Sample records for joint demographic history

  1. Joint Inference of Population Assignment and Demographic History

    PubMed Central

    Choi, Sang Chul; Hey, Jody

    2011-01-01

    A new approach to assigning individuals to populations using genetic data is described. Most existing methods work by maximizing Hardy–Weinberg and linkage equilibrium within populations, neither of which will apply for many demographic histories. By including a demographic model, within a likelihood framework based on coalescent theory, we can jointly study demographic history and population assignment. Genealogies and population assignments are sampled from a posterior distribution using a general isolation-with-migration model for multiple populations. A measure of partition distance between assignments facilitates not only the summary of a posterior sample of assignments, but also the estimation of the posterior density for the demographic history. It is shown that joint estimates of assignment and demographic history are possible, including estimation of population phylogeny for samples from three populations. The new method is compared to results of a widely used assignment method, using simulated and published empirical data sets. PMID:21775468

  2. Geographical barriers and climate influence demographic history in narrowleaf cottonwoods.

    PubMed

    Evans, L M; Allan, G J; DiFazio, S P; Slavov, G T; Wilder, J A; Floate, K D; Rood, S B; Whitham, T G

    2015-04-01

    Studies of genetic variation can clarify the role of geography and spatio-temporal variation of climate in shaping demography, particularly in temperate zone tree species with large latitudinal ranges. Here, we examined genetic variation in narrowleaf cottonwood, Populus angustifolia, a dominant riparian tree. Using multi-locus surveys of polymorphism in 363 individuals across the species' 1800?km latitudinal range, we found that, first, P. angustifolia has stronger neutral genetic structure than many forest trees (simple sequence repeat (SSR) FST=0.21), with major genetic groups corresponding to large apparent geographical barriers to gene flow. Second, using SSRs and putatively neutral sequenced loci, coalescent simulations indicated that populations diverged before the last glacial maximum (LGM), suggesting the presence of population structure before the LGM. Third, the LGM and subsequent warming appear to have had different influences on each of these distinct populations, with effective population size reduction in the southern extent of the range but major expansion in the north. These results are consistent with the hypothesis that climate and geographic barriers have jointly affected the demographic history of P. angustifolia, and point the importance of both factors as being instrumental in shaping genetic variation and structure in widespread forest trees. PMID:25585921

  3. Genome-scale analysis of demographic history and adaptive selection.

    PubMed

    Wu, Qi; Zheng, Pingping; Hu, Yibu; Wei, Fuwen

    2014-02-01

    One of the main topics in population genetics is identification of adaptive selection among populations. For this purpose, population history should be correctly inferred to evaluate the effect of random drift and exclude it in selection identification. With the rapid progress in genomics in the past decade, vast genome-scale variations are available for population genetic analysis, which however requires more sophisticated models to infer species' demographic history and robust methods to detect local adaptation. Here we aim to review what have been achieved in the fields of demographic modeling and selection detection. We summarize their rationales, implementations, and some classical applications. We also propose that some widely-used methods can be improved in both theoretical and practical aspects in near future. PMID:24474201

  4. Cattle demographic history modelled from autosomal sequence variation

    PubMed Central

    Murray, Caitriona; Huerta-Sanchez, Emilia; Casey, Fergal; Bradley, Daniel G.

    2010-01-01

    The phylogeography of cattle genetic variants has been extensively described and has informed the history of domestication. However, there remains a dearth of demographic models inferred from such data. Here, we describe sequence diversity at 37 000 bp sampled from 17 genes in cattle from Africa, Europe and India. Clearly distinct population histories are suggested between Bos indicus and Bos taurus, with the former displaying higher diversity statistics. We compare the unfolded site frequency spectra in each to those simulated using a diffusion approximation method and build a best-fitting model of past demography. This implies an earlier, possibly glaciation-induced population bottleneck in B. taurus ancestry with a later, possibly domestication-associated demographic constriction in B. indicus. Strikingly, the modelled indicine history also requires a majority secondary admixture from the South Asian aurochs, indicating a complex, more diffuse domestication process. This perhaps involved multiple domestications and/or introgression from wild oxen to domestic herds; the latter is plausible from archaeological evidence of contemporaneous wild and domestic remains across different regions of South Asia. PMID:20643743

  5. Demographic history and gene flow during silkworm domestication

    PubMed Central

    2014-01-01

    Background Gene flow plays an important role in domestication history of domesticated species. However, little is known about the demographic history of domesticated silkworm involving gene flow with its wild relative. Results In this study, four model-based evolutionary scenarios to describe the demographic history of B. mori were hypothesized. Using Approximate Bayesian Computation method and DNA sequence data from 29 nuclear loci, we found that the gene flow at bottleneck model is the most likely scenario for silkworm domestication. The starting time of silkworm domestication was estimated to be approximate 7,500 years ago; the time of domestication termination was 3,984 years ago. Using coalescent simulation analysis, we also found that bi-directional gene flow occurred during silkworm domestication. Conclusions Estimates of silkworm domestication time are nearly consistent with the archeological evidence and our previous results. Importantly, we found that the bi-directional gene flow might occur during silkworm domestication. Our findings add a dimension to highlight the important role of gene flow in domestication of crops and animals. PMID:25123546

  6. Genealogy and Demographic History of a Widespread Amphibian throughout Indochina.

    PubMed

    Blair, Christopher; Davy, Christina M; Ngo, Andre; Orlov, Nikolai L; Shi, Hai-tao; Lu, Shun-qing; Gao, Lan; Rao, Ding-qi; Murphy, Robert W

    2013-01-01

    Relatively little is known about spatial patterns of cryptic diversity in tropical species and the processes that generate them. Few studies examine the geographic distribution of genetic lineages in Southeast Asia, an area hypothesized to harbor substantial cryptic diversity. We investigated the evolutionary history of Asian tree frogs of the Polypedates leucomystax complex (n = 172) based on 1800 bp of the mtDNA genes ND1 and cytochrome b and tested hypotheses pertaining to climate, geology, and dispersal patterns. Analyses revealed substantial genetic diversity and lineage divergence throughout the region with evidence for widespread sympatric lineages and a general north versus south clustering. Relaxed molecular clock analysis and tests for demographic expansion identified an initial cladogenesis during the Miocene with subsequent Plio-Pleistocene diversification, with the former corresponding to periods of increased aridity and the onset of monsoonal weather systems. Rates of diversification were relatively constant until the Early Pleistocene when rates increased exponentially. We found equivocal evidence for isolation-by-distance and a potential role of some landscape features as partial barriers to dispersal. Finally, our analyses showed that divergence between insular and mainland populations occurred before Homo sapiens colonized Southeast Asia, suggesting that historical human-mediated dispersal did not drive insular diversification. Our results suggested that demographic expansion in the Late Pleistocene resulted in widespread sympatric lineages in the P. leucomystax complex throughout southern China and Indochina and further clarified the evolutionary history of lineages within P. leucomystax. PMID:23125408

  7. Demographic history and linkage disequilibrium in human populations.

    PubMed

    Laan, M; Pääbo, S

    1997-12-01

    In the human genome, linkage disequilibrium (LD)--the non-random association of alleles at chromosomal loci--has been studied mainly in regions surrounding disease genes on affected chromosomes. Consequently, little information is available on the distribution of LD across anonymous genomic regions in the general population. However, demographic history is expected to influence the extent of overall LD across the genome, so a population that has been of constant size will display higher levels of LD than a population that has expanded. In support of this, the extent of LD between anonymous loci on chromosome 4 in chimpanzees (as a model of a population of constant size) has been compared to that in Finns (as a model of an expanded population; refs 8,9) and found to exhibit more LD than in the latter population. In Europe, studies of mitochondrial (mt) DNA sequences have suggested that most populations have experienced expansion, whereas the Saami in northern Fenno-Scandinavia have been of constant size (Table 1). Thus, in northern Europe, populations with radically different demographic histories live in close geographic proximity to each other. We studied the allelic associations between anonymous microsatellite loci on the X chromosome in the Saami and neighbouring populations and found dramatically higher levels of LD in the Saami than in other populations in the region. This indicates that whereas recently expanded populations, such as the Finns, are well suited to map single disease genes affected by recent mutations, populations that have been of constant size, such as the Saami, may be much better suited to map genes for complex traits that are caused by older mutations. PMID:9398845

  8. Comparative Genetic Structure and Demographic History in Endemic Galápagos Weevils

    PubMed Central

    Stepien, Courtney C.; Sijapati, Manisha; Roque Albelo, Lázaro

    2012-01-01

    The challenge of maintaining genetic diversity within populations can be exacerbated for island endemics if they display population dynamics and behavioral attributes that expose them to genetic drift without the benefits of gene flow. We assess patterns of the genetic structure and demographic history in 27 populations of 9 species of flightless endemic Galápagos weevils from 9 of the islands and 1 winged introduced close relative. Analysis of mitochondrial DNA reveals a significant population structure and moderately variable, though demographically stable, populations for lowland endemics (FST = 0.094–0.541; ?: 0.014–0.042; Mismatch P = 0.003–0.026; and D(Tajima) = ?0.601 to 1.203), in contrast to signals of past contractions and expansions in highland specialists on 2 islands (Mismatch P = 0.003–0.026 and D(Tajima) = ?0.601 to 1.203). We interpret this series of variable and highly structured population groups as a system of long-established, independently founded island units, where structuring could be a signal of microallopatric differentiation due to patchy host plant distribution and poor dispersal abilities. We suggest that the severe reduction and subsequent increase of a suitably moist habitat that accompanied past climatic variation could have contributed to the observed population fluctuations in highland specialists. We propose the future exploration of hybridization between the introduced and highland endemic species on Santa Cruz, especially given the expansion of the introduced species into the highlands, the sensitivity to past climatic variation detected in highland populations, and the potentially threatened state of single-island endemics. PMID:22174444

  9. Genetic diversification and demographic history of the cactophilic pseudoscorpion Dinocheirus arizonensis from the Sonoran Desert

    E-print Network

    Markow, Therese

    Genetic diversification and demographic history of the cactophilic pseudoscorpion Dinocheirus and infer demographic history of the cacto- philic chernetid pseudoscorpion, Dinocheirus arizonensis (Banks to genetic isolation and diversification in clades I and II of D. arizonensis are discussed. Ă? 2008 Elsevier

  10. Demographic history and rare allele sharing among human populations.

    PubMed

    Gravel, Simon; Henn, Brenna M; Gutenkunst, Ryan N; Indap, Amit R; Marth, Gabor T; Clark, Andrew G; Yu, Fuli; Gibbs, Richard A; Bustamante, Carlos D

    2011-07-19

    High-throughput sequencing technology enables population-level surveys of human genomic variation. Here, we examine the joint allele frequency distributions across continental human populations and present an approach for combining complementary aspects of whole-genome, low-coverage data and targeted high-coverage data. We apply this approach to data generated by the pilot phase of the Thousand Genomes Project, including whole-genome 2-4× coverage data for 179 samples from HapMap European, Asian, and African panels as well as high-coverage target sequencing of the exons of 800 genes from 697 individuals in seven populations. We use the site frequency spectra obtained from these data to infer demographic parameters for an Out-of-Africa model for populations of African, European, and Asian descent and to predict, by a jackknife-based approach, the amount of genetic diversity that will be discovered as sample sizes are increased. We predict that the number of discovered nonsynonymous coding variants will reach 100,000 in each population after ?1,000 sequenced chromosomes per population, whereas ?2,500 chromosomes will be needed for the same number of synonymous variants. Beyond this point, the number of segregating sites in the European and Asian panel populations is expected to overcome that of the African panel because of faster recent population growth. Overall, we find that the majority of human genomic variable sites are rare and exhibit little sharing among diverged populations. Our results emphasize that replication of disease association for specific rare genetic variants across diverged populations must overcome both reduced statistical power because of rarity and higher population divergence. PMID:21730125

  11. Demographic history and rare allele sharing among human populations

    PubMed Central

    Gravel, Simon; Henn, Brenna M.; Gutenkunst, Ryan N.; Indap, Amit R.; Marth, Gabor T.; Clark, Andrew G.; Yu, Fuli; Gibbs, Richard A.; Bustamante, Carlos D.; Altshuler, David L.; Durbin, Richard M.; Abecasis, Gonçalo R.; Bentley, David R.; Chakravarti, Aravinda; Clark, Andrew G.; Collins, Francis S.; De La Vega, Francisco M.; Donnelly, Peter; Egholm, Michael; Flicek, Paul; Gabriel, Stacey B.; Gibbs, Richard A.; Knoppers, Bartha M.; Lander, Eric S.; Lehrach, Hans; Mardis, Elaine R.; McVean, Gil A.; Nickerson, Debbie A.; Peltonen, Leena; Schafer, Alan J.; Sherry, Stephen T.; Wang, Jun; Wilson, Richard K.; Gibbs, Richard A.; Deiros, David; Metzker, Mike; Muzny, Donna; Reid, Jeff; Wheeler, David; Wang, Jun; Li, Jingxiang; Jian, Min; Li, Guoqing; Li, Ruiqiang; Liang, Huiqing; Tian, Geng; Wang, Bo; Wang, Jian; Wang, Wei; Yang, Huanming; Zhang, Xiuqing; Zheng, Huisong; Lander, Eric S.; Altshuler, David L.; Ambrogio, Lauren; Bloom, Toby; Cibulskis, Kristian; Fennell, Tim J.; Gabriel, Stacey B.; Jaffe, David B.; Shefler, Erica; Sougnez, Carrie L.; Bentley, David R.; Gormley, Niall; Humphray, Sean; Kingsbury, Zoya; Koko-Gonzales, Paula; Stone, Jennifer; McKernan, Kevin J.; Costa, Gina L.; Ichikawa, Jeffry K.; Lee, Clarence C.; Sudbrak, Ralf; Lehrach, Hans; Borodina, Tatiana A.; Dahl, Andreas; Davydov, Alexey N.; Marquardt, Peter; Mertes, Florian; Nietfeld, Wilfiried; Rosenstiel, Philip; Schreiber, Stefan; Soldatov, Aleksey V.; Timmermann, Bernd; Tolzmann, Marius; Egholm, Michael; Affourtit, Jason; Ashworth, Dana; Attiya, Said; Bachorski, Melissa; Buglione, Eli; Burke, Adam; Caprio, Amanda; Celone, Christopher; Clark, Shauna; Conners, David; Desany, Brian; Gu, Lisa; Guccione, Lorri; Kao, Kalvin; Kebbel, Andrew; Knowlton, Jennifer; Labrecque, Matthew; McDade, Louise; Mealmaker, Craig; Minderman, Melissa; Nawrocki, Anne; Niazi, Faheem; Pareja, Kristen; Ramenani, Ravi; Riches, David; Song, Wanmin; Turcotte, Cynthia; Wang, Shally; Mardis, Elaine R.; Wilson, Richard K.; Dooling, David; Fulton, Lucinda; Fulton, Robert; Weinstock, George; Durbin, Richard M.; Burton, John; Carter, David M.; Churcher, Carol; Coffey, Alison; Cox, Anthony; Palotie, Aarno; Quail, Michael; Skelly, Tom; Stalker, James; Swerdlow, Harold P.; Turner, Daniel; De Witte, Anniek; Giles, Shane; Gibbs, Richard A.; Wheeler, David; Bainbridge, Matthew; Challis, Danny; Sabo, Aniko; Yu, Fuli; Yu, Jin; Wang, Jun; Fang, Xiaodong; Guo, Xiaosen; Li, Ruiqiang; Li, Yingrui; Luo, Ruibang; Tai, Shuaishuai; Wu, Honglong; Zheng, Hancheng; Zheng, Xiaole; Zhou, Yan; Li, Guoqing; Wang, Jian; Yang, Huanming; Marth, Gabor T.; Garrison, Erik P.; Huang, Weichun; Indap, Amit; Kural, Deniz; Lee, Wan-Ping; Leong, Wen Fung; Quinlan, Aaron R.; Stewart, Chip; Stromberg, Michael P.; Ward, Alistair N.; Wu, Jiantao; Lee, Charles; Mills, Ryan E.; Shi, Xinghua; Daly, Mark J.; DePristo, Mark A.; Altshuler, David L.; Ball, Aaron D.; Banks, Eric; Bloom, Toby; Browning, Brian L.; Cibulskis, Kristian; Fennell, Tim J.; Garimella, Kiran V.; Grossman, Sharon R.; Handsaker, Robert E.; Hanna, Matt; Hartl, Chris; Jaffe, David B.; Kernytsky, Andrew M.; Korn, Joshua M.; Li, Heng; Maguire, Jared R.; McCarroll, Steven A.; McKenna, Aaron; Nemesh, James C.; Philippakis, Anthony A.; Poplin, Ryan E.; Price, Alkes; Rivas, Manuel A.; Sabeti, Pardis C.; Schaffner, Stephen F.; Shefler, Erica; Shlyakhter, Ilya A.; Cooper, David N.; Ball, Edward V.; Mort, Matthew; Phillips, Andrew D.; Stenson, Peter D.; Sebat, Jonathan; Makarov, Vladimir; Ye, Kenny; Yoon, Seungtai C.; Bustamante, Carlos D.; Clark, Andrew G.; Boyko, Adam; Degenhardt, Jeremiah; Gravel, Simon; Gutenkunst, Ryan N.; Kaganovich, Mark; Keinan, Alon; Lacroute, Phil; Ma, Xin; Reynolds, Andy; Clarke, Laura; Flicek, Paul; Cunningham, Fiona; Herrero, Javier; Keenen, Stephen; Kulesha, Eugene; Leinonen, Rasko; McLaren, William M.; Radhakrishnan, Rajesh; Smith, Richard E.; Zalunin, Vadim; Zheng-Bradley, Xiangqun; Korbel, Jan O.; Stütz, Adrian M.; Humphray, Sean; Bauer, Markus; Cheetham, R. Keira; Cox, Tony; Eberle, Michael; James, Terena; Kahn, Scott; Murray, Lisa; Chakravarti, Aravinda; Ye, Kai; De La Vega, Francisco M.; Fu, Yutao; Hyland, Fiona C. L.; Manning, Jonathan M.; McLaughlin, Stephen F.; Peckham, Heather E.; Sakarya, Onur; Sun, Yongming A.; Tsung, Eric F.; Batzer, Mark A.; Konkel, Miriam K.; Walker, Jerilyn A.; Sudbrak, Ralf; Albrecht, Marcus W.; Amstislavskiy, Vyacheslav S.; Herwig, Ralf; Parkhomchuk, Dimitri V.; Sherry, Stephen T.; Agarwala, Richa; Khouri, Hoda M.; Morgulis, Aleksandr O.; Paschall, Justin E.; Phan, Lon D.; Rotmistrovsky, Kirill E.; Sanders, Robert D.

    2011-01-01

    High-throughput sequencing technology enables population-level surveys of human genomic variation. Here, we examine the joint allele frequency distributions across continental human populations and present an approach for combining complementary aspects of whole-genome, low-coverage data and targeted high-coverage data. We apply this approach to data generated by the pilot phase of the Thousand Genomes Project, including whole-genome 2–4× coverage data for 179 samples from HapMap European, Asian, and African panels as well as high-coverage target sequencing of the exons of 800 genes from 697 individuals in seven populations. We use the site frequency spectra obtained from these data to infer demographic parameters for an Out-of-Africa model for populations of African, European, and Asian descent and to predict, by a jackknife-based approach, the amount of genetic diversity that will be discovered as sample sizes are increased. We predict that the number of discovered nonsynonymous coding variants will reach 100,000 in each population after ?1,000 sequenced chromosomes per population, whereas ?2,500 chromosomes will be needed for the same number of synonymous variants. Beyond this point, the number of segregating sites in the European and Asian panel populations is expected to overcome that of the African panel because of faster recent population growth. Overall, we find that the majority of human genomic variable sites are rare and exhibit little sharing among diverged populations. Our results emphasize that replication of disease association for specific rare genetic variants across diverged populations must overcome both reduced statistical power because of rarity and higher population divergence. PMID:21730125

  12. 2 Demographics of an Aging America 7JOINT CENTER FOR HOUSING STUDIES OF HARVARD UNIVERSITY

    E-print Network

    Liu, X. Shirley

    by immigration in recent decades, America's population is becoming increasingly diverse. But racial and ethnic2 Demographics of an Aging America 7JOINT CENTER FOR HOUSING STUDIES OF HARVARD UNIVERSITY minority population will likely spur an increase in multigenerational households. #12;HOUSING AMERICA

  13. Impact of Sampling Schemes on Demographic Inference: An Empirical Study in Two Species with Different Mating Systems and Demographic Histories

    PubMed Central

    St. Onge, K. R.; Palmé, A. E.; Wright, S. I.; Lascoux, M.

    2012-01-01

    Most species have at least some level of genetic structure. Recent simulation studies have shown that it is important to consider population structure when sampling individuals to infer past population history. The relevance of the results of these computer simulations for empirical studies, however, remains unclear. In the present study, we use DNA sequence datasets collected from two closely related species with very different histories, the selfing species Capsella rubella and its outcrossing relative C. grandiflora, to assess the impact of different sampling strategies on summary statistics and the inference of historical demography. Sampling strategy did not strongly influence the mean values of Tajima’s D in either species, but it had some impact on the variance. The general conclusions about demographic history were comparable across sampling schemes even when resampled data were analyzed with approximate Bayesian computation (ABC). We used simulations to explore the effects of sampling scheme under different demographic models. We conclude that when sequences from modest numbers of loci (<60) are analyzed, the sampling strategy is generally of limited importance. The same is true under intermediate or high levels of gene flow (4Nm > 2–10) in models in which global expansion is combined with either local expansion or hierarchical population structure. Although we observe a less severe effect of sampling than predicted under some earlier simulation models, our results should not be seen as an encouragement to neglect this issue. In general, a good coverage of the natural range, both within and between populations, will be needed to obtain a reliable reconstruction of a species’s demographic history, and in fact, the effect of sampling scheme on polymorphism patterns may itself provide important information about demographic history. PMID:22870403

  14. Inferring demographic history from a spectrum of shared haplotype lengths.

    PubMed

    Harris, Kelley; Nielsen, Rasmus

    2013-06-01

    There has been much recent excitement about the use of genetics to elucidate ancestral history and demography. Whole genome data from humans and other species are revealing complex stories of divergence and admixture that were left undiscovered by previous smaller data sets. A central challenge is to estimate the timing of past admixture and divergence events, for example the time at which Neanderthals exchanged genetic material with humans and the time at which modern humans left Africa. Here, we present a method for using sequence data to jointly estimate the timing and magnitude of past admixture events, along with population divergence times and changes in effective population size. We infer demography from a collection of pairwise sequence alignments by summarizing their length distribution of tracts of identity by state (IBS) and maximizing an analytic composite likelihood derived from a Markovian coalescent approximation. Recent gene flow between populations leaves behind long tracts of identity by descent (IBD), and these tracts give our method power by influencing the distribution of shared IBS tracts. In simulated data, we accurately infer the timing and strength of admixture events, population size changes, and divergence times over a variety of ancient and recent time scales. Using the same technique, we analyze deeply sequenced trio parents from the 1000 Genomes project. The data show evidence of extensive gene flow between Africa and Europe after the time of divergence as well as substructure and gene flow among ancestral hominids. In particular, we infer that recent African-European gene flow and ancient ghost admixture into Europe are both necessary to explain the spectrum of IBS sharing in the trios, rejecting simpler models that contain less population structure. PMID:23754952

  15. Inferring Demographic History from a Spectrum of Shared Haplotype Lengths

    PubMed Central

    Harris, Kelley; Nielsen, Rasmus

    2013-01-01

    There has been much recent excitement about the use of genetics to elucidate ancestral history and demography. Whole genome data from humans and other species are revealing complex stories of divergence and admixture that were left undiscovered by previous smaller data sets. A central challenge is to estimate the timing of past admixture and divergence events, for example the time at which Neanderthals exchanged genetic material with humans and the time at which modern humans left Africa. Here, we present a method for using sequence data to jointly estimate the timing and magnitude of past admixture events, along with population divergence times and changes in effective population size. We infer demography from a collection of pairwise sequence alignments by summarizing their length distribution of tracts of identity by state (IBS) and maximizing an analytic composite likelihood derived from a Markovian coalescent approximation. Recent gene flow between populations leaves behind long tracts of identity by descent (IBD), and these tracts give our method power by influencing the distribution of shared IBS tracts. In simulated data, we accurately infer the timing and strength of admixture events, population size changes, and divergence times over a variety of ancient and recent time scales. Using the same technique, we analyze deeply sequenced trio parents from the 1000 Genomes project. The data show evidence of extensive gene flow between Africa and Europe after the time of divergence as well as substructure and gene flow among ancestral hominids. In particular, we infer that recent African-European gene flow and ancient ghost admixture into Europe are both necessary to explain the spectrum of IBS sharing in the trios, rejecting simpler models that contain less population structure. PMID:23754952

  16. Multilocus patterns of nucleotide variability and the demographic and selection history of Drosophila melanogaster populations

    Microsoft Academic Search

    Penelope R. Haddrill; Kevin R. Thornton; Brian Charlesworth; Peter Andolfatto

    2007-01-01

    Uncertainty about the demographic history of populations can hamper genome-wide scans for selection based on population genetic models. To obtain a portrait of the effects of demographic history on genome variability patterns in Drosophila melanogaster populations, we surveyed noncoding DNA polymorphism at 10 X-linked loci in large samples from three African and two non-African populations. All five populations show significant

  17. Demographic analysis of continuous-time life-history models

    PubMed Central

    De Roos, André M

    2008-01-01

    I present a computational approach to calculate the population growth rate, its sensitivity to life-history parameters and associated statistics like the stable population distribution and the reproductive value for exponentially growing populations, in which individual life history is described as a continuous development through time. The method is generally applicable to analyse population growth and performance for a wide range of individual life-history models, including cases in which the population consists of different types of individuals or in which the environment is fluctuating periodically. It complements comparable methods developed for discrete-time dynamics modelled with matrix or integral projection models. The basic idea behind the method is to use Lotka's integral equation for the population growth rate and compute the integral occurring in that equation by integrating an ordinary differential equation, analogous to recently derived methods to compute steady-states of physiologically structured population models. I illustrate application of the method using a number of published life-history models. PMID:18047588

  18. Joint Genome Institute's Automation Approach and History

    SciTech Connect

    Roberts, Simon

    2006-07-05

    Department of Energy/Joint Genome Institute (DOE/JGI) collaborates with DOE national laboratories and community users, to advance genome science in support of the DOE missions of clean bio-energy, carbon cycling, and bioremediation.

  19. Accommodating the Effect of Ancient DNA Damage on Inferences of Demographic Histories

    E-print Network

    Shapiro, Beth

    Department of Computer Science, University of Auckland, Auckland, New Zealand; and §Department of Biology coalescent methods such as those implemented in the software package BEAST can be used to estimate; Ho et al. 2008). To infer demographic history, each of these analyses used the software package BEAST

  20. UNDERSTANDING HOW HARVEST INFLUENCES THE LIFE HISTORY AND DEMOGRAPHICS OF SHOVELNOSE STURGEON IN THE MIDDLE

    E-print Network

    IN THE MIDDLE MISSISSIPPI RIVER by Sara Joy Tripp B.A., Southern Illinois University, 2004 A Thesis Submitted the Life History and Demographics of Shovelnose Sturgeon in the Middle Mississippi River MAJOR PROFESSORS Mississippi River is one of the last commercially viable sturgeon populations in the world. To determine

  1. Patterns of Polymorphism and Demographic History in Natural Populations of Arabidopsis lyrata

    Microsoft Academic Search

    Jeffrey Ross-Ibarra; Stephen I. Wright; John Paul Foxe; Akira Kawabe; Leah Derose-Wilson; Gesseca Gos; Deborah Charlesworth; Brandon S. Gaut; Justin C. Fay

    2008-01-01

    BackgroundMany of the processes affecting genetic diversity act on local populations. However, studies of plant nucleotide diversity have largely ignored local sampling, making it difficult to infer the demographic history of populations and to assess the importance of local adaptation. Arabidopsis lyrata, a self-incompatible, perennial species with a circumpolar distribution, is an excellent model system in which to study the

  2. Demographic Histories, Isolation and Social Factors as Determinants of the Genetic Structure of Alpine Linguistic Groups

    PubMed Central

    Coia, Valentina; Capocasa, Marco; Anagnostou, Paolo; Pascali, Vincenzo; Scarnicci, Francesca; Boschi, Ilaria; Battaggia, Cinzia; Crivellaro, Federica; Ferri, Gianmarco; Alů, Milena; Brisighelli, Francesca; Busby, George B. J.; Capelli, Cristian; Maixner, Frank; Cipollini, Giovanna; Viazzo, Pier Paolo; Zink, Albert; Destro Bisol, Giovanni

    2013-01-01

    Great European mountain ranges have acted as barriers to gene flow for resident populations since prehistory and have offered a place for the settlement of small, and sometimes culturally diverse, communities. Therefore, the human groups that have settled in these areas are worth exploring as an important potential source of diversity in the genetic structure of European populations. In this study, we present new high resolution data concerning Y chromosomal variation in three distinct Alpine ethno-linguistic groups, Italian, Ladin and German. Combining unpublished and literature data on Y chromosome and mitochondrial variation, we were able to detect different genetic patterns. In fact, within and among population diversity values observed vary across linguistic groups, with German and Italian speakers at the two extremes, and seem to reflect their different demographic histories. Using simulations we inferred that the joint effect of continued genetic isolation and reduced founding group size may explain the apportionment of genetic diversity observed in all groups. Extending the analysis to other continental populations, we observed that the genetic differentiation of Ladins and German speakers from Europeans is comparable or even greater to that observed for well known outliers like Sardinian and Basques. Finally, we found that in south Tyroleans, the social practice of Geschlossener Hof, a hereditary norm which might have favored male dispersal, coincides with a significant intra-group diversity for mtDNA but not for Y chromosome, a genetic pattern which is opposite to those expected among patrilocal populations. Together with previous evidence regarding the possible effects of “local ethnicity” on the genetic structure of German speakers that have settled in the eastern Italian Alps, this finding suggests that taking socio-cultural factors into account together with geographical variables and linguistic diversity may help unveil some yet to be understood aspects of the genetic structure of European populations. PMID:24312576

  3. Demographic histories, isolation and social factors as determinants of the genetic structure of Alpine linguistic groups.

    PubMed

    Coia, Valentina; Capocasa, Marco; Anagnostou, Paolo; Pascali, Vincenzo; Scarnicci, Francesca; Boschi, Ilaria; Battaggia, Cinzia; Crivellaro, Federica; Ferri, Gianmarco; Alů, Milena; Brisighelli, Francesca; Busby, George B J; Capelli, Cristian; Maixner, Frank; Cipollini, Giovanna; Viazzo, Pier Paolo; Zink, Albert; Destro Bisol, Giovanni

    2013-01-01

    Great European mountain ranges have acted as barriers to gene flow for resident populations since prehistory and have offered a place for the settlement of small, and sometimes culturally diverse, communities. Therefore, the human groups that have settled in these areas are worth exploring as an important potential source of diversity in the genetic structure of European populations. In this study, we present new high resolution data concerning Y chromosomal variation in three distinct Alpine ethno-linguistic groups, Italian, Ladin and German. Combining unpublished and literature data on Y chromosome and mitochondrial variation, we were able to detect different genetic patterns. In fact, within and among population diversity values observed vary across linguistic groups, with German and Italian speakers at the two extremes, and seem to reflect their different demographic histories. Using simulations we inferred that the joint effect of continued genetic isolation and reduced founding group size may explain the apportionment of genetic diversity observed in all groups. Extending the analysis to other continental populations, we observed that the genetic differentiation of Ladins and German speakers from Europeans is comparable or even greater to that observed for well known outliers like Sardinian and Basques. Finally, we found that in south Tyroleans, the social practice of Geschlossener Hof, a hereditary norm which might have favored male dispersal, coincides with a significant intra-group diversity for mtDNA but not for Y chromosome, a genetic pattern which is opposite to those expected among patrilocal populations. Together with previous evidence regarding the possible effects of "local ethnicity" on the genetic structure of German speakers that have settled in the eastern Italian Alps, this finding suggests that taking socio-cultural factors into account together with geographical variables and linguistic diversity may help unveil some yet to be understood aspects of the genetic structure of European populations. PMID:24312576

  4. How the world survived the population bomb: lessons from 50 years of extraordinary demographic history.

    PubMed

    Lam, David

    2011-11-01

    The world population will reach 7 billion in late 2011, a demographic milestone that is causing renewed attention to the challenges caused by population growth. This article looks at the last 50 years of demographic change, one of the most extraordinary periods in demographic history. During this period, world population grew at rates that have never been seen before and will almost surely never be seen again. There were many concerns about the potential impact of rapid population growth in the 1960s, including mass starvation in countries such as India, depletion of nonrenewable resources, and increased poverty in low-income countries. The actual experience was very different. World food production increased faster than world population in every decade since the 1960s, resource prices fell during most of the period, and poverty declined significantly in much of the developing world. The article considers the economic and demographic explanations for the surprising successes of this important period in demographic history. It also looks at regions that have been less successful, especially Africa, and at the lessons for dealing with the important challenges that still remain. PMID:22005884

  5. How the World Survived the Population Bomb: Lessons From 50 Years of Extraordinary Demographic History

    PubMed Central

    Lam, David

    2012-01-01

    The world population will reach 7 billion in late 2011, a demographic milestone that is causing renewed attention to the challenges caused by population growth. This article looks at the last 50 years of demographic change, one of the most extraordinary periods in demographic history. During this period, world population grew at rates that have never been seen before and will almost surely never be seen again. There were many concerns about the potential impact of rapid population growth in the 1960s, including mass starvation in countries such as India, depletion of nonrenewable resources, and increased poverty in low-income countries. The actual experience was very different. World food production increased faster than world population in every decade since the 1960s, resource prices fell during most of the period, and poverty declined significantly in much of the developing world. The article considers the economic and demographic explanations for the surprising successes of this important period in demographic history. It also looks at regions that have been less successful, especially Africa, and at the lessons for dealing with the important challenges that still remain. PMID:22005884

  6. Effects of recent population bottlenecks on reconstructing the demographic history of prairie-chickens.

    PubMed

    Johnson, Jeff A; Dunn, Peter O; Bouzat, Juan L

    2007-06-01

    Current methods of DNA sequence analysis attempt to reconstruct historical patterns of population structure and growth from contemporary samples. However, these techniques may be influenced by recent population bottlenecks, which have the potential to eliminate lineages that reveal past changes in demography. One way to examine the performance of these demographic methods is to compare samples from populations before and after recent bottlenecks. We compared estimates of demographic history from populations of greater prairie-chickens (Tympanuchus cupido) before and after recent bottlenecks using four common methods (nested clade analysis [NCA], Tajima's D, mismatch distribution, and MDIV). We found that NCA did not perform well in the presence of bottleneck events, although it did recover some genetic signals associated with increased isolation and the extinction of intermediate populations. The majority of estimates for Tajima's D, including those from bottlenecked populations, were not significantly different from zero, suggesting our data conformed to neutral expectations. In contrast, mismatch distributions including the raggedness index were more likely to identify recently bottlenecked populations with this data set. Estimates of population mutation rate (theta), population divergence time (t), and time to the most recent common ancestor (TMRCA) from MDIV were similar before and after bottlenecks; however, estimates of gene flow (M) were significantly lower in a few cases following a bottleneck. These results suggest that caution should be used when assessing demographic history from contemporary data sets, as recently fragmented and bottlenecked populations may have lost lineages that affect inferences of their demographic history. PMID:17561885

  7. Genomic Sequencing of Plasmodium falciparum Malaria Parasites from Senegal Reveals the Demographic History of the Population

    PubMed Central

    Chang, Hsiao-Han; Park, Daniel J.; Galinsky, Kevin J.; Schaffner, Stephen F.; Ndiaye, Daouda; Ndir, Omar; Mboup, Souleymane; Wiegand, Roger C.; Volkman, Sarah K.; Sabeti, Pardis C.; Wirth, Dyann F.; Neafsey, Daniel E.; Hartl, Daniel L.

    2012-01-01

    Malaria is a deadly disease that causes nearly one million deaths each year. To develop methods to control and eradicate malaria, it is important to understand the genetic basis of Plasmodium falciparum adaptations to antimalarial treatments and the human immune system while taking into account its demographic history. To study the demographic history and identify genes under selection more efficiently, we sequenced the complete genomes of 25 culture-adapted P. falciparum isolates from three sites in Senegal. We show that there is no significant population structure among these Senegal sampling sites. By fitting demographic models to the synonymous allele-frequency spectrum, we also estimated a major 60-fold population expansion of this parasite population ?20,000–40,000 years ago. Using inferred demographic history as a null model for coalescent simulation, we identified candidate genes under selection, including genes identified before, such as pfcrt and PfAMA1, as well as new candidate genes. Interestingly, we also found selection against G/C to A/T changes that offsets the large mutational bias toward A/T, and two unusual patterns: similar synonymous and nonsynonymous allele-frequency spectra, and 18% of genes having a nonsynonymous-to-synonymous polymorphism ratio >1. PMID:22734050

  8. Life history and demographic variation in the lizard Sceloporus graciosus: A long-term study

    Microsoft Academic Search

    D. W. Tinkle; A. E. Dunham; J. D. Congdon

    1993-01-01

    An 11-yr study of life history and demographic variation in the sagebrush lizard Sceloporus graciosus was carried out on two study areas (Rattlesnake Ridge and Ponderosa Flat) in the Kolob Mesa Section of Zion National Park, Utah. Two primary objectives of this mark-recapture study were to: (1) quantify variation in age structure, age, and size at maturity, age-specific survivorship and

  9. Multilocus dataset reveals demographic histories of two peat mosses in Europe

    PubMed Central

    Szövényi, Péter; Hock, Zsófia; Schneller, Jakob J; Tóth, Zoltán

    2007-01-01

    Background Revealing the past and present demographic history of populations is of high importance to evaluate the conservation status of species. Demographic data can be obtained by direct monitoring or by analysing data of historical and recent collections. Although these methods provide the most detailed information they are very time consuming. Another alternative way is to make use of the information accumulated in the species' DNA over its history. Recent development of the coalescent theory makes it possible to reconstruct the demographic history of species using nucleotide polymorphism data. To separate the effect of natural selection and demography, multilocus analysis is needed because these two forces can produce similar patterns of polymorphisms. In this study we investigated the amount and pattern of sequence variability of a Europe wide sample set of two peat moss species (Sphagnum fimbriatum and S. squarrosum) with similar distributions and mating systems but presumably contrasting historical demographies using 3 regions of the nuclear genome (appr. 3000 bps). We aimed to draw inferences concerning demographic, and phylogeographic histories of the species. Results All three nuclear regions supported the presence of an Atlantic and Non-Atlantic clade of S. fimbriatum suggesting glacial survival of the species along the Atlantic coast of Europe. Contrarily, S. squarrosum haplotypes showed three clades but no geographic structure at all. Maximum likelihood, mismatch and Bayesian analyses supported a severe historical bottleneck and a relatively recent demographic expansion of the Non-Atlantic clade of S. fimbriatum, whereas size of S. squarrosum populations has probably decreased in the past. Species wide molecular diversity of the two species was nearly the same with an excess of replacement mutations in S. fimbriatum. Similar levels of molecular diversity, contrasting phylogeographic patterns and excess of replacement mutations in S. fimbriatum compared to S. squarrosum mirror unexpected differences in the demography and population history of the species. Conclusion This study represents the first detailed European wide phylodemographic investigation on bryophytes and shows how pattern of nucleotide polymorphism can reveal unexpected differences in the population history of haploid plants with seemingly similar characteristics. PMID:17714592

  10. BA Joint Honours Spanish and Ancient History VR14

    E-print Network

    Harman, Neal.A.

    Joint Honours Spanish and Teaching English as a Foreign Language RX43 CELTA In year 2, the BA TEFL Teaching to Adults (CELTA), a professional qualification for teachers of English as a foreign language language and discover the rich history of Spain, Portugal and Latin America, not to mention the chance

  11. Reconstructing the demographic history of orang-utans using Approximate Bayesian Computation.

    PubMed

    Nater, Alexander; Greminger, Maja P; Arora, Natasha; van Schaik, Carel P; Goossens, Benoit; Singleton, Ian; Verschoor, Ernst J; Warren, Kristin S; Krützen, Michael

    2015-01-01

    Investigating how different evolutionary forces have shaped patterns of DNA variation within and among species requires detailed knowledge of their demographic history. Orang-utans, whose distribution is currently restricted to the South-East Asian islands of Borneo (Pongo pygmaeus) and Sumatra (Pongo abelii), have likely experienced a complex demographic history, influenced by recurrent changes in climate and sea levels, volcanic activities and anthropogenic pressures. Using the most extensive sample set of wild orang-utans to date, we employed an Approximate Bayesian Computation (ABC) approach to test the fit of 12 different demographic scenarios to the observed patterns of variation in autosomal, X-chromosomal, mitochondrial and Y-chromosomal markers. In the best-fitting model, Sumatran orang-utans exhibit a deep split of populations north and south of Lake Toba, probably caused by multiple eruptions of the Toba volcano. In addition, we found signals for a strong decline in all Sumatran populations ~24 ka, probably associated with hunting by human colonizers. In contrast, Bornean orang-utans experienced a severe bottleneck ~135 ka, followed by a population expansion and substructuring starting ~82 ka, which we link to an expansion from a glacial refugium. We showed that orang-utans went through drastic changes in population size and connectedness, caused by recurrent contraction and expansion of rainforest habitat during Pleistocene glaciations and probably hunting by early humans. Our findings emphasize the fact that important aspects of the evolutionary past of species with complex demographic histories might remain obscured when applying overly simplified models. PMID:25439562

  12. Species-Wide Genetic Variation and Demographic History of Drosophila sechellia, a Species Lacking Population Structure

    PubMed Central

    Legrand, Delphine; Tenaillon, Maud I.; Matyot, Pat; Gerlach, Justin; Lachaise, Daniel; Cariou, Marie-Louise

    2009-01-01

    Long-term persistence of species characterized by a reduced effective population size is still a matter of debate that would benefit from the description of new relevant biological models. The island endemic specialist Drosophila sechellia has received considerable attention in evolutionary genetic studies. On the basis of the analysis of a limited number of strains, a handful of studies have reported a strikingly depleted level of genetic variation but little is known about its demographic history. We extended analyses of nucleotide polymorphism in D. sechellia to a species-wide level using 10 nuclear genes sequenced in 10 populations. We confirmed that D. sechellia exhibits little nucleotide-sequence variation. It is characterized by a low effective population size, >10-fold lower than that of D. simulans, which ranks D. sechellia as the least genetically diverse Drosophila species. No obvious population subdivision was detected despite its fragmented geographic distribution on different islands. We used approximate Bayesian computation (ABC) to test for demographic scenarios compatible with the geological history of the Seychelles and the ecology of D. sechellia. We found that while bottlenecks cannot account for the pattern of molecular evolution observed in this species, scenarios close to the null hypothesis of a constant population size are well supported. We discuss these findings with regard to adaptive features specific to D. sechellia and its life-history strategy. PMID:19506309

  13. The Confounding Effect of Population Structure on Bayesian Skyline Plot Inferences of Demographic History

    PubMed Central

    Heller, Rasmus; Chikhi, Lounes; Siegismund, Hans Redlef

    2013-01-01

    Many coalescent-based methods aiming to infer the demographic history of populations assume a single, isolated and panmictic population (i.e. a Wright-Fisher model). While this assumption may be reasonable under many conditions, several recent studies have shown that the results can be misleading when it is violated. Among the most widely applied demographic inference methods are Bayesian skyline plots (BSPs), which are used across a range of biological fields. Violations of the panmixia assumption are to be expected in many biological systems, but the consequences for skyline plot inferences have so far not been addressed and quantified. We simulated DNA sequence data under a variety of scenarios involving structured populations with variable levels of gene flow and analysed them using BSPs as implemented in the software package BEAST. Results revealed that BSPs can show false signals of population decline under biologically plausible combinations of population structure and sampling strategy, suggesting that the interpretation of several previous studies may need to be re-evaluated. We found that a balanced sampling strategy whereby samples are distributed on several populations provides the best scheme for inferring demographic change over a typical time scale. Analyses of data from a structured African buffalo population demonstrate how BSP results can be strengthened by simulations. We recommend that sample selection should be carefully considered in relation to population structure previous to BSP analyses, and that alternative scenarios should be evaluated when interpreting signals of population size change. PMID:23667558

  14. Demographic history of an elusive carnivore: using museums to inform management

    PubMed Central

    Holbrook, Joseph D; DeYoung, Randy W; Tewes, Michael E; Young, John H

    2012-01-01

    Elusive carnivores present a challenge to managers because traditional survey methods are not suitable. We applied a genetic approach using museum specimens to examine how historical and recent conditions influenced the demographic history of Puma concolor in western and southern Texas, USA. We used 10 microsatellite loci and indexed population trends by estimating historical and recent genetic diversity, genetic differentiation and effective population size. Mountain lions in southern Texas exhibited a 9% decline in genetic diversity, whereas diversity remained stable in western Texas. Genetic differentiation between western and southern Texas was minimal historically (FST = 0.04, P < 0.01), but increased 2–2.5 times in our recent sample. An index of genetic drift for southern Texas was seven to eight times that of western Texas, presumably contributing to the current differentiation between western and southern Texas. Furthermore, southern Texas exhibited a >50% temporal decline in effective population size, whereas western Texas showed no change. Our results illustrate that population declines and genetic drift have occurred in southern Texas, likely because of contemporary habitat loss and predator control. Population monitoring may be needed to ensure the persistence of mountain lions in the southern Texas region. This study highlights the utility of sampling museum collections to examine demographic histories and inform wildlife management. PMID:23028402

  15. Demographic history of an elusive carnivore: using museums to inform management.

    PubMed

    Holbrook, Joseph D; Deyoung, Randy W; Tewes, Michael E; Young, John H

    2012-09-01

    Elusive carnivores present a challenge to managers because traditional survey methods are not suitable. We applied a genetic approach using museum specimens to examine how historical and recent conditions influenced the demographic history of Puma concolor in western and southern Texas, USA. We used 10 microsatellite loci and indexed population trends by estimating historical and recent genetic diversity, genetic differentiation and effective population size. Mountain lions in southern Texas exhibited a 9% decline in genetic diversity, whereas diversity remained stable in western Texas. Genetic differentiation between western and southern Texas was minimal historically (F(ST) = 0.04, P < 0.01), but increased 2-2.5 times in our recent sample. An index of genetic drift for southern Texas was seven to eight times that of western Texas, presumably contributing to the current differentiation between western and southern Texas. Furthermore, southern Texas exhibited a >50% temporal decline in effective population size, whereas western Texas showed no change. Our results illustrate that population declines and genetic drift have occurred in southern Texas, likely because of contemporary habitat loss and predator control. Population monitoring may be needed to ensure the persistence of mountain lions in the southern Texas region. This study highlights the utility of sampling museum collections to examine demographic histories and inform wildlife management. PMID:23028402

  16. Demographic and phylogeographic histories of two venomous North American snakes of the genus Agkistrodon.

    PubMed

    Guiher, Timothy J; Burbrink, Frank T

    2008-08-01

    Many studies have revealed that lineages currently inhabiting formerly glaciated areas were pushed into southern glacial refugia and have expanded into their modern range since the last glacial maximum. There have been few studies that compare the effects of glacial cycles on lineage diversification and historical demography in closely related species with overlapping ranges. In this study we compare phylogeographic structure, historical demography, and approximate lineage age in two closely related and broadly co-occurring venomous snakes in eastern North America, the cottonmouth (Agkistrodon piscivorus) and copperhead (A. contortrix) using sequences from the mtDNA gene cytochrome b. We inferred three geographic lineages of A. contortrix and two of A. piscivorus with no common geographic or temporal pattern of lineage diversification identified for these species. Lineage diversification occurred in the Late Pliocene for A. piscivorus (approximately 2.5mya) and in the Early Pleistocene for A. contortrix ( approximately 1.5mya). Demographic estimates revealed population expansion following the last glacial maximum (approximately 20,000 years ago) in two lineages of A. contortrix (the Central clade and Eastern clade) and one lineage of A. piscivorus (the Continental clade). The Florida clade of A. piscivorus is the only lineage for which constant population size through time was inferred, possibly due to stable populations persisting in areas unaffected by glacial advances. Our data suggest that unique habitat preferences may have shaped both the phylogeographic and demographic histories of each species. PMID:18539486

  17. Life history and demographic variation in the lizard Sceloporus graciosus: A long-term study

    SciTech Connect

    Tinkle, D.W. (Univ. of Michigan, Ann Arbor, MI (United States)); Dunham, A.E. (Univ. of Pennsylvania, Philadelphia, PA (United States)); Congdon, J.D. (Savannah River Ecology Lab., Aiken, SC (United States))

    1993-12-01

    An 11-yr study of life history and demographic variation in the sagebrush lizard Sceloporus graciosus was carried out on two study areas (Rattlesnake Ridge and Ponderosa Flat) in the Kolob Mesa Section of Zion National Park, Utah. Two primary objectives of this mark-recapture study were to: (1) quantify variation in age structure, age, and size at maturity, age-specific survivorship and fecundity, and individual growth rates, and (2) conduct a series of density reduction experiments designed to elucidate the effects of density on growth rates and survival of posthatchling lizards. In addition, the authors examined the relationships of variation in population density and deviation from long-term average precipitation and temperature to variation in individual growth, reproduction, and demography. 43 refs., 5 figs., 11 tabs.

  18. Whole-genome sequencing of giant pandas provides insights into demographic history and local adaptation.

    PubMed

    Zhao, Shancen; Zheng, Pingping; Dong, Shanshan; Zhan, Xiangjiang; Wu, Qi; Guo, Xiaosen; Hu, Yibo; He, Weiming; Zhang, Shanning; Fan, Wei; Zhu, Lifeng; Li, Dong; Zhang, Xuemei; Chen, Quan; Zhang, Hemin; Zhang, Zhihe; Jin, Xuelin; Zhang, Jinguo; Yang, Huanming; Wang, Jian; Wang, Jun; Wei, Fuwen

    2013-01-01

    The panda lineage dates back to the late Miocene and ultimately leads to only one extant species, the giant panda (Ailuropoda melanoleuca). Although global climate change and anthropogenic disturbances are recognized to shape animal population demography their contribution to panda population dynamics remains largely unknown. We sequenced the whole genomes of 34 pandas at an average 4.7-fold coverage and used this data set together with the previously deep-sequenced panda genome to reconstruct a continuous demographic history of pandas from their origin to the present. We identify two population expansions, two bottlenecks and two divergences. Evidence indicated that, whereas global changes in climate were the primary drivers of population fluctuation for millions of years, human activities likely underlie recent population divergence and serious decline. We identified three distinct panda populations that show genetic adaptation to their environments. However, in all three populations, anthropogenic activities have negatively affected pandas for 3,000 years. PMID:23242367

  19. Exploring the demographic history of DNA sequences using the generalized skyline plot.

    PubMed

    Strimmer, K; Pybus, O G

    2001-12-01

    We present an intuitive visual framework, the generalized skyline plot, to explore the demographic history of sampled DNA sequences. This approach is based on a genealogy inferred from the sequences and provides a nonparametric estimate of effective population size through time. In contrast to previous related procedures, the generalized skyline plot is more applicable to cases where the underlying tree is not fully resolved and the data is not highly variable. This is achieved by the grouping of adjacent coalescent intervals. We employ a small-sample Akaike information criterion to objectively choose the optimal grouping strategy. We investigate the performance of our approach using simulation and subsequently apply it to HIV-1 sequences from central Africa and mtDNA sequences from red pandas. PMID:11719579

  20. Neutral nuclear variation in Baboons (genus Papio) provides insights into their evolutionary and demographic histories.

    PubMed

    Boissinot, Stéphane; Alvarez, Lauren; Giraldo-Ramirez, Juliana; Tollis, Marc

    2014-12-01

    Baboons (genus Papio) are distributed over most of sub-Saharan Africa and in the southern portion of the Arabian Peninsula. Six distinct morphotypes, with clearly defined geographic distributions, are recognized (the olive, chacma, yellow, Guinea, Kinda, and hamadryas baboons). The evolutionary relationships among baboon forms have long been a controversial issue. Phylogenetic analyses based on mitochondrial DNA sequences revealed that the modern baboon morphotypes are mitochondrially paraphyletic or polyphyletic. The discordance between mitochondrial lineages and morphology is indicative of extensive introgressive hybridization between ancestral baboon populations. To gain insights into the evolutionary relationships among morphotypes and their demographic history, we performed an analysis of nuclear variation in baboons. We sequenced 13 noncoding, putatively neutral, nuclear regions, and scored the presence/absence of 18 polymorphic transposable elements in a sample of 45 baboons belonging to five of the six recognized baboon forms. We found that the chacma baboon is the sister-taxon to all other baboons and the yellow baboon is the sister-taxon to an unresolved northern clade containing the olive, Guinea, and hamadryas baboons. We estimated that the diversification of baboons occurred entirely in the Pleistocene, the earliest split dating ?1.5 million years ago, and that baboons have experienced relatively large and constant effective population sizes for most of their evolutionary history (?30,000 to 95,000 individuals). PMID:25234435

  1. Population genetic structure and demographic history of Atrina pectinata based on mitochondrial DNA and microsatellite markers.

    PubMed

    Xue, Dong-Xiu; Wang, Hai-Yan; Zhang, Tao; Liu, Jin-Xian

    2014-01-01

    The pen shell, Atrina pectinata, is one of the commercial bivalves in East Asia and thought to be recently affected by anthropogenic pressure (habitat destruction and/or fishing pressure). Information on its population genetic structure is crucial for the conservation of A. pectinata. Considering its long pelagic larval duration and iteroparity with high fecundity, the genetic structure for A. pectinata could be expected to be weak at a fine scale. However, the unusual oceanography in the coasts of China and Korea suggests potential for restricted dispersal of pelagic larvae and geographical differentiation. In addition, environmental changes associated with Pleistocene sea level fluctuations on the East China Sea continental shelf may also have strongly influenced historical population demography and genetic diversity of marine organisms. Here, partial sequences of the mitochondrial Cytochrome c oxidase subunit I (COI) gene and seven microsatellite loci were used to estimate population genetic structure and demographic history of seven samples from Northern China coast and one sample from North Korea coast. Despite high levels of genetic diversity within samples, there was no genetic differentiation among samples from Northern China coast and low but significant genetic differentiation between some of the Chinese samples and the North Korean sample. A late Pleistocene population expansion, probably after the Last Glacial Maximum, was also demonstrated for A. pectinata samples. No recent genetic bottleneck was detected in any of the eight samples. We concluded that both historical recolonization (through population range expansion and demographic expansion in the late Pleistocene) and current gene flow (through larval dispersal) were responsible for the weak level of genetic structure detected in A. pectinata. PMID:24789175

  2. Population Genetic Structure and Demographic History of Atrina pectinata Based on Mitochondrial DNA and Microsatellite Markers

    PubMed Central

    Xue, Dong-Xiu; Wang, Hai-Yan; Zhang, Tao; Liu, Jin-Xian

    2014-01-01

    The pen shell, Atrina pectinata, is one of the commercial bivalves in East Asia and thought to be recently affected by anthropogenic pressure (habitat destruction and/or fishing pressure). Information on its population genetic structure is crucial for the conservation of A. pectinata. Considering its long pelagic larval duration and iteroparity with high fecundity, the genetic structure for A. pectinata could be expected to be weak at a fine scale. However, the unusual oceanography in the coasts of China and Korea suggests potential for restricted dispersal of pelagic larvae and geographical differentiation. In addition, environmental changes associated with Pleistocene sea level fluctuations on the East China Sea continental shelf may also have strongly influenced historical population demography and genetic diversity of marine organisms. Here, partial sequences of the mitochondrial Cytochrome c oxidase subunit I (COI) gene and seven microsatellite loci were used to estimate population genetic structure and demographic history of seven samples from Northern China coast and one sample from North Korea coast. Despite high levels of genetic diversity within samples, there was no genetic differentiation among samples from Northern China coast and low but significant genetic differentiation between some of the Chinese samples and the North Korean sample. A late Pleistocene population expansion, probably after the Last Glacial Maximum, was also demonstrated for A. pectinata samples. No recent genetic bottleneck was detected in any of the eight samples. We concluded that both historical recolonization (through population range expansion and demographic expansion in the late Pleistocene) and current gene flow (through larval dispersal) were responsible for the weak level of genetic structure detected in A. pectinata. PMID:24789175

  3. Genetic population structuring and demographic history of red spotted grouper (Epinephelus akaara) in South and East China Sea

    Microsoft Academic Search

    Shengping Chen; Tao Liu; Zufu Li; Tianxiang Gao

    2008-01-01

    Climatic oscillations during the Pleistocene ice ages in the Northwestern Pacific produced great changes in species' geographical distribution and abundance, which could be expected to have genetic consequences in marine fishes. In order to estimate the demographic history and genetic structure of Epinephelus akaara in South and East China Sea, 87 individuals were sampled from 7 localities throughout the distribution

  4. -Demographic and life-history correlates for Amazonian trees -625 Journal of Vegetation Science 16: 625-634, 2005

    E-print Network

    Bermingham, Eldredge

    -ha permanent plots, eight characteristics were estimated for each species: wood density, annual and successional sta- tus, and the second gradient related to tree size. Along these gradients, four relatively demographic and life-history traits, such as those that distinguish early and late successional species

  5. Demographic histories and genetic diversities of Fennoscandian marine and landlocked ringed seal subspecies

    PubMed Central

    Nyman, Tommi; Valtonen, Mia; Aspi, Jouni; Ruokonen, Minna; Kunnasranta, Mervi; Palo, Jukka U

    2014-01-01

    Island populations are on average smaller, genetically less diverse, and at a higher risk to go extinct than mainland populations. Low genetic diversity may elevate extinction probability, but the genetic component of the risk can be affected by the mode of diversity loss, which, in turn, is connected to the demographic history of the population. Here, we examined the history of genetic erosion in three Fennoscandian ringed seal subspecies, of which one inhabits the Baltic Sea ‘mainland’ and two the ‘aquatic islands’ composed of Lake Saimaa in Finland and Lake Ladoga in Russia. Both lakes were colonized by marine seals after their formation c. 9500 years ago, but Lake Ladoga is larger and more contiguous than Lake Saimaa. All three populations suffered dramatic declines during the 20th century, but the bottleneck was particularly severe in Lake Saimaa. Data from 17 microsatellite loci and mitochondrial control-region sequences show that Saimaa ringed seals have lost most of the genetic diversity present in their Baltic ancestors, while the Ladoga population has experienced only minor reductions. Using Approximate Bayesian computing analyses, we show that the genetic uniformity of the Saimaa subspecies derives from an extended founder event and subsequent slow erosion, rather than from the recent bottleneck. This suggests that the population has persisted for nearly 10,000 years despite having low genetic variation. The relatively high diversity of the Ladoga population appears to result from a high number of initial colonizers and a high post-colonization population size, but possibly also by a shorter isolation period and/or occasional gene flow from the Baltic Sea. PMID:25535558

  6. Diversification, Biogeographic Pattern, and Demographic History of Taiwanese Scutellaria Species Inferred from Nuclear and Chloroplast DNA

    PubMed Central

    Liao, Pei-Chun

    2012-01-01

    The ragged topography created by orogenesis generates diversified habitats for plants in Taiwan. In addition to colonization from nearby mainland China, high species diversity and endemism of plants is also present in Taiwan. Five of the seven Scutellaria species (Lamiaceae) in Taiwan, for example, are endemic to the island. Hypotheses of multiple sources or in situ radiation have arisen to explain the high endemism of Taiwanese species. In this study, phylogenetic analyses using both nuclear and chloroplast markers revealed the multiple sources of Taiwanese Scutellaria species and confirmed the rapid and recent speciation of endemic species, especially those of the “indica group” composed of S. indica, S. austrotaiwanensis, S. tashiroi, and S. playfairii. The common ancestors of the indica group colonized first in northern Taiwan and dispersed regionally southward and eastward. Climate changes during glacial/interglacial cycles led to gradual colonization and variance events in the ancestors of these species, resulting in the present distribution and genetic differentiation of extant populations. Population decline was also detected in S. indica, which might reflect a bottleneck effect from the glacials. In contrast, the recently speciated endemic members of the indica group have not had enough time to accumulate much genetic variation and are thus genetically insensitive to demographic fluctuations, but the extant lineages were spatially expanded in the coalescent process. This study integrated phylogenetic and population genetic analyses to illustrate the evolutionary history of Taiwanese Scutellaria of high endemism and may be indicative of the diversification mechanism of plants on continental islands. PMID:23226402

  7. Shipwrecks and founder effects: divergent demographic histories reflected in Caribbean mtDNA.

    PubMed

    Salas, Antonio; Richards, Martin; Lareu, María-Victoria; Sobrino, Beatriz; Silva, Sandra; Matamoros, Mireya; Macaulay, Vincent; Carracedo, Angel

    2005-12-01

    During the period of the Atlantic slave trade (15th-19th centuries), millions of people were forced to move from Africa to many American destinations, changing dramatically the human landscape of the Americas. Here, we analyze mitochondrial DNA from two different American populations with African ancestry, with hitherto unknown European and Native American components. On the basis of historical records, African-Americans from Chocó (Colombia) and the Garífunas (or "Black Carib") of Honduras are likely to have had very different demographic histories, with a significant founder effect in the formation of the latter. Both the common features and differences are reflected in their mtDNA composition. Both show a minor component (approximately 16%) from Native Central/South Americans and a larger component (approximately 84%) from sub-Saharan Africans. The latter component is very diverse in the African-Americans from Chocó, similar to that of sub-Saharan Africans, but much less so in the Garífunas, with several mtDNA types elevated to high frequency, suggesting the action of genetic drift. PMID:16047324

  8. Demographic History of a Recent Invasion of House Mice on the Isolated Island of Gough

    PubMed Central

    Gray, Melissa M.; Wegmann, Daniel; Haasl, Ryan J.; White, Michael A.; Gabriel, Sofia I.; Searle, Jeremy B.; Cuthbert, Richard J.; Ryan, Peter G.; Payseur, Bret A.

    2014-01-01

    Island populations provide natural laboratories for studying key contributors to evolutionary change, including natural selection, population size, and the colonization of new environments. The demographic histories of island populations can be reconstructed from patterns of genetic diversity. House mice (Mus musculus) inhabit islands throughout the globe, making them an attractive system for studying island colonization from a genetic perspective. Gough Island, in the central South Atlantic Ocean, is one of the remotest islands in the world. House mice were introduced to Gough Island by sealers during the 19th century, and display unusual phenotypes, including exceptionally large body size and carnivorous feeding behavior. We describe genetic variation in Gough Island mice using mitochondrial sequences, nuclear sequences, and microsatellites. Phylogenetic analysis of mitochondrial sequences suggested that Gough Island mice belong to Mus musculus domesticus, with the maternal lineage possibly originating in England or France. Cluster analyses of microsatellites revealed genetic membership for Gough Island mice in multiple coastal populations in Western Europe, suggesting admixed ancestry. Gough Island mice showed substantial reductions in mitochondrial and nuclear sequence variation and weak reductions in microsatellite diversity compared with Western European populations, consistent with a population bottleneck. Approximate Bayesian Computation (ABC) estimated that mice recently colonized Gough Island (~100 years ago) and experienced a 98% reduction in population size followed by a rapid expansion. Our results indicate that the unusual phenotypes of Gough Island mice evolved rapidly, positioning these mice as useful models for understanding rapid phenotypic evolution. PMID:24617968

  9. Effect of Population Reduction on mtDNA Diversity and Demographic History of Korean Cattle Populations.

    PubMed

    Dadi, Hailu; Lee, Seung-Hwan; Jung, Kyoung Sup; Choi, Jae Won; Ko, Moon-Suck; Han, Young-Joon; Kim, Jong-Joo; Kim, Kwan-Suk

    2012-09-01

    The population sizes of three Korean indigenous cattle populations have been drastically reduced over the past decades. In this study, we examined the extent to which reduction in populations influenced genetic diversity, population structure and demographic history using complete mitochondrial DNA (mtDNA) control region sequences. The complete mtDNA control region was sequenced in 56 individuals from Korean Black (KB), Jeju Black (JEB) and Korean Brindle (BRI) cattle populations. We included 27 mtDNA sequences of Korean Brown (BRO) from the GenBank database. Haplotype diversity estimate for the total population was high (0.870) while nucleotide diversity was low (0.004). The KB showed considerably low nucleotide (? = 0.001) and haplotype (h = 0.368) diversities. Analysis of molecular variance revealed a low level of genetic differentiation but this was highly significant (p<0.001) among the cattle populations. Of the total genetic diversity, 7.6% was attributable to among cattle populations diversity and the rest (92.4%) to differences within populations. The mismatch distribution analysis and neutrality tests revealed that KB population was in genetic equilibrium or decline. Indeed, unless an appropriate breeding management practice is developed, inbreeding and genetic drift will further impoverish genetic diversity of these cattle populations. Rational breed development and conservation strategy is needed to safeguard these cattle population. PMID:25049684

  10. Demographic divergence history of pied flycatcher and collared flycatcher inferred from whole-genome re-sequencing data.

    PubMed

    Nadachowska-Brzyska, Krystyna; Burri, Reto; Olason, Pall I; Kawakami, Takeshi; Smeds, Linnéa; Ellegren, Hans

    2013-11-01

    Profound knowledge of demographic history is a prerequisite for the understanding and inference of processes involved in the evolution of population differentiation and speciation. Together with new coalescent-based methods, the recent availability of genome-wide data enables investigation of differentiation and divergence processes at unprecedented depth. We combined two powerful approaches, full Approximate Bayesian Computation analysis (ABC) and pairwise sequentially Markovian coalescent modeling (PSMC), to reconstruct the demographic history of the split between two avian speciation model species, the pied flycatcher and collared flycatcher. Using whole-genome re-sequencing data from 20 individuals, we investigated 15 demographic models including different levels and patterns of gene flow, and changes in effective population size over time. ABC provided high support for recent (mode 0.3 my, range <0.7 my) species divergence, declines in effective population size of both species since their initial divergence, and unidirectional recent gene flow from pied flycatcher into collared flycatcher. The estimated divergence time and population size changes, supported by PSMC results, suggest that the ancestral species persisted through one of the glacial periods of middle Pleistocene and then split into two large populations that first increased in size before going through severe bottlenecks and expanding into their current ranges. Secondary contact appears to have been established after the last glacial maximum. The severity of the bottlenecks at the last glacial maximum is indicated by the discrepancy between current effective population sizes (20,000-80,000) and census sizes (5-50 million birds) of the two species. The recent divergence time challenges the supposition that avian speciation is a relatively slow process with extended times for intrinsic postzygotic reproductive barriers to evolve. Our study emphasizes the importance of using genome-wide data to unravel tangled demographic histories. Moreover, it constitutes one of the first examples of the inference of divergence history from genome-wide data in non-model species. PMID:24244198

  11. BA Joint Honours History and American Studies (3 years) VT17

    E-print Network

    Harman, Neal.A.

    of the historical documents left behind, which range from the chronicle of the medieval world to the Hollywood filmsBA Joint Honours History and American Studies (3 years) VT17 American Studies (4 years) TV71 Ancient History (3 years) V110 Ancient History (4 years) V190 Classical Civilisation (3 years) QV81

  12. Comparative Evaluation of a Joint Lecture-Discussion Approach to U. S. History.

    ERIC Educational Resources Information Center

    Hinrichsen, Keith A.; Schaumburg, Gary F.

    In fall 1970 several sections of a one-semester required U.S. history course (History 27: American History and Constitution) at Cerritos College (California) were combined into a joint lecture-discussion (JL) for 200 or more students. The opportunities for providing two lecturers stressing their topical specialties in group discussions seemed…

  13. Population structure and demographic history of a tropical lowland rainforest tree species Shorea parvifolia (Dipterocarpaceae) from Southeastern Asia

    PubMed Central

    Iwanaga, Hiroko; Teshima, Kosuke M; Khatab, Ismael A; Inomata, Nobuyuki; Finkeldey, Reiner; Siregar, Iskandar Z; Siregar, Ulfah J; Szmidt, Alfred E

    2012-01-01

    Distribution of tropical rainforests in Southeastern Asia has changed over geo-logical time scale, due to movement of tectonic plates and/or global climatic changes. Shorea parvifolia is one of the most common tropical lowland rainforest tree species in Southeastern Asia. To infer population structure and demographic history of S. parvifolia, as indicators of temporal changes in the distribution and extent of tropical rainforest in this region, we studied levels and patterns of nucleotide polymorphism in the following five nuclear gene regions: GapC, GBSSI, PgiC, SBE2, and SODH. Seven populations from peninsular Malaysia, Sumatra, and eastern Borneo were included in the analyses. STRUCTURE analysis revealed that the investigated populations are divided into two groups: Sumatra-Malay and Borneo. Furthermore, each group contained one admixed population. Under isolation with migration model, divergence of the two groups was estimated to occur between late Pliocene (2.6 MYA) and middle Pleistocene (0.7 MYA). The log-likelihood ratio tests of several demographic models strongly supported model with population expansion and low level of migration after divergence of the Sumatra-Malay and Borneo groups. The inferred demographic history of S. parvifolia suggested the presence of a scarcely forested land bridge on the Sunda Shelf during glacial periods in the Pleistocene and predominance of tropical lowland rainforest at least in Sumatra and eastern Borneo. PMID:22957170

  14. Population structure and demographic history of a tropical lowland rainforest tree species Shorea parvifolia (Dipterocarpaceae) from Southeastern Asia.

    PubMed

    Iwanaga, Hiroko; Teshima, Kosuke M; Khatab, Ismael A; Inomata, Nobuyuki; Finkeldey, Reiner; Siregar, Iskandar Z; Siregar, Ulfah J; Szmidt, Alfred E

    2012-07-01

    Distribution of tropical rainforests in Southeastern Asia has changed over geo-logical time scale, due to movement of tectonic plates and/or global climatic changes. Shorea parvifolia is one of the most common tropical lowland rainforest tree species in Southeastern Asia. To infer population structure and demographic history of S. parvifolia, as indicators of temporal changes in the distribution and extent of tropical rainforest in this region, we studied levels and patterns of nucleotide polymorphism in the following five nuclear gene regions: GapC, GBSSI, PgiC, SBE2, and SODH. Seven populations from peninsular Malaysia, Sumatra, and eastern Borneo were included in the analyses. STRUCTURE analysis revealed that the investigated populations are divided into two groups: Sumatra-Malay and Borneo. Furthermore, each group contained one admixed population. Under isolation with migration model, divergence of the two groups was estimated to occur between late Pliocene (2.6 MYA) and middle Pleistocene (0.7 MYA). The log-likelihood ratio tests of several demographic models strongly supported model with population expansion and low level of migration after divergence of the Sumatra-Malay and Borneo groups. The inferred demographic history of S. parvifolia suggested the presence of a scarcely forested land bridge on the Sunda Shelf during glacial periods in the Pleistocene and predominance of tropical lowland rainforest at least in Sumatra and eastern Borneo. PMID:22957170

  15. Mating-System Variation, Demographic History and Patterns of Nucleotide Diversity in the Tristylous Plant Eichhornia paniculata

    PubMed Central

    Ness, Rob W.; Wright, Stephen I.; Barrett, Spencer C. H.

    2010-01-01

    Inbreeding in highly selfing populations reduces effective size and, combined with demographic conditions associated with selfing, this can erode genetic diversity and increase population differentiation. Here we investigate the role that variation in mating patterns and demographic history play in shaping the distribution of nucleotide variation within and among populations of the annual neotropical colonizing plant Eichhornia paniculata, a species with wide variation in selfing rates. We sequenced 10 EST-derived nuclear loci in 225 individuals from 25 populations sampled from much of the geographic range and used coalescent simulations to investigate demographic history. Highly selfing populations exhibited moderate reductions in diversity but there was no significant difference in variation between outcrossing and mixed mating populations. Population size interacted strongly with mating system and explained more of the variation in diversity within populations. Bayesian structure analysis revealed strong regional clustering and selfing populations were highly differentiated on the basis of an analysis of Fst. There was no evidence for a significant loss of within-locus linkage disequilibrium within populations, but regional samples revealed greater breakdown in Brazil than in selfing populations from the Caribbean. Coalescent simulations indicate a moderate bottleneck associated with colonization of the Caribbean from Brazil ?125,000 years before the present. Our results suggest that the recent multiple origins of selfing in E. paniculata from diverse outcrossing populations result in higher diversity than expected under long-term equilibrium. PMID:19917767

  16. Lifeboat versus corporate ethic: social and demographic implications of stem and joint families.

    PubMed

    Das Gupta, M

    1999-07-01

    We contrast stem and joint family systems, to show how differences in norms of inheritance and residence profoundly influence our values and social constructs. They shape how people evaluate each other and patterns of conflict and cooperation within and between generations. Through this, they influence many fundamental aspects of social organization and behaviour. These influence health outcomes through categorizing people into those whose health is encouraged to prosper or to fail. It also influences a wide range of other outcomes, including strategies of household resource management; migration; ways of exploiting commercial opportunities and the operation of civil society. A number of hypotheses are developed about the nature of these interrelationships, some of which are substantiated empirically and others which can be tested. PMID:10414827

  17. Genetic structure and demographic history of the endangered and endemic schizothoracine fish Gymnodiptychus pachycheilus in Qinghai-Tibetan Plateau.

    PubMed

    Su, Junhu; Ji, Weihong; Wei, Yanming; Zhang, Yanping; Gleeson, Dianne M; Lou, Zhongyu; Ren, Jing

    2014-08-01

    The endangered schizothoracine fish Gymnodiptychus pachycheilus is endemic to the Qinghai-Tibetan Plateau (QTP), but very little genetic information is available for this species. Here, we accessed the current genetic divergence of G. pachycheilus population to evaluate their distributions modulated by contemporary and historical processes. Population structure and demographic history were assessed by analyzing 1811-base pairs of mitochondrial DNA from 61 individuals across a large proportion of its geographic range. Our results revealed low nucleotide diversity, suggesting severe historical bottleneck events. Analyses of molecular variance and the conventional population statistic FST (0.0435, P = 0.0215) confirmed weak genetic structure. The monophyly of G. pachycheilus was statistically well-supported, while two divergent evolutionary clusters were identified by phylogenetic analyses, suggesting a microgeographic population structure. The consistent scenario of recent population expansion of two clusters was identified based on several complementary analyses of demographic history (0.096 Ma and 0.15 Ma). This genetic divergence and evolutionary process are likely to have resulted from a series of drainage arrangements triggered by the historical tectonic events of the region. The results obtained here provide the first insights into the evolutionary history and genetic status of this little-known fish. PMID:25088592

  18. Reproductive Demographics and Early Life History of the Shovelnose Sturgeon (SCAPHIRHYNCHUS PLATORYNCHUS)

    Microsoft Academic Search

    Robert E. Colombo

    1998-01-01

    Due to the collapse of the historic caviar fisheries in the Volga River and Caspian Sea, the demand on domestically produced caviar has increased. To supply the increased demand, the harvest of the shovelnose sturgeon Scaphirhynchus latorynchus has increased. Because caviar fisheries preferentially harvest females, information regardingthe sexual demographics of these populations is essential for effective fisheries management. To date,

  19. Effects of recent population bottlenecks on reconstructing the demographic history of prairie-chickens

    Microsoft Academic Search

    JEFF A. J OHNSON; PETER O. DUNN; JUAN L. B OUZAT

    2007-01-01

    Current methods of DNA sequence analysis attempt to reconstruct historical patterns of population structure and growth from contemporary samples. However, these techniques may be influenced by recent population bottlenecks, which have the potential to eliminate lineages that reveal past changes in demography. One way to examine the performance of these demographic methods is to compare samples from populations before and

  20. Uptake of HPV Vaccine: Demographics, Sexual History and Values, Parenting Style, and Vaccine Attitudes

    Microsoft Academic Search

    Susan L. Rosenthal; Richard Rupp; Gregory D. Zimet; Heather M. Mezaa; Melissa L. Lozaa; Mary B. Short; Paul A. Succop

    Purpose: To examine the relationships of demographics, parenting, and vaccine attitudes with the accep- tance of the human papillomavirus (HPV) vaccine or to the intent to vaccinate in the next 12 months. Methods: Mothers (n 153) with daughters ages 11 to 17 years were recruited through the pediatric clinic waiting room\\/announcements to complete a questionnaire. Results: Eighteen percent of the

  1. United States -- Mexican joint ventures: A case history approach

    SciTech Connect

    Moore, N.L.; Chidester, R.J.; Hughes, K.R.; Fowler, R.A.

    1993-03-01

    Because the Mexican government has encouraged investment in Mexico by increasing the percentage of ownership of a Mexican business that a US company can hold, joint ventures are more attractive now than they had been in the past. This study provides preliminary information for US renewable energy companies who are interested in forming a joint venture with a Mexican company. This report is not intended to be a complete reference but does identifies a number of important factors that should be observed when forming a Mexican joint venture: (1)Successful joint ventures achieve the goals of each partner. (2)It is essential that all parties agree to the allocation of responsibilities. (3)Put everything in writing. (4)Research in depth the country or countries in which you are considering doing business.

  2. Genetic structure and demographic history of Colletotrichum gloeosporioides sensu lato and C. truncatum isolates from Trinidad and Mexico

    PubMed Central

    2013-01-01

    Background C. gloeosporioides sensu lato is one of the most economically important post-harvest diseases affecting papaya production worldwide. There is currently no information concerning the genetic structure or demographic history of this pathogen in any of the affected countries. Knowledge of molecular demographic parameters for different populations will improve our understanding of the biogeographic history as well as the evolutionary and adaptive potential of these pathogens. In this study, sequence data for ACT, GPDH, ?-TUB and ITS gene regions were analyzed for C. gloeosporioides sensu lato and C. truncatum isolates infecting papaya in Trinidad and Mexico in order to determine the genetic structure and demographic history of these populations. Results The data indicated that Mexico is the ancestral C. gloeosporioides sensu lato population with asymmetrical migration to Trinidad. Mexico also had the larger effective population size but, both Mexico and Trinidad populations exhibited population expansion. Mexico also had greater nucleotide diversity and high levels of diversity for each gene. There was significant sub-division of the Trinidad and Mexico populations and low levels of genetic divergence among populations for three of the four gene regions; ?-TUB was shown to be under positive selection. There were also dissimilar haplotype characteristics for both populations. Mutation may play a role in shaping the population structure of C. gloeosporioides sensu lato isolates from Trinidad and from Mexico, especially with respect to the ACT and GPDH gene regions. There was no evidence of gene flow between the C. truncatum populations and it is possible that the Mexico and Trinidad populations emerged independently of each other. Conclusions The study revealed relevant information based on the genetic structure as well as the demographic history of two fungal pathogens infecting papaya, C. gloeosporioides sensu lato and C. truncatum, in Trinidad and Mexico. Understanding the genetic structure of pathogen populations will assist in determining the evolutionary potential of the pathogen and in identifying which evolutionary forces may have the greatest impact on durability of resistance. Intervention strategies that target these evolutionary forces would prove to be the most practical. PMID:23800297

  3. Impact of Quaternary climatic changes and interspecific competition on the demographic history of a highly mobile generalist carnivore, the coyote.

    PubMed

    Koblmüller, Stephan; Wayne, Robert K; Leonard, Jennifer A

    2012-08-23

    Recurrent cycles of climatic change during the Quaternary period have dramatically affected the population genetic structure of many species. We reconstruct the recent demographic history of the coyote (Canis latrans) through the use of Bayesian techniques to examine the effects of Late Quaternary climatic perturbations on the genetic structure of a highly mobile generalist species. Our analysis reveals a lack of phylogeographic structure throughout the range but past population size changes correlated with climatic changes. We conclude that even generalist carnivorous species are very susceptible to environmental changes associated with climatic perturbations. This effect may be enhanced in coyotes by interspecific competition with larger carnivores. PMID:22491760

  4. A coupled phylogeographical and species distribution modelling approach recovers the demographical history of a Neotropical seasonally dry forest tree species.

    PubMed

    Collevatti, Rosane G; Terribile, Levi Carina; Lima-Ribeiro, Matheus S; Nabout, Joăo C; de Oliveira, Guilherme; Rangel, Thiago F; Rabelo, Suelen G; Diniz-Filho, Jose A F

    2012-12-01

    We investigated here the demographical history of Tabebuia impetiginosa (Bignoniaceae) to understand the dynamics of the disjunct geographical distribution of South American seasonally dry forests (SDFs), based on coupling an ensemble approach encompassing hindcasting species distribution modelling and statistical phylogeographical analysis. We sampled 17 populations (280 individuals) in central Brazil and analysed the polymorphisms at chloroplast (trnS-trnG, psbA-trnH, and ycf6-trnC intergenic spacers) and nuclear (ITS nrDNA) genomes. Phylogenetic analyses based on median-joining network showed no haplotype sharing among population but strong evidence of incomplete lineage sorting. Coalescent analyses showed historical constant populations size, negligible gene flow among populations, and an ancient time to most recent common ancestor dated from ~4.7 ± 1.1 Myr BP. Most divergences dated from the Lower Pleistocene, and no signal of important population size reduction was found in coalescent tree and tests of demographical expansion. Demographical scenarios were built based on past geographical range dynamic models, using two a priori biogeographical hypotheses ('Pleistocene Arc' and 'Amazonian SDF expansion') and on two additional hypotheses suggested by the palaeodistribution modelling built with several algorithms for distribution modelling and palaeoclimatic data. The simulation of these demographical scenarios showed that the pattern of diversity found so far for T. impetiginosa is in consonance with a palaeodistribution expansion during the last glacial maximum (LGM, 21 kyr BP), strongly suggesting that the current disjunct distribution of T. impetiginosa in SDFs may represent a climatic relict of a once more wide distribution. PMID:23094833

  5. Demographic and Morphological Perspectives on Life History Evolution and Conservation of New World Monkeys

    Microsoft Academic Search

    Gregory E. Blomquist; Martin M. Kowalewski; Steven R. Leigh

    As an order, primates are distinguished by several features of their life histories from other mammals. These include late achievement of sexual maturity, low female reproductive rates and potentially very long lives (Martin 1990). New World primates present a diverse array of life histories and social organizations (Ross 1991; Garber and Leigh 1997). In this chapter we explore primate life

  6. Effects of Mitochondrial DNA Rate Variation on Reconstruction of Pleistocene Demographic History in a Social Avian Species, Pomatostomus superciliosus

    PubMed Central

    Norman, Janette A.; Blackmore, Caroline J.; Rourke, Meaghan; Christidis, Les

    2014-01-01

    Mitochondrial sequence data is often used to reconstruct the demographic history of Pleistocene populations in an effort to understand how species have responded to past climate change events. However, departures from neutral equilibrium conditions can confound evolutionary inference in species with structured populations or those that have experienced periods of population expansion or decline. Selection can affect patterns of mitochondrial DNA variation and variable mutation rates among mitochondrial genes can compromise inferences drawn from single markers. We investigated the contribution of these factors to patterns of mitochondrial variation and estimates of time to most recent common ancestor (TMRCA) for two clades in a co-operatively breeding avian species, the white-browed babbler Pomatostomus superciliosus. Both the protein-coding ND3 gene and hypervariable domain I control region sequences showed departures from neutral expectations within the superciliosus clade, and a two-fold difference in TMRCA estimates. Bayesian phylogenetic analysis provided evidence of departure from a strict clock model of molecular evolution in domain I, leading to an over-estimation of TMRCA for the superciliosus clade at this marker. Our results suggest mitochondrial studies that attempt to reconstruct Pleistocene demographic histories should rigorously evaluate data for departures from neutral equilibrium expectations, including variation in evolutionary rates across multiple markers. Failure to do so can lead to serious errors in the estimation of evolutionary parameters and subsequent demographic inferences concerning the role of climate as a driver of evolutionary change. These effects may be especially pronounced in species with complex social structures occupying heterogeneous environments. We propose that environmentally driven differences in social structure may explain observed differences in evolutionary rate of domain I sequences, resulting from longer than expected retention times for matriarchal lineages in the superciliosus clade. PMID:25181547

  7. Estimating Density Dependence from Population Time Series Using Demographic Theory and Life?History Data

    Microsoft Academic Search

    R. Lande; S. Engen; F. Filli; E. Matthysen; H. Weimerskirch

    2002-01-01

    abstract:,For populations,with a density-dependent life history reproducing at discrete annual intervals, we analyze small or mod- erate fluctuations in population size around a stable equilibrium, which,is applicable to many,vertebrate populations. Using a life history having age at maturity a, with stochasticity and density de- pendence in adult recruitment and mortality, we derive a linearized autoregressive equation,with time lags from,1 to

  8. Demographic Structure and Evolutionary History of Drosophila ornatifrons (Diptera, Drosophilidae) from Atlantic Forest of Southern Brazil.

    PubMed

    Gustani, Emanuele C; Oliveira, Ana Paula F; Santos, Mateus H; Machado, Luciana P B; Mateus, Rogério P

    2015-04-01

    Drosoph1la ornatifrons of the guarani group (Diptera: Drosophilidae) is found mainly in humid areas of the Atlantic Forest biome, especially in the southern region of Brazil. Historical and contemporary fragmentation events influenced species diversity and distribution in this biome, although the role of paleoclimatic and paleogeographic events remain to be verified. The objective of the present study was to evaluate the demographic structure of D. ornatifrons from collection sites that are remnants of Atlantic Forest in southern Brazil, in order to contribute to the understanding of the processes that affected the patterns of genetic variability in this species. To achieve this goal, we sequenced 51 individuals from nine localities and 64 individuals from six localities for the mitochondrial genes Cytochrome Oxidase I and II, respectively. Our results indicate that D. ornatifrons may have experienced a demographic expansion event from the southernmost locations of its distribution, most likely from those located next to the coast and in fragments of Atlantic Forest inserted in the Pampa biome (South 2 group), towards the interior (South 1 group). This expansion probably started after the last glacial maximum, between 20,000 and 18,000 years ago, and was intensified near the Pleistocene-Holocene transition, around 12,000 years ago, when temperature started to rise. In this work we discuss how the haplotypes found barriers to gene flow and dispersal, influenced by the biogeographic pattern of Atlantic Forest. PMID:25826062

  9. Phylogeography and demographic history of Lacerta lepida in the Iberian Peninsula: multiple refugia, range expansions and secondary contact zones

    PubMed Central

    2011-01-01

    Background The Iberian Peninsula is recognized as an important refugial area for species survival and diversification during the climatic cycles of the Quaternary. Recent phylogeographic studies have revealed Iberia as a complex of multiple refugia. However, most of these studies have focused either on species with narrow distributions within the region or species groups that, although widely distributed, generally have a genetic structure that relates to pre-Quaternary cladogenetic events. In this study we undertake a detailed phylogeographic analysis of the lizard species, Lacerta lepida, whose distribution encompasses the entire Iberian Peninsula. We attempt to identify refugial areas, recolonization routes, zones of secondary contact and date demographic events within this species. Results Results support the existence of 6 evolutionary lineages (phylogroups) with a strong association between genetic variation and geography, suggesting a history of allopatric divergence in different refugia. Diversification within phylogroups is concordant with the onset of the Pleistocene climatic oscillations. The southern regions of several phylogroups show a high incidence of ancestral alleles in contrast with high incidence of recently derived alleles in northern regions. All phylogroups show signs of recent demographic and spatial expansions. We have further identified several zones of secondary contact, with divergent mitochondrial haplotypes occurring in narrow zones of sympatry. Conclusions The concordant patterns of spatial and demographic expansions detected within phylogroups, together with the high incidence of ancestral haplotypes in southern regions of several phylogroups, suggests a pattern of contraction of populations into southern refugia during adverse climatic conditions from which subsequent northern expansions occurred. This study supports the emergent pattern of multiple refugia within Iberia but adds to it by identifying a pattern of refugia coincident with the southern distribution limits of individual evolutionary lineages. These areas are important in terms of long-term species persistence and therefore important areas for conservation. PMID:21682856

  10. Khoisan hunter-gatherers have been the largest population throughout most of modern-human demographic history

    PubMed Central

    Kim, Hie Lim; Ratan, Aakrosh; Perry, George H.; Montenegro, Alvaro; Miller, Webb; Schuster, Stephan C.

    2014-01-01

    The Khoisan people from Southern Africa maintained ancient lifestyles as hunter-gatherers or pastoralists up to modern times, though little else is known about their early history. Here we infer early demographic histories of modern humans using whole-genome sequences of five Khoisan individuals and one Bantu speaker. Comparison with a 420?K SNP data set from worldwide individuals demonstrates that two of the Khoisan genomes from the Ju/’hoansi population contain exclusive Khoisan ancestry. Coalescent analysis shows that the Khoisan and their ancestors have been the largest populations since their split with the non-Khoisan population ~100–150?kyr ago. In contrast, the ancestors of the non-Khoisan groups, including Bantu-speakers and non-Africans, experienced population declines after the split and lost more than half of their genetic diversity. Paleoclimate records indicate that the precipitation in southern Africa increased ~80–100?kyr ago while west-central Africa became drier. We hypothesize that these climate differences might be related to the divergent-ancient histories among human populations. PMID:25471224

  11. Psychosocial Outcomes for Adult Children of Parents with Severe Mental Illnesses: Demographic and Clinical History Predictors

    ERIC Educational Resources Information Center

    Mowbray, Carol T.; Bybee, Deborah; Oyserman, Daphna; MacFarlane, Peter; Bowersox, Nicholas

    2006-01-01

    Children of parents with mental illness are at risk of psychiatric and behavioral problems. Few studies have investigated the psychosocial outcomes of these children in adulthood or the parental psychiatric history variables that predict resilience. From a sample of 379 mothers with serious mental illnesses, 157 women who had at least one adult…

  12. Museum DNA reveals the demographic history of the endangered Seychelles warbler.

    PubMed

    Spurgin, Lewis G; Wright, David J; van der Velde, Marco; Collar, Nigel J; Komdeur, Jan; Burke, Terry; Richardson, David S

    2014-11-01

    The importance of evolutionary conservation - how understanding evolutionary forces can help guide conservation decisions - is widely recognized. However, the historical demography of many endangered species is unknown, despite the fact that this can have important implications for contemporary ecological processes and for extinction risk. Here, we reconstruct the population history of the Seychelles warbler (Acrocephalus sechellensis) - an ecological model species. By the 1960s, this species was on the brink of extinction, but its previous history is unknown. We used DNA samples from contemporary and museum specimens spanning 140 years to reconstruct bottleneck history. We found a 25% reduction in genetic diversity between museum and contemporary populations, and strong genetic structure. Simulations indicate that the Seychelles warbler was bottlenecked from a large population, with an ancestral N e of several thousands falling to <50 within the last century. Such a rapid decline, due to anthropogenic factors, has important implications for extinction risk in the Seychelles warbler, and our results will inform conservation practices. Reconstructing the population history of this species also allows us to better understand patterns of genetic diversity, inbreeding and promiscuity in the contemporary populations. Our approaches can be applied across species to test ecological hypotheses and inform conservation. PMID:25553073

  13. Museum DNA reveals the demographic history of the endangered Seychelles warbler

    PubMed Central

    Spurgin, Lewis G; Wright, David J; van der Velde, Marco; Collar, Nigel J; Komdeur, Jan; Burke, Terry; Richardson, David S

    2014-01-01

    The importance of evolutionary conservation – how understanding evolutionary forces can help guide conservation decisions – is widely recognized. However, the historical demography of many endangered species is unknown, despite the fact that this can have important implications for contemporary ecological processes and for extinction risk. Here, we reconstruct the population history of the Seychelles warbler (Acrocephalus sechellensis) – an ecological model species. By the 1960s, this species was on the brink of extinction, but its previous history is unknown. We used DNA samples from contemporary and museum specimens spanning 140 years to reconstruct bottleneck history. We found a 25% reduction in genetic diversity between museum and contemporary populations, and strong genetic structure. Simulations indicate that the Seychelles warbler was bottlenecked from a large population, with an ancestral Ne of several thousands falling to <50 within the last century. Such a rapid decline, due to anthropogenic factors, has important implications for extinction risk in the Seychelles warbler, and our results will inform conservation practices. Reconstructing the population history of this species also allows us to better understand patterns of genetic diversity, inbreeding and promiscuity in the contemporary populations. Our approaches can be applied across species to test ecological hypotheses and inform conservation. PMID:25553073

  14. Relationships among and between ELL Status, Demographic Characteristics, Enrollment History, and School Persistence. CRESST Report 810

    ERIC Educational Resources Information Center

    Kim, Jinok

    2011-01-01

    This report examines enrollment history, achievement gaps, and persistence in school for ELL students and reclassified ELL students as compared to non-ELL students. The study uses statewide individual-level data sets merged from students' entry to exit in the state's public school system for graduate cohorts of 2006, 2007, and 2008. Analytic…

  15. Life History and Demographic Variation in the California Tiger Salamander ( Ambystoma californiense )

    Microsoft Academic Search

    Peter C. Trenham; H. Bradley Shaffer; Walter D. Koenig; Mark R. Stromberg; S. T. Ross

    2000-01-01

    In December 1991, we initiated a long-term study of the California Tiger Sala- mander (Ambystoma californiense) at a breeding pond in Monterey County, California. Because of habitat loss, this species is a candidate for federal endangered species status, but many basic features of its life history and demography have not been studied in detail. During the first seven years of

  16. Population structure and demographic history of Sicyopterus japonicus (Perciformes; Gobiidae) in Taiwan inferred from mitochondrial control region sequences.

    PubMed

    Ju, Y M; Hsu, C H; Fang, L S; Lin, H D; Wu, J H; Han, C C; Chen, I-S; Chiang, T Y

    2013-01-01

    The amphidromous goby Sicyopterus japonicus is distributed throughout southern Taiwan and Japan. Larvae of this freshwater fish go through a long marine stage. This migratory mode influences population genetic structure. We examined the genetic diversity, population differentiation, and demographic history of S. japonicus based on the mitochondrial DNA control region. We identified 102 haplotypes from 107 S. japonicus individuals from 22 populations collected from Taiwan and Islet Lanyu. High mean haplotype diversity (h = 0.999) versus low nucleotide diversity (?? = 0.008) was detected across populations. There was low correspondence between clusters identified in the neighbor-joining tree and geographical region, as also indicated by AMOVA and pairwise F(ST) estimates. Both mismatch distribution analysis and Tajima's D test indicated that S. japonicus likely experienced a demographic expansion. Using a Bayesian skyline plot approach, we estimated the time of onset of the expansion of S. japonicus at 135 kyr (during the Pleistocene) and the time of stable effective population size at approximately 2.5 kyr (last glacial maximum). Based on these results, we suggest 1) a panmictic population at the oceanic planktonic larval stage, mediated by the Kuroshio current; 2) a long planktonic marine stage and long period of dispersal, which may have permitted efficient tracking of environmental shifts during the Pleistocene; and 3) a stable, constant population size ever since the last glacial maximum. PMID:24089094

  17. Life history and demographic drivers of reservoir competence for three tick-borne zoonotic pathogens.

    PubMed

    Ostfeld, Richard S; Levi, Taal; Jolles, Anna E; Martin, Lynn B; Hosseini, Parviez R; Keesing, Felicia

    2014-01-01

    Animal and plant species differ dramatically in their quality as hosts for multi-host pathogens, but the causes of this variation are poorly understood. A group of small mammals, including small rodents and shrews, are among the most competent natural reservoirs for three tick-borne zoonotic pathogens, Borrelia burgdorferi, Babesia microti, and Anaplasma phagocytophilum, in eastern North America. For a group of nine commonly-infected mammals spanning >2 orders of magnitude in body mass, we asked whether life history features or surrogates for (unknown) encounter rates with ticks, predicted reservoir competence for each pathogen. Life history features associated with a fast pace of life generally were positively correlated with reservoir competence. However, a model comparison approach revealed that host population density, as a proxy for encounter rates between hosts and pathogens, generally received more support than did life history features. The specific life history features and the importance of host population density differed somewhat between the different pathogens. We interpret these results as supporting two alternative but non-exclusive hypotheses for why ecologically widespread, synanthropic species are often the most competent reservoirs for multi-host pathogens. First, multi-host pathogens might adapt to those hosts they are most likely to experience, which are likely to be the most abundant and/or frequently bitten by tick vectors. Second, species with fast life histories might allocate less to certain immune defenses, which could increase their reservoir competence. Results suggest that of the host species that might potentially be exposed, those with comparatively high population densities, small bodies, and fast pace of life will often be keystone reservoirs that should be targeted for surveillance or management. PMID:25232722

  18. Life History and Demographic Drivers of Reservoir Competence for Three Tick-Borne Zoonotic Pathogens

    PubMed Central

    Ostfeld, Richard S.; Levi, Taal; Jolles, Anna E.; Martin, Lynn B.; Hosseini, Parviez R.; Keesing, Felicia

    2014-01-01

    Animal and plant species differ dramatically in their quality as hosts for multi-host pathogens, but the causes of this variation are poorly understood. A group of small mammals, including small rodents and shrews, are among the most competent natural reservoirs for three tick-borne zoonotic pathogens, Borrelia burgdorferi, Babesia microti, and Anaplasma phagocytophilum, in eastern North America. For a group of nine commonly-infected mammals spanning >2 orders of magnitude in body mass, we asked whether life history features or surrogates for (unknown) encounter rates with ticks, predicted reservoir competence for each pathogen. Life history features associated with a fast pace of life generally were positively correlated with reservoir competence. However, a model comparison approach revealed that host population density, as a proxy for encounter rates between hosts and pathogens, generally received more support than did life history features. The specific life history features and the importance of host population density differed somewhat between the different pathogens. We interpret these results as supporting two alternative but non-exclusive hypotheses for why ecologically widespread, synanthropic species are often the most competent reservoirs for multi-host pathogens. First, multi-host pathogens might adapt to those hosts they are most likely to experience, which are likely to be the most abundant and/or frequently bitten by tick vectors. Second, species with fast life histories might allocate less to certain immune defenses, which could increase their reservoir competence. Results suggest that of the host species that might potentially be exposed, those with comparatively high population densities, small bodies, and fast pace of life will often be keystone reservoirs that should be targeted for surveillance or management. PMID:25232722

  19. Demographic history, marker variability and genetic differentiation in sandy beach fauna: What is the meaning of low FST's?

    NASA Astrophysics Data System (ADS)

    Bezuidenhout, Karien; Nel, Ronel; Hauser, Lorenz

    2014-10-01

    This note demonstrates the effect of locus variability and demographic history on the estimation of genetic differentiation and its interpretation in terms of ecological connectivity. Cytochrome c oxidase subunit I (COI, mtDNA) sequences of the beach clam Donax serra from four sites along the South African coast were analysed. D. serra showed low COI haplotype diversity (h = 0.30 ± 0.069, 7 haplotypes), suggesting expansion from a small source population into extant habitats. As a consequence, statistical power to measure genetic connectivity was low. The lack of genetic population structure therefore does not necessarily demonstrate high connectivity. Although COI has been used successfully to identify species and populations isolated for prolonged periods of time, lack of differentiation has to be interpreted with caution, especially in terms of extant patterns of connectivity.

  20. Genetic diversity, genetic structure and demographic history of Cycas simplicipinna (Cycadaceae) assessed by DNA sequences and SSR markers

    PubMed Central

    2014-01-01

    Background Cycas simplicipinna (T. Smitinand) K. Hill. (Cycadaceae) is an endangered species in China. There were seven populations and 118 individuals that we could collect were genotyped in this study. Here, we assessed the genetic diversity, genetic structure and demographic history of this species. Results Analyses of data of DNA sequences (two maternally inherited intergenic spacers of chloroplast, cpDNA and one biparentally inherited internal transcribed spacer region ITS4-ITS5, nrDNA) and sixteen microsatellite loci (SSR) were conducted in the species. Of the 118 samples, 86 individuals from the seven populations were used for DNA sequencing and 115 individuals from six populations were used for the microsatellite study. We found high genetic diversity at the species level, low genetic diversity within each of the seven populations and high genetic differentiation among the populations. There was a clear genetic structure within populations of C. simplicipinna. A demographic history inferred from DNA sequencing data indicates that C. simplicipinna experienced a recent population contraction without retreating to a common refugium during the last glacial period. The results derived from SSR data also showed that C. simplicipinna underwent past effective population contraction, likely during the Pleistocene. Conclusions Some genetic features of C. simplicipinna such as having high genetic differentiation among the populations, a clear genetic structure and a recent population contraction could provide guidelines for protecting this endangered species from extinction. Furthermore, the genetic features with population dynamics of the species in our study would help provide insights and guidelines for protecting other endangered species effectively. PMID:25016306

  1. Blacktip reef sharks, Carcharhinus melanopterus, have high genetic structure and varying demographic histories in their Indo-Pacific range.

    PubMed

    Vignaud, Thomas M; Mourier, Johann; Maynard, Jeffrey A; Leblois, Raphael; Spaet, Julia; Clua, Eric; Neglia, Valentina; Planes, Serge

    2014-11-01

    For free-swimming marine species like sharks, only population genetics and demographic history analyses can be used to assess population health/status as baseline population numbers are usually unknown. We investigated the population genetics of blacktip reef sharks, Carcharhinus melanopterus; one of the most abundant reef-associated sharks and the apex predator of many shallow water reefs of the Indian and Pacific Oceans. Our sampling includes 4 widely separated locations in the Indo-Pacific and 11 islands in French Polynesia with different levels of coastal development. Four-teen microsatellite loci were analysed for samples from all locations and two mitochondrial DNA fragments, the control region and cytochrome b, were examined for 10 locations. For microsatellites, genetic diversity is higher for the locations in the large open systems of the Red Sea and Australia than for the fragmented habitat of the smaller islands of French Polynesia. Strong significant structure was found for distant locations with FST values as high as ~0.3, and a smaller but still significant structure is found within French Polynesia. Both mitochondrial genes show only a few mutations across the sequences with a dominant shared haplotype in French Polynesia and New Caledonia suggesting a common lineage different to that of East Australia. Demographic history analyses indicate population expansions in the Red Sea and Australia that may coincide with sea level changes after climatic events. Expansions and flat signals are indicated for French Polynesia as well as a significant recent bottleneck for Moorea, the most human-impacted lagoon of the locations in French Polynesia. PMID:25251515

  2. Demographic and clinical factors associated with radiographic severity of first metatarsophalangeal joint osteoarthritis: cross-sectional findings from the Clinical Assessment Study of the Foot

    PubMed Central

    Menz, H.B.; Roddy, E.; Marshall, M.; Thomas, M.J.; Rathod, T.; Myers, H.; Thomas, E.; Peat, G.M.

    2015-01-01

    Summary Objective To explore demographic and clinical factors associated with radiographic severity of first metatarsophalangeal joint osteoarthritis (OA) (First MTPJ OA). Design Adults aged ?50 years registered with four general practices were mailed a Health Survey. Responders reporting foot pain within the last 12 months were invited to undergo a clinical assessment and weight-bearing dorso-plantar and lateral radiographs of both feet. Radiographic first MTPJ OA in the most severely affected foot was graded into four categories using a validated atlas. Differences in selected demographic and clinical factors were explored across the four radiographic severity subgroups using analysis of variance (ANOVA) and ordinal regression. Results Clinical and radiographic data were available from 517 participants, categorised as having no (n = 105), mild (n = 228), moderate (n = 122) or severe (n = 62) first MTPJ OA. Increased radiographic severity was associated with older age and lower educational attainment. After adjusting for age, increased radiographic first MTPJ OA severity was significantly associated with an increased prevalence of dorsal hallux and first MTPJ pain, hallux valgus, first interphalangeal joint (IPJ) hyperextension, keratotic lesions on the dorsal aspect of the hallux and first MTPJ, decreased first MTPJ dorsiflexion, ankle/subtalar joint eversion and ankle joint dorsiflexion range of motion, and a trend towards a more pronated foot posture. Conclusions This cross-sectional study has identified several dose–response associations between radiographic severity of first MTPJ OA and a range of demographic and clinical factors. These findings highlight the progressive nature of first MTPJ OA and provide insights into the spectrum of presentation of the condition in clinical practice. PMID:25450852

  3. Genetic structuring and recent demographic history of red pandas (Ailurus fulgens) inferred from microsatellite and mitochondrial DNA.

    PubMed

    Hu, Yibo; Guo, Yu; Qi, Dunwu; Zhan, Xiangjiang; Wu, Hua; Bruford, Michael W; Wei, Fuwen

    2011-07-01

    Clarification of the genetic structure and population history of a species can shed light on the impacts of landscapes, historical climate change and contemporary human activities and thus enables evidence-based conservation decisions for endangered organisms. The red panda (Ailurus fulgens) is an endangered species distributing at the edge of the Qinghai-Tibetan Plateau and is currently subject to habitat loss, fragmentation and population decline, thus representing a good model to test the influences of the above-mentioned factors on a plateau edge species. We combined nine microsatellite loci and 551?bp of mitochondrial control region (mtDNA CR) to explore the genetic structure and demographic history of this species. A total of 123 individuals were sampled from 23 locations across five populations. High levels of genetic variation were identified for both mtDNA and microsatellites. Phylogeographic analyses indicated little geographic structure, suggesting historically wide gene flow. However, microsatellite-based Bayesian clustering clearly identified three groups (Qionglai-Liangshan, Xiaoxiangling and Gaoligong-Tibet). A significant isolation-by-distance pattern was detected only after removing Xiaoxiangling. For mtDNA data, there was no statistical support for a historical population expansion or contraction for the whole sample or any population except Xiaoxiangling where a signal of contraction was detected. However, Bayesian simulations of population history using microsatellite data did pinpoint population declines for Qionglai, Xiaoxiangling and Gaoligong, demonstrating significant influences of human activity on demography. The unique history of the Xiaoxiangling population plays a critical role in shaping the genetic structure of this species, and large-scale habitat loss and fragmentation is hampering gene flow among populations. The implications of our findings for the biogeography of the Qinghai-Tibetan Plateau, subspecies classification and conservation of red pandas are discussed. PMID:21585580

  4. AFRICAN GENETIC DIVERSITY: Implications for Human Demographic History, Modern Human Origins, and Complex Disease Mapping

    PubMed Central

    Campbell, Michael C.; Tishkoff, Sarah A.

    2010-01-01

    Comparative studies of ethnically diverse human populations, particularly in Africa, are important for reconstructing human evolutionary history and for understanding the genetic basis of phenotypic adaptation and complex disease. African populations are characterized by greater levels of genetic diversity, extensive population substructure, and less linkage disequilibrium (LD) among loci compared to non-African populations. Africans also possess a number of genetic adaptations that have evolved in response to diverse climates and diets, as well as exposure to infectious disease. This review summarizes patterns and the evolutionary origins of genetic diversity present in African populations, as well as their implications for the mapping of complex traits, including disease susceptibility. PMID:18593304

  5. A history of osteomyelitis from the Journal of Bone and Joint Surgery: 1948 TO 2006.

    PubMed

    Klenerman, L

    2007-05-01

    Osteomyelitis is one of the oldest diseases known. It took many years before the acute infection could be brought under control with antibiotics and chronic osteomyelitis remains difficult to manage. The modern history of the disease is reflected in the pages of the Journal of Bone and Joint Surgery. PMID:17540756

  6. Population Genomic Analysis Reveals a Rich Speciation and Demographic History of Orang-utans (Pongo pygmaeus and Pongo abelii)

    PubMed Central

    Ma, Xin; Kelley, Joanna L.; Eilertson, Kirsten; Musharoff, Shaila; Degenhardt, Jeremiah D.; Martins, André L.; Vinar, Tomas; Kosiol, Carolin; Siepel, Adam; Gutenkunst, Ryan N.; Bustamante, Carlos D.

    2013-01-01

    To gain insights into evolutionary forces that have shaped the history of Bornean and Sumatran populations of orang-utans, we compare patterns of variation across more than 11 million single nucleotide polymorphisms found by previous mitochondrial and autosomal genome sequencing of 10 wild-caught orang-utans. Our analysis of the mitochondrial data yields a far more ancient split time between the two populations (?3.4 million years ago) than estimates based on autosomal data (0.4 million years ago), suggesting a complex speciation process with moderate levels of primarily male migration. We find that the distribution of selection coefficients consistent with the observed frequency spectrum of autosomal non-synonymous polymorphisms in orang-utans is similar to the distribution in humans. Our analysis indicates that 35% of genes have evolved under detectable negative selection. Overall, our findings suggest that purifying natural selection, genetic drift, and a complex demographic history are the dominant drivers of genome evolution for the two orang-utan populations. PMID:24194868

  7. Comparative phylogeography and demographic history of European shads (Alosa alosa and A. fallax) inferred from mitochondrial DNA

    PubMed Central

    2012-01-01

    Background Comparative broad-scale phylogeographic studies of aquatic organisms provide insights on biotic responses to the paleohydrological dynamics associated with climatic oscillations. These insights can be used to formulate a framework for understanding the evolutionary history of a species or closely related taxa as well as aid in predictive modeling of further responses to climate change. Anadromous fishes constitute interesting models for understanding the relative importance of environmental versus biological factors in shaping intraspecific genetic substructure on the interface between marine and freshwater realms. European shads, Alosa alosa and A. fallax are anadromous species that have persisted through historical large-scale environmental perturbations and now additionally face an array of anthropogenic challenges. A comprehensive phylogeographic investigation of these species is needed to provide insights on both the historical processes that have shaped their extant genetic structure and diversity, and the prospects for their future management and conservation. Results Despite introgressive hybridization, A. alosa and A. fallax are genetically divergent, congruent with previous studies. Three similarly divergent mtDNA clades were recognized within both A. fallax and A. alosa, most likely originating during common periods of isolation during the Pleistocene among the studied oceanographic regions. Periods of basin isolation apparently extended to the Black Sea as additional Alosa clades occur there. The present day geographic distribution of genetic diversity within European Alosa sp. suggests the existence of a strong but permeable barrier between the Atlantic and Mediterranean seas, as shown for a number of other aquatic species. Overall mtDNA diversity is considerably lower for A. alosa compared to A. fallax, suggesting that the former species is more sensitive to climatic as well as anthropogenic changes. For A. fallax, migration from the Mediterranean to the Atlantic was detected but not in the opposite direction, with colonization of the North Atlantic probably occurring after last glacial maximum. Conclusion The similar haplotype network topologies between the two species support a common intraspecific history of isolation. Despite these similarities, A. alosa and A. fallax have clearly responded differently to the hydrological dynamics of the Pleistocene, as reflected in their distinct demographic histories. As the species additionally occupy different ecological niches it should not be surprising that they differ in resilience to natural or human-mediated climatic changes. For A. fallax, it is further clear that its demographic response to large-scale hydrological events is not synchronized between the Atlantic and Mediterranean basins. These regional and species-specific differences should be incorporated into future predictive modeling of biological response to climate change as well as current management concepts. PMID:23020523

  8. Inference of Gorilla Demographic and Selective History from Whole-Genome Sequence Data

    PubMed Central

    McManus, Kimberly F.; Kelley, Joanna L.; Song, Shiya; Veeramah, Krishna R.; Woerner, August E.; Stevison, Laurie S.; Ryder, Oliver A.; Ape Genome Project, Great; Kidd, Jeffrey M.; Wall, Jeffrey D.; Bustamante, Carlos D.; Hammer, Michael F.

    2015-01-01

    Although population-level genomic sequence data have been gathered extensively for humans, similar data from our closest living relatives are just beginning to emerge. Examination of genomic variation within great apes offers many opportunities to increase our understanding of the forces that have differentially shaped the evolutionary history of hominid taxa. Here, we expand upon the work of the Great Ape Genome Project by analyzing medium to high coverage whole-genome sequences from 14 western lowland gorillas (Gorilla gorilla gorilla), 2 eastern lowland gorillas (G. beringei graueri), and a single Cross River individual (G. gorilla diehli). We infer that the ancestors of western and eastern lowland gorillas diverged from a common ancestor approximately 261 ka, and that the ancestors of the Cross River population diverged from the western lowland gorilla lineage approximately 68 ka. Using a diffusion approximation approach to model the genome-wide site frequency spectrum, we infer a history of western lowland gorillas that includes an ancestral population expansion of 1.4-fold around 970 ka and a recent 5.6-fold contraction in population size 23 ka. The latter may correspond to a major reduction in African equatorial forests around the Last Glacial Maximum. We also analyze patterns of variation among western lowland gorillas to identify several genomic regions with strong signatures of recent selective sweeps. We find that processes related to taste, pancreatic and saliva secretion, sodium ion transmembrane transport, and cardiac muscle function are overrepresented in genomic regions predicted to have experienced recent positive selection. PMID:25534031

  9. Nautilus pompilius life history and demographics at the Osprey Reef Seamount, Coral Sea, Australia.

    PubMed

    Dunstan, Andrew J; Ward, Peter D; Marshall, N Justin

    2011-01-01

    Nautiloids are the subject of speculation as to their threatened status arising from the impacts of targeted fishing for the ornamental shell market. Life history knowledge is essential to understand the susceptibility of this group to overfishing and to the instigation of management frameworks. This study provides a comprehensive insight into the life of Nautilus in the wild. At Osprey Reef from 1998-2008, trapping for Nautilus was conducted on 354 occasions, with 2460 individuals of one species, Nautilus pompilius, captured and 247 individuals recaptured. Baited remote underwater video systems (BRUVS) were deployed on 15 occasions and six remotely operated vehicle (ROV) dives from 100-800 m were conducted to record Nautilus presence and behavior. Maturity, sex and size data were recorded, while measurements of recaptured individuals allowed estimation of growth rates to maturity, and longevity beyond maturity. We found sexual dimorphism in size at maturity (males: 131.9±SD?=?2.6 mm; females: 118.9±7.5 mm shell diameter) in a population dominated by mature individuals (58%). Mean growth rates of 15 immature recaptured animals were 0.061±0.023 mm day(-1) resulting in an estimate of around 15.5 years to maturation. Recaptures of mature animals after five years provide evidence of a lifespan exceeding 20 years. Juvenile Nautilus pompilius feeding behavior was recorded for the first time within the same depth range (200-610 m) as adults. Our results provide strong evidence of a K-selected life history for Nautilus from a detailed study of a 'closed' wild population. In conjunction with population size and density estimates established for the Osprey Reef Nautilus, this work allows calculations for sustainable catch and provides mechanisms to extrapolate these findings to other extant nautiloid populations (Nautilus and Allonautilus spp.) throughout the Indo-Pacific. PMID:21347356

  10. Nautilus pompilius Life History and Demographics at the Osprey Reef Seamount, Coral Sea, Australia

    PubMed Central

    Dunstan, Andrew J.; Ward, Peter D.; Marshall, N. Justin

    2011-01-01

    Nautiloids are the subject of speculation as to their threatened status arising from the impacts of targeted fishing for the ornamental shell market. Life history knowledge is essential to understand the susceptibility of this group to overfishing and to the instigation of management frameworks. This study provides a comprehensive insight into the life of Nautilus in the wild. At Osprey Reef from 1998–2008, trapping for Nautilus was conducted on 354 occasions, with 2460 individuals of one species, Nautilus pompilius, captured and 247 individuals recaptured. Baited remote underwater video systems (BRUVS) were deployed on 15 occasions and six remotely operated vehicle (ROV) dives from 100–800 m were conducted to record Nautilus presence and behavior. Maturity, sex and size data were recorded, while measurements of recaptured individuals allowed estimation of growth rates to maturity, and longevity beyond maturity. We found sexual dimorphism in size at maturity (males: 131.9±SD?=?2.6 mm; females: 118.9±7.5 mm shell diameter) in a population dominated by mature individuals (58%). Mean growth rates of 15 immature recaptured animals were 0.061±0.023 mm day?1 resulting in an estimate of around 15.5 years to maturation. Recaptures of mature animals after five years provide evidence of a lifespan exceeding 20 years. Juvenile Nautilus pompilius feeding behavior was recorded for the first time within the same depth range (200–610 m) as adults. Our results provide strong evidence of a K-selected life history for Nautilus from a detailed study of a ‘closed’ wild population. In conjunction with population size and density estimates established for the Osprey Reef Nautilus, this work allows calculations for sustainable catch and provides mechanisms to extrapolate these findings to other extant nautiloid populations (Nautilus and Allonautilus spp.) throughout the Indo-Pacific. PMID:21347356

  11. Inference of gorilla demographic and selective history from whole-genome sequence data.

    PubMed

    McManus, Kimberly F; Kelley, Joanna L; Song, Shiya; Veeramah, Krishna R; Woerner, August E; Stevison, Laurie S; Ryder, Oliver A; Ape Genome Project, Great; Kidd, Jeffrey M; Wall, Jeffrey D; Bustamante, Carlos D; Hammer, Michael F

    2015-03-01

    Although population-level genomic sequence data have been gathered extensively for humans, similar data from our closest living relatives are just beginning to emerge. Examination of genomic variation within great apes offers many opportunities to increase our understanding of the forces that have differentially shaped the evolutionary history of hominid taxa. Here, we expand upon the work of the Great Ape Genome Project by analyzing medium to high coverage whole-genome sequences from 14 western lowland gorillas (Gorilla gorilla gorilla), 2 eastern lowland gorillas (G. beringei graueri), and a single Cross River individual (G. gorilla diehli). We infer that the ancestors of western and eastern lowland gorillas diverged from a common ancestor approximately 261 ka, and that the ancestors of the Cross River population diverged from the western lowland gorilla lineage approximately 68 ka. Using a diffusion approximation approach to model the genome-wide site frequency spectrum, we infer a history of western lowland gorillas that includes an ancestral population expansion of 1.4-fold around 970 ka and a recent 5.6-fold contraction in population size 23 ka. The latter may correspond to a major reduction in African equatorial forests around the Last Glacial Maximum. We also analyze patterns of variation among western lowland gorillas to identify several genomic regions with strong signatures of recent selective sweeps. We find that processes related to taste, pancreatic and saliva secretion, sodium ion transmembrane transport, and cardiac muscle function are overrepresented in genomic regions predicted to have experienced recent positive selection. PMID:25534031

  12. A brief history of the changing occupations and demographics of coleopterists from the 18th through the 20th century.

    PubMed

    Elias, Scott A

    2014-01-01

    Systematic entomology flourished as a branch of Natural History from the 1750s to the end of the nineteenth century. During this interval, the "era of Heroic Entomology," the majority of workers in the field were dedicated amateurs. This article traces the demographic and occupational shifts in entomology through this 150-year interval and into the early twentieth century. The survey is based on entomologists who studied beetles (Coleoptera), and who named sufficient numbers of species to have their own names abbreviated by subsequent taxonomists. In the eighteenth century, 27 entomologists achieved this level of prominence, of whom 37% were academics, 19% were doctors, 11% had private incomes, 19% were clergymen, and 8% were government officials. Many of those with private incomes were members of the European aristocracy, and all but one were European men. The nineteenth century list included 192 entomologists, of whom 17% were academics, 16% were museum curators, 2% were school teachers, 15% were doctors, 6% were military men, 7% were merchants, 2% were government entomologists, 6% had private incomes, 5% were clergymen, 5% were government officials, and 4% were lawyers. The demographics of entomology shifted dramatically in the nineteenth century. Whereas many of the noteworthy entomologists of the eighteenth century were German, Swedish, or French, in the nineteenth century, many more European countries are represented, and almost one-fifth of the noteworthy entomologists were from the United States. The nineteenth century list, like the eighteenth century list, contains no women. By the twentieth century, 63% of 178 noteworthy systematic entomologists were paid professionals, teaching entomology courses in universities, or studying insect taxonomy in museums and government-sponsored laboratories. Only one person on the twentieth century list had a private income, but women (ten individuals) were included on the list for the first time. PMID:23928824

  13. Genetic variation and demographic history of the Haplochromis laparogramma group of Lake Victoria--An analysis based on SINEs and mitochondrial DNA

    E-print Network

    Genetic variation and demographic history of the Haplochromis laparogramma group of Lake Victoria More than 500 endemic haplochromine cichlid species inhabit Lake Victoria. This striking species and population structure of closely related Lake Victoria cichlids and in showing the importance of applying

  14. Differential population structuring and demographic history of two closely related fish species, Japanese sea bass ( Lateolabrax japonicus) and spotted sea bass ( Lateolabrax maculatus) in Northwestern Pacific

    Microsoft Academic Search

    Jin-Xian Liu; Tian-Xiang Gao; Koji Yokogawa; Ya-Ping Zhang

    2006-01-01

    The Quaternary cold periods in the Northwestern Pacific are thought to have heavily influenced the amount and distribution of intraspecific genetic variation in marine fishes. To estimate the demographic history and genetic structure of Lateolabrax maculatus and L. japonicus in the Northwestern Pacific, 256 individuals were sampled from 19 localities throughout the distribution range of the two species. Mitochondrial DNA

  15. Contrasting recombination patterns and demographic histories of the plant pathogen Ralstonia solanacearum inferred from MLSA

    PubMed Central

    Wicker, Emmanuel; Lefeuvre, Pierre; de Cambiaire, Jean-Charles; Lemaire, Christophe; Poussier, Stéphane; Prior, Philippe

    2012-01-01

    We used multilocus sequence analysis (MLSA) on a worldwide collection of the plant pathogenic Ralstonia solanacearum (Betaproteobacteria) to retrace its complex evolutionary history. Using genetic imprints left during R. solanacearum evolution, we were able to delineate distinct evolutionary complex displaying contrasting dynamics. Among the phylotypes already described (I, IIA, IIB, III, IV), eight groups of strains with distinct evolutionary patterns, named clades, were identified. From our recombination analysis, we identified 21 recombination events that occurred within and across these lineages. Although appearing the most divergent and ancestral phylotype, phylotype IV was inferred as a gene donor for the majority of the recombination events that we detected. Whereas this phylotype apparently fuelled the species diversity, ongoing diversification was mainly detected within phylotype I, IIA and III. These three groups presented a recent expanding population structure, a high level of homologous recombination and evidences of long-distance migrations. Factors such as adaptation to a specific host or intense trading of infected crops may have promoted this diversification. Whether R. solanacearum lineages will eventually evolve in distinct species remains an open question. The intensification of cropping and increase of geographical dispersion may favour situations of phylotype sympatry and promote higher exchange of key factors for host adaptation from their common genetic pool. PMID:22094345

  16. Demographic history, genetic structure and gene flow in a steppe-associated raptor species

    PubMed Central

    2011-01-01

    Background Environmental preferences and past climatic changes may determine the length of time during which a species range has contracted or expanded from refugia, thereby influencing levels of genetic diversification. Connectivity among populations of steppe-associated taxa might have been maximal during the long glacial periods, and interrupted only during the shorter interglacial phases, potentially resulting in low levels of genetic differentiation among populations. We investigated this hypothesis by exploring patterns of genetic diversity, past demography and gene flow in a raptor species characteristic of steppes, the Montagu's harrier (Circus pygargus), using mitochondrial DNA data from 13 breeding populations and two wintering populations. Results Consistent with our hypothesis, Montagu's harrier has relatively low genetic variation at the mitochondrial DNA. The highest levels of genetic diversity were found in coastal Spain, France and central Asia. These areas, which were open landscapes during the Holocene, may have acted as refugia when most of the European continent was covered by forests. We found significant genetic differentiation between two population groups, at the SW and NE parts of the species' range. Two events of past population growth were detected, and occurred ca. 7500-5500 and ca. 3500-1000 years BP in the SW and NE part of the range respectively. These events were likely associated with vegetation shifts caused by climate and human-induced changes during the Holocene. Conclusions The relative genetic homogeneity observed across populations of this steppe raptor may be explained by a short isolation time, relatively recent population expansions and a relaxed philopatry. We highlight the importance of considering the consequence of isolation and colonization processes in order to better understand the evolutionary history of steppe species. PMID:22093489

  17. Concordant phylogeographies of 2 malaria vectors attest to common spatial and demographic histories.

    PubMed

    Pedro, Pedro M; Uezu, Alexandre; Sallum, Maria Anice Mureb

    2010-01-01

    The phylogeography of South American lineages is a topic of heated debate. Although a single process is unlikely to describe entire ecosystems, related species, which incur similar habitat limitations, can inform the history for a subsection of assemblages. We compared the phylogeographic patterns of the cytochrome oxidase I marker from Anopheles triannulatus (N = 72) and previous results for A. darlingi (N = 126) in a broad portion of their South American distributions. Both species share similar population subdivisions, with aggregations northeast of the Amazon River, in southern coastal Brazil and 2 regions in central Brazil. The average capital EF, Cyrillic(ST) between these groups was 0.39 for A. triannulatus. Populations northeast of the Amazon and in southeastern Brazil are generally reciprocally monophyletic to the remaining groups. Based on these initial analyses, we constructed the a priori hypothesis that the Amazon and regions of high declivity pose geographic barriers to dispersal in these taxa. Mantel tests confirmed that these areas block gene flow for more than 1000 km for both species. The efficacy of these impediments was tested using landscape genetics, which could not reject our a priori hypothesis but did reject simpler scenarios. Results form summary statistics and phylogenetics suggest that both lineages originated in central Amazonia (south of the Amazon River) during the late Pleistocene (579 000 years ago) and that they followed the same paths of expansion into their contemporary distributions. These results may have implications for other species sharing similar ecological limitations but probably are not applicable as a general paradigm of Neotropical biogeography. PMID:20511380

  18. Reconciling Deep Calibration and Demographic History: Bayesian Inference of Post Glacial Colonization Patterns in Carcinus aestuarii (Nardo, 1847) and C. maenas (Linnaeus, 1758)

    PubMed Central

    Marino, Ilaria A. M.; Pujolar, Jose Martin; Zane, Lorenzo

    2011-01-01

    A precise inference of past demographic histories including dating of demographic events using Bayesian methods can only be achieved with the use of appropriate molecular rates and evolutionary models. Using a set of 596 mitochondrial cytochrome c oxidase I (COI) sequences of two sister species of European green crabs of the genus Carcinus (C. maenas and C. aestuarii), our study shows how chronologies of past evolutionary events change significantly with the application of revised molecular rates that incorporate biogeographic events for calibration and appropriate demographic priors. A clear signal of demographic expansion was found for both species, dated between 10,000 and 20,000 years ago, which places the expansions events in a time frame following the Last Glacial Maximum (LGM). In the case of C. aestuarii, a population expansion was only inferred for the Adriatic-Ionian, suggestive of a colonization event following the flooding of the Adriatic Sea (18,000 years ago). For C. maenas, the demographic expansion inferred for the continental populations of West and North Europe might result from a northward recolonization from a southern refugium when the ice sheet retreated after the LGM. Collectively, our results highlight the importance of using adequate calibrations and demographic priors in order to avoid considerable overestimates of evolutionary time scales. PMID:22164307

  19. Recent Demographic History and Present Fine-Scale Structure in the Northwest Atlantic Leatherback (Dermochelys coriacea) Turtle Population

    PubMed Central

    Molfetti, Érica; Torres Vilaça, Sibelle; Georges, Jean-Yves; Plot, Virginie; Delcroix, Eric; Le Scao, Rozen; Lavergne, Anne; Barrioz, Sébastien; dos Santos, Fabrício Rodrigues; de Thoisy, Benoît

    2013-01-01

    The leatherback turtle Dermochelys coriacea is the most widely distributed sea turtle species in the world. It exhibits complex life traits: female homing and migration, migrations of juveniles and males that remain poorly known, and a strong climatic influence on resources, breeding success and sex-ratio. It is consequently challenging to understand population dynamics. Leatherbacks are critically endangered, yet the group from the Northwest Atlantic is currently considered to be under lower risk than other populations while hosting some of the largest rookeries. Here, we investigated the genetic diversity and the demographic history of contrasted rookeries from this group, namely two large nesting populations in French Guiana, and a smaller one in the French West Indies. We used 10 microsatellite loci, of which four are newly isolated, and mitochondrial DNA sequences of the control region and cytochrome b. Both mitochondrial and nuclear markers revealed that the Northwest Atlantic stock of leatherbacks derives from a single ancestral origin, but show current genetic structuration at the scale of nesting sites, with the maintenance of migrants amongst rookeries. Low nuclear genetic diversities are related to founder effects that followed consequent bottlenecks during the late Pleistocene/Holocene. Most probably in response to climatic oscillations, with a possible influence of early human hunting, female effective population sizes collapsed from 2 million to 200. Evidence of founder effects and high numbers of migrants make it possible to reconsider the population dynamics of the species, formerly considered as a metapopulation model: we propose a more relaxed island model, which we expect to be a key element in the currently observed recovering of populations. Although these Northwest Atlantic rookeries should be considered as a single evolutionary unit, we stress that local conservation efforts remain necessary since each nesting site hosts part of the genetic diversity and species history. PMID:23516429

  20. Recent demographic history and present fine-scale structure in the Northwest Atlantic leatherback (Dermochelys coriacea) turtle population.

    PubMed

    Molfetti, Erica; Vilaça, Sibelle Torres; Georges, Jean-Yves; Plot, Virginie; Delcroix, Eric; Le Scao, Rozen; Lavergne, Anne; Barrioz, Sébastien; dos Santos, Fabrício Rodrigues; de Thoisy, Benoît

    2013-01-01

    The leatherback turtle Dermochelys coriacea is the most widely distributed sea turtle species in the world. It exhibits complex life traits: female homing and migration, migrations of juveniles and males that remain poorly known, and a strong climatic influence on resources, breeding success and sex-ratio. It is consequently challenging to understand population dynamics. Leatherbacks are critically endangered, yet the group from the Northwest Atlantic is currently considered to be under lower risk than other populations while hosting some of the largest rookeries. Here, we investigated the genetic diversity and the demographic history of contrasted rookeries from this group, namely two large nesting populations in French Guiana, and a smaller one in the French West Indies. We used 10 microsatellite loci, of which four are newly isolated, and mitochondrial DNA sequences of the control region and cytochrome b. Both mitochondrial and nuclear markers revealed that the Northwest Atlantic stock of leatherbacks derives from a single ancestral origin, but show current genetic structuration at the scale of nesting sites, with the maintenance of migrants amongst rookeries. Low nuclear genetic diversities are related to founder effects that followed consequent bottlenecks during the late Pleistocene/Holocene. Most probably in response to climatic oscillations, with a possible influence of early human hunting, female effective population sizes collapsed from 2 million to 200. Evidence of founder effects and high numbers of migrants make it possible to reconsider the population dynamics of the species, formerly considered as a metapopulation model: we propose a more relaxed island model, which we expect to be a key element in the currently observed recovering of populations. Although these Northwest Atlantic rookeries should be considered as a single evolutionary unit, we stress that local conservation efforts remain necessary since each nesting site hosts part of the genetic diversity and species history. PMID:23516429

  1. Genetic Structure and Demographic History Should Inform Conservation: Chinese Cobras Currently Treated as Homogenous Show Population Divergence

    PubMed Central

    Lin, Long-Hui; Qu, Yan-Fu; Li, Hong; Zhou, Kai-Ya; Ji, Xiang

    2012-01-01

    An understanding of population structure and genetic diversity is crucial for wildlife conservation and for determining the integrity of wildlife populations. The vulnerable Chinese cobra (Naja atra) has a distribution from the mouth of the Yangtze River down to northern Vietnam and Laos, within which several large mountain ranges and water bodies may influence population structure. We combined 12 microsatellite loci and 1117 bp of the mitochondrial cytochrome b gene to explore genetic structure and demographic history in this species, using 269 individuals from various localities in Mainland China and Vietnam. High levels of genetic variation were identified for both mtDNA and microsatellites. mtDNA data revealed two main (Vietnam + southern China + southwestern China; eastern + southeastern China) and one minor (comprising only two individuals from the westernmost site) clades. Microsatellite data divided the eastern + southeastern China clade further into two genetic clusters, which include individuals from the eastern and southeastern regions, respectively. The Luoxiao and Nanling Mountains may be important barriers affecting the diversification of lineages. In the haplotype network of cytchrome b, many haplotypes were represented within a “star” cluster and this and other tests suggest recent expansion. However, microsatellite analyses did not yield strong evidence for a recent bottleneck for any population or genetic cluster. The three main clusters identified here should be considered as independent management units for conservation purposes. The release of Chinese cobras into the wild should cease unless their origin can be determined, and this will avoid problems arising from unnatural homogenization. PMID:22558439

  2. Low genetic diversity in wide-spread Eurasian liver fluke Opisthorchis felineus suggests special demographic history of this trematode species.

    PubMed

    Brusentsov, Ilja I; Katokhin, Alexey V; Brusentsova, Irina V; Shekhovtsov, Sergei V; Borovikov, Sergei N; Goncharenko, Grigoriy G; Lider, Lyudmila A; Romashov, Boris V; Rusinek, Olga T; Shibitov, Samat K; Suleymanov, Marat M; Yevtushenko, Andrey V; Mordvinov, Viatcheslav A

    2013-01-01

    Opisthorchis felineus or Siberian liver fluke is a trematode parasite (Opisthorchiidae) that infects the hepato-biliary system of humans and other mammals. Despite its public health significance, this wide-spread Eurasian species is one of the most poorly studied human liver flukes and nothing is known about its population genetic structure and demographic history. In this paper, we attempt to fill this gap for the first time and to explore the genetic diversity in O. felineus populations from Eastern Europe (Ukraine, European part of Russia), Northern Asia (Siberia) and Central Asia (Northern Kazakhstan). Analysis of marker DNA fragments from O. felineus mitochondrial cytochrome c oxidase subunit 1 and 3 (cox1, cox3) and nuclear rDNA internal transcribed spacer 1 (ITS1) sequences revealed that genetic diversity is very low across the large geographic range of this species. Microevolutionary processes in populations of trematodes may well be influenced by their peculiar biology. Nevertheless, we suggest that lack of population genetics structure observed in O. felineus can be primarily explained by the Pleistocene glacial events and subsequent sudden population growth from a very limited group of founders. Rapid range expansion of O. felineus through Asian and European territories after severe bottleneck points to a high dispersal potential of this trematode species. PMID:23634228

  3. Low Genetic Diversity in Wide-Spread Eurasian Liver Fluke Opisthorchis felineus Suggests Special Demographic History of This Trematode Species

    PubMed Central

    Brusentsov, Ilja I.; Katokhin, Alexey V.; Brusentsova, Irina V.; Shekhovtsov, Sergei V.; Borovikov, Sergei N.; Goncharenko, Grigoriy G.; Lider, Lyudmila A.; Romashov, Boris V.; Rusinek, Olga T.; Shibitov, Samat K.; Suleymanov, Marat M.; Yevtushenko, Andrey V.; Mordvinov, Viatcheslav A.

    2013-01-01

    Opisthorchis felineus or Siberian liver fluke is a trematode parasite (Opisthorchiidae) that infects the hepato-biliary system of humans and other mammals. Despite its public health significance, this wide-spread Eurasian species is one of the most poorly studied human liver flukes and nothing is known about its population genetic structure and demographic history. In this paper, we attempt to fill this gap for the first time and to explore the genetic diversity in O. felineus populations from Eastern Europe (Ukraine, European part of Russia), Northern Asia (Siberia) and Central Asia (Northern Kazakhstan). Analysis of marker DNA fragments from O. felineus mitochondrial cytochrome c oxidase subunit 1 and 3 (cox1, cox3) and nuclear rDNA internal transcribed spacer 1 (ITS1) sequences revealed that genetic diversity is very low across the large geographic range of this species. Microevolutionary processes in populations of trematodes may well be influenced by their peculiar biology. Nevertheless, we suggest that lack of population genetics structure observed in O. felineus can be primarily explained by the Pleistocene glacial events and subsequent sudden population growth from a very limited group of founders. Rapid range expansion of O. felineus through Asian and European territories after severe bottleneck points to a high dispersal potential of this trematode species. PMID:23634228

  4. Revealing the maternal demographic history of Panthera leo using ancient DNA and a spatially explicit genealogical analysis

    PubMed Central

    2014-01-01

    Background Understanding the demographic history of a population is critical to conservation and to our broader understanding of evolutionary processes. For many tropical large mammals, however, this aim is confounded by the absence of fossil material and by the misleading signal obtained from genetic data of recently fragmented and isolated populations. This is particularly true for the lion which as a consequence of millennia of human persecution, has large gaps in its natural distribution and several recently extinct populations. Results We sequenced mitochondrial DNA from museum-preserved individuals, including the extinct Barbary lion (Panthera leo leo) and Iranian lion (P. l. persica), as well as lions from West and Central Africa. We added these to a broader sample of lion sequences, resulting in a data set spanning the historical range of lions. Our Bayesian phylogeographical analyses provide evidence for highly supported, reciprocally monophyletic lion clades. Using a molecular clock, we estimated that recent lion lineages began to diverge in the Late Pleistocene. Expanding equatorial rainforest probably separated lions in South and East Africa from other populations. West African lions then expanded into Central Africa during periods of rainforest contraction. Lastly, we found evidence of two separate incursions into Asia from North Africa, first into India and later into the Middle East. Conclusions We have identified deep, well-supported splits within the mitochondrial phylogeny of African lions, arguing for recognition of some regional populations as worthy of independent conservation. More morphological and nuclear DNA data are now needed to test these subdivisions. PMID:24690312

  5. Speciation, population structure, and demographic history of the Mojave Fringe-toed Lizard (Uma scoparia), a species of conservation concern.

    PubMed

    Gottscho, Andrew D; Marks, Sharyn B; Jennings, W Bryan

    2014-06-01

    The North American deserts were impacted by both Neogene plate tectonics and Quaternary climatic fluctuations, yet it remains unclear how these events influenced speciation in this region. We tested published hypotheses regarding the timing and mode of speciation, population structure, and demographic history of the Mojave Fringe-toed Lizard (Uma scoparia), a sand dune specialist endemic to the Mojave Desert of California and Arizona. We sampled 109 individual lizards representing 22 insular dune localities, obtained DNA sequences for 14 nuclear loci, and found that U. scoparia has low genetic diversity relative to the U. notata species complex, comparable to that of chimpanzees and southern elephant seals. Analyses of genotypes using Bayesian clustering algorithms did not identify discrete populations within U. scoparia. Using isolation-with-migration (IM) models and a novel coalescent-based hypothesis testing approach, we estimated that U. scoparia diverged from U. notata in the Pleistocene epoch. The likelihood ratio test and the Akaike Information Criterion consistently rejected nested speciation models that included parameters for migration and population growth of U. scoparia. We reject the Neogene vicariance hypothesis for the speciation of U. scoparia and define this species as a single evolutionarily significant unit for conservation purposes. PMID:25360285

  6. Speciation, population structure, and demographic history of the Mojave Fringe-toed Lizard (Uma scoparia), a species of conservation concern

    PubMed Central

    Gottscho, Andrew D; Marks, Sharyn B; Jennings, W Bryan

    2014-01-01

    The North American deserts were impacted by both Neogene plate tectonics and Quaternary climatic fluctuations, yet it remains unclear how these events influenced speciation in this region. We tested published hypotheses regarding the timing and mode of speciation, population structure, and demographic history of the Mojave Fringe-toed Lizard (Uma scoparia), a sand dune specialist endemic to the Mojave Desert of California and Arizona. We sampled 109 individual lizards representing 22 insular dune localities, obtained DNA sequences for 14 nuclear loci, and found that U. scoparia has low genetic diversity relative to the U. notata species complex, comparable to that of chimpanzees and southern elephant seals. Analyses of genotypes using Bayesian clustering algorithms did not identify discrete populations within U. scoparia. Using isolation-with-migration (IM) models and a novel coalescent-based hypothesis testing approach, we estimated that U. scoparia diverged from U. notata in the Pleistocene epoch. The likelihood ratio test and the Akaike Information Criterion consistently rejected nested speciation models that included parameters for migration and population growth of U. scoparia. We reject the Neogene vicariance hypothesis for the speciation of U. scoparia and define this species as a single evolutionarily significant unit for conservation purposes. PMID:25360285

  7. Genetic structure and demographic history should inform conservation: Chinese cobras currently treated as homogenous show population divergence.

    PubMed

    Lin, Long-Hui; Qu, Yan-Fu; Li, Hong; Zhou, Kai-Ya; Ji, Xiang

    2012-01-01

    An understanding of population structure and genetic diversity is crucial for wildlife conservation and for determining the integrity of wildlife populations. The vulnerable Chinese cobra (Naja atra) has a distribution from the mouth of the Yangtze River down to northern Vietnam and Laos, within which several large mountain ranges and water bodies may influence population structure. We combined 12 microsatellite loci and 1117 bp of the mitochondrial cytochrome b gene to explore genetic structure and demographic history in this species, using 269 individuals from various localities in Mainland China and Vietnam. High levels of genetic variation were identified for both mtDNA and microsatellites. mtDNA data revealed two main (Vietnam + southern China + southwestern China; eastern + southeastern China) and one minor (comprising only two individuals from the westernmost site) clades. Microsatellite data divided the eastern + southeastern China clade further into two genetic clusters, which include individuals from the eastern and southeastern regions, respectively. The Luoxiao and Nanling Mountains may be important barriers affecting the diversification of lineages. In the haplotype network of cytchrome b, many haplotypes were represented within a "star" cluster and this and other tests suggest recent expansion. However, microsatellite analyses did not yield strong evidence for a recent bottleneck for any population or genetic cluster. The three main clusters identified here should be considered as independent management units for conservation purposes. The release of Chinese cobras into the wild should cease unless their origin can be determined, and this will avoid problems arising from unnatural homogenization. PMID:22558439

  8. Invasion history and demographic pattern of Cryphonectria hypovirus 1 across European populations of the chestnut blight fungus

    PubMed Central

    Bryner, Sarah F; Rigling, Daniel; Brunner, Patrick C

    2012-01-01

    We reconstructed the invasion history of the fungal virus Cryphonectria hypovirus 1 (CHV-1) in Europe, which infects the chestnut blight fungus Cryphonectria parasitica. The pattern of virus evolution was inferred based on nucleotide sequence variation from isolates sampled across a wide area in Europe at different points in time. Phylogeny and time estimates suggested that CHV-1 was introduced together with its fungal host to Europe and that it rapidly colonized the central range along the south facing slopes of the Alps and the north-east facing slopes of the Dinaric Alps. These central populations were the source for two waves of simultaneous invasions toward the southern Balkans and Turkey, as indicated by migration rates. Our results showed that the evolutionary scenarios for CHV-1 and C. parasitica were spatially congruent. As infection with CHV-1 reduces the pathogenicity of C. parasitica toward the chestnut tree, CHV-1 invasions of the newly established C. parasitica populations probably prevented the development of devastating chestnut blight epidemics in Europe. We propose that in this, and supposedly in other pathosystems, geographic, vegetation-related, demographic, economic, and political factors may help explain the correlated invasion pattern of a parasite and its host. PMID:23301186

  9. Joints

    NSDL National Science Digital Library

    Olivia Worland (Purdue University; Biological Sciences)

    2008-06-06

    Hinge joints move only in one direction, ball-and-socket joints are free to rotate in all directions, and gliding joints are able to move forward, backward, and side to side, but do not rotate freely.

  10. The natural history of primary anterior dislocation of the glenohumeral joint in adolescence.

    PubMed

    Roberts, S B; Beattie, N; McNiven, N D; Robinson, C M

    2015-04-01

    The natural history of primary anterior dislocation of the glenohumeral joint in adolescent patients remains unclear and there is no consensus for management of these patients. The objectives of this study were to report the natural history of primary anterior dislocation of the glenohumeral joint in adolescent patients and to identify the risk factors for recurrent dislocation. We reviewed prospectively-collected clinical and radiological data on 133 adolescent patients diagnosed with a primary anterior dislocation of the glenohumeral joint who had been managed non-operatively at our hospital between 1996 and 2008. There were 115 male (86.5%) and 18 female patients (13.5%) with a mean age of 16.3 years (13 to 18) and a mean follow-up of 95.2 months (1 to 215). During follow-up, 102 (absolute incidence of 76.7%) patients had a recurrent dislocation. The median interval between primary and recurrent dislocation was ten months (95% CI 7.4 to 12.6). Applying survival analysis the likelihood of having a stable shoulder one year after the initial injury was 59% (95% CI 51.2 to 66.8), 38% (95% CI 30.2 to 45.8%) after two years, 21% (95% CI 13.2 to 28.8) after five years, and 7% (95% CI 1.1 to 12.9) after ten years. Neither age nor gender significantly predicted recurrent dislocation during follow-up. We conclude that adolescent patients with a primary anterior dislocation of the glenohumeral joint have a high rate of recurrent dislocation, which usually occurs within two years of their initial injury: these patients should be considered for early operative stabilisation. Cite this article: Bone Joint J 2015;97-B:520-6. PMID:25820892

  11. Divorcing the Late Upper Palaeolithic demographic histories of mtDNA haplogroups M1 and U6 in Africa

    PubMed Central

    2012-01-01

    Background A Southwest Asian origin and dispersal to North Africa in the Early Upper Palaeolithic era has been inferred in previous studies for mtDNA haplogroups M1 and U6. Both haplogroups have been proposed to show similar geographic patterns and shared demographic histories. Results We report here 24 M1 and 33 U6 new complete mtDNA sequences that allow us to refine the existing phylogeny of these haplogroups. The resulting phylogenetic information was used to genotype a further 131 M1 and 91 U6 samples to determine the geographic spread of their sub-clades. No southwest Asian specific clades for M1 or U6 were discovered. U6 and M1 frequencies in North Africa, the Middle East and Europe do not follow similar patterns, and their sub-clade divisions do not appear to be compatible with their shared history reaching back to the Early Upper Palaeolithic. The Bayesian Skyline Plots testify to non-overlapping phases of expansion, and the haplogroups’ phylogenies suggest that there are U6 sub-clades that expanded earlier than those in M1. Some M1 and U6 sub-clades could be linked with certain events. For example, U6a1 and M1b, with their coalescent ages of ~20,000–22,000 years ago and earliest inferred expansion in northwest Africa, could coincide with the flourishing of the Iberomaurusian industry, whilst U6b and M1b1 appeared at the time of the Capsian culture. Conclusions Our high-resolution phylogenetic dissection of both haplogroups and coalescent time assessments suggest that the extant main branching pattern of both haplogroups arose and diversified in the mid-later Upper Palaeolithic, with some sub-clades concomitantly with the expansion of the Iberomaurusian industry. Carriers of these maternal lineages have been later absorbed into and diversified further during the spread of Afro-Asiatic languages in North and East Africa. PMID:23206491

  12. Upper Palaeolithic population histories of Southwestern France: a comparison of the demographic signatures of 14C date distributions and archaeological site counts

    E-print Network

    French, Jennifer C.; Collins, Christina

    2016-01-14

    of re h, Department of Archaeology and Anthropology, University of Cambridge, Downing Street, Cambridge, CB2 3ER, UK b School of Archaeology, Classics and Egyptology, Unive a r t i c l e i n f o Article history: Received 13 September 2014 Received... variability and human demographic fluctuations (Munoz et al., 2010; Kelly et al., 2013; Schmidt et al., 2012; Tallavaara and Sepp€a, 2011). Despite both methods sharing the same underlying assumption of the relationship between the archaeological proxy...

  13. Understanding patterns of genetic diversity in the oak gallwasp Biorhiza pallida: demographic history or a Wolbachia selective sweep? 

    E-print Network

    Rokas, Antonis; Atkinson, Rachel J; Brown, Gordon S; West, Stuart A; Stone, Graham A

    2001-01-01

    The endosymbiont Walbachia can be responsible for selective sweeps on mitochondrial DNA variability within species. Similar signals can also result from demographic processes, although crucially the latter affect nuclear ...

  14. Classification of metatarsophalangeal joint plantar plate injuries: history and physical examination variables.

    PubMed

    Nery, Caio; Coughlin, Michael J; Baumfeld, Daniel; Raduan, Fernando C; Mann, Tania Szejnfeld; Catena, Fernanda

    2014-01-01

    Although metatarsophalangeal (MTP) plantar plate tears are common, they are still often missed. The purpose of this study is to find the best clinical variables to define and grade the plantar plate injuries. Sixty-eight patients (100 MTP joints) were graded arthroscopically and divided into five groups (0 to IV) according to the anatomical classification. Their medical records were reviewed to establish correlations of clinical findings with the anatomical lesions. The positive correlations found were acute pain, widening of the interdigital space, loss of ground touch, positivity of the MTP joint drawer test, reduction of the toe purchase, and toe supination. The drawer test is the most reliable and accurate tool to classify and grade the plantar plate lesion, followed by ground touch and rotational deformities. It is possible to improve the accuracy of diagnosis of plantar plate tears by means of the combination of both clinical history and physical examination data. PMID:25785472

  15. Demographic history, geographical distribution and reproductive isolation of distinct lineages of blue rockfish (Sebastes mystinus), a marine fish with a high dispersal potential.

    PubMed

    Burford, Martha O

    2009-07-01

    Understanding the barriers to genetic exchange in taxonomic groups that have a high dispersal potential will provide critical information on speciation in general. Blue rockfish (Sebastes mystinus) are good taxa to examine speciation because they are nonmigratory inhabitants of shallow rocky reef habitats along the eastern North Pacific with a pelagic larval stage lasting 3-5 months. The goal of this study was to analyse the evolutionary history and distribution patterns of different lineages within S. mystinus described previously and use this information to understand the speciation process in this group of high dispersal fish. The molecular data derived from specimens sampled over approximately 1650 km of the S. mystinus range revealed a northerly and southerly distribution for the two lineages. Almost equal frequencies of both lineages occurred at centrally located sample locations, with evidence of reproductive isolation between the lineages. A demographic analysis showed that the two lineages diverged and experienced sudden expansion prior to the last glacial maximum, which affected the observed pattern of genetic structure. The spatial distribution, demographic history and degree of genetic distinctiveness found from the genetic analysis, despite the high potential for dispersal in S. mystinus, suggest both lineages diverged in allopatry. PMID:19467131

  16. Socio-Demographic, Clinical and Behavioral Characteristics Associated with a History of Suicide Attempts among Psychiatric Outpatients: A Case Control Study in a Northern Mexican City

    PubMed Central

    Alvarado-Esquivel, Cosme; Sánchez-Anguiano, Luis Francisco; Arnaud-Gil, Carlos Alberto; Hernández-Tinoco, Jesús; Molina-Espinoza, Luis Fernando; Rábago-Sánchez, Elizabeth

    2014-01-01

    Background: Little is known about the epidemiology of suicide attempts among psychiatric outpatients in Mexico. This study was aimed to determine the socio-demographic, clinical and behavioral characteristics associated with suicide attempts in psychiatric outpatients in two public hospitals in Durango, Mexico. Methods: Two hundred seventy six psychiatric outpatients (154 suicide attempters and 122 patients without suicide attempt history) attended the two public hospitals in Durango City, Mexico were included in this study. Socio-demographic, clinical and behavioral characteristics were obtained retrospectively from all outpatients and compared in relation to the presence or absence of suicide attempt history. Results: Increased prevalence of suicide attempts was associated with mental and behavioral disorders due to psychoactive substance use (F10-19) (P=0.01), schizophrenia, schizotypal and delusional disorders (F20-29) (P=0.02), mood (affective) disorders (F30-39) (P<0.001), and disorders of adult personality and behavior (F60-69) (P<0.001). Multivariate analysis showed that suicide attempts were associated with young age (OR=1.21, 95% CI: 1.06-1.39; P=0.003), female gender (OR=2.98, 95% CI: 1.55-5.73; P=0.001), urban residence (OR=2.31, 95% CI: 1.17-4.57; P=0.01), memory impairment (OR=1.91, 95% CI: 1.07-3.40; P=0.02), alcohol consumption (OR=2.39, 95% CI: 1.21-4.70; P=0.01), and sexual promiscuity (OR=3.90, 95% CI: 1.74-8.77; P<0.001). Conclusions: We report the association of suicide attempts with socio-demographic, clinical and behavioral characteristics in psychiatric outpatients in Mexico. Results may be useful for an optimal planning of preventive measures against suicide attempts in psychiatric outpatients. PMID:24711751

  17. Life-history and demographic variation in an alpine specialist at the latitudinal extremes of the range

    Microsoft Academic Search

    Scott Wilson; Kathy Martin

    2011-01-01

    Alpine environments are unique systems to examine variation in life-history strategies because temperature and seasonality\\u000a are similar across broad latitudinal gradients. We studied the life-history strategies, demography and population growth of\\u000a white-tailed ptarmigan Lagopus leucura, an alpine specialist, at the latitudinal extremes of the range in the Yukon (YK, studied from 2004 to 2008) and Colorado\\u000a (CO, 1987–1996). The two

  18. Strong population genetic structure and contrasting demographic histories for the small-spotted catshark (Scyliorhinus canicula) in the Mediterranean Sea.

    PubMed

    Kousteni, V; Kasapidis, P; Kotoulas, G; Megalofonou, P

    2015-03-01

    Coastal and demersal chondrichthyans, such as the small-spotted catshark, are expected to exhibit genetic differentiation in areas of complex geomorphology like the Mediterranean Basin because of their limited dispersal ability. To test this hypothesis, we used a fragment of the mitochondrial cytochrome c oxidase subunit I gene and 12 nuclear microsatellite loci in order to investigate the genetic structure and historical demography of this species, and to identify potential barriers to gene flow. Samples were collected from the Balearic Islands, the Algerian Basin, the Ionian Sea, the Corinthian Gulf and various locations across the Aegean Sea. Additional sequences from the Atlantic and the Levantine Basin retrieved from GenBank were included in the mitochondrial DNA analysis. Both mitochondrial and nuclear microsatellite DNA data revealed a strong genetic subdivision, mainly between the western and eastern Mediterranean, whereas the Levantine Basin shared haplotypes with both areas. The geographic isolation of the Mediterranean basins seems to enforce the population genetic differentiation of the species, with the deep sea acting as a strong barrier to its dispersal. Contrasting historical demographic patterns were also observed in different parts of the species' distribution, most notably a population growth trend in the western Mediterranean/Atlantic area and a slight decreasing one in the Aegean Sea. The different effects of the Pleistocene glacial periods on the habitat availability may explain the contrasting demographic patterns observed. The current findings suggest that the small-spotted catshark exhibits several genetic stocks in the Mediterranean, although further study is needed. PMID:25469687

  19. Did glacial advances during the Pleistocene influence differently the demographic histories of benthic and pelagic Antarctic shelf fishes? – Inferences from intraspecific mitochondrial and nuclear DNA sequence diversity

    PubMed Central

    Janko, Karel; Lecointre, Guillaume; DeVries, Arthur; Couloux, Arnaud; Cruaud, Corinne; Marshall, Craig

    2007-01-01

    Background Circum-Antarctic waters harbour a rare example of a marine species flock – the Notothenioid fish, most species of which are restricted to the continental shelf. It remains an open question as to how they survived Pleistocene climatic fluctuations characterised by repeated advances of continental glaciers as far as the shelf break that probably resulted in a loss of habitat for benthic organisms. Pelagic ecosystems, on the other hand, might have flourished during glacial maxima due to the northward expansion of Antarctic polar waters. In order to better understand the role of ecological traits in Quaternary climatic fluctuations, we performed demographic analyses of populations of four fish species from the tribe Trematominae, including both fully benthic and pelagic species using the mitochondrial cytochrome b gene and an intron from the nuclear S7 gene. Results Nuclear and cytoplasmic markers showed differences in the rate and time of population expansions as well as the likely population structure. Neutrality tests suggest that such discordance comes from different coalescence dynamics of each marker, rather than from selective pressure. Demographic analyses based on intraspecific DNA diversity suggest a recent population expansion in both benthic species, dated by the cyt b locus to the last glacial cycle, whereas the population structure of pelagic feeders either did not deviate from a constant-size model or indicated that the onset of the major population expansion of these species by far predated those of the benthic species. Similar patterns were apparent even when comparing previously published data on other Southern Ocean organisms, but we observed considerable heterogeneity within both groups with regard to the onset of major demographic events and rates. Conclusion Our data suggest benthic and pelagic species reacted differently to the Pleistocene ice-sheet expansions that probably significantly reduced the suitable habitat for benthic species. However, the asynchronous timing of major demographic events observed in different species within both "ecological guilds", imply that the species examined here may have different population and evolutionary histories, and that more species should be analysed in order to more precisely assess the role of life history in the response of organisms to climatic changes. PMID:17997847

  20. Pragmatic Perspective on Conservation Genetics and Demographic History of the Last Surviving Population of Kashmir Red Deer (Cervus elaphus hanglu) in India

    PubMed Central

    Mukesh; Kumar, Ved P.; Sharma, Lalit K.; Shukla, Malay; Sathyakumar, Sambandam

    2015-01-01

    The hangul (Cervus elaphus hanglu) is of great conservation concern because it represents the easternmost and only hope for an Asiatic survivor of the red deer species in the Indian subcontinent. Despite the rigorous conservation efforts of the Department of Wildlife Protection in Jammu & Kashmir, the hangul population has experienced a severe decline in numbers and range contraction in the past few decades. The hangul population once abundant in the past has largely become confined to the Dachigam landscape, with a recent population estimate of 218 individuals. We investigated the genetic variability and demographic history of the hangul population and found that it has shown a relatively low diversity estimates when compared to other red deer populations of the world. Neutrality tests, which are used to evaluate demographic effects, did not support population expansion, and the multimodal pattern of mismatch distribution indicated that the hangul population is under demographic equilibrium. Furthermore, the hangul population did not exhibit any signature of bottleneck footprints in the past, and Coalescent Bayesian Skyline plot analysis revealed that the population had not experienced any dramatic changes in the effective population size over the last several thousand years. We observed a strong evidence of sub-structuring in the population, wherein the majority of individuals were assigned to different clusters in Bayesian cluster analysis. Population viability analysis demonstrated insignificant changes in the mean population size, with a positive growth rate projected for the next hundred years. We discuss the phylogenetic status of hangul for the first time among the other red deer subspecies of the world and strongly recommend to upgrade hangul conservation status under IUCN that should be discrete from the other red deer subspecies of the world to draw more conservation attention from national and international bodies. PMID:25671567

  1. Population genomics shed light on the demographic and adaptive histories of European invasion in the Pacific oyster, Crassostrea gigas

    PubMed Central

    Rohfritsch, Audrey; Bierne, Nicolas; Boudry, Pierre; Heurtebise, Serge; Cornette, Florence; Lapčgue, Sylvie

    2013-01-01

    Crassostrea gigas originated from the Pacific coast of Asia, but was introduced into several European countries in the early 1970s. Natural populations have now spread across the length of the western seaboard of Europe. To elucidate the demographic and selective processes at play during this rapid expansion, genome-scan analysis was performed on different populations. High diversities and low differentiation were observed overall, but significant genetic differentiation was found among newly established populations and between the newly established northern group and a nearly panmictic group composed of southern European populations and a population from Japan. Loss of genetic diversity was also seen in the north, likely caused by founder events during colonization. The few strongly supported outlier loci revealed a genetic structure uncorrelated with the north/south differentiation, but grouping two samples from the Danish fjords (northern group) and one from the Dutch Scheldt estuary (southern group) with the one from Japan. These findings might reflect the following: (i) parallel adaptation to similar environmental pressures (fjord-like environment) within each of the two groups or (ii) a footprint of a secondary introduction of an alternative genomic background maintained by multifarious isolation factors. Our results call for a closer examination of adaptive genetic structure in the area of origin. PMID:24187588

  2. When competition eclipses cooperation: an event history analysisof joint venture failure

    Microsoft Academic Search

    Seung Ho Park; Michael V. Russo

    1996-01-01

    Why do so many joint ventures fail? Despite the fact that their success is the exception rather than the rule, the literature on why joint venture performance has been so poor remains fragmentary. We address this issue, adopting a transaction-cost economics perspective and modeling joint ventures as governance structures that blend the advantages and drawbacks of both markets and hierarchies.

  3. Selection and demographic history shape the molecular evolution of the gamete compatibility protein bindin in Pisaster sea stars

    PubMed Central

    Popovic, Iva; Marko, Peter B; Wares, John P; Hart, Michael W

    2014-01-01

    Reproductive compatibility proteins have been shown to evolve rapidly under positive selection leading to reproductive isolation, despite the potential homogenizing effects of gene flow. This process has been implicated in both primary divergence among conspecific populations and reinforcement during secondary contact; however, these two selective regimes can be difficult to discriminate from each other. Here, we describe the gene that encodes the gamete compatibility protein bindin for three sea star species in the genus Pisaster. First, we compare the full-length bindin-coding sequence among all three species and analyze the evolutionary relationships between the repetitive domains of the variable second bindin exon. The comparison suggests that concerted evolution of repetitive domains has an effect on bindin divergence among species and bindin variation within species. Second, we characterize population variation in the second bindin exon of two species: We show that positive selection acts on bindin variation in Pisaster ochraceus but not in Pisaster brevispinus, which is consistent with higher polyspermy risk in P. ochraceus. Third, we show that there is no significant genetic differentiation among populations and no apparent effect of sympatry with congeners that would suggest selection based on reinforcement. Fourth, we combine bindin and cytochrome c oxidase 1 data in isolation-with-migration models to estimate gene flow parameter values and explore the historical demographic context of our positive selection results. Our findings suggest that positive selection on bindin divergence among P. ochraceus alleles can be accounted for in part by relatively recent northward population expansions that may be coupled with the potential homogenizing effects of concerted evolution. PMID:24967076

  4. Phylogeography across a continent: the evolutionary and demographic history of the North American racer (Serpentes: Colubridae: Coluber constrictor).

    PubMed

    Burbrink, Frank T; Fontanella, Frank; Alexander Pyron, R; Guiher, Timothy J; Jimenez, Cynthia

    2008-04-01

    Most phylogeographic studies examine organisms that do not have transcontinental distributions and therefore the genetic and temporal effects of barriers across an entire continent cannot be assessed with respect to a single species. We examined the phylogeographic structure, lineage age, and historical demography using sequences from the mtDNA cytochrome b gene of the widespread North American racer (Coluber constrictor), one of the few abundant transcontinental snakes that occurs throughout many diverse biomes. Our results indicate that this complex is comprised of six lineages differing greatly in geographic extent, with the largest (a central US clade) being approximately 26 times greater than the smallest (a lineage restricted to the Florida Panhandle and nearby portions of adjacent States). Most of the six lineages appear to be separated at previously identified genetic barriers for several vertebrates with similar ranges. Lineage diversification in this species began in the late Miocene, separating populations in the Florida Peninsula from the remainder of the US. Diversification of lineages continued throughout the Pliocene and early Pleistocene. Four of the six lineages occur east of the Mississippi River, with only two distinctly young ( approximately 1.5 mya) lineages found west of the Mississippi River (one occurs west of Continental Divide). All methods of demographic inference, including the mismatch distribution, Fu and Li's D and Tajima's D , and Bayesian skyline plots revealed population expansion occurring in the mid-to-late Pleistocene for every lineage, regardless of size or proximity to formerly glaciated areas. Population expansion for lineages found east of the Mississippi River occurred earlier and was much greater than those found west of the River. PMID:18093846

  5. Evolutionary history of a widespread Indo-Pacific goby: the role of Pleistocene sea-level changes on demographic contraction/expansion dynamics.

    PubMed

    Hoareau, Thierry Bernard; Boissin, Emilie; Berrebi, Patrick

    2012-01-01

    Compared to endemics, widespread species are of particular interest to retrace recent evolutionary history. These species have a large population size which provides a clearer genetic signature of past events. Moreover, their wide geographic range increases the potential occurrence of evolutionary events (expansion, divergence, etc.). Here, we used several coalescent-based methods to disentangle the evolutionary history of a widespread amphidromous goby (Sicyopterus lagocephalus), in the light of sea-level variations during the Pleistocene. Using 75 samples recovered from three biogeographic regions (Western Indian Ocean, Melanesia and Polynesia), we analysed a portion of the cytochromeb gene and confirmed three major haplogroups, each specific to a region. Furthermore, we found that: (1) the Melanesian haplogroup was the oldest while the two peripheral regions hosted daughter haplogroups; (2) two centrifugal colonisation events occurred from Melanesia to the periphery, each synchronised with periods of strong paleo-ENSO episodes; (3) the demographic contraction-expansion events were linked to Pleistocene sea-level changes; (4) Melanesia and Polynesia acted as efficient refuges during the Last Glacial Maximum. These results highlight the importance of studying widespread species to better understand the role of climate changes and paleo-oceanography on the evolution of biodiversity. PMID:22037473

  6. Human paternal and maternal demographic histories: insights from high-resolution Y chromosome and mtDNA sequences

    PubMed Central

    2014-01-01

    Background Comparisons of maternally-inherited mitochondrial DNA (mtDNA) and paternally-inherited non-recombining Y chromosome (NRY) variation have provided important insights into the impact of sex-biased processes (such as migration, residence pattern, and so on) on human genetic variation. However, such comparisons have been limited by the different molecular methods typically used to assay mtDNA and NRY variation (for example, sequencing hypervariable segments of the control region for mtDNA vs. genotyping SNPs and/or STR loci for the NRY). Here, we report a simple capture array method to enrich Illumina sequencing libraries for approximately 500 kb of NRY sequence, which we use to generate NRY sequences from 623 males from 51 populations in the CEPH Human Genome Diversity Panel (HGDP). We also obtained complete mtDNA genome sequences from the same individuals, allowing us to compare maternal and paternal histories free of any ascertainment bias. Results We identified 2,228 SNPs in the NRY sequences and 2,163 SNPs in the mtDNA sequences. Our results confirm the controversial assertion that genetic differences between human populations on a global scale are bigger for the NRY than for mtDNA, although the differences are not as large as previously suggested. More importantly, we find substantial regional variation in patterns of mtDNA versus NRY variation. Model-based simulations indicate very small ancestral effective population sizes (<100) for the out-of-Africa migration as well as for many human populations. We also find that the ratio of female effective population size to male effective population size (Nf/Nm) has been greater than one throughout the history of modern humans, and has recently increased due to faster growth in Nf than Nm. Conclusions The NRY and mtDNA sequences provide new insights into the paternal and maternal histories of human populations, and the methods we introduce here should be widely applicable for further such studies. PMID:25254093

  7. Historical DNA reveals the demographic history of Atlantic cod (Gadus morhua) in medieval and early modern Iceland

    PubMed Central

    Ólafsdóttir, Guđbjörg Ásta; Westfall, Kristen M.; Edvardsson, Ragnar; Pálsson, Snćbjörn

    2014-01-01

    Atlantic cod (Gadus morhua) vertebrae from archaeological sites were used to study the history of the Icelandic Atlantic cod population in the time period of 1500–1990. Specifically, we used coalescence modelling to estimate population size and fluctuations from the sequence diversity at the cytochrome b (cytb) and Pantophysin I (PanI) loci. The models are consistent with an expanding population during the warm medieval period, large historical effective population size (NE), a marked bottleneck event at 1400–1500 and a decrease in NE in early modern times. The model results are corroborated by the reduction of haplotype and nucleotide variation over time and pairwise population distance as a significant portion of nucleotide variation partitioned across the 1550 time mark. The mean age of the historical fished stock is high in medieval times with a truncation in age in early modern times. The population size crash coincides with a period of known cooling in the North Atlantic, and we conclude that the collapse may be related to climate or climate-induced ecosystem change. PMID:24403343

  8. Ancestral polymorphisms and sex-biased migration shaped the demographic history of brown bears and polar bears.

    PubMed

    Nakagome, Shigeki; Mano, Shuhei; Hasegawa, Masami

    2013-01-01

    Recent studies have reported discordant gene trees in the evolution of brown bears and polar bears. Genealogical histories are different among independent nuclear loci and between biparentally inherited autosomal DNA (aDNA) and matrilineal mitochondrial DNA (mtDNA). Based on multi-locus genomic sequences from aDNA and mtDNA, we inferred the population demography of brown and polar bears and found that brown bears have 6 times (aDNA) or more than 14 times (mtDNA) larger population sizes than polar bears and that polar bear lineage is derived from within brown bear diversity. In brown bears, the effective population size ratio of mtDNA to aDNA was at least 0.62, which deviated from the expected value of 0.25, suggesting matriarchal population due to female philopatry and male-biased migration. These results emphasize that ancestral polymorphisms and sex-biased migration may have contributed to conflicting branching patterns in brown and polar bears across aDNA genes and mtDNA. PMID:24236053

  9. Time history analysis of axial forces (Pass Through Forces) at joints in a braced frame

    E-print Network

    Paschini, Vincent

    2012-01-01

    As buildings keep getting taller, traditional braced lateral systems take more loads. This generates a phenomenon at every joint of a frame called "Pass Through Force". Pass through forces come from the transfer of axial ...

  10. Demographic Research

    NSDL National Science Digital Library

    Demographic Research is a newly launched, peer-reviewed online journal of the population sciences published by the Max Planck Institute for Demographic Research in Rostock, Germany. The first article in Volume One (covering May 1, 1999 to December 31, 1999) has recently been posted: Cancer Rates over Age, Time, and Place: Insights from Stochastic Models of Heterogeneous Populations by James W. Vaupel and Anatoli I. Yashin. Articles are available in both HTML and .pdf formats. The Website provides detailed information about the journal's purpose, mission, submission guidelines, and review process.

  11. Genetic structure and demographic history reveal migration of the diamondback moth Plutella xylostella (Lepidoptera: Plutellidae) from the southern to northern regions of China.

    PubMed

    Wei, Shu-Jun; Shi, Bao-Cai; Gong, Ya-Jun; Jin, Gui-Hua; Chen, Xue-Xin; Meng, Xiang-Feng

    2013-01-01

    The diamondback moth Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae) is one of the most destructive insect pests of cruciferous plants worldwide. Biological, ecological and genetic studies have indicated that this moth is migratory in many regions around the world. Although outbreaks of this pest occur annually in China and cause heavy damage, little is known concerning its migration. To better understand its migration pattern, we investigated the population genetic structure and demographic history of the diamondback moth by analyzing 27 geographical populations across China using four mitochondrial genes and nine microsatellite loci. The results showed that high haplotype diversity and low nucleotide diversity occurred in the diamondback moth populations, a finding that is typical for migratory species. No genetic differentiation among all populations and no correlation between genetic and geographical distance were found. However, pairwise analysis of the mitochondrial genes has indicated that populations from the southern region were more differentiated than those from the northern region. Gene flow analysis revealed that the effective number of migrants per generation into populations of the northern region is very high, whereas that into populations of the southern region is quite low. Neutrality testing, mismatch distribution and Bayesian Skyline Plot analyses based on mitochondrial genes all revealed that deviation from Hardy-Weinberg equilibrium and sudden expansion of the effective population size were present in populations from the northern region but not in those from the southern region. In conclusion, all our analyses strongly demonstrated that the diamondback moth migrates within China from the southern to northern regions with rare effective migration in the reverse direction. Our research provides a successful example of using population genetic approaches to resolve the seasonal migration of insects. PMID:23565158

  12. Genetic Structure and Demographic History Reveal Migration of the Diamondback Moth Plutella xylostella (Lepidoptera: Plutellidae) from the Southern to Northern Regions of China

    PubMed Central

    Wei, Shu-Jun; Shi, Bao-Cai; Gong, Ya-Jun; Jin, Gui-Hua; Chen, Xue-Xin; Meng, Xiang-Feng

    2013-01-01

    The diamondback moth Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae) is one of the most destructive insect pests of cruciferous plants worldwide. Biological, ecological and genetic studies have indicated that this moth is migratory in many regions around the world. Although outbreaks of this pest occur annually in China and cause heavy damage, little is known concerning its migration. To better understand its migration pattern, we investigated the population genetic structure and demographic history of the diamondback moth by analyzing 27 geographical populations across China using four mitochondrial genes and nine microsatellite loci. The results showed that high haplotype diversity and low nucleotide diversity occurred in the diamondback moth populations, a finding that is typical for migratory species. No genetic differentiation among all populations and no correlation between genetic and geographical distance were found. However, pairwise analysis of the mitochondrial genes has indicated that populations from the southern region were more differentiated than those from the northern region. Gene flow analysis revealed that the effective number of migrants per generation into populations of the northern region is very high, whereas that into populations of the southern region is quite low. Neutrality testing, mismatch distribution and Bayesian Skyline Plot analyses based on mitochondrial genes all revealed that deviation from Hardy-Weinberg equilibrium and sudden expansion of the effective population size were present in populations from the northern region but not in those from the southern region. In conclusion, all our analyses strongly demonstrated that the diamondback moth migrates within China from the southern to northern regions with rare effective migration in the reverse direction. Our research provides a successful example of using population genetic approaches to resolve the seasonal migration of insects. PMID:23565158

  13. Patterns of Variation at Ustilago maydis Virulence Clusters 2A and 19A Largely Reflect the Demographic History of Its Populations

    PubMed Central

    Kellner, Ronny; Hanschke, Christian; Begerow, Dominik

    2014-01-01

    The maintenance of an intimate interaction between plant-biotrophic fungi and their hosts over evolutionary times involves strong selection and adaptative evolution of virulence-related genes. The highly specialised maize pathogen Ustilago maydis is assigned with a high evolutionary capability to overcome host resistances due to its high rates of sexual recombination, large population sizes and long distance dispersal. Unlike most studied fungus-plant interactions, the U. maydis – Zea mays pathosystem lacks a typical gene-for-gene interaction. It exerts a large set of secreted fungal virulence factors that are mostly organised in gene clusters. Their contribution to virulence has been experimentally demonstrated but their genetic diversity within U. maydis remains poorly understood. Here, we report on the intraspecific diversity of 34 potential virulence factor genes of U. maydis. We analysed their sequence polymorphisms in 17 isolates of U. maydis from Europe, North and Latin America. We focused on gene cluster 2A, associated with virulence attenuation, cluster 19A that is crucial for virulence, and the cluster-independent effector gene pep1. Although higher compared to four house-keeping genes, the overall levels of intraspecific genetic variation of virulence clusters 2A and 19A, and pep1 are remarkably low and commensurate to the levels of 14 studied non-virulence genes. In addition, each gene is present in all studied isolates and synteny in cluster 2A is conserved. Furthermore, 7 out of 34 virulence genes contain either no polymorphisms or only synonymous substitutions among all isolates. However, genetic variation of clusters 2A and 19A each resolve the large scale population structure of U. maydis indicating subpopulations with decreased gene flow. Hence, the genetic diversity of these virulence-related genes largely reflect the demographic history of U. maydis populations. PMID:24887029

  14. Demographic consequences of climate change and land cover help explain a history of extirpations and range contraction in a declining snake species.

    PubMed

    Pomara, Lars Y; LeDee, Olivia E; Martin, Karl J; Zuckerberg, Benjamin

    2014-07-01

    Developing conservation strategies for threatened species increasingly requires understanding vulnerabilities to climate change, in terms of both demographic sensitivities to climatic and other environmental factors, and exposure to variability in those factors over time and space. We conducted a range-wide, spatially explicit climate change vulnerability assessment for Eastern Massasauga (Sistrurus catenatus), a declining endemic species in a region showing strong environmental change. Using active season and winter adult survival estimates derived from 17 data sets throughout the species' range, we identified demographic sensitivities to winter drought, maximum precipitation during the summer, and the proportion of the surrounding landscape dominated by agricultural and urban land cover. Each of these factors was negatively associated with active season adult survival rates in binomial generalized linear models. We then used these relationships to back-cast adult survival with dynamic climate variables from 1950 to 2008 using spatially explicit demographic models. Demographic models for 189 population locations predicted known extant and extirpated populations well (AUC = 0.75), and models based on climate and land cover variables were superior to models incorporating either of those effects independently. These results suggest that increasing frequencies and severities of extreme events, including drought and flooding, have been important drivers of the long-term spatiotemporal variation in a demographic rate. We provide evidence that this variation reflects nonadaptive sensitivity to climatic stressors, which are contributing to long-term demographic decline and range contraction for a species of high-conservation concern. Range-wide demographic modeling facilitated an understanding of spatial shifts in climatic suitability and exposure, allowing the identification of important climate refugia for a dispersal-limited species. Climate change vulnerability assessment provides a framework for linking demographic and distributional dynamics to environmental change, and can thereby provide unique information for conservation planning and management. PMID:24357530

  15. Encounter history modeling of joint mark-recapture, tag-resighting and tag-recovery data under temporary emigration

    USGS Publications Warehouse

    Barker, R.J.; Burnham, K.P.; White, G.C.

    2004-01-01

    We describe a joint analysis of mark-recapture, tag-resight and tag-recovery data that directly models the encounter history of an animal. The probability of the encounter history for each animal is partitioned into survival, recapture, resighting, and recovery components, and a component for the probability that the animal is never encountered again. Temporary migration enters into the likelihood through the recapture component, and movement of marked animals in and out of the area where they are subject to capture is modeled using a Markov chain. Random temporary emigration and permanent emigration are special cases. An important feature of directly modeling the encounter histories is that covariates that are specific to individuals can be included in the analysis. The model is applied to a brown trout tagging data set and provides strong evidence of Markovian temporary emigration. The new model is needed to provide correct estimates of trout survival probabilities which are shown to depend on the length of the fish at first capture.

  16. Look before You Leap: Underestimating Chinese Student History, Chinese University Setting and Chinese University Steering in Sino-British HE Joint Ventures?

    ERIC Educational Resources Information Center

    Dow, Ewan G.

    2010-01-01

    This article makes the case--in three parts--that many Anglo-Chinese university collaborations (joint ventures) to date have seriously underestimated Chinese (student) history, the Chinese university setting and Chinese national governmental steering as part of the process of "glocalisation". Recent turbulence in this particular HE collaborative…

  17. Joint inference of microsatellite mutation models, population history and genealogies using transdimensional Markov Chain Monte Carlo.

    PubMed

    Wu, Chieh-Hsi; Drummond, Alexei J

    2011-05-01

    We provide a framework for Bayesian coalescent inference from microsatellite data that enables inference of population history parameters averaged over microsatellite mutation models. To achieve this we first implemented a rich family of microsatellite mutation models and related components in the software package BEAST. BEAST is a powerful tool that performs Bayesian MCMC analysis on molecular data to make coalescent and evolutionary inferences. Our implementation permits the application of existing nonparametric methods to microsatellite data. The implemented microsatellite models are based on the replication slippage mechanism and focus on three properties of microsatellite mutation: length dependency of mutation rate, mutational bias toward expansion or contraction, and number of repeat units changed in a single mutation event. We develop a new model that facilitates microsatellite model averaging and Bayesian model selection by transdimensional MCMC. With Bayesian model averaging, the posterior distributions of population history parameters are integrated across a set of microsatellite models and thus account for model uncertainty. Simulated data are used to evaluate our method in terms of accuracy and precision of estimation and also identification of the true mutation model. Finally we apply our method to a red colobus monkey data set as an example. PMID:21385725

  18. Joint Inference of Microsatellite Mutation Models, Population History and Genealogies Using Transdimensional Markov Chain Monte Carlo

    PubMed Central

    Wu, Chieh-Hsi; Drummond, Alexei J.

    2011-01-01

    We provide a framework for Bayesian coalescent inference from microsatellite data that enables inference of population history parameters averaged over microsatellite mutation models. To achieve this we first implemented a rich family of microsatellite mutation models and related components in the software package BEAST. BEAST is a powerful tool that performs Bayesian MCMC analysis on molecular data to make coalescent and evolutionary inferences. Our implementation permits the application of existing nonparametric methods to microsatellite data. The implemented microsatellite models are based on the replication slippage mechanism and focus on three properties of microsatellite mutation: length dependency of mutation rate, mutational bias toward expansion or contraction, and number of repeat units changed in a single mutation event. We develop a new model that facilitates microsatellite model averaging and Bayesian model selection by transdimensional MCMC. With Bayesian model averaging, the posterior distributions of population history parameters are integrated across a set of microsatellite models and thus account for model uncertainty. Simulated data are used to evaluate our method in terms of accuracy and precision of ? estimation and also identification of the true mutation model. Finally we apply our method to a red colobus monkey data set as an example. PMID:21385725

  19. A Demographic Approach to Selection

    Microsoft Academic Search

    Wyatt W. Anderson; Takao K. Watanabe

    1997-01-01

    The concepts of demography provide a means of combining the ecological approach to population growth with the genetical approach to natural selection. We have utilized the demographic theory of natural selection developed by Norton and Charlesworth to analyze life history schedules of births and deaths for populations of genotypes in Drosophila pseudoobscura. Our populations illustrate a stable genetic equilibrium, an

  20. A joint history of the nature of genetic variation and the nature of schizophrenia.

    PubMed

    Kendler, K S

    2015-02-01

    This essay traces the history of concepts of genetic variation and schizophrenia from Darwin and Mendel to the present. For Darwin, the important form of genetic variation for evolution is continuous in nature and small in effect. Biometricians led by Pearson agreed and developed statistical genetic approaches utilizing trait correlations in relatives. Mendel studied discontinuous traits and subsequent Mendelians, led by Bateson, assumed that important genetic variation was large in effect producing discontinuous phenotypes. Although biometricians studied 'insanity', schizophrenia genetics under Kraepelin and Rüdin utilized Mendelian approaches congruent with their anatomical-clinical disease model of dementia praecox. Fisher showed, assuming many genes of small effect, Mendelian and Biometrical models were consilient. Echoing prior conflicts, psychiatric genetics since then has utilized both biometrical models, largely in twins, and Mendelian models, based on advancing molecular techniques. In 1968, Gottesman proposed a polygenic model for schizophrenia based on a threshold version of Fisher's theory. Since then, rigorous studies of the schizophrenia spectrum suggest that genetic risk for schizophrenia is more likely continuous than categorical. The last 5 years has seen increasingly convincing evidence from genome-wide association study (GWAS) and sequencing that genetic risk for schizophrenia is largely polygenic, and congruent with Fisher's and Gottesman's models. The gap between biometrical and molecular Mendelian models for schizophrenia has largely closed. The efforts to ground a categorical biomedical model of schizophrenia in Mendelian genetics have failed. The genetic risk for schizophrenia is widely distributed in human populations so that we all carry some degree of risk. PMID:25134695

  1. PERSPECTIVE Demographic analysis of continuous-time life-history OnlineOpen: This article is available free online at www.blackwell-synergy.com

    E-print Network

    Roos, André M. de

    eigenvalue of the projection matrix [here and below I will reserve the term population growth rate to calculate the population growth rate, its sensitivity to life-history parameters and associated statistics like the stable population distribution and the reproductive value for exponentially growing

  2. Phylogeography and Demographic History of Chinese Black-Spotted Frog Populations (Pelophylax nigromaculata): Evidence for Independent Refugia Expansion and Secondary Contact

    PubMed Central

    2008-01-01

    Background Pleistocene glaciations had considerable impact on phylogeographic patterns within and among closely related species of many vertebrates. Compared to Europe and North America, research on the phylogeography of vertebrates in East Asia, particularly in China, remains limited. The black-spotted frog (Pelophylax nigromaculata) is a widespread species in East Asia. The wide distribution of this species in China makes it an ideal model for the study of palaeoclimatic effects on vertebrates in East Asia. Our previous studies of P. nigromaculata revealed significant subdivisions between the northeast China populations and populations in other regions of the mainland. In the present study, we aim to see whether the deepest splits among lineages and perhaps subsequent genealogical divisions are temporally consistent with a Pleistocene origin and whether clade geographic distributions, with insight into expansion patterns, are similarly spatially consistent with this model. Results Using 1143 nucleotides of the mitochondrial cytochrome b gene from 262 individuals sampled from 28 localities, two main clades (clade A and clade B) differing by c. 7.72% sequence divergence were defined from parsimony analyses. The corresponding timing of lineage divergence, 0.92 Mya, indicates a most likely Pleistocene split. The A clade is further subdivided into two sub-clades, A1 and A2 with 1.22% sequence divergence. Nested clade phylogeographical and population demographic analyses suggested that the current distribution of this frog species was the result of range expansion from two independent refugia during the last interglacial period. We discovered a population within which haplotype lineages A and B of P. nigromaculata coexist in the Dongliao area of China by nucleotide sequences, PCR-RFLP and ISSR (inter simple sequence repeat) patterns. The ISSR result in particular supported divergence between the mitochondrial clades A and B and implied introgressive gene flow between the two divergent lineages. Conclusion Nested clade phylogeographical and population demographic analyses indicate that the current distribution of P. nigromaculata is the result of range expansion from two independent refugia during the last interglacial period in late Pleistocene. One refugium was in east China and the lower elevations of south-western plateau. The distribution of the other mitochondrial clade is consistent with the presence of a refugium in the Korean Peninsula. The gene flow as detected by ISSR markers suggests a range expansion of the two refugia and a secondary contact between the two highly divergent lineages in the Dongliao (DL) area of northeast China. PMID:18215328

  3. Undergraduate History Degrees School of History, Archaeology and Religion, Cardiff University

    E-print Network

    Davies, Christopher

    Undergraduate History Degrees School of History, Archaeology and Religion, Cardiff University BA History BA History with Welsh History BA Integrated Degree (Archaeology & Medieval History, Ancient History & Medieval History) BA Joint Schemes (with Archaeology, Religious Studies, Languages etc.) Bsc

  4. Whole-genome sequencing reveals absence of recent gene flow and separate demographic histories for Anopheles punctulatus mosquitoes in Papua New Guinea.

    PubMed

    Logue, Kyle; Small, Scott T; Chan, Ernest R; Reimer, Lisa; Siba, Peter M; Zimmerman, Peter A; Serre, David

    2015-03-01

    Anopheles mosquitoes are the vectors of several human diseases including malaria. In many malaria endemic areas, several species of Anopheles coexist, sometimes in the form of related sibling species that are morphologically indistinguishable. Determining the size and organization of Anopheles populations, and possible ongoing gene flow among them is important for malaria control and, in particular, for monitoring the spread of insecticide resistance alleles. However, these parameters have been difficult to evaluate in most Anopheles species due to the paucity of genetic data available. Here, we assess the extent of contemporary gene flow and historical variations in population size by sequencing and de novo assembling the genomes of wild-caught mosquitoes from four species of the Anopheles punctulatus group of Papua New Guinea. Our analysis of more than 50 Mb of orthologous DNA sequences revealed no evidence of contemporary gene flow among these mosquitoes. In addition, investigation of the demography of two of the An. punctulatus species revealed distinct population histories. Overall, our analyses suggest that, despite their similarities in morphology, behaviour and ecology, contemporary sympatric populations of An. punctulatus are evolving independently. PMID:25677924

  5. History of the Balkans: Twentieth Century. Volume 2. The Joint Committee on Eastern Europe Publication Series. No. 12.

    ERIC Educational Resources Information Center

    Jelavich, Barbara

    Principal issues in the 20th century development of the Balkan Peninsula are discussed in this introductory history text. Three themes--national rivalries, great power interference, and the economic, social, and political problems of modernization--are given special emphasis. An overview of 18th and 19th century history precedes the two major…

  6. Contrasting population genetic structure among freshwater-resident and anadromous lampreys: the role of demographic history, differential dispersal and anthropogenic barriers to movement.

    PubMed

    Bracken, Fiona S A; Hoelzel, A Rus; Hume, John B; Lucas, Martyn C

    2015-03-01

    The tendency of many species to abandon migration remains a poorly understood aspect of evolutionary biology that may play an important role in promoting species radiation by both allopatric and sympatric mechanisms. Anadromy inherently offers an opportunity for the colonization of freshwater environments, and the shift from an anadromous to a wholly freshwater life history has occurred in many families of fishes. Freshwater-resident forms have arisen repeatedly among lampreys (within the Petromyzontidae and Mordaciidae), and there has been much debate as to whether anadromous lampreys, and their derived freshwater-resident analogues, constitute distinct species or are divergent ecotypes of polymorphic species. Samples of 543 European river lamprey Lampetra fluviatilis (mostly from anadromous populations) and freshwater European brook lamprey Lampetra planeri from across 18 sites, primarily in the British Isles, were investigated for 13 polymorphic microsatellite DNA loci, and 108 samples from six of these sites were sequenced for 829 bp of mitochondrial DNA (mtDNA). We found contrasting patterns of population structure for mtDNA and microsatellite DNA markers, such that low diversity and little structure were seen for all populations for mtDNA (consistent with a recent founder expansion event), while fine-scale structuring was evident for nuclear markers. Strong differentiation for microsatellite DNA loci was seen among freshwater-resident L. planeri populations and between L. fluviatilis and L. planeri in most cases, but little structure was evident among anadromous L. fluviatilis populations. We conclude that postglacial colonization founded multiple freshwater-resident populations with strong habitat fidelity and limited dispersal tendencies that became highly differentiated, a pattern that was likely intensified by anthropogenic barriers. PMID:25689694

  7. Genetic structure and demographic history of the endangered tree species Dysoxylum malabaricum (Meliaceae) in Western Ghats, India: implications for conservation in a biodiversity hotspot

    PubMed Central

    Bodare, Sofia; Tsuda, Yoshiaki; Ravikanth, Gudasalamani; Uma Shaanker, Ramanan; Lascoux, Martin

    2013-01-01

    The impact of fragmentation by human activities on genetic diversity of forest trees is an important concern in forest conservation, especially in tropical forests. Dysoxylum malabaricum (white cedar) is an economically important tree species, endemic to the Western Ghats, India, one of the world's eight most important biodiversity hotspots. As D. malabaricum is under pressure of disturbance and fragmentation together with overharvesting, conservation efforts are required in this species. In this study, range-wide genetic structure of twelve D. malabaricum populations was evaluated to assess the impact of human activities on genetic diversity and infer the species’ evolutionary history, using both nuclear and chloroplast (cp) DNA simple sequence repeats (SSR). As genetic diversity and population structure did not differ among seedling, juvenile and adult age classes, reproductive success among the old-growth trees and long distance seed dispersal by hornbills were suggested to contribute to maintain genetic diversity. The fixation index (FIS) was significantly correlated with latitude, with a higher level of inbreeding in the northern populations, possibly reflecting a more severe ecosystem disturbance in those populations. Both nuclear and cpSSRs revealed northern and southern genetic groups with some discordance of their distributions; however, they did not correlate with any of the two geographic gaps known as genetic barriers to animals. Approximate Bayesian computation-based inference from nuclear SSRs suggested that population divergence occurred before the last glacial maximum. Finally we discussed the implications of these results, in particular the presence of a clear pattern of historical genetic subdivision, on conservation policies. PMID:24223264

  8. Coordinating rooks and bishops: an institutional history of the joint army and navy board, 1903-1919

    E-print Network

    Godin, Jason Robert

    2005-11-01

    , the Board??s basic duties and responsibilities, and Joint Board actions as they impacted U.S. diplomacy and military strategy concerning the homeland and coast defense, the Caribbean and Cuba, the Panama Canal, as well as the Pacific and the Philippines...

  9. Russia's Demographic "Crisis"

    NSDL National Science Digital Library

    1996-01-01

    The Rand Organization has recently made available via the Web the full text of Russia's Demographic "Crisis." "This volume is an outgrowth of a June 5-6, 1995 conference at which a group of Russian demographers presented the results of their pioneering research on Russia's demographic 'crisis' to American colleagues from the Rand Organization, the University of California-Los Angeles, the University of Southern California, and the International Programs Center of the US Bureau of the Census." The six papers that make up the volume deal with two broad categories: "(1) fertility and family planning; and (2) issues in the area of health and mortality--health status, health care, and population aging." The scope of a Russian demographic crisis is hotly debated, as well as "the interrelations between economic reforms and demographic trends in Russia." Russia's Demographic "Crisis" should shed some light on this topic.

  10. Evolutionary shaping of demographic schedules

    PubMed Central

    Wachter, Kenneth W.; Steinsaltz, David; Evans, Steven N.

    2014-01-01

    Evolutionary processes of natural selection may be expected to leave their mark on age patterns of survival and reproduction. Demographic theory includes three main strands—mutation accumulation, stochastic vitality, and optimal life histories. This paper reviews the three strands and, concentrating on mutation accumulation, extends a mathematical result with broad implications concerning the effect of interactions between small age-specific effects of deleterious mutant alleles. Empirical data from genomic sequencing along with prospects for combining strands of theory hold hope for future progress. PMID:25024186

  11. Dancing with Demographers.

    ERIC Educational Resources Information Center

    Robertson, Heather-Jane

    2000-01-01

    Demographic projections concerning the shortage of teachers in Canada, their pay scale, the feminization of teaching, the gender gap in salaries, and teacher autonomy have often been incorrect, or correct for the wrong reasons. Instead of relying on demographic predictions, teachers should contemplate who they really want to be professionally,…

  12. Demographics: People and Markets.

    ERIC Educational Resources Information Center

    Merrick, Thomas W.; Tordella, Stephen J.

    1988-01-01

    Population shifts directly affect the bottom line, so the basics of demography are now basic to business as well. Demographics combine demographic data with socioeconomic and geographic factors to help business and other managers know the market for the goods and services they offer. This guide explains market, product, and site analyses,…

  13. Demographic Influences on Migration

    Microsoft Academic Search

    David A. Plane

    1993-01-01

    PLANE D. A. (1993) Demographic influences on migration, Reg. Studies27, 375–383. This paper explores the effects of demographic change on migration through an examination of migration rates of different age groups and cohorts over time, and the effect on total migration flows of the ageing of regional populations. Research focused on the interrelationship between age composition change and migration is

  14. The business of demographics.

    PubMed

    Russell, C

    1984-06-01

    The emergence of "demographics" in the past 15 years is a vital tool for American business research and planning. Tracing demographic trends became important for businesses when traditional consumer markets splintered with the enormous changes since the 1960s in US population growth, age structure, geographic distribution, income, education, living arrangements, and life-styles. The mass of reliable, small-area demographic data needed for market estimates and projections became available with the electronic census--public release of Census Bureau census and survey data on computer tape, beginning with the 1970 census. Census Bureau tapes as well as printed reports and microfiche are now widely accessible at low cost through summary tape processing centers designated by the bureau and its 12 regional offices and State Data Center Program. Data accessibility, plummeting computer costs, and businessess' unfamiliarity with demographics spawned the private data industry. By 1984, 70 private companies were offering demographic services to business clients--customized information repackaged from public data or drawn from proprietary data bases created from such data. Critics protest the for-profit use of public data by companies able to afford expensive mainframe computer technology. Business people defend their rights to public data as taxpaying ceitzens, but they must ensure that the data are indeed used for the public good. They must also question the quality of demographic data generated by private companies. Business' demographic expertise will improve when business schools offer training in demography, as few now do, though 40 of 88 graduate-level demographic programs now include business-oriented courses. Lower cost, easier access to business demographics is growing as more census data become available on microcomputer diskettes and through on-line linkages with large data bases--from private data companies and the Census Bureau itself. A directory of private and public demographic resources is appended, including forecasting, consulting and research services available. PMID:12313263

  15. Joint Effects of Habitat Heterogeneity and Species’ Life-History Traits on Population Dynamics in Spatially Structured Landscapes

    PubMed Central

    Ye, Xinping; Skidmore, Andrew K.; Wang, Tiejun

    2014-01-01

    Both habitat heterogeneity and species’ life-history traits play important roles in driving population dynamics, yet there is little scientific consensus around the combined effect of these two factors on populations in complex landscapes. Using a spatially explicit agent-based model, we explored how interactions between habitat spatial structure (defined here as the scale of spatial autocorrelation in habitat quality) and species life-history strategies (defined here by species environmental tolerance and movement capacity) affect population dynamics in spatially heterogeneous landscapes. We compared the responses of four hypothetical species with different life-history traits to four landscape scenarios differing in the scale of spatial autocorrelation in habitat quality. The results showed that the population size of all hypothetical species exhibited a substantial increase as the scale of spatial autocorrelation in habitat quality increased, yet the pattern of population increase was shaped by species’ movement capacity. The increasing scale of spatial autocorrelation in habitat quality promoted the resource share of individuals, but had little effect on the mean mortality rate of individuals. Species’ movement capacity also determined the proportion of individuals in high-quality cells as well as the proportion of individuals experiencing competition in response to increased spatial autocorrelation in habitat quality. Positive correlations between the resource share of individuals and the proportion of individuals experiencing competition indicate that large-scale spatial autocorrelation in habitat quality may mask the density-dependent effect on populations through increasing the resource share of individuals, especially for species with low mobility. These findings suggest that low-mobility species may be more sensitive to habitat spatial heterogeneity in spatially structured landscapes. In addition, localized movement in combination with spatial autocorrelation may increase the population size, despite increased density effects. PMID:25232739

  16. The Demographic Imperative

    ERIC Educational Resources Information Center

    Jordan, Stephen M.

    2009-01-01

    As the United States moves toward becoming a "minority-majority" country, what more can--and should--college presidents and governing boards do to provide low-income students and students of color with a pipeline to high-quality education? Ongoing discourse about shifting demographics locally and nationally must be built into institutions'…

  17. DEMOGRAPHIC AND HEALTH SURVEYS

    EPA Science Inventory

    Demographic and Health Surveys are nationally representative household surveys with large sample sizes of between 5,000 and 30,000 households, typically. DHS surveys provide data for a wide range of monitoring and impact evaluation indicators in the areas of population, health, a...

  18. Youth Demographics. Fact Sheet

    ERIC Educational Resources Information Center

    Lopez, Mark Hugo; Marcelo, Karlo Barrios

    2006-01-01

    This fact sheet compares the numbers of 18-25 year-old residents and citizens by gender, race, ethnicity, geographic distribution, marital status, military status, unemployment, educational attainment, and assesses population trends from 1968-2006. It explores such demographic characteristics of young people using data from the March Annual…

  19. Asians in New York City: A Demographic Summary.

    ERIC Educational Resources Information Center

    Steingasser, Jean; And Others

    This demographic survey provides the following information on Asian Americans: (1) states with the highest Asian American population; (2) ethnic breakdown among Asians; (3) Asian immigration history and legislation affecting it; (4) individual immigration histories of Asian Americans in New York City (New York), including the Chinese, Japanese,…

  20. Streptococcus pneumoniae serotype 6C presenting as recurrent prosthetic knee joint infection in a patient with a history of congenital asplenia and underlying autoimmune disease: a case report and literature review.

    PubMed

    Roberts, Amity L; Hewlett, Angela L; Yu, Jigui; Nahm, Moon H; Fey, Paul D; Iwen, Peter C

    2013-12-01

    This report describes a case of primary Streptococcus pneumoniae bacteremia with prosthetic joint infection caused by serotype 6C with recurrent infection in a patient with a history of congenital asplenia and underlying autoimmune disease. Isolates from the primary and recurrent infections were determined to be indistinguishable by pulsed-field gel electrophoresis. This study expands the conditions associated with recurrent invasive pneumococcal disease caused by serotype 6C. PMID:24139971

  1. KSC History Project

    NASA Technical Reports Server (NTRS)

    Dethloff, Henry C.

    2001-01-01

    The KSC History Project focuses on archival research and oral history interviews on the history of Kennedy Space Center (KSC). Related projects include the preparation of a precis and chapter outline for a proposed book-length narrative history, a bibliography of key primary and secondary resources, a brief monograph overview of the history of KSC, and a monograph on the history of safety at the Center. Finally, there is work on the development of a web page and a personal history data base associated with the oral history project. The KSC History Project has been a joint endeavor between Henry C. Dethloff and Dr. Noble Lee Snaples, Jr.

  2. Demographic Trends in Social Work over a Quarter-Century in an Increasingly Female Profession

    ERIC Educational Resources Information Center

    Schilling, Robert; Morrish, Jennifer Naranjo; Liu, Gan

    2008-01-01

    This article depicts the changing demographic portrait of social work education in the United States from 1974 through 2000 and considers the demographic shifts in the profession of social work. During this period, BSW and joint MSW-BSW programs increased from 150 to 404, MSW programs increased from 79 to 139, and social work doctoral programs…

  3. Joint Contact Stress

    PubMed Central

    Brand, Richard A

    2005-01-01

    A joint's normal mechanical history contributes to the maintenance of articular cartilage and underlying bone. Loading facilitates the flow of nutrients into cartilage and waste products away, and additionally provides the mechanical signals essential for normal cell and tissue maintenance. Deleteriously low or high contact stresses have been presumed to result in joint deterioration, and particular aspects of the mechanical environment may facilitate repair of damaged cartilage. For decades, investigators have explored static joint contact stresses (under some more or less arbitrary condition) as a surrogate of the relevant mechanical history. Contact stresses have been estimated in vitro in many joints and in a number of species, although only rarely in vivo. Despite a number of widely varying techniques (and spatial resolutions) to measure these contact stresses, reported ranges of static peak normal stresses are relatively similar from joint to joint across species, and in the range of 0.5 to 5.0 MPa. This suggests vertebrate diarthrodial joints have evolved to achieve similar mechanical design criteria. Available evidence also suggests some disorders of cartilage deterioration are associated with somewhat higher peak pressures ranging from 1-20 MPa, but overlapping the range of normal pressures. Some evidence and considerable logic suggests static contact stresses per se do not predict cartilage responses, but rather temporal aspects of the contact stress history. Static contact stresses may therefore not be a reasonable surrogate for biomechanical studies. Rather, temporal and spatial aspects of the loading history undoubtedly induce beneficial and deleterious biological responses. Finally, since all articular cartilage experiences similar stresses, the concept of a "weight-bearing" versus a "non-weight-bearing" joint seems flawed, and should be abandoned. PMID:16089079

  4. Remarriages: A Demographic Profile.

    ERIC Educational Resources Information Center

    Wilson, Barbara Foley; Clarke, Sally Cunningham

    1992-01-01

    Presents descriptive statistics for remarriages, examining marital histories of brides and grooms. Notes that in 1988, 745,000 divorced men and 748,000 divorced women remarried; for each sex, 61 percent married divorced, 35 percent married single, and 4 percent married widowed partners. Concludes that marrying young was stronger determinant of…

  5. Electronic Appendix A. Details of demographic models used in simulations. Solid boxes are shaded to indicate life history stages on the two hosts: white for the native host, Astragalus

    E-print Network

    Fordyce, James

    to indicate life history stages on the two hosts: white for the native host, Astragalus canadensis (Ac + B0, where B1 and B0 are the slope and intercept from the following regression model: y (1/AstragalusFlowerFactor, 1) = B1 * x (0, 1) + B0, y is a vector with two values (1/AstragalusFlowerFactor, 1) and x

  6. Demographic Trends: Impact on Schools

    ERIC Educational Resources Information Center

    Chong, Sylvia N. Y.; Cheah, Horn Mun

    2010-01-01

    Background: Singapore is experiencing great demographic change. These demographic trends show fewer young people and declining birth rates, greater longevity for ageing generations and an increase in the number of non-Singaporean residents. Statistics also show that more than half of the total population increase in the last decades was…

  7. Astronomy 101 Student Demographics

    NASA Astrophysics Data System (ADS)

    Deming, G. L.; Hufnagel, B.; Snyder, K. L.; Miller, E. A.

    2001-05-01

    From 1999 to 2001, the Astronomy Diagnostic Test Version 2.0 (ADT 2.0) was administered to undergraduates taking introductory astronomy for non-science majors (Astronomy 101) across the United States. A national database has been established using the results from the ADT 2.0 taken as a pretest by more than 5000 students. The 33-question multiple choice test contains 12 student background questions that can be used to create a profile of student enrollments in Astronomy 101. Students who take introductory astronomy reflect undergraduate national trends of gender, choice of major, and ethnic background. Specific questions on course expectations reveal that these students are less confident of their abilities in science than in mathematics. Mathematics background is evenly split between those who have completed only high school level topics (algebra and geometry) and those who have completed college level topics (pre-calculus and calculus). Class demographics aid in the design of effective teaching strategies for successful learning. This research was supported by the National Science Foundation through grants REC-0089239 and DGE-9714489.

  8. Utility of Intraoperative Neuromonitoring during Minimally Invasive Fusion of the Sacroiliac Joint

    PubMed Central

    Woods, Michael; Birkholz, Denise; MacBarb, Regina; Capobianco, Robyn; Woods, Adam

    2014-01-01

    Study Design. Retrospective case series. Objective. To document the clinical utility of intraoperative neuromonitoring during minimally invasive surgical sacroiliac joint fusion for patients diagnosed with sacroiliac joint dysfunction (as a direct result of sacroiliac joint disruptions or degenerative sacroiliitis) and determine stimulated electromyography thresholds reflective of favorable implant position. Summary of Background Data. Intraoperative neuromonitoring is a well-accepted adjunct to minimally invasive pedicle screw placement. The utility of intraoperative neuromonitoring during minimally invasive surgical sacroiliac joint fusion using a series of triangular, titanium porous plasma coated implants has not been evaluated. Methods. A medical chart review of consecutive patients treated with minimally invasive surgical sacroiliac joint fusion was undertaken at a single center. Baseline patient demographics and medical history, intraoperative electromyography thresholds, and perioperative adverse events were collected after obtaining IRB approval. Results. 111 implants were placed in 37 patients. Sensitivity of EMG was 80% and specificity was 97%. Intraoperative neuromonitoring potentially avoided neurologic sequelae as a result of improper positioning in 7% of implants. Conclusions. The results of this study suggest that intraoperative neuromonitoring may be a useful adjunct to minimally invasive surgical sacroiliac joint fusion in avoiding nerve injury during implant placement. PMID:25544898

  9. Hip joints

    NSDL National Science Digital Library

    Connie Raab (National Institutes of Health; )

    2006-05-17

    The human hips are an example of a ball-and-socket joint. Ball-and-socket joints have the ability to rotate in a circular motion. The joint where the arm connects to the shoulder is also a type of ball-and-socket joint.

  10. KSC History Project

    NASA Technical Reports Server (NTRS)

    Snaples, Lee

    2001-01-01

    The project is a joint endeavor between Dr. Henry Dethloff and myself and is producing a number of products related to KSC history. This report is a summary of those projects. First, there is an overview monograph covering KSC history. Second, there is a chapter outline for an eventual book-length history. Third, there is monograph on safety at KSC. Finally, there is a web page and database dedicated to the KSC oral history project.

  11. Consensus on demographic targets.

    PubMed

    Seewald, M

    1993-03-01

    In an interview, Dr. Nibhon Debavalya of the Population Division, Economic and Social commission for Asia and the Pacific (ESCAP), explained the significance of the Bali Conference as well as other population-related issues in the region. ESCAP's Population Division receives its mandate from the Committee on Population and Social Development. ESCAP's population concerns are handled under the Committee on Poverty Alleviation through Economic Growth and Social Development which will have its 1st meeting in 1993. The Population Division carries out 1) collaborative research, 2) technical assistance and advisory services 3) human resources development, and 4) population information and dissemination. In collaborative research, studies are carried out on aging of the population, consequences of population change, planning of small towns and rural human resources development, the accessibility of contraceptives and improving family planning and maternal and child health, and management information systems. The Bali Declaration on Population and Sustainable Development provides practical guidelines for developing the infrastructure for sustainable development within the region. It will be the basis of related policies and their implementation. The countries of the ESCAP region have set population goals: to reduce rates of population growth, countries should adopt strategies to attain replacement level fertility of 2.2 children per woman by the year 2010. The Declaration also encourages countries to reduce the level of infant mortality to 40 per 1000 live births or less during the same period. It states that in countries with high maternal mortality efforts should be made to reduce it by at least half by the year 2010. Major concerns also relate to the low level of male involvement in contraceptive usage, the high fertility in some countries, the issue of aging East Asia, and international migration. So far, the Asia-Pacific region is the only region that has come up with a consensus on its demographic targets. PMID:12286377

  12. Interpreting the demographic changes.

    PubMed Central

    Laslett, P

    1997-01-01

    The paper sets out the novel shape of current Western populations as to age composition, and demonstrates that their drastic ageing has been virtually instantaneous. European populations are described as uniquely old, with no precedent whatever in human history. Moreover, all the world's populations are undergoing the same process, including those of the developing societies, at an even faster pace. The general failure of people at large to recognize the process, and their persistent, entirely anachronistic attitudes to the older members of their societies, is described as cultural lag. The development now beginning of the so-called bean-pole family, vertical kin links between contemporary relatives stretching over four generations or more, with progressively fewer lateral linkages, is sketched out. The necessity of all persons having to live in the presence of their future selves is insisted on, with its corollary about having to pay personally in lowered subsistence levels for the doubled life span. The emergence of what is termed a third age is run over, and it is suggested that its presence might create a new civilization, one of the features of which might be the absence of enforced idleness due to unemployment. PMID:9460064

  13. Influence of a family history of type 2 diabetes, demographic and clinical data on carotid intima-media thickness in patients with type 1 diabetes: a cross-sectional study

    PubMed Central

    2014-01-01

    Background Intima-media thickness (IMT) of the common carotid artery is a surrogate end point of cardiovascular disease (CVD). Identifying the factors associated with a higher IMT may contribute to the identification of subjects with higher CVD risk. Our objective was to compare the common carotid IMT of type 1 diabetes patients to healthy control subjects. The secondary objective was to determine factors associated with a higher carotid IMT. Methods We conducted a cross-sectional study between March 2009 and October 2013, comprising 127 type 1 diabetes patients and 125 control subjects matched by age, gender and body mass index (BMI). Carotid IMT was measured using semi-automated edge detection software. Results Type 1 diabetes patients had a higher median IMT compared with control subjects (0.538; IQR: 0.500-0.607 vs 0.513 mm; IQR: 0.481-0.557, respectively p?=?0.001). Women with type 1 diabetes had a higher median IMT difference compared to the control group (0.537; IQR: 0.495-0.596 vs 0.502 mm; IQR: 0.472-0.543, respectively p?=?0.003) than did men with type 1 diabetes (0.547; IQR: 0.504-0.613 vs 0.528 mm; IQR: 0.492-0.575, respectively p?=?0.2). Age and diabetes duration had an additive effect on the IMT of type 1 diabetes patients. Multivariate gamma regression model analysis showed that in type 1 diabetes patients, the IMT was associated with age (Exp (?)?=?1.006, p?history of type 2 diabetes (Exp (?)?=?1.044, p?=?0.033), total cholesterol (Exp (?)?=?0.999, p?=?0.001) and creatinine clearance (Exp (?)?=?1.000, p?=?0.043). Conclusions Patients with type 1 diabetes have increased IMT, a marker of subclinical atherosclerosis. The CVD risk may be similar between men and women with type 1 diabetes, suggesting a loss of gender protection. Also, CVD risk may be higher in those with a family history of type 2 diabetes. Prospective studies are needed to confirm the predictive value of these findings and the causal effect between IMT and CVD in patients with type 1 diabetes. PMID:24886106

  14. The digital archive of the Swedish East India Company, 1731-1813: a joint project of a university library and a history department

    Microsoft Academic Search

    Margareta Benner

    2003-01-01

    The article describes a digitisation project in which Göteborg University Library, Sweden, is publishing a collection of eighteenth century manuscripts on the Internet, in collaboration with its history department. The aims of the project are to make one virtual collection of documents owned by different institutions, to give free and open access to the collection, to save heavily used documents

  15. Spontaneous and induced demographic change.

    PubMed

    Song, R L

    1991-01-01

    When some scholars from abroad analyze the role of family planning policies in developing countries in changes in the fertility rate, they differentiate 2 categories of change: one is "developmental change in the fertility rate" and the other is "induced change in the fertility rate". Professor Tian Xinyuan, of American nationality, quotes this concept in his analysis of changes in China's fertility rate, and believes that changes in China's fertility rate belong to fairly successful "induced change in fertility behavior". The author agrees with this differentiation, and feels that there is a need to incorporate this kind of differentiation in all analysis of the characteristics and mechanism of demographic change in China. Due to the inclusion of a set of intervening social variables, in fact demographic change in all countries has already evolved the 2 fundamental types of demographic change, spontaneous and induced. However, until now, the authors have not seen a systematic discussion of the differences and the relationship between these 2 types of demographic change. This paper attempts to make some theoretical investigations into the above, and firmly believes that this has definite significance for enriching theories of demographic change and guiding China's family planning practices. PMID:12343855

  16. Joint impact of physical activity and family history on the development of diabetes among urban adults in mainland china: a pooled analysis of community-based prospective cohort studies.

    PubMed

    Xu, Fei; Wang, Youfa; Ware, Robert S; Tse, Lap Ah; Wang, Zhiyong; Hong, Xin; Dunstan, David W; Owen, Neville

    2015-03-01

    To examine the joint influences of physical activity (PA) and family history (FH) of diabetes on subsequent type 2 diabetes (T2D), the authors pooled and analyzed data from 2 community-based urban adult prospective cohort studies in 2011 in Nanjing, China. Among 4550 urban participants, the 3-year cumulative incidence of T2D was 5.1%. After adjustment for potential confounders, compared with those with FH+ and insufficient PA, the adjusted odds ratio (95% confidence interval) of developing T2D was 0.42 (0.18, 0.98) for participants with sufficient PA and FH+, 0.32 (0.22, 0.46) for participants with insufficient PA and FH-, and 0.15 (0.08, 0.28) for participants with sufficient PA and FH-. Such significant graduated associations between PA/FH and risk of developing T2D were also identified in either men or women, separately. Sufficient PA and FH- may jointly reduce the risk of developing T2D in urban Chinese adults. PMID:22535551

  17. Joint Stability Characteristics of the Ankle Complex in Female Athletes With Histories of Lateral Ankle Sprain, Part II: Clinical Experience Using Arthrometric Measurement

    PubMed Central

    Kovaleski, John E.; Heitman, Robert J.; Gurchiek, Larry R.; Hollis, J. M.; Liu, Wei; IV, Albert W. Pearsall

    2014-01-01

    Context: This is part II of a 2-part series discussing stability characteristics of the ankle complex. In part I, we used a cadaver model to examine the effects of sectioning the lateral ankle ligaments on anterior and inversion motion and stiffness of the ankle complex. In part II, we wanted to build on and apply these findings to the clinical assessment of ankle-complex motion and stiffness in a group of athletes with a history of unilateral ankle sprain. Objective: To examine ankle-complex motion and stiffness in a group of athletes with reported history of lateral ankle sprain. Design: Cross-sectional study. Setting: University research laboratory. Patients or Other Participants: Twenty-five female college athletes (age = 19.4 ± 1.4 years, height = 170.2 ± 7.4 cm, mass = 67.3 ± 10.0 kg) with histories of unilateral ankle sprain. Intervention(s): All ankles underwent loading with an ankle arthrometer. Ankles were tested bilaterally. Main Outcome Measure(s): The dependent variables were anterior displacement, anterior end-range stiffness, inversion rotation, and inversion end-range stiffness. Results: Anterior displacement of the ankle complex did not differ between the uninjured and sprained ankles (P = .37), whereas ankle-complex rotation was greater for the sprained ankles (P = .03). The sprained ankles had less anterior and inversion end-range stiffness than the uninjured ankles (P < .01). Conclusions: Changes in ankle-complex laxity and end-range stiffness were detected in ankles with histories of sprain. These results indicate the presence of altered mechanical characteristics in the soft tissues of the sprained ankles. PMID:24568223

  18. Demographics in Astronomy and Astrophysics

    NASA Astrophysics Data System (ADS)

    Ulvestad, James S.

    2011-05-01

    Astronomy has been undergoing a significant demographic shift over the last several decades, as shown by data presented in the 2000 National Research Council (NRC) report "Federal Funding of Astronomical Research," and the 2010 NRC report, "New Worlds, New Horizons in Astronomy and Astrophysics." For example, the number of advertised postdoctoral positions in astronomy has increased much more rapldly than the number of faculty positions, contributing to a holding pattern of early-career astronomers in multiple postdoctoral positions. This talk will summarize some of the current demographic trends in astronomy, including information about gender and ethnic diversity, and describe some of the possible implications for the future. I thank the members of the Astro2010 Demographics Study Group, as well as numerous white-paper contributors to Astro2010, for providing data and analyses.

  19. Joint Control for Dummies: An Elaboration of Lowenkron's Model of Joint (Stimulus) Control

    ERIC Educational Resources Information Center

    Sidener, David W.

    2006-01-01

    The following paper describes Lowenkron's model of joint (stimulus) control. Joint control is described as a means of accounting for performances, especially generalized performances, for which a history of contingency control does not provide an adequate account. Examples are provided to illustrate instances in which joint control may facilitate…

  20. Industrial Revolutions and Demographic Transitions

    Microsoft Academic Search

    Michelle Connolly; Pietro F. Peretto

    1999-01-01

    We generalize the class of growth models in which the scale of the economy has level rather than growth effects, and study the implications of different demographic and research policies when both fertility choice and research effort are endogenous. The model incorporates two dimensions of technological progress: vertical (quality of goods) and horizontal (variety of goods). Both dimensions contribute to

  1. Enrollment Management: Demographic Changes. Report.

    ERIC Educational Resources Information Center

    Gribbons, Barry C.; Meuschke, Daylene M.

    The Office of Institutional Development and Technology and the Public Information Office created this report that identifies several topics of research in order to inform marketing efforts associated with enrollment management. The report is based upon demographic studies done at the College of Canyons to measure things such as changes in the size…

  2. DEMOGRAPHIC DATA FOR CENSUS 2000

    EPA Science Inventory

    This data layer represents Census 2000 demographic data derived from the PL94-171 redistricting files and SF3. Census geographic entities include blocks, blockgroups and tracts. Tiger line files are the source of the geometry representing the Census blocks. Attributes include ...

  3. 184 History History (Hist)

    E-print Network

    Dresden, Gregory

    184 History History (Hist) PROFESSORS FUTCH, GALLANIS, MERCHANT, PATCH, PORTER, SANDERS ASSOCIATE AmajorinhistoryleadingtoaBachelorofArtsdegree requires completion of 39 credits in history, including the following: 1. At least 27 credits in history courses numbered 300 or above. Fifteen of these credits must be in one

  4. The California Latino Demographic Databook

    NSDL National Science Digital Library

    Posted by the University of California-Berkeley's principal archive for social science statistics, this Website features selected data from The California Policy Research Center's publication, The California Latino Demographic Databook. The data are presented in the form of figures, tables, and demographic maps and cover such topics as the racial/ ethnic composition of California's population; percentages of Hispanics in California, county by county; Immigrants Admitted as Permanent California Residents from Selected Countries; Size of Hispanic and Non-Hispanic Households by Nativity, Period of Entry, and Citizenship; Percent of Californians in Selected Occupations by Detailed Origin; and much more. The entire databook can be ordered from the California Policy Research Center through a link on the Website.

  5. 5 CFR 841.404 - Demographic factors.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 2 2010-01-01 2010-01-01 false Demographic factors. 841.404 Section 841.404 Administrative...ADMINISTRATION Government Costs § 841.404 Demographic factors. (a) The Office of Personnel Management...

  6. The demographics of expropriation risk

    Microsoft Academic Search

    Philipp Harms; Philipp an de Meulen

    2012-01-01

    It is often argued that capital should flow from aging industrialized economies to countries with fast-growing populations.\\u000a However, institutional failures and the risk of expropriation substantially reduce developing economies’ attractiveness for\\u000a foreign investors. We analyze the influence of a country’s demographic structure on international investment inflows, using\\u000a a political economy model in which population growth potentially affects the risk of

  7. Febrile Seizure: Demographic Features and Causative Factors

    PubMed Central

    ESMAILI GOURABI, Hamed; BIDABADI, Elham; CHERAGHALIPOUR, Fatemeh; AARABI, Yasaman; SALAMAT, Fatemeh

    2012-01-01

    Objective Because of geographical and periodical variation, we prompted to determine the demographic features and causative factors for febrile seizure in Rasht. Materials & Methods In this cross-sectional study, all 6–month- to 6-year-old children with the diagnosis of febrile seizure admitted to 17 Shahrivar hospital in Rasht, from August, 2009 to August, 2010 were studied. Age, sex, family history of the disease, seizure types, body temperature upon admission and infectious causes of the fever were recorded. All statistical analysis was performed with SPSS software, version 16. Results Of the 214 children (mean age, 25.24±15.40 months), 124 were boys and 109 had a positive family history. Complex seizures were seen in 39 cases. In patients with a complex febrile seizure, 59% had the repetitive type, 20.5% had the focal type and 20.5% had more than 15 minutes duration of seizures. Most of the repetitive seizures (78.3%) occurred in patients under 2 years old; the difference between under and over 2-year-old patients was statistically significant. Study results did not show significant differences between the two genders for simple or complex seizures. The mean body temperature upon admission was 38.2±1.32?C (38.31±0.82 degrees in boys and 38.04±1.78 in girls). Upper respiratory infections were seen in most patients (74.29%). All cases of lower respiratory infections were boys. There was a statistically significant difference between boys and girls in causes of fever. Conclusion Most of the children had a positive family history and the most common causative factor was upper respiratory infection. PMID:24665278

  8. Global population structure and demographic history of the grey seal.

    PubMed

    Klimova, A; Phillips, C D; Fietz, K; Olsen, M T; Harwood, J; Amos, W; Hoffman, J I

    2014-08-01

    Although the grey seal Halichoerus grypus is one of the most familiar and intensively studied of all pinniped species, its global population structure remains to be elucidated. Little is also known about how the species as a whole may have historically responded to climate-driven changes in habitat availability and anthropogenic exploitation. We therefore analysed samples from over 1500 individuals collected from 22 colonies spanning the Western and Eastern Atlantic and the Baltic Sea regions, represented by 350 bp of the mitochondrial hypervariable region and up to nine microsatellites. Strong population structure was observed at both types of marker, and highly asymmetrical patterns of gene flow were also inferred, with the Orkney Islands being identified as a source of emigrants to other areas in the Eastern Atlantic. The Baltic and Eastern Atlantic regions were estimated to have diverged a little over 10 000 years ago, consistent with the last proposed isolation of the Baltic Sea. Approximate Bayesian computation also identified genetic signals consistent with postglacial population expansion across much of the species range, suggesting that grey seals are highly responsive to changes in habitat availability. PMID:25041117

  9. Uncovering the hidden demographic history of the USSR.

    PubMed

    Blum, A

    1991-01-01

    After the results of the 1937 census were calculated and the figures were lower than expected, Stalin arrested the census takers, altered the figures, and cancelled it. But, he did not destroy the records; they have remained in the archives of the Central National Archives for 50 years. They are now finally open to inspection thanks to glasnost. The records that are being examined are confirming what some in the West had suspected all along. Stalin wanted the 1937 census to show 170 million people, but because of famine, the actual number was more like 162 million. Stalin wanted the census to show the world that socialism was better than capitalism in terms of growth. However the forced collectivization of farms and the forced relocations of people resulted in a famine in 1933 which wiped out about 2.5 times more people over and above normal death rates. In some regions this figure is 4.5 times what is normally was. The number of people lost during WWII is also being revised in light of these new records. It appears that 26 million people died as the result of hostilities between 1941-45. This is in addition to the number normally expected to die during the same time. PMID:12284647

  10. ORIGINAL ARTICLE Life history and demographic determinants of

    E-print Network

    Bernatchez, Louis

    as exemplified by brown trout (Salmo trutta) Dimitar Serbezov,1 Per Erik Jorde,1,2 Louis Bernatchez,3 Esben use parentage analysis of a stream-living brown trout (Salmo trutta) population to quantify the effect

  11. ORIGINAL ARTICLE Life history and demographic determinants of

    E-print Network

    Bernatchez, Louis

    as exemplified by brown trout (Salmo trutta) Dimitar Serbezov,1 Per Erik Jorde,1,2 Louis Bernatchez,3 Esben of a stream-living brown trout (Salmo trutta) population to quantify the effect of between-individual variance

  12. Inferring Demographic History from a Spectrum of Shared Haplotype Lengths

    E-print Network

    Nielsen, Rasmus

    over a variety of ancient and recent time scales. Using the same technique, we analyze deeply sequenced hominids. In particular, we infer that recent African-European gene flow and ancient ghost admixture haplotype trees of mitochondria and the Y chromosome [1,2] changed our view of human origins by prompting

  13. Life History, Ecology, and Long-term Demographics of Queenfish

    Microsoft Academic Search

    Eric F. Miller; Jonathan P. Williams; Daniel J. Pondella II; Kevin T. Herbinson

    2009-01-01

    Queenfish Seriphus politus were collected at coastal power plants from San Clemente to Ventura, California. Power functions best described relations between otolith length, width, or weight and either standard length (SL) or total body weight. The length–weight relationship was described by the following equation: weight = 10 × SL. Individuals were aged to 12 years by using sagittal otolith sections.

  14. A Demographic Analysis of the Family Structure Experiences of Children in the United States

    Microsoft Academic Search

    David M. Blau; Wilbert van der Klaauw

    2007-01-01

    This paper provides a comprehensive demographic analysis of the family structure experiences of children in the U.S. Childbearing and transitions among co-residential union states defined by single, cohabiting, and married are analyzed jointly. A novel contribution is to distinguish men by their relationship to children: biological father or stepfather. This distinction is rarely made when analyzing union formation, but it

  15. Demographic Data Sources on the Internet

    Microsoft Academic Search

    Gary W. White; Peter Linberger

    1999-01-01

    Demographic data is extremely valuable for a variety of business applications, including market research, strategic planning, identifying target markets, advertising, and for use with geographic information systems. Because timely data is very important, the Internet is increasingly being used as a tool for gathering and disseminating demographic data to end-users. This paper outlines many Web sites containing demographic data. Included

  16. Association of Divorce with Socio-Demographic Covariates in China, 1955-1985

    Microsoft Academic Search

    Yi Zeng; T. Paul Schultz; Deming D. Wang; Danan Gu

    2002-01-01

    Based on a unique data set on the event history of marriage and divorce collected in the In-Depth Fertility Surveys conducted in Shanghai, Shaanxi, and Hebei in 1985 and a multivariate hazards model, this paper investigates the association between divorce risk and socio-demographic factors in China. Controlling for several other socio-demographic factors, we demonstrate that the risk of divorce for

  17. Demographic estimation methods for plants with dormancy

    USGS Publications Warehouse

    Kery, M.; Gregg, K.B.

    2004-01-01

    Demographic studies in plants appear simple because unlike animals, plants do not run away. Plant individuals can be marked with, e.g., plastic tags, but often the coordinates of an individual may be sufficient to identify it. Vascular plants in temperate latitudes have a pronounced seasonal life-cycle, so most plant demographers survey their study plots once a year often during or shortly after flowering. Life-states are pervasive in plants, hence the results of a demographic study for an individual can be summarized in a familiar encounter history, such as OVFVVF000. A zero means that an individual was not seen in a year and a letter denotes its state for years when it was seen aboveground. V and F here stand for vegetative and flowering states, respectively. Probabilities of survival and state transitions can then be obtained by mere counting. Problems arise when there is an unobservable dormant state, I.e., when plants may stay belowground for one or more growing seasons. Encounter histories such as OVFOOF000 may then occur where the meaning of zeroes becomes ambiguous. A zero can either mean a dead or a dormant plant. Various ad hoc methods in wide use among plant ecologists have made strong assumptions about when a zero should be equated to a dormant individual. These methods have never been compared among each other. In our talk and in Kery et al. (submitted), we show that these ad hoc estimators provide spurious estimates of survival and should not be used. In contrast, if detection probabilities for aboveground plants are known or can be estimated, capture-recapture (CR) models can be used to estimate probabilities of survival and state-transitions and the fraction of the population that is dormant. We have used this approach in two studies of terrestrial orchids, Cleistes bifaria (Kery et aI., submitted) and Cypripedium reginae (Kery & Gregg, submitted) in West Virginia, U.S.A. For Cleistes, our data comprised one population with a total of 620 marked ramets over 10 years, and for Cypripedium, two populations with 98 and 258 marked ramets over 11 years. We chose the ramet (= single stem or shoot) as the demographic unit of our study since there was no way distinguishing among genets (genet = genetical individual, I.e., the 'individual' that animal ecologists are mostly concerned with). This will introduce some non-independence into the data, which can nevertheless be dealt with easily by correcting variances for overdispersion. Using ramets instead of genets has the further advantage that individuals can be assigned to a state such as flowering or vegetative in an unambiguous manner. This is not possible when genets are the demographic units. In all three populations, auxiliary data was available to show that detection probability of aboveground plants was > 0.995. We fitted multistate models in program MARK by specifying three states (D, V, F), even though the dormant state D does not occur in the encounter histories. Detection probability is fixed at 1 for the vegetative (V) and the flowering state (F) and at zero for the dormant state (D). Rates of survival and of state transitions as well as slopes of covariate relationships can be estimated and LRT or the AIC machinery be used to select among models. To estimate the fraction of the population in the unobservable dormant state, the encounter histories are collapsed to 0 (plant not observed aboveground) and 1 (plant observed aboveground). The Cormack-Jolly-Seber model without constraints on detection probability is used to estimate detection probability, the complement of which is the estimated fraction of the population in the dormant state. Parameter identifiability is an important issue in multi state models. We used the Catchpole-Morgan-Freeman approach to determine which parameters are estimable in principle in our multi state models. Most of 15 tested models were indeed estimable with the notable exception of the most ge

  18. Compliant joint

    NASA Technical Reports Server (NTRS)

    Eklund, Wayne D. (inventor); Kerley, James J. (inventor)

    1990-01-01

    A compliant joint is provided for prosthetic and robotic devices which permits rotation in three different planes. The joint provides for the controlled use of cable under motion. Perpendicular outer mounting frames are joined by swaged cables that interlock at a center block. Ball bearings allow for the free rotation of the second mounting frame relative to the first mounting frame within a predetermined angular rotation that is controlled by two stop devices. The cables allow for compliance at the stops and the cables allow for compliance in six degrees of freedom enabling the duplication or simulation of the rotational movement and flexibility of a natural hip or knee joint, as well as the simulation of a joint designed for a specific robotic component for predetermined design parameters.

  19. Molecular evidence for a recent demographic expansion in the puma (Puma concolor) (Mammalia, Felidae)

    PubMed Central

    Matte, Eunice M.; Castilho, Camila S.; Miotto, Renata A.; Sana, Denis A.; Johnson, Warren E.; O’Brien, Stephen J.; de Freitas, Thales R. O.; Eizirik, Eduardo

    2013-01-01

    The puma is an iconic predator that ranges throughout the Americas, occupying diverse habitats. Previous phylogeographic analyses have revealed that it exhibits moderate levels of genetic structure across its range, with few of the classically recognized subspecies being supported as distinct demographic units. Moreover, most of the species’ molecular diversity was found to be in South America. To further investigate the phylogeographic structure and demographic history of pumas we analyzed mtDNA sequences from 186 individuals sampled throughout their range, with emphasis on South America. Our objectives were to refine the phylogeographic assessment within South America and to investigate the demographic history of pumas using a coalescent approach. Our results extend previous phylogeographic findings, reassessing the delimitation of historical population units in South America and demonstrating that this species experienced a considerable demographic expansion in the Holocene, ca. 8,000 years ago. Our analyses indicate that this expansion occurred in South America, prior to the hypothesized re-colonization of North America, which was therefore inferred to be even more recent. The estimated demographic history supports the interpretation that pumas suffered a severe demographic decline in the Late Pleistocene throughout their distribution, followed by population expansion and re-colonization of the range, initiating from South America. PMID:24385863

  20. Molecular evidence for a recent demographic expansion in the puma (Puma concolor) (Mammalia, Felidae).

    PubMed

    Matte, Eunice M; Castilho, Camila S; Miotto, Renata A; Sana, Denis A; Johnson, Warren E; O'Brien, Stephen J; de Freitas, Thales R O; Eizirik, Eduardo

    2013-12-01

    The puma is an iconic predator that ranges throughout the Americas, occupying diverse habitats. Previous phylogeographic analyses have revealed that it exhibits moderate levels of genetic structure across its range, with few of the classically recognized subspecies being supported as distinct demographic units. Moreover, most of the species' molecular diversity was found to be in South America. To further investigate the phylogeographic structure and demographic history of pumas we analyzed mtDNA sequences from 186 individuals sampled throughout their range, with emphasis on South America. Our objectives were to refine the phylogeographic assessment within South America and to investigate the demographic history of pumas using a coalescent approach. Our results extend previous phylogeographic findings, reassessing the delimitation of historical population units in South America and demonstrating that this species experienced a considerable demographic expansion in the Holocene, ca. 8,000 years ago. Our analyses indicate that this expansion occurred in South America, prior to the hypothesized re-colonization of North America, which was therefore inferred to be even more recent. The estimated demographic history supports the interpretation that pumas suffered a severe demographic decline in the Late Pleistocene throughout their distribution, followed by population expansion and re-colonization of the range, initiating from South America. PMID:24385863

  1. Is joint hypermobility important in prepubertal children?

    Microsoft Academic Search

    Pelin Yazgan; ?clal Geyikli; Dost Zeyrek; Lutfu Baktiroglu; Mehmet Ali Kurcer

    2008-01-01

    The purpose of this study was to investigate serum prolidase activity and its relationship with collagen metabolism and joint\\u000a hypermobility, and to determine the prevalence and characteristics of joint hypermobility in prepubertal children. Serum prolidase\\u000a activity was measured spectrophotometrically. Joint hypermobility was defined using Beighton criteria. The children underwent\\u000a complete history and physical examination. Serum levels of prolidase were lower

  2. LAW, HISTORY, &LAW, HISTORY, &LAW, HISTORY, & CULTURECULTURECULTURE

    E-print Network

    Rohs, Remo

    LAW, HISTORY, &LAW, HISTORY, &LAW, HISTORY, & CULTURECULTURECULTURE The Law, History, and Culture specific legal issues through a humanistic lens. Opportunities for Students Phi Alpha Theta: This history honor society seeks to bring students, teachers, and writers of history together for intellectual

  3. Joint chondrolysis.

    PubMed

    Provencher, Matthew T; Navaie, Maryam; Solomon, Daniel J; Smith, Jessica C; Romeo, Anthony A; Cole, Brian J

    2011-11-01

    Although the disease was first described in the hip, reports of chondrolysis in nearly all diarthrodial joints have since emerged with considerable variations in the literature.Despite speculation among clinicians and researchers about the implicit causal pathways and etiologic contributors associated with chondrolysis, definitive answers remain elusive.The term chondrolysis has been applied to varied levels of joint cartilage destruction from focal chondral defects to diffuse cartilage loss, revealing a lack of consistency in the application of diagnostic criteria to guide differential disease classification.Differentiating between the various potential etiologies associated with chondrolysis provides opportunities for the prevention of the disease. PMID:22048100

  4. [Family planning and demographic regression].

    PubMed

    Ferrer Regales, M

    1979-06-01

    The problem of demographic explosion must be reexamined in the light of what has happened during the last 15-20 years in all industrialized countries, which have all experienced a sharp decrease in fertility rates due to the introduction of modern contraceptive technics, decreased mortality, and the possibility of easily obtaining induced legal abortion. Countries such as West Germany, England, Scotland, and Luxembourg have already reached zero population growth; countries such as Austria, Norway, Finland, Sweden have a growth rate of merely 0.2%. In most western countries average parity is 1.8 children per woman, when 2.18 children are needed to guarantee replacement. The sharpest decrease in fertility rates took place in West Germany and in France; should the tendency in those countries continue West Germany population would go from 60 million inhabitants to 39 million in 2030, and France would go from 53 million to 16 million. Demographic aging is another phenomenon related to fertility decrease; in 1977 in the United States 11% of the population was already over 65. Results of fertility decrease have been so sharp and so rapid that many Eastern European countries have already introduced incentives to reverse the trend, and/or to make abortion more difficult to obtain. This policy of incentives to encourage population growth has reached West Germany where since 1978 very young couples are given monetary help. Beside contraceptive availability population decrease has been fostered by the enormous increase in the rate of divorces and by the very liberal abortion laws. A large number of today's births are illegitimate, due mainly to the practice of trial marriages, without intention of real marriage, among adolescents. PMID:95331

  5. The Importance of Demographic Data in Astronomy

    NASA Astrophysics Data System (ADS)

    Elmegreen, Debra M.

    2014-01-01

    The most effective astronomical workforce will be one that comprises a diverse and inclusive community. The “New Worlds, New Horizons in Astronomy and Astrophysics” Decadal Survey, with input from its Infrastructure Study Group on Demographics, provided an overview of recent demographic trends. Demographics in astronomy have undergone significant changes over the past two generations in several, but not all, categories. Maintaining records of demographics regarding age, gender, and minority status, as well as trends by discipline and career choices, is vital in planning for the future training and employment of astronomers.

  6. Hip joint replacement

    MedlinePLUS

    ... made joint. The artificial joint is called a prosthesis . ... thromboembolic disease in patients undergoing elective hip and ... joint arthroplasties: current concepts of patient outcomes after ...

  7. The prevalence of joint hypermobility among high school students

    Microsoft Academic Search

    Ümit Seçkin; Birkan Sonel Tur; Özlem Y?lmaz; ?lker Ya?c?; Hatice Bodur; Tansu Aras?l

    2005-01-01

    Objective: The aim of this study was to deter- mine the prevalence of joint hypermobility among high school students and to define the characteristics of pa- tients with joint hypermobility. Methods: The students underwent complete history and physical examination. In order to designate marfanoid habitus, body weight, height, and span\\/height and upper\\/lower segment ratios were recorded. The degree of joint

  8. Investigation of the demographic and selective forces shaping the nucleotide diversity of genes involved in nod factor signaling in Medicago truncatula.

    PubMed

    De Mita, Stéphane; Ronfort, Joëlle; McKhann, Heather I; Poncet, Charles; El Malki, Redouane; Bataillon, Thomas

    2007-12-01

    Symbiotic nitrogen-fixing rhizobia are able to trigger root deformation in their Fabaceae host plants, allowing their intracellular accommodation. They do so by delivering molecules called Nod factors. We analyzed the patterns of nucleotide polymorphism of five genes controlling early Nod factor perception and signaling in the Fabaceae Medicago truncatula to understand the selective forces shaping the evolution of these genes. We used 30 M. truncatula genotypes sampled in a genetically homogeneous region of the species distribution range. We first sequenced 24 independent loci and detected a genomewide departure from the hypothesis of neutrality and demographic equilibrium that suggests a population expansion. These data were used to estimate parameters of a simple demographic model incorporating population expansion. The selective neutrality of genes controlling Nod factor perception was then examined using a combination of two complementary neutrality tests, Tajima's D and Fay and Wu's standardized H. The joint distribution of D and H expected under neutrality was obtained under the fitted population expansion model. Only the gene DMI1, which is expected to regulate the downstream signal, shows a pattern consistent with a putative selective event. In contrast, the receptor-encoding genes NFP and NORK show no significant signatures of selection. Among the genes that we analyzed, only DMI1 should be viewed as a candidate for adaptation in the recent history of M. truncatula. PMID:18073426

  9. A study of temporomandibular joint sounds. Part 2. Acoustic characteristics of joint sounds.

    PubMed

    Motoyoshi, M; Matsumoto, Y; Ohnuma, M; Arimoto, M; Takahashi, K; Namura, S

    1995-03-01

    In an attempt to gain a better understanding of temporomandibular joint (TMJ) sounds, we recorded joint sounds from 14 non-orthodontically treated dental students, analyzed the acoustic characteristics of the TMJ sounds, and correlated the sound characteristics with axiographic features, morphologic observations of X-ray images and clinical history. The group with a low peak frequency (< 500 Hz) of the opening click had a shorter history of subjective joint sound, a longer distance between the opening and closing curves, and a low rate of TMJ transformation. For the closing click, the history of subjective joint sounds tended to be longer when the duration of the wave was short. Acoustic analysis of TMJ sounds could be an aid to the differential diagnosis of temporomandibular disorders, although it is difficult to deduce the clinical history and internal deformities of the TMJ based solely on acoustic characteristics. PMID:7782822

  10. Prevalence and demographic distribution of adult survivors of child abuse in Japan.

    PubMed

    Tsuboi, Satoshi; Yoshida, Honami; Ae, Ryusuke; Kojo, Takao; Nakamura, Yosikazu; Kitamura, Kunio

    2015-03-01

    A cross-sectional study was conducted with a national epidemiological survey to investigate the prevalence and demographic distribution of adult survivors of child abuse in Japan. A self-administered questionnaire was used to measure the history of child abuse and the demographic characteristics. The participants reported the following 4 types of child abuse: physical abuse (3%), sexual abuse (0.6%), neglect (0.8%), and psychological abuse (4%). Significant unequal distribution of child abuse was found to be associated with sex, living region, marital status, job status, and educational status. We determined the prevalence of adult survivors of child abuse in Japan and found that their demographic characteristics were unequally distributed. Policy makers and public health providers should take these demographic disparities into account in considering effective public health interventions for survivors of child abuse. PMID:23687257

  11. Darwinian and demographic forces affecting human protein coding genes

    PubMed Central

    Nielsen, Rasmus; Hubisz, Melissa J.; Hellmann, Ines; Torgerson, Dara; Andrés, Aida M.; Albrechtsen, Anders; Gutenkunst, Ryan; Adams, Mark D.; Cargill, Michele; Boyko, Adam; Indap, Amit; Bustamante, Carlos D.; Clark, Andrew G.

    2009-01-01

    Past demographic changes can produce distortions in patterns of genetic variation that can mimic the appearance of natural selection unless the demographic effects are explicitly removed. Here we fit a detailed model of human demography that incorporates divergence, migration, admixture, and changes in population size to directly sequenced data from 13,400 protein coding genes from 20 European-American and 19 African-American individuals. Based on this demographic model, we use several new and established statistical methods for identifying genes with extreme patterns of polymorphism likely to be caused by Darwinian selection, providing the first genome-wide analysis of allele frequency distributions in humans based on directly sequenced data. The tests are based on observations of excesses of high frequency–derived alleles, excesses of low frequency–derived alleles, and excesses of differences in allele frequencies between populations. We detect numerous new genes with strong evidence of selection, including a number of genes related to psychiatric and other diseases. We also show that microRNA controlled genes evolve under extremely high constraints and are more likely to undergo negative selection than other genes. Furthermore, we show that genes involved in muscle development have been subject to positive selection during recent human history. In accordance with previous studies, we find evidence for negative selection against mutations in genes associated with Mendelian disease and positive selection acting on genes associated with several complex diseases. PMID:19279335

  12. Changing School Demographics: The New Baby Boom.

    ERIC Educational Resources Information Center

    Lake, Sara

    This paper addresses the demographic and socioeconomic effects on schools of the "new baby boom," consisting of school-age children of the original "baby boomers." The effects of this second-generation demographic trend include a higher proportion of minority students (since the decline in marriage and birth rates among baby boomers reaching…

  13. Lifelong Learning and Demographics: A Japanese Perspective

    ERIC Educational Resources Information Center

    Ogawa, Seiko

    2005-01-01

    This paper explores the social dimension of lifelong learning from the perspective of demographics, with particular focus on the issue of the birth of fewer children, which has become one of the most important current social issues in Japanese society. When considering the relationship between lifelong learning and demographics, the issues arising…

  14. Demographic uncertainty in ecological risk assessments

    Microsoft Academic Search

    Guiming Wang; W. Daniel Edge; Jerry O Wolff

    2001-01-01

    We built a Ricker's model incorporating demographic stochasticity to simulate the effects of demographic uncertainty on responses of gray-tailed vole (Microtus canicaudus) populations to pesticide applications. We constructed models with mark-recapture data collected from populations in 1998 and 1999. We ran 30 simulations of a single pesticide application for small (?30 voles), medium (?50 voles), and large (?100 voles) population

  15. Life Potential as a Basic Demographic Indicator

    ERIC Educational Resources Information Center

    Goerlich, Francisco J.; Soler, Angel

    2013-01-01

    This paper proposes an indicator that integrates life expectancy with the demographic structure of the population for a given society. By doing this, we have a simple indicator of mortality and aging combined, which could be very useful for developed societies. As is widely known, life expectancy at birth is independent of the demographic

  16. Inferring Demographic Attributes of Anonymous Internet Users

    Microsoft Academic Search

    Dan Murray; Kevan Durrell

    2000-01-01

    Today it is quite common for web page content to include an advertisement. Since advertisers often want to target their message to people with certain demographic attributes, the anonymity of Internet users poses a special problem for them. The purpose of the present research is to find an effective way to infer demographic information (e.g. gender, age or income) about

  17. Demographic and Economic Changes and Postsecondary Education.

    ERIC Educational Resources Information Center

    Charner, Ivan

    The interaction of demographic and economic shifts has led to, and will continue to effect, changes in the postsecondary education system and institutions. Demographic shifts include aging of the population, more women in the paid labor force, and increased numbers of minorities. Economic shifts include the growth of the information sector,…

  18. Joint assembly

    NASA Technical Reports Server (NTRS)

    Wilson, Andrew (Inventor); Punnoose, Andrew (Inventor); Strausser, Katherine (Inventor); Parikh, Neil (Inventor)

    2010-01-01

    A joint assembly is provided which includes a drive assembly and a swivel mechanism. The drive assembly features a motor operatively associated with a plurality of drive shafts for driving auxiliary elements, and a plurality of swivel shafts for pivoting the drive assembly. The swivel mechanism engages the swivel shafts and has a fixable element that may be attached to a foundation. The swivel mechanism is adapted to cooperate with the swivel shafts to pivot the drive assembly with at least two degrees of freedom relative to the foundation. The joint assembly allows for all components to remain encased in a tight, compact, and sealed package, making it ideal for space, exploratory, and commercial applications.

  19. The Epidemiology and Demographics of Hip Dysplasia

    PubMed Central

    Loder, Randall T.; Skopelja, Elaine N.

    2011-01-01

    The etiology of developmental dysplasia of the hip (DDH) is unknown. There are many insights, however, from epidemiologic/demographic information. A systematic medical literature review regarding DDH was performed. There is a predominance of left-sided (64.0%) and unilateral disease (63.4%). The incidence per 1000 live births ranges from 0.06 in Africans in Africa to 76.1 in Native Americans. There is significant variability in incidence within each racial group by geographic location. The incidence of clinical neonatal hip instability at birth ranges from 0.4 in Africans to 61.7 in Polish Caucasians. Predictors of DDH are breech presentation, positive family history, and gender (female). Children born premature, with low birth weights, or to multifetal pregnancies are somewhat protected from DDH. Certain HLA A, B, and D types demonstrate an increase in DDH. Chromosome 17q21 is strongly associated with DDH. Ligamentous laxity and abnormalities in collagen metabolism, estrogen metabolism, and pregnancy-associated pelvic instability are well-described associations with DDH. Many studies demonstrate an increase of DDH in the winter, both in the northern and southern hemispheres. Swaddling is strongly associated with DDH. Amniocentesis, premature labor, and massive radiation exposure may increase the risk of DDH. Associated conditions are congenital muscular torticollis and congenital foot deformities. The opposite hip is frequently abnormal when using rigorous radiographic assessments. The role of acetabular dysplasia and adult hip osteoarthritis is complex. Archeological studies demonstrate that the epidemiology of DDH may be changing. PMID:24977057

  20. Demographic Processes Underlying Subtle Patterns of Population Structure in the Scalloped Hammerhead

    E-print Network

    Klimley, A. Peter

    to over-harvesting [4], [5]. Among the most affected and ecologically important species are sharks [6], [7 Hammerhead Shark, Sphyrna lewini Holly A. Nance1 *, Peter Klimley2 , Felipe Galva´n-Magan~ a3 , Jimmy Marti scalloped hammerhead shark, Sphyrna lewini. Therefore, we have reconstructed the demographic history of S

  1. Demographic analysis as an aid in shark stock assessment and management

    Microsoft Academic Search

    Enric Cortés

    1998-01-01

    The use of demographic analyses incorporating life history information on validated age and growth, reproduction, and natural mortality is proposed to gain insight into the population dynamics of sharks under a variety of scenarios and to assess their vulnerability to varying exploitation rates. This approach provides a useful framework for comparison with other currently used methods of assessment, especially those

  2. The Politics of Maintaining Diversity Policies in Demographically Changing Urban-Suburban School Districts

    ERIC Educational Resources Information Center

    Diem, Sarah; Frankenberg, Erica; Cleary, Colleen; Ali, Nazneen

    2014-01-01

    This study focuses on how the demographic change occurring within two county-wide school districts and communities in the South, including the creation of suburban enclaves alongside central cities overwhelmingly made up of low-income students of color, influences community support for diversity policies within two school districts with a history

  3. Demographic Processes Underlying Subtle Patterns of Population Structure in the Scalloped Hammerhead Shark, Sphyrna lewini

    Microsoft Academic Search

    Holly A. Nance; Peter Klimley; Felipe Galván-Magańa; Jimmy Martínez-Ortíz; Peter B. Marko

    2011-01-01

    Genetic diversity (?), effective population size (Ne), and contemporary levels of gene flow are important parameters to estimate for species of conservation concern, such as the globally endangered scalloped hammerhead shark, Sphyrna lewini. Therefore, we have reconstructed the demographic history of S. lewini across its Eastern Pacific (EP) range by applying classical and coalescent population genetic methods to a combination

  4. GENETIC ANALYSIS OF A POPULATION OF TRIBOLIUM. VI. POLYMORPHISM AND DEMOGRAPHIC EQUILIBRIUM

    Microsoft Academic Search

    A. M. MOFFAl; R. F. COSTANTINO

    Demographic and genetic data of continuously growing populations of Tribolium casianeum initiated with identical age structures but with different frequencies of the unsaturated fatty acid-sensitive allele were collected for 68 weeks.-The life history data provided the following insights: Genotypic dif- ferences for total number of offspring were due primarily to larval viability. The total lifetime offspring production of the genotypes

  5. Prehypertension: demographics, pathophysiology, and treatment.

    PubMed

    Izzo, Joseph L

    2007-08-01

    The term prehypertension, which first appeared in the Seventh Report of the Joint National Committee (JNC 7) in 2003, has sparked controversy in the field of hypertension. Systolic blood pressure (BP) rises with age in industrialized societies, but an individual's rate of rise of systolic BP and the age at which BP crosses the arbitrary threshold of hypertension depends on prior BP levels (hence "prehypertension"). Obesity, another major factor in prehypertension, activates neurohumoral systems (renin-angiotensin and sympathetic nervous) and contributes to age-related BP increases. The JNC 7 recommendation for prehypertension management with optimal weight control (largely through diet and exercise) remains the mainstay, especially in the elderly. The Trial of Prevention of Hypertension demonstrated that angiotensin receptor blockade (ARB) retards age-related BP increases in prehypertensive patients. Associated elevated risk conditions (prediabetes, hypercholesterolemia, microalbuminuria) may justify early use of ARB therapy (in men and in women without childbearing potential) if weight control fails. PMID:17686375

  6. Demographic, criminal, and psychiatric factors related to inmate suicide.

    PubMed

    Blaauw, Eric; Kerkhof, Ad J F M; Hayes, Lindsay M

    2005-02-01

    A review of 19 studies suggests that it may be feasible to identify prisoners with suicide risk on the basis of demographic, psychiatric, and criminal characteristics. The present study aimed to identify combinations of characteristics that are capable of identifying potential suicide victims. Characteristics of 95 suicide victims in the Dutch prison system were compared with those of a random sample of 247 inmates in ten jails. Combinations of indicators for suicide risk were also tested for their capability of identifying 209 suicides in U.S. jails and 279 prison suicides in England and Wales. A combination of six characteristics (age 40+, homelessness, history of psychiatric care, history of drug abuse, one prior incarceration, violent offence) was capable of correctly classifying 82% of the Dutch suicide victims (82% specificity). Less powerful combinations correctly classified 53% of the U.S. suicides and 47% of the U.K. suicides. It is concluded that a set of demographic and criminal characteristics and indicators of psychiatric problems is useful for the identification of suicide risk in jails and prisons. PMID:15843324

  7. Severe hyperkalaemia: demographics and outcome

    PubMed Central

    Phillips, B.M.; Milner, S.; Zouwail, S.; Roberts, G.; Cowan, M.; Riley, S.G.; Phillips, A.O.

    2014-01-01

    Background Few studies have evaluated the prevalence of severe hyperkalaemia in unselected patient populations. We identified all episodes of severe hyperkalaemia occurring in 1 year, and described patient demographics, clinical response and outcome. We also assessed junior doctor knowledge of its causes and significance. Materials and methods A retrospective interrogation of the database of the regional biochemical laboratory identified all episodes of severe hyperkalaemia (K? 6.5 mmol/L) occurring in 2011. The understanding of trainee doctors of the importance, causes and treatment of severe hyperkalaemia was assessed by structured questionnaire. Results Severe hyperkalaemia was recorded in 433 samples (365 patients) giving a prevalence of 0.11%. Thirty-six per cent of episodes occurred in patients under the care of a nephrologist, who were significantly younger than those not under the care of a nephrologist. In the nephrology cohort, 86% occurred in patients with chronic kidney disease (CKD), the majority of which had CKD Stage 5. In the non-nephrology cohort, only 65% occurred in the context of CKD, which was equally distributed between Stages 3 and 5 CKD. In both patient groups, roughly 50% of episodes occurred in association with acute kidney injury (AKI). Acute mortality (death within 48 h of documented severe hyperkalaemia) was higher in the non-nephrology compared with the nephrology cohort. Time to repeat serum potassium was influenced by the clinical setting with shorter time to repeat for acute care compared with ward settings. Assessment of trainee doctor's knowledge suggested significant deficiencies in relation to severe hyperkalaemia. Conclusions The prevalence of severe hyperkalaemia was low and occurred predominantly in the context of CKD and/or AKI. The majority of episodes occurred in patients not under the care of a nephrologist. Variability in time to repeat serum potassium levels suggested deficiencies in care, and assessment of trainee doctor’s knowledge suggests the need for further educational initiatives to highlight its importance. PMID:25852860

  8. [Demographic transition or revolution? The weaknesses and implications of the demographic transition theory. Part 1: the origins].

    PubMed

    Bourcier De Carbon, P

    1998-01-01

    The work of Adolphe Landry is reviewed in relation to development of demographic transition theory. Landry was appointed administrator in 1912 of the National Alliance Against Depopulation and remained active in it his whole life. He also helped create family allowance programs in France. As early as 1909, Landry described three different population regimes. In the "primitive" regime, which characterized all nonhuman life and human life during most of history, the population was adjusted to available subsistence by mortality. In the "intermediate" phase, restrictions on marriage and control of reproduction outside marriage maintained the population at a level below the maximum supportable. In the "contemporary" regime, the universal practice of contraception and abortion could lead to very low levels of fertility. The spread of contraception and low fertility appeared to Landry a true demographic revolution. He attributed the acceptance of contraception to a change in the common aspirations of human beings regarding their conditions, a desire for improved material well-being and social advancement, and an increased spirit of rationality and even calculation in their behavior. Landry believed that the contemporary regime, unlike the preceding two, had no mechanism implying equilibrium. The demographic revolution freed fertility from social determinants and linked it more closely to individual interests. Landry expected the contemporary regime to spread throughout the entire world, with many areas still in the primitive phase passing directly to the contemporary. He was concerned with the effects of demographic aging, and he deplored birth control propaganda that claimed it as a cure for unemployment and for overpopulation in the poor Asian countries. The birth control movements in England and the US were successful in bringing the two countries into the contemporary regime. A number of organizations such as the Population Association of America and the Office of Population Research at Princeton were favorable toward the spread of birth control through the rest of the world. PMID:12294439

  9. Inferring the strength of selection in Drosophila under complex demographic models.

    PubMed

    González, Josefa; Macpherson, J Michael; Messer, Philipp W; Petrov, Dmitri A

    2009-03-01

    Transposable elements (TEs) constitute a substantial fraction of the genomes of many species, and it is thus important to understand their population dynamics. The strength of natural selection against TEs is a key parameter in understanding these dynamics. In principle, the strength of selection can be inferred from the frequencies of a sample of TEs. However, complicated demographic histories, such as found in Drosophila melanogaster, could lead to a substantial distortion of the TE frequency distribution compared with that expected for a panmictic, constant-sized population. The current methodology for the estimation of selection intensity acting against TEs does not take into account demographic history and might generate erroneous estimates especially for TE families under weak selection. Here, we develop a flexible maximum likelihood methodology that explicitly accounts both for demographic history and for the ascertainment biases of identifying TEs. We apply this method to the newly generated frequency data of the BS family of non-long terminal repeat retrotransposons in D. melanogaster in concert with two recent models of the demographic history of the species to infer the intensity of selection against this family. We find the estimate to differ substantially compared with a prior estimate that was made assuming a model of constant population size. Further, we find there to be relatively little information about selection intensity present in the derived non-African frequency data and that the ancestral African subpopulation is much more informative in this respect. These findings highlight the importance of accounting for demographic history and bear on study design for the inference of selection coefficients generally. PMID:19033258

  10. Open versus minimally invasive sacroiliac joint fusion: a multi-center comparison of perioperative measures and clinical outcomes

    PubMed Central

    2013-01-01

    Background Sacroiliac (SI) joint pain is an under diagnosed source of low back pain due in part to lack of visible pathology on radiographs and symptoms mimicking other back-related disorders. Open SI joint fusion has been performed since the 1920s. This technique has fallen out of favor with the introduction of minimally invasive options. To date there has been no direct comparison between open and MIS SI joint fusion. Methods We conducted a multi-center, retrospective comparative cohort study of patients who underwent SI joint fusion using either an open surgical (OS) technique using a combination of screws and cages or a minimally invasive surgical (MIS) technique with a series of titanium plasma spray (TPS) coated triangular implants. Operative measures including surgical operating time, length of hospitalization and estimated blood loss (EBL) were collected along with demographics and medical history, surgical complications, and 12- and 24-month pain scores. Improvements in pain were compared after matching for age and gender and controlling for a history of lumbar spine fusion using repeated measures analysis of variance. Results Data were available for 263 patients treated by 7 surgeons; 149 patients treated with OS and 114 treated with MIS SI joint fusion. Compared to OS patients, MIS patients were on average 10 years older (mean age 57 vs. 46) and 69% of all patients were female. MIS operative measures of EBL, operating time and length of hospitalization were significantly lower than open surgery (p?history of prior lumbar spinal fusion, postoperative pain scores were on average 3.0 points (95% CI 2.1 – 4.0) lower in MIS vs. OS (rANOVA p?joint fusion showed postoperative improvements in pain score. Compared to OS patients, patients who underwent MIS SI joint fusion had significantly greater pain relief and more favorable perioperative surgical measures. PMID:24172188

  11. Teaching Family History: Papers from Old Sturbridge Village.

    ERIC Educational Resources Information Center

    Journal of Family History, 1981

    1981-01-01

    Essays in this special issue of the "Journal of Family History" focus on the teaching of family history by using artifacts. The articles were written by the staff at Old Sturbridge Village (OSV). The first article discusses how family history is taught at OSV. Students study a real family using demographic information and artifacts such as…

  12. Demographic concepts and research pertaining to the study of wild primate populations.

    PubMed

    Lawler, Richard R

    2011-01-01

    Demography is the study of individuals as members of a population. The dynamics of a population are determined by collectively analyzing individual schedules of survival, growth, and reproduction. Together, these schedules are known as the vital rates of the population. The vital rates, along with dispersal, contribute to population structure, which refers to how the population is organized by age, sex, density, and social groups. I briefly review the history of anthropological demography as it pertains to wild primates and then I discuss basic demographic concepts and approaches for studying wild primate populations. I then turn to demographic studies of wild primate demography. Primates are generally characterized by high adult survival probabilities relative to survival at other age/stage classes and most primate populations have population growth rates near equilibrium. Changes in adult survival have the greatest impact on population growth rate (i.e., fitness) relative to other demographic traits such as juvenile/yearling survival or age at first reproduction. I discuss how these demographic patterns, and others, connect to topics and issues in behavioral ecology, life history theory, population genetics, and conservation biology. These connections help reaffirm the fact that the vital rates are both targets and agents of evolutionary change. In this regard, demographic studies of wild primates provide a critical link between the proximate socioecological processes that operate in a species and the long-term phylogenetic patterns that characterize a species. PMID:21997178

  13. CENTRACT BOUNDARIES AND DEMOGRAPHIC DATABASE AND CVOVERAGE

    EPA Science Inventory

    This coverage contains Census Tract boundaries and associated demographic data. "Census tracts are small, relatively permanent statistical subdivisions of a county. Census tracts are delineated for all metropolitan areas (MAs) and other densely populated counties by local c...

  14. Demographic Change and Conflict in Contemporary Africa

    Microsoft Academic Search

    Elliott D. Green

    2009-01-01

    Sub-Saharan Africa has gone from having a very low population density and negative population growth in the 19th century to an extremely high population growth today. While some political demographers have linked the continent\\

  15. The Demographic Transition Influences Variance in Fitness and Selection on Height and BMI in Rural Gambia

    PubMed Central

    Courtiol, Alexandre; Rickard, Ian J.; Lummaa, Virpi; Prentice, Andrew M.; Fulford, Anthony J.C.; Stearns, Stephen C.

    2013-01-01

    Summary Recent human history is marked by demographic transitions characterized by declines in mortality and fertility [1]. By influencing the variance in those fitness components, demographic transitions can affect selection on other traits [2]. Parallel to changes in selection triggered by demography per se, relationships between fitness and anthropometric traits are also expected to change due to modification of the environment. Here we explore for the first time these two main evolutionary consequences of demographic transitions using a unique data set containing survival, fertility, and anthropometric data for thousands of women in rural Gambia from 1956–2010 [3]. We show how the demographic transition influenced directional selection on height and body mass index (BMI). We observed a change in selection for both traits mediated by variation in fertility: selection initially favored short females with high BMI values but shifted across the demographic transition to favor tall females with low BMI values. We demonstrate that these differences resulted both from changes in fitness variance that shape the strength of selection and from shifts in selective pressures triggered by environmental changes. These results suggest that demographic and environmental trends encountered by current human populations worldwide are likely to modify, but not stop, natural selection in humans. PMID:23623548

  16. Population History and Natural Selection Shape Patterns of Genetic Variation in 132 Genes

    Microsoft Academic Search

    Joshua M. Akey; Michael A. Eberle; Mark J. Rieder; Christopher S. Carlson; Mark D. Shriver; Deborah A. Nickerson; Leonid Kruglyak

    2004-01-01

    Identifying regions of the human genome that have been targets of natural selection will provide important insights into human evolutionary history and may facilitate the identification of complex disease genes. Although the signature that natural selection imparts on DNA sequence variation is difficult to disentangle from the effects of neutral processes such as population demographic history, selective and demographic forces

  17. Australians' organic food beliefs, demographics and values

    Microsoft Academic Search

    Emma Lea; Tony Worsley

    2005-01-01

    Purpose – To examine consumers' beliefs about organic foods and their relationship with socio-demographics and self-transcendence (universal, benevolence) personal values. Design\\/methodology\\/approach – A random questionnaire-based mail survey of 500 Australian (Victorian) adults (58 per cent response) was used. The questionnaire included items on organic food beliefs, the importance of self-transcendence values as guiding principles in life, and socio-demographics. Statistical analyses

  18. Changing demographics of the American population.

    PubMed

    Halaweish, Ihab; Alam, Hasan B

    2015-02-01

    Since 1950, the United States has been in the midst of a profound demographic change: the rapid aging of the population. The baby boom generation began turning 65 in 2011 and is now driving growth at the older ages of the population. This article highlights geriatric demographic changes and illustrates how these and future trends will have wide ranging implications for the US health care system. PMID:25459538

  19. Developments of joint elements and solution algorithms for dynamic analysis of jointed structures

    NASA Astrophysics Data System (ADS)

    Yue, Xue

    2002-09-01

    This thesis presents an approach for constructing predictive models of structures with joints/interfaces which can not be modeled by conventional finite elements. The proposed approach partitions the whole jointed structure into linear substructures and nonlinear joint components. It is assumed that the linear substructures can be accurately modeled by finite elements. It is also assumed that joints/interfaces are the only sources of system nonlinearities. A class of nonlinear discrete joint elements designed to model representative types of joints/interfaces are developed in this thesis. The constitutive relation incorporated into joint elements characterizes the incremental joint nonlinear force in terms of the incremental interface relative displacement and the history of the force itself. The joint model is validated by correlating with the classical quasi-static solution of the Mindlin problem. The proposed joint element has several desirable characteristics: multi-dimensionality, orientation-independence, invariance with respect to rigid-body motions and separate joint element matrices. Thus, it can be implemented into existing finite element software system and the resulting model can be solved by employing a partitioned simulation algorithm. Numerical examples are used to demonstrate these properties and the modeling abilities of proposed joint elements. The proposed joint model is implemented as part of the partitioned analysis software frame which is specifically developed for dynamic modeling of heterogeneous jointed structures. The partitioned solution algorithm utilizes a scaled localized version of the method of Lagrange multipliers that improves the conditioning of the ill-conditioned system stiffness matrices emanating from heterogeneous interface flexibilities. The partitioned system equations of motion are solved for the dynamics of each substructure coupled with the interface joint models using the mid-point integration rule and modified Newton's iteration method. Numerical experiments illustrate that the solution algorithm yields accurate and stable solutions. The thesis also presents an inverse procedure to identify the nonlinear joint model. The procedure is based on the relation between the isolated analytical joint FRFs and the global experimental ones. The partitioning of the global structures by the method of localized Lagrange multipliers and localized system identification techniques are used to identify the equivalent linear joint model. Then, the nonlinear joint parameters are indirectly determined by correlating with the equivalent linearized joint matrices and the experimental data. The application of the procedure to a bolted beam structure shows that the identified joint model traces the predominant joint FRFs and the error of the reconstructed system response is within tolerance.

  20. Naturally rare versus newly rare: demographic inferences on two timescales inform conservation of Galápagos giant tortoises.

    PubMed

    Garrick, Ryan C; Kajdacsi, Brittney; Russello, Michael A; Benavides, Edgar; Hyseni, Chaz; Gibbs, James P; Tapia, Washington; Caccone, Adalgisa

    2015-02-01

    Long-term population history can influence the genetic effects of recent bottlenecks. Therefore, for threatened or endangered species, an understanding of the past is relevant when formulating conservation strategies. Levels of variation at neutral markers have been useful for estimating local effective population sizes (N e ) and inferring whether population sizes increased or decreased over time. Furthermore, analyses of genotypic, allelic frequency, and phylogenetic information can potentially be used to separate historical from recent demographic changes. For 15 populations of Galápagos giant tortoises (Chelonoidis sp.), we used 12 microsatellite loci and DNA sequences from the mitochondrial control region and a nuclear intron, to reconstruct demographic history on shallow (past ?100 generations, ?2500 years) and deep (pre-Holocene, >10 thousand years ago) timescales. At the deep timescale, three populations showed strong signals of growth, but with different magnitudes and timing, indicating different underlying causes. Furthermore, estimated historical N e of populations across the archipelago showed no correlation with island age or size, underscoring the complexity of predicting demographic history a priori. At the shallow timescale, all populations carried some signature of a genetic bottleneck, and for 12 populations, point estimates of contemporary N e were very small (i.e., < 50). On the basis of the comparison of these genetic estimates with published census size data, N e generally represented ?0.16 of the census size. However, the variance in this ratio across populations was considerable. Overall, our data suggest that idiosyncratic and geographically localized forces shaped the demographic history of tortoise populations. Furthermore, from a conservation perspective, the separation of demographic events occurring on shallow versus deep timescales permits the identification of naturally rare versus newly rare populations; this distinction should facilitate prioritization of management action. PMID:25691990

  1. Naturally rare versus newly rare: demographic inferences on two timescales inform conservation of Galápagos giant tortoises

    PubMed Central

    Garrick, Ryan C; Kajdacsi, Brittney; Russello, Michael A; Benavides, Edgar; Hyseni, Chaz; Gibbs, James P; Tapia, Washington; Caccone, Adalgisa

    2015-01-01

    Long-term population history can influence the genetic effects of recent bottlenecks. Therefore, for threatened or endangered species, an understanding of the past is relevant when formulating conservation strategies. Levels of variation at neutral markers have been useful for estimating local effective population sizes (Ne) and inferring whether population sizes increased or decreased over time. Furthermore, analyses of genotypic, allelic frequency, and phylogenetic information can potentially be used to separate historical from recent demographic changes. For 15 populations of Galápagos giant tortoises (Chelonoidis sp.), we used 12 microsatellite loci and DNA sequences from the mitochondrial control region and a nuclear intron, to reconstruct demographic history on shallow (past ?100 generations, ?2500 years) and deep (pre-Holocene, >10 thousand years ago) timescales. At the deep timescale, three populations showed strong signals of growth, but with different magnitudes and timing, indicating different underlying causes. Furthermore, estimated historical Ne of populations across the archipelago showed no correlation with island age or size, underscoring the complexity of predicting demographic history a priori. At the shallow timescale, all populations carried some signature of a genetic bottleneck, and for 12 populations, point estimates of contemporary Ne were very small (i.e., < 50). On the basis of the comparison of these genetic estimates with published census size data, Ne generally represented ?0.16 of the census size. However, the variance in this ratio across populations was considerable. Overall, our data suggest that idiosyncratic and geographically localized forces shaped the demographic history of tortoise populations. Furthermore, from a conservation perspective, the separation of demographic events occurring on shallow versus deep timescales permits the identification of naturally rare versus newly rare populations; this distinction should facilitate prioritization of management action. PMID:25691990

  2. Computer History

    NSDL National Science Digital Library

    Mr. Cannon

    2005-12-10

    Some Websites Exploring the History of the Personal Computer Wow! What a lot of websites about computer history. Here's a few that I found...Check them out and then, when you get back here, go Take the Quiz . The List of Cool Sites Museum of Computer History The History of Computing Project The Computer Comes Home: A History of Personal Computing Computer History Museum ...

  3. Joint Instability and Osteoarthritis

    PubMed Central

    Blalock, Darryl; Miller, Andrew; Tilley, Michael; Wang, Jinxi

    2015-01-01

    Joint instability creates a clinical and economic burden in the health care system. Injuries and disorders that directly damage the joint structure or lead to joint instability are highly associated with osteoarthritis (OA). Thus, understanding the physiology of joint stability and the mechanisms of joint instability-induced OA is of clinical significance. The first section of this review discusses the structure and function of major joint tissues, including periarticular muscles, which play a significant role in joint stability. Because the knee, ankle, and shoulder joints demonstrate a high incidence of ligament injury and joint instability, the second section summarizes the mechanisms of ligament injury-associated joint instability of these joints. The final section highlights the recent advances in the understanding of the mechanical and biological mechanisms of joint instability-induced OA. These advances may lead to new opportunities for clinical intervention in the prevention and early treatment of OA. PMID:25741184

  4. Identifying image preferences based on demographic attributes

    NASA Astrophysics Data System (ADS)

    Fedorovskaya, Elena A.; Lawrence, Daniel R.

    2014-02-01

    The intent of this study is to determine what sorts of images are considered more interesting by which demographic groups. Specifically, we attempt to identify images whose interestingness ratings are influenced by the demographic attribute of the viewer's gender. To that end, we use the data from an experiment where 18 participants (9 women and 9 men) rated several hundred images based on "visual interest" or preferences in viewing images. The images were selected to represent the consumer "photo-space" - typical categories of subject matter found in consumer photo collections. They were annotated using perceptual and semantic descriptors. In analyzing the image interestingness ratings, we apply a multivariate procedure known as forced classification, a feature of dual scaling, a discrete analogue of principal components analysis (similar to correspondence analysis). This particular analysis of ratings (i.e., ordered-choice or Likert) data enables the investigator to emphasize the effect of a specific item or collection of items. We focus on the influence of the demographic item of gender on the analysis, so that the solutions are essentially confined to subspaces spanned by the emphasized item. Using this technique, we can know definitively which images' ratings have been influenced by the demographic item of choice. Subsequently, images can be evaluated and linked, on one hand, to their perceptual and semantic descriptors, and, on the other hand, to the preferences associated with viewers' demographic attributes.

  5. Demographic analysis from summaries of an age-structured population.

    PubMed

    Link, William A; Royle, J Andrew; Hatfield, Jeff S

    2003-12-01

    Demographic analyses of age-structured populations typically rely on life history data for individuals, or when individual animals are not identified, on information about the numbers of individuals in each age class through time. While it is usually difficult to determine the age class of a randomly encountered individual, it is often the case that the individual can be readily and reliably assigned to one of a set of age classes. For example, it is often possible to distinguish first-year from older birds. In such cases, the population age structure can be regarded as a latent variable governed by a process prior, and the data as summaries of this latent structure. In this article, we consider the problem of uncovering the latent structure and estimating process parameters from summaries of age class information. We present a demographic analysis for the critically endangered migratory population of whooping cranes (Grus americana), based only on counts of first-year birds and of older birds. We estimate age and year-specific survival rates. We address the controversial issue of whether management action on the breeding grounds has influenced recruitment, relating recruitment rates to the number of seventh-year and older birds, and examining the pattern of variation through time in this rate. PMID:14969455

  6. Demographic analysis from summaries of an age-structured population

    USGS Publications Warehouse

    Link, W.A.; Royle, J.A.; Hatfield, J.S.

    2003-01-01

    Demographic analyses of age-structured populations typically rely on life history data for individuals, or when individual animals are not identified, on information about the numbers of individuals in each age class through time. While it is usually difficult to determine the age class of a randomly encountered individual, it is often the case that the individual can be readily and reliably assigned to one of a set of age classes. For example, it is often possible to distinguish first-year from older birds. In such cases, the population age structure can be regarded as a latent variable governed by a process prior, and the data as summaries of this latent structure. In this article, we consider the problem of uncovering the latent structure and estimating process parameters from summaries of age class information. We present a demographic analysis for the critically endangered migratory population of whooping cranes (Grus americana), based only on counts of first-year birds and of older birds. We estimate age and year-specific survival rates. We address the controversial issue of whether management action on the breeding grounds has influenced recruitment, relating recruitment rates to the number of seventh-year and older birds, and examining the pattern of variation through time in this rate.

  7. Prevalence, demographics and clinical characteristics of multiple sclerosis in Qatar.

    PubMed

    Deleu, Dirk; Mir, Danial; Al Tabouki, Ahmed; Mesraoua, Rim; Mesraoua, Boulenouar; Akhtar, Naveed; Al Hail, Hassan; D'souza, Atlantic; Melikyan, Gayane; Imam, Yahia Z B; Osman, Yasir; Elalamy, Osama; Sokrab, Tageldin; Kamran, Sadaat; Ruiz Miyares, Francisco; Ibrahim, Faiza

    2013-05-01

    No published epidemiologic data on multiple sclerosis (MS) in Qatar exist. Our objectives were to determine the prevalence, demographics and clinical characteristics of MS in the Middle Eastern country of Qatar. We analyzed data for Qatari MS patients fulfilling the McDonald diagnostic criteria. A total of 154 patients fulfilled the inclusion criteria. On 31 April 2010, the crude prevalence of MS in Qatar was 64.57 per 100,000 inhabitants (95% CI: 58.31-70.37). The female-to-male ratio was 1.33:1. A positive family history was found in 10.4% of included MS patients. We conclude that Qatar is now a medium-to-high risk area for MS, with some important differences in clinical characteristics as compared to other countries in the region. PMID:22968545

  8. Demographic change and carbon dioxide emissions.

    PubMed

    O'Neill, Brian C; Liddle, Brant; Jiang, Leiwen; Smith, Kirk R; Pachauri, Shonali; Dalton, Michael; Fuchs, Regina

    2012-07-14

    Relations between demographic change and emissions of the major greenhouse gas carbon dioxide (CO(2)) have been studied from different perspectives, but most projections of future emissions only partly take demographic influences into account. We review two types of evidence for how CO(2) emissions from the use of fossil fuels are affected by demographic factors such as population growth or decline, ageing, urbanisation, and changes in household size. First, empirical analyses of historical trends tend to show that CO(2) emissions from energy use respond almost proportionately to changes in population size and that ageing and urbanisation have less than proportional but statistically significant effects. Second, scenario analyses show that alternative population growth paths could have substantial effects on global emissions of CO(2) several decades from now, and that ageing and urbanisation can have important effects in particular world regions. These results imply that policies that slow population growth would probably also have climate-related benefits. PMID:22784534

  9. Epidemic models for complex networks with demographics.

    PubMed

    Jin, Zhen; Sun, Guiquan; Zhu, Huaiping

    2014-12-01

    In this paper, we propose and study network epidemic models with demographics for disease transmission. We obtain the formula of the basic reproduction number R0 of infection for an SIS model with births or recruitment and death rate. We prove that if R0 ? 1 , infection-free equilibrium of SIS model is globally asymptotically stable; if R0 > 1 , there exists a unique endemic equilibrium which is globally asymptotically stable. It is also found that demographics has great effect on basic reproduction number R0. Furthermore, the degree distribution of population varies with time before it reaches the stationary state. PMID:25365609

  10. Proprioception and joint stability

    Microsoft Academic Search

    J. Jerosch; M. Prymka

    1996-01-01

    In the present paper the current clinical knowledge about proprioception is given for the shoulder, knee, ankle, elbow and the radiocarpal joint. Proprioceptive capabilities are decreased after joint injuries such as ACL or meniscus tears, shoulder dislocation, ankle sprain and in joints with degenerative joint disease. Some surgical procedures seem to restore the proprioceptive abilities; others do not. Elastic knee

  11. Joint Infection (Beyond the Basics)

    MedlinePLUS

    ... Infection of an artificial joint is known as prosthetic joint infection. GONOCOCCAL JOINT INFECTION Gonococcal joint infection ... cases, it is not possible to replace the prosthetic joint, and surgery to fuse the bones is ...

  12. American Cultural History History 390

    E-print Network

    Abolmaesumi, Purang

    . popular), theses, the Web Check subject guide under: Research by Subject History by Region American1 American Cultural History History 390 Consider Resources Primary Resources: diaries, letters collection unless stated. Album of American History E178 .A2 A (5 volumes; Stauffer ­ Books) Columbia

  13. Demographic variation in the U.K. serotine bat: filling gaps in knowledge for management

    PubMed Central

    Chauvenet, Alienor L M; Hutson, Anthony M; Smith, Graham C; Aegerter, James N

    2014-01-01

    Species of conservation concern, or those in conflict with man, are most efficiently managed with an understanding of their population dynamics. European bats exemplify the need for successful and cost-effective management for both reasons, often simultaneously. Across Europe, bats are protected, and the concept of Favourable Conservation Status (FCS) is used as a key tool for the assessment and licensing of disruptive actions to populations. However, for efficient decision-making, this assessment requires knowledge on the demographic rates and long-term dynamics of populations. We used capture–mark–recapture to describe demographic rates for the Serotine bat (Eptesicus serotinus) at two sites in England and investigate the transition rates between three stages: juveniles, immatures, and breeders. We then use these rates in an individual-based population dynamics model to investigate the expected trajectories for both populations. Our results demonstrate for the first time the presence and scale of temporal variation in this species' demography. We describe the lengthy prereproductive period (3.5 years) that female Serotines experience. Finally, we show how site-specific variation in demographic rates can produce divergent population trajectories. Effective management of European bat populations can be achieved through the understanding of life histories, and local demographic rates and population dynamics, in order to anticipate the presence of source and sink sites in the landscape. Using the Serotine bat in England, we show that these can be obtained from rigorous and systematic studies of long-term demographic datasets. PMID:25614796

  14. One-year outcomes after minimally invasive sacroiliac joint fusion with a series of triangular implants: a multicenter, patient-level analysis

    PubMed Central

    Sachs, Donald; Capobianco, Robyn; Cher, Daniel; Holt, Timothy; Gundanna, Mukund; Graven, Timothy; Shamie, A Nick; Cummings, John

    2014-01-01

    Background Sacroiliac joint (SI) pain is an often-overlooked cause of lower-back pain, due in part to a lack of specific findings on radiographs and a symptom profile similar to other back-related disorders. A minimally invasive surgical (MIS) approach to SI joint fusion using a series of triangular, titanium plasma spray-coated implants has shown favorable outcomes in patients with SI joint pain refractory to conservative care. The aim of this study was to provide a multicenter experience of MIS SI joint fusion using a patient-level analysis. Patients and methods We report a patient-level analysis from 144 patients with a mean of 16 months postoperative follow-up. Demographic information, perioperative measures, complications, and clinical outcomes using a visual analog scale for pain were collected prospectively. Random-effects regression models were used to account for intersite variability. Results The mean age was 58 years, 71% of patients were female, and 62% had a history of lumbar spinal fusion. Mean (95% confidence interval [CI]) operative time was 73 minutes (25.4–118), blood loss was minimal, and hospital stay was 0.8 days (0.1–1.5). At follow-up, mean (95% CI) visual analog scale pain scores improved by 6.1 points (5.7–6.6). Substantial clinical benefit, defined as a decrease in pain by >2.5 points or a score of 3.5 or less, was achieved in 91.9% of patients (95% CI 83.9%–96.1%), and 96% (95% CI 86.3%–98.8%) of patients indicated they would have the same surgery again. Conclusion When conservative measures fail to relieve symptoms resulting from degeneration or disruption of the SI joint, MIS SI joint fusion using a series of triangular, porous, titanium plasma spray-coated implants is a safe and effective treatment option. PMID:25210479

  15. Ghana. Country Demographic Profiles, No. 5.

    ERIC Educational Resources Information Center

    Bureau of the Census (DOC), Suitland, MD. Population Div.

    Tables of demographic information about Ghana are presented, including size of population and estimates of fertility and mortality. The data were obtained primarily from population censuses in 1960 and 1970, a 1960 post-enumeration survey, and a 1971 supplementary enquiry. Because Ghana's vital registration system is incomplete, the data are not…

  16. Prescription Drug Expenditures and Population Demographics

    PubMed Central

    Morgan, Steven G

    2006-01-01

    Objective To provide detailed demographic profiles of prescription drug utilization and expenditures in order to isolate the impact of demographic change from other factors that affect drug expenditure trends. Data Sources/Study Setting Demographic information and drug utilization data were extracted for virtually the entire British Columbia (BC) population of 1996 and 2002. All residents had public medical and hospital insurance; however their drug coverage resembled the mix of private and public insurance in the United States. Study Design A series of research variables were constructed to illustrate profiles of drug expenditures and drug utilization across 96 age/sex strata. Data Collection/Extraction Methods Drug use and expenditure information was extracted from the BC PharmaNet, a computer network connecting all pharmacies in the province. Principal Findings Per capita drug expenditures increased at an average annual rate of 10.8 percent between 1996 and 2002. Population aging explained 1.0 points of this annual rate of expenditure growth; the balance was attributable to rising age/sex-specific drug expenditures. Conclusions Relatively little of the observed increase in drug expenditures in BC could be attributed to demographic change. Most of the expenditure increase stemmed from the age/sex-specific quantity and type of drugs purchased. The sustainability of drug spending therefore depends not on outside forces but on decisions made by policy makers, prescribers, and patients. PMID:16584456

  17. Understanding China's Demographic Dividends and Labor Issue

    ERIC Educational Resources Information Center

    Peng, Xizhe

    2013-01-01

    One of the major concerns about the one-child policy is its negative impact on the current and future labor force in China. People have talked about the Lewis Turning Point and the end of demographic dividends. Some of these arguments, however, can be misleading. The working-age population (ages 15 to 59) can be treated as the potential labor…

  18. Demographic and Lifestyle Variables Associated with Obesity

    ERIC Educational Resources Information Center

    Worthy, Sheri L.; Lokken, Kristine; Pilcher, Kenneth; Boeka, Abbe

    2010-01-01

    Objective: Overweight and obesity rates are associated with chronic diseases and higher rates of disability and continue to rise in the United States and worldwide. The purpose of this study was to build on past research and further investigate demographic and lifestyle variables associated with increased body mass index (BMI: kg/m[squared]).…

  19. [The demographic situation in European countries].

    PubMed

    Smolinski, Z

    1983-06-01

    Demographic trends in European countries are summarized for the period 1960 to 1980 using data taken primarily from published sources, including those of the Council of Europe and the United Nations. Information is included on age composition, natural increase, births, infant mortality, marriages and divorces, and population projections to the year 2000. The data are presented separately for Socialist and capitalist countries. PMID:12265692

  20. COUNTING HEADS : ISRAEL 'S DEMOGRAPHIC IMPERATIVE

    Microsoft Academic Search

    Kristofer J. Petersen-Overton

    Israel is a country uniquely affected by demography , insofar as the state is bound by an explicitly Jewish nature. This balance has forced Israel to combat external demographic threats from before 1948 up until the present. The implementation of policies i ncluding the endorsement of \\

  1. Performance Review Form Overview for Supervisors Demographic

    E-print Network

    Quigg, Chris

    Performance Review Form Overview for Supervisors Demographic Data · Enter Personal Data. · Include name(s) of any matrix-level managers (optional). Performance goals and/or job responsibilities · Insert 4-6 performance goals and/or job responsibilities. · Enter results and accomplishments. · Include

  2. Economic and Demographic Predictors of Inclusive Education

    ERIC Educational Resources Information Center

    Cosier, Meghan E.; Causton-Theoharis, Julie

    2011-01-01

    This study investigated economic and demographic predictors of levels of inclusion of students with disabilities in 129 school districts. Multiple regression analysis was utilized to address the following research questions: (a) Is there a relationship between economic factors and percentage of highly included students with disabilities in general…

  3. The Demographics of Corporal Punishment in Texas

    ERIC Educational Resources Information Center

    Phillips, Stephanie

    2012-01-01

    This dissertation examined the student discipline policies of 1,025 Texas school districts, as well as data from the Texas Education Agency's Academic Excellence Indicator System in order to identify demographic patterns regarding corporal punishment policies in Texas schools. The study also studied the relationship between a district's…

  4. Demographic Group Differences in Adolescents' Time Attitudes

    ERIC Educational Resources Information Center

    Andretta, James R.; Worrell, Frank C.; Mello, Zena R.; Dixson, Dante D.; Baik, Sharon H.

    2013-01-01

    In the present study, we examined demographic differences in time attitudes in a sample of 293 adolescents. Time attitudes were measured using the Adolescent Time Attitude Scale (Mello & Worrell, 2007; Worrell, Mello, & Buhl, 2011), which assesses positive and negative attitudes toward the past, the present, and the future. Generally, African…

  5. Optimal Response to a Demographic Shock

    Microsoft Academic Search

    Juan Carlos Conesa; Carlos Garriga

    2004-01-01

    We examine the optimal policy response to an exogenously given demographic shock. Such a shock affects negatively the financing of retirement pensions, and we use optimal fiscal policy in order to determine the optimal strategy of the social security administration. Our approach provides specific policy responses in an environment that guarantees the financial sustainability of existing retirement pensions. At the

  6. Film Studies MA (Joint Honours Degrees)

    E-print Network

    Brierley, Andrew

    94 Film Studies MA (Joint Honours Degrees) Film Studies and one of: Ancient History Arabic Art universities. Times Higher Education World Rankings 2012-2013. Features * Film Studies is open to those who have had no previous experience of learning about cinema as well as those who may have studied film

  7. Star Cluster Demographics. I. A General Framework and Application to the Antennae Galaxies

    Microsoft Academic Search

    Bradley C. Whitmore; Rupali Chandar; S. Michael Fall

    2006-01-01

    We present a framework for understanding the demographics of star cluster\\u000asystems, and develop a toy model which incorporates a universal initial power\\u000alaw mass function, selected formation histories, selected disruption laws, and\\u000aa convolution with common artifacts and selection effects found in\\u000aobservational data. The model confirms that the observed correlation between\\u000athe brightest young cluster in a galaxy

  8. Adult mortality in sub-Saharan Africa: Evidence from demographic and health surveys

    Microsoft Academic Search

    Ian M. Timćus; Momodou Jasseh

    2004-01-01

    This article reports levels, trends, and age patterns of adult mortality in 23 sub-Saharan Africa countries, based on the\\u000a sibling histories and orphanhood data collected by the countries’ Demographic and Health Surveys. Adult mortality has risen\\u000a sharply since HIV became prevalent, but the size and speed of the mortality increase varies greatly among countries. Excess\\u000a mortality is concentrated among women

  9. Family History

    MedlinePLUS

    ... Home CDC 24/7: Saving Lives. Protecting People.™ Genomics All CDC Topics Search The CDC Note: Javascript ... visit this page: About CDC.gov . Public Health Genomics Genomics Family Health History Share Compartir Family History ...

  10. Local adaptation under demographic and genetic fluctuations 

    E-print Network

    Banglawala, Neelofer

    2010-01-01

    Evolution frequently plays out over ecological timescales. Local adaptation under the joint action of evolutionary and ecological processes frequently leads to novel outcomes, as is evidenced by the theoretical work on ...

  11. Individual heterogeneity in life histories and eco-evolutionary dynamics.

    PubMed

    Vindenes, Yngvild; Langangen, Řystein

    2015-05-01

    Individual heterogeneity in life history shapes eco-evolutionary processes, and unobserved heterogeneity can affect demographic outputs characterising life history and population dynamical properties. Demographic frameworks like matrix models or integral projection models represent powerful approaches to disentangle mechanisms linking individual life histories and population-level processes. Recent developments have provided important steps towards their application to study eco-evolutionary dynamics, but so far individual heterogeneity has largely been ignored. Here, we present a general demographic framework that incorporates individual heterogeneity in a flexible way, by separating static and dynamic traits (discrete or continuous). First, we apply the framework to derive the consequences of ignoring heterogeneity for a range of widely used demographic outputs. A general conclusion is that besides the long-term growth rate lambda, all parameters can be affected. Second, we discuss how the framework can help advance current demographic models of eco-evolutionary dynamics, by incorporating individual heterogeneity. For both applications numerical examples are provided, including an empirical example for pike. For instance, we demonstrate that predicted demographic responses to climate warming can be reversed by increased heritability. We discuss how applications of this demographic framework incorporating individual heterogeneity can help answer key biological questions that require a detailed understanding of eco-evolutionary dynamics. PMID:25807980

  12. Butt Joint Tool Commissioning

    SciTech Connect

    Martovetsky, N N

    2007-12-06

    ITER Central Solenoid uses butt joints for connecting the pancakes in the CS module. The principles of the butt joining of the CICC were developed by the JAPT during CSMC project. The difference between the CSMC butt joint and the CS butt joint is that the CS butt joint is an in-line joint, while the CSMC is a double joint through a hairpin jumper. The CS butt joint has to carry the hoop load. The straight length of the joint is only 320 mm, and the vacuum chamber around the joint has to have a split in the clamp shell. These requirements are challenging. Fig.1 presents a CSMC joint, and Fig.2 shows a CS butt joint. The butt joint procedure was verified and demonstrated. The tool is capable of achieving all specified parameters. The vacuum in the end was a little higher than the target, which is not critical and readily correctable. We consider, tentatively that the procedure is established. Unexpectedly, we discover significant temperature nonuniformity in the joint cross section, which is not formally a violation of the specs, but is a point of concern. All testing parameters are recorded for QA purposes. We plan to modify the butt joining tool to improve its convenience of operation and provide all features necessary for production of butt joints by qualified personnel.

  13. History uncovered

    E-print Network

    Keim, Carolyn

    sent, reminding students about the survey. The survey was also advertised on the History Faculty website, and publicity materials—including posters and bookmarks—were distributed around the History Faculty. As an incentive to complete the survey, all... …………………………………………………………………………………………………………… 10 Part A: Current Use of Resources in History & Exploration of the Factors Affecting Use 3. Faculty Perceptions…………………………………………………………………………………………………………………… 13 4. History Undergraduates’ Use of Resources………………………………………………………………………………… 16 5...

  14. Semiconstrained Distal Radioulnar Joint Prosthesis

    PubMed Central

    Savvidou, Christiana; Murphy, Erin; Mailhot, Emilie; Jacob, Shushan; Scheker, Luis R.

    2013-01-01

    Distal radioulnar joint (DRUJ) problems can occur as a result of joint instability, abutment, or incongruity. The DRUJ is a weight-bearing joint; the ulnar head is frequently excised either totally or partially, and in some cases it is fused, because of degenerative, rheumatoid, or posttraumatic arthritis. Articles about these procedures report the ability to pronate and supinate, but they rarely discuss grip strength, and even less do they address lifting capacity. We report the long term results of the first 35 patients who underwent total DRUJ arthroplasty with the Aptis DRUJ prosthesis after 5 years follow-up. Surgical indications were all causes of dysfunctional DRUJ (degenerative, posttraumatic, autoimmune, congenital). We recorded data for patient demographics, range of motion (ROM), strength, and lifting capacity of the operated and of the nonoperated extremity. Pain and functional assessments were also recorded. The Aptis DRUJ prosthesis, a bipolar self-stabilizing DRUJ endoprosthesis that restores forearm function, consists of a semiconstained and modular implant designed to replace the function of the ulnar head, the sigmoid notch of the radius, and the triangular fibrocartilage ligaments. The surgical technique is presented in detail. The majority of the patients regained adequate ROM and improved their strength and lifting capacity to the operated side. Pain and activities of daily living were improved. Twelve patients experienced complications, most commonly being extensor carpi ulnaris (ECU) tendinitis, ectopic bone formation, bone resorption with stem loosening, low-grade infection, and need for ball replacement. The Aptis total DRUJ replacement prosthesis is an alternative to salvage procedures that enables a full range of motion as well as the ability to grip and lift weights encountered in daily living activities. PMID:24436788

  15. Demographic and Clinical Characteristics of People with Intellectual Disabilities with and without Substance Abuse Disorders in a Medicaid Population

    ERIC Educational Resources Information Center

    Slayter, Elspeth Maclean

    2010-01-01

    Little is known about the demographic and clinical characteristics of people with intellectual disabilities and substance abuse problems. Drawing on health care billing claims for people with Medicaid coverage aged 12-99 years, the characteristics of people with intellectual disability and a history of substance abuse (N = 9,484) were explored and…

  16. Progressive Damage Analysis of Bonded Composite Joints

    NASA Technical Reports Server (NTRS)

    Leone, Frank A., Jr.; Girolamo, Donato; Davila, Carlos G.

    2012-01-01

    The present work is related to the development and application of progressive damage modeling techniques to bonded joint technology. The joint designs studied in this work include a conventional composite splice joint and a NASA-patented durable redundant joint. Both designs involve honeycomb sandwich structures with carbon/epoxy facesheets joined using adhesively bonded doublers.Progressive damage modeling allows for the prediction of the initiation and evolution of damage within a structure. For structures that include multiple material systems, such as the joint designs under consideration, the number of potential failure mechanisms that must be accounted for drastically increases the complexity of the analyses. Potential failure mechanisms include fiber fracture, intraply matrix cracking, delamination, core crushing, adhesive failure, and their interactions. The bonded joints were modeled using highly parametric, explicitly solved finite element models, with damage modeling implemented via custom user-written subroutines. Each ply was discretely meshed using three-dimensional solid elements. Layers of cohesive elements were included between each ply to account for the possibility of delaminations and were used to model the adhesive layers forming the joint. Good correlation with experimental results was achieved both in terms of load-displacement history and the predicted failure mechanism(s).

  17. Risk Management Institute Joint Seminar Joint Seminar -

    E-print Network

    Chaudhuri, Sanjay

    around their use of leverage. Research on optimal leverage in the money management industry, howeverRisk Management Institute Joint Seminar Joint Seminar - Risk Management Institute And Department A (S14, #03-10) Speaker Prof. Wang Hefei University of Illinois, Chicago Title Leverage Management

  18. Ehlers-Danlos Syndrome: Relationship between Joint Hypermobility, Urinary Incontinence, and Pelvic Floor Prolapse

    Microsoft Academic Search

    Lisa J. McIntosh; Deborah F. Stanitski; Veronica T. Mallett; Jane D. Frahm; David A. Richardson; Mark I. Evans

    1996-01-01

    Objective: To compare the incidence of joint hypermobility and prolapse in incontinent and continent women with Ehlers-Danlos syndrome (EDS). Methods: Forty-six patients with EDS were evaluated by history and physical examination. The degree of joint mobility of shoulder, elbow, wrist, hip, knee, and ankle was evaluated by orthopedic surgeons and physical therapists. Joint range of motion measurements were obtained using

  19. [Crisis and demographic transition in Africa].

    PubMed

    Coussy, J; Vallin, J

    1996-01-01

    The main task of CEPED, the French Center on Population and Development, is to deal with the relations between population and development. The center in this paper questions the nature of the demographic consequences of adjustment policy and reforms in developing countries. There is no doubt that such policies had important social consequences. The dearth of available statistical data, however, makes it difficult and even pointless to try and dissociate the effects of adjustment policies from the economic crises which put them in place. CEPED asked a group of experts to offer their views on to what extent the global economic crisis and the structural adjustment policies effected during the early 1980s affected demographic trends over the long term in sub-Saharan Africa. Whatever effects the economic crisis and the structural adjustment policies had upon the continent will remain to be felt for years to come. Further research is therefore warranted. PMID:12178211

  20. Complexity and demographic explanations of cumulative culture.

    PubMed

    Querbes, Adrien; Vaesen, Krist; Houkes, Wybo

    2014-01-01

    Formal models have linked prehistoric and historical instances of technological change (e.g., the Upper Paleolithic transition, cultural loss in Holocene Tasmania, scientific progress since the late nineteenth century) to demographic change. According to these models, cumulation of technological complexity is inhibited by decreasing--while favoured by increasing--population levels. Here we show that these findings are contingent on how complexity is defined: demography plays a much more limited role in sustaining cumulative culture in case formal models deploy Herbert Simon's definition of complexity rather than the particular definitions of complexity hitherto assumed. Given that currently available empirical evidence doesn't afford discriminating proper from improper definitions of complexity, our robustness analyses put into question the force of recent demographic explanations of particular episodes of cultural change. PMID:25048625

  1. Complexity and Demographic Explanations of Cumulative Culture

    PubMed Central

    Querbes, Adrien; Vaesen, Krist; Houkes, Wybo

    2014-01-01

    Formal models have linked prehistoric and historical instances of technological change (e.g., the Upper Paleolithic transition, cultural loss in Holocene Tasmania, scientific progress since the late nineteenth century) to demographic change. According to these models, cumulation of technological complexity is inhibited by decreasing— while favoured by increasing—population levels. Here we show that these findings are contingent on how complexity is defined: demography plays a much more limited role in sustaining cumulative culture in case formal models deploy Herbert Simon's definition of complexity rather than the particular definitions of complexity hitherto assumed. Given that currently available empirical evidence doesn't afford discriminating proper from improper definitions of complexity, our robustness analyses put into question the force of recent demographic explanations of particular episodes of cultural change. PMID:25048625

  2. Simulation of Demographic Change in Palestinian Territories

    NASA Astrophysics Data System (ADS)

    Sumour, M. A.; El-Astal, A. H.; Shabat, M. M.; Radwan, M. A.

    Mortality, birth rates and retirement play a major role in demographic changes. In most cases, mortality rates decreased in the past century without noticeable decrease in fertility rates, leading to a significant increase in population growth. In many poor countries like Palestinian Territories the number of births has fallen and the life expectancy increased. In this paper we concentrate on measuring, analyzing and extrapolating the age structure in Palestine a few decades ago into the future. A Fortran program has been designed and used for the simulation and analysis of our statistical data. This study of demographic change in Palestine has shown that Palestinians will have in future problems as the strongest age cohorts are the above-60-year olds. We therefore recommend the increase of both the retirement age and female employment.

  3. DEMOGRAPHIC UNCERTAINTY IN ECOLOGICAL RISK ASSESSMENTS. (R825347)

    EPA Science Inventory

    We built a Ricker's model incorporating demographic stochasticity to simulate the effects of demographic uncertainty on responses of gray-tailed vole (Microtus canicaudus) populations to pesticide applications. We constructed models with mark-recapture data collected from populat...

  4. Impact of demographics on supply chain risk management practices

    E-print Network

    Kanyagui, Kenneth (Kenneth K.)

    2010-01-01

    Do demographic factors play a role in the choice of supply chain risk management practices by supply chain professionals? Are there stronger relationships between certain demographic factors and supply chain risk management ...

  5. The Demographic Transition: Causes and Consequences

    PubMed Central

    Galor, Oded

    2013-01-01

    This paper develops the theoretical foundations and the testable implications of the various mechanisms that have been proposed as possible triggers for the demographic transition. Moreover, it examines the empirical validity of each of the theories and their significance for the understanding of the transition from stagnation to growth. The analysis suggests that the rise in the demand for human capital in the process of development was the main trigger for the decline in fertility and the transition to modern growth PMID:25089157

  6. Soft Selective Sweeps in Complex Demographic Scenarios

    PubMed Central

    Wilson, Benjamin A.; Petrov, Dmitri A.; Messer, Philipp W.

    2014-01-01

    Adaptation from de novo mutation can produce so-called soft selective sweeps, where adaptive alleles of independent mutational origin sweep through the population at the same time. Population genetic theory predicts that such soft sweeps should be likely if the product of the population size and the mutation rate toward the adaptive allele is sufficiently large, such that multiple adaptive mutations can establish before one has reached fixation; however, it remains unclear how demographic processes affect the probability of observing soft sweeps. Here we extend the theory of soft selective sweeps to realistic demographic scenarios that allow for changes in population size over time. We first show that population bottlenecks can lead to the removal of all but one adaptive lineage from an initially soft selective sweep. The parameter regime under which such “hardening” of soft selective sweeps is likely is determined by a simple heuristic condition. We further develop a generalized analytical framework, based on an extension of the coalescent process, for calculating the probability of soft sweeps under arbitrary demographic scenarios. Two important limits emerge within this analytical framework: In the limit where population-size fluctuations are fast compared to the duration of the sweep, the likelihood of soft sweeps is determined by the harmonic mean of the variance effective population size estimated over the duration of the sweep; in the opposing slow fluctuation limit, the likelihood of soft sweeps is determined by the instantaneous variance effective population size at the onset of the sweep. We show that as a consequence of this finding the probability of observing soft sweeps becomes a function of the strength of selection. Specifically, in species with sharply fluctuating population size, strong selection is more likely to produce soft sweeps than weak selection. Our results highlight the importance of accurate demographic estimates over short evolutionary timescales for understanding the population genetics of adaptation from de novo mutation. PMID:25060100

  7. Demographic Effects on Passenger Transport Demand

    Microsoft Academic Search

    Markus Mehlin; Anne Klein-Hitpaß; Rita Cyganski

    \\u000a Demographic change in Germany will lead to a remarkable change in the composition of the population, particularly in terms\\u000a of the ageing of society with the prospect of a population decrease. These factors are the main determinants for future travel\\u000a demand. This chapter describes the procedure of modelling transport for 2030 and illustrates the results with regard to the\\u000a infrastructure.

  8. Demographic response of cutlassfish (Trichiurus japonicus and T. nanhaiensis) to fluctuating palaeo-climate and regional oceanographic conditions in the China seas

    NASA Astrophysics Data System (ADS)

    He, Lijun; Zhang, Aibing; Weese, David; Li, Shengfa; Li, Jiansheng; Zhang, Jing

    2014-09-01

    Glacial cycles of the Quaternary have heavily influenced the demographic history of various species. To test the evolutionary impact of palaeo-geologic and climatic events on the demographic history of marine taxa from the coastal Western Pacific, we investigated the population structure and demographic history of two economically important fish (Trichiurus japonicus and T. nanhaiensis) that inhabit the continental shelves of the East China and northern South China Seas using the mitochondrial cytochrome b sequences and Bayesian Skyline Plot analyses. A molecular rate of 2.03% per million years, calibrated to the earliest flooding of the East China Sea shelf (70-140 kya), revealed a strong correlation between population sizes and primary production. Furthermore, comparison of the demographic history of T. japonicus populations from the East China and South China Seas provided evidence of the postglacial development of the Changjiang (Yangtze River) Delta. In the South China Sea, interspecific comparisons between T. japonicus and T. nanhaiensis indicated possible evolutionary responses to changes in palaeo-productivity that were influenced by East Asian winter monsoons. This study not only provides insight into the demographic history of cutlassfish but also reveals potential clues regarding the historic productivity and regional oceanographic conditions of the Western Pacific marginal seas.

  9. Demographic response of cutlassfish (Trichiurus japonicus and T. nanhaiensis) to fluctuating palaeo-climate and regional oceanographic conditions in the China seas

    PubMed Central

    He, Lijun; Zhang, Aibing; Weese, David; Li, Shengfa; Li, Jiansheng; Zhang, Jing

    2014-01-01

    Glacial cycles of the Quaternary have heavily influenced the demographic history of various species. To test the evolutionary impact of palaeo-geologic and climatic events on the demographic history of marine taxa from the coastal Western Pacific, we investigated the population structure and demographic history of two economically important fish (Trichiurus japonicus and T. nanhaiensis) that inhabit the continental shelves of the East China and northern South China Seas using the mitochondrial cytochrome b sequences and Bayesian Skyline Plot analyses. A molecular rate of 2.03% per million years, calibrated to the earliest flooding of the East China Sea shelf (70–140?kya), revealed a strong correlation between population sizes and primary production. Furthermore, comparison of the demographic history of T. japonicus populations from the East China and South China Seas provided evidence of the postglacial development of the Changjiang (Yangtze River) Delta. In the South China Sea, interspecific comparisons between T. japonicus and T. nanhaiensis indicated possible evolutionary responses to changes in palaeo-productivity that were influenced by East Asian winter monsoons. This study not only provides insight into the demographic history of cutlassfish but also reveals potential clues regarding the historic productivity and regional oceanographic conditions of the Western Pacific marginal seas. PMID:25223336

  10. Degenerative joint disease of the acromioclavicular joint: a review.

    PubMed

    Mall, Nathan A; Foley, Emily; Chalmers, Peter N; Cole, Brian J; Romeo, Anthony A; Bach, Bernard R

    2013-11-01

    Osteoarthritis of the acromioclavicular (AC) joint is a common condition causing anterior or superior shoulder pain, especially with overhead and cross-body activities. This most commonly occurs in middle-aged individuals because of degeneration to the fibrocartilaginous disk that cushions the articulations. Diagnosis relies on history, physical examination, imaging, and diagnostic local anesthetic injection. Diagnosis can be challenging given the lack of specificity with positive physical examination findings and the variable nature of AC joint pain. Of note, symptomatic AC osteoarthritis must be differentiated from instability and subtle instability, which may have similar symptoms. Although plain radiographs can reveal degeneration, diagnosis cannot be based on this alone because similar radiographic findings can be seen in asymptomatic individuals. Nonoperative therapy can provide symptomatic relief, whereas patients with persistent symptoms can be considered for resection arthroplasty by open or arthroscopic technique. Both techniques have proven to provide predictable pain relief; however, each has its own unique set of potential complications that may be minimized with an improved understanding of the anatomical and biomechanical characteristics of the joint along with meticulous surgical technique. PMID:23649008

  11. Climatic conditions cause complex patterns of covariation between demographic traits in a long-lived raptor.

    PubMed

    Herfindal, Ivar; van de Pol, Martijn; Nielsen, Jan T; Saether, Bernt-Erik; Mřller, Anders P

    2014-11-17

    Environmental variation can induce life-history changes that can last over a large part of the lifetime of an organism. If multiple demographic traits are affected, expected changes in climate may influence environmental covariances among traits in a complex manner. Thus, examining the consequences of environmental fluctuations requires that individual information at multiple life stages is available, which is particularly challenging in long-lived species. Here, we analyse how variation in climatic conditions occurring in the year of hatching of female goshawks Accipiter gentilis (L.) affects age-specific variation in demographic traits and lifetime reproductive success (LRS). LRS decreased with increasing temperature in April in the year of hatching, due to lower breeding frequency and shorter reproductive life span. In contrast, the probability for a female to successfully breed was higher in years with a warm April, but lower LRS of the offspring in these years generated a negative covariance among fecundity rates among generations. The mechanism by which climatic conditions generated cohort effects was likely through influencing the quality of the breeding segment of the population in a given year, as the proportion of pigeons in the diet during the breeding period was positively related to annual and LRS, and the diet of adult females that hatched in warm years contained fewer pigeons. Climatic conditions experienced during different stages of individual life histories caused complex patterns of environmental covariance among demographic traits even across generations. Such environmental covariances may either buffer or amplify impacts of climate change on population growth, emphasizing the importance of considering demographic changes during the complete life history of individuals when predicting the effect of climatic change on population dynamics of long-lived species. PMID:25403010

  12. History of the Space Radiation Effects (SPACERAD) Program for the joint USAF/NASA CRRES mission. Part 1. From the origins through the launch, 1981-1990. Interim report

    SciTech Connect

    Liebowitz, R.P.

    1992-03-16

    The history narrates the Space Radiation Effects (SPACERAD) Program from its origins in 1981 through the launch of the SPACERAD experiments on the USAF/NASA Combined Release/Radiation Effects Satellite (CRRES) on July 25, 1990 and the initial data results in October 1990. The SPACERAD Program comprised a coordinated schedule of space-and-ground testing of state-of-the-art microelectronics, together with new satellite measurements of the Earth's radiation belts. The goals for the program were to produce improved standards and procedures for ground-testing future space microelectronics and new dynamic models of the radiation belts. The history discusses programmatic, management and funding issues that arose in the course of its realization.

  13. Budgetary control and demographics in employee performance evaluation

    Microsoft Academic Search

    DW Finn; L Seaton; TP Cronan

    1989-01-01

    This study examined employee performance data and found that evidence exists which supports the linkage between worker efficiency and a set of demographic factors. One may generalize from these results that budgetary control and planning could be enhanced by including an evaluation of potential employee's projected performance levels using demographic factors in the employee selection and evaluation process. These demographic

  14. Temporomandibular joint dislocation: experiences from Zaria, Nigeria

    PubMed Central

    Fomete, Benjamin; Obiadazie, Athanasius Chukwudi; Idehen, Kelvin; Okeke, Uche

    2014-01-01

    Objectives Dislocation of the temporomandibular joint may occur for various reasons. Although different invasive methods have been advocated for its treatment, this study highlights the value of non-invasive treatment options even in chronic cases in a resource-poor environment. Materials and Methods A seven-year retrospective analysis of all patients managed for temporomandibular joint dislocation in our department was undertaken. Patient demographics, risk factors associated with temporomandibular joint dislocation and treatment modalities were retrieved from patient records. Results In all, 26 patients were managed over a seven-year period. Males accounted for 62% of the patients, and yawning was the most frequent etiological factor. Conservative treatment methods were used successfully in 86.4% of the patients managed. Two (66.7%) of the three patients who needed surgical treatment developed complications, while only one (5.3%) patient who was managed conservatively developed complications. Conclusion Temporomandibular joint dislocation appears to be associated with male sex, middle age, yawning, and low socio-economic status, although these observed relationships were not statistically significant. Non-invasive methods remain an effective treatment option in this environment in view of the low socio-economic status of the patients affected. PMID:25045637

  15. Entangled History

    E-print Network

    Jordan Cotler; Frank Wilczek

    2015-02-09

    We introduce quantum history states and their mathematical framework, thereby reinterpreting and extending the consistent histories approach to quantum theory. Through thought experiments, we demonstrate that our formalism allows us to analyze a quantum version of history in which we reconstruct the past by observations. In particular, we can pass from measurements to inferences about "what happened" in a way that is sensible and free of paradox. Our framework allows for a richer understanding of the temporal structure of quantum theory, and we construct history states that embody peculiar, non-classical correlations in time.

  16. Demographic Window, H. G. Muller et al. 1 Demographic Window to Aging in the Wild: Constructing Life

    E-print Network

    MĂĽller, Hans-Georg

    to the use of mortality data from either humans or experimental animals maintained in the laboratoryDemographic Window, H. G. M¨uller et al. 1 Demographic Window to Aging in the Wild: Constructing for wild populations. A demographic key identity is established that leads to a method whereby age

  17. Life?History Variation in Contrasting Habitats: Flowering Decisions in a Clonal Perennial Herb ( Veratrum album )

    Microsoft Academic Search

    Elze Hesse; Mark Rees

    2008-01-01

    Quantifying intraspecific demographic variation pro- vides a powerful tool for exploring the diversity and evolution of life histories. We investigate how habitat-specific demographic variation and the production of multiple offspring types affect the population dynamics and evolution of delayed reproduction in a clonal perennial herb with monocarpic ramets (white hellebore). In this species, flow- ering ramets produce both seeds and

  18. Simulating the Structural Response of a Preloaded Bolted Joint

    NASA Technical Reports Server (NTRS)

    Knight, Norman F., Jr.; Phillips, Dawn R.; Raju, Ivatury S.

    2008-01-01

    The present paper describes the structural analyses performed on a preloaded bolted-joint configuration. The joint modeled was comprised of two L-shaped structures connected together using a single bolt. Each L-shaped structure involved a vertical flat segment (or shell wall) welded to a horizontal segment (or flange). Parametric studies were performed using elasto-plastic, large-deformation nonlinear finite element analyses to determine the influence of several factors on the bolted-joint response. The factors considered included bolt preload, washer-surface-bearing size, edge boundary conditions, joint segment length, and loading history. Joint response is reported in terms of displacements, gap opening, and surface strains. Most of the factors studied were determined to have minimal effect on the bolted-joint response; however, the washer-bearing-surface size affected the response significantly.

  19. Environment, migration and the European demographic deficit

    NASA Astrophysics Data System (ADS)

    Harper, Sarah

    2012-03-01

    Many countries in the more developed world, and some in the less developed, are facing new economic and social pressures associated with the ageing of their populations. Europe, in particular, is forecast to have a demographic deficit, which may be alleviated by in-migration to the region. However, several commentators have proposed that Europe will not be able to successfully compete with other regions, in particular Asia, in the coming years for the skills it will require. This letter explores these themes, arguing that climate change will increase the attractiveness of Europe as a destination of economic choice for future skilled workers, to the detriment of more environmentally challenged regions.

  20. Demographic and practice characteristics of chiropractors.

    PubMed

    Baffi, C R; Redican, K J; Morris, L; Schroeder, K K; Olsen, L K

    1988-04-01

    The purpose of this study was to determine the demographic and practice characteristics of chiropractors. A four-part survey questionnaire was developed and mailed to a national stratified (by state) random sample of chiropractors. The analysis of data revealed that most chiropractors hold an undergraduate degree, practice in an urban area, are licensed to practice in only one state, belong to their state's chiropractic association, and are active in continuing education. Other data analyzed related to income, sources of new patients and average fees charged. PMID:3385345

  1. [The demographic situation in Romania. Where to?].

    PubMed

    Boja, I

    1990-01-01

    This is the text of an interview with Vasile Ghetau on the demographic situation of Romania at the end of the Ceausescu era. Dr. Ghetau points out the high levels of infant mortality, declines in life expectancy for both sexes, and continued low levels of fertility despite vigorous pronatalist measures such as the banning of induced abortion. He suggests that these negative trends are directly linked to the fact that the regime's population policy violated individual human rights; the deteriorating economic condition of the country; and shortages of many essentials, including food, heat, medicines, and health services generally. PMID:12343118

  2. Digital History

    NSDL National Science Digital Library

    Utilizing digital and online technologies to teach different disciplines continues to be quite popular, and the Digital History website will be a most welcome find for teachers (and students) of American history. Developed in collaboration with the University of Houston, the Chicago Historical Society, the Museum of Fine Arts in Houston and several other entities the site includes an online American history textbook, an interactive timeline, a multimedia section, and a very rich selection of primary source materials. The multimedia section is a real find, as it contains several well-thought out lectures with titles like "The History of Domestic Violence", "The Cultural Civil War of the 1960s", and "America Today and America Past". Students will also appreciate the writing guide area, as it contains several short essays on how to write in a history class and how to compose a critical book review.

  3. History Explorer

    NSDL National Science Digital Library

    There are many ways to explore the various facets of history, and some of the world's leading museums have come up with a host of online multimedia tools to bring people into this subject that is sometimes erroneously perceived to be dry and uninteresting. The inventive people at the National Museum of American History have recently developed the History Explorer which allows those surfing the Web to browse through an interactive timeline of American history. The interface is composed of items from the Museum's various online collections, exhibitions and programs, such as Plymouth Rock and a world map from 1511. Visitors can zoom in and out through the timeline and its objects and also elect to toggle on or off various themes, such as "Arts and Culture", "Peopling America", and "Politics and Reform". Overall, this is a very well-thought-out tool for learning about American history and one that will engage a wide range of persons.

  4. Ethnohistorical processes, demographic structure and linguistic determinants of the Island of Vis.

    PubMed

    Skreblin, L; Simici?, L; Sujoldzi?, A

    2002-06-01

    The present paper aims at describing the most relevant background data on geomorphological, economic, ethnohistoric, demographic and linguistic features of the island of Vis. As an introduction to future holistic anthropological research on the island, it seeks to identify both internal and external impulses of change and/or continuity of the island population structure within a wider socio-cultural and historical context. The ethnohistorical and demographic data indicate a higher degree of isolation throughout history as compared to other islands in the region and a continuous depopulation trend during the last century. The analysis of the existing linguistic data on two main settlements shows a certain amount of intradialectal micro-differentiation, which is mainly due to various social and non-linguistic reasons. PMID:12137318

  5. Demographic, Maltreatment, and Neurobiological Correlates of PTSD Symptoms in Children and Adolescents

    PubMed Central

    Hooper, Stephen R.; Woolley, Donald P.; Shenk, Chad E.

    2010-01-01

    Objective?To examine the relationships of demographic, maltreatment, neurostructural and neuropsychological measures with total posttraumatic stress disorder (PTSD) symptoms.?Methods?Participants included 216 children with maltreatment histories (N = 49), maltreatment and PTSD (N = 49), or no maltreatment (N = 118). Participants received diagnostic interviews, brain imaging, and neuropsychological evaluations.?Results?We examined a hierarchical regression model comprised of independent variables including demographics, trauma and maltreatment-related variables, and hippocampal volumes and neuropsychological measures to model PTSD symptoms. Important independent contributors to this model were SES, and General Maltreatment and Sexual Abuse Factors. Although hippocampal volumes were not significant, Visual Memory was a significant contributor to this model.?Conclusions?Similar to adult PTSD, pediatric PTSD symptoms are associated with lower Visual Memory performance. It is an important correlate of PTSD beyond established predictors of PTSD symptoms. These results support models of developmental traumatology and suggest that treatments which enhance visual memory may decrease symptoms of PTSD. PMID:20008084

  6. Rwanda: a case of demographic entrapment.

    PubMed

    Bonneux, L

    1994-12-17

    When King published 3 articles about demographic entrapment, he recommended that primary health care stop targeting child mortality, indeed that oral rehydration solutions be withheld, in order to reduce population size and evade the demographic trap of a region endangered by the growth of its own population. Using Rwanda as an example, it is possible to calculate the effect of decreasing child mortality on population growth. From 1970, when there were no programs to reduce child mortality, until 1993 the birth rate remained constant and the child mortality rate slowed so that an extra 0.5/5 children would survive to their fifth birthday. Thus, most of the population growth increase of 0.5% is probably attributable to decreased child mortality. If the high mortality rate had been maintained, the growth rate would have remained at 2.9% and the population doubling time would have been 24.2 years. The actual doubling time between 1970 and 1993 was 22.1 years, so only 2 years would have been gained by increased child mortality. The problem in Rwanda was not decreased child mortality, therefore, but the constant birth rate. Rwanda has a very Catholic population which embraces the Roman Catholic Church's anti-family planning policy. It is very hard for illiterate poor to refute the teachings of the church. The collapse of Rwanda caused by its overpopulation presents an example to the world of the devastating consequences of denying effective family planning to the poor. PMID:7996966

  7. Profile: Nanoro Health and Demographic Surveillance System.

    PubMed

    Derra, Karim; Rouamba, Eli; Kazienga, Adama; Ouedraogo, Sayouba; Tahita, Marc C; Sorgho, Hermann; Valea, Innocent; Tinto, Halidou

    2012-10-01

    The Nanoro Health and Demographic Surveillance System (HDSS), located in the rural centre of Burkina Faso, was established in 2009 by the Clinical Research Unit of Nanoro with the aim of providing a core framework for clinical trials and also to support the Burkina Faso health authorities in generating epidemiological data that can contribute to the setup and assessment of health interventions. In the baseline of initial census, 54 781 individuals were recorded of whom 56.1% are female. After the initial census, vital events such as pregnancies, births, migrations and deaths have been monitored, and data on individuals and household characteristics are updated during regular 4-monthly household visits. The available data are categorized into demographic, cultural, socio-economic and health information, and are used for monitoring and evaluation of population development issues. As a young site, our objective has been to strengthen our skills and knowledge and share new scientific experiences with INDEPTH and HDSS sites in Burkina Faso. In addition, all data produced by the Nanoro HDSS will be made publicly available through the INDEPTH data sharing system. PMID:23045201

  8. Genetic Stratigraphy of Key Demographic Events in Arabia

    PubMed Central

    Fernandes, Verónica; Triska, Petr; Pereira, Joana B.; Alshamali, Farida; Rito, Teresa; Machado, Alison; Fajkošová, Zuzana; Cavadas, Bruno; ?erný, Viktor; Soares, Pedro

    2015-01-01

    At the crossroads between Africa and Eurasia, Arabia is necessarily a melting pot, its peoples enriched by successive gene flow over the generations. Estimating the timing and impact of these multiple migrations are important steps in reconstructing the key demographic events in the human history. However, current methods based on genome-wide information identify admixture events inefficiently, tending to estimate only the more recent ages, as here in the case of admixture events across the Red Sea (?8–37 generations for African input into Arabia, and 30–90 generations for “back-to-Africa” migrations). An mtDNA-based founder analysis, corroborated by detailed analysis of the whole-mtDNA genome, affords an alternative means by which to identify, date and quantify multiple migration events at greater time depths, across the full range of modern human history, albeit for the maternal line of descent only. In Arabia, this approach enables us to infer several major pulses of dispersal between the Near East and Arabia, most likely via the Gulf corridor. Although some relict lineages survive in Arabia from the time of the out-of-Africa dispersal, 60 ka, the major episodes in the peopling of the Peninsula took place from north to south in the Late Glacial and, to a lesser extent, the immediate post-glacial/Neolithic. Exchanges across the Red Sea were mainly due to the Arab slave trade and maritime dominance (from ?2.5 ka to very recent times), but had already begun by the early Holocene, fuelled by the establishment of maritime networks since ?8 ka. The main “back-to-Africa” migrations, again undetected by genome-wide dating analyses, occurred in the Late Glacial period for introductions into eastern Africa, whilst the Neolithic was more significant for migrations towards North Africa. PMID:25738654

  9. Demographic evidence of illegal harvesting of an endangered asian turtle.

    PubMed

    Sung, Yik-Hei; Karraker, Nancy E; Hau, Billy C H

    2013-12-01

    Harvesting pressure on Asian freshwater turtles is severe, and dramatic population declines of these turtles are being driven by unsustainable collection for food markets, pet trade, and traditional Chinese medicine. Populations of big-headed turtle (Platysternon megacephalum) have declined substantially across its distribution, particularly in China, because of overcollection. To understand the effects of chronic harvesting pressure on big-headed turtle populations, we examined the effects of illegal harvesting on the demography of populations in Hong Kong, where some populations still exist. We used mark-recapture methods to compare demographic characteristics between sites with harvesting histories and one site in a fully protected area. Sites with a history of illegal turtle harvesting were characterized by the absence of large adults and skewed ratios of juveniles to adults, which may have negative implications for the long-term viability of populations. These sites also had lower densities of adults and smaller adult body sizes than the protected site. Given that populations throughout most of the species' range are heavily harvested and individuals are increasingly difficult to find in mainland China, the illegal collection of turtles from populations in Hong Kong may increase over time. Long-term monitoring of populations is essential to track effects of illegal collection, and increased patrolling is needed to help control illegal harvesting of populations, particularly in national parks. Because few, if any, other completely protected populations remain in the region, our data on an unharvested population of big-headed turtles serve as an important reference for assessing the negative consequences of harvesting on populations of stream turtles. Evidencia Demográfica de la Captura Ilegal de una Tortuga Asiática en Peligro. PMID:23869813

  10. Genetic stratigraphy of key demographic events in arabia.

    PubMed

    Fernandes, Verónica; Triska, Petr; Pereira, Joana B; Alshamali, Farida; Rito, Teresa; Machado, Alison; Fajkošová, Zuzana; Cavadas, Bruno; ?erný, Viktor; Soares, Pedro; Richards, Martin B; Pereira, Luísa

    2015-01-01

    At the crossroads between Africa and Eurasia, Arabia is necessarily a melting pot, its peoples enriched by successive gene flow over the generations. Estimating the timing and impact of these multiple migrations are important steps in reconstructing the key demographic events in the human history. However, current methods based on genome-wide information identify admixture events inefficiently, tending to estimate only the more recent ages, as here in the case of admixture events across the Red Sea (?8-37 generations for African input into Arabia, and 30-90 generations for "back-to-Africa" migrations). An mtDNA-based founder analysis, corroborated by detailed analysis of the whole-mtDNA genome, affords an alternative means by which to identify, date and quantify multiple migration events at greater time depths, across the full range of modern human history, albeit for the maternal line of descent only. In Arabia, this approach enables us to infer several major pulses of dispersal between the Near East and Arabia, most likely via the Gulf corridor. Although some relict lineages survive in Arabia from the time of the out-of-Africa dispersal, 60 ka, the major episodes in the peopling of the Peninsula took place from north to south in the Late Glacial and, to a lesser extent, the immediate post-glacial/Neolithic. Exchanges across the Red Sea were mainly due to the Arab slave trade and maritime dominance (from ?2.5 ka to very recent times), but had already begun by the early Holocene, fuelled by the establishment of maritime networks since ?8 ka. The main "back-to-Africa" migrations, again undetected by genome-wide dating analyses, occurred in the Late Glacial period for introductions into eastern Africa, whilst the Neolithic was more significant for migrations towards North Africa. PMID:25738654

  11. Art History 97 Art History

    E-print Network

    Richards-Kortum, Rebecca

    History offers a wide range of courses in European, American,Asian, and Middle Eastern/Islamic art history/European, distributed over the three periods; one course in Asian from any period;and one course in the Middle East/Islamic and applied to the major as trans- fer credits or study abroad course credits.No Advanced Placement credits

  12. Art History 95 Art History

    E-print Network

    Richards-Kortum, Rebecca

    History offers a wide range of courses in European, American,Asian, and Middle Eastern/Islamic art history/European, distributed over the three periods; one course in Asian from any period;and one course in the Middle East/Islamic and applied to the major as trans- fer credits or study abroad course credits.No Advanced Placement credits

  13. The Evolution of Transfers and Life Histories

    PubMed Central

    Cyrus, C. Y.

    2012-01-01

    Much of life history theory analyzes life histories of independent, isolated individuals, who grow, forage, reproduce, and die. However, in many species social interactions such as food sharing are a key part of the life history strategy, altering the energetic budget constraint. Transfers and sharing raise reproductive success and also alter the fitness impact of other aspects of the life history. We discuss a variety of traits and behaviors for which transfers are important, synthesizing results from a number of earlier papers. Topics include the U-shaped mortality curve, post reproductive survival, causes of early life mortality decline, why intergenerational transfers evolve and co-evolve with longevity, time preference, sexual dimorphism and sexual differences in transfers, menopause, demographic advantages of social sharing, and consequences of social sharing for life history evolution. PMID:22750486

  14. Joint hypermobility in adults referred to rheumatology clinics.

    PubMed Central

    Bridges, A J; Smith, E; Reid, J

    1992-01-01

    Joint hypermobility is a rarely recognised aetiology for focal or diffuse musculoskeletal symptoms. To assess the occurrence and importance of joint hypermobility in adult patients referred to a rheumatologist, we prospectively evaluated 130 consecutive new patients for joint hypermobility. Twenty women (15%) had joint hypermobility at three or more locations (greater than or equal to 5 points on a 9 point scale). Most patients with joint hypermobility had common musculoskeletal problems as the reason for referral. Two patients referred with a diagnosis of rheumatoid arthritis were correctly reassigned a diagnosis of hypermobility syndrome. Three patients with systemic lupus erythematosus had diffuse joint hypermobility. There was a statistically significant association between diffuse joint hypermobility and osteoarthritis. Most patients (65%) had first degree family members with a history of joint hypermobility. These results show that joint hypermobility is common, familial, found in association with common rheumatic disorders, and statistically associated with osteoarthritis. The findings support the hypothesis that joint hypermobility predisposes to musculoskeletal disorders, especially osteoarthritis. PMID:1616366

  15. History Extra

    NSDL National Science Digital Library

    The official website of the BBC History magazine is a great place to learn about British history via a litany of blogs, book reviews, fun quizzes, and more. It also maintains a trove of informative podcasts dating back to 2007 that will be a joy and a delight to anyone with a penchant for history. Recent conversations cover Britain in 1914, depictions of Jesus throughout the ages, and Gandhi's early years. Additionally, users can sign up to receive updates when new podcasts are added to the site.

  16. The value of age and medical history for predicting colorectal cancer and adenomas in people referred for colonoscopy

    PubMed Central

    2011-01-01

    Background Colonoscopy is an invasive and costly procedure with a risk of serious complications. It would therefore be useful to prioritise colonoscopies by identifying people at higher risk of either cancer or premalignant adenomas. The aim of this study is to assess a model that identifies people with colorectal cancer, advanced, large and small adenomas. Methods Patients seen by gastroenterologists and colorectal surgeons between April 2004 and December 2006 completed a validated, structured self-administered questionnaire prior to colonoscopy. Information was collected on symptoms, demographics and medical history. Multinomial logistic regression was used to simultaneously assess factors associated with findings on colonoscopy of cancer, advanced adenomas and adenomas sized 6 -9 mm, and ? 5 mm. The area under the curve of ROC curve was used to assess the incremental gain of adding demographic variables, medical history and symptoms (in that order) to a base model that included only age. Results Sociodemographic variables, medical history and symptoms (from 8,204 patients) jointly provide good discrimination between colorectal cancer and no abnormality (AUC 0.83), but discriminate less well between adenomas and no abnormality (AUC advanced adenoma 0.70; other adenomas 0.67). Age is the dominant risk factor for cancer and adenomas of all sizes. Having a colonoscopy within the last 10 years confers protection for cancers and advanced adenomas. Conclusions Our models provide guidance about which factors can assist in identifying people at higher risk of disease using easily elicited information. This would allow colonoscopy to be prioritised for those for whom it would be of most benefit. PMID:21899773

  17. Temporomandibular joint dislocation.

    PubMed

    Liddell, Aaron; Perez, Daniel E

    2015-02-01

    Dislocation of the temporomandibular joint is one of many pathophysiologic joint conditions that the oral and maxillofacial surgeon is challenged with managing. Managing a dislocated joint will inevitably be the challenge of most surgeons or physicians, whether in private or academic practice. Accordingly, this article addresses the pathophysiology associated with dislocation, in addition to treatment strategies aimed at managing acute, chronic, and recurrent dislocation. PMID:25483448

  18. Family History

    MedlinePLUS

    ... Brain Aneurysm Statistics and Facts Seeking Medical Attention Pediatric Aneurysms Brain Aneurysm Causes and Risk Factors Family History Early Detection and Screening Unruptured Brain Aneurysms Subarachnoid Hemorrhage Treatment Options Aneurysm Complications Post ...

  19. Family History

    MedlinePLUS

    Your family history includes health information about you and your close relatives. Families have many factors in common, including their genes, ... as heart disease, stroke, and cancer. Having a family member with a disease raises your risk, but ...

  20. Climate History

    NSDL National Science Digital Library

    Christopher R. Scotese

    This climate history website of the PALEOMAP project provides information on climates during past geological eras using maps and animations. Also included is a discussion of the methods used to evaluate historical climate conditions.

  1. ESTIMATING A ROTATION'S SELECTION PRESSURE FOR WEEDS, BASED ON JOINTED GOATGRASS DEMOGRAPHICS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rotations are rapidly changing in the Great Plains because of no-till systems. In place of winter wheat-fallow, producers are seeking rotations comprised of a diversity of crops. To help producers plan alternative rotations, we developed an empirical simulation model that estimated the impact of v...

  2. Demographic and childhood environmental predictors of resilience in a community sample.

    PubMed

    Campbell-Sills, Laura; Forde, David R; Stein, Murray B

    2009-08-01

    Scientific investigation of resilient responses to stress and trauma has the potential to inform models of the etiology, treatment, and prevention of stress-related psychiatric disorders (e.g. posttraumatic stress disorder). Despite building interest in and investigation of resilience, many basic questions regarding this construct remain unstudied. This study contributes to the empirical literature on resilience by providing novel information on the distribution and correlates of stress resilience in the general community. A well-validated self-report measure of resilience was completed by a large sample (N=764) of respondents to a telephone-based community survey that also included questions about demographics and history of childhood maltreatment. Multiple regression analyses showed that several demographic characteristics (sex, education level, and income level) uniquely predicted subjects' resilience to stress and that, taken together, these factors explained approximately 11% of the variance in resilience. Reported history of childhood maltreatment independently contributed to prediction of resilience and explained an additional 2% of the variance in this trait. While females, individuals with lower levels of education and income, and individuals with histories of childhood maltreatment reported diminished resilience overall, the majority of variance in the resilience measure was left unexplained leaving much room for other variables to influence a person's resilience to stress. Relationships of the present results to other research on resilient and pathological stress responses are discussed, as well as implications of these findings for future investigations of resilience. PMID:19264325

  3. Demographical and Clinical Characteristics of Behcet’s Disease in Southeastern Turkey

    PubMed Central

    Sula, Bilal; Batmaz, Ibrahim; Ucmak, Derya; Yolbas, Ilyas; Akdeniz, Sedat

    2014-01-01

    Background We aimed to determine the demographic and clinical features of patients with Behcet’s disease (BD) in Southeastern Turkey. Methods In this study, files of 132 patients with BD (76 females and 56 males) who were diagnosed with BD according to the International Study Group criteria at the Department of Dermatology of Dicle University Faculty of Medicine from 2005 to 2009 were evaluated retrospectively. Demographical and clinical characteristics of the cases were recorded. Results Mean age of the cases was 32.40 ± 9.4 years (range 15 - 59 years) and male/female ratio was 0.73. The mean age at diagnosis was 28.71 ± 9.1 years. Six cases were diagnosed as juvenile BD (4.45%). Oral aphthous lesions (100%) and genital ulcers (94%) were found to be the most common findings of the disease, followed by pathergy positivity (75%), papulopustular lesions (74.2%), erythema nodosum (43.2%), thrombophlebitis (6.8%) and extragenital ulcers (6.1%). Systemic involvement was noted as joint involvement in 79.5%, ocular involvement in 28.8%, vascular involvement in 9.8%, pulmonary involvement in 2.3%, neurologic involvement in 2.3% and genitourinary system involvement in 0.8%. There was no significant difference between mucocutaneous findings and systemic involvement ratios of male and female cases. Conclusion Demographic and clinical features of BD may vary according to geographical region, gender and ethnicity. We hope that this study will contribute to the epidemiologic data of BD which may exhibit different clinical and demographic features in different parts of the world. PMID:25247023

  4. Economic implications of Mexico’s sudden demographic transition

    Microsoft Academic Search

    Fernando Sedano

    2008-01-01

    Mexico is in the midst of an unprecedented demographic transition that is changing the size and age structure of its population.\\u000a The most salient demographic change—and clearly the precursor of most other demographic changes—is the abrupt decline in the\\u000a country’s fertility rate from 6.5 in the early 1970s to the current 2.2 mark, one of the fastest declines in the

  5. The Demographics of Women in Astronomy

    NASA Astrophysics Data System (ADS)

    Urry, M.; Marvel, K. B.; Blacker, B.

    1999-12-01

    To assess the status of women in astronomy we need data. How many women are astronomers? How does this percentage change with professional level? Do women have an advantage over men in hiring or other professional opportunities, or do men have the advantage, or is the playing field level? Using recent STScI and AAS surveys, I report the gender demographics in U.S. astronomy departments in 1999. Roughly 1/4 of astronomy graduate students are women, and this percentage decreases with rank, to 6% at the full professor level. Comparing to similar data from 1992, it appears that women fall behind men at the first transition, from graduate student to postdoc, but then keep pace with men in moving to faculty positions. (There is no sign that women advance more easily than men.) Interestingly, the percentage of women is slighly higher in the larger, better known institutions than in the profession as a whole.

  6. Demographic variation in nutrition knowledge in England

    PubMed Central

    Parmenter, K.; Waller, J.; Wardle, J.

    2000-01-01

    This paper describes a nutrition knowledge survey carried out on a cross-section of the adult population of England (n = 1040), looking at knowledge relating to current dietary recommendations, sources of nutrients, healthy food choices and diet–disease links. Serious gaps in knowledge about even the basic recommendations were discovered, and there was much confusion over the relationship between diet and disease. Significant differences in knowledge between socio-demographic groups were found, with men having poorer knowledge than women, and knowledge declining with lower educational level and socio-economic status. Possible reasons for these differences and implications for public education campaigns and socio-economic inequalities in health are discussed. PMID:10751375

  7. Campylobacter Prosthetic Joint Infection

    PubMed Central

    Vasoo, Shawn; Schwab, Jeramy J.; Cunningham, Scott A.; Robinson, Trisha J.; Cass, Joseph R.; Berbari, Elie F.; Walker, Randall C.; Osmon, Douglas R.

    2014-01-01

    A 75-year-old man was diagnosed with probable Campylobacter jejuni prosthetic knee infection after a diarrheal illness. Joint aspirate and operative cultures were negative, but PCR of prosthesis sonicate fluid was positive, as was stool culture. Nineteen additional cases of Campylobacter prosthetic joint infection reported in the literature are reviewed. PMID:24523462

  8. Behavior of jointed pipelines

    Microsoft Academic Search

    Singhal

    1984-01-01

    Experimental data on the axial, bending and torsional behavior of ductile cast iron pipes with rubber gasket joints is presented. Analytical expressions are provided which predict the resistance mechanisms and behavior of the joints. The bending mechanism is found to be quite different from the axial and torsional mechanism. By repeating the tests in a specially designed soil box, the

  9. Wedge Joints for Trusses

    NASA Technical Reports Server (NTRS)

    Wood, Kenneth E.

    1987-01-01

    Structure assembled rapidly with simple hand tools. Proposed locking wedge joints enable rapid assembly of lightweight beams, towers, scaffolds, and other truss-type structures. Lightweight structure assembled from tubular struts joined at nodes by wedge pins fitting into mating slots. Joint assembled rapidly by seating wedge pin in V-shaped slots and deforming end of strut until primary pawl engages it.

  10. Demographics of a large cohort of urban chronic hepatitis C patients

    Microsoft Academic Search

    Firdous A. Siddiqui; Murray N. Ehrinpreis; James Janisse; Ravi Dhar; Elizabeth May; Milton G. Mutchnick

    2008-01-01

    Purpose  Recent studies suggest that African Americans (AA) with chronic hepatitis C (CHC) differ from non-Hispanic whites (NHW) with\\u000a respect to the natural history and mortality resulting from the complications of chronic liver disease. The aim of this study\\u000a was to examine the demographics of a large cohort of CHC patients and identify potential differences between AA and NHW.\\u000a \\u000a \\u000a \\u000a Methods  This is

  11. Handbook on dynamics of jointed structures.

    SciTech Connect

    Ames, Nicoli M.; Lauffer, James P.; Jew, Michael D.; Segalman, Daniel Joseph; Gregory, Danny Lynn; Starr, Michael James; Resor, Brian Ray

    2009-07-01

    The problem of understanding and modeling the complicated physics underlying the action and response of the interfaces in typical structures under dynamic loading conditions has occupied researchers for many decades. This handbook presents an integrated approach to the goal of dynamic modeling of typical jointed structures, beginning with a mathematical assessment of experimental or simulation data, development of constitutive models to account for load histories to deformation, establishment of kinematic models coupling to the continuum models, and application of finite element analysis leading to dynamic structural simulation. In addition, formulations are discussed to mitigate the very short simulation time steps that appear to be required in numerical simulation for problems such as this. This handbook satisfies the commitment to DOE that Sandia will develop the technical content and write a Joints Handbook. The content will include: (1) Methods for characterizing the nonlinear stiffness and energy dissipation for typical joints used in mechanical systems and components. (2) The methodology will include practical guidance on experiments, and reduced order models that can be used to characterize joint behavior. (3) Examples for typical bolted and screw joints will be provided.

  12. Strategies for joint appointments.

    PubMed

    Royle, J; Crooks, D L

    1985-01-01

    The structure and policies governing joint appointments discussed above, are developed primarily through cooperation and collaboration between nursing service and education institutions. The joint appointee participates in the process of negotiation of salary, benefits and role responsibilities and exploration of the implications of the appointment for personal career development. Implementation and maintenance of the appointment requires the collaborative efforts of the joint appointee with both contracting agencies. Factors influencing the functioning of joint appointees have been identified and strategies to facilitate functioning presented. The joint appointee must be independent in thought and action yet adaptable to work within the boundaries of two social systems with differing values and expectations. Nursing management, peers and students can provide the support needed to overcome the frustrations and to achieve the rewards inherent in successful implementation of an exciting and innovative role. PMID:3852805

  13. Digital History

    NSDL National Science Digital Library

    The Digital History website is a project of the University of Nebraska-Lincoln, designed to educate scholars and the public about the new and fast-growing academic discipline that is digital history. The home page features a semi-globe with links to the different sections atop the globe. The goal of the site is to provide access to presentations of scholars, interviews with scholars, relevant current events and news items, as well as a bibliography of digital history resources. In the "Tool Reviews" link, a visitor can read a thorough review of two tools, a timeline, and an exhibit tool from MIT's SIMILE project on open source tools. In the "Public Lectures" link, accessible from the homepage, the visitor can view portions of ten different presentations by digital history scholars, with subject matter ranging from Malcolm X to the Civil War to the Humanities and the Digital Age. Clicking on the presenter's name will lead the visitor to the portions of the presentation available for viewing, as well as a biography of the presenter, and a "live-blogged entry" about the presentation. The "Project Reviews" link, accessible on the homepage, contains reviews written by graduate students about digital history projects. Academics with projects they'd like to see reviewed, are given a contact e-mail at University of Nebraska-Lincoln.

  14. History Net

    NSDL National Science Digital Library

    The Weider History Group publishes a wide range of military history magazines, including "America's Civil War" and "Civil War Times". They've also been generous enough to create this website, which offers a wide range of articles from their different publications. First-time visitors to the homepage may want to start out by taking a shot at the "Daily Quiz", which offers up a range of questions on everything from steamship battles to military operations in the South Pacific. Next, visitors may wish to click on over to the "Features" area, which includes articles culled from the magazines on Marine POWs, the Battle of New Orleans, as well as noted gunfighter Ben Thompson and his brother Billy. Moving on, visitors can also take part in the online forums where they can ask questions about battle tactics, the history of ground warfare, and the USS Ironsides.

  15. Talking History

    NSDL National Science Digital Library

    Yet another project at the indefatigable History Department at the University at Albany, SUNY (last reviewed in the March 19, 1999 Scout Report), Talking History is a weekly broadcast/ Internet radio program that "focuses on all aspects of history: how we recall it, how we preserve it, how we interpret it, how we transform it into myth, and how we pass it on -- as teachers, researchers, archivists, museum curators, documentary filmmakers, and so on." Aimed at a non-professional audience, the program attempts to bridge the gap between professional historians and the general public. At the site, users can listen to recent and archived programs (back to 1997) in their entirety, in high or low fidelity. Recent programs include "The Religious Roots of American Radicalism," "The Invention of George Washington," "Betty Friedan and the Making of The Feminine Mystique," and "Dangerous Liaisons: Governor Dewey, Lucky Luciano, and Operation Underworld." An excellent site for the armchair historian and academic alike.

  16. Encyclopedia of Oklahoma History & Culture

    NSDL National Science Digital Library

    The 46th state, Oklahoma, presents its unusual history with the online version of The Encyclopedia of Oklahoma History and Culture. The Encyclopedia was prepared by over 500 "university-based scholars and independent historians and scholars," and was a joint effort by The Oklahoma Historical Society and Oklahoma State University Library Electronic Publishing Center. Visitors can click on the "Table of Contents" link near the bottom of the homepage to "Browse Entries Alphabetically", "Browse Entries Chronologically", or "Browse Entries by Subject". Browsing via chronology introduces visitors to Oklahoma starting with the "Precontact Era", through the "Westward Expansion" and on to "Twentieth Century to Present". Subject categories include "African Americans", "Farming", "Military", and "Petroleum". When searching, visitors will be taken to the Electronic Publishing Center Search Page, so they will need to choose the specific collection, Encyclopedia of Oklahoma History and Culture, from the drop down box, to confine the search to the Encyclopedia.

  17. History of San Marco

    NASA Technical Reports Server (NTRS)

    Caporale, A. J.

    1968-01-01

    A brief history is reported of the first San Marco project, a joint program of the United States and Italy. The Project was a three phase effort to investigate upper air density and associated ionosphere phenomena. The initial phase included the design and development of the spacecraft, the experiments, the launch complex, and a series of suborbital flights, from Wallops Island. The second phase, consisting of designing, fabricating, and testing a spacecraft for the first orbital mission, culminated in an orbital launch also from Wallops Island. The third phase consisted of further refining the experiments and spacecraft instrumentation and of establishing a full-bore scout complex in Kenya. The launch of San Marco B, in April 1967, from this complex into an equatorial orbit, concluded the initial San Marco effort.

  18. Conservation biology for suites of species: Demographic modeling for Pacific island kingfishers

    USGS Publications Warehouse

    Kesler, D.C.; Haig, S.M.

    2007-01-01

    Conservation practitioners frequently extrapolate data from single-species investigations when managing critically endangered populations. However, few researchers initiate work with the intent of making findings useful to conservation efforts for other species. We presented and explored the concept of conducting conservation-oriented research for suites of geographically separated populations with similar natural histories, resource needs, and extinction threats. An example was provided in the form of an investigation into the population demography of endangered Micronesian kingfishers (Todiramphus cinnamominus). We provided the first demographic parameter estimates for any of the 12 endangered Pacific Todiramphus species, and used results to develop a population projection matrix model for management throughout the insular Pacific. Further, we used the model for elasticity and simulation analyses with demographic values that randomly varied across ranges that might characterize congener populations. Results from elasticity and simulation analyses indicated that changes in breeding adult survival exerted the greatest magnitude of influence on population dynamics. However, changes in nestling survival were more consistently correlated with population dynamics as demographic rates were randomly altered. We concluded that conservation practitioners working with endangered Pacific kingfishers should primarily focus efforts on factors affecting nestling and breeder survival, and secondarily address fledgling juveniles and helpers. Further, we described how the generalized base model might be changed to focus on individual populations and discussed the potential application of multi-species models to other conservation situations. ?? 2007 Elsevier Ltd. All rights reserved.

  19. Demographic Transitions and Economic Miracles in Emerging Asia

    Microsoft Academic Search

    David E. Bloom; Jeffrey G. Williamson

    1997-01-01

    The demographic transition a change from high to low rates of mortality and fertility has been more dramatic in East Asia during this century than in any other region or historical period. By introducing demographic variables into an empirical model of economic growth, this essay shows that this transition has contributed substantially to East Asia's so-called economic miracle. The 'miracle'

  20. Demographic Faultlines: A Meta-Analysis of the Literature

    ERIC Educational Resources Information Center

    Thatcher, Sherry M. B.; Patel, Pankaj C.

    2011-01-01

    We propose and test a theoretical model focusing on antecedents and consequences of demographic faultlines. We also posit contingencies that affect overall team dynamics in the context of demographic faultlines, such as the study setting and performance measurement. Using meta-analysis structural equation modeling with a final data set consisting…

  1. A Classroom Activity to Illustrate the Demographic Transition

    ERIC Educational Resources Information Center

    Weihe, Paul

    2006-01-01

    A discussion of the Demographic Transition is included in many Environmental Biology or Environmental Science classes. The Demographic Transition occurs as a nation becomes more urban and wealthy, and was widely observed in the twentieth century. The phenomenon includes decreasing family size (fewer children) across generations. In this classroom…

  2. The Impact of Extrinsic Demographic Factors on Cantonese Speech Acquisition

    ERIC Educational Resources Information Center

    To, Carol K. S.; Cheung, Pamela S. P.; McLeod, Sharynne

    2013-01-01

    This study modeled the associations between extrinsic demographic factors and children's speech acquisition in Hong Kong Cantonese. The speech of 937 Cantonese-speaking children aged 2;4 to 6;7 in Hong Kong was assessed using a standardized speech test. Demographic information regarding household income, paternal education, maternal education,…

  3. The demographic basis of population regulation in columbian ground squirrels.

    PubMed

    Dobson, F S; Oli, M K

    2001-09-01

    Environmental factors influence the dynamics and regulation of biological populations through their influences on demographic variables, but demographic mechanisms of population regulation have received little attention. We investigated the demographic basis of regulation of Columbian ground squirrel (Spermophilus columbianus) populations under natural and experimentally food-supplemented conditions. Food supplementation caused substantial increases in population density, and population densities returned to pretreatment levels when the supplementation ended. Control (untreated) populations remained relatively stable throughout the study period (1981-1986). Because food resources regulated the size of the ground squirrel populations, we used life-table response experiment (LTRE) analyses to examine the demographic basis of changes in population growth rate and thus also demographic influences on population regulation. LTRE analyses of two food-manipulated populations revealed that changes in age at maturity and fertility rate of females generally made the largest contributions to observed changes in population growth rate. Thus, our results suggested that abundance of food resources regulated the size of our study populations through the effects of food resources on age at maturity and fertility rates. Our results also indicated that different demographic mechanisms can underlie population regulation under different environmental conditions, because lower juvenile survival substantially contributed to population decline, but in only one of the populations. Demographic analyses of experimental data, such as those presented here, offer a rigorous and unambiguous means to elucidate the demographic basis of population regulation and to help identify environmental factors that underlie dynamics and regulation of biological populations. PMID:18707321

  4. Developing a Global Mindset: Integrating Demographics, Sustainability, Technology, and Globalization

    ERIC Educational Resources Information Center

    Aggarwal, Raj

    2011-01-01

    Business schools face a number of challenges in responding to the business influences of demographics, sustainability, and technology--all three of which are also the fundamental driving forces for globalization. Demographic forces are creating global imbalances in worker populations and in government finances; the world economy faces…

  5. Evaluating demographic models for goat domestication using mtdna sequences

    E-print Network

    Evaluating demographic models for goat domestication using mtdna sequences Pascale GErbault demographic models for goat domestication using mtDNa sequences. Anthropozoologica 47.2 : 65-78. Routes. Notably, domestic goat (Capra hircus) did not have any wild progenitors (Capra aegagrus) in Europe before

  6. Demographic Surprises Foreshadow Change in Neoliberal Egypt Eric Denis, CNRS

    E-print Network

    Paris-Sud XI, Université de

    Demographic Surprises Foreshadow Change in Neoliberal Egypt Eric Denis, CNRS Eric.denis@univ-paris-diderot.fr Final Draft, Middle East Report, Spring 2008, Number 246 In the Egypt of 2008, half the population has. These demographic surprises have important implications for the stability of Egypt and the regimes economic

  7. Some Emerging Demographic Issues on Australia's Teaching Academic Workforce

    ERIC Educational Resources Information Center

    Hugo, Graeme

    2005-01-01

    Like other OECD nations, Australia is facing a crisis in the academic staff of its universities over the next two decades. This is a function of several factors, among which demographic elements are especially significant. The academic workforce of Australia is characterized by three distinct demographic features--age heaping, a concentration in…

  8. China's Demographic Challenge Requires an Integrated Coping Strategy

    ERIC Educational Resources Information Center

    Peng, Xizhe

    2013-01-01

    China has entered into a new stage of demographic dynamics whereby population-related challenges are more complicated than ever before. The current one-child policy should be modified. However, the anticipated impacts of such a policy change should not be over-exaggerated. China's demographic challenge requires an integrated coping strategy.…

  9. Demographic Estimation from Face Images: Human vs. Machine Performance

    E-print Network

    --Demographic estimation entails automatic estimation of age, gender and race of a person from his face image, which has, particularly age estimation, remains a challenging problem because persons belonging to the same demographic to dramatically different facial appearances of identical twins. 1.1 Proposed Approach Among the sizable

  10. Making History

    ERIC Educational Resources Information Center

    Shein, Esther

    2008-01-01

    Jennifer Dorman was in a fix. Teaching ninth-grade US history at Holicong Middle School in Doylestown, Pennsylvania, Dorman wanted to tap into her students' interest in creating "something of value not just for their teachers, but something they could share with other students and people." But that required something a conventional paper-based…

  11. World History.

    ERIC Educational Resources Information Center

    Heise, Simine; And Others

    A detailed outline summarizes a ninth-grade course in world history adaptable to average and honors classes. Material is divided into five parts. A list of 33 course goals precedes a list of 150 objectives, grouped under appropriate goal headings. The bulk of the document consists of a content outline which cites major and minor topics covered in…

  12. History & Policy

    NSDL National Science Digital Library

    It's an old saw that those who forget the past are doomed to repeat it, but the History & Policy group takes this maxim very seriously. The group represents a collaboration between the University of Cambridge, The Institute of Historical Research, and The London School of Hygiene and Tropical Medicine. The purpose of the group is to "demonstrate the relevance of history to contemporary policymaking" and to increase the influence of historical research over current policy. Currently, their core output happens to be their papers, which are available from their homepage. Visitors can click on the "H&P papers" area to read through the latest papers, and they can also browse around via subject heading. Some of the recent titles include "North Korea and the nuclear threat", "Why history matters-and why medieval history also matters", and "China, globalization and the west: A British debate, 1890-1914". Additionally, visitors can sign up to join their email list and learn more about their network of historians.

  13. Arguing History

    ERIC Educational Resources Information Center

    Clary, Renee; Wandersee, James

    2013-01-01

    The history of science illustrates some exciting--and sometimes controversial--moments. Unfortunately, textbooks tend to focus on results in a scientific discipline and only occasionally showcase an interesting historical vignette, telling the story behind those results. Although required studies may leave teachers little classroom time for…

  14. Compliant Joints For Robots

    NASA Technical Reports Server (NTRS)

    Kerley, James J., Jr.

    1990-01-01

    Compliant joints devised to accommodate misalignments of tools and/or workpieces with respect to robotic manipulators. Has characteristics and appearance of both universal-joint and cable-spring-type flexible shaft coupling. Compliance derived from elastic properties of short pieces of cable. Compliance of joint determined by lengths, distances between, relative orientations, thickness of strands, number of strands, material, amount of pretwist, and number of short pieces of cable. Worm-drive mechanism used to adjust lengths to vary compliance as needed during operation.

  15. Harvard University's Joint Center for Housing Studies

    NSDL National Science Digital Library

    Founded in 1959, the Joint Center for Housing Studies (JCHS) at Harvard is a collaborative unit affiliated with the Graduate School of Design and the Kennedy School of Government. The Center's central focus is to "analyze the dynamic relationships between housing markets and economic, demographic, and social trends, providing leaders in government, business, and the non-profit sector with the knowledge needed to develop effective policies and strategies." The site contains links to information about ongoing research projects, educational opportunities in the field, publications, and people affiliated with JCHS. The publication section is quite strong, as visitors can browse through a diverse set of publications (many of which are available at not cost) by thematic focus, including finance, community, development, and industry studies. One of the more compelling recent publications (most of which is available here) is the monograph titled Low-Income Homeownership: Examining the Unexamined Goal.

  16. Aster models for life history analysis

    Microsoft Academic Search

    Charles J. Geyer; Stuart Wagenius; Ruth G. Shaw

    2007-01-01

    We present a new class of statistical models, designed for life history analysis of plants and animals, that allow joint analysis of data on survival and reproduction over multiple years, allow for variables having different probability distributions, and correctly account for the dependence of variables on earlier variables. We illustrate their utility with an analysis of data taken from an

  17. Economics in History and the Social Sciences.

    ERIC Educational Resources Information Center

    Joint Council on Economic Education, New York, NY.

    Papers presented by social scientists at a 1974 Joint Council seminar designed to assist authors and publishers in improving existing materials or developing new texts in social studies are reproduced in this volume. The seven papers focus on how to integrate economics into elementary and secondary social studies and history courses. The first…

  18. Dhat syndrome in relation to demographic characteristics

    PubMed Central

    Khan, Nashi

    2005-01-01

    Background: The area of men's sexual health has been poorly understood, particularly with reference to South Asian cultures. The belief that losing semen is detrimental to health is a concept common to both Oriental and Occidental thinking. Aim: To estimate the number of patients with the dhat syndrome consulting different professionals in Lahore and to examine their demographic characteristics. Method: Seventy health professionals of various types were approached and asked to fill in a daily record form for all patients reporting at their clinics for a period of 1 month. Results: A total of 1777 patients were reported to attend the outpatient clinics of health professionals of various types over a period of 1 month. The majority of patients consulted hakims for professional help. Most of the patients were single, with a mean age of 24 years and had a monthly income of less than Rs 3000. Conclusion: These data have important implications for patients, professionals and researchers. The alarming number of people consulting various professionals to seek help for anxiety due to semen loss highlights the fact that research into and interventions for this neglected area of men's sexual health are urgently required.

  19. Characterizing the Demographics of Exoplanet Bulk Compositions

    NASA Astrophysics Data System (ADS)

    Rogers, Leslie

    2013-10-01

    The Kepler Mission has discovered thousands of sub-Saturn-sized transiting planet candidates. Using planet interior structure models, we constrain the bulk compositions of the more than 50 known sub-Saturn-sized transiting planets with measured masses. Our model considers fully differentiated planets comprised of up to four layers: an iron core, a silicate mantle, a water mantle, and a gas envelope. We calculate the planet interior structure by integrating the coupled differential equations describing an evolving self-gravitating body, employing modern equations of state for the iron, silicates, water, and gas. For any individual planet, a wide range of compositions is consistent with the measured mass and radius. We consider the planets as an ensemble, and discuss how thermal evolution, mass loss, and observational biases sculpt the observed planet mass-radius-insolation distribution. Understanding these effects is crucial for constraining the demographics of small planet bulk compositions and for extracting signatures of the planet formation process from the accumulating census of transiting planets with dynamical confirmation.

  20. Evaluating the Y chromosomal timescale in human demographic and lineage dating

    PubMed Central

    2014-01-01

    Y chromosome is a superb tool for inferring human evolution and recent demographic history from a paternal perspective. However, Y chromosomal substitution rates obtained using different modes of calibration vary considerably, and have produced disparate reconstructions of human history. Here, we discuss how substitution rate and date estimates are affected by the choice of different calibration points. We argue that most Y chromosomal substitution rates calculated to date have shortcomings, including a reliance on the ambiguous human-chimpanzee divergence time, insufficient sampling of deep-rooting pedigrees, and using inappropriate founding migrations, although the rates obtained from a single pedigree or calibrated with the peopling of the Americas seem plausible. We highlight the need for using more deep-rooting pedigrees and ancient genomes with reliable dates to improve the rate estimation. PMID:25215184

  1. Joint Consideration of Distal and Proximal Predictors of Premature Mortality among Serious Juvenile Offenders

    PubMed Central

    Chassin, Laurie; Piquero, Alex R.; Losoya, Sandra H.; Mansion, Andre D.; Schubert, Carol A.

    2012-01-01

    Purpose Juvenile offenders are at heightened risk of death in adolescence and young adulthood compared to adolescents in the general population. The current study extends previous research by testing the joint contributions of distal (historical and demographic characteristics) and proximal (closer to the time of the death) predictors of mortality. We also tested and whether proximal variables were potential mediators of the effects of distal variables on mortality. Methods Participants were 1,354 serious juvenile offenders, 45 (3.32%) of whom were deceased by the completion of the study. Data were collected through self-reports and official records. Results Significant distal predictors of mortality were being African-American and having a history of substance use disorder. Proximal predictors that added significantly to prediction included gun carrying, gang membership, and substance use problems. Potential mediators of the effects of substance use disorder history were continuing substance use problems and gang membership. However, proximal variables could not explain the heightened risk for African-Americans. Conclusions Gang membership, gun carrying, and substance use problems are risk factors for early mortality among juvenile offenders, but they do not explain the elevated risk for death among African Americans. Thus, further research is needed to understand the mechanisms underlying risk for premature death among African-American adolescent offenders. Implications and contributions Findings suggest that interventions to reduce substance use problems, gang membership, and gun carrying have the potential to reduce risk of mortality for serious juvenile offenders. However, these factors cannot explain the heightened risk for death among African-American participants. PMID:23415755

  2. Detecting Concerted Demographic Response across Community Assemblages Using Hierarchical Approximate Bayesian Computation

    PubMed Central

    Chan, Yvonne L.; Schanzenbach, David; Hickerson, Michael J.

    2014-01-01

    Methods that integrate population-level sampling from multiple taxa into a single community-level analysis are an essential addition to the comparative phylogeographic toolkit. Detecting how species within communities have demographically tracked each other in space and time is important for understanding the effects of future climate and landscape changes and the resulting acceleration of extinctions, biological invasions, and potential surges in adaptive evolution. Here, we present a statistical framework for such an analysis based on hierarchical approximate Bayesian computation (hABC) with the goal of detecting concerted demographic histories across an ecological assemblage. Our method combines population genetic data sets from multiple taxa into a single analysis to estimate: 1) the proportion of a community sample that demographically expanded in a temporally clustered pulse and 2) when the pulse occurred. To validate the accuracy and utility of this new approach, we use simulation cross-validation experiments and subsequently analyze an empirical data set of 32 avian populations from Australia that are hypothesized to have expanded from smaller refugia populations in the late Pleistocene. The method can accommodate data set heterogeneity such as variability in effective population size, mutation rates, and sample sizes across species and exploits the statistical strength from the simultaneous analysis of multiple species. This hABC framework used in a multitaxa demographic context can increase our understanding of the impact of historical climate change by determining what proportion of the community responded in concert or independently and can be used with a wide variety of comparative phylogeographic data sets as biota-wide DNA barcoding data sets accumulate. PMID:24925925

  3. Detecting concerted demographic response across community assemblages using hierarchical approximate Bayesian computation.

    PubMed

    Chan, Yvonne L; Schanzenbach, David; Hickerson, Michael J

    2014-09-01

    Methods that integrate population-level sampling from multiple taxa into a single community-level analysis are an essential addition to the comparative phylogeographic toolkit. Detecting how species within communities have demographically tracked each other in space and time is important for understanding the effects of future climate and landscape changes and the resulting acceleration of extinctions, biological invasions, and potential surges in adaptive evolution. Here, we present a statistical framework for such an analysis based on hierarchical approximate Bayesian computation (hABC) with the goal of detecting concerted demographic histories across an ecological assemblage. Our method combines population genetic data sets from multiple taxa into a single analysis to estimate: 1) the proportion of a community sample that demographically expanded in a temporally clustered pulse and 2) when the pulse occurred. To validate the accuracy and utility of this new approach, we use simulation cross-validation experiments and subsequently analyze an empirical data set of 32 avian populations from Australia that are hypothesized to have expanded from smaller refugia populations in the late Pleistocene. The method can accommodate data set heterogeneity such as variability in effective population size, mutation rates, and sample sizes across species and exploits the statistical strength from the simultaneous analysis of multiple species. This hABC framework used in a multitaxa demographic context can increase our understanding of the impact of historical climate change by determining what proportion of the community responded in concert or independently and can be used with a wide variety of comparative phylogeographic data sets as biota-wide DNA barcoding data sets accumulate. PMID:24925925

  4. Combining genetic and demographic data for prioritizing conservation actions: insights from a threatened fish species

    PubMed Central

    Paz-Vinas, Ivan; Comte, Lise; Chevalier, Mathieu; Dubut, Vincent; Veyssiere, Charlotte; Grenouillet, Gaël; Loot, Geraldine; Blanchet, Simon

    2013-01-01

    Abstract Prioritizing and making efficient conservation plans for threatened populations requires information at both evolutionary and ecological timescales. Nevertheless, few studies integrate multidisciplinary approaches, mainly because of the difficulty for conservationists to assess simultaneously the evolutionary and ecological status of populations. Here, we sought to demonstrate how combining genetic and demographic analyses allows prioritizing and initiating conservation plans. To do so, we combined snapshot microsatellite data and a 30-year-long demographic survey on a threatened freshwater fish species (Parachondrostoma toxostoma) at the river basin scale. Our results revealed low levels of genetic diversity and weak effective population sizes (<63 individuals) in all populations. We further detected severe bottlenecks dating back to the last centuries (200–800 years ago), which may explain the differentiation of certain populations. The demographic survey revealed a general decrease in the spatial distribution and abundance of P. toxostoma over the last three decades. We conclude that demo-genetic approaches are essential for (1) identifying populations for which both evolutionary and ecological extinction risks are high; and (2) proposing conservation plans targeted toward these at risk populations, and accounting for the evolutionary history of populations. We suggest that demo-genetic approaches should be the norm in conservation practices. We combined genetic and demographic data from a threatened freshwater fish species (Parachondrostoma toxostoma) at the river basin scale for conservation purposes. Genetic diversity and effective population sizes are very low, probably due to the strong genetic bottlenecks detected in this study. The species spatial distribution and abundance also decreased during the last decades. PMID:24567833

  5. Influence of harvesting pressure on demographic tactics: Implications for wildlife management

    USGS Publications Warehouse

    Servanty, S.; Gaillard, J.-M.; Ronchi, F.; Focardi, S.; Baubet, E.; Gimenez, O.

    2011-01-01

    Demographic tactics within animal populations are shaped by selective pressures. Exploitation exerts additional pressures so that differing demographic tactics might be expected among populations with differences in levels of exploitation. Yet little has been done so far to assess the possible consequences of exploitation on the demographic tactics of mammals, even though such information could influence the choice of effective management strategies. Compared with similar-sized ungulate species, wild boar Sus scrofa has high reproductive capabilities, which complicates population management. Using a perturbation analysis, we investigated how population growth rates (??) and critical life-history stages differed between two wild boar populations monitored for several years, one of which was heavily harvested and the other lightly harvested. Asymptotic ?? was 1??242 in the lightly hunted population and 1??115 in the heavily hunted population, while the ratio between the elasticity of adult survival and juvenile survival was 2??63 and 1??27, respectively. A comparative analysis including 21 other ungulate species showed that the elasticity ratio in the heavily hunted population was the lowest ever observed. Compared with expected generation times of similar-sized ungulates (more than 6years), wild boar has a fast life-history speed, especially when facing high hunting pressure. This is well illustrated by our results, where generation times were 3??6years in the lightly hunted population and only 2??3years in the heavily hunted population. High human-induced mortality combined with non-limiting food resources accounted for the accelerated life history of the hunted population because of earlier reproduction. Synthesis and applications. For wild boar, we show that when a population is facing a high hunting pressure, increasing the mortality in only one age-class (e.g. adults or juveniles) may not allow managers to limit population growth. We suggest that simulations of management strategies based on context-specific demographic models are useful for selecting interventions for population control. This type of approach allows the assessment of population response to exploitation by considering a range of plausible scenarios, improving the chance of selecting appropriate management actions. ?? 2011 The Authors. Journal of Applied Ecology ?? 2011 British Ecological Society.

  6. Culture - joint fluid

    MedlinePLUS

    Joint fluid culture ... fungi, or viruses grow. This is called a culture. If such microorganisms are detected, other tests may ... is no special preparation needed for the lab culture. For information on preparing for the removal of ...

  7. Healthy Joints Matter

    MedlinePLUS

    ... caused by a buildup of uric acid (YOOR-ic acid) crystals in the joints, most commonly in ... form of arthritis called psoriatic (sore-ee-AT-ic) arthritis. Rheumatoid arthritis (ROO-muh-toid ar-THRY- ...

  8. Optimization of bonded joints

    NASA Technical Reports Server (NTRS)

    Ojalvo, I. U.

    1983-01-01

    A procedure for minimizing the elastic shear stress concentration in adhesive lap joints is presented. The proposed method is based upon tapering the adherends to achieve smooth stiffness transitions and uniform shear stresses. Both single and double lap splices are considered, but numerical examples are restricted to the case of double lap joints. Nonisotropic materials and nonoptimum design limitations, such as minimum and maximum thickness adherends, load-line eccentricity, and peel stresses are treated, and typical results are presented.

  9. Joint hypermobility syndrome pain

    Microsoft Academic Search

    Rodney Grahame

    2009-01-01

    Joint hypermobility syndrome (JHS) was initially defined as the occurrence of musculoskeletal symptoms in the presence of\\u000a joint laxity and hypermobility in otherwise healthy individuals. It is now perceived as a commonly overlooked, underdiagnosed,\\u000a multifaceted, and multisystemic heritable disorder of connective tissue (HDCT), which shares many of the phenotypic features\\u000a of other HDCTs such as Marfan syndrome and Ehlers-Danlos syndrome.

  10. High pressure ceramic joint

    DOEpatents

    Ward, M.E.; Harkins, B.D.

    1993-11-30

    Many recuperators have components which react to corrosive gases and are used in applications where the donor fluid includes highly corrosive gases. These recuperators have suffered reduced life, increased service or maintenance, and resulted in increased cost. The present joint when used with recuperators increases the use of ceramic components which do not react to highly corrosive gases. Thus, the present joint used with the present recuperator increases the life, reduces the service and maintenance, and reduces the increased cost associated with corrosive action of components used to manufacture recuperators. The present joint is comprised of a first ceramic member, a second ceramic member, a mechanical locking device having a groove defined in one of the first ceramic member and the second ceramic member. The joint and the mechanical locking device is further comprised of a refractory material disposed in the groove and contacting the first ceramic member and the second ceramic member. The present joint mechanically provides a high strength load bearing joint having good thermal cycling characteristics, good resistance to a corrosive environment and good steady state strength at elevated temperatures. 4 figures.

  11. Postglacial range shift and demographic expansion of the marine intertidal snail Batillaria attramentaria.

    PubMed

    Ho, Phuong-Thao; Kwan, Ye-Seul; Kim, Boa; Won, Yong-Jin

    2015-01-01

    To address the impacts of past climate changes, particularly since the last glacial period, on the history of the distribution and demography of marine species, we investigated the evolutionary and demographic responses of the intertidal batillariid gastropod, Batillaria attramentaria, to these changes, using the snail as a model species in the northwest Pacific. We applied phylogeographic and divergence population genetic approaches to mitochondrial COI sequences from B. attramentaria. To cover much of its distributional range, 197 individuals collected throughout Korea and 507 publically available sequences (mostly from Japan) were used. Finally, a Bayesian skyline plot (BSP) method was applied to reconstruct the demographic history of this species. We found four differentiated geographic groups around Korea, confirming the presence of two distinct, geographically subdivided haplogroups on the Japanese coastlines along the bifurcated routes of the warm Tsushima and Kuroshio Currents. These two haplogroups were estimated to have begun to split approximately 400,000 years ago. Population divergence analysis supported the hypothesis that the Yellow Sea was populated by a northward range expansion of a small fraction of founders that split from a southern ancestral population since the last glacial maximum (LGM: 26,000-19,000 years ago), when the southern area became re-submerged. BSP analyses on six geographically and genetically defined groups in Korea and Japan consistently demonstrated that each group has exponentially increased approximately since the LGM. This study resolved the phylogeography of B. attramentaria as a series of events connected over space and time; while paleoceanographic conditions determining the connectivity of neighboring seas in East Asia are responsible for the vicariance of this species, the postglacial sea-level rise and warming temperatures have played a crucial role in rapid range shifts and broad demographic expansions of its populations. PMID:25691968

  12. Postglacial range shift and demographic expansion of the marine intertidal snail Batillaria attramentaria

    PubMed Central

    Ho, Phuong-Thao; Kwan, Ye-Seul; Kim, Boa; Won, Yong-Jin

    2015-01-01

    To address the impacts of past climate changes, particularly since the last glacial period, on the history of the distribution and demography of marine species, we investigated the evolutionary and demographic responses of the intertidal batillariid gastropod, Batillaria attramentaria, to these changes, using the snail as a model species in the northwest Pacific. We applied phylogeographic and divergence population genetic approaches to mitochondrial COI sequences from B. attramentaria. To cover much of its distributional range, 197 individuals collected throughout Korea and 507 publically available sequences (mostly from Japan) were used. Finally, a Bayesian skyline plot (BSP) method was applied to reconstruct the demographic history of this species. We found four differentiated geographic groups around Korea, confirming the presence of two distinct, geographically subdivided haplogroups on the Japanese coastlines along the bifurcated routes of the warm Tsushima and Kuroshio Currents. These two haplogroups were estimated to have begun to split approximately 400,000 years ago. Population divergence analysis supported the hypothesis that the Yellow Sea was populated by a northward range expansion of a small fraction of founders that split from a southern ancestral population since the last glacial maximum (LGM: 26,000–19,000 years ago), when the southern area became re-submerged. BSP analyses on six geographically and genetically defined groups in Korea and Japan consistently demonstrated that each group has exponentially increased approximately since the LGM. This study resolved the phylogeography of B. attramentaria as a series of events connected over space and time; while paleoceanographic conditions determining the connectivity of neighboring seas in East Asia are responsible for the vicariance of this species, the postglacial sea-level rise and warming temperatures have played a crucial role in rapid range shifts and broad demographic expansions of its populations. PMID:25691968

  13. Human genetic data reveal contrasting demographic patterns between sedentary and nomadic populations that predate the emergence of farming.

    PubMed

    Aimé, Carla; Laval, Guillaume; Patin, Etienne; Verdu, Paul; Ségurel, Laure; Chaix, Raphaëlle; Hegay, Tatyana; Quintana-Murci, Lluis; Heyer, Evelyne; Austerlitz, Frédéric

    2013-12-01

    Demographic changes are known to leave footprints on genetic polymorphism. Together with the increased availability of large polymorphism data sets, coalescent-based methods allow inferring the past demography of populations from their present-day patterns of genetic diversity. Here, we analyzed both nuclear (20 noncoding regions) and mitochondrial (HVS-I) resequencing data to infer the demographic history of 66 African and Eurasian human populations presenting contrasting lifestyles (nomadic hunter-gatherers, nomadic herders, and sedentary farmers). This allowed us to investigate the relationship between lifestyle and demography and to address the long-standing debate about the chronology of demographic expansions and the Neolithic transition. In Africa, we inferred expansion events for farmers, but constant population sizes or contraction events for hunter-gatherers. In Eurasia, we inferred higher expansion rates for farmers than herders with HVS-I data, except in Central Asia and Korea. Although isolation and admixture processes could have impacted our demographic inferences, these processes alone seem unlikely to explain the contrasted demographic histories inferred in populations with different lifestyles. The small expansion rates or constant population sizes inferred for herders and hunter-gatherers may thus result from constraints linked to nomadism. However, autosomal data revealed contraction events for two sedentary populations in Eurasia, which may be caused by founder effects. Finally, the inferred expansions likely predated the emergence of agriculture and herding. This suggests that human populations could have started to expand in Paleolithic times, and that strong Paleolithic expansions in some populations may have ultimately favored their shift toward agriculture during the Neolithic. PMID:24063884

  14. Organ History

    NSDL National Science Digital Library

    Cook, James H.

    Developed and maintained by Professor James H. Cook at Birmingham - Southern College, this site is an online tutorial that offers an interesting and interactive perspective of that king of all instruments, the organ. The site is divided into three main sections: The Organ and How it Works, Organ History, and Geographical Tour. In the first section, visitors are taken through a basic description of an organ, which then continues into a discussion of the various parts of an organ, such as the keyboards, consoles, pipes, chests, cases, and chambers. The history section begins with the invention of what is commonly understood to be the first organ, the ktseibios, built by a Greek engineer working in the third century BCE. The final section takes visitors on a chronological tour of the organ and its development throughout a number of countries, including England, France, Germany, Italy, and the United States.

  15. Naval History

    NSDL National Science Digital Library

    The world of naval history is quite vast, especially considering that it is linked to the earliest days of warfare and stretches back thousands of years. Designed by Gordon Smith, this particular site details the history of various national navies during the twentieth century, with a particular focus on the World Wars and other military actions. Not surprisingly, visitors to the site will want to take a look at the areas dedicated to the World Wars, as the coverage of the role of various navies is quite good here. In these sections, visitors can learn about the various ships used during each period and also look at the campaigns and battles by year and by month. There is also a rather touching section dedicated to Gordon Smith's father, George Smith, who was lost in the sinking of the HMS Charybdis off the Brittany coast on October 23rd, 1943.

  16. Pennsylvania History

    NSDL National Science Digital Library

    If you know someone who is fascinated with the history of Pennsylvania, they will want to explore this site in great detail. Created by the Pennsylvania Historical and Museum Commission, the site brings together primary documents, photographs, and a timeline of Keystone State history. The sections here include People, Places, Events, and Things. Users with a penchant for material culture will love the Things area, as it features topical sections covering Canals, Archaeology, Railroads, and Roads. The Places area provides meditations and narrative essays on the Governor's Residence and the long-gone French Asylum on the Susquehanna River, which was actually more of a utopian outpost of sorts. Also, the People area profiles well- and lesser-known individuals who left their mark on the state, including William Penn, Ida Tarbell, and noted military man, Henry Bouquet.

  17. Smart History

    NSDL National Science Digital Library

    Under the headline "Art. History. Conversation.", Dr. Beth Harris and Dr. Steven Zucker started the Smarthistory site in 2005 as a weblog that featured free audio guides. Since that time, the site as grown into a multimedia web-book "designed as a dynamic enhancement (or even substitute) for the traditional and static art history textbook." Visitors to the site will find several hundred artworks (along with videos and podcasts) organized thematically and by time period. Additionally, visitors can also use the drop down menus on the homepage to look for certain styles, artists, and themes that include "Image and Power", "The Artist as Professional", and "Bronze Casting". The videos are a real treat, and they include offerings like "Magritte's treacherous pipe" and "Mies's corporate classicism". Finally, visitors can also learn about making a donation to their group.

  18. Cygnus History

    Microsoft Academic Search

    David J. Henderson; Raymond E. Gignac; Douglas E. Good; Mark D. Hansen; Charles V. Mitton; Eugene C. Ormond Daniel S. Nelson; Isidro Molina Steve R. Cordova; Evan A. Rose John R. Smith

    2009-01-01

    The Cygnus Dual Beam Radiographic Facility consists of two identical radiographic sources: Cygnus 1 and Cygnus 2. This Radiographic Facility is located in an underground tunnel test area at the Nevada Test Site. The sources were developed to produce high-resolution images for dynamic plutonium experiments. This work will recount and discuss salient maintenance and operational issues encountered;\\u000aduring the history

  19. River history.

    PubMed

    Vita-Finzi, Claudio

    2012-05-13

    During the last half century, advances in geomorphology-abetted by conceptual and technical developments in geophysics, geochemistry, remote sensing, geodesy, computing and ecology-have enhanced the potential value of fluvial history for reconstructing erosional and depositional sequences on the Earth and on Mars and for evaluating climatic and tectonic changes, the impact of fluvial processes on human settlement and health, and the problems faced in managing unstable fluvial systems. PMID:22474674

  20. Demographics of the European apicultural industry.

    PubMed

    Chauzat, Marie-Pierre; Cauquil, Laura; Roy, Lise; Franco, Stéphanie; Hendrikx, Pascal; Ribičre-Chabert, Magali

    2013-01-01

    Over the last few years, many European and North American countries have reported a high rate of disorders (mortality, dwindling and disappearance) affecting honeybee colonies (Apis mellifera). Although beekeeping has become an increasingly professional activity in recent years, the beekeeping industry remains poorly documented in Europe. The European Union Reference Laboratory for Honeybee Health sent a detailed questionnaire to each Member State, in addition to Kosovo and Norway, to determine the demographics and state of their beekeeping industries. Based on data supplied by the National Reference Laboratory for honeybee diseases in each European country, a European database was created to describe the beekeeping industry including the number and types of beekeepers, operation size, industry production, and health (notifiable diseases, mortalities). The total number of beekeepers in Europe was estimated at 620,000. European honey production was evaluated at around 220,000 tons in 2010. The price of honey varied from 1.5 to 40 €/kg depending on the country and on the distribution network. The estimated colony winter mortality varied from 7 to 28% depending on the country and the origin of the data (institutional survey or beekeeping associations). This survey documents the high heterogeneity of the apicultural industry within the European Union. The high proportion of non-professional beekeepers and the small mean number of colonies per beekeeper were the only common characteristics at European level. The tremendous variation in European apicultural industries has implication for any comprehensive epidemiological or economic analysis of the industry. This variability needs to be taken into account for such analysis as well as for future policy development. The industry would be served if beekeeping registration was uniformly implemented across member states. Better information on the package bee and queen production would help in understanding the ability of the industry to replace lost honey bee stocks. PMID:24236084

  1. The demographics of military children and families.

    PubMed

    Clever, Molly; Segal, David R

    2013-01-01

    Since the advent of the all-volunteer force in the 1970s, marriage, parenthood, and family life have become commonplace in the U.S. military among enlisted personnel and officers alike, and military spouses and children now outnumber service members by a ratio of 1.4 to 1. Reviewing data from the government and from academic and nonacademic research, Molly Clever and David R. Segal find several trends that distinguish today's military families. Compared with civilians, for example, service members marry younger and start families earlier. Because of the requirements of their jobs, they move much more frequently than civilians do, and they are often separated from their families for months at a time. And despite steady increases since the 1970s in the percentage of women who serve, the armed forces are still overwhelmingly male, meaning that the majority of military parents are fathers. Despite these distinguishing trends, Clever and Segal's chief finding is that military families cannot be neatly pigeonholed. Instead, they are a strikingly diverse population with diverse needs. Within the military, demographic groups differ in important ways, and the service branches differ from one another as well. Military families themselves come in many forms, including not only the categories familiar from civilian life--two-parent, single-parent, and so on--but also, unique to the military, dual-service families in which both parents are service members. Moreover, military families' needs change over time as they move through personal and military transitions. Thus the best policies and programs to help military families and children are flexible and adaptable rather than rigidly structured. PMID:25518690

  2. History Detectives

    NSDL National Science Digital Library

    Thinking about detectives in general makes most people's minds wander to thoughts of those rugged personages of television dramas or to the world of literature, with a lot of mucking about in dark alleyways or the sordid world of upper-crust intrigue and deception. PBS has elected to turn that perception on its head with its new program, History Detectives. This 10-part series is devoted to "solving historical mysteries, searching out the true facts (and falsehoods) behind local folklore, family legends and interesting objects." On this site, visitors can learn about the team of detectives (which includes an auctioneer, an architecture history professor, and a sociology professor), view clips from the program, and most importantly, about their various techniques for sleuthing. What is even better is that the site also offers overviews into various techniques (such as investigating the history of a building and examining personal papers) that allow users to get out there and do their own sleuthing in their own communities.

  3. Uncovering History for Future History Teachers

    ERIC Educational Resources Information Center

    Fischer, Fritz

    2010-01-01

    The art of history teaching is at a crossroads. Recent scholarship focuses on the need to change the teaching of history so students can better learn history, and insists that history teachers must move beyond traditional structures and methods of teaching in order to improve their students' abilities to think with history. This article presents…

  4. Department of History Teaching Major in History

    E-print Network

    Vonessen, Nikolaus

    Department of History Teaching Major in History Students interested in earning a teaching major in history must complete the requirements for a BA in history, to include the following courses: 4 credits HSTR 101 or 102 European Civilization ________ 4 credits HSTA 101 or 102 American History ________ 1

  5. WTO History Project

    NSDL National Science Digital Library

    2001-01-01

    A joint project of the University of Washington's (UW's) Harry Bridges Center for Labor Studies and the University Library, the WTO History Project focuses on the history-making protests of late 1999 in Seattle during the World Trade Organization (WTO) Ministerial meetings. A particularly groovy and educational highlight of this Website is the database of fliers, posters, notes, letters, etc. that the Manuscripts, Special Collections and University Archives Division of the UW Libraries makes Internet-accessible using CONTENTdm, a multimedia database developed at the UW. "CONTENTdm allows users to create customized searches of the collection and for high-quality digital reproductions to be viewed online, enabling some research to be conducted without visiting the collection." Visitors to the WTO History Project Website will also find a timeline of events prior to and during the 1999 protests in Seattle, including locations and sponsors, and a chart of organizations (with contact information) that were vocal in their opposition to the WTO, along with a list of registered WTO meeting attendees (MS Excel). In addition, this site features a page of interview transcripts with words from more than 80 organizers of and participants in the Seattle protests (.pdf). Organizations represented here include the Industrial Workers of the World, People for Fair Trade, the AFL-CIO, and the Sierra Club, to name just a few. This is a fantastic resource for students looking for primary texts dealing with labor and globalization issues or anyone wanting to learn more about the groups and individuals involved in the WTO protests. This site is still being developed, so check back often.

  6. Demographic, agricultural products, and food consumption data for a collective farm in Oranoe District, Ivankov District, Kiev Region, Ukraine

    SciTech Connect

    Ryabov, I N [AN SSSR, Moscow (Russian Federation). Inst. of Animal Evolutionary, Morphology and Ecology ECOPOLIS, Kiev (Ukraine); Davidenko, G M [ECOPOLIS, Kiev (Ukraine); Templeton, W L [Pacific Northwest Lab, Richland, WA (United States); ,

    1992-07-01

    This report provides some demographic, agricultural and food consumption data for the collective farms ( Kybisheva,'' composed of three villages) in the Oranoe Department, District of Ivankov, Kiev Region. This area is situated approximately 15 km south of the Chernobyl 30-km Exclusion Zone. The levels of {sup 137}Cs are approximately 5--10 curies/km{sup 2}. This data was collected by the Integrated Radioecological Expedition to Chernobyl of the Russian Academy of Sciences as part of the co-operative studies on environmental radiation dose assessment conducted under the US/USSR Joint Co-operative Committee on Civilian Nuclear Reactor Safety (JCCCNRS) established in 1989.

  7. Inferences of Recent and Ancient Human Population History Using Genetic and Non-Genetic Data

    ERIC Educational Resources Information Center

    Kitchen, Andrew

    2008-01-01

    I have adopted complementary approaches to inferring human demographic history utilizing human and non-human genetic data as well as cultural data. These complementary approaches form an interdisciplinary perspective that allows one to make inferences of human history at varying timescales, from the events that occurred tens of thousands of years…

  8. Multidrug resistant Acinetobacter baumannii reaches a new frontier: prosthetic hip joint infection.

    PubMed

    Hischebeth, G T R; Wimmer, M D; Molitor, E; Seifert, H; Gravius, S; Bekeredjian-Ding, I

    2015-02-01

    Acinetobacter baumannii is an emerging nosocomial pathogen primarily in countries with a high prevalence of multidrug resistance. Here we report the detection of a bla OXA23 carbapenemase-producing A. baumannii strain in a German patient with prosthetic hip joint infection following several hip joint surgeries but no history of foreign travel. PMID:25037735

  9. Habitat and Scale Shape the Demographic Fate of the Keystone Sea Urchin Paracentrotus lividus in Mediterranean Macrophyte Communities

    PubMed Central

    Prado, Patricia; Tomas, Fiona; Pinna, Stefania; Farina, Simone; Roca, Guillem; Ceccherelli, Giulia; Romero, Javier; Alcoverro, Teresa

    2012-01-01

    Demographic processes exert different degrees of control as individuals grow, and in species that span several habitats and spatial scales, this can influence our ability to predict their population at a particular life-history stage given the previous life stage. In particular, when keystone species are involved, this relative coupling between demographic stages can have significant implications for the functioning of ecosystems. We examined benthic and pelagic abundances of the sea urchin Paracentrotus lividus in order to: 1) understand the main life-history bottlenecks by observing the degree of coupling between demographic stages; and 2) explore the processes driving these linkages. P. lividus is the dominant invertebrate herbivore in the Mediterranean Sea, and has been repeatedly observed to overgraze shallow beds of the seagrass Posidonia oceanica and rocky macroalgal communities. We used a hierarchical sampling design at different spatial scales (100 s, 10 s and <1 km) and habitats (seagrass and rocky macroalgae) to describe the spatial patterns in the abundance of different demographic stages (larvae, settlers, recruits and adults). Our results indicate that large-scale factors (potentially currents, nutrients, temperature, etc.) determine larval availability and settlement in the pelagic stages of urchin life history. In rocky macroalgal habitats, benthic processes (like predation) acting at large or medium scales drive adult abundances. In contrast, adult numbers in seagrass meadows are most likely influenced by factors like local migration (from adjoining rocky habitats) functioning at much smaller scales. The complexity of spatial and habitat-dependent processes shaping urchin populations demands a multiplicity of approaches when addressing habitat conservation actions, yet such actions are currently mostly aimed at managing predation processes and fish numbers. We argue that a more holistic ecosystem management also needs to incorporate the landscape and habitat-quality level processes (eutrophication, fragmentation, etc.) that together regulate the populations of this keystone herbivore. PMID:22536355

  10. Health & Demographic Surveillance System profile: the Muzaffarpur-TMRC Health and Demographic Surveillance System.

    PubMed

    Malaviya, Paritosh; Picado, Albert; Hasker, Epco; Ostyn, Bart; Kansal, Sangeeta; Singh, Rudra Pratap; Shankar, Ravi; Boelaert, Marleen; Sundar, Shyam

    2014-10-01

    The Muzaffarpur-TMRC Health and Demographic Surveillance System (HDSS), established in 2007, was developed as an enlargement of the scope of a research collaboration on the project Visceral Leishmaniasis in Bihar, which had been ongoing since 2005. The HDSS is located in a visceral leishmaniasis (VL)-endemic area in the Muzaffarpur district of Bihar state in India. It is the only HDSS conducting research on VL, which is a vector-borne infectious disease transmitted by female phlebotomine sandflies and is fatal if left untreated. Currently the HDSS serves a population of over 105,000 in 66 villages. The HDSS collects data on vital events including pregnancies, births, deaths, migration and marriages, as well as other socio-economic indicators, at regular intervals. Incident VL cases are identified. The HDSS team is experienced in conducting both qualitative and quantitative studies, sample collection and rapid diagnostic tests in the field. In each village, volunteers connect the HDSS team with the community members. The Muzaffarpur-TMRC HDSS provides opportunities for studies on VL and other neglected tropical diseases (NTDs) and their interaction with demographic events such as migration. Queries related to research collaborations and data sharing can be sent to Dr Shyam Sundar at [drshyamsundar@hotmail.com]. PMID:25186307

  11. Iran in History Iran in History

    E-print Network

    Mohaghegh, Shahab

    1 Iran in History Iran in History by Bernard Lewis In attempting to attain some perspective on Iran in history, I begin, as I think one must, with the Arab-Islamic conquests in the seventh century--that series

  12. Toward a Suite of Performatives Based Upon Joint Intention Theory

    Microsoft Academic Search

    Marcus J. Huber; Sanjeev Kumar; David Mcgee

    2004-01-01

    Agent communication languages defined using joint intention theory have enjoyed a long research history. A number of performatives have been defined and refined in this literature with particular emphasis on the basic performatives of REQUEST and INFORM, which subsequently have many subtle versions. Even these less common performatives have been extended and refined multiple times. In many cases the underlying

  13. Dissimilar metals joint evaluation

    NASA Technical Reports Server (NTRS)

    Wakefield, M. E.; Apodaca, L. E.

    1974-01-01

    Dissimilar metals tubular joints between 2219-T851 aluminum alloy and 304L stainless steel were fabricated and tested to evaluate bonding processes. Joints were fabricated by four processes: (1) inertia (friction) weldings, where the metals are spun and forced together to create the weld; (2) explosive welding, where the metals are impacted together at high velocity; (3) co-extrusion, where the metals are extruded in contact at high temperature to promote diffusion; and (4) swaging, where residual stresses in the metals after a stretching operation maintain forced contact in mutual shear areas. Fifteen joints of each type were prepared and evaluated in a 6.35 cm (2.50 in.) O.D. size, with 0.32 cm (0.13 in.) wall thickness, and 7.6 cm (3.0 in) total length. The joints were tested to evaluate their ability to withstand pressure cycle, thermal cycle, galvanic corrosion and burst tests. Leakage tests and other non-destructive test techniques were used to evaluate the behavior of the joints, and the microstructure of the bond areas was analyzed.

  14. Acromioclavicular Joint Injuries

    PubMed Central

    Beim, Gloria M.

    2000-01-01

    Objective: To discuss the anatomy and biomechanics of the acromioclavicular (AC) joint, along with the clinical evaluation and treatment of an athlete with an AC joint injury. Data Sources: I searched MEDLINE from 1970 through 1999 under the key words “acromioclavicular joint,” “clavicle,” “acromioclavicular separation,” and “acromioclavicular dislocation.” Knowledge base was an additional source. Data Synthesis: AC joint injury is common in athletes and a source of significant morbidity, particularly for athletes in overhead sports. Because this injury can masquerade as other shoulder conditions, the examiner must understand the anatomy and biomechanics of the shoulder in order to perform a systematic clinical evaluation and identify the injury. Conclusions/Recommendations: Careful attention to the clinical evaluation allows the clinician to categorize the athlete's AC joint injury and institute appropriate treatment in a timely fashion, thus permitting the athlete to return to sport as quickly and safely as possible. ImagesFigure 1.Figure 2.Figure 3.Figure 4.Figure 5.Figure 6.Figure 7. PMID:16558638

  15. Distal radioulnar joint injuries

    PubMed Central

    Thomas, Binu P; Sreekanth, Raveendran

    2012-01-01

    Distal radioulnar joint is a trochoid joint relatively new in evolution. Along with proximal radioulnar joint, forearm bones and interosseous membrane, it allows pronosupination and load transmission across the wrist. Injuries around distal radioulnar joint are not uncommon, and are usually associated with distal radius fractures,fractures of the ulnar styloid and with the eponymous Galeazzi or Essex_Lopresti fractures. The injury can be purely involving the soft tissue especially the triangular fibrocartilage or the radioulnar ligaments. The patients usually present with ulnar sided wrist pain, features of instability, or restriction of rotation. Difficulty in carrying loads in the hand is a major constraint for these patients. Thorough clinical examination to localize point of tenderness and appropriate provocative tests help in diagnosis. Radiology and MRI are extremely useful, while arthroscopy is the gold standard for evaluation. The treatment protocols are continuously evolving and range from conservative, arthroscopic to open surgical methods. Isolated dislocation are uncommon. Basal fractures of the ulnar styloid tend to make the joint unstable and may require operative intervention. Chronic instability requires reconstruction of the stabilizing ligaments to avoid onset of arthritis. Prosthetic replacement in arthritis is gaining acceptance in the management of arthritis. PMID:23162140

  16. History Fun

    NSDL National Science Digital Library

    Ms. Thatcher

    2006-10-17

    Games and other fun information about history. The Battle of the Atlantic Game Defeat the U-boats and guide your convoy to safety The Battle of Hastings Game Discover the tactics and try putting them into practice Gladiator: Dressed to Kill Prepare a gladiator for battle in the arena of death Viking Quest Build a ship, loot a monastery and claim your prize Pyramid Challenge Complete the construction of the pharaoh\\'s tomb Mummy Maker Prepare the body of Ramose, officer to the king, for ...

  17. Geologic History

    NSDL National Science Digital Library

    Medina, Philip

    This unit introduces younger students to the concept of relative versus absolute time and how geologists determine the age of geologic events and features. Topics include the laws that determine relative age (superposition, cross-cutting relationships, included fragments, and others), and how to re-construct the geologic history of an area using these relationships. There is also information on geologic correlation and the use of index fossils to determine relative age. The section on absolute time discusses some ways of measurement (tree rings, radioactive dating) and introduces the concepts of natural selection and mass extinctions. A vocabulary and downloadable, printable student worksheets are provided.

  18. Volcanic Histories

    NSDL National Science Digital Library

    Robert H. Filson

    To prepare for this in-class problem, students should have read about volcanism in their introductory text. Specifically they will need to know the types of volcanoes, the characteristics of volcanic products, such as lava flows of different silica compositions, tephra, lahars, and pyroclastic flows. Students should be able to connect the types of activity of a volcano to its type, such as composite volcanoes having abundant tephra, with some lava flows, while a shield volcano may have less tephra and more low viscosity lava flows. This activity is similar to the process used by geoscientists to evaluate the history and hazards of a volcano.

  19. Assessing patterns of fish demographics and habitat in stream networks

    EPA Science Inventory

    Effective habitat restoration planning requires correctly anticipating demographic responses to altered habitats. New applications of Passive Integrated Transponder (PIT) tag technology to fish-habitat research have provided critical insights into fish movement, growth, and surv...

  20. Demographics and the social reckoning in the Arab region.

    PubMed

    Kronfol, N M

    2013-04-01

    Demographic transitions in the Arab countries, due to declining birth rates and mortality rates since the 1980s, are reflected in a low proportion of children, a relatively stable proportion of elderly and a high proportion of people of working age. This "youth bulge" of young, active, working-age individuals in the current population may open a demographic window for countries to benefit from increased savings and investment. This paper reviews the demographic situation in the Arab region and the impact of education, employment, migration, health status and participation in society on the further development of the region, including the impact of these factors on ageing and gender issues. The intent is to draw attention to the importance of these demographic changes and highlight the need for action to maximize the potential benefit to the population in this region. PMID:23882965

  1. The second demographic transition: a concise overview of its development.

    PubMed

    Lesthaeghe, Ron

    2014-12-23

    This article gives a concise overview of the theoretical development of the concept of the "second demographic transition" since it was coined in 1986, its components, and its applicability, first to European populations and subsequently also to non-European societies as well. Both the demographic and the societal contrasts between the first demographic transition (FDT) and the second demographic transition (SDT) are highlighted. Then, the major criticisms of the SDT theory are outlined, and these issues are discussed in the light of the most recent developments in Europe, the United States, the Far East, and Latin America. It turns out that three major SDT patterns have developed and that these evolutions are contingent on much older systems of kinship and family organization. PMID:25453112

  2. Demographic Trends, the WildlandUrban Interface, and Wildfire Management

    E-print Network

    Fried, Jeremy S.

    Department of Sociology, Sustainable Rural Communities Initiative, Oregon State University, Corvallis, Oregon correspondence to Roger B. Hammer, Department of Sociology, Sustainable Rural Communities Initiative, Oregon the retirement of the baby boom generation to exacerbate these trends. Keywords demographic trends, wicked

  3. Active Ageing Roadmap A collaborative Networks Contribution to Demographic Sustainability

    E-print Network

    Boyer, Edmond

    the understanding of ageing and retirement, and questioning elderly's work, happiness, leisure, communityActive Ageing Roadmap ­ A collaborative Networks Contribution to Demographic Sustainability Luis M and potential of retired or retiring senior professionals. As such, collaborative networks can contribute

  4. Clinical features of symptomatic patellofemoral joint osteoarthritis

    PubMed Central

    2012-01-01

    Introduction Patellofemoral joint osteoarthritis (OA) is common and leads to pain and disability. However, current classification criteria do not distinguish between patellofemoral and tibiofemoral joint OA. The objective of this study was to provide empirical evidence of the clinical features of patellofemoral joint OA (PFJOA) and to explore the potential for making a confident clinical diagnosis in the community setting. Methods This was a population-based cross-sectional study of 745 adults aged ?50 years with knee pain. Information on risk factors and clinical signs and symptoms was gathered by a self-complete questionnaire, and standardised clinical interview and examination. Three radiographic views of the knee were obtained (weight-bearing semi-flexed posteroanterior, supine skyline and lateral) and individuals were classified into four subsets (no radiographic OA, isolated PFJOA, isolated tibiofemoral joint OA, combined patellofemoral/tibiofemoral joint OA) according to two different cut-offs: 'any OA' and 'moderate to severe OA'. A series of binary logistic and multinomial regression functions were performed to compare the clinical features of each subset and their ability in combination to discriminate PFJOA from other subsets. Results Distinctive clinical features of moderate to severe isolated PFJOA included a history of dramatic swelling, valgus deformity, markedly reduced quadriceps strength, and pain on patellofemoral joint compression. Mild isolated PFJOA was barely distinguished from no radiographic OA (AUC 0.71, 95% CI 0.66, 0.76) with only difficulty descending stairs and coarse crepitus marginally informative over age, sex and body mass index. Other cardinal signs of knee OA - the presence of effusion, bony enlargement, reduced flexion range of movement, mediolateral instability and varus deformity - were indicators of tibiofemoral joint OA. Conclusions Early isolated PFJOA is clinically manifest in symptoms and self-reported functional limitation but has fewer clear clinical signs. More advanced disease is indicated by a small number of simple-to-assess signs and the relative absence of classic signs of knee OA, which are predominantly manifestations of tibiofemoral joint OA. Confident diagnosis of even more advanced PFJOA may be limited in the community setting. PMID:22417687

  5. [Integration of demographic variables into development plans in the Sahel].

    PubMed

    Wane, H R

    1992-07-01

    A founding principle of the Program of Action of N'Djamena is the interdependence of population and development and the need for development strategies to take demographic factors into account. The concept of integration of population variables into development has evolved since its introduction in the 1974 World Population Plan of Action from a simple description of population size, growth rates, and distribution to a stress on harmonizing population policies and development policies with macroeconomic variables. The essence of the concept is the consideration given by development policies and programs to the interrelations between population, resources, the environment, and development factors. Population variables and goals should ideally be treated as endogenous variables in development planning, but in practice the extreme complexity of such a systematic approach limits its ability to be made operational. Usually the most crucial problems only are included. Integrated planning is composed of explicit or implicit population policies intended to influence demographic variables and of socioeconomic policies intended to adapt to demographic change. In the Sahel, only Senegal, Burkina Faso, and Mali have formal population policies, but around 1980 several countries of the region began to show interest in influencing demographic variables as they did economic variables. Fundamental principles for developing an integration strategy can be applied regardless or whether the plan is based on projections, analysis of interaction of a demographic variable with factors specific to a sector, or a monosectorial or multisectorial demoeconomic planning model. Demographic data is used more frequently in diagnosing problems than in developing projections or formulating objectives. The level of disaggregation of demographic projections and estimates tends to be low, despite the great potential utility of demographic projections in planning. Demographic projections can be useful in analyses of the extent of changes and the implications of alternative scenarios of development planning. The most frequently used demographic variables in development planning have been spatial distribution of the population and mortality. An examination of past development plans in Mali relating to population and nutrition and population and health reveals several inconsistencies between stated goals and strategies intended to achieve them. The incoherence can be explained in part by the absence of a coherent national population policy, the failure to translate the population policy into programs that take into account reciprocal effects of demographic trends and economic perspectives and their social effects, and the absence of disaggregated population projections. An example from Senegal demonstrates the constraints imposed by structural adjustment programs on the entire planning process. PMID:12344768

  6. Patterns, Drivers and Implications of Demographic Change in Rural Landscapes

    Microsoft Academic Search

    Digby Race; Gary W. Luck; Rosemary Black

    \\u000a The movement of people to reside in new locations – a key aspect of demographic change – is a phenomenon Australia shares\\u000a with the rest of the world. While most of Australia’s population lives in an urban environment, the dimensions of demographic\\u000a change are more complex than a steady leakage of rural people to the cities. There is a simultaneous

  7. Simulating the effect of demographic events on the household composition

    Microsoft Academic Search

    Keith Spicer; Ian Diamond; Maire Ni Bhrolchain

    1992-01-01

    The aim of this paper is to measure the effects on household composition of changes in demographic events, e.g. mortality,\\u000a fertility, marriage, divorce. British household data are taken from the General Household Survey and aged by simulation to\\u000a 2001 using a ‘Most Likely’ model. Subsequently different assumptions of each demographic event are taken from 1991 so that\\u000a the effects of

  8. Robotic Bladder Joint

    NASA Technical Reports Server (NTRS)

    Robertson, Glen A.

    1995-01-01

    Reliable, lightweight robotic joint suitable for variety of applications, actuated hydraulically, without need for heavy mechanical cylinders or gears on joint itself. Includes two members; first member rotates about pin at end of second member. Includes cam, over which tension line stretched. Ends of tension line anchored at end of second member opposite end that holds pin. Bladder placed on each side of second member, squeezed between second member and tension line. Pressures and/or amounts of fluid in bladders controlled by use of conventional equipment like pumps, valves, and reservoirs. Bladder on one side inflated more than on other side; greater inflation on one side causes greater stretching of tension line on that side. Greater tension pulls on cam, turning first member toward that side. Angle of joint controlled by controlling differential inflation of two bladders.

  9. The Joint Confidence Level Paradox: A History of Denial

    NASA Technical Reports Server (NTRS)

    Butts, Glenn; Linton, Kent

    2009-01-01

    This paper is intended to provide a reliable methodology for those tasked with generating price tags on construction (C0F) and research and development (R&D) activities in the NASA performance world. This document consists of a collection of cost-related engineering detail and project fulfillment information from early agency days to the present. Accurate historical detail is the first place to start when determining improved methodologies for future cost and schedule estimating. This paper contains a beneficial proposed cost estimating method for arriving at more reliable numbers for future submits. When comparing current cost and schedule methods with earlier cost and schedule approaches, it became apparent that NASA's organizational performance paradigm has morphed. Mission fulfillment speed has slowed and cost calculating factors have increased in 21st Century space exploration.

  10. Quick acting gimbal joint

    NASA Technical Reports Server (NTRS)

    Wood, William B. (inventor); Krch, Gary D. (inventor)

    1993-01-01

    The present invention relates to an adjustable linkage assembly for selectively retaining the position of one member pivotable with respect to another member. More specifically, the invention relates to a linkage assembly commonly referred to as a gimbal joint, and particularly to a quick release or quick acting gimbal joint. The assembly is relatively simple in construction, compact in size, and has superior locking strength in any selected position. The device can be quickly and easily actuated, without separate tooling, by inexperienced personnel or by computer controlled equipment. It also is designed to prevent inadvertent actuation.

  11. Joint for deployable structures

    NASA Technical Reports Server (NTRS)

    Craighead, N. D., II; Preliasco, R. J.; Hult, T. D. (inventors)

    1985-01-01

    A joint is described for connecting a pair of beams to pivot them between positions in alignment or beside one another, which is of light weight and which operates in a controlled manner. The joint includes a pair of fittings and at least one center link having opposite ends pivotally connected to opposite fittings and having axes that pass through centerplates of the fittings. A control link having opposite ends pivotally connected to the different fittings controls their relative orientations, and a toggle assemly holds the fittings in the deployed configuration wherein they are aligned. The fittings have stops that lie on one side of the centerplane opposite the toggle assembly.

  12. Prosthetic Joint Infection

    PubMed Central

    Tande, Aaron J.

    2014-01-01

    SUMMARY Prosthetic joint infection (PJI) is a tremendous burden for individual patients as well as the global health care industry. While a small minority of joint arthroplasties will become infected, appropriate recognition and management are critical to preserve or restore adequate function and prevent excess morbidity. In this review, we describe the reported risk factors for and clinical manifestations of PJI. We discuss the pathogenesis of PJI and the numerous microorganisms that can cause this devastating infection. The recently proposed consensus definitions of PJI and approaches to accurate diagnosis are reviewed in detail. An overview of the treatment and prevention of this challenging condition is provided. PMID:24696437

  13. Prosthetic joint infection.

    PubMed

    Tande, Aaron J; Patel, Robin

    2014-04-01

    Prosthetic joint infection (PJI) is a tremendous burden for individual patients as well as the global health care industry. While a small minority of joint arthroplasties will become infected, appropriate recognition and management are critical to preserve or restore adequate function and prevent excess morbidity. In this review, we describe the reported risk factors for and clinical manifestations of PJI. We discuss the pathogenesis of PJI and the numerous microorganisms that can cause this devastating infection. The recently proposed consensus definitions of PJI and approaches to accurate diagnosis are reviewed in detail. An overview of the treatment and prevention of this challenging condition is provided. PMID:24696437

  14. Origin and demographic history of the endemic Taiwan spruce (Picea morrisonicola)

    PubMed Central

    Bodare, Sofia; Stocks, Michael; Yang, Jeng-Chuann; Lascoux, Martin

    2013-01-01

    Taiwan spruce (Picea morrisonicola) is a vulnerable conifer species endemic to the island of Taiwan. A warming climate and competition from subtropical tree species has limited the range of Taiwan spruce to the higher altitudes of the island. Using seeds sampled from an area in the central mountain range of Taiwan, 15 nuclear loci were sequenced in order to measure genetic variation and to assess the long-term genetic stability of the species. Genetic diversity is low and comparable to other spruce species with limited ranges such as Picea breweriana, Picea chihuahuana, and Picea schrenkiana. Importantly, analysis using approximate Bayesian computation (ABC) provides evidence for a drastic decline in the effective population size approximately 0.3–0.5 million years ago (mya). We used simulations to show that this is unlikely to be a false-positive result due to the limited sample used here. To investigate the phylogenetic origin of Taiwan spruce, additional sequencing was performed in the Chinese spruce Picea wilsonii and combined with previously published data for three other mainland China species, Picea purpurea, Picea likiangensis, and P. schrenkiana. Analysis of population structure revealed that P. morrisonicola clusters most closely with P. wilsonii, and coalescent analyses using the program MIMAR dated the split to 4–8 mya, coincidental to the formation of Taiwan. Considering the population decrease that occurred after the split, however, led to a much more recent origin. PMID:24223271

  15. Phylogeography and Demographic History of Amblyomma variegatum (Fabricius) (Acari: Ixodidae), the Tropical Bont Tick

    PubMed Central

    Patel, Jaymin; Lucas-Williams, Helene; Adakal, Hassane; Kanduma, Esther G.; Tembo-Mwase, Enala; Krecek, Rosina; Mertins, James W.; Alfred, Jeffery T.; Kelly, Susyn; Kelly, Patrick

    2012-01-01

    Abstract The genetic diversity of Amblyomma variegatum (Fabricius) from four Caribbean islands and five African countries was compared by analyzing the sequences of three gene fragments, two mitochondrial (12SrDNA and D-Loop-DL), and one nuclear (intergenic transcribed spacer 2 [ITS2]). Genetic variability of the ITS2 DNA fragment consisted of only uninformative single nucleotide mutations, and therefore this gene was excluded from further analyses. Mitochondrial gene divergences among African populations and between Caribbean and African populations were very low. Nevertheless, the data suggest that A. variegatum is divided into distinct East and West African groups, the western group including all Caribbean samples. Phylogenetic analyses of the 12SrDNA and DL gene sequences showed that the West African A. variegatum clustered in a well-supported monophyletic clade, distinct from eastern paraphyletic lineages. Sequences of A. variegatum from the Caribbean were embedded in the West African clade, which supports the known West African historical origin for these ticks. PMID:22448720

  16. The National Lung Screening Trial: Results Stratified by Demographics, Smoking History and Lung Cancer Histology

    PubMed Central

    Pinsky, Paul F.; Church, Timothy R.; Izmirlian, Grant; Kramer, Barnett S.

    2013-01-01

    Background The National Lung Screening Trial (NLST), which compared lung cancer screening with low-dose CT (LDCT) versus chest radiograph (CXR), demonstrated a statistically significant mortality benefit of LDCT screening. We performed a post-hoc analysis to examine whether the benefit was affected by various baseline factors, including age, gender and smoking status, and whether it differed by histology. Methods Lung cancer death rates were computed as events over person years of observation; the mortality risk ratio (RR) was defined as the lung cancer death rate in the LDCT versus CXR arm. Poisson regression was used to test for interactions of gender, age (<65 versus 65+) and smoking status (current versus former) with trial arm. Mortality risk ratios were also computed for specific lung cancer histologies. Results The overall mortality RR was 0.92 in men and 0.73 in women, with a p-value for interaction of 0.08. RRs were similar for subjects under age 65 (0.82) versus 65+ (0.87), and for current (0.81) versus former smokers (0.91). By histology, mortality RRs were 0.75 for adenocarcinoma, 0.71 for all non small cell lung cancer (NSCLC) except squamous, 1.23 for squamous cell carcinoma, and 0.90 for small cell carcinoma. RRs were similar for men and women for non-squamous NSCLC, 0.71 and 0.70, respectively; women had lower RRs for small cell and squamous cell carcinoma. Conclusions LDCT benefit did not vary substantially by age or smoking status; there was weak evidence of differential benefit by gender. Differential benefit across lung cancer histologies may exist. PMID:24037918

  17. Life history strategy in herbaceous perennials: inferring demographic patterns from the aboveground dynamics

    E-print Network

    Shefferson, Richard P.

    for their nutritional requirements, especially carbon. Because green plants sprout both to photosynthesize always lead to flowering in a ten-year monitoring study of a myco-heterotrophic plant, the autumn coral. Plants typically flowered and fruited when they sprouted (flowering frequency 0.99), supporting our first

  18. Phylogeography and Demographic History of Babina pleuraden (Anura, Ranidae) in Southwestern China

    PubMed Central

    Rao, Dingqi; Yang, Junxing

    2012-01-01

    Factors that determine genetic structure of species in southwestern China remain largely unknown. In this study, sequences of two mitochondrial genes (COI and cyt b) were determined to investigate the phylogeography and demography of Babina pleuraden, a pond frog endemic to southwestern China. A total of 262 individuals from 22 populations across the entire range of the species were collected. Our results indicate that B. pleuraden comprises five well-supported mitochondrial lineages roughly corresponding to five geographical areas. The phylogeographic structure of B. pleuraden has been shaped primarily by the unique regional responses of the Yunnan Plateau to the rapid uplift of the Qinghai-Tibetan Plateau occurred c. 2.5 Mya (B phrase of Qingzang Movement) and climatic oscillation during middle Pleistocene (c. 0.64–0.36 Mya), rather than by the paleo-drainage systems. The present wide distribution of the species has resulted from recent population expansion (c. 0.053–0.025 Mya) from multiple refugia prior to the Last Glacial Maximum, corresponding to the scenario of “refugia within refugia”. PMID:22448286

  19. Complex population genetic and demographic history of the Salangid, Neosalanx taihuensis, based on cytochrome b sequences

    Microsoft Academic Search

    Liang Zhao; Jie Zhang; Zhijin Liu; Stephan M Funk; Fuwen Wei; Muqi Xu; Ming Li

    2008-01-01

    BACKGROUND: The Salangid icefish Neosalanx taihuensis (Salangidae) is an economically important fish, which is endemic to China, restricted to large freshwater systems (e.g. lakes, large rivers and estuaries) and typically exhibit low vagility. The continuous distribution ranges from the temperate region of the Huai and Yellow River basins to the subtropical region of the Pearl River basin. This wide ranging

  20. Gene flow and demographic history of leopards (Panthera pardus) in the central Indian highlands

    PubMed Central

    Dutta, Trishna; Sharma, Sandeep; Maldonado, Jesús E; Wood, Thomas C; Panwar, Hemendra S; Seidensticker, John

    2013-01-01

    Gene flow is a critical ecological process that must be maintained in order to counteract the detrimental effects of genetic drift in subdivided populations, with conservation benefits ranging from promoting the persistence of small populations to spreading adaptive traits in changing environments. We evaluated historical and contemporary gene flow and effective population sizes of leopards in a landscape in central India using noninvasive sampling. Despite the dramatic changes in land-use patterns in this landscape through recent times, we did not detect any signs that the leopard populations have been through a genetic bottleneck, and they appear to have maintained migration–drift equilibrium. We found that historical levels of gene flow (mean mh = 0.07) were significantly higher than contemporary levels (mean mc = 0.03), and populations with large effective population sizes (Satpura and Kanha Tiger Reserves) are the larger exporters of migrants at both timescales. The greatest decline in historical versus contemporary gene flow is between pairs of reserves that are currently not connected by forest corridors (i.e., Melghat-Pench mh ? mc = 0.063; and Kanha-Satpura mh ? mc = 0.054). We attribute this reduction in gene flow to accelerated fragmentation and habitat alteration in the landscape over the past few centuries, and suggest protection of forest corridors to maintain gene flow in this landscape. PMID:24062803

  1. The effects of Medieval dams on genetic divergence and demographic history in brown trout populations

    PubMed Central

    2014-01-01

    Background Habitat fragmentation has accelerated within the last century, but may have been ongoing over longer time scales. We analyzed the timing and genetic consequences of fragmentation in two isolated lake-dwelling brown trout populations. They are from the same river system (the Gudenĺ River, Denmark) and have been isolated from downstream anadromous trout by dams established ca. 600–800 years ago. For reference, we included ten other anadromous populations and two hatchery strains. Based on analysis of 44 microsatellite loci we investigated if the lake populations have been naturally genetically differentiated from anadromous trout for thousands of years, or have diverged recently due to the establishment of dams. Results Divergence time estimates were based on 1) Approximate Bayesian Computation and 2) a coalescent-based isolation-with-gene-flow model. Both methods suggested divergence times ca. 600–800 years bp, providing strong evidence for establishment of dams in the Medieval as the factor causing divergence. Bayesian cluster analysis showed influence of stocked trout in several reference populations, but not in the focal lake and anadromous populations. Estimates of effective population size using a linkage disequilibrium method ranged from 244 to?>?1,000 in all but one anadromous population, but were lower (153 and 252) in the lake populations. Conclusions We show that genetic divergence of lake-dwelling trout in two Danish lakes reflects establishment of water mills and impassable dams ca. 600–800 years ago rather than a natural genetic population structure. Although effective population sizes of the two lake populations are not critically low they may ultimately limit response to selection and thereby future adaptation. Our results demonstrate that populations may have been affected by anthropogenic disturbance over longer time scales than normally assumed. PMID:24903056

  2. Life history analysis for black bears ( Ursus americanus) in a changing demographic landscape

    Microsoft Academic Search

    Adam H. Freedman; Kenneth M. Portier; Melvin E. Sunquist

    2003-01-01

    We used matrix population models to evaluate the relative importance of different vital rates to population growth (?) for female black bears on the Southeastern Coastal Plain (SCP) of the United States, and to determine whether reductions in subadult and adult survival due to ongoing habitat fragmentation and human disturbance will cause shifts in the relative importance of vital rates.

  3. Genetic Diversity and Demographic History of Cajanus spp. Illustrated from Genome-Wide SNPs

    PubMed Central

    Saxena, Rachit K.; von Wettberg, Eric; Upadhyaya, Hari D.; Sanchez, Vanessa; Songok, Serah; Saxena, Kulbhushan; Kimurto, Paul; Varshney, Rajeev K.

    2014-01-01

    Understanding genetic structure of Cajanus spp. is essential for achieving genetic improvement by quantitative trait loci (QTL) mapping or association studies and use of selected markers through genomic assisted breeding and genomic selection. After developing a comprehensive set of 1,616 single nucleotide polymorphism (SNPs) and their conversion into cost effective KASPar assays for pigeonpea (Cajanus cajan), we studied levels of genetic variability both within and between diverse set of Cajanus lines including 56 breeding lines, 21 landraces and 107 accessions from 18 wild species. These results revealed a high frequency of polymorphic SNPs and relatively high level of cross-species transferability. Indeed, 75.8% of successful SNP assays revealed polymorphism, and more than 95% of these assays could be successfully transferred to related wild species. To show regional patterns of variation, we used STRUCTURE and Analysis of Molecular Variance (AMOVA) to partition variance among hierarchical sets of landraces and wild species at either the continental scale or within India. STRUCTURE separated most of the domesticated germplasm from wild ecotypes, and separates Australian and Asian wild species as has been found previously. Among Indian regions and states within regions, we found 36% of the variation between regions, and 64% within landraces or wilds within states. The highest level of polymorphism in wild relatives and landraces was found in Madhya Pradesh and Andhra Pradesh provinces of India representing the centre of origin and domestication of pigeonpea respectively. PMID:24533111

  4. Low worldwide genetic diversity in the killer whale (Orcinus orca): implications for demographic history.

    PubMed Central

    Hoelzel, A Rus; Natoli, Ada; Dahlheim, Marilyn E; Olavarria, Carlos; Baird, Robin W; Black, Nancy A

    2002-01-01

    A low level of genetic variation in mammalian populations where the census population size is relatively large has been attributed to various factors, such as a naturally small effective population size, historical bottlenecks and social behaviour. The killer whale (Orcinus orca) is an abundant, highly social species with reduced genetic variation. We find no consistent geographical pattern of global diversity and no mtDNA variation within some regional populations. The regional lack of variation is likely to be due to the strict matrilineal expansion of local populations. The worldwide pattern and paucity of diversity may indicate a historical bottleneck as an additional factor. PMID:12137576

  5. Gene flow and demographic history of leopards (Panthera pardus) in the central Indian highlands.

    PubMed

    Dutta, Trishna; Sharma, Sandeep; Maldonado, Jesús E; Wood, Thomas C; Panwar, Hemendra S; Seidensticker, John

    2013-09-01

    Gene flow is a critical ecological process that must be maintained in order to counteract the detrimental effects of genetic drift in subdivided populations, with conservation benefits ranging from promoting the persistence of small populations to spreading adaptive traits in changing environments. We evaluated historical and contemporary gene flow and effective population sizes of leopards in a landscape in central India using noninvasive sampling. Despite the dramatic changes in land-use patterns in this landscape through recent times, we did not detect any signs that the leopard populations have been through a genetic bottleneck, and they appear to have maintained migration-drift equilibrium. We found that historical levels of gene flow (mean m h = 0.07) were significantly higher than contemporary levels (mean m c = 0.03), and populations with large effective population sizes (Satpura and Kanha Tiger Reserves) are the larger exporters of migrants at both timescales. The greatest decline in historical versus contemporary gene flow is between pairs of reserves that are currently not connected by forest corridors (i.e., Melghat-Pench m h - m c = 0.063; and Kanha-Satpura m h - m c = 0.054). We attribute this reduction in gene flow to accelerated fragmentation and habitat alteration in the landscape over the past few centuries, and suggest protection of forest corridors to maintain gene flow in this landscape. PMID:24062803

  6. Demographic history of Canary Islands male gene-pool: replacement of native lineages by European

    PubMed Central

    Fregel, Rosa; Gomes, Verónica; Gusmăo, Leonor; González, Ana M; Cabrera, Vicente M; Amorim, António; Larruga, Jose M

    2009-01-01

    Background The origin and prevalence of the prehispanic settlers of the Canary Islands has attracted great multidisciplinary interest. However, direct ancient DNA genetic studies on indigenous and historical 17th–18th century remains, using mitochondrial DNA as a female marker, have only recently been possible. In the present work, the analysis of Y-chromosome polymorphisms in the same samples, has shed light on the way the European colonization affected male and female Canary Island indigenous genetic pools, from the conquest to present-day times. Results Autochthonous (E-M81) and prominent (E-M78 and J-M267) Berber Y-chromosome lineages were detected in the indigenous remains, confirming a North West African origin for their ancestors which confirms previous mitochondrial DNA results. However, in contrast with their female lineages, which have survived in the present-day population since the conquest with only a moderate decline, the male indigenous lineages have dropped constantly being substituted by European lineages. Male and female sub-Saharan African genetic inputs were also detected in the Canary population, but their frequencies were higher during the 17th–18th centuries than today. Conclusion The European colonization of the Canary Islands introduced a strong sex-biased change in the indigenous population in such a way that indigenous female lineages survived in the extant population in a significantly higher proportion than their male counterparts. PMID:19650893

  7. HISTORY OF CONSCIOUSNESS HANDBOOK

    E-print Network

    California at Santa Cruz, University of

    HISTORY OF CONSCIOUSNESS HANDBOOK 2012-2013 #12; 1 to Degree 12 M.A. Degree in History of Consciousness 12 #12; 2 HISTORY OF CONSCIOUSNESS HANDBOOK Welcome to graduate study in the History of Consciousness

  8. New Joint Sealants. Criteria, Design and Materials.

    ERIC Educational Resources Information Center

    Building Research Inst., Inc., Washington, DC.

    Contents include--(1) sealing concrete joints, (2) sealing glass and metal joints, (3) metal and glass joint sealants from a fabricator's viewpoint, (4) a theory of adhesion for joint sealants, (5) geometry of simple joint seals under strain, (6) joint sealant specifications from a manufacturer's viewpoint, (7) joint sealant requirements from an…

  9. Personal Health History Name: _____________________________________________________________________________________________

    E-print Network

    Goodman, Robert M.

    _________________________________________________ __________ _________________________________________________ __________ Mental illnesses Year diagnosedActivity 2 Personal Health History Name: ________________________________________ Ethnicity: _________________________________ Medical History: Previous operations Year Hospital

  10. Cygnus History

    SciTech Connect

    David J. Henderson, Raymond E. Gignac, Douglas E. Good, Mark D. Hansen, Charles V. Mitton; Daniel S. Nelson, Eugene C. Ormond; Steve R. Cordova, Isidro Molina; John R. Smith, Evan A. Rose

    2009-07-02

    The Cygnus Dual Beam Radiographic Facility consists of two identical radiographic sources: Cygnus 1 and Cygnus 2. This Radiographic Facility is located in an underground tunnel test area at the Nevada Test Site. The sources were developed to produce high-resolution images for dynamic plutonium experiments. This work will recount and discuss salient maintenance and operational issues encountered during the history of Cygnus. A brief description of Cygnus systems and rational for design selections will set the stage for this historical narrative. It is intended to highlight the team-derived solutions for technical problems encountered during extended periods of maintenance and operation. While many of the issues are typical to pulsed power systems, some of the solutions are unique. It is hoped that other source teams will benefit from this presentation, as well as other necessary disciplines (e.g., source users, system architects, facility designers and managers, funding managers, and team leaders).

  11. Thanksgiving History

    NSDL National Science Digital Library

    Located at the Plimoth Plantation Web site, this collection of material related to the First Thanksgiving will be of great interest to those seeking to learn more about the facts and myths surrounding this famous event in American history. While most of the factual information about this meal comes from first-hand accounts written by William Bradford and Edward Winslow, these accounts are best understood by also studying household traditions, cooking techniques, and religious practices. The site consists primarily of brief essays that elucidate these various nuances of this legendary meal, including pieces on who exactly was in attendance at the 1621 First Thanksgiving, first-hand accounts about the meal, the bill of fare at the meal, and a piece that dispels the popular myth that popcorn was served at this meal. Perhaps the best part of the site are the modern recipe equivalents for the dishes served at the First Thanksgiving, including roast fowl, seethed cod, and hominy pudding.

  12. Moving History

    NSDL National Science Digital Library

    While it took many decades for some skeptics to realize the importance of maintaining archives devoted to preserving film and television programs, the movement has certainly gained a critical mass of interested organizations in recent years. One particularly nice online resource for such matters is the Moving History website, which serves as a research guide to the United Kingdomâ??s twelve public sector film archives. With support from Britainâ??s Arts and Humanities Research Council, the site includes sections that describe each of the collections, along with a lovely selection of 100 film clips. The clips can be browsed by theme and host archive, and they include depictions of British â??holiday-makingâ?ť trips and segments from the popular British television series, â??Steptoe and Sonâ?ť. The site is rounded out by the inclusion of a set of links to related organizations, such as the Association of Moving Image Archivists and the British PathĂ© Film Archive.

  13. Harlem History

    NSDL National Science Digital Library

    Beyond a shadow of a doubt, Harlem is perhaps the most famous African-American neighborhood in the United States (though over history it has been host to a number of ethnic groups), and hundreds of its residents have gone on to major positions of prominence in politics, the arts, and a host of other areas. This multimedia website, designed by the Columbia University Digital Knowledge Ventures group (in conjunction with The Institute for Research in African-American Studies) brings together a number of archival highlights and scholarship from a number of sources at Columbia University. The thematic areas on the site include "Arts and Culture", "The Neighborhood" and "Politics". Visitors can delve into each of these areas and read essays on the architecture and growth of Harlem, its former Jewish identity, and the recollections of the famed labor leader A. Philip Randolph. Finally, the site also contains a number of photo essays of note.

  14. Department of History Teaching Minor in History

    E-print Network

    Vonessen, Nikolaus

    Department of History Teaching Minor in History Students interested in earning a teaching minor in history must complete the following requirements: 4 credits HSTR 101 or 102 European Civilization ________ 8 credits HSTA 101 and 102 American History ________ 1 credit HSTR 200 Introduction to Historical

  15. Joints in a Cornstarch Analog

    NSDL National Science Digital Library

    Juliet Crider

    Joints are very important to problems in applied geology (fluid flow, slope stability), but three-dimensional exposures of simple joint sets are not readily accessible from my campus. I developed this exercise based on the experiments of Miller (2001) to give students hands-on practice describing and interpreting joints. For the exercise, I prepare a cornstarch-water mixture a few days in advance and pour it into plastic petri dishes. I add a "flaw" to each dish (typically a small pebble). As the cornstarch dries, vertical joints develop. In class, each group of 3-4 students is provided a petri dish of desiccated cornstarch. Students are asked to draw a map of the joints, paying particular attention to intersection angles. (The joints curve to intersect at 90 degrees.) They determine relative ages of the joints using abutting relationships. (Typically 3-6 generations of joints.) Students next dissect the sample and describe the surface textures of the larger joints and the location of the flaw. The cornstarch produces beautiful plumose structure (hackles). Students then interpret the joint propagation direction from the surface textures, and note the origin of the joint. (Typically, a first- or second-generation joint initiates at the flaw.) Students discuss the role of flaws in the initiation of joints in their groups.

  16. CARTILAGE, BONES, AND JOINTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cartilage is a special type of connective tissue that is of extreme importance in embryonic development, serving as the model upon which true bone is later formed. Cartilage also persists in adult animals, primarily as articular cartilage which cushions the interface between adjacent bones or joint...

  17. Evolving flexible joint morphologies

    Microsoft Academic Search

    Jared M. Moore; Philip K. McKinley

    2012-01-01

    Transferring virtual robotic designs into physical robots has become possible with the development of 3D printers. Accurately simulating the performance of real robots in a virtual environment requires modeling a variety of conditions, including the physical composition of the robots themselves. In this paper, we investigate how modeling material flexibility through the use of a passive joint affects the resulting

  18. Biologics — beyond the joints

    Microsoft Academic Search

    Zoltán Szekanecz; Sándor Szántó; Zoltán Szabó; Andrea Váncsa; Szilvia Szamosi; Nóra Bodnár; Gabriella Szücs

    2010-01-01

    Biologics including tumor necrosis factor ? (TNF-?), interleukin-6 receptor (IL-6R), T and B cell inhibitors are very effective therapeutic agents for the treatment of arthritides. These compounds effectively improve articular symptoms and inhibit joint damage. In this respect, there are no major differences in the efficacy of the available biologics. However, many arthritis patients also exert extra-articular features, systemic manifestations

  19. Dolphin Skeleton (Gliding Joint)

    NSDL National Science Digital Library

    Ketan Patel (California State University, Fullerton; )

    2007-07-14

    The dolphin is built to be sleek. Its body is made of almost entirely backbone (a gliding joint) which makes it very flexible under water. The ribs protect the inner organs of the dolphin and the tail beats from side to side, thrusting the animal forward.

  20. LARP Joint IR studies

    E-print Network

    Zlobin, A V

    2008-01-01

    LARP initiated Joint IR Studies (JIRS) in October 2007 (FY2008) to coordinate efforts related to the LHC Phase I and II upgrades previously situated either in Accelerator Systems or in Magnet Systems. This note outlines JIRS goals, main directions and milestones.

  1. Implications of ecological energetics and biophysical and developmental constraints for life history variation in dinosaurs

    SciTech Connect

    Dunham, A.E.; Overall, K.L.; Forster, C.A.; Porter, W.P.

    1988-01-01

    There has been much recent speculation concerning the nature of life history variation in dinosaurs (Case, 1978; Bakker, 1986; Horner, 1982, 1984a). The purpose of this paper is to review the data on dinosaur life histories and to examine the nature and magnitude of the demographic and physiological factors that must have constrained life history variation in this group. 145 refs., 8 figs., 3 tabs.

  2. An Exploratory Examination of the Association Between Altered Lumbar Motor Control, Joint Mobility and Low Back Pain in Athletes

    PubMed Central

    Corkery, Marie B.; O’Rourke, Brittany; Viola, Samantha; Yen, Sheng-Che; Rigby, Joseph; Singer, Kevin; Thomas, Adam

    2014-01-01

    Background: Low back pain (LBP) is a common cause of lost playing time and can be a challenging clinical condition in competitive athletes. LBP in athletes may be associated with joint and ligamentous hypermobility and impairments in activation and coordination of the trunk musculature, however there is limited research in this area. Objectives: To determine if there is an association between altered lumbar motor control, joint mobility and low back pain (LBP) in a sample of athletes. Materials and Methods: Fifteen athletes with LBP were matched by age, gender and body mass index (BMI) with controls without LBP. Athletes completed a questionnaire with questions pertaining to demographics, activity level, medical history, need to self-manipulate their spine, pain intensity and location. Flexibility and lumbar motor control were assessed using: active and passive straight leg raise, lumbar range of motion (ROM), hip internal rotation ROM (HIR), Beighton ligamentous laxity scale, prone instability test (PIT), observation of lumbar aberrant movements, double leg lowering and Trendelenburg tests. Descriptive statistics were compiled and the chi square test was used to analyze results. Results: Descriptive statistics showed that 40% of athletes with LBP exhibited aberrant movements (AM), compared to 6% without LBP. 66% of athletes with LBP reported frequently self-manipulating their spine compared to 40% without LBP. No significant differences in motor control tests were found between groups. Athletes with LBP tended to have less lumbar flexion (63 ± 11°) compared to those without LBP (66 ± 13°). Chi-Square tests revealed that the AM were more likely to be present in athletes with LBP than those without (X2 = 4.66, P = 0.03). Conclusions: The presence of aberrant movement patterns is a significant clinical finding and associated with LBP in athletes. PMID:25741418

  3. Assessing population viability while accounting for demographic and environmental uncertainty.

    PubMed

    Oppel, Steffen; Hilton, Geoff; Ratcliffe, Norman; Fenton, Calvin; Daley, James; Gray, Gerard; Vickery, Juliet; Gibbons, David

    2014-07-01

    Predicting the future trend and viability of populations is an essential task in ecology. Because many populations respond to changing environments, uncertainty surrounding environmental responses must be incorporated into population assessments. However, understanding the effects of environmental variation on population dynamics requires information on several important demographic parameters that are often difficult to estimate. Integrated population models facilitate the integration of time series data on population size and all existing demographic information from a species, allowing the estimation of demographic parameters for which limited or no empirical data exist. Although these models are ideal for assessments of population viability, they have so far not included environmental uncertainty. We incorporated environmental variation in an integrated population model to account for both demographic and environmental uncertainty in an assessment of population viability. In addition, we used this model to estimate true juvenile survival, an important demographic parameter for population dynamics that is difficult to estimate empirically. We applied this model to assess the past and future population trend of a rare island endemic songbird, the Montserrat Oriole Icterus oberi, which is threatened by volcanic activity. Montserrat Orioles experienced lower survival in years with volcanic ashfall, causing periodic population declines that were compensated by higher seasonal fecundity in years with high pre-breeding season rainfall. Due to the inclusion of both demographic and environmental uncertainty in the model, the estimated population growth rate in the immediate future was highly imprecise (95% credible interval 0.844-1.105), and the probability of extinction after three generations (in the year 2028) was low (2.1%). This projection demonstrates that accounting for both demographic and environmental sources of uncertainty provides a more realistic assessment of the viability of populations under unknown future environmental conditions. PMID:25163115

  4. Dual-Eccentric Clevis Joint

    NASA Technical Reports Server (NTRS)

    Fairbank, Diana L.; Sertich, John J.

    1996-01-01

    Redesigned clevis joint incorporates dual mating eccentric cylindrical bushings to accommodate dimensional tolerances. Eliminates need for combination of oppositely threaded collar and bushing and makes overall joint hardware fit within available space.

  5. Engineering Alloplastic Temporomandibular Joint Replacements

    PubMed Central

    Sinno, Hani; Tahiri, Youssef; Gilardino, Mirko; Bobyn, Dennis

    2011-01-01

    Temporomandibular disorders (TMD) are part of a heterogeneous group of pathologies that manifest with a constellation of signs and symptoms. They are the most frequent cause of chronic orofacial pain and are prevalent in 12% of the general population. Despite the debilitating nature of these disorders, there is no standardization for treatment of the diseased temporomandibular joint (TMJ). In this review, we present an overview of the functional anatomy of the TMJ and the engineering concepts that must be understood to better understand the indications for surgical management, the types of available treatments and the requirements for reconstruction. A comparison is made of the clinical outcomes with autogenous versus alloplastic reconstruction, including a history of alloplastic materials and the design features of currently available implants. Emphasis is made on material selection, modulus, stiffness, notch sensitivity and modularity. For the treatment of TMD, engineered TMJ alloplastic replacements have had considerable promise with additional room for improvement using new materials and recent design concepts. PMID:22363183

  6. Determination of Parachute Joint Factors using Seam and Joint Testing

    NASA Technical Reports Server (NTRS)

    Mollmann, Catherine

    2015-01-01

    This paper details the methodology for determining the joint factor for all parachute components. This method has been successfully implemented on the Capsule Parachute Assembly System (CPAS) for the NASA Orion crew module for use in determining the margin of safety for each component under peak loads. Also discussed are concepts behind the joint factor and what drives the loss of material strength at joints. The joint factor is defined as a "loss in joint strength...relative to the basic material strength" that occurs when "textiles are connected to each other or to metals." During the CPAS engineering development phase, a conservative joint factor of 0.80 was assumed for each parachute component. In order to refine this factor and eliminate excess conservatism, a seam and joint testing program was implemented as part of the structural validation. This method split each of the parachute structural joints into discrete tensile tests designed to duplicate the loading of each joint. Breaking strength data collected from destructive pull testing was then used to calculate the joint factor in the form of an efficiency. Joint efficiency is the percentage of the base material strength that remains after degradation due to sewing or interaction with other components; it is used interchangeably with joint factor in this paper. Parachute materials vary in type-mainly cord, tape, webbing, and cloth -which require different test fixtures and joint sample construction methods. This paper defines guidelines for designing and testing samples based on materials and test goals. Using the test methodology and analysis approach detailed in this paper, the minimum joint factor for each parachute component can be formulated. The joint factors can then be used to calculate the design factor and margin of safety for that component, a critical part of the design verification process.

  7. Cellular Pressure-Actuated Joint

    NASA Technical Reports Server (NTRS)

    McGuire, John R.

    2003-01-01

    A modification of a pressure-actuated joint has been proposed to improve its pressure actuation in such a manner as to reduce the potential for leakage of the pressurizing fluid. The specific joint for which the modification is proposed is a field joint in a reusable solid-fuel rocket motor (RSRM), in which the pressurizing fluid is a mixture of hot combustion gases. The proposed modification could also be applicable to other pressure-actuated joints of similar configuration.

  8. Demographic factors and land-use planning in the small islands of Southern Europe

    NASA Astrophysics Data System (ADS)

    Soliani, Lamberto; Rossi, Orazio

    1992-09-01

    Since the end of the 1970s, the southern European countries have shown an exceptional reduction in fertility rate. From the highest levels among the developed nations, these countries dropped beneath the substitution rate level: in Greece there is an average of about 1.5 children per woman, and Italy (starting three to four years ago), with 1.3 children per woman, is now the country with the lowest fecundity rate in the world. Land-use planning in southern European small islands therefore requires substantial revision. In the areas where western civilization began, which are highly populated and have a long history, cultural and ethnic aspects of tradition are fundamental to environmental management and to the defense of historical heritage. They also place a strong value on sustaining tourism, the most relevant economic activity, that allows them to survive and maintain a high welfare level. For some decades they have had populations with a marked presence of young people and high emigration rates, but now they are fast becoming dominated by the elderly and must prepare for a period of fast reduction in youth of the workforce, while the peripheral areas of Asia and Africa are entering a sudden demographic growth phase. The demographic structure has also been deeply altered both by previous migrations and by random variations, as usually happens in all small communities. Social services for younger and older people have had to be adapted rapidly, reorganizing high-school management, hospital and health-care structures, in-house assistance, and so on. There is a need to rethink the job market and favor the immigration of highly specialized workers, which is a necessity for technical evolution. Sustainable development is constrained nowadays not only by the scarcity of natural resources, but also by the quality and quantity of human resources. Proper policies for population and land-use planning are highly correlated factors; they have to be considered with respect of these new, rapid demographic changes.

  9. Extreme temperature events alter demographic rates, relative fitness, and community structure.

    PubMed

    Ma, Gang; Rudolf, Volker H W; Ma, Chun-Sen

    2015-05-01

    The frequency and magnitude of extreme events are predicted to increase under future climate change. Despite recent advancements, we still lack a detailed understanding of how changes in the frequency and amplitude of extreme climate events are linked to the temporal and spatial structure of natural communities. To answer this question, we used a combination of laboratory experiments, field experiments, and analysis of multi-year field observations to reveal the effects of extreme high temperature events on the demographic rates and relative dominance of three co-occurrence aphid species which differ in their transmission efficiency of different agricultural pathogens. We then linked the geographical shift in their relative dominance to frequent extreme high temperatures through a meta-analysis. We found that both frequency and amplitude of extreme high temperatures altered demographic rates of species. However, these effects were species-specific. Increasing the frequency and amplitude of extreme temperature events altered which species had the highest fitness. Importantly, this change in relative fitness of species was consistent with significant changes in the relative dominance of species in natural communities in a 1 year long field heating experiment and 6 year long field survey of natural populations. Finally, at a global spatial scale, we found the same relationship between relative abundance of species and frequency of extreme temperatures. Together, our results indicate that changes in frequency and amplitude of extreme high temperatures can alter the temporal and spatial structure of natural communities, and that these changes are driven by asymmetric effects of high temperatures on the demographic rates and fitness of species. They also highlight the importance of understanding how extreme events affect the life-history of species for predicting the impacts of climate change at the individual and community level, and emphasize the importance of using a broad range of approaches when studying climate change. PMID:24909842

  10. Joint Seminar Risk Management Institute &

    E-print Network

    Chaudhuri, Sanjay

    Joint Seminar Risk Management Institute & Department of Mathematics Details of Seminar Date empirical phenomena of the negative variance risk premium and implied volatility smirk if market into account. This is a joint work with Eric C. Chang and Huimin Zhao. Risk Management Institute Joint Seminar

  11. Double slotted socket spherical joint

    DOEpatents

    Bieg, Lothar F. (Albuquerque, NM); Benavides, Gilbert L. (Albuquerque, NM)

    2001-05-22

    A new class of spherical joints is disclosed. These spherical joints are capable of extremely large angular displacements (full cone angles in excess of 270.degree.), while exhibiting no singularities or dead spots in their range of motion. These joints can improve or simplify a wide range of mechanical devices.

  12. Phase 1 Program Joint Report

    NASA Technical Reports Server (NTRS)

    Nield, George C. (Editor); Vorobiev, Pavel Mikhailovich (Editor)

    1999-01-01

    This report consists of inputs from each of the Phase I Program Joint Working Groups. The Working Groups were tasked to describe the organizational structure and work processes that they used during the program, joint accomplishments, lessons learned, and applications to the International Space Station Program. This report is a top-level joint reference document that contains information of interest to both countries.

  13. Economical Joint for Truss Structures

    NASA Technical Reports Server (NTRS)

    Moore, Carleton J.

    1987-01-01

    Mass-produced flat parts easily assembled. Joint for three-dimensional truss made of simple die-cutplates and inexpensive fasteners. Each truss joint consists of two identical interlocking plates bolted, welded, or glued together. Truss struts bolted to joint through holes in plate. Alternatively, ends of struts forked so that they slip over plates and fastened to them by bolts or pins.

  14. The Challenges of Joint Attention

    Microsoft Academic Search

    Frederic Kaplan; Verena V. Hafner

    2004-01-01

    This paper discusses the concept of joint at- tention and the dierent skills underlying its development. We argue that joint attention is much more than gaze following or simul- taneous looking because it implies a shared intentional relation to the world. The current state-of-the-art in robotic and computational models of the dierent prerequisites of joint attention is discussed in relation

  15. Inherent demographic stability in mutualist-resource-exploiter interactions.

    PubMed

    Lee, Charlotte T

    2015-04-01

    Core principles of ecological theory predict that, in the absence of other factors, mutualisms should experience destabilizing positive feedback and should be vulnerable to extinction through competitive exclusion by exploiter species. Many effective stabilizing mechanisms address one issue or the other, and many turn upon additional features. Using an explicitly demographic approach, I show that indirect, demography-mediated interactions between mutualists and exploiters can enable mutualist-exploiter coexistence, which in turn can stabilize the abundances of mutualists, exploiters, and their shared resources. This occurs because of the distinct resource demographic responses that are inherent to interaction with mutualistic and exploitative partners and can occur in long-lasting, exclusive interactions, such as protection mutualisms, as well as in apparently very different, short-lived mutualistic interactions, such as pollination. The key necessary factor-demographic response to interspecific interaction-is common in nature. Some demographic structure is also necessary and is generated through interspecific interaction in long-lasting associations; it is also very common in natural populations. Thus, the explicitly demographic and multispecies approach taken here constitutes a potentially promising single explanation for the apparent stability of mutualism in a wide range of natural systems. PMID:25811088

  16. First Person History

    NSDL National Science Digital Library

    Mrs. Merkley

    2007-11-30

    You will choose an event in history to research, and use pictures to provide evidence. 1. Using \\"Hyper History Online\\", \\"American Studies Links\\" and \\"History Matters\\", select an event or person in history (for example, the sinking of the Lusitania or Andrew Jackson). History Matters American Studies Links Recommended by Richard P. Horowitz Hyper History Online 2. Research this person or event using the above resources. 3. Search \\"Images of American Political History\\" for pictures that relate to your ...

  17. Demographic fitness of Belminus ferroae (Hemiptera: Triatominae) on three different hosts under laboratory conditions

    PubMed Central

    Sandoval, Claudia Magaly; Medone, Paula; Nieves, Elsa Evelia; Jaimes, Diego Alexander; Ortiz, Nelcy; Rabinovich, Jorge Eduardo

    2013-01-01

    Triatominae are widely recognised for their role as vectors of Trypanosoma cruzi. One of the main biological characteristics of this subfamily is their obligate haematophagous condition. However, previous studies on Belminus herreri and Belminus ferroae suggested that cockroaches are their principal hosts in domiciles. Due to this peculiar behaviour, the aim of this study was to analyse several demographic and reproductive parameters of B. ferroae fed on three different hosts (mice, cockroaches and Rhodnius prolixus) and relate B. ferroae fitness to these alternative hosts. The cohorts were reared under constant conditions. The egg hatching rate was similar for cohorts fed on cockroaches (69.4%) and R. prolixus (63.8%), but was much lower for the cohort fed on mice (16%). The development time from the nymph to adult stage and the average age of first reproduction (?) presented lower values in the cohort fed on cockroaches, which is consistent with the higher population growth rate associated with this host. Demographic parameters [intrinsic rate of natural increase, finite rate of population growth, net reproductive rate and damping ratio] showed statistically significant differences between the cohorts. Analysis of the life history of B. ferroae revealed a higher fitness related to the cockroach. The implications of these results for the origin of the subfamily are discussed. PMID:24141961

  18. Demographic and clinical characteristics associated with treatment status in family members with obsessive-compulsive disorder.

    PubMed

    Cullen, Bernadette; Samuels, Jack F; Pinto, Anthony; Fyer, Abby J; McCracken, James T; Rauch, Scott L; Murphy, Dennis L; Greenberg, Benjamin D; Knowles, James A; Piacentini, John; Bienvenu, O Joseph; Grados, Marco A; Riddle, Mark A; Rasmussen, Steven A; Pauls, David L; Willour, Virginia L; Shugart, Yin Y; Liang, Kung-Yee; Hoehn-Saric, Rudolf; Nestadt, Gerald

    2008-01-01

    This study investigated the demographic and clinical factors that influence treatment status in family members with obsessive compulsive disorder (OCD). Six hundred and two subjects from the OCD Collaborative Genetics Study were interviewed using the Structured Clinical Interview for DSM-IV (SCID) to diagnose Axis I disorders, and the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) for assessment of OCD symptoms. The demographic and clinical data were compared between subjects who had received treatment and those who had not. A precipitous onset of symptoms, severe illness, multiple obsessions and compulsions, and co-morbid affective disorders were all positively associated with receiving treatment. Older age and the presence of obsessive compulsive personality disorder (OCPD) or OCPD traits were negatively associated with treatment. Gender and age at onset of symptoms did not predict treatment history. The mean duration from onset of symptoms to receiving treatment was 13.8+/-SD 11.9 years, but there was a direct relationship between current age and time to treatment, with younger subjects receiving treatment sooner. Clinical factors are predominant in predicting treatment status in family members with OCD. Although the mean duration from onset of symptoms to treatment was long, younger family members appear to receive treatment sooner. PMID:17345603

  19. 49 CFR 213.121 - Rail joints.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Transportation 4 2011-10-01 2011-10-01 false Rail joints. 213.121 Section 213.121 Transportation...SAFETY STANDARDS Track Structure § 213.121 Rail joints. (a) Each rail joint, insulated joint, and compromise...

  20. 49 CFR 213.121 - Rail joints.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Transportation 4 2014-10-01 2014-10-01 false Rail joints. 213.121 Section 213.121 Transportation...SAFETY STANDARDS Track Structure § 213.121 Rail joints. (a) Each rail joint, insulated joint, and compromise...

  1. 49 CFR 213.121 - Rail joints.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Transportation 4 2012-10-01 2012-10-01 false Rail joints. 213.121 Section 213.121 Transportation...SAFETY STANDARDS Track Structure § 213.121 Rail joints. (a) Each rail joint, insulated joint, and compromise...

  2. 49 CFR 213.121 - Rail joints.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Transportation 4 2010-10-01 2010-10-01 false Rail joints. 213.121 Section 213.121 Transportation...SAFETY STANDARDS Track Structure § 213.121 Rail joints. (a) Each rail joint, insulated joint, and compromise...

  3. 49 CFR 213.121 - Rail joints.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Transportation 4 2013-10-01 2013-10-01 false Rail joints. 213.121 Section 213.121 Transportation...SAFETY STANDARDS Track Structure § 213.121 Rail joints. (a) Each rail joint, insulated joint, and compromise...

  4. Improved high-temperature gimbal joint

    NASA Technical Reports Server (NTRS)

    Winemiller, J. R.; Yee, S. T.; Neal, B. H.

    1972-01-01

    Development and characteristics of bellows gimbal joint for reduction of thermal stress effects are discussed. Reactions of designed joint to changes in temperature are described. Illustrations of conventional gimbal joint and improved gimbal joint are provided.

  5. 14 CFR 29.935 - Shafting joints.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...ROTORCRAFT Powerplant Rotor Drive System § 29.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation must have provision for...

  6. 14 CFR 29.935 - Shafting joints.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...ROTORCRAFT Powerplant Rotor Drive System § 29.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation must have provision for...

  7. 14 CFR 29.935 - Shafting joints.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...ROTORCRAFT Powerplant Rotor Drive System § 29.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation must have provision for...

  8. 14 CFR 27.935 - Shafting joints.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...ROTORCRAFT Powerplant Rotor Drive System § 27.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation must have provision for...

  9. 14 CFR 27.935 - Shafting joints.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...ROTORCRAFT Powerplant Rotor Drive System § 27.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation must have provision for...

  10. 14 CFR 29.935 - Shafting joints.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...ROTORCRAFT Powerplant Rotor Drive System § 29.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation must have provision for...

  11. 14 CFR 29.935 - Shafting joints.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...ROTORCRAFT Powerplant Rotor Drive System § 29.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation must have provision for...

  12. 14 CFR 27.935 - Shafting joints.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...ROTORCRAFT Powerplant Rotor Drive System § 27.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation must have provision for...

  13. 14 CFR 27.935 - Shafting joints.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...ROTORCRAFT Powerplant Rotor Drive System § 27.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation must have provision for...

  14. 14 CFR 27.935 - Shafting joints.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...ROTORCRAFT Powerplant Rotor Drive System § 27.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation must have provision for...

  15. Formation of tough composite joints

    SciTech Connect

    Brun, M.K. [GE Corporate Research and Development, Schenectady, NY (United States)

    1997-05-01

    Joints which exhibit tough fracture behavior were formed in a composite with a Si/SiC matrix reinforced with Textron SCS-6 fibers with either boron nitride or silicon nitride fiber coatings. In composites with BN coatings fibers were aligned uniaxially, while composites with Si{sub 3}N{sub 4}-coated fibers had a 0/90{degree} architecture. Lapped joints (joints with overlapping fingers) were necessary to obtain tough behavior. Geometrical requirements necessary to avoid brittle joint failure have been proposed. Joints with a simple overlap geometry (only a few fingers) would have to be very long in order to prevent brittle failure. Typical failure in these joints is caused by a crack propagating along the interfaces between the joint fingers. Joints of the same overall length, but with geometry changed to be symmetric about the joint centerline and with an extra shear surface exhibited tough fractures accompanied with extensive fiber pullout. The initial matrix cracking of these joints was relatively low because cracks propagated easily through the ends of the fingers. Joints with an optimized stepped sawtooth geometry produced composite-like failures with the stress/strain curves containing an elastic region followed by a region of rising stress with an increase of strain. Increasing the fiber/matrix interfacial strength from 9 to 25 MPa, by changing the fiber coating, increased matrix cracking and ultimate strength of the composite significantly. The best joints had matrix cracking stress and ultimate strength of 138 and 240 MPa, respectively. Joint failure was preceded by multiple matrix cracking in the entire composite. The high strength of the joints will permit building of structures containing joints with only a minor reduction of design stresses.

  16. Health & Demographic Surveillance System Profile: The Kombewa Health and Demographic Surveillance System (Kombewa HDSS).

    PubMed

    Sifuna, Peter; Oyugi, Mary; Ogutu, Bernhards; Andagalu, Ben; Otieno, Allan; Owira, Victorine; Otsyula, Nekoye; Oyieko, Janet; Cowden, Jessica; Otieno, Lucas; Otieno, Walter

    2014-08-01

    The Kombewa Health and Demographic Surveillance System (HDSS) grew out of the Kombewa Clinical Research Centre in 2007 and has since established itself as a platform for the conduct of regulated clinical trials, nested studies and local disease surveillance. The HDSS is located in a rural part of Kisumu County, Western Kenya, and covers an area of about 369 km(2) along the north-eastern shores of Lake Victoria. A dynamic cohort of 141 956 individuals drawn from 34 718 households forms the HDSS surveillance population. Following a baseline survey in 2011, the HDSS continues to monitor key population changes through routine biannual household surveys. The intervening period between set-up and baseline census was used for preparatory work, in particular Global Positioning System (GPS) mapping. Routine surveys capture information on individual and households including residency, household relationships, births, deaths, migrations (in and out) and causes of morbidity (syndromic incidence and prevalence) as well as causes of death (verbal autopsy). The Kombewa HDSS platform is used to support health research activities, that is clinical trials and epidemiological studies evaluating diseases of public health importance including malaria, HIV and global emerging infectious diseases such as dengue fever. PMID:25009309

  17. Child Pornography Possessors and Child Contact Sex Offenders: A Multilevel Comparison of Demographic Characteristics and Rates of Recidivism.

    PubMed

    Faust, Erik; Bickart, William; Renaud, Cheryl; Camp, Scott

    2014-02-19

    Considerable debate surrounds the topic of whether possessing or distributing online images of child pornography (CP) represents a new type of crime perpetrated by conventional sex offenders (e.g., child contact [CC] sex offenders), or whether individuals who commit these crimes differ from contact sex offenders in meaningful ways. The current study compares groups of Internet (CP) and CC sexual offenders, with each group's sexual offending history exclusively confined to its offense category. T tests were used to conduct bivariate comparisons of group demographics and criminal histories. Rates of recidivism were examined using survival curves and Cox proportional hazard regression models. Results showed significant differences on demographic and criminal history variables, with CP offenders demonstrating a lower frequency of prior criminal offending and substance abuse, and higher rates of pre-incarceration employment and level of education. Rates of recidivism were significantly different between the two groups, with CP offenders showing lower rates of re-offense for most measures of recidivism. When controlling for background characteristics and the timing of the event, CC offenders were at much greater risk for having an arrest for a new crime or a non-sexual violent crime than CP offenders. Treatment and policy implications are discussed, along with suggestions for future research. PMID:24556314

  18. A New Mechanism for Tracking Publicly Available Study Volunteer Demographics

    PubMed Central

    Zuckerman, Rachael; Getz, Kenneth; Kaitin, Kenneth

    2011-01-01

    The importance of gathering and monitoring aggregate demographic data on the annual population of study volunteers in FDA-regulated clinical trials is widely acknowledged. To date, no formal mechanism exists to capture this information. The Tufts Center for the Study of Drug Development identified and tested a publicly available source of information on clinical trial participant data, NDA Reviews stored in the FDA’s drugs@FDA database, to determine its accuracy, reliability, and feasibility. Thirty-seven new drug applications approved between 2006 and 2008 were evaluated and compared with published sources of demographic data. The authors conclude that the approach described here—NDA review extraction—provides reasonably reliable and conservative estimates of study volunteer demographics and can serve as a useful baseline until Clinicaltrials.gov or other, more complete, public sources become available. PMID:21625297

  19. [Demographic structure and dynamics of morbidity due to anthroponosis infections].

    PubMed

    Gerasimov, A N; Mindlina, A Ia; Polibin, R V; Briko, N I

    2010-01-01

    A fall in the incidence of both preventable and non-preventable or partly preventable infections with different modes of transmission has recently been documented in Russia and worldwide; it parallels marked changes in the demographic structure of the population. Simulation based on parasite-host mathematical models confirmed that demographic structure is a key factor responsible for the incidence of anthroponosis infections producing long-standing or lifelong immunity. It was shown that differences in the frequency of these diseases between countries may be due to different age structure of their populations. The lowered incidence of preventable and non-preventable infections in Russia appears to be associated with changes in the country's demographics. We have developed prognosis of further dynamics of anthroponosis diseases that predicts reversal of the mean morbidity rate toward that recorded in the 1980s and the shift of its higher values to senior age-groups. PMID:21309156

  20. Preliminary bolted-joint data

    NASA Technical Reports Server (NTRS)

    Wichorek, G. R.

    1979-01-01

    Bolted-joint strength and failure modes for advanced graphite/polyimide composite laminates at 116K (-250 F), room temperature, and 589K (600 F) were determined to provide preliminary design data. The bolted-joint test setup for the low and elevated temperature tests is described. Test results are reported on a quasi-isotropic laminate of Celion 6000/PMR-15. Single bolt, double lap shear specimens were tested to obtain maximum joint strength and failure mode. The effect of joint geometry and temperature on joint strength and failure mode is presented.

  1. Prosthetic elbow joint

    NASA Technical Reports Server (NTRS)

    Weddendorf, Bruce C. (inventor)

    1994-01-01

    An artificial, manually positionable elbow joint for use in an upper extremity, above-elbow, prosthetic is described. The prosthesis provides a locking feature that is easily controlled by the wearer. The instant elbow joint is very strong and durable enough to withstand the repeated heavy loadings encountered by a wearer who works in an industrial, construction, farming, or similar environment. The elbow joint of the present invention comprises a turntable, a frame, a forearm, and a locking assembly. The frame generally includes a housing for the locking assembly and two protruding ears. The forearm includes an elongated beam having a cup-shaped cylindrical member at one end and a locking wheel having a plurality of holes along a circular arc on its other end with a central bore for pivotal attachment to the protruding ears of the frame. The locking assembly includes a collar having a central opening with a plurality of internal grooves, a plurality of internal cam members each having a chamfered surface at one end and a V-shaped slot at its other end; an elongated locking pin having a crown wheel with cam surfaces and locking lugs secured thereto; two coiled compression springs; and a flexible filament attached to one end of the elongated locking pin and extending from the locking assembly for extending and retracting the locking pin into the holes in the locking wheel to permit selective adjustment of the forearm relative to the frame. In use, the turntable is affixed to the upper arm part of the prosthetic in the conventional manner, and the cup-shaped cylindrical member on one end of the forearm is affixed to the forearm piece of the prosthetic in the conventional manner. The elbow joint is easily adjusted and locked between maximum flex and extended positions.

  2. Formation of tough composite joints

    SciTech Connect

    Brun, M.K. [GE Corporate Research and Development, Schenectady, NY (United States)

    1998-12-01

    Joints that exhibited tough fracture behavior were formed in a Si/SiC matrix reinforced with Textron SCS-6 fibers with either boron nitride or silicon nitride fiber coatings. Lapped joints (joints with overlapping fingers) were necessary to obtain tough behavior. Geometrical requirements necessary to avoid brittle joint failure were proposed. Joints with a simple overlap geometry (only a few fingers) had to be very long in order to prevent brittle failure. Joints with an optimized stepped sawtooth geometry produced composite-like failures with the stress/strain curves containing an elastic region followed by a region of rising stress with an increase of strain. Increasing the fiber/matrix interfacial strength, by changing the fiber coating, significantly increased matrix cracking and ultimate strength of the joints. The best joints had matrix cracking stress and ultimate strength of 138 and 240 MPa, respectively. Joint failure was preceded by multiple matrix cracking in the entire composite. The high strength of the joints should permit building of structures containing joints with only a minor reduction of design stresses.

  3. Demographic Processes Underlying Subtle Patterns of Population Structure in the Scalloped Hammerhead Shark, Sphyrna lewini

    PubMed Central

    Nance, Holly A.; Klimley, Peter; Galván-Magańa, Felipe; Martínez-Ortíz, Jimmy; Marko, Peter B.

    2011-01-01

    Genetic diversity (?), effective population size (Ne), and contemporary levels of gene flow are important parameters to estimate for species of conservation concern, such as the globally endangered scalloped hammerhead shark, Sphyrna lewini. Therefore, we have reconstructed the demographic history of S. lewini across its Eastern Pacific (EP) range by applying classical and coalescent population genetic methods to a combination of 15 microsatellite loci and mtDNA control region sequences. In addition to significant population genetic structure and isolation-by-distance among seven coastal sites between central Mexico and Ecuador, the analyses revealed that all populations have experienced a bottleneck and that all current values of ? are at least an order of magnitude smaller than ancestral ?, indicating large decreases in Ne (??=?4Ne?), where ? is the mutation rate. Application of the isolation-with-migration (IM) model showed modest but significant genetic connectivity between most sampled sites (point estimates of Nm?=?0.1–16.7), with divergence times (t) among all populations significantly greater than zero. Using a conservative (i.e., slow) fossil-based taxon-specific phylogenetic calibration for mtDNA mutation rates, posterior probability distributions (PPDs) for the onset of the decline in Ne predate modern fishing in this region. The cause of decline over the last several thousand years is unknown but is highly atypical as a post-glacial demographic history. Regardless of the cause, our data and analyses suggest that S. lewini was far more abundant throughout the EP in the past than at present. PMID:21789171

  4. Demographic Outcomes and Ecosystem Implications of Giant Tortoise Reintroduction to Espańola Island, Galapagos

    PubMed Central

    Gibbs, James P.; Hunter, Elizabeth A.; Shoemaker, Kevin T.; Tapia, Washington H.; Cayot, Linda J.

    2014-01-01

    Restoration of extirpated species via captive breeding has typically relied on population viability as the primary criterion for evaluating success. This criterion is inadequate when species reintroduction is undertaken to restore ecological functions and interactions. Herein we report on the demographic and ecological outcomes of a five-decade-long population restoration program for a critically endangered species of “ecosystem engineer”: the endemic Espańola giant Galapagos tortoise (Chelonoidis hoodensis). Our analysis of complementary datasets on tortoise demography and movement, tortoise-plant interactions and Espańola Island’s vegetation history indicated that the repatriated tortoise population is secure from a strictly demographic perspective: about half of tortoises released on the island since 1975 were still alive in 2007, in situ reproduction is now significant, and future extinction risk is low with or without continued repatriation. Declining survival rates, somatic growth rates, and body condition of repatriates suggests, however, that resources for continued population growth are increasingly limited. Soil stable carbon isotope analyses indicated a pronounced shift toward woody plants in the recent history of the island’s plant community, likely a legacy of changes in competitive relations between woody and herbaceous plants induced by now-eradicated feral goats and prolonged absence of tortoises. Woody plants are of concern because they block tortoise movement and hinder recruitment of cactus–a critical resource for tortoises. Tortoises restrict themselves to remnant cactus patches and areas of low woody plant density in the center of the island despite an apparent capacity to colonize a far greater range, likely because of a lack of cactus elsewhere on the island. We conclude that ecosystem-level criteria for success of species reintroduction efforts take much longer to achieve than population-level criteria; moreover, reinstatement of endangered species as fully functioning ecosystem engineers may often require large-scale habitat restoration efforts in concert with population restoration. PMID:25350744

  5. Benign joint hypermobility syndrome in soldiers; what is the effect of military training courses on associated joint instabilities?

    PubMed Central

    Azma, Kamran; Mottaghi, Peyman; Hosseini, Alireza; Abadi, Hossein Hassan; Nouraei, Mohammad Hadi

    2014-01-01

    Background: Hypermobile joints are joints with beyond normal range of motion and may be associated with joint derangements. This study aimed to evaluate the prevalence of benign joint hypermobility syndrome (BJHS) among soldiers and effect of training courses on related joint instabilities. Materials and Methods: In a prospective cohort study on 721 soldiers of Iran Army in Isfahan in 2013 the prevalence of joint hypermobility was obtained by using Beighton criteria. Soldiers divided in two groups of healthy and suffered based on their scores. The prevalence of ankle sprain, shoulder and temporomandibular joint (TMJ) dislocations identified before beginning service by history-taking and reviewing paraclinical documents. After 3 months of military training, a recent occurrence of mentioned diseases was revaluated in two groups. The collected data were analyzed using SPSS-20 software using Independent-T and Chi-square tests. Results: The frequency of BJHS before military training was 29.4%. After passing military training period, the incidence of ankle sprain was significantly higher in suffered group achieving the minimum Beighton score (BS) of 4 (4.3%, P = 0.03), 5 (5.5%, P = 0.005) and also 6 out of 9 (6.5%, P = 0.01). The incidence of TMJ dislocation was not significantly different based on a minimum score of 4, while it was higher in suffered group when considering the score of 5 (2.1%) and 6 (2.6%) for discrimination of two groups (P = 0.03). There was no significant difference between two groups in case of shoulder dislocation anyway. Conclusion: Military training can increase the incidence of ankle sprains and TMJ dislocations in hypermobility persons with higher BS in comparison with healthy people. Therefore, screening of joint hypermobility may be useful in identifying individuals at increased risk for joint instabilities. PMID:25364364

  6. History of Geology.

    ERIC Educational Resources Information Center

    Greene, Mott T.

    1985-01-01

    Discusses: (1) geologists and the history of geology; (2) American historians and the history of geology; (3) history of geology in the 1980s; (4) sources for the history of geology (bibliographies, dictionaries, encyclopedias, handbooks, periodicals, public/official histories, compilations, and books); (5) research opportunities; and (6) other…

  7. Social and demographic principles in an alternative typology of cities.

    PubMed

    Kozlov, G S; Misnikov, Y G

    1990-02-01

    "The authors challenge some conventional notions regarding the USSR's urban hierarchy and settlement network and the basis for functional city classifications. They assign a key role to technological and social change in the overall growth and development process and downplay the role of territorial production complexes vis-a-vis large cities as major regulators of future economic development. Considerable attention is devoted to identifying stages of urban interaction (especially via migration and innovation diffusion) with the rural hinterland and of social-demographic transformations accompanying scientific and technical progress. A city typology based on stages in the 'social-demographic transition' is outlined briefly." PMID:12282737

  8. The demographic transition: an attempt to reformulate a population theory.

    PubMed

    Hofsten, E

    1981-01-01

    In this effort to reformulate the demographic transition theory, attention is directed to the following: Malthus and Karl Marx's criticism of his principle of population; the 1st stage of transition, i.e., high mortality, high fertility, and slow population growth; the 2nd stage of declining mortality; the 3rd stage of declining fertility; the 4th stage when mortality and fertility are both low; the growth potential; and the demographic transition in the 3rd world countries. The demographic transition theory has become popular among demographers, economists, historians, and others interested in studying the development of population over time since the end of World War 2. This interest has most likely been created by the anxiety over the population explosion in the 3rd world countries. Transition has made demographers believe that the period of rapid population growth will be automatically succeeded by a period of more or less constant population size. The question that arises is whether it is as simple as that. Demographic transition has to a great extent taken the place of Malthus' principle of population as a general theory of population. Demographic transition appears to describe in a satisfactory way the development of population which all currently industrialized countires have passed through, when going from the preindustrial to the present industrialized stage. The objectives to demographic transition as a general theory are considered. Some of the factors which have accounted for the decline in fertility in Europe may also apply to the 3rd world countries. 1 such factor is the effect of reduced infant and child mortality on the individual level. The fertility decline, caused by reduced infant and child mortality may, however, be of limited size. The great amount of unemployment in the 3rd world may affect fertility in a downward direction. The fertility decline in Europe occurred simultaneously with an industrialization process, which gradually covered the entire population. In most 3rd world countries the "modernization" that is going on implies that a small industrialized sector with its subsistence agriculture is left more or less untouched. There remains a strong incentive for many children in this kind of society. A rapid decline in fertility cannot be expected under these circumstances. To realize a thorough change in the social structure and in the social relations is necessary. PMID:12177839

  9. The history of AIDS exceptionalism

    PubMed Central

    2010-01-01

    In the history of public health, HIV/AIDS is unique; it has widespread and long-lasting demographic, social, economic and political impacts. The global response has been unprecedented. AIDS exceptionalism - the idea that the disease requires a response above and beyond "normal" health interventions - began as a Western response to the originally terrifying and lethal nature of the virus. More recently, AIDS exceptionalism came to refer to the disease-specific global response and the resources dedicated to addressing the epidemic. There has been a backlash against this exceptionalism, with critics claiming that HIV/AIDS receives a disproportionate amount of international aid and health funding. This paper situations this debate in historical perspective. By reviewing histories of the disease, policy developments and funding patterns, it charts how the meaning of AIDS exceptionalism has shifted over three decades. It argues that while the connotation of the term has changed, the epidemic has maintained its course, and therefore some of the justifications for exceptionalism remain. PMID:21129197

  10. The Automobile in American History History 392

    E-print Network

    Abolmaesumi, Purang

    " and women and history and sources #12;2 Also browse subject headings and look for these special subject terms. Women--United States--History--Sources Women--United States--Social conditions period: Advertising

  11. History Channel: This Day in History

    NSDL National Science Digital Library

    For those looking to find out about a variety of important historical events on a particular day, this site provided by the History Channel will be both entertaining and informative. This Day in History collects information about historical events organized around a number of topical sections, such as Cold War History, Literary History, Old West History, Technology History, Wall Street History, and Civil War History. Along with brief essays describing the events of a particular day, some of the more recent events also have short video clips that users can watch. On one recent day (January 28th), events covered included the tragic explosion of the Challenger space shuttle in 1986 and the United States' failure to capture Pancho Villa, the Mexican revolutionary. Visitors can also type in their birthdays to find out about events that occurred on that day, as well as for a list of well-known persons who share their birthday.

  12. The History of Sexuality History 464

    E-print Network

    Abolmaesumi, Purang

    1990 Encyclopedia of Lesbian, Gay, Bisexual, and Transgender History in America (online) Gay Histories documents or speeches in the title. (gay? or homosexual?) and speeches B. Look up Historical Figures

  13. Demographic, epidemiological, and health transitions: are they relevant to population health patterns in Africa?

    PubMed Central

    Kuate Defo, Barthélémy

    2014-01-01

    Background Studies of trends in population changes and epidemiological profiles in the developing world have overwhelmingly relied upon the concepts of demographic, epidemiological, and health transitions, even though their usefulness in describing and understanding population and health trends in developing countries has been repeatedly called into question. The issue is particularly relevant for the study of population health patterns in Africa and sub-Saharan Africa, as the history and experience there differs substantially from that of Western Europe and North America, for which these concepts were originally developed. Objective The aim of this study is two-fold: to review and clarify any distinction between the concepts of demographic transition, epidemiological transition and health transition and to identify summary indicators of population health to test how well these concepts apply in Africa. Results Notwithstanding the characteristically diverse African context, Africa is a continent of uncertainties and emergencies where discontinuities and interruptions of health, disease, and mortality trends reflect the enduring fragility and instability of countries and the vulnerabilities of individuals and populations in the continent. Africa as a whole remains the furthest behind the world's regions in terms of health improvements and longevity, as do its sub-Saharan African regions and societies specifically. This study documents: 1) theoretically and empirically the similarities and differences between the demographic transition, epidemiological transition, and health transition; 2) simple summary indicators that can be used to evaluate their descriptive and predictive features; 3) marked disparities in the onset and pace of variations and divergent trends in health, disease, and mortality patterns as well as fertility and life expectancy trajectories among African countries and regions over the past 60 years; 4) the rapid decline in infant mortality and gains in life expectancy from the 1950s through the 1990s in a context of preponderant communicable diseases in all African countries; 5) the salient role of adult mortality, mostly ascribed to HIV/AIDS and co-morbidities, since the 1990s in reversing trends in mortality decline, its interruption of life expectancy improvements, and its reversal of gender differences in life expectancies disadvantaging women in several countries with the highest prevalence of HIV/AIDS; 6) the huge impact of wars in reversing the trends in under-five mortality decline in sub-Saharan countries in the 1990s and beyond. These assessments of these transition frameworks and these phenomena were not well documented to date for all five regions and 57 countries of Africa. Conclusion Prevailing frameworks of demographic, epidemiological, and health transitions as descriptive and predictive models are incomplete or irrelevant for charting the population and health experiences and prospects of national populations in the African context. PMID:24848648

  14. Bone Health History in Breast Cancer Patients on Aromatase Inhibitors

    PubMed Central

    Kwan, Marilyn L.; Lo, Joan C.; Tang, Li; Laurent, Cecile A.; Roh, Janise M.; Chandra, Malini; Hahn, Theresa E.; Hong, Chi-Chen; Sucheston-Campbell, Lara; Hershman, Dawn L.; Quesenberry, Charles P.; Ambrosone, Christine B.; Kushi, Lawrence H.; Yao, Song

    2014-01-01

    A cross-sectional study was performed to assess bone health history among aromatase inhibitor (AI) users before breast cancer (BC) diagnosis, which may impact fracture risk after AI therapy and choice of initial hormonal therapy. A total of 2,157 invasive BC patients initially treated with an AI were identified from a prospective cohort study at Kaiser Permanente Northern California (KPNC). Data on demographic and lifestyle factors were obtained from in-person interviews, and bone health history and clinical data from KPNC clinical databases. The prevalence of osteoporosis and fractures in postmenopausal AI users was assessed, compared with 325 postmenopausal TAM users. The associations of bone health history with demographic and lifestyle factors in AI users were also examined. Among all initial AI users, 11.2% had a prior history of osteoporosis, 16.3% had a prior history of any fracture, and 4.6% had a prior history of major fracture. Postmenopausal women who were taking TAM as their initial hormonal therapy had significantly higher prevalence of prior osteoporosis than postmenopausal AI users (21.5% vs. 11.8%, p<0.0001). Among initial AI users, the associations of history of osteoporosis and fracture in BC patients with demographic and lifestyle factors were, in general, consistent with those known in healthy older women. This study is one of the first to characterize AI users and risk factors for bone morbidity before BC diagnosis. In the future, this study will examine lifestyle, molecular, and genetic risk factors for AI-induced fractures. PMID:25354083

  15. Hominin life history: reconstruction and evolution.

    PubMed

    Robson, Shannen L; Wood, Bernard

    2008-04-01

    In this review we attempt to reconstruct the evolutionary history of hominin life history from extant and fossil evidence. We utilize demographic life history theory and distinguish life history variables, traits such as weaning, age at sexual maturity, and life span, from life history-related variables such as body mass, brain growth, and dental development. The latter are either linked with, or can be used to make inferences about, life history, thus providing an opportunity for estimating life history parameters in fossil taxa. We compare the life history variables of modern great apes and identify traits that are likely to be shared by the last common ancestor of Pan-Homo and those likely to be derived in hominins. All great apes exhibit slow life histories and we infer this to be true of the last common ancestor of Pan-Homo and the stem hominin. Modern human life histories are even slower, exhibiting distinctively long post-menopausal life spans and later ages at maturity, pointing to a reduction in adult mortality since the Pan-Homo split. We suggest that lower adult mortality, distinctively short interbirth intervals, and early weaning characteristic of modern humans are derived features resulting from cooperative breeding. We evaluate the fidelity of three life history-related variables, body mass, brain growth and dental development, with the life history parameters of living great apes. We found that body mass is the best predictor of great ape life history events. Brain growth trajectories and dental development and eruption are weakly related proxies and inferences from them should be made with caution. We evaluate the evidence of life history-related variables available for extinct species and find that prior to the transitional hominins there is no evidence of any hominin taxon possessing a body size, brain size or aspects of dental development much different from what we assume to be the primitive life history pattern for the Pan-Homo clade. Data for life history-related variables among the transitional hominin grade are consistent and none agrees with a modern human pattern. Aside from mean body mass, adult brain size, crown and root formation times, and the timing and sequence of dental eruption of Homo erectus are inconsistent with that of modern humans. Homo antecessor fossil material suggests a brain size similar to that of Homo erectus s. s., and crown formation times that are not yet modern, though there is some evidence of modern human-like timing of tooth formation and eruption. The body sizes, brain sizes, and dental development of Homo heidelbergensis and Homo neanderthalensis are consistent with a modern human life history but samples are too small to be certain that they have life histories within the modern human range. As more life history-related variable information for hominin species accumulates we are discovering that they can also have distinctive life histories that do not conform to any living model. At least one extinct hominin subclade, Paranthropus, has a pattern of dental life history-related variables that most likely set it apart from the life histories of both modern humans and chimpanzees. PMID:18380863

  16. Hominin life history: reconstruction and evolution

    PubMed Central

    Robson, Shannen L; Wood, Bernard

    2008-01-01

    In this review we attempt to reconstruct the evolutionary history of hominin life history from extant and fossil evidence. We utilize demographic life history theory and distinguish life history variables, traits such as weaning, age at sexual maturity, and life span, from life history-related variables such as body mass, brain growth, and dental development. The latter are either linked with, or can be used to make inferences about, life history, thus providing an opportunity for estimating life history parameters in fossil taxa. We compare the life history variables of modern great apes and identify traits that are likely to be shared by the last common ancestor of Pan-Homo and those likely to be derived in hominins. All great apes exhibit slow life histories and we infer this to be true of the last common ancestor of Pan-Homo and the stem hominin. Modern human life histories are even slower, exhibiting distinctively long post-menopausal life spans and later ages at maturity, pointing to a reduction in adult mortality since the Pan-Homo split. We suggest that lower adult mortality, distinctively short interbirth intervals, and early weaning characteristic of modern humans are derived features resulting from cooperative breeding. We evaluate the fidelity of three life history-related variables, body mass, brain growth and dental development, with the life history parameters of living great apes. We found that body mass is the best predictor of great ape life history events. Brain growth trajectories and dental development and eruption are weakly related proxies and inferences from them should be made with caution. We evaluate the evidence of life history-related variables available for extinct species and find that prior to the transitional hominins there is no evidence of any hominin taxon possessing a body size, brain size or aspects of dental development much different from what we assume to be the primitive life history pattern for the Pan-Homo clade. Data for life history-related variables among the transitional hominin grade are consistent and none agrees with a modern human pattern. Aside from mean body mass, adult brain size, crown and root formation times, and the timing and sequence of dental eruption of Homo erectus are inconsistent with that of modern humans. Homo antecessor fossil material suggests a brain size similar to that of Homo erectus s. s., and crown formation times that are not yet modern, though there is some evidence of modern human-like timing of tooth formation and eruption. The body sizes, brain sizes, and dental development of Homo heidelbergensis and Homo neanderthalensis are consistent with a modern human life history but samples are too small to be certain that they have life histories within the modern human range. As more life history-related variable information for hominin species accumulates we are discovering that they can also have distinctive life histories that do not conform to any living model. At least one extinct hominin subclade, Paranthropus, has a pattern of dental life history-related variables that most likely set it apart from the life histories of both modern humans and chimpanzees. PMID:18380863

  17. Progressive Damage Modeling of Durable Bonded Joint Technology

    NASA Technical Reports Server (NTRS)

    Leone, Frank A.; Davila, Carlos G.; Lin, Shih-Yung; Smeltzer, Stan; Girolamo, Donato; Ghose, Sayata; Guzman, Juan C.; McCarville, Duglas A.

    2013-01-01

    The development of durable bonded joint technology for assembling composite structures for launch vehicles is being pursued for the U.S. Space Launch System. The present work is related to the development and application of progressive damage modeling techniques to bonded joint technology applicable to a wide range of sandwich structures for a Heavy Lift Launch Vehicle. The joint designs studied in this work include a conventional composite splice joint and a NASA-patented Durable Redundant Joint. Both designs involve a honeycomb sandwich with carbon/epoxy facesheets joined with adhesively bonded doublers. Progressive damage modeling allows for the prediction of the initiation and evolution of damage. For structures that include multiple materials, the number of potential failure mechanisms that must be considered increases the complexity of the analyses. Potential failure mechanisms include fiber fracture, matrix cracking, delamination, core crushing, adhesive failure, and their interactions. The joints were modeled using Abaqus parametric finite element models, in which damage was modeled with user-written subroutines. Each ply was meshed discretely, and layers of cohesive elements were used to account for delaminations and to model the adhesive layers. Good correlation with experimental results was achieved both in terms of load-displacement history and predicted failure mechanisms.

  18. History of Silk

    NSDL National Science Digital Library

    0000-00-00

    Nicely illustrated history of silk and explanation of silk production. A fine discussion of the moths, life history, and feeding are included, as well as the extensive cultural history of this outstanding insect product.

  19. Department of History Conference

    E-print Network

    van den Berg, Jur

    Department of History Conference 2013 PRACTICING HISTORY #12; CTIHB RoomDannell Obsessed by History: Mormons and the Heritage Industry Sam DeMonja From on the Epidemiological Frontier of Portuguese America Daniel Shackelford The First Servant

  20. What history courses are there? History and Film Studies

    E-print Network

    Sussex, University of

    Essentials What history courses are there? History History and Film Studies History and Philosophy History and Politics History and Sociology American Studies and History (p33) Anthropology and History (p35) English and History (p69) What A levels/IB scores do I need? (For other qualifications