivalent based on the Neandertal genome leads to a poorer fit. This is likely due in part to the older age of the Neandertal and the older time of the split between modern humans and Neandertals, but also due to gene flow from Neandertals to modern humans not being considered in the underlying demographic model. Thus, the incorporation of ancient DNA can improve allele age estimation, demographic modeling, and tests of natural selection. Our results also point to the importance of considering a more diverse set of ancient samples for understanding the geographic and temporal range of individual alleles. PMID:25467111

  3. The utility of ancient human DNA for improving allele age estimates, with implications for demographic models and tests of natural selection.

    PubMed

    Sams, Aaron J; Hawks, John; Keinan, Alon

    2015-02-01

    The age of polymorphic alleles in humans is often estimated from population genetic patterns in extant human populations, such as allele frequencies, linkage disequilibrium, and rate of mutations. Ancient DNA can improve the accuracy of such estimates, as well as facilitate testing the validity of demographic models underlying many population genetic methods. Specifically, the presence of an allele in a genome derived from an ancient sample testifies that the allele is at least as old as that sample. In this study, we consider a common method for estimating allele age based on allele frequency as applied to variants from the US National Institutes of Health (NIH) Heart, Lung, and Blood Institute (NHLBI) Exome Sequencing Project. We view these estimates in the context of the presence or absence of each allele in the genomes of the 5300 year old Tyrolean Iceman, Ötzi, and of the 50,000 year old Altai Neandertal. Our results illuminate the accuracy of these estimates and their sensitivity to demographic events that were not included in the model underlying age estimation. Specifically, allele presence in the Iceman genome provides a good fit of allele age estimates to the expectation based on the age of that specimen. The equivalent based on the Neandertal genome leads to a poorer fit. This is likely due in part to the older age of the Neandertal and the older time of the split between modern humans and Neandertals, but also due to gene flow from Neandertals to modern humans not being considered in the underlying demographic model. Thus, the incorporation of ancient DNA can improve allele age estimation, demographic modeling, and tests of natural selection. Our results also point to the importance of considering a more diverse set of ancient samples for understanding the geographic and temporal range of individual alleles.

  4. Characteristics of bone marrow-derived endothelial progenitor cells in aged mice

    SciTech Connect

    Zhang Wei; Zhang Guoping; Jin Huiming . E-mail: hmjin@shmu.edu.cn; Hu Renming

    2006-09-29

    Evidence for dysfunction of endothelial repair in aged mice was sought by studying the pattern of induced differentiation, quantity, and function of bone marrow-derived endothelial progenitor cells (EPCs) in aged mice. The CD117-positive stem cell population was separated from bone marrow by magnetic activated cell-sorting system (MACS), and EPCs were defined by demonstrating the expression of CD117{sup +}CD34{sup +}Flk-1{sup +} by flow cytometry. After 7 days of culture, the number of clones formed was counted, and proliferation and migration of EPCs were analyzed by MTT[3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide] assay and modified Boyden chamber assay. The results demonstrated that compared to the control group, the quantity of bone marrow-derived CD117{sup +} stem cells and EPCs, as well as the proliferation, migration, the number of clones formed, and phagocytotic function of EPCs were significantly reduced in aged mice. There were no significant differences in the morphology and induced differentiation pattern of EPCs between the aged mouse group and the control group. Authors suggest that the dysfunction of EPCs may serve as a surrogate parameter of vascular function in old mice.

  5. Derivation of Pluripotent Cells from Mouse SSCs Seems to Be Age Dependent

    PubMed Central

    Azizi, Hossein; Conrad, Sabine; Hinz, Ursula; Asgari, Behrouz; Nanus, Daniel; Peterziel, Heike; Hajizadeh Moghaddam, Akbar; Baharvand, Hossein; Skutella, Thomas

    2016-01-01

    Here, we aimed to answer important and fundamental questions in germ cell biology with special focus on the age of the male donor cells and the possibility to generate embryonic stem cell- (ESC-) like cells. While it is believed that spermatogonial stem cells (SSCs) and truly pluripotent ESC-like cells can be isolated from adult mice, it remained unknown if the spontaneous conversion of SSCs to ESC-like cells fails at some age. Similarly, there have been differences in the literature about the duration of cultures during which ESC-like cells may appear. We demonstrate the possibility to derive ESC-like cells from SSC cultures until they reach adolescence or up to 7 weeks of age, but we point out the impossibility to derive these cells from older, mature adult mice. The inability of real adult SSCs to shift to a pluripotent state coincides with a decline in expression of the core pluripotency genes Oct4, Nanog, and Sox2 in SSCs with age. At the same time genes of the spermatogonial differentiation pathway increase. The generated ESC-like cells were similar to ESCs and express pluripotency markers. In vitro they differentiate into all three germ lineages; they form complex teratomas after transplantation in SCID mice and produce chimeric mice. PMID:26664410

  6. Age estimation from pulp/tooth area ratio (PTR) in an Indian sample: A preliminary comparison of three mandibular teeth used alone and in combination.

    PubMed

    Babshet, Medha; Acharya, Ashith B; Naikmasur, Venkatesh G

    2011-11-01

    Pulp/tooth area ratio (PTR) method of adult dental age estimation has been examined on few tooth types. We assessed the lateral incisor (LI) and first premolar (PM1) in addition to canine (C) - alone and in combination. Periapical radiographs from 61 Indians aged 21-71 years were examined. PTR of LI produced the best age correlation (r = -0.395) followed closely by PM1 (r = -0.362). The canine revealed the lowest correlation (r = -0.206); among tooth combinations, the three teeth taken together had the best R value (-0.438) followed by LI + PM1 (-0.435), LI + C (-0.406) and C + PM1 (-0.37). The standard errors of estimates (S.E.E.) of the regression analyses for the individual teeth and tooth combinations ranged from ±12.13 to 13.08 years, indicating minimal difference in age estimates using solitary or multiple teeth. Errors were higher than in European groups (±2.5-5 years) which may partly owe to moderate age correlation of secondary dentine deposition in Indians. Moreover, facial soft-tissue superimposition in living subjects evaluated herein possibly precluded optimal tooth and pulp canal visualization. These indicate that the PTR method should be used judiciously in age estimation of living Indian adults, although further studies on larger samples with evenly distributed age-groups is necessary for deriving definitive conclusions.

  7. Weight Estimation Tool for Children Aged 6 to 59 Months in Limited-Resource Settings

    PubMed Central

    2016-01-01

    Importance A simple, reliable anthropometric tool for rapid estimation of weight in children would be useful in limited-resource settings where current weight estimation tools are not uniformly reliable, nearly all global under-five mortality occurs, severe acute malnutrition is a significant contributor in approximately one-third of under-five mortality, and a weight scale may not be immediately available in emergencies to first-response providers. Objective To determine the accuracy and precision of mid-upper arm circumference (MUAC) and height as weight estimation tools in children under five years of age in low-to-middle income countries. Design This was a retrospective observational study. Data were collected in 560 nutritional surveys during 1992–2006 using a modified Expanded Program of Immunization two-stage cluster sample design. Setting Locations with high prevalence of acute and chronic malnutrition. Participants A total of 453,990 children met inclusion criteria (age 6–59 months; weight ≤ 25 kg; MUAC 80–200 mm) and exclusion criteria (bilateral pitting edema; biologically implausible weight-for-height z-score (WHZ), weight-for-age z-score (WAZ), and height-for-age z-score (HAZ) values). Exposures Weight was estimated using Broselow Tape, Hong Kong formula, and database MUAC alone, height alone, and height and MUAC combined. Main Outcomes and Measures Mean percentage difference between true and estimated weight, proportion of estimates accurate to within ± 25% and ± 10% of true weight, weighted Kappa statistic, and Bland-Altman bias were reported as measures of tool accuracy. Standard deviation of mean percentage difference and Bland-Altman 95% limits of agreement were reported as measures of tool precision. Results Database height was a more accurate and precise predictor of weight compared to Broselow Tape 2007 [B], Broselow Tape 2011 [A], and MUAC. Mean percentage difference between true and estimated weight was +0.49% (SD = 10

  8. Twins and the paradox of dental-age estimations: a caution for researchers and clinicians.

    PubMed

    Pechníková, M; De Angelis, D; Gibelli, D; Vecchio, V; Cameriere, R; Zeqiri, B; Cattaneo, C

    2014-08-01

    The biological age difference among twins is frequently an issue in studies of genetic influence on various dental features, particularly dental development. The timing of dental development is a crucial issue also for many clinicians and researchers. The aim of this study was therefore to verify within groups of twins how dental development differs, by applying Demirjian's method, Mincer's charts of development of third molars and two of Cameriere's methods for dental age estimation, which are among the most popular methods both in the clinical and the forensic scenario. The sample consisted of 64 twin pairs: 21 monozygotic, 30 dizygotic same-sex and 13 dizygotic opposite-sex with an age range between 5.8 and 22.6 years. Dental age was determined from radiographs using the mentioned methods. Results showed that dental age of monozygotic twins is not identical even if they share all their genes. The mean intra-pair difference of monozygotic pairs was low and similar to the difference in dizygotic same-sex twins; the maximum difference between monozygotic twins, however, was surprisingly large (nearly two years). This should lead to some circumspection in the interpretation of systematic estimations of dental age both in the clinical and forensic scenario. PMID:24951409

  9. Twins and the paradox of dental-age estimations: a caution for researchers and clinicians.

    PubMed

    Pechníková, M; De Angelis, D; Gibelli, D; Vecchio, V; Cameriere, R; Zeqiri, B; Cattaneo, C

    2014-08-01

    The biological age difference among twins is frequently an issue in studies of genetic influence on various dental features, particularly dental development. The timing of dental development is a crucial issue also for many clinicians and researchers. The aim of this study was therefore to verify within groups of twins how dental development differs, by applying Demirjian's method, Mincer's charts of development of third molars and two of Cameriere's methods for dental age estimation, which are among the most popular methods both in the clinical and the forensic scenario. The sample consisted of 64 twin pairs: 21 monozygotic, 30 dizygotic same-sex and 13 dizygotic opposite-sex with an age range between 5.8 and 22.6 years. Dental age was determined from radiographs using the mentioned methods. Results showed that dental age of monozygotic twins is not identical even if they share all their genes. The mean intra-pair difference of monozygotic pairs was low and similar to the difference in dizygotic same-sex twins; the maximum difference between monozygotic twins, however, was surprisingly large (nearly two years). This should lead to some circumspection in the interpretation of systematic estimations of dental age both in the clinical and forensic scenario.

  10. Age estimation in northern Chinese children by measurement of open apices in tooth roots.

    PubMed

    Guo, Yu-Cheng; Yan, Chun-Xia; Lin, Xing-Wei; Zhou, Hong; Li, Ju-Ping; Pan, Feng; Zhang, Zhi-Yong; Wei, Lai; Tang, Zheng; Chen, Teng

    2015-01-01

    The aim of this study was to assess the accuracy of Cameriere's methods on dental age estimation in the northern Chinese population. A sample of orthopantomographs of 785 healthy children (397 girls and 388 boys) aged between 5 and 15 years was collected. The seven left permanent mandibular teeth were evaluated with Cameriere's method. The sample was split into a training set to develop a Chinese-specific prediction formula and a test set to validate this novel developed formula. Following the training dataset study, the variables gender (g), x 3 (canine teeth), x 4 (first premolar), x 7 (second molar), N 0, and the first-order interaction between s and N 0 contributed significantly to the fit, yielding the following linear regression formula: Age = 10.202 + 0.826 g - 4.068x 3 - 1.536x 4 - 1.959x 7 + 0.536 N 0 - 0.219 s [Symbol: see text] N 0, where g is a variable, 1 for boys and 0 for girls. The equation explained 91.2 % (R (2) = 0.912) of the total deviance. By analyzing the test dataset, the accuracy of the European formula and Chinese formula was determined by the difference between the estimated dental age (DA) and chronological age (CA). The European formula verified on the collected Chinese children underestimated chronological age with a mean difference of around -0.23 year, while the Chinese formula underestimated the chronological age with a mean difference of -0.04 year. Significant differences in mean differences in years (DA - CA) and absolute difference (AD) between the Chinese-specific prediction formula and Cameriere's European formula were observed. In conclusion, a Chinese-specific prediction formula based on a large Chinese reference sample could ameliorate the age prediction accuracy in the age group of children.

  11. Estimation efficiency of usage satellite derived and modelled biophysical products for yield forecasting

    NASA Astrophysics Data System (ADS)

    Kolotii, Andrii; Kussul, Nataliia; Skakun, Sergii; Shelestov, Andrii; Ostapenko, Vadim; Oliinyk, Tamara

    2015-04-01

    Efficient and timely crop monitoring and yield forecasting are important tasks for ensuring of stability and sustainable economic development [1]. As winter crops pay prominent role in agriculture of Ukraine - the main focus of this study is concentrated on winter wheat. In our previous research [2, 3] it was shown that usage of biophysical parameters of crops such as FAPAR (derived from Geoland-2 portal as for SPOT Vegetation data) is far more efficient for crop yield forecasting to NDVI derived from MODIS data - for available data. In our current work efficiency of usage such biophysical parameters as LAI, FAPAR, FCOVER (derived from SPOT Vegetation and PROBA-V data at resolution of 1 km and simulated within WOFOST model) and NDVI product (derived from MODIS) for winter wheat monitoring and yield forecasting is estimated. As the part of crop monitoring workflow (vegetation anomaly detection, vegetation indexes and products analysis) and yield forecasting SPIRITS tool developed by JRC is used. Statistics extraction is done for landcover maps created in SRI within FP-7 SIGMA project. Efficiency of usage satellite based and modelled with WOFOST model biophysical products is estimated. [1] N. Kussul, S. Skakun, A. Shelestov, O. Kussul, "Sensor Web approach to Flood Monitoring and Risk Assessment", in: IGARSS 2013, 21-26 July 2013, Melbourne, Australia, pp. 815-818. [2] F. Kogan, N. Kussul, T. Adamenko, S. Skakun, O. Kravchenko, O. Kryvobok, A. Shelestov, A. Kolotii, O. Kussul, and A. Lavrenyuk, "Winter wheat yield forecasting in Ukraine based on Earth observation, meteorological data and biophysical models," International Journal of Applied Earth Observation and Geoinformation, vol. 23, pp. 192-203, 2013. [3] Kussul O., Kussul N., Skakun S., Kravchenko O., Shelestov A., Kolotii A, "Assessment of relative efficiency of using MODIS data to winter wheat yield forecasting in Ukraine", in: IGARSS 2013, 21-26 July 2013, Melbourne, Australia, pp. 3235 - 3238.

  12. [Radiologically determined DMF index variations for forensic age estimation of young adults].

    PubMed

    Andreas, Olze; Mahlow, Andrea; Schmidt, Sven; Geserick, Gunther; Schmeling, Andreas

    2004-01-01

    The eruption and mineralization of third molars are the main criteria for dental age estimation of living people involved in criminal proceedings. Since the development of third molars is usually completed by the age of 19 or 20 years, this feature cannot be used to ascertain whether a person has attained the forensically relevant age of 21 years. This study examined whether the DMFT index or the third molar DFT index could supply reliable information enabling conclusions to be drawn about whether a person has reached the age of 21. To this end, 650 conventional orthopantomograms of German subjects aged 18 to 30 years were evaluated. The DMF index variations considered were found to be unsuitable for determining whether a person is over 21 because they displayed a weak correlation with age and considerable individual scatter. A high indicative value can only be attributed to a third molar DFT index of 4, although this is rarely observed in the relevant age group. An X-ray examination of the medial clavicular epiphyseal cartilage is, therefore, strongly recommended when assessing whether a person has attained 21 years of age.

  13. Improved methods for GRACE-derived groundwater storage change estimation in large-scale agroecosystems

    NASA Astrophysics Data System (ADS)

    Brena, A.; Kendall, A. D.; Hyndman, D. W.

    2013-12-01

    Large-scale agroecosystems are major providers of agricultural commodities and an important component of the world's food supply. In agroecosystems that depend mainly in groundwater, it is well known that their long-term sustainability can be at risk because of water management strategies and climatic trends. The water balance of groundwater-dependent agroecosystems such as the High Plains aquifer (HPA) are often dominated by pumping and irrigation, which enhance hydrological processes such as evapotranspiration, return flow and recharge in cropland areas. This work provides and validates new quantitative groundwater estimation methods for the HPA that combine satellite-based estimates of terrestrial water storage (GRACE), hydrological data assimilation products (NLDAS-2) and in situ measurements of groundwater levels and irrigation rates. The combined data can be used to elucidate the controls of irrigation on the water balance components of agroecosystems, such as crop evapotranspiration, soil moisture deficit and recharge. Our work covers a decade of continuous observations and model estimates from 2003 to 2013, which includes a significant drought since 2011. This study aims to: (1) test the sensitivity of groundwater storage to soil moisture and irrigation, (2) improve estimates of irrigation and soil moisture deficits (3) infer mean values of groundwater recharge across the HPA. The results show (1) significant improvements in GRACE-derived aquifer storage changes using methods that incorporate irrigation and soil moisture deficit data, (2) an acceptable correlation between the observed and estimated aquifer storage time series for the analyzed period, and (3) empirically-estimated annual rates of groundwater recharge that are consistent with previous geochemical and modeling studies. We suggest testing these correction methods in other large-scale agroecosystems with intensive groundwater pumping and irrigation rates.

  14. Estimating crop net primary production using national inventory data and MODIS-derived parameters

    NASA Astrophysics Data System (ADS)

    Bandaru, Varaprasad; West, Tristram O.; Ricciuto, Daniel M.; César Izaurralde, R.

    2013-06-01

    National estimates of spatially-resolved cropland net primary production (NPP) are needed for diagnostic and prognostic modeling of carbon sources, sinks, and net carbon flux between land and atmosphere. Cropland NPP estimates that correspond with existing cropland cover maps are needed to drive biogeochemical models at the local scale as well as national and continental scales. Existing satellite-based NPP products tend to underestimate NPP on croplands. An Agricultural Inventory-based Light Use Efficiency (AgI-LUE) framework was developed to estimate individual crop biophysical parameters for use in estimating crop-specific NPP over large multi-state regions. The method is documented here and evaluated for corn (Zea mays L.) and soybean (Glycine max L. Merr.) in Iowa and Illinois in 2006 and 2007. The method includes a crop-specific Enhanced Vegetation Index (EVI), shortwave radiation data estimated using the Mountain Climate Simulator (MTCLIM) algorithm, and crop-specific LUE per county. The combined aforementioned variables were used to generate spatially-resolved, crop-specific NPP that corresponds to the Cropland Data Layer (CDL) land cover product. Results from the modeling framework captured the spatial NPP gradient across croplands of Iowa and Illinois, and also represented the difference in NPP between years 2006 and 2007. Average corn and soybean NPP from AgI-LUE was 917 g C m-2 yr-1 and 409 g C m-2 yr-1, respectively. This was 2.4 and 1.1 times higher, respectively, for corn and soybean compared to the MOD17A3 NPP product. Site comparisons with flux tower data show AgI-LUE NPP in close agreement with tower-derived NPP, lower than inventory-based NPP, and higher than MOD17A3 NPP. The combination of new inputs and improved datasets enabled the development of spatially explicit and reliable NPP estimates for individual crops over large regional extents.

  15. Smoke aerosol properties and ageing effects for Northern temperate and boreal regions derived from AERONET source and age attribution

    NASA Astrophysics Data System (ADS)

    Nikonovas, Tadas; North, Peter; Doerr, Stefan H.

    2015-04-01

    Particulate emissions from wildfires impact human health and have a large but uncertain effect on climate. Modelling schemes depend on information about emission factors, emitted particle microphysical and optical properties and ageing effects, while satellite retrieval algorithms make use of characteristic aerosol models to improve retrieval. Ground based remote sensing provides detailed aerosol characterisation, but does not contain information on source. A new method is presented to estimate plume origin land cover type and age for AERONET aerosol observations, employing trajectory modelling using the HYSPLIT model, and satellite active fire and aerosol optical thickness (AOT) observations from MODIS and AATSR. It is applied to AERONET stations located in or near Northern temperate and boreal forests, for the period 2002-2013. The results from 629 fire attributions indicate significant differences insize distributions and particle optical properties between different land cover types. Smallest fine mode median radius are attributed to plumes from cropland/natural vegetation mosaic (0.143 μm) and grasslands (0.147 μm) fires. Evergreen needleleaf forest emissions show a significantly smaller fine mode median radius (0.164 μm) than plumes from woody savannas (0.184 μm) and mixed forest (0.193 μm) fires. Smoke plumes are predominantly scattering for all of the classes with median single scattering albedo at 440 nm (SSA(440)) values close to 0.95 except the cropland emissions which have SSA(440) value of 0.9. Overall fine mode volume median radius increase rate is 0.0095μm per day for the first 4 days of ageing and 0.0084 μm per day for seven days of ageing. Changes in size were consistent with a decrease in Angstrom Exponent and increase in Asymmetry parameter. No significant changes in SSA(λ) with ageing were found. The implications of this work for improved modeling of aerosol radiative effects, which are relevant to both climate modelling and satellite

  16. Smoke aerosol properties and ageing effects for northern temperate and boreal regions derived from AERONET source and age attribution

    NASA Astrophysics Data System (ADS)

    Nikonovas, T.; North, P. R. J.; Doerr, S. H.

    2015-07-01

    Particulate emissions from wildfires impact human health and have a large but uncertain effect on climate. Modelling schemes depend on information about emission factors, emitted particle microphysical and optical properties and ageing effects, while satellite retrieval algorithms make use of characteristic aerosol models to improve retrieval. Ground-based remote sensing provides detailed aerosol characterisation, but does not contain information on source. Here, a method is presented to estimate plume origin land cover type and age for AERONET aerosol observations, employing trajectory modelling using the HYSPLIT model, and satellite active fire and aerosol optical thickness (AOT) observations from Moderate Resolution Imaging Spectroradiometer (MODIS) and Along Track Scanning Radiometer (AATSR). It is applied to AERONET stations located in or near northern temperate and boreal forests for the period 2002-2013. The results from 629 fire attributions indicate significant differences in size distributions and particle optical properties between different land cover types and plume age. Smallest fine mode median radius (Rfv) are attributed to plumes from cropland and/or natural vegetation mosaic (0.143 μm) and grassland (0.157 μm) fires. North American evergreen needleleaf forest emissions show a significantly smaller Rfv (0.164 μm) than plumes from Eurasian mixed forests (0.193 μm) and plumes attributed to the land cover types with sparse tree cover - open shrubland (0.185 μm) and woody savannas (0.184 μm). The differences in size distributions are related to inferred variability in plume concentrations between the land cover types. Significant differences are observed between day and night emissions, with daytime emissions showing larger particle sizes. Smoke is predominantly scattering for all of the classes with median single scattering albedo at 440 nm (SSA(440)) values close to 0

  17. Estimating age at death using the sternal end of the fourth ribs from Mexican males.

    PubMed

    Cerezo-Román, Jessica Inés; Hernández Espinoza, Patricia Olga

    2014-03-01

    The indicators proposed by İşcan et al. (1984) are said to reflect age changes that occur in the sternal end of the fourth rib. These indicators have been used to estimate age-at-death in adult skeletal samples. However, Isçan et al. developed their methods using a forensic sample from Florida (U.S.A.). In order to test the reproducibility of those methods we evaluate its accuracy for the fourth ribs by applying it to a sample of known age and sex but of different biological affinity: modern males from Mexico City. We found that the method developed by İşcan et al. underestimates age-at-death in the Mexican sample.

  18. Age estimates of globular clusters in the Milky Way: constraints on cosmology.

    PubMed

    Krauss, Lawrence M; Chaboyer, Brian

    2003-01-01

    Recent observations of stellar globular clusters in the Milky Way Galaxy, combined with revised ranges of parameters in stellar evolution codes and new estimates of the earliest epoch of globular cluster formation, result in a 95% confidence level lower limit on the age of the Universe of 11.2 billion years. This age is inconsistent with the expansion age for a flat Universe for the currently allowed range of the Hubble constant, unless the cosmic equation of state is dominated by a component that violates the strong energy condition. This means that the three fundamental observables in cosmology-the age of the Universe, the distance-redshift relation, and the geometry of the Universe-now independently support the case for a dark energy-dominated Universe.

  19. Hierarchical Bayesian analysis to incorporate age uncertainty in growth curve analysis and estimates of age from length: Florida manatee (Trichechus manatus) carcasses

    USGS Publications Warehouse

    Schwarz, L.K.; Runge, M.C.

    2009-01-01

    Age estimation of individuals is often an integral part of species management research, and a number of ageestimation techniques are commonly employed. Often, the error in these techniques is not quantified or accounted for in other analyses, particularly in growth curve models used to describe physiological responses to environment and human impacts. Also, noninvasive, quick, and inexpensive methods to estimate age are needed. This research aims to provide two Bayesian methods to (i) incorporate age uncertainty into an age-length Schnute growth model and (ii) produce a method from the growth model to estimate age from length. The methods are then employed for Florida manatee (Trichechus manatus) carcasses. After quantifying the uncertainty in the aging technique (counts of ear bone growth layers), we fit age-length data to the Schnute growth model separately by sex and season. Independent prior information about population age structure and the results of the Schnute model are then combined to estimate age from length. Results describing the age-length relationship agree with our understanding of manatee biology. The new methods allow us to estimate age, with quantified uncertainty, for 98% of collected carcasses: 36% from ear bones, 62% from length.

  20. Estimating Allele Age and Selection Coefficient from Time-Serial Data

    PubMed Central

    Malaspinas, Anna-Sapfo; Malaspinas, Orestis; Evans, Steven N.; Slatkin, Montgomery

    2012-01-01

    Recent advances in sequencing technologies have made available an ever-increasing amount of ancient genomic data. In particular, it is now possible to target specific single nucleotide polymorphisms in several samples at different time points. Such time-series data are also available in the context of experimental or viral evolution. Time-series data should allow for a more precise inference of population genetic parameters and to test hypotheses about the recent action of natural selection. In this manuscript, we develop a likelihood method to jointly estimate the selection coefficient and the age of an allele from time-serial data. Our method can be used for allele frequencies sampled from a single diallelic locus. The transition probabilities are calculated by approximating the standard diffusion equation of the Wright–Fisher model with a one-step process. We show that our method produces unbiased estimates. The accuracy of the method is tested via simulations. Finally, the utility of the method is illustrated with an application to several loci encoding coat color in horses, a pattern that has previously been linked with domestication. Importantly, given our ability to estimate the age of the allele, it is possible to gain traction on the important problem of distinguishing selection on new mutations from selection on standing variation. In this coat color example for instance, we estimate the age of this allele, which is found to predate domestication. PMID:22851647

  1. Estimation of fracture toughness of cast stainless steels during thermal aging in LWR systems

    SciTech Connect

    Chopra, O.K. )

    1991-06-01

    A procedure and correlations are presented for predicting the change in fracture toughness of cast stainless steel components due to thermal aging during service in light water rectors (LWRs) at 280--330{degrees}C (535--625{degrees}F). The fracture toughness J-R curve and Charpy-impact energy of aged cast stainless steels are estimated from known mineral in formation. Fracture toughness of a specific cast stainless steel is estimated from the extent and kinetics of thermal embrittlement. The extent of thermal embrittlement is characterized by the room-temperature normalized'' Charpy-impact energy. A correlation for the extent of embrittlement at saturation,'' i.e., the minimum impact energy that would be achieved for the material after long-term aging, is given in terms of a material parameter, {Phi}, which is determined from the chemical composition. The fracture toughness J-R curve for the material is then obtained from correlations between room-temperature Charpy-impact energy and fracture toughness parameters. Fracture toughness as a function of time and temperature of reactor service is estimated from the kinetics of thermal embrittlement, which is determined from chemical composition. A common lower-bound'' J-R curve for cast stainless steels with unknown chemical composition is also defined for a given material specification, ferrite content, and temperature. Examples for estimating impact strength and fracture toughness of cast stainless steel components during reactor service are describes. 24 refs., 39 figs., 2 tabs.

  2. Histological estimation of age at death using microradiographs of humeral compact bone.

    PubMed

    Yoshino, M; Imaizumi, K; Miyasaka, S; Seta, S

    1994-02-01

    The purpose of this study is to develop an age estimating method for skeletal remains using microradiographs of compact bone. Compact bones of the humerus were collected from 40 Japanese males ranging from 23 to 80 years of age. Microradiographs taken from cross-sections were histomorphometrically examined by using an image analyzer. Histological parameters used in this study included 10 items, that is, osteon number, double-zoned osteon number, type II osteon number, low-density osteon number, osteon fragment number, resorption space number, total and average osteon area, and total and average Haversian canal area. The osteon fragment number showed the highest correlation coefficient with advancing age (r = 0.786). The measurement data obtained from 10 histological parameters were subjected to multiple regression analysis for producing multiple regression equations for age estimation. In practice, 8 histological parameters were selected for the equation and its multiple correlation coefficient and standard error of estimate were 0.903 and 6.1, respectively.

  3. Accurate radiocarbon age estimation using "early" measurements: a new approach to reconstructing the Paleolithic absolute chronology

    NASA Astrophysics Data System (ADS)

    Omori, Takayuki; Sano, Katsuhiro; Yoneda, Minoru

    2014-05-01

    This paper presents new correction approaches for "early" radiocarbon ages to reconstruct the Paleolithic absolute chronology. In order to discuss time-space distribution about the replacement of archaic humans, including Neanderthals in Europe, by the modern humans, a massive data, which covers a wide-area, would be needed. Today, some radiocarbon databases focused on the Paleolithic have been published and used for chronological studies. From a viewpoint of current analytical technology, however, the any database have unreliable results that make interpretation of radiocarbon dates difficult. Most of these unreliable ages had been published in the early days of radiocarbon analysis. In recent years, new analytical methods to determine highly-accurate dates have been developed. Ultrafiltration and ABOx-SC methods, as new sample pretreatments for bone and charcoal respectively, have attracted attention because they could remove imperceptible contaminates and derive reliable accurately ages. In order to evaluate the reliability of "early" data, we investigated the differences and variabilities of radiocarbon ages on different pretreatments, and attempted to develop correction functions for the assessment of the reliability. It can be expected that reliability of the corrected age is increased and the age applied to chronological research together with recent ages. Here, we introduce the methodological frameworks and archaeological applications.

  4. Estimation of lysine requirements of growing Japanese quail during the fourth and fifth weeks of age.

    PubMed

    Mehri, Mehran; Bagherzadeh Kasmani, Farzad; Asghari-Moghadam, Morteza

    2015-08-01

    A dose-response assay was conducted using broken-line regressions to estimate the lysine (Lys) requirements of quail chicks from 21 to 35 d of age. A basal diet was formulated to be adequate in all nutrients other than Lys. Incremental levels of L-Lys.HCl were added to the basal diet at the expense of a mix of cornstarch, NaHCO3, and NaCl to create 6 experimental diets containing 0.84 to 1.59% Lys. Feed intake (FI), weight gain (WG), and feed conversion ratio (FCR) responded quadratically to incremental levels of Lys (P < 0.0001). Using the linear broken-line (LBL) model, the estimated Lys requirements for WG during the fourth and fifth wk of age were 1.25 and 1.23% of diet, respectively. The corresponding values for FCR were estimated at 1.23 and 1.26% of diet, respectively. Fitting the quadratic broken-line (QBL) model, the estimated Lys requirements for WG during the fourth and fifth wk of age were 1.34 and 1.34% of diet, respectively. The corresponding values for FCR were estimated at 1.35 and 1.36% of diet, respectively. This study showed that using the QBL model as a promising way to estimate amino acids needed in the diet, the optimal Lys level to optimize performance of growing Japanese quail at the late stage of production might be 1.36% of diet, which is 105% of NRC recommendations. PMID:26069252

  5. Age estimation in children and young adolescents for forensic purposes using fourth cervical vertebra (C4).

    PubMed

    Cameriere, R; Giuliodori, A; Zampi, M; Galić, I; Cingolani, M; Pagliara, F; Ferrante, L

    2015-03-01

    The aim of this study was to evaluate the applicability of using the growth of the body of C4 vertebra for the estimation of age in children and young adolescents. We used the fact that the proportions between the radiologic projections of the posterior and anterior sides of the C4 vertebral body, which forms a trapezoidal shape, differ with age: in younger individuals, the posterior side is higher, whereas in older individuals, the projections of the sides of the vertebral body form a rectangular shape with the two sides equal or with the anterior side slightly higher. Cephalograms of 444 Italian subjects (214 female and 230 male individuals) aged between 5 and 15 years and with no obvious development abnormalities were analyzed. The projections of the anterior side (a) and of the posterior side (b) of each C4 body were measured, and their ratio (Vba), as a value of the C4 body development, was used for age estimation. Distribution of the Vba suggested that it does not change after 13 years in female and 14 years in male subjects. Consequently, we restricted our analysis of the Vba growing model until 14 years in both sexes. We used a Bayesian calibration method to estimate chronological age as function of Vba as a predicting variable. The intra- and inter-observer agreement was satisfactory, using intra-class correlation coefficient of Vba on 30 randomly selected cephalograms. The mean absolute errors were 1.34 years (standard deviation 0.95) and 1.01 years (standard deviation 0.71), and the mean inter-quartile ranges of the calibrating distribution were 2.32 years (standard deviation 0.25) in male and 1.72 years (standard deviation 0.39) in female individuals, respectively. The slopes of the regression of the estimated age error to chronological age were 0.02 in male and 0.06 in female individuals, where both values did not result significantly different from 0 (p > 0.12). In conclusion, although our Bayesian calibration method might not really

  6. The biochemical estimation of age in Euphausiids: Laboratory calibration and field comparisons

    NASA Astrophysics Data System (ADS)

    Harvey, H. R.; Ju, Se-J.; Son, S.-K.; Feinberg, L. R.; Shaw, C. T.; Peterson, W. T.

    2010-04-01

    Euphausiids play a key role in many marine ecosystems as a link between primary producers and top predators. Understanding their demographic (i.e. age) structure is an essential tool to assess growth and recruitment as well as to determine how changes in environmental conditions might alter their condition and distribution. Age determination of crustaceans cannot be accomplished using traditional approaches, and here we evaluate the potential for biochemical products of tissue metabolism (termed lipofuscins) to determine the demographic structure of euphausiids in field collections . Lipofuscin was extracted from krill neural tissues (eye and eye-stalk), quantified using fluorescent intensity and normalized to tissue protein content to allow comparisons across animal sizes. Multiple fluorescent components from krill were observed, with the major product having a maximum fluorescence at excitation of 355 nm and emission of 510 nm. Needed age calibration of lipofuscin accumulation in Euphausia pacifica was accomplished using known-age individuals hatched and reared in the laboratory for over one year. Lipofuscin content extracted from neural tissues of laboratory-reared animals was highly correlated with the chronological age of animals ( r=0.87). Calibrated with laboratory lipofuscin accumulation rates, field-collected sub-adult and adult E. pacifica in the Northeast Pacific were estimated to be older than 100 days and younger than 1year. Comparative data for the Antarctic krill, E. superba showed much higher lipofuscin values suggesting a much longer lifespan than the more temperate species, E. pacifica. These regional comparisons suggest that biochemical indices allow a practical approach to estimate population age structure of diverse populations, and combined with other measurements can provide estimates of vital rates (i.e. longevity, mortality, growth) for krill populations in dynamic environments.

  7. Application of age estimation methods based on teeth eruption: how easy is Olze method to use?

    PubMed

    De Angelis, D; Gibelli, D; Merelli, V; Botto, M; Ventura, F; Cattaneo, C

    2014-09-01

    The development of new methods for age estimation has become with time an urgent issue because of the increasing immigration, in order to estimate accurately the age of those subjects who lack valid identity documents. Methods of age estimation are divided in skeletal and dental ones, and among the latter, Olze's method is one of the most recent, since it was introduced in 2010 with the aim to identify the legal age of 18 and 21 years by evaluating the different stages of development of the periodontal ligament of the third molars with closed root apices. The present study aims at verifying the applicability of the method to the daily forensic practice, with special focus on the interobserver repeatability. Olze's method was applied by three different observers (two physicians and one dentist without a specific training in Olze's method) to 61 orthopantomograms from subjects of mixed ethnicity aged between 16 and 51 years. The analysis took into consideration the lower third molars. The results provided by the different observers were then compared in order to verify the interobserver error. Results showed that interobserver error varies between 43 and 57 % for the right lower third molar (M48) and between 23 and 49 % for the left lower third molar (M38). Chi-square test did not show significant differences according to the side of teeth and type of professional figure. The results prove that Olze's method is not easy to apply when used by not adequately trained personnel, because of an intrinsic interobserver error. Since it is however a crucial method in age determination, it should be used only by experienced observers after an intensive and specific training.

  8. Derivative Spectrophotometric Method for Estimation of Antiretroviral Drugs in Fixed Dose Combinations

    PubMed Central

    P.B., Mohite; R.B., Pandhare; S.G., Khanage

    2012-01-01

    Purpose: Lamivudine is cytosine and zidovudine is cytidine and is used as an antiretroviral agents. Both drugs are available in tablet dosage forms with a dose of 150 mg for LAM and 300 mg ZID respectively. Method: The method employed is based on first order derivative spectroscopy. Wavelengths 279 nm and 300 nm were selected for the estimation of the Lamovudine and Zidovudine respectively by taking the first order derivative spectra. The conc. of both drugs was determined by proposed method. The results of analysis have been validated statistically and by recovery studies as per ICH guidelines. Result: Both the drugs obey Beer’s law in the concentration range 10-50 μg mL-1,for LAM and ZID; with regression 0.9998 and 0.9999, intercept – 0.0677 and – 0.0043 and slope 0.0457 and 0.0391 for LAM and ZID, respectively.The accuracy and reproducibility results are close to 100% with 2% RSD. Conclusion: A simple, accurate, precise, sensitive and economical procedures for simultaneous estimation of Lamovudine and Zidovudine in tablet dosage form have been developed. PMID:24312779

  9. Significance of apparent discrepanices in water ages derived from atmospheric radionuclides at Yucca Mountain, Nevada

    SciTech Connect

    Liu, B.; Fabryka-Martin, J.; Wolfsberg, A.; Robinson, B.; Sharma, P.

    1995-02-23

    Cosmogenic {sup 36}Cl and {sup 14}C produced in the atmosphere are being used to estimate water residence times in the unsaturated zone at Yucca Mountain. Results thus far show a systematic discordance in that {sup 14}C-based ages are generally one to two orders of magnitude younger than {sup 36}Cl-based ages. This lack of concordance probably arises from one or more of the following reasons: (1) different transport mechanisms, e.g., vapor transport for {sup 14}C; (2) different magnitudes and timing of bomb-pulse signals; (3) mixing of waters from different flow paths; and (4) possibly inadequate methods for correcting for the effect of sample contamination by carbon or chlorine from sources other than the infiltrating water. Preliminary numerical simulation results using the FEHMN code suggest that spatial variation in infiltration rates can enhance lateral flow and mixing that leads to discordance in apparent ages depending on the dating technique. Examples are presented to show that disparate radiometric ages are inevitable and to be expected where mixing of waters of markedly different ages occurs.

  10. Uncertainty in age-specific harvest estimates and consequences for white-tailed deer management

    USGS Publications Warehouse

    Collier, B.A.; Krementz, D.G.

    2007-01-01

    age classes. Thus, we suggest that using harvest proportions for management planning and evaluation should be viewed with caution. In addition, we recommend that managers focus more attention on estimation of age-specific harvest rates, and modeling approaches which combine harvest rates with information from harvested individuals to further increase their ability to effectively manage deer populations under selective harvest programs. ?? 2006 Elsevier B.V. All rights reserved.

  11. Estimating brain age using high-resolution pattern recognition: Younger brains in long-term meditation practitioners.

    PubMed

    Luders, Eileen; Cherbuin, Nicolas; Gaser, Christian

    2016-07-01

    Normal aging is known to be accompanied by loss of brain substance. The present study was designed to examine whether the practice of meditation is associated with a reduced brain age. Specific focus was directed at age fifty and beyond, as mid-life is a time when aging processes are known to become more prominent. We applied a recently developed machine learning algorithm trained to identify anatomical correlates of age in the brain translating those into one single score: the BrainAGE index (in years). Using this validated approach based on high-dimensional pattern recognition, we re-analyzed a large sample of 50 long-term meditators and 50 control subjects estimating and comparing their brain ages. We observed that, at age fifty, brains of meditators were estimated to be 7.5years younger than those of controls. In addition, we examined if the brain age estimates change with increasing age. While brain age estimates varied only little in controls, significant changes were detected in meditators: for every additional year over fifty, meditators' brains were estimated to be an additional 1month and 22days younger than their chronological age. Altogether, these findings seem to suggest that meditation is beneficial for brain preservation, effectively protecting against age-related atrophy with a consistently slower rate of brain aging throughout life. PMID:27079530

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

    PubMed

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

    2015-09-01

    The purpose of this study was to evaluate the correlation between chronological age and the degree of third molar mineralization by Demirjian's developmental stages (Demirjian et al., 1973) using panoramic radiography. From a total of 11.396 digital panoramic radiographs of patients from three oral radiology private clinics from the northeast region of Brazil, obtained from January to June 2009, 2097 radiographic images from patients aged between 6 and 22 years were selected. The images were analyzed individually by two obsevers using a 21-inch computer screen and Windows Picture and Fax Viewer. Reliability was achieved by intra- and interobserver evaluation, using the Kappa test. Chronological age, calcification stage, gender and third molar were interrelated using a multiple linear regression model, considering age as a response variable. There was reliability with Demirjian et al.'s developmental stage assesment, displaying a significant relationship between mineralization stages and patients' age (P<0.05). There was no significant difference between the average age and the calcification stage taking gender and localization of the third molar into consideration. It is possible to estimate chronological age based on Demirjian's stage of a third molar, regardless of gender and location.

  13. AN EVALUATION OF TWO GROUND-BASED CROWN CLOSURE ESTIMATION TECHNIQUES COMPARED TO CROWN CLOSURE ESTIMATES DERIVED FROM HIGH RESOLUTION IMAGERY

    EPA Science Inventory

    Two ground-based canopy closure estimation techniques, the Spherical Densitometer (SD) and the Vertical Tube (VT), were compared for the effect of deciduous understory on dominant/co-dominant crown closure estimates in even-aged loblolly (Pinus taeda) pine stands located in the N...

  14. AN EVALUATION OF TWO GROUND-BASED CROWN CLOSURE ESTIMATION TECHNIQUES COMPARED TO CROWN CLOSURE ESTIMATES DERIVED FROM HIGH RESOLUTION IMAGERY

    EPA Science Inventory

    Two ground-based canopy closure estimation techniques, the Spherical Densitometer (SD) and the Vertical Tube (VT), were compared for the effect of deciduous understory on dominantlco-dominant crown closure estimates in even-aged loblolly (Pinus taeda) pine stands located in the N...

  15. Age estimation of a large bighead carp from Grand Lake, Oklahoma

    USGS Publications Warehouse

    Long, James M.; Nealis, Ashley

    2011-01-01

    On April 23, 2011, a 1356-mm total length (TL), 39.8 kg bighead carp (Hypophthalmichthys nobilis) was brought to the Oklahoma Department of Wildlife Conservation. This specimen is the largest bighead carp recorded from Oklahoma, and it is near the maximum size reported from the United States. This specimen was estimated to be nine years old based on estimates from three different structures (pectoral fin ray, branchiostegal ray, and otolith). The age, together with past Oklahoma records of the species, indicates that there has been multiple introductions or undocumented reproduction of bighead carp in the Grand Lake basin.

  16. Parameter estimation using carbon-14 ages: Lessons from the Danube-Tisza interfluvial region of Hungary

    USGS Publications Warehouse

    Sanford, W.E.; Deak, J.; Revesz, K.

    2002-01-01

    Parameter estimation was conducted on a groundwater model of the Danube-Tisza interfluvial region of Hungary. The model was calibrated using 300 water levels and 48 14C ages. The model provided a test of regression methods for a system with a large number of observations. Up to 103 parameters representing horizontal and vertical hydraulic conductivities and boundary conductances were assigned using point values and bilinear interpolation between points. The lowest errors were obtained using an iterative approach with groups of parameters, rather than estimating all of the parameters simultaneously. The model with 48 parameters yielded the lowest standard error of regression.

  17. Quantile estimation to derive optimized test thresholds for random field statistics.

    PubMed

    Hinrichs, H; Scholz, M; Noesselt, T; Heinze, H J

    2005-08-01

    We present a numerical method to estimate the true threshold values in random fields needed to determine the significance of apparent signals observed in noisy images. To accomplish this, a quantile estimation algorithm is applied to derive the threshold with a predefined confidence interval from a large number of simulated random fields. Also, a computationally efficient method for generating a random field simulation is presented using resampling techniques. Applying these techniques, thresholds have been determined for a large variety of parameter settings (smoothness, voxel size, brain shape, type of statistics). By means of interpolation techniques, thresholds for additional arbitrary settings can be quickly derived without the need to run individual simulations. Compared to the parametric approach of Worsley et al. (1996) (Worsley, K.J., Marrett, S., Neelin P., Vandal, A.C., Friston, K.J., Evans, A.C., 1996. A unified statistical approach for determining significant signals in images of cerebral activation. Hum. Brain Mapp. 4, 58-73) and Friston et al. (1991) (Friston, K.J., Frith, C.D., Liddle, P.F., Frackowiak, R.S. 1991. Comparing functional (PET) images: the assessment of significant change. J. Cereb. Blood Flow Metab. 11(4), 690-699), and to the Bonferroni approach, these optimized thresholds lead to higher levels of significance (i.e., lower p values) with a specific amount of activation especially with fields of moderate smoothness (i.e., with a relative full width half maximum between 2 and 6). Alternatively, the threshold for a specified level of significance can be lowered. This improved statistical sensitivity is illustrated by the analysis of an actual event related functional magnetic resonance data set, and its limitations are tested by determining the false positive rate with experimental MR noise data. The grid of estimated threshold values as well as the interpolation algorithm to derive thresholds for arbitrary parameter settings are made

  18. Site-occupancy distribution modeling to correct population-trend estimates derived from opportunistic observations

    USGS Publications Warehouse

    Kery, M.; Royle, J. Andrew; Schmid, Hans; Schaub, M.; Volet, B.; Hafliger, G.; Zbinden, N.

    2010-01-01

    Species' assessments must frequently be derived from opportunistic observations made by volunteers (i.e., citizen scientists). Interpretation of the resulting data to estimate population trends is plagued with problems, including teasing apart genuine population trends from variations in observation effort. We devised a way to correct for annual variation in effort when estimating trends in occupancy (species distribution) from faunal or floral databases of opportunistic observations. First, for all surveyed sites, detection histories (i.e., strings of detection-nondetection records) are generated. Within-season replicate surveys provide information on the detectability of an occupied site. Detectability directly represents observation effort; hence, estimating detectablity means correcting for observation effort. Second, site-occupancy models are applied directly to the detection-history data set (i.e., without aggregation by site and year) to estimate detectability and species distribution (occupancy, i.e., the true proportion of sites where a species occurs). Site-occupancy models also provide unbiased estimators of components of distributional change (i.e., colonization and extinction rates). We illustrate our method with data from a large citizen-science project in Switzerland in which field ornithologists record opportunistic observations. We analyzed data collected on four species: the widespread Kingfisher (Alcedo atthis. ) and Sparrowhawk (Accipiter nisus. ) and the scarce Rock Thrush (Monticola saxatilis. ) and Wallcreeper (Tichodroma muraria. ). Our method requires that all observed species are recorded. Detectability was <1 and varied over the years. Simulations suggested some robustness, but we advocate recording complete species lists (checklists), rather than recording individual records of single species. The representation of observation effort with its effect on detectability provides a solution to the problem of differences in effort encountered

  19. Age estimation and the developing third molar tooth: an analysis of an Australian population using computed tomography.

    PubMed

    Bassed, Richard B; Briggs, C; Drummer, Olaf H

    2011-09-01

    The third molar tooth is one of the few anatomical sites available for age estimation of unknown age individuals in the late adolescent years. Computed tomography (CT) images were assessed in an Australian population aged from 15 to 25 years for development trends, particularly concerning age estimation at the child/adult transition point of 18 years. The CT images were also compared to conventional radiographs to assess the developmental scoring agreement between the two and it was found that agreement of Demirjian scores between the two imaging modalities was excellent. The relatively wide age ranges (mean ± 2SD) indicate that the third molar is not a precise tool for age estimation (age ranges of 3-8 years) but is, however, a useful tool for discriminating the adult/child transition age of 18 years. In the current study 100% of females and 96% of males with completed roots were over 18 years of age.

  20. Deriving theoretical boundaries to address scale dependencies of triangle models for evapotranspiration estimation

    NASA Astrophysics Data System (ADS)

    Long, Di; Singh, Vijay P.; Scanlon, Bridget R.

    2012-03-01

    Satellite-based triangle models for evapotranspiration estimation are unique in interpreting the relationship between the normalized difference vegetation index (NDVI)/factional vegetation cover (fc) and surface radiative temperature (Trad) across large heterogeneous areas. However, output and performance of triangle models may depend on the size of the domain being studied and resolution of the satellite images being used. The objective of this study was to assess domain and resolution dependencies of triangle models using progressively larger domains and Landsat Thematic Mapper/Enhanced Thematic Mapper Plus and Moderate Resolution Imaging Spectroradiometer sensors at the Soil Moisture-Atmosphere Coupling Experiment site in central Iowa on days of year 174 and 182 in 2002. Results show domain and resolution dependencies of the triangle models with large uncertainties in evaporative fraction (EF) estimates in terms of a mean absolute percentage difference (MAPD) up to ˜50%. A trapezoid model which requires derivation of theoretical limiting edges of the NDVI-Trad space is proposed to constrain domain and resolution dependencies of triangle models. The theoretical warm edge can be derived by solving for temperatures of the driest bare surface and the fully vegetated surface with the largest water stress implicit in both radiation budget and energy balance equations. Areal average air temperature can be taken as the theoretical cold edge. The triangle model appears to perform well across large areas (˜104 km2) but fails to predict EF over small areas (˜102 km2). The trapezoid model can effectively reduce domain and resolution dependencies and constrain errors of the EF estimates with an MAPD of ˜10%.

  1. Quantification of uncertainty in aboveground biomass estimates derived from small-footprint LiDAR data

    NASA Astrophysics Data System (ADS)

    Xu, Q.; Greenberg, J. A.; Li, B.; Ramirez, C.; Balamuta, J. J.; Evans, K.; Man, A.; Xu, Z.

    2015-12-01

    A promising approach to determining aboveground biomass (AGB) in forests comes through the use of individual tree crown delineation (ITCD) techniques applied to small-footprint LiDAR data. These techniques, when combined with allometric equations, can produce per-tree estimates of AGB. At this scale, AGB estimates can be quantified in a manner similar to how ground-based forest inventories are produced. However, these approaches have significant uncertainties that are rarely described in full. Allometric equations are often based on species-specific diameter-at-breast height (DBH) relationships, but neither DBH nor species can be reliably determined using remote sensing analysis. Furthermore, many approaches to ITCD only delineate trees appearing in the upper canopy so subcanopy trees are often missing from the inventories. In this research, we performed a propagation-of-error analysis to determine the spatially varying uncertainties in AGB estimates at the individual plant and stand level for a large collection of LiDAR acquisitions covering a large portion of California. Furthermore, we determined the relative contribution of various aspects of the analysis towards the uncertainty, including errors in the ITCD results, the allometric equations, the taxonomic designation, and the local biophysical environment. Watershed segmentation was used to obtain the preliminary crown segments. Lidar points within the preliminary segments were extracted to form profiling data of the segments, and then mode detection algorithms were applied to identify the tree number and tree heights within each segment. As part of this analysis, we derived novel "remote sensing aware" allometric equations and their uncertainties based on three-dimensional morphological metrics that can be accurately derived from LiDAR data.

  2. Protein-bound advanced glycation endproducts (AGEs) as bioactive amino acid derivatives in foods.

    PubMed

    Henle, T

    2005-12-01

    The Maillard reaction or nonenzymatic browning is of outstanding importance for the formation of flavour and colour of heated foods. Corresponding reactions, also referred to as "glycation", are known from biological systems, where the formation of advanced glycation endproducts (AGEs) shall play an important pathophysiological role in diabetes and uremia. In this review, pathways leading to the formation of individual protein-bound lysine and arginine derivatives in foods are described and nutritional consequences resulting from this posttranslational modifications of food proteins are discussed. PMID:15997413

  3. Monte Carlo simulations for deriving the precision in GPR velocity estimates

    NASA Astrophysics Data System (ADS)

    Clark, R. A.; Booth, A.; Murray, T.

    2010-12-01

    Models of ground penetrating radar (GPR) propagation velocity are often used to quantify physical subsurface properties (e.g., layer thickness, porosity, water content). A common approach is to conduct semblance analysis on common midpoint (CMP) gathers, in which successive pairs of stacking velocity and travel-time are input to Dix’s Equation, to obtain a velocity estimate, termed interval stacking velocity. However, the precision in interval stacking velocity is seldom reported since it is cumbersome to obtain an analytic expression for precision particularly since Dix’s Equation has four independently resolved degrees of freedom. We present Monte Carlo simulations as a means of expressing interval stacking velocities, and its derivative quantities, as a probability density functions (PDFs). These are built using Gaussian distributions of pseudo-random samples from within the 50% contour around successive coherence responses; precision is summarised using the median and inter-quartile range of each PDF. To verify this method’s accuracy, we simulate CMP data in which travel-times are computed for reflections from two horizontal horizons at depths of 5 and 10 m, with isotropic interval velocity of 0.1 m/ns, for source-receiver offsets from 0 to 30 m. The Monte Carlo simulation produces 107 manifestations of interval stacking velocity and layer thickness, and yields estimates of 0.1±0.003 m/ns and 4.99±0.16 m, respectively. The simulation is repeated for real CMP data, acquired with 50 MHz antennas, for establishing the precision in interval stacking velocity and speculative estimates (in the absence of extensive borehole logs) of layer thickness and fractional porosity (via the complex refractive index method, CRIM). The site comprises Quaternary sediment, in which the water table is observed at ~2 m depth, overlying Cambrian basement at 10-15 m depth. The resolution of stacking velocity in semblance analysis decreases with depth, as reflected in PDFs of

  4. Why Was Kelvin's Estimate of the Earth's Age Wrong?

    ERIC Educational Resources Information Center

    Lovatt, Ian; Syed, M. Qasim

    2014-01-01

    This is a companion to our previous paper in which we give a published example, based primarily on Perry's work, of a graph of ln "y" versus "t" when "y" is an exponential function of "t". This work led us to the idea that Lord Kelvin's (William Thomson's) estimate of the Earth's age was…

  5. Estimated incidence of pertussis in people aged <50 years in the United States

    PubMed Central

    Chen, Chi-Chang; Balderston McGuiness, Catherine; Krishnarajah, Girishanthy; Blanchette, Christopher M.; Wang, Yuanyuan; Sun, Kainan; Buck, Philip O.

    2016-01-01

    ABSTRACT The introduction of pertussis vaccination in the United States (US) in the 1940s has greatly reduced its burden. However, the incidence of pertussis is difficult to quantify, as many cases are not laboratory-confirmed or reported, particularly in adults. This study estimated pertussis incidence in a commercially insured US population aged <50 years. Data were extracted from IMS' PharMetrics Plus claims database for patients with a diagnosis of pertussis or cough illness using International Classification of Diseases (ICD-9) codes, a commercial outpatient laboratory database for patients with a pertussis laboratory test, and the Centers for Disease Control influenza surveillance database. US national pertussis incidence was projected using 3 methods: (1) diagnosed pertussis, defined as a claim for pertussis (ICD-9 033.0, 033.9, 484.3) during 2008–2013; (2) based on proxy pertussis predictive logistic regression models; (3) using the fraction of cough illness (ICD-9 033.0, 033.9, 484.3, 786.2, 466.0, 466.1, 487.1) attributed to laboratory-confirmed pertussis, estimated by time series linear regression models. Method 1 gave a projected annual incidence of diagnosed pertussis of 9/100,000, which was highest in those aged <1 year. Method 2 gave an average annual projected incidence of 21/100,000. Method 3 gave an overall regression-estimated weighted annual incidence of pertussis of 649/100,000, approximately 58–93 times higher than method 1 depending on the year. These estimations, which are consistent with considerable underreporting of pertussis in people aged <50 years and provide further evidence that the majority of cases go undetected, especially with increasing age, may aid in the development of public health programs to reduce pertussis burden. PMID:27246119

  6. Striking effect of time variation in the estimation of groundwater age in the Wairarapa valley

    NASA Astrophysics Data System (ADS)

    Petrus, Karine; Toews, Michael; Daughney, Christopher; Cornaton, Fabien

    2014-05-01

    The Wairarapa Valley exhibits complex interactions between its rivers and shallow aquifers. With agriculture being an essential part of the region the risk of contamination and depletion of groundwater exists. In order to assist with water resource management in the region, we can do predictions with the help of numerical models. Among these predictions, the evaluation of groundwater age is critical for decision making. This project builds on work done by Greater Wellington Regional Council and will focus on the Wairarapa Valley. The aim of this study is to evaluate the age of the groundwater in the Wairarapa region. Investigations have already been done thanks to hydrochemistry. However radiometric age can be misleading in the sense that it does not consider the mixing process in the motion of groundwater particules. Therefore another approach can be considered .This latter is physic based by considering the age as a property that we transport through two main processes: advection at a macroscopic scale and diffusion at a microscopic scale. The determination of the distribution age by this approach has already been done for the Lake Rotorua but in the steady state case (cf Daughney). The unique contribution of the present study is to estimate the changes in groundwater age distribution through time within the region. Indeed transient simulations are needed to explicitly account for seasonally variable rainfall and pumping wells. This affects the simulated flow solution and then the simulated age solution. In order to solve numerically the transport of age distribution we have chosen to use the Time Marching Laplace Transform Galerkin technique which has been developed in a research code by Fabien Cornaton. The obtained results depict that temporal variations in groundwater age are present and have important implication for resource management

  7. New age estimates for the Palaeolithic assemblages and Pleistocene succession of Casablanca, Morocco

    NASA Astrophysics Data System (ADS)

    Rhodes, E. J.; Singarayer, J. S.; Raynal, J.-P.; Westaway, K. E.; Sbihi-Alaoui, F. Z.

    2006-10-01

    Marine and aeolian Quaternary sediments from Casablanca, Morocco were dated using the optically stimulated luminescence (OSL) signal of quartz grains. These sediments form part of an extensive succession spanning the Pleistocene, and contain a rich faunal and archaeological record, including an Acheulian lithic assemblage from before the Brunhes-Matayama boundary, and a Homo erectus jaw from younger cave deposits. Sediment samples from the sites of Reddad Ben Ali, Oulad J'mel, Sidi Abderhamane and Thomas Quarries have been dated, in order to assess the upper limits of OSL. The revision of previously measured mammalian tooth enamel electron spin resonance (ESR) dates from the Grotte des Rhinocéros, Oulad Hamida Quarry 1, incorporating updated environmental dose rate measurements and attenuation calculations, also provide chronological constraint for the archaeological material preserved at Thomas Quarries. Several OSL age estimates extend back to around 500,000 years, with a single sample providing an OSL age close to 1 Ma in magnetically reversed sediments. These luminescence dates are some of the oldest determined, and their reliability is assessed using both internal criteria based on stratigraphic consistency, and external lithostratigraphic, morphostratigraphic and independent chronological constraints. For most samples, good internal agreement is observed using single aliquot regenerative-dose OSL measurements, while multiple aliquot additive-dose measurements generally have poorer resolution and consistency. Novel slow-component and component-resolved OSL approaches applied to four samples provide significantly enhanced dating precision, and an examination of the degree of signal zeroing at deposition. A comparison of the OSL age estimates with the updated ESR dates and one U-series date demonstrate that this method has great potential for providing reliable age estimates for sediments of this antiquity. We consider the cause of some slight age inversion

  8. Age and growth of round gobies in Lake Michigan, with preliminary mortality estimation

    USGS Publications Warehouse

    Huo, Bin; Madenjian, Charles P.; Xie, Cong X.; Zhao, Yingming; O'Brien, Timothy P.; Czesny, Sergiusz J.

    2015-01-01

    The round goby (Neogobius melanostomus) is a prevalent invasive species throughout Lake Michigan, as well as other Laurentian Great Lakes, yet little information is available on spatial variation in round goby growth within one body of water. Age and growth of round goby at three areas of Lake Michigan were studied by otolith analysis from a sample of 659 specimens collected from 2008 to 2012. Total length (TL) ranged from 48 to 131 mm for Sturgeon Bay, from 50 to 125 mm for Waukegan, and from 54 to 129 mm for Sleeping Bear Dunes. Ages ranged from 2 to 7 years for Sturgeon Bay, from 2 to 5 years for Waukegan, and from 2 to 6 years for Sleeping Bear Dunes. Area-specific and sex-specific body–otolith relationships were used to back-calculate estimates of total length at age, which were fitted to von Bertalanffy models to estimate growth rates. For both sexes, round gobies at Sleeping Bear Dunes and Waukegan grew significantly faster than those at Sturgeon Bay. However, round goby growth did not significantly differ between Sleeping Bear Dunes and Waukegan for either sex. At all three areas of Lake Michigan, males grew significantly faster than females. Based on catch curve analysis, estimates of annual mortality rates ranged from 0.79 to 0.84. These relatively high mortality rates suggested that round gobies may be under predatory control in Lake Michigan.

  9. Dental maturity curves in Finnish children: Demirjian's method revisited and polynomial functions for age estimation.

    PubMed

    Chaillet, Nils; Nyström, Marjatta; Kataja, Matti; Demirjian, Arto

    2004-11-01

    Dental maturity was studied from 2213 dental panoramic radiographs of healthy ethnic Finns from southern Finland, aged between 2 and 19 years. The aim was to provide new Finnish maturity tables and curves and to compare the efficiency of Demirjian's method when differently weighted scores and polynomial regressions are used. The inter-ethnic variations lead us to calculate specific Finnish weighted scores. Demirjian's method gives maturity score as a function of age and seems better adapted for clinicians because, in their case, the maturity score is unknown. Polynomial functions give age as a function of maturity score and are statically adapted for age estimation studies. Finnish dental maturity tables and development curves are given for Demirjian's method and for polynomial functions. Sexual dimorphism is established for the same weighted score for girls and boys, and girls present a greater maturity than boys for all of age groups. Polynomial functions are highly reliable (0.19% of misclassifies) and the percentile method, using Finnish weighted scores, is very accurate (+/- 1.95 years on average, between 2 and 18 years of age). This suggests that polynomial functions are most useful in forensic sciences, while Demirjian's method is most useful for dental health clinicians.

  10. Exfoliative cytology: A possible tool in age estimation in forensic odontology

    PubMed Central

    Shetty, Devi Charan; Wadhwan, Vijay; Khanna, Kaveri Surya; Jain, Anshi; Gupta, Amit

    2015-01-01

    Introduction: Age determination of unknown human bodies is important in the setting of a crime investigation or a mass disaster because the age at death, birth date, and year of death as well as gender can guide investigators to the correct identity among a large number of possible matches. Objective: The study was undertaken with an aim to estimate the age of an individual from their buccal smears by comparing the average cell size using image analysis morphometric software. Materials and Methods: Buccal smears were collected from 100 apparently healthy individuals. After fixation in 95% alcohol, the smears were stained using standard Papanicolaou laboratory procedure. The average cell size was measured using Dewinter's image analysis software version 4.3. Statistical analysis of the data was done using one-way ANOVA, Bonferroni procedures. Results: The results showed significant decrease in average cell size of individual with increase in age. The difference was highly significant in age group of above 60 years. Conclusion: Age-related alterations are observed in buccal smears. PMID:25709323

  11. Estimating dose rates to organs as a function of age following internal exposure to radionuclides

    SciTech Connect

    Leggett, R.W.; Eckerman, K.F.; Dunning, D.E. Jr.; Cristy, M.; Crawford-Brown, D.J.; Williams, L.R.

    1984-03-01

    The AGEDOS methodology allows estimates of dose rates, as a function of age, to radiosensitive organs and tissues in the human body at arbitrary times during or after internal exposure to radioactive material. Presently there are few, if any, radionuclides for which sufficient metabolic information is available to allow full use of all features of the methodology. The intention has been to construct the methodology so that optimal information can be gained from a mixture of the limited amount of age-dependent, nuclide-specific data and the generally plentiful age-dependent physiological data now available. Moreover, an effort has been made to design the methodology so that constantly accumulating metabolic information can be incorporated with minimal alterations in the AGEDOS computer code. Some preliminary analyses performed by the authors, using the AGEDOS code in conjunction with age-dependent risk factors developed from the A-bomb survivor data and other studies, has indicated that the doses and subsequent risks of eventually experiencing radiogenic cancers may vary substantially with age for some exposure scenarios and may be relatively invariant with age for other scenarios. We believe that the AGEDOS methodology provides a convenient and efficient means for performing the internal dosimetry.

  12. Estimation of forensic age using substages of ossification of the medial clavicle in living individuals.

    PubMed

    Ekizoglu, Oguzhan; Hocaoglu, Elif; Inci, Ercan; Can, Ismail Ozgur; Aksoy, Sema; Sayin, Ibrahim

    2015-11-01

    Forensic age estimation based on staging of ossification of the medial clavicular bone is one of the methods recommended by the Study Group on Forensic Age Diagnostics of the German Association of Forensic Medicine. In the present study, we analyzed the stages of ossification of the medial clavicular epiphyses on thin-sliced (1 mm) computed tomography (CT) images using the substages defined within stages 2 and 3. The retrospective CT analysis involved 193 subjects (129 males, 64 females) ranging in age from 13 to 28 years. Spearman's correlation analysis revealed a positive correlation between age and ossification stage in both male and female subjects. Stage 3c was first observed at 19 years of age in both sexes and may thus serve as a valuable forensic marker for determining an age of 18 years. Although further research is needed on the ossification stages of the medial clavicular epiphyses, the present findings could contribute to existing reports on observers' experiences using CT analysis of ossification combined with analysis of substages.

  13. Age estimation in an Indian population using pulp/tooth volume ratio of mandibular canines obtained from cone beam computed tomography.

    PubMed

    Jagannathan, N; Neelakantan, P; Thiruvengadam, C; Ramani, P; Premkumar, P; Natesan, A; Herald, J S; Luder, H U

    2011-07-01

    The present study assessed the suitability of pulp/tooth volume ratio of mandibular canines for age prediction in an Indian population. Volumetric reconstruction of scanned images of mandibular canines from 140 individuals (aged ten - 70 years), using computed tomography was used to measure pulp and tooth volumes. Age calculated using a formula reported earlier for a Belgian sample, resulted in errors > ten years in almost 86% of the study population. The regression equation obtained for the Indian population: Age = 57.18 + (- 413.41 x pulp/tooth volume ratio), was applied to an independent control group (n = 48), and this resulted in mean absolute errors of 8.54 years which was significantly (p < 0.05) lower than those derived with the Belgian formula. The pulp/tooth volume ratio is a useful indicator of age, although correlations may vary in different populations and hence, specific formulae should be applied for the estimates. PMID:21841263

  14. Methods for the quantitative comparison of molecular estimates of clade age and the fossil record.

    PubMed

    Clarke, Julia A; Boyd, Clint A

    2015-01-01

    Approaches quantifying the relative congruence, or incongruence, of molecular divergence estimates and the fossil record have been limited. Previously proposed methods are largely node specific, assessing incongruence at particular nodes for which both fossil data and molecular divergence estimates are available. These existing metrics, and other methods that quantify incongruence across topologies including entirely extinct clades, have so far not taken into account uncertainty surrounding both the divergence estimates and the ages of fossils. They have also treated molecular divergence estimates younger than previously assessed fossil minimum estimates of clade age as if they were the same as cases in which they were older. However, these cases are not the same. Recovered divergence dates younger than compared oldest known occurrences require prior hypotheses regarding the phylogenetic position of the compared fossil record and standard assumptions about the relative timing of morphological and molecular change to be incorrect. Older molecular dates, by contrast, are consistent with an incomplete fossil record and do not require prior assessments of the fossil record to be unreliable in some way. Here, we compare previous approaches and introduce two new descriptive metrics. Both metrics explicitly incorporate information on uncertainty by utilizing the 95% confidence intervals on estimated divergence dates and data on stratigraphic uncertainty concerning the age of the compared fossils. Metric scores are maximized when these ranges are overlapping. MDI (minimum divergence incongruence) discriminates between situations where molecular estimates are younger or older than known fossils reporting both absolute fit values and a number score for incompatible nodes. DIG range (divergence implied gap range) allows quantification of the minimum increase in implied missing fossil record induced by enforcing a given set of molecular-based estimates. These metrics are used

  15. Foraminiferal faunal estimates of paleotemperature: Circumventing the no-analog problem yields cool ice age tropics

    USGS Publications Warehouse

    Mix, A.C.; Morey, A.E.; Pisias, N.G.; Hostetler, S.W.

    1999-01-01

    The sensitivity of the tropics to climate change, particularly the amplitude of glacial-to-interglacial changes in sea surface temperature (SST), is one of the great controversies in paleoclimatology. Here we reassess faunal estimates of ice age SSTs, focusing on the problem of no-analog planktonic foraminiferal assemblages in the equatorial oceans that confounds both classical transfer function and modern analog methods. A new calibration strategy developed here, which uses past variability of species to define robust faunal assemblages, solves the no-analog problem and reveals ice age cooling of 5??to 6??C in the equatorial current systems of the Atlantic and eastern Pacific Oceans. Classical transfer functions underestimated temperature changes in some areas of the tropical oceans because core-top assemblages misrepresented the ice age faunal assemblages. Our finding is consistent with some geochemical estimates and model predictions of greater ice age cooling in the tropics than was inferred by Climate: Long-Range Investigation, Mapping, and Prediction (CLIMAP) [1981] and thus may help to resolve a long-standing controversy. Our new foraminiferal transfer function suggests that such cooling was limited to the equatorial current systems, however, and supports CLIMAP's inference of stability of the subtropical gyre centers.

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

    PubMed

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

    2012-06-10

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

  17. Third molar development: evaluation of nine tooth development registration techniques for age estimations.

    PubMed

    Thevissen, Patrick W; Fieuws, Steffen; Willems, Guy

    2013-03-01

    Multiple third molar development registration techniques exist. Therefore the aim of this study was to detect which third molar development registration technique was most promising to use as a tool for subadult age estimation. On a collection of 1199 panoramic radiographs the development of all present third molars was registered following nine different registration techniques [Gleiser, Hunt (GH); Haavikko (HV); Demirjian (DM); Raungpaka (RA); Gustafson, Koch (GK); Harris, Nortje (HN); Kullman (KU); Moorrees (MO); Cameriere (CA)]. Regression models with age as response and the third molar registration as predictor were developed for each registration technique separately. The MO technique disclosed highest R(2) (F 51%, M 45%) and lowest root mean squared error (F 3.42 years; M 3.67 years) values, but differences with other techniques were small in magnitude. The amount of stages utilized in the explored staging techniques slightly influenced the age predictions.

  18. Equations to estimate fetal age at the moment of death in the Mexican population.

    PubMed

    Chávez-Martínez, Perla; Ortega-Palma, Albertina; Castrejón-Caballero, José Luis; Arteaga-Martínez, Manuel

    2016-09-01

    Metric standards are presented for the estimation of fetal age at the time of death in the Mexican population. To obtain these standards, both metric and radiological studies were conducted on 97 fetuses and complete stillborn infants of both sexes, phenotypically normal between 10 and 38 weeks of morphological age. All the fetuses used were the product of spontaneous abortions in Mexico City between 1990 and 2000. Equations were obtained by calibrating quadratic linear regression models adjusted for the diaphyseal length of the humerus, radius, ulna, femur, tibia and fibula, characterized as the most adequate indicators to represent the growth of long bones in this age group, and verified by the evaluation of the model assumptions and the coefficient of determination (R(2)). To conclude, these models facilitate a more precise prediction in fetuses of the Mexican population, constituting the first metric standards of their type at a national level.

  19. Global estimate of the incidence of clinical pneumonia among children under five years of age.

    PubMed Central

    Rudan, Igor; Tomaskovic, Lana; Boschi-Pinto, Cynthia; Campbell, Harry

    2004-01-01

    OBJECTIVE: Clinical pneumonia (defined as respiratory infections associated with clinical signs of pneumonia, principally pneumonia and bronchiolitis) in children under five years of age is still the leading cause of childhood mortality in the world. In this paper we aim to estimate the worldwide incidence of clinical pneumonia in young children. METHODS: Our estimate for the developing world is based on an analysis of published data on the incidence of clinical pneumonia from community based longitudinal studies. Among more than 2000 studies published since 1961, we identified 46 studies that reported the incidence of clinical pneumonia, and 28 of these met pre-defined quality criteria. FINDINGS: The estimate of the median incidence from those studies was 0.28 episodes per child-year (e/cy). The 25-75% interquartile range was 0.21-0.71. We assessed the plausibility of this estimate using estimates of global mortality from acute respiratory infections and reported case fatality rates for all episodes of clinical pneumonia reported in community-based studies or the case-fatality rate reported only for severe cases and estimates of the proportion of severe cases occurring in a defined population or community. CONCLUSION: The overlap between the ranges of the estimates implies that a plausible incidence estimate of clinical pneumonia for developing countries is 0.29 e/cy. This equates to an annual incidence of 150.7 million new cases, 11-20 million (7-13%) of which are severe enough to require hospital admission. In the developed world no comparable data are available. However, large population-based studies report that the incidence of community-acquired pneumonia among children less than five years old is approximately 0.026 e/cy, suggesting that more than 95% of all episodes of clinical pneumonia in young children worldwide occur in developing countries. PMID:15654403

  20. Skeletal age estimation based on medial clavicle--a test of the method reliability.

    PubMed

    Milenkovic, Petar; Djukic, Ksenija; Djonic, Danijela; Milovanovic, Petar; Djuric, Marija

    2013-05-01

    In order to establish a reliable age indicator in the period when all other epiphyseal age indicators have already been inactivated, medial clavicle as the bone with the longest period of growth became the object of various investigations. However, the lack of population-specific method often made it unreliable in some regions. The current study involved a Balkan population and it was designed in order to examine whether morphological, radiological, and histological analyses of medial clavicles could be applied with success in age assessment of individuals beyond their twenties in anthropological and forensic practice. The medial clavicular specimens were collected from contemporary Serbian population, autopsied in the period from 1998 to 2001, encompassing 67 individuals (42 males and 25 females) with the age range from 20 to 90 years. The conducted analyses of morphological features identified the epiphyseal union timing, signs of lipping in the region of the notch for the first rib as well as exostoses and bone overgrowths of the articular surface margin as age-dependent attributes. Trabecular bone volume fraction and minimum trabecular width were also highlighted as age-distinctive microscopic features. Sex difference was ascertainable in epiphyseal union timing, morphology of the notch for the first rib, margin of the articular surface, and basic morphology of articular surface as well as in two microscopic characteristics: trabecular bone volume fraction and minimum trabecular width. The study managed to identify several age- and sex-related features that could be applied as additional guidance for age estimation in Serbian population. PMID:23329360

  1. Effect of Donor Age on the Proportion of Mesenchymal Stem Cells Derived from Anterior Cruciate Ligaments

    PubMed Central

    Lee, Dae-Hee; Ng, Joanne; Kim, Sang-Beom; Sonn, Chung Hee; Lee, Kyung-Mi; Han, Seung-Beom

    2015-01-01

    The characteristics of anterior cruciate ligament (ACL)-derived mesenchymal stem cells (MSCs), such as proportion and multilineage potential, can be affected by donor age. However, the qualitative and quantitative features of ACL MSCs isolated from younger and older individuals have not yet been compared directly. This study assessed the phenotypic and functional differences in ACL-MSCs isolated from younger and older donors and evaluated the correlation between ACL-MSC proportion and donor age. Torn ACL remnants were harvested from 36 patients undergoing ACL reconstruction (young: 29.67 ± 10.92 years) and 33 undergoing TKA (old: 67.96 ± 5.22 years) and the proportion of their MSCs were measured. The mean proportion of MSCs was slightly higher in older ACL samples of the TKA group than of the younger ACL reconstruction group (19.69 ± 8.57% vs. 15.33 ± 7.49%, p = 0.024), but the proportions of MSCs at passages 1 and 2 were similar. MSCs from both groups possessed comparable multilineage potentiality, as they could be differentiated into adipocytes, osteocytes, and chondrocytes at similar level. No significant correlations were observed between patient age and MSC proportions at passages 0–2 or between age and MSC proportion in both the ACL reconstruction and TKA groups. Multiple linear regression analysis found no significant predictor of MSC proportion including donor age for each passage. Microarray analysis identified several genes that were differentially regulated in ACL-MSCs from old TKA patients compared to young ACL reconstruction patients. Genes of interest encode components of the extracellular matrix (ECM) and may thus play a crucial role in modulating tissue homeostasis, remodeling, and repair in response to damage or disease. In conclusion, the proportion of freshly isolated ACL-MSC was higher in elderly TKA patients than in younger patients with ACL tears, but their phenotypic and multilineage potential were comparable. PMID:25729860

  2. A case of an adoptive girl with precocious puberty: the problem of age estimation.

    PubMed

    De Donno, Antonio; Roca, Roberta; Introna, Francesco; Santoro, Valeria

    2013-09-10

    Age estimation is one of the main tasks of forensic anthropology and odontology, both on the dead and the living. In living subjects, age estimation may be used to establish an individual's status as a minor in cases involving adoption, criminal responsibility, child pornography, and those seeking asylum, especially where adequate identification documents are lacking. The authors report a case about age assessment of a girl born in Mbujimayi (Democratic Republic of Congo) and later adopted in Italy. The birth certificate issued after finding the child in a state of abandonment (in December 2007), bore date of 12.12.2004, but this was in contrast with the year of birth - 2003 - stated on the certification available to the center that had provided accommodation to the girl in Africa. Her adoptive parents reported that the child had been diagnosed with precocious puberty and was thus under treatment. She weighed 32.5 kg and was 132.5 cm tall. Body mass index (BMI) corresponded to the range between 9.5 and 14 years of age. The assessment of maturity indicators (sexual characteristics) placed the child at the lower limits of Stage II of Tanner's classification (sparse growth of long, slightly darkened, downy straight pubic hair; elevation of the breast and nipple as a small mound with increased diameter of the areolae). The skeletal age was determined by taking X-rays of the hand and wrist using Fels, TW2 and Greulich and Pyle methods. Dental growth was assessed through orthopantomogram using Demirjian's technique. The methods applied were adjusted considering the studies on African population found in the literature, and a skeletal and dental age of 10 years was established. Afterwards, the wrist X-rays performed at the Children's Hospital of Bari, 7 months before our investigation, revealed a skeletal age of 7 years. This evidence showed that, despite the treatment the child had promptly initiated, early puberty had influenced the skeletal growth with an acceleration

  3. Age estimation of immature human skeletal remains from the diaphyseal length of the long bones in the postnatal period.

    PubMed

    Cardoso, Hugo F V; Abrantes, Joana; Humphrey, Louise T

    2014-09-01

    Age at death in immature human skeletal remains has been estimated from the diaphyseal length of the long bones, but few studies have actually been designed specifically for the purpose of age estimation and those which have, show important caveats. This study uses regression and classical calibration to model the relationship between age and diaphyseal length of the six long bones, in a sample of 184 known sex and age individuals (72 females and 112 males), younger than 13 years of age, selected from Portuguese and English skeletal collections. Age estimation models based on classical calibration were obtained for each of the six long bones, and separately for each sex and for the sexes combined, and also for the entire sample and when it is subdivided into two subsamples at the age of 2 years. Comparisons between inverse and classical calibration show there is a systematic bias in age estimations obtained from inverse calibration. In the classical calibration models, the length of the femur provides the most accurate estimates of age. Age estimates are more accurate for the male subsample and for individuals under the age of 2 years. These results and a test of previously published methods caution against inverse calibration as a technique for developing age estimation methods even from the immature skeleton. Age estimation methods developed using cemetery collections of identified human skeletons should not be uncritically applied to present-day populations from the same region since many populations have experienced dramatic secular trends in growth and adult height over the last century.

  4. Exploiting the structure of MWR-derived temperature profile for stable boundary-layer height estimation

    NASA Astrophysics Data System (ADS)

    Saeed, Umar; Rocadenbosch, Francesc

    2015-10-01

    A method for the estimation of Stable Boundary Layer Height (SBLH) using curvature of the potential temperature profiles retrieved by a Microwave Radiometer (MWR) is presented. The vertical resolution of the MWR-derived temperature profile decreases with the height. A spline interpolation is carried-out to obtain a uniformly discretized temperature profile. The curvature parameter is calculated from the first and second order derivatives of the interpolated potential temperature profile. The first minima of the curvature parameter signifies the point where the temperature profile starts changing from the stable to the residual conditions. The performance of the method is analyzed by comparing it against physically idealized models of the stable boundary-layer temperature profile available in the literature. There are five models which include stable-mixed, mixed-linear, linear, polynomial and exponential. For a given temperature profile these five models are fitted using the non-linear least-squares approach. The best fitting model is chosen as the one which fits with the minimum root-mean-square error. Comparison of the SBLH estimates from curvature-based method with the physically idealized models shows that the method works qualitatively and quantitatively well with lower variation. Potential application of this approach is the situation where given temperature profiles are significantly deviant from the idealized models. The method is applied to data from a Humidity-and-Temperature Profiler (HATPRO) MWR collected during the HD(CP)2 Observational Prototype Experiment (HOPE) campaign at Jülich, Germany. Radiosonde data, whenever available, is used as the ground-truth.

  5. Deriving Theoretical Boundaries to Address Domain and Resolution Dependencies of Triangle Models for Evapotranspiration Estimation

    NASA Astrophysics Data System (ADS)

    Long, D.; Singh, V. P.; Scanlon, B. R.

    2011-12-01

    Satellite-based triangle models for evapotranspiration (ET) are unique in interpreting the contextual relationship between Normalized Difference Vegetation Index (NDVI)/factional vegetation cover (fc) and surface radiative temperature (Trad) to deduce evaporative fraction (EF) and ET across large heterogeneous areas. The outputs and performance of some satellite-based ET algorithms may be dependent on the domain of a study site being considered and the resolution of satellite imagery being used. These attributes are referred to as domain dependence and resolution dependence. To unravel the domain and resolution dependencies of the triangle models and test the utility of the triangle models using high spatial resolution images, the triangle models were applied to areas with progressively growing domains and to Landsat TM/ETM+ and MODIS sensors, respectively, at the Soil Moisture-Atmosphere Coupling Experiment (SMACEX) site in central Iowa, U.S. on Day of Year (DOY) 174 and 182 in year 2002. Results indicate that the triangle models can be domain-dependent and resolution-dependent, showing large uncertainties in the evaporative fraction estimates in terms of a Mean Absolute Percentage Difference (MAPD) up to ~50%. We derived the theoretical boundaries of the fc-Trad space to restrain the domain and resolution dependencies of the triangle models. The theoretical warm edge was derived by solving for temperatures of the driest bare surface and the fully vegetated surface with the largest water stress implicit in both radiation budget and energy balance equations. The areal average temperature can be taken as the theoretical cold edge. The triangle models appear to perform well across large areas but fail to predict the evaporative fraction over small areas. However, performance of the triangle models across small domains can be improved by incorporating the theoretical boundaries. Combining the triangle models with the theoretical boundaries can effectively reduce

  6. Age Starting Sigmoidoscopy or Colonoscopy Exams Maps and Data of Model-Based Small Area Estimates - Small Area Estimates

    Cancer.gov

    Age Starting Sigmoidoscopy or Colonoscopy Exams is defined as a person 18 years of age or older who must have reported that he/she thinks that at age 50 people supposed to start having sigmoidoscopy or colonoscopy exams.

  7. The influence of soy-derived phosphatidylserine on cognition in age-associated memory impairment.

    PubMed

    Jorissen, B L; Brouns, F; Van Boxtel, M P; Ponds, R W; Verhey, F R; Jolles, J; Riedel, W J

    2001-01-01

    Phosphatidylserine (PS) is a phospholipid widely sold as a nutritional supplement. PS has been claimed to enhance neuronal membrane function and hence cognitive function, especially in the elderly. We report the results of a clinical trial of soybean-derived PS (S-PS) in aging subjects with memory complaints. Subjects were 120 elderly (> 57 years) of both sexes who fulfilled the more stringent criteria for age-associated memory impairment (AAMI); some also fulfilled the criteria for age-associated cognitive decline. Subjects were allocated at random to one of the three treatment groups: placebo, 300mg S-PS daily, or 600mg S-PS daily. Assessments were carried out at baseline, after 6 and 12 weeks of treatment, and after a wash-out period of 3 weeks. Tests of learning and memory, choice reaction time, planning and attentional functions were administered at each assessment. Delayed recall and recognition of a previously learned word list comprised the primary outcome measures. No significant differences were found in any of the outcome variables between the treatment groups. There were also no significant interactions between treatment and 'severity of memory complaints'. In conclusion, a daily supplement of S-PS does not affect memory or other cognitive functions in older individuals with memory complaints. PMID:11842880

  8. Age-associated metabolic dysregulation in bone marrow-derived macrophages stimulated with lipopolysaccharide

    NASA Astrophysics Data System (ADS)

    Fei, Fan; Lee, Keith M.; McCarry, Brian E.; Bowdish, Dawn M. E.

    2016-03-01

    Macrophages are major contributors to age-associated inflammation. Metabolic processes such as oxidative phosphorylation, glycolysis and the urea cycle regulate inflammatory responses by macrophages. Metabolic profiles changes with age; therefore, we hypothesized that dysregulation of metabolic processes could contribute to macrophage hyporesponsiveness to LPS. We examined the intracellular metabolome of bone marrow-derived macrophages from young (6-8 wk) and old (18-22 mo) mice following lipopolysaccharide (LPS) stimulation and tolerance. We discovered known and novel metabolites that were associated with the LPS response of macrophages from young mice, which were not inducible in macrophages from old mice. Macrophages from old mice were largely non-responsive towards LPS stimulation, and we did not observe a shift from oxidative phosphorylation to glycolysis. The critical regulatory metabolites succinate, γ-aminobutyric acid, arginine, ornithine and adenosine were increased in LPS-stimulated macrophages from young mice, but not macrophages from old mice. A shift between glycolysis and oxidative phosphorylation was not observed during LPS tolerance in macrophages from either young or old mice. Metabolic bottlenecks may be one of the mechanisms that contribute to the dysregulation of LPS responses with age.

  9. Age-associated metabolic dysregulation in bone marrow-derived macrophages stimulated with lipopolysaccharide

    PubMed Central

    Fei, Fan; Lee, Keith M.; McCarry, Brian E.; Bowdish, Dawn M. E.

    2016-01-01

    Macrophages are major contributors to age-associated inflammation. Metabolic processes such as oxidative phosphorylation, glycolysis and the urea cycle regulate inflammatory responses by macrophages. Metabolic profiles changes with age; therefore, we hypothesized that dysregulation of metabolic processes could contribute to macrophage hyporesponsiveness to LPS. We examined the intracellular metabolome of bone marrow-derived macrophages from young (6–8 wk) and old (18–22 mo) mice following lipopolysaccharide (LPS) stimulation and tolerance. We discovered known and novel metabolites that were associated with the LPS response of macrophages from young mice, which were not inducible in macrophages from old mice. Macrophages from old mice were largely non-responsive towards LPS stimulation, and we did not observe a shift from oxidative phosphorylation to glycolysis. The critical regulatory metabolites succinate, γ-aminobutyric acid, arginine, ornithine and adenosine were increased in LPS-stimulated macrophages from young mice, but not macrophages from old mice. A shift between glycolysis and oxidative phosphorylation was not observed during LPS tolerance in macrophages from either young or old mice. Metabolic bottlenecks may be one of the mechanisms that contribute to the dysregulation of LPS responses with age. PMID:26940652

  10. Age-dependent relevance of endogenous 5-lipoxygenase derivatives in anxiety-like behavior in mice.

    PubMed

    Leo, Luciana M; Almeida-Corrêa, Suellen; Canetti, Claudio A; Amaral, Olavo B; Bozza, Fernando A; Pamplona, Fabricio A

    2014-01-01

    When 5-lipoxygenase (5-LO) is inhibited, roughly half of the CNS effect of the prototypic endocannabinoid anandamide (AEA) is lost. Therefore, we decided to investigate whether inhibiting this enzyme would influence physiological functions classically described as being under control of the endocannabinoid system. Although 5-LO inhibition by MK-886 reduced lipoxin A4 levels in the brain, no effect was found in the elevated plus maze (EPM), even at the highest possible doses, via i.p. (10 mg/kg,) or i.c.v. (500 pmol/2 µl) routes. Accordingly, no alterations in anxiety-like behavior in the EPM test were observed in 5-LO KO mice. Interestingly, aged mice, which show reduced circulating lipoxin A4 levels, were sensitive to MK-886, displaying an anxiogenic-like state in response to treatment. Moreover, exogenous lipoxin A4 induced an anxiolytic-like profile in the EPM test. Our findings are in line with other reports showing no difference between FLAP KO or 5-LO KO and their control strains in adult mice, but increased anxiety-like behavior in aged mice. We also show for the first time that lipoxin A4 affects mouse behavior. In conclusion, we propose an age-dependent relevancy of endogenous 5-LO derivatives in the modulation of anxiety-like behavior, in addition to a potential for exogenous lipoxin A4 in producing an anxiolytic-like state.

  11. Age-associated metabolic dysregulation in bone marrow-derived macrophages stimulated with lipopolysaccharide

    NASA Astrophysics Data System (ADS)

    Fei, Fan; Lee, Keith M.; McCarry, Brian E.; Bowdish, Dawn M. E.

    2016-03-01

    Macrophages are major contributors to age-associated inflammation. Metabolic processes such as oxidative phosphorylation, glycolysis and the urea cycle regulate inflammatory responses by macrophages. Metabolic profiles changes with age; therefore, we hypothesized that dysregulation of metabolic processes could contribute to macrophage hyporesponsiveness to LPS. We examined the intracellular metabolome of bone marrow-derived macrophages from young (6–8 wk) and old (18–22 mo) mice following lipopolysaccharide (LPS) stimulation and tolerance. We discovered known and novel metabolites that were associated with the LPS response of macrophages from young mice, which were not inducible in macrophages from old mice. Macrophages from old mice were largely non-responsive towards LPS stimulation, and we did not observe a shift from oxidative phosphorylation to glycolysis. The critical regulatory metabolites succinate, γ-aminobutyric acid, arginine, ornithine and adenosine were increased in LPS-stimulated macrophages from young mice, but not macrophages from old mice. A shift between glycolysis and oxidative phosphorylation was not observed during LPS tolerance in macrophages from either young or old mice. Metabolic bottlenecks may be one of the mechanisms that contribute to the dysregulation of LPS responses with age.

  12. Satellite-derived estimations of spatial and seasonal variation in tropospheric carbon dioxide mass over China

    PubMed Central

    Xu, Yuyue; Ke, Changqing; Wang, Juanle; Sun, Jiulin; Liu, Yang; Harris, Warwick; Kou, Cheng

    2013-01-01

    China has frequently been questioned about the data transparency and accuracy of its energy and emission statistics. Satellite-derived remote sensing data potentially provide a useful tool to study the variation in carbon dioxide (CO2) mass over areas of the earth's surface. In this study, Greenhouse gases Observing SATellite (GOSAT) tropospheric CO2 concentration data and NCEP/NCAR reanalysis tropopause data were integrated to obtain estimates of tropospheric CO2 mass variations over the surface of China. These variations were mapped to show seasonal and spatial patterns with reference to China's provincial areas. The estimates of provincial tropospheric CO2 were related to statistical estimates of CO2 emissions for the provinces and considered with reference to provincial populations and gross regional products (GRP). Tropospheric CO2 masses for the Chinese provinces ranged from 53 ± 1 to 14,470 ± 63 million tonnes were greater for western than for eastern provinces and were primarily a function of provincial land area. Adjusted for land area troposphere CO2 mass was higher for eastern and southern provinces than for western and northern provinces. Tropospheric CO2 mass over China varied with season being highest in July and August and lowest in January and February. The average annual emission from provincial energy statistics of CO2 by China was estimated as 10.3% of the average mass of CO2 in the troposphere over China. The relationship between statistical emissions relative to tropospheric CO2 mass was higher than 20% for developed coastal provinces of China, with Shanghai, Tianjin, and Beijing having exceptionally high percentages. The percentages were generally lower than 10% for western inland provinces. Provincial estimates of emissions of CO2 were significantly positively related to provincial populations and gross regional products (GRP) when the values for the provincial municipalities Shanghai, Tianjin, and Beijing were excluded from the linear

  13. Age estimation by dental developmental stages in children and adolescents in Iceland.

    PubMed

    Vidisdottir, Sigridur Rosa; Richter, Svend

    2015-12-01

    Studies have shown that it is necessary to create a database for dental maturity for every population and compare it to others. The present study is the first one for dental development in the Icelandic population the age range being 4-24 years. It will help in forensic dental age estimation and will also help dentists, physicians, anthropologists, archaeologists and other professionals who rely on developmental age assessment in children and adolescents. In this present retrospective cross-sectional study, dental maturity was determined in 1100 Icelandic children and adolescents from orthopantomograms (OPGs). The first 100 were used for a pilot study and the remaining 1000 for the main study. A total of 23 subjects were excluded. The sample consisted of 508 girls and 469 boys from the age of 4-24 years and a dental developmental scoring system was used as a standard for determination of dental maturity stages. A total of 200 OPGs were studied both on the left and right side and the remaining on the right side. Dental maturity was established for all teeth and both genders, when the sample permitted, from the beginning of crown formation to the root apex closure. The Cronbach's Alpha reliability test showed high reliability, R=0.982. Girls in Iceland reach dental maturity root completed (stage 10, Rc) at 17.81 years of age for the maxillary and at 18.47 years for the mandibular teeth. Boys reach dental maturity root completed (stage 10, Rc) at 18.00 years of age in the maxilla and 17.63 in the mandible. There was no significant difference between left and right side (r=0.95-1.00) and there was no gender difference, except in root formation in maxillary and mandibular canines where girls reached root completed earlier than boys. A reliable database has been established in Iceland for tooth development in the age range of 4-24 years, which is compatible with international studies. These results will help forensic odontologists and other professionals to estimate with

  14. Estimates of atmospheric deposition of submicron particle-associated combustion derived organic contaminants to Chesapeake Bay

    SciTech Connect

    Leister, D.L. |; Baker, J.E.

    1994-12-31

    Once emitted into the atmosphere, combustion derived organic contaminants partition between gaseous and particle phases. In order to estimate the wet and dry removal of contaminants from the atmospheric to surface waters, it is necessary to measure gaseous and particle-associated contaminant concentrations because the deposition mechanisms of each phase differ. The authors estimate dry and wet depositional fluxes of polycyclic aromatic hydrocarbons (PAH) as a function of large and small particles to provide insight to the contribution of small particles to the overall atmospheric flux of organic contaminants to surface waters. Utilizing data gathered from concurrent measurements of 10 PAHs associated with particles in rain an in the atmosphere adjacent to Chesapeake Bay, and from PAH particle-size distribution data recently collected at Egbert, Ontario, calculated non-crustal PAH dry particle fluxes range from 40 to as high as 160 ng/m{sup 2}/month. Despite the lower estimated deposition velocity for noncrustal particles relative to that for partially crustal particles, non-crustal PAH particle fluxes are about a factor of five larger than those calculated for particles with a partial crustal component. Monthly wet fluxes of submicron particles range from 12 to 260 ng/m{sup 2}/month and in contrast to dry periods, are similar to those for large particles. Their calculations suggest that the atmospheric loading of submicron particle associated PAHs on an annual basis during dry and wet periods are significant due to the high concentrations of contaminants in this size range in both air and rain.

  15. Steady state estimation of soil organic carbon using satellite-derived canopy leaf area index

    NASA Astrophysics Data System (ADS)

    Fang, Yilin; Liu, Chongxuan; Huang, Maoyi; Li, Hongyi; Leung, L. Ruby

    2014-12-01

    Estimation of soil organic carbon (SOC) stock using models typically requires long term spin-up of the carbon-nitrogen (CN) models, which has become a bottleneck for global modeling. We report a new numerical approach to estimate global SOC stock that can alleviate long spin-up. The approach uses satellite-based canopy leaf area index (LAI) and takes advantage of a reaction-based biogeochemical module—Next Generation BioGeoChemical Module (NGBGC) that was recently developed and incorporated in version 4 of the Community Land Model (CLM4). Although NGBGC uses the same CN mechanisms as in CLM4CN, it can be easily configured to run prognostic or steady state simulations. The new approach was applied at point and global scales and compared with SOC derived from spin-up by running NGBGC in the prognostic mode, and SOC from the Harmonized World Soil Database (HWSD). The steady state solution is comparable to the spin-up value when the satellite LAI is close to that from the spin-up solution, and largely captured the global variability of the HWSD SOC across the different dominant plant functional types (PFTs). The correlation between the simulated and HWSD SOC was, however, weak at both point and global scales, suggesting the needs for improving the biogeochemical processes described in CLM4 and updating HWSD. Besides SOC, the steady state solution also includes all other state variables simulated by a spin-up run, which makes the tested approach a promising tool to efficiently estimate global SOC distribution and evaluate and compare multiple aspects simulated by different CN mechanisms in the model.

  16. Agricultural Decision Support Through Robust Assimilation of Satellite Derived Soil Moisture Estimates

    NASA Astrophysics Data System (ADS)

    Mishra, V.; Cruise, J.; Mecikalski, J. R.

    2012-12-01

    Soil Moisture is a key component in the hydrological process, affects surface and boundary layer energy fluxes and is the driving factor in agricultural production. Multiple in situ soil moisture measuring instruments such as Time-domain Reflectrometry (TDR), Nuclear Probes etc. are in use along with remote sensing methods like Active and Passive Microwave (PM) sensors. In situ measurements, despite being more accurate, can only be obtained at discrete points over small spatial scales. Remote sensing estimates, on the other hand, can be obtained over larger spatial domains with varying spatial and temporal resolutions. Soil moisture profiles derived from satellite based thermal infrared (TIR) imagery can overcome many of the problems associated with laborious in-situ observations over large spatial domains. An area where soil moisture observation and assimilation is receiving increasing attention is agricultural crop modeling. This study revolves around the use of the Decision Support System for Agrotechnology Transfer (DSSAT) crop model to simulate corn yields under various forcing scenarios. First, the model was run and calibrated using observed precipitation and model generated soil moisture dynamics. Next, the modeled soil moisture was updated using estimates derived from satellite based TIR imagery and the Atmospheric Land Exchange Inverse (ALEXI) model. We selected three climatically different locations to test the concept. Test Locations were selected to represent varied climatology. Bell Mina, Alabama - South Eastern United States, representing humid subtropical climate. Nabb, Indiana - Mid Western United States, representing humid continental climate. Lubbok, Texas - Southern United States, representing semiarid steppe climate. A temporal (2000-2009) correlation analysis of the soil moisture values from both DSSAT and ALEXI were performed and validated against the Land Information System (LIS) soil moisture dataset. The results clearly show strong

  17. RESEARCH PAPER: Old stellar population synthesis: new age and mass estimates for Mayall II = G1

    NASA Astrophysics Data System (ADS)

    Ma, Jun; de Grijs, Richard; Fan, Zhou; Rey, Soo-Chang; Wu, Zhen-Yu; Zhou, Xu; Wu, Jiang-Hua; Jiang, Zhao-Ji; Chen, Jian-Sheng; Lee, Kyungsook; Sohn, Sangmo Tony

    2009-06-01

    Mayall II = G1 is one of the most luminous globular clusters (GCs) in M31. Here, we determine its age and mass by comparing multicolor photometry with theoretical stellar population synthesis models. Based on far- and near-ultraviolet GALEX photometry, broad-band UBVRI, and infrared JHKS 2MASS data, we construct the most extensive spectral energy distribution of G1 to date, spanning the wavelength range from 1538 to 20 000 Å. A quantitative comparison with a variety of simple stellar population (SSP) models yields a mean age which is consistent with G1 being among the oldest building blocks of M31 and having formed within ~1.7 Gyr after the Big Bang. Irrespective of the SSP model or stellar initial mass function adopted, the resulting mass estimates (of order 107 Modot) indicate that G1 is one of the most massive GCs in the Local Group. However, we speculate that the cluster's exceptionally high mass suggests that it may not be a genuine GC. Our results also suggest that G1 may contain, on average, (1.65±0.63) × 102 Lodot far-ultraviolet-bright, hot, extreme horizontal-branch stars, depending on the adopted SSP model. In addition, we demonstrate that extensive multi-passband photometry coupled with SSP analysis enables one to obtain age estimates for old SSPs that have similar accuracies as those from integrated spectroscopy or resolved stellar photometry, provided that some of the free parameters can be constrained independently.

  18. Dental age estimation in a Brazilian adult population using Cameriere's method.

    PubMed

    Azevedo, Alana de Cássia Silva; Alves, Nathalia Zanini; Michel-Crosato, Edgard; Rocha, Marcos; Cameriere, Roberto; Biazevic, Maria Gabriela Haye

    2015-01-01

    The objectives of this study were to develop a specific formula to estimate age in a Brazilian adult population and to compare the original formula from Cameriere to this Brazilian formula. The sample comprised 1,772 periapical radiographs from 443 subjects (219 men, 224 women) that were organized into 12 groups according to sex (men or women) and age (20-29, 30-39, 40-49, 50-59, 60-69, and 70 years and older). The films were analyzed using the criteria described by Cameriere et al. (2004) and Adobe Photoshop®. We obtained a mean error of 8.56 (SD = 5.80) years for tooth 13, 7.99 (SD = 5.78) years for tooth 23, 8.38 (SD = 6.26) years for tooth 33, and 8.20 (SD = 6.54) years for tooth 43. When teeth were combined in the analysis, we observed lower mean errors. The Brazilian formula developed from this sample group was more accurate than Cameriere's formula. However, other factors must be considered to improve age estimates in adults. PMID:25590504

  19. Dental age estimation in a Brazilian adult population using Cameriere's method.

    PubMed

    Azevedo, Alana de Cássia Silva; Alves, Nathalia Zanini; Michel-Crosato, Edgard; Rocha, Marcos; Cameriere, Roberto; Biazevic, Maria Gabriela Haye

    2015-01-01

    The objectives of this study were to develop a specific formula to estimate age in a Brazilian adult population and to compare the original formula from Cameriere to this Brazilian formula. The sample comprised 1,772 periapical radiographs from 443 subjects (219 men, 224 women) that were organized into 12 groups according to sex (men or women) and age (20-29, 30-39, 40-49, 50-59, 60-69, and 70 years and older). The films were analyzed using the criteria described by Cameriere et al. (2004) and Adobe Photoshop®. We obtained a mean error of 8.56 (SD = 5.80) years for tooth 13, 7.99 (SD = 5.78) years for tooth 23, 8.38 (SD = 6.26) years for tooth 33, and 8.20 (SD = 6.54) years for tooth 43. When teeth were combined in the analysis, we observed lower mean errors. The Brazilian formula developed from this sample group was more accurate than Cameriere's formula. However, other factors must be considered to improve age estimates in adults.

  20. Estimating the age of fire in the Cape flora of South Africa from an orchid phylogeny

    PubMed Central

    Bytebier, Benny; Antonelli, Alexandre; Bellstedt, Dirk U.; Linder, H. Peter

    2011-01-01

    Fire may have been a crucial component in the evolution of the Cape flora of South Africa, a region characterized by outstanding levels of species richness and endemism. However, there is, to date, no critical assessment of the age of the modern fire regime in this biome. Here, we exploit the presence of two obligate post-fire flowering clades in the orchid genus Disa, in conjunction with a robust, well-sampled and dated molecular phylogeny, to estimate the age by which fire must have been present. Our results indicate that summer drought (winter rainfall), the fire regime and the fynbos vegetation are several million years older than currently suggested. Summer drought and the fynbos vegetation are estimated to date back to at least the Early Miocene (ca 19.5 Ma). The current fire regime may have been established during a period of global cooling that followed the mid-Miocene Climatic Optimum (ca 15 Ma), which led to the expansion of open habitats and increased aridification. The first appearance of Disa species in the grassland biome, as well as in the subalpine habitat, is in striking agreement with reliable geological and palaeontological evidence of the age of these ecosystems, thus corroborating the efficacy of our methods. These results change our understanding of the historical mechanisms underlying botanical evolution in southern Africa, and confirm the potential of using molecular phylogenies to date events for which other information is lacking or inconclusive. PMID:20685712

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

    PubMed

    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.

  2. [Estimating the age of start of drug abuse in cross-sectional surveys exemplified by the Swiss Health Survey].

    PubMed

    Gmel, G; Rehm, J

    1996-01-01

    This paper is based on data from the first Swiss Health Survey, but deals with a more general problem; the estimation of age of onset in illegal substance consumption. First, it is shown that taking the arithmetic mean for different age-groups as estimator leads to an underestimation of age of onset in the younger groups. Consequently, an alternative method is proposed based on survival models with right censoring. The prediction of age of onset is modeled with nonlinear functions. Results show for cannabis consumption in Switzerland that age of onset did not decrease notably during the past decade.

  3. Dental age estimation utilizing third molar development: A review of principles, methods, and population studies used in the United States.

    PubMed

    Lewis, James M; Senn, David R

    2010-09-10

    When an individual reaches the age of legal majority, their treatment within the criminal and civil legal systems is changed dramatically in the United States. Forensic odontologists are often asked to assist government agencies in estimating the ages of persons who may or may not have reached that legally important age. The third molars are the only teeth useful as forensic estimators of chronological age in the target age group. This study reviews the principles, methodology, and population data of the most commonly used technique in the United States, the analysis of the third molar development based on modified Demirjian staging. The method analyzes the developing third molar to estimate mean age, age intervals and the empirical probability that an individual has reached the anniversary of her or his eighteenth birthday.

  4. Estimating Modifying Effect of Age on Genetic and Environmental Variance Components in Twin Models.

    PubMed

    He, Liang; Sillanpää, Mikko J; Silventoinen, Karri; Kaprio, Jaakko; Pitkäniemi, Janne

    2016-04-01

    Twin studies have been adopted for decades to disentangle the relative genetic and environmental contributions for a wide range of traits. However, heritability estimation based on the classical twin models does not take into account dynamic behavior of the variance components over age. Varying variance of the genetic component over age can imply the existence of gene-environment (G×E) interactions that general genome-wide association studies (GWAS) fail to capture, which may lead to the inconsistency of heritability estimates between twin design and GWAS. Existing parametricG×Einteraction models for twin studies are limited by assuming a linear or quadratic form of the variance curves with respect to a moderator that can, however, be overly restricted in reality. Here we propose spline-based approaches to explore the variance curves of the genetic and environmental components. We choose the additive genetic, common, and unique environmental variance components (ACE) model as the starting point. We treat the component variances as variance functions with respect to age modeled by B-splines or P-splines. We develop an empirical Bayes method to estimate the variance curves together with their confidence bands and provide an R package for public use. Our simulations demonstrate that the proposed methods accurately capture dynamic behavior of the component variances in terms of mean square errors with a data set of >10,000 twin pairs. Using the proposed methods as an alternative and major extension to the classical twin models, our analyses with a large-scale Finnish twin data set (19,510 MZ twins and 27,312 DZ same-sex twins) discover that the variances of the A, C, and E components for body mass index (BMI) change substantially across life span in different patterns and the heritability of BMI drops to ∼50% after middle age. The results further indicate that the decline of heritability is due to increasing unique environmental variance, which provides more

  5. The Hercules-Lyra association revisited. New age estimation and multiplicity study

    NASA Astrophysics Data System (ADS)

    Eisenbeiss, T.; Ammler-von Eiff, M.; Roell, T.; Mugrauer, M.; Adam, Ch.; Neuhäuser, R.; Schmidt, T. O. B.; Bedalov, A.

    2013-08-01

    Context. The Hercules-Lyra association, a purported nearby young moving group, contains a few tens of zero age main sequence stars of spectral types F to M. The existence and the properties of the Her-Lyr association are controversial and have been discussed in the literature. Aims: The present work reassesses the properties and the member list of the Her-Lyr association based on kinematics and age indicators. Many objects form multiple systems or have low-mass companions and so we need to properly account for multiplicity. Methods: We use our own new imaging observations and archival data to identify multiple systems. The colors and magnitudes of kinematic candidates are compared to isochrones. We derive further information on the age based on Li depletion, rotation, and coronal and chromospheric activity. A set of canonical members is identified to infer mean properties. Membership criteria are derived from the mean properties and used to discard non-members. Results: The candidates selected from the literature belong to 35 stellar systems, 42.9% of which are multiple. Four multiple systems (V538 Aur, DX Leo, V382 Ser, and HH Leo) are confirmed in this work by common proper motion. An orbital solution is presented for the binary system which forms a hierarchical triple with HH Leo. Indeed, a group of candidates displays signatures of youth. Seven canonical members are identified The distribution of Li equivalent widths of canonical Her-Lyr members is spread widely and is similar to that of the Pleiades and the UMa group. Gyrochronology gives an age of 257 ± 46 Myr which is roughly in between the ages of the Pleiades and the Ursa Major group. The measures of chromospheric and coronal activity support the young age. Four membership criteria are presented based on kinematics, lithium equivalent width, chromospheric activity, and gyrochronological age. In total, eleven stars are identified as certain members including co-moving objects plus additional 23 possible

  6. Age estimation using annulations in root cementum of human teeth: A comparison between longitudinal and cross sections

    PubMed Central

    Mallar, Kavya B; Girish, HC; Murgod, Sanjay; Kumar, BN Yathindra

    2015-01-01

    Background: Age estimation is an important factor in the identification of an individual in forensic science. Research indicates that cemental annulations may be used more reliably than other morphological or histological traits of human skeleton for age estimation. Materials and Methods: Twenty-five teeth were sectioned longitudinally, and twenty-five teeth were cross-sectioned at the mid portion of the root. Sections were ground, mounted and viewed under a bright light microscope. The area selected for counting was photographed under ×10 objective, magnified 5 times; cemental lines were counted and added to the eruption age of that patient, to obtain the chronological age. The statistical software SAS 9.2, SPSS 15.0, Stata 10.1, MedCalc 9.0.1, Systat 12.0 and R environment ver.2.11.1 were used for the analysis of the data. Results: The P value comparing actual age and calculated age using longitudinal sections is moderately significant and the P value comparing actual age and calculated age in the age group of <30 years is significant. Interpretation and Conclusion: The middle third of tooth root was most suitable to count annulations. The cross sections are easier to count but longitudinal sections give more appropriate results on age estimation. Though the procedure predicts under assessment of age in the younger age group and over assessment of age in the older age group, it provides a close estimate of the actual age of an individual. It can be correlated with other age estimation methods for better reliability. PMID:26980973

  7. Estimating age-based antiretroviral therapy costs for HIV-infected children in resource-limited settings based on World Health Organization weight-based dosing recommendations

    PubMed Central

    2014-01-01

    Background Pediatric antiretroviral therapy (ART) has been shown to substantially reduce morbidity and mortality in HIV-infected infants and children. To accurately project program costs, analysts need accurate estimations of antiretroviral drug (ARV) costs for children. However, the costing of pediatric antiretroviral therapy is complicated by weight-based dosing recommendations which change as children grow. Methods We developed a step-by-step methodology for estimating the cost of pediatric ARV regimens for children ages 0–13 years old. The costing approach incorporates weight-based dosing recommendations to provide estimated ARV doses throughout childhood development. Published unit drug costs are then used to calculate average monthly drug costs. We compared our derived monthly ARV costs to published estimates to assess the accuracy of our methodology. Results The estimates of monthly ARV costs are provided for six commonly used first-line pediatric ARV regimens, considering three possible care scenarios. The costs derived in our analysis for children were fairly comparable to or slightly higher than available published ARV drug or regimen estimates. Conclusions The methodology described here can be used to provide an accurate estimation of pediatric ARV regimen costs for cost-effectiveness analysts to project the optimum packages of care for HIV-infected children, as well as for program administrators and budget analysts who wish to assess the feasibility of increasing pediatric ART availability in constrained budget environments. PMID:24885453

  8. Estimating the age of stone structures using OSL: the potential of entrapped sediment

    NASA Astrophysics Data System (ADS)

    Baran, J.; Murray, A. S.; Häggström, L.

    2003-05-01

    We report on the potential of using optically stimulated luminescence (OSL) to determine the construction age of various stone structures at an archaeological site at Öggestorp, near Jönköping in southern Sweden. The sediment filling the interstices between stones in a wall and a clearance cairn is assumed to have been light exposed during or before construction, and we anticipated that these fill samples were likely to be incompletely bleached, so that the smallest doses would be the most relevant. However, any reworking of the structures, or even later aeolian events, could emplace a small fraction of younger materials, and so there were also likely to be some grains with substantially smaller doses. The dose distributions from such fill samples have been studied using both small aliquots and individual grains of quartz. We present preliminary construction ages for a stone wall and cairn based on these dose distributions, and compare these with independent age constraints derived from OSL ages of associated heated stones and aeolian sand, and from the other archaeological evidence.

  9. ASSET (Age/Sex Standardised Estimates of Treatment): A Research Model to Improve the Governance of Prescribing Funds in Italy

    PubMed Central

    Favato, Giampiero; Mariani, Paolo; Mills, Roger W.; Capone, Alessandro; Pelagatti, Matteo; Pieri, Vasco; Marcobelli, Alberico; Trotta, Maria G.; Zucchi, Alberto; Catapano, Alberico L.

    2007-01-01

    Background The primary objective of this study was to make the first step in the modelling of pharmaceutical demand in Italy, by deriving a weighted capitation model to account for demographic differences among general practices. The experimental model was called ASSET (Age/Sex Standardised Estimates of Treatment). Methods and Major Findings Individual prescription costs and demographic data referred to 3,175,691 Italian subjects and were collected directly from three Regional Health Authorities over the 12-month period between October 2004 and September 2005. The mean annual prescription cost per individual was similar for males (196.13 euro) and females (195.12 euro). After 65 years of age, the mean prescribing costs for males were significantly higher than females. On average, costs for a 75-year-old subject would be 12 times the costs for a 25–34 year-old subject if male, 8 times if female. Subjects over 65 years of age (22% of total population) accounted for 56% of total prescribing costs. The weightings explained approximately 90% of the evolution of total prescribing costs, in spite of the pricing and reimbursement turbulences affecting Italy in the 2000–2005 period. The ASSET weightings were able to explain only about 25% of the variation in prescribing costs among individuals. Conclusions If mainly idiosyncratic prescribing by general practitioners causes the unexplained variations, the introduction of capitation-based budgets would gradually move practices with high prescribing costs towards the national average. It is also possible, though, that the unexplained individual variation in prescribing costs is the result of differences in the clinical characteristics or socio-economic conditions of practice populations. If this is the case, capitation-based budgets may lead to unfair distribution of resources. The ASSET age/sex weightings should be used as a guide, not as the ultimate determinant, for an equitable allocation of prescribing resources to

  10. Age estimates and uplift rates for late Pleistocene marine terraces: Southern Oregon portion of the Cascadia forearc

    SciTech Connect

    Muhs, D.R.; Whelan, J.F. ); Kelsey, H.M.; McInelly, G.W. ); Miller, G.H. ); Kennedy, G.L. )

    1990-05-10

    Interest in the Cascadia subduction zone has increased because recent investigations have suggested that slip along plates at certain types of convergent margins is characteristically accompanied by large earthquakes. In addition, other investigations have suggested that convergent margins can be broadly classified by the magnitude of their uplift rates. The authors generated new uranium series, amino acid, and stable isotope data for southern Oregon marine terrace fossils. These data, along with terrace elevations and two alternative estimates of sea level at the time of terrace formation, allow one to determine terrace ages and uplift rates. Uranium series analysis of fossil coral yields an age of 83 {plus minus} 5 ka for the Whisky Run terrace at Coquille Point in Bandon, Oregon. A combination of amino acid and oxygen isotope data suggest ages of about 80 and 105 ka for the lowest two terraces at Cape Blanco. These ages indicate uplift rates of 0.45-1.05 and 0.81-1.49 m/kyr for Coquille Point and Cape Blanco, respectively. In order to assess the utility of the southern Oregon uplift rates for predicting the behavior of the Cascadia subduction zone, the authors compared late Quaternary uplift rates derived from terrace data from subduction zones around the world. On the basis of this comparison the southern Oregon rates of vertical deformation are not usually high or low. Furthermore, late Quaternary uplift rates show little relationship to the type of convergent margin. In the case of the southern Oregon coast, variability in uplift rate probably reflects local structures in the overriding plate, and the rate of uplift cannot be used as a simple index of the potential for great earthquakes along the southern Cascadia subduction zone.

  11. Evaluation of economic effects of population ageing--methodology of estimating indirect costs.

    PubMed

    Schubert, Agata; Czech, Marcin; Gębska-Kuczerowska, Anita

    2015-01-01

    Process of demographic ageing, especially in recent decades, is steadily growing in dynamics and importance due to increasing health-related needs and expectations with regard to a guarantee of social services. Elaboration of the most effective model of care, tailored to Polish conditions, requires an estimation of actual costs of this care, including indirect costs which are greatly related to informal care. The fact that the costs of informal care are omitted, results from a determined approach to analyses. It is discussed only from a perspective of budget for health and does not cover societal aspects. In such situation, however, the costs borne by a receiver of services are neglected. As a consequence, the costs of informal care are underestimated or often excluded from calculations, even if they include indirect costs. Comprehensive methodological approach for estimating the costs of informal care seems to be important for a properly conducted economic evaluation in health care sector.

  12. Demirjian's system for estimating the dental age of northeastern Brazilian children.

    PubMed

    Maia, Maria Cristina Germano; Martins, Maria da Gloria Almeida; Germano, Francisco Alcides; Brandão Neto, Jose; da Silva, Carlos Antonio Bruno

    2010-07-15

    Since Demirjian's system of estimating dental maturity was first described, many researchers from different countries have tested its accuracy among diverse populations. Some of these studies have pointed out a need to determine population-specific standards. In Brazil, the Northeast region is the one that most suffers the negative impact of exodus, specially related to the increase of abandoned children in the cities. The aim of this study was to test the accuracy of Demirjian's system for assessing the dental maturity of northeastern Brazilian children, so as to present a scale for maturity score conversion into dental age developed specifically for this population. This could be used for forensic, anthropological and legal matters, and also as a model for other countries attempting to formulate their own conversion scales. Panoramic radiographs of 1,491 children (821 females and 670 males), aged 7 to 13 years, from Ceará state, northeast Brazil, were assessed by a single observer to determine dental age (DA) according to Demirjian's system. The mean percentage of intra-observer agreement was 86.6%, with a mean Cohen's Kappa coefficient of 0.67 (substantial agreement). The DA was compared by paired t-test to subjects' chronological age (CA). The differences between CA and DA in all age groups were statistically significant (p<0.0001), demonstrating a great advancement in DA among Brazilians. Scatter plots were drawn for both genders, and the data were fitted to a growth curve, y=100/(1+e(-a(x)-(b))). Graphs corresponding to the 50(th) percentile curves were produced. A table with new values for the conversion of maturity score into dental age for northeastern Brazilian children is presented. The great advancement in DA, as obtained by Demirjian's system in this population, justified the determination of specific scores for dental maturity assessment.

  13. Estimation of mechanical properties of cast stainless steels during thermal aging in LWR systems

    SciTech Connect

    Chopra, O.K.

    1991-10-01

    A procedure and correlations are presented for predicting Charpy- impact energy, tensile flow stress, fracture toughness J-R curve, and J{sub IC} of aged cast stainless steels from known material information. The ``saturation`` impact strength and fracture toughness of a specific cast stainless steel, i.e., the minimum value that would be achieved for the material after long-term service, is estimated from the chemical composition of the steel. Mechanical properties as a function of time and temperature of reactor service are estimated from impact energy and flow stress of the unaged material and the kinetics of embrittlement, which are also determined from chemical composition. The J{sub IC} values are determined from the estimated J-R curve and flow stress. Examples of estimating mechanical properties of cast stainless steel components during reactor service are presented. A common ``lower-bound`` J-R curve for cast stainless steels of unknown chemical composition is also defined for a given grade of steel, ferrite content, and temperature.

  14. Estimating the value of volunteer-assisted community-based aging services: a case example.

    PubMed

    Scharlach, Andrew E

    2015-01-01

    This study demonstrates the use of a social return on investment (SROI) approach in estimating the financial and social value created by volunteer-assisted community-based aging services. An expanded value added statement (EVAS) analysis found that the total value of outputs produced by the Concierge Club of San Diego substantially exceeded the cost of the program, after considering likely secondary and tertiary benefits for a range of affected stakeholders-including elderly service recipients, family members, volunteers, and societal institutions. Additional research is needed regarding the direct and indirect costs and benefits of volunteer support services for vulnerable older adults and their families.

  15. Estimating the value of volunteer-assisted community-based aging services: a case example.

    PubMed

    Scharlach, Andrew E

    2015-01-01

    This study demonstrates the use of a social return on investment (SROI) approach in estimating the financial and social value created by volunteer-assisted community-based aging services. An expanded value added statement (EVAS) analysis found that the total value of outputs produced by the Concierge Club of San Diego substantially exceeded the cost of the program, after considering likely secondary and tertiary benefits for a range of affected stakeholders-including elderly service recipients, family members, volunteers, and societal institutions. Additional research is needed regarding the direct and indirect costs and benefits of volunteer support services for vulnerable older adults and their families. PMID:25551169

  16. Estimation of the age at onset in spinocerebellar ataxia type 2 Cuban patients by survival analysis.

    PubMed

    Almaguer-Mederos, L E; Falcón, N S; Almira, Y R; Zaldivar, Y G; Almarales, D C; Góngora, E M; Herrera, M P; Batallán, K E; Armiñán, R R; Manresa, M V; Cruz, G S; Laffita-Mesa, J; Cyuz, T M; Chang, V; Auburger, G; Gispert, S; Pérez, L V

    2010-08-01

    Previous studies have investigated the close association that exists between CAG repeat number and the age at onset in SCA2 = spinocerebellar ataxia type 2. These studies have focused on affected individuals. To further characterize this association and estimate the risk of a carrier developing SCA2 at a particular age as a function of a specific CAG repeat size, we have analyzed a large group of 924 individuals, including 394 presymptomatic and 530 affected individuals with a CAG repeat length of 32-79 units. Using a Kaplan-Meier survival analysis, we obtained cumulative probability curves for disease manifestation at a particular age for each CAG repeat length in the 34-45 range. These curves were significantly different (p < 0.001) and showed small overlap. All these information may be very valuable in predictive-testing programs, in the planning of studies for the identification of other genetic and environmental factors as modifiers of age at onset, and in the design of clinical trials for people at enlarged risk for SCA2. PMID:20095980

  17. Estimation of legal age using calcification stages of third molars in living individuals.

    PubMed

    Streckbein, Philipp; Reichert, Isabelle; Verhoff, Marcel A; Bödeker, Rolf-Hasso; Kähling, Christopher; Wilbrand, Jan-Falco; Schaaf, Heidrun; Howaldt, Hans-Peter; May, Andreas

    2014-12-01

    The increased number of adolescents and young adults with unknown or inaccurately given date of birth is a current issue in justice and legal medicine. The objective of this study was to determine the extent to which third molar calcification stages assessed on panoramic X-rays could be useful as additional criteria for forensic age estimation in living individuals, focusing on the legally important ages 17 and 18. In a retrospective multi-center study, the developmental stage of each individual's third molar was analyzed using Demirjian's scale in 2360 cases. Additionally, sex, age and ancestry were assessed. Individuals with the lowest calcification stage of all present molars in stage H were ≥18 years with a likelihood of ≥99.05% in the female (n=388), and ≥99.24% in the male (n=482) population. The lowest calcification stage of all present third molars proved to be useful as an additional reliable criterion for the determination of an age ≥18 years.

  18. Age estimation in forensic sciences: Application of combined aspartic acid racemization and radiocarbon analysis

    SciTech Connect

    Alkass, K; Buchholz, B A; Ohtani, S; Yamamoto, T; Druid, H; Spalding, S L

    2009-11-02

    Age determination of unknown human bodies is important in the setting of a crime investigation or a mass disaster, since the age at death, birth date and year of death, as well as gender, can guide investigators to the correct identity among a large number of possible matches. Traditional morphological methods used by anthropologists to determine age are often imprecise, whereas chemical analysis of tooth dentin, such as aspartic acid racemization has shown reproducible and more precise results. In this paper we analyze teeth from Swedish individuals using both aspartic acid racemization and radiocarbon methodologies. The rationale behind using radiocarbon analysis is that above-ground testing of nuclear weapons during the cold war (1955-1963) caused an extreme increase in global levels of carbon-14 ({sup 14}C) which have been carefully recorded over time. Forty-four teeth from 41 individuals were analyzed using aspartic acid racemization analysis of tooth crown dentin or radiocarbon analysis of enamel and ten of these were split and subjected to both radiocarbon and racemization analysis. Combined analysis showed that the two methods correlated well (R2=0.66, p < 0.05). Radiocarbon analysis showed an excellent precision with an overall absolute error of 0.6 {+-} 04 years. Aspartic acid racemization also showed a good precision with an overall absolute error of 5.4 {+-} 4.2 years. Whereas radiocarbon analysis gives an estimated year of birth, racemization analysis indicates the chronological age of the individual at the time of death. We show how these methods in combination can also assist in the estimation of date of death of an unidentified victim. This strategy can be of significant assistance in forensic casework involving dead victim identification.

  19. Age estimation in forensic sciences: application of combined aspartic acid racemization and radiocarbon analysis.

    PubMed

    Alkass, Kanar; Buchholz, Bruce A; Ohtani, Susumu; Yamamoto, Toshiharu; Druid, Henrik; Spalding, Kirsty L

    2010-05-01

    Age determination of unknown human bodies is important in the setting of a crime investigation or a mass disaster because the age at death, birth date, and year of death as well as gender can guide investigators to the correct identity among a large number of possible matches. Traditional morphological methods used by anthropologists to determine age are often imprecise, whereas chemical analysis of tooth dentin, such as aspartic acid racemization, has shown reproducible and more precise results. In this study, we analyzed teeth from Swedish individuals using both aspartic acid racemization and radiocarbon methodologies. The rationale behind using radiocarbon analysis is that aboveground testing of nuclear weapons during the cold war (1955-1963) caused an extreme increase in global levels of carbon-14 ((14)C), which has been carefully recorded over time. Forty-four teeth from 41 individuals were analyzed using aspartic acid racemization analysis of tooth crown dentin or radiocarbon analysis of enamel, and 10 of these were split and subjected to both radiocarbon and racemization analysis. Combined analysis showed that the two methods correlated well (R(2) = 0.66, p < 0.05). Radiocarbon analysis showed an excellent precision with an overall absolute error of 1.0 +/- 0.6 years. Aspartic acid racemization also showed a good precision with an overall absolute error of 5.4 +/- 4.2 years. Whereas radiocarbon analysis gives an estimated year of birth, racemization analysis indicates the chronological age of the individual at the time of death. We show how these methods in combination can also assist in the estimation of date of death of an unidentified victim. This strategy can be of significant assistance in forensic casework involving dead victim identification.

  20. Hierarchical Bayesian approach for estimating physical properties in spiral galaxies: Age Maps for M74

    NASA Astrophysics Data System (ADS)

    Sánchez Gil, M. Carmen; Berihuete, Angel; Alfaro, Emilio J.; Pérez, Enrique; Sarro, Luis M.

    2015-09-01

    One of the fundamental goals of modern Astronomy is to estimate the physical parameters of galaxies from images in different spectral bands. We present a hierarchical Bayesian model for obtaining age maps from images in the Ha line (taken with Taurus Tunable Filter (TTF)), ultraviolet band (far UV or FUV, from GALEX) and infrared bands (24, 70 and 160 microns (μm), from Spitzer). As shown in [1], we present the burst ages for young stellar populations in the nearby and nearly face on galaxy M74. As it is shown in the previous work, the Hα to FUV flux ratio gives a good relative indicator of very recent star formation history (SFH). As a nascent star-forming region evolves, the Ha line emission declines earlier than the UV continuum, leading to a decrease in the HαFUV ratio. Through a specific star-forming galaxy model (Starburst 99, SB99), we can obtain the corresponding theoretical ratio Hα / FUV to compare with our observed flux ratios, and thus to estimate the ages of the observed regions. Due to the nature of the problem, it is necessary to propose a model of high complexity to take into account the mean uncertainties, and the interrelationship between parameters when the Hα / FUV flux ratio mentioned above is obtained. To address the complexity of the model, we propose a Bayesian hierarchical model, where a joint probability distribution is defined to determine the parameters (age, metallicity, IMF), from the observed data, in this case the observed flux ratios Hα / FUV. The joint distribution of the parameters is described through an i.i.d. (independent and identically distributed random variables), generated through MCMC (Markov Chain Monte Carlo) techniques.

  1. Age estimation in forensic sciences: application of combined aspartic acid racemization and radiocarbon analysis.

    PubMed

    Alkass, Kanar; Buchholz, Bruce A; Ohtani, Susumu; Yamamoto, Toshiharu; Druid, Henrik; Spalding, Kirsty L

    2010-05-01

    Age determination of unknown human bodies is important in the setting of a crime investigation or a mass disaster because the age at death, birth date, and year of death as well as gender can guide investigators to the correct identity among a large number of possible matches. Traditional morphological methods used by anthropologists to determine age are often imprecise, whereas chemical analysis of tooth dentin, such as aspartic acid racemization, has shown reproducible and more precise results. In this study, we analyzed teeth from Swedish individuals using both aspartic acid racemization and radiocarbon methodologies. The rationale behind using radiocarbon analysis is that aboveground testing of nuclear weapons during the cold war (1955-1963) caused an extreme increase in global levels of carbon-14 ((14)C), which has been carefully recorded over time. Forty-four teeth from 41 individuals were analyzed using aspartic acid racemization analysis of tooth crown dentin or radiocarbon analysis of enamel, and 10 of these were split and subjected to both radiocarbon and racemization analysis. Combined analysis showed that the two methods correlated well (R(2) = 0.66, p < 0.05). Radiocarbon analysis showed an excellent precision with an overall absolute error of 1.0 +/- 0.6 years. Aspartic acid racemization also showed a good precision with an overall absolute error of 5.4 +/- 4.2 years. Whereas radiocarbon analysis gives an estimated year of birth, racemization analysis indicates the chronological age of the individual at the time of death. We show how these methods in combination can also assist in the estimation of date of death of an unidentified victim. This strategy can be of significant assistance in forensic casework involving dead victim identification. PMID:19965905

  2. Population-Calibrated Gene Characterization: Estimating Age at Onset Distributions Associated With Cancer Genes

    PubMed Central

    Iversen, Edwin S.; Chen, Sining

    2008-01-01

    Phenotypic characterization of rare disease genes poses a significant statistical challenge, but the need to do so is clear. Clinical management of patients carrying a disease gene depends crucially on an accurate characterization of the genetically predisposed disease, including its likelihood of occurrence among mutation carriers, natural history, and response to treatment. We propose a formal yet practical method for controlling for bias due to ignoring ascertainment, defined as the sampling mechanism, when quantifying the association between genotype and disease using data on high-risk families. The approach is more statistically efficient than conditioning on the variables used in sampling. In it, the likelihood is adjusted by a factor that is a function of sampling weights in strata defined by those variables. It requires that these variables and the sampling probabilities in the strata they define either are known or can be estimated. The latter requires a second, population-based dataset. As an example, we derive ascertainment-corrected estimates of penetrance for the breast cancer susceptibility genes BRCA1 and BRCA2. The Bayesian analysis that we use incorporates a modified segregation model and prior data on penetrance derived from the literature. Markov chain Monte Carlo methods are used for inference. PMID:18418465

  3. Revised stratigraphy of Area 123, Koobi Fora, Kenya, and new age estimates of its fossil mammals, including hominins.

    PubMed

    Gathogo, Patrick N; Brown, Francis H

    2006-11-01

    Recent geologic study shows that all hominins and nearly all other published mammalian fossils from Paleontological Collection Area 123, Koobi Fora, Kenya, derive from levels between the KBS Tuff (1.87+/-0.02 Ma) and the Lower Ileret Tuff (1.53+/-0.01 Ma). More specifically, the fossils derive from 53 m of section below the Lower Ileret Tuff, an interval in which beds vary markedly laterally, especially those units containing molluscs and algal stromatolites. The upper Burgi Member (approximately 2.00-1.87 Ma) crops out only in the southwestern part of Area 123. Adjacent Area 110 contains larger exposures of the member, and there the KBS Tuff is preserved as an airfall ash in lacustrine deposits and also as a fluvially redeposited ash. We observed no mammalian fossils in situ in this member in Area 123, but surface specimens have been documented in some monographic treatments. Fossil hominins from Area 123 were attributed to strata above the KBS Tuff in the 1970s, but later they were assigned to strata below the KBS Tuff (now called the upper Burgi Member). This study definitively places the Area 123 hominins in the KBS Member. Most of these hominins are between 1.60 and 1.65 myr in age, but the youngest may date to only 1.53 Ma, and the oldest, to 1.75 Ma. All are 0.15-0.30 myr younger than previously estimated. The new age estimates, in conjunction with published taxonomic attributions of fossils, suggest that at least two species of Homo coexisted in the region along with A. boisei until at least 1.65 Ma. Comparison of crania KNM-ER 1813 and KNM-ER 1470, which were believed to be of comparable age, is at the focus of the debate over whether Homo habilis sensu lato is in fact composed of two species: Homo habilis and Homo rudolfensis. These two crania are separated in time by approximately 0.25 myr, and therefore, arguments for their conspecificity no longer need to confront the issue of unusually high contemporaneous variation within a single species. PMID

  4. Normal modes of the atmosphere as estimated by principal oscillation patterns and derived from quasigeostrophic theory

    SciTech Connect

    Schnur, R.; Storch, H. von ); Schmitz, G.; Grieger, N. )

    1993-08-01

    The principal oscillation pattern (POP) analysis is a technique to empirically identify time-dependent spatial patterns in a multivariate time series of geophysical or other data. In order to investigate medium-scale and synoptic waves in the atmosphere it has been applied to tropospheric geopotential height fields of ECMWF analyses from 1984 to 1987. The data have been subjected to zonal Fourier decomposition and to time filtering so that variations with periods between 3 and 25 days were retained. Analyses have been performed separately for each zonal wavenumber 5-9 on the Northern Hemisphere in winter and on the Southern Hemisphere in summer (DJF). POPs can be seen as normal modes of a linear approximation to a more complex dynamical system. The system matrix is estimated from observations of nature. This concept is compared with conventional stability analysis where the system matrix of the linear system is derived from theoretical, in this case quasigeostrophic, reasoning. Only the mean basic flow depends on time- and space-averaged fields of observed wind and temperature from the ECMWF data. It turns out that the most significant POPs are very similar in time and spatial structure to the most unstable waves in the stability analysis. They describe the linear growth phase of baroclinic, unstable waves that propagate eastward with periods of 3-7 days. Since the POPs are purely derived from observations, the results indicate the appropriateness of the assumptions usually made in linear stability analysis of zonally symmetric flows to explain high-frequency atmospheric fluctuations. Moreover, the POP analysis reveals patterns that are not found in the linear stability analysis. These can possibly be attributed to the nonlinear decay phase of baroclinic waves. Eliassen-Palm cross sections help clarify the interpretation of the POPs in terms of the life cycle of nonlinear baroclinic waves. 24 refs., 14 figs.

  5. Assessing the Congruence of Thermal Niche Estimations Derived from Distribution and Physiological Data. A Test Using Diving Beetles

    PubMed Central

    Sánchez-Fernández, David; Aragón, Pedro; Bilton, David T.; Lobo, Jorge M.

    2012-01-01

    A basic aim of ecology is to understand the determinants of organismal distribution, the niche concept and species distribution models providing key frameworks to approach the problem. As temperature is one of the most important factors affecting species distribution, the estimation of thermal limits is crucially important for inferring range constraints. It is expectable that thermal physiology data derived from laboratory experiments and species' occurrences may express different aspects of the species' niche. However, there is no study systematically testing this prediction in a given taxonomic group while controlling by potential phylogenetic inertia. We estimate the thermal niches of twelve Palaearctic diving beetles species using physiological data derived from experimental analyses in order to examine the extent to which these coincided with those estimated from distribution models based on observed occurrences. We found that thermal niche estimates derived from both approaches lack general congruence, and these results were similar before and after controlling by phylogeny. The congruence between potential distributions obtained from the two different procedures was also explored, and we found again that the percentage of agreement were not very high (∼60%). We confirm that both thermal niche estimates derived from geographical and physiological data are likely to misrepresent the true range of climatic variation that these diving beetles are able to tolerate, and so these procedures could be considered as incomplete but complementary estimations of an inaccessible reality. PMID:23133560

  6. Chemical Characterization of Beer Aging Products Derived from Hard Resin Components in Hops (Humulus lupulus L.).

    PubMed

    Taniguchi, Yoshimasa; Yamada, Makiko; Taniguchi, Harumi; Matsukura, Yasuko; Shindo, Kazutoshi

    2015-11-25

    The bitter taste of beer originates from resins in hops (Humulus lupulus L.), which are classified into two subtypes (soft and hard). Whereas the nature and reactivity of soft-resin-derived compounds, such as α-, β-, and iso-α-acids, are well studied, there is only a little information on the compounds in hard resin. For this work, hard resin was prepared from stored hops and investigated for its compositional changes in an experimental model of beer aging. The hard resin contained a series of α-acid oxides. Among them, 4'-hydroxyallohumulinones were unstable under beer storage conditions, and their transformation induced primary compositional changes of the hard resin during beer aging. The chemical structures of the products, including novel polycyclic compounds scorpiohumulinols A and B and dicyclohumulinols A and B, were determined by HRMS and NMR analyses. These compounds were proposed to be produced via proton-catalyzed cyclization reactions of 4'-hydroxyallohumulinones. Furthermore, they were more stable than their precursor 4'-hydroxyallohumulinones during prolonged storage periods.

  7. Chemical Characterization of Beer Aging Products Derived from Hard Resin Components in Hops (Humulus lupulus L.).

    PubMed

    Taniguchi, Yoshimasa; Yamada, Makiko; Taniguchi, Harumi; Matsukura, Yasuko; Shindo, Kazutoshi

    2015-11-25

    The bitter taste of beer originates from resins in hops (Humulus lupulus L.), which are classified into two subtypes (soft and hard). Whereas the nature and reactivity of soft-resin-derived compounds, such as α-, β-, and iso-α-acids, are well studied, there is only a little information on the compounds in hard resin. For this work, hard resin was prepared from stored hops and investigated for its compositional changes in an experimental model of beer aging. The hard resin contained a series of α-acid oxides. Among them, 4'-hydroxyallohumulinones were unstable under beer storage conditions, and their transformation induced primary compositional changes of the hard resin during beer aging. The chemical structures of the products, including novel polycyclic compounds scorpiohumulinols A and B and dicyclohumulinols A and B, were determined by HRMS and NMR analyses. These compounds were proposed to be produced via proton-catalyzed cyclization reactions of 4'-hydroxyallohumulinones. Furthermore, they were more stable than their precursor 4'-hydroxyallohumulinones during prolonged storage periods. PMID:26507444

  8. Meta-analysis for deriving age- and gender-specific dose-response relationships between urinary cadmium concentration and beta2-microglobulinuria under environmental exposure.

    PubMed

    Gamo, Masashi; Ono, Kyoko; Nakanishi, Junko

    2006-05-01

    A meta-analysis was conducted to derive age- and gender-specific dose-response relationships between urinary cadmium (Cd) concentration and beta2-microglobulinuria (beta2MG-uria) under environmental exposure. beta2MG-uria was defined by a cutoff point of 1000 microg beta2-microglobulin/g creatinine. We proposed a model for describing the relationships among the interindividual variabilities in urinary Cd concentration, the ratio of Cd concentrations in the target organ and in urine, and the threshold Cd concentration in the target organ. The parameters in the model were determined so that good agreement might be achieved between the prevalence rates of beta2MG-uria reported in the literature and those estimated by the model. In this analysis, only the data from the literature on populations environmentally exposed to Cd were used. Using the model and estimated parameters, the prevalence rate of beta2MG-uria can be estimated for an age- and gender-specific subpopulation for which the distribution of urinary Cd concentrations is known. The maximum permissible level of urinary Cd concentration was defined as the maximum geometric mean of the urinary Cd concentration in an age- and gender-specific subpopulation that would not result in a statistically significant increase in the prevalence rate of beta2MG-uria. This was estimated to be approximately 3 microg/g creatinine for a population in a small geographical area and approximately 2 microg/g creatinine for a nationwide population.

  9. Dental age estimation in Japanese individuals combining permanent teeth and third molars.

    PubMed

    Ramanan, Namratha; Thevissen, Patrick; Fleuws, Steffen; Willems, G

    2012-12-01

    The study aim was, firstly, to verify the Willems et al. model on a Japanese reference sample. Secondly to develop a Japanese reference model based on the Willems et al. method and to verify it. Thirdly to analyze the age prediction performance adding tooth development information of third molars to permanent teeth. Retrospectively 1877 panoramic radiographs were selected in the age range between 1 and 23 years (1248 children, 629 sub-adults). Dental development was registered applying Demirjian 's stages of the mandibular left permanent teeth in children and Köhler stages on the third molars. The children's data were, firstly, used to validate the Willems et al. model (developed a Belgian reference sample), secondly, split ino a training and a test sample. On the training sample a Japanese reference model was developed based on the Willems method. The developed model and the Willems et al; model were verified on the test sample. Regression analysis was used to detect the age prediction performance adding third molar scores to permanent tooth scores. The validated Willems et al. model provided a mean absolute error of 0.85 and 0.75 years in females and males, respectively. The mean absolute error in the verified Willems et al. and the developed Japanese reference model was 0.85, 0.77 and 0.79, 0.75 years in females and males, respectively. On average a negligible change in root mean square error values was detected adding third molar scores to permanent teeth scores. The Belgian sample could be used as a reference model to estimate the age of the Japanese individuals. Combining information from the third molars and permanent teeth was not providing clinically significant improvement of age predictions based on permanent teeth information alone. PMID:23474507

  10. Dental age estimation in Japanese individuals combining permanent teeth and third molars.

    PubMed

    Ramanan, Namratha; Thevissen, Patrick; Fleuws, Steffen; Willems, G

    2012-12-01

    The study aim was, firstly, to verify the Willems et al. model on a Japanese reference sample. Secondly to develop a Japanese reference model based on the Willems et al. method and to verify it. Thirdly to analyze the age prediction performance adding tooth development information of third molars to permanent teeth. Retrospectively 1877 panoramic radiographs were selected in the age range between 1 and 23 years (1248 children, 629 sub-adults). Dental development was registered applying Demirjian 's stages of the mandibular left permanent teeth in children and Köhler stages on the third molars. The children's data were, firstly, used to validate the Willems et al. model (developed a Belgian reference sample), secondly, split ino a training and a test sample. On the training sample a Japanese reference model was developed based on the Willems method. The developed model and the Willems et al; model were verified on the test sample. Regression analysis was used to detect the age prediction performance adding third molar scores to permanent tooth scores. The validated Willems et al. model provided a mean absolute error of 0.85 and 0.75 years in females and males, respectively. The mean absolute error in the verified Willems et al. and the developed Japanese reference model was 0.85, 0.77 and 0.79, 0.75 years in females and males, respectively. On average a negligible change in root mean square error values was detected adding third molar scores to permanent teeth scores. The Belgian sample could be used as a reference model to estimate the age of the Japanese individuals. Combining information from the third molars and permanent teeth was not providing clinically significant improvement of age predictions based on permanent teeth information alone.

  11. Photogrammetrically Derived Estimates of Glacier Mass Loss in the Upper Susitna Drainage Basin, Alaska Range, Alaska

    NASA Astrophysics Data System (ADS)

    Wolken, G. J.; Whorton, E.; Murphy, N.

    2014-12-01

    Glaciers in Alaska are currently experiencing some of the highest rates of mass loss on Earth, with mass wastage rates accelerating during the last several decades. Glaciers, and other components of the hydrologic cycle, are expected to continue to change in response to anticipated future atmospheric warming, thus, affecting the quantity and timing of river runoff. This study uses sequential digital elevation model (DEM) analysis to estimate the mass loss of glaciers in the upper Susitna drainage basin, Alaska Range, for the purpose of validating model simulations of past runoff changes. We use mainly stereo optical airborne and satellite data for several epochs between 1949 and 2014, and employ traditional stereo-photogrammetric and structure from motion processing techniques to derive DEMs of the upper Susitna basin glaciers. This work aims to improve the record of glacier change in the central Alaska Range, and serves as a critical validation dataset for a hydrological model that simulates the potential effects of future glacier mass loss on changes in river runoff over the lifespan of the proposed Susitna-Watana Hydroelectric Project.

  12. Holocene climatic change in the northern Midwest: Pollen-derived estimates

    NASA Astrophysics Data System (ADS)

    Bartlein, P. J.; Webb, T.; Fleri, E.

    1984-11-01

    Mapping of Holocene pollen data in the midwestern United States has revealed several broadscale vegetational changes that can be interpreted in climatic terms. These changes include (1) the early Holocene northward movement of the spruce-dominated forest and its later southward movement after 3000 yr B.P. and (2) the eastward movement of the prairie/forest border into southwestern Wisconsin by 8000 yr B.P. and its subsequent westward retreat after 6000 yr B.P. When certain basic assumptions are met, multiple regression models can be derived from modern pollen and climate data and used to transform the pollen record of these vegetational changes into quantitative estimates of temperature or precipitation. To maximize the reliability of the regression equations, we followed a sequence of procedures that minimize violations of the assumptions that underlie regression analysis. Reconstructions of precipitation during the Holocene indicated that from 9000 to 6000 yr B.P. precipitation decreased by 10 to 25% over much of the Midwest, while mean July temperature increased by 0.5° to 2.0°C. At 6000 yr B.P. precipitation was less than 80% of its modern values over parts of Wisconsin and Minnesota. After 6000 yr B.P. precipitation generally increased, while mean July temperature decreased in the north, and increased in the south. The time of the maximum temperature varies within the Midwest and is earlier in the north and later in the south.

  13. Dental age estimation and different predictive ability of various tooth types in the Czech population: data mining methods.

    PubMed

    Velemínská, Jana; Pilný, Ales; Cepek, Miroslav; Kot'ová, Magdaléna; Kubelková, Radka

    2013-01-01

    Dental development is frequently used to estimate age in many anthropological specializations. The aim of this study was to extract an accurate predictive age system for the Czech population and to discover any different predictive ability of various tooth types and their ontogenetic stability during infancy and adolescence. A cross-sectional panoramic X-ray study was based on developmental stages assessment of mandibular teeth (Moorrees et al. 1963) using 1393 individuals aged from 3 to 17 years. Data mining methods were used for dental age estimation. These are based on nonlinear relationships between the predicted age and data sets. Compared with other tested predictive models, the GAME method predicted age with the highest accuracy. Age-interval estimations between the 10th and 90th percentiles ranged from -1.06 to +1.01 years in girls and from -1.13 to +1.20 in boys. Accuracy was expressed by RMS error, which is the average deviation between estimated and chronological age. The predictive value of individual teeth changed during the investigated period from 3 to 17 years. When we evaluated the whole period, the second molars exhibited the best predictive ability. When evaluating partial age periods, we found that the accuracy of biological age prediction declines with increasing age (from 0.52 to 1.20 years in girls and from 0.62 to 1.22 years in boys) and that the predictive importance of tooth types changes, depending on variability and the number of developmental stages in the age interval. GAME is a promising tool for age-interval estimation studies as they can provide reliable predictive models. PMID:24466642

  14. A collation of recently published Western European formulae for age estimation of subadult skeletal remains: recommendations for forensic anthropology and osteoarchaeology.

    PubMed

    Rissech, Carme; Márquez-Grant, Nicholas; Turbón, Daniel

    2013-01-01

    The aim of this study is to provide an effective and quick reference guide based on the most useful European formulae recently published for subadult age estimation. All of these formulae derive from studies on postnatal growth of the scapula, innominate, femur, and tibia, based on modern skeletal data (173 ♂, 173 ♀) from five documented collections from Spain, Portugal, and Britain. The formulae were calculated from Inverse Regression. For this reason, these formulae are especially useful for modern samples from Western Europe and in particular on 20th century human remains from the Iberian Peninsula. Eleven formulae were selected as the most useful because they can be applied to individuals from within a wide age range and in individuals of unknown sex. Due to their high reliability and because they derive from documented European skeletal samples, we recommend these formulae be used on individuals of Caucasoid ancestry from Western Europe.

  15. Improving artificial forest biomass estimates using afforestation age information from time series Landsat stacks.

    PubMed

    Liu, Liangyun; Peng, Dailiang; Wang, Zhihui; Hu, Yong

    2014-11-01

    China maintains the largest artificial forest area in the world. Studying the dynamic variation of forest biomass and carbon stock is important to the sustainable use of forest resources and understanding of the artificial forest carbon budget in China. In this study, we investigated the potential of Landsat time series stacks for aboveground biomass (AGB) estimation in Yulin District, a key region of the Three-North Shelter region of China. Firstly, the afforestation age was successfully retrieved from the Landsat time series stacks in the last 40 years (from 1974 to 2013) and shown to be consistent with the surveyed tree ages, with a root-mean-square error (RMSE) value of 4.32 years and a determination coefficient (R (2)) of 0.824. Then, the AGB regression models were successfully developed by integrating vegetation indices and tree age. The simple ratio vegetation index (SR) is the best candidate of the commonly used vegetation indices for estimating forest AGB, and the forest AGB model was significantly improved using the combination of SR and tree age, with R (2) values from 0.50 to 0.727. Finally, the forest AGB images were mapped at eight epochs from 1985 to 2013 using SR and afforestation age. The total forest AGB in seven counties of Yulin District increased by 20.8 G kg, from 5.8 G kg in 1986 to 26.6 G kg in 2013, a total increase of 360 %. For the persistent forest area since 1974, the forest AGB density increased from 15.72 t/ha in 1986 to 44.53 t/ha in 2013, with an annual rate of about 0.98 t/ha. For the artificial forest planted after 1974, the AGB density increased about 1.03 t/ha a year from 1974 to 2013. The results present a noticeable carbon increment for the planted artificial forest in Yulin District over the last four decades.

  16. Estimation of age based on tooth cementum annulations: A comparative study using light, polarized, and phase contrast microscopy

    PubMed Central

    Kaur, Prabhpreet; Astekar, Madhusudan; Singh, Jappreet; Arora, Karandeep Singh; Bhalla, Gagandeep

    2015-01-01

    Context: The identification of living or deceased persons using unique traits and characteristics of the teeth and jaws is a cornerstone of forensic science. Teeth have been used to estimate age both in the young and old, as well as in the living and dead. Gradual structural changes in teeth throughout life are the basis for age estimation. Tooth cementum annulation (TCA) is a microscopic method for the determination of an individual's age based on the analysis of incremental lines of cementum. Aim: To compare ages estimated using incremental lines of cementum as visualized by bright field microscopy, polarized microscopy, and phase contrast microscopy with the actual age of subject and to determine accuracy and feasibility of the method used. Materials and Methods: Cementum annulations of 60 permanent teeth were analyzed after longitudinal ground sections were made in the mesiodistal plane. The incremental lines were counted manually using a light, polarized and phase contrast microscopy. Ages were estimated and then compared with the actual age of individual. Statistical Analysis: Analysis of variance (ANOVA), Student's t-test, the Pearson product-moment corre (PPMCC) and regression analysis were performed. Results: PPMCC value r = 0.347, 0.542 and 0.989 were obtained using light, polarized and phase contrast microscopy methods respectively. Conclusion: It was concluded that incremental lines of cementum were most clearly visible under a phase contrast microscope, followed by a polarized microscope, and then a light microscope when used for age estimation. PMID:26816462

  17. Estimating age ratios and size of pacific walrus herds on coastal haulouts using video imaging.

    PubMed

    Monson, Daniel H; Udevitz, Mark S; Jay, Chadwick V

    2013-01-01

    During Arctic summers, sea ice provides resting habitat for Pacific walruses as it drifts over foraging areas in the eastern Chukchi Sea. Climate-driven reductions in sea ice have recently created ice-free conditions in the Chukchi Sea by late summer causing walruses to rest at coastal haulouts along the Chukotka and Alaska coasts, which provides an opportunity to study walruses at relatively accessible locations. Walrus age can be determined from the ratio of tusk length to snout dimensions. We evaluated use of images obtained from a gyro-stabilized video system mounted on a helicopter flying at high altitudes (to avoid disturbance) to classify the sex and age of walruses hauled out on Alaska beaches in 2010-2011. We were able to classify 95% of randomly selected individuals to either an 8- or 3-category age class, and we found measurement-based age classifications were more repeatable than visual classifications when using images presenting the correct head profile. Herd density at coastal haulouts averaged 0.88 walruses/m(2) (std. err. = 0.02), herd size ranged from 8,300 to 19,400 (CV 0.03-0.06) and we documented ∼30,000 animals along ∼1 km of beach in 2011. Within the herds, dependent walruses (0-2 yr-olds) tended to be located closer to water, and this tendency became more pronounced as the herd spent more time on the beach. Therefore, unbiased estimation of herd age-ratios will require a sampling design that allows for spatial and temporal structuring. In addition, randomly sampling walruses available at the edge of the herd for other purposes (e.g., tagging, biopsying) will not sample walruses with an age structure representative of the herd. Sea ice losses are projected to continue, and population age structure data collected with aerial videography at coastal haulouts may provide demographic information vital to ongoing efforts to understand effects of climate change on this species. PMID:23936106

  18. Estimating age ratios and size of Pacific walrus herds on coastal haulouts using video imaging

    USGS Publications Warehouse

    Monson, Daniel H.; Udevitz, Mark S.; Jay, Chadwick V.

    2013-01-01

    During Arctic summers, sea ice provides resting habitat for Pacific walruses as it drifts over foraging areas in the eastern Chukchi Sea. Climate-driven reductions in sea ice have recently created ice-free conditions in the Chukchi Sea by late summer causing walruses to rest at coastal haulouts along the Chukotka and Alaska coasts, which provides an opportunity to study walruses at relatively accessible locations. Walrus age can be determined from the ratio of tusk length to snout dimensions. We evaluated use of images obtained from a gyro-stabilized video system mounted on a helicopter flying at high altitudes (to avoid disturbance) to classify the sex and age of walruses hauled out on Alaska beaches in 2010–2011. We were able to classify 95% of randomly selected individuals to either an 8- or 3-category age class, and we found measurement-based age classifications were more repeatable than visual classifications when using images presenting the correct head profile. Herd density at coastal haulouts averaged 0.88 walruses/m2 (std. err. = 0.02), herd size ranged from 8,300 to 19,400 (CV 0.03–0.06) and we documented ~30,000 animals along ~1 km of beach in 2011. Within the herds, dependent walruses (0–2 yr-olds) tended to be located closer to water, and this tendency became more pronounced as the herd spent more time on the beach. Therefore, unbiased estimation of herd age-ratios will require a sampling design that allows for spatial and temporal structuring. In addition, randomly sampling walruses available at the edge of the herd for other purposes (e.g., tagging, biopsying) will not sample walruses with an age structure representative of the herd. Sea ice losses are projected to continue, and population age structure data collected with aerial videography at coastal haulouts may provide demographic information vital to ongoing efforts to understand effects of climate change on this species.

  19. Estimating age ratios and size of pacific walrus herds on coastal haulouts using video imaging.

    PubMed

    Monson, Daniel H; Udevitz, Mark S; Jay, Chadwick V

    2013-01-01

    During Arctic summers, sea ice provides resting habitat for Pacific walruses as it drifts over foraging areas in the eastern Chukchi Sea. Climate-driven reductions in sea ice have recently created ice-free conditions in the Chukchi Sea by late summer causing walruses to rest at coastal haulouts along the Chukotka and Alaska coasts, which provides an opportunity to study walruses at relatively accessible locations. Walrus age can be determined from the ratio of tusk length to snout dimensions. We evaluated use of images obtained from a gyro-stabilized video system mounted on a helicopter flying at high altitudes (to avoid disturbance) to classify the sex and age of walruses hauled out on Alaska beaches in 2010-2011. We were able to classify 95% of randomly selected individuals to either an 8- or 3-category age class, and we found measurement-based age classifications were more repeatable than visual classifications when using images presenting the correct head profile. Herd density at coastal haulouts averaged 0.88 walruses/m(2) (std. err. = 0.02), herd size ranged from 8,300 to 19,400 (CV 0.03-0.06) and we documented ∼30,000 animals along ∼1 km of beach in 2011. Within the herds, dependent walruses (0-2 yr-olds) tended to be located closer to water, and this tendency became more pronounced as the herd spent more time on the beach. Therefore, unbiased estimation of herd age-ratios will require a sampling design that allows for spatial and temporal structuring. In addition, randomly sampling walruses available at the edge of the herd for other purposes (e.g., tagging, biopsying) will not sample walruses with an age structure representative of the herd. Sea ice losses are projected to continue, and population age structure data collected with aerial videography at coastal haulouts may provide demographic information vital to ongoing efforts to understand effects of climate change on this species.

  20. Estimating Age Ratios and Size of Pacific Walrus Herds on Coastal Haulouts using Video Imaging

    PubMed Central

    Monson, Daniel H.; Udevitz, Mark S.; Jay, Chadwick V.

    2013-01-01

    During Arctic summers, sea ice provides resting habitat for Pacific walruses as it drifts over foraging areas in the eastern Chukchi Sea. Climate-driven reductions in sea ice have recently created ice-free conditions in the Chukchi Sea by late summer causing walruses to rest at coastal haulouts along the Chukotka and Alaska coasts, which provides an opportunity to study walruses at relatively accessible locations. Walrus age can be determined from the ratio of tusk length to snout dimensions. We evaluated use of images obtained from a gyro-stabilized video system mounted on a helicopter flying at high altitudes (to avoid disturbance) to classify the sex and age of walruses hauled out on Alaska beaches in 2010–2011. We were able to classify 95% of randomly selected individuals to either an 8- or 3-category age class, and we found measurement-based age classifications were more repeatable than visual classifications when using images presenting the correct head profile. Herd density at coastal haulouts averaged 0.88 walruses/m2 (std. err. = 0.02), herd size ranged from 8,300 to 19,400 (CV 0.03–0.06) and we documented ∼30,000 animals along ∼1 km of beach in 2011. Within the herds, dependent walruses (0–2 yr-olds) tended to be located closer to water, and this tendency became more pronounced as the herd spent more time on the beach. Therefore, unbiased estimation of herd age-ratios will require a sampling design that allows for spatial and temporal structuring. In addition, randomly sampling walruses available at the edge of the herd for other purposes (e.g., tagging, biopsying) will not sample walruses with an age structure representative of the herd. Sea ice losses are projected to continue, and population age structure data collected with aerial videography at coastal haulouts may provide demographic information vital to ongoing efforts to understand effects of climate change on this species. PMID:23936106

  1. Estimating risks of heat strain by age and sex: a population-level simulation model.

    PubMed

    Glass, Kathryn; Tait, Peter W; Hanna, Elizabeth G; Dear, Keith

    2015-05-18

    Individuals living in hot climates face health risks from hyperthermia due to excessive heat. Heat strain is influenced by weather exposure and by individual characteristics such as age, sex, body size, and occupation. To explore the population-level drivers of heat strain, we developed a simulation model that scales up individual risks of heat storage (estimated using Myrup and Morgan's man model "MANMO") to a large population. Using Australian weather data, we identify high-risk weather conditions together with individual characteristics that increase the risk of heat stress under these conditions. The model identifies elevated risks in children and the elderly, with females aged 75 and older those most likely to experience heat strain. Risk of heat strain in males does not increase as rapidly with age, but is greatest on hot days with high solar radiation. Although cloudy days are less dangerous for the wider population, older women still have an elevated risk of heat strain on hot cloudy days or when indoors during high temperatures. Simulation models provide a valuable method for exploring population level risks of heat strain, and a tool for evaluating public health and other government policy interventions.

  2. Image analysis of pubic bone for age estimation in a computed tomography sample.

    PubMed

    López-Alcaraz, Manuel; González, Pedro Manuel Garamendi; Aguilera, Inmaculada Alemán; López, Miguel Botella

    2015-03-01

    Radiology has demonstrated great utility for age estimation, but most of the studies are based on metrical and morphological methods in order to perform an identification profile. A simple image analysis-based method is presented, aimed to correlate the bony tissue ultrastructure with several variables obtained from the grey-level histogram (GLH) of computed tomography (CT) sagittal sections of the pubic symphysis surface and the pubic body, and relating them with age. The CT sample consisted of 169 hospital Digital Imaging and Communications in Medicine (DICOM) archives of known sex and age. The calculated multiple regression models showed a maximum R (2) of 0.533 for females and 0.726 for males, with a high intra- and inter-observer agreement. The method suggested is considered not only useful for performing an identification profile during virtopsy, but also for application in further studies in order to attach a quantitative correlation for tissue ultrastructure characteristics, without complex and expensive methods beyond image analysis.

  3. Estimating Risks of Heat Strain by Age and Sex: A Population-Level Simulation Model

    PubMed Central

    Glass, Kathryn; Tait, Peter W.; Hanna, Elizabeth G.; Dear, Keith

    2015-01-01

    Individuals living in hot climates face health risks from hyperthermia due to excessive heat. Heat strain is influenced by weather exposure and by individual characteristics such as age, sex, body size, and occupation. To explore the population-level drivers of heat strain, we developed a simulation model that scales up individual risks of heat storage (estimated using Myrup and Morgan’s man model “MANMO”) to a large population. Using Australian weather data, we identify high-risk weather conditions together with individual characteristics that increase the risk of heat stress under these conditions. The model identifies elevated risks in children and the elderly, with females aged 75 and older those most likely to experience heat strain. Risk of heat strain in males does not increase as rapidly with age, but is greatest on hot days with high solar radiation. Although cloudy days are less dangerous for the wider population, older women still have an elevated risk of heat strain on hot cloudy days or when indoors during high temperatures. Simulation models provide a valuable method for exploring population level risks of heat strain, and a tool for evaluating public health and other government policy interventions. PMID:25993102

  4. Real-time algebraic derivative estimations using a novel low-cost architecture based on reconfigurable logic.

    PubMed

    Morales, Rafael; Rincón, Fernando; Gazzano, Julio Dondo; López, Juan Carlos

    2014-01-01

    Time derivative estimation of signals plays a very important role in several fields, such as signal processing and control engineering, just to name a few of them. For that purpose, a non-asymptotic algebraic procedure for the approximate estimation of the system states is used in this work. The method is based on results from differential algebra and furnishes some general formulae for the time derivatives of a measurable signal in which two algebraic derivative estimators run simultaneously, but in an overlapping fashion. The algebraic derivative algorithm presented in this paper is computed online and in real-time, offering high robustness properties with regard to corrupting noises, versatility and ease of implementation. Besides, in this work, we introduce a novel architecture to accelerate this algebraic derivative estimator using reconfigurable logic. The core of the algorithm is implemented in an FPGA, improving the speed of the system and achieving real-time performance. Finally, this work proposes a low-cost platform for the integration of hardware in the loop in MATLAB. PMID:24859033

  5. Real-Time Algebraic Derivative Estimations Using a Novel Low-Cost Architecture Based on Reconfigurable Logic

    PubMed Central

    Morales, Rafael; Rincón, Fernando; Gazzano, Julio Dondo; López, Juan Carlos

    2014-01-01

    Time derivative estimation of signals plays a very important role in several fields, such as signal processing and control engineering, just to name a few of them. For that purpose, a non-asymptotic algebraic procedure for the approximate estimation of the system states is used in this work. The method is based on results from differential algebra and furnishes some general formulae for the time derivatives of a measurable signal in which two algebraic derivative estimators run simultaneously, but in an overlapping fashion. The algebraic derivative algorithm presented in this paper is computed online and in real-time, offering high robustness properties with regard to corrupting noises, versatility and ease of implementation. Besides, in this work, we introduce a novel architecture to accelerate this algebraic derivative estimator using reconfigurable logic. The core of the algorithm is implemented in an FPGA, improving the speed of the system and achieving real-time performance. Finally, this work proposes a low-cost platform for the integration of hardware in the loop in MATLAB. PMID:24859033

  6. Space-time derivative estimates of the Koch-Tataru solutions to the nematic liquid crystal system in Besov spaces

    NASA Astrophysics Data System (ADS)

    Liu, Qiao

    2015-06-01

    In recent paper [7], Y. Du and K. Wang (2013) proved that the global-in-time Koch-Tataru type solution (u, d) to the n-dimensional incompressible nematic liquid crystal flow with small initial data (u0, d0) in BMO-1 × BMO has arbitrary space-time derivative estimates in the so-called Koch-Tataru space norms. The purpose of this paper is to show that the Koch-Tataru type solution satisfies the decay estimates for any space-time derivative involving some borderline Besov space norms.

  7. [Estimation of the biological age in males of the taiga tick (Ixodes persulcatus: Ixodinae) by fat reserves in the midgut].

    PubMed

    Grigor'eva, L A

    2012-01-01

    Some criteria for the estimation of the biological and calendar age by the fat storage in midgut cells of Ixodes persulcatus males were established on the basis of examination of ticks from the laboratory culture.

  8. Estimation of individual age and season of death in woolly rhinoceros, Coelodonta antiquitatis (Blumenbach, 1799), from Sakha-Yakutia, Russia

    NASA Astrophysics Data System (ADS)

    Kirillova, Irina V.; Shidlovskiy, Fedor K.

    2010-11-01

    A unique find of a woolly rhinoceros skull bearing both nasal and frontal horns is described from a thermokarst lake of the Bol'shaya Chukoch'ya River basin in north-eastern Republic of Sakha (Yakutia), Russia. Based on counts of cementum layers of the maxillary first molar and dark and transverse bands of the nasal and frontal horns a correlation of individual age records within these structures is established. Both estimations of individual age are agreed as well as three other age estimation criteria followed from cranial characteristics, general aspects of dentition and tooth wear pattern. Thus, the number of horn bands, which is equal to 30 or 31, does express the individual age at the moment when the woolly rhinoceros died. The tooth cementum and both horns are proved to be recording structures of woolly rhinoceroses which can be used as precise individual age estimation criteria. The season in which death occurred is also discussed.

  9. Applicability of Greulich-Pyle and Tanner-Whitehouse grading methods to MRI when assessing hand bone age in forensic age estimation: A pilot study.

    PubMed

    Urschler, Martin; Krauskopf, Astrid; Widek, Thomas; Sorantin, Erich; Ehammer, Thomas; Borkenstein, Martin; Yen, Kathrin; Scheurer, Eva

    2016-09-01

    Determination of skeletal development is a key pillar in forensic age estimation of living persons. Radiological assessment of hand bone age is widely used until the age of about 17-18 years, applying visual grading techniques to hand radiographs. This study investigated whether Greulich-Pyle (GP) and Tanner-Whitehouse (TW2) grading can be equally used for magnetic resonance imaging (MRI) data, which would offer the huge benefit of avoiding ionizing radiation. In 18 subjects aged between 7 and 17 years a radiograph and an MRI scan of the hand were performed. Epiphyseal ossification of hand bones was rated by two blinded radiologists with both GP and TW2. Correlation between hand MRIs and radiographs was analyzed by linear regression and inter-observer agreement was assessed. Correlation between age estimates from MRI and radiographs was high for both GP (r(2)=0.98) and TW2 (r(2)=0.93). MRI showed a tendency to estimate age slightly lower for 14-18 year-olds, which would be favorable regarding majority age determination in case this result could be reproduced using a currently not existing reference estimation method based on MRI data. Inter-observer agreement was similar for GP in radiographs and MRI, while for TW2, agreement in MRI was lower than in radiographs. In spite of limitations regarding sample size and recruited subjects, our results indicate that the use of GP and TW2 on MRI data offers the possibility of hand bone age estimation without the need for ionizing radiation. PMID:27344264

  10. Applicability of Greulich-Pyle and Tanner-Whitehouse grading methods to MRI when assessing hand bone age in forensic age estimation: A pilot study.

    PubMed

    Urschler, Martin; Krauskopf, Astrid; Widek, Thomas; Sorantin, Erich; Ehammer, Thomas; Borkenstein, Martin; Yen, Kathrin; Scheurer, Eva

    2016-09-01

    Determination of skeletal development is a key pillar in forensic age estimation of living persons. Radiological assessment of hand bone age is widely used until the age of about 17-18 years, applying visual grading techniques to hand radiographs. This study investigated whether Greulich-Pyle (GP) and Tanner-Whitehouse (TW2) grading can be equally used for magnetic resonance imaging (MRI) data, which would offer the huge benefit of avoiding ionizing radiation. In 18 subjects aged between 7 and 17 years a radiograph and an MRI scan of the hand were performed. Epiphyseal ossification of hand bones was rated by two blinded radiologists with both GP and TW2. Correlation between hand MRIs and radiographs was analyzed by linear regression and inter-observer agreement was assessed. Correlation between age estimates from MRI and radiographs was high for both GP (r(2)=0.98) and TW2 (r(2)=0.93). MRI showed a tendency to estimate age slightly lower for 14-18 year-olds, which would be favorable regarding majority age determination in case this result could be reproduced using a currently not existing reference estimation method based on MRI data. Inter-observer agreement was similar for GP in radiographs and MRI, while for TW2, agreement in MRI was lower than in radiographs. In spite of limitations regarding sample size and recruited subjects, our results indicate that the use of GP and TW2 on MRI data offers the possibility of hand bone age estimation without the need for ionizing radiation.

  11. Comparison of emissions estimates derived from atmospheric measurements with national estimates of HFCs, PFCs and SF6.

    PubMed

    Harnisch, Jochen; Höhne, Niklas

    2002-01-01

    This paper assesses the feasibility of using atmospheric measurement of fluorinated greenhouse gases (HFCs, PFCs and SF6) for the review and verification of greenhouse gas inventories provided by national governments. For this purpose, available data were compiled. It was found that atmospheric measurements of these gases are available and provide an indication of global annual emissions with sufficient certainty to reach the following conclusions: Within the uncertainty of the method, it was found that emissions of HFC-23, a by-product of HCFC-22 production, as obtained from atmospheric measurements did not decrease as fast, as the countries have reported. In contrast, SF6 concentrations in the atmosphere suggest higher emissions than reported by countries. Regional emission estimates from atmospheric measurements are still in a more pioneering state and cannot be compared to national estimates. Intensified efforts to measure HFCs, PFCs and SF6 in the atmosphere are recommended. PMID:12391806

  12. Age estimation in children by measurement of open apices in tooth roots: Study of a Mexican sample.

    PubMed

    De Luca, Stefano; De Giorgio, Stefania; Butti, Andrea Carlo; Biagi, Roberto; Cingolani, Mariano; Cameriere, Roberto

    2012-09-10

    The aim of this cross-sectional study was to test the accuracy of Cameriere's European formula for age assessment in a large sample of Mexican children. The accuracy of dental age estimation was defined as how closely real age, measured as the difference between chronological age (CA) and dental age (DA), could be predicted. Digitalized orthopantomographs of 502 Mexican children (254 girls and 248 boys), aged between 5 and 15 years, were analyzed. The seven left permanent mandibular teeth were evaluated using Cameriere's method. Intra- and inter-observer variability for this technique was tested on a small random sample. Dental age was estimated for each individual and compared with known chronological age. Accuracy was measured as the difference between known chronological age and dental age and tested for significance with the mean prediction error (ME). The standard deviation and 95% confidence interval of the mean difference were also calculated. ME was 0.63 years for girls and 0.52 years for boys. ME was found to be slightly overestimated by 0.10 years for girls, but was correctly estimated for boys with an accuracy of 0.00. In conclusion, this method is very useful and may be recommended for practical application both in clinical dentistry and forensic procedures on the Mexican population.

  13. Differences among estimates of critical power and anaerobic work capacity derived from five mathematical models and the three-minute all-out test.

    PubMed

    Bergstrom, Haley C; Housh, Terry J; Zuniga, Jorge M; Traylor, Daniel A; Lewis, Robert W; Camic, Clayton L; Schmidt, Richard J; Johnson, Glen O

    2014-03-01

    Estimates of critical power (CP) and anaerobic work capacity (AWC) from the power output vs. time relationship have been derived from various mathematical models. The purpose of this study was to examine estimates of CP and AWC from the multiple work bout, 2- and 3-parameter models, and those from the 3-minute all-out CP (CP3min) test. Nine college-aged subjects performed a maximal incremental test to determine the peak oxygen consumption rate and the gas exchange threshold. On separate days, each subject completed 4 randomly ordered constant power output rides to exhaustion to estimate CP and AWC from 5 regression models (2 linear, 2 nonlinear, and 1 exponential). During the final visit, CP and AWC were estimated from the CP3min test. The nonlinear 3-parameter (Nonlinear-3) model produced the lowest estimate of CP. The exponential (EXP) model and the CP3min test were not statistically different and produced the highest estimates of CP. Critical power estimated from the Nonlinear-3 model was 14% less than those from the EXP model and the CP3min test and 4-6% less than those from the linear models. Furthermore, the Nonlinear-3 and nonlinear 2-parameter (Nonlinear-2) models produced significantly greater estimates of AWC than did the linear models and CP3min. The current findings suggested that the Nonlinear-3 model may provide estimates of CP and AWC that more accurately reflect the asymptote of the power output vs. time relationship, the demarcation of the heavy and severe exercise intensity domains, and anaerobic capabilities than will the linear models and CP3min test.

  14. Phenotype, donor age and gender affect function of human bone marrow-derived mesenchymal stromal cells

    PubMed Central

    2013-01-01

    Background Mesenchymal stromal cells (MSCs) are attractive for cell-based therapies ranging from regenerative medicine and tissue engineering to immunomodulation. However, clinical efficacy is variable and it is unclear how the phenotypes defining bone marrow (BM)-derived MSCs as well as donor characteristics affect their functional properties. Methods BM-MSCs were isolated from 53 (25 female, 28 male; age: 13 to 80 years) donors and analyzed by: (1) phenotype using flow cytometry and cell size measurement; (2) in vitro growth kinetics using population doubling time; (3) colony formation capacity and telomerase activity; and (4) function by in vitro differentiation capacity, suppression of T cell proliferation, cytokines and trophic factors secretion, and hormone and growth factor receptor expression. Additionally, expression of Oct4, Nanog, Prdm14 and SOX2 mRNA was compared to pluripotent stem cells. Results BM-MSCs from younger donors showed increased expression of MCAM, VCAM-1, ALCAM, PDGFRβ, PDL-1, Thy1 and CD71, and led to lower IL-6 production when co-cultured with activated T cells. Female BM-MSCs showed increased expression of IFN-γR1 and IL-6β, and were more potent in T cell proliferation suppression. High-clonogenic BM-MSCs were smaller, divided more rapidly and were more frequent in BM-MSC preparations from younger female donors. CD10, β1integrin, HCAM, CD71, VCAM-1, IFN-γR1, MCAM, ALCAM, LNGFR and HLA ABC were correlated to BM-MSC preparations with high clonogenic potential and expression of IFN-γR1, MCAM and HLA ABC was associated with rapid growth of BM-MSCs. The mesodermal differentiation capacity of BM-MSCs was unaffected by donor age or gender but was affected by phenotype (CD10, IFN-γR1, GD2). BM-MSCs from female and male donors expressed androgen receptor and FGFR3, and secreted VEGF-A, HGF, LIF, Angiopoietin-1, basic fibroblast growth factor (bFGF) and NGFB. HGF secretion correlated negatively to the expression of CD71, CD140b and

  15. Estimating winter wheat biomass by assimilating leaf area index derived from fusion of Landsat-8 and MODIS data

    NASA Astrophysics Data System (ADS)

    Dong, Taifeng; Liu, Jiangui; Qian, Budong; Zhao, Ting; Jing, Qi; Geng, Xiaoyuan; Wang, Jinfei; Huffman, Ted; Shang, Jiali

    2016-07-01

    A sufficient number of satellite acquisitions in a growing season are essential for deriving agronomic indicators, such as green leaf area index (GLAI), to be assimilated into crop models for crop productivity estimation. However, for most high resolution orbital optical satellites, it is often difficult to obtain images frequently due to their long revisit cycles and unfavorable weather conditions. Data fusion algorithms, such as the Spatial and Temporal Adaptive Reflectance Fusion Model (STARFM) and the Enhanced STARFM (ESTARFM), have been developed to generate synthetic data with high spatial and temporal resolution to address this issue. In this study, we evaluated the approach of assimilating GLAI into the Simple Algorithm for Yield Estimation model (SAFY) for winter wheat biomass estimation. GLAI was estimated using the two-band Enhanced Vegetation Index (EVI2) derived from data acquired by the Operational Land Imager (OLI) onboard the Landsat-8 and a fusion dataset generated by blending the Moderate-Resolution Imaging Spectroradiometer (MODIS) data and the OLI data using the STARFM and ESTARFM models. The fusion dataset had the temporal resolution of the MODIS data and the spatial resolution of the OLI data. Key parameters of the SAFY model were optimised through assimilation of the estimated GLAI into the crop model using the Shuffled Complex Evolution-University of Arizona (SCE-UA) algorithm. A good agreement was achieved between the estimated and field measured biomass by assimilating the GLAI derived from the OLI data (GLAIL) alone (R2 = 0.77 and RMSE = 231 g m-2). Assimilation of GLAI derived from the fusion dataset (GLAIF) resulted in a R2 of 0.71 and RMSE of 193 g m-2 while assimilating the combination of GLAIL and GLAIF led to further improvements (R2 = 0.76 and RMSE = 176 g m-2). Our results demonstrated the potential of using the fusion algorithms to improve crop growth monitoring and crop productivity estimation when the number of high resolution

  16. Reducing Uncertainties in Satellite-derived Forest Aboveground Biomass Estimates using a High Resolution Forest Cover Map

    NASA Astrophysics Data System (ADS)

    Zhang, G.; Ganguly, S.; Nemani, R. R.; Milesi, C.; Basu, S.; Kumar, U.

    2014-12-01

    Several studies to date have provided an extensive knowledge base for estimating forest aboveground biomass (AGB) and recent advances in space-based modeling of the 3-D canopy structure, combined with canopy reflectance measured by passive optical sensors and radar backscatter, are providing improved satellite-derived AGB density mapping for large scale carbon monitoring applications. A key limitation in forest AGB estimation from remote sensing, however, is the large uncertainty in forest cover estimates from the coarse-to-medium resolution satellite-derived land cover maps (present resolution is limited to 30-m of the USGS NLCD Program). The uncertainties in forest cover estimates at the Landsat scale result in high uncertainties for AGB estimation, predominantly in heterogeneous forest and urban landscapes. We have successfully developed an approach using a machine learning algorithm and High-Performance-Computing with NAIP air-borne imagery data for mapping tree cover at 1-m over California and Maryland. In a comparison with high resolution LiDAR data available over selected regions in the two states, we found our results to be promising both in terms of accuracy as well as our ability to scale nationally. The generated 1-m forest cover map will be aggregated to the Landsat spatial grid to demonstrate differences in AGB estimates (pixel-level AGB density, total AGB at aggregated scales like ecoregions and counties) when using a native 30-m forest cover map versus a 30-m map derived from a higher resolution dataset. The process will also be complemented with a LiDAR derived AGB estimate at the 30-m scale to aid in true validation.

  17. Age estimation in forensic anthropology: quantification of observer error in phase versus component-based methods.

    PubMed

    Shirley, Natalie R; Ramirez Montes, Paula Andrea

    2015-01-01

    The purpose of this study was to assess observer error in phase versus component-based scoring systems used to develop age estimation methods in forensic anthropology. A method preferred by forensic anthropologists in the AAFS was selected for this evaluation (the Suchey-Brooks method for the pubic symphysis). The Suchey-Brooks descriptions were used to develop a corresponding component-based scoring system for comparison. Several commonly used reliability statistics (kappa, weighted kappa, and the intraclass correlation coefficient) were calculated to assess observer agreement between two observers and to evaluate the efficacy of each of these statistics for this study. The linear weighted kappa was determined to be the most suitable measure of observer agreement. The results show that a component-based system offers the possibility for more objective scoring than a phase system as long as the coding possibilities for each trait do not exceed three states of expression, each with as little overlap as possible.

  18. The Utility of the Proximal Epiphysis of the Fifth Metatarsal in Age Estimation

    PubMed Central

    Davies, Catriona M; Hackman, Lucina; Black, Sue

    2013-01-01

    Abstract Radiographs of 277 living individuals were assessed via a numerical scoring system to determine the timing of appearance and degree of fusion between the proximal epiphysis of the fifth metatarsal and its diaphysis. The epiphysis was observed to first appear in females at 8 years and 10 years in males and fuse by 14 years in females and 15 years in males. When assessing the level of agreement of category assignment, inter-observer agreement was 78% for females and 64% for males whereas intra-observer agreement was 77% for females and 86.1% for males. These results suggest that the maturation of the proximal epiphysis of the fifth metatarsal may be of value in age estimation in the child and that the scoring system is sufficiently robust to merit continued investigation. Previously this epiphysis has been considered an inconstant feature, but this research confirmed its presence in all individuals studied. PMID:23425260

  19. Steady state estimation of soil organic carbon using satellite-derived canopy leaf area index

    SciTech Connect

    Fang, Yilin; Liu, Chongxuan; Huang, Maoyi; Li, Hongyi; Leung, Lai-Yung R.

    2014-12-02

    Soil organic carbon (SOC) plays a key role in the global carbon cycle that is important for decadal-to-century climate prediction. Estimation of soil organic carbon stock using model-based methods typically requires spin-up (time marching transient simulation) of the carbon-nitrogen (CN) models by performing hundreds to thousands years long simulations until the carbon-nitrogen pools reach dynamic steady-state. This has become a bottleneck for global modeling and analysis, especially when testing new physical and/or chemical mechanisms and evaluating parameter sensitivity. Here we report a new numerical approach to estimate global soil carbon stock that can avoid the long term spin-up of the CN model. The approach uses canopy leaf area index (LAI) from satellite data and takes advantage of a reaction-based biogeochemical module NGBGC (Next Generation BioGeoChemical Module) that was recently developed and incorporated in version 4 of the Community Land Model (CLM4). Although NGBGC uses the same CN mechanisms as used in CLM4CN, it can be easily configured to run prognostic or steady state simulations. In this approach, monthly LAI from the multi-year Moderate Resolution Imaging Spectroradiometer (MODIS) data was used to calculate potential annual average gross primary production (GPP) and leaf carbon for the period of the atmospheric forcing. The calculated potential annual average GPP and leaf C are then used by NGBGC to calculate the steady-state distributions of carbon and nitrogen in different vegetation and soil pools by solving the steady-state reaction-network in NGBGC using the Newton-Raphson method. The new approach was applied at point and global scales and compared with SOC derived from long spin-up by running NGBGC in prognostic mode, and SOC from the empirical data of the Harmonized World Soil Database (HWSD). The steady-state solution is comparable to the spin-up value when the MODIS LAI is close to the LAI from the spin-up solution, and largely

  20. Steady state estimation of soil organic carbon using satellite-derived canopy leaf area index

    DOE PAGES

    Fang, Yilin; Liu, Chongxuan; Huang, Maoyi; Li, Hongyi; Leung, Lai-Yung R.

    2014-12-02

    Soil organic carbon (SOC) plays a key role in the global carbon cycle that is important for decadal-to-century climate prediction. Estimation of soil organic carbon stock using model-based methods typically requires spin-up (time marching transient simulation) of the carbon-nitrogen (CN) models by performing hundreds to thousands years long simulations until the carbon-nitrogen pools reach dynamic steady-state. This has become a bottleneck for global modeling and analysis, especially when testing new physical and/or chemical mechanisms and evaluating parameter sensitivity. Here we report a new numerical approach to estimate global soil carbon stock that can avoid the long term spin-up of themore » CN model. The approach uses canopy leaf area index (LAI) from satellite data and takes advantage of a reaction-based biogeochemical module NGBGC (Next Generation BioGeoChemical Module) that was recently developed and incorporated in version 4 of the Community Land Model (CLM4). Although NGBGC uses the same CN mechanisms as used in CLM4CN, it can be easily configured to run prognostic or steady state simulations. In this approach, monthly LAI from the multi-year Moderate Resolution Imaging Spectroradiometer (MODIS) data was used to calculate potential annual average gross primary production (GPP) and leaf carbon for the period of the atmospheric forcing. The calculated potential annual average GPP and leaf C are then used by NGBGC to calculate the steady-state distributions of carbon and nitrogen in different vegetation and soil pools by solving the steady-state reaction-network in NGBGC using the Newton-Raphson method. The new approach was applied at point and global scales and compared with SOC derived from long spin-up by running NGBGC in prognostic mode, and SOC from the empirical data of the Harmonized World Soil Database (HWSD). The steady-state solution is comparable to the spin-up value when the MODIS LAI is close to the LAI from the spin-up solution, and largely

  1. Age-related and stand-wise estimates of carbon stocks and sequestration in the aboveground coarse wood biomass of wetland forests in the northern Pantanal, Brazil

    NASA Astrophysics Data System (ADS)

    Schöngart, J.; Arieira, J.; Felfili Fortes, C.; Cezarine de Arruda, E.; Nunes da Cunha, C.

    2011-11-01

    In this study we use allometric models combined with tree ring analysis to estimate carbon stocks and sequestration in the aboveground coarse wood biomass (AGWB) of wetland forests in the Pantanal, located in central South America. In four 1-ha plots in stands characterized by the pioneer tree species Vochysia divergens Pohl (Vochysiaceae) forest inventories (trees ≥10 cm diameter at breast height, D) have been performed and converted to estimates of AGWB by two allometric models using three independent parameters (D, tree height H and wood density ρ). We perform a propagation of measurement errors to estimate uncertainties in the estimates of AGWB. Carbon stocks of AGWB vary from 7.8 ± 1.5 to 97.2 ± 14.4 Mg C ha-1 between the four stands. From models relating tree ages determined by dendrochronological techniques to C-stocks in AGWB we derived estimates for C-sequestration which differs from 0.50 ± 0.03 to 3.34 ± 0.31 Mg C ha-1 yr-1. Maps based on geostatistic techniques indicate the heterogeneous spatial distribution of tree ages and C-stocks of the four studied stands. This distribution is the result of forest dynamics due to the colonizing and retreating of V. divergens and other species associated with pluriannual wet and dry episodes in the Pantanal, respectively. Such information is essential for the management of the cultural landscape of the Pantanal wetlands.

  2. Contribution of Quantitative Methods of Estimating Mortality Dynamics to Explaining Mechanisms of Aging.

    PubMed

    Shilovsky, G A; Putyatina, T S; Markov, A V; Skulachev, V P

    2015-12-01

    Accumulation of various types of unrepaired damage of the genome because of increasing production of reactive oxygen species and decreasing efficiency of the antioxidant defense system and repair systems can cause age-related diseases and emergence of phenotypic signs of senescence. This should lead to increasing vulnerability and to mortality monotonously increasing with age independently of the position of the species on the evolutionary tree. In this light, the survival, mortality, and fertility curves for 45 animal and plant species and one alga published by the Max Planck Institute for Demographic Research (Germany/Denmark) are of special interest (Jones, O. R., et al. (2014) Nature, 505, 169-173). We divided all species treated in that study into four groups according to the ratio of mortality at the terminal age (which corresponds to 5% survival) and average mortality during the entire studied period. For animals of group IV (long-lived and senescent), including humans, the Jones method makes it possible to trace mortality during the entire life cycle. The same applies to short-lived animals (e.g. nematodes or the tundra vole), whether they display the Gompertz type of senescence or not. However, in long-lived species with a less pronounced increase in mortality with age (e.g. the freshwater crocodile, hermit crab, or Scots pine), as well as in animals of average lifespan that reach the terminal age earlier than they could have enough time to become senescent, the Jones method is capable of characterizing only a small part of the life cycle and does not allow judging how senescence manifests itself at late stages of the life cycle. Thus, it is known that old trees display signs of biological senescence rather clearly; although Jones et al. consider them non-senescent organisms because less than 5% of sexually mature individuals survive to display the first manifestations of these characters. We have concluded that the classification proposed by Jones et al

  3. Dental age estimation in living individuals using 3.0 T MRI of lower third molars.

    PubMed

    Guo, Yucheng; Olze, Andreas; Ottow, Christian; Schmidt, Sven; Schulz, Ronald; Heindel, Walter; Pfeiffer, Heidi; Vieth, Volker; Schmeling, Andreas

    2015-11-01

    In order to increase the validity of age estimation in adolescents and young adults when there is no legitimation for X-ray examinations, it seems desirable to be able to assess the mineralization of third molars using X-ray-free imaging procedures. In the present study, the mineralization stages of lower third molars were determined prospectively in 269 male and 248 female individuals aged 12 to 24 years using 3.0 T MRI. The classification system of Demirjian et al. was used to determine the stages. This study presents the minima and maxima, means and standard deviations, median values, and lower and upper quartiles separately for both sexes, for the mineralization stages B-H. Statistically significant sex differences were observed for the mineralization stages C, E, F, and G, and a faster developmental rate was observed for males. It was concluded that magnetic resonance imaging is an X-ray-free alternative to orthopantomography when assessing mineralization of third molars.

  4. High-Resolution Satellite-Derived PM2.5 from Optimal Estimation and Geographically Weighted Regression over North America.

    PubMed

    van Donkelaar, Aaron; Martin, Randall V; Spurr, Robert J D; Burnett, Richard T

    2015-09-01

    We used a geographically weighted regression (GWR) statistical model to represent bias of fine particulate matter concentrations (PM2.5) derived from a 1 km optimal estimate (OE) aerosol optical depth (AOD) satellite retrieval that used AOD-to-PM2.5 relationships from a chemical transport model (CTM) for 2004-2008 over North America. This hybrid approach combined the geophysical understanding and global applicability intrinsic to the CTM relationships with the knowledge provided by observational constraints. Adjusting the OE PM2.5 estimates according to the GWR-predicted bias yielded significant improvement compared with unadjusted long-term mean values (R(2) = 0.82 versus R(2) = 0.62), even when a large fraction (70%) of sites were withheld for cross-validation (R(2) = 0.78) and developed seasonal skill (R(2) = 0.62-0.89). The effect of individual GWR predictors on OE PM2.5 estimates additionally provided insight into the sources of uncertainty for global satellite-derived PM2.5 estimates. These predictor-driven effects imply that local variability in surface elevation and urban emissions are important sources of uncertainty in geophysical calculations of the AOD-to-PM2.5 relationship used in satellite-derived PM2.5 estimates over North America, and potentially worldwide. PMID:26261937

  5. High-Resolution Satellite-Derived PM2.5 from Optimal Estimation and Geographically Weighted Regression over North America.

    PubMed

    van Donkelaar, Aaron; Martin, Randall V; Spurr, Robert J D; Burnett, Richard T

    2015-09-01

    We used a geographically weighted regression (GWR) statistical model to represent bias of fine particulate matter concentrations (PM2.5) derived from a 1 km optimal estimate (OE) aerosol optical depth (AOD) satellite retrieval that used AOD-to-PM2.5 relationships from a chemical transport model (CTM) for 2004-2008 over North America. This hybrid approach combined the geophysical understanding and global applicability intrinsic to the CTM relationships with the knowledge provided by observational constraints. Adjusting the OE PM2.5 estimates according to the GWR-predicted bias yielded significant improvement compared with unadjusted long-term mean values (R(2) = 0.82 versus R(2) = 0.62), even when a large fraction (70%) of sites were withheld for cross-validation (R(2) = 0.78) and developed seasonal skill (R(2) = 0.62-0.89). The effect of individual GWR predictors on OE PM2.5 estimates additionally provided insight into the sources of uncertainty for global satellite-derived PM2.5 estimates. These predictor-driven effects imply that local variability in surface elevation and urban emissions are important sources of uncertainty in geophysical calculations of the AOD-to-PM2.5 relationship used in satellite-derived PM2.5 estimates over North America, and potentially worldwide.

  6. Age estimation of immature human skeletal remains using the post-natal development of the occipital bone.

    PubMed

    Cardoso, H F V; Gomes, J; Campanacho, V; Marinho, L

    2013-09-01

    Whenever age cannot be estimated from dental formation in immature human skeletal remains, other methods are required. In the post-natal period, development of the skeleton provides alternative age indicators, namely, those associated with skeletal maturity of the cranium. This study wishes to document the age at which the various ossification centres in the occipital bone fuse and provide readily available developmental probabilistic information for use in age estimation. A sample of 64 identified immature skeletons between birth and 8 years of age from the Lisbon collection was used (females = 29, males = 35). Results show that fusion occurs first in the posterior intra-occipital synchondrosis and between the jugular and condylar limbs of the lateral occipital to form the hypoglossal canal (1-4 years), followed by the anterior intra-occipital (3-7 years). Fusion of the post-natal occipital does not show differences in timing between males and females. Relative to other published sources, this study documents first and last ages of fusion of several ossification centres and the posterior probabilities of age given a certain stage of fusion. Given the least amount of overlap in stages of fusion, the closure of the hypoglossal canal provides the narrowest estimated age with the highest probability of age.

  7. Effects of donors' age and passage number on the biological characteristics of menstrual blood-derived stem cells.

    PubMed

    Chen, Jinyang; Du, Xiaochun; Chen, Qian; Xiang, Charlie

    2015-01-01

    We investigated the effects of donor age and passage number on the biological characteristics of menstrual blood-derived stem cells (MenSCs) by comparing MenSCs derived from donors with three different age ranges and after different passage times. Continuous passage, flat cloning, cell proliferation assays, flow cytometric phenotyping and whole human genome microarray were performed to systematically analyze the relationship between the self-renewal ability of MenSCs as well as their potential to maintain their stem cell characteristics and to resist aging. The results demonstrated that the immunophenotypes and in vitro cultural characteristics of MenSCs did not change significantly with the progression of aging. However, some important signal pathways including MAPK, the insulin signaling pathway, pathways involved in carcinogenesis such as PPAR and P53, and cytokines and their receptors, as well as other pathways associated with immune response and aging, changed to various extents under the conditions of aging after a long time in vitro. The enriched differentially-expressed genes were mainly involved in transcriptional regulation, stress response, cell proliferation, development and apoptosis. The key differentially-expressed genes associated with age and passage number were identified for use as biomarkers of cell aging.

  8. Effects of donors' age and passage number on the biological characteristics of menstrual blood-derived stem cells.

    PubMed

    Chen, Jinyang; Du, Xiaochun; Chen, Qian; Xiang, Charlie

    2015-01-01

    We investigated the effects of donor age and passage number on the biological characteristics of menstrual blood-derived stem cells (MenSCs) by comparing MenSCs derived from donors with three different age ranges and after different passage times. Continuous passage, flat cloning, cell proliferation assays, flow cytometric phenotyping and whole human genome microarray were performed to systematically analyze the relationship between the self-renewal ability of MenSCs as well as their potential to maintain their stem cell characteristics and to resist aging. The results demonstrated that the immunophenotypes and in vitro cultural characteristics of MenSCs did not change significantly with the progression of aging. However, some important signal pathways including MAPK, the insulin signaling pathway, pathways involved in carcinogenesis such as PPAR and P53, and cytokines and their receptors, as well as other pathways associated with immune response and aging, changed to various extents under the conditions of aging after a long time in vitro. The enriched differentially-expressed genes were mainly involved in transcriptional regulation, stress response, cell proliferation, development and apoptosis. The key differentially-expressed genes associated with age and passage number were identified for use as biomarkers of cell aging. PMID:26823782

  9. Evaluation of small area crop estimation techniques using LANDSAT- and ground-derived data. [South Dakota

    NASA Technical Reports Server (NTRS)

    Amis, M. L.; Martin, M. V.; Mcguire, W. G.; Shen, S. S. (Principal Investigator)

    1982-01-01

    Studies completed in fiscal year 1981 in support of the clustering/classification and preprocessing activities of the Domestic Crops and Land Cover project. The theme throughout the study was the improvement of subanalysis district (usually county level) crop hectarage estimates, as reflected in the following three objectives: (1) to evaluate the current U.S. Department of Agriculture Statistical Reporting Service regression approach to crop area estimation as applied to the problem of obtaining subanalysis district estimates; (2) to develop and test alternative approaches to subanalysis district estimation; and (3) to develop and test preprocessing techniques for use in improving subanalysis district estimates.

  10. Multivariate methods for the analysis of complex and big data in forensic sciences. Application to age estimation in living persons.

    PubMed

    Lefèvre, Thomas; Chariot, Patrick; Chauvin, Pierre

    2016-09-01

    Researchers handle increasingly higher dimensional datasets, with many variables to explore. Such datasets pose several problems, since they are difficult to handle and present unexpected features. As dimensionality increases, classical statistical analysis becomes inoperative. Variables can present redundancy, and the reduction of dataset dimensionality to its lowest possible value is often needed. Principal components analysis (PCA) has proven useful to reduce dimensionality but present several shortcomings. As others, forensic sciences will face the issues specific related to an evergrowing quantity of data to be integrated. Age estimation in living persons, an unsolved problem so far, could benefit from the integration of various sources of data, e.g., clinical, dental and radiological data. We present here novel multivariate techniques (nonlinear dimensionality reduction techniques, NLDR), applied to a theoretical example. Results were compared to those of PCA. NLDR techniques were then applied to clinical, dental and radiological data (13 variables) used for age estimation. The correlation dimension of these data was estimated. NLDR techniques outperformed PCA results. They showed that two living persons sharing similar characteristics may present rather different estimated ages. Moreover, data presented a very high informational redundancy, i.e., a correlation dimension of 2. NLDR techniques should be used with or preferred to PCA techniques to analyze complex and big data. Data routinely used for age estimation may not be considered suitable for this purpose. How integrating other data or approaches could improve age estimation in living persons is still uncertain.

  11. Altered serum glyceraldehyde-derived advanced glycation end product (AGE) and soluble AGE receptor levels indicate carbonyl stress in patients with schizophrenia.

    PubMed

    Takeda, Mayu; Ohnuma, Tohru; Takeuchi, Masayoshi; Katsuta, Narimasa; Maeshima, Hitoshi; Takebayashi, Yuto; Higa, Motoyuki; Nakamura, Toru; Nishimon, Shohei; Sannohe, Takahiro; Hotta, Yuri; Hanzawa, Ryo; Higashiyama, Ryoko; Shibata, Nobuto; Gohda, Tomohito; Suzuki, Yusuke; Yamagishi, Sho-ichi; Tomino, Yasuhiko; Arai, Heii

    2015-04-23

    Recent cross-sectional and longitudinal studies indicate that measurements of peripheral blood carbonyl stress markers such as the advanced glycation end product (AGE) pentosidine and the reactive carbonyl-detoxifying B6 vitamin pyridoxal could be used as therapeutic biological markers in subpopulations of schizophrenia patients. Glyceraldehyde-derived AGEs (Glycer-AGE) have strong neurotoxicity, and soluble receptors for AGEs (sRAGE) may ameliorate the effects of AGEs. In the present study, we measured Glycer-AGEs and sRAGE levels to determine their potential as diagnostic, therapeutic, or clinical biological markers in patients with schizophrenia. After enrollment of 61 admitted Japanese patients with acute schizophrenia and 39 healthy volunteers, 54 patients were followed up from the acute stage to remission. Serum biomarkers were measured in blood samples taken before breakfast using competitive enzyme-linked immunosorbent assays, and Glycer-AGEs were significantly higher and sRAGE levels were significantly lower in patients with acute schizophrenia than in healthy controls. Glycer-AGEs/sRAGE ratios were also higher in schizophrenia patients and were stable during the clinical course. Furthermore, discriminant analyses confirmed that Glycer-AGEs and Glycer-AGEs/sRAGE ratios are significant diagnostic markers for schizophrenia, and distinguished between patients and healthy controls in 70.0% of cases. However, these markers of carbonyl stress were not correlated with clinical features, including disease severity, or with daily chlorpromazine doses. These data indicate the potential of Glycer-AGEs, RAGEs, and their relative ratios as diagnostic markers for patients with schizophrenia.

  12. Grid-based estimates of stellar ages in binary systems. SCEPtER: Stellar CharactEristics Pisa Estimation gRid

    NASA Astrophysics Data System (ADS)

    Valle, G.; Dell'Omodarme, M.; Prada Moroni, P. G.; Degl'Innocenti, S.

    2015-07-01

    Aims: We investigate the performance of grid-based techniques in estimating the age of stars in detached eclipsing binary systems. We evaluate the precision of the estimates due to the uncertainty in the observational constraints - masses, radii, effective temperatures, and [Fe/H] - and the systematic bias caused by the uncertainty in convective core overshooting, element diffusion, mixing-length value, and initial helium content. Methods: We adopted the SCEPtER grid, which includes stars with mass in the range [0.8; 1.6] M⊙ and evolutionary stages from the zero-age main sequence to the central hydrogen depletion. Age estimates have been obtained by a generalisation of the maximum likelihood technique described in our previous work. Results: We showed that the typical 1σ random error in age estimates - due only to the uncertainty affecting the observational constraints - is about ± 7%, which is nearly independent of the masses of the two stars. However, such an error strongly depends on the evolutionary phase and becomes larger and asymmetric for stars near the zero-age main sequence where it ranges from about + 90% to -25%. The systematic bias due to the including convective core overshooting - for mild and strong overshooting scenarios - is about 50% and 120% of the error due to observational uncertainties. A variation of ± 1 in the helium-to-metal enrichment ratio ΔY/ ΔZ accounts for about ± 150% of the random error. The neglect of microscopic diffusion accounts for a bias of about 60% of the error due to observational uncertainties. We also introduced a statistical test of the expected difference in the recovered age of two coeval stars in a binary system. We find that random fluctuations within the current observational uncertainties can lead genuine coeval binary components to appear to be non-coeval with a difference in age as high as 60%. Appendix A is available in electronic form at http://www.aanda.org

  13. Accuracy of Cameriere, Haavikko, and Willems radiographic methods on age estimation on Bosnian-Herzegovian children age groups 6-13.

    PubMed

    Galić, Ivan; Vodanović, Marin; Cameriere, Roberto; Nakaš, Enita; Galić, Elizabeta; Selimović, Edin; Brkić, Hrvoje

    2011-03-01

    The aim of this cross-sectional study was to compare the accuracy of the Cameriere European formula (Cameriere), adopted Haavikko method from 1974 (Haavikko), and revisited Demirjian method by Willems (Willems) for age estimation on orthopantomograms (OPGs) of Bosnian-Herzegovian (BH) children age groups 6-13 years. The accuracy was determined as difference between estimated dental age (DA) and chronological age (CA) and the absolute accuracy (absolute difference) was assessed by analyzing OPGs of 591 girls and 498 boys. The Cameriere method overestimated the mean age by 0.09 year for girls and underestimated by -0.02 year for boys. The Haavikko method underestimated the mean age by -0.29 year for girls and -0.09 year for boys. The Willems method overestimated the mean age by 0.24 year in girls and by 0.42 year in boys. The absolute accuracies were 0.53 year for girls and 0.55 year for boys for Cameriere method; for Haavikko method, 0.59 year for girls and 0.62 year for boys; and for Willems method 0.69 year for girls and 0.67 year for boys. In conclusion, Cameriere method is the most accurate for estimating the age of BH children age groups 6-13 years using OPGs, following adopted Haavikko method and Willems method.

  14. Age calibration of carbonate rind thickness in late Pleistocene soils for surficial deposit age estimation, Southwest USA

    USGS Publications Warehouse

    Amoroso, L.

    2006-01-01

    Carbonate rinds have been used for cross-correlation of landforms as well as a quantitative indicator of soil age. Using the measured rind thickness of clasts found within a deposit, whose age has been independently determined, allows the construction of a calibrated surface-age proxy. Measurements were taken at sites within the Mojave Desert, the northwestern Sonoran Desert, the southern Great Basin, and the western Colorado Plateau. These sites are all within about 300 km of the intersection of the borders of the states of California, Arizona, and Nevada. In the study area, elevation varied from 200 to 1200 m, MAP was from 95 to 195 mm, and MAT was from 18.4?? to 23.3??. The calibrated proxy, while not accounting for the effects of parent material or climate on rind development, does show a strong correlation (R2 = 0.74, P < 0.05) between carbonate rind thickness and surface age for deposits of late to middle Pleistocene age. The calibrated chronosequence, rind thickness = 0.0889 + 0.0079 [surface age]), is in general valid over a large region of southwestern United States. This statistical relation suggests that parent material, climate, and elevation may not be as strong a control on carbonate accumulation as is age for younger soils.

  15. Cloud-to-Ground Lightning Estimates Derived from SSMI Microwave Remote Sensing and NLDN

    NASA Technical Reports Server (NTRS)

    Winesett, Thomas; Magi, Brian; Cecil, Daniel

    2015-01-01

    flash rate) was calculated for storms having 85 GHz PCT greater than 150 K. NLDN data was used to determine if a CG strike occurred for a storm. This probability of CG lightning was plotted as a function of minimum 85 GHz PCT and minimum 37 GHz PCT. These probabilities were used in conjunction with the linear model to estimate the CG flash rate for weaker storms with minimum 85 GHz PCTs greater than 150 K. Results from the investigation of CG lightning and passive microwave radiation signals agree with the previous research investigating total lightning and brightness temperature. Future work will take the established relationships and apply them to the decades of available DMSP data for the USA to derive a map of CG lightning flash rates. Validation of this method and uncertainty analysis will be done by comparing the derived maps of CG lightning flash rates against existing NLDN maps of CG lightning flash rates.

  16. A simple method for estimating informative node age priors for the fossil calibration of molecular divergence time analyses.

    PubMed

    Nowak, Michael D; Smith, Andrew B; Simpson, Carl; Zwickl, Derrick J

    2013-01-01

    Molecular divergence time analyses often rely on the age of fossil lineages to calibrate node age estimates. Most divergence time analyses are now performed in a Bayesian framework, where fossil calibrations are incorporated as parametric prior probabilities on node ages. It is widely accepted that an ideal parameterization of such node age prior probabilities should be based on a comprehensive analysis of the fossil record of the clade of interest, but there is currently no generally applicable approach for calculating such informative priors. We provide here a simple and easily implemented method that employs fossil data to estimate the likely amount of missing history prior to the oldest fossil occurrence of a clade, which can be used to fit an informative parametric prior probability distribution on a node age. Specifically, our method uses the extant diversity and the stratigraphic distribution of fossil lineages confidently assigned to a clade to fit a branching model of lineage diversification. Conditioning this on a simple model of fossil preservation, we estimate the likely amount of missing history prior to the oldest fossil occurrence of a clade. The likelihood surface of missing history can then be translated into a parametric prior probability distribution on the age of the clade of interest. We show that the method performs well with simulated fossil distribution data, but that the likelihood surface of missing history can at times be too complex for the distribution-fitting algorithm employed by our software tool. An empirical example of the application of our method is performed to estimate echinoid node ages. A simulation-based sensitivity analysis using the echinoid data set shows that node age prior distributions estimated under poor preservation rates are significantly less informative than those estimated under high preservation rates.

  17. Magnetically Derived Flood Recurrence Rate Estimates from Stalagmites in Southeastern Minnesota

    NASA Astrophysics Data System (ADS)

    Feinberg, J. M.; Lascu, I.; Andrade Lima, E.; Weiss, B. P.

    2012-12-01

    The magnetism of speleothems remains an untapped resource of paleoclimatic, hydrogeologic, and geomagnetic information. Similar to other deposits containing magnetic minerals, speleothems chronicle the evolution of local environmental parameters via the concentration, composition and grain size of their magnetic mineral assemblages. Here we report a novel use of scanning SQUID microscopy to calculate flood recurrence rates from an annually laminated ~500 year old stalagmite from Spring Valley Caverns (SVC) in southeastern Minnesota. Mineral and organic detritus adheres to the surface of a speleothem as flood waters recede from a cavern, and are subsequently encapsulated by calcite as drip water conditions are reestablished. Such detritus typically consists of allochthonous grains of quartz, clay, and titanomagnetite with an average grain size of ~10 μm. Larger flood layers occur on polished surfaces as dark bands that delineate stalagmite growth horizons. We use scanning SQUID microscopy (with a nominal sensitivity of 10-16 Am2) to map the presence of these flood layers by measuring the vertical component of the stray magnetic field resulting from a 1 T isothermal remanent magnetization (IRM) imparted perpendicular to a polished surface. A magnetization model of the IRM field was then obtained by inverting the field data measured 210 μm above the sample using an algorithm in the Fourier domain. By integrating the magnetic data parallel to the stalagmite growth axis we produce a time series of IRM peaks, each of which corresponds to a flooding event. We calculate an average flood recurrence rate of 5 per century for the last 500 years. This rate increases to >10 floods per century in the last century, thereby capturing the combined effects of both climate change and agricultural land-use on karst hydrogeology. These results agree with recurrence rate estimates derived from historical records, tree ring studies, and geochemical analyses of speleothems. The presence

  18. Estimates of ocean forecast error covariance derived from Hessian Singular Vectors

    NASA Astrophysics Data System (ADS)

    Smith, Kevin D.; Moore, Andrew M.; Arango, Hernan G.

    2015-05-01

    Experience in numerical weather prediction suggests that singular value decomposition (SVD) of a forecast can yield useful a priori information about the growth of forecast errors. It has been shown formally that SVD using the inverse of the expected analysis error covariance matrix to define the norm at initial time yields the Empirical Orthogonal Functions (EOFs) of the forecast error covariance matrix at the final time. Because of their connection to the 2nd derivative of the cost function in 4-dimensional variational (4D-Var) data assimilation, the initial time singular vectors defined in this way are often referred to as the Hessian Singular Vectors (HSVs). In the present study, estimates of ocean forecast errors and forecast error covariance were computed using SVD applied to a baroclinically unstable temperature front in a re-entrant channel using the Regional Ocean Modeling System (ROMS). An identical twin approach was used in which a truth run of the model was sampled to generate synthetic hydrographic observations that were then assimilated into the same model started from an incorrect initial condition using 4D-Var. The 4D-Var system was run sequentially, and forecasts were initialized from each ocean analysis. SVD was performed on the resulting forecasts to compute the HSVs and corresponding EOFs of the expected forecast error covariance matrix. In this study, a reduced rank approximation of the inverse expected analysis error covariance matrix was used to compute the HSVs and EOFs based on the Lanczos vectors computed during the 4D-Var minimization of the cost function. This has the advantage that the entire spectrum of HSVs and EOFs in the reduced space can be computed. The associated singular value spectrum is found to yield consistent and reliable estimates of forecast error variance in the space spanned by the EOFs. In addition, at long forecast lead times the resulting HSVs and companion EOFs are able to capture many features of the actual

  19. Non-parametric estimation of seasonal variations in GNSS-derived time series

    NASA Astrophysics Data System (ADS)

    Gruszczynska, Marta; Bogusz, Janusz; Klos, Anna

    2015-04-01

    The seasonal variations in GNSS station's position may arise from geophysical excitations, thermal changes combined together with hydrodynamics or various errors which, when superimposed, cause the seasonal oscillations not exactly of real geodynamical origin, but still have to be included in time series modelling. These variations with different periods included in frequency band from Chandler up to quarter-annual ones will all affect the reliability of permanent station's velocity, which in turn, strictly influences the quality of kinematic reference frames. As shown before by a number of authors, the annual (dominant) sine curve, has the amplitude and phase that both change in time due to the different reasons. In this research we focused on the determination of annual changes in GNSS-derived time series of North, East and Up components. We used here the daily position changes from PPP (Precise Point Positioning) solution obtained by JPL (Jet Propulsion Laboratory) processed in the GIPSY-OASIS software. We analyzed here more than 140 globally distributed IGS stations with the minimum data length of 3 years. The longest time series were even 17 years long (1996-2014). Each of the topocentric time series (North, East and Up) was divided into years (from January to December), then the observations gathered in the same days of year were stacked and the weighted medians obtained for all of them such that each of time series was represented by matrix of size 365xn where n is the data length. In this way we obtained the median annual signal for each of analyzed stations that was then decomposed into different frequency bands using wavelet decomposition with Meyer wavelet. We assumed here 7 levels of decomposition, with annual curve as the last approximation of it. The signal approximations made us to obtain the seasonal peaks that prevail in North, East and Up data for globally distributed stations. The analysis of annual curves, by means of non-parametric estimation

  20. Age estimates and uplift rates for Late Pleistocene marine terraces: Southern Oregon portion of the Cascadia Forearc

    NASA Astrophysics Data System (ADS)

    Muhs, Daniel R.; Kelsey, Harvey M.; Miller, Gifford H.; Kennedy, George L.; Whelan, Joseph F.; McInelly, Galan W.

    1990-05-01

    Marine terraces are prominent landforms along the southern Oregon coast, which forms part of the forearc region of the Cascadia subduction zone. Interest in the Cascadia subduction zone has increased because recent investigations have suggested that slip along plates at certain types of convergent margins is characteristically accompanied by large earthquakes. In addition, other investigations have suggested that convergent margins can be broadly classified by the magnitude of their uplift rates. With these hypotheses in mind, we generated new uranium series, amino acid, and stable isotope data for southern Oregon marine terrace fossils. These data, along with terrace elevations and two alternative estimates of sea level at the time of terrace formation, allow us to determine terrace ages and uplift rates. Uranium series analysis of fossil coral yields an age of 83±5 ka for the Whisky Run terrace at Coquille Point in Bandon, Oregon. A combination of amino acid and oxygen isotope data suggest ages of about 80 and 105 ka for the lowest two terraces at Cape Blanco. These ages indicate uplift rates of 0.45-1.05 and 0.81-1.49 m/kyr for Coquille Point and Cape Blanco, respectively. Late Quaternary uplift rates of marine terraces yield information about deformation in the overriding plate, but it is unclear if such data vary systematically with convergent margin type. In order to assess the utility of the southern Oregon uplift rates for predicting the behavior of the Cascadia subduction zone, we compared late Quaternary uplift rates derived from terrace data from subduction zones around the world. On the basis of this comparison the southern Oregon rates of vertical deformation are not unusually high or low. Furthermore, late Quaternary uplift rates show little relationship to the type of convergent margin. These observations suggest that local structures may play a large role in uplift rate variability. In addition, while the type of convergent margin may place an

  1. Family Sponsorship and Late-Age Immigration in Aging America: Revised and Expanded Estimates of Chained Migration.

    PubMed

    Carr, Stacie; Tienda, Marta

    2013-12-01

    We use the Immigrants Admitted to the United States (micro-data) supplemented with special tabulations from the Department of Homeland Security to examine how family reunification impacts the age composition of new immigrant cohorts since 1980. We develop a family migration multiplier measure for the period 1981 to 2009 that improves on prior studies by including immigrants granted legal status under the 1986 Immigration Reform and Control Act and relaxing unrealistic assumptions required by synthetic cohort measures. Results show that every 100 initiating immigrants admitted between 1981-85 sponsored an average of 260 family members; the comparable figure for initiating immigrants for the 1996-2000 cohort is 345 family members. Furthermore, the number of family migrants ages 50 and over rose from 44 to 74 per 100 initiating migrants. The discussion considers the health and welfare implications of late-age immigration in a climate of growing fiscal restraint and an aging native population. PMID:24415816

  2. Family Sponsorship and Late-Age Immigration in Aging America: Revised and Expanded Estimates of Chained Migration

    PubMed Central

    Carr, Stacie; Tienda, Marta

    2013-01-01

    We use the Immigrants Admitted to the United States (micro-data) supplemented with special tabulations from the Department of Homeland Security to examine how family reunification impacts the age composition of new immigrant cohorts since 1980. We develop a family migration multiplier measure for the period 1981 to 2009 that improves on prior studies by including immigrants granted legal status under the 1986 Immigration Reform and Control Act and relaxing unrealistic assumptions required by synthetic cohort measures. Results show that every 100 initiating immigrants admitted between 1981–85 sponsored an average of 260 family members; the comparable figure for initiating immigrants for the 1996–2000 cohort is 345 family members. Furthermore, the number of family migrants ages 50 and over rose from 44 to 74 per 100 initiating migrants. The discussion considers the health and welfare implications of late-age immigration in a climate of growing fiscal restraint and an aging native population. PMID:24415816

  3. Estimating the age structure of a buried adult population: a new statistical approach applied to archaeological digs in France.

    PubMed

    Séguy, Isabelle; Caussinus, Henri; Courgeau, Daniel; Buchet, Luc

    2013-02-01

    Paleodemographers have developed several methods for estimating the age structure of historical populations in absence of civil registration data. Starting from biological indicators alone, they use a reference population of known sex and age to assess the conditional distribution of the biological indicator given age. However, the small amount of data available and the unstable nature of the related statistical problem mean that most methods are disappointing. Using the most reliable reference data possible, we propose a simple statistical method, integrating the maximum amount of information included in the actual data, which quite significantly improves age estimates for a buried population. Here the method is applied to a French cemetery used from Late Antiquity to the end of the Early Middle Ages.

  4. Applicability of Demirjian's four methods and Willems method for age estimation in a sample of Turkish children.

    PubMed

    Akkaya, Nursel; Yilanci, Hümeyra Özge; Göksülük, Dinçer

    2015-09-01

    The aim of this study was to evaluate applicability of five dental methods including Demirjian's original, revised, four teeth, and alternate four teeth methods and Willems method for age estimation in a sample of Turkish children. Panoramic radiographs of 799 children (412 females, 387 males) aged between 2.20 and 15.99years were examined by two observers. A repeated measures ANOVA was performed to compare dental methods among gender and age groups. All of the five methods overestimated the chronological age on the average. Among these, Willems method was found to be the most accurate method, which showed 0.07 and 0.15years overestimation for males and females, respectively. It was followed by Demirjian's four teeth methods, revised and original methods. According to the results, Willems method can be recommended for dental age estimation of Turkish children in forensic applications.

  5. Radiologic assessment of third molar tooth and spheno-occipital synchondrosis for age estimation: a multiple regression analysis study.

    PubMed

    Demirturk Kocasarac, Husniye; Sinanoglu, Alper; Noujeim, Marcel; Helvacioglu Yigit, Dilek; Baydemir, Canan

    2016-05-01

    For forensic age estimation, radiographic assessment of third molar mineralization is important between 14 and 21 years which coincides with the legal age in most countries. The spheno-occipital synchondrosis (SOS) is an important growth site during development, and its use for age estimation is beneficial when combined with other markers. In this study, we aimed to develop a regression model to estimate and narrow the age range based on the radiologic assessment of third molar and SOS in a Turkish subpopulation. Panoramic radiographs and cone beam CT scans of 349 subjects (182 males, 167 females) with age between 8 and 25 were evaluated. Four-stage system was used to evaluate the fusion degree of SOS, and Demirjian's eight stages of development for calcification for third molars. The Pearson correlation indicated a strong positive relationship between age and third molar calcification for both sexes (r = 0.850 for females, r = 0.839 for males, P < 0.001) and also between age and SOS fusion for females (r = 0.814), but a moderate relationship was found for males (r = 0.599), P < 0.001). Based on the results obtained, an age determination formula using these scores was established.

  6. Modeling Bone Surface Morphology: A Fully Quantitative Method for Age-at-Death Estimation Using the Pubic Symphysis.

    PubMed

    Slice, Dennis E; Algee-Hewitt, Bridget F B

    2015-07-01

    The pubic symphysis is widely used in age estimation for the adult skeleton. Standard practice requires the visual comparison of surface morphology against criteria representing predefined phases and the estimation of case-specific age from an age range associated with the chosen phase. Known problems of method and observer error necessitate alternative tools to quantify age-related change in pubic morphology. This paper presents an objective, fully quantitative method for estimating age-at-death from the skeleton, which exploits a variance-based score of surface complexity computed from vertices obtained from a scanner sampling the pubic symphysis. For laser scans from 41 modern American male skeletons, this method produces results that are significantly associated with known age-at-death (RMSE = 17.15 years). Chronological age is predicted, therefore, equally well, if not, better, with this robust, objective, and fully quantitative method than with prevailing phase-aging systems. This method contributes to forensic casework by responding to medico-legal expectations for evidence standards.

  7. Estimation of Aerodynamic Stability Derivatives for Space Launch System and Impact on Stability Margins

    NASA Technical Reports Server (NTRS)

    Pei, Jing; Wall, John

    2013-01-01

    This paper describes the techniques involved in determining the aerodynamic stability derivatives for the frequency domain analysis of the Space Launch System (SLS) vehicle. Generally for launch vehicles, determination of the derivatives is fairly straightforward since the aerodynamic data is usually linear through a moderate range of angle of attack. However, if the wind tunnel data lacks proper corrections then nonlinearities and asymmetric behavior may appear in the aerodynamic database coefficients. In this case, computing the derivatives becomes a non-trivial task. Errors in computing the nominal derivatives could lead to improper interpretation regarding the natural stability of the system and tuning of the controller parameters, which would impact both stability and performance. The aerodynamic derivatives are also provided at off nominal operating conditions used for dispersed frequency domain Monte Carlo analysis. Finally, results are shown to illustrate that the effects of aerodynamic cross axis coupling can be neglected for the SLS configuration studied

  8. Adipose-derived mesenchymal stromal cells from aged patients with coronary artery disease keep mesenchymal stromal cell properties but exhibit characteristics of aging and have impaired angiogenic potential.

    PubMed

    Efimenko, Anastasia; Dzhoyashvili, Nina; Kalinina, Natalia; Kochegura, Tatiana; Akchurin, Renat; Tkachuk, Vsevolod; Parfyonova, Yelena

    2014-01-01

    Tissue regeneration is impaired in aged individuals. Adipose-derived mesenchymal stromal cells (ADSCs), a promising source for cell therapy, were shown to secrete various angiogenic factors and improve vascularization of ischemic tissues. We analyzed how patient age affected the angiogenic properties of ADSCs. ADSCs were isolated from subcutaneous fat tissue of patients with coronary artery disease (CAD; n = 64, 43-77 years old) and without CAD (n = 31, 2-82 years old). ADSC phenotype characterized by flow cytometry was CD90(+)/CD73(+)/CD105(+)/CD45(-)/CD31(-) for all samples, and these cells were capable of adipogenic and osteogenic differentiation. ADSCs from aged patients had shorter telomeres (quantitative reverse transcription polymerase chain reaction) and a tendency to attenuated telomerase activity. ADSC-conditioned media (ADSC-CM) stimulated capillary-like tube formation by endothelial cells (EA.hy926), and this effect significantly decreased with the age of patients both with and without CAD. Angiogenic factors (vascular endothelial growth factor, placental growth factor, hepatocyte growth factor, angiopoetin-1, and angiogenin) in ADSC-CM measured by enzyme-linked immunosorbent assay significantly decreased with patient age, whereas levels of antiangiogenic factors thrombospondin-1 and endostatin did not. Expression of angiogenic factors in ADSCs did not change with patient age (real-time polymerase chain reaction); however, gene expression of factors related to extracellular proteolysis (urokinase and its receptor, plasminogen activator inhibitor-1) and urokinase-type plasminogen activator receptor surface expression increased in ADSCs from aged patients with CAD. ADSCs from aged patients both with and without CAD acquire aging characteristics, and their angiogenic potential declines because of decreasing proangiogenic factor secretion. This could restrict the effectiveness of autologous cell therapy with ADSCs in aged patients.

  9. Spatial accounting for errors in LiDAR-derived products: Snow volume and snow water equivalent estimation

    NASA Astrophysics Data System (ADS)

    Tinkham, W. T.; Hoffman, C. M.; Falkowski, M. J.; Smith, A. M.; Link, T. E.; Marshall, H.

    2011-12-01

    Light Detection and Ranging (LiDAR) has become one of the most effective and reliable means of characterizing surface topography and vegetation structure. Most LiDAR-derived estimates such as vegetation height, snow depth, and floodplain boundaries rely on the accurate creation of digital terrain models (DTM). As a result of the importance of an accurate DTM in using LiDAR data to estimate snow depth, it is necessary to understand the variables that influence the DTM accuracy in order to assess snow depth error. A series of 4 x 4 m plots that were surveyed at 0.5 m spacing in a semi-arid catchment were used for training the Random Forests algorithm along with a series of 35 variab