Science.gov

Sample records for age estimates derived

  1. 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.

  2. MRI-derived body segment parameters of children differ from age-based estimates derived using photogrammetry.

    PubMed

    Bauer, Jeremy J; Pavol, Michael J; Snow, Christine M; Hayes, Wilson C

    2007-01-01

    Body segment parameters are required when researching joint kinetics using inverse dynamics models. However, the only regression equations for estimating pediatric body segment parameters across a wide age range were developed, using photogrammetry, based on 12 boys and have not been validated to date (Jensen, R.K., 1986. Body segment mass, radius and radius of gyration proportions of children. Journal of Biomechanics 19, 359-368). To assess whether these equations could validly be applied to girls, we asked whether body segment parameters estimated by the equations differ from parameters measured using a validated magnetic resonance imaging (MRI) method. If so, do the differences cause significant differences in joint kinetics during normal gait? Body segment parameters were estimated from axial MRIs of the left thigh and shank of 10 healthy girls (9.6 +/- 0.9 years) and compared to those from Jensen's equations. Kinematics and kinetics were collected for 10 walking trials. Extrema in hip and knee moments and powers were compared between the two sets of body segment parameters. With the exception of the shank mass center and radius of gyration, body segment parameters measured using MRI were significantly different from those estimated using regression equations. These systematic differences in body segment parameters resulted in significant differences in sagittal-plane joint moments and powers during gait. Nevertheless, it is doubtful that even the greatest differences in kinetics are practically meaningful (0.3% BW x HT and 0.7% BW x HT/s for moments and power at the hip, respectively). Therefore, body segment parameters estimated using Jensen's regression equations are a suitable substitute for more detailed anatomical imaging of 8-10-year-old girls when quantifying joint kinetics during gait.

  3. Comparing model-derived to independently-derived estimates of the source and age of groundwater, Idaho National Laboratory and vicinity, Idaho

    NASA Astrophysics Data System (ADS)

    Fisher, J. C.; Rousseau, J. P.; Bartholomay, R. C.; Rattray, G. W.

    2011-12-01

    The U.S. Geological Survey, in cooperation with the U.S. Department of Energy, evaluated a three-dimensional model of groundwater flow in the fractured basalts and interbedded sediments of the eastern Snake River Plain aquifer at and near the Idaho National Laboratory to determine if model-derived estimates of groundwater movement are consistent with: (1) results from previous studies on water chemistry type, (2) the geochemical mixing at an example well, and (3) independently-derived estimates of the average linear velocity. Simulated steady-state flow fields were analyzed using backward particle-tracking simulations that were based on a modified version of the particle tracking program MODPATH. The model adequately simulated the areal shape of the 5 microgram per liter lithium contour interpreted to represent the transition from a water type that is primarily composed of tributary valley underflow and streamflow infiltration recharge to a water type primarily composed of regional aquifer underflow. Inconsistences between model- and independently-derived estimates of water type separation in the southern portion of the model area may indicate model error, where unreasonable estimates of hydraulic conductivity result in an over displacement of tributary valley water by the relatively fast moving regional aquifer water. Sources of water at well NPR-W01 were identified using backward particle tracking, and they were compared to the relative percentages of source water chemistry determined using geochemical mass balance and mixing models. The particle tracking results show a good comparison with chemistry results for surface water sources (10 percent difference); however, regional aquifer sources were significantly overestimated by the model. The water samples used in the chemistry analysis were collected from an isolated depth interval in the upper 10 feet of the aquifer, an area likely absent of deeper regional groundwater; whereas, the simulated particles were

  4. 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.

  5. 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.

  6. Aging persons' estimates of vehicular motion.

    PubMed

    Schiff, W; Oldak, R; Shah, V

    1992-12-01

    Estimated arrival times of moving autos were examined in relation to viewer age, gender, motion trajectory, and velocity. Direct push-button judgments were compared with verbal estimates derived from velocity and distance, which were based on assumptions that perceivers compute arrival time from perceived distance and velocity. Experiment 1 showed that direct estimates of younger Ss were most accurate. Older women made the shortest (highly cautious) estimates of when cars would arrive. Verbal estimates were much lower than direct estimates, with little correlation between them. Experiment 2 extended target distances and velocities of targets, with the results replicating the main findings of Experiment 1. Judgment accuracy increased with target velocity, and verbal estimates were again poorer estimates of arrival time than direct ones, with different patterns of findings. Using verbal estimates to approximate judgments in traffic situations appears questionable.

  7. 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.

  8. Age Estimation in Forensic Sciences

    PubMed Central

    Alkass, Kanar; Buchholz, Bruce A.; Ohtani, Susumu; Yamamoto, Toshiharu; Druid, Henrik; Spalding, Kirsty L.

    2010-01-01

    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 (14C), 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 (R2 = 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

  9. 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.

  10. Juvenile age estimation from facial images.

    PubMed

    Ferguson, Eilidh; Wilkinson, Caroline

    2017-01-01

    Age determination from images can be of vital importance, particularly in cases involving suspected child sexual abuse (CSA). It is imperative to determine if an individual depicted in such an image is indeed a child, with a more concise age often sought, as this may affect the severity of offender sentencing. The aims of this study were to establish the accuracy of visual age estimation of the juvenile face in children aged between 0 and 16years and to determine if varying levels of exposure to children affected an individual's ability to assess age from the face. An online questionnaire consisting of 30 juvenile face images was created using SurveyMonkey®. The overall results suggested poor accuracy for visual age estimation of juvenile faces. The age, sex, occupation and number of children of the participants did not affect the ability to estimate age from facial images. Similarly, the sex and age of the juvenile faces did not appear to affect the accuracy of age estimation. When specific age groups are considered, sex may have an influence on age estimation, with female faces being aged more accurately in the younger age groups and male faces more accurate after the age of 11years, however this is based on a small sample. This study suggests that the accuracy of juvenile age estimation from the face alone is poor using simple visual assessment of images. Further research is required to determine exactly how age is assessed from a facial image, if there are indicators, or features in particular that lead to over- or under-estimation of juvenile age.

  11. [Biological age estimation by means of electroencephalography].

    PubMed

    Belozerova, L M

    2013-01-01

    The indices of computer electroencephalography have been estimated in 183 persons at the age of 20-89. Test-programs and the method of biological age determination by computer electroencephalography have been elaborated. We have found three subpopulations in each age group--people with slowing-down, mean and accelerated age changes rate. The proposed method of biological age determination includes standard generally established indices of computer electroencephalography.

  12. 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.

  13. 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

  14. Estimating survival rates with age-structure data

    USGS Publications Warehouse

    Udevitz, M.S.; Ballachey, B.E.

    1998-01-01

    We developed a general statistical model that provides a comprehensive framework for inference about survival rates based on standing age-structure and ages-at-death data. Previously available estimators are maximum likelihood under the general model, but they use only 1 type of data and require the assumption of a stable age structure and a known population growth rate. We used the general model to derive new survival rate estimators that use both types of data and require only the assumption of a stable age structure or a known population growth rate. Our likelihood-based approach allows use of standard model-selection procedures to test hypotheses about age-structure stability, population growth rates, and age-related patterns in survival. We used this approach to estimate survival rates for female sea otters (Enhydra lutris) in Prince William Sound, Alaska.

  15. Estimation of age by epidermal image processing.

    PubMed

    Tatsumi, S; Noda, H; Sugiyama, S

    1999-12-01

    Small pieces of human precordial skin were obtained from 266 individuals during autopsy performed in Osaka Prefecture. The area from the stratum corneum to the stratum basale in a unit area of the epidermal cross-section was extracted as a segmented area of white image by image processing. The number of pixels surrounding this area was measured in individuals of various ages, and the age-associated changes were evaluated. The number of pixels around this binary image in the epidermal cross-section showed a strong correlation with age. The number tended to decrease with an increase in age in individuals aged 20 years and above, which could be closely approximated by an exponential function. A formula for estimating age was obtained as an inverse function of the number of pixels and age, and the accuracy of estimation using this formula was examined by comparing the estimated age with the actual age. Such age-associated changes in the epidermis were considered to be closely related with increased roughening of the stratum basale, flattening of dermal papillae, and a decreased percentage of the stratum granulosum per unit area of epidermis observed by light microscopy or scanning electron microscopy.

  16. Estimating child mortality and modelling its age pattern for India.

    PubMed

    Roy, S G

    1989-06-01

    "Using data [for India] on proportions of children dead...estimates of infant and child mortality are...obtained by Sullivan and Trussell modifications of [the] Brass basic method. The estimate of child survivorship function derived after logit smoothing appears to be more reliable than that obtained by the Census Actuary. The age pattern of childhood mortality is suitably modelled by [a] Weibull function defining the probability of surviving from birth to a specified age and involving two parameters of level and shape. A recently developed linearization procedure based on [a] graphical approach is adopted for estimating the parameters of the function."

  17. 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.

  18. 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

  19. Estimated Autism Risk and Older Reproductive Age

    PubMed Central

    King, Marissa D.; Fountain, Christine; Dakhlallah, Diana

    2009-01-01

    Objectives. We sought to estimate the risk for autism associated with maternal and paternal age across successive birth cohorts. Methods. We linked birth records and autism diagnostic records from the California Department of Developmental Services for children born in California between 1992 and 2000 to calculate the risk associated with maternal and paternal age for each birth cohort as well as for the pooled data. Results. The categorical risks associated with maternal age over 40 years ranged from a high of 1.84 (95% confidence interval [CI] = 1.37, 2.47) to a low of 1.27 (95% CI = 0.95, 1.69). The risk associated with paternal age ranged from 1.29 (95% CI = 1.03, 1.6) to 1.71 (95% CI = 1.41, 2.08). Conclusions. Pooling data across multiple birth cohorts inflates the risk associated with paternal age. Analyses that do not suffer from problems produced by pooling across birth cohorts demonstrated that advanced maternal age, rather than paternal age, may pose greater risk. Future research examining parental age as a risk factor must be careful to avoid the paradoxes that can arise from pooling data, particularly during periods of social demographic change. PMID:19608957

  20. 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

  1. Estimating the Age of the Hawaiian Hotspot

    NASA Astrophysics Data System (ADS)

    Scholl, D. W.; Rea, D. K.

    2002-12-01

    INTRODUCTION: West of the Hawaii hotspot (HHS), an age-progressing chain of seamounts extends northwestwardly ~3600 km to the Hawaii-Emperor bend, beyond which the chain continues for ~2200 km as the north-northwestwardly trending Emperor Ridge. The ridge terminates at the ~82-Myr-old Meiji Seamount, which is perched atop the outer slope of the Kuril-Kamchatka Trench. West of Meiji, at Cape Kronotsky, the ridge orthogonally disappears into the Kamchatka subduction zone. If the length of the subducted sector of the Emperor Ridge could be estimated, then the age when volcanism began above the HHS could be estimated. MEIJI DRIFT: Deposition of the Meiji drift deposits along the northern side of the far northern or Meiji-Detroit sector of the Emperor Ridge provides a way to estimate the minimum age of the HHS. The drift deposit (as thick as 1800 m) began to accumulate about 33.5 Ma (earliest Oligocene) during the Earth's climatic transition to the ice house world. South-bound abyssal currents exiting the Bering Sea Basin, possibly generated there by thermohaline circulation, deposited the drift along the ridge sector. At this time, the sector receiving drift deposits was positioned at least 2200 km SE of its present Kamchatka trench location. Also at this time, the Aleutian Ridge (arc) cordoning the Bering Sea from the north Pacific was at least 1000 km shorter than its present length, which has been greatly lengthened during the past 50 Myr by plate boundary, transform faulting. Thus, in the early Oligocene, a wide western seaway connected abyssal circulation between the Bering Sea and north Pacific Basins. MINIMUM AGE ESTIMATING: Initiation of drift deposition requires that a former continuation of the Meiji-Detroit seamount sector, referred to here as the Obruchev continuation, crossed the north Pacific and forced abyssal currents arriving from the Bering Sea to flow eastward along the continuation's northern flank. To deflect south-bound abyssal currents, the

  2. 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.

  3. Utilization of bone impedance for age estimation in postmortem cases.

    PubMed

    Ishikawa, Noboru; Suganami, Hideki; Nishida, Atsushi; Miyamori, Daisuke; Kakiuchi, Yasuhiro; Yamada, Naotake; Wook-Cheol, Kim; Kubo, Toshikazu; Ikegaya, Hiroshi

    2015-11-01

    In the field of Forensic Medicine the number of unidentified cadavers has increased due to natural disasters and international terrorism. The age estimation is very important for identification of the victims. The degree of sagittal closure is one of such age estimation methods. However it is not widely accepted as a reliable method for age estimation. In this study, we have examined whether measuring impedance value (z-values) of the sagittal suture of the skull is related to the age in men and women and discussed the possibility to use bone impedance for age estimation. Bone impedance values increased with aging and decreased after the age of 64.5. Then we compared age estimation through the conventional visual method and the proposed bone impedance measurement technique. It is suggested that the bone impedance measuring technique may be of value to forensic science as a method of age estimation.

  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. 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.

  6. Aging and Rejuvenation with Fractional Derivatives

    DTIC Science & Technology

    2007-11-02

    Science, University of North Texas, P. O. Box 311427, Denton, Texas 76203-1427, USA 2Dipartimento di Fisica dell’Università di Pisa and INFM, via...interval 2,m,3, yield a generalized master equation equivalent to the sum of an ordinary Markov contribution and a fractional derivative term. We show...though these processes are associated with quite different physical phenomena [14]. His general argu- ments rested on three assumptions: (1) microscopic

  7. 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.

  8. Age estimation based on aspartic acid racemization in human sclera.

    PubMed

    Klumb, Karolin; Matzenauer, Christian; Reckert, Alexandra; Lehmann, Klaus; Ritz-Timme, Stefanie

    2016-01-01

    Age estimation based on racemization of aspartic acid residues (AAR) in permanent proteins has been established in forensic medicine for years. While dentine is the tissue of choice for this molecular method of age estimation, teeth are not always available which leads to the need to identify other suitable tissues. We examined the suitability of total tissue samples of human sclera for the estimation of age at death. Sixty-five samples of scleral tissue were analyzed. The samples were hydrolyzed and after derivatization, the extent of aspartic acid racemization was determined by gas chromatography. The degree of AAR increased with age. In samples from younger individuals, the correlation of age and D-aspartic acid content was closer than in samples from older individuals. The age-dependent racemization in total tissue samples proves that permanent or at least long-living proteins are present in scleral tissue. The correlation of AAR in human sclera and age at death is close enough to serve as basis for age estimation. However, the precision of age estimation by this method is lower than that of age estimation based on the analysis of dentine which is due to molecular inhomogeneities of total tissue samples of sclera. Nevertheless, the approach may serve as a valuable alternative or addition in exceptional cases.

  9. 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.

  10. 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.

  11. HGPS-derived iPSCs for the ages.

    PubMed

    Misteli, Tom

    2011-01-07

    In this issue of Cell Stem Cell, Zhang et al. (2011) generate patient-derived iPSCs for one of the major premature aging diseases, Hutchinson-Gilford Progeria Syndrome (HGPS). These cells are a much-needed new tool to study HGPS, and their use may lead to novel insights into mechanisms of aging.

  12. Estimating age: college males versus convicted male child sex offenders.

    PubMed

    Marsh, Robert; Romero, Sergio; Patrick, Steven

    2013-01-01

    Two samples, male college students and convicted male child sex offenders, are compared on their abilities to accurately estimate the age group of a series of photographs of a sole female ranging in age from 11 to 29. Both samples tend to overestimate the age group of the subject photos, and no significant difference was found between college students and convicted child sex offenders in their ability to estimate the age of females. Both groups are compared demographically, and only limited differences were found. The implications are discussed in regard to theory and prevention of child sexual abuse.

  13. 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…

  14. 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.

  15. 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.

  16. Precision of age estimates from different ageing structures in selected freshwater teleosts.

    PubMed

    Khan, Shahista; Khan, M Afzal; Miyan, Kaish; Lone, Faisal Ahmad

    2015-03-01

    The present study was undertaken with a view to compare the precision of age readings obtained from different ageing structures of some important freshwater teleosts viz., Hypophthalmichthys molitrix, Mastacembelus armatus and Ompok pabda. Standard procedures were followed to study the ageing structures. Based on the highest percent agreement and lowest average percentage of error and coefficient of variation values, precise age estimates were exhibited by opercular bones in H. molitrix and vertebrae in the remaining two fish, M. armatus and O. pabda. When precise age estimates were compared among the age estimates of other ageing structures, highest percent agreement and lowest average percent error and coefficient of variation values were exhibited by vertebrae (versus opercular bones) in H. molitrix and opercular bones (versus vertebrae) in both M. armatus and O. pabda. When mean age estimates from different ageing structures were compared, vertebrae and opercular bones exhibited comparable values in H. molitrix. In M. armatus, mean values of precise age estimates from vertebrae were significantly different from the values of other ageing structures. However, in O. pabda, vertebrae as well as opercular bones showed insignificantly different age readings.

  17. Cells derived from young bone marrow alleviate renal aging.

    PubMed

    Yang, Hai-Chun; Rossini, Michele; Ma, Li-Jun; Zuo, Yiqin; Ma, Ji; Fogo, Agnes B

    2011-11-01

    Bone marrow-derived stem cells may modulate renal injury, but the effects may depend on the age of the stem cells. Here we investigated whether bone marrow from young mice attenuates renal aging in old mice. We radiated female 12-mo-old 129SvJ mice and reconstituted them with bone marrow cells (BMC) from either 8-wk-old (young-to-old) or 12-mo-old (old-to-old) male mice. Transfer of young BMC resulted in markedly decreased deposition of collagen IV in the mesangium and less β-galactosidase staining, an indicator of cell senescence. These changes paralleled reduced expression of plasminogen activator inhibitor-1 (PAI-1), PDGF-B (PDGF-B), the transdifferentiation marker fibroblast-specific protein-1 (FSP-1), and senescence-associated p16 and p21. Tubulointerstitial and glomerular cells derived from the transplanted BMC did not show β-galactosidase activity, but after 6 mo, there were more FSP-1-expressing bone marrow-derived cells in old-to-old mice compared with young-to-old mice. Young-to-old mice also exhibited higher expression of the anti-aging gene Klotho and less phosphorylation of IGF-1 receptor β. Taken together, these data suggest that young bone marrow-derived cells can alleviate renal aging in old mice. Direct parenchymal reconstitution by stem cells, paracrine effects from adjacent cells, and circulating anti-aging molecules may mediate the aging of the kidney.

  18. Estimates of a hedonic ageing equation for partner search.

    PubMed

    Cameron, S; Collins, A

    1997-01-01

    "This paper presents the first attempts by economists to estimate an equation of the demand curve for sexual relationship partner attributes. The focus is on the age of partner sought as the item demanded. A sample of newspaper ¿personal ads' is used to construct the demand curve. The estimates show clear evidence of age trade offs in partner search which vary by gender. There is evidence that financially constrained men will trade down in terms of market desirability, i.e., up in partner age, but also that women will offer to buy younger partners with financial signalling." (EXCERPT)

  19. Estimation of Stratospheric Age Spectrum from Chemical Tracers

    NASA Technical Reports Server (NTRS)

    Schoeberl, Mark R.; Douglass, Anne R.; Polansky, Brian

    2005-01-01

    We have developed a technique to diagnose the stratospheric age spectrum and estimate the mean age of air using the distributions of at least four constituents with different photochemical lifetimes. We demonstrate that the technique works using a 3D CTM and then apply the technique to UMS CLAES January 1993 observations of CFC11, CFC12, CH4 and N2O. Our results are generally in agreement with mean age of air estimates from the chemical model and from observations of SF6 and CO2; however, the mean age estimates show an intrusion of very young tropical air into the mid-latitude stratosphere. This feature is consistent with mixing of high N20 air out of the tropics during the westerly phase of the QBO.

  20. Deductive derivation and turing-computerization of semiparametric efficient estimation.

    PubMed

    Frangakis, Constantine E; Qian, Tianchen; Wu, Zhenke; Diaz, Ivan

    2015-12-01

    Researchers often seek robust inference for a parameter through semiparametric estimation. Efficient semiparametric estimation currently requires theoretical derivation of the efficient influence function (EIF), which can be a challenging and time-consuming task. If this task can be computerized, it can save dramatic human effort, which can be transferred, for example, to the design of new studies. Although the EIF is, in principle, a derivative, simple numerical differentiation to calculate the EIF by a computer masks the EIF's functional dependence on the parameter of interest. For this reason, the standard approach to obtaining the EIF relies on the theoretical construction of the space of scores under all possible parametric submodels. This process currently depends on the correctness of conjectures about these spaces, and the correct verification of such conjectures. The correct guessing of such conjectures, though successful in some problems, is a nondeductive process, i.e., is not guaranteed to succeed (e.g., is not computerizable), and the verification of conjectures is generally susceptible to mistakes. We propose a method that can deductively produce semiparametric locally efficient estimators. The proposed method is computerizable, meaning that it does not need either conjecturing, or otherwise theoretically deriving the functional form of the EIF, and is guaranteed to produce the desired estimates even for complex parameters. The method is demonstrated through an example.

  1. Forensic age estimation of living individuals: a retrospective analysis.

    PubMed

    Santoro, Valeria; De Donno, Antonio; Marrone, Maricla; Campobasso, Carlo Pietro; Introna, Francesco

    2009-12-15

    In recent years, skeletal age determination has become increasingly important in criminal investigations for determining the age of living individuals. To increase diagnostic accuracy, a physical examination, an X-ray examination of the left hand, as well as a dental examination including the determination of the dental status and an X-ray of the dentition should always be performed. In this work, the authors analyze a sample of 52 illegal immigrants who came under their observation in the period from May 1989 to September 2007. A statistical analysis of the results of dental and skeletal age estimations was performed as well as an analysis between the reported and assessed ages. The results showed a significant difference between reported age and assessed biological age (p<0.001); however, no statistical difference was shown between skeletal and assessed dental age (p=0.431).

  2. 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.

  3. Age estimation for forensic purposes in Italy: ethical issues.

    PubMed

    Focardi, Martina; Pinchi, Vilma; De Luca, Federica; Norelli, Gian-Aristide

    2014-05-01

    Age assessment in children and young adults is a relevant medicolegal issue due to the gradual increase of persons devoid of proper identification documents in European countries. Because of the illegal immigration and growing crime rates among children and adolescents, age estimation for forensic purposes is often required. The scientific research and the extensive experience of forensic experts in the last decades focused on the use of radiographic methods addressed to evaluate the degree of skeletal or dental development as the most accurate parameters to estimate the chronological age of children and adolescents. This paper analyzes the ethical issues related to age estimation procedures based on radiographic methods, showing how the ethical principles of beneficence, nonmalevolence, justice, and autonomy may be guaranteed during the execution of the age assessment in forensic practice. The procedure might be conducted in accordance with international guidelines and protocols, though they need a higher homogenization and standardization. A strong collaboration between various scientific societies of professionals (forensic odontologists, forensic pathologists, forensic anthropologist, radiologists, pediatricians, and psychologists), who have been involved in age estimation for years, is needed to reach this goal.

  4. 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.

  5. 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

  6. 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.

  7. Tip vortex core pressure estimates derived from velocity field measurements

    NASA Astrophysics Data System (ADS)

    Sinding, Kyle; Krane, Michael

    2016-11-01

    We present estimates of tip vortex core pressure derived from velocity field measurements of a high Reynolds number flow over a lifting surface. Tip vortex cavitation decreases propulsor efficiency and contributes to both unwanted noise and surface damage. Coordinated load cell, pressure, and velocity measurements were performed in the 12-inch tunnel at the Applied Research Laboratory at Penn State University, over a range of angles of attack and flow speeds. Stereo PIV imaging planes were oriented normal to the tunnel axis. Pressure estimates in each measurement plane were estimated from the velocity field. Visual cavitation calls were performed over the same range of conditions as the optical velocity measurements, by varying the tunnel pressure until tip vortex cavitation was observed to initiate. The pressure differences between the tip vortex and the tunnel ambient pressure obtained with these two methods were then compared.

  8. Age estimation of unidentified corpses by measurement of root translucency.

    PubMed

    Olze, A; Geserick, G; Schmeling, A

    2004-12-01

    To evaluate the root dentine translucency technique for age analysis, age estimates carried out at the Institute of Legal Medicine at the Charité University Hospital in Berlin between 1998 and 2002 of unidentified corpses were subjected to retrospective review. Teeth suitable for evaluation were obtained from 33 corpses of undisputed identity. Root translucency was measured at intervals of half a millimetre. Appropriate reference studies were used to translate the measurements obtained into estimated age. In 18 cases these estimates proved correct. In 14 cases the deviation lay within +/-10 years. In one case of known drug abuse combined with diabetic metabolism, two factors which promote the advance of root translucency, the deviation was 12 years. It was concluded that the described technique, which requires little time and money and is easy to apply, can produce sound results in the middle age group (30-60). To avoid seriously inaccurate estimates in individual cases, the result should always be verified critically against an assessment of the overall stomatognathic system and other post-mortem findings of relevance to age.

  9. 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.

  10. 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.

  11. 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

  12. Age estimation from dental cementum incremental lines and periodontal disease.

    PubMed

    Dias, P E M; Beaini, T L; Melani, R F H

    2010-12-01

    Age estimation by counting incremental lines in cementum added to the average age of tooth eruption is considered an accurate method by some authors, while others reject it stating weak correlation between estimated and actual age. The aim of this study was to evaluate this technique and check the influence of periodontal disease on age estimates by analyzing both the number of cementum lines and the correlation between cementum thickness and actual age on freshly extracted teeth. Thirty one undecalcified ground cross sections of approximately 30 µm, from 25 teeth were prepared, observed, photographed and measured. Images were enhanced by software and counts were made by one observer, and the results compared with two control-observers. There was moderate correlation ((r)=0.58) for the entire sample, with mean error of 9.7 years. For teeth with periodontal pathologies, correlation was 0.03 with a mean error of 22.6 years. For teeth without periodontal pathologies, correlation was 0.74 with mean error of 1.6 years. There was correlation of 0.69 between cementum thickness and known age for the entire sample, 0.25 for teeth with periodontal problems and 0.75 for teeth without periodontal pathologies. The technique was reliable for periodontally sound teeth, but not for periodontally diseased teeth.

  13. Data-Dependent Label Distribution Learning for Age Estimation.

    PubMed

    He, Zhouzhou; Li, Xi; Zhang, Zhongfei; Wu, Fei; Geng, Xin; Zhang, Yaqing; Yang, Ming-Hsuan; Zhuang, Yueting

    2017-01-18

    As an important and challenging problem in computer vision, face age estimation is typically cast as a classification or regression problem over a set of face samples with respect to several ordinal age labels, which have intrinsically cross-age correlations across adjacent age dimensions. As a result, such correlations usually lead to the age label ambiguities of the face samples. Namely, each face sample is associated with a latent label distribution that encodes the cross-age correlation information on label ambiguities. Motivated by this observation, we propose a totally data-driven label distribution learning approach to adaptively learn the latent label distributions. The proposed approach is capable of effectively discovering the intrinsic age distribution patterns for cross-age correlation analysis on the basis of the local context structures of face samples. Without any prior assumptions on the forms of label distribution learning, our approach is able to flexibly model the sample-specific context aware label distribution properties by solving a multi-task problem, which jointly optimizes the tasks of age-label distribution learning and age prediction for individuals. Experimental results demonstrate the effectiveness of our approach.

  14. 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.

  15. 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.

  16. Improving size estimates of open animal populations by incorporating information on age

    USGS Publications Warehouse

    Manly, Bryan F.J.; McDonald, Trent L.; Amstrup, Steven C.; Regehr, Eric V.

    2003-01-01

    Around the world, a great deal of effort is expended each year to estimate the sizes of wild animal populations. Unfortunately, population size has proven to be one of the most intractable parameters to estimate. The capture-recapture estimation models most commonly used (of the Jolly-Seber type) are complicated and require numerous, sometimes questionable, assumptions. The derived estimates usually have large variances and lack consistency over time. In capture–recapture studies of long-lived animals, the ages of captured animals can often be determined with great accuracy and relative ease. We show how to incorporate age information into size estimates for open populations, where the size changes through births, deaths, immigration, and emigration. The proposed method allows more precise estimates of population size than the usual models, and it can provide these estimates from two sample occasions rather than the three usually required. Moreover, this method does not require specialized programs for capture-recapture data; researchers can derive their estimates using the logistic regression module in any standard statistical package.

  17. Age estimation using level of eyebrow and eyelash whitening

    PubMed Central

    Kantarcı, Feride Aylin; Kantarcı, Muhammed Nabi; Bilgi, Sefer

    2014-01-01

    Background The aim of this study was to determine whether eyebrow and eyelash whitening is an effective parameter in age estimation. Material/Methods We evaluated 1545 patients. Age groups were 1–10, 11–20, 21–30, 31–40, 41–50, 51–60, 61–70, 71–80, and 81–90 years. Level of whitening was categorized as level 0: no whitening, level 1: 1–3 strands, level 2: 3–10 strands, level 3: 10 strands–2/3 whitening, level 4: >3/4 whitening. Results Mean age was 42.39±20.01. While there was no eyebrow whitening in 87% of the subjects, level 4 whitening of eyebrows was observed in 0,8% of the subjects. There was no eyelash whitening in 97,7% of the subjects and no level 4 eyelash whitening was detected in any subject. Men had significantly more level 1, 2, 3, and 4 eyebrow whitening compared with women. There was no gender difference in terms of eyelash whitening level. There was no eyebrow and eyelash whitening in subjects age 1–40 years; whitening began in the 41–50 years age group and increased with age in other groups. Mean age was 39.59±19.63 years in subjects with no eyebrow whitening; 59 years in level 1, 61 years in level 2, 63 years in level 3, and 69 years in level 4 eyebrow whitening. Mean age was 41.85±19.87 in subjects with no eyelash whitening; and 63.57±10.75 in those with whitening. Conclusions Particularly after 41–50 years of age, level of eyebrow and eyelash whitening may be among a useful age estimation parameter. PMID:24448310

  18. The frailty index outperforms DNA methylation age and its derivatives as an indicator of biological age.

    PubMed

    Kim, Sangkyu; Myers, Leann; Wyckoff, Jennifer; Cherry, Katie E; Jazwinski, S Michal

    2017-02-01

    The measurement of biological age as opposed to chronological age is important to allow the study of factors that are responsible for the heterogeneity in the decline in health and function ability among individuals during aging. Various measures of biological aging have been proposed. Frailty indices based on health deficits in diverse body systems have been well studied, and we have documented the use of a frailty index (FI34) composed of 34 health items, for measuring biological age. A different approach is based on leukocyte DNA methylation. It has been termed DNA methylation age, and derivatives of this metric called age acceleration difference and age acceleration residual have also been employed. Any useful measure of biological age must predict survival better than chronological age does. Meta-analyses indicate that age acceleration difference and age acceleration residual are significant predictors of mortality, qualifying them as indicators of biological age. In this article, we compared the measures based on DNA methylation with FI34. Using a well-studied cohort, we assessed the efficiency of these measures side by side in predicting mortality. In the presence of chronological age as a covariate, FI34 was a significant predictor of mortality, whereas none of the DNA methylation age-based metrics were. The outperformance of FI34 over DNA methylation age measures was apparent when FI34 and each of the DNA methylation age measures were used together as explanatory variables, along with chronological age: FI34 remained significant but the DNA methylation measures did not. These results indicate that FI34 is a robust predictor of biological age, while these DNA methylation measures are largely a statistical reflection of the passage of chronological time.

  19. 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.

  20. Non-parametric estimation of age-related centiles over wide age ranges.

    PubMed

    Pan, H Q; Goldstein, H; Yang, Q

    1990-01-01

    A new method for estimating age-related centile curves has been developed, which is suitable for measurement covering a wide age range. The method was used to calculate weight centile curves of 8995 children from birth to 6 years obtained by the Collaborating Centre for Physical Growth and Psychosocial Development of Children in Shanghai, China.

  1. 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

  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. 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

  4. Demirjian approach of dental age estimation: Abridged for operator ease

    PubMed Central

    Jain, Vanshika; Kapoor, Priyanka; Miglani, Ragini

    2016-01-01

    Background: Present times have seen an alarming increase in incidence of crimes by juveniles and of mass destruction that Highlight the preponderance of individual age estimation. Of the numerous techniques employed for age assessment, dental age estimation (DAE) and its correlation with chronological age (CA) have been of great significance in the recent past. Demirjian system, considered as gold standard in DAE is a simple and convenient method for DAE, though,, although, referring to multiple tables make it cumbersome and less eco friendly due to excessive paper load. Aim: The present study was aimed to develop a comprehensive chart (DAEcc) inclusive of all Demirjian tables and developmental stages of teeth and also to as well as to test the operator ease of 50 undergraduate dental students in performing DAE using this chart. Materials and Methods: The study was performed in two stages, wherein the first stage was aimed at formulation of the comprehensive chart (DAECC) which included pictorial representation of calcification stages, the Federation Dentaire Internationale notation of the teeth, and the corresponding scores for each stage with a concluding column at the end to enter the total score. The second stage assessed the applicability of the ease of DAE by DAECC, whereby fifty 2nd year BDS students were asked to trace the calcification stages of the seven permanent left mandibular teeth on a panorex, identify the correct stage, assign the corresponding score, and to calculate the total score for subsequent dental age assessment. Results and Conclusions: showed that average time taken by the students for tracing seven mandibular teeth was 5 min and for assessment of dental age was 7 min. The total time taken for DAE was approximately 12 min, thus making the procedure less time consuming. Hence, this study proposes the use of DAEcc for age estimation due to ease in comprehension and execution of Demirjian system. PMID:28123280

  5. 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. ;

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Psychophysical estimation of speed discrimination. II. Aging effects

    NASA Astrophysics Data System (ADS)

    Raghuram, Aparna; Lakshminarayanan, Vasudevan; Khanna, Ritu

    2005-10-01

    We studied the effects of aging on a speed discrimination task using a pair of first-order drifting luminance gratings. Two reference speeds of 2 and 8 deg/s were presented at stimulus durations of 500 ms and 1000 ms. The choice of stimulus parameters, etc., was determined in preliminary experiments and described in Part I. Thresholds were estimated using a two-alternative-forced-choice staircase methodology. Data were collected from 16 younger subjects (mean age 24 years) and 17 older subjects (mean age 71 years). Results showed that thresholds for speed discrimination were higher for the older age group. This was especially true at stimulus duration of 500 ms for both slower and faster speeds. This could be attributed to differences in temporal integration of speed with age. Visual acuity and contrast sensitivity were not statistically observed to mediate age differences in the speed discrimination thresholds. Gender differences were observed in the older age group, with older women having higher thresholds.

  11. Psychophysical estimation of speed discrimination. II. Aging effects.

    PubMed

    Raghuram, Aparna; Lakshminarayanan, Vasudevan; Khanna, Ritu

    2005-10-01

    We studied the effects of aging on a speed discrimination task using a pair of first-order drifting luminance gratings. Two reference speeds of 2 and 8 deg/s were presented at stimulus durations of 500 ms and 1000 ms. The choice of stimulus parameters, etc., was determined in preliminary experiments and described in Part I. Thresholds were estimated using a two-alternative-forced-choice staircase methodology. Data were collected from 16 younger subjects (mean age 24 years) and 17 older subjects (mean age 71 years). Results showed that thresholds for speed discrimination were higher for the older age group. This was especially true at stimulus duration of 500 ms for both slower and faster speeds. This could be attributed to differences in temporal integration of speed with age. Visual acuity and contrast sensitivity were not statistically observed to mediate age differences in the speed discrimination thresholds. Gender differences were observed in the older age group, with older women having higher thresholds.

  12. 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

  13. Estimation of dynamic functional connectivity using Multiplication of Temporal Derivatives.

    PubMed

    Shine, James M; Koyejo, Oluwasanmi; Bell, Peter T; Gorgolewski, Krzysztof J; Gilat, Moran; Poldrack, Russell A

    2015-11-15

    Functional connectivity provides an informative and powerful framework for exploring brain organization. Despite this, few statistical methods are available for the accurate estimation of dynamic changes in functional network architecture. To date, the majority of existing statistical techniques have assumed that connectivity structure is stationary, which is in direct contrast to emerging data that suggests that the strength of connectivity between regions is variable over time. Therefore, the development of statistical methods that enable exploration of dynamic changes in functional connectivity is currently of great importance to the neuroscience community. In this paper, we introduce the 'Multiplication of Temporal Derivatives' (MTD) and then demonstrate the utility of this metric to: (i) detect dynamic changes in connectivity using data from a novel state-switching simulation; (ii) accurately estimate graph structure in a previously-described 'ground-truth' simulated dataset; and (iii) identify task-driven alterations in functional connectivity. We show that the MTD is more sensitive than existing sliding-window methods in detecting dynamic alterations in connectivity structure across a range of correlation strengths and window lengths in simulated data. In addition to the temporal precision offered by MTD, we demonstrate that the metric is also able to accurately estimate stationary network structure in both simulated and real task-based data, suggesting that the method may be used to identify dynamic changes in network structure as they evolve through time.

  14. Similarity estimators for irregular and age-uncertain time series

    NASA Astrophysics Data System (ADS)

    Rehfeld, K.; Kurths, J.

    2014-01-01

    Paleoclimate time series are often irregularly sampled and age uncertain, which is an important technical challenge to overcome for successful reconstruction of past climate variability and dynamics. Visual comparison and interpolation-based linear correlation approaches have been used to infer dependencies from such proxy time series. While the first is subjective, not measurable and not suitable for the comparison of many data sets at a time, the latter introduces interpolation bias, and both face difficulties if the underlying dependencies are nonlinear. In this paper we investigate similarity estimators that could be suitable for the quantitative investigation of dependencies in irregular and age-uncertain time series. We compare the Gaussian-kernel-based cross-correlation (gXCF, Rehfeld et al., 2011) and mutual information (gMI, Rehfeld et al., 2013) against their interpolation-based counterparts and the new event synchronization function (ESF). We test the efficiency of the methods in estimating coupling strength and coupling lag numerically, using ensembles of synthetic stalagmites with short, autocorrelated, linear and nonlinearly coupled proxy time series, and in the application to real stalagmite time series. In the linear test case, coupling strength increases are identified consistently for all estimators, while in the nonlinear test case the correlation-based approaches fail. The lag at which the time series are coupled is identified correctly as the maximum of the similarity functions in around 60-55% (in the linear case) to 53-42% (for the nonlinear processes) of the cases when the dating of the synthetic stalagmite is perfectly precise. If the age uncertainty increases beyond 5% of the time series length, however, the true coupling lag is not identified more often than the others for which the similarity function was estimated. Age uncertainty contributes up to half of the uncertainty in the similarity estimation process. Time series irregularity

  15. Similarity estimators for irregular and age uncertain time series

    NASA Astrophysics Data System (ADS)

    Rehfeld, K.; Kurths, J.

    2013-09-01

    Paleoclimate time series are often irregularly sampled and age uncertain, which is an important technical challenge to overcome for successful reconstruction of past climate variability and dynamics. Visual comparison and interpolation-based linear correlation approaches have been used to infer dependencies from such proxy time series. While the first is subjective, not measurable and not suitable for the comparison of many datasets at a time, the latter introduces interpolation bias, and both face difficulties if the underlying dependencies are nonlinear. In this paper we investigate similarity estimators that could be suitable for the quantitative investigation of dependencies in irregular and age uncertain time series. We compare the Gaussian-kernel based cross correlation (gXCF, Rehfeld et al., 2011) and mutual information (gMI, Rehfeld et al., 2013) against their interpolation-based counterparts and the new event synchronization function (ESF). We test the efficiency of the methods in estimating coupling strength and coupling lag numerically, using ensembles of synthetic stalagmites with short, autocorrelated, linear and nonlinearly coupled proxy time series, and in the application to real stalagmite time series. In the linear test case coupling strength increases are identified consistently for all estimators, while in the nonlinear test case the correlation-based approaches fail. The lag at which the time series are coupled is identified correctly as the maximum of the similarity functions in around 60-55% (in the linear case) to 53-42% (for the nonlinear processes) of the cases when the dating of the synthetic stalagmite is perfectly precise. If the age uncertainty increases beyond 5% of the time series length, however, the true coupling lag is not identified more often than the others for which the similarity function was estimated. Age uncertainty contributes up to half of the uncertainty in the similarity estimation process. Time series irregularity

  16. 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.

  17. [Observation of cervical vertebrae and estimation of their bone age].

    PubMed

    Zhang, Y; Wang, B

    1997-05-01

    There are two objectives in this study: the first is to estimate skeletal age by lateral cephalomatric roentgengram of cervical vertebrae instead of X-ray of handwrist, the second is to study the rules of cervical vertebrae's growth and development of children from Beijing. The Auto CAD 12.0 computer software was used in measuring lateral cephalomatric roentgengrams of cervical vertebrae of 280 children from Beijing aged 9-15. The shape of cervical vertebrae of children with that of adults on X-ray films was compared, and the growth and development of cervical vertebrae of 9-15 years old children from Beijing was observed. We found out that the rapid growth period of cervical vertebrae was 12-14 years old for girls and 14-15 years old for boys. During puberty, the change of vertebrae's shape has no difference between male and female. 42 female and 28 male teenagers from the 280 aged 9-13 years old were taken X-ray films of left handwrist. The comparison between the films and roentgengrams shows that the appearance of sesamoid of hand and the concavity of the second vertebrae body is at the same time, which means that the beginning of rapid growth period can be estimated by the lateral cephalometric roentgengrams of cervical vertebrae.

  18. 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

  19. Phase derivative estimation from a single interferogram using a Kalman smoothing algorithm.

    PubMed

    Kulkarni, Rishikesh; Rastogi, Pramod

    2015-08-15

    We report a technique for direct phase derivative estimation from a single recording of a complex interferogram. In this technique, the interference field is represented as an autoregressive model with spatially varying coefficients. Estimates of these coefficients are obtained using the Kalman filter implementation. The Rauch-Tung-Striebel smoothing algorithm further improves the accuracy of the coefficient estimation. These estimated coefficients are utilized to compute the spatially varying phase derivative. Stochastic evolution of the coefficients is considered, which allows estimating the phase derivative with any type of spatial variation. The simulation and experimental results are provided to substantiate the noise robustness and applicability of the proposed method in phase derivative estimation.

  20. Derivation of site-specific skeletal masses within the current ICRP age series.

    PubMed

    Watchman, Christopher J; Hasenauer, Deanna; Bolch, Wesley E

    2007-06-07

    The calculation of absorbed dose to the radiosensitive tissues of the skeleton is routinely performed using reference masses provided in publications from the International Commission on Radiological Protection (ICRP). These values typically include total skeleton tissue masses by reference subject age, but not by individual bone site at a given age. Site-specific variations in absorbed fractions are known to occur for internal alpha-particle and beta-particle emitters, and in certain medical dose reconstructions, site-specific estimates of marrow dose may be desirable. Furthermore, bone-site-specific tissue masses are required to properly estimate skeletal-averaged absorbed fractions and, more importantly, specific absorbed fractions for internalized radionuclides and radiopharmaceuticals. Reference masses by skeletal site are also needed in the development of ICRP compliant tomographic phantoms, as this organ system is initially segmented from medical images only as a homogeneous tissue region. ICRP reference skeletal masses are assigned based upon several independent data sources, many of which may not be entirely consistent with one another. In this study, a methodology is presented, using data from the various ICRP publications, to derive site-specific skeletal tissue masses for each member of the ICRP age series. Active marrow masses are calculated and differences are shown with respect to ICRP Publications 70 and 89 values. New data for a revised surrogate tissue region for the osteoprogenitor cells within bone marrow is presented with estimates of its total mass throughout the skeleton and for different subject ages.

  1. Estimation of spaceplane longitudinal stability and control derivatives from dynamic wind tunnel test

    NASA Astrophysics Data System (ADS)

    Yanagihara, Masaaki; Sasa, Shuichi; Shimomura, Takashi; Takizawa, Minoru; Suzuki, Seizo; Nagayasu, Masahiko

    Dynamic wind tunnel tests using a 5-percent cable-mounted model of the NAL spaceplane have been conducted in the NAL low-speed large scale wind tunnel. A parameter identification study of the recorded data was undertaken to extract longitudinal stability and control derivatives. The following three estimation methods were adopted: (1) estimate all the derivatives simultaneously; (2) estimate the stability and control derivatives separately; and (3) estimate the dynamic derivatives only while the static derivatives are fixed in results from static wind tunnel tests. The estimated derivatives were evaluated by comparing mathematically simulated time histories based on them with tunnel test data. As a result, all major derivatives were estimated well and the effectiveness of the dynamic test was shown.

  2. 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.

  3. 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.

  4. Why Was Kelvin's Estimate of the Earth's Age Wrong?

    NASA Astrophysics Data System (ADS)

    Lovatt, Ian; Syed, M. Qasim

    2014-05-01

    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 wrong not because he did not account for radioactivity, as is commonly believed,4 but because he used the wrong model for Earth's heat loss. We feel this idea is worth spreading. To this end (following England et al.), we examine two questions, the first about the radioactivity part and the second about Perry's alternate model for Earth's heat loss.

  5. 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.

  6. 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... age population estimates as of July 1, 2009, for each state and the District of Columbia. We are..., United States Code, Section 441a(e), I hereby give notice that the estimates of the voting age...

  7. 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... voting age population estimates as of July 1, 2012, for each state and the District of Columbia. We are..., United States Code, Section 441a(e), I hereby give notice that the estimates of the voting age...

  8. 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... age population estimates as of July 1, 2010, for each state and the District of Columbia. We are...), I hereby give notice that the estimates of the voting age population for July 1, 2010, for...

  9. 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... age population estimates as of July 1, 2011, for each state and the District of Columbia. We are..., United States Code, Section 441a(e), I hereby give notice that the estimates of the voting age...

  10. Assay of methylglyoxal-derived protein and nucleotide AGEs.

    PubMed

    Rabbani, Naila; Shaheen, Fozia; Anwar, Attia; Masania, Jinit; Thornalley, Paul J

    2014-04-01

    Glyoxalase- and methylglyoxal-related research has required the development of quantitative and reliable techniques for the measurement of methylglyoxal-derived glycation adducts of protein and DNA. There are also other glycation adducts, oxidation adducts and nitration adducts of proteins and oxidation adducts of DNA. Proteolysis of protein releases glycation, oxidation and nitration free adducts (glycated, oxidized and nitrated amino acids) in plasma and nuclease digestion of DNA releases glycated and oxidized nucleosides into plasma and other body fluids for excretion in urine. The gold standard method for quantifying these adducts is stable isotopic dilution analysis LC-MS/MS. Protein and DNA adduct residues are determined by assay of enzymatic hydrolysates of protein and DNA extracts prepared using cocktails of proteases and nucleases respectively. Free adducts are determined by analysis of ultrafiltrates of plasma, urine and other physiological fluids. Protein damage markers (13 glycation adducts, five oxidation adducts and 3-nitrotyrosine) and DNA damage markers (three glycation adducts and one oxidation adduct) are quantified using 25 μg of protein, 10 μg of DNA or 5 μl of physiological fluid. Protein and nucleotide AGE (advanced glycation end-product) assay protocols resistant to interferences is described.

  11. Estimated Pulse Wave Velocity Calculated from Age and Mean Arterial Blood Pressure

    PubMed Central

    Greve, Sara V.; Laurent, Stephan; Olsen, Michael H.

    2017-01-01

    In a recently published paper, Greve et al [J Hypertens 2016;34:1279-1289] investigate whether the estimated carotid-femoral pulse wave velocity (ePWV), calculated using an equation derived from the relationship between carotid-femoral pulse wave velocity (cfPWV), age, and blood pressure, predicts cardiovascular disease (CVD) as good as the measured cfPWV. Because ePWV predicts CVD as good as cfPWV, some might wonder whether ePWV could be replaced by cfPWV, which is a time-consuming measurement requiring an expensive apparatus. This question is addressed in this mini-review. PMID:28229052

  12. 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

  13. 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...

  14. Consistent thermodynamic derivative estimates for tabular equations of state.

    PubMed

    Dilts, Gary A

    2006-06-01

    A valid fluid equation of state (EOS) must satisfy the thermodynamic conditions of consistency (derivation from a free energy) and stability (positive sound speed squared). Numerical simulations of compressible fluid flow for realistic materials require a tabular EOS, but typical software interfaces to such tables based on polynomial or rational interpolants may enforce the stability conditions, but do not enforce the consistency condition and its derivatives. The consistency condition is important for the computation of various dimensionless parameters of an EOS that may involve derivatives of up to second order which are important for the development of more sensitive artificial viscosities and Riemann solvers that accurately model shock structure in regions near phase transitions. We describe a table interface based on the tuned regression method, which is derived from a constrained local least-squares regression technique. It is applied to several SESAME EOS showing how the consistency and stability conditions can be satisfied to round-off while computing first and second derivatives with demonstrated second-order convergence. An improvement of 14 orders of magnitude over conventional derivatives is demonstrated, although the method is apparently two orders of magnitude slower, due to the fact that every evaluation requires solving an 11-dimensional nonlinear system. Application is made to the computation of the fundamental derivative.

  15. Consistent thermodynamic derivative estimates for tabular equations of state

    NASA Astrophysics Data System (ADS)

    Dilts, Gary A.

    2006-06-01

    A valid fluid equation of state (EOS) must satisfy the thermodynamic conditions of consistency (derivation from a free energy) and stability (positive sound speed squared). Numerical simulations of compressible fluid flow for realistic materials require a tabular EOS, but typical software interfaces to such tables based on polynomial or rational interpolants may enforce the stability conditions, but do not enforce the consistency condition and its derivatives. The consistency condition is important for the computation of various dimensionless parameters of an EOS that may involve derivatives of up to second order which are important for the development of more sensitive artificial viscosities and Riemann solvers that accurately model shock structure in regions near phase transitions. We describe a table interface based on the tuned regression method, which is derived from a constrained local least-squares regression technique. It is applied to several SESAME EOS showing how the consistency and stability conditions can be satisfied to round-off while computing first and second derivatives with demonstrated second-order convergence. An improvement of 14 orders of magnitude over conventional derivatives is demonstrated, although the method is apparently two orders of magnitude slower, due to the fact that every evaluation requires solving an 11-dimensional nonlinear system. Application is made to the computation of the fundamental derivative.

  16. 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.

  17. AN ALGORITHM FOR THE ESTIMATION OF GESTATIONAL AGE AT THE TIME OF FETAL DEATH

    PubMed Central

    Conway, Deborah L.; Hansen, Nellie I.; Dudley, Donald J.; Parker, Corette B.; Reddy, Uma M.; Silver, Robert M.; Bukowski, Radek; Pinar, Halit; Stoll, Barbara J.; Varner, Michael W.; Saade, George R.; Hogue, Carol; Willinger, Marian; Coustan, Donald; Koch, Matthew A.; Goldenberg, Robert L.

    2013-01-01

    Background Accurate assignment of gestational age at time of fetal death is important for research and clinical practice. An algorithm to estimate gestational age (GA) at fetal death was developed and evaluated. Methods The algorithm developed by the Stillbirth Collaborative Research Network (SCRN) incorporated clinical and postmortem data. The SCRN conducted a population-based case-control study of women with stillbirths and live births from 2006 to 2008 in five geographic catchment areas. Rules were developed to estimate a due date, identify an interval during which death likely occurred, and estimate GA at the time of fetal death. Reliability of using fetal foot length to estimate GA at death was assessed. Results The due date estimated for 620 singleton stillbirths studied was considered clinically reliable for 87%. Only 25.2% of stillbirths were documented alive within two days before diagnosis and 47.6% within one week of diagnosis. The algorithm-derived estimate of GA at time of fetal death was 1 or more weeks earlier than the GA at delivery for 43.5% of stillbirths. GA estimated from fetal foot length agreed with GA by algorithm within two weeks for 75% within a subset of well-dated stillbirths. Conclusions Precise assignment of GA at death, defined as reliable dating criteria and a short interval (≤1 week) during which fetal death was known to have occurred, was possible in 46.6% of cases. Fetal foot length is a relatively accurate measure of GA at death and should be collected in all stillbirth cases. PMID:23374059

  18. Employing Sensitivity Derivatives to Estimate Uncertainty Propagation in CFD

    NASA Technical Reports Server (NTRS)

    Putko, Michele M.; Newman, Perry A.; Taylor, Arthur C., III

    2004-01-01

    Two methods that exploit the availability of sensitivity derivatives are successfully employed to predict uncertainty propagation through Computational Fluid Dynamics (CFD) code for an inviscid airfoil problem. An approximate statistical second-moment method and a Sensitivity Derivative Enhanced Monte Carlo (SDEMC) method are successfully demonstrated on a two-dimensional problem. First- and second-order sensitivity derivatives of code output with respect to code input are obtained through an efficient incremental iterative approach. Given uncertainties in statistically independent, random, normally distributed flow parameters (input variables); these sensitivity derivatives enable one to formulate first- and second-order Taylor Series approximations for the mean and variance of CFD output quantities. Additionally, incorporation of the first-order sensitivity derivatives into the data reduction phase of a conventional Monte Carlo (MC) simulation allows for improved accuracy in determining the first moment of the CFD output. Both methods are compared to results generated using a conventional MC method. The methods that exploit the availability of sensitivity derivatives are found to be valid when considering small deviations from input mean values.

  19. Consistent thermodynamic derivative estimates for tabular equations of state.

    NASA Astrophysics Data System (ADS)

    Dilts, Gary

    2005-07-01

    A valid fluid equation of state must satisfy the thermodynamic differential conditions of consistency (derivation from a free energy) and stability (positive sound speed squared). Typical software interfaces to tabular equations of state based on polynomial or rational interpolants compute derivatives of pressure and energy and may enforce the stability conditions, but do not enforce the consistency condition and its derivatives, which is important for the computation of dimensionless quantities associated with more sensitive artificial viscosities and Riemann solvers that accurately model shock structure in regions near phase transitions. We describe a new type of table interface derived from a constrained local least squares regression technique. Application to several SESAME tables shows the consistency condition can be satisfied to round-off with third-order accuracy. An improvement of 14 orders of magnitude over conventional derivatives is demonstrated, although the new method is two orders of magnitude slower, due to solving an 11-dimensional nonlinear system. The new approach can be used to construct consistent and stable tables of derivatives, however.

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

    PubMed

    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.

  1. 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

  2. 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.

  3. 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.

  4. 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…

  5. Smooth Nonparametric Estimation of the Failure Rate Function and its First Two Derivatives

    NASA Astrophysics Data System (ADS)

    Koshkin, G. M.

    2016-10-01

    The class of nonparametric estimators of kernel type is considered for the unknown failure rate function and its derivatives. The convergence of the suggested estimations in distribution and in the mean square sense to the unknown failure rate function and its derivatives is proved. The interval estimator of the failure rate function is constructed. Advantages of the nonparametric estimators in comparison with the parametric algorithms are discussed. The suggested estimators of the failure rate function can be used to solve problems of exploitation reliability of complex physical, technical, and software systems under uncertainty conditions.

  6. 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

  7. 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.

  8. [Estimating cardiovascular age of civil flying personnel by means of heart rate and blood pressure variability analysis].

    PubMed

    Niu, Y G; Zhang, L F; Zhang, Y H; Wang, S Y; Xu, X Y; Su, J X; Yan, Y B

    2001-06-01

    Objective. To estimate the cardiovascular age of civil flying personnel by means of heart rate and blood pressure variability analysis and to evaluate its significance in aviation medicine. Method. First, heart rate variability (HRV), blood pressure variability (BPV) and spontaneous baroreflex sensitivity (BRS) were analyzed among 89 healthy civil flying personnel by using conventional AR spectral analysis and sequence method respectively. Then, principal component analysis was conducted over original and derived variables of HRV and BPV spectral and BRS data. Finally, by the use of multiple regression in which the chronological age acted as the dependent variable and the components significantly related to age were used as the regressors, the equation for estimating the cardiovascular age was established. Result. Only seven principal components can exactly reflect the same information of autonomic regulatory function which was embodied in the 17 variables of HRV and BPV spectral and BRS parameters. Among the seven principal components, the PC2orig, PC4orig and PC2deri were negatively correlated with chronological age (P<0.05), whereas the PC3orig was positively correlated with the chronological age (P<0.01). The cardiovascular age derived from the equation was significantly correlated with the chronological age of the civil flying personnel (r= 0.73, P<0.01). Conclusion. The cardiovascular age estimated by means of a multi-variate analysis of HRV, BPV and BRS can be treated as a comprehensive indicator reflecting the age dependency of autonomic regulatory function of cardiovascular system in healthy civil flying personnel, and its interpretation and significance in application are surely worthy of further and fully dedicated efforts.

  9. 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.

  10. 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

  11. [The application of telomere DNA in age estimation of forensic medicine].

    PubMed

    Sun, Hong-wei; Gao, Cai-rong

    2005-05-01

    Estimating tooth age and skeletal age are the two primary methods in age estimation of forensic medicine. But they are often impacted with geographical environment, nutrition, habitation and ethenologic differences, so the accuracy will be reduced, especially to the adult. With the study of telomere, it is certain that the length of the telomere DNA can reflect the cell division and represent the cell lifespan, and it has some pertinence to the age of the donor, so to measure the length of telomere DNA is a new and valuable method for age estimation in the forensic medicine.

  12. 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

  13. Improving lidar-derived turbulence estimates for wind energy

    SciTech Connect

    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 data 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

  14. The effects of racemization rate for age estimation of pink teeth.

    PubMed

    Sakuma, Ayaka; Saitoh, Hisako; Ishii, Namiko; Iwase, Hirotaro

    2015-03-01

    Pink teeth is thought to result from the seepage of hemoglobin caused by dental pulp decomposition. We investigated whether racemization can be applied for age estimation in cases of pink teeth where the whole tooth is used. The pink teeth used were three cases and the normal teeth for control were five mandibular canines of known age. Age of the pink teeth was calculated on the basis of regression formula obtained from the five control teeth. Only a slight error was noted between the actual and estimated ages of the pink teeth (R(2) = 0.980, r = 0.990): Cases 1-3 actually aged 23, 53, and 59 years were estimated to be 26, 52, and 60 years. Based on our results of testing pink teeth of known age, we suggest that racemization techniques allow for the age estimation of pink teeth using the same methods for normally colored teeth.

  15. 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

  16. 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.

  17. Age- and sex-dependent model for estimating radioiodine dose to a normal thyroid

    SciTech Connect

    Killough, G.G.; Eckerman, K.F.

    1985-01-01

    This paper describes the derivation of an age- and sex-dependent model of radioiodine dosimetry in the thyroid and the application of the model to estimating the thyroid dose for each of 4215 patients who were exposed to /sup 131/I in diagnostic and therapeutic procedures. The model was made to conform to these data requirements by the use of age-specific estimates of the biological half-time of iodine in the thyroid and an age- and sex-dependent representation of the mass of the thyroid. Also, it was assumed that the thyroid burden was maximum 24 hours after administration (the /sup 131/I dose is not critically sensitive to this assumption). The metabolic model is of the form A(t) = K(exp(-..mu../sub 1/t) - exp(-..mu../sub 2/t)) (..mu..Ci), where ..mu../sub 1/ = lambda/sub r/ + lambda/sub i//sup b/ (i = 1, 2), lambda/sub r/ is the radiological decay-rate coefficient, and lambda/sub i//sup b/ are biological removal rate coefficients. The values of lambda/sub i//sup b/ are determined by solving a nonlinear equation that depends on assumptions about the time of maximum uptake and the eventual biological loss rate (through which age dependence enters). The value of K may then be calculated from knowledge of the uptake at a particular time. The dosimetric S-factor (rad/..mu..Ci-day) is based on specific absorbed fractions for photons of energy ranging from 0.01 to 4.0 MeV for thyroid masses from 1.29 to 19.6 g; the functional form of the S-factor also involves the thyroid mass explicitly, through which the dependence on age and sex enters. An analysis of sensitivity of the model to uncertainties in the thyroid mass and the biological removal rate for several age groups is reported. The model could prove useful in the dosimetry of very short-lived radioiodines. Tables of age- and sex-dependent coefficients are provided to enable readers to make their own calculations. 12 refs., 5 figs., 4 tabs.

  18. 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

  19. 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%.

  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. 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

  2. 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

  3. 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

  4. Anti-aging effects of vitamin C on human pluripotent stem cell-derived cardiomyocytes.

    PubMed

    Kim, Yoon Young; Ku, Seung-Yup; Huh, Yul; Liu, Hung-Ching; Kim, Seok Hyun; Choi, Young Min; Moon, Shin Yong

    2013-10-01

    Human pluripotent stem cells (hPSCs) have arisen as a source of cells for biomedical research due to their developmental potential. Stem cells possess the promise of providing clinicians with novel treatments for disease as well as allowing researchers to generate human-specific cellular metabolism models. Aging is a natural process of living organisms, yet aging in human heart cells is difficult to study due to the ethical considerations regarding human experimentation as well as a current lack of alternative experimental models. hPSC-derived cardiomyocytes (CMs) bear a resemblance to human cardiac cells and thus hPSC-derived CMs are considered to be a viable alternative model to study human heart cell aging. In this study, we used hPSC-derived CMs as an in vitro aging model. We generated cardiomyocytes from hPSCs and demonstrated the process of aging in both human embryonic stem cell (hESC)- and induced pluripotent stem cell (hiPSC)-derived CMs. Aging in hESC-derived CMs correlated with reduced membrane potential in mitochondria, the accumulation of lipofuscin, a slower beating pattern, and the downregulation of human telomerase RNA (hTR) and cell cycle regulating genes. Interestingly, the expression of hTR in hiPSC-derived CMs was not significantly downregulated, unlike in hESC-derived CMs. In order to delay aging, vitamin C was added to the cultured CMs. When cells were treated with 100 μM of vitamin C for 48 h, anti-aging effects, specifically on the expression of telomere-related genes and their functionality in aging cells, were observed. Taken together, these results suggest that hPSC-derived CMs can be used as a unique human cardiomyocyte aging model in vitro and that vitamin C shows anti-aging effects in this model.

  5. 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.

  6. Estimating 14C groundwater ages in a methanogenic aquifer

    USGS Publications Warehouse

    Aravena, Ramon; Wassenaar, Leonard I; Plummer, L. Niel

    1995-01-01

    This paper addresses the problem of 14C age dating of groundwaters in a confined regional aquifer affected by methanogenesis. Increasing CH4 concentrations along the groundwater flow system and 13C and 14C isotopic data for dissolved inorganic carbon, dissolved organic carbon, and CH4 clearly show the effect of methanogenesis on groundwater chemistry. Inverse reaction path modeling using NETPATH indicates the predominant geochemical reactions controlling the chemical evolution of groundwater in the aquifer are incongruent dissolution of dolomite, ion exchange, methanogenesis, and oxidation of sedimentary organic matter. Modeling of groundwater 14C ages using NETPATH indicates that a significant part of groundwater in the Alliston aquifer is less than 13,000 years old; however, older groundwater in the range of 15,000–23,000 years is also present in the aquifer. This paper demonstrates that 14C ages calculated using NETPATH, incorporating the effects of methanogenesis on the carbon pools, provide reasonable groundwater ages that were not possible by other isotopic methods.

  7. Estimation of daily mean air temperature from satellite derived radiometric data

    NASA Technical Reports Server (NTRS)

    Phinney, D.

    1976-01-01

    The Screwworm Eradication Data System (SEDS) at JSC utilizes satellite derived estimates of daily mean air temperature (DMAT) to monitor the effect of temperature on screwworm populations. The performance of the SEDS screwworm growth potential predictions depends in large part upon the accuracy of the DMAT estimates.

  8. 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.

  9. Accuracy of age estimation methods from orthopantomograph in forensic odontology: a comparative study.

    PubMed

    Khorate, Manisha M; Dinkar, A D; Ahmed, Junaid

    2014-01-01

    Changes related to chronological age are seen in both hard and soft tissue. A number of methods for age estimation have been proposed which can be classified in four categories, namely, clinical, radiological, histological and chemical analysis. In forensic odontology, age estimation based on tooth development is universally accepted method. The panoramic radiographs of 500 healthy Goan, Indian children (250 boys and 250 girls) aged between 4 and 22.1 years were selected. Modified Demirjian's method (1973/2004), Acharya AB formula (2011), Dr Ajit D. Dinkar (1984) regression equation, Foti and coworkers (2003) formula (clinical and radiological) were applied for estimation of age. The result of our study has shown that Dr Ajit D. Dinkar method is more accurate followed by Acharya Indian-specific formula. Furthermore, in this study by applying all these methods to one regional population, we have attempted to present dental age estimation methodology best suited for the Goan Indian population.

  10. 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).

  11. 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.

  12. 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.

  13. 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.

  14. Dental cementum in age estimation: a polarized light and stereomicroscopic study.

    PubMed

    Kasetty, Sowmya; Rammanohar, M; Raju Ragavendra, T

    2010-05-01

    Dental hard tissues are good candidates for age estimation as they are less destructive and procedures to determine age can be easily performed. Although cementum annulations and cementum thickness are important parameters in this regard, they are seldom used. This study was undertaken to review the methods, difficulties in execution of techniques, and accuracy of cementum thickness and annulations in estimating the age. Unstained and stained ground sections of tooth were used to measure cemental thickness and count cemental annulations based on which age was estimated and was compared with known age. Although there was positive relation between cemental thickness and annulations with age, only in 1-1.5% of cases, age could be predicted with accuracy.

  15. Age estimation in Portuguese population: The application of the London atlas of tooth development and eruption.

    PubMed

    Pavlović, Strahinja; Palmela Pereira, Cristiana; Vargas de Sousa Santos, Rui Filipe

    2017-03-01

    Chronological age estimation from the dental parameters is becoming increasingly important. The London atlas of tooth development is the most recent developed method and represents a modification of the previous older methods. The aim of this study was to evaluate the accuracy of the London atlas for the dental age estimation in the Portuguese population. The study sample included 736 radiographic images (498 females and 238 males) of Portuguese origin, patients of Dental Clinic of Superior Institute of Health Sciences Egas Moniz and Dental Medicine Faculty, University of Lisbon. The age range of the individuals was between 3 and 24 years. Estimated age was compared with the chronological age using the paired t-test. The results showed that there was no statistically significant difference between left and right side of the jaw (p>0.05). Both sides showed an average overestimation of age by one month approximately. Moreover, the significant difference between chronological and estimated age was not observed in the females. However, the significant difference was observed in a sample coming from males (right: p=0.008; left: p=0.003). Our results showed that the London atlas can be potentially used as a tool for age estimation. However, the difference between sexes clearly suggests that separate charts should be made for each sex. Further studies, which will have as a final goal the development of a new method for age estimation using dental parameters, are needed.

  16. [Some notes on methods of age estimation: an attempt in a Sundanese village, West Java].

    PubMed

    Igarashi, T

    1982-09-01

    This study is concerned with the problem of age misstatement in Indonesia. The author first presents an analysis of age data that were collected directly from the population of a Sundanese village in West Java and that indicate the extent of the problem. Various approaches used to estimate age and the problems associated with their use are then described. (summary in ENG)

  17. 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.

  18. A BAYESIAN APPROACH TO DERIVING AGES OF INDIVIDUAL FIELD WHITE DWARFS

    SciTech Connect

    O'Malley, Erin M.; Von Hippel, Ted; Van Dyk, David A. E-mail: dvandyke@imperial.ac.uk

    2013-09-20

    We apply a self-consistent and robust Bayesian statistical approach to determine the ages, distances, and zero-age main sequence (ZAMS) masses of 28 field DA white dwarfs (WDs) with ages of approximately 4-8 Gyr. Our technique requires only quality optical and near-infrared photometry to derive ages with <15% uncertainties, generally with little sensitivity to our choice of modern initial-final mass relation. We find that age, distance, and ZAMS mass are correlated in a manner that is too complex to be captured by traditional error propagation techniques. We further find that the posterior distributions of age are often asymmetric, indicating that the standard approach to deriving WD ages can yield misleading results.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. Improved age modelling and high-precision age estimates of late Quaternary tephras, for accurate palaeoclimate reconstruction

    NASA Astrophysics Data System (ADS)

    Blockley, Simon P. E.; Bronk Ramsey, C.; Pyle, D. M.

    2008-10-01

    The role of tephrochronology, as a dating and stratigraphic tool, in precise palaeoclimate and environmental reconstruction, has expanded significantly in recent years. The power of tephrochronology rests on the fact that a tephra layer can stratigraphically link records at the resolution of as little as a few years, and that the most precise age for a particular tephra can be imported into any site where it is found. In order to maximise the potential of tephras for this purpose it is necessary to have the most precise and robustly tested age estimate possible available for key tephras. Given the varying number and quality of dates associated with different tephras it is important to be able to build age models to test competing tephra dates. Recent advances in Bayesian age modelling of dates in sequence have radically extended our ability to build such stratigraphic age models. As an example of the potential here we use Bayesian methods, now widely applied, to examine the dating of some key Late Quaternary tephras from Italy. These are: the Agnano Monte Spina Tephra (AMST), the Neapolitan Yellow Tuff (NYT) and the Agnano Pomici Principali (APP), and all of them have multiple estimates of their true age. Further, we use the Bayesian approaches to generate a revised mixed radiocarbon/varve chronology for the important Lateglacial section of the Lago Grande Monticchio record, as a further illustration of what can be achieved by a Bayesian approach. With all three tephras we were able to produce viable model ages for the tephra, validate the proposed 40Ar/ 39Ar age ranges for these tephras, and provide relatively high precision age models. The results of the Bayesian integration of dating and stratigraphic information, suggest that the current best 95% confidence calendar age estimates for the AMST are 4690-4300 cal BP, the NYT 14320-13900 cal BP, and the APP 12380-12140 cal BP.

  6. Estimation of age of Dali-Ganis rifting and associated volcanic activity, Venus

    NASA Technical Reports Server (NTRS)

    Basilevsky, A. T.

    1993-01-01

    This paper deals with the estimation of age for the Dali and Ganis Chasma rift zones and their associated volcanism based on photogeologic analysis of stratigraphic relations of rift-associated features with impact craters which have associated features indicative of their age. The features are radar-dark and parabolic, and they are believed to be mantles of debris derived from fallout of the craters' ejecta. They are thought to be among the youngest features on the Venusian surface, so their 'parent' craters must also be very young, evidently among the youngest 10 percent of Venus' crater population. Dali Chasma and Ganis Chasma are a part of a system of rift zones contained within eastern Aphrodite and Atla Regio which is a significant component of Venus tectonics. The rifts of this system are fracture belts which dissect typical Venusian plains with rare islands of tessera terrain. The rift zone system consists of several segments following each other (Diane, Dali, Ganis) and forming the major rift zone line, about 10,000 km long, which has junctions with several other rift zones, including Parga Chasma Rift. The junctions are usually locations of rift-associated volcanism in the form of volcanic edifices (Maat and Ozza Montes) or plain-forming flows flooding some areas within the rift zones and the adjacent plains.

  7. [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.

  8. 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.

  9. 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.

  10. Temporal development of total chlorine in the high-latitude stratosphere based on reference distributions of mean age derived from CO2 and SF6

    NASA Astrophysics Data System (ADS)

    Engel, Andreas; Strunk, Martin; Müller, Melanie; Haase, Hans-Peter; Poss, Christian; Levin, Ingeborg; Schmidt, Ulrich

    2002-06-01

    We present balloon-borne observations of CO2 and SF6 and derived vertical profiles of mean age for polar winter (inside vortex) and for midlatitude (nonwinter) conditions. For SF6-derived mean ages above 5 years a mesospheric SF6 sink may lead to an overestimation of mean age, while for younger mean ages (below 2 years) the seasonal cycle of CO2 may influence the mean age determination based on CO2. We suggest that SF6 be used as an age tracer in the lower part of the stratosphere (i.e., for low mean age), whereas CO2 will be the better age tracer for older air. The mean age distributions together with an estimate of the width of the age spectrum are used to estimate the stratospheric chlorine loading. On the basis of an emission scenario and the lifetimes of chlorine-containing compounds we estimate the future stratospheric chlorine loading. Inside the polar vortex, at an altitude of 20 km, we expect total chlorine to return to the values present in this region in 1980, when the ozone hole first appeared, around the year 2060. This estimate is based on the assumption that the general transport characteristics will not change over the period of the analysis and can thus be regarded as a best estimate based on stationary transport, the assumed set of lifetimes and emissions, and the mean age distribution derived from our measurements. As other factors influencing ozone may undergo temporal changes, this does not mean that ozone will necessarily recover at this time. While total chlorine is probably a good proxy for inorganic chlorine at altitudes above 20 km inside the polar vortex, the changing halocarbon mix may actually lead to an earlier return of inorganic chlorine to pre-ozone-hole values at lower altitudes.

  11. Accuracy of dental age estimation in Venezuelan children: comparison of Demirjian and Willems methods.

    PubMed

    Medina, Aída C; Blanco, Lucila

    2014-01-01

    Dental age is a somatic maturity indicator with importance in clinical and forensic dentistry. The purpose of this study is to compare the applicability of the Demirjian and Willems methods for dental age estimation in a group of Venezuelan children. Panoramic radiographs of 238 Venezuelan children aged 5-13 years were used to assess dental age using the methods described by Demirjian and Willems. Children with unclear panoramic radiographs, dental agenesis, and premature loss of primary teeth were excluded. Mean differences between dental age and chronological age by gender and age groups were estimated (ANOVA, Student tests p = 0.05). For the Demirjian method, the mean difference between dental age and chronological age was 0.62 +/- 0.93 years, statistically significant. The mean overestimation was lower for females than for males (females 0.56 +/- 0.96 years, males 0.67 +/- 0.93 years). For the Willems method, the mean difference between dental age and chronological age was 0.15 +/- 0.97 years, not statistically significant. Accuracy was significantly different between genders, performing best for females (females 0.01 +/- 0.96 years, males 0.29 +/- 0.96 years). The Willems method for age estimation was found to be more accurate than the Demirjian method in this sample of Venezuelan children.

  12. 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

  13. Recollection, not familiarity, decreases in healthy aging: Converging evidence from four estimation methods

    PubMed Central

    Koen, Joshua D.; Yonelinas, Andrew P.

    2014-01-01

    Although it is generally accepted that aging is associated with recollection impairments, there is considerable disagreement surrounding how healthy aging influences familiarity-based recognition. One factor that might contribute to the mixed findings regarding age differences in familiarity is the estimation method used to quantify the two mnemonic processes. Here, this issue is examined by having a group of older adults (N = 39) between 40 and 81 years of age complete Remember/Know (RK), receiver operating characteristic (ROC), and process dissociation (PD) recognition tests. Estimates of recollection, but not familiarity, showed a significant negative correlation with chronological age. Inconsistent with previous findings, the estimation method did not moderate the relationship between age and estimations of recollection and familiarity. In a final analysis, recollection and familiarity were estimated as latent factors in a confirmatory factor analysis (CFA) that modeled the covariance between measures of free recall and recognition, and the results converged with the results from the RK, PD, and ROC tasks. These results are consistent with the hypothesis that episodic memory declines in older adults are primary driven by recollection deficits, and also suggest that the estimation method plays little to no role in age-related decreases in familiarity. PMID:25485974

  14. 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.

  15. Random regression models on Legendre polynomials to estimate genetic parameters for weights from birth to adult age in Canchim cattle.

    PubMed

    Baldi, F; Albuquerque, L G; Alencar, M M

    2010-08-01

    The objective of this work was to estimate covariance functions for direct and maternal genetic effects, animal and maternal permanent environmental effects, and subsequently, to derive relevant genetic parameters for growth traits in Canchim cattle. Data comprised 49,011 weight records on 2435 females from birth to adult age. The model of analysis included fixed effects of contemporary groups (year and month of birth and at weighing) and age of dam as quadratic covariable. Mean trends were taken into account by a cubic regression on orthogonal polynomials of animal age. Residual variances were allowed to vary and were modelled by a step function with 1, 4 or 11 classes based on animal's age. The model fitting four classes of residual variances was the best. A total of 12 random regression models from second to seventh order were used to model direct and maternal genetic effects, animal and maternal permanent environmental effects. The model with direct and maternal genetic effects, animal and maternal permanent environmental effects fitted by quadric, cubic, quintic and linear Legendre polynomials, respectively, was the most adequate to describe the covariance structure of the data. Estimates of direct and maternal heritability obtained by multi-trait (seven traits) and random regression models were very similar. Selection for higher weight at any age, especially after weaning, will produce an increase in mature cow weight. The possibility to modify the growth curve in Canchim cattle to obtain animals with rapid growth at early ages and moderate to low mature cow weight is limited.

  16. 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

  17. 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.

  18. Egg flotation estimates nest age for Pacific and Red-throated Loons

    USGS Publications Warehouse

    Rizzolo, Daniel; Schmutz, Joel A.

    2007-01-01

    We used Pacific Loon (Gavia pacifica) and Red-throated Loon (G. stellata) nests with known ages to gauge the efficacy of egg flotation for determining nest age in coastal Alaska. Egg flotation accurately estimated nest age for both species; the mean ± 1SD difference between known age and age determined with egg flotation was - 0.05 ± 2.00 d and -0.02 ± 1.63 d for Pacific and Red-throated Loons, respectively. Day of nest initiation did not influence the relationship between known nest age and nest age estimated with egg flotation, indicating incubation period was not shortened in nests initiated later in the season. Additionally, we found no difference in the ability of egg flotation to estimate nest age between two widely dispersed study sites for Pacific Loons, and only a small difference between two of three widely dispersed study sites for Red-throated Loons. Thus, our described relationships between egg flotation categories and nest age should be broadly applicable for these holarctic species. We conclude that for Pacific and Red-throated Loons, egg flotation is a useful technique for determining nest age in the field to better monitor nest fate, and to quantify nest age effects on nest daily survival rate.

  19. First rib metamorphosis: its possible utility for human age-at-death estimation.

    PubMed

    Kunos, C A; Simpson, S W; Russell, K F; Hershkovitz, I

    1999-11-01

    Human first ribs demonstrate predictable, sequential changes in shape, size, and texture with increasing age, and thus, can be used as an indicator of age at death. Metamorphosis of the first rib's head, tubercle, and costal face was documented in a cross-sectional sample of preadult and adult first ribs of known age at death from the Hamann-Todd skeletal collection (Cleveland Museum of Natural History, Cleveland, Ohio). Blind tests of the usefulness of the first rib as an age indicator were conducted, including tabulation of intraobserver and interobserver inaccuracies and biases. First rib age estimates show inaccuracies and biases by decade comparable to those generated by other aging techniques. Indeed, the first rib method is useful as an isolated age indicator. When used in conjunction with other age indicators, the first rib improves the quality of summary age assessments.

  20. Forensic age estimation in human skeletal remains: current concepts and future directions.

    PubMed

    Franklin, Daniel

    2010-01-01

    Skeletal identification has a long tradition in both physical and forensic anthropology. The process generally begins with formulation of a biological profile (osteobiography); specifically, estimation of sex, age, ethnicity and stature. The present paper briefly reviews a selection of the principal methods used for one aspect of the identification process; the estimation of personal age. It is well-documented that variability in the morphological features used to assess age in the human skeleton progressively increases from birth to old age. Thus choice of method is inherently related to whether unidentified remains are those of a juvenile or an adult. This review, therefore, considers methods appropriate for age estimation in both juvenile and adult remains; the former being primarily based on developmental, and the latter degenerative, morphological features. Such a review is timely as new methods are constantly being developed, concurrent with refinements to those already well established in mainstream anthropology.

  1. Microglia-aging: roles of microglial lysosome- and mitochondria-derived reactive oxygen species in brain aging.

    PubMed

    Nakanishi, Hiroshi; Wu, Zhou

    2009-07-19

    The accumulation of lysosome- and mitochondria-derived reactive oxygen species (ROS) are the most important causative factors for aging. Autophagic dysfunction and mitochondrial DNA damage in the central nervous system (CNS) are prominently found in microglia, the resident mononuclear phagocyte population within the CNS. The autophagic dysfunction may induce the defective turnover of mitochondria, which results in the accumulation of ROS-hypergenerating older mitochondria in microglia. ROS activate redox-dependent transduction cascades and transcription factors, including nuclear factor-kappaB, which induce the expression of inflammatory genes. Therefore, "microglia-aging" could function as a major driver for brain aging. Furthermore, the prevention of lysosomal autophagic dysfunction and mitochondrial DNA damage in microglia may therefore be a potentially effective new pharmaceutical intervention against brain aging.

  2. 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.

  3. 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

  4. 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.

  5. Drinking water contribution to aggregate perchlorate intake of reproductive-age women in the United States estimated by dietary intake simulation and analysis of urinary excretion data.

    PubMed

    Mendez, William; Dederick, Elizabeth; Cohen, Jonathan

    2010-05-01

    Estimates of perchlorate intake by the US population can be derived from either urinary excretion data or through simulation of dietary intake. Estimates from surveys of urinary excretion (NHANES) are subject to substantial uncertainty owing to the small numbers of subjects for which data are currently available. In addition, current excretion estimates are derived from "spot" urine samples and include a component of short-term (intra-day) variability that may give biased estimates of the variability in average daily intakes. Previous dietary estimates have generally not included any contribution from drinking water, owing to a lack of data related to perchlorate concentrations in water supplies. In this paper, we derive simulation (Monte Carlo) estimates of dietary perchlorate intake distributions for reproductive-age women, which include explicit contributions from drinking water, and compare them to estimates based on urinary excretion. Perchlorate concentrations in water were estimated based on measurements from the US Environmental Protection Agency's UCMR1 database, and from other regional studies of perchlorate contamination. We find that including the drinking water contributions in the dietary simulations yields increases in the population's geometric mean perchlorate intake of 3-8 percent, with a conservative maximum of about 24 percent, compared to intakes estimated based on food intake alone. The intake distributions estimated from dietary and water consumption were found to be very similar to estimates based on creatinine-adjusted perchlorate excretion data from the NHANES, except for having lower population variability. When the dietary simulation data were adjusted to include a contribution from short-term variability similar to that in the "spot" urine samples, the variability in the NHANES and diet-derived estimates were found to be very similar. Our analyses indicate that a reasonable upper-bound estimate for the 95th percentile perchlorate intake

  6. Age and motives for volunteering: testing hypotheses derived from socioemotional selectivity theory.

    PubMed

    Okun, Morris A; Schultz, Amy

    2003-06-01

    Following a meta-analysis of the relations between age and volunteer motives (career, understanding, enhancement, protective, making friends, social, and values), the authors tested hypotheses derived from socioemotional selectivity theory regarding the effects of age on these volunteer motives. The Volunteer Functions Inventory was completed by 523 volunteers from 2 affiliates of the International Habitat for Humanity. Multiple regression analyses revealed, as predicted, that as age increases, career and understanding volunteer motivation decrease and social volunteer motivation increases. Contrary to expectations, age did not contribute to the prediction of enhancement, protective, and values volunteer motivations and the relation between age and making friends volunteer motivation was nonlinear. The results were discussed in the context of age-differential and age-similarity perspectives on volunteer motivation.

  7. Development of a biometric method to estimate age on hand radiographs.

    PubMed

    Remy, Floriane; Hossu, Gabriela; Cendre, Romain; Micard, Emilien; Mainard-Simard, Laurence; Felblinger, Jacques; Martrille, Laurent; Lalys, Loïc

    2017-02-01

    Age estimation of living individuals aged less than 13, 18 or 21 years, which are some relevant legal ages in most European countries, is currently problematic in the forensic context. Thus, numerous methods are available for legal authorities, although their efficiency can be discussed. For those reasons, we aimed to propose a new method, based on the biometric analysis of hand bones. 451 hand radiographs of French individuals under the age of 21 were retrospectively analyzed. This total sample was divided into three subgroups bounded by the relevant legal ages previously mentioned: 0-13, 13-18 and 18-21 years. On these radiographs, we numerically applied the osteometric board method used in anthropology, by including each metacarpal and proximal phalange of the five hand rays in the smallest rectangle possible. In that we can access their length and width information thanks to a measurement protocol developed precisely for our treatment with the ORS Visual(®) software. Then, a statistical analysis was performed from these biometric data: a Linear Discriminant Analysis (LDA) evaluated the probability for an individual to belong to one of the age group (0-13, 13-18 or 18-21); and several multivariate regression models were tested for the establishment of age estimation formulas for each of these age groups. The mean Correlation Coefficient between chronological age and both lengths and widths of hand bones is equal to 0.90 for the total sample. Repeatability and reproducibility were assessed. The LDA could more easily predict the belonging to the 0-13 age group. Age can be estimated with a mean standard error which never exceeds 1 year for the 95% confidence interval. Finally, compared to the literature, we can conclude that estimating an age from the biometric information of metacarpals and proximal phalanges is promising.

  8. 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

  9. 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.

  10. 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.

  11. Service Lifetime Estimation of EPDM Rubber Based on Accelerated Aging Tests

    NASA Astrophysics Data System (ADS)

    Liu, Jie; Li, Xiangbo; Xu, Likun; He, Tao

    2017-02-01

    Service lifetime of ethylene propylene diene monomer (EPDM) rubber at room temperature (25 °C) was estimated based on accelerated aging tests. The study followed sealing stress loss on compressed cylinder samples by compression stress relaxation methods. The results showed that the cylinder samples of EPDM can quickly reach the physical relaxation equilibrium by using the over-compression method. The non-Arrhenius behavior occurred at the lowest aging temperature. A significant linear relationship was observed between compression set values and normalized stress decay results, and the relationship was not related to the ambient temperature of aging. It was estimated that the sealing stress loss in view of practical application would occur after around 86.8 years at 25 °C. The estimations at 25 °C based on the non-Arrhenius behavior were in agreement with compression set data from storage aging tests in natural environment.

  12. Age Estimation in Living Egyptians Using Signal Joint T-cell Receptor Excision Circle Rearrangement.

    PubMed

    Ibrahim, Samah F; Gaballah, Iman F; Rashed, Laila A

    2016-07-01

    Age estimation is one of the challenges in forensic sciences. There are many techniques to estimate the age. Molecular biology approach is one of these techniques. Signal joint T-cell receptor excision circles gene (sjTRECs), is one of this approach. We aimed to use sjTRECs as a suitable marker for age estimation among Egyptian population. TaqMan qPCR approach was used to quantify sjTREC levels in blood samples obtained from 153 healthy Egyptian individuals ranging from a few weeks to 70 years. Our results showed a significant negative correlation between sjTREC levels and age with p ≤ 0.05. Moreover, the individual's age can be determined through this formula Age = -30.671+ (-5.998Y) (Y is dCtTBP - sjTREC) with standard error ±7.35 years. Within the forensic context, sjTREC' levels can be used to estimate the Egyptian individual's age accurately.

  13. Clonal diversity and estimation of relative clone age: application to agrobiodiversity of yam (Dioscorea rotundata)

    PubMed Central

    2013-01-01

    Background Clonal propagation is a particular reproductive system found in both the plant and animal kingdoms, from human parasites to clonally propagated crops. Clonal diversity provides information about plant and animal evolutionary history, i.e. how clones spread, or the age of a particular clone. In plants, this could provide valuable information about agrobiodiversity dynamics and more broadly about the evolutionary history of a particular crop. We studied the evolutionary history of yam, Dioscorea rotundata. In Africa, Yam is cultivated by tuber clonal propagation. Results We used 12 microsatellite markers to identify intra-clonal diversity in yam varieties. We then used this diversity to assess the relative ages of clones. Using simulations, we assessed how Approximate Bayesian Computation could use clonal diversity to estimate the age of a clone depending on the size of the sample, the number of independent samples and the number of markers. We then applied this approach to our particular dataset and showed that the relative ages of varieties could be estimated, and that each variety could be ranked by age. Conclusions We give a first estimation of clone age in an approximate Bayesian framework. However the precise estimation of clone age depends on the precision of the mutation rate. We provide useful information on agrobiodiversity dynamics and suggest recurrent creation of varietal diversity in a clonally propagated crop. PMID:24219837

  14. The influence of body size on adult skeletal age estimation methods.

    PubMed

    Merritt, Catherine E

    2015-01-01

    Accurate age estimations are essential to archaeological and forensic analyses. However, reliability for adult skeletal age estimations is poor, especially for individuals over the age of 40 years. This is the first study to show that body size influences skeletal age estimation. The İşcan et al., Lovejoy et al., Buckberry and Chamberlain, and Suchey-Brooks age methods were tested on 764 adult skeletons from the Hamann-Todd and William Bass Collections. Statures ranged from 1.30 to 1.93 m and body masses ranged from 24.0 to 99.8 kg. Transition analysis was used to evaluate the differences in the age estimations. For all four methods, the smallest individuals have the lowest ages at transition and the largest individuals have the highest ages at transition. Short and light individuals are consistently underaged, while tall and heavy individuals are consistently overaged. When femoral length and femoral head diameter are compared with the log-age model, results show the same trend as the known stature and body mass measurements. The skeletal remains of underweight individuals have fewer age markers while those of obese individuals have increased surface degeneration and osteophytic lipping. Tissue type and mechanical loading have been shown to affect bone turnover rates, and may explain the differing patterns of skeletal aging. From an archaeological perspective, the underaging of light, short individuals suggests the need to revisit the current research consensus on the young mortality rates of past populations. From a forensic perspective, understanding the influence of body size will impact efforts to identify victims of mass disasters, genocides, and homicides.

  15. Setting the light conditions for measuring root transparency for age-at-death estimation methods.

    PubMed

    Adserias-Garriga, Joe; Nogué-Navarro, Laia; Zapico, Sara C; Ubelaker, Douglas H

    2017-03-30

    Age-at-death estimation is one of the main goals in forensic identification, being an essential parameter to determine the biological profile, narrowing the possibility of identification in cases involving missing persons and unidentified bodies. The study of dental tissues has been long considered as a proper tool for age estimation with several age estimation methods based on them. Dental age estimation methods can be divided into three categories: tooth formation and development, post-formation changes, and histological changes. While tooth formation and growth changes are important for fetal and infant consideration, when the end of dental and skeletal growth is achieved, post-formation or biochemical changes can be applied. Lamendin et al. in J Forensic Sci 37:1373-1379, (1992) developed an adult age estimation method based on root transparency and periodontal recession. The regression formula demonstrated its accuracy of use for 40 to 70-year-old individuals. Later on, Prince and Ubelaker in J Forensic Sci 47(1):107-116, (2002) evaluated the effects of ancestry and sex and incorporated root height into the equation, developing four new regression formulas for males and females of African and European ancestry. Even though root transparency is a key element in the method, the conditions for measuring this element have not been established. The aim of the present study is to set the light conditions measured in lumens that offer greater accuracy when applying the Lamendin et al. method modified by Prince and Ubelaker. The results must be also taken into account in the application of other age estimation methodologies using root transparency to estimate age-at-death.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. Accurate estimates of age at maturity from the growth trajectories of fishes and other ectotherms.

    PubMed

    Honsey, Andrew E; Staples, David F; Venturelli, Paul A

    2017-01-01

    Age at maturity (AAM) is a key life history trait that provides insight into ecology, evolution, and population dynamics. However, maturity data can be costly to collect or may not be available. Life history theory suggests that growth is biphasic for many organisms, with a change-point in growth occurring at maturity. If so, then it should be possible to use a biphasic growth model to estimate AAM from growth data. To test this prediction, we used the Lester biphasic growth model in a likelihood profiling framework to estimate AAM from length at age data. We fit our model to simulated growth trajectories to determine minimum data requirements (in terms of sample size, precision in length at age, and the cost to somatic growth of maturity) for accurate AAM estimates. We then applied our method to a large walleye Sander vitreus data set and show that our AAM estimates are in close agreement with conventional estimates when our model fits well. Finally, we highlight the potential of our method by applying it to length at age data for a variety of ectotherms. Our method shows promise as a tool for estimating AAM and other life history traits from contemporary and historical samples.

  3. 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

  4. 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.

  5. Empirical age spectra in the lower stratosphere derived from in-situ measurements of halocarbons during TACTS/ESMVal

    NASA Astrophysics Data System (ADS)

    Boenisch, Harald; Engel, Andreas; Keber, Timo

    2014-05-01

    The age spectrum is the transit time distribution of the fluid constituents in a specific stratospheric air parcel and therefore contains all the information of the air parcel's transport history. Unfortunately, it is not possible to directly measure the age spectrum of a stratospheric air parcel. Only the first moment of the distribution - the mean age of air - is directly observable from observations of passive tracers like SF6 and CO2. However, it is possible to reconstruct the age spectrum from a bunch of chemical active tracers with different stratospheric lifetimes (Schoeberl et al., 2005; Ehhalt et al., 2007) assuming to first order that the age spectrum follows the analytical solution given by Hall and Plumb (1994). Here, we will present empirical age spectra in the extratropical lower stratosphere of the northern hemisphere derived from a dataset gathered during the combined campaigns TACTS (Transport and Composition in the UT/LMS) and ESMVal (Earth System Model Validation). About 20 halocarbons have been measured with the new developed in-situ GC/MS instrument GHOST-MS. These chemical active species have different stratospheric lifetimes ranging from several days (e.g. Methylbromoform) up to several decades (e.g. CFC-12). Ehhalt, D. H., Rohrer, F., Blake, D. R., Kinnison, D. E., and Konopka, P.: On the use of nonmethane hydrocarbons for the determination of age spectra in the lower stratosphere, J. Geophys. Res., 112, D12208, 10.1029/2006jd007686, 2007. Hall, T. M., and Plumb, R. A.: Age as a Diagnostic of Stratospheric Transport, J. Geophys. Res., 99, 1059-1070, 1994. Schoeberl, M. R., Douglass, A. R., Polansky, B., Boone, C., Walker, K. A., and Bernath, P.: Estimation of stratospheric age spectrum from chemical tracers, J. Geophys. Res., 110, D21303, 10.1029/2005jd006125, 2005.

  6. Estimation of Chlorophyll-a Concentration in Turbid Lake Using Spectral Smoothing and Derivative Analysis

    PubMed Central

    Cheng, Chunmei; Wei, Yuchun; Sun, Xiaopeng; Zhou, Yu

    2013-01-01

    As a major indicator of lake eutrophication that is harmful to human health, the chlorophyll-a concentration (Chl-a) is often estimated using remote sensing, and one method often used is the spectral derivative algorithm. Direct derivative processing may magnify the noise, thus making spectral smoothing necessary. This study aims to use spectral smoothing as a pretreatment and to test the applicability of the spectral derivative algorithm for Chl-a estimation in Taihu Lake, China, based on the in situ hyperspectral reflectance. Data from July–August of 2004 were used to build the model, and data from July–August of 2005 and March of 2011 were used to validate the model, with Chl-a ranges of 5.0–156.0 mg/m3, 4.0–98.0 mg/m3 and 11.4–35.8 mg/m3, respectively. The derivative model was first used and then compared with the band ratio, three-band and four-band models. The results show that the first-order derivative model at 699 nm had satisfactory accuracy (R2 = 0.75) after kernel regression smoothing and had smaller validation root mean square errors of 15.21 mg/m3 in 2005 and 5.85 mg/m3 in 2011. The distribution map of Chl-a in Taihu Lake based on the HJ1/HSI image showed the actualdistribution trend, indicating that the first-order derivative model after spectral smoothing can be used for Chl-a estimation in turbid lake. PMID:23880727

  7. Estimation of chlorophyll-a concentration in Turbid Lake using spectral smoothing and derivative analysis.

    PubMed

    Cheng, Chunmei; Wei, Yuchun; Sun, Xiaopeng; Zhou, Yu

    2013-07-16

    As a major indicator of lake eutrophication that is harmful to human health, the chlorophyll-a concentration (Chl-a) is often estimated using remote sensing, and one method often used is the spectral derivative algorithm. Direct derivative processing may magnify the noise, thus making spectral smoothing necessary. This study aims to use spectral smoothing as a pretreatment and to test the applicability of the spectral derivative algorithm for Chl-a estimation in Taihu Lake, China, based on the in situ hyperspectral reflectance. Data from July-August of 2004 were used to build the model, and data from July-August of 2005 and March of 2011 were used to validate the model, with Chl-a ranges of 5.0-156.0 mg/m3, 4.0-98.0 mg/m3 and 11.4-35.8 mg/m3, respectively. The derivative model was first used and then compared with the band ratio, three-band and four-band models. The results show that the first-order derivative model at 699 nm had satisfactory accuracy (R2 = 0.75) after kernel regression smoothing and had smaller validation root mean square errors of 15.21 mg/m3 in 2005 and 5.85 mg/m3 in 2011. The distribution map of Chl-a in Taihu Lake based on the HJ1/HSI image showed the actual distribution trend, indicating that the first-order derivative model after spectral smoothing can be used for Chl-a estimation in turbid lake.

  8. 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.

  9. 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

  10. Near infrared spectroscopy for estimating the age of malaria transmiting mosquitoes

    NASA Astrophysics Data System (ADS)

    Milali, Masabho Peter

    We explore the use of near infrared spectrometry to classifying the age of a wild malaria transmitting mosquito. In Chapter Two, using a different set of lab-reared mosquitoes, we replicate the Mayagaya et al. study of the accuracy of near-infrared spectrometry (NIRS) to estimate the age of lab-reared mosquitoes, reproducing the published accuracy. Our results strengthen the Mayagaya et. al study and increase confidence in using NIRS to estimate age classes of mosquitoes. In the field, we wish to classify the ages of wild, not lab-reared mosquitoes, but the necessary training data from wild mosquitoes is difficult to find. Applying a model trained on spectra from lab-reared mosquitoes to estimate the age of wild mosquitoes is appropriate only if spectra collected from lab-reared mosquitoes are equivalent to those collected from wild mosquitoes. In Chapter Three, we apply k-means cluster analysis to a mixture of spectra collected from lab-reared and wild Anopheles arabiensis mosquitoes to determine if there is significant difference between these spectra. We find no significant difference (P = 0.245) in distributions between the wild and lab-reared mosquitoes in the two formed clusters. The two formed clusters have average silhouette coefficient values (cluster quality measure) of 0.51 and 0.77, respectively, which shows that the clusters were reasonable and strong, respectively. Basing on results from Chapter Three, we estimate the age class of wild Anopheles arabiensis mosquitoes using a classification model trained on lab-reared Anopheles arabiensis. We validate the accuracy of the model by comparing its estimates with ovary dissection estimates. While our model estimated 86% and 14% of wild Anopheles arabiensis to be < 7 and ≥ 7 days old, respectively, ovary dissection estimated 72% as young and 28% as old. Studies show that wild mosquito populations generally consist of more young than old mosquitoes. Therefore, our model estimates age of wild mosquitoes in

  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. Estimation of fetal age from dimensions of atlas and axis ossification centers.

    PubMed

    Castellana, C; Kósa, F

    2001-03-01

    The atlas and axis ossification centers of 106 human fetal and neonate skeletons were measured. The skeletons belong to the collection in the Department of Forensic Medicine of the Albert Szent-Györgyi Medical University, Szeged, Hungary. The age of the skeletons ranged from 4 to 10 lunar months. Nine linear measurements on the atlas, seven on the axis neural arches ossification centers and three on each one of the axis centra ossification centers were taken. We did simple and multiple linear regression analysis to estimate the age of fetuses. The results show that it is possible to use regression equations to estimate the fetal body length and age from atlas and axis ossification centers measurements during the whole period of development studied. The study of size and shape of the ossification centers using factorial analysis (principal component analysis) shows that the shape of the dens of the axis might be useful to estimate fetal viability.

  13. Semi-parametric estimation of age-time specific infection incidence from serial prevalence data.

    PubMed

    Nagelkerke, N; Heisterkamp, S; Borgdorff, M; Broekmans, J; Van Houwelingen, H

    1999-02-15

    Many infections cause lasting detectable immune responses, whose prevalence can be estimated from cross-sectional surveys. However, such surveys do not provide direct information on the incidence of infection. We address the issue of estimating age and time specific incidence from a series of prevalence surveys under the assumption that incidence changes exponentially with time, but make no assumption about the age specific incidence. We show that these assumptions lead to a proportional hazards model and estimate its parameters using semi-parametric maximum likelihood methods. The method is applied to tuberculin surveys in The Netherlands to explore age dependence of the risk of tuberculous infection in the presence of a strong secular decline in this risk.

  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. 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. Reliability of age estimation from iliac auricular surface in a subactual Chilean sample.

    PubMed

    Herrera, María José; Retamal, Rodrigo

    2017-02-14

    The aim of this study was to test the reliability of Osborne et al. (2004) [8] age estimation based on the iliac auricular surface of the ilium. We selected 172 skeletons with documented sex and age-at-death and established six uniformly distributed age intervals for analysis. ANOVA was employed to assess the association of the documented age with sex and the auricular surface classification. We employed Bonferroni post-hoc tests to find any statistical differences across documented ages within each phase of Osborne's criteria. While the ANOVA showed a significant association between the documented age and the auricular surface classification, post-hoc tests found that phases 2 and 3 were the only consecutive phases with significant differences. We argue that a lack of statistical significance between consecutive phases undermines the reliability of this method for forensic purposes especially in middle adults. It may be possible that the collapse of intermediate phases would increase the accuracy of this method.

  17. The circles of life: age at death estimation in burnt teeth through tooth cementum annulations.

    PubMed

    Oliveira-Santos, Inês; Gouveia, Márcia; Cunha, Eugénia; Gonçalves, David

    2017-03-01

    Age at death estimation in burnt human remains is problematic due to the severe heat-induced modifications that may affect the skeleton after a burning event. The objective of this paper was to assess if cementochronology, which focuses on the cementum incremental lines, is a reliable method of age estimation in burnt remains. Besides the classical approach based on the counting of incremental lines, another approach based on the extrapolation of incremental lines taking into account the cement layer thickness and the incremental line thickness was investigated. A comparison of the performance of the two techniques was carried out on a sample of 60 identified monoradicular teeth that were recently extracted at dentist offices and then experimentally burnt at two maximum temperatures (400 and 900 °C). Micrographs of cross-sections of the roots were taken via an optical microscope with magnification of ×100, ×200 and ×400. Incremental line counting and measurements were carried out with the ImageJ software. Age estimation based on incremental line counting in burnt teeth had no significant correlation with chronological age (p = 0.244 to 0.914) and led to large absolute mean errors (19 to 21 years). In contrast, age estimation based on the extrapolation approach showed a significant correlation with known age (p = 0.449 to 0.484). In addition, the mean absolute error of the latter was much smaller (10 to 14 years). The reason behind this discrepancy is the heat-induced dimensional changes of incremental lines that affect their visibility and individualization thus complicating line counting. Our results indicated that incremental lines extrapolation is successful at solving this problem and that the resulting age estimation is much more reliable.

  18. 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.

  19. 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

  20. 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.

  1. A Critical Assessment of Ages Derived Using Pre-Main-Sequence Isochrones in Colour-Magnitude Diagrams

    NASA Astrophysics Data System (ADS)

    Bell, Cameron P. M.

    2012-11-01

    In this thesis a critical assessment of the ages derived using theoretical pre-main-sequence (pre-MS) stellar evolutionary models is presented by comparing the predictions to the low-mass pre-MS population of 14 young star-forming regions (SFRs) in colour-magnitude diagrams (CMDs). Deriving pre-MS ages requires precise distances and estimates of the reddening. Therefore, the main-sequence (MS) members of the SFRs have been used to derive a self-consistent set of statistically robust ages, distances and reddenings with associated uncertainties using a maximum-likelihood fitting statistic and MS evolutionary models. A photometric method for de-reddening individual stars - known as the Q-method - in regions where the extinction is spatially variable has been updated and is presented. The effects of both the model dependency and the SFR composition on these derived parameters are also discussed. The problem of calibrating photometric observations of red pre-MS stars is examined and it is shown that using observations of MS stars to transform the data into a standard photometric system can introduce significant errors in the position of the pre-MS locus in CMD space. Hence, it is crucial that precise photometric studies - especially of pre-MS objects - be carried out in the natural photometric system of the observations. This therefore requires a robust model of the system responses for the instrument used, and thus the calculated responses for the Wide-Field Camera on the Isaac Newton Telescope are presented. These system responses have been tested using standard star observations and have been shown to be a good representation of the photometric system. A benchmark test for the pre-MS evolutionary models is performed by comparing them to a set of well-calibrated CMDs of the Pleiades in the wavelength regime 0.4-2.5 μm. The masses predicted by these models are also tested against dynamical masses using a sample of MS binaries by calculating the system magnitude in a

  2. 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.

  3. 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.

  4. The study on telomere length for age estimation in a Thai population.

    PubMed

    Srettabunjong, Supawon; Satitsri, Saravut; Thongnoppakhun, Wanna; Tirawanchai, Nednapis

    2014-06-01

    Age is one of the key parameters in establishing a physical characteristic profile of an individual. For biological evidence left in crime scenes such as blood, saliva, hair, etc, the evidence owner's age can be determined only by DNA extracted from these materials. Previous researches have found that there are certain DNA regions with specialized characteristic and function called telomere being able to predict age. The present study was to determine the correlation between telomere length and age as well as the effect of sex on the correlation and to create linear regression equation for age estimation in Thai population for forensic purposes. Blood samples obtained from unrelated healthy Thai fresh cadavers without anatomical organ abnormalities were used in this study. All cadaver subjects underwent the postmortem examination in jurisdiction of the Department of Forensic Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, and Institute of Forensic Medicine, Police General Hospital. Fifty blood samples from both sexes of all ages divided into 6 groups for equal age distribution (0-11, 12-23, 24-35, 36-47, 48-59, and 60 years old and older) were collected for a total of 100 samples. The extracted genomic DNA samples were then subjected to telomere length estimation by terminal restriction fragment (TRF) assay. The results showed that the mean TRF length was inversely correlated with age (r = -0.625), and sex did not have a statistically significant influence on the association between age and mean TRF length (P > 0.05). The obtained linear regression equation was y = 113.538 ± 9.604 - 0.012 × (R = 0.391; P < 0.001). However, the correlation was too low to be used for age estimation with high certainty and a possible reason for this in part would be the postmortem DNA degradation at some level, even using fresh cadaver blood, and other biological factors such as ethnicity and DNA sources. Roughly, those individuals who had a mean TRF length

  5. 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.

  6. Histological estimation of age at death from the compact bone of burned and unburned human ribs.

    PubMed

    Absolonova, Karolina; Veleminsky, Petr; Dobisikova, Miluse; Beran, Michal; Zocova, Jarmila

    2013-01-01

    This study describes the estimation of age at death from the compact bone of burned and unburned human ribs. Bone samples came from individuals of known age, sex, and cause of death. Each bone was divided into four sections; three sections were burned at 700, 800, and 1000°C. Undecalcified, unstained ground cross sections were photographed, and 28 variables were analyzed in the bones using SigmaScan Pro 5. Age-related as well as heat-induced microstructural changes were found. These changes were often very similar and made estimating the age at death difficult in the burned bones. Differences between the sexes were found in some variables, caused by both aging and also by the different behavior of some variables during burning. Regression equations were developed to estimate age at death for unburned bones (r² = 0.579 and 0.707), bones burned at 700°C (r² = 0.453 and 0.501), and 800°C (r² = 0.334 and 0.340).

  7. 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.

  8. Age- and sex-specific estimation of dose to a normal thyroid from clinical administration of iodine-131

    SciTech Connect

    Killough, G.G.; Eckerman, K.F.

    1986-09-01

    This report describes the derivation of an age- and sex-dependent model of radioiodine dosimetry in the thyroid and the application of the model to estimating the thyroid dose for each of 4215 patients who were exposed to /sup 131/I in diagnostic and therapeutic procedures. In most cases, the data available consisted of the patient's age at the time of administration, the patient's sex, the quantity of activity administered, the clinically determined uptake of radioiodine by the thyroid, and the time after administration at which the uptake was determined. The model was made to conform to these data requirements by the use of age-specific estimates of the biological half-time of iodine in the thyroid and an age- and sex-dependent representation of the mass of the thyroid. Also, it was assumed that the thyroid burden was maximum at 24 hours after administration (the /sup 131/I dose is not critically sensitive to this assumption). The metabolic model is of the form A(t) = K x (exp(-..mu../sub 1/t) - exp(-..mu../sub 2/t)) ..mu..Ci where ..mu../sub i/ = lambda/sub r/ + lambda/sub i//sup b/ (i = 1, 2), lambda/sub r/ is the radiological decay-rate coefficient, and the lambda/sub i//sup b/ are biological removal-rate coefficients. The values of lambda/sub i//sup b/ are determined by solving a nonlinear equation that depends on assumptions about the time of maximum uptake and the eventual biological loss rate (through which age dependence enters). An addendum (Appendix C) extends the method to other radioiodines and gives age- and sex-dependent dose conversion factors for most isotopes.

  9. 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. 

  10. Evaluation of a technique for satellite-derived area estimation of forest fires

    NASA Technical Reports Server (NTRS)

    Cahoon, Donald R., Jr.; Stocks, Brian J.; Levine, Joel S.; Cofer, Wesley R., III; Chung, Charles C.

    1992-01-01

    The advanced very high resolution radiometer (AVHRR), has been found useful for the location and monitoring of both smoke and fires because of the daily observations, the large geographical coverage of the imagery, the spectral characteristics of the instrument, and the spatial resolution of the instrument. This paper will discuss the application of AVHRR data to assess the geographical extent of burning. Methods have been developed to estimate the surface area of burning by analyzing the surface area effected by fire with AVHRR imagery. Characteristics of the AVHRR instrument, its orbit, field of view, and archived data sets are discussed relative to the unique surface area of each pixel. The errors associated with this surface area estimation technique are determined using AVHRR-derived area estimates of target regions with known sizes. This technique is used to evaluate the area burned during the Yellowstone fires of 1988.

  11. Highway traffic estimation of improved precision using the derivative-free nonlinear Kalman Filter

    NASA Astrophysics Data System (ADS)

    Rigatos, Gerasimos; Siano, Pierluigi; Zervos, Nikolaos; Melkikh, Alexey

    2015-12-01

    The paper proves that the PDE dynamic model of the highway traffic is a differentially flat one and by applying spatial discretization its shows that the model's transformation into an equivalent linear canonical state-space form is possible. For the latter representation of the traffic's dynamics, state estimation is performed with the use of the Derivative-free nonlinear Kalman Filter. The proposed filter consists of the Kalman Filter recursion applied on the transformed state-space model of the highway traffic. Moreover, it makes use of an inverse transformation, based again on differential flatness theory which enables to obtain estimates of the state variables of the initial nonlinear PDE model. By avoiding approximate linearizations and the truncation of nonlinear terms from the PDE model of the traffic's dynamics the proposed filtering methods outperforms, in terms of accuracy, other nonlinear estimators such as the Extended Kalman Filter. The article's theoretical findings are confirmed through simulation experiments.

  12. 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.

  13. 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...

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

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

    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 < 0.001, RMSE = 0.58 kg). The predicted mean aboveground woody carbon storage for the study area was 677 g/m2. 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.

  16. 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.

  17. A Test of the Passalacqua Age at Death Estimation Method Using the Sacrum.

    PubMed

    Colarusso, Tara

    2016-01-01

    A test of the accuracy of the Passalacqua (J Forensic Sci, 5, 2009, 255) sacrum method in a forensic context was performed on a sample of 153 individuals from the J.C.B. Grant Skeletal Collection. The Passalacqua (J Forensic Sci, 5, 2009, 255) method assesses seven traits of the sacrum using a 7-digit coding system. An accuracy of 97.3% was achieved using the Passalacqua (J Forensic Sci, 5, 2009, 255) method to estimate adult skeletal age. On average each age estimate differed by 12.87 years from the known age. The method underestimated the age of individuals by an average of 4.3 years. An intra-observer error of 6.6% suggests that the method can be performed with precision. Correlation and regression analysis found that the sacral traits used in the Passalacqua (J Forensic Sci, 5, 2009, 255) method did not have a strong relationship with age or an ability to strongly predict age. Overall, the method was not practical for use in a forensic context due to the broad age ranges, despite the high accuracy and low intra-observer error.

  18. 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

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

    PubMed

    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.

  20. 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.

  1. 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…

  2. Age at Marriage as a Mobility Contingency: Estimates for the Nye-Berardo Model

    ERIC Educational Resources Information Center

    Call, Vaughn R. A.; Otto, Luther B.

    1977-01-01

    This study provides estimates for the Nye and Berardo model of the effect of age at marriage on socioeconomic attainments. The major findings are that marital timing has neither a total effect on educational and occupational attainments, nor does it mediate the total effects of family socioeconomic statuses. (Author)

  3. 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

  4. Statistical Design and Estimation for the National Social Life, Health, and Aging Project

    PubMed Central

    Eckman, Stephanie; Smith, Stephen

    2009-01-01

    Objectives The paper discusses the sample design of the National Social Life, Health, and Aging Project (NSHAP) and how the design affects how estimates should be calculated from the survey data. The NSHAP study allows researchers to study the links between sexuality and health in older adults. The goal of the design was to represent adults aged 57–85 years in six demographic domains. Methods The sample design begins with a national area probability sample of households, carried out jointly with the 2004 round of the Health and Retirement Study. Selection of respondents for NSHAP balanced age and gender subgroups and oversampled African Americans and Latinos. Data collection was carried out from July 2005 to March 2006. Results The survey obtained an overall response rate of 75.5%. Discussion The complex sample design requires that the selection probabilities and the field implementation be accounted for in estimating population parameters. The data set contains weights to compensate for differential probabilities of selection and response rates among demographic groups. Analysts should use weights in constructing estimates from the survey and account for the complex sample design in estimating standard errors for survey estimates. PMID:19567827

  5. The receptor for advanced glycation end products (RAGE) specifically recognizes methylglyoxal-derived AGEs.

    PubMed

    Xue, Jing; Ray, Rashmi; Singer, David; Böhme, David; Burz, David S; Rai, Vivek; Hoffmann, Ralf; Shekhtman, Alexander

    2014-05-27

    Diabetes-induced hyperglycemia increases the extracellular concentration of methylglyoxal. Methylglyoxal-derived hydroimidazolones (MG-H) form advanced glycation end products (AGEs) that accumulate in the serum of diabetic patients. The binding of hydroimidozolones to the receptor for AGEs (RAGE) results in long-term complications of diabetes typified by vascular and neuronal injury. Here we show that binding of methylglyoxal-modified albumin to RAGE results in signal transduction. Chemically synthesized peptides containing hydroimidozolones bind specifically to the V domain of RAGE with nanomolar affinity. The solution structure of an MG-H1-V domain complex revealed that the hydroimidazolone moiety forms multiple contacts with a positively charged surface on the V domain. The high affinity and specificity of hydroimidozolones binding to the V domain of RAGE suggest that they are the primary AGE structures that give rise to AGEs-RAGE pathologies.

  6. 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

  7. Variation in osteon histomorphometrics and their impact on age-at-death estimation in older individuals.

    PubMed

    Goliath, Jesse R; Stewart, Marissa C; Stout, Sam D

    2016-05-01

    Histomorphometric studies have reported relations between osteon size and age; however, data focused on the shape of osteons is sparse. The purpose of this study was to determine how osteon circularity (On.Cr) varies with age in different skeletal elements. Regression analysis was used to evaluate the relationship between age and osteon shape and size. We hypothesized that age would be negatively related to osteon size (area, On.Ar) and positively related to osteon shape (On.Cr). On.Cr and On.Ar were determined for the ribs and femora of 27 cadaveric specimens with known age-at-death. As predicted, age was significantly related to osteon size and shape for both the femur and rib. With age, there was a decrease in size and an increase in circularity. No relationship between sex and On.Cr was detected. An age predicting model, including On.Cr, On.Ar and OPD, is proposed to improve our ability to estimate age-at-death, especially for older individuals.

  8. Murine cardiosphere-derived cells are impaired by age but not by cardiac dystrophic dysfunction.

    PubMed

    Hsiao, Lien-Cheng; Perbellini, Filippo; Gomes, Renata S M; Tan, Jun Jie; Vieira, Silvia; Faggian, Giuseppe; Clarke, Kieran; Carr, Carolyn A

    2014-05-01

    To be clinically relevant as a therapy for heart failure, endogenous progenitor cells must be isolated and expanded from aged and/or diseased tissue. Here, we investigated the effect of age and cardiac impairment resulting from lack of dystrophin on murine cardiosphere-derived cells (CDCs). CDCs were isolated and expanded from atrial biopsies from wild-type mice aged 1.5, 6, 18, and 24 months and from mdx mice aged 6 and 18 months. Cardiac function was measured in mdx mice and age-matched wild-type mice using high-resolution cine magnetic resonance imaging. CDCs could be isolated and expanded from all mice, however, the number of cells obtained, and their regenerative potential, decreased with age, as demonstrated by decreased expression of stem cell markers, c-kit and Sca-1, and decreased cell proliferation, migration, clonogenicity, and differentiation. Six-month-old mdx mice showed right ventricular (RV) dilation and reduced RV ejection fraction (EF) in comparison to wild-type mice. Older mdx mice displayed significant RV and left ventricular dilation and decreased EF in both ventricles, compared with age-matched wild-type mice. Mdx mouse hearts contained significantly more fibrotic tissue than age-matched wild-type mouse hearts. However, CDCs isolated from mice aged 6 and 18 months had the same number and regenerative potential from mdx mice and age-matched wild-type mice. Thus, the cardiac progenitor cell population is impaired by age but is not substantially altered by the progressive deterioration in function of the dystrophic heart.

  9. 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

  10. Simultaneous estimation of unwrapped phase and phase derivative from a closed fringe pattern

    NASA Astrophysics Data System (ADS)

    Kulkarni, Rishikesh; Rastogi, Pramod

    2016-12-01

    We propose a new approach for the direct estimation of the unwrapped phase from a single closed fringe pattern. The fringe analysis is performed along a given row/column at a time by approximating the phase with a weighted linear combination of linearly independent basis functions. Gaussian radial basis functions with equally distributed centers and a fixed variance are considered for the phase approximation. A state space model is defined with the weights of the basis functions as the state vector elements. Extended Kalman filter is effectively utilized for the accurate state estimation. A fringe density estimation based criteria is established to select whether the phase estimation is performed in a row by row or column by column manner. In the seed row/column decided based on this criteria, the optimal basis dimension is computed. The proposed method effectively renders itself in the simultaneous estimation of the phase and the phase derivative. The proposed phase modeling approach also allows us to successfully demodulate the low density fringe patterns. Simulation and experimental results validate the practical applicability of the proposed method.

  11. 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.

  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. Probabilistic graphical models to deal with age estimation of living persons.

    PubMed

    Sironi, Emanuele; Gallidabino, Matteo; Weyermann, Céline; Taroni, Franco

    2016-03-01

    Due to the rise of criminal, civil and administrative judicial situations involving people lacking valid identity documents, age estimation of living persons has become an important operational procedure for numerous forensic and medicolegal services worldwide. The chronological age of a given person is generally estimated from the observed degree of maturity of some selected physical attributes by means of statistical methods. However, their application in the forensic framework suffers from some conceptual and practical drawbacks, as recently claimed in the specialised literature. The aim of this paper is therefore to offer an alternative solution for overcoming these limits, by reiterating the utility of a probabilistic Bayesian approach for age estimation. This approach allows one to deal in a transparent way with the uncertainty surrounding the age estimation process and to produce all the relevant information in the form of posterior probability distribution about the chronological age of the person under investigation. Furthermore, this probability distribution can also be used for evaluating in a coherent way the possibility that the examined individual is younger or older than a given legal age threshold having a particular legal interest. The main novelty introduced by this work is the development of a probabilistic graphical model, i.e. a Bayesian network, for dealing with the problem at hand. The use of this kind of probabilistic tool can significantly facilitate the application of the proposed methodology: examples are presented based on data related to the ossification status of the medial clavicular epiphysis. The reliability and the advantages of this probabilistic tool are presented and discussed.

  14. 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

  15. Leg stiffness in human running: Comparison of estimates derived from previously published models to direct kinematic-kinetic measures.

    PubMed

    Coleman, David R; Cannavan, Dale; Horne, Sara; Blazevich, Anthony J

    2012-07-26

    It is not presently clear whether mathematical models used to estimate leg stiffness during human running are valid. Therefore, leg stiffness during the braking phase of ground contact of running was calculated directly using synchronous kinematic (high-speed motion analysis) and kinetic (force platform) analysis, and compared to stiffness calculated using four previously published kinetic models. Nineteen well-trained male middle distance runners (age=21.1±4.1yr; VO(2max)=69.5±7.5mlO(2)kg(-1)min(-1)) completed a series of runs of increasing speed from 2.5 to 6.5ms(-1). Leg stiffness was calculated directly from kinetic-kinematic analysis using both vertical and horizontal forces to obtain the resultant force in the line of leg compression (Model 1). Values were also estimated using four previously published mathematical models where only force platform derived and anthropometric measures were required (Models 2-5; Morin et al., 2005, Morin et al., 2011, Blum et al., 2009, Farley et al., 1993, respectively). The greatest statistical similarity between leg stiffness values occurred with Models 1 and 2. The poorest similarity occurred when values from Model 4 were compared with Model 1. Analyses suggest that the poor correlation between Model 1 other models may have resulted from errors in the estimation in change in leg length during the braking phase. Previously published mathematical models did not provide accurate leg stiffness estimates, although Model 2, used by Morin et al. (2005), provided reasonable estimates that could be further improved by the removal of systematic error using a correction factor (K=1.0496K(Model2)).

  16. The influence of nonrandom extra‐pair paternity on heritability estimates derived from wild pedigrees

    PubMed Central

    Firth, Josh A.; Hadfield, Jarrod D.; Santure, Anna W.; Slate, Jon; Sheldon, Ben C.

    2015-01-01

    Quantitative genetic analysis is often fundamental for understanding evolutionary processes in wild populations. Avian populations provide a model system due to the relative ease of inferring relatedness among individuals through observation. However, extra‐pair paternity (EPP) creates erroneous links within the social pedigree. Previous work has suggested this causes minor underestimation of heritability if paternal misassignment is random and hence not influenced by the trait being studied. Nevertheless, much literature suggests numerous traits are associated with EPP and the accuracy of heritability estimates for such traits remains unexplored. We show analytically how nonrandom pedigree errors can influence heritability estimates. Then, combining empirical data from a large great tit (Parus major) pedigree with simulations, we assess how heritability estimates derived from social pedigrees change depending on the mode of the relationship between EPP and the focal trait. We show that the magnitude of the underestimation is typically small (<15%). Hence, our analyses suggest that quantitative genetic inference from pedigrees derived from observations of social relationships is relatively robust; our approach also provides a widely applicable method for assessing the consequences of nonrandom EPP. PMID:25800997

  17. 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

  18. 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.

  19. Age estimation from stages of epiphyseal union in the presacral vertebrae.

    PubMed

    Cardoso, Hugo F V; Ríos, Luis

    2011-02-01

    The presacral vertebrae have various secondary centers of ossification, whose timing of fusion can be used for age estimation of human skeletal remains up to the middle to the latter third decade. However, detailed information about the age at which these secondary centers of ossification fuse has been lacking. In this study, the timing of epiphyseal union in presacral vertebrae was studied in a sample of modern Portuguese skeletons (57 females and 47 males) between the ages of 9 and 30, taken from the Lisbon documented skeletal collection. A detailed photographic record of these epiphyses and the age ranges for the different stages of epiphyseal union are provided. Partial union of epiphyses was observed from 11 to 27 years of age. In general, centers of ossification begin to fuse first in the cervical and lumbar vertebrae, followed by centers of ossification in the thoracic region. The first center of ossification to complete fusion is usually that of the mammillary process in lumbar vertebrae. This is usually followed by that of the transverse process, spinous transverse process, and annular ring, regardless of vertebra type. There were no statistically significant sex differences in timing of fusion, but there was a trend toward early maturation in females for some vertebra or epiphyses. Bilateral epiphyses did not show statistically significant differences in timing of fusion. This study offers information on timing of fusion of diverse epiphyseal locations useful for age estimation of complete or fragmented human skeletal remains.

  20. 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

  1. Accuracy of the estimation of dental age in comparison with chronological age in a Spanish sample of 2641 living subjects using the Demirjian and Nolla methods.

    PubMed

    Melo, María; Ata-Ali, Javier

    2017-01-01

    Age estimation is an important procedure in forensic medicine and is carried out for a number of reasons. For living persons, age estimation is performed in order to assess whether a child has attained the age of criminal responsibility, in scenarios involving rape, kidnapping or marriage, in premature births, adoption procedures, illegal immigration, pediatric endocrine diseases and orthodontic malocclusion, as well as in circumstances in which the birth certificate is not available or the records are suspect. According to data from the UNHCR (United Nations High Commissioner for Refugees), the number of people seeking refugee status continued to increase in the last years, driven by the wars in Syria and Iraq, as well as by conflict and instability in Afghanistan, Eritrea and elsewhere. The objective of this study is to compare the accuracy of estimating dental age versus chronological age using the Nolla and Demirjian methods in a Spanish population. A final sample of 2641 panoramic X-rays corresponding to Spanish patients (1322 males and 1319 females) between 7-21 years of age was analyzed. Dental age was assessed using the Nolla and Demirjian methods, establishing comparisons with mean chronological age based on the Student t-test for paired samples, followed by the generation of a linear regression model. Both methods showed slight discrepancy between dental and chronological age. On examining the reproducibility of the Nolla and Demirjian methods, technical errors of 0.84% and 0.62%, respectively, were observed. On average, the Nolla method was found to estimate an age 0.213years younger than the chronological age, while the Demirjian method estimated an age 0.853years older than the chronological age. Linear combination of the mean Nolla and Demirjian estimates increased the predictive capacity to 99.2%. In conclusion the Nolla and Demirjian methods were found to be accurate in estimating chronological age from dental age in a Spanish population. The error

  2. Deriving age-specific incidence from prevalence with an ordinary differential equation.

    PubMed

    Brinks, Ralph; Landwehr, Sandra; Icks, Andrea; Koch, Michael; Giani, Guido

    2013-05-30

    This article describes new relationships between the age-specific incidence of, the prevalence of and mortality from a chronic disease. We express these relationships in terms of an ordinary differential equation and form the methodological basis for a novel approach to estimating incidences from age-specific prevalence data. We examine practical aspects of the relationships and a comparison with a known stochastic method in a simulation study. Finally, we apply the novel method to a data set of renal replacement therapy recorded from patients with chronic kidney failure in a region of Germany with approximately 310,000 inhabitants from 2002 to 2010.

  3. Applicability of Willems model for dental age estimations in Brazilian children.

    PubMed

    Franco, Ademir; Thevissen, Patrick; Fieuws, Steffen; Souza, Paulo Henrique Couto; Willems, Guy

    2013-09-10

    Several studies described tooth development as a reliable pathway for age estimations. Depending on the considered life span, the dental age indicators vary. In children, combinations of developing teeth provide the best information about age. In sub adults third molar mineralization is almost exclusively considered. The aim of this study was, firstly, to verify the Willems model in a Brazilian sample. Secondly, to observe differences between the Willems model and a new developed Brazilian model. Thirdly, the information of permanent teeth (PM) and third molar (TM), development was combined for age estimation in children. A sample of 1357 panoramic radiographs of Brazilian males (M) and females (F), with age between 5 and 23 years was collected. The technique of Gleiser and Hunt modified by Kohler (1955) [34] was applied for third molar staging in the entire sample. The Demirjian staging technique was used on the mandibular left permanent teeth (except third molars) of all individuals from 5 to 15 years. Kappa and weighted Kappa statistics were performed to verify inter- and intra-observer reliabilities. Based on the obtained Demirjian scores the Willems model was verified. Next the data were split to develop a new Brazilian model based on the Willems method and to verify the established model. The accuracy in age prediction between the Willems model and the new Brazilian model was compared. Additionally, regression models including PM, TM and PM plus TM information were compared. The Kappa and weighted Kappa statistics revealed high agreement between observers (0.88 Kappa; 0.93 weighted Kappa). The differences between predicted and chronological age for the verified Willems model were expressed in mean errors of -0.17 and -0.38 year for F and M respectively. The differences in mean error between the new developed Brazilian model and the Willems model were 0.02 (F) and 0.20 (M) year. The regression models combining PT and TM information provided only in the age

  4. Effects of Count Area Size on Model Ages Derived from Random CSFDs

    NASA Astrophysics Data System (ADS)

    van der Bogert, Carolyn; Michael, Gregory; Kneissl, Thomas; Hiesinger, Harald; Hendrik Pasckert, Jan

    2015-04-01

    As higher resolution imagery becomes available, smaller regions can be studied. These small areas, however, contain fewer craters for crater size-frequency distribution (CSFD) analysis. For example, a study of irregular mare patches (IMPs) on the Moon [1] could only measure craters, at three IMPs, that were large enough for derivation of absolute model ages (AMAs), using the current lunar chronology and production functions (CF/PF, valid for craters 10mages of IMPs have significant implications for lunar evolution, the robustness of the AMAs is important. In addition, young craters used to define the lunar chronology (e.g., North Ray [3] and Cone [4] craters) have small count areas of less than 1 km^2. While, Hiesinger et al. [3] show that ages derived from small areas are consistent with ages of larger areas, they exhibit variability greater than the statistical error bars [3,4]. Pasckert et al. [5] investigated whether 25 4 km2 count areas within a 100 km2 count area on mare basalt in Tsiolkovsky crater reproduce the age of the larger area. While 19 of the ages are within the error bars of the large area, six of the ages are not. However, the disparate ages could reflect local resurfacing events associated with later volcanism or impact cratering [5]. To eliminate the effects of local geologic activity such that we can evaluate the effects of count area size alone on the robustness of AMAs, we generated random crater distributions for theoretical lunar surfaces with ages of 0.1-4 Ga. We then analyzed the effects of decreasing count area size on the resulting AMAs. The precision of AMAs is determined by the Poisson cratering process and the non-linearity of the CF for the crater measurements themselves [6]. Smaller count areas have fewer craters, such that this statistical precision decreases. However, our study also shows that the accuracy of the AMAs is decreased for smaller count areas. For example, 4 km2 areas on 0.1 Ga

  5. Age estimation methods using anthropological parameters on human teeth-(A0736).

    PubMed

    Brkic, H; Milicevic, M; Petrovecki, M

    2006-10-16

    The research was conducted on the 160 intact extracted human teeth with one and two roots of the known age and sex. The teeth were disinfected, dried and X-rayed. After that the section of the longitudinal cut through the teeth was performed in order to facilitate monitoring of all tissues and morphological characteristics of the teeth. The age was determined in three ways: Method 1 [G.Bang, E. Ramm, Determination of age in humans from root dentin transparency, Acta Odontol. Scand. 28 (1970) 3-35]--analysis of the translucency of the root dentine, Method 2 [S. Kvaal, T. Solheim, A non-destructive dental method for age estimation, J. Forensic Odonto-stomatol. 12 (1994) 6-11]--analysis of the root and the root canal from the X-ray, Method 3 [G. Johanson, Age determination from human teeth, Odontol. Revy. 22 (1971) 1-126]--analysis of six parameters on each teeth. All data were subject to the correlation and regression analysis which showed the following: all of the three applied methods were in the significant correlation with the real age, and the best of them proved to be Method 3 where the coefficient of correlation was 0.85, p<0.001. The teeth of the maxilla are more convenient for the age determination than the teeth of mandible. They are in the significant strong correlation with the known real age, and in Method 3, the coefficient of correlation is 0.78, p<0.001. Age determination of the teeth with two roots is in significant correlation with the known real age p<0.001 in relation to the determined age on the teeth with one root. The results show that sex too, is in significant correlation with the real age, p<0.001. In practice, the methods used and the results achieved in this research have been enabling the dental age estimation of human remains from mass graves after the 1991 war in Croatia.

  6. 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

  7. Estimating allele age and selection coefficient from time-serial data.

    PubMed

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

    2012-10-01

    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.

  8. Motor cognitive processing speed estimation among the primary schoolchildren by deriving prediction formula: A cross-sectional study

    PubMed Central

    Aranha, Vencita Priyanka; Moitra, Monika; Saxena, Shikha; Narkeesh, Kanimozhi; Arumugam, Narkeesh; Samuel, Asir John

    2017-01-01

    Objectives: Motor cognitive processing speed (MCPS) is often reported in terms of reaction time. In spite of being a significant indicator of function, behavior, and performance, MCPS is rarely used in clinics and schools to identify kids with slowed motor cognitive processing. The reason behind this is the lack of availability of convenient formula to estimate MCPS. Thereby, the aim of this study is to estimate the MCPS in the primary schoolchildren. Materials and Methods: Two hundred and four primary schoolchildren, aged 6–12 years, were recruited by the cluster sampling method for this cross-sectional study. MCPS was estimated by the ruler drop method (RDM). By this method, a metallic stainless steel ruler was suspended vertically such that 5 cm graduation of the lower was aligned between the web space of the child's hand, and the child was asked to catch the moving ruler as quickly as possible, once released from the examiner's hand. Distance the ruler traveled was recorded and converted into time, which is the MCPS. Multiple regression analysis of variables was performed to determine the influence of independent variables on MCPS. Results: Mean MCPS of the entire sample of 204 primary schoolchildren is 230.01 ms ± 26.5 standard deviation (95% confidence interval; 226.4–233.7 ms) that ranged from 162.9 to 321.6 ms. By stepwise regression analysis, we derived the regression equation, MCPS (ms) = 279.625–5.495 × age, with 41.3% (R = 0.413) predictability and 17.1% (R2 = 0.171 and adjusted R2 = 0.166) variability. Conclusion: MCPS prediction formula through RDM in the primary schoolchildren has been established. PMID:28149087

  9. 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.

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

    PubMed

    Krauss, Lawrence M; Chaboyer, Brian

    2003-01-03

    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.

  11. Utility of the frontonasal suture for estimating age at death in human skeletal remains.

    PubMed

    Alesbury, Helen S; Ubelaker, Douglas H; Bernstein, Robin

    2013-01-01

    This project evaluated the utility of the frontonasal suture for estimating age at death. Utilizing human remains of known age at death with varying degrees of fusion, curated at the American Museum of Natural History in New York City and the Smithsonian Institution's National Museum of Natural History in Washington, DC, data were collected from the ectocranial surface of 522 crania; 68 of these were sagittally sectioned, allowing collection of internal data and observation of suture closure through the bone. Degree of ectocranial suture closure does not significantly predict age, even when sex and ancestry are accounted for. Suture closure progression data were converted into a Hershkovitz ratio (sum of the measurement of open portion divided by the total suture length), and regression models demonstrate that the effect of age accounts for only 13% of variation in suture closure.

  12. 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.

  13. 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.

  14. 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.

  15. Age and sex differences in estimated tibia strength: influence of measurement site.

    PubMed

    Sherk, Vanessa D; Bemben, Debra A

    2013-01-01

    Variability in peripheral quantitative computed tomography (pQCT) measurement sites and outcome variables limit direct comparisons of results between studies. Furthermore, it is unclear what estimates of bone strength are most indicative of changes due to aging, disease, or interventions. The purpose of this study was to examine age and sex differences in estimates of tibia strength. An additional purpose of this study was to determine which tibia site or sites are most sensitive for detecting age and sex differences in tibia strength. Self-identifying Caucasian men (n=55) and women (n=59) aged 20-59yr had their tibias measured with pQCT from 5% to 85% of limb length in 10% increments distal to proximal. Bone strength index, strength strain index (SSI), moments of inertia (Ip, Imax, and Imin), and strength-to-mass ratios (polar moment of inertia to total bone mineral content [BMC] ratio [Ip:Tot.BMC] and strength strain index to total BMC ratio [SSI:Tot.BMC]) were quantified. There were significant (p<0.01) site effects for all strength variables and strength-to-mass ratios. Site×sex interaction effects were significant (p<0.05) for all strength variables. Men had greater (p<0.01) values than women for all strength variables. Sex differences in Ip, Imax, Ip:Tot.BMC, SSI, and SSI:Tot.BMC ratios were the smallest at the 15% site and peaked at various sites, depending on variable. Site×age interactions existed for Imax, Ip:Tot.BMC, and SSI:Tot.BMC. There were significant age effects, Imax, Ip:Tot.BMC, and SSI:Tot.BMC, as values were the lowest in the 20-29 age group. Age and sex differences varied by measurement site and variable, and larger sex differences existed for moments of inertia than SSI. Strength-to-mass ratios may reflect efficiency of the whole bone architecture.

  16. 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

  17. 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.

  18. Neuroprotective and neurorestorative potential of propargylamine derivatives in ageing: focus on mitochondrial targets.

    PubMed

    Bar-Am, Orit; Amit, Tamar; Youdim, Moussa B; Weinreb, Orly

    2016-02-01

    The mitochondrial theory of ageing proposes that accumulation of damage to mitochondrial function and DNA mutation lead to ageing of humans and animals. It has been suggested that mitochondria play dynamic roles in regulating synaptogenesis and morphological/functional responses of synaptic activity, and thus, deteriorating of mitochondrial function (e.g., deficits of the mitochondrial respiratory enzymes, reduced calcium influx, increased accumulation of mitochondrial DNA defects/apoptotic proteins and impairment of mitochondrial membrane potential) can lead to severe neuronal energy deficit, and in the long run, to modifications in neuronal synapses and neurodegeneration in the ageing brain. Hence, considering the mechanisms by which mitochondrial impairment can lead to neuronal death, the development of neuroprotective molecules that target various mitochondrial pathogenic processes can be effective in the treatment of ageing and age-related neurodegenerative diseases. This review addresses several aspects of the neuroprotective effects of propargylamine derivatives (e.g., the monoamine oxidase-B inhibitors, selegiline and rasagiline and the multifunctional drugs, ladostigil, M30 and VAR10303) in ageing with a special focus on mitochondrial molecular protective mechanisms.

  19. Impaired phagocytosis of apoptotic cells causes accumulation of bone marrow-derived macrophages in aged mice

    PubMed Central

    Kim, Ok-Hee; Kim, Hyojung; Kang, Jinku; Yang, Dongki; Kang, Yu-Hoi; Lee, Dae Ho; Cheon, Gi Jeong; Park, Sang Chul; Oh, Byung-Chul

    2017-01-01

    Accumulation of tissue macrophages is a significant characteristic of disease-associated chronic inflammation, and facilitates the progression of disease pathology. However, the functional roles of these bone marrow-derived macrophages (BMDMs) in aging are unclear. Here, we identified age-dependent macrophage accumulation in the bone marrow, showing that aging significantly increases the number of M1 macrophages and impairs polarization of BMDMs. We found that age-related dysregulation of BMDMs is associated with abnormal overexpression of the anti-inflammatory interleukin-10. BMDM dysregulation in aging impairs the expression levels of pro-inflammatory cytokines and genes involved in B-cell maturation and activation. Phagocytosis of apoptotic Jurkat cells by BMDMs was reduced because of low expression of phagocytic receptor CD14, indicating that increased apoptotic cells may result from defective phagocytosis of apoptotic cells in the BM of aged mice. Therefore, CD14 may represent a promising target for preventing BMDM dysregulation, and macrophage accumulation may provide diagnostic and therapeutic clues. PMID:27866511

  20. 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.

  1. 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.

  2. Forensic age estimation by the Schmeling method: computed tomography analysis of the medial clavicular epiphysis.

    PubMed

    Ekizoglu, Oguzhan; Hocaoglu, Elif; Inci, Ercan; Sayin, Ibrahim; Solmaz, Dilek; Bilgili, Mustafa Gokhan; Can, Ismail Ozgur

    2015-01-01

    The variability of anthropometric measures, such as the degree of ossification, among societies should be taken into account when estimating age. The degree of ossification of the medial clavicle can be determined with thin-section computed tomography (CT), which is one of the methods recommended by the Study Group on Forensic Age Diagnostics of the German Association of Forensic Medicine. The purpose of this retrospective study was to investigate the applicability of thin-section CT analysis of the degree of ossification of the medial clavicle in a Turkish population. We evaluated the CT images (1-mm slice thickness) of 503 patients (362 male, 141 female; age, 10-35 years) using the Schmeling five-stage method. The Spearman's correlation analysis revealed a positive correlation between age and ossification stage in both male and female patients (total group: rho = 0.838, p < 0.001; male: rho = 0.831, p < 0.001; female: rho = 0.856, p < 0.001). The linear regression analysis results indicated that the ossification stage of the medial clavicle is a good predictor when estimating age (r (2) = 0.735 for all patients, 0.734 for male patients, 0.741 for female patients). Sex differences in ossification stages were observed only for stage 1 and 4 ossification. We believe that future research could expand the database on this topic and contribute to improvements in this measurement method.

  3. 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.

  4. 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.

  5. Geostatistical Model-Based Estimates of Schistosomiasis Prevalence among Individuals Aged ≤20 Years in West Africa

    PubMed Central

    Schur, Nadine; Hürlimann, Eveline; Garba, Amadou; Traoré, Mamadou S.; Ndir, Omar; Ratard, Raoult C.; Tchuem Tchuenté, Louis-Albert; Kristensen, Thomas K.; Utzinger, Jürg; Vounatsou, Penelope

    2011-01-01

    Background Schistosomiasis is a water-based disease that is believed to affect over 200 million people with an estimated 97% of the infections concentrated in Africa. However, these statistics are largely based on population re-adjusted data originally published by Utroska and colleagues more than 20 years ago. Hence, these estimates are outdated due to large-scale preventive chemotherapy programs, improved sanitation, water resources development and management, among other reasons. For planning, coordination, and evaluation of control activities, it is essential to possess reliable schistosomiasis prevalence maps. Methodology We analyzed survey data compiled on a newly established open-access global neglected tropical diseases database (i) to create smooth empirical prevalence maps for Schistosoma mansoni and S. haematobium for individuals aged ≤20 years in West Africa, including Cameroon, and (ii) to derive country-specific prevalence estimates. We used Bayesian geostatistical models based on environmental predictors to take into account potential clustering due to common spatially structured exposures. Prediction at unobserved locations was facilitated by joint kriging. Principal Findings Our models revealed that 50.8 million individuals aged ≤20 years in West Africa are infected with either S. mansoni, or S. haematobium, or both species concurrently. The country prevalence estimates ranged between 0.5% (The Gambia) and 37.1% (Liberia) for S. mansoni, and between 17.6% (The Gambia) and 51.6% (Sierra Leone) for S. haematobium. We observed that the combined prevalence for both schistosome species is two-fold lower in Gambia than previously reported, while we found an almost two-fold higher estimate for Liberia (58.3%) than reported before (30.0%). Our predictions are likely to overestimate overall country prevalence, since modeling was based on children and adolescents up to the age of 20 years who are at highest risk of infection. Conclusion/Significance We

  6. 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...

  7. 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.

  8. Global runoff estimates derived from GRACE dataset and in situ observations

    NASA Astrophysics Data System (ADS)

    Chandanpurkar, H. A.; Famiglietti, J. S.; Reager, J. T.; David, C. H.; Syed, T. H.

    2012-12-01

    Global in situ measurements of river discharge from streamflow gauge-stations are available with some consistency for the past several decades. However, the gauge-stations suffer from three major limitations: 1. Lack of regular maintenance and consequent data gaps; 2. Inadequate density of the gauge-stations in the delta regions at the continental margins; and 3. No representation of the sub-surface runoff. Since 2002, Gravity Recovery and Climate Experiment (GRACE) mission has been providing monthly datasets of terrestrial water storage anomaly that can be used to derive runoff values when combined with an atmospheric water balance reanalysis dataset during the last decade. In this research, we compare the GRACE dataset with the corresponding streamflow observations for the world's major river basins. Based on this comparison, we calculate a correction factor to the streamflow observations and estimate adjustment from various limitations on accuracy, from both the GRACE derived runoff estimates as well as those associated with the gauge-station observations, using Bayesian Model Averaging technique. The correction factor is assigned separately for major river basins. Then we apply these correction factors to the streamflow observations outside of the GRACE dataset to produce a gapless, extended time series of global river runoff providing the longevity of the streamflow observations and the improved accuracy due to the GRACE dataset.

  9. 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

  10. 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

  11. A cloned toy poodle produced from somatic cells derived from an aged female dog.

    PubMed

    Jang, G; Hong, S G; Oh, H J; Kim, M K; Park, J E; Kim, H J; Kim, D Y; Lee, B C

    2008-03-15

    To date, dogs have been cloned with somatic cell nuclear transfer (SCNT), using donor cells derived from large-breed dogs 2 months to 3 years of age. The objective of the present study was to use SCNT to produce a small-breed dog from ear fibroblasts of an aged poodle, using large-breed oocyte donors and surrogate females, and to determine the origin of its mitochondrial DNA (mtDNA) and the length of its telomeres. Oocytes were derived from large-breed donors, matured in vivo, collected by flushing oviducts, and reconstructed with somatic cells derived from an aged (14-year-old) female toy poodle. Oocytes and donor cells were fused by electric stimuli, activated chemically, and transferred into the oviducts of large-breed recipient females. Overall, 358 activated couplets were surgically transferred into the oviducts of 20 recipient dogs. Two recipients became pregnant; only one maintained pregnancy to term, and a live puppy (weighing 190 g) was delivered by Caesarean section. The cloned poodle was phenotypically and genetically identical to the nuclear donor dog; however, its mtDNA was from the oocyte donor, and its mean telomere length was not significantly different from that of the nuclear donor. In summary, we demonstrated that a small-breed dog could be cloned by transferring activated couplets produced by fusion of somatic cells from a small-breed, aged donor female with enucleated in-vivo-matured oocytes of large-breed females, and transferred into the oviduct of large-breed recipient female dogs.

  12. 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

  13. 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…

  14. 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

  15. 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

  16. 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.

  17. Reduced neuroplasticity in aged rats: a role for the neurotrophin brain-derived neurotrophic factor.

    PubMed

    Calabrese, Francesca; Guidotti, Gianluigi; Racagni, Giorgio; Riva, Marco A

    2013-12-01

    Aging is a physiological process characterized by a significant reduction of neuronal plasticity that might contribute to the functional defects observed in old subjects. Even if the neurobiological mechanisms that contribute to such impairment remain largely unknown, a role for neurotrophic molecules, such as the neurotrophin brain-derived neurotrophic factor (BDNF), has been postulated. On this basis, the purpose of this study was to provide a detailed investigation of the BDNF system, at transcriptional and translational levels, in the ventral and dorsal hippocampus and in the prefrontal cortex of middle-aged and old rats, compared with in adult animals. The expression of major players in BDNF regulation and response, including the transcription factors, calcium-responsive transcription factor, cyclic adenosine monophosphate (cAMP) responsive element-binding protein (CREB), and neuronal Per Arnt Sim (PAS) domain protein 4, and the high-affinity receptor tropomyosin receptor kinase B (TrkB), was also analyzed. Our results demonstrate that the BDNF system is affected at different levels in aged rats with global impairment including reduced transcription, impaired protein synthesis and processing, and decreased activation of the TrkB receptors. These modifications might contribute to the cognitive deficits associated with aging and suggest that pharmacological strategies aimed at restoring reduced neurotrophism might be useful to counteract age-related cognitive decline.

  18. 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

  19. 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.

  20. 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.

  1. Accuracy of developing tooth length as an estimate of age in human skeletal remains: the deciduous dentition.

    PubMed

    Cardoso, Hugo F V

    2007-10-02

    Dental age assessments are widely used to estimate age of immature skeletal remains. Most methods have relied on fractional stages of tooth emergence and formation, particularly of the permanent dentition, for predicting the age of infants and very young children. In this study, the accuracy of regression equations of developing deciduous tooth length for age estimation (Liversidge et al.) is tested on a sample of 30 Portuguese subadult skeletons of known age at death. Overall the method shows high accuracy and the average difference between estimated and chronological age is between 0.20 and -0.14 years when using single teeth, and 0.06 years, when using all available teeth. However, there is a tendency for the deciduous molars to provide overestimates of chronological age. Results show that age estimates can be obtained within +/-0.10 years with a 95% confidence interval when several teeth are used. Overall between-tooth agreement in age estimates decreases with increasing age but there is less variability of estimates with more teeth contributing to overall mean age. One seemingly limitation of this method may be the fact that it was developed by combining the maxillary and mandibular teeth. The other is related to the accuracy with which radiographic tooth length can be used as a valid surrogate for actual tooth length. Nevertheless, the advantages of this metric method surpass the limitations of chronologies based on stages of dental development.

  2. Aerodynamic derivatives for an oblique wing aircraft estimated from flight data by using a maximum likelihood technique

    NASA Technical Reports Server (NTRS)

    Maine, R. E.

    1978-01-01

    There are several practical problems in using current techniques with five degree of freedom equations to estimate the stability and control derivatives of oblique wing aircraft from flight data. A technique was developed to estimate these derivatives by separating the analysis of the longitudinal and lateral directional motion without neglecting cross coupling effects. Although previously applied to symmetrical aircraft, the technique was not expected to be adequate for oblique wing vehicles. The application of the technique to flight data from a remotely piloted oblique wing aircraft is described. The aircraft instrumentation and data processing were reviewed, with particular emphasis on the digital filtering of the data. A complete set of flight determined stability and control derivative estimates is presented and compared with predictions. The results demonstrated that the relatively simple approach developed was adequate to obtain high quality estimates of the aerodynamic derivatives of such aircraft.

  3. 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.

  4. Estimating the age of healthy infants from quantitative myelin water fraction maps.

    PubMed

    Dean, Douglas C; O'Muircheartaigh, Jonathan; Dirks, Holly; Waskiewicz, Nicole; Lehman, Katie; Walker, Lindsay; Piryatinsky, Irene; Deoni, Sean C L

    2015-04-01

    The trajectory of the developing brain is characterized by a sequence of complex, nonlinear patterns that occur at systematic stages of maturation. Although significant prior neuroimaging research has shed light on these patterns, the challenge of accurately characterizing brain maturation, and identifying areas of accelerated or delayed development, remains. Altered brain development, particularly during the earliest stages of life, is believed to be associated with many neurological and neuropsychiatric disorders. In this work, we develop a framework to construct voxel-wise estimates of brain age based on magnetic resonance imaging measures sensitive to myelin content. 198 myelin water fraction (VF(M) ) maps were acquired from healthy male and female infants and toddlers, 3 to 48 months of age, and used to train a sigmoidal-based maturational model. The validity of the approach was then established by testing the model on 129 different VF(M) datasets. Results revealed the approach to have high accuracy, with a mean absolute percent error of 13% in males and 14% in females, and high predictive ability, with correlation coefficients between estimated and true ages of 0.945 in males and 0.94 in females. This work represents a new approach toward mapping brain maturity, and may provide a more faithful staging of brain maturation in infants beyond chronological or gestation-corrected age, allowing earlier identification of atypical regional brain development.

  5. 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.

  6. Estimation of demographic measures for India, 1881-1961, based on census age distributions.

    PubMed

    Das Gupta, P

    1971-11-01

    Abstract India is one of the very few developing countries which have a relatively long history of population censuses. The first census was taken in 1872, the second in 1881 and since then there has been a census every ten years, the latest in 1971. Yet the registration of births and deaths in India, even at the present time, is too inadequate to be of much help in estimating fertility and mortality conditions in the country. From time to time Indian census actuaries have indirectly constructed life tables by comparing one census age distribution with the preceding one. Official life tables are available for all the decades from 1872-1881 to 1951-1961, except for 1911-1921 and 1931-1941. Kingsley Davis(1) filled in the gap by constructing life tables for the latter two decades. He also estimated the birth and death rates ofIndia for the decades from 1881-1891 to 1931-1941. Estimates of these rates for the following two decades, 1941-1951 and 1951-1961, were made by Indian census actuaries. The birth rates of Davis and the Indian actuaries were obtained basically by the reverse survival method from the age distribution and the computed life table of the population. Coale and Hoover(2), however, estimated the birth and death rates and the life table of the Indian population in 1951 by applying stable population theory. The most recent estimates of the birth rate and death rate for 1963-1964 are based on the results of the National Sample Survey. All these estimates are presented in summary form in Table 1.

  7. L-carnitine significantly decreased aging of rat adipose tissue-derived mesenchymal stem cells.

    PubMed

    Mobarak, Halimeh; Fathi, Ezzatollah; Farahzadi, Raheleh; Zarghami, Nosratollah; Javanmardi, Sara

    2017-03-01

    Mesenchymal stem cells are undifferentiated cells that have the ability to divide continuously and tissue regeneration potential during the transplantation. Aging and loss of cell survival, is one of the main problems in cell therapy. Since the production of free radicals in the aging process is effective, the use of antioxidant compounds can help in scavenging free radicals and prevent the aging of cells. The aim of this study is evaluate the effects of L-carnitine (LC) on proliferation and aging of rat adipose tissue-derived mesenchymal stem cells (rADSC). rADSCs were isolated from inguinal region of 5 male Rattus rats. Oil red-O, alizarin red-S and toluidine blue staining were performed to evaluate the adipogenic, osteogenic and chondrogenic differentiation of rADSCs, respectively. Flow cytometric analysis was done for investigating the cell surface markers. The methyl thiazol tetrazolium (MTT) method was used to determine the cell proliferation of rADSCs following exposure to different concentrations of LC. rADSCs aging was evaluated by beta-galactosidase staining. The results showed significant proliferation of rADSCs 48 h after treatment with concentrations of 0.2 mM LC. In addition, in the presence of 0.2 mM LC, rADSCs appeared to be growing faster than control group and 0.2 mM LC supplementation could significantly decrease the population doubling time and aging of rADSCs. It seems that LC would be a good antioxidant to improve lifespan of rADSCs due to the decrease in aging.

  8. 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.

  9. 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

  10. Magnetic resonance imaging of distal tibia and calcaneus for forensic age estimation in living individuals.

    PubMed

    Ekizoglu, Oguzhan; Hocaoglu, Elif; Can, Ismail Ozgur; Inci, Ercan; Aksoy, Sema; Bilgili, Mustafa Gokhan

    2015-07-01

    In recent years, methods by which to decrease radiation exposure during age estimation have gained importance and become a main research area in the forensic sciences. Imaging tools such as X-ray and computed tomography (CT) are accepted as the main diagnostic methods for evaluation of the epiphysis in living individuals; however, radiation exposure and superimposition are the main disadvantages of these techniques. Magnetic resonance (MR) imaging provides an advantage in terms of preventing radiation exposure. In this study, we performed an MR analysis of the degree of fusion of the distal tibia and calcaneal epiphysis and investigated the utility of this technique in the Turkish population. Using the three-stage method described by Saint-Martin et al., we retrospectively evaluated 167 MR images (97 males, 70 females; mean age, 17.7 ± 4.8 years for males and 17.6 ± 4.9 years for females; age range of all subjects, 8-25 years). Intraobserver and interobserver evaluation showed good repeatability and consistency of this method. Stages 2 and 3 ossification of the distal tibial epiphysis first occurred at age 14 and 15 years in males and 12 and 14 years in females, respectively. Stages 2 and 3 ossification of the calcaneal epiphysis first occurred at age 14 and 16 years in males and 10 and 12 years in females, respectively. When performed alone, MR analysis of the distal tibial and calcaneal epiphysis offers limited information for forensic age estimation. However, we suggest that MR analysis can be used as a supportive method when it is necessary to avoid repeated radiation exposure.

  11. A Bayesian Approach to Age-at-Death Estimation from Osteoarthritis of the Shoulder in Modern North Americans.

    PubMed

    Brennaman, Ashley L; Love, Kim R; Bethard, Jonathan D; Pokines, James T

    2016-12-08

    Osteoarthritis (OA) is a marker of degeneration within the skeleton, frequently associated with age. This study quantifies the correlation between OA and age-at-death and investigates the utility of shoulder OA as a forensic age indicator using a modern North American sample of 206 individuals. Lipping, surface porosity, osteophyte formation, eburnation, and percentage of joint surface affected were recorded on an ordinal scale and summed to create composite scores that were assigned a specific phase. Spearman's correlation indicated a positive relationship between each composite score and age (right shoulder = 0.752; left shoulder = 0.734). Transition analysis revealed a tendency toward earlier degeneration of the right shoulder. Bayesian statistics generated phase-related age estimates based on highest posterior density regions. Best age estimates were into the seventh decade at the 90th and 50th percentile. The proposed method supplements traditional techniques by providing age estimates beyond a homogenous 50+ age cohort.

  12. Calliphora vicina (Diptera: Calliphoridae) pupae: a timeline of external morphological development and a new age and PMI estimation tool.

    PubMed

    Brown, Katherine; Thorne, Alan; Harvey, Michelle

    2015-07-01

    The minimum postmortem interval (PMI(min)) is commonly estimated using calliphorid larvae, for which there are established age estimation methods based on morphological and development data. Despite the increased duration and sedentary nature of the pupal stage of the blowfly, morphological age estimation methods are poorly documented and infrequently used for PMI determination. The aim of this study was to develop a timeline of metamorphosis, focusing on the development of external morphology (within the puparium), to provide a means of age and PMI estimation for Calliphora vicina (Rob-Desvoidy) pupae. Under controlled conditions, 1,494 pupae were reared and sampled at regular time intervals. After puparium removal, observations of 23 external metamorphic developments were correlated to age in accumulated degree hours (ADH). Two age estimation methods were developed based on (1) the combination of possible age ranges observed for each characteristic and (2) regression analyses to generate age estimation equations employing all 23 characteristics observed and a subset of ten characteristics most significantly correlated with age. Blind sample analysis indicated that, using the combination of both methods, pupal age could be estimated to within ±500 ADH with 95% reliability.

  13. 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.

  14. 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

  15. Use of maxillary tooth development to estimate age in a group of Hereford cross Friesian steers.

    PubMed

    Andrews, A H

    1981-11-01

    Visual and radiographic examination of maxillary tooth development was undertaken in a group of 76 Hereford cross Friesian steers, all but one slaughtered at the same weight (464 kg). Differences were found in the stages of second molar intraoral development between the various age groups. Radiographic inspection showed that stages of resorption of the temporary premolar roots and crown and root formation of the permanent cheek teeth varied with age. The maximum age range before animals could be differentiated into age groups using radiographic examination of maxillary tooth development was three months (one year from one year three months, one year three months from one year six months, one year four months from one year seven months, one year five months from one year eight months). In the carcase, radiography of the maxillary teeth provided a useful estimate of age. The first two maxillary molars were more advanced in crown and root formation than the permanent premolars. Except for the second permanent premolar all maxillary teeth were less advanced in development than their mandibular counterparts.

  16. Protein intake and urinary excretion of protein-derived metabolites in aging female vegetarians and nonvegetarians.

    PubMed

    Kunkel, M E; Beauchene, R E

    1991-08-01

    Relationships among age, protein intake, and urinary excretion of protein-derived metabolites were studied in 125 vegetarian and nonvegetarian women ages 40-92. There were 63 women in the vegetarian (AV) group and 62 women in the nonvegetarian (NV) group. Average daily intakes of energy and total animal and vegetable protein were calculated from 7-day dietary records. Twenty-four-hour urine samples were analyzed for total nitrogen, urea, creatinine, hydroxyproline, and inorganic sulfate. Energy intakes for the two groups were similar. AVs consumed less total and animal protein and more vegetable protein than NVs, even though both groups consumed more than the RDA for protein. No significant differences existed between the groups in the urinary excretion of total nitrogen, urea nitrogen, hydroxyproline, or inorganic sulfate. Energy and protein intakes and total nitrogen excretion were lower in older AVs than in younger AVs, while those of NVs increased between 40 and 55 years of age, and decreased among the older NV women. The relationship between these variables and age in NVs was more accurately described by polynomial rather than linear regression models.

  17. Composite estimates of physiological stress, age, and diabetes in American Samoans.

    PubMed

    Crews, Douglas E

    2007-07-01

    Composite estimates of physiological stress such as allostatic load (AL) were developed to help assess cumulative impacts of psychosocial and physical stressors on the body. Physiological responses to stress generally accelerate somatic wear-and-tear and chronic degenerative conditions (CDCs). Following McEwen (Neuropsychopharmacology 22 (1999) 108-124) and others, primary physiological mediators of somatic stress responses include glucocorticoids (cortisol), catecholamines (adrenaline and noradrenaline), and serum dihydroepiandosterone-sulfate (DHEA-S). Conversely, blood pressure (BP), serum HDL and total cholesterol, glycated hemoglobin (HbA1c), and waist/hip (w/h) ratio are modulated by such hormones, thereby acting as secondary mediators of stress response. When these risk factors are aggregated into a composite score, higher stress loads are associated with increased risks for days of school/work missed, functional losses, morbidity, and mortality in US samples. To examine stress loads in American Samoans, data on all 6 secondary mediators along with estimates of body habitus (i.e. height, weight, circumferences, skinfolds) and physiology (i.e. fasting insulin, LDLc, triglycerides, fasting glucose) were measured on 273 individuals residing on Tutuila Island in 1992. Four combinations of these physiological factors were used to determine composite estimates of stress. These were then assessed by sex for associations with age and the presence of diabetes. Composite estimates of stress load were higher in Samoan women than men. Associations with age tended to be low and negative in men, but positive in women, appearing to reflect cultural circumstances and population history. Stress load scores also were higher among those with diabetes than those without among both men and women. These results suggest that composite estimates of stress may be useful for assessing future risks of CDC's and the senescent processes that may underlie them in cross-cultural research.

  18. Derivation and validation of a novel Semi Empirical Deposition Estimation Model (SEDEM).

    PubMed

    Koivurova, Matias; Leppänen, Ari-Pekka

    2016-12-01

    Predictive models are necessary in order to minimize potential damages in the event of a nuclear or radiological release. For this reason, a novel model for the calculation of both wet and dry deposition from airborne radioactivity is proposed. Full derivation of the model and the estimation of uncertainty are presented, and the validity of the model is evaluated by calculating deposition based on several measured airborne activities in different countries. The results are compared with the corresponding measured deposition activities and the predictive power of the model is found to be good, i.e. calculated depositions being within the limits of measurement uncertainty. Additionally, limitations of the model and possible sources of error in the calculations are discussed.

  19. 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.

  20. The Risser sign for forensic age estimation in living individuals: a study of 643 pelvic radiographs.

    PubMed

    Wittschieber, Daniel; Schmeling, Andreas; Schmidt, Sven; Heindel, Walter; Pfeiffer, Heidi; Vieth, Volker

    2013-03-01

    Due to increasing international migratory movements, forensic age estimations of living individuals in criminal proceedings are gaining increasing significance for forensic physicians and radiologists involved in delivering expert opinions. The present study examines the suitability of the radiologically well-known Risser sign grading as a possible new criterion in forensic age diagnostics. For this purpose, anteroposterior pelvic radiographs of 643 patients aged between 10 and 30 years were retrospectively evaluated by means of two different Risser sign grading systems (US and French), each with 5 stages. The left and right sides of the pelvis were assessed separately. The data was analyzed with separation of the sexes. Reliable Risser sign determination was possible in 566 cases. In both sexes, stage 4 of both the US and the French grading systems was predominantly first noted at age 14 years. In the US grading system, stage 5 was also first achieved at age 14 years in the majority of both sexes. In the French grading system, females manifested stage 5 at a minimum of 16 years, whereas in males it was first observed at 17 years. As to the nature of iliac crest maturation, interesting deviations were observed at stages 1 and 5, raising doubts about Risser's ossification process. To conclude, both Risser sign grading systems are suitable for forensic age diagnostics, especially to determine whether the 14th year of life has been completed or not. The French Risser sign system additionally allows for statements as to the completion of the 16th year of age.

  1. 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

  2. Women Under-estimate the Age of their Partners during Survey Interviews: Implications for HIV Risk associated with Age Mixing in Northern Malawi

    PubMed Central

    Kohler, Hans-Peter; Mkandawire, James

    2011-01-01

    Background Age mixing may explain differences in HIV prevalence across populations in sub-Saharan countries, but the validity of survey data on age mixing is unknown. Methods Age differences between partners are frequently estimated indirectly, by asking respondents to report their partner’s age. Partner age can also be assessed directly, by tracing partners and asking them to report their own age. We use data from 519 relationships, collected in Likoma (Malawi), in which both partners were interviewed and tested for HIV. In these relationships age differences were assessed both indirectly and directly, and estimates could thus be compared. We calculate the specificity and sensitivity of the indirect method in identifying age-homogenous/age-disparate relationships in which the male partner is less/more than 5 or 10 years older than the respondent. Results Women were accurate in identifying age-homogenous relationships, but not in identifying age-disparate relationships (specificity ≈ 90%, sensitivity = 24.3%). The sensitivity of the indirect method was even lower in detecting partners older than the respondent by 10 + years (9.6%). Among 43 relationships with an HIV-infected partner included in this study, there were close to 3 times more age-disparate relationships according to direct measures of partner age than according to women’s reports of their partner’s age (17% vs. 46%). Conclusions Survey reports of partner age significantly under-estimate the extent of and the HIV risk associated with age mixing in this population. Future studies of the impact of sexual mixing pattern son HIV risk in sub-Saharan countries should take reporting biases into account. PMID:21992979

  3. Estimating the Ages of Selection Signals from Different Epochs in Human History

    PubMed Central

    Nakagome, Shigeki; Alkorta-Aranburu, Gorka; Amato, Roberto; Howie, Bryan; Peter, Benjamin M.; Hudson, Richard R.; Di Rienzo, Anna

    2016-01-01

    Genetic variation harbors signatures of natural selection driven by selective pressures that are often unknown. Estimating the ages of selection signals may allow reconstructing the history of environmental changes that shaped human phenotypes and diseases. We have developed an approximate Bayesian computation (ABC) approach to estimate allele ages under a model of selection on new mutations and under demographic models appropriate for human populations. We have applied it to two resequencing data sets: An ultra-high depth data set from a relatively small sample of unrelated individuals and a lower depth data set in a larger sample with transmission information. In addition to evaluating the accuracy of our method based on simulations, for each SNP, we assessed the consistency between the posterior probabilities estimated by the ABC approach and the ancient DNA record, finding good agreement between the two types of data and methods. Applying this ABC approach to data for eight single nucleotide polymorphisms (SNPs), we were able to rule out an onset of selection prior to the dispersal out-of-Africa for three of them and more recent than the spread of agriculture for an additional three SNPs. PMID:26545921

  4. The role of forensic medicine and forensic dentistry in estimating the chronological age of living individuals in Hamburg, Germany.

    PubMed

    Mansour, Hussam; Fuhrmann, Andreas; Paradowski, Ioana; van Well, Eilin Jopp; Püschel, Klaus

    2017-03-01

    Age estimation represents one of the primary responsibilities of forensic medicine and forensic dentistry. It is an integral procedure aiming to estimate the chronological age of an individual, whose age is either unknown or doubtful, by means of assessing the stage of dental, skeletal, and physical development. The present publication reviews the methods and procedures used in estimating the age of young living individuals as well as the experiences of the Institute of Legal Medicine in Hamburg-Eppendorf, Germany, during the last 25 years. From 1990 to 2015, 4223 age estimations were carried out in Hamburg. During this time, forensic age estimation was requested by different concerned authorities including courts, the foreigners' registration office (Zentrale Ausländerbehörde), and the state office of education and consultation (Landesbetrieb Erziehung und Beratung). In the context of judicial proceedings, orthopantomograms, as well as X-ray examinations of both the left hand and the medial clavicular epiphyses were carried out in accordance with AGFAD recommendations. For investigations not associated with judicial proceedings, orthopantomogram examinations play a key role in the process of age estimation, due to their high diagnostic value and low radiation exposure. Since 2009, mainly unaccompanied young refugees were examined for age estimation. Orthopantomograms and clinical-physical examinations have been used as essential steps in this context to determine whether an individual is 18 years or less. Additional X-ray examinations of the left hand and the medial clavicular epiphyses have been used less frequently.

  5. 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

  6. 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.

  7. Estimation of paleotemperature from racemization of aspartic acid in combination with radiocarbon age

    NASA Astrophysics Data System (ADS)

    Minami, Masayo; Takeyama, Masami; Mimura, Koichi; Nakamura, Toshio

    2007-06-01

    We tried to estimate paleotemperatures from two chosen fossils by measuring D/L aspartic acid ratios and radiocarbon ages of the XAD-2-treated hydrolysate fractions in the fossils. The D/L aspartic acid ratio was measured with a gas chromatograph and radiocarbon dating was performed using a Tandetron AMS system at Nagoya University. The radiocarbon age of a fossil mammoth molar collected from Bykovsky Peninsula, eastern Siberia, was found to be 35,170 ± 300 BP as an average value for the XAD-treated hydrolysate fractions. The aspartic acid in the mammoth molar showed a little evidence of racemization, which might be due to in vivo racemization during the lifetime and then suggests negligible or no postmortem racemization during burial in permafrost. From four animal bone fossils collected from a shell mound excavated at the Awazu submarine archeological site in Lake Biwa, Shiga, Japan, the racemization-based effective mean temperature was calculated to be 15-16 °C using the D/L aspartic acid ratio of about 0.11 and the 14C age of 4500 BP for the XAD-2-treated hydrolysate fractions in the fossils. The average annual temperature was estimated to be 11-12 °C, which approximates to the temperature that the fossils experienced during burial at the site. Although the application of racemization ratios in fossils as paleotemperature indicators is surrounded with many difficulties, the results obtained in this study suggest its feasibility.

  8. Estimating the age of fire in the Cape flora of South Africa from an orchid phylogeny.

    PubMed

    Bytebier, Benny; Antonelli, Alexandre; Bellstedt, Dirk U; Linder, H Peter

    2011-01-22

    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.

  9. Estimating Modifying Effect of Age on Genetic and Environmental Variance Components in Twin Models

    PubMed Central

    He, Liang; Sillanpää, Mikko J.; Silventoinen, Karri; Kaprio, Jaakko; Pitkäniemi, Janne

    2016-01-01

    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 parametric G × E interaction 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

  10. TEMPERATURE AND DENSITY ESTIMATES OF EXTREME-ULTRAVIOLET FLARE RIBBONS DERIVED FROM TRACE DIFFRACTION PATTERNS

    SciTech Connect

    Krucker, Saem; Raftery, Claire L.; Hudson, Hugh S.

    2011-06-10

    We report on Transition Region And Coronal Explorer 171 A observations of the GOES X20 class flare on 2001 April 2 that shows EUV flare ribbons with intense diffraction patterns. Between the 11th to 14th order, the diffraction patterns of the compact flare ribbon are dispersed into two sources. The two sources are identified as emission from the Fe IX line at 171.1 A and the combined emission from Fe X lines at 174.5, 175.3, and 177.2 A. The prominent emission of the Fe IX line indicates that the EUV-emitting ribbon has a strong temperature component near the lower end of the 171 A temperature response ({approx}0.6-1.5 MK). Fitting the observation with an isothermal model, the derived temperature is around 0.65 MK. However, the low sensitivity of the 171 A filter to high-temperature plasma does not provide estimates of the emission measure for temperatures above {approx}1.5 MK. Using the derived temperature of 0.65 MK, the observed 171 A flux gives a density of the EUV ribbon of 3 x 10{sup 11} cm{sup -3}. This density is much lower than the density of the hard X-ray producing region ({approx}10{sup 13} to 10{sup 14} cm{sup -3}) suggesting that the EUV sources, though closely related spatially, lie at higher altitudes.

  11. Temperature and Density Estimates of Extreme-ultraviolet Flare Ribbons Derived from TRACE Diffraction Patterns

    NASA Astrophysics Data System (ADS)

    Krucker, Säm; Raftery, Claire L.; Hudson, Hugh S.

    2011-06-01

    We report on Transition Region And Coronal Explorer 171 Å observations of the GOES X20 class flare on 2001 April 2 that shows EUV flare ribbons with intense diffraction patterns. Between the 11th to 14th order, the diffraction patterns of the compact flare ribbon are dispersed into two sources. The two sources are identified as emission from the Fe IX line at 171.1 Å and the combined emission from Fe X lines at 174.5, 175.3, and 177.2 Å. The prominent emission of the Fe IX line indicates that the EUV-emitting ribbon has a strong temperature component near the lower end of the 171 Å temperature response (~0.6-1.5 MK). Fitting the observation with an isothermal model, the derived temperature is around 0.65 MK. However, the low sensitivity of the 171 Å filter to high-temperature plasma does not provide estimates of the emission measure for temperatures above ~1.5 MK. Using the derived temperature of 0.65 MK, the observed 171 Å flux gives a density of the EUV ribbon of 3 × 1011 cm-3. This density is much lower than the density of the hard X-ray producing region (~1013 to 1014 cm-3) suggesting that the EUV sources, though closely related spatially, lie at higher altitudes.

  12. 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

  13. Combining Hf-W Ages, Cooling Rates, and Thermal Models to Estimate the Accretion Time of Iron Meteorite Parent Bodies

    NASA Astrophysics Data System (ADS)

    Qin, L.; Dauphas, N.; Wadhwa, M.; Masarik, J.; Janney, P. E.

    2007-12-01

    The 182Hf-182W short-lived chronometer has been widely used to date metal-silicate differentiation processes in the early Solar System. However the presence of cosmogenic effects from exposure to GCR can potentially hamper the use of this system for chronology purposes (e.g. [1,2]). These effects must be corrected for in order to calculate metal-silicate differentiation ages. In this study, high-precision W isotope measurements are presented for 32 iron meteorites from 8 magmatic and 2 non-magmatic groups. Exposure ages and pre- atmospheric size estimates are available for most of these samples [3]. Our precision is better than or comparable to the currently most precise literature data and our results agree with previous work [4]. All magmatic irons have ɛ182W equal within error to or more negative than the Solar System initial derived from a CAI isochron [5]. Iron meteorites from the same magmatic groups show variations in ɛ182W. These are most easily explained by exposure to cosmic rays in space. A correction method was developed to estimate pre-exposure ɛ182W for individual iron meteorite groups. Metal-silicate differentiation in most iron meteorite parent bodies must have occurred within 2 Myr of formation of refractory inclusions. For the first time, we combine 182Hf-182W ages with parent body sizes inferred from metallographic cooling rates in a thermal model to constrain the accretion time of iron meteorite parent bodies. The estimated accretion ages are within 1.5 Myr for most magmatic groups, and could be as early as 0.2 Myr after CAI formation. This is consistent with the study of Bottke et al. [6] who argued that iron meteorite parent bodies could represent an early generation of planetesimals formed in the inner region of the Solar System. [1] Masarik J. (1997) EPSL 152, 181-185. [2] Markowski A. et al. (2006) EPSL 250,104-115. [3] Voshage H. (1984) EPSL 71, 181-194. [4] Markowski A. et al. (2006) EPSL 242, 1-15. [5] Kleine T. et al. (2005) GCA 69

  14. Model based period analysis of absolute and relative survival with R: data preparation, model fitting and derivation of survival estimates.

    PubMed

    Holleczek, Bernd; Brenner, Hermann

    2013-05-01

    Period analysis is increasingly employed in analyses of long-term survival of patients with chronic diseases such as cancer, as it derives more up-to-date survival estimates than traditional cohort based approaches. It has recently been extended with regression modelling using generalized linear models, which increases the precision of the survival estimates and enables to assess and account for effects of additional covariates. This paper provides a detailed presentation how model based period analysis may be used to derive population-based absolute and relative survival estimates using the freely available R language and statistical environment and already available R programs for period analysis. After an introduction of the underlying regression model and a description of the software tools we provide a step-by-step implementation of two regression models in R and illustrate how estimates and a test for trend over time in relative survival may be derived using data from a population based cancer registry.

  15. 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

  16. Ra isotopes in trees: Their application to the estimation of heartwood growth rates and tree ages

    NASA Astrophysics Data System (ADS)

    Hancock, Gary J.; Murray, Andrew S.; Brunskill, Gregg J.; Argent, Robert M.

    2006-12-01

    The difficulty in estimating growth rates and ages of tropical and warm-temperate tree species is well known. However, this information has many important environmental applications, including the proper management of native forests and calculating uptake and release of atmospheric carbon. We report the activities of Ra isotopes in the heartwood, sapwood and leaves of six tree species, and use the radial distribution of the 228Ra/226Ra activity ratio in the stem of the tree to estimate the rate of accretion of heartwood. A model is presented in which dissolved Ra in groundwater is taken up by tree roots, translocated to sapwood in a chemically mobile (ion-exchangeable) form, and rendered immobile as it is transferred to heartwood. Uptake of 232Th and 230Th (the parents of 228Ra and 226Ra) is negligible. The rate of heartwood accretion is determined from the radioactive decay of 228Ra (half-life 5.8 years) relative to long-lived 226Ra (half-life 1600 years), and is relevant to growth periods of up to 50 years. By extrapolating the heartwood accretion rate to the entire tree ring record the method also appears to provide realistic estimates of tree age. Eight trees were studied (three of known age, 72, 66 and 35 years), including three Australian hardwood eucalypt species, two mangrove species, and a softwood pine (P. radiata). The method indicates that the rate of growth ring formation is species and climate dependent, varying from 0.7 rings yr-1 for a river red gum (E. camaldulensis) to around 3 rings yr-1 for a tropical mangrove (X. mekongensis).

  17. 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 predicted 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.

  18. Thermal aging of cast stainless steels in LWR systems: Estimation of mechanical properties

    SciTech Connect

    Chopra, O.K.

    1991-11-01

    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.

  19. Thermal aging of cast stainless steels in LWR systems: Estimation of mechanical properties

    SciTech Connect

    Chopra, O.K.

    1991-11-01

    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.

  20. Estimating conception statistics using gestational age information from NHS Numbers for Babies data.

    PubMed

    Chow, Yuan Huang; Dattani, Nirupa

    2009-01-01

    Conception statistics routinely published for England and Wales include pregnancies that result in one or more live- or stillbirths (a maternity) or an abortion. All live births are assumed to be 38 weeks gestation as information on gestation is not collected at birth registration. For the first time, gestational age information from the National Health Service (NHS) Numbers for Babies (NN4B) data has been used to re-estimate conception statistics for 2005. This shows that 72 per cent of conceptions leading to a maternity in fact have a gestati on period that differs from 38 weeks and most of these fall at either 37 or 39 weeks. The age-specific conception rates using this revised method are not significantly different to those produced using the current method.

  1. The research on aging failure rate and optimization estimation of protective relay under haze conditions

    NASA Astrophysics Data System (ADS)

    Wang, Ying-kang; Zhou, Meng-ran; Yang, Jie; Zhou, Pei-qiang; Xie, Ying

    2017-01-01

    In the fog and haze, the air contains large amounts of H2S, SO2, SO3 and other acids, air conductivity is greatly improved, the relative humidity is also greatly increased, Power transmission lines and electrical equipment in such an environment will increase in the long-running failure ratedecrease the sensitivity of the detection equipment, impact protection device reliability. Weibull distribution is widely used in component failure distribution fitting. It proposes a protection device aging failure rate estimation method based on the least squares method and the iterative method,.Combined with a regional power grid statistics, computing protective equipment failure rate function. Binding characteristics of electrical equipment operation status under haze conditions, optimization methods, get more in line with aging protection equipment failure under conditions of haze characteristics.

  2. 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

  3. 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.

  4. 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.

  5. How old are you? Genet age estimates in a clonal animal.

    PubMed

    Devlin-Durante, M K; Miller, M W; Precht, W F; Baums, I B

    2016-11-01

    Foundation species such as redwoods, seagrasses and corals are often long-lived and clonal. Genets may consist of hundreds of members (ramets) and originated hundreds to thousands of years ago. As climate change and other stressors exert selection pressure on species, the demography of populations changes. Yet, because size does not indicate age in clonal organisms, demographic models are missing data necessary to predict the resilience of many foundation species. Here, we correlate somatic mutations with genet age of corals and provide the first, preliminary estimates of genet age in a colonial animal. We observed somatic mutations at five microsatellite loci in rangewide samples of the endangered coral, Acropora palmata (n = 3352). Colonies harboured 342 unique mutations in 147 genets. Genet age ranged from 30 to 838 years assuming a mutation rate of 1.195(-04) per locus per year based on colony growth rates and 236 to 6500 years assuming a mutation rate of 1.542(-05) per locus per year based on sea level changes to habitat availability. Long-lived A. palmata genets imply a large capacity to tolerate past environmental change, and yet recent mass mortality events in A. palmata suggest that capacity is now being frequently exceeded.

  6. 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.

  7. 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.

  8. Rapid, cost-effective estimation of groundwater age based on hydrochemistry

    NASA Astrophysics Data System (ADS)

    Beyer, M.; Morgenstern, U.; Jackson, B. M.; Daughney, C.

    2013-12-01

    aquifer. This relation can then be used in the same or similar aquifer to infer groundwater age from given hydrochemistry. Secondly specific reaction rates of underlying reactions, such as quartz dissolution, can be determined and used to determine specific and ';generic' reaction rates for field environments. We postulate this may in future lead to groundwater dating directly from specific hydrochemistry data in any given aquifer by using ';generic' kinetics. To illustrate these two approaches, regularly measured hydrochemistry data and estimates of groundwater age inferred from tritium, SF6 and CFC-12 within the Lower Hutt Groundwater Zone, a gravel aquifer in Wellington, New Zealand, are used. Correlations of hydrochemistry parameters and groundwater age are presented. Hierarchical Cluster and Factor Analysis are used to investigate major processes which caused the given hydrochemistry. Inverse modelling is used to identify specific underlying reactions, such as weathering of quartz. Reaction kinetics are investigated and results presented.

  9. It takes nine days to iron a shirt: the development of cognitive estimation skills in school age children.

    PubMed

    Harel, Brian T; Cillessen, Antonius H N; Fein, Deborah A; Bullard, Sarah E; Aviv, Alyson

    2007-07-01

    Data are presented for 315 elementary school-aged children (K-11) who took the Biber Cognitive Estimation Test, a 20-item test with five estimation questions in each of four domains: quantity, time/duration, weight, and distance/length. Performance showed significant development yearly until around the age of nine years, with much slower development subsequently. No gender effects were found. Age and fund of knowledge correlated with overall test performance. Fund of information accounted for a large proportion of the variance in estimation skills for children 8 years and under, but not for children 9 years and older. Since estimation skills require retrieval and manipulation of relevant knowledge and inhibition of impulsive responding and are necessary in many everyday tasks, it was anticipated that this test may provide a useful measure of judgment and estimations and may correlate with other executive skills in school-aged children.

  10. 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

  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. Analysis of age-at-death estimation using data from a new, modern autopsy sample--part I: pubic bone.

    PubMed

    Hartnett, Kristen M

    2010-09-01

    This research tests the accuracy of age estimation from the pubic bone. Specimens were collected from decedents of known age, sex, and race at the Forensic Science Center (FSC) in Phoenix, Arizona. The collection consists of pubic bones and fourth rib ends from 419 males and 211 females, ranging in age from 18 to 99. Age-at-death was estimated by three observers using the Suchey-Brooks method. The correlation results indicate that there are significant differences in the observed versus actual ages (r = 0.68169, p < 0.001) and that there are significant interobserver differences. No significant differences were found in the intra-observer tests. The FSC pubic bones were sorted based on morphology without knowing age. New descriptions and age ranges were created. A phase seven was described and is comprised of males and females over 70 years of age-at-death.

  13. Generating iPSC-Derived Choroidal Endothelial Cells to Study Age-Related Macular Degeneration

    PubMed Central

    Songstad, Allison E.; Wiley, Luke A.; Duong, Khahn; Kaalberg, Emily; Flamme-Wiese, Miles J.; Cranston, Cathryn M.; Riker, Megan J.; Levasseur, Dana; Stone, Edwin M.; Mullins, Robert F.; Tucker, Budd A.

    2015-01-01

    Purpose Age-related macular degeneration (AMD), the most common cause of incurable blindness in the western world, is characterized by the dysfunction and eventual death of choroidal endothelial (CECs), RPE, and photoreceptor cells. Stem cell–based treatment strategies designed to replace photoreceptor and RPE cells currently are a major scientific focus. However, the success of these approaches likely also will require replacement of the underlying, supportive choroidal vasculature. The purpose of this study was to generate stem cell–derived CECs to develop efficient differentiation and transplantation protocols. Methods Dermal fibroblasts from the Tie2-GFP mouse were isolated and reprogrammed into two independent induced pluripotent stem cell (iPSC) lines via viral transduction of the transcription factors Oct4, Sox2, Klf4, and c-Myc. Tie2-GFP iPSCs were differentiated into CECs using a coculture method with either the RF6A CEC line or primary mouse CECs. Induced pluripotent stem cell–derived CECs were characterized via RT-PCR and immunocytochemistry for EC- and CEC-specific markers. Results Induced pluripotent stem cells generated from mice expressing green fluorescent protein (GFP) under control of the endothelial Tie2 promoter display classic pluripotency markers and stem cell morphology. Induced pluripotent stem cell–derived CECs express carbonic anhydrase IV, eNOS, FOXA2, PLVAP, CD31, CD34, ICAM-1, Tie2, TTR, VE-cadherin, and vWF. Conclusions Induced pluripotent stem cell–derived CECs will be a valuable tool for modeling of choriocapillaris-specific insults in AMD and for use in future choroidal endothelial cell replacement approaches. PMID:26720480

  14. Assessing the congruence of thermal niche estimations derived from distribution and physiological data. A test using diving beetles.

    PubMed

    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.

  15. 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

  16. Dental age estimation in the living after completion of third molar mineralization: new data for Gustafson's criteria.

    PubMed

    Timme, M; Timme, W H; Olze, A; Ottow, C; Ribbecke, S; Pfeiffer, H; Dettmeyer, R; Schmeling, A

    2017-03-01

    There is a need for dental age estimation methods after completion of the third molar mineralization. Degenerative dental characteristics appear to be suitable for forensic age diagnostics beyond the 18th year of life. In 2012, Olze et al. investigated the criteria studied by Gustafson using orthopantomograms. The objective of this study was to prove the applicability and reliability of this method with a large cohort and a wide age range, including older individuals. For this purpose, 2346 orthopantomograms of 1167 female and 1179 male Germans aged 15 to 70 years were reviewed. The characteristics of secondary dentin formation, cementum apposition, periodontal recession and attrition were evaluated in all the mandibular premolars. The correlation of the individual characteristics with the chronological age was examined by means of a stepwise multiple regression analysis, in which the chronological age formed the dependent variable. Following those results, R (2) values amounted to 0.73 to 0.8; the standard error of estimate was 6.8 to 8.2 years. Fundamentally, the recommendation for conducting age estimations in the living by these methods can be shared. The values for the quality of the regression are, however, not precise enough for a reliable age estimation around regular retirement date ages. More precise regression formulae for the age group of 15 to 40 years of life are separately presented in this study. Further research should investigate the influence of ethnicity, dietary habits and modern health care on the degenerative characteristics in question.

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

    PubMed Central

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

    2015-01-01

    Aim: To assess the estimation of chronological age based on the stages of third molar development following the eight stages (A–H) method of Demirjian et al. in Chennai population of South India. Materials and Methods: A sample consisting of 848 individuals (471 males and 377 females) aged between 14 and 30 years was randomly selected for the clinical evaluation and 323 orthopantomograms with clinically missing third molars were taken for radiological evaluation using Demirjian's method from a Chennai population of known chronological age and sex. Statistical analysis was performed using Pearson's Chi-square test and mean values were compared between the study groups using t-test or analysis of variance (ANOVA) followed by Tukey's highly significant difference (HSD). In the present study, P < 0.05 was considered as the level of significance. Results: The results showed that the mean age of having clinically completely erupted maxillary third molars was 22.41 years in male subjects and 23.81 years in female subjects and that of mandibular third molars was 21.49 years in male subjects and 23.34 years in female subjects. Mandibular third molars were clinically missing more often in females than in males. Eruption of mandibular third molars was generally ahead of the emergence of maxillary third molars into the oral cavity. Third molar development between male and female subjects showed statistically significant differences at calcification stage F and stage G in maxillary third molars and stage F in mandibular third molars (P < 0.05). Conclusion: There are differences indicating that maxillary and mandibular third molar eruption reached Demirjian's formation stages earlier in males than in females. It is suggested that in future studies, to increase the accuracy of age determination, indications of sexual maturity and ossification should also be evaluated in addition to third molar mineralization. PMID:25984465

  18. Barotropic Mechanisms of Derivative-based Uncertainty Propagation in Drake Passage Transport Estimation

    NASA Astrophysics Data System (ADS)

    Kalmikov, A.; Heimbach, P.

    2013-12-01

    We apply derivative-based uncertainty quantification (UQ) and sensitivity methods to the estimation of Drake Passage transport in a global barotropic configuration of the MIT ocean general circulation model (MITgcm). Sensitivity and uncertainty fields are evaluated via first and second derivative codes of the MITgcm, generated via algorithmic differentiation (AD). Observation uncertainties are projected to uncertainties in the control variables by inversion of the Hessian of the nonlinear least-squares misfit function. Only data-supported components of Hessian information are retained through elimination of the unconstrained uncertainty nullspace. The assimilated observation uncertainty is combined with prior control variable uncertainties to reduce their posterior uncertainty. The spatial patterns of posterior uncertainty reduction and their temporal evolution are explained in terms of barotropic dynamics. Global uncertainty teleconnection mechanisms are identified as barotropic uncertainty waves. Uncertainty coupling across different control fields is demonstrated by assimilation of sea surface height uncertainty. A second step in our UQ scheme consists in propagating prior and posterior uncertainties of the model controls onto model output variables of interest, here Drake Passage transport. Forward uncertainty propagation amounts to matrix transformation of the uncertainty covariances via the model Jacobian and its adjoint. Sources of uncertainties of the transport are revealed through analysis of the adjoint wave dynamics in the model. These adjoint (reversed) mechanisms are associated with the evolution of sensitivity fields and our method formally extends sensitivity analysis to uncertainty quantification. Inverse uncertainty propagation mechanisms can be linked to adjoint dynamics in a similar manner. The posterior correlations of controls are found to dominate the reduction of the transport uncertainty compared to the marginal uncertainty reduction of the

  19. Magnitude, Location, and Ground Motion Estimates Derived From the Community Internet Intensity Maps

    NASA Astrophysics Data System (ADS)

    Quitoriano, V.; Wald, D. J.; Hattori, M. F.; Ebel, J. E.

    2002-12-01

    As is typical for stable continental region events, the 2002 Au Sable Forks, NY, and Evansville, IN, earthquakes had a dearth of ground motion recordings. In contrast, the USGS collected over 9,300 and 6600 Internet responses for these two events, respectively, through the Community Internet Intensity Map (CIIM) Web pages providing a valuable collection of intensity data. CIIM is an automatic system for rapidly generating seismic intensity maps based on shaking and damage reports collected from Internet users immediately following felt earthquakes in the United States. These intensities (CII) have been shown to be comparable to USGS Modified Mercalli Intensities (MMI). Given the CII for an event, we have developed tools to make it possible to generate ground motion estimates in the absence of data from seismic instruments. We compare both mean ground motion estimates based on the ShakeMap instrumental intensity relations with values computed from a Bayesian approach, based on combining probabilities of ground motion amplitudes for a given intensity with those for regionally-appropriate attenuation relationships. We also present a method for deriving earthquake magnitude and location automatically, updated as a function of time, from online responses based on the algorithm of Bakun and Wentworth. We perform a grid search centered on the area with the highest intensity responses, treat each node as a `trial epicenter', and determine the magnitude and intensity centroid that best fits the CII observation points according a region-dependent intensity-distance attenuation relation. We use the M4.9 2002 Gilroy, CA, event to test all these new tools since it was well recorded by strong motion instruments and had an impressive CIIM response. We show that the epicenter and ground motions determined from the CIIM data correlate well with instrumentally derived parameters. We then apply these methods to the Au Sable Forks, NY, and Evansville, IN, events. To show the

  20. Age estimation of archaeological remains using amino acid racemization in dental enamel: a comparison of morphological, biochemical, and known ages-at-death.

    PubMed

    Griffin, R C; Chamberlain, A T; Hotz, G; Penkman, K E H; Collins, M J

    2009-10-01

    The poor accuracy of most current methods for estimating age-at-death in adult human skeletal remains is among the key problems facing palaeodemography. In forensic science, this problem has been solved for unburnt remains by the development of a chemical method for age estimation, using amino acid racemization in collagen extracted from dentine. Previous application of racemization methods to archaeological material has proven problematic. This study presents the application to archaeological human remains of a new age estimation method utilizing amino acid racemization in a potentially closed system-the dental enamel. The amino acid composition and extent of racemization in enamel from two Medieval cemeteries (Newcastle Blackgate and Grantham, England) and from a documented age-at-death sample from a 19th century cemetery (Spitalfriedhof St Johann, Switzerland) were determined. Alterations in the amino acid composition were detected in all populations, indicating that diagenetic change had taken place. However, in the Medieval populations, these changes did not appear to have substantially affected the relationship between racemization and age-at-death, with a strong relationship being retained between aspartic acid racemization and the morphological age estimates. In contrast, there was a poor relationship between racemization and age in the post-medieval documented age-at-death population from Switzerland. This appears to be due to leaching of amino acids post-mortem, indicating that enamel is not functioning as a perfectly closed system. Isolation of amino acids from a fraction of enamel which is less susceptible to leaching may improve the success of amino acid racemization for archaeological age estimation.

  1. Near-Real Time Altimeter-Derived Estimates of Hurricane Heat Potential

    NASA Astrophysics Data System (ADS)

    Goni, G. J.; Black, P. G.; Cione, J. J.; Mainelli, M.; Trinanes, J. A.

    2001-12-01

    layer thickness, which is defined to go from the surface to the depth of the 20oC isotherm. Although there are many factors controlling the sea height anomaly, it is assumed here that most of its variability is due to changes in the thickness of the upper layer and to steric and barotropic effects. The thermal profiles are then constructed using near-real time altimeter-derived upper layer thickness from three altimeters by NOAA/NESDIS along with the sea surface temperature fields. Estimates of this parameter are posted daily during hurricane season to help forecasters and scientists on identifying regions of high hurricane heat potential and possible hurricane intensification.

  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

    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.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. [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.

  10. 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.

  11. 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.

  12. 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

    2014-05-23

    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.

  13. 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

  14. Are the new automated methods for bone age estimation advantageous over the manual approaches?

    PubMed

    De Sanctis, Vincenzo; Soliman, Ashraf T; Di Maio, Salvatore; Bedair, Said

    2014-12-01

    Bone Age Assessment (BAA) is performed worldwide for the evaluation of endocrine, genetic and chronic diseases, to monitor response to medical therapy and to determine the growth potential of children and adolescents. It is also used for consultation in planning orthopedic procedures, for determination of chronological age for adopted children, youth sports participation and in forensic settings. The main clinical methods for skeletal bone age estimation are the Greulich and Pyle (GP) and the Tanner and Whitehouse (TW) methods. Seventy six per cent (76%) of radiologists or pediatricians usually use the method of GP, 20% that of TW and 4% other methods. The advantages of using the TW method, as opposed to the GP method, are that it overcomes the subjectivity problem and results are more reproducible. However, it is complex and time consuming; for this reason its usage is just about 20% on a world-wide scale. Moreover, there are some evidences that bone age assignments by different physicians can differ significantly. Computerized and Quantitative Ultrasound Technologies (QUS) for assessing skeletal maturity have been developed with the aim of reducing many of the inconsistencies associated with radiographic investigations. In spite of the fact that the volume of automated methods for BAA has increased, the majotity of them are still in an early phase of development. QUS is comparable to the GP based method, but there is not enough established data yet for the healthy population. The Authors wish to stimulate the attention on the accuracy, reliability and consistency of BAA and to initiate a debate on manual versus automated approaches to enhance our assessment for skeletal matutation in children and adolescents.

  15. New method for estimation of adult skeletal age at death from the morphology of the auricular surface of the ilium.

    PubMed

    Igarashi, Yuriko; Uesu, Kagumi; Wakebe, Tetsuaki; Kanazawa, Eisaku

    2005-10-01

    A new method for estimating skeletal age at death from the morphology of the auricular surface of the ilium is presented. It uses a multiple regression analysis with dummy variables, and is based on the examination of 700 modern Japanese skeletal remains with age records. The observer using this method needs only to check for the presence or absence of nine (for a male) or seven (for a female) features on the auricular surface and to select the parameter estimates of each feature, calculated by multiple regression analysis with dummy variables. The observer can obtain an estimated age from the sum of parameter estimates. It is shown that a fine granular texture of the auricular surface is typical of younger individuals, whereas a heavily porous texture is characteristic of older individuals, and that both of these features are very useful for estimating age. Our method is shown here to be more accurate than other methods, especially in the older age ranges. Since the auricular surface allows more expedient observations than other parts of the skeleton, this new method can be expected to improve the overall accuracy of estimating skeletal age at death.

  16. New approach to age estimation of male and female adult skeletons based on the morphological characteristics of the acetabulum.

    PubMed

    San-Millán, Marta; Rissech, Carme; Turbón, Daniel

    2017-03-01

    Age estimation is essential to the human identification process, both in forensic and archeological contexts. Based on the previous male-specific method of Rissech et al. (J Forensic Sci, 2006, 51:213-229), a new approach to age estimation based on the acetabulum has been described and evaluated in 611 individuals from the Lisbon Collection (Lisbon, Portugal). This paper has two main goals: (1) to revise and better define the variables of Rissech's method related to the acetabular fossa, namely, variables 5, 6, and 7, and (2) to extend the applicability of this new approach to both sexes while analyzing age-related sex differences in the acetabular aging process. The results demonstrate the suitability of combining acetabulum traits and a Bayesian approach to estimating age in adults of both sexes. This study has confirmed the usefulness of the redefined variables of the acetabular fossa when age-related changes are considered. Furthermore, the newly defined variables have good to excellent values of repeatability. The study has also extended the method's applicability to females. The revised method has absolute error averages of 7.28 years for males and 7.09 years for females, based on a sex-specific reference sample. In addition, approximately 74 % of the individuals estimated had an absolute error less than 10 years. Interestingly, the acetabular aging process follows similar trends in both sexes, but the aging rate seems to be different between males and females, especially in middle-aged individuals. Despite the fact that the age estimates, on average, did not improve significantly with the use of a sex-specific reference sample, it is recommended that the sexes be analyzed separately due to the differences in aging rates and inaccuracy values.

  17. Derivation of PHD-TBD filter and comments on `joint detection and estimation of multiple objects from image observations'

    NASA Astrophysics Data System (ADS)

    Shi, Zhi-guang; Zhang, Yan

    2016-09-01

    In this paper, through analyzing the derivation process and computer simulations, we find that the update formulas for PHD-TBD filter in paper [5] are somewhat unreasonably. When using the paper's PHD update formula, the targets' state parameters cannot be estimated. Following the method in paper 2, we treat the objects to be detected in TBD situations as special extended targets and derive a new PHD-TBD update formula analytically under this assumption. The correctness of the derivation is validated by computer simulations.

  18. 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.

  19. Cycle life estimation of lithium secondary battery by extrapolation method and accelerated aging test

    NASA Astrophysics Data System (ADS)

    Takei, K.; Kumai, K.; Kobayashi, Y.; Miyashiro, H.; Terada, N.; Iwahori, T.; Tanaka, T.

    The testing methods to estimate the life cycles of lithium ion batteries for a short period, have been developed using a commercialized cell with LiCoO 2/hard carbon cell system. The degradation reactions with increasing cycles were suggested to occur predominantly above 4 V from the results of operating voltage range divided tests. In the case of the extrapolation method using limited cycle data, the straight line approximation was useful as the cycle performance has the linearity, but the error is at most 40% in using the initial short cycle data. In the case of the accelerated aging tests using the following stress factors, the charge and/or discharge rate, large accelerated coefficients were obtained in the high charge rate and the high temperature thermal stress.

  20. Integrated Diagnostic and Prognostic Tools for Residual Life Estimation in Aging Nuclear Power Plant Components

    SciTech Connect

    Ramuhalli, Pradeep; Meyer, Ryan M.; Bond, Leonard J.; Griffin, Jeffrey W.; Henager, Charles H.

    2011-06-01

    Recent events in Japan have focused renewed attention on the safe operation of light water reactor (LWR) nuclear power plants (NPPs). A central issue in safe, long-term operations of existing and planned NPPs is the early detection and monitoring of significant materials degradation. Materials aging and degradation in passive components is expected to be the key factor in determining the operational life of an NPP and may limit long-term operations in the current LWR fleet. Methods for detecting and assessing the degradation state in NPP structural materials, followed by approaches to estimate the remaining useful life (RUL) of the component, are therefore necessary for safe, long-term operations. This paper explores advanced diagnostic and prognostic approaches to detecting material degradation, and then determining RUL given the current material state.

  1. Sensitive detection and estimation of cell-derived peroxynitrite fluxes using fluorescein-boronate.

    PubMed

    Rios, Natalia; Piacenza, Lucía; Trujillo, Madia; Martínez, Alejandra; Demicheli, Verónica; Prolo, Carolina; Álvarez, María Noel; López, Gloria V; Radi, Rafael

    2016-12-01

    The specific and sensitive detection of peroxynitrite (ONOO(-)/ONOOH) in biological systems is a great challenge due to its high reactivity towards several biomolecules. Herein, we validated the advantages of using fluorescein-boronate (Fl-B) as a highly sensitive fluorescent probe for the direct detection of peroxynitrite under biologically-relevant conditions in two different cell models. The synthesis of Fl-B was achieved by a very simply two-step conversion synthetic route with high purity (>99%) and overall yield (∼42%). Reactivity analysis of Fl-B with relevant biological oxidants including hydrogen peroxide (H2O2), hypochlorous acid (HOCl) and peroxynitrite were performed. The rate constant for the reaction of peroxynitrite with Fl-B was 1.7×10(6)M(-1)s(-1), a million times faster than the rate constant measured for H2O2 (k=1.7M(-1)s(-1)) and 2,700 faster than HOCl (6.2×10(2)M(-1)s(-1)) at 37°C and pH 7.4. The reaction of Fl-B with peroxynitrite was significant even in the presence of physiological concentrations of CO2, a well-known peroxynitrite reactant. Experimental and simulated kinetic analyses confirm that the main oxidation process of Fl-B takes place with peroxynitrite itself via a direct bimolecular reaction and not with peroxynitrite-derived radicals. Fl-B was successfully applied for the detection of endogenously-generated peroxynitrite by endothelial cells and in macrophage-phagocyted parasites. Moreover, the generated data allowed estimating the actual intracellular flux of peroxynitrite. For instance, ionomycin-stimulated endothelial cells generated peroxynitrite at a rate of ∼ 0.1μMs(-1), while immunostimulated macrophages do so in the order of ∼1μMs(-1) inside T. cruzi-infected phagosomes. Fl-B revealed not to be toxic in concentrations up to 1mM for 24h. Cellular peroxynitrite detection was achieved by conventional laboratory fluorescence-based methods including flow cytometry and epi-fluorescence microscopy. Fl-B was shown to be

  2. 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.

  3. QED Estimates of the 1990-91 Schools and Staffing Survey: Deriving and Comparing QED School Estimates with CCD Estimates. Working Paper Series.

    ERIC Educational Resources Information Center

    Holt, Albert; Scanlon, Brian R.

    This study examines the magnitude of the difference between estimates from the 1990-91 Schools and Staffing Survey (SASS) using a Common Core of Data (CCD) definition of a school and a Quality Education Data (QED) definition of a school. The 1990-91 SASS sample design allows for the development of school and administrator estimates using either…

  4. Lateral stability and control derivatives of a jet fighter airplane extracted from flight test data by utilizing maximum likelihood estimation

    NASA Technical Reports Server (NTRS)

    Parrish, R. V.; Steinmetz, G. G.

    1972-01-01

    A method of parameter extraction for stability and control derivatives of aircraft from flight test data, implementing maximum likelihood estimation, has been developed and successfully applied to actual lateral flight test data from a modern sophisticated jet fighter. This application demonstrates the important role played by the analyst in combining engineering judgment and estimator statistics to yield meaningful results. During the analysis, the problems of uniqueness of the extracted set of parameters and of longitudinal coupling effects were encountered and resolved. The results for all flight runs are presented in tabular form and as time history comparisons between the estimated states and the actual flight test data.

  5. Glucose-derived AGEs promote migration and invasion of colorectal cancer by up-regulating Sp1 expression.

    PubMed

    Deng, Ruyuan; Wu, Huo; Ran, Hui; Kong, Xiang; Hu, Lei; Wang, Xiao; Su, Qing

    2017-02-22

    It is well established that the risk of colorectal cancer (CRC) is significantly increased in diabetic patients. As one of main forms of the advanced glycation end products (AGEs) that accumulate in vivo, glucose-derived AGEs play an important role in the pathogenesis of diabetic complications and may contribute to CRC progression. However, to date, both the contribution of glucose-derived AGEs to the course of CRC and the underlying mechanism are unclear. In the present study, the concentration of glucose-derived AGEs in the serum and tumor tissue of patients with CRC increased. A clinical data analysis demonstrated that the expression of the receptor for AGEs (RAGE), Specificity Protein 1 (Sp1), and matrix metallopeptidase -2 (MMP2) was significantly higher in cancerous tissues compared with non-tumor tissue in Chinese Han patients with CRC and that RAGE expression was closely associated with lymph node metastasis and TNM stage. Furthermore, in vivo and in vitro experiments showed that AGEs promoted invasion and migration of colorectal cancer, and the AGEs treatment increased the expression of RAGE, Sp1, and MMP2 in a dose-dependent manner. A RAGE blocking antibody and an Sp1-specific siRNA attenuated the AGE-induced effects. Moreover, the AGEs treatment increased the phosphorylation of ERK, and reducing the phosphorylation level of ERK by MEK1/2 inhibitor decreased the expression of Sp1. In conclusion, glucose-derived AGEs promote the invasion and metastasis of CRC partially through the RAGE/ERK/SP1/MMP2 cascade. These findings may provide an explanation for the poor prognoses of colorectal cancer in diabetic patients.

  6. Improved age estimates for key Late Quaternary European tephra horizons in the RESET lattice

    NASA Astrophysics Data System (ADS)

    Bronk Ramsey, Christopher; Albert, Paul G.; Blockley, Simon P. E.; Hardiman, Mark; Housley, Rupert A.; Lane, Christine S.; Lee, Sharen; Matthews, Ian P.; Smith, Victoria C.; Lowe, John J.

    2015-06-01

    The research project 'Response of Humans to Abrupt Environmental Transitions' (RESET) used tephra layers to tie together and synchronise the chronologies of stratigraphic records at archaeological and environmental sites. With the increasing importance of tephra as chronological markers in sedimentary sequences, both in this project and more generally, comes a requirement to have good estimates for the absolute age of these volcanic horizons. This paper summarises the chronology of the key tephra in the RESET tephra lattice in the time range 10-60 ka BP, from the existing literature, from papers produced as part of the RESET project, and reanalysis conducted for this paper. The paper outlines the chronological approach taken to the dating of tephra within the RESET project, and the basis for further work, as part of the INTIMATE (INTegrating Ice core MArine and TErrestrial records) initiative. For each of the tephra layers in the lattice, the existing literature is discussed and, where relevant date estimates updated using the latest radiocarbon calibration curves (IntCal13 and Marine13) and methods. Maps show the approximate extent of tephra finds, giving a visual indication of the coverage of the lattice in different time-periods.

  7. Estimation of genetic parameters for longevity considering the cow's age at last calving.

    PubMed

    Caetano, Sabrina L; Rosa, Guilherme J M; Savegnago, Rodrigo P; Ramos, Salvador B; Bernardes, Priscila A; Bezerra, Luiz A F; Lôbo, Raysildo B; de Paz, Claudia C P; Munari, Danísio Prado

    2017-02-01

    The aim of this study was to estimate heritability and predict breeding values for longevity among cows in herds of Nellore breed, considering the trait cow's age at last calving (ALC), by means of survival analysis methodology. The records of 11,791 animals from 22 farms were used. The variable ALC has been used by a criterion that made it possible to include cows not only at their first calving but also at their ninth calving. The criterion used was the difference between the date of each cow's last calving and the date of the last calving on each farm. If this difference was greater than 36 months, the cow was considered to have failed and uncensored. If not, this cow was censored, thus indicating that future calving remained possible for this cow. The survival model used for the analyses was the proportional hazards model, and the base risk was given by a Weibull distribution. The heritability estimate obtained was equal to 0.25. It was found that the ALC variable had the capacity to respond to selection for the purpose of increasing the longevity of the cows in the herds.

  8. Revised age estimates of Brunhes palaeomagnetic events - Support for a link between geomagnetism and eccentricity

    NASA Technical Reports Server (NTRS)

    Rampino, M. R.

    1981-01-01

    Revisions in the dates of reported geomagnetic excursions during the Brunhes Epoch are proposed in light of possible correlations between a section at Gioia Tauro, Italy, deep-sea cores, a core from Lake Biwa, Japan, and some lava flows. The anomalously long, double Blake Event reported at Gioia Tauro is here correlated with the Blake Event (approximately 110 kyr) and the Biwa 1 event (180 plus or minus 5 kyr); an hiatus may be present in the section between these two events. The alpha event at Gioia Tauro is correlated with the Biwa 2 event at about 295 kyr; the beta event with the 'Biwa 3' event at about 400 kyr; the gamma event with the Snake River event at 480 plus or minus 50; and the delta event, not recorded elsewhere, is estimated to have occurred at approximately 620 kyr. These proposed refinements in the age estimates of the excursions suggest an approximately 100 kyr cyclicity. If the events are real and the revised dating is correct, the timing of the geomagnetic events seems to coincide with times of peak eccentricity of the earth's orbit, suggesting a causal connection.

  9. Detection of non-coloured anthocyanin-flavanol derivatives in Rioja aged red wines by liquid chromatography-mass spectrometry.

    PubMed

    Sánchez-Ilárduya, María Belén; Sánchez-Fernández, Cristina; Garmón-Lobato, Sergio; Abad-García, Beatriz; Berrueta, Luis Angel; Gallo, Blanca; Vicente, Francisca

    2014-04-01

    Anthocyanins, responsible for wine colour, are involved in many reactions during wine ageing. Anthocyanin-flavanol associations give rise to derivatives in flavylium form that provide blue hues, but also derivatives that do not directly influence wine colour. These colourless derivatives remain mostly unknown but their roles during wine ageing are important for controlling wine quality. Colourless anthocyanin-flavanol derivatives formed during wine ageing have been studied in three aged red wines from Rioja using a combined method with Column Chromatography (CC) and High Performance Liquid Chromatography with Diode Array and Mass Spectrometric detections (HPLC-DADMS). Twenty-six compounds have been detected: 17 dimers with the anthocyanin in flavene form with possible anthocyanin-flavanol (type 1) and flavanol-anthocyanin (type 2) structures, and 9 with an A-type bicyclic anthocyanin-flavanol structure (type 3). Although some of malvidin derivatives have been previously reported, this is the first time that these derivatives (including different isomers) have also been detected for delphinidin, petunidin and peonidin.

  10. 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

  11. 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.

  12. 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.

  13. Estimated acceptance of HPV vaccination among Italian women aged 18-26 years.

    PubMed

    Giambi, Cristina; Donati, Serena; Declich, Silvia; Salmaso, Stefania; Ciofi Degli Atti, Marta Luisa; Alibrandi, Maria Pia; Brezzi, Silvia; Carozzi, Francesca; Collina, Natalina; Franchi, Daniela; Lattanzi, Amedeo; Meda, Margherita; Minna, Maria Carmela; Nannini, Roberto; Scherillo, Isabella; Bella, Antonino

    2011-10-26

    In Italy vaccination against human papillomavirus (HPV) was introduced in the national immunization programme in 2007; the primary target for this vaccination is 11-year-old females, whereas vaccination for older age groups is still a matter of debate. This project was carried out in the period 2007-2009 to estimate the acceptance rate among 18-26-year-old, to whom free-of-charge vaccination was actively offered. Socio-demographic factors associated with acceptance were also investigated. A sample of 1159 women was randomly selected from resident population lists of 10 Local Health Units in 6 of Italy's 21 Regions; 1032 women were deemed eligible for the study. Of the eligible women, 580 received at least one vaccine dose for an acceptance rate of 56.2% and 542 received all three vaccine doses (52.6%). The acceptance rate was significantly higher for: residents of northern and central Italy (OR(adj)=2.22, 95%CI 1.64-3.01 and OR(adj)=1.77, 95%CI, 1.20-2.61 respectively), compared to southern Italy; women with a high educational level (OR(adj)=1.41; 95%CI: 1.02-1.93); and students (OR(adj)=1.64; 95%CI: 1.13-2.37). The low immunization rate highlights the difficulties of reaching young adult women, although the current coverage rates observed in the primary target population of HPV vaccination campaign (64%) emphasize that achieving high coverage rates is challenging also in younger age groups. Our results suggest that it would be premature to extend the active free-of-charge offer of HPV vaccination to older women and that efforts should be focused on the priority target, considering that the objective of 95% coverage established for this age group is still far from being attained.

  14. Curriculum-Based Measurement of Oral Reading: Evaluation of Growth Estimates Derived with Pre-Post Assessment Methods

    ERIC Educational Resources Information Center

    Christ, Theodore J.; Monaghen, Barbara D.; Zopluoglu, Cengiz; Van Norman, Ethan R.

    2013-01-01

    Curriculum-based measurement of oral reading (CBM-R) is used to index the level and rate of student growth across the academic year. The method is frequently used to set student goals and monitor student progress. This study examined the diagnostic accuracy and quality of growth estimates derived from pre-post measurement using CBM-R data. A…

  15. Ages and Accumulation Rates of the Martian Polar Layered Deposits Estimated from Orbital Tuning

    NASA Astrophysics Data System (ADS)

    Sori, M.; Bailey, E. A.; Perron, J.; Huybers, P. J.; Aharonson, O.; Limaye, A.

    2013-12-01

    Layers of dusty water ice in the polar caps of Mars have been hypothesized to record climate changes driven by variation of the planet's orbit and spin axis, but the time interval over which the polar layered deposits (PLDs) formed is unknown, and an orbital influence has not been conclusively demonstrated. We performed orbital tuning of reconstructed PLD stratigraphic sequences in an attempt to constrain the accumulation interval and test for the presence of an orbital signal. Our procedure uses dynamic time warping (DTW) to search for a match between two time series - the polar insolation history and brightness or topographic information in the PLDs - and then assesses the significance of potential matches using a Monte Carlo procedure. We selected 30 images of the northern PLDs from the Mars Orbiter Camera (MOC) aboard the Mars Global Surveyor spacecraft and used Mars Orbiter Laser Altimeter profiles to transform each image into a record of image brightness as a function of vertical depth. To constrain the PLD age and accumulation rate, we tuned each image record to Martian insolation records for varying time intervals. If a particular insolation interval produced the strongest match to an image, and if the match became weaker as the image was tuned to progressively longer or shorter intervals, we chose the best-fitting interval as an estimated accumulation time for that PLD sequence, and used the depth range to estimate a corresponding PLD accumulation rate. We also tuned the insolation records to synthetic records containing no orbital influence to test whether the image matches were spurious. Of the 30 MOC images analyzed, 16 produce insolation intervals that we consider strong matches. These images yield an average deposition rate of 0.5 × 0.2 mm/yr for the northern PLDs. The images represent only a fraction of the entire stratigraphy; extrapolating that deposition rate farther back in time yields an age of ~4 Ma for the entire PLD sequence present in the

  16. 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.

  17. Steady state estimation of soil organic carbon using satellite-derived canopy leaf area index

    DOE PAGES

    Fang, Yilin; Liu, Chongxuan; Huang, Maoyi; ...

    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

  18. 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

  19. Clinically derived early postoperative pain trajectories differ by age, sex, and type of surgery.

    PubMed

    Tighe, Patrick J; Le-Wendling, Linda T; Patel, Ameet; Zou, Baiming; Fillingim, Roger B

    2015-04-01

    The objective of this study was to determine the effects of age, sex, and type of surgery on postoperative pain trajectories derived in a clinical setting from pain assessments in the first 24 hours after surgery. This study is a retrospective cohort study using a large electronic medical records system to collect and analyze surgical case data. The sample population included adult patients undergoing nonambulatory nonobstetric surgery in a single institution over a 1-year period. Analyses of postoperative pain trajectories were performed using a linear mixed-effects model. Pain score observations (91,708) from 7293 patients were included in the statistical analysis. On average, the pain score decreased about 0.042 (95% confidence interval [CI]: -0.044 to -0.040) points on the numerical rating scale (NRS) per hour after surgery for the first 24 postoperative hours. The pain score reported by male patients was approximately 0.27 (95% CI: -0.380 to -0.168) NRS points lower than that reported by females. Pain scores significantly decreased over time in all age groups, with a slightly more rapid decrease for younger patients. Pain trajectories differed by anatomic location of surgery, ranging from -0.054 (95% CI: -0.062 to -0.046) NRS units per hour for integumentary and nervous surgery to -0.104 (95% CI: -0.110 to -0.098) NRS units per hour for digestive surgery, and a positive trajectory (0.02 [95% CI: 0.016 to 0.024] NRS units per hour) for musculoskeletal surgery. Our data support the important role of time after surgery in considering the influence of biopsychosocial and clinical factors on acute postoperative pain.

  20. 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.

  1. Development of modern human subadult age and sex estimation standards using multi-slice computed tomography images from medical examiner's offices

    NASA Astrophysics Data System (ADS)

    Stock, Michala K.; Stull, Kyra E.; Garvin, Heather M.; Klales, Alexandra R.

    2016-10-01

    Forensic anthropologists are routinely asked to estimate a biological profile (i.e., age, sex, ancestry and stature) from a set of unidentified remains. In contrast to the abundance of collections and techniques associated with adult skeletons, there is a paucity of modern, documented subadult skeletal material, which limits the creation and validation of appropriate forensic standards. Many are forced to use antiquated methods derived from small sample sizes, which given documented secular changes in the growth and development of children, are not appropriate for application in the medico-legal setting. Therefore, the aim of this project is to use multi-slice computed tomography (MSCT) data from a large, diverse sample of modern subadults to develop new methods to estimate subadult age and sex for practical forensic applications. The research sample will consist of over 1,500 full-body MSCT scans of modern subadult individuals (aged birth to 20 years) obtained from two U.S. medical examiner's offices. Statistical analysis of epiphyseal union scores, long bone osteometrics, and os coxae landmark data will be used to develop modern subadult age and sex estimation standards. This project will result in a database of information gathered from the MSCT scans, as well as the creation of modern, statistically rigorous standards for skeletal age and sex estimation in subadults. Furthermore, the research and methods developed in this project will be applicable to dry bone specimens, MSCT scans, and radiographic images, thus providing both tools and continued access to data for forensic practitioners in a variety of settings.

  2. 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.

  3. 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.

  4. 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.

  5. Age-at-death estimation based on radiological and image analysis methods in clavicle in a current Spanish population.

    PubMed

    Benito, María; Sánchez, José Antonio; Codinha, Sónia

    2014-05-01

    Age-at-death estimation in adult individuals is one of the most challenging issues in forensic anthropology, namely, due to the large age intervals provided by the current methods, which demand the development of more reliable investigations. The clavicle has been studied as an age-at-death indicator in many researches for its accessibility, low biomechanical implication in locomotion and accuracy to predict age at death when other age indicators are not available. The present study was developed on a sample of 332 clavicles from adult individuals of known sex and age from the current Spanish population. They were x-rayed and digitalized, in a standardized way, using a Sedecal X-ray generator, model SHF 415. Three indices were calculated at the mid-diaphysis point (anterior index, posterior index, and total index) which relate the cortical thickness and the total clavicle thickness to age at death. The average grey level was also calculated in a 0.5-cm(2) area of the sternal and acromial ends (sternal grey average, acromial grey average), using Image J software. The data were subjected to a statistical analysis, using SPSS, version 15.0. The results show that average grey level has a weaker correlation with age than the variables which are based on the cortical thickness. On the other hand, the regression equations, which were calculated combining all the variables, provided smaller age-at-death intervals, demonstrating the usefulness of this method for adult age-at-death estimation in forensic anthropology.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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

  12. Letter report: Population estimates by age, sex and race for 10-county study area. Hanford Environmental Dose Reconstruction Project

    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.

  13. A comparison of ages estimated by the polarized light method with ages estimated by vertebrae in females of Coryphaenoides acrolepis (Pisces: Macrouridae)

    NASA Astrophysics Data System (ADS)

    Wilson, Raymond R.

    1982-11-01

    Rings of scales seen by the use of polarized light are compared to those of vertebral centra of the Pacific grenadier Coryphaenoides acrolepis (Bean). Although the number of rings in the two structures from the same individual show significant statistical agreement, strict numerical agreement occurred in only 22 out of 100 comparisons. Ageing by either technique produced comparable logistic growth curves.

  14. The radiocarbon age of calcite dissolving at the sea floor: Estimates from pore water data

    SciTech Connect

    Martin, W.R.; McNichol, A.P.; McCorkle, D.C.

    2000-04-01

    The authors measured the radiocarbon content and stable isotopic composition of pore water and bottom water {Sigma}CO{sub 2}, sedimentary organic carbon, and CaCO{sub 3} at two sites on the Ceara Rise, one underlying bottom water that is supersaturated with respect to calcite (Site B), the other underlying under saturated bottom water (Site G). The results were combined with pore water O{sub 2}, {Sigma}CO{sub 2}, and Ca{sup 2+} profiles (Martin and Sayles, 1996) to estimate the radiocarbon content of the CaCO{sub 3} that is dissolving in the sediment mixed layer. At Site G, the CaCO{sub 3} that is dissolving in the upper 2 cm of the sediments is clearly younger (richer in {sup 14}C) than the bulk sedimentary CaCO{sub 3}, indicating that nonhomogeneous CaCO{sub 3} dissolution occurs there. The case for nonhomogeneous dissolution is much weaker at the site underlying supersaturated bottom water. The results indicate that nonhomogeneous dissolution occurs in sediments underlying under saturated bottom water, that the dissolution is rapid relative to the rate of homogenization of the CaCO{sub 3} in the mixed layer by bioturbation, and that the dissolution rate of CaCO{sub 3} decreases as it ages in the sediment mixed layer. The results support the hypothesis, based on solid phase analyses, that the preferential dissolution of young (i.e., radiocarbon-rich) CaCO{sub 3} leads to a pattern of increasing radiocarbon age of mixed-layer CaCO{sub 3} as the degree of under saturation of bottom water increases (Keir, 1984; Broecker et al., 1991).

  15. Forensic age estimation in anti-piracy trials in Seychelles: Experiences and challenges faced.

    PubMed

    Gunawardena, S A; Liyanage, U A; Weeratna, J B; Mendis, N D N A; Perera, H J M; Jayasekara, R W; Fernando, R

    2017-01-01

    Forensic age estimation (FAE) was conducted using a multifactorial method on thirteen Somali detainees claiming juvenile status during the anti-piracy trials of the Seychelles Supreme Court in 2014/2015. A multidisciplinary team, comprising of four of the authors covering specialties in forensic medicine, forensic odontology and radiology, conducted the FAE using a five-stage protocol. Each detainee was interviewed with an interpreter and examined for disorders affecting dental/skeletal development and for assessment of genital development through Tanner staging. Dental maturity was assessed clinically and radiologically. Eruption stage was assessed using Olze et al. and mandibular third-molar maturity was assessed using Demirjian's classification. Skeletal maturity was assessed from hand-wrist X-rays according to Greulich & Pyle and from CT-clavicle according to Kellinghaus et al. and Schultz et al. Interpretation of findings was done using reference population data from similar ethnic and social backgrounds wherever possible. Final age-ranges were calculated by combining dental and clavicle maturity stages using the regression formula developed by Bassed et al. followed by a 10% correction factor. The team later testified on their findings under cross-examination. The protocol adopted by the authors increased the scientific validity of the findings and was useful in addressing cross-examination queries on exclusion of developmental disorders, ethnic/socioeconomic variability and maintaining chain of custody. Unforeseen jurisdictional and practical limitations were experienced but did not affect the outcome. Combining dental and clavicle developmental data provided the court with a much clearer picture on the likelihood of the detainees' juvenile status which emphasizes the importance of conducting more population studies using combinations of different developmental sites. The authors note that available reference data is mostly from affluent populations whereas

  16. A sequential Bayesian approach for the estimation of the age-depth relationship of the Dome Fuji ice core

    NASA Astrophysics Data System (ADS)

    Nakano, Shin'ya; Suzuki, Kazue; Kawamura, Kenji; Parrenin, Frédéric; Higuchi, Tomoyuki

    2016-02-01

    A technique for estimating the age-depth relationship in an ice core and evaluating its uncertainty is presented. The age-depth relationship is determined by the accumulation of snow at the site of the ice core and the thinning process as a result of the deformation of ice layers. However, since neither the accumulation rate nor the thinning process is fully known, it is essential to incorporate observational information into a model that describes the accumulation and thinning processes. In the proposed technique, the age as a function of depth is estimated by making use of age markers and δ18O data. The age markers provide reliable age information at several depths. The data of δ18O are used as a proxy of the temperature for estimating the accumulation rate. The estimation is achieved using the particle Markov chain Monte Carlo (PMCMC) method, which is a combination of the sequential Monte Carlo (SMC) method and the Markov chain Monte Carlo method. In this hybrid method, the posterior distributions for the parameters in the models for the accumulation and thinning process are computed using the Metropolis method, in which the likelihood is obtained with the SMC method, and the posterior distribution for the age as a function of depth is obtained by collecting the samples generated by the SMC method with Metropolis iterations. The use of this PMCMC method enables us to estimate the age-depth relationship without assuming either linearity or Gaussianity. The performance of the proposed technique is demonstrated by applying it to ice core data from Dome Fuji in Antarctica.

  17. Mitochondrial-derived reactive oxygen species (ROS) play a causal role in aging-related intervertebral disc degeneration.

    PubMed

    Nasto, Luigi A; Robinson, Andria R; Ngo, Kevin; Clauson, Cheryl L; Dong, Qing; St Croix, Claudette; Sowa, Gwendolyn; Pola, Enrico; Robbins, Paul D; Kang, James; Niedernhofer, Laura J; Wipf, Peter; Vo, Nam V

    2013-07-01

    Oxidative damage is a well-established driver of aging. Evidence of oxidative stress exists in aged and degenerated discs, but it is unclear how it affects disc metabolism. In this study, we first determined whether oxidative stress negatively impacts disc matrix metabolism using disc organotypic and cell cultures. Mouse disc organotypic culture grown at atmospheric oxygen (20% O(2)) exhibited perturbed disc matrix homeostasis, including reduced proteoglycan synthesis and enhanced expression of matrix metalloproteinases, compared to discs grown at low oxygen levels (5% O(2)). Human disc cells grown at 20% O(2) showed increased levels of mitochondrial-derived superoxide anions and perturbed matrix homeostasis. Treatment of disc cells with the mitochondria-targeted reactive oxygen species (ROS) scavenger XJB-5-131 blunted the adverse effects caused by 20% O(2). Importantly, we demonstrated that treatment of accelerated aging Ercc1(-/Δ) mice, previously established to be a useful in vivo model to study age-related intervertebral disc degeneration (IDD), also resulted in improved disc total glycosaminoglycan content and proteoglycan synthesis. This demonstrates that mitochondrial-derived ROS contributes to age-associated IDD in Ercc1(-/Δ) mice. Collectively, these data provide strong experimental evidence that mitochondrial-derived ROS play a causal role in driving changes linked to aging-related IDD and a potentially important role for radical scavengers in preventing IDD.

  18. 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

  19. Hierarchical Bayesian Model (HBM)-Derived Estimates of Air Quality for 2004 - Annual Report

    EPA Science Inventory

    This report describes EPA's Hierarchical Bayesian model-generated (HBM) estimates of O3 and PM2.5 concentrations throughout the continental United States during the 2004 calendar year. HBM estimates provide the spatial and temporal variance of O3 ...

  20. Hierarchical Bayesian Model (HBM)-Derived Estimates of Air Quality for 2002– Annual Report

    EPA Science Inventory

    This report describes EPA's Hierarchical Bayesian model-generated (HBM) estimates of O3 and PM2.5 concentrations throughout the continental United States during the 2002 calendar year. HBM estimates provide the spatial and temporal variance of O3 ...

  1. Hierarchical Bayesian Model (HBM)-Derived Estimates of Air Quality for 2001 - Annual Report

    EPA Science Inventory

    This report describes EPA's Hierarchical Bayesian model-generated (HBM) estimates of O3 and PM2.5 concentrations throughout the continental United States during the 2001 calendar year. HBM estimates provide the spatial and temporal variance of O 3...

  2. Hierarchical Bayesian Model (HBM)-Derived Estimates of Air Quality for 2003 – Annual Report

    EPA Science Inventory

    This report describes EPA's Hierarchical Bayesian model-generated (HBM) estimates of O3 and PM2.5 concentrations throughout the continental United States during the 2003 calendar year. HBM estimates provide the spatial and temporal variance of O3 ...

  3. Hierarchical Bayesian Model (HBM)-Derived Estimates of Air Quality for 2005 - Annual Report

    EPA Science Inventory

    This report describes EPA's Hierarchical Bayesian model-generated (HBM) estimates of O3 and PM2.5 concentrations throughout the continental United States during the 2005 calendar year. HBM estimates provide the spatial and temporal variance of O3 ...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Woody encroachment is a globally occurring phenomenon that is thought to contribute significantly to the global carbon (C) sink. The C contribution needs to be estimated at regional and local scales to address large uncertainties present in the global- and continental-scale estimates and guide regio...

  5. Hierarchical Bayesian Model (HBM)-Derived Estimates of Air Quality for 2006 - Annual Report

    EPA Science Inventory

    This report describes EPA's Hierarchical Bayesian model-generated (HBM) estimates of O3 and PM2.5 concentrations throughout the continental United States during the 2006 calendar year. HBM estimates provide the spatial and temporal variance of O3 ...

  6. Preliminary estimates of residence times and apparent ages of ground water in the Chesapeake Bay watershed, and water-quality data from a survey of springs

    USGS Publications Warehouse

    Focazio, Michael J.; Plummer, L. Neil; Bohlke, John K.; Busenberg, Eurybiades; Bachman, L. Joseph; Powars, David S.

    1998-01-01

    Knowledge of the residence times of the ground-water systems in Chesapeake Bay watershed helps resource managers anticipate potential delays between implementation of land-management practices and any improve-ments in river and estuary water quality. This report presents preliminary estimates of ground-water residence times and apparent ages of water in the shallow aquifers of the Chesapeake Bay watershed. A simple reservoir model, published data, and analyses of spring water were used to estimate residence times and apparent ages of ground-water discharge. Ranges of aquifer hydraulic characteristics throughout the Bay watershed were derived from published literature and were used to estimate ground-water residence times on the basis of a simple reservoir model. Simple combinations of rock type and physiographic province were used to delineate hydrogeomorphic regions (HGMR?s) for the study area. The HGMR?s are used to facilitate organization and display of the data and analyses. Illustrations depicting the relation of aquifer characteristics and associated residence times as a continuum for each HGMR were developed. In this way, the natural variation of aquifer characteristics can be seen graphically by use of data from selected representative studies. Water samples collected in September and November 1996, from 46 springs throughout the watershed were analyzed for chlorofluorocarbons (CFC?s) to estimate the apparent age of ground water. For comparison purposes, apparent ages of water from springs were calculated assuming piston flow. Additi-onal data are given to estimate apparent ages assuming an exponential distribution of ages in spring discharge. Additionally, results from previous studies of CFC-dating of ground water from other springs and wells in the watershed were compiled. The CFC data, and the data on major ions, nutrients, and nitrogen isotopes in the water collected from the 46 springs are included in this report. The apparent ages of water

  7. Diagnostic and Prognostic Tools for Residual Life Estimation in Aging Nuclear Power Plant Components

    SciTech Connect

    Ramuhalli, Pradeep; Bond, Leonard J.; Griffin, Jeffrey W.; Henager, Charles H.; Dixit, Mukul

    2011-06-23

    A central issue in life extension for the current fleet of light water nuclear power reactors (LWR) is the early detection and monitoring of significant materials degradation. To meet this need, nondestructive methods that are suitable for continuous monitoring over extended time periods (months to years) are needed. A related issue is the ability to estimate remaining useful life (RUL) of components and systems based on condition assessment or degradation information. Monitoring for early detection of materials degradation requires novel sensors and enhanced data integration techniques. A range of acoustic and electromagnetic measurement methods may be suitable, including acoustic microscopy, eddy current and magnetic Barkhausen emission. Prognostic methods that predict rate of degradation and remaining life based on phenomena that can be described by linear elastic fracture mechanics have been reported by several researchers. However, the challenge of predicting remaining life starting from earlier phases of degradation is largely unsolved. This paper discusses an assessment of selected diagnostic techniques, and the application of Bayesian prognostic algorithms to detection of early degradation and rate of degradation/life prediction. Such measurement and modeling methods are expected to form the basis for a new range of advanced diagnostic and prognostic approaches for assessing and monitoring life extension of ageing light water reactors.

  8. Diagnostic and Prognostic Tools for Residual Life Estimation in Aging Nuclear Power Plant Components

    NASA Astrophysics Data System (ADS)

    Ramuhalli, P.; Bond, L. J.; Griffin, J.; Henager, C.; Dixit, M.

    2011-06-01

    A central issue in life extension for the current fleet of light water nuclear power reactors (LWR) is the early detection and monitoring of significant materials degradation. To meet this need, nondestructive methods that are suitable for continuous monitoring over extended time periods (months to years) are needed. A related issue is the ability to estimate remaining useful life (RUL) of components and systems based on condition assessment or degradation information. Monitoring for early detection of materials degradation requires novel sensors and enhanced data integration techniques. A range of acoustic and electromagnetic measurement methods may be suitable, including acoustic microscopy, eddy current and magnetic Barkhausen emission. Prognostic methods that predict rate of degradation and remaining life based on phenomena that can be described by linear elastic fracture mechanics have been reported by several researchers. However, the challenge of predicting remaining life starting from earlier phases of degradation is largely unsolved. This paper discusses an assessment of selected diagnostic techniques, and the application of Bayesian prognostic algorithms to detection of early degradation and rate of degradation/life prediction. Such measurement and modeling methods are expected to form the basis for a new range of advanced diagnostic and prognostic approaches for assessing and monitoring life extension of ageing light water reactors.

  9. Similar estimates of population genetic composition and sex ratio derived from carcasses and faeces of Eurasian otter Lutra lutra.

    PubMed

    Dallas, John F; Coxon, Karen E; Sykes, Tim; Chanin, Paul R F; Marshall, Freda; Carss, David N; Bacon, Philip J; Piertney, Stuart B; Racey, Paul A

    2003-01-01

    Collecting faeces is viewed as a potentially efficient way to sample elusive animals. Nonetheless, any biases in estimates of population composition associated with such sampling remain uncharacterized. The goal of this study was to compare estimates of genetic composition and sex ratio derived from Eurasian otter Lutra lutra spraints (faeces) with estimates derived from carcasses. Twenty per cent of 426 wild-collected spraints from SW England yielded composite genotypes for 7-9 microsatellites and the SRY gene. The expected number of incorrect spraint genotypes was negligible, given the proportions of allele dropout and false allele detection estimated using paired blood and spraint samples of three captive otters. Fifty-two different spraint genotypes were detected and compared with genotypes of 70 otter carcasses from the same area. Carcass and spraint genotypes did not differ significantly in mean number of alleles, mean unbiased heterozygosity or sex ratio, although statistical power to detect all but large differences in sex ratio was low. The genetic compositions of carcass and spraint genotypes were very similar according to confidence intervals of theta and two methods for assigning composite genotypes to groups. A distinct group of approximately 11 carcass and spraint genotypes was detected using the latter methods. The results suggest that spraints can yield unbiased estimates of population genetic composition and sex ratio.

  10. Estimation of the stand ages of tropical secondary forests after shifting cultivation based on the combination of WorldView-2 and time-series Landsat images

    NASA Astrophysics Data System (ADS)

    Fujiki, Shogoro; Okada, Kei-ichi; Nishio, Shogo; Kitayama, Kanehiro

    2016-09-01

    We developed a new method to estimate stand ages of secondary vegetation in the Bornean montane zone, where local people conduct traditional shifting cultivation and protected areas are surrounded by patches of recovering secondary vegetation of various ages. Identifying stand ages at the landscape level is critical to improve conservation policies. We combined a high-resolution satellite image (WorldView-2) with time-series Landsat images. We extracted stand ages (the time elapsed since the most recent slash and burn) from a change-detection analysis with Landsat time-series images and superimposed the derived stand ages on the segments classified by object-based image analysis using WorldView-2. We regarded stand ages as a response variable, and object-based metrics as independent variables, to develop regression models that explain stand ages. Subsequently, we classified the vegetation of the target area into six age units and one rubber plantation unit (1-3 yr, 3-5 yr, 5-7 yr, 7-30 yr, 30-50 yr, >50 yr and 'rubber plantation') using regression models and linear discriminant analyses. Validation demonstrated an accuracy of 84.3%. Our approach is particularly effective in classifying highly dynamic pioneer vegetation younger than 7 years into 2-yr intervals, suggesting that rapid changes in vegetation canopies can be detected with high accuracy. The combination of a spectral time-series analysis and object-based metrics based on high-resolution imagery enabled the classification of dynamic vegetation under intensive shifting cultivation and yielded an informative land cover map based on stand ages.

  11. [Estimation of the biological age in taiga tick females (Ixodes persulcatus:Ixodidae) by the fat reserves in organism].

    PubMed

    Balashov, Iu S; Grigor'eva, L A

    2010-01-01

    The method of estimation of the biological age in non-feeding tick females by the level of adipose inclusions in the cells of the midgut and fat body is developed. In order to estimate the fat reserves in non-feeding females, alive ticks were dissected and fragments of their internal were vitally stained with the pregnant solution of sudan III in 70 % ethanol. Three age-specific groups were established: I, young females whose intestines and fat body were filled with fat inclusions; II, mature females whose fat reserves were partially expended; III, old females having isolated fat inclusions in their midgut and fat body.

  12. Do Individual Differences and Aging Effects in the Estimation of Geographical Slant Reflect Cognitive or Perceptual Effects?

    PubMed Central

    Dean, Abigail M.; Oh, Jaehyun; Thomson, Christopher J.; Norris, Catherine J.

    2016-01-01

    Several individual differences including age have been suggested to affect the perception of slant. A cross-sectional study of outdoor hill estimation (N = 106) was analyzed using individual difference measures of age, experiential knowledge, fitness, personality traits, and sex. Of particular note, it was found that for participants who reported any experiential knowledge about slant, estimates decreased (i.e., became more accurate) as conscientiousness increased, suggesting that more conscientious individuals were more deliberate about taking their experiential knowledge (rather than perception) into account. Effects of fitness were limited to those without experiential knowledge, suggesting that they, too, may be cognitive rather than perceptual. The observed effects of age, which tended to produce lower, more accurate estimates of hill slant, provide more evidence that older adults do not see hills as steeper. The main effect of age was to lower slant estimates; such effects may be due to implicit experiential knowledge acquired over a lifetime. The results indicate the impact of cognitive, rather than perceptual factors on individual differences in slant estimation. PMID:27698978

  13. Age estimation from pulp/tooth area ratio in maxillary incisors among Egyptians using dental radiographic images.

    PubMed

    Zaher, Jaklin Fekri; Fawzy, Irene Atef; Habib, Sahar Refaat; Ali, Magdy Mohamed

    2011-02-01

    Age estimation from dental radiographs is a non-destructive, simple method to obtain information. The aim of this study was to determine the reliability of age estimation from Egyptians' incisors radiographs. 144 periapical radiographs of maxillary (central & lateral) incisors (both sexes) aged 12-60 were used. Digital camera was used to image the radiographs. Images were computed and pulp/tooth area ratios were determined by AutoCAD Program. Data were subjected to correlation and regression analysis which showed statistically significant correlation (r = 0.23 &P = 0.006 for maxillary central incisors and r = -0.2 &P = 0.05 for maxillary lateral incisors) between age and pulp tooth area ratio. Linear regression equations were determined separately for both central and lateral incisors along with the corresponding Standard Error of Estimate, which ranged from 1.2 to 5.08 years. Consequently, it was concluded that pulp/tooth area ratios of incisors are reliable for estimation of age among Egyptians in forensic work.

  14. Evaluation of large area crop estimation techniques using LANDSAT and ground-derived data. [Missouri

    NASA Technical Reports Server (NTRS)

    Amis, M. L.; Lennington, R. K.; Martin, M. V.; Mcguire, W. G.; Shen, S. S. (Principal Investigator)

    1981-01-01

    The results of the Domestic Crops and Land Cover Classification and Clustering study on large area crop estimation using LANDSAT and ground truth data are reported. The current crop area estimation approach of the Economics and Statistics Service of the U.S. Department of Agriculture was evaluated in terms of the factors that are likely to influence the bias and variance of the estimator. Also, alternative procedures involving replacements for the clustering algorithm, the classifier, or the regression model used in the original U.S. Department of Agriculture procedures were investigated.

  15. Derivation of an Age and Weight Handicap for the 5K Run

    ERIC Educational Resources Information Center

    Vanderburgh, Paul M.; Laubach, Lloyd L.

    2007-01-01

    The adverse effect of increasing age and/or body weight on distance run performance has been well documented. Accordingly, nearly all five kilometer (5K) road races employ age categories and, sometimes, a heavier body weight classification. Problems with such conventions include small numbers of runners within older age categories and the…

  16. Mean Ages of Stratospheric Air Derived From in Situ Observations of CO2, CH4, and N2O

    NASA Technical Reports Server (NTRS)

    Andrews, A. E.; Boering, K. A.; Daube, B. C.; Wofsy, S. C.; Loewenstein, M.; Jost, H.; Podolske, J. R.; Webster, C. R.; Herman, R. L.; Scott, D. C.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Accurate mean ages for stratospheric air have been derived from a spatially and temporally comprehensive set of in situ observations of CO2, CH4, and N2O obtained from 1992 to 1998 from the NASA ER-2 aircraft and balloon flights. Errors associated with the tropospheric CO2 seasonal cycle and interannual variations in the CO2 growth rate are less than 0.5 year throughout the stratosphere and less than 0.3 year for air older than 2 years (N2O less than 275 ppbv), indicating that the age spectra are broad enough to attenuate these influences over the time period covered by these observations. The distribution of mean age with latitude and altitude provides detailed, quantitative information about the general circulation of the stratosphere. At 20 km, sharp meridional gradients in the mean age are observed across the subtropics. Between 20 and 30 km, the average difference in mean age between the tropics and midlatitudes is approximately 2 years, with slightly smaller differences at higher and lower altitudes. The mean age in the midlatitude middle stratosphere (approx. 25-32 km) is relatively constant with respect to altitude at 5 plus or minus 0.5 years. Comparison with earlier balloon observations of CO2 dating back to the 1970s indicates that the mean age of air in this region has remained within 11 year of its current value over the last 25 years. A climatology of mean age is derived from the observed compact relationship between mean age and N2O. These characteristics of the distribution of mean age in the stratosphere will serve as critically needed diagnostics for models of stratospheric transport.

  17. Estimating the brain pathological age of Alzheimer’s disease patients from MR image data based on the separability distance criterion

    NASA Astrophysics Data System (ADS)

    Li, Yongming; Li, Fan; Wang, Pin; Zhu, Xueru; Liu, Shujun; Qiu, Mingguo; Zhang, Jingna; Zeng, Xiaoping

    2016-10-01

    Traditional age estimation methods are based on the same idea that uses the real age as the training label. However, these methods ignore that there is a deviation between the real age and the brain age due to accelerated brain aging. This paper considers this deviation and searches for it by maximizing the separability distance value rather than by minimizing the difference between the estimated brain age and the real age. Firstly, set the search range of the deviation as the deviation candidates according to prior knowledge. Secondly, use the support vector regression (SVR) as the age estimation model to minimize the difference between the estimated age and the real age plus deviation rather than the real age itself. Thirdly, design the fitness function based on the separability distance criterion. Fourthly, conduct age estimation on the validation dataset using the trained age estimation model, put the estimated age into the fitness function, and obtain the fitness value of the deviation candidate. Fifthly, repeat the iteration until all the deviation candidates are involved and get the optimal deviation with maximum fitness values. The real age plus the optimal deviation is taken as the brain pathological age. The experimental results showed that the separability was apparently improved. For normal control-Alzheimer’s disease (NC-AD), normal control-mild cognition impairment (NC-MCI), and MCI-AD, the average improvements were 0.178 (35.11%), 0.033 (14.47%), and 0.017 (39.53%), respectively. For NC-MCI-AD, the average improvement was 0.2287 (64.22%). The estimated brain pathological age could be not only more helpful to the classification of AD but also more precisely reflect accelerated brain aging. In conclusion, this paper offers a new method for brain age estimation that can distinguish different states of AD and can better reflect the extent of accelerated aging.

  18. A New Method for Radar Rainfall Estimation Using Merged Radar and Gauge Derived Fields

    NASA Astrophysics Data System (ADS)

    Hasan, M. M.; Sharma, A.; Johnson, F.; Mariethoz, G.; Seed, A.

    2014-12-01

    Accurate estimation of rainfall is critical for any hydrological analysis. The advantage of radar rainfall measurements is their ability to cover large areas. However, the uncertainties in the parameters of the power law, that links reflectivity to rainfall intensity, have to date precluded the widespread use of radars for quantitative rainfall estimates for hydrological studies. There is therefore considerable interest in methods that can combine the strengths of radar and gauge measurements by merging the two data sources. In this work, we propose two new developments to advance this area of research. The first contribution is a non-parametric radar rainfall estimation method (NPZR) which is based on kernel density estimation. Instead of using a traditional Z-R relationship, the NPZR accounts for the uncertainty in the relationship between reflectivity and rainfall intensity. More importantly, this uncertainty can vary for different values of reflectivity. The NPZR method reduces the Mean Square Error (MSE) of the estimated rainfall by 16 % compared to a traditionally fitted Z-R relation. Rainfall estimates are improved at 90% of the gauge locations when the method is applied to the densely gauged Sydney Terrey Hills radar region. A copula based spatial interpolation method (SIR) is used to estimate rainfall from gauge observations at the radar pixel locations. The gauge-based SIR estimates have low uncertainty in areas with good gauge density, whilst the NPZR method provides more reliable rainfall estimates than the SIR method, particularly in the areas of low gauge density. The second contribution of the work is to merge the radar rainfall field with spatially interpolated gauge rainfall estimates. The two rainfall fields are combined using a temporally and spatially varying weighting scheme that can account for the strengths of each method. The weight for each time period at each location is calculated based on the expected estimation error of each method

  19. Application of isotopes to estimate water ages in variable time scales in surface and groundwaters

    NASA Astrophysics Data System (ADS)

    Kralik, Martin

    2014-05-01

    Water-Isotopes (2H, 3H, 18O) are ideal tracers not only to determine the origin of waters in precipitation, surface water (river + lakes) as well as in groundwater close to the surface and in deep groundwater but also the mean residence time (MRT) in many applied projects as drinking water supply, hydroelectric power plants, road tunnels etc. . Their application has a long history, but must be always evaluated by a feasible hydrogeological concept and/or other isotope and geochemical tracers. In Alpine areas the retention of precipitation in form of snow and ice in the winter half year is indicated by the lowest 18O-values. The snow melt of the highest part of the recharge area is marked by the lowest 18O-values in the river water, but may not coincide with the maximum flow. Time-series of precipitation station in the mountain and on river station indicate the arrival of the peak snow-melt water in the river and in Low-land areas 4-7 month later. Tritium series indicate that MRTs of several Austrian rivers are in the range of 4 - 6 years. The seasonal input variation of in 18O in precipitation and/or river waters can be used to calculate by lumped parameter models MRT of groundwater at a certain well and compare it with lysimeter measurements and transient model simulations. The MRT of the dispersion model is in good agreement with the estimated time calculated by the numerical transport model and the vertical lysimeter measurements. The MRT of spring water was studied by several methods (3H/3He, SF6 and 85Kr) and a long time series of 3H-measurements. The gas tracers are in good agreement in the range of 6-10 year whereas the 3H-series model (dispersion model) indicate ages in the range of 18-23 years. The hydrogeological concept indicate that the precipitation infiltrates in a mountainous karst area, but the transfer into the porous aquifer in the Vienna Basin occurs either through rivers draining away in the basin or through the lateral transport from the karst

  20. Models for estimating the metabolic syndrome biological age as the new index for evaluation and management of metabolic syndrome

    PubMed Central

    Kang, Young Gon; Suh, Eunkyung; Chun, Hyejin; Kim, Sun-Hyun; Kim, Deog Ki; Bae, Chul-Young

    2017-01-01

    Purpose This study aims to propose a metabolic syndrome (MS) biological age model, through which overall evaluation and management of the health status and aging state in MS can be done easily. Through this model, we hope to provide a novel evaluation and management health index that can be utilized in various health care fields. Patient and methods MS parameters from American Heart Association/National Heart, Lung, and Blood Institute guidelines in 2005 were used as biomarkers for the estimation of MS biological age. MS biological age model development was done by analyzing data of 263,828 participants and clinical application of the developed MS biological age was assessed by analyzing the data of 188,886 subjects. Results The principal component accounted for 36.1% in male and 38.9% in female of the total variance in the battery of five variables. The correlation coefficient between corrected biological age and chronological age in males and females were 0.711 and 0.737, respectively. Significant difference for mean MS biological age and chronological age between the three groups, normal, at risk and MS, was seen (P<0.001). Conclusion For the comprehensive approach in MS management, MS biological age is expected to be additionally utilized as a novel evaluation and management index along with the traditional MS diagnosis. PMID:28203066

  1. A comparison of consumptive-use estimates derived from the simplified surface energy balance approach and indirect reporting methods

    USGS Publications Warehouse

    Maupin, Molly A.; Senay, Gabriel B.; Kenny, Joan F.; Savoca, Mark E.

    2012-01-01

    Recent advances in remote-sensing technology and Simplified Surface Energy Balance (SSEB) methods can provide accurate and repeatable estimates of evapotranspiration (ET) when used with satellite observations of irrigated lands. Estimates of ET are generally considered equivalent to consumptive use (CU) because they represent the part of applied irrigation water that is evaporated, transpired, or otherwise not available for immediate reuse. The U.S. Geological Survey compared ET estimates from SSEB methods to CU data collected for 1995 using indirect methods as part of the National Water Use Information Program (NWUIP). Ten-year (2000-2009) average ET estimates from SSEB methods were derived using Moderate Resolution Imaging Spectroradiometer (MODIS) 1-kilometer satellite land surface temperature and gridded weather datasets from the Global Data Assimilation System (GDAS). County-level CU estimates for 1995 were assembled and referenced to 1-kilometer grid cells to synchronize with the SSEB ET estimates. Both datasets were seasonally and spatially weighted to represent the irrigation season (June-September) and those lands that were identified in the county as irrigated. A strong relation (R2 greater than 0.7) was determined between NWUIP CU and SSEB ET data. Regionally, the relation is stronger in arid western states than in humid eastern states, and positive and negative biases are both present at state-level comparisons. SSEB ET estimates can play a major role in monitoring and updating county-based CU estimates by providing a quick and cost-effective method to detect major year-to-year changes at county levels, as well as providing a means to disaggregate county-based ET estimates to sub-county levels. More research is needed to identify the causes for differences in state-based relations.

  2. Meta-analysis for deriving age- and gender-specific dose-response relationships between urinary cadmium concentration and {beta} {sub 2}-microglobulinuria under environmental exposure

    SciTech Connect

    Gamo, Masashi . E-mail: masashi-gamo@aist.go.jp; Ono, Kyoko; Nakanishi, Junko

    2006-05-15

    A meta-analysis was conducted to derive age- and gender-specific dose-response relationships between urinary cadmium (Cd) concentration and {beta} {sub 2}-microglobulinuria ({beta}2MG-uria) under environmental exposure. {beta}2MG-uria was defined by a cutoff point of 1000 {mu}g {beta} {sub 2}-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 {beta}2MG-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 {beta}2MG-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 {beta}2MG-uria. This was estimated to be approximately 3 {mu}g/g creatinine for a population in a small geographical area and approximately 2 {mu}g/g creatinine for a nationwide population.

  3. Differences in geriatric anthropometric data between DXA-based subject-specific estimates and non-age-specific traditional regression models.

    PubMed

    Chambers, April J; Sukits, Alison L; McCrory, Jean L; Cham, Rakie

    2011-08-01

    Age, obesity, and gender can have a significant impact on the anthropometrics of adults aged 65 and older. The aim of this study was to investigate differences in body segment parameters derived using two methods: (1) a dual-energy x-ray absorptiometry (DXA) subject-specific method (Chambers et al., 2010) and (2) traditional regression models (de Leva, 1996). The impact of aging, gender, and obesity on the potential differences between these methods was examined. Eighty-three healthy older adults were recruited for participation. Participants underwent a whole-body DXA scan (Hologic QDR 1000/W). Mass, length, center of mass, and radius of gyration were determined for each segment. In addition, traditional regressions were used to estimate these parameters (de Leva, 1996). A mixed linear regression model was performed (α = 0.05). Method type was significant in every variable of interest except forearm segment mass. The obesity and gender differences that we observed translate into differences associated with using traditional regressions to predict anthropometric variables in an aging population. Our data point to a need to consider age, obesity, and gender when utilizing anthropometric data sets and to develop regression models that accurately predict body segment parameters in the geriatric population, considering gender and obesity.

  4. An EPR method for estimating activity of antioxidants in mouse skin using an anthralin-derived radical model.

    PubMed

    Kawai, Sayo; Matsumoto, Ken-Ichiro; Utsumi, Hideo

    2010-03-01

    Inhibitory effects of intravenously or orally administered antioxidants on the anthralin-derived radical generated in skin (mainly in the epidermis) of living mice by ultraviolet-A (UVA) irradiation were estimated. Anthralin was applied to the dorsal skin of living mice and the mice were then exposed to UVA. The EPR signal intensity in skin tissue strips obtained from mice after anthralin-UVA treatment was measured by an X-band EPR spectrometer. Several common antioxidants such as ascorbate, glutathione and Trolox (a vitamin E analogue) intravenously administered to mice reduced anthralin-derived radical generation. Trolox showed the most prolonged and powerful effect. Intravenous injection of a clinically used cerebral neuroprotective drug, Edarabone (Radicut), also showed depletion for the anthralin-derived radical. Oral administration of a commercialized nutritional supplement (a cocktail of 17 herbals and vitamins) also attenuated the anthralin-derived radical. The anthralin-UVA treatment model for antioxidant activity in the epidermis is a potentially feasible method to estimate activity of antioxidants in the body.

  5. Estimating the lifetime economic burden of stroke according to the age of onset in South Korea: a cost of illness study

    PubMed Central

    2011-01-01

    Background The recently-observed trend towards younger stroke patients in Korea raises economic concerns, including erosion of the workforce. We compared per-person lifetime costs of stroke according to the age of stroke onset from the Korean societal perspective. Methods A state-transition Markov model consisted of three health states ('post primary stroke event', 'alive post stroke', and 'dead') was developed to simulate the natural history of stroke. The transition probabilities for fatal and non-fatal recurrent stroke by age and gender and for non-stroke causes of death were derived from the national epidemiologic data of the Korean Health Insurance Review and Assessment Services and data from the Danish Monitoring Trends in Cardiovascular Disease study. We used an incidence-based approach to estimate the long-term costs of stroke. The model captured stroke-related costs including costs within the health sector, patients' out-of-pocket costs outside the health sector, and costs resulting from loss of productivity due to morbidity and premature death using a human capital approach. Average insurance-covered costs occurring within the health sector were estimated from the National Health Insurance claims database. Other costs were estimated based on the national epidemiologic data and literature. All costs are presented in 2008 Korean currency values (Korean won = KRW). Results The lifetime costs of stroke were estimated to be: 200.7, 81.9, and 16.4 million Korean won (1,200 KRW is approximately equal to one US dollar) for men who suffered a first stroke at age 45, 55 and 65 years, respectively, and 75.7, 39.2, and 19.3 million KRW for women at the same age. While stroke occurring among Koreans aged 45 to 64 years accounted for only 30% of the total disease incidence, this age group incurred 75% of the total national lifetime costs of stroke. Conclusions A higher lifetime burden and increasing incidence of stroke among younger Koreans highlight the need for more

  6. Statistical methods to adjust for date and age misreporting to improve estimates of vital rates in Pakistan.

    PubMed

    Pullum, T W

    1991-02-01

    Misreporting of dates and ages poses serious difficulties for the estimation of the age distribution and birth and death rates in many developing countries. The pervasiveness of these problems is illustrated with data from a well-designed on-going survey in Pakistan, the Pakistan Demographic Survey. Methods for reconciling discrepancies, based on the assumptions of constant misreporting and survivorship patterns, are presented. The reasoning behind these methods could be applied much more generally. Research into the cultural interpretations of age and dates, and the nature of possible biases, is called for.

  7. Using GC × GC-FID profiles to estimate the age of weathered gasoline samples.

    PubMed

    Zorzetti, Brianne M; Harynuk, James J

    2011-11-01

    Predicting the amount of time that a petroleum mixture has been exposed to weathering effects has applications in areas of environmental and other forensic investigations, such as aiding in determining the cause and intent of a fire. Historically, research on the evaporation rates of hydrocarbon mixtures has focused on forensic oil spill identification and predicting if a fresh sample could be weathered to give an observed composition in an aged sample. Relatively little attention has focused on approaching the problem from the other direction: estimating exposure time based on the observed composition of a weathered sample at a given time and assuming a prior composition. Here, we build upon our previous research into the weathering of model mixtures by extending our work to gasoline. Samples of gasoline with varying octane ratings and from several vendors were weathered under controlled conditions and their composition monitored over time by two-dimensional gas chromatography (GC × GC). A variety of chemometric models were explored, including partial least squares (PLS), nonlinear PLS (PolyPLS) and locally weighted regression (LWR). A hierarchical application of multivariate techniques was able to predict the time for which a sample had been exposed to evaporative weathering. Partial least squares discriminant analysis could predict whether a sample was relatively fresh (<12 h exposure time) or highly weathered (>20 h exposure time). Subsequent regression models for these classes were evaluated for accuracy using the root mean square error of prediction. LWR was the most successful, whereby fresh and highly weathered samples were predicted to within 30 min and 5 h of exposure, respectively.

  8. Evaluation of precipitation estimates over CONUS derived from satellite, radar, and rain gauge datasets (2002-2012)

    NASA Astrophysics Data System (ADS)

    Prat, O. P.; Nelson, B. R.

    2014-10-01

    We use a suite of quantitative precipitation estimates (QPEs) derived from satellite, radar, and surface observations to derive precipitation characteristics over CONUS for the period 2002-2012. This comparison effort includes satellite multi-sensor datasets (bias-adjusted TMPA 3B42, near-real time 3B42RT), radar estimates (NCEP Stage IV), and rain gauge observations. Remotely sensed precipitation datasets are compared with surface observations from the Global Historical Climatology Network (GHCN-Daily) and from the PRISM (Parameter-elevation Regressions on Independent Slopes Model). The comparisons are performed at the annual, seasonal, and daily scales over the River Forecast Centers (RFCs) for CONUS. Annual average rain rates present a satisfying agreement with GHCN-D for all products over CONUS (± 6%). However, differences at the RFC are more important in particular for near-real time 3B42RT precipitation estimates (-33 to +49%). At annual and seasonal scales, the bias-adjusted 3B42 presented important improvement when compared to its near real time counterpart 3B42RT. However, large biases remained for 3B42 over the Western US for higher average accumulation (≥ 5 mm day-1) with respect to GHCN-D surface observations. At the daily scale, 3B42RT performed poorly in capturing extreme daily precipitation (> 4 in day-1) over the Northwest. Furthermore, the conditional analysis and the contingency analysis conducted illustrated the challenge of retrieving extreme precipitation from remote sensing estimates.

  9. Estimates of genetic parameters for total milk yield over multiple ages in Brazilian Murrah buffaloes using different models.

    PubMed

    Sesana, R C; Baldi, F; Borquis, R R A; Bignardi, A B; Hurtado-Lugo, N A; El Faro, L; Albuquerque, L G; Tonhati, H

    2014-04-14

    The objective of this study was to estimate variance components and genetic parameters for accumulated 305-day milk yield (MY305) over multiple ages, from 24 to 120 months of age, applying random regression (RRM), repeatability (REP) and multi-trait (MT) models. A total of 4472 lactation records from 1882 buffaloes of the Murrah breed were utilized. The contemporary group (herd-year-calving season) and number of milkings (two levels) were considered as fixed effects in all models. For REP and RRM, additive genetic, permanent environmental and residual effects were included as random effects. MT considered the same random effects as did REP and RRM with the exception of permanent environmental effect. Residual variances were modeled by a step function with 1, 4, and 6 classes. The heritabilities estimated with RRM increased with age, ranging from 0.19 to 0.34, and were slightly higher than that obtained with the REP model. For the MT model, heritability estimates ranged from 0.20 (37 months of age) to 0.32 (94 months of age). The genetic correlation estimates for MY305 obtained by RRM (L23.res4) and MT models were very similar, and varied from 0.77 to 0.99 and from 0.77 to 0.99, respectively. The rank correlation between breeding values for MY305 at different ages predicted by REP, MT, and RRM were high. It seems that a linear and quadratic Legendre polynomial to model the additive genetic and animal permanent environmental effects, respectively, may be sufficient to explain more parsimoniously the changes in MY305 genetic variation with age.

  10. Estimates of North American summertime planetary boundary layer depths derived from space-borne lidar

    NASA Astrophysics Data System (ADS)

    McGrath-Spangler, Erica L.; Denning, A. Scott

    2012-08-01

    The planetary boundary layer (PBL) mediates exchanges of energy, moisture, momentum, carbon, and pollutants between the surface and the atmosphere. This paper is a first step in producing a space-based estimate of PBL depth that can be used to compare with and evaluate model-based PBL depth retrievals, inform boundary layer studies, and improve understanding of the above processes. In clear sky conditions, space-borne lidar backscatter is frequently affected by atmospheric properties near the PBL top. Spatial patterns of 5-year mean mid-day summertime PBL depths over North America were estimated from the CALIPSO lidar backscatter and are generally consistent with model reanalyses and AMDAR (Aircraft Meteorological DAta Reporting) estimates. The rate of retrieval is greatest over the subtropical oceans (near 100%) where overlying subsidence limits optically thick clouds from growing and attenuating the lidar signal. The general retrieval rate over land is around 50% with decreased rates over the Southwestern United States and regions with high rates of convection. The lidar-based estimates of PBL depth tend to be shallower than aircraft estimates in coastal areas. Compared to reanalysis products, lidar PBL depths are greater over the oceans and areas of the boreal forest and shallower over the arid and semiarid regions of North America.

  11. Derivation of a Provisional, Age-dependent, AIS2+ Thoracic Risk Curve for the THOR50 Test Dummy via Integration of NASS Cases, PMHS Tests, and Simulation Data.

    PubMed

    Laituri, Tony R; Henry, Scott; El-Jawahri, Raed; Muralidharan, Nirmal; Li, Guosong; Nutt, Marvin

    2015-11-01

    A provisional, age-dependent thoracic risk equation (or, "risk curve") was derived to estimate moderate-to-fatal injury potential (AIS2+), pertaining to men with responses gaged by the advanced mid-sized male test dummy (THOR50). The derivation involved two distinct data sources: cases from real-world crashes (e.g., the National Automotive Sampling System, NASS) and cases involving post-mortem human subjects (PMHS). The derivation was therefore more comprehensive, as NASS datasets generally skew towards younger occupants, and PMHS datasets generally skew towards older occupants. However, known deficiencies had to be addressed (e.g., the NASS cases had unknown stimuli, and the PMHS tests required transformation of known stimuli into THOR50 stimuli). For the NASS portion of the analysis, chest-injury outcomes for adult male drivers about the size of the THOR50 were collected from real-world, 11-1 o'clock, full-engagement frontal crashes (NASS, 1995-2012 calendar years, 1985-2012 model-year light passenger vehicles). The screening for THOR50-sized men involved application of a set of newly-derived "correction" equations for self-reported height and weight data in NASS. Finally, THOR50 stimuli were estimated via field simulations involving attendant representative restraint systems, and those stimuli were then assigned to corresponding NASS cases (n=508). For the PMHS portion of the analysis, simulation-based closure equations were developed to convert PMHS stimuli into THOR50 stimuli. Specifically, closure equations were derived for the four measurement locations on the THOR50 chest by cross-correlating the results of matched-loading simulations between the test dummy and the age-dependent, Ford Human Body Model. The resulting closure equations demonstrated acceptable fidelity (n=75 matched simulations, R2≥0.99). These equations were applied to the THOR50-sized men in the PMHS dataset (n=20). The NASS and PMHS datasets were combined and subjected to survival

  12. The evaluation of age-related histomorphometric variables in a cadaver sample of lower socioeconomic status: implications for estimating age at death.

    PubMed

    Keough, N; L'Abbé, E N; Steyn, M

    2009-10-30

    Estimating age at death from adult skeletal remains is a daunting task for human osteologists. For this reason, the evaluation of micro-structural changes in bone with advancing age has become a popular method. However, factors such as nutrition, chronic disease, population group and sex have been suggested to influence the rate of bone turnover, and thus the use of histological methods in providing an accurate age at death has been questioned. The purpose of this study was to evaluate the accuracy and repeatability of 10 histomorphometric traits used to estimate age. The sample comprised of 146 dissection room cadavers of known sex, age and ancestry (105 males and 41 females). A 0.2cmx1.0cm sample was removed from the anterior surface of the mid-shaft of the femur (opposite the linea aspera), and slides were prepared according to standard methodology. The total osteon count (r=0.50), the percentage unremodelled bone (r=-0.50), the total number of non-Haversian canals (r=-0.50) and the average percentage of fragmental bone (r=0.55) had moderate correlations with age, while the total number of measurable osteons (r=0.43), the total number of osteonal fragments (r=0.40), the percentage of fragmentary bone (r=0.37) the average number of lamellae per osteon (r=0.29), the minimum diameter of the Haversian canals (r=0.14) and resorption spaces (r=0.11) had little to no relationship with age. Despite poor correlations with age, eight variables were shown to be highly repeatable (r=0.74-0.93). Moderate to low correlations with age may be attributed to these variables not being related to age in a progressive and predictable fashion, activity patterns or possible chronic disease in the sample. A databank needs to be compiled from larger samples from various populations in order to more holistically assess the relationship between these variables and age as well as other mitigating factors such as disease, nutrition and population group.

  13. Learning Multiple Band-Pass Filters for Sleep Stage Estimation: Towards Care Support for Aged Persons

    NASA Astrophysics Data System (ADS)

    Takadama, Keiki; Hirose, Kazuyuki; Matsushima, Hiroyasu; Hattori, Kiyohiko; Nakajima, Nobuo

    This paper proposes the sleep stage estimation method that can provide an accurate estimation for each person without connecting any devices to human's body. In particular, our method learns the appropriate multiple band-pass filters to extract the specific wave pattern of heartbeat, which is required to estimate the sleep stage. For an accurate estimation, this paper employs Learning Classifier System (LCS) as the data-mining techniques and extends it to estimate the sleep stage. Extensive experiments on five subjects in mixed health confirm the following implications: (1) the proposed method can provide more accurate sleep stage estimation than the conventional method, and (2) the sleep stage estimation calculated by the proposed method is robust regardless of the physical condition of the subject.

  14. Improving regression-model-based streamwater constituent load estimates derived from serially correlated data

    NASA Astrophysics Data System (ADS)

    Aulenbach, Brent T.

    2013-10-01

    A regression-model based approach is a commonly used, efficient method for estimating streamwater constituent load when there is a relationship between streamwater constituent concentration and continuous variables such as streamwater discharge, season and time. A subsetting experiment using a 30-year dataset of daily suspended sediment observations from the Mississippi River at Thebes, Illinois, was performed to determine optimal sampling frequency, model calibration period length, and regression model methodology, as well as to determine the effect of serial correlation of model residuals on load estimate precision. Two regression-based methods were used to estimate streamwater loads, the Adjusted Maximum Likelihood Estimator (AMLE), and the composite method, a hybrid load estimation approach. While both methods accurately and precisely estimated loads at the model's calibration period time scale, precisions were progressively worse at shorter reporting periods, from annually to monthly. Serial correlation in model residuals resulted in observed AMLE precision to be significantly worse than the model calculated standard errors of prediction. The composite method effectively improved upon AMLE loads for shorter reporting periods, but required a sampling interval of at least 15-days or shorter, when the serial correlations in the observed load residuals were greater than 0.15. AMLE precision was better at shorter sampling intervals and when using the shortest model calibration periods, such that the regression models better fit the temporal changes in the concentration-discharge relationship. The models with the largest errors typically had poor high flow sampling coverage resulting in unrepresentative models. Increasing sampling frequency and/or targeted high flow sampling are more efficient approaches to ensure sufficient sampling and to avoid poorly performing models, than increasing calibration period length.

  15. Improving regression-model-based streamwater constituent load estimates derived from serially correlated data

    USGS Publications Warehouse

    Aulenbach, Brent T.

    2013-01-01

    A regression-model based approach is a commonly used, efficient method for estimating streamwater constituent load when there is a relationship between streamwater constituent concentration and continuous variables such as streamwater discharge, season and time. A subsetting experiment using a 30-year dataset of daily suspended sediment observations from the Mississippi River at Thebes, Illinois, was performed to determine optimal sampling frequency, model calibration period length, and regression model methodology, as well as to determine the effect of serial correlation of model residuals on load estimate precision. Two regression-based methods were used to estimate streamwater loads, the Adjusted Maximum Likelihood Estimator (AMLE), and the composite method, a hybrid load estimation approach. While both methods accurately and precisely estimated loads at the model’s calibration period time scale, precisions were progressively worse at shorter reporting periods, from annually to monthly. Serial correlation in model residuals resulted in observed AMLE precision to be significantly worse than the model calculated standard errors of prediction. The composite method effectively improved upon AMLE loads for shorter reporting periods, but required a sampling interval of at least 15-days or shorter, when the serial correlations in the observed load residuals were greater than 0.15. AMLE precision was better at shorter sampling intervals and when using the shortest model calibration periods, such that the regression models better fit the temporal changes in the concentration–discharge relationship. The models with the largest errors typically had poor high flow sampling coverage resulting in unrepresentative models. Increasing sampling frequency and/or targeted high flow sampling are more efficient approaches to ensure sufficient sampling and to avoid poorly performing models, than increasing calibration period length.

  16. Global fire emission estimates (2007-2012) derived from inversion of formaldehyde columns

    NASA Astrophysics Data System (ADS)

    Bauwens, Maite; Stavrakou, Trissevgeni; Müller, Jean-Francois; De Smedt, Isabelle; Van Roozendael, Michel

    2014-05-01

    Wildfires have a strong impact on the chemistry and composition of the atmosphere and the radiative forcing. The fire emission estimates bear, however, important uncertainties due to the limited amount of field measurements, uncertainties in satellite burned area products, as well as empirical relations used for fuel type allocations. Atmospheric inversions are an alternative approach that provides new independent constraints on the fire estimates. This method involves measurements of trace gases combined with atmospheric models, where optimization algorithms are used to minimize the discrepancy between the model and the observations by adjusting the emission estimates. In this communication, we present global emission estimates of non-methane volatile organic compounds (NMVOCs), inferred from inversion of formaldehyde (HCHO) columns retrieved from the Global Ozone Monitoring Experiment-2 (GOME-2) instrument (De Smedt et al., 2012). The IMAGESv2 global CTM provides the relationship between the emissions and the vertical columns. The Global Fire Emissions Database version 3 (GFEDv3, van der Werf et al., 2010) is used as a priori bottom-up inventory in the model. The agreement between formaldehyde columns calculated by the IMAGESv2 model and the formaldehyde columns from GOME-2 is optimized using the adjoint modelling technique (Stavrakou et al., 2009). The obtained top-down fire emission estimates between 2007 and 2012 are available at the GlobEmission data portal (http://www.globemission.eu) on a monthly basis and at 0.5°x0.5° spatial resolution. The emission estimates are evaluated against three independent emission inventories: GFEDv3 (van der Werf et al., 2010), GFAS (Kaiser et al., 2012) and FINN (Wiedinmyer et al., 2011). Furthermore, simulated CO columns over the fire-affected regions will be compared with CO columns retrieved from the IASI sensor (George et al., 2009).

  17. Is Greulich and Pyle standards of skeletal maturation applicable for age estimation in South Indian Andhra children?

    PubMed Central

    Mohammed, Rezwana Begum; Rao, Dola Srinivasa; Goud, Alampur Srinivas; Sailaja, S.; Thetay, Anshuj Ajay Rao; Gopalakrishnan, Meera

    2015-01-01

    Introduction: Now-a-day age determination has gained importance for various forensic and legal reasons. Skeletal age (SA) of a test population can be estimated by comparing with established standards of Greulich and Pyle (G-P). As this atlas has been prepared using data from upper-class children born between 1917 and 1942 in the USA and the applicability of these standards to contemporary populations has yet to be tested on Andhra children living in India. Hence, this study was aimed to assess the reliability of bone age calculated by G-P atlas in estimation of age in selected population. Materials and Methods: A total of 660 children (330 girls, 330 boys) between ages 9 and 20 years were randomly selected from outpatient Department of Oral Medicine in GITAM Dental College, Andhra Pradesh. Digital hand-wrist radiographs were obtained and assessed for SA using G-P atlas and the difference between estimated SA and chronological age (CA) were compared with paired t-test and Wilcoxon signed rank test. Results: G-P method underestimated the SA by 0.23 ± 1.53 years for boys and overestimated SA by 0.02 ± 2 years in girls and mild underestimation was noted in the total sample of about 0.1 ± 1.78 years. Spearman rank test showed significant correlation between SA and CA (r = 0.86; P < 0.001). Conclusion: This study concluded that G-P standards were reliable in assessing age in South Indian Andhra children of age 9–20 years with unknown CA. PMID:26229357

  18. Age estimation by pulp-to-tooth area ratio using cone-beam computed tomography: A preliminary analysis

    PubMed Central

    Rai, Arpita; Acharya, Ashith B.; Naikmasur, Venkatesh G.

    2016-01-01

    Background: Age estimation of living or deceased individuals is an important aspect of forensic sciences. Conventionally, pulp-to-tooth area ratio (PTR) measured from periapical radiographs have been utilized as a nondestructive method of age estimation. Cone-beam computed tomography (CBCT) is a new method to acquire three-dimensional images of the teeth in living individuals. Aims: The present study investigated age estimation based on PTR of the maxillary canines measured in three planes obtained from CBCT image data. Settings and Design: Sixty subjects aged 20–85 years were included in the study. Materials and Methods: For each tooth, mid-sagittal, mid-coronal, and three axial sections—cementoenamel junction (CEJ), one-fourth root level from CEJ, and mid-root—were assessed. PTR was calculated using AutoCAD software after outlining the pulp and tooth. Statistical Analysis Used: All statistical analyses were performed using an SPSS 17.0 software program. Results and Conclusions: Linear regression analysis showed that only PTR in axial plane at CEJ had significant age correlation (r = 0.32; P < 0.05). This is probably because of clearer demarcation of pulp and tooth outline at this level. PMID:28123269

  19. A tilting algorithm for the estimation of fractional age survival probabilities.

    PubMed

    Barz, Christiane; Müller, Alfred

    2012-04-01

    Life tables used in life insurance determine the age of death distribution only at integer ages. Therefore, actuaries make fractional age assumptions to interpolate between integer age values when they have to value payments that are not restricted to integer ages. Traditional fractional age assumptions as well as the fractional independence assumption are easy to apply but result in a non-intuitive overall shape of the force of mortality. Other approaches proposed either require expensive optimization procedures or produce many discontinuities. We suggest a new, computationally inexpensive algorithm to select the parameters within the LFM-family introduced by Jones and Mereu (Insur Math Econ 27:261-276, 2000). In contrast to previously suggested methods, our algorithm enforces a monotone force of mortality between integer ages if the mortality rates are monotone and keeps the number of discontinuities small.

  20. MODIS Cloud Optical Property Retrieval Uncertainties Derived from Pixel-Level Radiometric Error Estimates

    NASA Technical Reports Server (NTRS)

    Platnick, Steven; Wind, Galina; Xiong, Xiaoxiong

    2011-01-01

    MODIS retrievals of cloud optical thickness and effective particle radius employ a well-known VNIR/SWIR solar reflectance technique. For this type of algorithm, we evaluate the uncertainty in simultaneous retrievals of these two parameters to pixel-level (scene-dependent) radiometric error estimates as well as other tractable error sources.

  1. Hierarchical Bayesian Model (HBM) - Derived Estimates of Air Quality for 2007: Annual Report

    EPA Science Inventory

    This report describes EPA's Hierarchical Bayesian model generated (HBM) estimates of ozone (O3) and fine particulate matter (PM2.5 particles with aerodynamic diameter < 2.5 microns)concentrations throughout the continental United States during the 2007 calen...