A lognormal distribution of the lengths of terminal twigs on self-similar branches of elm trees.

PubMed

Koyama, Kohei; Yamamoto, Ken; Ushio, Masayuki

2017-01-11

Lognormal distributions and self-similarity are characteristics associated with a wide range of biological systems. The sequential breakage model has established a link between lognormal distributions and self-similarity and has been used to explain species abundance distributions. To date, however, there has been no similar evidence in studies of multicellular organismal forms. We tested the hypotheses that the distribution of the lengths of terminal stems of Japanese elm trees (Ulmus davidiana), the end products of a self-similar branching process, approaches a lognormal distribution. We measured the length of the stem segments of three elm branches and obtained the following results: (i) each occurrence of branching caused variations or errors in the lengths of the child stems relative to their parent stems; (ii) the branches showed statistical self-similarity; the observed error distributions were similar at all scales within each branch and (iii) the multiplicative effect of these errors generated variations of the lengths of terminal twigs that were well approximated by a lognormal distribution, although some statistically significant deviations from strict lognormality were observed for one branch. Our results provide the first empirical evidence that statistical self-similarity of an organismal form generates a lognormal distribution of organ sizes. © 2017 The Author(s).

Coronary artery calcium distributions in older persons in the AGES-Reykjavik study

PubMed Central

Gudmundsson, Elias Freyr; Gudnason, Vilmundur; Sigurdsson, Sigurdur; Launer, Lenore J.; Harris, Tamara B.; Aspelund, Thor

2013-01-01

Coronary Artery Calcium (CAC) is a sign of advanced atherosclerosis and an independent risk factor for cardiac events. Here, we describe CAC-distributions in an unselected aged population and compare modelling methods to characterize CAC-distribution. CAC is difficult to model because it has a skewed and zero inflated distribution with over-dispersion. Data are from the AGES-Reykjavik sample, a large population based study [2002-2006] in Iceland of 5,764 persons aged 66-96 years. Linear regressions using logarithmic- and Box-Cox transformations on CAC+1, quantile regression and a Zero-Inflated Negative Binomial model (ZINB) were applied. Methods were compared visually and with the PRESS-statistic, R2 and number of detected associations with concurrently measured variables. There were pronounced differences in CAC according to sex, age, history of coronary events and presence of plaque in the carotid artery. Associations with conventional coronary artery disease (CAD) risk factors varied between the sexes. The ZINB model provided the best results with respect to the PRESS-statistic, R2, and predicted proportion of zero scores. The ZINB model detected similar numbers of associations as the linear regression on ln(CAC+1) and usually with the same risk factors. PMID:22990371

Size distribution of dust grains: A problem of self-similarity

NASA Technical Reports Server (NTRS)

Henning, TH.; Dorschner, J.; Guertler, J.

1989-01-01

Distribution functions describing the results of natural processes frequently show the shape of power laws, e.g., mass functions of stars and molecular clouds, velocity spectrum of turbulence, size distributions of asteroids, micrometeorites and also interstellar dust grains. It is an open question whether this behavior is a result simply coming about by the chosen mathematical representation of the observational data or reflects a deep-seated principle of nature. The authors suppose the latter being the case. Using a dust model consisting of silicate and graphite grains Mathis et al. (1977) showed that the interstellar extinction curve can be represented by taking a grain radii distribution of power law type n(a) varies as a(exp -p) with 3.3 less than or equal to p less than or equal to 3.6 (example 1) as a basis. A different approach to understanding power laws like that in example 1 becomes possible by the theory of self-similar processes (scale invariance). The beta model of turbulence (Frisch et al., 1978) leads in an elementary way to the concept of the self-similarity dimension D, a special case of Mandelbrot's (1977) fractal dimension. In the frame of this beta model, it is supposed that on each stage of a cascade the system decays to N clumps and that only the portion beta N remains active further on. An important feature of this model is that the active eddies become less and less space-filling. In the following, the authors assume that grain-grain collisions are such a scale-invarient process and that the remaining grains are the inactive (frozen) clumps of the cascade. In this way, a size distribution n(a) da varies as a(exp -(D+1))da (example 2) results. It seems to be highly probable that the power law character of the size distribution of interstellar dust grains is the result of a self-similarity process. We can, however, not exclude that the process leading to the interstellar grain size distribution is not fragmentation at all. It could be, e

Age distribution patterns of human gene families: divergent for Gene Ontology categories and concordant between different subcellular localizations.

PubMed

Liu, Gangbiao; Zou, Yangyun; Cheng, Qiqun; Zeng, Yanwu; Gu, Xun; Su, Zhixi

2014-04-01

The age distribution of gene duplication events within the human genome exhibits two waves of duplications along with an ancient component. However, because of functional constraint differences, genes in different functional categories might show dissimilar retention patterns after duplication. It is known that genes in some functional categories are highly duplicated in the early stage of vertebrate evolution. However, the correlations of the age distribution pattern of gene duplication between the different functional categories are still unknown. To investigate this issue, we developed a robust pipeline to date the gene duplication events in the human genome. We successfully estimated about three-quarters of the duplication events within the human genome, along with the age distribution pattern in each Gene Ontology (GO) slim category. We found that some GO slim categories show different distribution patterns when compared to the whole genome. Further hierarchical clustering of the GO slim functional categories enabled grouping into two main clusters. We found that human genes located in the duplicated copy number variant regions, whose duplicate genes have not been fixed in the human population, were mainly enriched in the groups with a high proportion of recently duplicated genes. Moreover, we used a phylogenetic tree-based method to date the age of duplications in three signaling-related gene superfamilies: transcription factors, protein kinases and G-protein coupled receptors. These superfamilies were expressed in different subcellular localizations. They showed a similar age distribution as the signaling-related GO slim categories. We also compared the differences between the age distributions of gene duplications in multiple subcellular localizations. We found that the distribution patterns of the major subcellular localizations were similar to that of the whole genome. This study revealed the whole picture of the evolution patterns of gene functional

Estimating the Spatial Distribution of Groundwater Age Using Synoptic Surveys of Environmental Tracers in Streams

NASA Astrophysics Data System (ADS)

Gardner, W. P.

2017-12-01

A model which simulates tracer concentration in surface water as a function the age distribution of groundwater discharge is used to characterize groundwater flow systems at a variety of spatial scales. We develop the theory behind the model and demonstrate its application in several groundwater systems of local to regional scale. A 1-D stream transport model, which includes: advection, dispersion, gas exchange, first-order decay and groundwater inflow is coupled a lumped parameter model that calculates the concentration of environmental tracers in discharging groundwater as a function of the groundwater residence time distribution. The lumped parameters, which describe the residence time distribution, are allowed to vary spatially, and multiple environmental tracers can be simulated. This model allows us to calculate the longitudinal profile of tracer concentration in streams as a function of the spatially variable groundwater age distribution. By fitting model results to observations of stream chemistry and discharge, we can then estimate the spatial distribution of groundwater age. The volume of groundwater discharge to streams can be estimated using a subset of environmental tracers, applied tracers, synoptic stream gauging or other methods, and the age of groundwater then estimated using the previously calculated groundwater discharge and observed environmental tracer concentrations. Synoptic surveys of SF6, CFC's, 3H and 222Rn, along with measured stream discharge are used to estimate the groundwater inflow distribution and mean age for regional scale surveys of the Berland River in west-central Alberta. We find that groundwater entering the Berland has observable age, and that the age estimated using our stream survey is of similar order to limited samples from groundwater wells in the region. Our results show that the stream can be used as an easily accessible location to constrain the regional scale spatial distribution of groundwater age.

Potential effects of regional pumpage on groundwater age distribution

USGS Publications Warehouse

Zinn, Brendan A.; Konikow, Leonard F.

2007-01-01

Groundwater ages estimated from environmental tracers can help calibrate groundwater flow models. Groundwater age represents a mixture of traveltimes, with the distribution of ages determined by the detailed structure of the flow field, which can be prone to significant transient variability. Effects of pumping on age distribution were assessed using direct age simulation in a hypothetical layered aquifer system. A steady state predevelopment age distribution was computed first. A well field was then introduced, and pumpage caused leakage into the confined aquifer of older water from an overlying confining unit. Large changes in simulated groundwater ages occurred in both the aquifer and the confining unit at high pumping rates, and the effects propagated a substantial distance downgradient from the wells. The range and variance of ages contributing to the well increased substantially during pumping. The results suggest that the groundwater age distribution in developed aquifers may be affected by transient leakage from low‐permeability material, such as confining units, under certain hydrogeologic conditions.

Similarity of WISC-R and WAIS-R Scores at Age 16.

ERIC Educational Resources Information Center

Sandoval, Jonathan; And Others

1988-01-01

Examined similarity of scores of 30 learning disabled students (aged 16 and 17) on the Wechsler Intelligence Scale for Children-Revised (WISC-R) and the Wechsler Adult Intelligence Scale-Revised (WAIS-R). Results documented similarity between WISC-R and WAIS-R for 16 year-olds who were learning disabled and had average intellectual ability.…

Linking age, survival, and transit time distributions

NASA Astrophysics Data System (ADS)

Calabrese, Salvatore; Porporato, Amilcare

2015-10-01

Although the concepts of age, survival, and transit time have been widely used in many fields, including population dynamics, chemical engineering, and hydrology, a comprehensive mathematical framework is still missing. Here we discuss several relationships among these quantities by starting from the evolution equation for the joint distribution of age and survival, from which the equations for age and survival time readily follow. It also becomes apparent how the statistical dependence between age and survival is directly related to either the age dependence of the loss function or the survival-time dependence of the input function. The solution of the joint distribution equation also allows us to obtain the relationships between the age at exit (or death) and the survival time at input (or birth), as well as to stress the symmetries of the various distributions under time reversal. The transit time is then obtained as a sum of the age and survival time, and its properties are discussed along with the general relationships between their mean values. The special case of steady state case is analyzed in detail. Some examples, inspired by hydrologic applications, are presented to illustrate the theory with the specific results. This article was corrected on 11 Nov 2015. See the end of the full text for details.

Age of onset of recurrent respiratory papillomatosis: a distribution analysis.

PubMed

San Giorgi, M R M; van den Heuvel, E R; Tjon Pian Gi, R E A; Brunings, J W; Chirila, M; Friedrich, G; Golusinski, W; Graupp, M; Horcasitas Pous, R A; Ilmarinen, T; Jackowska, J; Koelmel, J C; Ferran Vilà, F; Weichbold, V; Wierzbicka, M; Dikkers, F G

2016-10-01

Distribution of age of onset of recurrent respiratory papillomatosis (RRP) is generally described to be bimodal, with peaks at approximately 5 years and 30 years. This assumption has never been scientifically confirmed, and authors tend to refer to an article that does not describe distribution. Knowledge of the distribution of age of onset is important for virological and epidemiological comprehension. The objective of this study was to determine the distribution of age of onset of RRP in a large international sample. Cross-sectional distribution analysis. Laryngologists from 12 European hospitals provided information on date of birth and date of onset of all their RRP patients treated between 1998 and 2012. Centers that exclusively treated either patients with juvenile onset RRP or patients with adult onset RRP, or were less accessible for one of these groups, were excluded to prevent skewness. A mixture model was implemented to describe distribution of age of onset. The best fitting model was selected using the Bayesian information criterion. Six hundred and thirty-nine patients were included in the analysis. Age of onset was described by a three component mixture distribution with lognormally distributed components. Recurrent respiratory papillomatosis starts at three median ages 7, 35 and 64 years. Distribution of age of onset of RRP shows three peaks. In addition to the already adopted idea of age peaks at paediatric and adult age, there is an additional peak around the age of 64. © 2015 John Wiley & Sons Ltd.

Age-Related Impairment on a Forced-Choice Version of the Mnemonic Similarity Task

PubMed Central

Huffman, Derek J.; Stark, Craig E. L.

2018-01-01

Previous studies from our lab have indicated that healthy older adults are impaired in their ability to mnemonically discriminate between previously viewed objects and similar lure objects in the Mnemonic Similarity Task (MST). These studies have used either old/similar/new or old/new test formats. The forced-choice test format (e.g., “Did you see object A or object A’ during the encoding phase?”) relies on different assumptions than the old/new test format (e.g., “Did you see this object during the encoding phase?”); hence, converging evidence from these approaches would bolster the conclusion that healthy aging is accompanied by impaired performance on the MST. Consistent with our hypothesis, healthy older adults exhibited impaired performance on a forced-choice test format that required discriminating between a target and a similar lure. We also tested the hypothesis that age-related impairments on the MST could be modeled within a global matching computational framework. We found that decreasing the probability of successful feature encoding in the models caused changes that were similar to the empirical data in healthy older adults. Collectively, our behavioral results extend to the forced-choice test format the finding that healthy aging is accompanied by an impaired ability to discriminate between targets and similar lures, and our modeling results suggest that a diminished probability of encoding stimulus features is a candidate mechanism for memory changes in healthy aging. We also discuss the ability of global matching models to account for findings in other studies that have used variants on mnemonic similarity tasks. PMID:28004951

Theoretical foundation for measuring the groundwater age distribution.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gardner, William Payton; Arnold, Bill Walter

2014-01-01

In this study, we use PFLOTRAN, a highly scalable, parallel, flow and reactive transport code to simulate the concentrations of 3H, 3He, CFC-11, CFC-12, CFC-113, SF6, 39Ar, 81Kr, 4He and themean groundwater age in heterogeneous fields on grids with an excess of 10 million nodes. We utilize this computational platform to simulate the concentration of multiple tracers in high-resolution, heterogeneous 2-D and 3-D domains, and calculate tracer-derived ages. Tracer-derived ages show systematic biases toward younger ages when the groundwater age distribution contains water older than the maximum tracer age. The deviation of the tracer-derived age distribution from the true groundwatermore » age distribution increases with increasing heterogeneity of the system. However, the effect of heterogeneity is diminished as the mean travel time gets closer the tracer age limit. Age distributions in 3-D domains differ significantly from 2-D domains. 3D simulations show decreased mean age, and less variance in age distribution for identical heterogeneity statistics. High-performance computing allows for investigation of tracer and groundwater age systematics in high-resolution domains, providing a platform for understanding and utilizing environmental tracer and groundwater age information in heterogeneous 3-D systems. Groundwater environmental tracers can provide important constraints for the calibration of groundwater flow models. Direct simulation of environmental tracer concentrations in models has the additional advantage of avoiding assumptions associated with using calculated groundwater age values. This study quantifies model uncertainty reduction resulting from the addition of environmental tracer concentration data. The analysis uses a synthetic heterogeneous aquifer and the calibration of a flow and transport model using the pilot point method. Results indicate a significant reduction in the uncertainty in permeability with the addition of environmental tracer data

Age-related impairment on a forced-choice version of the Mnemonic Similarity Task.

PubMed

Huffman, Derek J; Stark, Craig E L

2017-02-01

Previous studies from our lab have indicated that healthy older adults are impaired in their ability to mnemonically discriminate between previously viewed objects and similar lure objects in the Mnemonic Similarity Task (MST). These studies have used either old/similar/new or old/new test formats. The forced-choice test format (e.g., "Did you see object A or object A' during the encoding phase?") relies on different assumptions than the old/new test format (e.g., "Did you see this object during the encoding phase?"); hence, converging evidence from these approaches would bolster the conclusion that healthy aging is accompanied by impaired performance on the MST. Consistent with our hypothesis, healthy older adults exhibited impaired performance on a forced-choice test format that required discriminating between a target and a similar lure. We also tested the hypothesis that age-related impairments on the MST could be modeled within a global matching computational framework. We found that decreasing the probability of successful feature encoding in the models caused changes that were similar to the empirical data in healthy older adults. Collectively, our behavioral results using the forced-choice format extend the finding that healthy aging is accompanied by an impaired ability to discriminate between targets and similar lures, and our modeling results suggest that a diminished probability of encoding stimulus features is a candidate mechanism for memory changes in healthy aging. We also discuss the ability of global matching models to account for findings in other studies that have used variants on mnemonic similarity tasks. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Age distribution and age-related outcomes of olfactory neuroblastoma: a population-based analysis.

PubMed

Yin, Zhenzhen; Wang, Youyou; Wu, Yuemei; Zhang, Ximei; Wang, Fengming; Wang, Peiguo; Tao, Zhen; Yuan, Zhiyong

2018-01-01

The objective of the study was to describe the age distribution and to evaluate the role of prognostic value of age on survival in patients diagnosed with olfactory neuroblastoma (ONB). A population-based retrospective analysis was conducted. The population-based study of patients in the Surveillance, Epidemiology, and End Results (SEER) tumor registry, who were diagnosed with ONB from 1973 to 2014, were retrospectively analyzed. The cohort included 876 patients with a median age of 54 years. There was a unimodal distribution of age and ONBs most frequently occurred in the fifth to sixth decades of life. Kaplan-Meier analysis demonstrated overall survival (OS) and cancer-specific survival (CSS) rates of 69% and 78% at 5 years. Multivariable Cox regression analysis showed that age, SEER stage, and surgery were independent prognostic factors for CSS. The risk of overall death and cancer-specific death increased 3.1% and 1.6% per year, respectively. Patients aged >60 years presented significantly poor OS and CSS compared with patients aged ≤60 years, even in patients with loco-regional disease or in those treated with surgery. This study highlights the growing evidence that there is a unimodal age distribution of ONB and that age is an important adverse prognostic factor.

Social cognition in schizophrenia and healthy aging: differences and similarities.

PubMed

Silver, Henry; Bilker, Warren B

2014-12-01

Social cognition is impaired in schizophrenia but it is not clear whether this is specific for the illness and whether emotion perception is selectively affected. To study this we examined the perception of emotional and non-emotional clues in facial expressions, a key social cognitive skill, in schizophrenia patients and old healthy individuals using young healthy individuals as reference. Tests of object recognition, visual orientation, psychomotor speed, and working memory were included to allow multivariate analysis taking into account other cognitive functions Schizophrenia patients showed impairments in recognition of identity and emotional facial clues compared to young and old healthy groups. Severity was similar to that for object recognition and visuospatial processing. Older and younger healthy groups did not differ from each other on these tests. Schizophrenia patients and old healthy individuals were similarly impaired in the ability to automatically learn new faces during the testing procedure (measured by the CSTFAC index) compared to young healthy individuals. Social cognition is distinctly impaired in schizophrenia compared to healthy aging. Further study is needed to identify the mechanisms of automatic social cognitive learning impairment in schizophrenia patients and healthy aging individuals and determine whether similar neural systems are affected. Copyright © 2014 Elsevier B.V. All rights reserved.

Age-Related Skeletal Muscle Decline Is Similar in HIV-Infected and Uninfected Individuals

PubMed Central

Yarasheski, Kevin E.; Scherzer, Rebecca; Kotler, Donald P.; Dobs, Adrian S.; Tien, Phyllis C.; Lewis, Cora E.; Kronmal, Richard A.; Heymsfield, Steven B.; Bacchetti, Peter

2011-01-01

Background. Skeletal muscle (SM) mass decreases with advanced age and with disease in HIV infection. It is unknown whether age-related muscle loss is accelerated in the current era of antiretroviral therapy and which factors might contribute to muscle loss among HIV-infected adults. We hypothesized that muscle mass would be lower and decline faster in HIV-infected adults than in similar-aged controls. Methods. Whole-body 1H-magnetic resonance imaging was used to quantify regional and total SM in 399 HIV-infected and 204 control men and women at baseline and 5 years later. Multivariable regression identified associated factors. Results. At baseline and Year 5, total SM was lower in HIV-infected than control men. HIV-infected women were similar to control women at both time points. After adjusting for demographics, lifestyle factors, and total adipose tissue, HIV infection was associated with lower Year 5 SM in men and higher SM in women compared with controls. Average overall 5-year change in total SM was small and age related, but rate of change was similar in HIV-infected and control men and women. CD4 count and efavirenz use in HIV-infected participants were associated with increasing SM, whereas age and stavudine use were associated with decreasing SM. Conclusions. Muscle mass was lower in HIV-infected men compared with controls, whereas HIV-infected women had slightly higher SM than control women after multivariable adjustment. We found evidence against substantially faster SM decline in HIV infected versus similar-aged controls. SM gain was associated with increasing CD4 count, whereas stavudine use may contribute to SM loss. PMID:21310810

Age-related skeletal muscle decline is similar in HIV-infected and uninfected individuals.

PubMed

Yarasheski, Kevin E; Scherzer, Rebecca; Kotler, Donald P; Dobs, Adrian S; Tien, Phyllis C; Lewis, Cora E; Kronmal, Richard A; Heymsfield, Steven B; Bacchetti, Peter; Grunfeld, Carl

2011-03-01

Skeletal muscle (SM) mass decreases with advanced age and with disease in HIV infection. It is unknown whether age-related muscle loss is accelerated in the current era of antiretroviral therapy and which factors might contribute to muscle loss among HIV-infected adults. We hypothesized that muscle mass would be lower and decline faster in HIV-infected adults than in similar-aged controls. Whole-body (1)H-magnetic resonance imaging was used to quantify regional and total SM in 399 HIV-infected and 204 control men and women at baseline and 5 years later. Multivariable regression identified associated factors. At baseline and Year 5, total SM was lower in HIV-infected than control men. HIV-infected women were similar to control women at both time points. After adjusting for demographics, lifestyle factors, and total adipose tissue, HIV infection was associated with lower Year 5 SM in men and higher SM in women compared with controls. Average overall 5-year change in total SM was small and age related, but rate of change was similar in HIV-infected and control men and women. CD4 count and efavirenz use in HIV-infected participants were associated with increasing SM, whereas age and stavudine use were associated with decreasing SM. Muscle mass was lower in HIV-infected men compared with controls, whereas HIV-infected women had slightly higher SM than control women after multivariable adjustment. We found evidence against substantially faster SM decline in HIV infected versus similar-aged controls. SM gain was associated with increasing CD4 count, whereas stavudine use may contribute to SM loss.

Tree Age Distributions Reveal Large-Scale Disturbance-Recovery Cycles in Three Tropical Forests

PubMed Central

Vlam, Mart; van der Sleen, Peter; Groenendijk, Peter; Zuidema, Pieter A.

2017-01-01

Over the past few decades there has been a growing realization that a large share of apparently ‘virgin’ or ‘old-growth’ tropical forests carries a legacy of past natural or anthropogenic disturbances that have a substantial effect on present-day forest composition, structure and dynamics. Yet, direct evidence of such disturbances is scarce and comparisons of disturbance dynamics across regions even more so. Here we present a tree-ring based reconstruction of disturbance histories from three tropical forest sites in Bolivia, Cameroon, and Thailand. We studied temporal patterns in tree regeneration of shade-intolerant tree species, because establishment of these trees is indicative for canopy disturbance. In three large areas (140–300 ha), stem disks and increment cores were collected for a total of 1154 trees (>5 cm diameter) from 12 tree species to estimate the age of every tree. Using these age estimates we produced population age distributions, which were analyzed for evidence of past disturbance. Our approach allowed us to reconstruct patterns of tree establishment over a period of around 250 years. In Bolivia, we found continuous regeneration rates of three species and a peaked age distribution of a long-lived pioneer species. In both Cameroon and Thailand we found irregular age distributions, indicating strongly reduced regeneration rates over a period of 10–60 years. Past fires, windthrow events or anthropogenic disturbances all provide plausible explanations for the reported variation in tree age across the three sites. Our results support the recent idea that the long-term dynamics of tropical forests are impacted by large-scale disturbance-recovery cycles, similar to those driving temperate forest dynamics. PMID:28105034

Tree Age Distributions Reveal Large-Scale Disturbance-Recovery Cycles in Three Tropical Forests.

PubMed

Vlam, Mart; van der Sleen, Peter; Groenendijk, Peter; Zuidema, Pieter A

2016-01-01

Over the past few decades there has been a growing realization that a large share of apparently 'virgin' or 'old-growth' tropical forests carries a legacy of past natural or anthropogenic disturbances that have a substantial effect on present-day forest composition, structure and dynamics. Yet, direct evidence of such disturbances is scarce and comparisons of disturbance dynamics across regions even more so. Here we present a tree-ring based reconstruction of disturbance histories from three tropical forest sites in Bolivia, Cameroon, and Thailand. We studied temporal patterns in tree regeneration of shade-intolerant tree species, because establishment of these trees is indicative for canopy disturbance. In three large areas (140-300 ha), stem disks and increment cores were collected for a total of 1154 trees (>5 cm diameter) from 12 tree species to estimate the age of every tree. Using these age estimates we produced population age distributions, which were analyzed for evidence of past disturbance. Our approach allowed us to reconstruct patterns of tree establishment over a period of around 250 years. In Bolivia, we found continuous regeneration rates of three species and a peaked age distribution of a long-lived pioneer species. In both Cameroon and Thailand we found irregular age distributions, indicating strongly reduced regeneration rates over a period of 10-60 years. Past fires, windthrow events or anthropogenic disturbances all provide plausible explanations for the reported variation in tree age across the three sites. Our results support the recent idea that the long-term dynamics of tropical forests are impacted by large-scale disturbance-recovery cycles, similar to those driving temperate forest dynamics.

Similar age-dependent levothyroxine requirements of schoolchildren with congenital or acquired hypothyroidism.

PubMed

Perlsteyn, Martin; Deladoëy, Johnny; Van Vliet, Guy

2016-06-01

A recent study in children suggested that levothyroxine requirements are higher in congenital than in acquired hypothyroidism but did not match for severity of disease. Here, we studied only children with congenital or acquired hypothyroidism who had an undetectable fT4 at diagnosis. There were eight girls with congenital hypothyroidism due to athyreosis and eight girls with acquired hypothyroidism due to autoimmune thyroid disease. The median levothyroxine dose received at the most recent visit when serum TSH was <5.0 mU/L (at a median age of 7.86 and 14.29 years, respectively) was 3.2 mcg/kg/day in the former and 2.4 mcg/kg/day in the latter (N.S.). Combining both groups, the levothyroxine requirement decreased by 0.5 mcg/kg/day for every 4-year period. When strictly matched for severity of disease, levothyroxine requirements are similar in school-age children with congenital or acquired hypothyroidism and decrease with age. Thus, in congenital hypothyroidism treated early with high-dose levothyroxine, pituitary resistance to thyroxine feedback does not appear to be present at school age. • Pediatric studies unmatched for severity have suggested that levothyroxine requirements are higher in congenital than in acquired hypothyroidism. What is new: • When strictly matched for severity, levothyroxine requirements are similar in children with congenital or acquired hypothyroidism and decrease with age.

Engaging the aging workforce: the relationship between perceived age similarity, satisfaction with coworkers, and employee engagement.

PubMed

Avery, Derek R; McKay, Patrick F; Wilson, David C

2007-11-01

Business publications and the popular press have stressed the importance of creating conditions for meaningful employee expression in work roles, also known as engagement. Few empirical studies, however, have examined how individual or situational factors relate to engagement. Consequently, this study examines the interplay between employee age, perceived coworker age composition, and satisfaction with older (older than 55) and younger (younger than 40) coworkers on engagement using a sample of 901 individuals employed in the United Kingdom. Results indicated that satisfaction with one's coworkers related significantly to engagement. Moreover, perceived age similarity was associated with higher levels of engagement among older workers when they were highly satisfied with their coworkers over 55 and lower levels of engagement when they were not. (c) 2007 APA

Predicting human age using regional morphometry and inter-regional morphological similarity

NASA Astrophysics Data System (ADS)

Wang, Xun-Heng; Li, Lihua

2016-03-01

The goal of this study is predicting human age using neuro-metrics derived from structural MRI, as well as investigating the relationships between age and predictive neuro-metrics. To this end, a cohort of healthy subjects were recruited from 1000 Functional Connectomes Project. The ages of the participations were ranging from 7 to 83 (36.17+/-20.46). The structural MRI for each subject was preprocessed using FreeSurfer, resulting in regional cortical thickness, mean curvature, regional volume and regional surface area for 148 anatomical parcellations. The individual age was predicted from the combination of regional and inter-regional neuro-metrics. The prediction accuracy is r = 0.835, p < 0.00001, evaluated by Pearson correlation coefficient between predicted ages and actual ages. Moreover, the LASSO linear regression also found certain predictive features, most of which were inter-regional features. The turning-point of the developmental trajectories in human brain was around 40 years old based on regional cortical thickness. In conclusion, structural MRI could be potential biomarkers for the aging in human brain. The human age could be successfully predicted from the combination of regional morphometry and inter-regional morphological similarity. The inter-regional measures could be beneficial to investigating human brain connectome.

Paleodemographic age-at-death distributions of two Mexican skeletal collections: a comparison of transition analysis and traditional aging methods.

PubMed

Bullock, Meggan; Márquez, Lourdes; Hernández, Patricia; Ruíz, Fernando

2013-09-01

Traditional methods of aging adult skeletons suffer from the problem of age mimicry of the reference collection, as described by Bocquet-Appel and Masset (1982). Transition analysis (Boldsen et al., 2002) is a method of aging adult skeletons that addresses the problem of age mimicry of the reference collection by allowing users to select an appropriate prior probability. In order to evaluate whether transition analysis results in significantly different age estimates for adults, the method was applied to skeletal collections from Postclassic Cholula and Contact-Period Xochimilco. The resulting age-at-death distributions were then compared with age-at-death distributions for the two populations constructed using traditional aging methods. Although the traditional aging methods result in age-at-death distributions with high young adult mortality and few individuals living past the age of 50, the age-at-death distributions constructed using transition analysis indicate that most individuals who lived into adulthood lived past the age of 50. Copyright © 2013 Wiley Periodicals, Inc.

Donor Age-Based Analysis of Liver Transplantation Outcomes: Short- and Long-Term Outcomes Are Similar Regardless of Donor Age.

PubMed

Chapman, William C; Vachharajani, Neeta; Collins, Kelly M; Garonzik-Wang, Jackie; Park, Yikyung; Wellen, Jason R; Lin, Yiing; Shenoy, Surendra; Lowell, Jeffrey A; Doyle, M B Majella

2015-07-01

The shortage of donor organs has led to increasing use of extended criteria donors, including older donors. The upper limit of donor age that produces acceptable outcomes continues to be explored. In liver transplantation, with appropriate selection, graft survival and patient outcomes would be comparable regardless of age. We performed a retrospective analysis of 1,036 adult orthotopic liver transplantations (OLT) from a prospectively maintained database performed between January 1, 2000 and December 31, 2013. The study focus group was liver transplantations performed using grafts from older (older than 60 years) deceased donors. Deceased donor liver transplantations done during the same time period using grafts from younger donors (younger than 60 years) were analyzed for comparison. Both groups were further divided based on recipient age (less than 60 years and 60 years or older). Donor age was the primary variable. Recipient variables included were demographics, indication for transplantation, Model for End-Stage Liver Disease (MELD), graft survival, and patient survival. Operative details and postoperative complications were analyzed. Patient demographics and perioperative details were similar between groups. Patient and graft survival rates were similar in the 4 groups. Rates of rejection (p = 0.07), bile leak (p = 0.17), and hepatic artery thrombosis were comparable across all groups (p = 0.84). Hepatitis C virus recurrence was similar across all groups (p = 0.10). Thirty-one young recipients (less than 60 years) received grafts from donors aged 70 or older. Their survival and other complication rates were comparable to those in the young donor to young recipient group. Comparable outcomes in graft and patient survivals were achieved using older donors (60 years or more), regardless of recipient age, without increased rate of complications. Copyright © 2015 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

Aging transition in systems of oscillators with global distributed-delay coupling.

PubMed

Rahman, B; Blyuss, K B; Kyrychko, Y N

2017-09-01

We consider a globally coupled network of active (oscillatory) and inactive (nonoscillatory) oscillators with distributed-delay coupling. Conditions for aging transition, associated with suppression of oscillations, are derived for uniform and gamma delay distributions in terms of coupling parameters and the proportion of inactive oscillators. The results suggest that for the uniform distribution increasing the width of distribution for the same mean delay allows aging transition to happen for a smaller coupling strength and a smaller proportion of inactive elements. For gamma distribution with sufficiently large mean time delay, it may be possible to achieve aging transition for an arbitrary proportion of inactive oscillators, as long as the coupling strength lies in a certain range.

Mapping spatial distribution of forest age in China

NASA Astrophysics Data System (ADS)

Zhang, Yuan; Yao, Yitong; Wang, Xuhui; Liu, Yongwen; Piao, Shilong

2017-03-01

Forest stand age is a meaningful metric, which reflects the past disturbance legacy, provides guidelines for forest management practices, and is an important factor in qualifying forest carbon cycles and carbon sequestration potential. Reliable large-scale forest stand age information with high spatial resolutions, however, is difficult to obtain. In this study, we developed a top-down method to downscale the provincial statistics of national forest inventory data into 1 km stand age map using climate data and light detection and ranging-derived forest height. We find that the distribution of forest stand age in China is highly heterogeneous across the country, with a mean value of 42.6 years old. The relatively young stand age for Chinese forests is mostly due to the large proportion of newly planted forests (0-40 years old), which are more prevailing in south China. Older forests (stand age > 60 years old) are more frequently found in east Qinghai-Tibetan Plateau and the central mountain areas of west and northeast China, where human activities are less intensive. Among the 15 forest types, forests dominated by species of Taxodiaceae, with the exception of Cunninghamia lanceolata stands, have the oldest mean stand age (136 years), whereas Pinus massoniana forests are the youngest (18 years). We further identified uncertainties associated with our forest age map, which are high in west and northeast China. Our work documents the distribution of forest stand age in China at a high resolution which is useful for carbon cycle modeling and the sustainable use of China's forest resources.

Quantitative distribution of GABA-immunoreactive neurons in cetacean visual cortex is similar to that in land mammals.

PubMed

Garey, L J; Takács, J; Revishchin, A V; Hámori, J

1989-04-24

Sections of the anterior portion of the visual cortex in the lateral gyrus of the Black Sea porpoise were studied to determine the neuronal architecture and numerical density, and the distribution of neurons immunoreactive to gamma-aminobutyric acid (GABA). Cytoarchitecture and neuronal density are similar to those described in another cetacean, the bottlenose dolphin. GABA-positive neurons are distributed through all layers of the visual cortex but are especially dense in layers II and III, and comprise some 20% of the total neuronal population in this part of the cortex. The distribution of GABA-positive neurons is similar to that found in land mammals.

Age-Grade Distribution, 1984-85. OEA Analytic Report.

ERIC Educational Resources Information Center

New York City Board of Education, Brooklyn. Office of Educational Assessment.

The 1984-85 age-grade distribution for the New York City Public Schools shows that one-third of the city's approximately 850,000 general education and resource room students were above the standard age for their grade. The proportion of overage students increased in the upper grades; in grades nine, ten, and eleven, over half were above standard…

An elusive paleodemography? A comparison of two methods for estimating the adult age distribution of deaths at late Classic Copan, Honduras.

PubMed

Storey, Rebecca

2007-01-01

Comparison of different adult age estimation methods on the same skeletal sample with unknown ages could forward paleodemographic inference, while researchers sort out various controversies. The original aging method for the auricular surface (Lovejoy et al., 1985a) assigned an age estimation based on several separate characteristics. Researchers have found this original method hard to apply. It is usually forgotten that before assigning an age, there was a seriation, an ordering of all available individuals from youngest to oldest. Thus, age estimation reflected the place of an individual within its sample. A recent article (Buckberry and Chamberlain, 2002) proposed a revised method that scores theses various characteristics into age stages, which can then be used with a Bayesian method to estimate an adult age distribution for the sample. Both methods were applied to the adult auricular surfaces of a Pre-Columbian Maya skeletal population from Copan, Honduras and resulted in age distributions with significant numbers of older adults. However, contrary to the usual paleodemographic distribution, one Bayesian estimation based on uniform prior probabilities yielded a population with 57% of the ages at death over 65, while another based on a high mortality life table still had 12% of the individuals aged over 75 years. The seriation method yielded an age distribution more similar to that known from preindustrial historical situations, without excessive longevity of adults. Paleodemography must still wrestle with its elusive goal of accurate adult age estimation from skeletons, a necessary base for demographic study of past populations. (c) 2006 Wiley-Liss, Inc

Transit-time and age distributions for nonlinear time-dependent compartmental systems.

PubMed

Metzler, Holger; Müller, Markus; Sierra, Carlos A

2018-02-06

Many processes in nature are modeled using compartmental systems (reservoir/pool/box systems). Usually, they are expressed as a set of first-order differential equations describing the transfer of matter across a network of compartments. The concepts of age of matter in compartments and the time required for particles to transit the system are important diagnostics of these models with applications to a wide range of scientific questions. Until now, explicit formulas for transit-time and age distributions of nonlinear time-dependent compartmental systems were not available. We compute densities for these types of systems under the assumption of well-mixed compartments. Assuming that a solution of the nonlinear system is available at least numerically, we show how to construct a linear time-dependent system with the same solution trajectory. We demonstrate how to exploit this solution to compute transit-time and age distributions in dependence on given start values and initial age distributions. Furthermore, we derive equations for the time evolution of quantiles and moments of the age distributions. Our results generalize available density formulas for the linear time-independent case and mean-age formulas for the linear time-dependent case. As an example, we apply our formulas to a nonlinear and a linear version of a simple global carbon cycle model driven by a time-dependent input signal which represents fossil fuel additions. We derive time-dependent age distributions for all compartments and calculate the time it takes to remove fossil carbon in a business-as-usual scenario.

Statistical self-similarity of hotspot seamount volumes modeled as self-similar criticality

USGS Publications Warehouse

Tebbens, S.F.; Burroughs, S.M.; Barton, C.C.; Naar, D.F.

2001-01-01

The processes responsible for hotspot seamount formation are complex, yet the cumulative frequency-volume distribution of hotspot seamounts in the Easter Island/Salas y Gomez Chain (ESC) is found to be well-described by an upper-truncated power law. We develop a model for hotspot seamount formation where uniform energy input produces events initiated on a self-similar distribution of critical cells. We call this model Self-Similar Criticality (SSC). By allowing the spatial distribution of magma migration to be self-similar, the SSC model recreates the observed ESC seamount volume distribution. The SSC model may have broad applicability to other natural systems.

Age-related increases in false recognition: the role of perceptual and conceptual similarity.

PubMed

Pidgeon, Laura M; Morcom, Alexa M

2014-01-01

Older adults (OAs) are more likely to falsely recognize novel events than young adults, and recent behavioral and neuroimaging evidence points to a reduced ability to distinguish overlapping information due to decline in hippocampal pattern separation. However, other data suggest a critical role for semantic similarity. Koutstaal et al. [(2003) false recognition of abstract vs. common objects in older and younger adults: testing the semantic categorization account, J. Exp. Psychol. Learn. 29, 499-510] reported that OAs were only vulnerable to false recognition of items with pre-existing semantic representations. We replicated Koutstaal et al.'s (2003) second experiment and examined the influence of independently rated perceptual and conceptual similarity between stimuli and lures. At study, young and OAs judged the pleasantness of pictures of abstract (unfamiliar) and concrete (familiar) items, followed by a surprise recognition test including studied items, similar lures, and novel unrelated items. Experiment 1 used dichotomous "old/new" responses at test, while in Experiment 2 participants were also asked to judge lures as "similar," to increase explicit demands on pattern separation. In both experiments, OAs showed a greater increase in false recognition for concrete than abstract items relative to the young, replicating Koutstaal et al.'s (2003) findings. However, unlike in the earlier study, there was also an age-related increase in false recognition of abstract lures when multiple similar images had been studied. In line with pattern separation accounts of false recognition, OAs were more likely to misclassify concrete lures with high and moderate, but not low degrees of rated similarity to studied items. Results are consistent with the view that OAs are particularly susceptible to semantic interference in recognition memory, and with the possibility that this reflects age-related decline in pattern separation.

Age-related increases in false recognition: the role of perceptual and conceptual similarity

PubMed Central

Pidgeon, Laura M.; Morcom, Alexa M.

2014-01-01

Older adults (OAs) are more likely to falsely recognize novel events than young adults, and recent behavioral and neuroimaging evidence points to a reduced ability to distinguish overlapping information due to decline in hippocampal pattern separation. However, other data suggest a critical role for semantic similarity. Koutstaal et al. [(2003) false recognition of abstract vs. common objects in older and younger adults: testing the semantic categorization account, J. Exp. Psychol. Learn. 29, 499–510] reported that OAs were only vulnerable to false recognition of items with pre-existing semantic representations. We replicated Koutstaal et al.’s (2003) second experiment and examined the influence of independently rated perceptual and conceptual similarity between stimuli and lures. At study, young and OAs judged the pleasantness of pictures of abstract (unfamiliar) and concrete (familiar) items, followed by a surprise recognition test including studied items, similar lures, and novel unrelated items. Experiment 1 used dichotomous “old/new” responses at test, while in Experiment 2 participants were also asked to judge lures as “similar,” to increase explicit demands on pattern separation. In both experiments, OAs showed a greater increase in false recognition for concrete than abstract items relative to the young, replicating Koutstaal et al.’s (2003) findings. However, unlike in the earlier study, there was also an age-related increase in false recognition of abstract lures when multiple similar images had been studied. In line with pattern separation accounts of false recognition, OAs were more likely to misclassify concrete lures with high and moderate, but not low degrees of rated similarity to studied items. Results are consistent with the view that OAs are particularly susceptible to semantic interference in recognition memory, and with the possibility that this reflects age-related decline in pattern separation. PMID:25368576

The changing age distribution of prostate cancer in Canada.

PubMed

Neutel, C Ineke; Gao, Ru-Nie; Blood, Paul A; Gaudette, Leslie A

2007-01-01

Prostate cancer incidence rates are still increasing steadily; mortality rates are levelling, possibly decreasing; and hospitalization rates for many diagnoses are decreasing. Our objective is to examine changes in age distributions of prostate cancer during these times of change. Prostate cancer cases were derived from the Canadian Cancer Registry, prostate cancer deaths from Vital Statistics, hospitalizations from the Hospital Morbidity File. Age-standardized rates were calculated based on the 1991 Canadian population. A prevalence correction for incidence rates was calculated. Age-specific incidence rates increased until 1995 for all ages, but a superimposed peak (1991-94) was greatest between ages 60-79. After 1995, increases in incidence continued for the under-70 age groups. Prevalence correction indicated the greatest underestimation of incidence rates for the oldest ages, but was less in Canada than in the United States. Mortality rates increased until 1994, then levelled and slowly decreased; age-specific mortality rates showed the greatest increase for the oldest ages but the earliest downturn for younger age groups. While hospitalizations dropped drastically after 1991, this drop was confined to elderly men (70+). Dramatic changes in age distributions of prostate cancer incidence, mortality and hospitalizations altered age profiles of men with prostate cancer. This illustrated the changing nature of prostate cancer as a public health issue and has important implications for health care provision, e.g., the increased numbers of younger new patients have different needs from the increasing numbers of elderly long-term patients who now spend less time in hospital.

Distributed Similarity based Clustering and Compressed Forwarding for wireless sensor networks.

PubMed

Arunraja, Muruganantham; Malathi, Veluchamy; Sakthivel, Erulappan

2015-11-01

Wireless sensor networks are engaged in various data gathering applications. The major bottleneck in wireless data gathering systems is the finite energy of sensor nodes. By conserving the on board energy, the life span of wireless sensor network can be well extended. Data communication being the dominant energy consuming activity of wireless sensor network, data reduction can serve better in conserving the nodal energy. Spatial and temporal correlation among the sensor data is exploited to reduce the data communications. Data similar cluster formation is an effective way to exploit spatial correlation among the neighboring sensors. By sending only a subset of data and estimate the rest using this subset is the contemporary way of exploiting temporal correlation. In Distributed Similarity based Clustering and Compressed Forwarding for wireless sensor networks, we construct data similar iso-clusters with minimal communication overhead. The intra-cluster communication is reduced using adaptive-normalized least mean squares based dual prediction framework. The cluster head reduces the inter-cluster data payload using a lossless compressive forwarding technique. The proposed work achieves significant data reduction in both the intra-cluster and the inter-cluster communications, with the optimal data accuracy of collected data. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Paleoclimate Signals and Age Distributions from 41 Public Water Works in the Netherlands

NASA Astrophysics Data System (ADS)

Broers, H. P.; Weert, J. D.; Sültenfuß, J.; Aeschbach, W.; Vonhof, H.; Casteleijns, J.

2015-12-01

Knowing the age distribution of water abstracted from public water supply wells is of prime importance to ensure customer trust and to underpin predictions of water quality evolution in time. Especially, age distributions enable the assessment of the vulnerability of well fields, both in relation to surface sources of contamination as in relation to subsurface sources, such as possibly related to shale gas extraction. We sampled the raw water of 41 large public supply well fields which represents a mixture of groundwaters and used the a discrete travel time distribution model (DTTDM, Visser et al. 2013, WRR) in order to quantify the age distribution of the mixture. Measurements included major ion chemistry, 3H, 3He, 4He, 18O, 2H, 14C, 13CDIC and 13CCH4 and the full range of noble gases. The heavier noble gases enable the calculation of the Noble Gas Temperature (NGT) which characterizes the temperature of past recharge conditions. The 14C apparent age of each mixture was derived correcting for dead carbon sources. The DTTDM used the 3H and 4He concentrations, the 14C apparent age and the NGT as the four distinctive tracers to estimate the age distributions. Especially 4He and NGT provide extra information on the older part of the age distributions and showed that the 14C apparent ages are often the result of mixing of waters ranging between 2.000 and 35.000 years old, instead of being discrete ages with a limited .variance as sometimes assumed.The results show a large range of age distributions, comprising vulnerable well fields with >60% young water (< 100 yrs) and well-protected well fields with >85% very old groundwater (> 25 kyrs) and all forms of TTD's in between. The age distributions are well in correspondence with the hydrogeological setting of the well fields; all well fields with an age distribution skewed towards older ages are in the Roer Valley Graben structure, where fluvial and marine aquitards provide protection from recent recharge. Especially

Paleoclimate signals and age distributions from 41 public water works in the Netherlands

NASA Astrophysics Data System (ADS)

Broers, Hans Peter; de Weert, Jasperien; Sueltenfuss, Juergen; Aeschbach-Hertig, Werner; Vonhof, Hubert; Casteleijns, Jeroen

2015-04-01

Knowing the age distribution of water abstracted from public water supply wells is of prime importance to ensure customer trust and to underpin predictions of water quality evolution in time. Especially, age distributions enable the assessment of the vulnerability of well fields, both in relation to surface sources of contamination as in relation to subsurface sources, such as possibly related to shale gas extraction. We sampled the raw water of 41 large public supply well fields which represents a mixture of groundwaters and used the a discrete travel time distribution model (DTTDM, Visser et al. 2013, WRR) in order to quantify the age distribution of the mixture. Measurements included major ion chemistry, 3H, 3He, 4He, 18O, 2H, 14C, 13CDIC and 13CCH4 and the full range of noble gases. The heavier noble gases enable the calculation of the Noble Gas Temperature (NGT) which characterizes the temperature of past recharge conditions. The 14C apparent age of each mixture was derived correcting for dead carbon sources and included carbonate dissolution and methanogenesis as the defining processes. The DTTDM used the 3H and 4He concentrations, the 14C apparent age and the NGT as the four distinctive tracers to estimate the age distributions. The use of 18O was less effective because the processes that led to more enriched values are too uncertain . Especially 4He and NGT provide extra information on the older part of the age distributions and showed that the 14C apparent ages are often the result of mixing of waters ranging between 2.000 and 35.000 years old, instead of being discrete ages with a limited .variance as sometimes assumed. The results show a large range of age distributions, comprising vulnerable well fields with >60% young water (< 100 yrs) and well-protected well fields with >85% very old groundwater (> 25 kyrs) and all forms of TTD's in between. The age distributions are well in correspondence with the hydrogeological setting of the well fields; all well

Uranium distribution and 'excessive' U-He ages in iron meteoritic troilite

NASA Technical Reports Server (NTRS)

Fisher, D. E.

1985-01-01

Fission tracking techniques were used to measure the uranium distribution in meteoritic troilite and graphite. The obtained fission tracking data showed a heterogeneous distribution of tracks with a significant portion of track density present in the form of uranium clusters at least 10 microns in size. The matrix containing the clusters was also heterogeneous in composition with U concentrations of about 0.2-4.7 ppb. U/He ages could not be estimated on the basis of the heterogeneous U distributions, so previously reported estimates of U/He ages in the presolar range are probably invalid.

The Origin of the Milky Way's Halo Age Distribution

NASA Astrophysics Data System (ADS)

Carollo, Daniela; Tissera, Patricia B.; Beers, Timothy C.; Gudin, Dmitrii; Gibson, Brad K.; Freeman, Ken C.; Monachesi, Antonela

2018-05-01

We present an analysis of the radial age gradients for the stellar halos of five Milky Way (MW) mass-sized systems simulated as part of the Aquarius Project. The halos show a diversity of age trends, reflecting their different assembly histories. Four of the simulated halos possess clear negative age gradients, ranging from approximately ‑7 to ‑19 Myr kpc‑1, shallower than those determined by recent observational studies of the Milky Way’s stellar halo. However, when restricting the analysis to the accreted component alone, all of the stellar halos exhibit a steeper negative age gradient with values ranging from ‑8 to ‑32 Myr kpc‑1, closer to those observed in the Galaxy. Two of the accretion-dominated simulated halos show a large concentration of old stars in the center, in agreement with the Ancient Chronographic Sphere reported observationally. The stellar halo that best reproduces the current observed characteristics of the age distributions of the Galaxy is that formed principally by the accretion of small satellite galaxies. Our findings suggest that the hierarchical clustering scenario can reproduce the MW’s halo age distribution if the stellar halo was assembled from accretion and the disruption of satellite galaxies with dynamical masses less than ∼109.5 M ⊙, and a minimal in situ contribution.

Greater Perceived Similarity between Self and Own-Age Others in Older than Young Adults

PubMed Central

Lin, Tian; Ankudowich, Elizabeth; Ebner, Natalie C.

2017-01-01

As people age, they increasingly incorporate age-stereotypes into their self-view. Based on this evidence we propose that older compared to young adults identify to a greater extent with their own-age group on personality traits, an effect that may be particularly pronounced for positive traits. Two studies tested these hypotheses by examining associations in young and older adults between evaluations of self and own-age others on personality traits that varied on valence. In both studies, young and older participants rated personality trait adjectives on age typicality, valence, and self typicality. Converging results across both studies showed that older compared to young participants were more likely to endorse personality traits as self-typical when those traits were also perceived as more typical for their own-age group, independent of whether age was made salient to participants prior to evaluation. In addition, there was evidence that the association between evaluations of self and own-age others in older participants was greater for more positive personality traits. This age-differential pattern is discussed in the context of increased age salience in aging and its effect on the similarity between evaluations of self and own-age others in older compared to young adults. PMID:28471216

Solving the transient water age distribution problem in environmental flow systems

NASA Astrophysics Data System (ADS)

Cornaton, F. J.

2011-12-01

The temporal evolution of groundwater age and its frequency distributions can display important changes as flow regimes vary due to the natural change in climate and hydrologic conditions and/or to human induced pressures on the resource to satisfy the water demand. Groundwater age being nowadays frequently used to investigate reservoir properties and recharge conditions, special attention needs to be put on the way this property is characterized, would it be using isotopic methods, multiple tracer techniques, or mathematical modelling. Steady-state age frequency distributions can be modelled using standard numerical techniques, since the general balance equation describing age transport under steady-state flow conditions is exactly equivalent to a standard advection-dispersion equation. The time-dependent problem is however described by an extended transport operator that incorporates an additional coordinate for water age. The consequence is that numerical solutions can hardly be achieved, especially for real 3-D applications over large time periods of interest. The absence of any robust method has thus left us in the quantitative hydrogeology community dodging the issue of transience. Novel algorithms for solving the age distribution problem under time-varying flow regimes are presented and, for some specific configurations, extended to the problem of generalized component exposure time. The solution strategy is based on the combination of the Laplace Transform technique applied to the age (or exposure time) coordinate with standard time-marching schemes. The method is well-suited for groundwater problems with possible density-dependency of fluid flow (e.g. coupled flow and heat/salt concentration problems), but also presents significance to the homogeneous flow (compressible case) problem. The approach is validated using 1-D analytical solutions and exercised on some demonstration problems that are relevant to topical issues in groundwater age, including

Paying attention to working memory: Similarities in the spatial distribution of attention in mental and physical space.

PubMed

Sahan, Muhammet Ikbal; Verguts, Tom; Boehler, Carsten Nicolas; Pourtois, Gilles; Fias, Wim

2016-08-01

Selective attention is not limited to information that is physically present in the external world, but can also operate on mental representations in the internal world. However, it is not known whether the mechanisms of attentional selection operate in similar fashions in physical and mental space. We studied the spatial distributions of attention for items in physical and mental space by comparing how successfully distractors were rejected at varying distances from the attended location. The results indicated very similar distribution characteristics of spatial attention in physical and mental space. Specifically, we found that performance monotonically improved with increasing distractor distance relative to the attended location, suggesting that distractor confusability is particularly pronounced for nearby distractors, relative to distractors farther away. The present findings suggest that mental representations preserve their spatial configuration in working memory, and that similar mechanistic principles underlie selective attention in physical and in mental space.

Variable step random walks, self-similar distributions, and pricing of options (Invited Paper)

NASA Astrophysics Data System (ADS)

Gunaratne, Gemunu H.; McCauley, Joseph L.

2005-05-01

A new theory for pricing of options is presented. It is based on the assumption that successive movements depend on the value of the return. The solution to the Fokker-Planck equation is shown to be an asymmetric exponential distribution, similar to those observed in intra-day currency markets. The "volatility smile", used by traders to correct the Black-Scholes pricing is shown to be a heuristic mechanism to implement options pricing formulae derived from our theory.

[Using the sequenced sample cluster analysis to study the body mass index distribution characteristics of adults in different age groups and genders].

PubMed

Cai, Y N; Pei, X T; Sun, P P; Xu, Y P; Liu, L; Ping, Z G

2018-06-10

Objective: To explore the characteristics of distribution on Chinese adult body mass index (BMI) in different age groups and genders and to provide reference related to obesity and related chronic diseases. Methods: Data from the China Health and Nutrition Survey in 2009 were used. Sequential sample cluster method was used to analyze the characteristics of BMI distribution in different age groups and genders by SAS. Results: Our results showed that the adult BMI in China should be divided into 3 groups according to their age, as 20 to 40 years old, 40 to 65 years old, and> 65 years old, in females or in total when grouped by difference of 5 years. For groupings in male, the three groups should be as 20 to 40, 40 to 60 years old and>60 years old. There were differences on distribution between the male and female groups. When grouped by difference of 10 years, all of the clusters for male, female and total groups as 20-40, 40-60 and>60 years old, became similar for the three classes, respectively, with no differences of distribution between gender, suggesting that the 5-years grouping was more accurate than the 10-years one, and BMI showing gender differences. Conclusions: BMI of the Chinese adults should be divided into 3 categories according to the characteristics of their age. Our results showed that BMI was increasing with age in youths and adolescents, remained unchanged in the middle-aged but decreasing in the elderly.

Summer distributions of forage fish in the eastern Bering Sea

NASA Astrophysics Data System (ADS)

Parker-Stetter, Sandra L.; Horne, John K.; Farley, Edward V.; Barbee, David H.; Andrews, Alexander G.; Eisner, Lisa B.; Nomura, Jennifer M.

2013-10-01

Juvenile and small adult fish, typically called forage fish, are an important but poorly studied part of the eastern Bering Sea (EBS) ecosystem. Acoustic and trawl data from a non-target survey were used to evaluate distributions of capelin (Mallotus villosus), age-0 Pacific cod (Gadus macrocephalus), and age-0 walleye pollock (Theragra chalcogramma, herein pollock) in 2006-2010. Within the surface zone (15 m to ~35 m, evaluated 2006-2010), capelin occurred throughout the EBS but primarily in the middle shelf. Capelin were also present in the midwater zone (~35 m to 0.5 m off-bottom) in both 2009 and 2010 (evaluated 2009-2010), and resulted in water column zone (15 m to 0.5 m off-bottom) distributions that differed from surface zone characterizations. Age-0 Pacific cod occurred primarily in the surface zone of the middle and outer shelf regions in all years. As midwater and surface zone age-0 Pacific cod were often coincident, water column zone distributions in 2009-2010 were similar to surface zone distributions. Age-0 pollock were found in the EBS surface zone in all years, primarily in the middle and outer shelf regions. High densities of age-0 pollock occurred in the midwater zone in 2006-2007 and 2009-2010. Water column zone distributions of age-0 pollock were similar to surface zone distributions in 2006-2007, but differed in 2009-2010 due to low numbers of age-0 pollock in the surface zone and presence of high densities in the midwater zone of the outer shelf region. While general patterns in capelin distribution in the surface zone were similar between the present and the previous studies, the acoustic-trawl characterization suggested that capelin densities were high in the middle shelf region. As expected, surface zone distributions of age-0 Pacific cod and age-0 pollock were similar to previous characterizations. Observed high densities of midwater age-0 pollock have not been described by previous studies. Annual abundance indices based on bottom or

Age distribution of lithium-cesium-tantalum enriched pegmatites and relationships to orogeny

NASA Astrophysics Data System (ADS)

McCauley, A.; Bradley, D. C.

2011-12-01

Pegmatites account for about one third of the world's lithium production, most of the tantalum, and all of the cesium. Pegmatites enriched in these elements (LCT pegmatites) are widely interpreted as extreme fractionation products of orogenic granitic melts, although it is not always possible to tie a particular pegmatite to a known granite of the same age. The global age distribution of LCT pegmatites is similar to the age distributions of common pegmatites, of orogenic granites, and of detrital zircons. Our geochronological synthesis expands on, and generally confirms, the recent study by Tkachev (2011, Geol. Soc. Spec. Publ. 350, 7). The LCT pegmatite maxima at ca. 2650, 1800, 525, 350, and 100 Ma correspond to times of collisional orogeny and, except for the comparatively minor peak at 100 Ma, to times of supercontinent assembly. Between these pulses are long intervals of few or no LCT pegmatites. Global minima in LCT pegmatite abundance overlap with supercontinent tenures at ca. 2450-2225, 1625-1000, 875-725, and 250-200 Ma, as established, for the Precambrian, from global minima in the abundances of passive margins and detrital zircons. A key question that bears on both metallogenesis and exploration strategies is why are some orogenic belts well endowed with LCT pegmatites, whereas other, seemingly similar orogens are barren? For the present study, LCT pegmatites from the Appalachian, Variscan, Damara, and Argentine Precordilleran orogens are being dated by the U-Pb method to relate pegmatite emplacement to other igneous events, shortening, metamorphism, foreland-basin sedimentation, and, on the broadest scale, to supercontinent assembly. Anecdotal evidence suggests that LCT pegmatites typically are emplaced late in orogenic cycles. In the Inland Branch of the Damaride orogen, about 45 m.y. elapsed between initial arc-passive margin collision at ca. 550 Ma and LCT pegmatite emplacement at ca. 505 Ma, very late in the assembly of this part of Gondwana. In the

Target-distractor similarity has a larger impact on visual search in school-age children than spacing.

PubMed

Huurneman, Bianca; Boonstra, F Nienke

2015-01-22

In typically developing children, crowding decreases with increasing age. The influence of target-distractor similarity with respect to orientation and element spacing on visual search performance was investigated in 29 school-age children with normal vision (4- to 6-year-olds [N = 16], 7- to 8-year-olds [N = 13]). Children were instructed to search for a target E among distractor Es (feature search: all flanking Es pointing right; conjunction search: flankers in three orientations). Orientation of the target was manipulated in four directions: right (target absent), left (inversed), up, and down (vertical). Spacing was varied in four steps: 0.04°, 0.5°, 1°, and 2°. During feature search, high target-distractor similarity had a stronger impact on performance than spacing: Orientation affected accuracy until spacing was 1°, and spacing only influenced accuracy for identifying inversed targets. Spatial analyses showed that orientation affected oculomotor strategy: Children made more fixations in the "inversed" target area (4.6) than the vertical target areas (1.8 and 1.9). Furthermore, age groups differed in fixation duration: 4- to 6-year-old children showed longer fixation durations than 7- to 8-year-olds at the two largest element spacings (p = 0.039 and p = 0.027). Conjunction search performance was unaffected by spacing. Four conclusions can be drawn from this study: (a) Target-distractor similarity governs visual search performance in school-age children, (b) children make more fixations in target areas when target-distractor similarity is high, (c) 4- to 6-year-olds show longer fixation durations than 7- to 8-year-olds at 1° and 2° element spacing, and (d) spacing affects feature but not conjunction search-a finding that might indicate top-down control ameliorates crowding in children. © 2015 ARVO.

Similar verbal memory impairments in schizophrenia and healthy aging. Implications for understanding of neural mechanisms.

PubMed

Silver, Henry; Bilker, Warren B

2015-03-30

Memory is impaired in schizophrenia patients but it is not clear whether this is specific to the illness and whether different types of memory (verbal and nonverbal) or memories in different cognitive domains (executive, object recognition) are similarly affected. To study relationships between memory impairments and schizophrenia we compared memory functions in 77 schizophrenia patients, 58 elderly healthy individuals and 41 young healthy individuals. Tests included verbal associative and logical memory and memory in executive and object recognition domains. We compared relationships of memory functions to each other and to other cognitive functions including psychomotor speed and verbal and spatial working memory. Compared to the young healthy group, schizophrenia patients and elderly healthy individuals showed similar severe impairment in logical memory and in the ability to learn new associations (NAL), and similar but less severe impairment in spatial working memory and executive and object memory. Verbal working memory was significantly more impaired in schizophrenia patients than in the healthy elderly. Verbal episodic memory impairment in schizophrenia may share common mechanisms with similar impairment in healthy aging. Impairment in verbal working memory in contrast may reflect mechanisms specific to schizophrenia. Study of verbal explicit memory impairment tapped by the NAL index may advance understanding of abnormal hippocampus dependent mechanisms common to schizophrenia and aging. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Streamline similarity method for flow distributions and shock losses at the impeller inlet of the centrifugal pump

NASA Astrophysics Data System (ADS)

Zhang, Zh.

2018-02-01

An analytical method is presented, which enables the non-uniform velocity and pressure distributions at the impeller inlet of a pump to be accurately computed. The analyses are based on the potential flow theory and the geometrical similarity of the streamline distribution along the leading edge of the impeller blades. The method is thus called streamline similarity method (SSM). The obtained geometrical form of the flow distribution is then simply described by the geometrical variable G( s) and the first structural constant G I . As clearly demonstrated and also validated by experiments, both the flow velocity and the pressure distributions at the impeller inlet are usually highly non-uniform. This knowledge is indispensible for impeller blade designs to fulfill the shockless inlet flow condition. By introducing the second structural constant G II , the paper also presents the simple and accurate computation of the shock loss, which occurs at the impeller inlet. The introduction of two structural constants contributes immensely to the enhancement of the computational accuracies. As further indicated, all computations presented in this paper can also be well applied to the non-uniform exit flow out of an impeller of the Francis turbine for accurately computing the related mean values.

Distributional learning aids linguistic category formation in school-age children.

PubMed

Hall, Jessica; Owen VAN Horne, Amanda; Farmer, Thomas

2018-05-01

The goal of this study was to determine if typically developing children could form grammatical categories from distributional information alone. Twenty-seven children aged six to nine listened to an artificial grammar which contained strategic gaps in its distribution. At test, we compared how children rated novel sentences that fit the grammar to sentences that were ungrammatical. Sentences could be distinguished only through the formation of categories of words with shared distributional properties. Children's ratings revealed that they could discriminate grammatical and ungrammatical sentences. These data lend support to the hypothesis that distributional learning is a potential mechanism for learning grammatical categories in a first language.

The distribution of lobate debris aprons and similar flows on Mars

NASA Technical Reports Server (NTRS)

Squyres, S. W.

1979-01-01

Planet-wide mapping of lobate debris aprons and other similar flows on Mars shows a strong concentration in two latitudinal bands roughly 25 deg wide and centered at 40 deg N and 45 deg S. This distribution supports the idea that these flows form when erosional debris is transported downslope and becomes mixed with ice deposited from the atmosphere, as these latitudes should receive high seasonal H2O frost deposition relative to the rest of the planet. Flows are found in the northern hemisphere band wherever old highland surfaces occur but are found in the southern hemisphere only near the two major impact basins, Argyre and Hellas. These areas are apparently characterized by mass wasting that is rapid relative to most of the southern hemisphere highlands. The rate of mass wasting may be related to the degree of consolidation of highland material.

A Bayesian Modeling Approach for Estimation of a Shape-Free Groundwater Age Distribution using Multiple Tracers

DOE PAGES

Massoudieh, Arash; Visser, Ate; Sharifi, Soroosh; ...

2013-10-15

The mixing of groundwaters with different ages in aquifers, groundwater age is more appropriately represented by a distribution rather than a scalar number. To infer a groundwater age distribution from environmental tracers, a mathematical form is often assumed for the shape of the distribution and the parameters of the mathematical distribution are estimated using deterministic or stochastic inverse methods. We found that the prescription of the mathematical form limits the exploration of the age distribution to the shapes that can be described by the selected distribution. In this paper, the use of freeform histograms as groundwater age distributions is evaluated.more » A Bayesian Markov Chain Monte Carlo approach is used to estimate the fraction of groundwater in each histogram bin. This method was able to capture the shape of a hypothetical gamma distribution from the concentrations of four age tracers. The number of bins that can be considered in this approach is limited based on the number of tracers available. The histogram method was also tested on tracer data sets from Holten (The Netherlands; 3H, 3He, 85Kr, 39Ar) and the La Selva Biological Station (Costa-Rica; SF 6, CFCs, 3H, 4He and 14C), and compared to a number of mathematical forms. According to standard Bayesian measures of model goodness, the best mathematical distribution performs better than the histogram distributions in terms of the ability to capture the observed tracer data relative to their complexity. Among the histogram distributions, the four bin histogram performs better in most of the cases. The Monte Carlo simulations showed strong correlations in the posterior estimates of bin contributions, indicating that these bins cannot be well constrained using the available age tracers. The fact that mathematical forms overall perform better than the freeform histogram does not undermine the benefit of the freeform approach, especially for the cases where a larger amount of observed data is

A Bayesian Modeling Approach for Estimation of a Shape-Free Groundwater Age Distribution using Multiple Tracers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Massoudieh, Arash; Visser, Ate; Sharifi, Soroosh

The mixing of groundwaters with different ages in aquifers, groundwater age is more appropriately represented by a distribution rather than a scalar number. To infer a groundwater age distribution from environmental tracers, a mathematical form is often assumed for the shape of the distribution and the parameters of the mathematical distribution are estimated using deterministic or stochastic inverse methods. We found that the prescription of the mathematical form limits the exploration of the age distribution to the shapes that can be described by the selected distribution. In this paper, the use of freeform histograms as groundwater age distributions is evaluated.more » A Bayesian Markov Chain Monte Carlo approach is used to estimate the fraction of groundwater in each histogram bin. This method was able to capture the shape of a hypothetical gamma distribution from the concentrations of four age tracers. The number of bins that can be considered in this approach is limited based on the number of tracers available. The histogram method was also tested on tracer data sets from Holten (The Netherlands; 3H, 3He, 85Kr, 39Ar) and the La Selva Biological Station (Costa-Rica; SF 6, CFCs, 3H, 4He and 14C), and compared to a number of mathematical forms. According to standard Bayesian measures of model goodness, the best mathematical distribution performs better than the histogram distributions in terms of the ability to capture the observed tracer data relative to their complexity. Among the histogram distributions, the four bin histogram performs better in most of the cases. The Monte Carlo simulations showed strong correlations in the posterior estimates of bin contributions, indicating that these bins cannot be well constrained using the available age tracers. The fact that mathematical forms overall perform better than the freeform histogram does not undermine the benefit of the freeform approach, especially for the cases where a larger amount of observed data is

Altitude Investigation of Gas Temperature Distribution at Turbine of Three Similar Axial-Flow Turbojet Engines

NASA Technical Reports Server (NTRS)

Prince, W.R.; Schulze, F.W.

1952-01-01

An investigation of the effect of inlet pressure, corrected engine speed, and turbine temperature level on turbine-inlet gas temperature distributions was conducted on a J40-WE-6, interim J40-WE-6, and prototype J40-WE-8 turbojet engine in the altitude wind tunnel at the NAC.4 Lewis laboratory. The engines were investigated over a range of simulated pressure altitudes from 15,000 to 55,000 feet, flight Mach numbers from 0.12 to 0.64, and corrected engine speeds from 7198 to 8026 rpm, The gas temperature distribution at the turbine of the three engines over the range of operating conditions investigated was considered satisfactory from the standpoint of desired temperature distribution with one exception - the distribution for the J40-WE-6 engine indicated a trend with decreasing engine-inlet pressure for the temperature to exceed the desired in the region of the blade hub. Installation of a compressor-outlet mixer vane assembly remedied this undesirable temperature distribution, The experimental data have shown that turbine-inlet temperature distributions are influenced in the expected manner by changes in compressor-outlet pressure or mass-flow distribution and by changes in combustor hole-area distribution. The similarity between turbine-inlet and turbine-outlet temperature distribution indicated only a small shift in temperature distribution imposed by the turbine rotors. The attainable jet thrusts of the three engines were influenced in different degrees and directions by changes in temperature distributions with change in engine-inlet pressure. Inability to match the desired temperature distribution resulted, for the J40-WE-6 engine, in an 11-percent thrust loss based on an average turbine-inlet temperature of 1500 F at an engine-inlet pressure of 500 pounds per square foot absolute. Departure from the desired temperature distribution in the Slade tip region results, for the prototype J40-WE-8 engine, in an attainable thrust increase of 3 to 4 percent as

Interference, aging, and visuospatial working memory: the role of similarity.

PubMed

Rowe, Gillian; Hasher, Lynn; Turcotte, Josée

2010-11-01

Older adults' performance on working memory (WM) span tasks is known to be negatively affected by the buildup of proactive interference (PI) across trials. PI has been reduced in verbal tasks and performance increased by presenting distinctive items across trials. In addition, reversing the order of trial presentation (i.e., starting with the longest sets first) has been shown to reduce PI in both verbal and visuospatial WM span tasks. We considered whether making each trial visually distinct would improve older adults' visuospatial WM performance, and whether combining the 2 PI-reducing manipulations, distinct trials and reversed order of presentation, would prove additive, thus providing even greater benefit. Forty-eight healthy older adults (age range = 60-77 years) completed 1 of 3 versions of a computerized Corsi block test. For 2 versions of the task, trials were either all visually similar or all visually distinct, and were presented in the standard ascending format (shortest set size first). In the third version, visually distinct trials were presented in a reverse order of presentation (longest set size first). Span scores were reliably higher in the ascending version for visually distinct compared with visually similar trials, F(1, 30) = 4.96, p = .03, η² = .14. However, combining distinct trials and a descending format proved no more beneficial than administering the descending format alone. Our findings suggest that a more accurate measurement of the visuospatial WM span scores of older adults (and possibly neuropsychological patients) might be obtained by reducing within-test interference.

Seasonal Distribution and Diversity of Ground Arthropods in Microhabitats Following a Shrub Plantation Age Sequence in Desertified Steppe

PubMed Central

Liu, Rentao; Zhu, Fan; Song, Naiping; Yang, Xinguo; Chai, Yongqing

2013-01-01

In desertified regions, shrub-dominated patches are important microhabitats for ground arthropod assemblages. As shrub age increases, soil, vegetation and microbiological properties can change remarkably and spontaneously across seasons. However, relatively few studies have analyzed how ground arthropods respond to the microhabitats created by shrubs of different plantation ages across seasons. Using 6, 15, 24 and 36 year-old plantations of re-vegetated shrubs (Caragana koushinskii) in the desert steppe of northwestern China as a model system, we sampled ground arthropod communities using a pitfall trapping method in the microhabitats under shrubs and in the open areas between shrubs, during the spring, summer and autumn. The total ground arthropod assemblage was dominated by Carabidae, Melolonthidae, Curculionidae, Tenebrionidae and Formicidae that were affected by plantation age, seasonal changes, or the interaction between these factors, with the later two groups also influenced by microhabitat. Overall, a facilitative effect was observed, with more arthropods and a greater diversity found under shrubs as compared to open areas, but this was markedly affected by seasonal changes. There was a high degree of similarity in arthropod assemblages and diversity between microhabitats in summer and autumn. Shrub plantation age significantly influenced the distribution of the most abundant groups, and also the diversity indices of the ground arthropods. However, there was not an overall positive relationship between shrub age and arthropod abundance, richness or diversity index. The influence of plantation age on arthropod communities was also affected by seasonal changes. From spring through summer to autumn, community indices of ground arthropods tended to decline, and a high degree of similarity in these indices (with fluctuation) was observed among different ages of shrub plantation in autumn. Altogether the recovery of arthropod communities was markedly affected by

What Can Catchment Transit Time Distributions Tell Us About Runoff Mechanisms? Exploring "Age Equifinality" with an Integrated Surface-Groundwater Model.

NASA Astrophysics Data System (ADS)

Wilusz, D. C.; Harman, C. J.; Ball, W. P.; Maxwell, R. M.; Buda, A. R.

2017-12-01

The backward transit-time distribution (bTTD) is the time-varying, probabilistic distribution of water travel times or, equivalently, water ages in catchment outflow. The bTTD is increasingly seen as a master variable of catchment hydrology that links flow and transport processes, in part because it is believed to embed information about runoff generation mechanisms (RGMs) that are difficult to directly observe. The ability to use water age to make inferences about RGMs depends on the degree of "age equifinality" in a watershed, defined here as the phenomenon where significant volumes of similarly-aged water are delivered to the outlet by different RGMs at the same time. When age equifinality is low (e.g., all discharge is old groundwater), the mapping of water age to the RGM may be simple; when age equifinality is high (e.g., discharge is a mix of old groundwater and old interflow), this mapping may be impossible. In this study we conduct experiments in a virtual watershed to (1) understand the hydrologic conditions that lead to age equifinality, (2) identify relationships between water age and RGMs that are particularly obscured/unobscured by age equifinality, and (3) test the generalizability of these relationships in other watersheds. Our experiments used the fully-distributed surface-groundwater model ParFlow, which simulates a suite of RGMs, plus SLIM-FAST particle tracking. To improve realism, the watershed model was parameterized and forced using extensive field data from the USDA's Mahantango Creek experimental catchment in PA, USA. The model output is being interrogated to understand the time-varying relationships between the composition of RGMs and the bTTD at the outlet. We are also testing the robustness of these relationships by re-running our model with controlled differences in climate, topography, and scale. Initial results suggest high age equifinality at peak flows due to overlapping young water contributions from infiltration- and saturation

[Active Substance Index (AKS) percentile distribution in pediatric ages].

PubMed

Henriquez-Pérez, Gladys; Rached-Paoli, Ingrid; Azuaje-Sánchez, Arelis

2009-12-01

The aim of this study was to discern the percentile distribution of the Active Substance Index (AKS) in boys and girls aged 4 to 9 years in order to obtain reference values for this indicator. This index was calculated in 3634 healthy and well-nourished children with normal stature from a poor urban community at Centro de Atención Nutricional Infantil Antímano (CANIA), within the period between January 1999 and December 2007. Children with prematurity backgrounds, pubertal growth spurts, or with chronic pathologies, whether defined or under study, were excluded. The Dugdale & Griffiths two-skinfold equation for boys and girls shorter than 150 cm and 140 cm, respectively was used to obtain the fat body mass required to estimate the AKS index. The variables were measured by standardized anthropometrics technicians, with quality control every 4 months as recommended by international standards. Descriptive statistics of the AKS index and variables used for their calculation were obtained, as well as index percentiles 3, 10, 25, 50, 75, 90, and 97. Tests applied included Kolmogorov-Smirnoff, Anova one-way, Chi Square, Tukey and bivariated correlations (p < 0.05). The AKS index behavior exhibited higher values in the boys, decreasing with age in both sexes, ranging from 1.28 to 1.04 in the boys and from 1.17 to 0.94 in the girls. Statistically significant differences were found for each age and sex. These results provide the AKS index percentile distribution values needed for nutritional assessments in pediatric ages. These values should be validated and their effectiveness should be studied.

Extracting information on the spatial variability in erosion rate stored in detrital cooling age distributions in river sands

NASA Astrophysics Data System (ADS)

Braun, Jean; Gemignani, Lorenzo; van der Beek, Peter

2018-03-01

One of the main purposes of detrital thermochronology is to provide constraints on the regional-scale exhumation rate and its spatial variability in actively eroding mountain ranges. Procedures that use cooling age distributions coupled with hypsometry and thermal models have been developed in order to extract quantitative estimates of erosion rate and its spatial distribution, assuming steady state between tectonic uplift and erosion. This hypothesis precludes the use of these procedures to assess the likely transient response of mountain belts to changes in tectonic or climatic forcing. Other methods are based on an a priori knowledge of the in situ distribution of ages to interpret the detrital age distributions. In this paper, we describe a simple method that, using the observed detrital mineral age distributions collected along a river, allows us to extract information about the relative distribution of erosion rates in an eroding catchment without relying on a steady-state assumption, the value of thermal parameters or an a priori knowledge of in situ age distributions. The model is based on a relatively low number of parameters describing lithological variability among the various sub-catchments and their sizes and only uses the raw ages. The method we propose is tested against synthetic age distributions to demonstrate its accuracy and the optimum conditions for it use. In order to illustrate the method, we invert age distributions collected along the main trunk of the Tsangpo-Siang-Brahmaputra river system in the eastern Himalaya. From the inversion of the cooling age distributions we predict present-day erosion rates of the catchments along the Tsangpo-Siang-Brahmaputra river system, as well as some of its tributaries. We show that detrital age distributions contain dual information about present-day erosion rate, i.e., from the predicted distribution of surface ages within each catchment and from the relative contribution of any given catchment to the

Age-related similarities in contextual cueing in the presence of unpredictive distracters.

PubMed

Yang, Yingying; Merrill, Edward C

2015-01-01

Contextual cueing effects of 6-8-year-old children, 10-12-year-old-children, and college students were compared under conditions in which some of the distracters in the search displays predicted the location of the target and other distracters did not. More specifically, the percent of distracters that predicted the location of the target varied across three conditions (100%, 67%, and 33%). Previous research had indicated that children are impacted more than adults when the percent of predictive distracters is relatively low. However, that research included new displays as well as repeated displays as participants were implicitly learning the association between the predictive distracters and the target. This re-evaluation did not introduce new display until a separate test phase. Results suggested that all three age groups demonstrated significant and comparable contextual cueing effects across all three signal-to-noise ratio conditions. Hence, children appear to possess the general ability to extract and remember information associated with spatial regularities in the presence of considerable spatial noise. In addition, contextual cueing effects were linked to improvements in search efficiency for all groups in this study, providing another degree of similarity across variations in age.

Creating Composite Age Groups to Smooth Percentile Rank Distributions of Small Samples

ERIC Educational Resources Information Center

Lopez, Francesca; Olson, Amy; Bansal, Naveen

2011-01-01

Individually administered tests are often normed on small samples, a process that may result in irregularities within and across various age or grade distributions. Test users often smooth distributions guided by Thurstone assumptions (normality and linearity) to result in norms that adhere to assumptions made about how the data should look. Test…

Asteroid age distributions determined by space weathering and collisional evolution models

NASA Astrophysics Data System (ADS)

Willman, Mark; Jedicke, Robert

2011-01-01

We provide evidence of consistency between the dynamical evolution of main belt asteroids and their color evolution due to space weathering. The dynamical age of an asteroid's surface (Bottke, W.F., Durda, D.D., Nesvorný, D., Jedicke, R., Morbidelli, A., Vokrouhlický, D., Levison, H. [2005]. Icarus 175 (1), 111-140; Nesvorný, D., Jedicke, R., Whiteley, R.J., Ivezić, Ž. [2005]. Icarus 173, 132-152) is the time since its last catastrophic disruption event which is a function of the object's diameter. The age of an S-complex asteroid's surface may also be determined from its color using a space weathering model (e.g. Willman, M., Jedicke, R., Moskovitz, N., Nesvorný, D., Vokrouhlický, D., Mothé-Diniz, T. [2010]. Icarus 208, 758-772; Jedicke, R., Nesvorný, D., Whiteley, R.J., Ivezić, Ž., Jurić, M. [2004]. Nature 429, 275-277; Willman, M., Jedicke, R., Nesvorny, D., Moskovitz, N., Ivezić, Ž., Fevig, R. [2008]. Icarus 195, 663-673. We used a sample of 95 S-complex asteroids from SMASS and obtained their absolute magnitudes and u, g, r, i, z filter magnitudes from SDSS. The absolute magnitudes yield a size-derived age distribution. The u, g, r, i, z filter magnitudes lead to the principal component color which yields a color-derived age distribution by inverting our color-age relationship, an enhanced version of the 'dual τ' space weathering model of Willman et al. (2010). We fit the size-age distribution to the enhanced dual τ model and found characteristic weathering and gardening times of τw = 2050 ± 80 Myr and τg=4400-500+700Myr respectively. The fit also suggests an initial principal component color of -0.05 ± 0.01 for fresh asteroid surface with a maximum possible change of the probable color due to weathering of Δ PC = 1.34 ± 0.04. Our predicted color of fresh asteroid surface matches the color of fresh ordinary chondritic surface of PC1 = 0.17 ± 0.39.

Changes in amount and intracellular distribution of androgen receptor in human foreskin as a function of age.

PubMed Central

Roehrborn, C G; Lange, J L; George, F W; Wilson, J D

1987-01-01

To provide insight into the factors that control growth of the penis we measured the amount and intracellular distribution of specific high affinity androgen receptor in foreskins obtained at circumcision from 49 males varying in age from newborn to 59 yr. Total (cytosolic plus nuclear extract) androgen receptor decreased from approximately 40 fmol/g tissue weight in newborn foreskins to approximately 25 fmol/g by 1 yr of age. The amount of receptor rose in childhood to approximately 180 fmol/g in the late teenage years and fell thereafter to approximately 20-40 fmol/g in men older than 40 yr. The amount of receptor in the nuclear fraction increased at the time of puberty and subsequently decreased in parallel with the decline in total receptor level. These changes in androgen-receptor amount are similar when expressed per milligram DNA or per milligram protein. Images PMID:3491838

Global survey of star clusters in the Milky Way. VI. Age distribution and cluster formation history

NASA Astrophysics Data System (ADS)

Piskunov, A. E.; Just, A.; Kharchenko, N. V.; Berczik, P.; Scholz, R.-D.; Reffert, S.; Yen, S. X.

2018-06-01

Context. The all-sky Milky Way Star Clusters (MWSC) survey provides uniform and precise ages, along with other relevant parameters, for a wide variety of clusters in the extended solar neighbourhood. Aims: In this study we aim to construct the cluster age distribution, investigate its spatial variations, and discuss constraints on cluster formation scenarios of the Galactic disk during the last 5 Gyrs. Methods: Due to the spatial extent of the MWSC, we have considered spatial variations of the age distribution along galactocentric radius RG, and along Z-axis. For the analysis of the age distribution we used 2242 clusters, which all lie within roughly 2.5 kpc of the Sun. To connect the observed age distribution to the cluster formation history we built an analytical model based on simple assumptions on the cluster initial mass function and on the cluster mass-lifetime relation, fit it to the observations, and determined the parameters of the cluster formation law. Results: Comparison with the literature shows that earlier results strongly underestimated the number of evolved clusters with ages t ≳ 100 Myr. Recent studies based on all-sky catalogues agree better with our data, but still lack the oldest clusters with ages t ≳ 1 Gyr. We do not observe a strong variation in the age distribution along RG, though we find an enhanced fraction of older clusters (t > 1 Gyr) in the inner disk. In contrast, the distribution strongly varies along Z. The high altitude distribution practically does not contain clusters with t < 1 Gyr. With simple assumptions on the cluster formation history, the cluster initial mass function and the cluster lifetime we can reproduce the observations. The cluster formation rate and the cluster lifetime are strongly degenerate, which does not allow us to disentangle different formation scenarios. In all cases the cluster formation rate is strongly declining with time, and the cluster initial mass function is very shallow at the high mass end.

Test of Monin-Obukhov similarity theory using distributed temperature sensing

NASA Astrophysics Data System (ADS)

Cheng, Y.; Sayde, C.; Li, Q.; Gentine, P.

2017-12-01

Monin-Obukhov similarity theory [Monin and Obukhov, 1954] (MOST) has been widely used to calculate atmospheric surface fluxes applying the structure correction functions [Stull, 1988]. The exact forms of the structure correction functions for momentum and heat, which depend on the vertical gradient velocity and temperature, have been determined empirically mostly from the Kansas experiment [Kaimal et al., 1972]. However, due to the limitation of point measurement, the vertical gradient of temperature and horizontal wind speed are not well captured. Here we propose a way to measure the vertical gradient of temperature and horizontal wind speed with high resolution in space (every 12.7 cm) and time (every second) using the Distributed Temperature Sensing [Selker et al., 2006] (DTS), thus determining the exact form of the structure correction functions of MOST under various stability conditions. Two parallel vertical fiber optics will be placed on a tower at the central facility of ARM SGP site. Vertical air temperature will be measured every 12.7 cm by the fiber optics and horizontal wind speed along fiber will be measured. Then vertical gradient of temperature and horizontal wind speed will be calculated and stability correction functions for momentum and heat will be determined. ReferencesKaimal, J. C., Wyngaard, J. C., Izumi, Y., and Cote, O. R. (1972), Spectral characteristics of surface-layer turbulence, Quarterly Journal of the Royal Meteorological Society, 98(417), 563-589, doi: 10.1002/qj.49709841707. Monin, A., and Obukhov, A. (1954), Basic laws of turbulent mixing in the surface layer of the atmosphere, Contrib. Geophys. Inst. Acad. Sci. USSR, 24(151), 163-187. Selker, J., Thévenaz, L., Huwald, H., Mallet, A., Luxemburg, W., van de Giesen, N., Stejskal, M., Zeman, J., Westhoff, M., and Parlange, M. B. (2006), Distributed fiber-optic temperature sensing for hydrologic systems, Water Resources Research, 42, W12202, doi: 10.1029/2006wr005326. Stull, R. (1988

Modeling the brain morphology distribution in the general aging population

NASA Astrophysics Data System (ADS)

Huizinga, W.; Poot, D. H. J.; Roshchupkin, G.; Bron, E. E.; Ikram, M. A.; Vernooij, M. W.; Rueckert, D.; Niessen, W. J.; Klein, S.

2016-03-01

Both normal aging and neurodegenerative diseases such as Alzheimer's disease cause morphological changes of the brain. To better distinguish between normal and abnormal cases, it is necessary to model changes in brain morphology owing to normal aging. To this end, we developed a method for analyzing and visualizing these changes for the entire brain morphology distribution in the general aging population. The method is applied to 1000 subjects from a large population imaging study in the elderly, from which 900 were used to train the model and 100 were used for testing. The results of the 100 test subjects show that the model generalizes to subjects outside the model population. Smooth percentile curves showing the brain morphology changes as a function of age and spatiotemporal atlases derived from the model population are publicly available via an interactive web application at agingbrain.bigr.nl.

The mouse age phenome knowledgebase and disease-specific inter-species age mapping.

PubMed

Geifman, Nophar; Rubin, Eitan

2013-01-01

Similarities between mice and humans lead to generation of many mouse models of human disease. However, differences between the species often result in mice being unreliable as preclinical models for human disease. One difference that might play a role in lowering the predictivity of mice models to human diseases is age. Despite the important role age plays in medicine, it is too often considered only casually when considering mouse models. We developed the mouse-Age Phenotype Knowledgebase, which holds knowledge about age-related phenotypic patterns in mice. The knowledgebase was extensively populated with literature-derived data using text mining techniques. We then mapped between ages in humans and mice by comparing the age distribution pattern for 887 diseases in both species. The knowledgebase was populated with over 9800 instances generated by a text-mining pipeline. The quality of the data was manually evaluated, and was found to be of high accuracy (estimated precision >86%). Furthermore, grouping together diseases that share similar age patterns in mice resulted in clusters that mirror actual biomedical knowledge. Using these data, we matched age distribution patterns in mice and in humans, allowing for age differences by shifting either of the patterns. High correlation (r(2)>0.5) was found for 223 diseases. The results clearly indicate a difference in the age mapping between different diseases: age 30 years in human is mapped to 120 days in mice for Leukemia, but to 295 days for Anemia. Based on these results we generated a mice-to-human age map which is publicly available. We present here the development of the mouse-APK, its population with literature-derived data and its use to map ages in mice and human for 223 diseases. These results present a further step made to bridging the gap between humans and mice in biomedical research.

Parental smoking during pregnancy and total and abdominal fat distribution in school-age children: the Generation R Study.

PubMed

Durmuş, B; Heppe, D H M; Taal, H R; Manniesing, R; Raat, H; Hofman, A; Steegers, E A P; Gaillard, R; Jaddoe, V W V

2014-07-01

Fetal smoke exposure may influence growth and body composition later in life. We examined the associations of maternal and paternal smoking during pregnancy with total and abdominal fat distribution in school-age children. We performed a population-based prospective cohort study among 5243 children followed from early pregnancy onward in the Netherlands. Information about parental smoking was obtained by questionnaires during pregnancy. At the median age of 6.0 years (90% range: 5.7-7.4), we measured anthropometrics, total fat and android/gynoid fat ratio by dual-energy X-ray absorptiometry, and preperitoneal and subcutaneous abdominal fat were measured by ultrasound. The associations of maternal smoking during pregnancy were only present among girls (P-value for sex interaction<0.05). Compared with girls from mothers who did not smoke during pregnancy, those from mothers who smoked during the first trimester only had a higher android/gynoid fat ratio (difference 0.23 (95% confidence interval (CI): 0.09-0.37) s.d. scores (SDS). Girls from mothers who continued smoking throughout pregnancy had a higher body mass index (difference: 0.24 (95% CI: 0.14-0.35) SDS), total fat mass (difference: 0.23 (95% CI: 0.14-0.33) SDS), android/gynoid fat ratio (difference: 0.34 (95% CI: 0.22-0.46) SDS), subcutaneous abdominal fat (difference: 0.22 (95% CI: 0.11-0.33) SDS) and preperitoneal abdominal fat (difference: 0.20 (95% CI: 0.08-0.31) SDS). Similar associations with body fat distribution outcomes were observed for paternal smoking during pregnancy. Both continued maternal and paternal smoking during pregnancy may be associated with an increased risk of childhood overweight. The corresponding odds ratios were 1.19 (95% CI: 0.98-1.46) and 1.32 (1.10-1.58), respectively. Maternal and paternal smoking during pregnancy are associated with an adverse body and abdominal fat distribution and increased risk of overweight in children. Similar effects of maternal and paternal smoking

EFFECTS OF MIXING AND AGING ON WATER QUALITY IN DISTRIBUTION SYSTEM STORAGE FACILITIES

EPA Science Inventory

Aging of water in distribution system storage facilities can lead to deterioration of the water quality due to loss of disinfectant residual and bacterial regrowth. Facilities should be operated to insure that the age of the water is not excessive taking into account the quality...

Estimating the formation age distribution of continental crust by unmixing zircon ages

NASA Astrophysics Data System (ADS)

Korenaga, Jun

2018-01-01

Continental crust provides first-order control on Earth's surface environment, enabling the presence of stable dry landmasses surrounded by deep oceans. The evolution of continental crust is important for atmospheric evolution, because continental crust is an essential component of deep carbon cycle and is likely to have played a critical role in the oxygenation of the atmosphere. Geochemical information stored in the mineral zircon, known for its resilience to diagenesis and metamorphism, has been central to ongoing debates on the genesis and evolution of continental crust. However, correction for crustal reworking, which is the most critical step when estimating original formation ages, has been incorrectly formulated, undermining the significance of previous estimates. Here I suggest a simple yet promising approach for reworking correction using the global compilation of zircon data. The present-day distribution of crustal formation age estimated by the new "unmixing" method serves as the lower bound to the true crustal growth, and large deviations from growth models based on mantle depletion imply the important role of crustal recycling through the Earth history.

Similarity-based interference in a working memory numerical updating task: age-related differences between younger and older adults.

PubMed

Pelegrina, Santiago; Borella, Erika; Carretti, Barbara; Lechuga, M Teresa

2012-01-01

Similarity among representations held simultaneously in working memory (WM) is a factor which increases interference and hinders performance. The aim of the current study was to investigate age-related differences between younger and older adults in a working memory numerical updating task, in which the similarity between information held in WM was manipulated. Results showed a higher susceptibility of older adults to similarity-based interference when accuracy, and not response times, was considered. It was concluded that older adults' WM difficulties appear to be due to the availability of stored information, which, in turn, might be related to the ability to generate distinctive representations and to the process of binding such representations to their context when similar information has to be processed in WM.

Age-related changes in abdominal fat distribution in Japanese adults in the general population.

PubMed

Sugihara, Masako; Oka, Rie; Sakurai, Masaru; Nakamura, Koshi; Moriuchi, Tadashi; Miyamoto, Susumu; Takeda, Yoshiyu; Yagi, Kunimasa; Yamagishi, Masakazu

2011-01-01

Early studies have indicated that body fat shifts from peripheral stores to central stores with aging. The objective of this study was to investigate age-related changes in abdominal fat distribution of Japanese men and women of the general population over a wide range of body mass indices (BMI). A total of 2,220 non-diabetic, apparently healthy Japanese adults (1,240 men and 980 women; age range 40-69 years) were included in the study sample. All subjects underwent a CT scan at the level of the umbilicus, and the areas of visceral adipose tissue (AT) and subcutaneous AT were quantified. When the subjects were stratified by BMI into 18.5-23.0 kg/m(2), 23.0-27.5 kg/m(2), and 27.5 kg/m(2) or higher, visceral AT was positively correlated with age in all of the BMI strata in both genders (p<0.01). In contrast, subcutaneous AT was negatively correlated with age in men with BMIs in excess of 23.0 kg/m(2) (p<0.01) and not at all in women. The mean levels of subcutaneous AT were over 2-fold greater than visceral AT in women aged 60-69 years in any BMI stratum. In Japanese men and women, visceral AT was increased with age in all BMI strata in both genders, whereas subcutaneous AT was decreased with age in men with BMIs in excess of 23.0 kg/m(2) and not at all in women. Even with these age-related changes in abdominal fat distribution, women retained the subcutaneous-dominant type of fat distribution up to 70 years.

Friedman tongue position: age distribution and relationship to sleep-disordered breathing.

PubMed

Ingram, David G; Ruiz, Amanda; Friedman, Norman R

2015-05-01

Friedman tongue position (FTP) may play an important role in the evaluation of children with sleep-related breathing disorders (SRBD), but there are no previous data on FTP distribution by age. The objective of the current study was to determine the distribution of FTP by age and examine the relationship between FTP and snoring in children. Prospective cross-sectional study of 199 children (mean age, 6.8 years; 59% male) had tongue position assessed by FTP as part of their clinical examination of the oral cavity during routine ENT visits at a tertiary care children's hospital. The FTP and snoring frequency of participants was examined across the entire age range as well as by comparing those older (middle childhood and above) and younger than 5 years of age. Tongue position did not correlate with age or snoring frequency. The proportion of children with FTP III/IV was not significantly different in children younger than five years of age compared to older than five. Habitual snoring was not associated with having a higher FTP. Among children who snored <3 times per week, those who had previously undergone tonsillectomy did have higher FTP compared to those who had not (p=0.007). BMI-%-for-age was significantly correlated with FTP (p=0.003). The percent of children having FTP class III/IV differed significantly between ethnicities (22% of whites, 26% of others, 45% of hispanics, 53% of African-Americans; p=0.011). Inter-rater reliability among pediatric otolaryngologist was excellent (kappa=0.93, p<0.001). There does not appear to be an association between FTP with age or snoring frequency in children. The excellent inter-rater reliability for FTP among pediatric ENT providers suggests the null findings are not due to rater bias. These findings may serve as an important reference for those studying the role of tongue position in pediatric SRBD and complement previous studies examining FTP among children with known OSA or snoring. Copyright © 2015 Elsevier Ireland

A partial exponential lumped parameter model to evaluate groundwater age distributions and nitrate trends in long-screened wells

USGS Publications Warehouse

Jurgens, Bryant; Böhlke, John Karl; Kauffman, Leon J.; Belitz, Kenneth; Esser, Bradley K.

2016-01-01

A partial exponential lumped parameter model (PEM) was derived to determine age distributions and nitrate trends in long-screened production wells. The PEM can simulate age distributions for wells screened over any finite interval of an aquifer that has an exponential distribution of age with depth. The PEM has 3 parameters – the ratio of saturated thickness to the top and bottom of the screen and mean age, but these can be reduced to 1 parameter (mean age) by using well construction information and estimates of the saturated thickness. The PEM was tested with data from 30 production wells in a heterogeneous alluvial fan aquifer in California, USA. Well construction data were used to guide parameterization of a PEM for each well and mean age was calibrated to measured environmental tracer data (3H, 3He, CFC-113, and 14C). Results were compared to age distributions generated for individual wells using advective particle tracking models (PTMs). Age distributions from PTMs were more complex than PEM distributions, but PEMs provided better fits to tracer data, partly because the PTMs did not simulate 14C accurately in wells that captured varying amounts of old groundwater recharged at lower rates prior to groundwater development and irrigation. Nitrate trends were simulated independently of the calibration process and the PEM provided good fits for at least 11 of 24 wells. This work shows that the PEM, and lumped parameter models (LPMs) in general, can often identify critical features of the age distributions in wells that are needed to explain observed tracer data and nonpoint source contaminant trends, even in systems where aquifer heterogeneity and water-use complicate distributions of age. While accurate PTMs are preferable for understanding and predicting aquifer-scale responses to water use and contaminant transport, LPMs can be sensitive to local conditions near individual wells that may be inaccurately represented or missing in an aquifer-scale flow model.

Effects of edge contrast on redback salamander distribution in even-aged northern hardwoods

Treesearch

Richard M. DeGraaf; Mariko Yamasaki

2002-01-01

Terrestrial salamanders are sensitive to forest disturbance associated with even-aged management. We studied the distribution of redback salamanders (Plethodon cinereus) for 4 yr at edges between even-aged northern hardwood stands along three replicate transects in each of three edge contrast types: regeneration/mature, sapling/mature, and...

Soil organic matter persistence as a stochastic process: age and transit time distributions of carbon in soils

NASA Astrophysics Data System (ADS)

Sierra, Carlos

2017-04-01

The question of why some organic matter is more persistent than other that decomposes quickly in soils has sparkled a large amount of research in recent years. Persistence is commonly characterized as the turnover or mean residence time of specific compounds or soil organic matter (SOM) pools. However, turnover and residence times are ambiguous measures of persistence, which is better characterized by the probability distribution of ages in the system and in particular pools. We calculated age distributions for a wide range of SOM models, which showed long-tail distributions far from the mean value. Age and transit time distributions from a variety of models also showed: 1) transit times are lower than ages of SOM, 2) turnover times differ significantly from mean ages in slow cycling pools, 3) change in the inputs, without changes in the allocation of photosynthetic products, has no effect on transit times, but does affect system and pool ages. We propose an index to assess persistence of C in soils that can be derived from observations alone or from models. We also ask whether random chance is an important contributor to the persistence of SOM.

[Maternal mortality in Spain, 1980-1992. Relationship with birth distributions according to the mother's age].

PubMed

Valero Juan, L F; Sáenz González, M C

1997-11-01

The maternal mortality evolution in Spain during the 1980-1992 period is reported. The influence of birth distribution according to maternal age is analyzed. The information was gathered from vital statistics published by Instituto Nacional de Estadística. The mortality rates have stabilized since 1985 (4.8 per 10(5) for 1992) associated with the increase in the proportion of births in women aged > or = 30 years (40.6% for 1992). Birth distributions according to maternal age account for 13.1% of the deaths observed. The predictions point to an increase in maternal mortality for the year 2000.

Composition and similarity of global anomodont-bearing tetrapod faunas

NASA Astrophysics Data System (ADS)

Fröbisch, Jörg

2009-08-01

Anomodont synapsids represent the dominant herbivores of Permian and Triassic terrestrial vertebrate ecosystems. Their taxonomic diversity and morphological disparity in combination with their cosmopolitan distribution makes them an ideal study object for macroevolutionary patterns across the most devastating extinction event in earth history. This study provides a thorough review of anomodont-bearing tetrapod faunas to form the basis for a faunal similarity analysis and future studies of anomodont diversity. The stratigraphic correlation and composition of all known anomodont assemblages is revisited, including a discussion of the validity of the globally distributed anomodont species. The similarity analysis of anomodont faunas is performed on the basis of presence-absence data of anomodont taxa, using explorative methods such as cluster analysis (UPGMA) and non-metric multidimensional scaling (NMDS). The recovered faunal groupings indicate a common biostratigraphic age and furthermore reflect biogeographic patterns. Even though endemism and faunal provinciality was a constant element in anomodont faunas of the Permian and Triassic, the available evidence indicates that the end-Permian extinction resulted in a distinct uniformity that was unique to Early Triassic anomodont faunas. This is in particular characterized by the global distribution and overwhelming abundance of the disaster taxon Lystrosaurus. In contrast, cosmopolitan anomodonts also existed in the Late Permian (e.g., Diictodon) and Middle Triassic (e.g., Shansiodon), but those taxa coexisted with endemic faunal elements rather than dominated the fauna as Lystrosaurus did.

Age-related similarities and differences in monitoring spatial cognition.

PubMed

Ariel, Robert; Moffat, Scott D

2018-05-01

Spatial cognitive performance is impaired in later adulthood but it is unclear whether the metacognitive processes involved in monitoring spatial cognitive performance are also compromised. Inaccurate monitoring could affect whether people choose to engage in tasks that require spatial thinking and also the strategies they use in spatial domains such as navigation. The current experiment examined potential age differences in monitoring spatial cognitive performance in a variety of spatial domains including visual-spatial working memory, spatial orientation, spatial visualization, navigation, and place learning. Younger and older adults completed a 2D mental rotation test, 3D mental rotation test, paper folding test, spatial memory span test, two virtual navigation tasks, and a cognitive mapping test. Participants also made metacognitive judgments of performance (confidence judgments, judgments of learning, or navigation time estimates) on each trial for all spatial tasks. Preference for allocentric or egocentric navigation strategies was also measured. Overall, performance was poorer and confidence in performance was lower for older adults than younger adults. In most spatial domains, the absolute and relative accuracy of metacognitive judgments was equivalent for both age groups. However, age differences in monitoring accuracy (specifically relative accuracy) emerged in spatial tasks involving navigation. Confidence in navigating for a target location also mediated age differences in allocentric navigation strategy use. These findings suggest that with the possible exception of navigation monitoring, spatial cognition may be spared from age-related decline even though spatial cognition itself is impaired in older age.

General Similarities but Consistent Differences Between Early- and Late-Onset Depression Among Korean Adults Aged 40 and Older.

PubMed

Park, Jee Eun; Sohn, Ji Hoon; Seong, Su Jeong; Suk, Hye Won; Cho, Maeng Je

2015-08-01

Differences in clinical characteristics, symptomatology, and psychiatric comorbidity between early-onset depression (EOD) and late-onset depression (LOD) were examined in a nationwide representative sample. The Korean Composite International Diagnostic Interview was used to investigate psychiatric diagnoses and age of onset. A total of 319 subjects aged 40 years and older with a current major depressive disorder (MDD) were included, and both a continuous and a dichotomous (40 years) age-of-onset indicator were used in the analyses. Despite general similarities between groups, EOD was related to chronic (recurrent and longer episode) and severe (higher lifetime suicidality) clinical features. Hypersomnia and suicidal plans/attempts were associated with EOD, whereas anhedonia was related to LOD. Lifetime generalized anxiety disorder was associated with EOD, whereas dysthymic disorder was related with higher age of MDD onset. This study provides additional evidence of consistent differences between EOD and LOD among middle-aged and older Asians.

Comparison of fungiform taste-bud distribution among age groups using confocal laser scanning microscopy in vivo in combination with gustatory function.

PubMed

Saito, Takehisa; Ito, Tetsufumi; Ito, Yumi; Manabe, Yasuhiro; Sano, Kazuo

2016-04-01

The aim of this study was to compare the distribution of taste buds in fungiform papillae (FP) and gustatory function between young and elderly age groups. Confocal laser scanning microscopy was used because it allows many FP to be observed non-invasively in a short period of time. The age of participants (n = 211) varied from 20 to 83 yr. The tip and midlateral region of the tongue were observed. Taste buds in an average of 10 FP in each area were counted. A total of 2,350 FP at the tongue tip and 2,592 FP in the midlateral region could be observed. The average number of taste buds was similar among all age groups both at the tongue tip and in the midlateral region. The taste function, measured by electrogustometry, among participants 20-29 yr of age was significantly lower than that in the other age groups; however, there was no difference among any other age groups in taste function. These results indicate that the peripheral gustatory system is well maintained anatomically and functionally in elderly people. © 2016 Eur J Oral Sci.

How old is this bird? The age distribution under some phase sampling schemes.

PubMed

Hautphenne, Sophie; Massaro, Melanie; Taylor, Peter

2017-12-01

In this paper, we use a finite-state continuous-time Markov chain with one absorbing state to model an individual's lifetime. Under this model, the time of death follows a phase-type distribution, and the transient states of the Markov chain are known as phases. We then attempt to provide an answer to the simple question "What is the conditional age distribution of the individual, given its current phase"? We show that the answer depends on how we interpret the question, and in particular, on the phase observation scheme under consideration. We then apply our results to the computation of the age pyramid for the endangered Chatham Island black robin Petroica traversi during the monitoring period 2007-2014.

Age-dependent trigeminal and female-specific lumbosacral increase in herpes zoster distribution in the elderly.

PubMed

Shiraki, Kimiyasu; Toyama, Nozomu; Shiraki, Atsuko; Yajima, Misako

2018-05-01

Varicella-zoster virus causes herpes zoster (HZ) along specific dermatomes, but the effects of age and sex on HZ distribution are unclear. We investigated the age- and sex-dependent distribution characteristics of HZ. Patients with HZ were monitored by members of the Miyazaki Dermatologist Society. Questionnaires containing information on age, sex, and dermatome distribution and lesion specimens from 2730 patients were collected, and 2508 PCR-diagnosed cases were analyzed. The ratio of lesions in the thoracic area to lesions in the whole body decreased with age, whereas those of other areas increased. HZ incidence increased with age to about four times that of the basic incidence in the dermatome areas at age 0-29 years; the incidence in the trigeminal area in both sexes increased 11-fold, and the incidence in the thoracic and lumbosacral areas increased in females more than in males. Furthermore, the fact that the highest incidence was found along the first branch of the trigeminal nerve suggests an association with long-term ultraviolet ray exposure. Segmental dermatomes comprising thoracic 10-lumbar 1/sacral 2-4 and thoracic 5-6 were significantly more frequently affected in female patients at age 50-59 years and are consistent with areas of obstetric anesthesia for childbirth and of breastfeeding, respectively. HZ incidence increased with age; moreover, exposure to ultraviolet rays, childbirth, and breastfeeding might increase the incidence at specific dermatomes in older individuals. This study provides important information on the etiology of HZ. Copyright © 2018 Japanese Society for Investigative Dermatology. Published by Elsevier B.V. All rights reserved.

TracerLPM (Version 1): An Excel® workbook for interpreting groundwater age distributions from environmental tracer data

USGS Publications Warehouse

Jurgens, Bryant C.; Böhlke, J.K.; Eberts, Sandra M.

2012-01-01

TracerLPM is an interactive Excel® (2007 or later) workbook program for evaluating groundwater age distributions from environmental tracer data by using lumped parameter models (LPMs). Lumped parameter models are mathematical models of transport based on simplified aquifer geometry and flow configurations that account for effects of hydrodynamic dispersion or mixing within the aquifer, well bore, or discharge area. Five primary LPMs are included in the workbook: piston-flow model (PFM), exponential mixing model (EMM), exponential piston-flow model (EPM), partial exponential model (PEM), and dispersion model (DM). Binary mixing models (BMM) can be created by combining primary LPMs in various combinations. Travel time through the unsaturated zone can be included as an additional parameter. TracerLPM also allows users to enter age distributions determined from other methods, such as particle tracking results from numerical groundwater-flow models or from other LPMs not included in this program. Tracers of both young groundwater (anthropogenic atmospheric gases and isotopic substances indicating post-1940s recharge) and much older groundwater (carbon-14 and helium-4) can be interpreted simultaneously so that estimates of the groundwater age distribution for samples with a wide range of ages can be constrained. TracerLPM is organized to permit a comprehensive interpretive approach consisting of hydrogeologic conceptualization, visual examination of data and models, and best-fit parameter estimation. Groundwater age distributions can be evaluated by comparing measured and modeled tracer concentrations in two ways: (1) multiple tracers analyzed simultaneously can be evaluated against each other for concordance with modeled concentrations (tracer-tracer application) or (2) tracer time-series data can be evaluated for concordance with modeled trends (tracer-time application). Groundwater-age estimates can also be obtained for samples with a single tracer measurement at one

An objective method to determine the probability distribution of the minimum apparent age of a sample of radio-isotopic dates

NASA Astrophysics Data System (ADS)

Ickert, R. B.; Mundil, R.

2012-12-01

points while being resistant to outliers, it utilizes the measurement uncertainties, and it does not require the assumption that any given cluster of data represents a single geological event. In brief, the technique generates a synthetic distribution from the input data by resampling with replacement (a bootstrap). Each resample is a random selection from a Gaussian distribution defined by the mean and uncertainty of the data point. For this distribution, the minimum value is calculated. This procedure is repeated many times (>1000) and a distribution of minimum values is generated, from which a confidence interval can be constructed. We demonstrate the application of this technique using natural and synthetic datasets, show the advantages and limitations, and relate it to other methods. We emphasize that this estimate remains strictly a minimum age - as with any other estimate that does not explicitly incorporate lag or residence time, it will not reflect a depositional age if the lag/residence time is larger than the uncertainty of the estimate. We recommend that this or similar techniques be considered by geochronologists. Ludwig, K.R., 2012. Isoplot 3.75, A geochronological toolkit for Microsoft Excel; Berkeley Geochronology Center Special Publication no. 5

Floodplain dynamics control the age distribution of organic carbon in large rivers

NASA Astrophysics Data System (ADS)

Torres, M. A.; Limaye, A. B. S.; Ganti, V.; West, A. J.; Fischer, W. W.; Lamb, M. P.

2016-12-01

As sediments transit through river systems, they are temporarily stored within floodplains. This storage is important for geochemical cycles because it imparts a certain cadence to weathering processes and organic carbon cycling. However, the time and length scales over which these processes operate are poorly known. To address this, we developed a model for the distribution of storage times in floodplains and used it to make predictions of the age distribution of riverine particulate organic carbon (POC) that can be compared with data from a range of rivers.Using statistics generated from a numerical model of river meandering that accounts for the rates of lateral channel migration and the lengths of channel needed to exchange the sediment flux with the floodplain, we estimated the distribution of sediment storage times. Importantly, this approach consistently yields a heavy-tailed distribution of storage times. This finding, based on comprehensive simulations of a wide range of river conditions, arises because of geometrical constraints that lead to the preferential erosion and reworking of young deposits. To benchmark our model, we compared our results with meteoric 10Be data (a storage time proxy) from Amazonian rivers. Our model correctly predicts observed 10Be concentrations, and consequently appears to capture the correct characteristic timescales associated with floodplain storage. By coupling a simple model of carbon cycling with our floodplain storage model, we are able to make predictions about the radiocarbon content of riverine POC. We observe that floodplains with greater storage times tend to have biospheric POC with a lower radiocarbon content (after correcting bulk ages for contribution from radiocarbon-dead petrogenic carbon). This result confirms that storage plays a key role in setting the age of POC transported by rivers with important implications for the dynamics of the global carbon cycle.

Aging ballistic Lévy walks

NASA Astrophysics Data System (ADS)

Magdziarz, Marcin; Zorawik, Tomasz

2017-02-01

Aging can be observed for numerous physical systems. In such systems statistical properties [like probability distribution, mean square displacement (MSD), first-passage time] depend on a time span ta between the initialization and the beginning of observations. In this paper we study aging properties of ballistic Lévy walks and two closely related jump models: wait-first and jump-first. We calculate explicitly their probability distributions and MSDs. It turns out that despite similarities these models react very differently to the delay ta. Aging weakly affects the shape of probability density function and MSD of standard Lévy walks. For the jump models the shape of the probability density function is changed drastically. Moreover for the wait-first jump model we observe a different behavior of MSD when ta≪t and ta≫t .

Effects of age condition on the distribution and integrity of inorganic fillers in dental resin composites.

PubMed

D'Alpino, Paulo Henrique Perlatti; Svizero, Nádia da Rocha; Bim Júnior, Odair; Valduga, Claudete Justina; Graeff, Carlos Frederico de Oliveira; Sauro, Salvatore

2016-06-01

The aim of this study is to evaluate the distribution of the filler size along with the zeta potential, and the integrity of silane-bonded filler surface in different types of restorative dental composites as a function of the material age condition. Filtek P60 (hybrid composite), Filtek Z250 (small-particle filled composite), Filtek Z350XT (nanofilled composite), and Filtek Silorane (silorane composite) (3M ESPE) were tested at different stage condition (i.e., fresh/new, aged, and expired). Composites were submitted to an accelerated aging protocol (Arrhenius model). Specimens were obtained by first diluting each composite specimen in ethanol and then dispersed in potassium chloride solution (0.001 mol%). Composite fillers were characterized for their zeta potential, mean particle size, size distribution, via poly-dispersion dynamic light scattering. The integrity of the silane-bonded surface of the fillers was characterized by FTIR. The material age influenced significantly the outcomes; Zeta potential, filler characteristics, and silane integrity varied both after aging and expiration. Silorane presented the broadest filler distribution and lowest zeta potential. Nanofilled and silorane composites exhibited decreased peak intensities in the FTIR analysis, indicating a deficiency of the silane integrity after aging or expiry time. Regardless to the material condition, the hybrid and the small-particle-filled composites were more stable overtime as no significant alteration in filler size distribution, diameter, and zeta potential occurred. A deficiency in the silane integrity in the nanofilled and silorane composites seems to be affected by the material stage condition. The materials conditions tested in this study influenced the filler size distribution, the zeta potential, and integrity of the silane adsorbed on fillers in the nanofilled and silorane composites. Thus, this may result in a decrease of the clinical performance of aforementioned composites, in

Self-similar structure and experimental signatures of suprathermal ion distribution in inertial confinement fusion implosions

DOE PAGES

Kagan, Grigory; Svyatskiy, D.; Rinderknecht, H. G.; ...

2015-09-03

The distribution function of suprathermal ions is found to be self-similar under conditions relevant to inertial confinement fusion hot spots. By utilizing this feature, interference between the hydrodynamic instabilities and kinetic effects is for the first time assessed quantitatively to find that the instabilities substantially aggravate the fusion reactivity reduction. Thus, the ion tail depletion is also shown to lower the experimentally inferred ion temperature, a novel kinetic effect that may explain the discrepancy between the exploding pusher experiments and rad-hydro simulations and contribute to the observation that temperature inferred from DD reaction products is lower than from DT atmore » the National Ignition Facility.« less

Self-Similar Structure and Experimental Signatures of Suprathermal Ion Distribution in Inertial Confinement Fusion Implosions

NASA Astrophysics Data System (ADS)

Kagan, Grigory; Svyatskiy, D.; Rinderknecht, H. G.; Rosenberg, M. J.; Zylstra, A. B.; Huang, C.-K.; McDevitt, C. J.

2015-09-01

The distribution function of suprathermal ions is found to be self-similar under conditions relevant to inertial confinement fusion hot spots. By utilizing this feature, interference between the hydrodynamic instabilities and kinetic effects is for the first time assessed quantitatively to find that the instabilities substantially aggravate the fusion reactivity reduction. The ion tail depletion is also shown to lower the experimentally inferred ion temperature, a novel kinetic effect that may explain the discrepancy between the exploding pusher experiments and rad-hydro simulations and contribute to the observation that temperature inferred from DD reaction products is lower than from DT at the National Ignition Facility.

The dependence of stellar age distributions on giant molecular cloud environment

NASA Astrophysics Data System (ADS)

Dobbs, C. L.; Pringle, J. E.; Naylor, T.

2014-01-01

In this Letter, we analyse the distributions of stellar ages in giant molecular clouds (GMCs) in spiral arms, interarm spurs and at large galactic radii, where the spiral arms are relatively weak. We use the results of numerical simulations of galaxies, which follow the evolution of GMCs and include star particles where star formation events occur. We find that GMCs in spiral arms tend to have predominantly young (<10 Myr) stars. By contrast, clouds which are the remainders of spiral arm giant molecular asssociations that have been sheared into interarm GMCs contain fewer young (<10 Myr) stars and more ˜20 Myr stars. We also show that clouds which form in the absence of spiral arms, due to local gravitational and thermal instabilities, contain preferentially young stars. We propose that the age distributions of stars in GMCs will be a useful diagnostic to test different cloud evolution scenarios, the origin of spiral arms and the success of numerical models of galactic star formation. We discuss the implications of our results in the context of Galactic and extragalactic molecular clouds.

Surface similarity-based molecular query-retrieval

PubMed Central

Singh, Rahul

2007-01-01

Background Discerning the similarity between molecules is a challenging problem in drug discovery as well as in molecular biology. The importance of this problem is due to the fact that the biochemical characteristics of a molecule are closely related to its structure. Therefore molecular similarity is a key notion in investigations targeting exploration of molecular structural space, query-retrieval in molecular databases, and structure-activity modelling. Determining molecular similarity is related to the choice of molecular representation. Currently, representations with high descriptive power and physical relevance like 3D surface-based descriptors are available. Information from such representations is both surface-based and volumetric. However, most techniques for determining molecular similarity tend to focus on idealized 2D graph-based descriptors due to the complexity that accompanies reasoning with more elaborate representations. Results This paper addresses the problem of determining similarity when molecules are described using complex surface-based representations. It proposes an intrinsic, spherical representation that systematically maps points on a molecular surface to points on a standard coordinate system (a sphere). Molecular surface properties such as shape, field strengths, and effects due to field super-positioningcan then be captured as distributions on the surface of the sphere. Surface-based molecular similarity is subsequently determined by computing the similarity of the surface-property distributions using a novel formulation of histogram-intersection. The similarity formulation is not only sensitive to the 3D distribution of the surface properties, but is also highly efficient to compute. Conclusion The proposed method obviates the computationally expensive step of molecular pose-optimisation, can incorporate conformational variations, and facilitates highly efficient determination of similarity by directly comparing molecular surfaces

Document similarity measures and document browsing

NASA Astrophysics Data System (ADS)

Ahmadullin, Ildus; Fan, Jian; Damera-Venkata, Niranjan; Lim, Suk Hwan; Lin, Qian; Liu, Jerry; Liu, Sam; O'Brien-Strain, Eamonn; Allebach, Jan

2011-03-01

Managing large document databases is an important task today. Being able to automatically com- pare document layouts and classify and search documents with respect to their visual appearance proves to be desirable in many applications. We measure single page documents' similarity with respect to distance functions between three document components: background, text, and saliency. Each document component is represented as a Gaussian mixture distribution; and distances between dierent documents' components are calculated as probabilistic similarities between corresponding distributions. The similarity measure between documents is represented as a weighted sum of the components' distances. Using this document similarity measure, we propose a browsing mechanism operating on a document dataset. For these purposes, we use a hierarchical browsing environment which we call the document similarity pyramid. It allows the user to browse a large document dataset and to search for documents in the dataset that are similar to the query. The user can browse the dataset on dierent levels of the pyramid, and zoom into the documents that are of interest.

Influence of pedestrian age and gender on spatial and temporal distribution of pedestrian crashes.

PubMed

Toran Pour, Alireza; Moridpour, Sara; Tay, Richard; Rajabifard, Abbas

2018-01-02

Every year, about 1.24 million people are killed in traffic crashes worldwide and more than 22% of these deaths are pedestrians. Therefore, pedestrian safety has become a significant traffic safety issue worldwide. In order to develop effective and targeted safety programs, the location- and time-specific influences on vehicle-pedestrian crashes must be assessed. The main purpose of this research is to explore the influence of pedestrian age and gender on the temporal and spatial distribution of vehicle-pedestrian crashes to identify the hotspots and hot times. Data for all vehicle-pedestrian crashes on public roadways in the Melbourne metropolitan area from 2004 to 2013 are used in this research. Spatial autocorrelation is applied in examining the vehicle-pedestrian crashes in geographic information systems (GIS) to identify any dependency between time and location of these crashes. Spider plots and kernel density estimation (KDE) are then used to determine the temporal and spatial patterns of vehicle-pedestrian crashes for different age groups and genders. Temporal analysis shows that pedestrian age has a significant influence on the temporal distribution of vehicle-pedestrian crashes. Furthermore, men and women have different crash patterns. In addition, results of the spatial analysis shows that areas with high risk of vehicle-pedestrian crashes can vary during different times of the day for different age groups and genders. For example, for those between ages 18 and 65, most vehicle-pedestrian crashes occur in the central business district (CBD) during the day, but between 7:00 p.m. and 6:00 a.m., crashes among this age group occur mostly around hotels, clubs, and bars. This research reveals that temporal and spatial distributions of vehicle-pedestrian crashes vary for different pedestrian age groups and genders. Therefore, specific safety measures should be in place during high crash times at different locations for different age groups and genders to

Reconstructing merger timelines using star cluster age distributions: the case of MCG+08-11-002

NASA Astrophysics Data System (ADS)

Davies, Rebecca L.; Medling, Anne M.; U, Vivian; Max, Claire E.; Sanders, David; Kewley, Lisa J.

2016-05-01

We present near-infrared imaging and integral field spectroscopy of the centre of the dusty luminous infrared galaxy merger MCG+08-11-002, taken using the Near InfraRed Camera 2 (NIRC2) and the OH-Suppressing InfraRed Imaging Spectrograph (OSIRIS) on Keck II. We achieve a spatial resolution of ˜25 pc in the K band, allowing us to resolve 41 star clusters in the NIRC2 images. We calculate the ages of 22/25 star clusters within the OSIRIS field using the equivalent widths of the CO 2.3 μm absorption feature and the Br γ nebular emission line. The star cluster age distribution has a clear peak at ages ≲ 20 Myr, indicative of current starburst activity associated with the final coalescence of the progenitor galaxies. There is a possible second peak at ˜65 Myr which may be a product of the previous close passage of the galaxy nuclei. We fit single and double starburst models to the star cluster age distribution and use Monte Carlo sampling combined with two-sided Kolmogorov-Smirnov tests to calculate the probability that the observed data are drawn from each of the best-fitting distributions. There is a >90 per cent chance that the data are drawn from either a single or double starburst star formation history, but stochastic sampling prevents us from distinguishing between the two scenarios. Our analysis of MCG+08-11-002 indicates that star cluster age distributions provide valuable insights into the timelines of galaxy interactions and may therefore play an important role in the future development of precise merger stage classification systems.

Height and the normal distribution: evidence from Italian military data.

PubMed

A'Hearn, Brian; Peracchi, Franco; Vecchi, Giovanni

2009-02-01

Researchers modeling historical heights have typically relied on the restrictive assumption of a normal distribution, only the mean of which is affected by age, income, nutrition, disease, and similar influences. To avoid these restrictive assumptions, we develop a new semiparametric approach in which covariates are allowed to affect the entire distribution without imposing any parametric shape. We apply our method to a new database of height distributions for Italian provinces, drawn from conscription records, of unprecedented length and geographical disaggregation. Our method allows us to standardize distributions to a single age and calculate moments of the distribution that are comparable through time. Our method also allows us to generate counterfactual distributions for a range of ages, from which we derive age-height profiles. These profiles reveal how the adolescent growth spurt (AGS) distorts the distribution of stature, and they document the earlier and earlier onset of the AGS as living conditions improved over the second half of the nineteenth century. Our new estimates of provincial mean height also reveal a previously unnoticed "regime switch "from regional convergence to divergence in this period.

Mind the gap: the distributional effects of raising the early eligibility age and full retirement age.

PubMed

Olsen, Anya

2012-01-01

Policymakers have proposed increases to the early eligibility age (EEA) and/or full retirement age (FRA) to address increasing life expectancy and Social Security solvency issues. This analysis uses the Social Security Administration's Modeling Income in the Near Term, version 6 (MINT6) model to compare three retirement-age increases suggested by the Social Security Advisory Board: increase the gap between the EEA and FRA by raising only the FRA, increase both the EEA and FRA to maintain a 4-year gap between them, and increase both the EEA and FRA to maintain a 5-year gap between them. Although all three options would improve system solvency by similar proportions, their effect on individual beneficiaries in the future would vary. Benefit reductions are greater under the proposals with more months between the EEA and FRA, while the option that maintains a 4-year gap results in benefit increases for some beneficiaries compared with current law.

Age and sex distribution in malignant and tuberculous serous effusions: A study of 127 patients and review of the literature.

PubMed

Das, Dilip K

2015-09-01

Tuberculosis and carcinomatosis are the two most frequent causes of pleural effusion and exudative ascites, and both are characterized by lymphocyte-rich effusion. We attempted to discover if there is any significant difference in the age and sex distribution between patients presenting with these two conditions. A total of 161 serous effusion samples from 127 patients (89 with pleural effusion and 38 with ascites) having follow-up biopsy and histopathological examination were included in the present study. Three groups - malignancy (47 patients), tuberculosis (47) and non-tuberculous benign lesions (26) as per histopathological diagnoses - were compared in respect to age and sex distribution. A total of 29 (61.7%) patients with malignancy were aged ≥50 years as compared with three (6.4%) tuberculosis patients with serous effusions (P = 0.00000). A similar trend was observed in the ≥60 years age group (18 or 38.3% malignancy vs none with tuberculosis, P = 0.00000). A total of 36 (76.6%) tuberculous effusion patients were aged less than 40 years as opposed to eight (17.0%) patients with malignant effusions (P = 0.00000). There was also s significant difference between tuberculous and non-tuberculous benign lesions in the ≥50 years age group (6.4% vs 69.2%, P = 0.00000), but no significant difference between malignancy and non-tuberculous benign lesions (P = 0.61385). There were 31 female (66.0%) patients with malignancy, which was significantly higher than that of patients with tuberculosis (16, [34%], P = 0.00365) and non-specific inflammation/benign lesions (23.1%, P = 0.00059). However, the difference between tuberculosis and non-tuberculous benign lesions was not significant (P = 0.42756). Whereas malignancy in serous effusions is found in older and middle-aged people, tuberculous effusion is a disease of younger people. © 2014 Japan Geriatrics Society.

A twelve-year comparison of stand changes in a mahogany plantation and a paired natural forest of similar ages.

Treesearch

S. Fu; C. Rodr¡guez Pedraza; A. E. Lugo

1996-01-01

we compared forest structure over a 12 yr period. 1982-1994 that include measurements before and after a servere hurricaine in two forests: a 64 yr old swietenia macrophylla tree plantantion and a paired natural forest of similar age in a subtropical wet forests

Investigating the age distribution of fracture discharge using multiple environmental tracers, Bedrichov Tunnel, Czech Republic

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gardner, W. Payton; Hokr, Milan; Shao, Hua

We investigated the transit time distribution (TTD) of discharge collected from fractures in the Bedrichov Tunnel, Czech Republic, using lumped parameter models and multiple environmental tracers. We then utilize time series of δ 18O, δ 2H and 3H along with CFC measurements from individual fractures in the Bedrichov Tunnel of the Czech Republic to investigate the TTD, and the uncertainty in estimated mean travel time in several fracture networks of varying length and discharge. We also compare several TTDs, including the dispersion distribution, the exponential distribution, and a developed TTD which includes the effects of matrix diffusion. The effect ofmore » seasonal recharge is explored by comparing several seasonal weighting functions to derive the historical recharge concentration. We identify best fit mean ages for each TTD by minimizing the error-weighted, multi-tracer χ2 residual for each seasonal weighting function. We use this methodology to test the ability of each TTD and seasonal input function to fit the observed tracer concentrations, and the effect of choosing different TTD and seasonal recharge functions on the mean age estimation. We find that the estimated mean transit time is a function of both the assumed TTD and seasonal weighting function. Best fits as measured by the χ2 value were achieved for the dispersion model using the seasonal input function developed here for two of the three modeled sites, while at the third site, equally good fits were achieved with the exponential model and the dispersion model and our seasonal input function. The average mean transit time for all TTDs and seasonal input functions converged to similar values at each location. The sensitivity of the estimated mean transit time to the seasonal weighting function was equal to that of the TTD. These results indicated that understanding seasonality of recharge is at least as important as the uncertainty in the flow path distribution in fracture networks and that

Investigating the age distribution of fracture discharge using multiple environmental tracers, Bedrichov Tunnel, Czech Republic

DOE PAGES

Gardner, W. Payton; Hokr, Milan; Shao, Hua; ...

2016-10-19

We investigated the transit time distribution (TTD) of discharge collected from fractures in the Bedrichov Tunnel, Czech Republic, using lumped parameter models and multiple environmental tracers. We then utilize time series of δ 18O, δ 2H and 3H along with CFC measurements from individual fractures in the Bedrichov Tunnel of the Czech Republic to investigate the TTD, and the uncertainty in estimated mean travel time in several fracture networks of varying length and discharge. We also compare several TTDs, including the dispersion distribution, the exponential distribution, and a developed TTD which includes the effects of matrix diffusion. The effect ofmore » seasonal recharge is explored by comparing several seasonal weighting functions to derive the historical recharge concentration. We identify best fit mean ages for each TTD by minimizing the error-weighted, multi-tracer χ2 residual for each seasonal weighting function. We use this methodology to test the ability of each TTD and seasonal input function to fit the observed tracer concentrations, and the effect of choosing different TTD and seasonal recharge functions on the mean age estimation. We find that the estimated mean transit time is a function of both the assumed TTD and seasonal weighting function. Best fits as measured by the χ2 value were achieved for the dispersion model using the seasonal input function developed here for two of the three modeled sites, while at the third site, equally good fits were achieved with the exponential model and the dispersion model and our seasonal input function. The average mean transit time for all TTDs and seasonal input functions converged to similar values at each location. The sensitivity of the estimated mean transit time to the seasonal weighting function was equal to that of the TTD. These results indicated that understanding seasonality of recharge is at least as important as the uncertainty in the flow path distribution in fracture networks and that

A finite mixture of two Weibull distributions for modeling the diameter distributions of rotated-sigmoid, uneven-aged stands

Treesearch

Lianjun Zhang; Jeffrey H. Gove; Chuangmin Liu; William B. Leak

2001-01-01

The rotated-sigmoid form is a characteristic of old-growth, uneven-aged forest stands caused by past disturbances such as cutting, fire, disease, and insect attacks. The diameter frequency distribution of the rotated-sigmoid form is bimodal with the second rounded peak in the midsized classes, rather than a smooth, steeply descending, monotonic curve. In this study a...

American woodcock winter distribution and fidelity to wintering areas

USGS Publications Warehouse

Diefenbach, D.R.; Derleth, E.L.; Vander Haegen, W. Matthew; Nichols, J.D.; Hines, J.E.

1990-01-01

We examined winter distribution and fidelity to wintering areas for the American Woodcock (Scolopax minor), which exhibits reversed, sexual size dimorphism. Band-recovery data revealed no difference in winter distributions of different age/sex classes for woodcock from the same breeding ares. Similarly, band recoveries from woodcock banded on wintering grounds revealed no difference in fidelity to wintering sites. Males may winter north of a latitude that is optimal for survival based on physiological considerations, but they gain a reproductive advantage if they are among the first to arrive on the breeding grounds. This may explain our results, which indicate males and females have similar distribution patterns during winter.

A new mechanism for aging: chemical "age spots" in immortal DNA strands in distributed stem cells.

PubMed

Sherley, James L

2008-01-01

The existence of immortal DNA strands (IDSs) in distributed stem cells (DSCs) of adult human tissues was first inferred by Cairns. Cairns deduced the existence of IDSs by connecting two seemingly disparate observations - one his own and the other belonging to Lark. Cairns noted a mathematical discrepancy between predicted human tissue cell mutation rates and human cancer incidence. He integrated this insight with Lark's earlier discovery of non-random mitotic chromosome segregation in both plant root tip cells and mouse fetal fibroblast cultures to predict the existence of IDSs as the essential elements of a mutation-defense mechanism in DSCs. Since Cairns' seminal prediction, several laboratories have identified IDSs in diverse mammalian cells with DSC properties. Past studies focused on the potential roles of IDSs as originally envisioned in DSC genetic fidelity or in the maintenance of the DSC phenotype. Another possible consequence of IDSs, aging, has received little attention. Herein, the potential for cumulative chemical modifications and decompositions (i.e., "age spots") of IDSs in DSCs to act as a major determinant of human aging is considered. If accrued chemical alterations of IDSs prove to be essential determinants of aging, then a means to restore IDSs may yield new strategies for tissue rejuvenation.

The influence of age on the distribution, metabolism and excretion of methoxyflurane in Fischer 344 rats: a possible relationship to nephrotoxicity.

PubMed

Bell, L E; Hitt, B A; Mazze, R I

1975-10-01

Age as a factor in methoxyflurane nephrotoxicity was evaluated in Fischer 344 rats of various ages by determination of: 1) serum inorganic fluoride and methoxyflurane concentrations, and urinary inorganic fluoride excretion in methoxyflurane-exposed rats; 2) liver microsomal methoxyflurane defluorinase activity; and 3) distribution of injected sodium fluoride. Only rats in the youngest age group (6 weeks) did not develop nephrotoxicity after anesthesia. Older rats had a biphasic rather than a monophasic decay in serum methoxyflurane concentration and also had increased serum inorganic fluoride concentration and urinary inorganic fluoride excretion. Older rats also excreted a greater proportion of an injected dose of sodium fluoride compared to young rats. Microsomal methoxyflurane defluorinase specific activity was similar among rats of all ages. It is likely that increased availability of methoxyflurane due to its greater storage in fat led to more inorganic fluoride production in older compared to younger rats. Bone sequestration of inorganic fluoride in younger rats probably accounts for decreased serum inorganic fluoride levels in that group. Both factors cause significant differences in renal exposure to inorganic fluoride; thus the risk of nephrotoxicity is less in younger animals.

The age distribution of mortality due to influenza: pandemic and peri-pandemic

PubMed Central

2012-01-01

Background Pandemic influenza is said to 'shift mortality' to younger age groups; but also to spare a subpopulation of the elderly population. Does one of these effects dominate? Might this have important ramifications? Methods We estimated age-specific excess mortality rates for all-years for which data were available in the 20th century for Australia, Canada, France, Japan, the UK, and the USA for people older than 44 years of age. We modeled variation with age, and standardized estimates to allow direct comparison across age groups and countries. Attack rate data for four pandemics were assembled. Results For nearly all seasons, an exponential model characterized mortality data extremely well. For seasons of emergence and a variable number of seasons following, however, a subpopulation above a threshold age invariably enjoyed reduced mortality. 'Immune escape', a stepwise increase in mortality among the oldest elderly, was observed a number of seasons after both the A(H2N2) and A(H3N2) pandemics. The number of seasons from emergence to escape varied by country. For the latter pandemic, mortality rates in four countries increased for younger age groups but only in the season following that of emergence. Adaptation to both emergent viruses was apparent as a progressive decrease in mortality rates, which, with two exceptions, was seen only in younger age groups. Pandemic attack rate variation with age was estimated to be similar across four pandemics with very different mortality impact. Conclusions In all influenza pandemics of the 20th century, emergent viruses resembled those that had circulated previously within the lifespan of then-living people. Such individuals were relatively immune to the emergent strain, but this immunity waned with mutation of the emergent virus. An immune subpopulation complicates and may invalidate vaccine trials. Pandemic influenza does not 'shift' mortality to younger age groups; rather, the mortality level is reset by the virulence

Screening Women Aged 50-59 for CRC Using Fecal Occult Blood Test Produces Outcomes Similar to Men Undergoing Screening Colonoscopy.

PubMed

Mooers, Harrison M; Holub, Jennifer L; Lieberman, David A

2018-06-13

Average-risk women aged 50-59 years have a lower incidence and mortality of colorectal cancer relative to age-matched men, calling into question the benefit of screening colonoscopy in this age group. We aimed to determine whether FOBT is an effective initial screening test in 50-59-year-old women. We conducted a cross-sectional study using a computerized endoscopic report generator. We identified 320,906 individuals who had average-risk screening colonoscopy and 32,369 who had colonoscopy for positive FOBT. The primary outcome was the positive predictive value (PPV) of FOBT for large polyp(s) greater than 9 mm, as a surrogate for advanced neoplasia. Among patients aged 50-59 years undergoing screening colonoscopy, men were more likely than women to have large polyps (6.3 vs 4.2%, p < 0.0001). Black women undergoing screening colonoscopy had higher rates of large polyps compared to non-Black women. The PPV in FOBT-positive men aged 50-54 (11.5%) and 55-59 (14.4%) was higher than in women aged 50-54 (6.1%) and 55-59 (5.4%). Despite this lower PPV, women aged 50-54 with a positive FOBT had a similar rate of large polyps as 50-54-year-old men undergoing screening colonoscopy (6.1 vs 6.3%, p = 0.626). CRC screening with FOBT identifies 50-59-year-old men and women with a higher risk of large polyps. Since younger women have a lower risk of large polyps than men, screening with FOBT in 50-59-year-old non-Black women could be an effective screening strategy, with outcomes similar to the use of screening colonoscopy in 50-59-year-old men.

Perceiving similarity and comprehending metaphor.

PubMed

Marks, L E; Hammeal, R J; Bornstein, M H

1987-01-01

We conducted a series of 3 experiments to assess the comprehension of 4 types of cross-modal (synesthetic) similarities in nearly 500 3.5-13.5-year-old children and more than 100 adults. We tested both perceptual and verbal (metaphoric) modes. Children of all ages and adults matched pitch to brightness and loudness to brightness, thereby showing that even very young children recognize perceptual similarities between hearing and vision. Children did not consistently recognize similarity between pitch and size until about age 11. This difference in developmental timetables is compatible with the view that pitch-brightness and loudness-brightness similarities are intrinsic characteristics of perception (characteristics based, perhaps, on common sensory codes), whereas pitch-size similarity may be learned (perhaps through association of size with resonance properties). In a parallel verbal task, even 4-year-old children showed at least some capacity to translate meanings metaphorically from one modality to another (e.g., rating "low pitched" as dim and "high pitched" as bright). But not all literal meanings produced metaphoric equivalents in the youngest children (e.g., rating "sunlight" brighter but not louder than "moonlight"). Improvements with age in making metaphoric translations of synesthetic expressions paralleled increasing differentiation of meanings along literal dimensions and increasing capacity to integrate meanings of components in compound expressions. We postulate that perceptual knowledge about objects and events is represented in terms of locations in a multidimensional space; cross-modal similarities imply that the space is also multimodal. Verbal processes later gain access to this graded perceptual knowledge, thus permitting the interpretation of synesthetic metaphors according to the rules of cross-modal perception.

Adult age differences in wrap-up during sentence comprehension: evidence from ex-Gaussian distributional analyses of reading time.

PubMed

Payne, Brennan R; Stine-Morrow, Elizabeth A L

2014-06-01

We report a secondary data analysis investigating age differences in the effects of clause and sentence wrap-up on reading time distributions during sentence comprehension. Residual word-by-word self-paced reading times were fit to the ex-Gaussian distribution to examine age differences in the effects of clause and sentence wrap-up on both the location and shape of participants' reaction time (RT) distributions. The ex-Gaussian distribution showed good fit to the data in both younger and older adults. Sentence wrap-up increased the central tendency, the variability, and the tail of the distribution, and these effects were exaggerated among the old. In contrast, clause wrap-up influenced the tail of the distribution only, and did so differentially for older adults. Effects were confirmed via nonparametric vincentile plots. Individual differences in visual acuity, working memory, speed of processing, and verbal ability were differentially related to ex-Gaussian parameters reflecting wrap-up effects on underlying reading time distributions. These findings argue against simple pause mechanisms to explain end-of-clause and end-of-sentence reading time patterns; rather, the findings are consistent with a cognitively effortful view of wrap-up and suggest that age and individual differences in attentional allocation to semantic integration during reading, as revealed by RT distribution analyses, play an important role in sentence understanding. PsycINFO Database Record (c) 2014 APA, all rights reserved.

HOW THE U.S. PRISON BOOM HAS CHANGED THE AGE DISTRIBUTION OF THE PRISON POPULATION*

PubMed Central

PORTER, LAUREN C.; BUSHWAY, SHAWN D.; TSAO, HUI-SHIEN; SMITH, HERBERT L.

2017-01-01

This article provides a demographic exposition of the changes in the U.S prison population during the period of mass incarceration that began in the late twentieth century. By drawing on data from the Survey of Inmates in State Correctional Facilities (1974–2004) for inmates 17–72 years of age (N = 336), we show that the age distribution shifted upward dramatically: Only 16 percent of the state prison population was 40 years old or older in 1974; by 2004, this percentage had doubled to 33 percent with the median age of prisoners rising from 27 to 34 years old. By using an estimable function approach, we find that the change in the age distribution of the prison population is primarily a cohort effect that is driven by the “enhanced” penal careers of the cohorts who hit young adulthood—the prime age of both crime and incarceration—when substance use was at its peak. Period-specific factors (e.g., proclivity for punishment and incidence of offense) do matter, but they seem to play out more across the life cycles of persons most affected in young adulthood (cohort effects) than across all age groups at one point in time (period effects). PMID:28936228

The gender similarities hypothesis.

PubMed

Hyde, Janet Shibley

2005-09-01

The differences model, which argues that males and females are vastly different psychologically, dominates the popular media. Here, the author advances a very different view, the gender similarities hypothesis, which holds that males and females are similar on most, but not all, psychological variables. Results from a review of 46 meta-analyses support the gender similarities hypothesis. Gender differences can vary substantially in magnitude at different ages and depend on the context in which measurement occurs. Overinflated claims of gender differences carry substantial costs in areas such as the workplace and relationships. Copyright (c) 2005 APA, all rights reserved.

Molecular size and molecular size distribution affecting traditional balsamic vinegar aging.

PubMed

Falcone, Pasquale Massimiliano; Giudici, Paolo

2008-08-27

A first attempt at a semiquantitative study of molecular weight (MW) and molecular weight distribution (MWD) in cooked grape must and traditional balsamic vinegar (TBV) with increasing well-defined age was performed by high-performance liquid size exclusion chromatography (SEC) using dual detection, that is, differential refractive index (DRI) and absorbance (UV-vis) based detectors. With this aim, MW and MWD, including number- and weight-average MW and polydispersity, were determined with respect to a secondary standard and then analyzed. All investigated vinegar samples were recognized as compositionally and structurally heterogeneous blends of copolymers (melanoidins) spreading over a wide range of molecular sizes: the relative MW ranged from 2 to >2000 kDa. The extent of the polymerization reactions was in agreement with the TBV browning kinetics. MWD parameters varied asymptotically toward either upper or lower limits during aging, reflecting a nonequilibrium status of the balance between polymerization and depolymerization reactions in TBV. MWD parameters were proposed as potential aging markers of TBV.

Cobalt Distribution and Speciation: Effect of Aging, Intermittent Submergence, In situ Rice Roots

EPA Science Inventory

The speciation and distribution of cobalt (Co) in soils is poorly understood. This study was conducted using X-ray absorption spectroscopy (XAS) techniques to examine the influence of soluble Co(II) aging, submergence-dried cycling, and the presence of in vivo rice roots on the...

Similarity Measures for Protein Ensembles

PubMed Central

Lindorff-Larsen, Kresten; Ferkinghoff-Borg, Jesper

2009-01-01

Analyses of similarities and changes in protein conformation can provide important information regarding protein function and evolution. Many scores, including the commonly used root mean square deviation, have therefore been developed to quantify the similarities of different protein conformations. However, instead of examining individual conformations it is in many cases more relevant to analyse ensembles of conformations that have been obtained either through experiments or from methods such as molecular dynamics simulations. We here present three approaches that can be used to compare conformational ensembles in the same way as the root mean square deviation is used to compare individual pairs of structures. The methods are based on the estimation of the probability distributions underlying the ensembles and subsequent comparison of these distributions. We first validate the methods using a synthetic example from molecular dynamics simulations. We then apply the algorithms to revisit the problem of ensemble averaging during structure determination of proteins, and find that an ensemble refinement method is able to recover the correct distribution of conformations better than standard single-molecule refinement. PMID:19145244

Apparent Transition in the Human Height Distribution Caused by Age-Dependent Variation during Puberty Period

NASA Astrophysics Data System (ADS)

Iwata, Takaki; Yamazaki, Yoshihiro; Kuninaka, Hiroto

2013-08-01

In this study, we examine the validity of the transition of the human height distribution from the log-normal distribution to the normal distribution during puberty, as suggested in an earlier study [Kuninaka et al.: J. Phys. Soc. Jpn. 78 (2009) 125001]. Our data analysis reveals that, in late puberty, the variation in height decreases as children grow. Thus, the classification of a height dataset by age at this stage leads us to analyze a mixture of distributions with larger means and smaller variations. This mixture distribution has a negative skewness and is consequently closer to the normal distribution than to the log-normal distribution. The opposite case occurs in early puberty and the mixture distribution is positively skewed, which resembles the log-normal distribution rather than the normal distribution. Thus, this scenario mimics the transition during puberty. Additionally, our scenario is realized through a numerical simulation based on a statistical model. The present study does not support the transition suggested by the earlier study.

Applicability of the Hypersonic Similarity Rule to Pressure Distributions which Include the Effects of Rotation for Bodies of Revolution at Zero Angle of Attack

NASA Technical Reports Server (NTRS)

Rossow, Vernon J

1951-01-01

The analysis of Technical Note 2250, 1950, is extended to include the effects of flow rotation. It is found that the theoretical pressure distributions over drive cylinders can be related by the hypersonic similarity rule with sufficient accuracy for most engineering purposes. The error introduced into pressure distributions and drag effective cylinders by ignoring the rotation term in the characteristic equations is investigated.

Competition and Habitat Quality Influence Age and Sex Distribution in Wintering Rusty Blackbirds

PubMed Central

Mettke-Hofmann, Claudia; Hamel, Paul B.; Hofmann, Gerhard; Zenzal Jr., Theodore J.; Pellegrini, Anne; Malpass, Jennifer; Garfinkel, Megan; Schiff, Nathan

2015-01-01

Bird habitat quality is often inferred from species abundance measures during the breeding and non-breeding season and used for conservation management decisions. However, during the non-breeding season age and sex classes often occupy different habitats which suggest a need for more habitat-specific data. Rusty Blackbird (Euphagus carolinus) is a forested wetland specialist wintering in bottomland hardwood forests in the south-eastern U. S. and belongs to the most steeply declining songbirds in the U.S. Little information is available to support priority birds such as the Rusty Blackbird wintering in this threatened habitat. We assessed age and sex distribution and body condition of Rusty Blackbirds among the three major habitats used by this species in the Lower Mississippi Alluvial Valley and also measured food availability. Overall, pecan groves had the highest biomass mainly driven by the amount of nuts. Invertebrate biomass was highest in forests but contributed only a small percentage to overall biomass. Age and sex classes were unevenly distributed among habitats with adult males primarily occupying pecan groves containing the highest nut biomass, females being found in forests which had the lowest nut biomass and young males primarily staying in forest fragments along creeks which had intermediate nut biomass. Males were in better body condition than females and were in slightly better condition in pecan groves. The results suggest that adult males occupy the highest quality habitat and may competitively exclude the other age and sex classes. PMID:25946335

Competition and habitat quality influence age and sex distribution in wintering rusty blackbirds.

PubMed

Mettke-Hofmann, Claudia; Hamel, Paul B; Hofmann, Gerhard; Zenzal, Theodore J; Pellegrini, Anne; Malpass, Jennifer; Garfinkel, Megan; Schiff, Nathan; Greenberg, Russell

2015-01-01

Bird habitat quality is often inferred from species abundance measures during the breeding and non-breeding season and used for conservation management decisions. However, during the non-breeding season age and sex classes often occupy different habitats which suggest a need for more habitat-specific data. Rusty Blackbird (Euphagus carolinus) is a forested wetland specialist wintering in bottomland hardwood forests in the south-eastern U. S. and belongs to the most steeply declining songbirds in the U.S. Little information is available to support priority birds such as the Rusty Blackbird wintering in this threatened habitat. We assessed age and sex distribution and body condition of Rusty Blackbirds among the three major habitats used by this species in the Lower Mississippi Alluvial Valley and also measured food availability. Overall, pecan groves had the highest biomass mainly driven by the amount of nuts. Invertebrate biomass was highest in forests but contributed only a small percentage to overall biomass. Age and sex classes were unevenly distributed among habitats with adult males primarily occupying pecan groves containing the highest nut biomass, females being found in forests which had the lowest nut biomass and young males primarily staying in forest fragments along creeks which had intermediate nut biomass. Males were in better body condition than females and were in slightly better condition in pecan groves. The results suggest that adult males occupy the highest quality habitat and may competitively exclude the other age and sex classes.

Sex, race, and age distributions of mean aortic wall thickness in a multiethnic population-based sample.

PubMed

Rosero, Eric B; Peshock, Ronald M; Khera, Amit; Clagett, Patrick; Lo, Hao; Timaran, Carlos H

2011-04-01

Reference values and age-related changes of the wall thickness of the abdominal aorta have not been described in the general population. We characterized age-, race-, and gender-specific distributions, and yearly rates of change of mean aortic wall thickness (MAWT), and associations between MAWT and cardiovascular risk factors in a multi-ethnic population-based probability sample. Magnetic resonance imaging measurements of MAWT were performed on 2466 free-living white, black, and Hispanic adult subjects. MAWT race/ethnicity- and gender-specific percentile values across age were estimated using regression analyses. MAWT was greater in men than in women and increased linearly with age in all the groups and across all the percentiles. Hispanic women had the thinnest and black men the thickest aortas. Black men had the highest and white women the lowest age-related MAWT increase. Age, gender, ethnicity, smoking status, systolic blood pressure, low-density lipoprotein-cholesterol levels, high-density lipoprotein-cholesterol levels, and fasting glucose levels were independent predictors of MAWT. Age, gender, and racial/ethnic differences in MAWT distributions exist in the general population. Such differences should be considered in future investigations assessing aortic atherosclerosis and the effects of anti-atherosclerotic therapies. Published by Mosby, Inc.

Age and secular distributions of virus-proven influenza patients in successive epidemics 1961-1976 in Cirencester: epidemiological significance discussed.

PubMed Central

Hope-Simpson, R. E.

1984-01-01

A general practice population of around 3900, under continuous clinical and laboratory surveillance, experienced 20 outbreaks of influenza between March 1960 and March 1976. Four epidemics were caused by subtype H2N2 type A viruses, seven by subtype H3N2 type A viruses and nine outbreaks by type B viruses. The age of every person proved virologically to have influenza is related to the age structure of the community and to the phase of the epidemic in which the virus-positive specimens were collected. Children 0-15 years old suffered a higher incidence rate than adults 16-90+. Pre-school children 0-4 suffered the highest rate of infection by viruses of both influenza A subtypes, whereas older schoolchildren 10-15 suffered the highest rate of type B infections. Despite these high incidence rates neither pre-school nor schoolchildren appear to have been the major disseminators of any of these influenza viruses in the community. Adults of all ages suffered a high rate of infection even into extreme old age, and the indiscriminate age distribution among adults was sustained in the successive epidemics. Such age-patterns are not those caused by a highly infectious immunizing virus surviving by means of direct transmissions from the sick, whose prompt development of the disease continues endless chains of transmissions. An alternative epidemic mechanism--whereby the virus does not spread from the sick but becomes latent in them, reactivating seasonally so that they later infect their companions--would produce age patterns similar to those recorded here for influenza patients. The suggested mechanism is illustrated by a simple conceptual model and the influenzal age patterns are discussed in relation to the recycling of influenza A subtypes. PMID:6736641

Do predators influence the distribution of age-0 kokanee in a Colorado Reservoir?

USGS Publications Warehouse

Hardiman, J.M.; Johnson, B.M.; Martinez, P.J.

2004-01-01

Seasonal changes in reservoir conditions such as productivity, light, and temperature create spatiotemporal variation in habitat that may segregate or aggregate predators and prey, producing implications for the distribution, growth, and survival of fishes. We used hydroacoustics to document the diel vertical distribution of age-0 kokanee Oncorhynchus nerka relative to environmental gradients at Blue Mesa Reservoir, Colorado, during May-August of 2002. Temperature, light, and zooplankton density profiles were examined relative to foraging conditions for kokanee and their primary predator, lake trout Salvelinus namaycush. Age-0 kokanee displayed large diel vertical migrations in May despite the lack of an energetic advantage before reservoir stratification. Age-0 kokanee minimized near-surface foraging at this time, perhaps to avoid predation by visual predators, such as lake trout, in the well-lit surface waters. Strong reservoir stratification in midsummer appeared to provide a thermal refuge from lake trout that the kokanee exploited. By August vertical migrations were shallow and most kokanee remained in the epilimnion throughout the day. Although the energetic implications of the late-summer strategy are unclear, it appears that kokanee were responding to changes in their predator environment. A robust model for kokanee diel vertical migration across a range of systems should include a predator avoidance component.

Injury-related hospital admissions of military dependents compared with similarly aged nonmilitary insured infants, children, and adolescents.

PubMed

Pressley, Joyce C; Dawson, Patrick; Carpenter, Dustin J

2012-10-01

Military deployment of one or both parents is associated with declines in school performance, behavioral difficulties, and increases in reported mental health conditions, but less is known regarding injury risks in pediatric military dependents. Kid Health Care Cost and Utilization Project 2006 (KID) was used to identify military dependents aged 0.1 year to 17 years through expected insurance payer being CHAMPUS, Tricare, or CHAMPVA (n = 12,310) and similarly aged privately insured nonmilitary in CHAMPUS, Tricare, or CHAMPVA states (n = 730,065). Mental health diagnoses per 1,000 hospitalizations and mechanisms of injury per 1,000 injury-related hospitalizations are reported. Unweighted univariate analyses used Fisher's exact, χ(2), and analysis of variance tests for significance. Odds ratios are age and sex adjusted with 95% confidence intervals. Injury-related admissions were higher in military than in nonmilitary dependents (15.5% vs. 13.2%, p < 0.0001). Age- and sex-adjusted motor vehicle occupant and pedestrian injuries were significantly lower in all-age military dependents but not in age-stratified categories. Very young military dependents had higher all-cause injury admissions (p < 0.0001), drowning/near drowning (p < 0.0001), and intracranial injury (p < 0.0001) and showed a tendency toward higher suffocation (p = 0.055) and crushing injury (p = 0.065). Military adolescents and teenagers had higher suicide/suicide attempts (p = 0.0001) and poisonings from medicinal substances (p = 0.0001). Mental health diagnoses were significantly higher in every age category of military dependents. All-cause in-hospital mortality tended to be greater in military than in nonmilitary dependents (p = 0.052). This study suggests that military dependents are a vulnerable population with special needs and provides clues to areas where injury prevention professionals might begin to address their needs. Prognostic/epidemiologic study, level II.

Mortality Associated with Severe Sepsis Among Age-Similar Women with and without Pregnancy-Associated Hospitalization in Texas: A Population-Based Study.

PubMed

Oud, Lavi

2016-06-10

BACKGROUND The reported mortality among women with pregnancy-associated severe sepsis (PASS) has been considerably lower than among severely septic patients in the general population, with the difference being attributed to the younger age and lack of chronic illness among the women with PASS. However, no comparative studies were reported to date between patients with PASS and age-similar women with severe sepsis not associated with pregnancy (NPSS). MATERIAL AND METHODS We used the Texas Inpatient Public Use Data File to compare the crude and adjusted hospital mortality between women with severe sepsis, aged 20-34 years, with and without pregnancy-associated hospitalizations during 2001-2010, following exclusion of those with reported chronic comorbidities, as well as alcohol and drug abuse. RESULTS Crude hospital mortality among PASS vs. NPSS hospitalizations was lower for the whole cohort (6.7% vs. 14.1% [p<0.0001]) and those with ≥3 organ failures (17.6% vs. 33.2% [p=0.0100]). Adjusted PASS mortality (odds ratio [95% CI]) was 0.57 (0.38-0.86) [p=0.0070]. CONCLUSIONS Hospital mortality was unexpectedly markedly and consistently lower among women with severe sepsis associated with pregnancy, as compared with contemporaneous, age-similar women with severe sepsis not associated with pregnancy, without reported chronic comorbidities. Further studies are warranted to examine the sources of the observed differences and to corroborate our findings.

Evaluating visibility of age spot and freckle based on simulated spectral reflectance distribution and facial color image

NASA Astrophysics Data System (ADS)

Hirose, Misa; Toyota, Saori; Tsumura, Norimichi

2018-02-01

In this research, we evaluate the visibility of age spot and freckle with changing the blood volume based on simulated spectral reflectance distribution and the actual facial color images, and compare these results. First, we generate three types of spatial distribution of age spot and freckle in patch-like images based on the simulated spectral reflectance. The spectral reflectance is simulated using Monte Carlo simulation of light transport in multi-layered tissue. Next, we reconstruct the facial color image with changing the blood volume. We acquire the concentration distribution of melanin, hemoglobin and shading components by applying the independent component analysis on a facial color image. We reproduce images using the obtained melanin and shading concentration and the changed hemoglobin concentration. Finally, we evaluate the visibility of pigmentations using simulated spectral reflectance distribution and facial color images. In the result of simulated spectral reflectance distribution, we found that the visibility became lower as the blood volume increases. However, we can see that a specific blood volume reduces the visibility of the actual pigmentations from the result of the facial color images.

A method to estimate stellar ages from kinematical data

NASA Astrophysics Data System (ADS)

Almeida-Fernandes, F.; Rocha-Pinto, H. J.

2018-05-01

We present a method to build a probability density function (PDF) for the age of a star based on its peculiar velocities U, V, and W and its orbital eccentricity. The sample used in this work comes from the Geneva-Copenhagen Survey (GCS) that contains the spatial velocities, orbital eccentricities, and isochronal ages for about 14 000 stars. Using the GCS stars, we fitted the parameters that describe the relations between the distributions of kinematical properties and age. This parametrization allows us to obtain an age probability from the kinematical data. From this age PDF, we estimate an individual average age for the star using the most likely age and the expected age. We have obtained the stellar age PDF for the age of 9102 stars from the GCS and have shown that the distribution of individual ages derived from our method is in good agreement with the distribution of isochronal ages. We also observe a decline in the mean metallicity with our ages for stars younger than 7 Gyr, similar to the one observed for isochronal ages. This method can be useful for the estimation of rough stellar ages for those stars that fall in areas of the Hertzsprung-Russell diagram where isochrones are tightly crowded. As an example of this method, we estimate the age of Trappist-1, which is a M8V star, obtaining the age of t(UVW) = 12.50(+0.29 - 6.23) Gyr.

Age-related similarities and differences in first impressions of trustworthiness.

PubMed

Bailey, Phoebe E; Szczap, Paulina; McLennan, Skye N; Slessor, Gillian; Ruffman, Ted; Rendell, Peter G

2016-08-01

Trust is a particularly under-studied aspect of social relationships in older age. In the current study, young (n = 35) and older adults (n = 35) completed a series of one-shot social economic trust games in which they invested real money with trustees. There were potential gains with each investment and also a risk of losing everything if the trustee was untrustworthy. The reputation and facial appearance of each trustee were manipulated to make them appear more or less trustworthy. Results revealed that young and older adults invest more money with trustees whose facial appearance and reputation indicate that they are trustworthy rather than untrustworthy. However, older adults were more likely than young to invest with trustees who had a reputation for being untrustworthy. We discuss whether age-related differences in responding to negative information may account for an age-related increase in trust, particularly when trusting someone with a reputation for being uncooperative.

Perspectives on the age and distribution of large wood in riparian carbon pools

Treesearch

Richard P. Guyette; William G. Cole; Daniel C. Dey; Rose-Marie Muzkia

2002-01-01

Most knowledge of carbon budgets is derived from the productivity and sequestration of carbon in terrestrial and marine ecosystems. Less is known of carbon stored in riparian areas associated with lakes and rivers. Case studies of the age distribution of carbon in aquatic large wood (C1w) from two different landscapes with different drainage...

Mortality Associated with Severe Sepsis Among Age-Similar Women with and without Pregnancy-Associated Hospitalization in Texas: A Population-Based Study

PubMed Central

Oud, Lavi

2016-01-01

Background The reported mortality among women with pregnancy-associated severe sepsis (PASS) has been considerably lower than among severely septic patients in the general population, with the difference being attributed to the younger age and lack of chronic illness among the women with PASS. However, no comparative studies were reported to date between patients with PASS and age-similar women with severe sepsis not associated with pregnancy (NPSS). Material/Methods We used the Texas Inpatient Public Use Data File to compare the crude and adjusted hospital mortality between women with severe sepsis, aged 20–34 years, with and without pregnancy-associated hospitalizations during 2001–2010, following exclusion of those with reported chronic comorbidities, as well as alcohol and drug abuse. Results Crude hospital mortality among PASS vs. NPSS hospitalizations was lower for the whole cohort (6.7% vs. 14.1% [p<0.0001]) and those with ≥3 organ failures (17.6% vs. 33.2% [p=0.0100]). Adjusted PASS mortality (odds ratio [95% CI]) was 0.57 (0.38–0.86) [p=0.0070]. Conclusions Hospital mortality was unexpectedly markedly and consistently lower among women with severe sepsis associated with pregnancy, as compared with contemporaneous, age-similar women with severe sepsis not associated with pregnancy, without reported chronic comorbidities. Further studies are warranted to examine the sources of the observed differences and to corroborate our findings. PMID:27286326

Segmenting Bone Parts for Bone Age Assessment using Point Distribution Model and Contour Modelling

NASA Astrophysics Data System (ADS)

Kaur, Amandeep; Singh Mann, Kulwinder, Dr.

2018-01-01

Bone age assessment (BAA) is a task performed on radiographs by the pediatricians in hospitals to predict the final adult height, to diagnose growth disorders by monitoring skeletal development. For building an automatic bone age assessment system the step in routine is to do image pre-processing of the bone X-rays so that features row can be constructed. In this research paper, an enhanced point distribution algorithm using contours has been implemented for segmenting bone parts as per well-established procedure of bone age assessment that would be helpful in building feature row and later on; it would be helpful in construction of automatic bone age assessment system. Implementation of the segmentation algorithm shows high degree of accuracy in terms of recall and precision in segmenting bone parts from left hand X-Rays.

The modulation of the motor resonance triggered by reach-to-grasp movements: No role of human physical similarity as conveyed by age.

PubMed

Marino, Barbara F M; Ricciardelli, Paola

2017-07-01

The activation of the mirror-neuron circuit during the observation of motor acts is thought to be the basis of human capacity to read the intentions behind the behavior of others. Growing empirical evidence shows a different activation of the mirror-neuron resonance mechanism depending on how much the observer and the observed agent share their motor repertoires. Here, the possible modulatory effect of physical similarity between the observer and the agent was investigated in three studies. We used a visuo-motor priming task in which participants were asked to categorize manipulable and non-manipulable objects into natural or man-made kinds after having watched precision and power reach-to-grasp movements. Physical similarity was manipulated by presenting reach-to-grasp movements performed by the hands of actors of three different age ranges that are adults of the same age as the participants, children, and elderly. Faster responses were observed in trials where power grip movements were performed by the adults and precision grip movements were performed by the elderly (Main Study). This finding is not in keeping with the idea that physical similarity shapes the mirror-neuron resonance. Instead, it suggests an effect of the kinematic organization of the reach-to-grasp movements, which systematically changed with the actor age as revealed by a kinematic analysis. The differential effect played by adult and elderly actor primes was lost when static grasping hands (Control Study 1) and reach-to-grasp movements with uniform kinematic profiles (Control Study 2) were used. Therefore, we found preliminary evidence that mirror-neuron resonance is not shaped by physical similarity but by the kinematics of the observed action. This finding is novel as it suggests that human ability to read the intentions behind the behavior of others may benefit from a mere visual processing of spatiotemporal patterns.

Trend in unequal geographical distribution of doctors by age and sex in Japan from 2004 to 2014.

PubMed

Morita, T; Tanimoto, T; Morita, M; Tsubokura, M; Kami, M

2018-06-01

In Japan, the proportion of female doctors and elderly doctors is increasing as in other countries. We investigated the relationship between doctors' demographic changes and their geographical distribution. A national database study. We assessed trends in unequal geographical distribution of the number of doctors by sex and age from 2004 to 2014 in Japan. The Gini coefficient values for the number of female doctors (0.18) were larger than those for male doctors across all generations (0.13-0.14). The Gini coefficient values for the number of elderly doctors aged 60 years and older (male: 0.12, female: 0.18-0.23) were larger than those for majority age groups aged 40-59 years (male: 0.10, female: 0.16-0.17). The persisting geographical maldistribution of doctors may be associated with demographic changes, such as increase in the number of female doctors. Copyright © 2018 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Vere-Jones' self-similar branching model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saichev, A.; Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90095; Sornette, D.

2005-11-01

Motivated by its potential application to earthquake statistics as well as for its intrinsic interest in the theory of branching processes, we study the exactly self-similar branching process introduced recently by Vere-Jones. This model extends the ETAS class of conditional self-excited branching point-processes of triggered seismicity by removing the problematic need for a minimum (as well as maximum) earthquake size. To make the theory convergent without the need for the usual ultraviolet and infrared cutoffs, the distribution of magnitudes m{sup '} of daughters of first-generation of a mother of magnitude m has two branches m{sup '}m with exponent {beta}+d, where {beta} and d are two positive parameters. We investigate the condition and nature of the subcritical, critical, and supercritical regime in this and in an extended version interpolating smoothly between several models. We predict that the distribution of magnitudes of events triggered by a mother of magnitude m over all generations has also two branches m{sup '}m with exponent {beta}+h, with h=d{radical}(1-s), where s is the fraction of triggered events. This corresponds to a renormalization of the exponent d into h by the hierarchy of successive generations of triggered events. For a significant part of the parameter space, the distribution of magnitudes over a full catalog summed over an average steady flow of spontaneous sources (immigrants) reproduces the distribution of the spontaneous sources with a single branch and is blind to the exponents {beta},d of the distribution of triggered events. Since the distribution of earthquake magnitudes is usually obtained with catalogs including many sequences, we conclude that the two branches of the distribution of aftershocks are not directly observable and the model is compatible with real seismic catalogs. In summary, the exactly self-similar Vere-Jones model provides an

Another stage of development: Biological degeneracy and the study of bodily ageing.

PubMed

Mason, Paul H; Maleszka, Ryszard; Dominguez D, Juan F

2017-04-01

Ageing is a poorly understood process of human development mired by a scientific approach that struggles to piece together distributed variable factors involved in ongoing transformations of living systems. Reconfiguring existing research paradigms, we review the concept of 'degeneracy', which has divergent popular and technical definitions. The technical meaning of degeneracy refers to the structural diversity underlying functional plasticity. Degeneracy is a distributed system property that can be observed within individual brains or across different brains. For example, dementias with similar behavioural anomalies can result from a diverse range of cellular "faults", which is an example of degeneracy because the symptoms are similar in spite of different underlying mechanisms. Degeneracy is a valuable epistemological tool that can transformatively enhance scientific models of bodily ageing. We propose that movement science is one of the first areas that can productively integrate degeneracy into models of bodily ageing. We also propose model organisms such as eusocial honey bees in which degeneracy can be studied at the molecular and cellular level. Developing a vocabulary for thinking about how distributed variable factors are interlinked is important if we are to understand bodily ageing not as a single entity, but as the heterogeneous construction of changing biological, social, and environmental processes. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Heart Rate and Blood Pressure Centile Curves and Distributions by Age of Hospitalized Critically Ill Children.

PubMed

Eytan, Danny; Goodwin, Andrew J; Greer, Robert; Guerguerian, Anne-Marie; Laussen, Peter C

2017-01-01

Heart rate (HR) and blood pressure (BP) form the basis for monitoring the physiological state of patients. Although norms have been published for healthy and hospitalized children, little is known about their distributions in critically ill children. The objective of this study was to report the distributions of these basic physiological variables in hospitalized critically ill children. Continuous data from bedside monitors were collected and stored at 5-s intervals from 3,677 subjects aged 0-18 years admitted over a period of 30 months to the pediatric and cardiac intensive care units at a large quaternary children's hospital. Approximately 1.13 billion values served to estimate age-specific distributions for these two basic physiological variables: HR and intra-arterial BP. Centile curves were derived from the sample distributions and compared to common reference ranges. Properties such as kurtosis and skewness of these distributions are described. In comparison to previously published reference ranges, we show that children in these settings exhibit markedly higher HRs than their healthy counterparts or children hospitalized on in-patient wards. We also compared commonly used published estimates of hypotension in children (e.g., the PALS guidelines) to the values we derived from critically ill children. This is a first study reporting the distributions of basic physiological variables in children in the pediatric intensive care settings, and the percentiles derived may serve as useful references for bedside clinicians and clinical trials.

The urinary microbiome in women with mixed urinary incontinence compared to similarly aged controls.

PubMed

Komesu, Yuko M; Richter, Holly E; Carper, Benjamin; Dinwiddie, Darrell L; Lukacz, Emily S; Siddiqui, Nazema Y; Sung, Vivian W; Zyczynski, Halina M; Ridgeway, Beri; Rogers, Rebecca G; Arya, Lily A; Mazloomdoost, Donna; Gantz, Marie G

2018-06-16

Previous studies have suggested that women with urinary incontinence have an altered urinary microbiome. We hypothesized that the microbiome in women with mixed urinary incontinence (MUI) differed from controls and tested this hypothesis using bacterial gene sequencing techniques. This multicenter study compared the urinary microbiome in women with MUI and similarly aged controls. Catheterized urine samples were obtained; v4-6 regions of the 16S rRNA gene were sequenced to identify bacteria. Bacterial predominance (> 50% of an individual's genera) was compared between MUI and controls. Bacterial sequences were categorized into "community types" using Dirichlet multinomial mixture (DMM) methods. Generalized linear mixed models predicted MUI/control status based on clinical characteristics and community type. Post-hoc analyses were performed in women < 51 and ≥ 51 years. Sample size estimates required 200 samples to detect a 20% difference in Lactobacillus predominance with P < 0.05. Of 212 samples, 97.6% were analyzed (123 MUI/84 controls, mean age 53 ± 11 years). Overall Lactobacillus predominance did not differ between MUI and controls (45/123 = 36.6% vs. 36/84 = 42.9%, P = 0.36). DMM analyses revealed six community types; communities differed by age (P = 0.001). A High-Lactobacillus (89.2% Lactobacillus) community had a greater proportion of controls (19/84 = 22.6%, MUI 11/123 = 8.9%). Overall, bacterial community types did not differ in MUI and controls. However, post-hoc analysis of women < 51 years found that bacterial community types distinguished MUI from controls (P = 0.041); Moderate-Lactobacillus (aOR 7.78, CI 1.85-32.62) and Mixed (aOR 7.10, CI 1.32-38.10) community types were associated with MUI. Community types did not differentiate MUI and controls in women ≥ 51 years (P = 0.94). Women with MUI and controls did not differ in overall Lactobacillus predominance. In younger women, urinary bacterial

Aging in complex interdependency networks.

PubMed

Vural, Dervis C; Morrison, Greg; Mahadevan, L

2014-02-01

Although species longevity is subject to a diverse range of evolutionary forces, the mortality curves of a wide variety of organisms are rather similar. Here we argue that qualitative and quantitative features of aging can be reproduced by a simple model based on the interdependence of fault-prone agents on one other. In addition to fitting our theory to the empiric mortality curves of six very different organisms, we establish the dependence of lifetime and aging rate on initial conditions, damage and repair rate, and system size. We compare the size distributions of disease and death and see that they have qualitatively different properties. We show that aging patterns are independent of the details of interdependence network structure, which suggests that aging is a many-body effect, and that the qualitative and quantitative features of aging are not sensitively dependent on the details of dependency structure or its formation.

Regional Evaluation of Groundwater Age Distributions Using Lumped Parameter Models with Large, Sparse Datasets: Example from the Central Valley, California, USA

NASA Astrophysics Data System (ADS)

Jurgens, B. C.; Bohlke, J. K.; Voss, S.; Fram, M. S.; Esser, B.

2015-12-01

Tracer-based, lumped parameter models (LPMs) are an appealing way to estimate the distribution of age for groundwater because the cost of sampling wells is often less than building numerical groundwater flow models sufficiently complex to provide groundwater age distributions. In practice, however, tracer datasets are often incomplete because of anthropogenic or terrigenic contamination of tracers, or analytical limitations. While age interpretations using such datsets can have large uncertainties, it may still be possible to identify key parts of the age distribution if LPMs are carefully chosen to match hydrogeologic conceptualization and the degree of age mixing is reasonably estimated. We developed a systematic approach for evaluating groundwater age distributions using LPMs with a large but incomplete set of tracer data (3H, 3Hetrit, 14C, and CFCs) from 535 wells, mostly used for public supply, in the Central Valley, California, USA that were sampled by the USGS for the California State Water Resources Control Board Groundwater Ambient Monitoring and Assessment or the USGS National Water Quality Assessment Programs. In addition to mean ages, LPMs gave estimates of unsaturated zone travel times, recharge rates for pre- and post-development groundwater, the degree of age mixing in wells, proportion of young water (<60 yrs), and the depth of the boundary between post-development and predevelopment groundwater throughout the Central Valley. Age interpretations were evaluated by comparing past nitrate trends with LPM predicted trends, and whether the presence or absence of anthropogenic organic compounds was consistent with model results. This study illustrates a practical approach for assessing groundwater age information at a large scale to reveal important characteristics about the age structure of a major aquifer, and of the water supplies being derived from it.

Lipid-laden cells differentially distributed in the aging brain are functionally active and correspond to distinct phenotypes.

PubMed

Shimabukuro, Marilia Kimie; Langhi, Larissa Gutman Paranhos; Cordeiro, Ingrid; Brito, José M; Batista, Claudia Maria de Castro; Mattson, Mark P; Mello Coelho, Valeria de

2016-03-31

We characterized cerebral Oil Red O-positive lipid-laden cells (LLC) of aging mice evaluating their distribution, morphology, density, functional activities and inflammatory phenotype. We identified LLC in meningeal, cortical and neurogenic brain regions. The density of cerebral LLC increased with age. LLC presenting small lipid droplets were visualized adjacent to blood vessels or deeper in the brain cortical and striatal parenchyma of aging mice. LLC with larger droplets were asymmetrically distributed in the cerebral ventricle walls, mainly located in the lateral wall. We also found that LLC in the subventricular region co-expressed beclin-1 or LC3, markers for autophagosome or autophagolysosome formation, and perilipin (PLIN), a lipid droplet-associated protein, suggesting lipophagic activity. Some cerebral LLC exhibited β galactosidase activity indicating a senescence phenotype. Moreover, we detected production of the pro-inflammatory cytokine TNF-α in cortical PLIN(+) LLC. Some cortical NeuN(+) neurons, GFAP(+) glia limitans astrocytes, Iba-1(+) microglia and S100β(+) ependymal cells expressed PLIN in the aging brain. Our findings suggest that cerebral LLC exhibit distinct cellular phenotypes and may participate in the age-associated neuroinflammatory processes.

Lipid-laden cells differentially distributed in the aging brain are functionally active and correspond to distinct phenotypes

PubMed Central

Shimabukuro, Marilia Kimie; Langhi, Larissa Gutman Paranhos; Cordeiro, Ingrid; Brito, José M.; Batista, Claudia Maria de Castro; Mattson, Mark P.; de Mello Coelho, Valeria

2016-01-01

We characterized cerebral Oil Red O-positive lipid-laden cells (LLC) of aging mice evaluating their distribution, morphology, density, functional activities and inflammatory phenotype. We identified LLC in meningeal, cortical and neurogenic brain regions. The density of cerebral LLC increased with age. LLC presenting small lipid droplets were visualized adjacent to blood vessels or deeper in the brain cortical and striatal parenchyma of aging mice. LLC with larger droplets were asymmetrically distributed in the cerebral ventricle walls, mainly located in the lateral wall. We also found that LLC in the subventricular region co-expressed beclin-1 or LC3, markers for autophagosome or autophagolysosome formation, and perilipin (PLIN), a lipid droplet-associated protein, suggesting lipophagic activity. Some cerebral LLC exhibited β galactosidase activity indicating a senescence phenotype. Moreover, we detected production of the pro-inflammatory cytokine TNF-α in cortical PLIN+ LLC. Some cortical NeuN+ neurons, GFAP+ glia limitans astrocytes, Iba-1+ microglia and S100β+ ependymal cells expressed PLIN in the aging brain. Our findings suggest that cerebral LLC exhibit distinct cellular phenotypes and may participate in the age-associated neuroinflammatory processes. PMID:27029648

Hepatic drug acetylation and oxidation: effects of aging in man.

PubMed Central

Farah, F; Taylor, W; Rawlins, M D; James, O

1977-01-01

The half lives of acetanilide and isoniazid ("model" substrates for oxidation and acetylation respectively) were measured in populations of young (aged 20-35 years) and elderly (aged over 65 years) people. Whereas acetanilide half lives were significantly longer in the elderly, isoniazid half lives were distributed similarly in both populations. The results suggest that liver function does not decline uniformly with age and that heterozygotes for acetylation do not possess survival advantages during their middle years of life. PMID:871823

Deep-sea scleractinian coral age and depth distributions in the northwest Atlantic for the last 225,000 years

USGS Publications Warehouse

Robinson, L.F.; Adkins, J.F.; Scheirer, D.S.; Fernandez, D.P.; Gagnon, A.; Waller, R.G.

2007-01-01

Deep-sea corals have grown for over 200,000 yrs on the New England Seamounts in the northwest Atlantic, and this paper describes their distribution both with respect to depth and time. Many thousands of fossil scleractinian corals were collected on a series of cruises from 2003-2005; by contrast, live ones were scarce. On these seamounts, the depth distribution of fossil Desmophyllum dianthus (Esper, 1794) is markedly different to that of the colonial scleractinian corals, extending 750 m deeper in the water column to a distinct cut-off at 2500 m. This cut-off is likely to be controlled by the maximum depth of a notch-shaped feature in the seamount morphology. The ages of D. dianthus corals as determined by U-series measurements range from modern to older than 200,000 yrs. The age distribution is not constant over time, and most corals have ages from the last glacial period. Within the glacial period, increases in coral population density at Muir and Manning Seamounts coincided with times at which large-scale ocean circulation changes have been documented in the deep North Atlantic. Ocean circulation changes have an effect on coral distributions, but the cause of the link is not known. ?? 2007 Rosenstiel School of Marine and Atmospheric Science of the University of Miami.

Optimizing the sequence of diameter distributions and selection harvests for uneven-aged stand management

Treesearch

Robert G. Haight; J. Douglas Brodie; Darius M. Adams

1985-01-01

The determination of an optimal sequence of diameter distributions and selection harvests for uneven-aged stand management is formulated as a discrete-time optimal-control problem with bounded control variables and free-terminal point. An efficient programming technique utilizing gradients provides solutions that are stable and interpretable on the basis of economic...

I owe you: age-related similarities and differences in associative memory for gains and losses.

PubMed

Castel, Alan D; Friedman, Michael C; McGillivray, Shannon; Flores, Cynthia C; Murayama, Kou; Kerr, Tyson; Drolet, Aimee

2016-09-01

Older adults often experience associative memory impairments but can sometimes remember important information. The current experiments investigate potential age-related similarities and differences associate memory for gains and losses. Younger and older participants were presented with faces and associated dollar amounts, which indicated how much money the person "owed" the participant, and were later given a cued recall test for the dollar amount. Experiment 1 examined face-dollar amount pairs while Experiment 2 included negative dollar amounts to examine both gains and losses. While younger adults recalled more information relative to older adults, both groups were more accurate in recalling the correct value associated with high-value faces compared to lower-value faces and remembered gist-information about the values. However, negative values (losses) did not have a strong impact on recall among older adults versus younger adults, illustrating important associative memory differences between younger and older adults.

I Owe You: Age-Related Similarities and Differences in Associative Memory for Gains and Losses

PubMed Central

Castel, Alan D.; Friedman, Michael C.; McGillivray, Shannon; Flores, Cynthia C.; Murayama, Kou; Kerr, Tyson; Drolet, Aimee

2016-01-01

Older adults often experience associative memory impairments but can sometimes remember important information. The current experiments investigate potential age-related similarities and differences associate memory for gains and losses. Younger and older participants were presented with faces and associated dollar amounts, which indicated how much money the person “owed” the participant, and were later given a cued recall test for the dollar amount. Experiment 1 examined face-dollar amount pairs while Experiment 2 included negative dollar amounts to examine both gains and losses. While younger adults recalled more information relative to older adults, both groups were more accurate in recalling the correct value associated with high value faces compared to lower value faces and remembered gist-information about the values. However, negative values (losses) did not have a strong impact on recall among older adults versus younger adults, illustrating important associative memory differences between younger and older adults. PMID:26847137

Plasma steroids, body composition, and fat distribution: effects of age, sex, and exercise training.

PubMed

He, Zihong; Rankinen, Tuomo; Leon, Arthur S; Skinner, James S; Tchernof, André; Bouchard, Claude

2018-03-05

Plasma steroid hormone levels vary between men and women, but their associations with BMI and adiposity are controversial. Furthermore, little is known about the role of exercise programs on the relationship between steroid hormones and adiposity. This report evaluates these relationships for plasma levels of adrenal, gonadal, and conjugated steroids with body composition and fat distribution in sedentary men and women, aged 17-65 years, and their responses to an exercise program. In the sedentary state, 270 men (29% Blacks) and 304 women (34% Blacks) from the HERITAGE Family Study were available. Among them, 242 men and 238 women completed a 20-week fully standardized exercise program. Fourteen steroid hormones and SHBG concentrations were assayed in a fasted state and were compared for their associations with adiposity in men and women and in response to the exercise program. Covariates adjusted for in partial correlation analysis were age, ancestry, menopause status (women), and oral contraceptives/hormone replacement treatment status (women) at baseline, as well as baseline value of the trait for the training response. Differences among normal weight, overweight, and obese subjects were also considered. Statistical significance was set at P < 0.0001. Baseline levels of dihydrotesterone (DHT), 17 hydroxy progesterone (OHPROG), sex hormone-binding globulin (SHBG), and testosterone (TESTO) were negatively associated with fat mass and abdominal fat (P < 0.0001) in men and for SHBG in women (P < 0.0001). TESTO was not correlated with fat-free mass in men or women, but was significantly associated with % fat-free mass in men. No association was detected between baseline steroid hormone levels and changes in adiposity traits in response to 20 weeks of exercise. In men, low DHT, OHPROG, SHBG, and TESTO were associated with higher adiposity and abdominal and visceral fat. A similar adiposity profile was observed in women with low SHBG.

Similarity of female central (hypogonadotropic) hypogonadism and postmenopause.

PubMed

Ilovayskaya, I; Zektser, V; Lazebnik, L

2017-08-01

Central (hypogonadotropic) hypogonadism in women could be a cause of persistent amenorrhea and hypoestrogenemia as observed in postmenopause. This study aimed to compare the clinical, hormonal and biochemical features in women with non-physiological (central hypogonadism) and physiological (postmenopause) hypoestrogenemia. A total of 161 young women, median age 24.9 years (interquartile range (IQR) 21.2; 30.5) with central hypogonadism (with isolated hypogonadotropic hypogonadism, n = 76, and with hypopituitarism, n = 85), 53 healthy young women, median age 23.9 years (IQR 23.1; 28.0) and 50 healthy postmenopausal women, median age 56.0 years (IQR 53.1; 58.5), were examined. Psychoemotional, neurovegetative and urogenital symptoms, sex steroid levels, parameters of lipid and mineral metabolism were evaluated. In young women with central hypogonadism, the frequencies of psychoemotional, neurovegetative and urogenital complaints differed significantly from those in healthy young women and were similar to those in postmenopausal women. Concentrations of estradiol, testosterone, dehydroepiandrosterone sulfate, parameters of lipid and mineral metabolism as well as quality of life in women with central hypogonadism were not typical of healthy young women but were similar to those of postmenopausal women of middle/old age. Despite the young age of women with central hypogonadism, clinical, hormonal and biochemical abnormalities were similar in many aspects to those in postmenopausal women at middle/old age. These revealed features could be considered as signs of premature aging in young amenorrheic women with low gonadotropin levels.

Ages, distributions, and origins of upland coastal dune sheets in Oregon, USA

USGS Publications Warehouse

Peterson, C.D.; Stock, E.; Price, D.M.; Hart, R.; Reckendorf, F.; Erlandson, J.M.; Hostetler, S.W.

2007-01-01

A total of ten upland dune sheets, totaling 245??km in combined length, have been investigated for their origin(s) along the Oregon coast (500??km in length). The ages of dune emplacement range from 0.1 to 103??ka based on radiocarbon (36 samples) and luminescence (46 samples) dating techniques. The majority of the emplacement dates fall into two periods of late-Pleistocene age (11-103??ka) and mid-late-Holocene age (0.1-8??ka) that correspond to marine low-stand and marine high-stand conditions, respectively. The distribution of both the late-Pleistocene dune sheets (516??km2 total surface area) and the late-Holocene dune sheets (184??km2) are concentrated (90% of total surface area) along a 100??km coastal reach of the south-central Oregon coast. This coastal reach lies directly landward of a major bight (Heceta-Perpetua-Stonewall Banks) on the continental shelf, at depths of 30-200??m below present mean sea level (MSL). The banks served to trap northward littoral drift during most of the late-Pleistocene conditions of lowered sea level (- 50 ?? 20??m MSL). The emerged inner-shelf permitted cross-shelf, eolian sand transport (10-50??km distance) by onshore winds. The depocenter sand deposits were reworked by the Holocene marine transgression and carried landward by asymmetric wave transport during early- to mid-Holocene time. The earliest dated onset of Holocene dune accretion occurred at 8??ka in the central Oregon coast. A northward migration of Northeast Pacific storm tracks to the latitude of the shelf depocenter (Stonewall, Perpetua, Heceta Banks) in Holocene time resulted in eastward wave transport from the offshore depocenter. The complex interplay of coastal morphology, paleosea-level, and paleoclimate yielded the observed peak distribution of beach and dune sand observed along the south-central Oregon coast. ?? 2007 Elsevier B.V. All rights reserved.

Refractive errors in a Brazilian population: age and sex distribution.

PubMed

Ferraz, Fabio H; Corrente, José E; Opromolla, Paula; Padovani, Carlos Roberto; Schellini, Silvana A

2015-01-01

To determine the prevalence of refractive errors and their distribution according to age and sex in a Brazilian population. This population-based cross-sectional study involved 7654 Brazilian inhabitants of nine municipalities of Sao Paulo State, Brazil, between March 2004 and July 2005. Participants aged >1 year were selected using a random, stratified, household cluster sampling technique, excluding individuals with previous refractive or cataract surgery. Myopia was defined as spherical equivalent (SE) ≤-0.5D, high myopia as SE ≤-3.0D, hyperopia as SE ≥+0.5D, high hyperopia as SE ≥+3D, astigmatism as ≤-0.5DC and anisometropia as ≥1.0D difference between eyes. Age, sex, complaints and a comprehensive eye examination including cycloplegic refraction test were collected and analysed using descriptive analysis, univariate and multivariate methods. The prevalence of astigmatism was 59.7%, hyperopia 33.8% and myopia was 25.3%. Astigmatism had a progressive increase with age. With-the-rule (WTR) axes of astigmatism were more frequently observed in the young participants and the against-the-rule (ATR) axes were more frequent in the older subjects. The onset of myopia occurred more frequently between the 2nd and 3rd decades of life. Anisometropia showed a prevalence of 13.2% (95% CI 12.4-13.9; p < 0.001). There was an association between age and all types of refractive error and hyperopia was also associated with sex. Hyperopia was associated with WTR axes (odds ratio 0.73; 95% CI: 0.6-0.8; p < 0.001) and myopia with ATR axes (odds ratio 0.66; 95% CI: 0.6-0.8; p < 0.001). Astigmatism was the most prevalent refractive error in a Brazilian population. There was a strong relationship between age and all refractive errors and between hyperopia and sex. WTR astigmatism was more frequently associated with hyperopia and ATR astigmatism with myopia. The vast majority of participants had low-grade refractive error, which favours planning aimed at correction of

A novel approach to molecular similarity

NASA Astrophysics Data System (ADS)

Cooper, David L.; Allan, Neil L.

1989-09-01

We review briefly the general problem of assessing the similarity between one molecule and another. We propose a novel approach to the quantitative estimation of the similarity of two electron distributions. The procedure is based on momentum space concepts, and avoids many of the difficulties associated with the usual position space definitions. Results are presented for the model systems CH3CH2CH3, CH3OCH3, CH3SCH3, H2O and H2S.

Looking for a correlation between terrestrial age and noble gas record of H chondrites

NASA Astrophysics Data System (ADS)

Loeken, Th.; Schultz, L.

1994-07-01

On the basis of statistically significant concentration differences of some trace elements, it has been suggested that H chondrites found in Antarctica and Modern Falls represent members of different extraterrestrial populations with different thermal histories. It was also concluded that H chondrites found in Victoria Land (Allan Hills) differ chemically from those found in Queen Maud Land (Yamato Mountains), an effect that could be based on the different terrestrial age distribution of both groups. This would imply a change of the meteoroid flux hitting the Earth on a timescale that is comparable to typical terrestrial ages of Antarctic chondrites. A comparison of the noble gas record of H chondrites from the Allan Hills icefields and Modern Fall shows that the distributions of cosmic-ray exposure ages and the concentrations of radiogenic He-4 and Ar-40 are very similar. In an earlier paper we compared the noble gas measurements of 20 Yamato H contents with meteorites from the Allan Hills region and Modern Falls. Similar distributions were found. The distribution of cosmic-ray exposure ages and radiogenic He-4 and Ar-40 gas contents as a function of the terrestrial age is investigated in these chondrites. The distribution shows the well-known 7-Ma-cluster indicating that about 40% of the H chondrites were excavated from their parent body in a single event. Both populations, Antarctic Meteorites and Modern Falls, exhibit the same characteristic feature: a major meteoroid-producing event about 7 Ma. This indicates that one H-group population delivers H chondrites to Antarctica and the rest of the world. Cosmic-ray exposure ages and thermal-history indicaters like radiogenic noble gases show no evidence of a change in the H chondrite meteoroid population during the last 200,000 years.

Three ages of Venus

NASA Technical Reports Server (NTRS)

Wood, Charles A.; Coombs, Cassandra R.

1989-01-01

A central question for any planet is the age of its surface. Based on comparative planetological arguments, Venus should be as young and active as the Earth (Wood and Francis). The detection of probable impact craters in the Venera radar images provides a tool for estimating the age of the surface of Venus. Assuming somewhat different crater production rates, Bazilevskiy et al. derived an age of 1 + or - 0.5 billion years, and Schaber et al. and Wood and Francis estimated an age of 200 to 400 million years. The known impact craters are not randomly distributed, however, thus some area must be older and others younger than this average age. Ages were derived for major geologic units on Venus using the Soviet catalog of impact craters (Bazilevskiy et al.), and the most accessible geologic unit map (Bazilevskiy). The crater counts are presented for (diameters greater than 20 km), areas, and crater densities for the 7 terrain units and coronae. The procedure for examining the distribution of craters is superior to the purely statistical approaches of Bazilevskiy et al. and Plaut and Arvidson because the bins are larger (average size 16 x 10(6) sq km) and geologically significant. Crater densities define three distinct groups: relatively heavily cratered (Lakshmi, mountain belts), moderately cratered (smooth and rolling plains, ridge belts, and tesserae), and essentially uncratered (coronae and domed uplands). Following Schaber et al., Grieve's terrestrial cratering rate of 5.4 + or - 2.7 craters greater than 20 km/10(9) yrs/10(6) sq km was used to calculate ages for the geologic units on Venus. To improve statistics, the data was aggregated into the three crater density groups, deriving the ages. For convenience, the three similar age groups are given informal time stratigraphic unit names, from youngest to oldest: Ulfrunian, Sednaian, Lakshmian.

Three ages of Venus

NASA Astrophysics Data System (ADS)

Wood, Charles A.; Coombs, Cassandra R.

A central question for any planet is the age of its surface. Based on comparative planetological arguments, Venus should be as young and active as the Earth (Wood and Francis). The detection of probable impact craters in the Venera radar images provides a tool for estimating the age of the surface of Venus. Assuming somewhat different crater production rates, Bazilevskiy et al. derived an age of 1 + or - 0.5 billion years, and Schaber et al. and Wood and Francis estimated an age of 200 to 400 million years. The known impact craters are not randomly distributed, however, thus some area must be older and others younger than this average age. Ages were derived for major geologic units on Venus using the Soviet catalog of impact craters (Bazilevskiy et al.), and the most accessible geologic unit map (Bazilevskiy). The crater counts are presented for (diameters greater than 20 km), areas, and crater densities for the 7 terrain units and coronae. The procedure for examining the distribution of craters is superior to the purely statistical approaches of Bazilevskiy et al. and Plaut and Arvidson because the bins are larger (average size 16 x 10(6) sq km) and geologically significant. Crater densities define three distinct groups: relatively heavily cratered (Lakshmi, mountain belts), moderately cratered (smooth and rolling plains, ridge belts, and tesserae), and essentially uncratered (coronae and domed uplands). Following Schaber et al., Grieve's terrestrial cratering rate of 5.4 + or - 2.7 craters greater than 20 km/10(9) yrs/10(6) sq km was used to calculate ages for the geologic units on Venus. To improve statistics, the data was aggregated into the three crater density groups, deriving the ages. For convenience, the three similar age groups are given informal time stratigraphic unit names, from youngest to oldest: Ulfrunian, Sednaian, Lakshmian.

Patent foramen ovale in a large population of ischemic stroke patients: diagnosis, age distribution, gender, and race.

PubMed

Gupta, Vishal; Yesilbursa, Dilek; Huang, Wen Ying; Aggarwal, Kul; Gupta, Vijaya; Gomez, Camilo; Patel, Vinod; Miller, Andrew P; Nanda, Navin C

2008-02-01

Patent foramen ovale (PFO) is a well-recognized risk factor for ischemic strokes. The true prevalence of PFO among stroke patients is still under debate. Transesophageal echocardiography (TEE) is the "gold standard" in diagnosing PFO but the physiology requires right-to-left atrial shunting. In this report, we evaluate the prevalence of PFO in a diverse group of ischemic stroke patients studied by TEE. TEE of 1,663 ischemic stroke patients were reviewed for cardiac source of embolism, including PFO and atrial septal aneurysm (ASA). Agitated saline bubble injection was performed to look for right to left atrial shunting. Success of maneuvers to elevate right atrial pressure (RAP) was noted by looking at the atrial septal bulge. Among 1,435 ischemic stroke patients analyzed, the presence or absence of PFO could not be determined in 32.1% because bulging of the septum could not be demonstrated in patients with negative contrast study despite aggressive maneuvers to elevate RAP. Of the remaining 974 patients, 294 patients (30.2%) had a PFO. The mean age was 61.5 years in both groups, with a bimodal distribution of PFO and the highest prevalence occurring in < or =30-year-old group. Prevalence of PFO was similar in men (32.4%) and women (28.15%, P = 0.15); and in Caucasian (32.1%) and African American (27.7%; P = 0.15). ASA was present in 2.02% and hypermobile septum in 2.49% of the 1,435 patients. PFO was seen in 79.3% of the patients with ASA. Successful elevation of RAP cannot be achieved in a significant number of patients undergoing TEE and determination of PFO may be difficult. In our series, the true prevalence of PFO among ischemic stroke patients was 30.2% taking into account only those patients who showed no shunting despite bulging of the atrium septum into the left atrium (PFO absent group) during the contrast study. There was no gender or racial difference in the prevalence of PFO, but there was a bimodal distribution in prevalence with age.

Structural similarity and distribution of small cryptic plasmids of Lactobacillus curvatus and L. sake.

PubMed

Vogel, R F; Lohmann, M; Weller, A N; Hugas, M; Hammes, W P

1991-11-15

Plasmid profiles of strains of Lactobacillus curvatus and L. sake isolated from meat or sauerkraut were analysed to investigate plasmid homology and distribution in relation to the ecology of these organisms in fermenting foods. A hybridisation probe was constructed by cloning of pLc2, a cryptic, 2.6-kbp plasmid from L. curvatus LTH683, into the Escherichia coli plasmid pRV50. In Southern hybridisations with the digoxygenine labeled pLc2 probe, pLc2-related small plasmids were frequently detected in meat-borne strains of L. casei subsp. pseudoplantarum, L. curvatus, L. sake, L. alimentarius, L. farciminis and L. halotolerans and in L. curvatus and L. sake isolated from sauerkraut. Among 27 Lactobacillus type strains originally isolated from habitats other than meat this type of homology was detected only with plasmids of L. buchneri and L. mali. Restriction-enzyme mapping of six small cryptic plasmids from L. curvatus and L. sake revealed strong structural homology but no similarity to previously characterized plasmids of lactobacilli. The presence of a variable region in addition to a conserved one and the occurrence of deletions during cloning of pLc2 suggest that vectors derived from these plasmids are likely to be structurally unstable.

Colour homogeneity and visual perception of age, health and attractiveness of male facial skin.

PubMed

Fink, B; Matts, P J; D'Emiliano, D; Bunse, L; Weege, B; Röder, S

2012-12-01

Visible facial skin condition in females is known to affect perception of age, health and attractiveness. Skin colour distribution in shape- and topography-standardized female faces, driven by localized melanin and haemoglobin, can account for up to twenty years of apparent age perception. Although this is corroborated by an ability to discern female age even in isolated, non-contextual skin images, a similar effect in the perception of male skin is yet to be demonstrated. To investigate the effect of skin colour homogeneity and chromophore distribution on the visual perception of age, health and attractiveness of male facial skin. Cropped images from the cheeks of facial images of 160 Caucasian British men aged 10-70 years were blind-rated for age, health and attractiveness by a total of 308 participants. In addition, the homogeneity of skin images and corresponding eumelanin/oxyhaemoglobin concentration maps were analysed objectively using Haralick's image segmentation algorithm. Isolated skin images taken from the cheeks of younger males were judged as healthier and more attractive. Perception of age, health and attractiveness was strongly related to melanin and haemoglobin distribution, whereby more even distributions led to perception of younger age and greater health and attractiveness. The evenness of melanized features was a stronger cue for age perception, whereas haemoglobin distribution was associated more strongly with health and attractiveness perception. Male skin colour homogeneity, driven by melanin and haemoglobin distribution, influences perception of age, health and attractiveness. © 2011 The Authors. Journal of the European Academy of Dermatology and Venereology © 2011 European Academy of Dermatology and Venereology.

Effect of river sediment on phosphorus chemistry of similarly aged natural and created wetlands in the Atchafalaya Delta, Louisiana, USA

USGS Publications Warehouse

Poach, M.E.; Faulkner, S.P.

2007-01-01

The goal of wetland creation is to produce an artificial wetland that functions as a natural wetland. Studies comparing created wetlands to similarly aged natural wetlands provide important information about creation techniques and their improvement so as to attain that goal. We hypothesized that differences in sediment phosphorus accretion, deposition, and chemistry between created and natural wetlands in the Atchafalaya Delta, Louisiana, USA were a function of creation technique and natural river processes. Sediment deposition was determined with feldspar marker horizons located in created and natural wetlands belonging to three age classes (<3, 5-10, and 15-20 yr old). Phosphorus fractions were measured in these deposited sediments and in suspended and bedload sediment from the Atchafalaya River. Bedload sediment had significantly lower iron- and aluminum-bound, reductant-soluble, and total phosphorus than suspended sediment due to its high sand percentage. This result indicates that wetlands artificially created in the Atchafalaya Delta using bedload sediment will initially differ from natural wetlands of the same age. Even so, similarities between the mudflat stratum of the <1- to 3-yr-old created wetland and the mudflat stratum of the 15- to 20-yr-old natural wetland support the contention that created wetlands in the Atchafalaya Delta can develop natural characteristics through the deposition of river suspended sediment. Differences between three created wetland strata, the 15- to 20-yr-old willow stratum and the < 1- to 3-yr-old willow and mixed marsh strata, and their natural counterparts were linked to design elements of the created wetlands that prevented the direct deposition of the river's suspended sediment. ?? ASA, CSSA, SSSA.

Bubble statistics in aged wet foams and the Fokker-Planck equation

NASA Astrophysics Data System (ADS)

Zimnyakov, D. A.; Yuvchenko, S. A.; Tzyipin, D. V.; Samorodina, T. V.

2018-04-01

Results of the experimental study of changes in the bubble size statistics during aging of wet foams are discussed. It is proposed that the evolution of the bubble radii distributions can be described in terms of the one dimensional Fokker- Planck equation. The empirical distributions of the bubble radii exhibit a self-similarity of their shapes and can be transformed to a time-independent form using the radius renormalization. Analysis of obtained data allows us to suggest that the drift term of the Fokker-Planck equation dominates in comparison with the diffusion term in the case of aging of isolated quasi-stable wet foams.

Acute coronary syndrome in women of reproductive age

PubMed Central

Idris, Nazimah; Aznal, Sharifah Sulaiha; Chin, Sze-Piaw; Ahmad, Wan Azman Wan; Rosman, Azhari; Jeyaindran, Sinnadurai; Ismail, Omar; Zambahari, Robaayah; Sim, Kui Hian

2011-01-01

Background There is scarce or no data on prevalence and presentation of acute coronary syndrome (ACS) among women of reproductive age. Furthermore, whether women of reproductive age presenting with ACS have the same risk factors as men and older women is not known. Objective To analyze factors associated with ACS in women of reproductive age in comparison with older women and men of a similar age group. Methodology A total of 9702 cases of acute coronary syndrome over a 3-year period ( 2006–2008) from the National Cardiovascular Disease database were analyzed, with focus on women of reproductive age (20–<40 years), looking into association with ethnicity, comorbid illness, and the ACS stratum. Comparison with older women (40–<60 years; Control 1) and men of similar age group (Control 2) was made and analyzed using Fisher’s exact test and chi-square test when necessary. Results From a total of 9702 cases, 2344 (24.2%) were women. Of these, 45 (1.9%) were women between 20 and <40 years, which is significantly lower than the two controls (older women 30.8%, and men of same age 6.2%, respectively; P < 0.0001). The distribution of ethnicity shows a similar pattern between the study group and the controls, but patients of Indian ethnicity were over-represented when compared with the Malaysian demographics of general population (31.3% versus 7.1%; P < 0.0001). ACS in women of reproductive age was associated with diabetes mellitus in 37.8%, hypertension in 40.0%, and dyslipidemia in 24.4% of cases, similar to men of the same age but significantly lower than the older women (P < 0.0001). Smoking is not a major risk factor in the study group, where only 6.7% ever smoked, similar to older women (6.8%, P = 1.000) and significantly much less compared with men of the same age (84.1%; P < 0.0001). Regarding the ACS stratum, a significantly higher percentage of women in the study group had ST-segment elevation myocardial infarction compared with older women (P = 0

Patterns and age distribution of ground-water flow to streams

USGS Publications Warehouse

Modica, E.; Reilly, T.E.; Pollock, D.W.

1997-01-01

Simulations of ground-water flow in a generic aquifer system were made to characterize the topology of ground-water flow in the stream subsystem and to evaluate its relation to deeper ground-water flow. The flow models are patterned after hydraulic characteristics of aquifers of the Atlantic Coastal Plain and are based on numerical solutions to three-dimensional, steady-state, unconfined flow. The models were used to evaluate the effects of aquifer horizontal-to-vertical hydraulic conductivity ratios, aquifer thickness, and areal recharge rates on flow in the stream subsystem. A particle tracker was used to determine flow paths in a stream subsystem, to establish the relation between ground-water seepage to points along a simulated stream and its source area of flow, and to determine ground-water residence time in stream subsystems. In a geometrically simple aquifer system with accretion, the source area of flow to streams resembles an elongated ellipse that tapers in the downgradient direction. Increased recharge causes an expansion of the stream subsystem. The source area of flow to the stream expands predominantly toward the stream headwaters. Baseflow gain is also increased along the reach of the stream. A thin aquifer restricts ground-water flow and causes the source area of flow to expand near stream headwaters and also shifts the start-of-flow to the drainage basin divide. Increased aquifer anisotropy causes a lateral expansion of the source area of flow to streams. Ground-water seepage to the stream channel originates both from near- and far-recharge locations. The range in the lengths of flow paths that terminate at a point on a stream increase in the downstream direction. Consequently, the age distribution of ground water that seeps into the stream is skewed progressively older with distance downstream. Base flow ia an integration of ground water with varying age and potentially different water quality, depending on the source within the drainage basin

Comparability of the age and sex distribution of the UK Clinical Practice Research Datalink and the total Dutch population.

PubMed

de Jong, Roy G P J; Gallagher, Arlene M; Herrett, Emily; Masclee, Ad A M; Janssen-Heijnen, Maryska L G; de Vries, Frank

2016-12-01

The UK Clinical Practice Research Datalink (CPRD) is increasingly being used by Dutch researchers in epidemiology and pharmacoepidemiology. It is however unclear if the UK CPRD is representative of the Dutch population and whether study results would apply to the Dutch population. Therefore, as first step, our objective was to compare the age and sex distribution of the CPRD with the total Dutch population. As a measure of representativeness, the age and sex distribution of the UK CPRD were visually and numerically compared with Dutch census data from the StatLine database of the Dutch National Bureau of Statistics in 2011. The age distribution of men and women in the CPRD population was comparable to the Dutch male and female population. Differences of more than 10% only occurred in older age categories (75+ in men and 80+ in women). Results from observational studies that have used CPRD data are applicable to the Dutch population, and a useful resource for decision making in the Netherlands. Nevertheless, differences in drug exposure likelihood between countries should be kept in mind, as these could still cause variations in the actual population studied, thereby decreasing its generalizability. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Dyslexic and Skilled Reading Dynamics Are Self-Similar

ERIC Educational Resources Information Center

Holden, John G.; Greijn, Lieke T.; van Rooij, Marieke M. J. W.; Wijnants, Maarten L.; Bosman, Anna M. T.

2014-01-01

The shape of a word pronunciation time distribution supplies information about the dynamic interactions that support reading performance. Speeded word-naming pronunciation and response time distributions were collected from 20 sixth grade Dutch students with dyslexia and 23 age-matched controls. The participants' pronunciation times were modeled…

DNA damage and ageing: new-age ideas for an age-old problem

PubMed Central

Garinis, George A.; van der Horst, Gijsbertus T. J.; Vijg, Jan; Hoeijmakers, Jan H. J.

2015-01-01

Loss of genome maintenance may causally contribute to ageing, as exemplified by the premature appearance of multiple symptoms of ageing in a growing family of human syndromes and in mice with genetic defects in genome maintenance pathways. Recent evidence revealed a similarity between such prematurely ageing mutants and long-lived mice harbouring mutations in growth signalling pathways. At first sight this seems paradoxical as they represent both extremes of ageing yet show a similar ‘survival’ response that is capable of delaying age-related pathology and extending lifespan. Understanding the mechanistic basis of this response and its connection with genome maintenance would open exciting possibilities for counteracting cancer or age-related diseases, and for promoting longevity. PMID:18978832

Mapping for maternal and newborn health: the distributions of women of childbearing age, pregnancies and births.

PubMed

Tatem, Andrew J; Campbell, James; Guerra-Arias, Maria; de Bernis, Luc; Moran, Allisyn; Matthews, Zoë

2014-01-04

The health and survival of women and their new-born babies in low income countries has been a key priority in public health since the 1990s. However, basic planning data, such as numbers of pregnancies and births, remain difficult to obtain and information is also lacking on geographic access to key services, such as facilities with skilled health workers. For maternal and newborn health and survival, planning for safer births and healthier newborns could be improved by more accurate estimations of the distributions of women of childbearing age. Moreover, subnational estimates of projected future numbers of pregnancies are needed for more effective strategies on human resources and infrastructure, while there is a need to link information on pregnancies to better information on health facilities in districts and regions so that coverage of services can be assessed. This paper outlines demographic mapping methods based on freely available data for the production of high resolution datasets depicting estimates of numbers of people, women of childbearing age, live births and pregnancies, and distribution of comprehensive EmONC facilities in four large high burden countries: Afghanistan, Bangladesh, Ethiopia and Tanzania. Satellite derived maps of settlements and land cover were constructed and used to redistribute areal census counts to produce detailed maps of the distributions of women of childbearing age. Household survey data, UN statistics and other sources on growth rates, age specific fertility rates, live births, stillbirths and abortions were then integrated to convert the population distribution datasets to gridded estimates of births and pregnancies. These estimates, which can be produced for current, past or future years based on standard demographic projections, can provide the basis for strategic intelligence, planning services, and provide denominators for subnational indicators to track progress. The datasets produced are part of national midwifery

Mapping for maternal and newborn health: the distributions of women of childbearing age, pregnancies and births

PubMed Central

2014-01-01

Background The health and survival of women and their new-born babies in low income countries has been a key priority in public health since the 1990s. However, basic planning data, such as numbers of pregnancies and births, remain difficult to obtain and information is also lacking on geographic access to key services, such as facilities with skilled health workers. For maternal and newborn health and survival, planning for safer births and healthier newborns could be improved by more accurate estimations of the distributions of women of childbearing age. Moreover, subnational estimates of projected future numbers of pregnancies are needed for more effective strategies on human resources and infrastructure, while there is a need to link information on pregnancies to better information on health facilities in districts and regions so that coverage of services can be assessed. Methods This paper outlines demographic mapping methods based on freely available data for the production of high resolution datasets depicting estimates of numbers of people, women of childbearing age, live births and pregnancies, and distribution of comprehensive EmONC facilities in four large high burden countries: Afghanistan, Bangladesh, Ethiopia and Tanzania. Satellite derived maps of settlements and land cover were constructed and used to redistribute areal census counts to produce detailed maps of the distributions of women of childbearing age. Household survey data, UN statistics and other sources on growth rates, age specific fertility rates, live births, stillbirths and abortions were then integrated to convert the population distribution datasets to gridded estimates of births and pregnancies. Results and conclusions These estimates, which can be produced for current, past or future years based on standard demographic projections, can provide the basis for strategic intelligence, planning services, and provide denominators for subnational indicators to track progress. The datasets

Spatial distribution and optimal harvesting of an age-structured population in a fluctuating environment.

PubMed

Engen, Steinar; Lee, Aline Magdalena; Sæther, Bernt-Erik

2018-02-01

We analyze a spatial age-structured model with density regulation, age specific dispersal, stochasticity in vital rates and proportional harvesting. We include two age classes, juveniles and adults, where juveniles are subject to logistic density dependence. There are environmental stochastic effects with arbitrary spatial scales on all birth and death rates, and individuals of both age classes are subject to density independent dispersal with given rates and specified distributions of dispersal distances. We show how to simulate the joint density fields of the age classes and derive results for the spatial scales of all spatial autocovariance functions for densities. A general result is that the squared scale has an additive term equal to the squared scale of the environmental noise, corresponding to the Moran effect, as well as additive terms proportional to the dispersal rate and variance of dispersal distance for the age classes and approximately inversely proportional to the strength of density regulation. We show that the optimal harvesting strategy in the deterministic case is to harvest only juveniles when their relative value (e.g. financial) is large, and otherwise only adults. With increasing environmental stochasticity there is an interval of increasing length of values of juveniles relative to adults where both age classes should be harvested. Harvesting generally tends to increase all spatial scales of the autocovariances of densities. Copyright © 2017. Published by Elsevier Inc.

Age- and Hypertension-Associated Protein Aggregates in Mouse Heart Have Similar Proteomic Profiles.

PubMed

Ayyadevara, Srinivas; Mercanti, Federico; Wang, Xianwei; Mackintosh, Samuel G; Tackett, Alan J; Prayaga, Sastry V S; Romeo, Francesco; Shmookler Reis, Robert J; Mehta, Jawahar L

2016-05-01

Neurodegenerative diseases are largely defined by protein aggregates in affected tissues. Aggregates contain some shared components as well as proteins thought to be specific for each disease. Aggregation has not previously been reported in the normal, aging heart or the hypertensive heart. Detergent-insoluble protein aggregates were isolated from mouse heart and characterized on 2-dimensional gels. Their levels increased markedly and significantly with aging and after sustained angiotensin II-induced hypertension. Of the aggregate components identified by high-resolution proteomics, half changed in abundance with age (392/787) or with sustained hypertension (459/824), whereas 30% (273/901) changed concordantly in both, each P<0.05. One fifth of these proteins were previously associated with age-progressive neurodegenerative or cardiovascular diseases, or both (eg, ApoE, ApoJ, ApoAIV, clusterin, complement C3, and others involved in stress-response and protein-homeostasis pathways). Because fibrosis is a characteristic of both aged and hypertensive hearts, we posited that aging of fibroblasts may contribute to the aggregates observed in cardiac tissue. Indeed, as cardiac myofibroblasts "senesced" (approached their replicative limit) in vitro, they accrued aggregates with many of the same constituent proteins observed in vivo during natural aging or sustained hypertension. In summary, we have shown for the first time that compact (detergent-insoluble) protein aggregates accumulate during natural aging, chronic hypertension, and in vitro myofibroblast senescence, sharing many common proteins. Thus, aggregates that arise from disparate causes (aging, hypertension, and replicative senescence) may have common underlying mechanisms of accrual. © 2016 American Heart Association, Inc.

Relationship between pure Schistosoma haematobium infection in Upper Egypt and irrigation systems. Part II: Host characteristics. The general prevalence of Schistosoma haematobium, age and sex distribution.

PubMed

Hammam, H M; Allam, F A; Hassanein, F

1975-01-01

The epidemiology of bilharziasis was studied in four villages in Assiut Governorate. These villages were almost similar with respect to their socioeconomic conditions, modes of living, availability and date of introduction of medical services. The first village, Gezirat El-Maabda, has a basin system of irrigation. The other three villages had shifted to the perennial system of irrigation for three years in Nazza Karrar, 26 years in El-Ghorayeb and 95 years in Garf Sarhan and were similar with respect to proximity to water courses. So the only variable of importance between the four villages was the mode of irrigation. Bilharziasis was diagnosed by detection of eggs in urine or faeces. A definitive relationship between the prevalence of S. haematobium infection and the type of irrigation system was further documented. A low prevalence was found in Gezirat El-Maabda (2.95%). In the other three villages a much higher prevalence existed (31.9%, 46.2% & 38.9% in Nazza Karar, El-Ghorayeb and Garf Sarhan respectively). The higher prevalence of S. haematobium in Nazza Karar (31.9%) only three years after introduction of perennial irrigation was a disappointing finding. It can be considered as an evidence against the elaborate measures and precautions planned and incompletely implemented before or after the establishment of Aswan High Dam. Not a single case of S. mansoni was encountered during this study. As regards the age and sex distribution of S. haematobium in the three villages irrigated perennially, a steep rise started at the age group 5-9 years reaching a peak at the age group 10-14 years. In Gezirat El-Maabda the peak was reached at later age (15-19 years). The cause of this difference was explained. Males showed a higher rate of infection than females in almost all age groups of the four village studied.

Anatomical distribution and detection rate of colorectal neoplasms according to age in the colonoscopic screening of a Korean population.

PubMed

Lee, Suk-Young; Song, Wan Hee; Oh, Sang Cheul; Min, Byung-Wook; Lee, Sun Il

2018-01-01

Because data as a basis for the determination of proper age and modality for screening of colorectal neoplasms is lacking, we evaluated detection rates and anatomical distribution of colorectal neoplasms according to age in healthy individuals who underwent total colonoscopy for health checkup. A total of 16,100 cases that had received the colonoscopic examination from January to December in 2014 were analyzed. The total number of individuals who received total colonoscopy were divided by the number of individuals harboring colorectal adenoma to calculate the detection rate of colorectal adenoma. Individuals ≤50 years old were classified as young-age group and aged >50 were old-age group. Differences in anatomical locations of colorectal neoplasms were analyzed in the 2 age groups by chi-square test. Risk factors for colorectal adenoma in each age group were analyzed using univariate and multivariate logistic regression analyses. Detection rates of colorectal adenoma were 13.7% in all cases and 12.8% for those in their 40's. The main anatomical location of colorectal adenoma was proximal colon in both age groups (P < 0.001). Hyperplastic polyp was mainly distributed to the distal colon in both age groups (P < 0.001). Distal colon was the major site for colorectal cancer in the old-age group (P = 0.001). Proximal location of neoplasms was a risk factor for colorectal adenoma in both age groups with multivariate analysis. These data could be the bases for earlier initiation of screening for colorectal neoplasms with total colonoscopy to detect clinically significant colorectal polyps.

Saxagliptin is similar in glycaemic variability more effective in metabolic control than acarbose in aged type 2 diabetes inadequately controlled with metformin.

PubMed

Wang, Man-man; Lin, Shuo; Chen, Yan-ming; Shu, Jiong; Lu, Hong-yun; Zhang, Yong-jun; Xie, Ru-ying; Zeng, Long-yi; Mu, Pan-wei

2015-06-01

This study compared the effects on glycaemic variability and glucose control between saxagliptin and acarbose as add-on therapies for aged T2DM inadequately controlled with metformin alone. The results showed that compared with acarbose-metformin, saxagliptin-metformin was more effective in glucose control with similar glycaemic variability. Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

On Prolonging Network Lifetime through Load-Similar Node Deployment in Wireless Sensor Networks

PubMed Central

Li, Qiao-Qin; Gong, Haigang; Liu, Ming; Yang, Mei; Zheng, Jun

2011-01-01

This paper is focused on the study of the energy hole problem in the Progressive Multi-hop Rotational Clustered (PMRC)-structure, a highly scalable wireless sensor network (WSN) architecture. Based on an analysis on the traffic load distribution in PMRC-based WSNs, we propose a novel load-similar node distribution strategy combined with the Minimum Overlapping Layers (MOL) scheme to address the energy hole problem in PMRC-based WSNs. In this strategy, sensor nodes are deployed in the network area according to the load distribution. That is, more nodes shall be deployed in the range where the average load is higher, and then the loads among different areas in the sensor network tend to be balanced. Simulation results demonstrate that the load-similar node distribution strategy prolongs network lifetime and reduces the average packet latency in comparison with existing nonuniform node distribution and uniform node distribution strategies. Note that, besides the PMRC structure, the analysis model and the proposed load-similar node distribution strategy are also applicable to other multi-hop WSN structures. PMID:22163809

The Relationship of Loss, Mean Age of Air and the Distribution of CFC's to Stratospheric Circulation and Implications for Atmospheric Lifetimes

NASA Technical Reports Server (NTRS)

Douglas, A. R.; Stolarski, R. S.; Schoeberl, M. R.; Jackman, C. H.; Gupta, M. L.; Newman, P. A.; Nielsen, J. E.; Fleming, E. L.

2008-01-01

Model-derived estimates of the annually integrated destruction and lifetime for various ozone depleting substances (ODSs) depend on the simulated stratospheric transport and mixing in the global model used to produce the estimate. Observations in the middle and high latitude lower stratosphere show that the mean age of an air parcel (i.e., the time since its stratospheric entry) is related to the fractional release for the ODs (i.e., the amount of the ODS that has been destroyed relative to the amount at the time of stratospheric entry). We use back trajectory calculations to produce an age spectrum, and explain the relationship between the mean age and the fractional release by showing that older elements in the age spectrum have experienced higher altitudes and greater ODs destruction than younger elements. In our study, models with faster circulations produce distributions for the age-of-air that are 'young' compared to a distribution derived from observations. These models also fail to reproduce the observed relationship between the mean age of air and the fractional release. Models with slower circulations produce both realistic distributions for mean age and a realistic relationship between mean age and fractional release. These models also produce a CFCl3 lifetime of approximately 56 years, longer than the 45 year lifetime used to project future mixing ratios. We find that the use of flux boundary conditions in assessment models would have several advantages, including consistency between ODS evolution and simulated loss even if the simulated residual circulation changes due to climate change.

Predicting the performance of fingerprint similarity searching.

PubMed

Vogt, Martin; Bajorath, Jürgen

2011-01-01

Fingerprints are bit string representations of molecular structure that typically encode structural fragments, topological features, or pharmacophore patterns. Various fingerprint designs are utilized in virtual screening and their search performance essentially depends on three parameters: the nature of the fingerprint, the active compounds serving as reference molecules, and the composition of the screening database. It is of considerable interest and practical relevance to predict the performance of fingerprint similarity searching. A quantitative assessment of the potential that a fingerprint search might successfully retrieve active compounds, if available in the screening database, would substantially help to select the type of fingerprint most suitable for a given search problem. The method presented herein utilizes concepts from information theory to relate the fingerprint feature distributions of reference compounds to screening libraries. If these feature distributions do not sufficiently differ, active database compounds that are similar to reference molecules cannot be retrieved because they disappear in the "background." By quantifying the difference in feature distribution using the Kullback-Leibler divergence and relating the divergence to compound recovery rates obtained for different benchmark classes, fingerprint search performance can be quantitatively predicted.

Estimating Age Distributions of Base Flow in Watersheds Underlain by Single and Dual Porosity Formations Using Groundwater Transport Simulation and Weighted Weibull Functions

NASA Astrophysics Data System (ADS)

Sanford, W. E.

2015-12-01

Age distributions of base flow to streams are important to estimate for predicting the timing of water-quality responses to changes in distributed inputs of nutrients or pollutants at the land surface. Simple models of shallow aquifers will predict exponential age distributions, but more realistic 3-D stream-aquifer geometries will cause deviations from an exponential curve. In addition, in fractured rock terrains the dual nature of the effective and total porosity of the system complicates the age distribution further. In this study shallow groundwater flow and advective transport were simulated in two regions in the Eastern United States—the Delmarva Peninsula and the upper Potomac River basin. The former is underlain by layers of unconsolidated sediment, while the latter consists of folded and fractured sedimentary rocks. Transport of groundwater to streams was simulated using the USGS code MODPATH within 175 and 275 watersheds, respectively. For the fractured rock terrain, calculations were also performed along flow pathlines to account for exchange between mobile and immobile flow zones. Porosities at both sites were calibrated using environmental tracer data (3H, 3He, CFCs and SF6) in wells and springs, and with a 30-year tritium record from the Potomac River. Carbonate and siliciclastic rocks were calibrated to have mobile porosity values of one and six percent, and immobile porosity values of 18 and 12 percent, respectively. The age distributions were fitted to Weibull functions. Whereas an exponential function has one parameter that controls the median age of the distribution, a Weibull function has an extra parameter that controls the slope of the curve. A weighted Weibull function was also developed that potentially allows for four parameters, two that control the median age and two that control the slope, one of each weighted toward early or late arrival times. For both systems the two-parameter Weibull function nearly always produced a substantially

HRV-derived data similarity and distribution index based on ensemble neural network for measuring depth of anaesthesia.

PubMed

Liu, Quan; Ma, Li; Chiu, Ren-Chun; Fan, Shou-Zen; Abbod, Maysam F; Shieh, Jiann-Shing

2017-01-01

Evaluation of depth of anaesthesia (DoA) is critical in clinical surgery. Indices derived from electroencephalogram (EEG) are currently widely used to quantify DoA. However, there are known to be inaccurate under certain conditions; therefore, experienced anaesthesiologists rely on the monitoring of vital signs such as body temperature, pulse rate, respiration rate, and blood pressure to control the procedure. Because of the lack of an ideal approach for quantifying level of consciousness, studies have been conducted to develop improved methods of measuring DoA. In this study, a short-term index known as the similarity and distribution index (SDI) is proposed. The SDI is generated using heart rate variability (HRV) in the time domain and is based on observations of data distribution differences between two consecutive 32 s HRV data segments. A comparison between SDI results and expert assessments of consciousness level revealed that the SDI has strong correlation with anaesthetic depth. To optimise the effect, artificial neural network (ANN) models were constructed to fit the SDI, and ANN blind cross-validation was conducted to overcome random errors and overfitting problems. An ensemble ANN was then employed and was discovered to provide favourable DoA assessment in comparison with commonly used Bispectral Index. This study demonstrated the effectiveness of this method of DoA assessment, and the results imply that it is feasible and meaningful to use the SDI to measure DoA with the additional use of other measurement methods, if appropriate.

THE STELLAR AGES AND MASSES OF SHORT GAMMA-RAY BURST HOST GALAXIES: INVESTIGATING THE PROGENITOR DELAY TIME DISTRIBUTION AND THE ROLE OF MASS AND STAR FORMATION IN THE SHORT GAMMA-RAY BURST RATE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leibler, C. N.; Berger, E.

2010-12-10

We present multi-band optical and near-infrared observations of 19 short {gamma}-ray burst (GRB) host galaxies, aimed at measuring their stellar masses and population ages. The goals of this study are to evaluate whether short GRBs track the stellar mass distribution of galaxies, to investigate the progenitor delay time distribution, and to explore any connection between long and short GRB progenitors. Using single stellar population models we infer masses of log(M{sub *}/M{sub sun}) {approx} 8.8-11.6, with a median of (log(M{sub *}/M{sub sun})) {approx} 10.1, and population ages of {tau}{sub *} {approx} 0.03-4.4 Gyr with a median of ({tau}{sub *}) {approx} 0.3more » Gyr. We further infer maximal masses of log(M{sub *}/M{sub sun}) {approx} 9.7-11.9 by assuming stellar population ages equal to the age of the universe at each host's redshift. Comparing the distribution of stellar masses to the general galaxy mass function, we find that short GRBs track the cosmic stellar mass distribution only if the late-type hosts generally have maximal masses. However, there is an apparent dearth of early-type hosts compared to the equal contribution of early- and late-type galaxies to the cosmic stellar mass budget. Similarly, the short GRB rate per unit old stellar mass appears to be elevated in the late-type hosts. These results suggest that stellar mass may not be the sole parameter controlling the short GRB rate, and raise the possibility of a two-component model with both mass and star formation playing a role (reminiscent of the case for Type Ia supernovae). If short GRBs in late-type galaxies indeed track the star formation activity, the resulting typical delay time is {approx}0.2 Gyr, while those in early-type hosts have a typical delay of {approx}3 Gyr. Using the same stellar population models, we fit the broadband photometry for 22 long GRB host galaxies in a similar redshift range and find that they have significantly lower masses and younger population ages, with

Distribution and mobility of exogenous copper as influenced by aging and components interactions in three Chinese soils.

PubMed

Shi, Hanzhi; Li, Qi; Chen, Wenli; Cai, Peng; Huang, Qiaoyun

2018-04-01

Copper contamination of soils is a global environmental problem. Soil components (organic matter, clay minerals, and microorganisms) and retention time can govern the adsorption, fixation, and distribution of copper. This study evaluated the interaction effects of soil components and aging on the distribution of exogenous copper. Three typical Chinese soils (Ultisol, Alfisol, and Histosol) were collected from Hunan, Henan, and Heilongjiang Provinces. Soils were incubated with rice straw (RS) and engineered bacteria (Pseudomonas putida X4/pIME) in the presence of exogenous copper for 12 months. Sequential extraction was employed to obtain the distribution of Cu species in soils, and the mobility factors of Cu were calculated. The relationships between soil properties and Cu fractions were analyzed with stepwise multiple linear regression. The results show that organic carbon plays a more important role in shaping the distribution of relatively mobile Cu, and iron oxides can be more critical in stabilizing Cu species in soils. Our results suggest that organic matter is the most important factor influencing copper partitioning in Ultisols, while iron oxides are more significant in Alfisols. The mobility of exogenous Cu in soils depends largely on organic carbon, amorphous Fe, and aging. The introduction of both rice straw and rice straw + engineered bacteria enhanced the stabilization of Cu in all the three soils during aging process. The introduction of bacteria could reduce copper mobility, which was indicated by the lowest mobility factors of Cu for the treatment with bacteria in Black, Red, and Cinnamon soils at the first 4, 8, and 8 months, respectively. Different measures should be taken into account regarding the content of organic matter and iron oxides depending on soil types for the risk assessment and remediation of Cu-contaminated soils.

Mean age distribution of inorganic soil-nitrogen

NASA Astrophysics Data System (ADS)

Woo, Dong K.; Kumar, Praveen

2016-07-01

Excess reactive nitrogen in soils of intensively managed landscapes causes adverse environmental impact, and continues to remain a global concern. Many novel strategies have been developed to provide better management practices and, yet, the problem remains unresolved. The objective of this study is to develop a model to characterize the "age" of inorganic soil-nitrogen (nitrate, and ammonia/ammonium). We use the general theory of age, which provides an assessment of the time elapsed since inorganic nitrogen has been introduced into the soil system. We analyze a corn-corn-soybean rotation, common in the Midwest United States, as an example application. We observe two counter-intuitive results: (1) the mean nitrogen age in the topsoil layer is relatively high; and (2) mean nitrogen age is lower under soybean cultivation compared to corn although no fertilizer is applied for soybean cultivation. The first result can be explained by cation-exchange of ammonium that retards the leaching of nitrogen, resulting in an increase in the mean nitrogen age near the soil surface. The second result arises because the soybean utilizes the nitrogen fertilizer left from the previous year, thereby removing the older nitrogen and reducing mean nitrogen age. Estimating the mean nitrogen age can thus serve as an important tool to disentangle complex nitrogen dynamics by providing a nuanced characterization of the time scales of soil-nitrogen transformation and transport processes.

The time of the insult/triggering event in Legg-Calvé-Perthes' disease determined by incubation period modeling and the age distribution of children with Perthes'.

PubMed

Loder, Randall T; Browne, Richard H; Millis, Andrew; Kim, Wook-Cheol; Shah, Hitesh; Cosgrove, Aidan P; Wiig, Ola

2012-01-01

The time when the insult/triggering event occurs in Legg-Calvé-Perthes' (LCPD) is unknown. the purpose of this study was to determine, using the mathematical tool of incubation period modeling, the time of such event and the incubation period for LCPD. We reviewed 2,911 children with LCPD from 10 different centers around the world. They were divided into two groups: those from India (505 children, mean age 8.1 ± 2.3 years) and those from other than India (2,406 children, mean age 5.8 ± 2.2 years). A simple distribution with an excellent fit to the data was ln(y) = a + bx + cxln(x), where y is the proportion of children with LCPD at age of diagnosis x (r(2) = 0.994 for non-Indian and 0.959 for Indian children). The age of the triggering event was 1.32 years for non-Indian and 2.77 years for Indian children; the median incubation period was 4.30 years non-Indian and 5.33 years for Indian patients. Knowing the incubation period and age of triggering event narrows the number of potential etiologies in LCPD. this study does not support a prenatal triggering event as postulated in the past. similar incubation periods with different ages at diagnosis supports a common insult which occurs at different ages in different populations dependent upon local factors such as geographic location and ethnicity.

Age and distribution of an evergreen clonal shrub in the Coweeta basin: Rhododendron maximum L

Treesearch

Katherine J. Elliott; James M. Vose

2012-01-01

Rhododendron maximum L. is an evergreen, clonal shrub that forms a dominant sub-canopy layer and is a key species in southern Appalachian forests. We investigated the age and distribution of R. maximum across the Coweeta Basin, a 1626 ha watershed in western North Carolina. We selected 16 perennial, second-order streams and used a Global Positioning System to establish...

Requests and usage of epidural analgesia in grand-grand multiparous and similar-aged women with lesser parity: prospective observational study.

PubMed

Ioscovich, Alexander; Fadeev, Angelika; Rivilis, Alina; Elstein, Deborah

2011-11-01

Epidural analgesia in older and multiparous women has been associated with risks. The aim of this study was to compare epidural analgesia use for labor/delivery in grand-grand multiparous women (GGMP; ≥10 births) relative to that in similar-aged women with lesser parity. This was a prospective observational study of advanced age gravida. All laboring women in a six-month period admitted to a tertiary Israeli center were included if they were advanced age (≥36 years old) with one to two previous births (Low parity; n=128) or four to five previous births (Medium parity; n=181), and all GGMP (any age; n=187). Primary outcome was comparison of requests for and use of epidural analgesia for labor/delivery. There were no significant differences across parity groups in percent of gravida requesting or receiving epidural analgesia (46.5-59.4%). Time from admission to epidural administration (range mean times: 168-187 min) and from advent of epidural to delivery (range mean times: 155-160 min) were comparable across parity groups. Use of other analgesia (5.8-8%) was not significantly different. Requests for and use of epidural analgesia was comparable in older gravida and was not correlated with parity. Mean times from presentation to epidural administration, mean cervical dilatation at epidural initiation, and mean time from performing of epidural to delivery were comparable across groups.

A surface renewal model for unsteady-state mass transfer using the generalized Danckwerts age distribution function.

PubMed

Horvath, Isabelle R; Chatterjee, Siddharth G

2018-05-01

The recently derived steady-state generalized Danckwerts age distribution is extended to unsteady-state conditions. For three different wind speeds used by researchers on air-water heat exchange on the Heidelberg Aeolotron, calculations reveal that the distribution has a sharp peak during the initial moments, but flattens out and acquires a bell-shaped character with process time, with the time taken to attain a steady-state profile being a strong and inverse function of wind speed. With increasing wind speed, the age distribution narrows significantly, its skewness decreases and its peak becomes larger. The mean eddy renewal time increases linearly with process time initially but approaches a final steady-state value asymptotically, which decreases dramatically with increased wind speed. Using the distribution to analyse the transient absorption of a gas into a large body of liquid, assuming negligible gas-side mass-transfer resistance, estimates are made of the gas-absorption and dissolved-gas transfer coefficients for oxygen absorption in water at 25°C for the three different wind speeds. Under unsteady-state conditions, these two coefficients show an inverse behaviour, indicating a heightened accumulation of dissolved gas in the surface elements, especially during the initial moments of absorption. However, the two mass-transfer coefficients start merging together as the steady state is approached. Theoretical predictions of the steady-state mass-transfer coefficient or transfer velocity are in fair agreement (average absolute error of prediction = 18.1%) with some experimental measurements of the same for the nitrous oxide-water system at 20°C that were made in the Heidelberg Aeolotron.

Mapping stand-age distribution of Russian forests from satellite data

NASA Astrophysics Data System (ADS)

Chen, D.; Loboda, T. V.; Hall, A.; Channan, S.; Weber, C. Y.

2013-12-01

Russian boreal forest is a critical component of the global boreal biome as approximately two thirds of the boreal forest is located in Russia. Numerous studies have shown that wildfire and logging have led to extensive modifications of forest cover in the region since 2000. Forest disturbance and subsequent regrowth influences carbon and energy budgets and, in turn, affect climate. Several global and regional satellite-based data products have been developed from coarse (>100m) and moderate (10-100m) resolution imagery to monitor forest cover change over the past decade, record of forest cover change pre-dating year 2000 is very fragmented. Although by using stacks of Landsat images, some information regarding the past disturbances can be obtained, the quantity and locations of such stacks with sufficient number of images are extremely limited, especially in Eastern Siberia. This paper describes a modified method which is built upon previous work to hindcast the disturbance history and map stand-age distribution in the Russian boreal forest. Utilizing data from both Landsat and the Moderate Resolution Imaging Spectroradiometer (MODIS), a wall-to-wall map indicating the estimated age of forest in the Russian boreal forest is created. Our previous work has shown that disturbances can be mapped successfully up to 30 years in the past as the spectral signature of regrowing forests is statistically significantly different from that of mature forests. The presented algorithm ingests 55 multi-temporal stacks of Landsat imagery available over Russian forest before 2001 and processes through a standardized and semi-automated approach to extract training and validation data samples. Landsat data, dating back to 1984, are used to generate maps of forest disturbance using temporal shifts in Disturbance Index through the multi-temporal stack of imagery in selected locations. These maps are then used as reference data to train a decision tree classifier on 50 MODIS

On the probabilistic structure of water age: Probabilistic Water Age

DOE Office of Scientific and Technical Information (OSTI.GOV)

Porporato, Amilcare; Calabrese, Salvatore

We report the age distribution of water in hydrologic systems has received renewed interest recently, especially in relation to watershed response to rainfall inputs. The purpose of this contribution is first to draw attention to existing theories of age distributions in population dynamics, fluid mechanics and stochastic groundwater, and in particular to the McKendrick-von Foerster equation and its generalizations and solutions. A second and more important goal is to clarify that, when hydrologic fluxes are modeled by means of time-varying stochastic processes, the age distributions must themselves be treated as random functions. Once their probabilistic structure is obtained, it canmore » be used to characterize the variability of age distributions in real systems and thus help quantify the inherent uncertainty in the field determination of water age. Finally, we illustrate these concepts with reference to a stochastic storage model, which has been used as a minimalist model of soil moisture and streamflow dynamics.« less

On the probabilistic structure of water age: Probabilistic Water Age

DOE PAGES

Porporato, Amilcare; Calabrese, Salvatore

2015-04-23

We report the age distribution of water in hydrologic systems has received renewed interest recently, especially in relation to watershed response to rainfall inputs. The purpose of this contribution is first to draw attention to existing theories of age distributions in population dynamics, fluid mechanics and stochastic groundwater, and in particular to the McKendrick-von Foerster equation and its generalizations and solutions. A second and more important goal is to clarify that, when hydrologic fluxes are modeled by means of time-varying stochastic processes, the age distributions must themselves be treated as random functions. Once their probabilistic structure is obtained, it canmore » be used to characterize the variability of age distributions in real systems and thus help quantify the inherent uncertainty in the field determination of water age. Finally, we illustrate these concepts with reference to a stochastic storage model, which has been used as a minimalist model of soil moisture and streamflow dynamics.« less

Cervical HPV type-specific pre-vaccination prevalence and age distribution in Croatia.

PubMed

Sabol, Ivan; Milutin Gašperov, Nina; Matovina, Mihaela; Božinović, Ksenija; Grubišić, Goran; Fistonić, Ivan; Belci, Dragan; Alemany, Laia; Džebro, Sonja; Dominis, Mara; Šekerija, Mario; Tous, Sara; de Sanjosé, Silvia; Grce, Magdalena

2017-01-01

The main etiological factor of precancerous lesion and invasive cervical cancer are oncogenic human papillomaviruses types (HPVs). The objective of this study was to establish the distribution of the most common HPVs in different cervical lesions and cancer prior to the implementation of organized population-based cervical screening and HPV vaccination in Croatia. In this study, 4,432 cervical specimens, collected through a 16-year period, were tested for the presence of HPV-DNA by polymerase chain reaction (PCR) with three sets of broad-spectrum primers and type-specific primers for most common low-risk (LR) types (HPV-6, 11) and the most common high-risk (HR) types (HPV-16, 18, 31, 33, 45, 52, 58). Additional 35 archival formalin-fixed, paraffin embedded tissue of cervical cancer specimens were analyzed using LiPA25 assay. The highest age-specific HPV-prevalence was in the group 18-24 years, which decreased continuously with age (P<0.0001) regardless of the cytological diagnosis. The prevalence of HR-HPV types significantly increased (P<0.0001) with the severity of cervical lesions. HPV-16 was the most common type found with a prevalence (with or without another HPV-type) of 6.9% in normal cytology, 15.5% in atypical squamous cells of undetermined significance, 14.4% in low-grade squamous intraepithelial lesions, 33.3% in high-grade squamous intraepithelial lesions, and 60.9% in cervical cancer specimens (P<0.0001). This study provides comprehensive and extensive data on the distribution of the most common HPV types among Croatian women, which will enable to predict and to monitor the impact of HPV-vaccination and to design effective screening strategies in Croatia.

Vector optical fields with polarization distributions similar to electric and magnetic field lines.

PubMed

Pan, Yue; Li, Si-Min; Mao, Lei; Kong, Ling-Jun; Li, Yongnan; Tu, Chenghou; Wang, Pei; Wang, Hui-Tian

2013-07-01

We present, design and generate a new kind of vector optical fields with linear polarization distributions modeling to electric and magnetic field lines. The geometric configurations of "electric charges" and "magnetic charges" can engineer the spatial structure and symmetry of polarizations of vector optical field, providing additional degrees of freedom assisting in controlling the field symmetry at the focus and allowing engineering of the field distribution at the focus to the specific applications.

Gradients of microhabitat and crappie (Pomoxis spp.) distributions in reservoir coves

USGS Publications Warehouse

Kaczka, Levi J.; Miranda, Leandro E.

2013-01-01

Embayments are among the most widespread littoral habitats found in Mississippi flood-control reservoirs. These macrohabitats represent commonly used nursery zones for age-0 crappies, Pomoxis spp., despite barren and eroded shorelines formed over 60–70 years of annual water level fluctuations. We tested if embayments displayed microhabitat gradients linked to the effect of water level fluctuations on riparian vegetation and if these gradients were paralleled by gradients in age-0 crappie distribution. Habitat composition changed longitudinally along the embayments with the most pronounced gradient representing a shift from nonvegetated mudflats near the mouth of embayments to herbaceous material upstream. The degree of habitat change depended on the water level. Similarly, catch rates of crappies increased upstream toward the rear of embayments, differing among water levels and reservoirs, but the longitudinal pattern persisted. Our results indicate that habitat composition gradients occur in embayments of northwest Mississippi flood-control reservoirs and that these gradients may influence a similar gradient in age-0 crappie distribution. While the biotic interactions behind the gradients may be less clear, we speculate that water level is the main factor influencing the observed gradients in habitat composition and fish. Management to benefit age-0 crappies may involve habitat improvement along embayment shorelines and water level regimes that foster growth of herbaceous plants.

Geodesic regression on orientation distribution functions with its application to an aging study.

PubMed

Du, Jia; Goh, Alvina; Kushnarev, Sergey; Qiu, Anqi

2014-02-15

In this paper, we treat orientation distribution functions (ODFs) derived from high angular resolution diffusion imaging (HARDI) as elements of a Riemannian manifold and present a method for geodesic regression on this manifold. In order to find the optimal regression model, we pose this as a least-squares problem involving the sum-of-squared geodesic distances between observed ODFs and their model fitted data. We derive the appropriate gradient terms and employ gradient descent to find the minimizer of this least-squares optimization problem. In addition, we show how to perform statistical testing for determining the significance of the relationship between the manifold-valued regressors and the real-valued regressands. Experiments on both synthetic and real human data are presented. In particular, we examine aging effects on HARDI via geodesic regression of ODFs in normal adults aged 22 years old and above. © 2013 Elsevier Inc. All rights reserved.

Gender- and Age-Specific REE and REE/FFM Distributions in Healthy Chinese Adults

PubMed Central

Cheng, Yu; Yang, Xue; Na, Li-Xin; Li, Ying; Sun, Chang-Hao

2016-01-01

Basic data on the resting energy expenditure (REE) of healthy populations are currently rare, especially for developing countries. The aims of the present study were to describe gender- and age-specific REE distributions and to evaluate the relationships among glycolipid metabolism, eating behaviors, and REE in healthy Chinese adults. This cross-sectional survey included 540 subjects (343 women and 197 men, 20–79 years old). REE was measured by indirect calorimetry and expressed as kcal/day/kg total body weight. The data were presented as the means and percentiles for REE and the REE to fat-free mass (FFM) ratio; differences were described by gender and age. Partial correlation analysis was used to analyze the correlations between REE, tertiles of REE/FFM, and glycolipid metabolism and eating behaviors. In this study, we confirmed a decline in REE with age in women (p = 0.000) and men (p = 0.000), and we found that men have a higher REE (p = 0.000) and lower REE/FFM (p = 0.021) than women. Furthermore, we observed no associations among glycolipid metabolism, eating behaviors, and REE in healthy Chinese adults. In conclusion, the results presented here may be useful to clinicians and nutritionists for comparing healthy and ill subjects and identifying changes in REE that are related to aging, malnutrition, and chronic diseases. PMID:27598192

Gender- and Age-Specific REE and REE/FFM Distributions in Healthy Chinese Adults.

PubMed

Cheng, Yu; Yang, Xue; Na, Li-Xin; Li, Ying; Sun, Chang-Hao

2016-09-01

Basic data on the resting energy expenditure (REE) of healthy populations are currently rare, especially for developing countries. The aims of the present study were to describe gender- and age-specific REE distributions and to evaluate the relationships among glycolipid metabolism, eating behaviors, and REE in healthy Chinese adults. This cross-sectional survey included 540 subjects (343 women and 197 men, 20-79 years old). REE was measured by indirect calorimetry and expressed as kcal/day/kg total body weight. The data were presented as the means and percentiles for REE and the REE to fat-free mass (FFM) ratio; differences were described by gender and age. Partial correlation analysis was used to analyze the correlations between REE, tertiles of REE/FFM, and glycolipid metabolism and eating behaviors. In this study, we confirmed a decline in REE with age in women (p = 0.000) and men (p = 0.000), and we found that men have a higher REE (p = 0.000) and lower REE/FFM (p = 0.021) than women. Furthermore, we observed no associations among glycolipid metabolism, eating behaviors, and REE in healthy Chinese adults. In conclusion, the results presented here may be useful to clinicians and nutritionists for comparing healthy and ill subjects and identifying changes in REE that are related to aging, malnutrition, and chronic diseases.

The macro determinants of health expenditure in the United States and Canada: assessing the impact of income, age distribution and time.

PubMed

Di Matteo, Livio

2005-01-01

This paper examines the determinants of real per capita health expenditures in order to assess the impact of age distribution, income and time using American state-level data for the period 1980-1998 and Canadian province-level data for the period 1975-2000. Ageing population distributions and income explain a relatively small portion of health expenditures when the impact of time effects, which is a partial proxy for technological change, is controlled for. However, the impact of age is of more concern given that cost increases are concentrated in the last few years of life and there may be cohort effects as the "Baby-Boom" generation ages. There is an urgent need to better understand the exact mechanisms driving health expenditure increases given that time accounts for approximately two-thirds of health expenditure increases and that its effect is non-linear.

A Test of the Exponential Distribution for Stand Structure Definition in Uneven-aged Loblolly-Shortleaf Pine Stands

Treesearch

Paul A. Murphy; Robert M. Farrar

1981-01-01

In this study, 588 before-cut and 381 after-cut diameter distributions of uneven-aged loblolly-shortleaf pinestands were fitted to two different forms of the exponential probability density function. The left truncated and doubly truncated forms of the exponential were used.

Sex differences in the spatial distribution of bone in relation to incident hip fracture: Findings from the AGES-Reykjavik study.

PubMed

Marques, Elisa A; Carballido-Gamio, Julio; Gudnason, Vilmundur; Sigurdsson, Gunnar; Sigurdsson, Sigurdur; Aspelund, Thor; Siggeirsdottir, Kristin; Launer, Lenore; Eiriksdottir, Gudny; Lang, Thomas; Harris, Tamara B

2018-05-16

In this case-cohort study, we used data-driven computational anatomy approaches to assess within and between sex spatial differences in proximal femoral bone characteristics in relation to incident hip fracture. One hundred male and 234 female incident hip fracture cases, and 1047 randomly selected noncase subcohort participants (562 female) were chosen from the population-based AGES-Reykjavik study (mean age of 77 years). The baseline -i.e. before hip fracture- hip quantitative computed tomography scans of these subjects were analyzed using voxel-based morphometry, tensor-based morphometry, and surface-based statistical parametric mapping to assess the spatial distribution of volumetric bone mineral density (vBMD), internal structure, and cortical bone properties (thickness, vBMD and trabecular vBMD adjacent to the endosteal surface) of the proximal femur, respectively, in relation to incident hip fracture. Results showed that in both men and women: 1) the superior aspect of the femoral neck and the trochanteric region (except for cortical bone thickness) were consistently identified as being associated with incident hip fracture, and 2) differences in bone properties between noncases and incident hip fracture cases followed similar trends, were located at compatible regions, and manifested heterogeneity in the spatial distribution of their magnitude with focal regions showing larger differences. With respect to sex differences, most of the regions with a significant interaction between fracture group and sex showed: 1) differences of greater magnitude in men between noncases and incident hip fracture cases with different spatial distributions for all bone properties with the exception of cortical bone thickness, and 2) that while most of these regions showed better bone quality in male cases than in female cases, female cases showed higher vBMD in the principal compressive group and higher endotrabecular vBMD at several regions including the anterior, posterior

Fractography evolution in accelerated aging of UHMWPE after gamma irradiation in air.

PubMed

Medel, F; Gómez-Barrena, E; García-Alvarez, F; Ríos, R; Gracia-Villa, L; Puértolas, J A

2004-01-01

We studied the fracture surface evolution of ultra high molecular weight polyethylene (UHMWPE) specimens, manufactured from GUR 1050 compression moulded sheets, after gamma sterilisation in air followed by different aging times after thermal treatment at 120 degrees C. Degradation profiles were obtained by FTIR and DSC measurements after 0, 7, 14, 24 and 36h aging. We observed by SEM the morphology patterns at these aging times, in surface fractographies after uniaxial tensile test of standardised samples. The results pointed out clear differences between short and long aging times. At shorter times, 7h, the behaviour was similar to non-degraded UHMWPE, exhibiting ductile behaviour. At longer times, 24-36h, this thermal protocol provided a highly degraded zone in the subsurface, similar to the white band found after gamma irradiation in air followed by natural aging, although closer to the surface, at 150-200mum. The microstructure of this oxidation zone, similarly found in gamma irradiated samples shelf-aged for 6-7 years, although with different distribution of microvoids, was formed by fibrils, associated with embrittlement of the oxidised UHMWPE. In addition, the evolution of the oxidation index, the enthalpy content, the mechanical parameters, and the depth of the oxidation front deduced from the fractographies versus aging time showed that a changing behaviour in the degradation rate appeared at intermediate aging times.

Causal relations and feature similarity in children's inductive reasoning.

PubMed

Hayes, Brett K; Thompson, Susan P

2007-08-01

Four experiments examined the development of property induction on the basis of causal relations. In the first 2 studies, 5-year-olds, 8-year-olds, and adults were presented with triads in which a target instance was equally similar to 2 inductive bases but shared a causal antecedent feature with 1 of them. All 3 age groups used causal relations as a basis for property induction, although the proportion of causal inferences increased with age. Subsequent experiments pitted causal relations against featural similarity in induction. It was found that adults and 8-year-olds, but not 5-year-olds, preferred shared causal relations over strong featural similarity as a basis for induction. The implications for models of inductive reasoning and development are discussed.

Bimodal collagen fibril diameter distributions direct age-related variations in tendon resilience and resistance to rupture

PubMed Central

Holmes, D. F.; Lu, Y.; Purslow, P. P.; Kadler, K. E.; Bechet, D.; Wess, T. J.

2012-01-01

Scaling relationships have been formulated to investigate the influence of collagen fibril diameter (D) on age-related variations in the strain energy density of tendon. Transmission electron microscopy was used to quantify D in tail tendon from 1.7- to 35.3-mo-old (C57BL/6) male mice. Frequency histograms of D for all age groups were modeled as two normally distributed subpopulations with smaller (DD1) and larger (DD2) mean Ds, respectively. Both DD1 and DD2 increase from 1.6 to 4.0 mo but decrease thereafter. From tensile tests to rupture, two strain energy densities were calculated: 1) uE [from initial loading until the yield stress (σY)], which contributes primarily to tendon resilience, and 2) uF [from σY through the maximum stress (σU) until rupture], which relates primarily to resistance of the tendons to rupture. As measured by the normalized strain energy densities uE/σY and uF/σU, both the resilience and resistance to rupture increase with increasing age and peak at 23.0 and 4.0 mo, respectively, before decreasing thereafter. Multiple regression analysis reveals that increases in uE/σY (resilience energy) are associated with decreases in DD1 and increases in DD2, whereas uF/σU (rupture energy) is associated with increases in DD1 alone. These findings support a model where age-related variations in tendon resilience and resistance to rupture can be directed by subtle changes in the bimodal distribution of Ds. PMID:22837169

Serum starvation of ARPE-19 changes the cellular distribution of cholesterol and Fibulin3 in patterns reminiscent of age-related macular degeneration.

PubMed

Rajapakse, Dinusha; Peterson, Katherine; Mishra, Sanghamitra; Wistow, Graeme

2017-12-15

Retinal pigment epithelium (RPE) has been implicated as key source of cholesterol-rich deposits at Bruch's membrane (BrM) and in drusen in aging human eye. We have shown that serum-deprivation of confluent RPE cells is associated with upregulation of cholesterol synthesis and accumulation of unesterified cholesterol (UC). Here we investigate the cellular processes involved in this response. We compared the distribution and localization of UC and esterified cholesterol (EC); the age-related macular degeneration (AMD) associated EFEMP1/Fibulin3 (Fib3); and levels of acyl-coenzyme A (CoA): cholesterol acyltransferases (ACAT) ACAT1, ACAT2 and Apolipoprotein B (ApoB) in ARPE-19 cells cultured in serum-supplemented and serum-free media. The results were compared with distributions of these lipids and proteins in human donor eyes with AMD. Serum deprivation of ARPE-19 was associated with increased formation of FM dye-positive membrane vesicles, many of which co-labeled for UC. Additionally, UC colocalized with Fib3 in distinct granules. By day 5, serum-deprived cells grown on transwells secreted Fib3 basally into the matrix. While mRNA and protein levels of ACTA1 were constant over several days of serum-deprivation, ACAT2 levels increased significantly after serum-deprivation, suggesting increased formation of EC. The lower levels of intracellular EC observed under serum-deprivation were associated with increased formation and secretion of ApoB. The responses to serum-deprivation in RPE-derived cells: accumulation and secretion of lipids, lipoproteins, and Fib3 are very similar to patterns seen in human donor eyes with AMD and suggest that this model mimics processes relevant to disease progression. Published by Elsevier Inc.

A residual stress study in similar and dissimilar welds

DOE PAGES

Eisazadeh, Hamid; Goldak, John A.; Aidun, Daryush K.; ...

2016-04-01

Residual strain distributions in similar and dissimilar welds were measured using neutron diffraction (ND) method. Then, using three strain components, three-dimensional stress states were calculated. The results were used to determine the effect of the martensitic phase transformation and material properties on residual stress (RS) distribution. It was observed that smaller longitudinal RS was induced in the low carbon steel side of dissimilar weld when compared to its similar weld. Also, it was found that the transverse RS near and within the weld zone (WZ) in dissimilar weld exhibited a distinctive trend, with tensile mode reaching the yield strength ofmore » the base metal (BM). In order to characterize the WZ in dissimilar weld, we deployed optical microscopy, hardness, and energy dispersive X-ray spectroscopy (EDAX). This study not only provides further insight into the RS state in similar and dissimilar welds; it also delivers important consequences of phase transformation in the latter case.« less

A surface renewal model for unsteady-state mass transfer using the generalized Danckwerts age distribution function

PubMed Central

Horvath, Isabelle R.

2018-01-01

The recently derived steady-state generalized Danckwerts age distribution is extended to unsteady-state conditions. For three different wind speeds used by researchers on air–water heat exchange on the Heidelberg Aeolotron, calculations reveal that the distribution has a sharp peak during the initial moments, but flattens out and acquires a bell-shaped character with process time, with the time taken to attain a steady-state profile being a strong and inverse function of wind speed. With increasing wind speed, the age distribution narrows significantly, its skewness decreases and its peak becomes larger. The mean eddy renewal time increases linearly with process time initially but approaches a final steady-state value asymptotically, which decreases dramatically with increased wind speed. Using the distribution to analyse the transient absorption of a gas into a large body of liquid, assuming negligible gas-side mass-transfer resistance, estimates are made of the gas-absorption and dissolved-gas transfer coefficients for oxygen absorption in water at 25°C for the three different wind speeds. Under unsteady-state conditions, these two coefficients show an inverse behaviour, indicating a heightened accumulation of dissolved gas in the surface elements, especially during the initial moments of absorption. However, the two mass-transfer coefficients start merging together as the steady state is approached. Theoretical predictions of the steady-state mass-transfer coefficient or transfer velocity are in fair agreement (average absolute error of prediction = 18.1%) with some experimental measurements of the same for the nitrous oxide–water system at 20°C that were made in the Heidelberg Aeolotron. PMID:29892429

Relative controls of external and internal variability on time-variable transit time distributions, and the importance of StorAge Selection function approaches

NASA Astrophysics Data System (ADS)

Kim, M.; Pangle, L. A.; Cardoso, C.; Lora, M.; Meira, A.; Volkmann, T. H. M.; Wang, Y.; Harman, C. J.; Troch, P. A. A.

2015-12-01

Transit time distributions (TTDs) are an efficient way of characterizing complex transport dynamics of a hydrologic system. Time-invariant TTD has been studied extensively, but TTDs are time-varying under unsteady hydrologic systems due to both external variability (e.g., time-variability in fluxes), and internal variability (e.g., time-varying flow pathways). The use of "flow-weighted time" has been suggested to account for the effect of external variability on TTDs, but neglects the role of internal variability. Recently, to account both types of variability, StorAge Selection (SAS) function approaches were developed. One of these approaches enables the transport characteristics of a system - how the different aged water in the storage is sampled by the outflow - to be parameterized by time-variable probability distribution called the rank SAS (rSAS) function, and uses it directly to determine the time-variable TTDs resulting from a given timeseries of fluxes in and out of a system. Unlike TTDs, the form of the rSAS function varies only due to changes in flow pathways, but is not affected by the timing of fluxes alone. However, the relation between physical mechanisms and the time-varying rSAS functions are not well understood. In this study, relative effects of internal and external variability on the TTDs are examined using observations from a homogeneously packed 1 m3 sloping soil lysimeter. The observations suggest the importance of internal variability on TTDs, and reinforce the need to account for this variability using time-variable rSAS functions. Furthermore, the relative usefulness of two other formulations of SAS functions and the mortality rate (which plays a similar role to SAS functions in the McKendrick-von Foerster model of age-structured population dynamics) are also discussed. Finally, numerical modeling is used to explore the role of internal and external variability for hydrologic systems with diverse geomorphic and climate characteristics

Despite differences in cytosolic calcium regulation, lidocaine toxicity is similar in adult and neonatal rat dorsal root ganglia in vitro.

PubMed

Doan, Lisa V; Eydlin, Olga; Piskoun, Boris; Kline, Richard P; Recio-Pinto, Esperanza; Rosenberg, Andrew D; Blanck, Thomas J J; Xu, Fang

2014-01-01

Neuraxial local anesthetics may have neurological complications thought to be due to neurotoxicity. A primary site of action of local anesthetics is the dorsal root ganglia (DRG) neuron. Physiologic differences have been noted between young and adult DRG neurons; hence, the authors examined whether there were any differences in lidocaine-induced changes in calcium and lidocaine toxicity in neonatal and adult rat DRG neurons. DRG neurons were cultured from postnatal day 7 (P7) and adult rats. Lidocaine-induced changes in cytosolic calcium were examined with the calcium indicator Fluo-4. Cells were incubated with varying concentrations of lidocaine and examined for viability using calcein AM and ethidium homodimer-1 staining. Live imaging of caspase-3/7 activation was performed after incubation with lidocaine. The mean KCl-induced calcium transient was greater in P7 neurons (P < 0.05), and lidocaine significantly inhibited KCl-induced calcium responses in both ages (P < 0.05). Frequency distribution histograms of KCl-evoked calcium increases were more heterogeneous in P7 than in adult neurons. With lidocaine, KCl-induced calcium transients in both ages became more homogeneous but remained different between the groups. Interestingly, cell viability was decreased by lidocaine in a dose-dependent manner similarly in both ages. Lidocaine treatment also activated caspase-3/7 in a dose- and time-dependent manner similarly in both ages. Despite physiological differences in P7 and adult DRG neurons, lidocaine cytotoxicity is similar in P7 and adult DRG neurons in vitro. Differences in lidocaine- and KCl-evoked calcium responses suggest the similarity in lidocaine cytotoxicity involves other actions in addition to lidocaine-evoked effects on cytosolic calcium responses.

Despite Differences in Cytosolic Calcium Regulation, Lidocaine Toxicity Is Similar in Adult and Neonatal Rat Dorsal Root Ganglia in Vitro

PubMed Central

Doan, Lisa V.; Eydlin, Olga; Piskoun, Boris; Kline, Richard P; Recio-Pinto, Esperanza; Rosenberg, Andrew D; Blanck, Thomas JJ; Xu, Fang

2013-01-01

Background Neuraxial local anesthetics may have neurological complications thought to be due to neurotoxicity. A primary site of action for local anesthetics is the dorsal root ganglia (DRG) neuron. Physiologic differences have been noted between young and adult DRG neurons; hence, we examined whether there were differences in lidocaine-induced changes in calcium and lidocaine toxicity in neonatal and adult rat DRG neurons. Methods DRG neurons were cultured from postnatal day 7 (P7) and adult rats. Lidocaine-induced changes in cytosolic calcium were examined with the calcium indicator Fluo-4. Cells were incubated with varying concentrations of lidocaine and examined for viability using calcein AM and ethidium homodimer-1 staining. Live imaging of caspase-3/7 activation was performed after incubation with lidocaine. Results The mean KCl-induced calcium transient was greater in P7 neurons (p < 0.05), and lidocaine significantly inhibited KCl-induced calcium responses in both ages (p < 0.05). Frequency distribution histograms of KCl-evoked calcium increases were more heterogeneous in P7 than in adult neurons. With lidocaine, KCl-induced calcium transients in both ages became more homogeneous but remained different between the groups. Interestingly cell viability was decreased by lidocaine in a dose-dependent manner similarly in both ages. Lidocaine treatment also activated caspase-3/7 in a dose- and time-dependent manner similarly in both ages. Conclusions Despite physiological differences in P7 and adult DRG neurons, lidocaine cytotoxicity is similar in P7 and adult DRG neurons in vitro. Differences in lidocaine- and KCl-evoked calcium responses suggest the similarity in lidocaine cytotoxicity involves other actions in addition to lidocaine-evoked effects on cytosolic calcium responses. PMID:23851347

Cost-effective age structure and geographical distribution of boreal forest reserves.

PubMed

Lundström, Johanna; Ohman, Karin; Perhans, Karin; Rönnqvist, Mikael; Gustafsson, Lena; Bugman, Harald

2011-02-01

1. Forest reserves are established to preserve biodiversity, and to maintain natural functions and processes. Today there is heightened focus on old-growth stages, with less attention given to early successional stages. The biodiversity potential of younger forests has been overlooked, and the cost-effectiveness of incorporating different age classes in reserve networks has not yet been studied.2. We performed a reserve selection analysis in boreal Sweden using the Swedish National Forest Inventory plots. Seventeen structural variables were used as biodiversity indicators, and the cost of protecting each plot as a reserve was assessed using the Heureka system. A goal programming approach was applied, which allowed inclusion of several objectives and avoided a situation in which common indicators affected the result more than rare ones. The model was limited either by budget or area.3. All biodiversity indicators were found in all age classes, with more than half having the highest values in ages ≥ 100 years. Several large-tree indicators and all deadwood indicators had higher values in forests 0-14 years than in forests 15-69 years.4. It was most cost-effective to protect a large proportion of young forests since they generally have a lower net present value compared to older forests, but still contain structures of importance for biodiversity. However, it was more area-effective to protect a large proportion of old forests since they have a higher biodiversity potential per area.5. The geographical distribution of reserves selected with the budget-constrained model was strongly biassed towards the north-western section of boreal Sweden, with a large proportion of young forest, whereas the area-constrained model focussed on the south-eastern section, with dominance by the oldest age class.6.Synthesis and applications. We show that young forests with large amounts of structures important to biodiversity such as dead wood and remnant trees are cheap and cost

Cost-effective age structure and geographical distribution of boreal forest reserves

PubMed Central

Lundström, Johanna; Öhman, Karin; Perhans, Karin; Rönnqvist, Mikael; Gustafsson, Lena; Bugman, Harald

2011-01-01

1. Forest reserves are established to preserve biodiversity, and to maintain natural functions and processes. Today there is heightened focus on old-growth stages, with less attention given to early successional stages. The biodiversity potential of younger forests has been overlooked, and the cost-effectiveness of incorporating different age classes in reserve networks has not yet been studied. 2. We performed a reserve selection analysis in boreal Sweden using the Swedish National Forest Inventory plots. Seventeen structural variables were used as biodiversity indicators, and the cost of protecting each plot as a reserve was assessed using the Heureka system. A goal programming approach was applied, which allowed inclusion of several objectives and avoided a situation in which common indicators affected the result more than rare ones. The model was limited either by budget or area. 3. All biodiversity indicators were found in all age classes, with more than half having the highest values in ages ≥ 100 years. Several large-tree indicators and all deadwood indicators had higher values in forests 0–14 years than in forests 15–69 years. 4. It was most cost-effective to protect a large proportion of young forests since they generally have a lower net present value compared to older forests, but still contain structures of importance for biodiversity. However, it was more area-effective to protect a large proportion of old forests since they have a higher biodiversity potential per area. 5. The geographical distribution of reserves selected with the budget-constrained model was strongly biassed towards the north-western section of boreal Sweden, with a large proportion of young forest, whereas the area-constrained model focussed on the south-eastern section, with dominance by the oldest age class. 6. Synthesis and applications. We show that young forests with large amounts of structures important to biodiversity such as dead wood and remnant trees are cheap and

Social representations and normative beliefs of aging.

PubMed

Torres, Tatiana de Lucena; Camargo, Brigido Vizeu; Boulsfield, Andréa Barbará; Silva, Antônia Oliveira

2015-12-01

This study adopted the theory of social representations as a theoretical framework in order to characterize similarities and differences in social representations and normative beliefs of aging for different age groups. The 638 participants responded to self-administered questionnaire and were equally distributed by sex and age. The results show that aging is characterized by positive stereotypes (knowledge and experience); however, retirement is linked to aging, but in a negative way, particularly for men, involving illness, loneliness and disability. When age was considered, it was verified that the connections with the representational elements became more complex for older groups, showing social representation functionality, largely for the elderly. Adulthood seems to be preferred and old age is disliked. There were divergences related to the perception of the beginning of life phases, especially that of old age. Work was characterized as the opposite of aging, and it revealed the need for actions intended for the elderly and retired workers, with post-retirement projects. In addition, it suggests investment in public policies that encourage intergenerational contact, with efforts to reduce intolerance and discrimination based on age of people.

An analysis of the growth based on the size and age distributions of the hawksbill sea turtle inhabiting Cuban waters.

PubMed

Kobayashi, M

2000-11-01

The first costal scute (C 1) collected from 2, 749 hawksbill turtle (Eretmochelys imbricata) captured in Cuban waters in 1993 and 1994 were analyzed to determine their body size and age distributions. The C 1 width (C 1 W) was converted to the straight carapace length (SCL) using a formula, SCL = 4.3527 (C 1 W)0.8484, to examine its body size distribution. The SCL ranged from 51.3 to 96.1 cm with 68.8 cm of mean and 68.6 cm of median. Ages of captured turtles estimated from the C 1 surface patterns were ranged from 3.3 to 61.5 years old with 15.8 years of mean and 14.5 years of median. A growth function of van Bertalanffy, M(t) = A(1-Be-kt), was applied to determine the relationship between the age and body size (SCL). A formula, SCL = 80.4(1 -0.663e-0.118(Age)), was derived and indicated a slowdown in the growth after about 14 years old. The maturation age and the rate of sexually matured Cuban hawksbill turtles were also discussed based on these results.

The changes of stage distribution of seminiferous epithelium cycle and its correlations with Leydig cell stereological parameters in aging men.

PubMed

Huang, Rui; Zhu, Wei-Jie; Li, Jing; Gu, Yi-Qun

2014-12-01

To evaluate the changes of stage distribution of seminiferous epithelium cycle and its correlations with Leydig cell stereological parameters in aging men. Point counting method was used to analyze the stereological parameters of Leydig cells. The stage number of seminiferous epithelium cycle was calculated in the same testicular tissue samples which were used for Leydig cell stereological analysis. The aging group had shown more severe pathological changes as well as higher pathologic scores than the young group. Compared with the control group, the volume density (VV) and surface density (NA) of Leydig cells in the aging group were increased significantly. The stage number of seminiferous epithelium cycle in the aging group was decreased coincidently compared to the young group. Leydig cell Vv in the young group has a positive relationship with stages I, II, III, V and VI of seminiferous epithelium cycle, and Leydig cell NA and numerical density (NV) were positively related to stage IV. However, only the correlation between NV and stage II was found in the aging group. The stage number of seminiferous epithelium cycle was decreased in aging testes. Changes in the stage distribution in aging testes were related to the Leydig cell stereological parameters which presented as a sign of morphological changes. Copyright © 2014 Elsevier GmbH. All rights reserved.

Martian channels and valleys - Their characteristics, distribution, and age

NASA Technical Reports Server (NTRS)

Carr, M. H.; Clow, G. D.

1981-01-01

The distribution and ages of Martian channels and valleys, which are generally believed to have been cut by running water, are examined with particular emphasis on the small branching networks referred to as runoff channels or valley networks. Valleys at latitudes from 65 deg S to 65 deg N were surveyed on Viking images at resolutions between 125 and 300 m. Almost all of the valleys are found in the old cratered terrain, in areas characterized by high elevations, low albedos and low violet/red ratios. The networks are deduced to have formed early in the history of the planet, with a formation rate declining rapidly shortly after the decline of the cratering rate 3.9 billion years ago. Two types of outflow channels are distinguished: unconfined, in which broad swaths of terrain are scoured, and confined, in which flow is restricted to discrete channels. Both types start at local sources, and have formed episodically throughout Martian history. Fretted channels, found mainly in two latitude belts characterized by relatively rapid erosion along escarpments, are explained by the lateral enlargement of other channels by mass wasting.

Simple Kinematic Pathway Approach (KPA) to Catchment-scale Travel Time and Water Age Distributions

NASA Astrophysics Data System (ADS)

Soltani, S. S.; Cvetkovic, V.; Destouni, G.

2017-12-01

The distribution of catchment-scale water travel times is strongly influenced by morphological dispersion and is partitioned between hillslope and larger, regional scales. We explore whether hillslope travel times are predictable using a simple semi-analytical "kinematic pathway approach" (KPA) that accounts for dispersion on two levels of morphological and macro-dispersion. The study gives new insights to shallow (hillslope) and deep (regional) groundwater travel times by comparing numerical simulations of travel time distributions, referred to as "dynamic model", with corresponding KPA computations for three different real catchment case studies in Sweden. KPA uses basic structural and hydrological data to compute transient water travel time (forward mode) and age (backward mode) distributions at the catchment outlet. Longitudinal and morphological dispersion components are reflected in KPA computations by assuming an effective Peclet number and topographically driven pathway length distributions, respectively. Numerical simulations of advective travel times are obtained by means of particle tracking using the fully-integrated flow model MIKE SHE. The comparison of computed cumulative distribution functions of travel times shows significant influence of morphological dispersion and groundwater recharge rate on the compatibility of the "kinematic pathway" and "dynamic" models. Zones of high recharge rate in "dynamic" models are associated with topographically driven groundwater flow paths to adjacent discharge zones, e.g. rivers and lakes, through relatively shallow pathway compartments. These zones exhibit more compatible behavior between "dynamic" and "kinematic pathway" models than the zones of low recharge rate. Interestingly, the travel time distributions of hillslope compartments remain almost unchanged with increasing recharge rates in the "dynamic" models. This robust "dynamic" model behavior suggests that flow path lengths and travel times in shallow

Age distribution of emergency department presentations in Victoria.

PubMed

Freed, Gary L; Gafforini, Sarah; Carson, Norman

2015-04-01

To describe patterns of ED utilisation over time, by patient age group and triage classification. Secondary analysis of data from all patients presenting to EDs in Victoria utilising the Victorian Emergency Minimum Dataset (VEMD) for the years 2002-2013. The VEMD includes all hospitals in Victoria with 24 h EDs. The absolute number of presentations to EDs in Victoria has grown by over 52% in the last 11 years. The triage categories of highest urgency (1-3) grew by 89% whereas the categories of lowest urgency (4-5) grew by 33%. Over this period, the 5 year age band with the greatest number of ED presentations has consistently been, by far, children 0-4 years of age. This age group has seen an increase of 29% in ED presentations overall with a >55% increase in Triage 1-3, and an increase of 16% in triage 4-5. For all age groups, there has been little change in the number of triage category 4-5 presentations since 2007/2008. However, for triage categories 1-3, there have been consistent increases in presentations across all age groups. The age range with the greatest absolute number of ED presentations in Victoria is children 0-4 years of age. This finding is consistent over time and across all triage classifications. The age range with the second highest absolute number of ED presentations is comprised of those 20-24 years of age. This is in contrast to the frequent public attention placed on the volume of ED presentations by the elderly. © 2015 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

Glacial lakes in Austria - Distribution and formation since the Little Ice Age

NASA Astrophysics Data System (ADS)

Buckel, J.; Otto, J. C.; Prasicek, G.; Keuschnig, M.

2018-05-01

Glacial lakes constitute a substantial part of the legacy of vanishing mountain glaciation and act as water storage, sediment traps and sources of both natural hazards and leisure activities. For these reasons, they receive growing attention by scientists and society. However, while the evolution of glacial lakes has been studied intensively over timescales tied to remote sensing-based approaches, the longer-term perspective has been omitted due a lack of suitable data sources. We mapped and analyzed the spatial distribution of glacial lakes in the Austrian Alps. We trace the development of number and area of glacial lakes in the Austrian Alps since the Little Ice Age (LIA) based on a unique combination of a lake inventory and an extensive record of glacier retreat. We find that bedrock-dammed lakes are the dominant lake type in the inventory. Bedrock- and moraine-dammed lakes populate the highest landscape domains located in cirques and hanging valleys. We observe lakes embedded in glacial deposits at lower locations on average below 2000 m a.s.l. In general, the distribution of glacial lakes over elevation reflects glacier erosional and depositional dynamics rather than the distribution of total area. The rate of formation of new glacial lakes (number, area) has continuously accelerated over time with present rates showing an eight-fold increase since LIA. At the same time the total glacier area decreased by two-thirds. This development coincides with a long-term trend of rising temperatures and a significant stepping up of this trend within the last 20 years in the Austrian Alps.

Spatiotemporal distribution and population characteristicsof a nonnative lake trout population, with implications for suppression

USGS Publications Warehouse

Dux, A.M.; Guy, C.S.; Fredenberg, W.A.

2011-01-01

We evaluated the distribution and population characteristics of nonnative lake trout Salvelinus namaycush in Lake McDonald,Glacier National Park,Montana, to provide biological data in support of a potential suppression program. Using ultrasonic telemetry, we identified spatial and temporal distribution patterns by tracking 36 adult lake trout (1,137 relocations). Lake trout rarely occupied depths greater than 30 m and were commonly located in the upper hypolimnion directly below the metalimnion during thermal stratification. After breakdown of themetalimnion in the fall, lake trout primarily aggregated at two spawning sites. Lake trout population characteristics were similar to those of populations within the species' native range. However, lake trout in Lake McDonald exhibited lower total annual mortality (13.2%), latermaturity (age 12 formales, age 15 for females), lower body condition, and slower growth than are typically observed in the southern extent of their range. These results will be useful in determining where to target suppression activities (e.g., gillnetting, trap-netting, or electrofishing) and in evaluating responses to suppression efforts. Similar evaluations of lake trout distribution patterns and population characteristics are recommended to increase the likelihood that suppression programs will succeed. ?? American Fisheries Society 2011.

Aging in the natural world: comparative data reveal similar mortality patterns across primates.

PubMed

Bronikowski, Anne M; Altmann, Jeanne; Brockman, Diane K; Cords, Marina; Fedigan, Linda M; Pusey, Anne; Stoinski, Tara; Morris, William F; Strier, Karen B; Alberts, Susan C

2011-03-11

Human senescence patterns-late onset of mortality increase, slow mortality acceleration, and exceptional longevity-are often described as unique in the animal world. Using an individual-based data set from longitudinal studies of wild populations of seven primate species, we show that contrary to assumptions of human uniqueness, human senescence falls within the primate continuum of aging; the tendency for males to have shorter life spans and higher age-specific mortality than females throughout much of adulthood is a common feature in many, but not all, primates; and the aging profiles of primate species do not reflect phylogenetic position. These findings suggest that mortality patterns in primates are shaped by local selective forces rather than phylogenetic history.

SpolSimilaritySearch - A web tool to compare and search similarities between spoligotypes of Mycobacterium tuberculosis complex.

PubMed

Couvin, David; Zozio, Thierry; Rastogi, Nalin

2017-07-01

Spoligotyping is one of the most commonly used polymerase chain reaction (PCR)-based methods for identification and study of genetic diversity of Mycobacterium tuberculosis complex (MTBC). Despite its known limitations if used alone, the methodology is particularly useful when used in combination with other methods such as mycobacterial interspersed repetitive units - variable number of tandem DNA repeats (MIRU-VNTRs). At a worldwide scale, spoligotyping has allowed identification of information on 103,856 MTBC isolates (corresponding to 98049 clustered strains plus 5807 unique isolates from 169 countries of patient origin) contained within the SITVIT2 proprietary database of the Institut Pasteur de la Guadeloupe. The SpolSimilaritySearch web-tool described herein (available at: http://www.pasteur-guadeloupe.fr:8081/SpolSimilaritySearch) incorporates a similarity search algorithm allowing users to get a complete overview of similar spoligotype patterns (with information on presence or absence of 43 spacers) in the aforementioned worldwide database. This tool allows one to analyze spread and evolutionary patterns of MTBC by comparing similar spoligotype patterns, to distinguish between widespread, specific and/or confined patterns, as well as to pinpoint patterns with large deleted blocks, which play an intriguing role in the genetic epidemiology of M. tuberculosis. Finally, the SpolSimilaritySearch tool also provides with the country distribution patterns for each queried spoligotype. Copyright © 2017 Elsevier Ltd. All rights reserved.

Color-size Relations of Disc Galaxies with Similar Stellar Masses

NASA Astrophysics Data System (ADS)

Fu, W.; Chang, R. X.; Shen, S. Y.; Zhang, B.

2011-01-01

To investigate the correlations between colors and sizes of disc galaxies with similar stellar masses, a sample of 7959 local face-on disc galaxies is collected from the main galaxy sample of the Seventh Data Release of Sloan Digital Sky Survey (SDSS DR7). Our results show that, under the condition that the stellar masses of disc galaxies are similar, the relation between u-r and size is weak, while g-r, r-i and r-z colors decrease with disk size. This means that the color-size relations of disc galaxies with similar stellar masses do exist, i.e., the more extended disc galaxies with similar stellar masses tend to have bluer colors. An artificial sample is constructed to confirm that this correlation is not driven by the color-stellar mass relations and size-stellar mass relation of disc galaxies. Our results suggest that the mass distribution of disk galaxies may have an important influence on their stellar formation history, i.e., the galaxies with more extended mass distribution evolve more slowly.

Recognition memory is modulated by visual similarity.

PubMed

Yago, Elena; Ishai, Alumit

2006-06-01

We used event-related fMRI to test whether recognition memory depends on visual similarity between familiar prototypes and novel exemplars. Subjects memorized portraits, landscapes, and abstract compositions by six painters with a unique style, and later performed a memory recognition task. The prototypes were presented with new exemplars that were either visually similar or dissimilar. Behaviorally, novel, dissimilar items were detected faster and more accurately. We found activation in a distributed cortical network that included face- and object-selective regions in the visual cortex, where familiar prototypes evoked stronger responses than new exemplars; attention-related regions in parietal cortex, where responses elicited by new exemplars were reduced with decreased similarity to the prototypes; and the hippocampus and memory-related regions in parietal and prefrontal cortices, where stronger responses were evoked by the dissimilar exemplars. Our findings suggest that recognition memory is mediated by classification of novel exemplars as a match or a mismatch, based on their visual similarity to familiar prototypes.

Similarity Theory of Withdrawn Water Temperature Experiment

PubMed Central

2015-01-01

Selective withdrawal from a thermal stratified reservoir has been widely utilized in managing reservoir water withdrawal. Besides theoretical analysis and numerical simulation, model test was also necessary in studying the temperature of withdrawn water. However, information on the similarity theory of the withdrawn water temperature model remains lacking. Considering flow features of selective withdrawal, the similarity theory of the withdrawn water temperature model was analyzed theoretically based on the modification of governing equations, the Boussinesq approximation, and some simplifications. The similarity conditions between the model and the prototype were suggested. The conversion of withdrawn water temperature between the model and the prototype was proposed. Meanwhile, the fundamental theory of temperature distribution conversion was firstly proposed, which could significantly improve the experiment efficiency when the basic temperature of the model was different from the prototype. Based on the similarity theory, an experiment was performed on the withdrawn water temperature which was verified by numerical method. PMID:26065020

Similarity of Stream Width Distributions Across Headwater Systems

NASA Astrophysics Data System (ADS)

Allen, G. H.; Pavelsky, T.; Barefoot, E. A.; Tashie, A.; Butman, D. E.

2016-12-01

The morphology and abundance of streams control the rates of hydraulic and biogeochemical exchange between streams, groundwater, and the atmosphere. In large river systems, studies have used remote sensing to quantify river morphology, and have found that the relationship between river width and abundance is fractal, such that narrow rivers are proportionally more common than wider rivers. However, in headwater systems (stream order 1-3), where many biogeochemical reactions are most rapid, the relationship between stream width and abundance is unknown, reducing the certainty of biogeochemical flux estimates. To constrain this uncertainty, we surveyed two components of stream morphology (wetted stream width and length) in seven physiographically contrasting stream networks in Kings Creek in Konza Prarie, KS; Sagehen Creek in the N. Sierra Nevada Mtns., CA; Elder Creek in Angelo Coast Range Preserve, CA; Caribou Creek in the Caribou Poker Creek Research Watershed, AK; V40 Stream, NZ; Blue Duck Creek, NZ; Stony Creek in Duke Forest, NC. To assess temporal variations, we also surveyed stream geometry in a subcatchment of Stony Creek six times over a range of moderate streamflow conditions (discharge less than 90 percentile of gauge record). Here we show a strikingly consistent gamma statistical distribution of stream width in all surveys and a characteristic most abundant stream width of 32±7 cm independent of flow conditions or basin size. This consistency is remarkable given the substantial physical diversity among the studied catchments. We propose a model that invokes network topology theory and downstream hydraulic geometry to show that, as active drainage networks expand and contract in response to changes in streamflow, the most abundant stream width remains approximately static. This framework can be used to better extrapolate stream size and abundance from large rivers to small headwater streams, with significant impact on understanding of the hydraulic

Impact of Hydrologic and Micro-topographic Variabilities on Spatial Distribution of Mean Soil-Nitrogen Age

NASA Astrophysics Data System (ADS)

Woo, D.; Kumar, P.

2015-12-01

Excess reactive nitrogen in soils of intensively managed agricultural fields causes adverse environmental impact, and continues to remain a global concern. Many novel strategies have been developed to provide better management practices and, yet, the problem remains unresolved. The objective of this study is to develop a 3-dimensional model to characterize the spatially distributed ``age" of soil-nitrogen (nitrate and ammonia-ammonium) across a watershed. We use the general theory of age, which provides an assessment of the elapsed time since nitrogen is introduced into the soil system. Micro-topographic variability incorporates heterogeneity of nutrient transformations and transport associated with topographic depressions that form temporary ponds and produce prolonged periods of anoxic conditions, and roadside agricultural ditches that support rapid surface movement. This modeling effort utilizes 1-m Light Detection and Ranging (LiDAR) data. We find a significant correlation between hydrologic variability and mean nitrate age that enables assessment of preferential flow paths of nitrate leaching. The estimation of the mean nitrogen age can thus serve as a tool to disentangle complex nitrogen dynamics by providing the analysis of the time scales of soil-nitrogen transformation and transport processes without introducing additional parameters.

Shared Ageing Research Models (ShARM): a new facility to support ageing research.

PubMed

Duran, Adele L; Potter, Paul; Wells, Sara; Kirkwood, Tom; von Zglinicki, Thomas; McArdle, Anne; Scudamore, Cheryl; Meng, Qing-Jun; de Haan, Gerald; Corcoran, Anne; Bellantuono, Ilaria

2013-12-01

In order to manage the rise in life expectancy and the concomitant increased occurrence of age-related diseases, research into ageing has become a strategic priority. Mouse models are commonly utilised as they share high homology with humans and show many similar signs and diseases of ageing. However, the time and cost needed to rear aged cohorts can limit research opportunities. Sharing of resources can provide an ethically and economically superior framework to overcome some of these issues but requires dedicated infrastructure. Shared Ageing Research Models (ShARM) ( www.ShARMUK.org ) is a new, not-for-profit organisation funded by Wellcome Trust, open to all investigators. It collects, stores and distributes flash frozen tissues from aged murine models through its biorepository and provides a database of live ageing mouse colonies available in the UK and abroad. It also has an online environment (MICEspace) for collation and analysis of data from communal models and discussion boards on subjects such as the welfare of ageing animals and common endpoints for intervention studies. Since launching in July 2012, thanks to the generosity of researchers in UK and Europe, ShARM has collected more than 2,500 tissues and has in excess of 2,000 mice registered in live ageing colonies. By providing the appropriate support, ShARM has been able to bring together the knowledge and experience of investigators in the UK and Europe to maximise research outputs with little additional cost and minimising animal use in order to facilitate progress in ageing research.

The effect of growth hormone treatment on metabolic and cardiovascular risk factors is similar in preterm and term short, small for gestational age children.

PubMed

de Kort, Sandra W K; Willemsen, Ruben H; van der Kaay, Danielle C M; Hokken-Koelega, Anita C S

2009-07-01

We previously reported that short, small for gestational age (SGA) children who were born preterm have a lower body fat percentage and a higher blood pressure, insulin secretion and disposition index than short SGA children born at term. Whether preterm birth also influences these parameters during GH treatment is unknown. To compare blood pressure, insulin sensitivity, beta-cell function and body composition during 4 years of GH treatment, between preterm and term short SGA children. A total of 404 prepubertal non-GH-deficient short SGA children were divided into 143 preterm (< 36 weeks) and 261 term children. Height, blood pressure (n = 404), body composition measured by dual energy X-ray absorptiometry (DXA) (n = 138) and insulin sensitivity and beta-cell function calculated from a frequent sampling intravenous glucose tolerance test (FSIGT) with tolbutamide (n = 74) or from the homeostasis model assessment of insulin resistance (HOMA-IR) (n = 204). In preterm and term children, GH treatment resulted in a similar decrease in systolic and diastolic blood pressure, body fat percentage, limb fat/total fat ratio and insulin sensitivity, and a similar increase in insulin secretion and disposition index. Lean body mass (LBM) corrected for gender and height increased in term children and did not change in preterm children. Multiple regression analysis revealed that this difference in GH effect on LBM was not associated with gestational age. The effect of GH treatment on metabolic and cardiovascular risk factors is similar in preterm and term short, SGA children.

Structural transition in sputter-deposited amorphous germanium films by aging at ambient temperature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Okugawa, M.; Nakamura, R., E-mail: nakamura@mtr.osakafu-u.ac.jp; Numakura, H.

The structure of amorphous Ge (a-Ge) films prepared by sputter-deposition and the effects of aging at ambient temperature and pressure were studied by pair-distribution-function (PDF) analysis from electron scattering and molecular dynamics simulations. The PDFs of the as-deposited and aged samples for 3–13 months showed that the major peaks for Ge-Ge bonds decrease in intensity and broaden with aging for up to 7 months. In the PDFs of a-Ge of molecular dynamics simulation obtained by quenching liquid at different rates, the major peak intensities of a slowly cooled model are higher than those of a rapidly cooled model. Analyses onmore » short- and medium-range configurations show that the slowly cooled model includes a certain amount of medium-range ordered (MRO) clusters, while the rapidly cooled model includes liquid-like configurations rather than MRO clusters. The similarity between experimental and computational PDFs implies that as-deposited films are similar in structure to the slowly cooled model, whereas the fully aged films are similar to the rapidly cooled model. It is assumed that as they undergo room-temperature aging, the MRO clusters disintegrate and transform into liquid-like regions in the same matrix. This transition in local configurations is discussed in terms of instability and the non-equilibrium of nanoclusters produced by a vapor-deposition process.« less

Age Tracers and Residence Time in the Hudson River Estuary

NASA Astrophysics Data System (ADS)

Nadell, S. A.; Geyer, W. R.; Wang, T.

2016-02-01

The Hudson River is one of the most nutrient loaded rivers in the country, however phytoplankton bloom do not occur, possibly as a result of how quickly water moves though the Hudson River estuary. Slower water residence times may then allow for significant phytoplankton growth. Water age and residence time, which are compliments of one another under stead-state conditions, are important factors in determining where phytoplankton move and how long they spend within a favorable portion of the estuary. This research involved introducing a freshwater and saltwater age tracer into the Regional Ocean Modeling System (ROMS) for the Hudson River estuary domain to observe the distribution of ages within the spring-neap tidal cycle and across different river discharge rates. These discharge rates represented average (500 m3/s), relatively high (1000 m3/s), and relatively low (200 m3/s) river flow conditions for the Hudson River. Saltwater age followed a distribution similar to salinity, while freshwater age distribution mostly represented river transit time. Under steady state conditions, combined freshwater and saltwater age may be used to calculate a rough estimate of estuary residence time. The results show that the residence time of the full estuary appears to be at greater than the doubling time of phytoplankton for all discharge rates and by over five days for even the relatively high discharge case. This leads to the conclusion that other estuary factors, including light availability and salinity, may be more important for limiting phytoplankton growth than residence time.

Age, Gender, and Race-Based Coronary Artery Calcium Score Percentiles in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

PubMed

Pereira, Alexandre C; Gomez, Luz M; Bittencourt, Marcio Sommer; Staniak, Henrique Lane; Sharovsky, Rodolfo; Foppa, Murilo; Blaha, Michael J; Bensenor, Isabela M; Lotufo, Paulo A

2016-06-01

Coronary artery calcium (CAC) has been demonstrated to independently predict the risk of cardiovascular events and all-cause mortality, especially among White populations. Although the population distribution of CAC has been determined for several White populations, the distribution in ethnically admixed groups has not been well established. The CAC distribution, stratified for age, gender and race, is similar to the previously described distribution in the MESA study. The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) is a prospective cohort study designed to investigate subclinical cardiovascular disease in 6 different centers of Brazil. Similar to previous studies, individuals with self-reported coronary or cerebrovascular disease and those treated for diabetes mellitus were excluded from analysis. Percentiles of CAC distribution were estimated with nonparametric techniques. The analysis included 3616 individuals (54% female; mean age, 50 years). As expected, CAC prevalence and burden were steadily higher with increasing age, as well as increased in men and in White individuals. Our results revealed that for a given CAC score, the ELSA-derived CAC percentile would be lower in men compared with the Multi-Ethnic Study of Atherosclerosis (MESA) and would be higher in women compared with MESA. In our sample of the Brazilian population, we observed significant differences in CAC by sex, age, and race. Adjusted for age and sex, low-risk individuals from the Brazilian population present with significantly lower CAC prevalence and burden compared with other low-risk individuals from other worldwide populations. Using US-derived percentiles in Brazilian individuals may lead to overestimating relative CAC burden in men and underestimating relative CAC burden in women. © 2016 Wiley Periodicals, Inc.

Genus age, provincial area and the taxonomic structure of marine faunas.

PubMed

Harnik, Paul G; Jablonski, David; Krug, Andrew Z; Valentine, James W

2010-11-22

Species are unevenly distributed among genera within clades and regions, with most genera species-poor and few species-rich. At regional scales, this structure to taxonomic diversity is generated via speciation, extinction and geographical range dynamics. Here, we use a global database of extant marine bivalves to characterize the taxonomic structure of climate zones and provinces. Our analyses reveal a general, Zipf-Mandelbrot form to the distribution of species among genera, with faunas from similar climate zones exhibiting similar taxonomic structure. Provinces that contain older taxa and/or encompass larger areas are expected to be more species-rich. Although both median genus age and provincial area correlate with measures of taxonomic structure, these relationships are interdependent, nonlinear and driven primarily by contrasts between tropical and extra-tropical faunas. Provincial area and taxonomic structure are largely decoupled within climate zones. Counter to the expectation that genus age and species richness should positively covary, diverse and highly structured provincial faunas are dominated by young genera. The marked differences between tropical and temperate faunas suggest strong spatial variation in evolutionary rates and invasion frequencies. Such variation contradicts biogeographic models that scale taxonomic diversity to geographical area.

Genus age, provincial area and the taxonomic structure of marine faunas

PubMed Central

Harnik, Paul G.; Jablonski, David; Krug, Andrew Z.; Valentine, James W.

2010-01-01

Species are unevenly distributed among genera within clades and regions, with most genera species-poor and few species-rich. At regional scales, this structure to taxonomic diversity is generated via speciation, extinction and geographical range dynamics. Here, we use a global database of extant marine bivalves to characterize the taxonomic structure of climate zones and provinces. Our analyses reveal a general, Zipf–Mandelbrot form to the distribution of species among genera, with faunas from similar climate zones exhibiting similar taxonomic structure. Provinces that contain older taxa and/or encompass larger areas are expected to be more species-rich. Although both median genus age and provincial area correlate with measures of taxonomic structure, these relationships are interdependent, nonlinear and driven primarily by contrasts between tropical and extra-tropical faunas. Provincial area and taxonomic structure are largely decoupled within climate zones. Counter to the expectation that genus age and species richness should positively covary, diverse and highly structured provincial faunas are dominated by young genera. The marked differences between tropical and temperate faunas suggest strong spatial variation in evolutionary rates and invasion frequencies. Such variation contradicts biogeographic models that scale taxonomic diversity to geographical area. PMID:20534619

Student and Professor Similarity: Exploring the Effects of Gender and Relative Age

ERIC Educational Resources Information Center

Gehrt, Kenneth; Louie, Therese A.; Osland, Asbjorn

2015-01-01

The authors examined student responses to faculty traits. Earlier findings revealing a preference for male instructors were obtained before female faculty and students were prevalent on college campuses and may have reflected a male demographic similarity effect. It was hypothesized that students would more favorably evaluate faculty who were…

Gaze distribution analysis and saliency prediction across age groups.

PubMed

Krishna, Onkar; Helo, Andrea; Rämä, Pia; Aizawa, Kiyoharu

2018-01-01

Knowledge of the human visual system helps to develop better computational models of visual attention. State-of-the-art models have been developed to mimic the visual attention system of young adults that, however, largely ignore the variations that occur with age. In this paper, we investigated how visual scene processing changes with age and we propose an age-adapted framework that helps to develop a computational model that can predict saliency across different age groups. Our analysis uncovers how the explorativeness of an observer varies with age, how well saliency maps of an age group agree with fixation points of observers from the same or different age groups, and how age influences the center bias tendency. We analyzed the eye movement behavior of 82 observers belonging to four age groups while they explored visual scenes. Explorative- ness was quantified in terms of the entropy of a saliency map, and area under the curve (AUC) metrics was used to quantify the agreement analysis and the center bias tendency. Analysis results were used to develop age adapted saliency models. Our results suggest that the proposed age-adapted saliency model outperforms existing saliency models in predicting the regions of interest across age groups.

Similarities and differences in child development from birth to age 3 years by sex and across four countries: a cross-sectional, observational study.

PubMed

Ertem, Ilgi Ozturk; Krishnamurthy, Vibha; Mulaudzi, Mphelekedzeni C; Sguassero, Yanina; Balta, Hakan; Gulumser, Ozlem; Bilik, Burcu; Srinivasan, Roopa; Johnson, Benjamin; Gan, Geliang; Calvocoressi, Lisa; Shabanova, Veronika; Forsyth, Brian W C

2018-03-01

Knowledge about typical development is of fundamental importance for understanding and promoting child health and development. We aimed to ascertain when healthy children in four culturally and linguistically different countries attain developmental milestones and to identify similarities and differences across sexes and countries. In this cross-sectional, observational study, we recruited children aged 0-42 months and their caregivers between March 3, 2011, and May 18, 2015, at 22 health clinics in Argentina, India, South Africa, and Turkey. We obtained a healthy subsample, which excluded children with a low birthweight, perinatal complications, chronic illness, undernutrition, or anaemia, and children with missing health data. Using the Guide for Monitoring Child Development, caregivers described their child's development in seven domains: expressive and receptive language, gross and fine motor, play, relating, and self-help. Clinicians examining the children also completed a checklist about the child's health status. We used logit and probit regression models based on the lowest deviance information criterion to generate Bayesian point estimates and 95% credible intervals for the 50th percentile ages of attainment of 106 milestones. We assessed the significance of differences between sexes and countries using predefined criteria and regions of practical equivalence. Of 10 246 children recruited, 4949 children (48·3%) were included in the healthy subsample. For the 106 milestones assessed, the median age of attainment was equivalent for 102 (96%) milestones across sexes and 81 (76%) milestones across the four countries. Across countries, median ages of attainment were equivalent for all play milestones, 20 (77%) of 26 expressive language milestones, ten (67%) of 15 receptive language milestones, nine (82%) of 11 fine motor milestones, 14 (88%) of 16 gross motor milestones, and eight (73%) of 11 relating milestones. However, across the four countries the median

Emergent self-similarity of cluster coagulation

NASA Astrophysics Data System (ADS)

Pushkin, Dmtiri O.

A wide variety of nonequilibrium processes, such as coagulation of colloidal particles, aggregation of bacteria into colonies, coalescence of rain drops, bond formation between polymerization sites, and formation of planetesimals, fall under the rubric of cluster coagulation. We predict emergence of self-similar behavior in such systems when they are 'forced' by an external source of the smallest particles. The corresponding self-similar coagulation spectra prove to be power laws. Starting from the classical Smoluchowski coagulation equation, we identify the conditions required for emergence of self-similarity and show that the power-law exponent value for a particular coagulation mechanism depends on the homogeneity index of the corresponding coagulation kernel only. Next, we consider the current wave of mergers of large American banks as an 'unorthodox' application of coagulation theory. We predict that the bank size distribution has propensity to become a power law, and verify our prediction in a statistical study of the available economical data. We conclude this chapter by discussing economically significant phenomenon of capital condensation and predicting emergence of power-law distributions in other economical and social data. Finally, we turn to apparent semblance between cluster coagulation and turbulence and conclude that it is not accidental: both of these processes are instances of nonlinear cascades. This class of processes also includes river network formation models, certain force-chain models in granular mechanics, fragmentation due to collisional cascades, percolation, and growing random networks. We characterize a particular cascade by three indicies and show that the resulting power-law spectrum exponent depends on the indicies values only. The ensuing algebraic formula is remarkable for its simplicity.

Similar Antibody Levels in 3-Year-Old Children Vaccinated Against Measles, Mumps, and Rubella at the Age of 12 Months or 18 Months.

PubMed

Kontio, Mia; Palmu, Arto A; Syrjänen, Ritva K; Lahdenkari, Mika; Ruokokoski, Esa; Davidkin, Irja; Vaarala, Outi; Melin, Merit

2016-06-15

Measles-mumps-rubella (MMR) vaccinations have been offered to Finnish children at 14-18 months and 6 years of age. In May 2011, the recommended age for the first vaccine dose was lowered to 12 months because of the European measles epidemic. Fingertip capillary blood samples were collected from 3-year-old Finnish children vaccinated once with MMR vaccine at 11-19 months of age. The immunoglobulin G (IgG) antibodies to all 3 MMR antigens were measured with enzyme-linked immunosorbent assay. Neutralizing antibodies and the avidity of antibodies were measured for measles virus. From April through October 2013, 187 children were enrolled. Equally high proportions of the samples were seropositive for measles virus, mumps virus, or rubella virus antibodies, and there were no significant differences in the IgG antibody concentrations in children vaccinated at 11-13 months of age, compared with those vaccinated at 17-19 months of age. However, among children vaccinated at 11-13 months of age, boys had lower antibody concentrations than girls. Neutralizing measles virus antibody titers were above the threshold for protective immunity in all 78 samples analyzed. The measles virus antibody avidity indexes were high for all children. MMR induces similar antibody responses in 12-month-old children as compared to 18-month-old children, but in boys increasing age appears to improve the antibody responses. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

ANALYSIS OF AGED IN-HOME CARPETING TO DETERMINE THE DISTRIBUTION OF PESTICIDE RESIDUES BETWEEN DUST, CARPET, AND PAD COMPARTMENTS

EPA Science Inventory

This report presents results of a study to determine the distribution of pesticides, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) between dust and carpet components in aged carpeting. Carpeting in eight homes in the Research Triangle Area, which...

[Application of the data from China Total Diet Study to assess the distribution of lead exposure in different age-gender population groups].

PubMed

Li, Xiaowei; Liu, Qing; Liu, Liping; Wu, Yongning

2012-05-01

To assess the distribution of dietary lead exposure in different age-gender groups of Chinese residents by using the data from China Total Diet Study, and combining the new risk assessment and the PTWI withdrawn by JECFA. Methods Combining the lead concentrations of dietary samples with the food consumption data from China Total Diet Study in 2007 to obtain the distribution of dietary intake and dietary source of lead in different age-gender population groups. Dietary lead exposure of different age-gender population groups in China was in the range of 48.7 -116.7 microg/d. The status of higher lead exposure in younger age groups was not optimistic, as the mean and median margins of exposure (MOE) have been less than 1.0 (0.1 - 0.3). The main sources of dietary lead were cereals and vegetables, which covering 57% of total lead exposure. Lowering the dietary lead exposure of Chinese residents is necessary, especially of infants and children.

Preserved Discrimination Performance and Neural Processing during Crossmodal Attention in Aging

PubMed Central

Mishra, Jyoti; Gazzaley, Adam

2013-01-01

In a recent study in younger adults (19-29 year olds) we showed evidence that distributed audiovisual attention resulted in improved discrimination performance for audiovisual stimuli compared to focused visual attention. Here, we extend our findings to healthy older adults (60-90 year olds), showing that performance benefits of distributed audiovisual attention in this population match those of younger adults. Specifically, improved performance was revealed in faster response times for semantically congruent audiovisual stimuli during distributed relative to focused visual attention, without any differences in accuracy. For semantically incongruent stimuli, discrimination accuracy was significantly improved during distributed relative to focused attention. Furthermore, event-related neural processing showed intact crossmodal integration in higher performing older adults similar to younger adults. Thus, there was insufficient evidence to support an age-related deficit in crossmodal attention. PMID:24278464

Refractive, corneal and ocular residual astigmatism: distribution in a German population and age-dependency - the Gutenberg health study.

PubMed

Schuster, Alexander Karl-Georg; Pfeiffer, Norbert; Schulz, Andreas; Hoehn, René; Ponto, Katharina A; Wild, Philipp S; Blettner, Maria; Beutel, Manfred E; Lackner, Karl J; Münzel, Thomas; Mirshahi, Alireza

2017-12-01

Worldwide, the most frequent cause of visual impairment is uncorrected refractive error. This analysis focused on the distribution and associations of refractive, corneal and ocular residual astigmatism. As part of the Gutenberg Health study, a population-based cross-sectional study was conducted in the general population of Germany. A comprehensive ophthalmological examination including refraction, tonometry, and Scheimpflug imaging of the anterior cornea (Pachycam) was performed. In addition to the magnitude and type (with-the-rule, against-the-rule, oblique) of the refractive or corneal astigmatism, we calculated the vector components (J 0 , J 45 ) of both astigmatisms and calculated the ocular residual astigmatism. We performed multiple quantile regression analysis to evaluate the factors associated with refractive, corneal and ocular residual astigmatisms. A total of 13,558 subjects (49% female) with a mean age of 54.0 years (range 35-74 years) were included in this study. The prevalence of refractive astigmatism (>1.0D) was 13.0% in right eyes and 12.0% in left eyes, and 85% of these subjects wore spectacles. The distribution of refractive astigmatism showed a two-peak distribution with high astigmatism for with-the-rule and against-the-rule astigmatism. The associated factors were corneal curvature, age and sex for the different astigmatisms (p < 0.001). We analyzed the prevalence of different astigmatisms within a European population. We confirmed a shift with aging from with-the-rule to against-the-rule astigmatism to refractive and corneal astigmatism. Astigmatism has a large impact on visual perception; more than 85% of people with astigmatism over one diopter wore glasses for distance vision.

Average is Boring: How Similarity Kills a Meme's Success

NASA Astrophysics Data System (ADS)

Coscia, Michele

2014-09-01

Every day we are exposed to different ideas, or memes, competing with each other for our attention. Previous research explained popularity and persistence heterogeneity of memes by assuming them in competition for limited attention resources, distributed in a heterogeneous social network. Little has been said about what characteristics make a specific meme more likely to be successful. We propose a similarity-based explanation: memes with higher similarity to other memes have a significant disadvantage in their potential popularity. We employ a meme similarity measure based on semantic text analysis and computer vision to prove that a meme is more likely to be successful and to thrive if its characteristics make it unique. Our results show that indeed successful memes are located in the periphery of the meme similarity space and that our similarity measure is a promising predictor of a meme success.

Average is boring: how similarity kills a meme's success.

PubMed

Coscia, Michele

2014-09-26

Every day we are exposed to different ideas, or memes, competing with each other for our attention. Previous research explained popularity and persistence heterogeneity of memes by assuming them in competition for limited attention resources, distributed in a heterogeneous social network. Little has been said about what characteristics make a specific meme more likely to be successful. We propose a similarity-based explanation: memes with higher similarity to other memes have a significant disadvantage in their potential popularity. We employ a meme similarity measure based on semantic text analysis and computer vision to prove that a meme is more likely to be successful and to thrive if its characteristics make it unique. Our results show that indeed successful memes are located in the periphery of the meme similarity space and that our similarity measure is a promising predictor of a meme success.

A comparison of recharge rates in aquifers of the United States based on groundwater-age data

USGS Publications Warehouse

McMahon, P.B.; Plummer, Niel; Böhlke, J.K.; Shapiro, S.D.; Hinkle, S.R.

2011-01-01

An overview is presented of existing groundwater-age data and their implications for assessing rates and timescales of recharge in selected unconfined aquifer systems of the United States. Apparent age distributions in aquifers determined from chlorofluorocarbon, sulfur hexafluoride, tritium/helium-3, and radiocarbon measurements from 565 wells in 45 networks were used to calculate groundwater recharge rates. Timescales of recharge were defined by 1,873 distributed tritium measurements and 102 radiocarbon measurements from 27 well networks. Recharge rates ranged from < 10 to 1,200 mm/yr in selected aquifers on the basis of measured vertical age distributions and assuming exponential age gradients. On a regional basis, recharge rates based on tracers of young groundwater exhibited a significant inverse correlation with mean annual air temperature and a significant positive correlation with mean annual precipitation. Comparison of recharge derived from groundwater ages with recharge derived from stream base-flow evaluation showed similar overall patterns but substantial local differences. Results from this compilation demonstrate that age-based recharge estimates can provide useful insights into spatial and temporal variability in recharge at a national scale and factors controlling that variability. Local age-based recharge estimates provide empirical data and process information that are needed for testing and improving more spatially complete model-based methods.

Compressional Alfven Eigenmode Similarity Study

NASA Astrophysics Data System (ADS)

Heidbrink, W. W.; Fredrickson, E. D.; Gorelenkov, N. N.; Rhodes, T. L.

2004-11-01

NSTX and DIII-D are nearly ideal for Alfven eigenmode (AE) similarity experiments, having similar neutral beams, fast-ion to Alfven speed v_f/v_A, fast-ion pressure, and shape of the plasma, but with a factor of 2 difference in the major radius. Toroidicity-induced AE with ˜100 kHz frequencies were compared in an earlier study [1]; this paper focuses on higher frequency AE with f ˜ 1 MHz. Compressional AE (CAE) on NSTX have a polarization, dependence on the fast-ion distribution function, frequency scaling, and low-frequency limit that are qualitatively consistent with CAE theory [2]. Global AE (GAE) are also observed. On DIII-D, coherent modes in this frequency range are observed during low-field (0.6 T) similarity experiments. Experiments will compare the CAE stability limits on DIII-D with the NSTX stability limits, with the aim of determining if CAE will be excited by alphas in a reactor. Predicted differences in the frequency splitting Δ f between excited modes will also be used. \\vspace0.25em [1] W.W. Heidbrink, et al., Plasmas Phys. Control. Fusion 45, 983 (2003). [2] E.D. Fredrickson, et al., Princeton Plasma Physics Laboratory Report PPPL-3955 (2004).

Rotated sigmoid structures in managed uneven-aged northern hardwood stands: a look at the Burr Type III distribution

Treesearch

Jeffrey H. Gove; Mark J. Ducey; William B. Leak; Lianjun Zhang

2008-01-01

Stand structures from a combined density manipulation and even- to uneven-aged conversion experiment on the Bartlett Experimental Forest (New Hampshire, USA) were examined 25 years after initial treatment for rotated sigmoidal diameter distributions. A comparison was made on these stands between two probability density functions for fitting these residual structures:...

Geographical distribution of reference value of aging people's left ventricular end systolic diameter based on the support vector regression.

PubMed

Han, Xiao; Ge, Miao; Dong, Jie; Xue, Ranying; Wang, Zixuan; He, Jinwei

2014-09-01

The aim of this paper is to analyze the geographical distribution of reference value of aging people's left ventricular end systolic diameter (LVDs), and to provide a scientific basis for clinical examination. The study is focus on the relationship between reference value of left ventricular end systolic diameter of aging people and 14 geographical factors, selecting 2495 samples of left ventricular end systolic diameter (LVDs) of aging people in 71 units of China, in which including 1620 men and 875 women. By using the Moran's I index to make sure the relationship between the reference values and spatial geographical factors, extracting 5 geographical factors which have significant correlation with left ventricular end systolic diameter for building the support vector regression, detecting by the method of paired sample t test to make sure the consistency between predicted and measured values, finally, makes the distribution map through the disjunctive kriging interpolation method and fits the three-dimensional trend of normal reference value. It is found that the correlation between the extracted geographical factors and the reference value of left ventricular end systolic diameter is quite significant, the 5 indexes respectively are latitude, annual mean air temperature, annual mean relative humidity, annual precipitation amount, annual range of air temperature, the predicted values and the observed ones are in good conformity, there is no significant difference at 95% degree of confidence. The overall trend of predicted values increases from west to east, increases first and then decreases from north to south. If geographical values are obtained in one region, the reference value of left ventricular end systolic diameter of aging people in this region can be obtained by using the support vector regression model. It could be more scientific to formulate the different distributions on the basis of synthesizing the physiological and the geographical factors. -Use

Environmental niche models for riverine desert fishes and their similarity according to phylogeny and functionality

USGS Publications Warehouse

Whitney, James E.; Whittier, Joanna B.; Paukert, Craig P.

2017-01-01

Environmental filtering and competitive exclusion are hypotheses frequently invoked in explaining species' environmental niches (i.e., geographic distributions). A key assumption in both hypotheses is that the functional niche (i.e., species traits) governs the environmental niche, but few studies have rigorously evaluated this assumption. Furthermore, phylogeny could be associated with these hypotheses if it is predictive of functional niche similarity via phylogenetic signal or convergent evolution, or of environmental niche similarity through phylogenetic attraction or repulsion. The objectives of this study were to investigate relationships between environmental niches, functional niches, and phylogenies of fishes of the Upper (UCRB) and Lower (LCRB) Colorado River Basins of southwestern North America. We predicted that functionally similar species would have similar environmental niches (i.e., environmental filtering) and that closely related species would be functionally similar (i.e., phylogenetic signal) and possess similar environmental niches (i.e., phylogenetic attraction). Environmental niches were quantified using environmental niche modeling, and functional similarity was determined using functional trait data. Nonnatives in the UCRB provided the only support for environmental filtering, which resulted from several warmwater nonnatives having dam number as a common predictor of their distributions, whereas several cool- and coldwater nonnatives shared mean annual air temperature as an important distributional predictor. Phylogenetic signal was supported for both natives and nonnatives in both basins. Lastly, phylogenetic attraction was only supported for native fishes in the LCRB and for nonnative fishes in the UCRB. Our results indicated that functional similarity was heavily influenced by evolutionary history, but that phylogenetic relationships and functional traits may not always predict the environmental distribution of species. However, the

Testing statistical self-similarity in the topology of river networks

USGS Publications Warehouse

Troutman, Brent M.; Mantilla, Ricardo; Gupta, Vijay K.

2010-01-01

Recent work has demonstrated that the topological properties of real river networks deviate significantly from predictions of Shreve's random model. At the same time the property of mean self-similarity postulated by Tokunaga's model is well supported by data. Recently, a new class of network model called random self-similar networks (RSN) that combines self-similarity and randomness has been introduced to replicate important topological features observed in real river networks. We investigate if the hypothesis of statistical self-similarity in the RSN model is supported by data on a set of 30 basins located across the continental United States that encompass a wide range of hydroclimatic variability. We demonstrate that the generators of the RSN model obey a geometric distribution, and self-similarity holds in a statistical sense in 26 of these 30 basins. The parameters describing the distribution of interior and exterior generators are tested to be statistically different and the difference is shown to produce the well-known Hack's law. The inter-basin variability of RSN parameters is found to be statistically significant. We also test generator dependence on two climatic indices, mean annual precipitation and radiative index of dryness. Some indication of climatic influence on the generators is detected, but this influence is not statistically significant with the sample size available. Finally, two key applications of the RSN model to hydrology and geomorphology are briefly discussed.

Model-free aftershock forecasts constructed from similar sequences in the past

NASA Astrophysics Data System (ADS)

van der Elst, N.; Page, M. T.

2017-12-01

The basic premise behind aftershock forecasting is that sequences in the future will be similar to those in the past. Forecast models typically use empirically tuned parametric distributions to approximate past sequences, and project those distributions into the future to make a forecast. While parametric models do a good job of describing average outcomes, they are not explicitly designed to capture the full range of variability between sequences, and can suffer from over-tuning of the parameters. In particular, parametric forecasts may produce a high rate of "surprises" - sequences that land outside the forecast range. Here we present a non-parametric forecast method that cuts out the parametric "middleman" between training data and forecast. The method is based on finding past sequences that are similar to the target sequence, and evaluating their outcomes. We quantify similarity as the Poisson probability that the observed event count in a past sequence reflects the same underlying intensity as the observed event count in the target sequence. Event counts are defined in terms of differential magnitude relative to the mainshock. The forecast is then constructed from the distribution of past sequences outcomes, weighted by their similarity. We compare the similarity forecast with the Reasenberg and Jones (RJ95) method, for a set of 2807 global aftershock sequences of M≥6 mainshocks. We implement a sequence-specific RJ95 forecast using a global average prior and Bayesian updating, but do not propagate epistemic uncertainty. The RJ95 forecast is somewhat more precise than the similarity forecast: 90% of observed sequences fall within a factor of two of the median RJ95 forecast value, whereas the fraction is 85% for the similarity forecast. However, the surprise rate is much higher for the RJ95 forecast; 10% of observed sequences fall in the upper 2.5% of the (Poissonian) forecast range. The surprise rate is less than 3% for the similarity forecast. The similarity

Privacy-preserving matching of similar patients.

PubMed

Vatsalan, Dinusha; Christen, Peter

2016-02-01

The identification of similar entities represented by records in different databases has drawn considerable attention in many application areas, including in the health domain. One important type of entity matching application that is vital for quality healthcare analytics is the identification of similar patients, known as similar patient matching. A key component of identifying similar records is the calculation of similarity of the values in attributes (fields) between these records. Due to increasing privacy and confidentiality concerns, using the actual attribute values of patient records to identify similar records across different organizations is becoming non-trivial because the attributes in such records often contain highly sensitive information such as personal and medical details of patients. Therefore, the matching needs to be based on masked (encoded) values while being effective and efficient to allow matching of large databases. Bloom filter encoding has widely been used as an efficient masking technique for privacy-preserving matching of string and categorical values. However, no work on Bloom filter-based masking of numerical data, such as integer (e.g. age), floating point (e.g. body mass index), and modulus (numbers wrap around upon reaching a certain value, e.g. date and time), which are commonly required in the health domain, has been presented in the literature. We propose a framework with novel methods for masking numerical data using Bloom filters, thereby facilitating the calculation of similarities between records. We conduct an empirical study on publicly available real-world datasets which shows that our framework provides efficient masking and achieves similar matching accuracy compared to the matching of actual unencoded patient records. Copyright © 2015 Elsevier Inc. All rights reserved.

Age and origin of the Merrimack terrane, southeastern New England: A detrital zircon U-Pb geochronology study

NASA Astrophysics Data System (ADS)

Sorota, Kristin

Metasedimentary rocks of the Merrimack terrane (MT) originated as a thick cover sequence on Ganderia consisting of sandstones, calcareous sandstones, pelitic rocks and turbidites. In order to investigate the age, provenance and stratigraphic order of these rocks and correlations with adjoining terranes, detrital zircon suites from 7 formations across the MT along a NNE-trending transect from east-central Massachusetts to SE New Hampshire were analyzed by U-Pb LA-ICP-MS methods on 90-140 grains per sample. The youngest detrital zircons in the western units, the Worcester, Oakdale and Paxton Formations, are ca. 438 Ma while those in the Kittery, Eliot and Berwick Formations in the northeast are ca. 426 Ma. The Tower Hill Formation previously interpreted to form the easternmost unit of the MT in MA, has a distinctly different zircon distribution with its youngest zircon population in the Cambrian. All samples except for the Tower Hill Formation have detrital zircon age distributions with significant peaks in the mid-to late Ordovician, similar abundances of early Paleozoic and late Neoproterozoic zircons, significant input from ˜1.0 to ˜1.8 Ga sources and limited Archean grains. The similarities in zircon provenance suggest that all units across the terrane, except for the Tower Hill Formation, belong to a single sequence of rocks, with similar sources and with the units in the NE possibly being somewhat younger than those in east-central Massachusetts. The continuous zircon age distributions observed throughout the Mesoproterozoic and late Paleoproterozoic are consistent with an Amazonian source. All samples, except the Tower Hill Formation, show sedimentary input from both Ganderian and Laurentian sources and suggest that Laurentian input increases as the maximum depositional age decreases.

The changing age distribution in Indonesia and some consequences.

PubMed

Nam, C B; Dasvarma, G L; Rahardjo, S P

1991-08-01

"Beginning with a discussion of the sources and quality of Indonesian age data by sex, this paper examines the changes in the functional age groups of the population of Indonesia from 1971 to the year 2005, and the implications of these changes for education, labour force participation, dependency ratios and fertility. Data for the period 1971 to 1985 are based on actual enumerations, while those for the period 1990 to 2005 are based on projections. Although the provisional totals of the 1990 Census had been released before the publication of this paper, their breakdown by age was still not available. The functional age categories discussed in the paper include the pre-school years, the primary and intermediate school ages, the teenage years, the reproductive ages of women, the principal working ages and the post-work years. It concludes with a discussion of various policy and planning implications of these changes." excerpt

New similarity of triangular fuzzy number and its application.

PubMed

Zhang, Xixiang; Ma, Weimin; Chen, Liping

2014-01-01

The similarity of triangular fuzzy numbers is an important metric for application of it. There exist several approaches to measure similarity of triangular fuzzy numbers. However, some of them are opt to be large. To make the similarity well distributed, a new method SIAM (Shape's Indifferent Area and Midpoint) to measure triangular fuzzy number is put forward, which takes the shape's indifferent area and midpoint of two triangular fuzzy numbers into consideration. Comparison with other similarity measurements shows the effectiveness of the proposed method. Then, it is applied to collaborative filtering recommendation to measure users' similarity. A collaborative filtering case is used to illustrate users' similarity based on cloud model and triangular fuzzy number; the result indicates that users' similarity based on triangular fuzzy number can obtain better discrimination. Finally, a simulated collaborative filtering recommendation system is developed which uses cloud model and triangular fuzzy number to express users' comprehensive evaluation on items, and result shows that the accuracy of collaborative filtering recommendation based on triangular fuzzy number is higher.

Average is Boring: How Similarity Kills a Meme's Success

PubMed Central

Coscia, Michele

2014-01-01

Every day we are exposed to different ideas, or memes, competing with each other for our attention. Previous research explained popularity and persistence heterogeneity of memes by assuming them in competition for limited attention resources, distributed in a heterogeneous social network. Little has been said about what characteristics make a specific meme more likely to be successful. We propose a similarity-based explanation: memes with higher similarity to other memes have a significant disadvantage in their potential popularity. We employ a meme similarity measure based on semantic text analysis and computer vision to prove that a meme is more likely to be successful and to thrive if its characteristics make it unique. Our results show that indeed successful memes are located in the periphery of the meme similarity space and that our similarity measure is a promising predictor of a meme success. PMID:25257730

AIDS in adults 50 years of age and over: characteristics, trends and spatial distribution of the risk.

PubMed

Nogueira, Jordana de Almeida; Silva, Antônia Oliveira; Sá, Laísa Ribeiro de; Almeida, Sandra Aparecida de; Monroe, Aline Aparecida; Villa, Tereza Cristina Scatena

2014-01-01

to analyze the sociodemographic characteristics, epidemic trend and spatial distribution of the risk of AIDS in adults 50 years of age and over. population-based, ecological study, that used secondary data from the Notifiable Disease Information System (Sinan/AIDS) of Paraíba state from the period January 2000 to December 2010. during the study period, 307 cases of AIDS were reported among people 50 years of age or over. There was a predominance of males (205/66, 8%), mixed race, and low education levels. The municipalities with populations above 100 thousand inhabitants reported 58.5% of the cases. There was a progressive increase in cases among women; an increasing trend in the incidence (positive linear correlation); and an advance in the geographical spread of the disease, with expansion to the coastal region and to the interior of the state, reaching municipalities with populations below 30 thousand inhabitants. In some locations the risk of disease was 100 times greater than the relative risk for the state. aging, with the feminization and interiorization of the epidemic in adults 50 years of age and over, confirms the need for the induction of affirmative policies targeted toward this age group.

The distribution of the indicator height for age of Mexican children and adolescents with Down syndrome according to different reference standards.

PubMed

Peña Rivera, Adriana Graciela; Vásquez Garibay, Edgar Manuel; Troyo Sanromán, Rogelio; Romero Velarde, Enrique; Caro Sabido, Erika; Ramírez Díaz, Joanie

2015-06-01

To compare the indicator height for age in Mexican children with Down Syndrome (DS) with two different reference patterns of growth (American and Spanish) that might be suitable for the Mexican population. A cross-sectional study was performed including 235 Mexican children and adolescents of both sexes with DS aged 45 days to 16 years enrolled in two specialized schools in the metropolitan area of Guadalajara. The dependent variables were weight/age; height/age; weight/ height and BMI. The data expressed was percentiles and the chi-square test was used to compare the distribution of the height/age index with American and Spanish reference patterns. In addition, a chi-square test was performed for the goodness of fit of the height/age index, with breakpoints lower and greater than the 50th percentile. The percentage of participants who were below the 50th percentile in the height/age index was significantly higher with the Spanish vs. the American reference pattern. The chi-square test for goodness of fit showed that the frequency of cases located below the 50th percentile in the height/age index was significantly higher with the American pattern in the age groups of 0 to 36 months (p = 0.022) and 37 to 72 months (p <0.001), but it was not significant (p = 0.225) in the older than 72 months age group. The American reference pattern is a better fit for the growth of Mexican children with DS compared with the Spanish reference pattern, and the distribution profile obtained with the standard growth and WHO reference was not suitable for the assessment of children with Down syndrome. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

The relative age effect in soccer: a match-related perspective.

PubMed

Vaeyens, Roel; Philippaerts, Renaat M; Malina, Robert M

2005-07-01

Asymmetries in the distributions of birth dates in senior professional and youth soccer players have been interpreted as evidence for systematic discrimination against individuals born shortly before the cut-off date in assigning youth to specific age groups. This concept is known as the "relative age effect". The results of a longitudinal study of birth date distritubions of 2757 semi-professional and amateur senior soccer players in Belgium are presented. Records for competitive games were available in official statistics provided by the Royal Belgian Football Association. The chi-square statistic was used to examine differences between observed and expected birth date distributions. Regression analyses indicated a shift of bias when two different start dates were compared. Players born in the early part of the new age band (January to March) were over-represented compared with players born late in the new selection period (October to December). However, players with birthdays at the start of the old selection year (August) were still represented. In a retrospective analysis of 2138 players, variables indicative of match involvement, number of selections for matches, and time played were examined in relation to the relative age effect. The group of semi-professional and amateur senior soccer players born in the first quarter of the selected age band received more playing opportunities. Comparisons of birth date distributions (traditional approach to relative age effect) with match-related variables gave similar, though not entirely consistent, results. However, there were no differences for the mean number of selections and for playing minutes between players born at the start or the end of the selection year. Our findings suggest that match-based variables may provide a more reliable indication of the relative age effect in soccer.

Statistically advanced, self-similar, radial probability density functions of atmospheric and under-expanded hydrogen jets

NASA Astrophysics Data System (ADS)

Ruggles, Adam J.

2015-11-01

This paper presents improved statistical insight regarding the self-similar scalar mixing process of atmospheric hydrogen jets and the downstream region of under-expanded hydrogen jets. Quantitative planar laser Rayleigh scattering imaging is used to probe both jets. The self-similarity of statistical moments up to the sixth order (beyond the literature established second order) is documented in both cases. This is achieved using a novel self-similar normalization method that facilitated a degree of statistical convergence that is typically limited to continuous, point-based measurements. This demonstrates that image-based measurements of a limited number of samples can be used for self-similar scalar mixing studies. Both jets exhibit the same radial trends of these moments demonstrating that advanced atmospheric self-similarity can be applied in the analysis of under-expanded jets. Self-similar histograms away from the centerline are shown to be the combination of two distributions. The first is attributed to turbulent mixing. The second, a symmetric Poisson-type distribution centered on zero mass fraction, progressively becomes the dominant and eventually sole distribution at the edge of the jet. This distribution is attributed to shot noise-affected pure air measurements, rather than a diffusive superlayer at the jet boundary. This conclusion is reached after a rigorous measurement uncertainty analysis and inspection of pure air data collected with each hydrogen data set. A threshold based upon the measurement noise analysis is used to separate the turbulent and pure air data, and thusly estimate intermittency. Beta-distributions (four parameters) are used to accurately represent the turbulent distribution moments. This combination of measured intermittency and four-parameter beta-distributions constitutes a new, simple approach to model scalar mixing. Comparisons between global moments from the data and moments calculated using the proposed model show excellent

Racial differences in self-rated health at similar levels of physical functioning: an examination of health pessimism in the health, aging, and body composition study.

PubMed

Spencer, S Melinda; Schulz, Richard; Rooks, Ronica N; Albert, Steven M; Thorpe, Roland J; Brenes, Gretchen A; Harris, Tamara B; Koster, Annemarie; Satterfield, Suzanne; Ayonayon, Hilsa N; Newman, Anne B

2009-01-01

The health pessimism hypothesis suggests that Black elders are more pessimistic about health than Whites and therefore tend to report lower self-rated health (SRH) at comparable health status. The current analysis examined the factors associated with SRH and tested the health pessimism hypothesis among older adults at similar levels of physical functioning. The study example included 2,729 Health, Aging, and Body Composition study participants aged 70-79 years. We used hierarchical logistic regression to examine the association between race and SRH while adjusting for demographic, physical health, and psychosocial factors. The analyses were repeated for participants at similar levels of objective functioning to test the health pessimism hypothesis. The association between race and SRH remained independent of physical and psychosocial health variables, with Whites being 3.7 times more likely than Black elders to report favorable SRH. This association was significant at each level of physical functioning and greater at the higher (odds ratio [OR] = 5.5) versus lower (OR = 2.2) levels of functioning. The results suggest greater health pessimism among Black elders and expand previous work by including objective functioning in multidimensional models to deconstruct race variations in the SRH of older adults.

The distribution of SIgA and IgG antibody-secreting cells in the palatine tonsils of Bactrian camels (Camelus bactrianus) of different ages.

PubMed

Jia, Shuai; Zhang, Wangdong; Tan, Xuefen; He, Wanhong; Wang, Wenhui

2017-05-01

Secretory immunoglobulin A (SIgA) antibody-secreting cells (ASCs) are the major effector cells of mucosal immunity, and immunoglobulin G (IgG) ASCs are also associated with mucosal immunity. This study aimed to explore the distribution of these 2 ASC populations in the palatine tonsils of Bactrian camels of different ages. Eighteen Bactrian camels were divided into the following three age groups: pubertal (3-5 years), middle-aged (6-16 years) and old (17-20 years). SIgA and IgG ASCs within different sites of the palatine tonsils were observed through histological and immunohistochemical techniques, and their densities were analyzed using statistical methods. The results from all age groups showed that both the SIgA and IgG ASCs were primarily distributed in the subepithelial compartments of the reticulated crypt epithelium and secondarily distributed in the subepithelial compartments of the stratified surface squamous epithelium, with a few ASCs located in the extrafollicular region. Their densities in these three areas were significantly decreased in turn (P<0.05). However, the densities of SIgA ASCs were significantly higher than IgG ASCs in the same regions (P<0.05), and the densities of both ASC populations decreased with age. The results confirmed that Bactrian camel palatine tonsils are the primary mucosal immune organ producing SIgA ASCs, and the subepithelial compartment of the reticulated crypt epithelium is the primary region for the colonization and functional activity of SIgA and IgG ASCs.

Using groundwater age distributions to understand changes in methyl tert-butyl ether (MtBE) concentrations in ambient groundwater, northeastern United States

USGS Publications Warehouse

Lindsey, Bruce; Ayotte, Joseph; Jurgens, Bryant; DeSimone, Leslie A.

2017-01-01

Temporal changes in methyl tert-butyl ether (MtBE) concentrations in groundwater were evaluated in the northeastern United States, an area of the nation with widespread low-level detections of MtBE based on a national survey of wells selected to represent ambient conditions. MtBE use in the U.S. peaked in 1999 and was largely discontinued by 2007. Six well networks, each representing specific areas and well types (monitoring or supply wells), were each sampled at 10 year intervals between 1996 and 2012. Concentrations were decreasing or unchanged in most wells as of 2012, with the exception of a small number of wells where concentrations continue to increase. Statistically significant increasing concentrations were found in one network sampled for the second time shortly after the peak of MtBE use, and decreasing concentrations were found in two networks sampled for the second time about 10 years after the peak of MtBE use. Simulated concentrations from convolutions of estimates for concentrations of MtBE in recharge water with age distributions from environmental tracer data correctly predicted the direction of MtBE concentration changes in about 65 percent of individual wells. The best matches between simulated and observed concentrations were found when simulating recharge concentrations that followed the pattern of national MtBE use. Some observations were matched better when recharge was modeled as a plume moving past the well from a spill at one point in time. Modeling and sample results showed that wells with young median ages and narrow age distributions responded more quickly to changes in the contaminant source than wells with older median ages and broad age distributions. Well depth and aquifer type affect these responses. Regardless of the timing of decontamination, all of these aquifers show high susceptibility for contamination by a highly soluble, persistent constituent.

Random Partition Distribution Indexed by Pairwise Information

PubMed Central

Dahl, David B.; Day, Ryan; Tsai, Jerry W.

2017-01-01

We propose a random partition distribution indexed by pairwise similarity information such that partitions compatible with the similarities are given more probability. The use of pairwise similarities, in the form of distances, is common in some clustering algorithms (e.g., hierarchical clustering), but we show how to use this type of information to define a prior partition distribution for flexible Bayesian modeling. A defining feature of the distribution is that it allocates probability among partitions within a given number of subsets, but it does not shift probability among sets of partitions with different numbers of subsets. Our distribution places more probability on partitions that group similar items yet keeps the total probability of partitions with a given number of subsets constant. The distribution of the number of subsets (and its moments) is available in closed-form and is not a function of the similarities. Our formulation has an explicit probability mass function (with a tractable normalizing constant) so the full suite of MCMC methods may be used for posterior inference. We compare our distribution with several existing partition distributions, showing that our formulation has attractive properties. We provide three demonstrations to highlight the features and relative performance of our distribution. PMID:29276318

The relationship between groundwater ages, streamflow ages, and storage selection functions under stationary conditions

NASA Astrophysics Data System (ADS)

Berghuijs, W.; Kirchner, J. W.

2017-12-01

Waters in aquifers are often much older than the streamwaters that drain them. Simple physically based reasoning suggests that these age contrasts should be expected wherever catchments are heterogeneous. However, a general quantitative catchment-scale explanation of these age contrasts remains elusive. We show that under stationary conditions conservation of mass and age dictate that the age distribution of water stored in a catchment can be directly estimated from the age distribution of its outflows, and vice versa. This in turn implies that the catchment's preference for the release or retention of waters of different ages can be estimated directly from the age distribution of outflow under stationary conditions. Using simple models of transit times, we show that the mean age of stored water can range from half as old as the mean age of streamflow (for plug flow conditions) to almost infinitely older (for strongly preferential flow). Streamflow age distributions reported in the literature often have long upper tails, consistent with preferential flow and implying that storage ages are substantially older than streamflow ages. Mean streamflow ages reported in the literature imply that most streamflow originates from a thin veneer of total groundwater storage. This preferential release of young streamflow implies that most groundwater is exchanged only slowly with the surface, and consequently must be very old. Where information is available for both storage ages and streamflow ages, our analysis establishes consistency relationships through which each could be used to better constrain the other. By quantifying the relationship between groundwater and streamflow ages, our analysis provides tools to jointly assess both of these important catchment properties.

Gender Distribution of Pediatric Stone Formers

NASA Astrophysics Data System (ADS)

Novak, Thomas E.; Trock, Bruce J.; Lakshmanan, Yegappan; Gearhart, John P.; Matlaga, Brian R.

2008-09-01

Recent epidemiologic evidence suggests that the gender prevalence among adult stone-formers is changing, with an increasing incidence of stone disease among women. No similar data have ever been reported for the pediatric stone-forming population. We performed a study to define the gender distribution among pediatric stone-formers using a large-scale national pediatric database. Our findings suggest that gender distribution among stone formers varies by age with male predominance in the first decade of life shifting to female predominance in the second decade. In contrast to adults, females in the pediatric population are more commonly affected by stones than are males. The incidence of pediatric stone disease appears to be increasing at a great rate in both sexes. Further studies should build on this hypothesis-generating work and define the effects of metabolic and environmental risk factors that may influence stone risk in the pediatric patient population

Competitive Wrestling-related Injuries in School Aged Athletes in U.S. Emergency Departments

PubMed Central

Myers, Richard J.; Linakis, Seth W.; Mello, Michael J.; Linakis, James G.

2010-01-01

Objective To describe the characteristics of wrestling injuries occurring in male athletes aged 7–17 treated in United States (U.S.) emergency departments (ED) from 2000–2006, and to compare injury patterns between younger & older youth wrestlers. Methods A stratified probability sample of U.S. hospitals providing emergency services in the National Electronic Injury Surveillance System was used for 2000–2006. ED visits for injuries sustained in organized wrestling were analyzed for male patients ages 7–17 years old (subdivided into 7–11 years old [youth group] and 12–17 years old [scholastic group]). Results During the study period, there were an estimated 167,606 ED visits for wrestling injuries in 7–17 years old U.S. males, with 152,710 (91.1%) occurring in the older (12–17 years old) group. The annual injury incidence was 6.49 injuries/1,000 wrestlers in the youth group and 29.57 injuries/1,000 wrestlers in the scholastic group. The distribution of diagnoses was similar in both age groups, with sprain/strain as the most common diagnosis, followed by fracture and contusion/abrasion. Distributions of injury by location were significantly different between groups (p=0.02), although both groups exhibited approximately 75% of all injuries from the waist up. Overexertion and struck by/against were the most common precipitating and direct mechanisms in both groups, respectively. Over 97% of all injured wrestlers were treated and released. Conclusion The types of injury in youth (7–11 years old) wrestlers are similar to those of scholastic (12–17 years old) wrestlers, although the distribution of body parts injured differs between the age groups. The majority of injuries occurs above the waist and may be a target for prevention strategies. PMID:21293763

Diversity in aconitine alkaloid profile of Aconitum plants in Hokkaido contrasts with their genetic similarity.

PubMed

Kakiuchi, Nobuko; Atsumi, Toshiyuki; Higuchi, Mari; Kamikawa, Shohei; Miyako, Haruka; Wakita, Yuriko; Ohtsuka, Isao; Hayashi, Shigeki; Hishida, Atsuyuki; Kawahara, Nobuo; Nishizawa, Makoto; Yamagishi, Takashi; Kadota, Yuichi

2015-01-01

Aconite tuber is a representative crude drug for warming the body internally in Japanese Kampo medicine and Chinese traditional medicine. The crude drug is used in major prescriptions for the aged. Varieties of Aconitum plants are distributed throughout the Japanese Islands, especially Hokkaido. With the aim of identifying the medicinal potential of Aconitum plants from Hokkaido, 107 specimens were collected from 36 sites in the summer of 2011 and 2012. Their nuclear DNA region, internal transcribed spacer (ITS), and aconitine alkaloid contents were analyzed. Phylogenic analysis of ITS by maximum parsimony analysis showed that the majority of the specimens were grouped into one cluster (cluster I), separated from the other cluster (cluster II) consisting of alpine specimens. The aconitine alkaloid content of the tuberous roots of 76 specimens showed 2 aspects-specimens from the same collection site showed similar aconitine alkaloid profiles, and cluster I specimens from different habitats showed various alkaloid profiles. Environmental pressure of each habitat is presumed to have caused the morphology and aconitine alkaloid profile of these genetically similar specimens to diversify.

Some analytical models to estimate maternal age at birth using age-specific fertility rates.

PubMed

Pandey, A; Suchindran, C M

1995-01-01

"A class of analytical models to study the distribution of maternal age at different births from the data on age-specific fertility rates has been presented. Deriving the distributions and means of maternal age at birth of any specific order, final parity and at next-to-last birth, we have extended the approach to estimate parity progression ratios and the ultimate parity distribution of women in the population.... We illustrate computations of various components of the model expressions with the current fertility experiences of the United States for 1970." excerpt

Histopathological confirmation of similar intramucosal distribution of fluorescein in both intravenous administration and local mucosal application for probe-based confocal laser endomicroscopy of the normal stomach.

PubMed

Nonaka, Kouichi; Ohata, Ken; Ban, Shinichi; Ichihara, Shin; Takasugi, Rumi; Minato, Yohei; Tashima, Tomoaki; Matsuyama, Yasushi; Takita, Maiko; Matsuhashi, Nobuyuki; Neumann, Helmut

2015-12-16

Probe-based confocal laser endomicroscopy (pCLE) is capable of acquiring in vivo magnified cross-section images of the gastric mucosa. Intravenous injection of fluorescein sodium is used for confocal imaging. However, it is still under debate if local administration of the dye to the mucosa is also effective for confocal imaging as it is not yet clear if topical application also reveals the intramucosal distribution of fluorescein. The objective of this study was to evaluate the intramucosal distribution of fluorescein sodium after topical application and to compare the distribution to the conventional intravenous injection used for confocal imaging. pCLE of the stomach uninfected with Helicobacter pylori was performed in a healthy male employing intravenous administration and local mucosal application of fluorescein. The mucosa of the lower gastric body was biopsied 1 min and 5 min after intravenous administration or local mucosal application of fluorescein, and the distribution of fluorescein in the biopsy samples was examined histologically. Green fluorescence was already observed in the cytoplasm of fundic glandular cells in the biopsied deep mucosa 1 min after local mucosal application of fluorescein. It was also observed in the foveolar lumen and inter-foveolar lamina propria, although it was noted at only a few sites. In the tissue biopsied 5 min after the local mucosal application of fluorescein, green fluorescence was more frequently noted in the cytoplasm of fundic glandular cells than in that 1 min after the local mucosal application of fluorescein, although obvious green fluorescence was not identified in the foveolar lumen or inter-foveolar lamina propria. The distribution of intravenously administered fluorescein in the cytoplasm of fundic glandular cells was also clearly observed similarly to that after local mucosal application of fluorescein. Green fluorescence in more cells was observed in many cells 5 min after intravenous administration compared

Non-Fickian dispersion of groundwater age

PubMed Central

Engdahl, Nicholas B.; Ginn, Timothy R.; Fogg, Graham E.

2014-01-01

We expand the governing equation of groundwater age to account for non-Fickian dispersive fluxes using continuous random walks. Groundwater age is included as an additional (fifth) dimension on which the volumetric mass density of water is distributed and we follow the classical random walk derivation now in five dimensions. The general solution of the random walk recovers the previous conventional model of age when the low order moments of the transition density functions remain finite at their limits and describes non-Fickian age distributions when the transition densities diverge. Previously published transition densities are then used to show how the added dimension in age affects the governing differential equations. Depending on which transition densities diverge, the resulting models may be nonlocal in time, space, or age and can describe asymptotic or pre-asymptotic dispersion. A joint distribution function of time and age transitions is developed as a conditional probability and a natural result of this is that time and age must always have identical transition rate functions. This implies that a transition density defined for age can substitute for a density in time and this has implications for transport model parameter estimation. We present examples of simulated age distributions from a geologically based, heterogeneous domain that exhibit non-Fickian behavior and show that the non-Fickian model provides better descriptions of the distributions than the Fickian model. PMID:24976651

A self-similar hierarchy of the Korean stock market

NASA Astrophysics Data System (ADS)

Lim, Gyuchang; Min, Seungsik; Yoo, Kun-Woo

2013-01-01

A scaling analysis is performed on market values of stocks listed on Korean stock exchanges such as the KOSPI and the KOSDAQ. Different from previous studies on price fluctuations, market capitalizations are dealt with in this work. First, we show that the sum of the two stock exchanges shows a clear rank-size distribution, i.e., the Zipf's law, just as each separate one does. Second, by abstracting Zipf's law as a γ-sequence, we define a self-similar hierarchy consisting of many levels, with the numbers of firms at each level forming a geometric sequence. We also use two exponential functions to describe the hierarchy and derive a scaling law from them. Lastly, we propose a self-similar hierarchical process and perform an empirical analysis on our data set. Based on our findings, we argue that all money invested in the stock market is distributed in a hierarchical way and that a slight difference exists between the two exchanges.

Age-Specific Injury Risk Curves for Distributed, Anterior Thoracic Loading of Various Sizes of Adults Based on Sternal Deflections.

PubMed

Mertz, Harold J; Prasad, Priya; Dalmotas, Dainius J; Irwin, Annette L

2016-11-01

Injury Risk Curves are developed from cadaver data for sternal deflections produced by anterior, distributed chest loads for a 25, 45, 55, 65 and 75 year-old Small Female, Mid-Size Male and Large Male based on the variations of bone strengths with age. These curves show that the risk of AIS ≥ 3 thoracic injury increases with the age of the person. This observation is consistent with NASS data of frontal accidents which shows that older unbelted drivers have a higher risk of AIS ≥ 3 chest injury than younger drivers.

Direct simulation of groundwater age

USGS Publications Warehouse

Goode, Daniel J.

1996-01-01

A new method is proposed to simulate groundwater age directly, by use of an advection-dispersion transport equation with a distributed zero-order source of unit (1) strength, corresponding to the rate of aging. The dependent variable in the governing equation is the mean age, a mass-weighted average age. The governing equation is derived from residence-time-distribution concepts for the case of steady flow. For the more general case of transient flow, a transient governing equation for age is derived from mass-conservation principles applied to conceptual “age mass.” The age mass is the product of the water mass and its age, and age mass is assumed to be conserved during mixing. Boundary conditions include zero age mass flux across all noflow and inflow boundaries and no age mass dispersive flux across outflow boundaries. For transient-flow conditions, the initial distribution of age must be known. The solution of the governing transport equation yields the spatial distribution of the mean groundwater age and includes diffusion, dispersion, mixing, and exchange processes that typically are considered only through tracer-specific solute transport simulation. Traditional methods have relied on advective transport to predict point values of groundwater travel time and age. The proposed method retains the simplicity and tracer-independence of advection-only models, but incorporates the effects of dispersion and mixing on volume-averaged age. Example simulations of age in two idealized regional aquifer systems, one homogeneous and the other layered, demonstrate the agreement between the proposed method and traditional particle-tracking approaches and illustrate use of the proposed method to determine the effects of diffusion, dispersion, and mixing on groundwater age.

Confabulation in healthy aging is related to interference of overlearned, semantically similar information on episodic memory recall.

PubMed

Dalla Barba, Gianfranco; Attali, Eve; La Corte, Valentina

2010-07-01

Normal aging is characterized by reduced performance on tasks of long-term memory. Older adults (OA) not only show reduced performance on tasks of recall and recognition memory, but also, compared to young adults (YA), are more vulnerable to memory distortions. In this study we describe the performance of a group of OA and a group of YA on the recall of three different types of story: a previously unknown story, a well-known fairy tale (Sleeping Beauty), and a modified well-known fairy tale (Little Red Riding Hood is not eaten by the wolf). The aim of our study was to test the hypothesis that in OA strongly represented, overlearned information interferes with episodic recall-that is, the retrieval of specific, unique past episodes. OA produced significantly more confabulations than YA and in particular in the recall of the modified fairy tale. Our findings indicate that the interference of strongly represented, overlearned information in episodic memory recall is implicated in the production of confabulations in OA. This effect is particularly prominent when the to-be remembered episodic information shows strong semantic similarities with preexisting, overlearned information.

Endogenic craters on basaltic lava flows - Size frequency distributions

NASA Technical Reports Server (NTRS)

Greeley, R.; Gault, D. E.

1979-01-01

Circular crater forms, termed collapse depressions, which occur on many basalt flows on the earth have also been detected on the moon and Mars and possibly on Mercury and Io. The admixture of collapse craters with impact craters would affect age determinations of planetary surface units based on impact crater statistics by making them appear anomalously old. In the work described in the present paper, the techniques conventionally used in planetary crater counting were applied to the determination of the size range and size frequency distribution of collapse craters on lava flows in Idaho, California, and New Mexico. Collapse depressions range in size from 3 to 80 m in diameter; their cumulative size distributions are similar to those of small impact craters on the moon.

The Distribution of SIgA and IgG Antibody-Secreting Cells in the Small Intestine of Bactrian Camels (Camelus bactrianus) of Different Ages

PubMed Central

Zhang, Wang-Dong; Wang, Wen-Hui; Jia, Shuai

2016-01-01

Secretory immunoglobulin A (SIgA) and immunoglobulin G (IgG) antibody-secreting cells (ASCs) are two important cell types in the mucosal immune system. This study aimed to explore the distribution of these ASC populations in the small intestine of Bactrian camels of different ages. Twenty-four Alashan Bactrian camels were divided into the following four age groups: young (1–2 years), pubertal (3–5 years), middle-aged (6–16 years) and old (17–20 years). SIgA and IgG ASCs in the intestinal mucosa lamina propria (LP) were observed and analyzed using immunohistochemcal techniques. The results from all age groups show that both SIgA and IgG ASCs were diffusely distributed in the intestinal LP, and some cells aggregated around the crypts. Moreover, the densities of the two ASC populations gradually increased from the duodenum to the jejunum and then decreased in the ileum. Meanwhile, there were more SIgA ASCs than IgG ASCs in the duodenum, jejunum, and ileum, and these differences were significant in the young and pubertal groups (P<0.05). In addition, the SIgA and IgG ASC densities increased from the young to the pubertal period, peaked at puberty, and then gradually decreased with age. The results demonstrate that the SIgA and IgG ASC distributions help to form two immunoglobulin barriers in the intestinal mucosa to provide full protection, helping to maintain homeostasis. These findings also underscore the importance of researching the development and degeneration of intestinal mucosal immunity in Bactrian camels. PMID:27249417

The Distribution of SIgA and IgG Antibody-Secreting Cells in the Small Intestine of Bactrian Camels (Camelus bactrianus) of Different Ages.

PubMed

Zhang, Wang-Dong; Wang, Wen-Hui; Jia, Shuai

2016-01-01

Secretory immunoglobulin A (SIgA) and immunoglobulin G (IgG) antibody-secreting cells (ASCs) are two important cell types in the mucosal immune system. This study aimed to explore the distribution of these ASC populations in the small intestine of Bactrian camels of different ages. Twenty-four Alashan Bactrian camels were divided into the following four age groups: young (1-2 years), pubertal (3-5 years), middle-aged (6-16 years) and old (17-20 years). SIgA and IgG ASCs in the intestinal mucosa lamina propria (LP) were observed and analyzed using immunohistochemcal techniques. The results from all age groups show that both SIgA and IgG ASCs were diffusely distributed in the intestinal LP, and some cells aggregated around the crypts. Moreover, the densities of the two ASC populations gradually increased from the duodenum to the jejunum and then decreased in the ileum. Meanwhile, there were more SIgA ASCs than IgG ASCs in the duodenum, jejunum, and ileum, and these differences were significant in the young and pubertal groups (P<0.05). In addition, the SIgA and IgG ASC densities increased from the young to the pubertal period, peaked at puberty, and then gradually decreased with age. The results demonstrate that the SIgA and IgG ASC distributions help to form two immunoglobulin barriers in the intestinal mucosa to provide full protection, helping to maintain homeostasis. These findings also underscore the importance of researching the development and degeneration of intestinal mucosal immunity in Bactrian camels.

Managing uneven-aged stands

Treesearch

Jay R. Law; Craig G. Lorimer

1989-01-01

Maintaining uneven-aged stands involves cutting trees from a range of diameter classes in such a way that the residual stand has a balanced, steeply descending diameter distribution curve (fig. 1). The objective is to distribute trees by diameter classes so that over time the stand contains trees of different ages and sizes.

Age, geochemical composition, and distribution of Oligocene ignimbrites in the northern Sierra Nevada, California: Implications for landscape morphology, elevation, and drainage divide geography of the Nevadaplano

USGS Publications Warehouse

Cassel, Elizabeth J.; Calvert, Andrew T.; Graham, Stephan A.

2009-01-01

To gain a better understanding of the topographic and landscape evolution of the Cenozoic Sierra Nevada and Basin and Range, we combine geochemical and isotopic age correlations with palaeoaltimetry data from widely distributed ignimbrites in the northern Sierra Nevada, California. A sequence of Oligocene rhyolitic ignimbrites is preserved across the modern crest of the range and into the western foothills. Using trace and rare earth element geochemical analyses of volcanic glass, these deposits have been correlated to ignimbrites described and isotopically dated in the Walker Lane fault zone and in central Nevada (Henry et al., 2004, Geologic map of the Dogskin mountain quadrangle; Washoe County, Nevada; Faulds et al., 2005, Geology, v. 33, p. 505–508). Ignimbrite deposits were sampled within the northern Sierra Nevada and western Nevada, and four distinct geochemical compositions were identified. The majority of samples from within the northern Sierra Nevada have compositions similar to the tuffs of Axehandle Canyon or Rattlesnake Canyon, both likely sourced from the same caldera complex in either the Clan Alpine Mountains or the Stillwater Range, or to the tuff of Campbell Creek, sourced from the Desatoya Mountains caldera. New 40Ar/39Ar age determinations from these samples of 31.2, 30.9, and 28.7 Ma, respectively, support these correlations. Based on an Oligocene palinspastic reconstruction of the region, our results show that ignimbrites travelled over 200 km from their source calderas across what is now the crest of the Sierra Nevada, and that during that time, no drainage divide existed between the ignimbrite source calderas in central Nevada and sample locations 200 km to the west. Palaeoaltimetry data from Sierra Nevada ignimbrites, based on the hydrogen isotopic composition of hydration water in glass, reflect the effect of a steep western slope on precipitation and indicate that the area had elevations similar to the present-day range. These

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 C.

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.

Transformation and Self-Similarity Properties of Gamma and Weibull Fragment Size Distributions

DTIC Science & Technology

2015-12-01

spray formed when a fast gas stream blows over a liquid volume.” As a theoretical justification, they showed that Gamma size distributions are...of Fracture, 140, 243, 2006 P.-K. Wu, G. A. Ruff, and G. M. Faeth, Primary Breakup in Liquid - Gas Mixing Layers, Atomization and Sprays, 1, 421-440...103 meter (m) barn (b) 1 × 10–28 square meter (m2) gallon (gal, U.S. liquid ) 3.785 412 × 10–3 cubic meter (m3) cubic foot (ft3) 2.831 685 × 10–2

HTRA1 variant confers similar risks to geographic atrophy and neovascular age-related macular degeneration.

PubMed

Cameron, D Joshua; Yang, Zhenglin; Gibbs, Daniel; Chen, Haoyu; Kaminoh, Yuuki; Jorgensen, Adam; Zeng, Jiexi; Luo, Ling; Brinton, Eric; Brinton, Gregory; Brand, John M; Bernstein, Paul S; Zabriskie, Norman A; Tang, Shibo; Constantine, Ryan; Tong, Zongzhong; Zhang, Kang

2007-05-02

Age-related macular degeneration (AMD) is the most common cause of irreversible visual impairment in the developed world. The two forms of advanced AMD, geographic atrophy (GA) and choroidal neovascularization (wet AMD), represent two types of degenerative processes in the macula that lead to loss of central vision. Soft confluent drusen, characterized by deposits in macula without visual loss are considered a precursor of advanced AMD. A single nucleotide polymorphism, rs11200638, in the promoter of HTRA1 has been shown to increases the risk for wet AMD. However, its impact on soft confluent drusen and GA or the relationship between them is unclear. To better understand the role the HTRA1 polymorphism plays in AMD subtypes, we genotyped an expanded Utah population with 658 patients having advanced AMD or soft confluent drusen and 294 normal controls and found that the rs11200638 was significantly associated with GA. This association remains significant conditional on LOC387715 rs10490924. In addition, rs11200638 was significantly associated with soft confluent drusen, which are strongly immunolabeled with HTRA1 antibody in an AMD eye with GA similar to wet AMD. Two-locus analyses were performed for CFH Y402H variant at 1q31 and the HTRA1 polymorphism. Together CFH and HTRA1 risk variants increase the odds of having AMD by more than 40 times. These findings expand the role of HTRA1 in AMD. Understanding the underlying molecular mechanism will provide an important insight in pathogenesis of AMD.

A New Similarity theory for Strongly Unstable Atmospheric Surface Layer

NASA Astrophysics Data System (ADS)

Ji, Yong; She, Zhen-Su

2017-11-01

We apply the structural ensemble dynamics (SED) theory to analyze mean velocity and streamwise turbulence intensity distribution in unstable atmospheric surface layer (ASL). The turbulent kinetic energy balance equation in ASL asserts that above a critical height zL, the buoyancy production cannot be neglected. The SED theory predicts that a stress length function displays a generalized scaling law from z to z 4 / 3. The zL derived from observational data show a two-regime form with Obukhov length L , including a linear dependence for moderate heat flux and a constant regime for large heat flux, extending the Monin-Obukhov similarity theory which is only valid for large | L | . This two-regime description is further extended to model turbulent intensity, with a new similarity coordinate Lz such that the observational data collapse for all L. Finally, we propose a phase diagram for characterizing different ASL flow regimes, and the corresponding flow structures are discussed. In summary, a new similarity theory for unstable atmosphere is constructed, and validated by observational data of the mean velocity and streamwise turbulence intensity distribution for all heat flux regimes.

T cell receptor repertoires of mice and humans are clustered in similarity networks around conserved public CDR3 sequences

PubMed Central

Madi, Asaf; Poran, Asaf; Shifrut, Eric; Reich-Zeliger, Shlomit; Greenstein, Erez; Zaretsky, Irena; Arnon, Tomer; Laethem, Francois Van; Singer, Alfred; Lu, Jinghua; Sun, Peter D; Cohen, Irun R; Friedman, Nir

2017-01-01

Diversity of T cell receptor (TCR) repertoires, generated by somatic DNA rearrangements, is central to immune system function. However, the level of sequence similarity of TCR repertoires within and between species has not been characterized. Using network analysis of high-throughput TCR sequencing data, we found that abundant CDR3-TCRβ sequences were clustered within networks generated by sequence similarity. We discovered a substantial number of public CDR3-TCRβ segments that were identical in mice and humans. These conserved public sequences were central within TCR sequence-similarity networks. Annotated TCR sequences, previously associated with self-specificities such as autoimmunity and cancer, were linked to network clusters. Mechanistically, CDR3 networks were promoted by MHC-mediated selection, and were reduced following immunization, immune checkpoint blockade or aging. Our findings provide a new view of T cell repertoire organization and physiology, and suggest that the immune system distributes its TCR sequences unevenly, attending to specific foci of reactivity. DOI: http://dx.doi.org/10.7554/eLife.22057.001 PMID:28731407

Age at onset in bipolar I affective disorder in the USA and Europe.

PubMed

Bellivier, Frank; Etain, Bruno; Malafosse, Alain; Henry, Chantal; Kahn, Jean-Pierre; Elgrabli-Wajsbrot, Orly; Jamain, Stéphane; Azorin, Jean-Michel; Frank, Ellen; Scott, Jan; Grochocinski, Victoria; Kupfer, David J; Golmard, Jean-Louis; Leboyer, Marion

2014-07-01

To test for differences in reported age at onset (AAO) of bipolar I affective disorder in clinical samples drawn from Europe and the USA. Admixture analysis was used to identify the model best fitting the observed AAO distributions of two large samples of bipolar I patients from Europe and USA (n = 3616 and n = 2275, respectively). Theoretical AAO functions were compared between the two samples. The model best fitting the observed distribution of AAO in both samples was a mixture of three Gaussian distributions. The theoretical AAO functions of bipolar I disorder differed significantly between the European and USA populations, with further analyses indicating that (i) the proportion of patients belonging to the early-onset subgroup was higher in the USA sample (63 vs. 25%) and (ii) mean age at onset (±SD) in the early-onset subgroup was lower for the USA sample (14.5 ± 4.9 vs. 19 ± 2.7 years). The models best describing the reported AAO distributions of European and USA bipolar I patients were remarkably stable. The intermediate- and late-onset subgroups had similar characteristics in the two samples. However, the theoretical AAO function differed significantly between the USA and European samples due to the higher proportion of patients in the early-onset subgroup and the lower mean age-at-onset in the USA sample.

Gender-related similarities and differences in the body distribution of grape seed flavanols in rats.

PubMed

Margalef, Maria; Pons, Zara; Iglesias-Carres, Lisard; Arola, Lluís; Muguerza, Begoña; Arola-Arnal, Anna

2016-04-01

Dietary flavanols produce beneficial health effects, and once absorbed, they are recognized as xenobiotics and undergo phase-II enzymatic detoxification. Flavanols health-promoting properties are mainly attributed to their metabolic products. This work aimed to elucidate whether rats of the opposite sex exhibited differences in the metabolism and distribution of ingested flavanols. Acute doses of grape seed polyphenols were administered to male and female rats. After 1, 2 and 4 h, plasma, liver, mesenteric white adipose tissue (MWAT), brain and hypothalamus flavanol metabolites were quantified by HPLC-MS/MS. Results indicated important sex-related quantitative differences in plasma and brain. Moreover, remarkable sex-related differences in the distributions and types of flavanol metabolites were also observed between liver and brain. This study demonstrated that sex differentially influences the metabolism and distribution of flavanols throughout the bodies of rats, which may affect the physiological bioactivities of flavanols between males and females. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Spectral Variability in the Aged Brain during Fine Motor Control

PubMed Central

Quandt, Fanny; Bönstrup, Marlene; Schulz, Robert; Timmermann, Jan E.; Zimerman, Maximo; Nolte, Guido; Hummel, Friedhelm C.

2016-01-01

Physiological aging is paralleled by a decline of fine motor skills accompanied by structural and functional alterations of the underlying brain network. Here, we aim to investigate age-related changes in the spectral distribution of neuronal oscillations during fine skilled motor function. We employ the concept of spectral entropy in order to describe the flatness and peaked-ness of a frequency spectrum to quantify changes in the spectral distribution of the oscillatory motor response in the aged brain. Electroencephalogram was recorded in elderly (n = 32) and young (n = 34) participants who performed either a cued finger movement or a pinch or a whole hand grip task with their dominant right hand. Whereas young participant showed distinct, well-defined movement-related power decreases in the alpha and upper beta band, elderly participants exhibited a flat broadband, frequency-unspecific power desynchronization. This broadband response was reflected by an increase of spectral entropy over sensorimotor and frontal areas in the aged brain. Neuronal activation patterns differed between motor tasks in the young brain, while the aged brain showed a similar activation pattern in all tasks. Moreover, we found a wider recruitment of the cortical motor network in the aged brain. The present study adds to the understanding of age-related changes of neural coding during skilled motor behavior, revealing a less predictable signal with great variability across frequencies in a wide cortical motor network in the aged brain. The increase in entropy in the aged brain could be a reflection of random noise-like activity or could represent a compensatory mechanism that serves a functional role. PMID:28066231

Selection of USSR foreign similarity regions

NASA Technical Reports Server (NTRS)

Disler, J. M. (Principal Investigator)

1982-01-01

The similarity regions in the United States and Canada were selected to parallel the conditions that affect labeling and classification accuracies in the U.S.S.R. indicator regions. In addition to climate, a significant condition that affects labeling and classification accuracies in the U.S.S.R. is the proportion of barley and wheat grown in a given region (based on sown areas). The following regions in the United States and Canada were determined to be similar to the U.S.S.R. indicator regions: (1) Montana agrophysical unit (APU) 104 corresponds to the Belorussia high barley region; (2) North Dakota and Minnesota APU 20 and secondary region southern Manitoba and Saskatchewan correspond to the Ural RSFSR barley and spring wheat region; (3) Montana APU 23 corresponds to he North Caucasus barley and winter wheat region. Selection criteria included climates, crop type, crop distribution, growth cycles, field sizes, and field shapes.

Quantifying Similarity and Distance Measures for Vector-Based Datasets: Histograms, Signals, and Probability Distribution Functions

DTIC Science & Technology

2017-02-01

note, a number of different measures implemented in both MATLAB and Python as functions are used to quantify similarity/distance between 2 vector-based...this technical note are widely used and may have an important role when computing the distance and similarity of large datasets and when considering high...throughput processes. In this technical note, a number of different measures implemented in both MAT- LAB and Python as functions are used to

Self-similarity of waiting times in fracture systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Niccolini, G.; Bosia, F.; Carpinteri, A.

2009-08-15

Experimental and numerical results are presented for a fracture experiment carried out on a fiber-reinforced element under flexural loading, and a statistical analysis is performed for acoustic emission waiting-time distributions. By an optimization procedure, a recently proposed scaling law describing these distributions for different event magnitude scales is confirmed by both experimental and numerical data, thus reinforcing the idea that fracture of heterogeneous materials has scaling properties similar to those found for earthquakes. Analysis of the different scaling parameters obtained for experimental and numerical data leads us to formulate the hypothesis that the type of scaling function obtained depends onmore » the level of correlation among fracture events in the system.« less

Score distribution of the scoliosis research society-22 questionnaire in subgroups of patients of all ages with idiopathic scoliosis.

PubMed

Parent, Eric C; Dang, Rohan; Hill, Doug; Mahood, Jim; Moreau, Marc; Raso, Jim; Lou, Edmond

2010-03-01

Cross-sectional measurement study. To analyze the score distribution of the Scoliosis Research Society (SRS)-22 questionnaire domains and items for patients with idiopathic scoliosis (IS) of all ages. Scoliosis-related quality-of-life questionnaires have demonstrated high ceiling effects in younger patients. However, the score distribution has not been examined thoroughly in other clinically relevant IS subgroups. The SRS-22 was completed by 173 females with IS. The proportions of ceiling effects, floor effects, of patients scoring greater than or equal to 4 out of 5 and the box plots of the score distribution for each domain and item were compared between subgroups. Subgroups were formed based on age (k = 4), management (k = 6), curve severity (k = 3), and curve type (k = 4). Domain ceiling effects varied between 0% and 23.1%. Domain floor effects were observed only for Self-image (<7%) and Satisfaction (<12%). Only Pain and Satisfaction showed moderate (>20%) ceiling effects. Ceiling effects for Pain and Mental Health decreased with increasing age (P < 0.05). Pain ceiling effects decreased and Satisfaction ceiling effects increased from least to most invasive management (P < 0.05), but no differences were found among Cobb severity or curve types subgroups. Of the 22 items, 9 had major (>or=50%) ceiling effects and 11 had moderate ceiling effects. Most subgroups (14/16) had 4 to 6 items with major ceiling effects. The following items had major ceiling effects in the majority of subgroups: Function, 9 and 15; Pain, 11 and 17; and Self-image, 14. Most SRS-22 domains had acceptable levels of ceiling effects (<20%) in the majority of the subgroups examined. However, more sensitive measurements may be needed to supplement the SRS-22 in assessing Pain in patients below 18 years or Satisfaction after surgery.

Alcohol-related expectancies in adults and adolescents: Similarities and disparities.

PubMed

Monk, Rebecca L; Heim, Derek

2016-03-02

This study aimed to contrast student and not student outcome expectancies, and explore the diversity of alcohol-related cognitions within a wider student sample. Participants (n=549) were college students (higher education-typically aged 15-18 years), university students (further education-typically aged 18-22 years) and business people (white collar professionals <50 years) who completed questionnaires in their place of work or education. Overall positive expectancies were higher in the college students than in the business or university samples. However, not all expectancy subcategories followed this pattern. Participant groups of similar age were therefore alike in some aspects of their alcohol-related cognitions but different in others. Similarly, participant groups whom are divergent in age appeared to be alike in some of their alcohol-related cognitions, such as tension reduction expectancies. Research often homogenises students as a specific sub-set of the population, this paper hi-lights that this may be an over-simplification. Furthermore, the largely exclusive focus on student groups within research in this area may also be an oversight, given the diversity of the findings demonstrated between these groups.

Similar BCL-X but different BCL-2 levels in the two age groups of north African nasopharyngeal carcinomas.

PubMed

Khabir, Abdelmajid; Ghorbel, Abdelmoneem; Daoud, Jamel; Frikha, Mounir; Drira, Mohamed Mokhtar; Laplanche, Agnès; Busson, Pierre; Jlidi, Rachid

2003-01-01

Nasopharyngeal carcinomas (NPCs) are consistently associated with the Epstein-Barr virus (EBV). As Bcl-2 and Bcl-X are co-expressed in EBV-transformed B-lymphocytes, we attempted to determine their status in malignant NPC cells. A retrospective series of 100 NPC specimens from untreated Tunisian patients was investigated by immuno-histochemistry. Twenty seven of the patients were below 30 years old and therefore classified in the "juvenile" form of north African NPCs. Bcl-2 and Bcl-X expression was assessed semi-quantitatively using a score based on the percentage of positive cells and staining intensity. Intense Bcl-X expression was detected in malignant cells of 100% biopsy samples with similar scores for patients below 30 years or those aged 30 or over. Bcl-2 was detected in 89% biopsies but its expression differed considerably between the samples. The average Bcl-2 score was much lower for patients under 30 years (4.4+/-1.5 compared to 6.5+/-2 for older patients; P<10(-6)). Multivariate analysis demonstrated that no other clinical parameter, except the primary tumor size, was correlated to the Bcl-2 score. Bcl-X and Bcl-2 are co-expressed in 89% of NPCs whereas their expression is mutually exclusive in other head and neck carcinomas (particularly squamous cell carcinomas, SCC). The constantly high expression of Bcl-X is consistent with it being induced by the EBV protein Epstein-Barr nuclear antigen 1 (EBNA1), as recently reported in a murine model. The contrasted levels of Bcl-2 expression in the two age groups strengthen the hypothesis that these clinical forms result from distinct oncogenic mechanisms.

Low birth weight,very low birth weight rates and gestational age-specific birth weight distribution of korean newborn infants.

PubMed

Shin, Son-Moon; Chang, Young-Pyo; Lee, Eun-Sil; Lee, Young-Ah; Son, Dong-Woo; Kim, Min-Hee; Choi, Young-Ryoon

2005-04-01

To obtain the low birth weight (LBW) rate, the very low birth weight (VLBW) rate, and gestational age (GA)-specific birth weight distribution based on a large population in Korea, we collected and analyzed the birth data of 108,486 live births with GA greater than 23 weeks for 1 yr from 1 January to 31 December 2001, from 75 hospitals and clinics located in Korea. These data included birth weight, GA, gender of the infants, delivery type, maternal age, and the presence of multiple pregnancy. The mean birth weight and GA of a crude population are 3,188 +/-518 g and 38.7+/-2.1 weeks, respectively. The LBW and the VLBW rates are 7.2% and 1.4%, respectively. The preterm birth rate (less than 37 completed weeks of gestation) is 8.4% and the very preterm birth rate (less than 32 completed weeks of gestation) is 0.7%. The mean birth weights for female infants, multiple births, and births delivered by cesarean section were lower than those for male, singletons, and births delivered vaginally. The risk of delivering LBW or VLBW infant was higher for the teenagers and the older women (aged 35 yr and more). We have also obtained the percentile distribution of GA-specific birth weight in infants over 23 weeks of gestation.

Distribution of ghrelin-producing cells in the gastrointestinal tract of pigs at different ages.

PubMed

Vitari, Francesca; Di Giancamillo, Alessia; Deponti, Daniela; Carollo, Valentina; Domeneghini, Cinzia

2012-03-01

Ghrelin is involved in many biological processes, ranging from appetite regulation and the release of growth hormone to the regulation of gastrointestinal motility and secretion processes. Ghrelin expression is not homogenously distributed throughout the gastrointestinal tract; expression is species-specific and can also depend on the animal age. This study was performed to investigate ghrelin immunolocalization in the gastrointestinal tract of pigs at different ages: 1 day (birth), 28 days (weaning), 2 months, 4 months, and 7 months (pre-puberty). Tissue samples were collected along the entire gastrointestinal tract and were examined by immunohistochemistry and double-immunofluorescence. Histometry was performed by counting the number of endocrine ghrelin immunopositive cells in the gastrointestinal mucosa. Ghrelin was found to be present along the swine alimentary canal from the stomach to the caecum. In all regions of the alimentary canal of the animals studied, ghrelin-immunoreactive (IR) cells co-localized with chromogranin-A and were therefore identified as endocrine cells. In the gastric fundus, ghrelin-immunoreactivity was partially detected in co-localization with H-K-adenosine triphosphatase and pepsinogen. Ghrelin-IR endocrine cells were abundant in the oxyntic mucosa but less present in the small intestine and rare in the large intestine. The cell density of the ghrelin-IR endocrine cells was lowest in the oxyntic mucosa of 1-day-old pigs. We can conclude that gastric ghrelin expression is not related merely to age but could also potentially be influenced by food intake.

Effects of healthy aging and early stage dementia of the Alzheimer's type on components of response time distributions in three attention tasks.

PubMed

Tse, Chi-Shing; Balota, David A; Yap, Melvin J; Duchek, Janet M; McCabe, David P

2010-05-01

The characteristics of response time (RT) distributions beyond measures of central tendency were explored in 3 attention tasks across groups of young adults, healthy older adults, and individuals with very mild dementia of the Alzheimer's type (DAT). Participants were administered computerized Stroop, Simon, and switching tasks, along with psychometric tasks that tap various cognitive abilities and a standard personality inventory (NEO-FFI). Ex-Gaussian (and Vincentile) analyses were used to capture the characteristics of the RT distributions for each participant across the 3 tasks, which afforded 3 components: mu and sigma (mean and standard deviation of the modal portion of the distribution) and tau (the positive tail of the distribution). The results indicated that across all 3 attention tasks, healthy aging produced large changes in the central tendency mu parameter of the distribution along with some change in sigma and tau (mean etap(2) = .17, .08, and .04, respectively). In contrast, early stage DAT primarily produced an increase in the tau component (mean etap(2) = .06). tau was also correlated with the psychometric measures of episodic/semantic memory, working memory, and processing speed, and with the personality traits of neuroticism and conscientiousness. Structural equation modeling indicated a unique relation between a latent tau construct (-.90), as opposed to sigma (-.09) and mu constructs (.24), with working memory measures. The results suggest a critical role of attentional control systems in discriminating healthy aging from early stage DAT and the utility of RT distribution analyses to better specify the nature of such change.

Female breast cancer incidence among Asian and Western populations: more similar than expected.

PubMed

Sung, Hyuna; Rosenberg, Philip S; Chen, Wan-Qing; Hartman, Mikael; Lim, Wei-Yen; Chia, Kee Seng; Wai-Kong Mang, Oscar; Chiang, Chun-Ju; Kang, Daehee; Ngan, Roger Kai-Cheong; Tse, Lap Ah; Anderson, William F; Yang, Xiaohong R

2015-07-01

Previous reports suggested that female breast cancer is associated with earlier ages at onset among Asian than Western populations. However, most studies utilized cross-sectional analyses that may be confounded by calendar-period and/or birth cohort effects. We, therefore, considered a longitudinal (forward-looking) approach adjusted for calendar-period changes and conditioned upon birth cohort. Invasive female breast cancer data (1988-2009) were obtained from cancer registries in China, Hong Kong, South Korea, Taiwan, Singapore, and the United States. Age-period-cohort models were used to extrapolate longitudinal age-specific incidence rates for the 1920, 1944, and 1970 birth cohorts. Cross-sectional age-specific incidence rates rose continuously until age 80 years among US white women, but plateaued or decreased after age 50 years among Asian women. In contrast, longitudinal age-specific rates were proportional (similar) among all Asian countries and the United States with incidence rates rising continuously until age 80 years. The extrapolated estimates for the most recent cohorts in some Asian countries actually showed later ages at onset than in the United States. Additionally, over successive birth cohorts, the incidence rate ratios (IRRs) for the longitudinal curves converged (narrowed) between Asian and US white women. Similar longitudinal age-specific incidence rates along with converging IRRs indicate that the age effects for invasive breast cancer are more similar among Asian and Western populations than might be expected from a solely cross-sectional analysis. Indeed, the Asian breast cancer rates in recent generations are even surpassing the historically high rates in the United States, highlighting an urgent need for efficient prevention and treatment strategies among Asian populations. Published by Oxford University Press 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Statistical self-similarity of width function maxima with implications to floods

USGS Publications Warehouse

Veitzer, S.A.; Gupta, V.K.

2001-01-01

Recently a new theory of random self-similar river networks, called the RSN model, was introduced to explain empirical observations regarding the scaling properties of distributions of various topologic and geometric variables in natural basins. The RSN model predicts that such variables exhibit statistical simple scaling, when indexed by Horton-Strahler order. The average side tributary structure of RSN networks also exhibits Tokunaga-type self-similarity which is widely observed in nature. We examine the scaling structure of distributions of the maximum of the width function for RSNs for nested, complete Strahler basins by performing ensemble simulations. The maximum of the width function exhibits distributional simple scaling, when indexed by Horton-Strahler order, for both RSNs and natural river networks extracted from digital elevation models (DEMs). We also test a powerlaw relationship between Horton ratios for the maximum of the width function and drainage areas. These results represent first steps in formulating a comprehensive physical statistical theory of floods at multiple space-time scales for RSNs as discrete hierarchical branching structures. ?? 2001 Published by Elsevier Science Ltd.

Shifts in depth distributions of alewives, rainbow smelt, and age-2 lake trout in southern Lake Ontario following establishment of Dreissenids

USGS Publications Warehouse

O'Gorman, Robert; Elrod, Joseph H.; Owens, Randall W.; Schneider, Clifford P.; Eckert, Thomas H.; Lantry, Brian F.

2000-01-01

In the mid-1990s, biologists conducting assessments of fish stocks in Lake Ontario reported finding alewives Alosa pseudoharengus, rainbow smelt Osmerus mordax, and juvenile lake trout Salvelinus namaycush at greater depths than in the mid-1980s. To determine if depth distributions shifted coincident with the early 1990s colonization of Lake Ontario by exotic Dreissena mussels, we calculated mean depth of capture for each of the three species during trawl surveys conducted annually during 1978–1997 and examined the means for significant deviations from established patterns. We found that mean capture depth of alewives, rainbow smelt, and age-2 lake trout shifted deeper during the build up of the dreissenid population in Lake Ontario but that timing of the shift varied among seasons and species. Depth shifts occurred first for rainbow smelt and age-2 lake trout in June 1991. In 1992, alewives shifted deeper in June followed by age-2 lake trout in July–August. Finally, in 1993 and 1994, the distribution of lake trout and alewives shifted in April–May. Reasons why the three fishes moved to deeper water are not clear, but changes in distribution were not linked to temperature. Mean temperature of capture after the depth shift was significantly lower than before the depth shift except for alewives in April–May. Movement of alewives, rainbow smelt, and age-2 lake trout to colder, deeper water has the potential to alter growth and reproduction schedules by exposing the fish to different temperature regimes and to alter the food chain, increasing predation on Mysis relicta in deep water and decreasing alewife predation on lake trout fry over nearshore spawning grounds in spring.

Chirped self-similar waves for quadratic-cubic nonlinear Schrödinger equation

NASA Astrophysics Data System (ADS)

Pal, Ritu; Loomba, Shally; Kumar, C. N.

2017-12-01

We have constructed analytical self-similar wave solutions for quadratic-cubic Nonlinear Schrödinger equation (QC-NLSE) by means of similarity transformation method. Then, we have investigated the role of chirping on these self-similar waves as they propagate through the tapered graded index waveguide. We have revealed that the chirping leads to interesting features and allows us to control the propagation of self-similar waves. This has been demonstrated for two cases (i) periodically distributed system and (ii) constant choice of system parameters. We expect our results to be useful in designing high performance optical devices.

Age Differences in Loneliness from Late Adolescence to Oldest Old Age

ERIC Educational Resources Information Center

Luhmann, Maike; Hawkley, Louise C.

2016-01-01

Contrary to common stereotypes, loneliness is not restricted to old age but can occur at any life stage. In this study, we used data from a large, nationally representative German study (N = 16,132) to describe and explain age differences in loneliness from late adolescence to oldest old age. The age distribution of loneliness followed a complex…

Predictive value of low BMD for 1-year fracture outcomes is similar for postmenopausal women ages 50-64 and 65 and Older: results from the National Osteoporosis Risk Assessment (NORA).

PubMed

Siris, Ethel S; Brenneman, Susan K; Miller, Paul D; Barrett-Connor, Elizabeth; Chen, Ya-Ting; Sherwood, Louis M; Abbott, Thomas A

2004-08-01

The relationship of low bone mass and fracture in younger postmenopausal women has not been extensively studied. In a large cohort of postmenopausal women > or =50 years of age, we found the relationship of BMD measured at peripheral sites and subsequent 1-year fracture risk to be similar between women <65 and those > or =65 years of age. Low bone mass and fractures are prevalent in older postmenopausal women. However, the frequency of low bone mass and fracture in younger postmenopausal women has not been studied extensively. There are very limited data regarding the association between BMD measurements and fractures in postmenopausal women who are between the ages of 50 and 64. In the National Osteoporosis Risk Assessment (NORA) we studied the frequency of low bone mass and its association with fracture in women 50-64 years of age in comparison with women > or =65 of age. NORA enrolled 200,160 postmenopausal women > or =50 years of age who had no prior diagnosis of osteoporosis. Baseline BMD was measured at the heel, forearm, or finger. A 1-year follow-up survey requesting incident fractures since baseline was completed by 163,935 women, 87,594 (53%) of whom were 50-64 years of age. The association between BMD and fracture was assessed using logistic regression, adjusted for important covariates. Thirty-one percent of women 50-64 years of age had low bone mass (T scores < or = -1.0) compared to 62% of women > or =65 years of age. During the first year of follow-up, 2440 women reported fractures of wrist/forearm, rib, spine, or hip, including 440 hip fractures. Nine hundred four women 50-64 years of age reported fractures, including 86 hip fractures, accounting for 37% of fractures and 20% of hip fractures reported in the entire NORA cohort. Relative risk for osteoporotic fracture was 1.5 for each SD decrease in BMD for both the younger and older groups of women. Low BMD in younger postmenopausal women 50-64 years of age showed a 1-year relative risk of fracture

Caffeine delays oocyte aging and maintains the quality of aged oocytes safely in mouse.

PubMed

Zhang, Xia; Liu, Xiaoyan; Chen, Li; Wu, Dan-Ya; Nie, Zheng-Wen; Gao, Ying-Ying; Miao, Yi-Liang

2017-03-28

Caffeine, as an oocyte aging inhibitor, was used in many different species to control or delay oocyte aging. However, the safety of caffeine and developmental competence of aged oocytes inhibited by caffeine has not been studied systematically. So we detected the spindle morphology, distribution of cortical granules, zona pellucida hardening and pronucleus formation to assess oocyte quality of caffeine treated oocytes. We found that aged oocytes treated by caffeine maintained weak susceptibility to activating stimuli and regained normal competent after aged further 6 hr. Caffeine maintained the spindle morphology, changed cortical granules distribution of aged oocytes and could not prevent zona pellucida hardening. Furthermore, caffeine increased pronucleus formation of aged oocytes and decreased fragmentation after fertilization. These results suggested that caffeine could maintain the quality of aged oocytes safely in mouse.

The prevalence of age-related maculopathy by geographic region and ethnicity.

PubMed

Klein, R; Klein, B E; Cruickshanks, K J

1999-05-01

The prevalence of age-related maculopathy (ARM) varies considerably in different locations and racial/ethnic groups around the world. At present there are insufficient data to determine whether it is likely that these differences in prevalence, especially for the early forms of ARM are due to variations in genetic and environmental factors or due to variations in age of the cohorts and methods used to ascertain and define ARM. In three population-based studies of whites living in Beaver Dam, Wisconsin, Blue Mountains, Australia, and Rotterdam, The Netherlands, in which similar methods of ascertainment and classification were used to detect and define ARM, late ARM was present in 1.2%, 1.4%, and 1.2% of the population less than 86 years of age, respectively. While data from clinical studies suggest that late ARM associated with choroidal neovascularization is rare in blacks compared with whites, some epidemiological studies suggest that late ARM may be similar in blacks and whites. There are still too few data from various ethnic/racial groups around the world and too few population-based data in older Hispanic and Asian populations to make meaningful comparisons. There is a need for further research into the distribution of ARM and its possible causes using similar methodologies to ascertain and define the disease. Further insights will be gained when genotypes associated with ARM are discovered.

Consumption of Milk Protein or Whey Protein Results in a Similar Increase in Muscle Protein Synthesis in Middle Aged Men

PubMed Central

Mitchell, Cameron J.; McGregor, Robin A.; D’Souza, Randall F.; Thorstensen, Eric B.; Markworth, James F.; Fanning, Aaron C.; Poppitt, Sally D.; Cameron-Smith, David

2015-01-01

The differential ability of various milk protein fractions to stimulate muscle protein synthesis (MPS) has been previously described, with whey protein generally considered to be superior to other fractions. However, the relative ability of a whole milk protein to stimulate MPS has not been compared to whey. Sixteen healthy middle-aged males ingested either 20 g of milk protein (n = 8) or whey protein (n = 8) while undergoing a primed constant infusion of ring 13C6 phenylalanine. Muscle biopsies were obtained 120 min prior to consumption of the protein and 90 and 210 min afterwards. Resting myofibrillar fractional synthetic rates (FSR) were 0.019% ± 0.009% and 0.021% ± 0.018% h−1 in the milk and whey groups respectively. For the first 90 min after protein ingestion the FSR increased (p < 0.001) to 0.057% ± 0.018% and 0.052% ± 0.024% h−1 in the milk and whey groups respectively with no difference between groups (p = 0.810). FSR returned to baseline in both groups between 90 and 210 min after protein ingestion. Despite evidence of increased rate of digestion and leucine availability following the ingestion of whey protein, there was similar activation of MPS in middle-aged men with either 20 g of milk protein or whey protein. PMID:26506377

Evaluating gender similarities and differences using metasynthesis.

PubMed

Zell, Ethan; Krizan, Zlatan; Teeter, Sabrina R

2015-01-01

Despite the common lay assumption that males and females are profoundly different, Hyde (2005) used data from 46 meta-analyses to demonstrate that males and females are highly similar. Nonetheless, the gender similarities hypothesis has remained controversial. Since Hyde's provocative report, there has been an explosion of meta-analytic interest in psychological gender differences. We utilized this enormous collection of 106 meta-analyses and 386 individual meta-analytic effects to reevaluate the gender similarities hypothesis. Furthermore, we employed a novel data-analytic approach called metasynthesis (Zell & Krizan, 2014) to estimate the average difference between males and females and to explore moderators of gender differences. The average, absolute difference between males and females across domains was relatively small (d = 0.21, SD = 0.14), with the majority of effects being either small (46%) or very small (39%). Magnitude of differences fluctuated somewhat as a function of the psychological domain (e.g., cognitive variables, social and personality variables, well-being), but remained largely constant across age, culture, and generations. These findings provide compelling support for the gender similarities hypothesis, but also underscore conditions under which gender differences are most pronounced. PsycINFO Database Record (c) 2015 APA, all rights reserved.

The impact of bereaved parents' perceived grief similarity on relationship satisfaction.

PubMed

Buyukcan-Tetik, Asuman; Finkenauer, Catrin; Schut, Henk; Stroebe, Margaret; Stroebe, Wolfgang

2017-06-01

The present research focused on bereaved parents' perceived grief similarity, and aimed to investigate the concurrent and longitudinal effects of the perceptions that the partner has less, equal, or more grief intensity than oneself on relationship satisfaction. Participants of our longitudinal study were 229 heterosexual bereaved Dutch couples who completed questionnaires 6, 13, and 20 months after the loss of their child. Average age of participants was 40.7 (SD = 9.5). Across 3 study waves, participants' perceived grief similarity and relationship satisfaction were assessed. To control for their effects, own grief level, child's gender, expectedness of loss, parent's age, parent's gender, and time were also included in the analyses. Consistent with the hypotheses, cross-sectional results revealed that bereaved parents who perceived dissimilar levels of grief (less or more grief) had lower relationship satisfaction than bereaved parents who perceived similar levels of grief. This effect remained significant controlling for the effects of possible confounding variables and actual similarity in grief between partners. We also found that perceived grief similarity at the first study wave was related to the highest level of relationship satisfaction at the second study wave. Moreover, results showed that perceived grief similarity was associated with a higher level in partner's relationship satisfaction. Results are discussed considering the comparison and similarity in grief across bereaved partners after child loss. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Earthquake detection through computationally efficient similarity search

PubMed Central

Yoon, Clara E.; O’Reilly, Ossian; Bergen, Karianne J.; Beroza, Gregory C.

2015-01-01

Seismology is experiencing rapid growth in the quantity of data, which has outpaced the development of processing algorithms. Earthquake detection—identification of seismic events in continuous data—is a fundamental operation for observational seismology. We developed an efficient method to detect earthquakes using waveform similarity that overcomes the disadvantages of existing detection methods. Our method, called Fingerprint And Similarity Thresholding (FAST), can analyze a week of continuous seismic waveform data in less than 2 hours, or 140 times faster than autocorrelation. FAST adapts a data mining algorithm, originally designed to identify similar audio clips within large databases; it first creates compact “fingerprints” of waveforms by extracting key discriminative features, then groups similar fingerprints together within a database to facilitate fast, scalable search for similar fingerprint pairs, and finally generates a list of earthquake detections. FAST detected most (21 of 24) cataloged earthquakes and 68 uncataloged earthquakes in 1 week of continuous data from a station located near the Calaveras Fault in central California, achieving detection performance comparable to that of autocorrelation, with some additional false detections. FAST is expected to realize its full potential when applied to extremely long duration data sets over a distributed network of seismic stations. The widespread application of FAST has the potential to aid in the discovery of unexpected seismic signals, improve seismic monitoring, and promote a greater understanding of a variety of earthquake processes. PMID:26665176

δ-Similar Elimination to Enhance Search Performance of Multiobjective Evolutionary Algorithms

NASA Astrophysics Data System (ADS)

Aguirre, Hernán; Sato, Masahiko; Tanaka, Kiyoshi

In this paper, we propose δ-similar elimination to improve the search performance of multiobjective evolutionary algorithms in combinatorial optimization problems. This method eliminates similar individuals in objective space to fairly distribute selection among the different regions of the instantaneous Pareto front. We investigate four eliminating methods analyzing their effects using NSGA-II. In addition, we compare the search performance of NSGA-II enhanced by our method and NSGA-II enhanced by controlled elitism.

Wound healing delays in α-Klotho-deficient mice that have skin appearance similar to that in aged humans - Study of delayed wound healing mechanism.

PubMed

Yamauchi, Makoto; Hirohashi, Yoshihiko; Torigoe, Toshihiko; Matsumoto, Yoshitaka; Yamashita, Ken; Kayama, Musashi; Sato, Noriyuki; Yotsuyanagi, Takatoshi

2016-05-13

Skin atrophy and delayed wound healing are observed in aged humans; however, the molecular mechanism are still elusive. The aim of this study was to analyze the molecular mechanisms of delayed wound healing by aging using α-Klotho-deficient (kl/kl) mice, which have phenotypes similar to those of aged humans. The kl/kl mice showed delayed wound healing and impaired granulation formation compared with those in wild-type (WT) mice. The skin graft experiments revealed that delayed wound healing depends on humoral factors, but not on kl/kl skin tissue. The mRNA expression levels of cytokines related to acute inflammation including IL-1β, IL-6 and TNF-α were higher in wound lesions of kl/kl mice compared with the levels in WT mice by RT-PCR analysis. LPS-induced TNF-α production model using spleen cells revealed that TNF-α production was significantly increased in the presence of FGF23. Thus, higher levels of FGF23 in kl/kl mouse may have a role to increase TNF-α production in would lesion independently of α-Klotho protein, and impair granulation formation and delay wound healing. Copyright © 2016 Elsevier Inc. All rights reserved.

Professional ballet dancers have a similar prevalence of articular cartilage defects compared to age- and sex-matched non-dancing athletes.

PubMed

Mayes, Susan; Ferris, April-Rose; Smith, Peter; Garnham, Andrew; Cook, Jill

2016-12-01

Ballet exposes the hip joint to repetitive loading in extreme ranges of movement and may predispose a dancer to pain and osteoarthritis (OA). The aims of this study were to compare the prevalence of cartilage defects in professional ballet dancers and athletes and to determine the relationship of clinical signs and symptoms. Forty-nine male and female, current and retired professional ballet dancers and 49 age- and sex-matched non-dancing athletes completed hip pain questionnaires, including the Copenhagen Hip and Groin Outcome Score (HAGOS), and underwent hip range of movement (ROM) testing and 3-Tesla magnetic resonance imaging to score cartilage defects (no defect, grade 1: focal partial defect and grade 2: diffuse or full thickness defect). Thirty (61 %) dancers and 27 (55 %) athletes had cartilage defects (p = 0.54). The frequency of grade 1 and 2 cartilage defects did not differ between dancers and athletes (p = 0.83). The frequency of cartilage defects was similar in male and female dancers (p = 0.34), and male and female athletes (p = 0.24). Cartilage defects were not related to history of hip pain (p = 0.34), HAGOS pain (p = 0.14), sports/rec (p = 0.15) scores or hip internal rotation ≤20° (p > 0.01). Cartilage defects were related to age in male dancers (p = 0.002). Ballet dancers do not appear to be at a greater risk of cartilage injury compared to non-dancing athletes. Male dancers develop cartilage defects at an earlier age than athletes and female dancers. Cartilage defects were not related to clinical signs and symptoms; thus, prospective studies are required to determine which cartilage defects progress to symptomatic hip OA.

Advantageous developmental outcomes of advancing paternal age

PubMed Central

Janecka, M; Rijsdijk, F; Rai, D; Modabbernia, A; Reichenberg, A

2017-01-01

Advanced paternal age (APA) at conception has been associated with negative outcomes in offspring, raising concerns about increasing age at fatherhood. Evidence from evolutionary and psychological research, however, suggests possible link between APA and a phenotypic advantage. We defined such advantage as educational success, which is positively associated with future socioeconomic status. We hypothesised that high IQ, strong focus on the subject of interest and little concern about ‘fitting in’ will be associated with such success. Although these traits are continuously distributed in the population, they cluster together in so-called ‘geeks’. We used these measures to compute a ‘geek index’ (GI), and showed it to be strongly predictive of future academic attainment, beyond the independent contribution of the individual traits. GI was associated with paternal age in male offspring only, and mediated the positive effects of APA on education outcomes, in a similar sexually dimorphic manner. The association between paternal age and GI was partly mediated by genetic factors not correlated with age at fatherhood, suggesting contribution of de novo factors to the ‘geeky’ phenotype. Our study sheds new light on the multifaceted nature of the APA effects and explores the intricate links between APA, autism and talent. PMID:28632201

Ectomycorrhizal Fungal Communities in Urban Parks Are Similar to Those in Natural Forests but Shaped by Vegetation and Park Age

PubMed Central

Liu, Xinxin; Kotze, D. Johan; Jumpponen, Ari; Francini, Gaia; Setälä, Heikki

2017-01-01

ABSTRACT Ectomycorrhizal (ECM) fungi are important mutualists for the growth and health of most boreal trees. Forest age and its host species composition can impact the composition of ECM fungal communities. Although plentiful empirical data exist for forested environments, the effects of established vegetation and its successional trajectories on ECM fungi in urban greenspaces remain poorly understood. We analyzed ECM fungi in 5 control forests and 41 urban parks of two plant functional groups (conifer and broadleaf trees) and in three age categories (10, ∼50, and >100 years old) in southern Finland. Our results show that although ECM fungal richness was marginally greater in forests than in urban parks, urban parks still hosted rich and diverse ECM fungal communities. ECM fungal community composition differed between the two habitats but was driven by taxon rank order reordering, as key ECM fungal taxa remained largely the same. In parks, the ECM communities differed between conifer and broadleaf trees. The successional trajectories of ECM fungi, as inferred in relation to the time since park construction, differed among the conifers and broadleaf trees: the ECM fungal communities changed over time under the conifers, whereas communities under broadleaf trees provided no evidence for such age-related effects. Our data show that plant-ECM fungus interactions in urban parks, in spite of being constructed environments, are surprisingly similar in richness to those in natural forests. This suggests that the presence of host trees, rather than soil characteristics or even disturbance regime of the system, determine ECM fungal community structure and diversity. IMPORTANCE In urban environments, soil and trees improve environmental quality and provide essential ecosystem services. ECM fungi enhance plant growth and performance, increasing plant nutrient acquisition and protecting plants against toxic compounds. Recent evidence indicates that soil-inhabiting fungal

Ectomycorrhizal Fungal Communities in Urban Parks Are Similar to Those in Natural Forests but Shaped by Vegetation and Park Age.

PubMed

Hui, Nan; Liu, Xinxin; Kotze, D Johan; Jumpponen, Ari; Francini, Gaia; Setälä, Heikki

2017-12-01

Ectomycorrhizal (ECM) fungi are important mutualists for the growth and health of most boreal trees. Forest age and its host species composition can impact the composition of ECM fungal communities. Although plentiful empirical data exist for forested environments, the effects of established vegetation and its successional trajectories on ECM fungi in urban greenspaces remain poorly understood. We analyzed ECM fungi in 5 control forests and 41 urban parks of two plant functional groups (conifer and broadleaf trees) and in three age categories (10, ∼50, and >100 years old) in southern Finland. Our results show that although ECM fungal richness was marginally greater in forests than in urban parks, urban parks still hosted rich and diverse ECM fungal communities. ECM fungal community composition differed between the two habitats but was driven by taxon rank order reordering, as key ECM fungal taxa remained largely the same. In parks, the ECM communities differed between conifer and broadleaf trees. The successional trajectories of ECM fungi, as inferred in relation to the time since park construction, differed among the conifers and broadleaf trees: the ECM fungal communities changed over time under the conifers, whereas communities under broadleaf trees provided no evidence for such age-related effects. Our data show that plant-ECM fungus interactions in urban parks, in spite of being constructed environments, are surprisingly similar in richness to those in natural forests. This suggests that the presence of host trees, rather than soil characteristics or even disturbance regime of the system, determine ECM fungal community structure and diversity. IMPORTANCE In urban environments, soil and trees improve environmental quality and provide essential ecosystem services. ECM fungi enhance plant growth and performance, increasing plant nutrient acquisition and protecting plants against toxic compounds. Recent evidence indicates that soil-inhabiting fungal communities

Equilibrium population dynamics when mating is by mutual choice based on age.

PubMed

Alpern, Steve; Katrantzi, Ioanna; Ramsey, David

2014-06-01

We consider a steady state model of mutual mate choice in which an individual's mate preferences depend on his/her age, and the preferences are over the ages of prospective mates of the opposite sex. We present a discrete time (and age) model corresponding to successive mating seasons. Males are fertile for m periods (corresponding to 'age' i=1 to m) and females for n≤m periods (they have ages j=1 to n), which is all that distinguishes the sexes. Although we can deal with arbitrary preferences, we concentrate on a simple fertility model where the common utility to a male age i and female age j who mate is the number K=min(m-i+1,n-j+1) of future periods of joint fertility. The incoming sex ratio R of age 1 males to age 1 females is given exogenously. In each period individuals are randomly (non assortatively) matched and form a mated couple by mutual consent; otherwise they go into the next period unmated and older. We derive properties of equilibrium threshold acceptance strategies and establish the existence of time-invariant age distributions. Our methods determine the age distribution of couples at marriage (mating) and the population sex ratio (OSR) at equilibrium. Since this can be determined empirically in a population, our model can be used to rule out most systems of age preferences (those not consistent with the observed distribution). This extends earlier models of mutual choice with one dimensional types of Alpern and Reyniers [1999. Strategic mating with homotypic preferences. J. Theor. Biol. 198, 71-88; 2005. Strategic mating with common preferences. J. Theor. Biol. 237, 337-354] where individuals sought, respectively, individuals with similar or high types, but in those models an individual's type was fixed over time. Under the simple fertility model, at equilibrium the maximum age of an acceptable partner is increasing in the age of the searcher. Our results relate to discussions in the literature regarding optimal parental age differences, age

Central pressures and central hemodynamic values in white coat hypertensives are closer to those of normotensives than to those of controlled hypertensives for similar age, gender, and 24-h and nocturnal blood pressures.

PubMed

Almeida, Joana; Monteiro, José; Silva, José A; Bertoquini, Susana; Polónia, Jorge

2016-11-01

There is disagreement whether white coat hypertensives (WCH) have different hemodynamic and structural characteristics compared to normotensives (NT) and hypertensives (HT). We compared cardiovascular prognostic markers (pulse wave velocity [PWV] and aortic stiffness index [ASI]) and data on central hemodynamics and central pressures (augmentation index [AIx], augmentation pressure [AugP] and pulse pressure amplification [PPA]) from aortic pulse wave analysis between NT (n=175), WCH (n=315) and treated HT (n=691), all with 24-h blood pressure (BP) <130/80 and nocturnal BP <120/70 mmHg after matching for age, gender, body mass index (BMI) and and nocturnal BP. The groups were also compared separately in terms of 24-h systolic BP <120 mmHg and 120-129 mmHg. The percentage of non-dippers was 40.1% in NT, 34.5% in WCH and 38.3 in HT. For similar 24-h and nocturnal systolic BP (NT 109/64±7/5, WCH 110/66±7/6, HT 109/64±7/5 mmHg), aortic stiffness was greater in HT (n=691, PWV 10.8±2.6 m/s and ASI 0.33±0.16, p<0.01) than in WCH (n=316, PWV 9.7±2.4 m/s and ASI 0.28±0.17) and NT (n=175, PWV 9.5±2.0 m/s and ASI 0.29±0.15); AugP and AIx were higher (p<0.01) in HT (13.9±8.2 and 29.6±12.6 mmHg) than in WCH (11.5±8.5 mmHg and 24.9±15.2) and NT (11.0±6.4 mmHg and 26.6±11.5). PPA was lower (p<0.01) in HT (11.3±5.5 mmHg) than in WCH (13.2±7.1 mmHg) and in NT (12.4±4.9 mmHg). The findings were similar when the 24-h systolic BP <120 mmHg and 120-129 mmHg subgroups were analyzed separately. Our data suggest that for similar age, gender distribution, BMI, and 24-h and nocturnal BP, aortic stiffness, central aortic pressures and wave reflection in WCH are closer to those of NT than to those with treated HT. This supports the idea that white coat hypertension may be a more benign condition than treated hypertension for similar 24-h and particularly nocturnal BP levels. Copyright © 2016 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All

Age and height distribution of holocene transgressive deposits in eastern North Island, New Zealand

USGS Publications Warehouse

Ota, Y.; Berryman, K.R.; Hull, A.G.; Miyauchi, T.; Iso, N.

1988-01-01

Holocene transgressive deposits are frequently exposed near the present-day coastline of the study area along eastern North Island, New Zealand. They occur in sites of former estuaries that were filled during the postglacial rise in sea level. We present one hundred radiocarbon dates of Holocene transgressive deposits from the study area, ranging in age from ca. 10,000 to 5500 yr B.P. Relative sea level curves up to ca. 6000 yr B.P. were reconstructed for six locations. The curves have similar slopes prior to about 7000 yr B.P., indicating that sea level rise was much more rapid than any tectonic uplift at that time. The postglacial rise in sea level in New Zealand is considered, in general, to have culminated at about 6500 yr B.P. but the upper limit ages of transgressive deposits in our study area vary from ca. 5500 to 7000 yr B.P. At sites where the uplift rate is high the postglacial transgression culminated rather earlier than ca. 6500 yr B.P., and at sites where there is subsidence or there is very low uplift the culmination is later than ca. 6500 yr B.P. Nine of fourteen dates from fossil trees in growth position, that grew in and were buried by estuarine silt, cluster in the age range ca. 8000-8400 yr B.P. These data support the view that there was a minor regression or stillstand in the eustatic sea level rise at that time. Eleven tectonic subregions are recognized in the study area on the basis of average uplift rate. Most of these subregions coincide with those established from the number and ages of younger Holocene marine terraces of probable coseismic origin. ?? 1988.

The Distribution and Ages of Star Clusters in the Small Magellanic Cloud: Constraints on the Interaction History of the Magellanic Clouds

NASA Astrophysics Data System (ADS)

Bitsakis, Theodoros; González-Lópezlira, R. A.; Bonfini, P.; Bruzual, G.; Maravelias, G.; Zaritsky, D.; Charlot, S.; Ramírez-Siordia, V. H.

2018-02-01

We present a new study of the spatial distribution and ages of the star clusters in the Small Magellanic Cloud (SMC). To detect and estimate the ages of the star clusters we rely on the new fully automated method developed by Bitsakis et al. Our code detects 1319 star clusters in the central 18 deg2 of the SMC we surveyed (1108 of which have never been reported before). The age distribution of those clusters suggests enhanced cluster formation around 240 Myr ago. It also implies significant differences in the cluster distribution of the bar with respect to the rest of the galaxy, with the younger clusters being predominantly located in the bar. Having used the same setup, and data from the same surveys as for our previous study of the LMC, we are able to robustly compare the cluster properties between the two galaxies. Our results suggest that the bulk of the clusters in both galaxies were formed approximately 300 Myr ago, probably during a direct collision between the two galaxies. On the other hand, the locations of the young (≤50 Myr) clusters in both Magellanic Clouds, found where their bars join the H I arms, suggest that cluster formation in those regions is a result of internal dynamical processes. Finally, we discuss the potential causes of the apparent outside-in quenching of cluster formation that we observe in the SMC. Our findings are consistent with an evolutionary scheme where the interactions between the Magellanic Clouds constitute the major mechanism driving their overall evolution.

Analytical model of brittle destruction based on hypothesis of scale similarity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arakcheev, A. S., E-mail: asarakcheev@gmail.com; Lotov, K. V.

2012-08-15

The size distribution of dust particles in thermonuclear (fusion) devices is closely described by a power law, which may be related to the brittle destruction of materials. The hypothesis of scale similarity leads to the conclusion that the size distribution of particles formed as a result of a brittle destruction is described by a power law with the exponent -{alpha} that can range from -4 to -1. The model of brittle destruction is described in terms of the fractal geometry, and the distribution exponent is expressed via the fractal dimension of packing. Under additional assumptions, it is possible to refinemore » the {alpha} value and, vice versa, to determine the type of destruction using the measured size distribution of particles.« less

Effect of exercise on age-related changes in collagen fibril diameter distributions in the common digital extensor tendons of young horses.

PubMed

Edwards, Lindsey J; Goodship, Allen E; Birch, Helen L; Patterson-Kane, Janet C

2005-04-01

To determine whether specific treadmill exercise regimens would accelerate age-related changes in collagen fibril diameter distributions in the common digital extensor tendon (CDET) of the forelimbs of young Thoroughbreds. 24 female Thoroughbreds. Horses were trained for 18 weeks (6 horses; short term) or 18 months (5 horses; long term) on a high-speed treadmill; 2 age-matched control groups (6 horses/group) performed walking exercise only. Horses were (mean +/- SD) 24 +/- 1 months and 39 +/- 1 months old at termination of the short-term and long-term regimens, respectively. Midmetacarpal CDET specimens were obtained and processed for transmission electron microscopy. Diameter and area of at least 1,000 collagen fibrils/specimen were measured by use of computerized image analysis. Mass-average diameter (MAD) of collagen fibrils and collagen fibril index were calculated for each horse. Collagen fibril MAD for the older horses was significantly less than that for the younger horses. Exercise did not significantly affect fibril diameter or distributions in either age group, and collagen fibril index did not differ significantly between groups. Age-related reduction in collagen fibril MAD agreed with findings for other tendons and species. Training did not accelerate age-related change in the CDET in contrast to a reported decrease in collagen fibril MAD in the superficial digital flexor tendon of horses trained long term. Our results support the concept that the functionally distinct nature of the CDET and superficial digital flexor tendon in horses results in fundamentally different responses to high-speed exercise regimens.

Prosocial Behavior Increases with Age across Five Economic Games

PubMed Central

Matsumoto, Yoshie; Yamagishi, Toshio; Li, Yang; Kiyonari, Toko

2016-01-01

Ontogenic studies of human prosociality generally agree on that human prosociality increases from early childhood through early adulthood; however, it has not been established if prosociality increases beyond early adulthood. We examined a sample of 408 non-student residents from Tokyo, Japan, who were evenly distributed across age (20–59) and sex. Participants played five economic games each separated by a few months. We demonstrated that prosocial behavior increased with age beyond early adulthood and this effect was shown across all five economic games. A similar, but weaker, age-related trend was found in one of three social value orientation measures of prosocial preferences. We measured participants’ belief that manipulating others is a wise strategy for social success, and found that this belief declined with age. Participants’ satisfaction with the unilateral exploitation outcome of the prisoner’s dilemma games also declined with age. These two factors—satisfaction with the DC outcome in the prisoner’s dilemma games and belief in manipulation—mediated the age effect on both attitudinal and behavioral prosociality. Participants’ age-related socio-demographic traits such as marriage, having children, and owning a house weakly mediated the age effect on prosociality through their relationships with satisfaction with the DC outcome and belief in manipulation. PMID:27414803

Clustering and visualizing similarity networks of membrane proteins.

PubMed

Hu, Geng-Ming; Mai, Te-Lun; Chen, Chi-Ming

2015-08-01

We proposed a fast and unsupervised clustering method, minimum span clustering (MSC), for analyzing the sequence-structure-function relationship of biological networks, and demonstrated its validity in clustering the sequence/structure similarity networks (SSN) of 682 membrane protein (MP) chains. The MSC clustering of MPs based on their sequence information was found to be consistent with their tertiary structures and functions. For the largest seven clusters predicted by MSC, the consistency in chain function within the same cluster is found to be 100%. From analyzing the edge distribution of SSN for MPs, we found a characteristic threshold distance for the boundary between clusters, over which SSN of MPs could be properly clustered by an unsupervised sparsification of the network distance matrix. The clustering results of MPs from both MSC and the unsupervised sparsification methods are consistent with each other, and have high intracluster similarity and low intercluster similarity in sequence, structure, and function. Our study showed a strong sequence-structure-function relationship of MPs. We discussed evidence of convergent evolution of MPs and suggested applications in finding structural similarities and predicting biological functions of MP chains based on their sequence information. © 2015 Wiley Periodicals, Inc.

AIDS in adults 50 years of age and over: characteristics, trends and spatial distribution of the risk1

PubMed Central

Nogueira, Jordana de Almeida; Silva, Antônia Oliveira; de Sá, Laísa Ribeiro; de Almeida, Sandra Aparecida; Monroe, Aline Aparecida; Villa, Tereza Cristina Scatena

2014-01-01

Objective to analyze the sociodemographic characteristics, epidemic trend and spatial distribution of the risk of AIDS in adults 50 years of age and over. Method population-based, ecological study, that used secondary data from the Notifiable Disease Information System (Sinan/AIDS) of Paraíba state from the period January 2000 to December 2010. Results during the study period, 307 cases of AIDS were reported among people 50 years of age or over. There was a predominance of males (205/66, 8%), mixed race, and low education levels. The municipalities with populations above 100 thousand inhabitants reported 58.5% of the cases. There was a progressive increase in cases among women; an increasing trend in the incidence (positive linear correlation); and an advance in the geographical spread of the disease, with expansion to the coastal region and to the interior of the state, reaching municipalities with populations below 30 thousand inhabitants. In some locations the risk of disease was 100 times greater than the relative risk for the state. Conclusion aging, with the feminization and interiorization of the epidemic in adults 50 years of age and over, confirms the need for the induction of affirmative policies targeted toward this age group. PMID:25029044

Fuzzy Relational Databases: Representational Issues and Reduction Using Similarity Measures.

ERIC Educational Resources Information Center

Prade, Henri; Testemale, Claudette

1987-01-01

Compares and expands upon two approaches to dealing with fuzzy relational databases. The proposed similarity measure is based on a fuzzy Hausdorff distance and estimates the mismatch between two possibility distributions using a reduction process. The consequences of the reduction process on query evaluation are studied. (Author/EM)

Aging in Biometrics: An Experimental Analysis on On-Line Signature

PubMed Central

Galbally, Javier; Martinez-Diaz, Marcos; Fierrez, Julian

2013-01-01

The first consistent and reproducible evaluation of the effect of aging on dynamic signature is reported. Experiments are carried out on a database generated from two previous datasets which were acquired, under very similar conditions, in 6 sessions distributed in a 15-month time span. Three different systems, representing the current most popular approaches in signature recognition, are used in the experiments, proving the degradation suffered by this trait with the passing of time. Several template update strategies are also studied as possible measures to reduce the impact of aging on the system’s performance. Different results regarding the way in which signatures tend to change with time, and their most and least stable features, are also given. PMID:23894557

Age-specific bone tumour incidence rates are governed by stem cell exhaustion influencing the supply and demand of progenitor cells.

PubMed

Richardson, Richard B

2014-07-01

Knudson's carcinogenic model, which simulates incidence rates for retinoblastoma, provides compelling evidence for a two-stage mutational process. However, for more complex cancers, existing multistage models are less convincing. To fill this gap, I hypothesize that neoplasms preferentially arise when stem cell exhaustion creates a short supply of progenitor cells at ages of high proliferative demand. To test this hypothesis, published datasets were employed to model the age distribution of osteochondroma, a benign lesion, and osteosarcoma, a malignant one. The supply of chondrogenic stem-like cells in femur growth plates of children and adolescents was evaluated and compared with the progenitor cell demand of longitudinal bone growth. Similarly, the supply of osteoprogenitor cells from birth to old age was compared with the demands of bone formation. Results show that progenitor cell demand-to-supply ratios are a good risk indicator, exhibiting similar trends to the unimodal and bimodal age distributions of osteochondroma and osteosarcoma, respectively. The hypothesis also helps explain Peto's paradox and the finding that taller individuals are more prone to cancers and have shorter lifespans. The hypothesis was tested, in the manner of Knudson, by its ability to convincingly explain and demonstrate, for the first time, a bone tumour's bimodal age-incidence curve. Crown Copyright © 2014. Published by Elsevier Ireland Ltd. All rights reserved.

Similarity between Early and Middle Adolescent Close Friends' Beliefs about Personal Jurisdiction

ERIC Educational Resources Information Center

Daddis, Christopher

2008-01-01

Similarity in close friends' beliefs about personal jurisdiction was examined using questionnaires and interviews with 162 early (M[subscript age] = 11.82) and middle (M[subscript age] = 15.68) adolescents who were matched with reciprocally nominated close friends. Using the framework of social domain theory, beliefs about personal jurisdiction…

Theophylline kinetics in relation to age: the importance of smoking.

PubMed Central

Cusack, B; Kelly, J G; Lavan, J; Noel, J; O'Malley, K

1980-01-01

1 Single dose studies of theophylline kinetics were compared in groups of young and elderly smokers and non-smokers to assess the effect of age on theophylline absorption and the effect of smoking on drug metabolising enzyme activity in old age. 2 The rate and extent of absorption was not affected by age. Distribution and elimination kinetics were similar in young and elderly non-smokers. 3 In young subjects the elimination half-life of theophylline was shorter and clearance was significantly greater in smokers than in non-smokers. 4 In the elderly mean elimination half-life was significantly shorter in smokers and their plasma clearance was 40% higher than in non-smokers. The statistical difference for clearance was at the 7% level of significance. 5 These data indicate that ageing per se does not affect theophylline elimination and also that induction of theophylline metabolism due to smoking occurs in old age. Smoking is a variable that should be taken account of when assessing drug metabolism in elderly patients. PMID:7426272

Concurrent effects of age class and food distribution on immigration success and population dynamics in a small mammal.

PubMed

Rémy, Alice; Le Galliard, Jean-François; Odden, Morten; Andreassen, Harry P

2014-07-01

During the settlement stage of dispersal, the outcome of conflicts between residents and immigrants should depend on the social organization of resident populations as well as on individual traits of immigrants, such as their age class, body mass and/or behaviour. We have previously shown that spatial distribution of food influences the social organization of female bank voles (Myodes glareolus). Here, we aimed to determine the relative impact of food distribution and immigrant age class on the success and demographic consequences of female bank vole immigration. We manipulated the spatial distribution of food within populations having either clumped or dispersed food. After a pre-experimental period, we released either adult immigrants or juvenile immigrants, for which we scored sociability and aggressiveness prior to introduction. We found that immigrant females survived less well and moved more between populations than resident females, which suggest settlement costs. However, settled juvenile immigrants had a higher probability to reproduce than field-born juveniles. Food distribution had little effects on the settlement success of immigrant females. Survival and settlement probabilities of immigrants were influenced by adult female density in opposite ways for adult and juvenile immigrants, suggesting a strong adult-adult competition. Moreover, females of higher body mass at release had a lower probability to survive, and the breeding probability of settled immigrants increased with their aggressiveness and decreased with their sociability. Prior to the introduction of immigrants, resident females were more aggregated in the clumped food treatment than in the dispersed food treatment, but immigration reversed this relationship. In addition, differences in growth trajectories were seen during the breeding season, with populations reaching higher densities when adult immigrants were introduced in a plot with dispersed food, or when juvenile immigrants were

Kilauea summit overflows: Their ages and distribution in the Puna District, Hawai'i

USGS Publications Warehouse

Clague, D.A.; Hagstrum, J.T.; Beeson, M.H.; Champion, D.E.

1999-01-01

The tube-fed pahoehoe lava flows covering much of the northeast flank of Kilauea Volcano are named the 'Aila'au flows. Their eruption age, based on published and six new radiocarbon dates, is approximately AD 1445. The flows have distinctive paleomagnetic directions with steep inclinations (40??-50??) and easterly declinations (0??-10??E). The lava was transported ~40 km from the vent to the coast in long, large-diameter lava tubes; the longest tube (Kazumura Cave) reaches from near the summit to within several kilometers of the coast near Kaloli Point. The estimated volume of the 'Aila'au flow field is 5.2 ?? 0.8 km3, and the eruption that formed it probably lasted for approximately 50 years. Summit overflows from Kilauea may have been nearly continuous between approximately AD 1290 and 1470, during which time a series of shields formed at and around the summit. The 'Aila'au shield was either the youngest or the next to youngest in this series of shields. Site-mean paleomagnetic directions for lava flows underlying the 'Aila'au flows form only six groups. These older pahoehoe flows range in age from 2750 to 2200 years. Lava flows from most of these summit eruptions also reached the coast, but none appears as extensive as the 'Aila'au flow field. The chemistry of the melts erupted during each of these summit overflow events is remarkably similar, averaging approximately 6.3 wt.% MgO near the coast and 6.8 wt.% MgO near the summit. The present-day caldera probably formed more recently than the eruption that formed the 'Aila'au flows (estimated termination ca. AD 1470). The earliest explosive eruptions that formed the Keanakako'i Ash, which is stratigraphically above the 'Aila'au flows, cannot be older than this age.

Effects of Healthy Aging and Early-Stage Dementia of the Alzheimer’s Type on Components of Response Time Distributions in Three Attention Tasks

PubMed Central

Tse, Chi-Shing; Balota, David A.; Yap, Melvin J.; Duchek, Janet M.; McCabe, David P.

2009-01-01

Objective The characteristics of response time (RT) distributions beyond measures of central tendency were explored in three attention tasks across groups of young, healthy older adults and individuals with very mild dementia of the Alzheimer’s type (DAT). Method Participants were administered computerized Stroop, Simon, and Switching tasks, along with psychometric tasks that tap various cognitive abilities, and a standard personality inventory (NEO-FFI). Ex-Gaussian (and Vincentile) analyses were used to capture the characteristics of the RT distributions for each participant across the three tasks, which afforded three components: Mu, Sigma (mean and standard deviation of the modal portion of the distribution), and Tau (the positive tail of the distribution). Results The results indicated that across all three attention tasks, healthy aging produced large changes in the central tendency Mu parameter of the distribution along with some change in Sigma and Tau (mean ηp2=.17, .08, and .04, respectively). In contrast, early stage DAT primarily produced an increase in the Tau component (mean ηp2=.06). Tau was also correlated with the psychometric measures of episodic/semantic memory, working memory, and processing speed, and with the personality traits of Neuroticism and Conscientiousness. Structural equation modeling indicated a unique relation between a latent Tau construct (−.90), as opposed to Sigma (−.09) and Mu constructs (.24), with working memory measures. Conclusions The results suggest a critical role of attentional control systems in discriminating healthy aging from early stage DAT and the utility of reaction time distribution analyses to better specify the nature of such change. PMID:20438208

Observations and analysis of self-similar branching topology in glacier networks

USGS Publications Warehouse

Bahr, D.B.; Peckham, S.D.

1996-01-01

Glaciers, like rivers, have a branching structure which can be characterized by topological trees or networks. Probability distributions of various topological quantities in the networks are shown to satisfy the criterion for self-similarity, a symmetry structure which might be used to simplify future models of glacier dynamics. Two analytical methods of describing river networks, Shreve's random topology model and deterministic self-similar trees, are applied to the six glaciers of south central Alaska studied in this analysis. Self-similar trees capture the topological behavior observed for all of the glaciers, and most of the networks are also reasonably approximated by Shreve's theory. Copyright 1996 by the American Geophysical Union.

Cosmogenic Radionuclides in Antarctic Meteorites: Preliminary Results on Terrestrial Ages and Temporal Phenomena

NASA Astrophysics Data System (ADS)

Michlovich, E.; Vogt, S.; Wolf, S. F.; Elmore, D.; Lipschutz, M. E.

1993-07-01

the production rates for these radionuclides in this group of meteorites to be 18.2 +/- 2.3 and 58 +/- 13 dpm/kg respectively, consistent with production rates cited for falls [8]. Cosmic ray exposure ages using the ^10Be/^21Ne method outlined by Graf et al. [9] substantially agree with ages calculated from noble gases alone. Similar agreements are obtained between cosmic ray exposure ages based solely on noble gases and those calculated using ^26Al/^21Ne [9]. We calculated terrestrial ages using the secular equilibrium distribution for ^36Cl of 22.8 +/- 3.1 dpm/kg [10]. Our results are similar to those seen by Nishiizumi et al. [10], with a few ages ranging up to several hundred thousand years. It is worth noting that the Yamato meteorites measured in the present study, all of which happen to have been collected in the 1979 recovery effort ("Y79"), have a much older terrestrial age distribution (median age of 140 ka) than the Yamato distribution shown in [10]. We find it interesting that our Yamato age distribution is, however, consistent with the distribution of Y79 ages (median age, 110 ka) listed in [10], and that non-Y79 Yamato meteorites (median age in [10], 22 ka) seem to be responsible for a disproportionate number of the youngest Yamato meteorites. This possible collection area phenomenon is under investigation. Preliminary statistical analysis of the results using the preliminary terrestrial ages calculated here, trace-element data [3,4,11], and the methods elucidated in [2] is consistent with the notion that the meteorite flux sampled by the Earth has changed as a function of time. The latest results will be presented in Vail. References: [1] Koeberl C. and Cassidy W. A. (1991) GCA, 55, 3-18. [2] Lipschutz M. E. and Samuels S. M. (1991) GCA, 55, 19-34. [3] Wolf S. F. and Lipschutz M. E. (1992) LPS XXIII, 1545-1546. [4] Dodd R. T. et al. (1993) JGR, submitted. [5] Wetherill G. W. (1986) Nature, 319, 357-358. [6] Schultz L., personal communication. [7

Prevalence of vaginitis in different age groups among females in Greece.

PubMed

Sianou, Argiri; Galyfos, George; Moragianni, Dimitra; Baka, Stavroula

2017-08-01

Patients with vaginitis were classified into four groups: Group A (prepubertal under-aged females); Group B (pubertal under-aged females); Group C (reproductive age adult females); Group D (postmenopausal adult females). All vaginal specimens underwent microscopy, amine testing, Gram staining and culturing. Overall, 163 patients were included (33, 14, 81 and 35 patients, respectively). The most common infection was bacterial vaginosis (BV), followed by Ureaplasma infection, aerobic vaginitis (AV) and candidiasis. The most common AV-associated organism was Escherichia coli and the most common BV-associated organism was Gardnerella vaginalis. AV was more frequent in Group A, BV in Group C and Ureaplasma infections in Groups C/D. Decreased lactobacilli concentrations were associated with BV in fertile patients (Groups B-C). Although presentation of vaginitis is similar among females of different age in Greece, type and prevalence of pathogens differ. Normal vaginal flora changes are associated with higher risk of vaginitis in specific age groups. Impact Statement The worldwide incidence of reproductive tract infections has been increasing, with specific pathogens being associated with significant risk of morbidity and complications. However, literature data on the distribution of such infections in different age groups is limited. Therefore, the aim of this study was to provide data on the prevalence and causes of vaginitis in adult and non-adult females of all ages. This study has shown that although presentation of vaginitis is similar among females of different age groups and menstrual status in Greece, type and prevalence of responsible pathogens are different among groups. Changes in normal vaginal flora seem to be associated with higher risk of vaginitis in specific age-groups as well. These findings could contribute in adjusting diagnostic and therapeutic strategies for each age group according to the prevailing pathogens. Further research on antibiotic

Bayesian estimation of self-similarity exponent

NASA Astrophysics Data System (ADS)

Makarava, Natallia; Benmehdi, Sabah; Holschneider, Matthias

2011-08-01

In this study we propose a Bayesian approach to the estimation of the Hurst exponent in terms of linear mixed models. Even for unevenly sampled signals and signals with gaps, our method is applicable. We test our method by using artificial fractional Brownian motion of different length and compare it with the detrended fluctuation analysis technique. The estimation of the Hurst exponent of a Rosenblatt process is shown as an example of an H-self-similar process with non-Gaussian dimensional distribution. Additionally, we perform an analysis with real data, the Dow-Jones Industrial Average closing values, and analyze its temporal variation of the Hurst exponent.

Age structure and age-related performance of sulfur cinquefoil (Potentilla recta).

Treesearch

Dana L. Perkins; Catherine G. Parks; Kathleen A. Dwire; Bryan A. Endress; Kelsi L. Johnson

2006-01-01

Age distributions of sulfur cinquefoil populations were determined on sites that were historically grazed, cultivated, and mechanically disturbed. From 12 sites, a total of 279 reproductively active plants were collected and aged by using herbchronology (counting rings in the secondary root xylem of the root crown) to (1) estimate the age structure of the populations...

Pneumococcal responses are similar in Papua New Guinean children aged 3-5 years vaccinated in infancy with pneumococcal polysaccharide vaccine with or without prior pneumococcal conjugate vaccine, or without pneumococcal vaccination

PubMed Central

Richmond, Peter C.; Fuery, Angela; Anderson, Denise; Opa, Christine; Saleu, Gerard; Lai, Mildred; Francis, Jacinta P.; Alpers, Michael P.; Pomat, William S.; Lehmann, Deborah

2017-01-01

Trial design In an earlier trial, Papua New Guinean (PNG) children at high risk of pneumococcal disease were randomized to receive 0 or 3 doses of 7-valent pneumococcal conjugate vaccine (PCV7), followed by a single dose of 23-valent pneumococcal polysaccharide vaccine (PPV23) at 9 months of age. We here studied in a non-randomized follow-up trial the persistence of pneumococcal immunity in these children at 3–5 years of age (n = 132), and in 121 community controls of a similar age with no prior pneumococcal vaccination. Methods Circulating IgG antibody titers to all PCV7 and PPV23-only serotypes 2, 5 and 7F were measured before and after challenge with 1/5th of a normal PPV23 dose. Serotype-specific memory B-cells were enumerated at 10 months and 3–5 years of age for a subgroup of study children. Results Serotype-specific IgG antibody titers before and after challenge were similar for children who received PCV7/PPV23, PPV23 only, or no pneumococcal vaccines. Before challenge, at least 89% and 59% of children in all groups had serotype-specific titers ≥ 0.35μg/ml and ≥ 1.0 μg/ml, respectively. Post-challenge antibody titers were higher or similar to pre-challenge titers for most children independent of pneumococcal vaccination history. The rise in antibody titers was significantly lower when pre-challenge titers were higher. Overall the relative number of serotype-specific memory B-cells remained the same or increased between 10 months and 3–5 years of age, and there were no differences in serotype-specific memory B-cell numbers at 3–5 years of age between the three groups. Conclusions Immunity induced by PCV7 and/or PPV23 immunization in infancy does not exceed that of naturally acquired immunity in 3-5-year-old children living in a highly endemic area. Also, there was no evidence that PPV23 immunization in the first year of life following PCV7 priming induces longer-term hypo-responsiveness. Trial registration Clinicaltrials.gov NCT01414504 and NCT

Uterine cervix cancer treatment at Radiumhemmet: 90 years′ experience. Time trends of age, stage, and histopathology distribution

PubMed Central

Hellman, Kristina; Hellström, Ann-Cathrin; Pettersson, B Folke

2014-01-01

Since the introduction of screening programs for cervical cancer (CC) the incidence has decreased and CC is discovered at an earlier stage. The purpose of this study was to analyze time trends in age, stage, and histopathology over a 90-year period and to our knowledge this is the largest single institutional series in the literature of invasive cervical carcinoma (CC) cases. This is a retrospective study comprising 18,472 women treated for CC from 1914 until 2004 at Radiumhemmet, Stockholm. The material is part of the international CC statistics published since 1937 in the League of Nations' Annual Reports, and since 1958 under the patronage of International Federation of Gynecology and Obstetrics (FIGO). During the 90-year study period, the annual number of cases treated increased to over 400 up until 1965, after which there was a gradual drop to less than 100 cases in 2004. A pronounced shift toward earlier stages at diagnosis was noted. The mean age at diagnosis increased in all stages, predominantly in advanced stages. A reduction in squamous cell carcinoma (SCC) cases and a sixfold increase in the proportion of adenocarcinoma (AC) cases were observed. The mean age at diagnosis for squamous and AC cases shifted after 1970, when the SCC cases ultimately became 3 years older than the AC cases in contrast to around 1950 when they were 3 years younger than the AC cases. The changes in the distribution by age, stage, and histopathology during this 90-year period are probably associated with: improved social conditions and increased access to health care, the introduction of screening programs for CC in the 1960s, and a change in the risk factors for CC (changed sexual behavior, introduction of contraceptive pills, and changed smoking habits). This is a study on changes in the distribution by age, stage, and histopathology in a large series of cervical cancer treated in Sweden during a 90-year period. It also includes an historical review about the development of

Similar familial underpinnings for full and subsyndromal pediatric bipolar disorder: A familial risk analysis.

PubMed

Wozniak, Janet; Uchida, Mai; Faraone, Stephen V; Fitzgerald, Maura; Vaudreuil, Carrie; Carrellas, Nicholas; Davis, Jacqueline; Wolenski, Rebecca; Biederman, Joseph

2017-05-01

To examine the validity of subthreshold pediatric bipolar I disorder (BP-I), we compared the familial risk for BP-I in the child probands who had either full BP-I, subthreshold BP-I, ADHD, or were controls that neither had ADHD nor bipolar disorder. BP-I probands were youth aged 6-17 years meeting criteria for BP-I, full (N=239) or subthreshold (N=43), and also included were their first-degree relatives (N=687 and N=120, respectively). Comparators were youth with ADHD (N=162), controls without ADHD or bipolar disorder (N=136), and their first-degree relatives (N=511 and N=411, respectively). We randomly selected 162 non-bipolar ADHD probands and 136 non-bipolar, non-ADHD control probands of similar age and sex distribution to the BP-I probands from our case-control ADHD family studies. Psychiatric assessments were made by trained psychometricians using the Kiddie Schedule for Affective Disorders and Schizophrenia for School-Age Children Epidemiological Version (KSADS-E) and Structured Clinical Interview for DSM-IV (SCID) structured diagnostic interviews. We analyzed rates of bipolar disorder using multinomial logistic regression. Rates of full BP-I significantly differed between the four groups (χ 2 3 =32.72, P<.001): relatives of full BP-I probands and relatives of subthreshold BP-I probands had significantly higher rates of full BP-I than relatives of ADHD probands and relatives of control probands. Relatives of full BP-I, subthreshold BP-I, and ADHD probands also had significantly higher rates of major depressive disorder compared to relatives of control probands. Our results showed that youth with subthreshold BP-I had similarly elevated risk for BP-I and major depressive disorder in first-degree relatives as youth with full BP-I. These findings support the diagnostic continuity between subsyndromal and fully syndromatic states of pediatric BP-I disorder. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Age-related changes in pre- and post-conization HPV genotype distribution among women with high-grade cervical intraepithelial neoplasia.

PubMed

Giannella, Luca; Fodero, Cristina; Boselli, Fausto; Rubino, Teresa; Mfuta, Kabala; Prandi, Sonia

2017-04-01

To assess the effect of age on pre- and post-conization HPV genotype distribution. The present retrospective observational study included consecutive women with high-grade cervical intraepithelial neoplasia who underwent conization at the Cervical Cancer Screening Centre of Reggio Emilia, Italy, and University Hospital of Modena, Italy, between February 1, 2012, and October 31, 2014. Pre-conization and 6-month post-conization HPV genotyping results were compared between four age groups (<30, 30-39, 40-49, and ≥50 years) and age-related changes in the HPV genotypes present were evaluated. There were 162 patients included. The lowest occurrence of pre-conization high-risk and probable high-risk HPV genotypes was observed among patients aged at least 50 years when compared with younger patients (P=0.017). Conversely, women aged at least 50 years exhibited the highest level of post-conization high-risk and probable high-risk HPV genotypes (P=0.043). Additionally, an increasing incidence of recording identical pre- and post-conization HPV genotypes was associated with increasing age (P=0.024), as was increasing post-treatment recurrence of cervical intraepithelial neoplasia grade 2+ (P=0.030). The presence of high-risk and probable high-risk HPV genotypes was lowest among older patients before conization and was highest among these patients post-conization; post-treatment HPV clearance decreased with age and increasing age could be a risk factor for post-conization recurrence. © 2017 International Federation of Gynecology and Obstetrics.

Population ecology of the mallard: VII. Distribution and derivation of the harvest

USGS Publications Warehouse

Munro, Robert E.; Kimball, Charles F.

1982-01-01

This is the seventh in a series of comprehensive reports on population ecology of the mallard (Anas platyrhynchos) in North America. Banding records for 1961-1975 were used, together with information from previous reports in this series, to estimate annual and average preseason age and sex structure of the mallard population and patterns of harvest distribution and derivation. Age ratios in the pre-season population averaged 0.98 immatures per adult and ranged from 0.75 to 1.44. The adult male per female ration averaged 1.42. The young male per female ratio average 1.01. Geographic and annual differences in recovery distributions were associated with age, sex, and years after banding. Such variation might indicate that survival or band recovery rates, or both, change as a function of number of years after banding, and that estimates of these rates might thus be affected. Distribution of the mallard harvest from 16 major breeding ground reference areas to States, Provinces, and flyways is tabulated and illustrated. Seasonal (weekly) breeding ground derivation of the harvest within States and Provinces from the 16 reference areas also is tabulated. Harvest distributions, derivation, and similarity of derivation between harvest areas are summarily illustrated with maps. Derivation of harvest appears to be consistent throughout the hunting season in the middle and south central United States, encompassing States in both the Central and Mississippi flyways. However, weekly derivation patterns for most northern States suggest that early dates of hunting result in relatively greater harvest of locally derived mallard, in contrast to birds from more northern breeding areas.

Prosodic Similarity Effects in Short-Term Memory in Developmental Dyslexia.

PubMed

Goswami, Usha; Barnes, Lisa; Mead, Natasha; Power, Alan James; Leong, Victoria

2016-11-01

Children with developmental dyslexia are characterized by phonological difficulties across languages. Classically, this 'phonological deficit' in dyslexia has been investigated with tasks using single-syllable words. Recently, however, several studies have demonstrated difficulties in prosodic awareness in dyslexia. Potential prosodic effects in short-term memory have not yet been investigated. Here we create a new instrument based on three-syllable words that vary in stress patterns, to investigate whether prosodic similarity (the same prosodic pattern of stressed and unstressed syllables) exerts systematic effects on short-term memory. We study participants with dyslexia and age-matched and younger reading-level-matched typically developing controls. We find that all participants, including dyslexic participants, show prosodic similarity effects in short-term memory. All participants exhibited better retention of words that differed in prosodic structure, although participants with dyslexia recalled fewer words accurately overall compared to age-matched controls. Individual differences in prosodic memory were predicted by earlier vocabulary abilities, by earlier sensitivity to syllable stress and by earlier phonological awareness. To our knowledge, this is the first demonstration of prosodic similarity effects in short-term memory. The implications of a prosodic similarity effect for theories of lexical representation and of dyslexia are discussed. © 2016 The Authors. Dyslexia published by John Wiley & Sons Ltd. © 2016 The Authors. Dyslexia published by John Wiley & Sons Ltd.

Deconvolution analysis of 24-h serum cortisol profiles informs the amount and distribution of hydrocortisone replacement therapy.

PubMed

Peters, Catherine J; Hill, Nathan; Dattani, Mehul T; Charmandari, Evangelia; Matthews, David R; Hindmarsh, Peter C

2013-03-01

Hydrocortisone therapy is based on a dosing regimen derived from estimates of cortisol secretion, but little is known of how the dose should be distributed throughout the 24 h. We have used deconvolution analysis of 24-h serum cortisol profiles to determine 24-h cortisol secretion and distribution to inform hydrocortisone dosing schedules in young children and older adults. Twenty four hour serum cortisol profiles from 80 adults (41 men, aged 60-74 years) and 29 children (24 boys, aged 5-9 years) were subject to deconvolution analysis using an 80-min half-life to ascertain total cortisol secretion and distribution throughout the 24-h period. Mean daily cortisol secretion was similar between adults (6.3 mg/m(2) body surface area/day, range 5.1-9.3) and children (8.0 mg/m(2) body surface area/day, range 5.3-12.0). Peak serum cortisol concentration was higher in children compared with adults, whereas nadir serum cortisol concentrations were similar. Timing of the peak serum cortisol concentration was similar (07.05-07.25), whereas that of the nadir concentration occurred later in adults (midnight) compared with children (22.48) (P = 0.003). Children had the highest percentage of cortisol secretion between 06.00 and 12.00 (38.4%), whereas in adults this took place between midnight and 06.00 (45.2%). These observations suggest that the daily hydrocortisone replacement dose should be equivalent on average to 6.3 mg/m(2) body surface area/day in adults and 8.0 mg/m(2) body surface area/day in children. Differences in distribution of the total daily dose between older adults and young children need to be taken into account when using a three or four times per day dosing regimen. © 2012 Blackwell Publishing Ltd.

A new look at the Dynamic Similarity Hypothesis: the importance of swing phase.

PubMed

Raichlen, David A; Pontzer, Herman; Shapiro, Liza J

2013-01-01

The Dynamic Similarity Hypothesis (DSH) suggests that when animals of different size walk at similar Froude numbers (equal ratios of inertial and gravitational forces) they will use similar size-corrected gaits. This application of similarity theory to animal biomechanics has contributed to fundamental insights in the mechanics and evolution of a diverse set of locomotor systems. However, despite its popularity, many mammals fail to walk with dynamically similar stride lengths, a key element of gait that determines spontaneous speed and energy costs. Here, we show that the applicability of the DSH is dependent on the inertial forces examined. In general, the inertial forces are thought to be the centripetal force of the inverted pendulum model of stance phase, determined by the length of the limb. If instead we model inertial forces as the centripetal force of the limb acting as a suspended pendulum during swing phase (determined by limb center of mass position), the DSH for stride length variation is fully supported. Thus, the DSH shows that inter-specific differences in spatial kinematics are tied to the evolution of limb mass distribution patterns. Selection may act on morphology to produce a given stride length, or alternatively, stride length may be a "spandrel" of selection acting on limb mass distribution.

Effect of dopant distribution on aging of catalytic Cr-doped transition aluminas

NASA Astrophysics Data System (ADS)

Borisevich, Albina; Rashkeev, Sergey; Wang, Sanwu; Glazoff, Michael; Sohlberg, Karl; Pennycook, Stephen; Pantelides, Sokrates

2004-03-01

Metastable (transition) aluminas, in particular γ -Al_2O3 and η -Al_2O_3, are widely used as catalysts as well as supports for different transition metals. When doped with Cr, the two modifications exhibit remarkably different aging behavior: γ -Al_2O_3-supported catalysts degrade two orders of magnitude faster than those based on η -Al_2O_3. Here we use a combination of Z-contrast aberration-corrected scanning transmission electron microscopy (STEM), electron energy loss spectroscopy (EELS), and extended X-ray absorption fine structure (EXAFS) studies with first-principles calculations to determine the origin of this disparity. EXAFS data reveal that the coordination environments of Cr in the two forms are significantly different. STEM and EELS observations demonstrate that on γ -Al_2O3 Cr tends to segregate and form Cr_2O_3, while on η -Al_2O3 Cr is uniformly distributed. The reason for the dissimilarity, as shown by first-principles calculations, lies in the different reconstruction of the preferentially exposed 110 surface. In γ -Al_2O_3, it serves to destabilize the catalytically active Cr sites, at the same time inducing the formation of Cr_2O_3, while in η -Al_2O3 Cr atoms stay dispersed on the surface and catalytically active. This work provides interesting insights in the aging behavior of transition-metal based catalysts. Authors thank Dr. Saeed Alerasool (Engelhard Corp., Beechwood, OH) for providing samples and DOE (Grants DE-AC05-00OR22725 and DE-FC02-01CH11085) and NSF (Grant DMR-0111841) for financial support.

Young Children's Analogical Reasoning across Cultures: Similarities and Differences

ERIC Educational Resources Information Center

Richland, Lindsey Engle; Chan, Tsz-Kit; Morrison, Robert G.; Au, Terry Kit-Fong

2010-01-01

A cross-cultural comparison between U.S. and Hong Kong preschoolers examined factors responsible for young children's analogical reasoning errors. On a scene analogy task, both groups had adequate prerequisite knowledge of the key relations, were the same age, and showed similar baseline performance, yet Chinese children outperformed U.S. children…

Age distribution among NASA scientists and engineers

NASA Technical Reports Server (NTRS)

Ciancone, Michael L.

1989-01-01

The loss of technical expertise through attrition in NASA and the aerospace industry is discussed. This report documents historical age-related information for scientific and engineering personnel in general and the NASA Lewis Research Center in particular, for 1968 through 1987. Recommendations are made to promote discussion and to establish the groundwork for action.

Simulation study on the impact of air distribution on formaldehyde pollutant distribution in room

NASA Astrophysics Data System (ADS)

Wu, Jingtao; Wang, Jun; Cheng, Zhu

2017-01-01

In this paper, physical and mathematical model of a room was established based on the Airpak software. The velocity distribution, air age distribution, formaldehyde concentration distribution and Predicted Mean Vote(PMV), Predicted Percentage Dissatisfied(PPD) distribution in the ward of a hospital were simulated. In addition, the air volume was doubled, the change of indoor pollutant concentration distribution was simulated. And further, the change of air age was simulated. Through the simulation, it can help arrange the position of the air supply port, so it is very necessary to increase the comfort of the staff in the room. Finally, through the simulation of pollutant concentration distribution, it can be seen that when concentration of indoor pollutants was high, the supply air flow rate should be increased appropriately. Indoor pollutant will be discharged as soon as possible, which is very beneficial to human body health.

Isolation and Connectivity in Random Geometric Graphs with Self-similar Intensity Measures

NASA Astrophysics Data System (ADS)

Dettmann, Carl P.

2018-05-01

Random geometric graphs consist of randomly distributed nodes (points), with pairs of nodes within a given mutual distance linked. In the usual model the distribution of nodes is uniform on a square, and in the limit of infinitely many nodes and shrinking linking range, the number of isolated nodes is Poisson distributed, and the probability of no isolated nodes is equal to the probability the whole graph is connected. Here we examine these properties for several self-similar node distributions, including smooth and fractal, uniform and nonuniform, and finitely ramified or otherwise. We show that nonuniformity can break the Poisson distribution property, but it strengthens the link between isolation and connectivity. It also stretches out the connectivity transition. Finite ramification is another mechanism for lack of connectivity. The same considerations apply to fractal distributions as smooth, with some technical differences in evaluation of the integrals and analytical arguments.

The semantic-similarity effect in children: influence of long-term knowledge on verbal short-term memory.

PubMed

Monnier, Catherine; Bonthoux, Françoise

2011-11-01

The present research was designed to highlight the relation between children's categorical knowledge and their verbal short-term memory (STM) performance. To do this, we manipulated the categorical organization of the words composing lists to be memorized by 5- and 9-year-old children. Three types of word list were drawn up: semantically similar context-dependent (CD) lists, semantically similar context-independent (CI) lists, and semantically dissimilar lists. In line with the procedure used by Poirier and Saint-Aubin (1995), the dissimilar lists were produced using words from the semantically similar lists. Both 5- and 9-year-old children showed better recall for the semantically similar CD lists than they did for the unrelated lists. In the semantic similar CI condition, semantic similarity enhanced immediate serial recall only at age 9 but contributed to item information memory both at ages 5 and 9. These results, which indicate a semantic influence of long-term memory (LTM) on serial recall from age 5, are discussed in the light of current models of STM. Moreover, we suggest that differences between results at 5 and 9 years are compatible with pluralist models of development. ©2011 The British Psychological Society.

Ages of Records in Random Walks

NASA Astrophysics Data System (ADS)

Szabó, Réka; Vető, Bálint

2016-12-01

We consider random walks with continuous and symmetric step distributions. We prove universal asymptotics for the average proportion of the age of the kth longest lasting record for k=1,2,ldots and for the probability that the record of the kth longest age is broken at step n. Due to the relation to the Chinese restaurant process, the ranked sequence of proportions of ages converges to the Poisson-Dirichlet distribution.

Self-Concept of the Mentally Retarded Compared to Other Pupils of Similar Age.

ERIC Educational Resources Information Center

Richmond, Bert O.; And Others

Compared were the self concepts of 34 educable retarded children (mean age 11 years) with the self concepts of 34 fifth and sixth grade Blacks in an all Black school, 32 fifth and sixth grade Blacks in integrated classrooms, 31 sixth grade whites in an all white rural school, and 31 fifth grade whites in an all white suburban school. Results of…

An evaluation of sex-age-kill (SAK) model performance

USGS Publications Warehouse

Millspaugh, Joshua J.; Skalski, John R.; Townsend, Richard L.; Diefenbach, Duane R.; Boyce, Mark S.; Hansen, Lonnie P.; Kammermeyer, Kent

2009-01-01

The sex-age-kill (SAK) model is widely used to estimate abundance of harvested large mammals, including white-tailed deer (Odocoileus virginianus). Despite a long history of use, few formal evaluations of SAK performance exist. We investigated how violations of the stable age distribution and stationary population assumption, changes to male or female harvest, stochastic effects (i.e., random fluctuations in recruitment and survival), and sampling efforts influenced SAK estimation. When the simulated population had a stable age distribution and λ > 1, the SAK model underestimated abundance. Conversely, when λ < 1, the SAK overestimated abundance. When changes to male harvest were introduced, SAK estimates were opposite the true population trend. In contrast, SAK estimates were robust to changes in female harvest rates. Stochastic effects caused SAK estimates to fluctuate about their equilibrium abundance, but the effect dampened as the size of the surveyed population increased. When we considered both stochastic effects and sampling error at a deer management unit scale the resultant abundance estimates were within ±121.9% of the true population level 95% of the time. These combined results demonstrate extreme sensitivity to model violations and scale of analysis. Without changes to model formulation, the SAK model will be biased when λ ≠ 1. Furthermore, any factor that alters the male harvest rate, such as changes to regulations or changes in hunter attitudes, will bias population estimates. Sex-age-kill estimates may be precise at large spatial scales, such as the state level, but less so at the individual management unit level. Alternative models, such as statistical age-at-harvest models, which require similar data types, might allow for more robust, broad-scale demographic assessments.

On the probabilistic structure of water age

NASA Astrophysics Data System (ADS)

Porporato, Amilcare; Calabrese, Salvatore

2015-05-01

The age distribution of water in hydrologic systems has received renewed interest recently, especially in relation to watershed response to rainfall inputs. The purpose of this contribution is first to draw attention to existing theories of age distributions in population dynamics, fluid mechanics and stochastic groundwater, and in particular to the McKendrick-von Foerster equation and its generalizations and solutions. A second and more important goal is to clarify that, when hydrologic fluxes are modeled by means of time-varying stochastic processes, the age distributions must themselves be treated as random functions. Once their probabilistic structure is obtained, it can be used to characterize the variability of age distributions in real systems and thus help quantify the inherent uncertainty in the field determination of water age. We illustrate these concepts with reference to a stochastic storage model, which has been used as a minimalist model of soil moisture and streamflow dynamics.

Distribution of Candida albicans in the oral cavity of children aged 3-5 years of Uygur and Han nationality and their genotype in caries-active groups.

PubMed

Wu, N; Lin, J; Wu, L; Zhao, J

2015-01-30

We analyzed the distribution of Candida albicans in the oral cavity of 3-5-year-old children of Uygur and Han nationalities as well as their genotypes in caries-active groups in the Urumqi municipality. CHROMagar Candida was separately cultivated, and we identified 359 Uygur and Han children aged 3-5 years. We randomly selected 20 Han children and 20 Uygur children for this study. We chose a bacterial strain for polymerase chain reaction (PCR) 25S rDNA genotyping and random amplified polymorphic DNA (RAPD) genotyping. The rate of caries-active in Han children was higher than that in Uygur children, with values of 39.6 and 24.3%, respectively. The detection rate of C. albicans was closely correlated to the caries filling index classification (X(2) = 31.037, P = 0.000, r = 0.421; X(2) = 80.454, P = 0.000, r = 0.497). PCR of 25S rDNA from 40 strains of Han and Uygur children revealed 3 genotypes, while RAPD analysis revealed 5 genotypes. The distribution of 25S rDNA genotyping of Han children from PCR differed from that of Uygur children (X(2) = 7.697, P = 0.021), both of which were mainly the A type. RAPD genotyping of both Han and Uygur children showed similar results (X(2) = 1.573, P = 0.814). There were differences in the distributions of C. albicans in children of different nationalities. C. albicans is a key factor causing caries. The PCR 25S rDNA genotyping method is simple and sensitive, while the RAPD genotyping method is reliable and comprehensive.

A Review of Transformer Aging and Control Strategies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gourisetti, Sri Nikhil Gup; Kirkham, Harold; Sivaraman, Deepak

Transformer aging is an important challenge in power system. Distribution transformers themselves are minimally controllable, but smart meters provide excellent, new insights into electrical loads, which insights can be used to understand and mitigate transformer aging. The nature of transformer loads is changing with the integration of distributed energy resources (DERs) and electric vehicles (EVs). This paper first reviews factors that influence the aging of distribution transformers, including root causes of transformer failure. Existing and proposed load control methods are then discussed. A distribution model is introduced to help evaluate potential control methods.

Similarity in Middle School Mathematics: At the Crossroads of Geometry and Number

ERIC Educational Resources Information Center

Cox, Dana C.

2013-01-01

The mathematical idea of similarity is typically taught to students across the middle school years between ages 11 and 14. In this study, students' understanding of presimilarity is examined based on a set of clinical interviews of 21 students aged 12-13 years. Students were asked to scale a series of geometric figures and were found to use a…

Molecular techniques to distinguish morphologically similar Hydrilla verticillata, Egeria densa, Elodea nuttallii, and Elodea canadensis

USGS Publications Warehouse

Rybicki, Nancy B.; Kirshtein, Julie D.; Voytek, Mary A.

2013-01-01

The four submerged aquatic species, hydrilla (Hydrilla verticillata [monoecious and dioecious]), Brazilian waterweed (Egeria densa), Canadian waterweed (Elodea canadensis), and western waterweed (Elodea nuttallii), are difficult to positively identify because of their morphological similarity to each other, resulting in possible misidentification. This limits our ability to understand their past and present distribution, which is important in aquatic plant management. We investigated a molecular technique to identify these species, which are problematic because of their invasive nature on multiple continents. Approximately 100 samples of these species, ranging in age from 40-yr-old herbarium samples to recently collected plants, were collected from regions across the United States. The distribution and range of the samples collected in this research were compared to those reported in the literature. We confirmed information on the current wide distribution of both hydrilla biotypes in the United States and discovered that hydrilla had actually invaded the waterways near Washington, DC 6 yr earlier than originally reported. In addition, we found evidence of the confusion, dating back to the 1980s, between Canadian waterweed and western waterweed in the mid-Atlantic region of the United States. Canadian waterweed was previously reported as common and western waterweed as rare; however, our samples indicate the opposite is true. This information indicates there is a need for investigators to anticipate the spread of hydrilla populations to northern U.S. waterways, where it will compete with existing plant species, including Canadian and western waterweeds. Our ability to confirm distribution and pace of spread of invasive and noninvasive species will improve with increased application of molecular techniques.

Similar call signs

DOT National Transportation Integrated Search

2010-08-18

This presentation was given at the Partnership for Safety Meeting in Washington, DC. It examines the similarities that are found when calls signs are visually similar or similar sounding. Visually similar call signs increase the chances of controller...

The Spatio-temporal Distribution of Japanese Encephalitis Cases in Different Age Groups in Mainland China, 2004 – 2014

PubMed Central

Wang, Huanyu; Song, Miao; Li, Minghua; Fu, Shihong; Lv, Zhi; He, Ying; Lei, Wenwen; Wang, Bin; Lu, Xiaoqing; Liang, Guodong

2016-01-01

Background Japanese encephalitis (JE) is very prevalent in China, but the incidence of JE among children has been greatly reduced by extensive promotion of vaccinations. The incidence of JE among adults, however, has increased in some parts of China. Methods/Principal Findings Data on JE in mainland China, in terms of incidence, gender, and age, were collected between 2004 and 2014. We conducted spatial and temporal analyses on data from different age groups. Generally, children aged 0–15 years still represent the major population of JE cases in China, despite the gradual decrease in incidence over years. However, the incidence of JE among adults in several provinces is notably higher than the national average, especially during the epidemic waves in 2006, 2009, and 2013. The JE cases in the 0–15-year-old group are distributed mainly in the area south of the Yangtze River, with peak incidence occurring from July to September. In the adult group, especially for those over 40 years old, the JE cases are concentrated mainly in the area north of the Yangtze River. JE incidence in the adult group in September and October is significantly greater compared to the other groups. Further analysis using Local Indicators of Spatial Association (LISA) reveals that the distribution of adult JE cases in the six provinces north of the Yangtze River, between north 30–35° latitude and east 110–130° longitude, is a hotspot for adult JE cases. Conclusions/Significance The rate of JE case increase for adults is much greater than for children and has become a public health issue. Therefore, studies on the necessity and feasibility of vaccinating adults who live in JE-endemic areas, but have never been vaccinated for JE, should become a new focus of JE prevention in the future. PMID:27050414

A Similarity Theory for Unsaturated Downdrafts within Clouds.

NASA Astrophysics Data System (ADS)

Emanuel, Kerry A.

1981-08-01

Recent observations of cumulus clouds strongly support the hypothesis of Squires (1958) that much of the mixing within such clouds is associated with downward propagating currents initiated near their tops. A similarity theory is here proposed to describe the properties of such currents; the use of similarity is defended on the basis of the observed and predicted scale of the downdrafts. The theory suggests that downward-propagating unsaturated thermals are pervasive throughout all but the largest convective clouds and that quasi-steady unsaturated downdraft plumes may exist in the lower portions of cumulonimbi. In addition to providing a reasonable explanation for the microstructure of and liquid water distribution within cumulus clouds, the theory appears to account for certain severe convective phenomena, including down-bursts. A new but related cloud instability is proposed to account for the occurrence of mamma.

Maize varieties released in different eras have similar root length density distributions in the soil, which are negatively correlated with local concentrations of soil mineral nitrogen.

PubMed

Ning, Peng; Li, Sa; White, Philip J; Li, Chunjian

2015-01-01

Larger, and deeper, root systems of new maize varieties, compared to older varieties, are thought to have enabled improved acquisition of soil resources and, consequently, greater grain yields. To compare the spatial distributions of the root systems of new and old maize varieties and their relationships with spatial variations in soil concentrations of available nitrogen (N), phosphorus (P) and potassium (K), two years of field experiments were performed using six Chinese maize varieties released in different eras. Vertical distributions of roots, and available N, P and K in the 0-60 cm soil profile were determined in excavated soil monoliths at silking and maturity. The results demonstrated that new maize varieties had larger root dry weight, higher grain yield and greater nutrient accumulation than older varieties. All varieties had similar total root length and vertical root distribution at silking, but newer varieties maintained greater total root length and had more roots in the 30-60 cm soil layers at maturity. The spatial variation of soil mineral N (Nmin) in each soil horizon was larger than that of Olsen-P and ammonium-acetate-extractable K, and was inversely correlated with root length density (RLD), especially in the 0-20 cm soil layer. It was concluded that greater acquisition of mineral nutrients and higher yields of newer varieties were associated with greater total root length at maturity. The negative relationship between RLD and soil Nmin at harvest for all varieties suggests the importance of the spatial distribution of the root system for N uptake by maize.

Maize Varieties Released in Different Eras Have Similar Root Length Density Distributions in the Soil, Which Are Negatively Correlated with Local Concentrations of Soil Mineral Nitrogen

PubMed Central

Ning, Peng; Li, Sa; White, Philip J.; Li, Chunjian

2015-01-01

Larger, and deeper, root systems of new maize varieties, compared to older varieties, are thought to have enabled improved acquisition of soil resources and, consequently, greater grain yields. To compare the spatial distributions of the root systems of new and old maize varieties and their relationships with spatial variations in soil concentrations of available nitrogen (N), phosphorus (P) and potassium (K), two years of field experiments were performed using six Chinese maize varieties released in different eras. Vertical distributions of roots, and available N, P and K in the 0–60 cm soil profile were determined in excavated soil monoliths at silking and maturity. The results demonstrated that new maize varieties had larger root dry weight, higher grain yield and greater nutrient accumulation than older varieties. All varieties had similar total root length and vertical root distribution at silking, but newer varieties maintained greater total root length and had more roots in the 30–60 cm soil layers at maturity. The spatial variation of soil mineral N (Nmin) in each soil horizon was larger than that of Olsen-P and ammonium-acetate-extractable K, and was inversely correlated with root length density (RLD), especially in the 0–20 cm soil layer. It was concluded that greater acquisition of mineral nutrients and higher yields of newer varieties were associated with greater total root length at maturity. The negative relationship between RLD and soil Nmin at harvest for all varieties suggests the importance of the spatial distribution of the root system for N uptake by maize. PMID:25799291

Effect of the physiognomy of Attalea butyracea (Arecoideae) on population density and age distribution of Rhodnius prolixus (Triatominae).

PubMed

Urbano, Plutarco; Poveda, Cristina; Molina, Jorge

2015-04-01

Rhodnius prolixus Stål, 1859 is one of the main vectors of Trypanosoma (Schyzotrypanum) cruzi Chagas, 1909. In its natural forest environment, this triatomine is mainly found in palm tree crowns, where it easily establishes and develops dense populations. The aim of this study was to evaluate the effect of the physiognomy and reproductive status of Attalea butyracea on the population relative density and age structure of R. prolixus and to determine the vector's population stratification according to the vertical and horizontal profile of an A. butyracea forest. Using live bait traps, 150 individuals of A. butyracea with different physiognomy and 40 individuals with similar physiognomy (crown size, number of leaves, palm tree height, diameter at breast height, reproductive status) were sampled for triatomines in Yopal, Casanare-Colombia. Temperature and relative humidity were measured in the crown of the palm tree. Entomological indices and natural infection rates were also determined. The relative population density of R. prolixus on natural A. butyracea groves is associated with the palm's height, number of leaves and crown volume. The young immature stages were present mostly at the crown's base and the advanced immature stages and adults were present mostly at the crown of the palm tree. This distribution correlates with the temperature stability and relative humidity in the base and the fluctuation of both environmental variables in the palm's crown. A higher density of R. prolixus was found as the palm tree height increased and as the distance of the palm with respect to the forest border decreased, especially towards anthropically intervened areas. A density index of 12.6 individuals per palm tree with an infestation index of 88.9% and a colonization index of 98.7% was observed. 85.2% was the infection index with T. cruzi. The physiognomy of palm trees affects the relative population density and the distribution of developmental stages of R. prolixus

Evaluating gyrochronology on the zero-age-main-sequence: rotation periods in the southern open cluster Blanco 1 from the Kelt-South survey

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cargile, P. A.; Pepper, J.; Siverd, R.

2014-02-10

We report periods for 33 members of Blanco 1 as measured from Kilodegree Extremely Little Telescope-South light curves, the first reported rotation periods for this benchmark zero-age-main-sequence open cluster. The distribution of these stars spans from late-A or early-F dwarfs to mid-K with periods ranging from less than a day to ∼8 days. The rotation period distribution has a morphology similar to the coeval Pleiades cluster, suggesting the universal nature of stellar rotation distributions. Employing two different gyrochronology methods, we find an age of 146{sub −14}{sup +13} Myr for the cluster. Using the same techniques, we infer an age ofmore » 134{sub −10}{sup +9} Myr for the Pleiades measured from existing literature rotation periods. These rotation-derived ages agree with independently determined cluster ages based on the lithium depletion boundary technique. Additionally, we evaluate different gyrochronology models and quantify levels of agreement between the models and the Blanco 1/Pleiades rotation period distributions, including incorporating the rotation distributions of clusters at ages up to 1.1 Gyr. We find the Skumanich-like spin-down rate sufficiently describes the rotation evolution of stars hotter than the Sun; however, we find cooler stars rotating faster than predicted by a Skumanich law, suggesting a mass dependence in the efficiency of stellar angular momentum loss rate. Finally, we compare the Blanco 1 and Pleiades rotation period distributions to available nonlinear angular momentum evolution models. We find they require a significant mass dependence on the initial rotation rate of solar-type stars to reproduce the observed range of rotation periods at a given stellar mass and are furthermore unable to predict the observed over-density of stars along the upper envelope of the clusters' rotation distributions.« less

The smell of age: perception and discrimination of body odors of different ages.

PubMed

Mitro, Susanna; Gordon, Amy R; Olsson, Mats J; Lundström, Johan N

2012-01-01

Our natural body odor goes through several stages of age-dependent changes in chemical composition as we grow older. Similar changes have been reported for several animal species and are thought to facilitate age discrimination of an individual based on body odors, alone. We sought to determine whether humans are able to discriminate between body odor of humans of different ages. Body odors were sampled from three distinct age groups: Young (20-30 years old), Middle-age (45-55), and Old-age (75-95) individuals. Perceptual ratings and age discrimination performance were assessed in 41 young participants. There were significant differences in ratings of both intensity and pleasantness, where body odors from the Old-age group were rated as less intense and less unpleasant than body odors originating from Young and Middle-age donors. Participants were able to discriminate between age categories, with body odor from Old-age donors mediating the effect also after removing variance explained by intensity differences. Similarly, participants were able to correctly assign age labels to body odors originating from Old-age donors but not to body odors originating from other age groups. This experiment suggests that, akin to other animals, humans are able to discriminate age based on body odor alone and that this effect is mediated mainly by body odors emitted by individuals of old age.

The Smell of Age: Perception and Discrimination of Body Odors of Different Ages

PubMed Central

Mitro, Susanna; Gordon, Amy R.; Olsson, Mats J.; Lundström, Johan N.

2012-01-01

Our natural body odor goes through several stages of age-dependent changes in chemical composition as we grow older. Similar changes have been reported for several animal species and are thought to facilitate age discrimination of an individual based on body odors, alone. We sought to determine whether humans are able to discriminate between body odor of humans of different ages. Body odors were sampled from three distinct age groups: Young (20–30 years old), Middle-age (45–55), and Old-age (75–95) individuals. Perceptual ratings and age discrimination performance were assessed in 41 young participants. There were significant differences in ratings of both intensity and pleasantness, where body odors from the Old-age group were rated as less intense and less unpleasant than body odors originating from Young and Middle-age donors. Participants were able to discriminate between age categories, with body odor from Old-age donors mediating the effect also after removing variance explained by intensity differences. Similarly, participants were able to correctly assign age labels to body odors originating from Old-age donors but not to body odors originating from other age groups. This experiment suggests that, akin to other animals, humans are able to discriminate age based on body odor alone and that this effect is mediated mainly by body odors emitted by individuals of old age. PMID:22666457

Sequence Similarity Presenter: a tool for the graphic display of similarities of long sequences for use in presentations.

PubMed

Fröhlich, K U

1994-04-01

A new method for the presentation of alignments of long sequences is described. The degree of identity for the aligned sequences is averaged for sections of a fixed number of residues. The resulting values are converted to shades of gray, with white corresponding to lack of identity and black corresponding to perfect identity. A sequence alignment is represented as a bar filled with varying shades of gray. The display is compact and allows for a fast and intuitive recognition of the distribution of regions with a high similarity. It is well suited for the presentation of alignments of long sequences, e.g. of protein superfamilies, in plenary lectures. The method is implemented as a HyperCard stack for Apple Macintosh computers. Several options for the modification of the output are available (e.g. background reduction, size of the summation window, consideration of amino acid similarity, inclusion of graphic markers to indicate specific domains). The output is a PostScript file which can be printed, imported as EPS or processed further with Adobe Illustrator.

Similar Familial Underpinnings for Full and Subsyndromal Pediatric Bipolar Disorder: A Familial Risk Analysis

PubMed Central

Wozniak, Janet; Uchida, Mai; Faraone, Stephen V.; Fitzgerald, Maura; Vaudreuil, Carrie; Carrellas, Nicholas; Davis, Jacqueline; Wolenski, Rebecca; Biederman, Joseph

2017-01-01

Objectives To examine the validity of subthreshold pediatric bipolar-I (BP-I) disorder, we compared the familial risk for BP-I disorder in child probands with full BP-I disorder, subthreshold BP-I disorder, ADHD, and non-ADHD/non-bipolar disorder controls. Methods Probands were youth ages 6–17 meeting criteria for BP-I disorder, full (N=239) or subthreshold (N=43), and their first degree relatives (N=687 and N=120, respectively). Comparators were youth with ADHD (N=162), controls (N=136), and their first-degree relatives (N=511 and N=411, respectively). We randomly selected 162 non-bipolar ADHD probands and 136 non-bipolar non-ADHD control probands of similar age and sex distribution to the BP-I probands from our case-control ADHD family studies. Psychiatric assessments were made by trained psychometricians using the KSADS-E and SCID structured diagnostic interviews. We analyzed rates of bipolar disorder using multinomial logistic regression. Results Rates of full bipolar-I disorder significantly differed between the four groups (χ23 = 32.72, p<0.001): relatives of full BP-I and relatives of subthreshold BP-I probands had significantly higher rates of full BP-I disorder than relatives of ADHD probands and relatives of control probands. Relatives of full BP-I, subthreshold BP-I, and ADHD probands also had significantly higher rates of major depressive disorder (MDD) compared to relatives of control probands. Conclusions Our results showed that youth with subthreshold BP-I disorder had similarly elevated risk for BP-I disorder and MDD in first-degree relatives as youth with full BP-I disorder. These findings support the diagnostic continuity between subsyndromal and fully syndromatic states of pediatric BP-I disorder. PMID:28544732

Effect of Number and Similarity on Children's Plural Comprehension

ERIC Educational Resources Information Center

Lanter, Jennifer A.; Basche, Richard A.

2014-01-01

During the first years of language development, toddlers coordinate multiple cues in order to acquire the plural form. The aim of this study was to manipulate object similarity as well as set size in order to determine whether these variables impact children's comprehension of plurality. One-hundred-and-fifty children ranging in age from 22 to 36…

THE AGES OF HIGH-MASS X-RAY BINARIES IN NGC 2403 AND NGC 300

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, Benjamin F.; Binder, Breanna A.; Dalcanton, Julianne J.

2013-07-20

We have examined resolved stellar photometry from HST imaging surrounding 18 high-mass X-ray binary (HMXB) candidates in NGC 300 and NGC 2403 as determined from combined Chandra/HST analysis. We have fit the color-magnitude distribution of the surrounding stars with stellar evolution models. All but one region in NGC 300 and two in NGC 2403 contain a population with an age between 20 and 70 Myr. One of the candidates is the ultraluminous X-ray source in NGC 2403, which we associate with a 60 {+-} 5 Myr old population. These age distributions provide additional evidence that 16 of these 18 candidatesmore » are HMXBs. Furthermore, our results suggest that the most common HMXB age in these galaxies is 40-55 Myr. This preferred age is similar to observations of HMXBs in the Small Magellanic Cloud, providing new evidence of this formation timescale, but in higher metallicity populations. We suggest that this preferred HMXB age is the result of the fortuitous combination of two physical effects. First, this is the age of a population when the greatest rate of core-collapse events should be occurring, maximizing neutron star production. Second, this is the age when B stars are most likely to be actively losing mass. We also discuss our results in the context of HMXB feedback in galaxies, confirming HMXBs as a potentially important source of energy for the interstellar medium in low-mass galaxies.« less

Long‐term trends in fall age ratios of black brant

USGS Publications Warehouse

Ward, David H.; Amundson, Courtney L.; Stehn, Robert A.; Dau, Christian P.

2018-01-01

Accurate estimates of the age composition of populations can inform past reproductive success and future population trajectories. We examined fall age ratios (juveniles:total birds) of black brant (Branta bernicla nigricans; brant) staging at Izembek National Wildlife Refuge near the tip of the Alaska Peninsula, southwest Alaska, USA, 1963 to 2015. We also investigated variation in fall age ratios associated with sampling location, an index of flock size, survey effort, day of season, observer, survey platform (boat‐ or land‐based) and tide stage. We analyzed data using logistic regression models implemented in a Bayesian framework. Mean predicted fall age ratio controlling for survey effort, day of year, and temporal and spatial variation was 0.24 (95% CL = 0.23, 0.25). Overall trend in age ratios was −0.6% per year (95% CL = −1.3%, 0.2%), resulting in an approximate 26% decline in the proportion of juveniles over the study period. We found evidence for variation across a range of variables implying that juveniles are not randomly distributed in space and time within Izembek Lagoon. Age ratios varied by location within the study area and were highly variable among years. They decreased with the number of birds aged (an index of flock size) and increased throughout September before leveling off in early October and declining in late October. Age ratios were similar among tide stages and observers and were lower during boat‐based (offshore) than land‐based (nearshore) surveys. Our results indicate surveys should be conducted annually during early to mid‐October to ensure the entire population is present and available for sampling, and throughout Izembek Lagoon to account for spatiotemporal variation in age ratios. Sampling should include a wide range of flock sizes representative of their distribution and occur in flocks located near and off shore. Further research evaluating the cause of declining age ratios in the fall population is necessary

BMI-for-age in South Asian children of 0-20 years in the Netherlands: secular changes and misclassification by WHO growth references.

PubMed

de Wilde, J A; Dekker, M; Middelkoop, B J C

2018-03-01

South Asians are prone to cardiometabolic disease at lower BMI levels than most other ethnic groups, starting in childhood. The magnitude of BMI misclassifications is unknown. To compare the BMI distribution of contemporary South Asian 0-20 year olds in the Netherlands with: (1) The South Asian norm reference (secular trends); and (2) The WHO child growth standard and reference. The BMI-for-age distribution of 6677 routine measurements of 3322 South Asian children, aged 0-20 years, was described with the LMS method and BMI z-scores. The BMI distribution in South Asian 0-4 year olds was almost similar to the norm reference (mean BMI z-score = 0.11, skewness = 0.31, SD = 1.0), whereas in 5-19 year olds the distribution had shifted upwards (mean = 0.53) and widened (skewness = -0.12, SD = 1.08). Overweight (incl. obesity) and obesity peaked at 8-10 years, at 45-48% and 35-37%, respectively. Relative to the WHO references, the BMI distribution was left-shifted at ages 0-4 years (mean BMI z-score = -0.46, skewness = 0.23, SD = 0.98) and widened at ages 5-20 years (mean = 0.05; skewness = -0.02, SD = 1.40). At most ages, thinness rates were significantly higher and obesity rates lower than based on South Asian norms. A secular change of BMI-for-age in South Asian children mostly affected children >4 years. WHO references likely under-estimate overweight and obesity rates in South Asian children.

Evidence of Long Range Dependence and Self-similarity in Urban Traffic Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thakur, Gautam S; Helmy, Ahmed; Hui, Pan

2015-01-01

Transportation simulation technologies should accurately model traffic demand, distribution, and assignment parame- ters for urban environment simulation. These three param- eters significantly impact transportation engineering bench- mark process, are also critical in realizing realistic traffic modeling situations. In this paper, we model and charac- terize traffic density distribution of thousands of locations around the world. The traffic densities are generated from millions of images collected over several years and processed using computer vision techniques. The resulting traffic den- sity distribution time series are then analyzed. It is found using the goodness-of-fit test that the traffic density dis- tributions follows heavy-tailmore » models such as Log-gamma, Log-logistic, and Weibull in over 90% of analyzed locations. Moreover, a heavy-tail gives rise to long-range dependence and self-similarity, which we studied by estimating the Hurst exponent (H). Our analysis based on seven different Hurst estimators strongly indicate that the traffic distribution pat- terns are stochastically self-similar (0.5 H 1.0). We believe this is an important finding that will influence the design and development of the next generation traffic simu- lation techniques and also aid in accurately modeling traffic engineering of urban systems. In addition, it shall provide a much needed input for the development of smart cities.« less

Distribution of molar mass and branching index of natural rubber from Hevea brasiliensis trees of different age by size exclusion chromatography coupled with online viscometry.

PubMed

Phan, T N; Lan, N T; Nga, N T

2004-05-01

Natural rubber from hevea brasiliensis trees (Thailand, RRIM 600 clone) of different age (8, 20, and 35 years) were characterized by size exclusion chromatography coupled with online viscometry according to their distribution of molar mass and branching index at a temperature of 70 degrees C using cyclohexane as solvent. Washing with an aqueous solution of sodium dodecylsulfate and subsequent saponification purified the natural rubber samples. With this procedure physical branching points caused by phospholipids, proteins and hydrophobic terminal units, mainly fatty acids, of the natural rubber (cis-1,4-polyisoprene) molecule, could be removed leading to completely soluble polymer samples. All samples investigated possess a very broad (10 to 50,000 kg/mol) and distinct bimodal molar mass distribution. With increasing age the peak area in the low molar mass region decreases favoring the peak area in the high molar mass region. By plotting the branching index as a function of the both, the molar mass and the age of the trees.

The increase of the functional entropy of the human brain with age.

PubMed

Yao, Y; Lu, W L; Xu, B; Li, C B; Lin, C P; Waxman, D; Feng, J F

2013-10-09

We use entropy to characterize intrinsic ageing properties of the human brain. Analysis of fMRI data from a large dataset of individuals, using resting state BOLD signals, demonstrated that a functional entropy associated with brain activity increases with age. During an average lifespan, the entropy, which was calculated from a population of individuals, increased by approximately 0.1 bits, due to correlations in BOLD activity becoming more widely distributed. We attribute this to the number of excitatory neurons and the excitatory conductance decreasing with age. Incorporating these properties into a computational model leads to quantitatively similar results to the fMRI data. Our dataset involved males and females and we found significant differences between them. The entropy of males at birth was lower than that of females. However, the entropies of the two sexes increase at different rates, and intersect at approximately 50 years; after this age, males have a larger entropy.

The Increase of the Functional Entropy of the Human Brain with Age

PubMed Central

Yao, Y.; Lu, W. L.; Xu, B.; Li, C. B.; Lin, C. P.; Waxman, D.; Feng, J. F.

2013-01-01

We use entropy to characterize intrinsic ageing properties of the human brain. Analysis of fMRI data from a large dataset of individuals, using resting state BOLD signals, demonstrated that a functional entropy associated with brain activity increases with age. During an average lifespan, the entropy, which was calculated from a population of individuals, increased by approximately 0.1 bits, due to correlations in BOLD activity becoming more widely distributed. We attribute this to the number of excitatory neurons and the excitatory conductance decreasing with age. Incorporating these properties into a computational model leads to quantitatively similar results to the fMRI data. Our dataset involved males and females and we found significant differences between them. The entropy of males at birth was lower than that of females. However, the entropies of the two sexes increase at different rates, and intersect at approximately 50 years; after this age, males have a larger entropy. PMID:24103922

A new methodological approach to adjust alcohol exposure distributions to improve the estimation of alcohol-attributable fractions.

PubMed

Parish, William J; Aldridge, Arnie; Allaire, Benjamin; Ekwueme, Donatus U; Poehler, Diana; Guy, Gery P; Thomas, Cheryll C; Trogdon, Justin G

2017-11-01

To assess the burden of excessive alcohol use, researchers estimate alcohol-attributable fractions (AAFs) routinely. However, under-reporting in survey data can bias these estimates. We present an approach that adjusts for under-reporting in the estimation of AAFs, particularly within subgroups. This framework is a refinement of a previous method conducted by Rehm et al. We use a measurement error model to derive the 'true' alcohol distribution from a 'reported' alcohol distribution. The 'true' distribution leverages per-capita sales data to identify the distribution average and then identifies the shape of the distribution with self-reported survey data. Data are from the National Alcohol Survey (NAS), the National Household Survey on Drug Abuse (NHSDA) and the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC). We compared our approach with previous approaches by estimating the AAF of female breast cancer cases. Compared with Rehm et al.'s approach, our refinement performs similarly under a gamma assumption. For example, among females aged 18-25 years, the two approaches produce estimates from NHSDA that are within a percentage point. However, relaxing the gamma assumption generally produces more conservative evidence. For example, among females aged 18-25 years, estimates from NHSDA based on the best-fitting distribution are only 19.33% of breast cancer cases, which is a much smaller proportion than the gamma-based estimates of approximately 28%. A refinement of Rehm et al.'s approach to adjusting for underreporting in the estimation of alcohol-attributable fractions provides more flexibility. This flexibility can avoid biases associated with failing to account for the underlying differences in alcohol consumption patterns across different study populations. Comparisons of our refinement with Rehm et al.'s approach show that results are similar when a gamma distribution is assumed. However, results are appreciably lower when the best

Understanding phengite argon closure using single grain fusion age distributions in the Cycladic Blueschist Unit on Syros, Greece

NASA Astrophysics Data System (ADS)

Uunk, Bertram; Brouwer, Fraukje; ter Voorde, Marlies; Wijbrans, Jan

2018-02-01

The preservation of 40Ar/39Ar ages of high pressure (HP) metamorphic white mica reflects an interplay of processes that mobilise 40Ar, either through mica recrystallisation or by diffusive 40Ar loss. The applicability of resulting ages for dating tectonic processes is critically dependent on whether either of these processes can be proven to be efficient and exclusively active in removing 40Ar from mica. If not, preservation of an inherited or mixed age signal in a sample must be considered for interpretation. The Cycladic Blueschist Unit on Syros has become a new focal area in the discussion of the geological significance of argon age results from multi-grain step heating experiments. While some argue that age results can directly be linked to deformation or metamorphic growth events, others interpret age results to reflect the interplay of protracted recrystallisation and partial resetting, preserving a mixed age signal. Here, we demonstrate the potential of a new approach of multiple single grain fusion dating. Using the distribution of ages at the sample, section and regional scale, we show that in Northern Syros mica ages display systematic trends that can be understood as the result of three competing processes: 1) crystallisation along the prograde to peak metamorphic path, 2) a southward trend of increasing 40Ar loss by diffusion and 3) localised and rock type dependent deformation or metamorphic reactions leading to an observed age spread typically limited to ∼10 Myr at the section scale. None of the sections yielded the anomalously old age results that would be diagnostic for significant excess 40Ar. The recorded trends in ages for each of the studied sections reflect a range of P-T conditions and duration of metamorphism. Diffusion modelling shows that in a typical subduction metamorphic loop, subtle variations in P-T-t history can explain that age contrasts occur on a regional scale but are limited on the outcrop scale. Our new approach provides a

Cognitive Process Development as Measured by an Adapted Version of Wechsler's Similarities Test

ERIC Educational Resources Information Center

Rozencwajg, Paulette

2007-01-01

This paper studies the development of taxonomic processing as measured by an adapted version of the Wechsler Similarities subtest, which distinguishes between categorization of concrete and abstract words. Two factors--age and concreteness--are also tested by a recall task. The results show an age-related increase in taxonomic categorization,…

Spatial embedding of structural similarity in the cerebral cortex

PubMed Central

Song, H. Francis; Kennedy, Henry; Wang, Xiao-Jing

2014-01-01

Recent anatomical tracing studies have yielded substantial amounts of data on the areal connectivity underlying distributed processing in cortex, yet the fundamental principles that govern the large-scale organization of cortex remain unknown. Here we show that functional similarity between areas as defined by the pattern of shared inputs or outputs is a key to understanding the areal network of cortex. In particular, we report a systematic relation in the monkey, human, and mouse cortex between the occurrence of connections from one area to another and their similarity distance. This characteristic relation is rooted in the wiring distance dependence of connections in the brain. We introduce a weighted, spatially embedded random network model that robustly gives rise to this structure, as well as many other spatial and topological properties observed in cortex. These include features that were not accounted for in any previous model, such as the wide range of interareal connection weights. Connections in the model emerge from an underlying distribution of spatially embedded axons, thereby integrating the two scales of cortical connectivity—individual axons and interareal pathways—into a common geometric framework. These results provide insights into the origin of large-scale connectivity in cortex and have important implications for theories of cortical organization. PMID:25368200

Colorectal anatomy in adults at computed tomography colonography: normal distribution and the effect of age, sex, and body mass index.