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Sample records for adult population size

  1. Spatiotemporal relationship between adult census size and genetic population size across a wide population size gradient.

    PubMed

    Bernos, Thaїs A; Fraser, Dylan J

    2016-09-01

    Adult census population size (N) and effective number of breeders (Nb ) are highly relevant for designing effective conservation strategies. Both parameters are often challenging to quantify, however, making it of interest to determine whether one parameter can be generalized from the other. Yet, the spatiotemporal relationship between N and Nb has not been well characterized empirically in many taxa. We analysed this relationship for 5-7 consecutive years in twelve brook trout populations varying greatly in N (49-10032) and Nb (3-567) and identified major environmental variables affecting the two parameters. N or habitat size alone explained 47-57% of the variance in Nb , and Nb was strongly correlated with effective population size. The ratio Nb /N ranged from 0.01 to 0.45 and increased at small N or following an annual decrease in N, suggesting density-dependent constraints on Nb . We found no evidence for a consistent, directional difference between variability in Nb and/or Nb /N among small and large populations; however, small populations had more varying temporal variability in Nb /N ratios than large populations. Finally, Nb and Nb /N were 2.5- and 2.3-fold more variable among populations than temporally within populations. Our results demonstrate a clear linkage between demographic and evolutionary parameters, suggesting that Nb could be used to approximate N (or vice versa) in natural populations. Nevertheless, using one variable to infer the other to monitor trends within populations is less recommended, perhaps even less so in small populations given their less predictable Nb vs. N dynamics. PMID:27483203

  2. Novel estimates of Aedes aegypti (Diptera: Culicidae) population size and adult survival based on Wolbachia releases.

    PubMed

    Ritchie, Scott A; Montgomery, Brian L; Hoffmann, Ary A

    2013-05-01

    The size of Aedes aegypti (L.) mosquito populations and adult survival rates have proven difficult to estimate because of a lack of consistent quantitative measures to equate sampling methods, such as adult trapping, to actual population size. However, such estimates are critical for devising control methods and for modeling the transmission of dengue and other infectious agents carried by this species. Here we take advantage of recent releases of Wolbachia-infected Ae. aegypti coupled with the results of ongoing monitoring to estimate the size of adult Ae. aegypti populations around Cairns in far north Queensland, Australia. Based on the association between released adults infected with Wolbachia and data from Biogents Sentinel traps, we show that data from two locations are consistent with population estimates of approximately 5-10 females per house and daily survival rates of 0.7-0.9 for the released Wolbachia-infected females. Moreover, we estimate that networks of Biogents Sentinel traps at a density of one per 15 houses capture around 5-10% of the adult population per week, and provide a rapid estimate of the absolute population size of Ae. aegypti. These data are discussed with respect to release rates and monitoring in future Wolbachia releases and also the levels of suppression required to reduce dengue transmission. PMID:23802459

  3. Estimating total population size for adult female sea turtles: Accounting for non-nesters

    USGS Publications Warehouse

    Kendall, W.L.; Richardson, J.I.; Rees, Alan F.

    2008-01-01

    Assessment of population size and changes therein is important to sea turtle management and population or life history research. Investigators might be interested in testing hypotheses about the effect of current population size or density (number of animals per unit resource) on future population processes. Decision makers might want to determine a level of allowable take of individual turtles of specified life stage. Nevertheless, monitoring most stages of sea turtle life histories is difficult, because obtaining access to individuals is difficult. Although in-water assessments are becoming more common, nesting females and their hatchlings remain the most accessible life stages. In some cases adult females of a given nesting population are sufficiently philopatric that the population itself can be well defined. If a well designed tagging study is conducted on this population, survival, breeding probability, and the size of the nesting population in a given year can be estimated. However, with published statistical methodology the size of the entire breeding population (including those females skipping nesting in that year) cannot be estimated without assuming that each adult female in this population has the same probability of nesting in a given year (even those that had just nested in the previous year). We present a method for estimating the total size of a breeding population (including nesters those skipping nesting) from a tagging study limited to the nesting population, allowing for the probability of nesting in a given year to depend on an individual's nesting status in the previous year (i.e., a Markov process). From this we further develop estimators for rate of growth from year to year in both nesting population and total breeding population, and the proportion of the breeding population that is breeding in a given year. We also discuss assumptions and apply these methods to a breeding population of hawksbill sea turtles (Eretmochelys imbricata) from

  4. Adult Body Size, Hormone Receptor Status, and Premenopausal Breast Cancer Risk in a Multiethnic Population

    PubMed Central

    John, Esther M.; Sangaramoorthy, Meera; Phipps, Amanda I.; Koo, Jocelyn; Horn-Ross, Pamela L.

    2011-01-01

    Large body size has been associated with a reduced risk of premenopausal breast cancer in non-Hispanic white women. Data on other racial/ethnic populations are limited. The authors examined the association between premenopausal breast cancer risk and adult body size in 672 cases and 808 controls aged ≥35 years from a population-based case-control study conducted in 1995–2004 in the San Francisco Bay Area (Hispanics: 375 cases, 483 controls; African Americans: 154 cases, 160 controls; non-Hispanic whites: 143 cases, 165 controls). Multivariate adjusted odds ratios and 95% confidence intervals were calculated using unconditional logistic regression. Height was associated with increased breast cancer risk (highest vs. lowest quartile: odds ratio = 1.77, 95% confidence interval: 1.23, 2.53; Ptrend < 0.01); the association did not vary by hormone receptor status or race/ethnicity. Body mass index (measured as weight (kg) divided by height (m) squared) was inversely associated with risk in all 3 racial/ethnic groups, but only for estrogen receptor– and progesterone receptor–positive tumors (body mass index ≥30 vs. <25: odds ratio = 0.42; 95% confidence interval: 0.29, 0.61). Other body size measures (current weight, body build, adult weight gain, young adult weight and body mass index, waist circumference, and waist-to-height ratio) were similarly inversely associated with risk of estrogen receptor– and progesterone receptor–positive breast cancer but not estrogen receptor– and progesterone receptor–negative disease. Despite racial/ethnic differences in body size, inverse associations were similar across the 3 racial/ethnic groups when stratified by hormone receptor status. PMID:21084558

  5. Deformable adult human phantoms for radiation protection dosimetry: anthropometric data representing size distributions of adult worker populations and software algorithms

    NASA Astrophysics Data System (ADS)

    Hum Na, Yong; Zhang, Binquan; Zhang, Juying; Caracappa, Peter F.; Xu, X. George

    2010-07-01

    Computational phantoms representing workers and patients are essential in estimating organ doses from various occupational radiation exposures and medical procedures. Nearly all existing phantoms, however, were purposely designed to match internal and external anatomical features of the Reference Man as defined by the International Commission on Radiological Protection (ICRP). To reduce uncertainty in dose calculations caused by anatomical variations, a new generation of phantoms of varying organ and body sizes is needed. This paper presents detailed anatomical data in tables and graphs that are used to design such size-adjustable phantoms representing a range of adult individuals in terms of the body height, body weight and internal organ volume/mass. Two different sets of information are used to derive the phantom sets: (1) individual internal organ size and volume/mass distribution data derived from the recommendations of the ICRP in Publications 23 and 89 and (2) whole-body height and weight percentile data from the National Health and Nutrition Examination Survey (NHANES 1999-2002). The NHANES height and weight data for 19 year old males and females are used to estimate the distributions of individuals' size, which is unknown, that corresponds to the ICRP organ and tissue distributions. This paper then demonstrates the usage of these anthropometric data in the development of deformable anatomical phantoms. A pair of phantoms—modeled entirely in mesh surfaces—of the adult male and female, RPI-adult male (AM) and RPI-adult female (AF) are used as the base for size-adjustable phantoms. To create percentile-specific phantoms from these two base phantoms, organ surface boundaries are carefully altered according to the tabulated anthropometric data. Software algorithms are developed to automatically match the organ volumes and masses with desired values. Finally, these mesh-based, percentile-specific phantoms are converted into voxel-based phantoms for Monte

  6. Deformable adult human phantoms for radiation protection dosimetry: anthropometric data representing size distributions of adult worker populations and software algorithms.

    PubMed

    Na, Yong Hum; Zhang, Binquan; Zhang, Juying; Caracappa, Peter F; Xu, X George

    2010-07-01

    Computational phantoms representing workers and patients are essential in estimating organ doses from various occupational radiation exposures and medical procedures. Nearly all existing phantoms, however, were purposely designed to match internal and external anatomical features of the Reference Man as defined by the International Commission on Radiological Protection (ICRP). To reduce uncertainty in dose calculations caused by anatomical variations, a new generation of phantoms of varying organ and body sizes is needed. This paper presents detailed anatomical data in tables and graphs that are used to design such size-adjustable phantoms representing a range of adult individuals in terms of the body height, body weight and internal organ volume/mass. Two different sets of information are used to derive the phantom sets: (1) individual internal organ size and volume/mass distribution data derived from the recommendations of the ICRP in Publications 23 and 89 and (2) whole-body height and weight percentile data from the National Health and Nutrition Examination Survey (NHANES 1999-2002). The NHANES height and weight data for 19 year old males and females are used to estimate the distributions of individuals' size, which is unknown, that corresponds to the ICRP organ and tissue distributions. This paper then demonstrates the usage of these anthropometric data in the development of deformable anatomical phantoms. A pair of phantoms--modeled entirely in mesh surfaces--of the adult male and female, RPI-adult male (AM) and RPI-adult female (AF) are used as the base for size-adjustable phantoms. To create percentile-specific phantoms from these two base phantoms, organ surface boundaries are carefully altered according to the tabulated anthropometric data. Software algorithms are developed to automatically match the organ volumes and masses with desired values. Finally, these mesh-based, percentile-specific phantoms are converted into voxel-based phantoms for Monte Carlo

  7. [Assessment of the food list and serving size of a Food Frequency Questionnaire in an adult population].

    PubMed

    Tomita, Luciana Yuki; Cardoso, Marly Augusto

    2002-01-01

    This study examined both the food list and portion size values from a Food Frequency Questionnaire (FFQ) among participants in a case-control study in São Paulo, Brazil. Two hundred adult respondents to a case-control study were randomly selected (101 men and 99 women; age range: 35-69 years). FFQ food items were examined on the basis of their contribution to total population nutrient intake estimated by 24-hour dietary recall (1-DR). We examined the frequency distribution of equivalent-gram weights of each selected food from the 1-DR and identified the portion sizes as small, medium, and large in the distribution (percentiles 25, 50, and 75, respectively). The FFQ provided close estimation of total fat, saturated fatty acids, cholesterol, total fiber, vitamin B6, and folic acid compared to the 1-DR (paired t-test; p < 0.05). The FFQ food list covered the study population's main dietary nutrient sources.

  8. Life-history traits and effective population size in species with overlapping generations revisited: the importance of adult mortality.

    PubMed

    Waples, R S

    2016-10-01

    The relationship between life-history traits and the key eco-evolutionary parameters effective population size (Ne) and Ne/N is revisited for iteroparous species with overlapping generations, with a focus on the annual rate of adult mortality (d). Analytical methods based on populations with arbitrarily long adult lifespans are used to evaluate the influence of d on Ne, Ne/N and the factors that determine these parameters: adult abundance (N), generation length (T), age at maturity (α), the ratio of variance to mean reproductive success in one season by individuals of the same age (φ) and lifetime variance in reproductive success of individuals in a cohort (Vk•). Although the resulting estimators of N, T and Vk• are upwardly biased for species with short adult lifespans, the estimate of Ne/N is largely unbiased because biases in T are compensated for by biases in Vk• and N. For the first time, the contrasting effects of T and Vk• on Ne and Ne/N are jointly considered with respect to d and φ. A simple function of d and α based on the assumption of constant vital rates is shown to be a robust predictor (R(2)=0.78) of Ne/N in an empirical data set of life tables for 63 animal and plant species with diverse life histories. Results presented here should provide important context for interpreting the surge of genetically based estimates of Ne that has been fueled by the genomics revolution. PMID:27273324

  9. An estimate of the historic population size of adult pallid sturgeon in the upper Missouri river basin, Montana and North Dakota

    USGS Publications Warehouse

    Braaten, P.J.; Fuller, D.B.; Lott, R.D.; Jordan, G.R.

    2009-01-01

    Juvenile pallid sturgeon Scaphirhynchus albus raised in hatcheries and stocked in the wild are used to augment critically imperiled populations of this federally endangered species in the United States. For pallid sturgeon in recovery priority management area 2 (RPMA 2) of the Missouri River and lower Yellowstone River where natural recruitment has not occurred for decades, restoration programs aim to stock an annual minimum of 9000 juvenile pallid sturgeon for 20 years to re-establish a minimum population of 1700 adults. However, establishment of this target was based on general guidelines for maintaining the genetic integrity of populations rather than pallid sturgeon-specific demographic information because data on the historical population size was lacking. In this study, information from a recent population estimate (158 wild adults in 2004, 95% confidence interval 129-193 adults) and an empirically derived adult mortality rate (5%) was used in a cohort population model to back-estimate the historic abundance of adult pallid sturgeon in RPMA 2. Three back-estimation age models were developed, and assumed that adults alive during 2004 were 30-, 40-, or 50-years old. Based on these age assumptions, population sizes [??95% confidence intervals; (CI)] were back-estimated to 1989, 1979, and 1969 to approximate size of the population when individuals would have been sexually mature (15 years old) and capable of spawning. Back-estimations yielded predictions of 344 adults in 1989 (95% CI 281-420), 577 adults in 1979 (95% CI 471-704), and 968 adults in 1969 (95% CI 790-1182) for the 30-, 40-, and 50-year age models, respectively. Although several assumptions are inherent in the back-estimation models, results suggest the juvenile stocking program for pallid sturgeon will likely re-establish an adult population that equals in the short-term and exceeds in the long-term the predicted population numbers that occurred during past decades in RPMA 2. However, re

  10. Estimation of Aedes aegypti (Diptera: Culicidae) population size and adult male survival in an urban area in Panama

    PubMed Central

    Neira, Marco; Lacroix, Renaud; Cáceres, Lorenzo; Kaiser, Paul E; Young, Josue; Pineda, Lleysa; Black, Isaac; Sosa, Nestor; Nimmo, Derric; Alphey, Luke; McKemey, Andrew

    2014-01-01

    Traditional mosquito control strategies rely heavily on the use of chemical insecticides. However, concerns about the efficiency of traditional control methods, environmental impact and emerging pesticide resistance have highlighted the necessity for developing innovative tools for mosquito control. Some novel strategies, including release of insects carrying a dominant lethal gene (RIDL®), rely on the sustained release of modified male mosquitoes and therefore benefit from a thorough understanding of the biology of the male of the species. In this report we present the results of a mark-release-recapture study aimed at: (i) establishing the survival in the field of laboratory-reared, wild-type male Aedes aegypti and (b) estimating the size of the local adult Ae. aegypti population. The study took place in Panama, a country where recent increases in the incidence and severity of dengue cases have prompted health authorities to evaluate alternative strategies for vector control. Results suggest a life expectancy of 2.3 days for released male mosquitoes (confidence interval: 1.78-2.86). Overall, the male mosquito population was estimated at 58 males/ha (range 12-81 males/ha), which can be extrapolated to an average of 0.64 pupae/person for the study area. The practical implications of these results are discussed. PMID:25410991

  11. Population size and relative abundance of adult Alabama shad reaching jim woodruff lock and dam, Apalachicola River, Florida

    USGS Publications Warehouse

    Ely, Patrick C.; Young, S.P.; Isely, J.J.

    2008-01-01

    We estimated the population size of migrating Alabama shad Alosa alabamae below Jim Woodruff Lock and Dam in the Apalachicola River (located in the central panhandle of northwestern Florida) using mark-recapture and relative abundance techniques. After adjustment for tag loss, emigration, and mortality, the population size was estimated as 25,935 (95% confidence interval, 17,715-39,535) in 2005, 2,767 (838-5,031) in 2006, and 8,511 (5,211-14,674) in 2007. The cumulative catch rate from boat electrofishing averaged 20.47 Alabama shad per hour in 2005, 6.10 per hour in 2006, and 13.17 per hour in 2007. The relationship between population size (N) and electrofishing catch per unit effort (CPUE) was modeled by the equation N = -9008.2 + (electrofishing CPUE X 1616.4). Additionally, in 2007 the hook-and-line catch rate averaged 1.94 Alabama shad per rod hour. A predictive model relating the population size and hook-and-line CPUE of spawning American shad A. sapidissima was applied to Alabama shad hook-and-line CPUE and produced satisfactory results. Recent spawning populations of Alabama shad in the Apalachicola River are low relative to American shad populations in other southeastern U.S. rivers. ?? Copyright by the American Fisheries Society 2008.

  12. Effective sizes for subdivided populations

    SciTech Connect

    Chesser, R.K. Univ. of Georgia, Athens, GA ); Rhodes, O.E. Jr.; Sugg, D.W.; Schnabel, A. )

    1993-12-01

    Many derivations of effective population sizes have been suggested in the literature; however, few account for the breeding structure and none can readily be expanded to subdivided populations. Breeding structures influence gene correlations through their effects on the number of breeding individuals of each sex, the mean number of progeny per female, and the variance in the number of progeny produced by males and females. Additionally, hierarchical structuring in a population is determined by the number of breeding groups and the migration rates of males and females among such groups. This study derives analytical solutions for effective sizes that can be applied to subdivided populations. Parameters that encapsulate breeding structure and subdivision are utilized to derive the traditional inbreeding and variance effective sizes. Also, it is shown that effective sizes can be determined for any hierarchical level of population structure for which gene correlations can accrue. Derivations of effective sizes for the accumulation of gene correlations within breeding groups (coancestral effective size) and among breeding groups (intergroup effective size) are given. The results converge to traditional single population measures when similar assumptions are applied. In particular, inbreeding and intergroup effective sizes are shown to be special cases of the coancestral effective size, and intergroup and variance effective sizes will be equal if the population census remains constant. Instantaneous solutions for effective size, at any time after gene correlation begins to accrue, are given in terms of traditional F statistics or transition equations. All effective sizes are shown to converge upon a common asymptotic value when breeding tactics and migration rates are constant. The asymptotic effective size can be expressed in terms of the fixation indices and the number of breeding groups; however, the rate of approach to the asymptote is dependent upon dispersal rates.

  13. Eating habits of a population undergoing a rapid dietary transition: portion sizes of traditional and non-traditional foods and beverages consumed by Inuit adults in Nunavut, Canada

    PubMed Central

    2013-01-01

    Background To determine the portion sizes of traditional and non-traditional foods being consumed by Inuit adults in three remote communities in Nunavut, Canada. Methods A cross-sectional study was carried out between June and October, 2008. Trained field workers collected dietary data using a culturally appropriate, validated quantitative food frequency questionnaire (QFFQ) developed specifically for the study population. Results Caribou, muktuk (whale blubber and skin) and Arctic char (salmon family), were the most commonly consumed traditional foods; mean portion sizes for traditional foods ranged from 10 g for fermented seal fat to 424 g for fried caribou. Fried bannock and white bread were consumed by >85% of participants; mean portion sizes for these foods were 189 g and 70 g, respectively. Sugar-sweetened beverages and energy-dense, nutrient-poor foods were also widely consumed. Mean portion sizes for regular pop and sweetened juices with added sugar were 663 g and 572 g, respectively. Mean portion sizes for potato chips, pilot biscuits, cakes, chocolate and cookies were 59 g, 59 g, 106 g, 59 g, and 46 g, respectively. Conclusions The present study provides further evidence of the nutrition transition that is occurring among Inuit in the Canadian Arctic. It also highlights a number of foods and beverages that could be targeted in future nutritional intervention programs aimed at obesity and diet-related chronic disease prevention in these and other Inuit communities. PMID:23724920

  14. Effective population size and population subdivision in demographically structured populations.

    PubMed Central

    Laporte, Valérie; Charlesworth, Brian

    2002-01-01

    A fast-timescale approximation is applied to the coalescent process in a single population, which is demographically structured by sex and/or age. This provides a general expression for the probability that a pair of alleles sampled from the population coalesce in the previous time interval. The effective population size is defined as the reciprocal of twice the product of generation time and the coalescence probability. Biologically explicit formulas for effective population size with discrete generations and separate sexes are derived for a variety of different modes of inheritance. The method is also applied to a nuclear gene in a population of partially self-fertilizing hermaphrodites. The effects of population subdivision on a demographically structured population are analyzed, using a matrix of net rates of movement of genes between different local populations. This involves weighting the migration probabilities of individuals of a given age/sex class by the contribution of this class to the leading left eigenvector of the matrix describing the movements of genes between age/sex classes. The effects of sex-specific migration and nonrandom distributions of offspring number on levels of genetic variability and among-population differentiation are described for different modes of inheritance in an island model. Data on DNA sequence variability in human and plant populations are discussed in the light of the results. PMID:12242257

  15. Population size, distribution and growth in Iran.

    PubMed

    Kamiar, M

    1985-01-01

    The author examines population size, distribution, and growth in Iran using data for 1966, 1976 census data, and some historical data for the nineteenth century. "This paper discusses changes in the size of population through time, population distribution, and regional patterns of population growth of the 23 provinces. It has been argued in this paper that because of a large family size norm as a religious duty to increase the numbers of the Islamic faith, early age at marriage, especially among females, common practice of polygamy, and the war with Iraq, population will grow even faster. It is concluded that population policy must be integrated into the national development plans."

  16. Population size and genome size in fishes: a closer look.

    PubMed

    Gregory, T Ryan; Witt, Jonathan D S

    2008-04-01

    The several thousand-fold range in genome size among animals has remained a subject of active research and debate for more than half a century, but no satisfactory explanation has yet been provided. Many one-dimensional models have been postulated, but so far none has been successful in accounting for observed patterns in genome size diversity. The recent model based on differences in effective population size appeared to gain empirical support with a study of genome size and inferred effective population size in fishes, but there were several questionable aspects of the analysis. First, it was based on an assumption that microsatellite heterozygosity indicates long-term effective population size, whereas in actuality these markers evolve quickly and are sensitive to demographic events. Second, it included both ancient polyploids and non-polyploids, the former of which did not gain their current genome sizes through the accumulation of slightly deleterious mutations as required in the model. Third, the analysis neglected the tremendous influence that Pleistocene glaciation bottlenecks had on heterozygosities in freshwater (and far less so, marine) fishes. In sum, it is apparent that genomes reached their current sizes in most fishes long before contemporary microsatellite heterozygosities were shaped, and that ancient polyploidy rather than the accumulation of mildly deleterious transposon insertions in small populations is the dominant factor that has influenced the large end of the range of genome sizes among fishes.

  17. Effective Population Sizes with Multiple Paternity

    PubMed Central

    Sugg, D. W.; Chesser, R. K.

    1994-01-01

    While the concept of effective population size is of obvious applicability to many questions in population genetics and conservation biology, its utility has suffered due to a lack of agreement among its various formulations. Often, mathematical formulations for effective sizes apply restrictive assumptions that limit their applicability. Herein, expressions for effective sizes of populations that account for mating tactics, biases in sex ratios, and differential dispersal rates (among other parameters) are developed. Of primary interest is the influence of multiple paternity on the maintenance of genetic variation in a population. In addition to the standard inbreeding and variance effective sizes, intragroup (coancestral) and intergroup effective sizes also are developed. Expressions for effective sizes are developed for the beginning of nonrandom gene exchanges (initial effective sizes), the transition of gene correlations (instantaneous effective sizes), and the steady-state (asymptotic effective size). Results indicate that systems of mating that incorporate more than one male mate per female increase all effective sizes above those expected from polygyny and monogamy. Instantaneous and asymptotic sizes can be expressed relative to the fixation indices. The parameters presented herein can be utilized in models of effective sizes for the study of evolutionary biology and conservation genetics. PMID:7982568

  18. Determining the Population Size of Pond Phytoplankton.

    ERIC Educational Resources Information Center

    Hummer, Paul J.

    1980-01-01

    Discusses methods for determining the population size of pond phytoplankton, including water sampling techniques, laboratory analysis of samples, and additional studies worthy of investigation in class or as individual projects. (CS)

  19. Annual recapture and survival rates of two non-breeding adult populations of Roseate Terns Stema dougallii captured on the Great Barrier Reef, Australia, and estimates of their population sizes

    USGS Publications Warehouse

    O'Neill, P.; Minton, C.D.T.; Nisbet, I.C.T.; Hines, J.E.

    2008-01-01

    Capture-recapture data from two disparate breeding populations of Roseate Terns (Sterna dougallii) captured together as non-breeding individuals from 2002 to 2007 in the southern Great Barrier Reef. Australia were analyzed for both survival rate and recapture rate. The average annual survival rate for the birds from the Asian population (S. d. bangsi) (0.901) is higher than that of the other population of unknown breeding origin (0.819). There was large variability in survival in both populations among years, but the average survival rate of 0.85 is similar to estimates for the same species in North America. The Cormack-Jolly-Seber models used in program MARK to estimate survival rates also produced estimated of recapture probabilities and population sizes. These estimates of population size were 29,000 for S. D. bangsi and 8,300 for the study area and much larger than the documented numbers in the likely breeding areas, suggesting that many breeding sites are currently unknown.

  20. Detecting past changes of effective population size.

    PubMed

    Nikolic, Natacha; Chevalet, Claude

    2014-06-01

    Understanding and predicting population abundance is a major challenge confronting scientists. Several genetic models have been developed using microsatellite markers to estimate the present and ancestral effective population sizes. However, to get an overview on the evolution of population requires that past fluctuation of population size be traceable. To address the question, we developed a new model estimating the past changes of effective population size from microsatellite by resolving coalescence theory and using approximate likelihoods in a Monte Carlo Markov Chain approach. The efficiency of the model and its sensitivity to gene flow and to assumptions on the mutational process were checked using simulated data and analysis. The model was found especially useful to provide evidence of transient changes of population size in the past. The times at which some past demographic events cannot be detected because they are too ancient and the risk that gene flow may suggest the false detection of a bottleneck are discussed considering the distribution of coalescence times. The method was applied on real data sets from several Atlantic salmon populations. The method called VarEff (Variation of Effective size) was implemented in the R package VarEff and is made available at https://qgsp.jouy.inra.fr and at http://cran.r-project.org/web/packages/VarEff.

  1. Prediction and estimation of effective population size.

    PubMed

    Wang, J; Santiago, E; Caballero, A

    2016-10-01

    Effective population size (Ne) is a key parameter in population genetics. It has important applications in evolutionary biology, conservation genetics and plant and animal breeding, because it measures the rates of genetic drift and inbreeding and affects the efficacy of systematic evolutionary forces, such as mutation, selection and migration. We review the developments in predictive equations and estimation methodologies of effective size. In the prediction part, we focus on the equations for populations with different modes of reproduction, for populations under selection for unlinked or linked loci and for the specific applications to conservation genetics. In the estimation part, we focus on methods developed for estimating the current or recent effective size from molecular marker or sequence data. We discuss some underdeveloped areas in predicting and estimating Ne for future research. PMID:27353047

  2. Prediction and estimation of effective population size.

    PubMed

    Wang, J; Santiago, E; Caballero, A

    2016-10-01

    Effective population size (Ne) is a key parameter in population genetics. It has important applications in evolutionary biology, conservation genetics and plant and animal breeding, because it measures the rates of genetic drift and inbreeding and affects the efficacy of systematic evolutionary forces, such as mutation, selection and migration. We review the developments in predictive equations and estimation methodologies of effective size. In the prediction part, we focus on the equations for populations with different modes of reproduction, for populations under selection for unlinked or linked loci and for the specific applications to conservation genetics. In the estimation part, we focus on methods developed for estimating the current or recent effective size from molecular marker or sequence data. We discuss some underdeveloped areas in predicting and estimating Ne for future research.

  3. Assessing minimum viable population size: Demography meets population genetics.

    PubMed

    Nunney, L; Campbell, K A

    1993-07-01

    The discussion of a population's minimum viable size provides a focus for the study of ecological and genetic factors that influence the persistence of a threatened population. There are many causes of extinction and the fate of a specific population cannot generally be predicted. This uncertainty has been dealt with in two ways: through stochastic demographic models to determine how to minimize extinction probabilities; and through population genetic theory to determine how best to maintain genetic variation, in the belief that the ability to evolve helps buffer a population against the unknown. Recent work suggests that these two very different approaches lead to very similar conclusions, at least under panmictic conditions. However, defining the ideal spatial distribution for an endangered species remains an important challenge.

  4. Family size and effective population size in a hatchery stock of coho salmon (Oncorhynchus kisutch)

    USGS Publications Warehouse

    Simon, R.C.; McIntyre, J.D.; Hemmingsen, A.R.

    1986-01-01

    Means and variances of family size measured in five year-classes of wire-tagged coho salmon (Oncorhynchus kisutch) were linearly related. Population effective size was calculated by using estimated means and variances of family size in a 25-yr data set. Although numbers of age 3 adults returning to the hatchery appeared to be large enough to avoid inbreeding problems (the 25-yr mean exceeded 4500), the numbers actually contributing to the hatchery production may be too low. Several strategies are proposed to correct the problem perceived. Argument is given to support the contention that the problem of effective size is fairly general and is not confined to the present study population.

  5. Estimating avian population size using Bowden's estimator

    USGS Publications Warehouse

    Diefenbach, D.R.

    2009-01-01

    Avian researchers often uniquely mark birds, and multiple estimators could be used to estimate population size using individually identified birds. However, most estimators of population size require that all sightings of marked birds be uniquely identified, and many assume homogeneous detection probabilities. Bowden's estimator can incorporate sightings of marked birds that are not uniquely identified and relax assumptions required of other estimators. I used computer simulation to evaluate the performance of Bowden's estimator for situations likely to be encountered in bird studies. When the assumptions of the estimator were met, abundance and variance estimates and confidence-interval coverage were accurate. However, precision was poor for small population sizes (N ??? 50) unless a large percentage of the population was marked (>75%) and multiple (???8) sighting surveys were conducted. If additional birds are marked after sighting surveys begin, it is important to initially mark a large proportion of the population (pm ??? 0.5 if N ??? 100 or pm > 0.1 if N ??? 250) and minimize sightings in which birds are not uniquely identified; otherwise, most population estimates will be overestimated by >10%. Bowden's estimator can be useful for avian studies because birds can be resighted multiple times during a single survey, not all sightings of marked birds have to uniquely identify individuals, detection probabilities among birds can vary, and the complete study area does not have to be surveyed. I provide computer code for use with pilot data to design mark-resight surveys to meet desired precision for abundance estimates. ?? 2009 by The American Ornithologists' Union. All rights reserved.

  6. Coexistence of structured populations with size-based prey selection.

    PubMed

    Hartvig, Martin; Andersen, Ken Haste

    2013-11-01

    Species with a large adult-offspring size ratio and a preferred predator-prey mass ratio undergo ontogenetic trophic niche shift(s) throughout life. Trophic interactions between such species vary throughout life, resulting in different species-level interaction motifs depending on the maximum adult sizes and population size distributions. We explore the assembly and potential for coexistence of small communities where all species experience ontogenetic trophic niche shifts. The life-history of each species is described by a physiologically structured model and species identity is characterised by the trait: size at maturation. We show that a single species can exist in two different states: a 'resource driven state' and a 'cannibalistic state' with a large scope for emergent Allee effects and bistable states. Two species can coexist in two different configurations: in a 'competitive coexistence' state when the ratio between sizes at maturation of the two species is less than a predator-prey mass ratio and the resource level is low to intermediate, or in a 'trophic ladder' state if the ratio of sizes at maturation is larger than the predator-prey mass ratio at all resource levels. While there is a large scope for coexistence of two species, the scope for coexistence of three species is limited and we conclude that further trait differentiation is required for coexistence of more species-rich size-structured communities. PMID:23927897

  7. Efficient and Unbiased Estimation of Population Size.

    PubMed

    Cruz, Marcos; Gómez, Domingo; Cruz-Orive, Luis M

    2015-01-01

    Population sizing from still aerial pictures is of wide applicability in ecological and social sciences. The problem is long standing because current automatic detection and counting algorithms are known to fail in most cases, and exhaustive manual counting is tedious, slow, difficult to verify and unfeasible for large populations. An alternative is to multiply population density with some reference area but, unfortunately, sampling details, handling of edge effects, etc., are seldom described. For the first time we address the problem using principles of geometric sampling. These principles are old and solid, but largely unknown outside the areas of three dimensional microscopy and stereology. Here we adapt them to estimate the size of any population of individuals lying on an essentially planar area, e.g. people, animals, trees on a savanna, etc. The proposed design is unbiased irrespective of population size, pattern, perspective artifacts, etc. The implementation is very simple-it is based on the random superimposition of coarse quadrat grids. Also, an objective error assessment is often lacking. For the latter purpose the quadrat counts are often assumed to be independent. We demonstrate that this approach can perform very poorly, and we propose (and check via Monte Carlo resampling) a new theoretical error prediction formula. As far as efficiency, counting about 50 (100) individuals in 20 quadrats, can yield relative standard errors of about 8% (5%) in typical cases. This fact effectively breaks the barrier hitherto imposed by the current lack of automatic face detection algorithms, because semiautomatic sampling and manual counting becomes an attractive option. PMID:26535587

  8. Efficient and Unbiased Estimation of Population Size

    PubMed Central

    Cruz, Marcos; Gómez, Domingo; Cruz-Orive, Luis M.

    2015-01-01

    Population sizing from still aerial pictures is of wide applicability in ecological and social sciences. The problem is long standing because current automatic detection and counting algorithms are known to fail in most cases, and exhaustive manual counting is tedious, slow, difficult to verify and unfeasible for large populations. An alternative is to multiply population density with some reference area but, unfortunately, sampling details, handling of edge effects, etc., are seldom described. For the first time we address the problem using principles of geometric sampling. These principles are old and solid, but largely unknown outside the areas of three dimensional microscopy and stereology. Here we adapt them to estimate the size of any population of individuals lying on an essentially planar area, e.g. people, animals, trees on a savanna, etc. The proposed design is unbiased irrespective of population size, pattern, perspective artifacts, etc. The implementation is very simple—it is based on the random superimposition of coarse quadrat grids. Also, an objective error assessment is often lacking. For the latter purpose the quadrat counts are often assumed to be independent. We demonstrate that this approach can perform very poorly, and we propose (and check via Monte Carlo resampling) a new theoretical error prediction formula. As far as efficiency, counting about 50 (100) individuals in 20 quadrats, can yield relative standard errors of about 8% (5%) in typical cases. This fact effectively breaks the barrier hitherto imposed by the current lack of automatic face detection algorithms, because semiautomatic sampling and manual counting becomes an attractive option. PMID:26535587

  9. Adult height, nutrition, and population health.

    PubMed

    Perkins, Jessica M; Subramanian, S V; Davey Smith, George; Özaltin, Emre

    2016-03-01

    In this review, the potential causes and consequences of adult height, a measure of cumulative net nutrition, in modern populations are summarized. The mechanisms linking adult height and health are examined, with a focus on the role of potential confounders. Evidence across studies indicates that short adult height (reflecting growth retardation) in low- and middle-income countries is driven by environmental conditions, especially net nutrition during early years. Some of the associations of height with health and social outcomes potentially reflect the association between these environmental factors and such outcomes. These conditions are manifested in the substantial differences in adult height that exist between and within countries and over time. This review suggests that adult height is a useful marker of variation in cumulative net nutrition, biological deprivation, and standard of living between and within populations and should be routinely measured. Linkages between adult height and health, within and across generations, suggest that adult height may be a potential tool for monitoring health conditions and that programs focused on offspring outcomes may consider maternal height as a potentially important influence.

  10. An insulin-like peptide regulates size and adult stem cells in planarians.

    PubMed

    Miller, Claire M; Newmark, Phillip A

    2012-01-01

    Animal growth depends on nutritional intake during development. In many animals, nutritional status is uncoupled from moderation of adult stature after adult size is achieved. However, some long-lived animals continue to regulate adult size and fertility in a nutrition-dependent manner. For example, the regenerating flatworm Schmidtea mediterranea becomes smaller, or degrows, during periods of starvation. These animals provide an opportunity to readily observe adult stem cell population dynamics in response to nutritional cues. We explored the role of insulin signaling in S. mediterranea. We disrupted insulin signaling via RNA interference and showed that animals, despite eating, degrew similarly to starved animals. Utilizing in situ hybridization and immunofluorescence, we assessed cellular changes in proliferative populations including the planarian adult stem cell population (neoblasts) and the germline. Both impaired insulin signaling and nutritional deprivation correlated with decreased neoblast proliferation. Additionally, insulin signaling played a role in supporting spermatogenesis that was distinct from the effects of starvation. In sum, we have demonstrated that insulin signaling is responsible for regulation of adult animal size and tissue homeostasis in an organism with plastic adult size. Importantly, insulin signaling continued to affect stem cell and germline populations in a mature organism. Furthermore, we have shown that adult organisms can differentially regulate specific cell populations as a result of environmental challenges.

  11. Long-term effective population size dynamics of an intensively monitored vertebrate population.

    PubMed

    Mueller, A-K; Chakarov, N; Krüger, O; Hoffman, J I

    2016-10-01

    Long-term genetic data from intensively monitored natural populations are important for understanding how effective population sizes (Ne) can vary over time. We therefore genotyped 1622 common buzzard (Buteo buteo) chicks sampled over 12 consecutive years (2002-2013 inclusive) at 15 microsatellite loci. This data set allowed us to both compare single-sample with temporal approaches and explore temporal patterns in the effective number of parents that produced each cohort in relation to the observed population dynamics. We found reasonable consistency between linkage disequilibrium-based single-sample and temporal estimators, particularly during the latter half of the study, but no clear relationship between annual Ne estimates () and census sizes. We also documented a 14-fold increase in between 2008 and 2011, a period during which the census size doubled, probably reflecting a combination of higher adult survival and immigration from further afield. Our study thus reveals appreciable temporal heterogeneity in the effective population size of a natural vertebrate population, confirms the need for long-term studies and cautions against drawing conclusions from a single sample. PMID:27553455

  12. Demographic population model for American shad: will access to additional habitat upstream of dams increase population sizes?

    USGS Publications Warehouse

    Harris, Julianne E.; Hightower, Joseph E.

    2012-01-01

    American shad Alosa sapidissima are in decline in their native range, and modeling possible management scenarios could help guide their restoration. We developed a density-dependent, deterministic, stage-based matrix model to predict the population-level results of transporting American shad to suitable spawning habitat upstream of dams on the Roanoke River, North Carolina and Virginia. We used data on sonic-tagged adult American shad and oxytetracycline-marked American shad fry both above and below dams on the Roanoke River with information from other systems to estimate a starting population size and vital rates. We modeled the adult female population over 30 years under plausible scenarios of adult transport, effective fecundity (egg production), and survival of adults (i.e., to return to spawn the next year) and juveniles (from spawned egg to age 1). We also evaluated the potential effects of increased survival for adults and juveniles. The adult female population size in the Roanoke River was estimated to be 5,224. With no transport, the model predicted a slow population increase over the next 30 years. Predicted population increases were highest when survival was improved during the first year of life. Transport was predicted to benefit the population only if high rates of effective fecundity and juvenile survival could be achieved. Currently, transported adults and young are less likely to successfully out-migrate than individuals below the dams, and the estimated adult population size is much smaller than either of two assumed values of carrying capacity for the lower river; therefore, transport is not predicted to help restore the stock under present conditions. Research on survival rates, density-dependent processes, and the impacts of structures to increase out-migration success would improve evaluation of the potential benefits of access to additional spawning habitat for American shad.

  13. Dissection of complex adult traits in a mouse synthetic population.

    PubMed

    Burke, David T; Kozloff, Kenneth M; Chen, Shu; West, Joshua L; Wilkowski, Jodi M; Goldstein, Steven A; Miller, Richard A; Galecki, Andrzej T

    2012-08-01

    Finding the causative genetic variations that underlie complex adult traits is a significant experimental challenge. The unbiased search strategy of genome-wide association (GWAS) has been used extensively in recent human population studies. These efforts, however, typically find only a minor fraction of the genetic loci that are predicted to affect variation. As an experimental model for the analysis of adult polygenic traits, we measured a mouse population for multiple phenotypes and conducted a genome-wide search for effector loci. Complex adult phenotypes, related to body size and bone structure, were measured as component phenotypes, and each subphenotype was associated with a genomic spectrum of candidate effector loci. The strategy successfully detected several loci for the phenotypes, at genome-wide significance, using a single, modest-sized population (N = 505). The effector loci each explain 2%-10% of the measured trait variation and, taken together, the loci can account for over 25% of a trait's total population variation. A replicate population (N = 378) was used to confirm initially observed loci for one trait (femur length), and, when the two groups were merged, the combined population demonstrated increased power to detect loci. In contrast to human population studies, our mouse genome-wide searches find loci that individually explain a larger fraction of the observed variation. Also, the additive effects of our detected mouse loci more closely match the predicted genetic component of variation. The genetic loci discovered are logical candidates for components of the genetic networks having evolutionary conservation with human biology. PMID:22588897

  14. Constraints on the adult-offspring size relationship in protists.

    PubMed

    Caval-Holme, Franklin; Payne, Jonathan; Skotheim, Jan M

    2013-12-01

    The relationship between adult and offspring size is an important aspect of reproductive strategy. Although this filial relationship has been extensively examined in plants and animals, we currently lack comparable data for protists, whose strategies may differ due to the distinct ecological and physiological constraints on single-celled organisms. Here, we report measurements of adult and offspring sizes in 3888 species and subspecies of foraminifera, a class of large marine protists. Foraminifera exhibit a wide range of reproductive strategies; species of similar adult size may have offspring whose sizes vary 100-fold. Yet, a robust pattern emerges. The minimum (5th percentile), median, and maximum (95th percentile) offspring sizes exhibit a consistent pattern of increase with adult size independent of environmental change and taxonomic variation over the past 400 million years. The consistency of this pattern may arise from evolutionary optimization of the offspring size-fecundity trade-off and/or from cell-biological constraints that limit the range of reproductive strategies available to single-celled organisms. When compared with plants and animals, foraminifera extend the evidence that offspring size covaries with adult size across an additional five orders of magnitude in organism size.

  15. Effective Size of Populations under Selection

    PubMed Central

    Santiago, E.; Caballero, A.

    1995-01-01

    Equations to approximate the effective size (N(e)) of populations under continued selection are obtained that include the possibility of partial full-sib mating and other systems such as assortative mating. The general equation for the case of equal number of sexes and constant number of breeding individuals (N) is N(e) = 4N/[2(1 - α(I)) + (S(k)(2) + 4Q(2)C(2)) (1 + α(I) + 2α(O))], where S(k)(2) is the variance of family size due to sampling without selection, C(2) is the variance of selective advantages among families (the squared coefficient of variation of the expected number of offspring per family), α(I) is the deviation from Hardy-Weinberg proportions, α(O) is the correlation between genes of male and female parents, and Q(2) is the term accounting for the cumulative effect of selection on an inherited trait. This is obtained as Q = 2/[2 - G(1 + r)], where G is the remaining proportion of genetic variance in selected individuals and r is the correlation of the expected selective values of male and female parents. The method is also extended to the general case of different numbers of male and female parents. The predictive value of the formulae is tested under a model of truncation selection with the infinitesimal model of gene effects, where C(2) and G are a function of the selection intensity, the heritability and the intraclass correlation of sibs. Under random mating r = α(I) = -1/(N - 1) and α(O) = 0. Under partial full-sib mating with an average proportion β of full-sib matings per generation, r & β and α(O) & α(I) & β/ (4 - 3β). The prediction equation is compared to other approximations based on the long-term contributions of ancestors to descendants. Finally, based on the approach followed, a system of mating (compensatory mating) is proposed to reduce rates of inbreeding without loss of response in selection programs in which selected individuals from the largest families are mated to those from the smallest families. PMID:7713405

  16. Assessment of Aedes albopictus (Skuse) (Diptera: Culicidae) clutch size in wild and laboratory populations.

    PubMed

    Davis, Timothy J; Kline, Daniel L; Kaufman, Phillip E

    2016-06-01

    Aedes albopictus (Skuse) is an invasive mosquito species found across the southern U.S. with range expansion into many northern states. Intra- and interspecific larval competition have been evaluated for Ae. albopictus with respect to subsequent adult size, immature and adult survivability, and its capacity to vector pathogens as an adult. However, limited data are available on egg production as related to larval rearing conditions. Because Ae. albopictus is a container-inhabiting mosquito that oviposits in resource-limited habitats, it is found under variable density-dependent conditions. Therefore, we examined the impact of specific rearing conditions on Ae. albopictus clutch size and adult body size; comparing the egg production values and wing lengths from known developmental densities to those from field-collected populations. Field populations varied significantly among collection sites in mean clutch size (23 to 46). These clutch sizes were comparable to the mean clutch sizes of females reared at the larval densities of nine (20 eggs) and three (53 eggs) larvae per 3 ml of water in the laboratory. Field populations experienced density-dependent effects impacting adult mosquito size. Mosquitoes from the four sample sites had mean wing lengths of 1.99, 2.47, 2.51, and 2.54 mm, which were less than the mean wing length of mosquitoes reared at larval densities of three larvae per 3 ml of water (2.57 mm). PMID:27232119

  17. 21 CFR 312.315 - Intermediate-size patient populations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 5 2011-04-01 2011-04-01 false Intermediate-size patient populations. 312.315... for Treatment Use § 312.315 Intermediate-size patient populations. Under this section, FDA may permit an investigational drug to be used for the treatment of a patient population smaller than...

  18. 21 CFR 312.315 - Intermediate-size patient populations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 5 2014-04-01 2014-04-01 false Intermediate-size patient populations. 312.315... for Treatment Use § 312.315 Intermediate-size patient populations. Under this section, FDA may permit an investigational drug to be used for the treatment of a patient population smaller than...

  19. 21 CFR 312.315 - Intermediate-size patient populations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 5 2013-04-01 2013-04-01 false Intermediate-size patient populations. 312.315... for Treatment Use § 312.315 Intermediate-size patient populations. Under this section, FDA may permit an investigational drug to be used for the treatment of a patient population smaller than...

  20. 21 CFR 312.315 - Intermediate-size patient populations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 5 2012-04-01 2012-04-01 false Intermediate-size patient populations. 312.315... for Treatment Use § 312.315 Intermediate-size patient populations. Under this section, FDA may permit an investigational drug to be used for the treatment of a patient population smaller than...

  1. Anaphylaxis in the young adult population.

    PubMed

    Gupta, Ruchi S

    2014-01-01

    It is critical that clinicians treating young adults understand the presentation and management of anaphylaxis. The most common trigger for anaphylaxis in this population is food. The prevalence of food allergy is growing, with 8% of US children and adolescents affected. All patients at risk for anaphylaxis should be prescribed epinephrine autoinjectors, as epinephrine is the only life-saving medication for a severe anaphylactic reaction. The presentation of anaphylaxis can involve multiple organ systems (eg, mucocutaneous, respiratory, cardiovascular, gastrointestinal) and, as such, patient education is needed to assist in prompt recognition. Appropriate training of patients and caregivers about how to identify anaphylaxis and what to do in an emergency is critical. Training of school and college staff also is essential, as 1 in 4 first-time reactions occurs outside the home. Additional counseling for adolescents at risk for anaphylactic reactions should address increased risk-taking behavior, decreased adult supervision, dating, and the transition of disease management from an adult to the patient.

  2. Prevalence of sleepwalking in an adult population

    PubMed Central

    Mume, Celestine Okorome

    2010-01-01

    Background Sleepwalking consists of a series of behavioral activities that occur during sleep. These activities may be simple, complex or aggressive in nature. They include motor activities, confusion, and amnesia for the events. Sleepwalking is a disorder of arousal from non-rapid eye movement (NREM) sleep. In children, episodes of sleepwalking are rarely violent; in adults, however, sleepwalking might include violence, which could endanger the patient or others and might precipitate legal issues. There is inadequate information on the prevalence and demographic correlates of sleepwalking in Nigeria. Objectives One objective of this study was to determine the lifetime prevalence rate of sleepwalking in an adult population in Ile-Ife, in Southwestern Nigeria. Another objective was to determine the age and sex distribution of sleepwalking among those who have experienced it at least once in their lifetime. Materials and Methods A random sample of 228 healthy individuals aged 18–60 years was obtained and the members were asked to fill out a survey form about lifetime prevalence rate of sleepwalking. Results The overall lifetime prevalence rate of sleepwalking was 7% (16 of 228 participants). It was 10.4% in males and 3.5% in females, but the difference was not statistically significant (p=0.07). Conclusion This study has shown that sleepwalking is common in the population. In view of the psychological effects of sleepwalking and the potential physical and legal problems associated with it, adequate efforts should be made for early detection and prompt management of the condition. PMID:21483553

  3. Sample-size requirements for evaluating population size structure

    USGS Publications Warehouse

    Vokoun, J.C.; Rabeni, C.F.; Stanovick, J.S.

    2001-01-01

    A method with an accompanying computer program is described to estimate the number of individuals needed to construct a sample length-frequency with a given accuracy and precision. First, a reference length-frequency assumed to be accurate for a particular sampling gear and collection strategy was constructed. Bootstrap procedures created length-frequencies with increasing sample size that were randomly chosen from the reference data and then were compared with the reference length-frequency by calculating the mean squared difference. Outputs from two species collected with different gears and an artificial even length-frequency are used to describe the characteristics of the method. The relations between the number of individuals used to construct a length-frequency and the similarity to the reference length-frequency followed a negative exponential distribution and showed the importance of using 300-400 individuals whenever possible.

  4. A phylogenetic analysis of egg size, clutch size, spawning mode, adult body size, and latitude in reef fishes

    NASA Astrophysics Data System (ADS)

    Kasimatis, Katja; Riginos, Cynthia

    2016-06-01

    Theoretical treatments of egg size in fishes suggest that constraints on reproductive output should create trade-offs between the size and number of eggs produced per spawn. For marine reef fishes, the observation of distinct reproductive care strategies (demersal guarding, egg scattering, and pelagic spawning) has additionally prompted speculation that these strategies reflect alternative fitness optima with selection on egg size differing by reproductive mode and perhaps latitude. Here, we aggregate data from 278 reef fish species and test whether clutch size, reproductive care, adult body size, and latitudinal bands (i.e., tropical, subtropical, and temperate) predict egg size, using a statistically unified framework that accounts for phylogenetic correlations among traits. We find no inverse relationship between species egg size and clutch size, but rather that egg size differs by reproductive mode (mean volume for demersal eggs = 1.22 mm3, scattered eggs = 0.18 mm3, pelagic eggs = 0.52 mm3) and that clutch size is strongly correlated with adult body size. Larger eggs were found in temperate species compared with tropical species in both demersal guarders and pelagic spawners, but this difference was not strong when accounting for phylogenetic correlations, suggesting that differences in species composition underlies regional differences in egg size. In summary, demersal guarders are generally small fishes with small clutch sizes that produce large eggs. Pelagic spawners and egg scatterers are variable in adult and clutch size. Although pelagic spawned eggs are variable in size, those of scatterers are consistently small.

  5. Population size predicts technological complexity in Oceania

    PubMed Central

    Kline, Michelle A.; Boyd, Robert

    2010-01-01

    Much human adaptation depends on the gradual accumulation of culturally transmitted knowledge and technology. Recent models of this process predict that large, well-connected populations will have more diverse and complex tool kits than small, isolated populations. While several examples of the loss of technology in small populations are consistent with this prediction, it found no support in two systematic quantitative tests. Both studies were based on data from continental populations in which contact rates were not available, and therefore these studies do not provide a test of the models. Here, we show that in Oceania, around the time of early European contact, islands with small populations had less complicated marine foraging technology. This finding suggests that explanations of existing cultural variation based on optimality models alone are incomplete because demography plays an important role in generating cumulative cultural adaptation. It also indicates that hominin populations with similar cognitive abilities may leave very different archaeological records, a conclusion that has important implications for our understanding of the origin of anatomically modern humans and their evolved psychology. PMID:20392733

  6. Comparing population size estimators for plethodontid salamanders

    USGS Publications Warehouse

    Bailey, L.L.; Simons, T.R.; Pollock, K.H.

    2004-01-01

    Despite concern over amphibian declines, few studies estimate absolute abundances because of logistic and economic constraints and previously poor estimator performance. Two estimation approaches recommended for amphibian studies are mark-recapture and depletion (or removal) sampling. We compared abundance estimation via various mark-recapture and depletion methods, using data from a three-year study of terrestrial salamanders in Great Smoky Mountains National Park. Our results indicate that short-term closed-population, robust design, and depletion methods estimate surface population of salamanders (i.e., those near the surface and available for capture during a given sampling occasion). In longer duration studies, temporary emigration violates assumptions of both open- and closed-population mark-recapture estimation models. However, if the temporary emigration is completely random, these models should yield unbiased estimates of the total population (superpopulation) of salamanders in the sampled area. We recommend using Pollock's robust design in mark-recapture studies because of its flexibility to incorporate variation in capture probabilities and to estimate temporary emigration probabilities.

  7. Repeated Habitat Disturbances by Fire Decrease Local Effective Population Size.

    PubMed

    Schrey, Aaron W; Ragsdale, Alexandria K; McCoy, Earl D; Mushinsky, Henry R

    2016-07-01

    Effective population size is a fundamental parameter in population genetics, and factors that alter effective population size will shape the genetic characteristics of populations. Habitat disturbance may have a large effect on genetic characteristics of populations by influencing immigration and gene flow, particularly in fragmented habitats. We used the Florida Sand Skink (Plestiodon reynoldsi) to investigate the effect of fire-based habitat disturbances on the effective population size in the highly threatened, severely fragmented, and fire dependent Florida scrub habitat. We screened 7 microsatellite loci in 604 individuals collected from 12 locations at Archbold Biological Station. Archbold Biological Station has an active fire management plan and detailed records of fires dating to 1967. Our objective was to determine how the timing, number, and intervals between fires affect effective population size, focusing on multiple fires in the same location. Effective population size was higher in areas that had not been burned for more than 10 years and decreased with number of fires and shorter time between fires. A similar pattern was observed in abundance: increasing abundance with time-since-fire and decreasing abundance with number of fires. The ratio of effective population size to census size was higher at sites with more recent fires and tended to decrease with time-since-last-fire. These results suggest that habitat disturbances, such as fire, may have a large effect in the genetic characteristics of local populations and that Florida Sand Skinks are well adapted to the natural fire dynamics required to maintain Florida scrub.

  8. Lifetime selection on adult body size and components of body size in a waterstrider: opposing selection and maintenance of sexual size dimorphism.

    PubMed

    Preziosi, R F; Fairbairn, D J

    2000-04-01

    Sexual size dimorphism (SSD), the difference in body size between males and females, is common in almost all taxa of animals and is generally assumed to be adaptive. Although sexual selection and fecundity selection alone have often been invoked to explain the evolution of SSD, more recent views indicate that the sexes must experience different lifetime selection pressures for SSD to evolve and be maintained. We estimated selection acting on male and female adult body size (total length) and components of body size in the waterstrider Aquarius remigis during three phases of life history. Opposing selection pressures for overall body size occurred in separate episodes of fitness for females in both years and for males in one year. Specific components of body size were often the targets of the selection on overall body size. When net adult fitness was estimated by combining each individual's fitnesses from all episodes, we found stabilizing selection in both sexes. In addition, the net optimum overall body size of males was smaller than that of females. However, even when components of body size had experienced opposing selection pressures in individual episodes, no components appeared to be under lifetime stabilizing selection. This is the first evidence that contemporary selection in a natural population acts to maintain female size larger than male size, the most common pattern of SSD in nature.

  9. Evolutionary dynamics with fluctuating population sizes and strong mutualism

    NASA Astrophysics Data System (ADS)

    Chotibut, Thiparat; Nelson, David R.

    2015-08-01

    Game theory ideas provide a useful framework for studying evolutionary dynamics in a well-mixed environment. This approach, however, typically enforces a strictly fixed overall population size, deemphasizing natural growth processes. We study a competitive Lotka-Volterra model, with number fluctuations, that accounts for natural population growth and encompasses interaction scenarios typical of evolutionary games. We show that, in an appropriate limit, the model describes standard evolutionary games with both genetic drift and overall population size fluctuations. However, there are also regimes where a varying population size can strongly influence the evolutionary dynamics. We focus on the strong mutualism scenario and demonstrate that standard evolutionary game theory fails to describe our simulation results. We then analytically and numerically determine fixation probabilities as well as mean fixation times using matched asymptotic expansions, taking into account the population size degree of freedom. These results elucidate the interplay between population dynamics and evolutionary dynamics in well-mixed systems.

  10. Evolutionary dynamics with fluctuating population sizes and strong mutualism.

    PubMed

    Chotibut, Thiparat; Nelson, David R

    2015-08-01

    Game theory ideas provide a useful framework for studying evolutionary dynamics in a well-mixed environment. This approach, however, typically enforces a strictly fixed overall population size, deemphasizing natural growth processes. We study a competitive Lotka-Volterra model, with number fluctuations, that accounts for natural population growth and encompasses interaction scenarios typical of evolutionary games. We show that, in an appropriate limit, the model describes standard evolutionary games with both genetic drift and overall population size fluctuations. However, there are also regimes where a varying population size can strongly influence the evolutionary dynamics. We focus on the strong mutualism scenario and demonstrate that standard evolutionary game theory fails to describe our simulation results. We then analytically and numerically determine fixation probabilities as well as mean fixation times using matched asymptotic expansions, taking into account the population size degree of freedom. These results elucidate the interplay between population dynamics and evolutionary dynamics in well-mixed systems. PMID:26382443

  11. Population size, pollination and phenotypic trait selection in Phyteuma spicatum

    NASA Astrophysics Data System (ADS)

    Weber, Anne; Kolb, Annette

    2013-02-01

    Plants in small populations may receive fewer visits, smaller pollen loads or pollen of poorer quality and suffer from reduced reproductive success compared to plants in larger populations. Consequently, pollen limitation of plants in small populations has been suggested to result in the evolution of reduced reliance on pollinators or the enhancement of traits that attract pollinators. The main aim of this study was to experimentally quantify the strength of pollinator-mediated selection on floral display size and flowering phenology in populations of varying size, using the self-incompatible, perennial herb Phyteuma spicatum as study species. We conducted supplementary hand pollinations in six populations (ranging in size between ca. 20-3000 flowering individuals) over two consecutive years and assessed selection gradients (i.e., trait-fitness relationships) in open- and hand-pollinated plants. Our results show that some populations are pollen limited in some years, but, contrary to our expectation, the degree of pollen limitation was not significantly related to population size. We found phenotypic selection for increased inflorescence size (in most populations and in both years), but we obtained no or no strong evidence that selection was pollinator-mediated or that the strength of selection was related to population size. This may have been the result of low statistical power, an inherent problem of studies examining effects of population size that require the inclusion of populations with only few individuals. In addition, given that selection appeared to be spatially and temporally variable, abiotic or biotic factors other than pollinators may have contributed to selection on inflorescence size.

  12. Rapid population divergence in thermal reaction norms for an invading species: breaking the temperature-size rule.

    PubMed

    Kingsolver, J G; Massie, K R; Ragland, G J; Smith, M H

    2007-05-01

    The temperature-size rule is a common pattern of phenotypic plasticity in which higher temperature during development results in a smaller adult body size (i.e. a thermal reaction norm with negative slope). Examples and exceptions to the rule are known in multiple groups of organisms, but rapid population differentiation in the temperature-size rule has not been explored. Here we examine the genetic and parental contributions to population differentiation in thermal reaction norms for size, development time and survival in the Cabbage White Butterfly Pieris rapae, for two geographical populations that have likely diverged within the past 150 years. We used split-sibship experiments with two temperature treatments (warm and cool) for P. rapae from Chapel Hill, NC, and from Seattle, WA. Mixed-effect model analyses demonstrate significant genetic differences between NC and WA populations for adult size and for thermal reaction norms for size. Mean adult mass was 12-24% greater in NC than in WA populations for both temperature treatments; mean size was unaffected or decreased with temperature (the temperature-size rule) for the WA population, but size increased with temperature for the NC population. Our study shows that the temperature-size rule and related thermal reaction norms can evolve rapidly within species in natural field conditions. Rapid evolutionary divergence argues against the existence of a simple, general mechanistic constraint as the underlying cause of the temperature-size rule.

  13. Andean Condor (Vultur gryphus) in Ecuador: Geographic Distribution, Population Size and Extinction Risk.

    PubMed

    Naveda-Rodríguez, Adrián; Vargas, Félix Hernán; Kohn, Sebastián; Zapata-Ríos, Galo

    2016-01-01

    The Andean Condor (Vultur gryphus) in Ecuador is classified as Critically Endangered. Before 2015, standardized and systematic estimates of geographic distribution, population size and structure were not available for this species, hampering the assessment of its current status and hindering the design and implementation of effective conservation actions. In this study, we performed the first quantitative assessment of geographic distribution, population size and population viability of Andean Condor in Ecuador. We used a methodological approach that included an ecological niche model to study geographic distribution, a simultaneous survey of 70 roosting sites to estimate population size and a population viability analysis (PVA) for the next 100 years. Geographic distribution in the form of extent of occurrence was 49 725 km2. During a two-day census, 93 Andean Condors were recorded and a population of 94 to 102 individuals was estimated. In this population, adult-to-immature ratio was 1:0.5. In the modeled PVA scenarios, the probability of extinction, mean time to extinction and minimum population size varied from zero to 100%, 63 years and 193 individuals, respectively. Habitat loss is the greatest threat to the conservation of Andean Condor populations in Ecuador. Population size reduction in scenarios that included habitat loss began within the first 15 years of this threat. Population reinforcement had no effects on the recovery of Andean Condor populations given the current status of the species in Ecuador. The population size estimate presented in this study is the lower than those reported previously in other countries where the species occur. The inferences derived from the population viability analysis have implications for Condor management in Ecuador. This study highlights the need to redirect efforts from captive breeding and population reinforcement to habitat conservation. PMID:26986004

  14. Andean Condor (Vultur gryphus) in Ecuador: Geographic Distribution, Population Size and Extinction Risk

    PubMed Central

    Naveda-Rodríguez, Adrián; Vargas, Félix Hernán; Kohn, Sebastián; Zapata-Ríos, Galo

    2016-01-01

    The Andean Condor (Vultur gryphus) in Ecuador is classified as Critically Endangered. Before 2015, standardized and systematic estimates of geographic distribution, population size and structure were not available for this species, hampering the assessment of its current status and hindering the design and implementation of effective conservation actions. In this study, we performed the first quantitative assessment of geographic distribution, population size and population viability of Andean Condor in Ecuador. We used a methodological approach that included an ecological niche model to study geographic distribution, a simultaneous survey of 70 roosting sites to estimate population size and a population viability analysis (PVA) for the next 100 years. Geographic distribution in the form of extent of occurrence was 49 725 km2. During a two-day census, 93 Andean Condors were recorded and a population of 94 to 102 individuals was estimated. In this population, adult-to-immature ratio was 1:0.5. In the modeled PVA scenarios, the probability of extinction, mean time to extinction and minimum population size varied from zero to 100%, 63 years and 193 individuals, respectively. Habitat loss is the greatest threat to the conservation of Andean Condor populations in Ecuador. Population size reduction in scenarios that included habitat loss began within the first 15 years of this threat. Population reinforcement had no effects on the recovery of Andean Condor populations given the current status of the species in Ecuador. The population size estimate presented in this study is the lower than those reported previously in other countries where the species occur. The inferences derived from the population viability analysis have implications for Condor management in Ecuador. This study highlights the need to redirect efforts from captive breeding and population reinforcement to habitat conservation. PMID:26986004

  15. Andean Condor (Vultur gryphus) in Ecuador: Geographic Distribution, Population Size and Extinction Risk.

    PubMed

    Naveda-Rodríguez, Adrián; Vargas, Félix Hernán; Kohn, Sebastián; Zapata-Ríos, Galo

    2016-01-01

    The Andean Condor (Vultur gryphus) in Ecuador is classified as Critically Endangered. Before 2015, standardized and systematic estimates of geographic distribution, population size and structure were not available for this species, hampering the assessment of its current status and hindering the design and implementation of effective conservation actions. In this study, we performed the first quantitative assessment of geographic distribution, population size and population viability of Andean Condor in Ecuador. We used a methodological approach that included an ecological niche model to study geographic distribution, a simultaneous survey of 70 roosting sites to estimate population size and a population viability analysis (PVA) for the next 100 years. Geographic distribution in the form of extent of occurrence was 49 725 km2. During a two-day census, 93 Andean Condors were recorded and a population of 94 to 102 individuals was estimated. In this population, adult-to-immature ratio was 1:0.5. In the modeled PVA scenarios, the probability of extinction, mean time to extinction and minimum population size varied from zero to 100%, 63 years and 193 individuals, respectively. Habitat loss is the greatest threat to the conservation of Andean Condor populations in Ecuador. Population size reduction in scenarios that included habitat loss began within the first 15 years of this threat. Population reinforcement had no effects on the recovery of Andean Condor populations given the current status of the species in Ecuador. The population size estimate presented in this study is the lower than those reported previously in other countries where the species occur. The inferences derived from the population viability analysis have implications for Condor management in Ecuador. This study highlights the need to redirect efforts from captive breeding and population reinforcement to habitat conservation.

  16. Bayesian Nonparametric Inference of Population Size Changes from Sequential Genealogies.

    PubMed

    Palacios, Julia A; Wakeley, John; Ramachandran, Sohini

    2015-09-01

    Sophisticated inferential tools coupled with the coalescent model have recently emerged for estimating past population sizes from genomic data. Recent methods that model recombination require small sample sizes, make constraining assumptions about population size changes, and do not report measures of uncertainty for estimates. Here, we develop a Gaussian process-based Bayesian nonparametric method coupled with a sequentially Markov coalescent model that allows accurate inference of population sizes over time from a set of genealogies. In contrast to current methods, our approach considers a broad class of recombination events, including those that do not change local genealogies. We show that our method outperforms recent likelihood-based methods that rely on discretization of the parameter space. We illustrate the application of our method to multiple demographic histories, including population bottlenecks and exponential growth. In simulation, our Bayesian approach produces point estimates four times more accurate than maximum-likelihood estimation (based on the sum of absolute differences between the truth and the estimated values). Further, our method's credible intervals for population size as a function of time cover 90% of true values across multiple demographic scenarios, enabling formal hypothesis testing about population size differences over time. Using genealogies estimated with ARGweaver, we apply our method to European and Yoruban samples from the 1000 Genomes Project and confirm key known aspects of population size history over the past 150,000 years. PMID:26224734

  17. Estimation of population size using open capture-recapture models

    USGS Publications Warehouse

    McDonald, T.L.; Amstrup, Steven C.

    2001-01-01

    One of the most important needs for wildlife managers is an accurate estimate of population size. Yet, for many species, including most marine species and large mammals, accurate and precise estimation of numbers is one of the most difficult of all research challenges. Open-population capture-recapture models have proven useful in many situations to estimate survival probabilities but typically have not been used to estimate population size. We show that open-population models can be used to estimate population size by developing a Horvitz-Thompson-type estimate of population size and an estimator of its variance. Our population size estimate keys on the probability of capture at each trap occasion and therefore is quite general and can be made a function of external covariates measured during the study. Here we define the estimator and investigate its bias, variance, and variance estimator via computer simulation. Computer simulations make extensive use of real data taken from a study of polar bears (Ursus maritimus) in the Beaufort Sea. The population size estimator is shown to be useful because it was negligibly biased in all situations studied. The variance estimator is shown to be useful in all situations, but caution is warranted in cases of extreme capture heterogeneity.

  18. Drift load in populations of small size and low density.

    PubMed

    Willi, Y; Griffin, P; Van Buskirk, J

    2013-03-01

    According to theory, drift load in randomly mating populations is determined by past population size, because enhanced genetic drift in small populations causes accumulation and fixation of recessive deleterious mutations of small effect. In contrast, segregating load due to mutations of low frequency should decline in smaller populations, at least when mutations are highly recessive and strongly deleterious. Strong local selection generally reduces both types of load. We tested these predictions in 13 isolated, outcrossing populations of Arabidopsis lyrata that varied in population size and plant density. Long-term size was estimated by expected heterozygosity at 20 microsatellite loci. Segregating load was assessed by comparing performance of offspring from selfings versus within-population crosses. Drift load was the heterosis effect created by interpopulation outbreeding. Results showed that segregating load was unrelated to long-term size. However, drift load was significantly higher in populations of small effective size and low density. Drift load was mostly expressed late in development, but started as early as germination and accumulated thereafter. The study largely confirms predictions of theory and illustrates that mutation accumulation can be a threat to natural populations.

  19. Size & Flow: Adult Education Issues in the Senate Immigration Bill

    ERIC Educational Resources Information Center

    Murphy, Garrett; Spangenberg, Gail

    2014-01-01

    In this essay Garrett Murphy and Gail Spangenberg report on the need for understanding better than in the past, the number of undocumented immigrants likely to need adult education services under provisions of Senate Immigration Bill S.744. The essay looks at why the issues of "size and flow" are important for planners, providers, and…

  20. On population size estimators in the Poisson mixture model.

    PubMed

    Mao, Chang Xuan; Yang, Nan; Zhong, Jinhua

    2013-09-01

    Estimating population sizes via capture-recapture experiments has enormous applications. The Poisson mixture model can be adopted for those applications with a single list in which individuals appear one or more times. We compare several nonparametric estimators, including the Chao estimator, the Zelterman estimator, two jackknife estimators and the bootstrap estimator. The target parameter of the Chao estimator is a lower bound of the population size. Those of the other four estimators are not lower bounds, and they may produce lower confidence limits for the population size with poor coverage probabilities. A simulation study is reported and two examples are investigated. PMID:23865502

  1. On population size estimators in the Poisson mixture model.

    PubMed

    Mao, Chang Xuan; Yang, Nan; Zhong, Jinhua

    2013-09-01

    Estimating population sizes via capture-recapture experiments has enormous applications. The Poisson mixture model can be adopted for those applications with a single list in which individuals appear one or more times. We compare several nonparametric estimators, including the Chao estimator, the Zelterman estimator, two jackknife estimators and the bootstrap estimator. The target parameter of the Chao estimator is a lower bound of the population size. Those of the other four estimators are not lower bounds, and they may produce lower confidence limits for the population size with poor coverage probabilities. A simulation study is reported and two examples are investigated.

  2. A Meta-Analysis of Dunn and Dunn Model Correlational Research with Adult Populations

    ERIC Educational Resources Information Center

    Mangino, Christine

    2004-01-01

    The purpose of this investigation was to conduct a quantitative synthesis of correlational research that focused on the Dunn and Dunn Learning-Style Model and was concerned with adult populations. A total of 8,661 participants from the 47 original investigations provided 386 individual effect sizes for this meta-analysis. The mean effect size was…

  3. Repeatability of adaptation in experimental populations of different sizes

    PubMed Central

    Lachapelle, Josianne; Reid, Joshua; Colegrave, Nick

    2015-01-01

    The degree to which evolutionary trajectories and outcomes are repeatable across independent populations depends on the relative contribution of selection, chance and history. Population size has been shown theoretically and empirically to affect the amount of variation that arises among independent populations adapting to the same environment. Here, we measure the contribution of selection, chance and history in different-sized experimental populations of the unicellular alga Chlamydomonas reinhardtii adapting to a high salt environment to determine which component of evolution is affected by population size. We find that adaptation to salt is repeatable at the fitness level in medium (Ne = 5 × 104) and large (Ne = 4 × 105) populations because of the large contribution of selection. Adaptation is not repeatable in small (Ne = 5 × 103) populations because of large constraints from history. The threshold between stochastic and deterministic evolution in this case is therefore between effective population sizes of 103 and 104. Our results indicate that diversity across populations is more likely to be maintained if they are small. Experimental outcomes in large populations are likely to be robust and can inform our predictions about outcomes in similar situations. PMID:25788593

  4. Effects of host-plant population size and plant sex on a specialist leaf-miner

    NASA Astrophysics Data System (ADS)

    Bañuelos, María-José; Kollmann, Johannes

    2011-03-01

    Animal population density has been related to resource patch size through various hypotheses such as those derived from island biogeography and resource concentration theory. This theoretical framework can be also applied to plant-herbivore interactions, and it can be modified by the sex of the host-plant, and density-dependent relationships. Leaf-miners are specialised herbivores that leave distinct traces on infested leaves in the form of egg scars, mines, signs of predation and emergence holes. This allows the life cycle of the insect to be reconstructed and the success at the different stages to be estimated. The main stages of the leaf-miner Phytomyza ilicis were recorded in eleven populations of the evergreen host Ilex aquifolium in Denmark. Survival rates were calculated and related to population size, sex of the host plant, and egg and mine densities. Host population size was negatively related to leaf-miner prevalence, with larger egg and mine densities in small populations. Percentage of eggs hatching and developing into mines, and percentage of adult flies emerging from mines also differed among host populations, but were not related to population size or host cover. Feeding punctures left by adults were marginally more frequent on male plants, whereas egg scars and mines were more common on females. Overall survival rate from egg stage to adult emergence was higher on female plants. Egg density was negatively correlated with hatching, while mine density was positively correlated with emergence of the larvae. The inverse effects of host population size were not in line with predictions based on island biogeography and resource concentration theory. We discuss how a thorough knowledge of the immigration behaviour of this fly might help to understand the patterns found.

  5. Adult and larval traits as determinants of geographic range size among tropical reef fishes

    PubMed Central

    Luiz, Osmar J.; Allen, Andrew P.; Robertson, D. Ross; Floeter, Sergio R.; Kulbicki, Michel; Vigliola, Laurent; Becheler, Ronan; Madin, Joshua S.

    2013-01-01

    Most marine organisms disperse via ocean currents as larvae, so it is often assumed that larval-stage duration is the primary determinant of geographic range size. However, empirical tests of this relationship have yielded mixed results, and alternative hypotheses have rarely been considered. Here we assess the relative influence of adult and larval-traits on geographic range size using a global dataset encompassing 590 species of tropical reef fishes in 47 families, the largest compilation of such data to date for any marine group. We analyze this database using linear mixed-effect models to control for phylogeny and geographical limits on range size. Our analysis indicates that three adult traits likely to affect the capacity of new colonizers to survive and establish reproductive populations (body size, schooling behavior, and nocturnal activity) are equal or better predictors of geographic range size than pelagic larval duration. We conclude that adult life-history traits that affect the postdispersal persistence of new populations are primary determinants of successful range extension and, consequently, of geographic range size among tropical reef fishes. PMID:24065830

  6. Adult and larval traits as determinants of geographic range size among tropical reef fishes.

    PubMed

    Luiz, Osmar J; Allen, Andrew P; Robertson, D Ross; Floeter, Sergio R; Kulbicki, Michel; Vigliola, Laurent; Becheler, Ronan; Madin, Joshua S

    2013-10-01

    Most marine organisms disperse via ocean currents as larvae, so it is often assumed that larval-stage duration is the primary determinant of geographic range size. However, empirical tests of this relationship have yielded mixed results, and alternative hypotheses have rarely been considered. Here we assess the relative influence of adult and larval-traits on geographic range size using a global dataset encompassing 590 species of tropical reef fishes in 47 families, the largest compilation of such data to date for any marine group. We analyze this database using linear mixed-effect models to control for phylogeny and geographical limits on range size. Our analysis indicates that three adult traits likely to affect the capacity of new colonizers to survive and establish reproductive populations (body size, schooling behavior, and nocturnal activity) are equal or better predictors of geographic range size than pelagic larval duration. We conclude that adult life-history traits that affect the postdispersal persistence of new populations are primary determinants of successful range extension and, consequently, of geographic range size among tropical reef fishes.

  7. The evolutionary legacy of size-selective harvesting extends from genes to populations

    PubMed Central

    Uusi-Heikkilä, Silva; Whiteley, Andrew R; Kuparinen, Anna; Matsumura, Shuichi; Venturelli, Paul A; Wolter, Christian; Slate, Jon; Primmer, Craig R; Meinelt, Thomas; Killen, Shaun S; Bierbach, David; Polverino, Giovanni; Ludwig, Arne; Arlinghaus, Robert

    2015-01-01

    Size-selective harvesting is assumed to alter life histories of exploited fish populations, thereby negatively affecting population productivity, recovery, and yield. However, demonstrating that fisheries-induced phenotypic changes in the wild are at least partly genetically determined has proved notoriously difficult. Moreover, the population-level consequences of fisheries-induced evolution are still being controversially discussed. Using an experimental approach, we found that five generations of size-selective harvesting altered the life histories and behavior, but not the metabolic rate, of wild-origin zebrafish (Danio rerio). Fish adapted to high positively size selective fishing pressure invested more in reproduction, reached a smaller adult body size, and were less explorative and bold. Phenotypic changes seemed subtle but were accompanied by genetic changes in functional loci. Thus, our results provided unambiguous evidence for rapid, harvest-induced phenotypic and evolutionary change when harvesting is intensive and size selective. According to a life-history model, the observed life-history changes elevated population growth rate in harvested conditions, but slowed population recovery under a simulated moratorium. Hence, the evolutionary legacy of size-selective harvesting includes populations that are productive under exploited conditions, but selectively disadvantaged to cope with natural selection pressures that often favor large body size. PMID:26136825

  8. The evolutionary legacy of size-selective harvesting extends from genes to populations.

    PubMed

    Uusi-Heikkilä, Silva; Whiteley, Andrew R; Kuparinen, Anna; Matsumura, Shuichi; Venturelli, Paul A; Wolter, Christian; Slate, Jon; Primmer, Craig R; Meinelt, Thomas; Killen, Shaun S; Bierbach, David; Polverino, Giovanni; Ludwig, Arne; Arlinghaus, Robert

    2015-07-01

    Size-selective harvesting is assumed to alter life histories of exploited fish populations, thereby negatively affecting population productivity, recovery, and yield. However, demonstrating that fisheries-induced phenotypic changes in the wild are at least partly genetically determined has proved notoriously difficult. Moreover, the population-level consequences of fisheries-induced evolution are still being controversially discussed. Using an experimental approach, we found that five generations of size-selective harvesting altered the life histories and behavior, but not the metabolic rate, of wild-origin zebrafish (Danio rerio). Fish adapted to high positively size selective fishing pressure invested more in reproduction, reached a smaller adult body size, and were less explorative and bold. Phenotypic changes seemed subtle but were accompanied by genetic changes in functional loci. Thus, our results provided unambiguous evidence for rapid, harvest-induced phenotypic and evolutionary change when harvesting is intensive and size selective. According to a life-history model, the observed life-history changes elevated population growth rate in harvested conditions, but slowed population recovery under a simulated moratorium. Hence, the evolutionary legacy of size-selective harvesting includes populations that are productive under exploited conditions, but selectively disadvantaged to cope with natural selection pressures that often favor large body size. PMID:26136825

  9. Rate of language evolution is affected by population size

    PubMed Central

    Bromham, Lindell; Hua, Xia; Fitzpatrick, Thomas G.; Greenhill, Simon J.

    2015-01-01

    The effect of population size on patterns and rates of language evolution is controversial. Do languages with larger speaker populations change faster due to a greater capacity for innovation, or do smaller populations change faster due to more efficient diffusion of innovations? Do smaller populations suffer greater loss of language elements through founder effects or drift, or do languages with more speakers lose features due to a process of simplification? Revealing the influence of population size on the tempo and mode of language evolution not only will clarify underlying mechanisms of language change but also has practical implications for the way that language data are used to reconstruct the history of human cultures. Here, we provide, to our knowledge, the first empirical, statistically robust test of the influence of population size on rates of language evolution, controlling for the evolutionary history of the populations and formally comparing the fit of different models of language evolution. We compare rates of gain and loss of cognate words for basic vocabulary in Polynesian languages, an ideal test case with a well-defined history. We demonstrate that larger populations have higher rates of gain of new words whereas smaller populations have higher rates of word loss. These results show that demographic factors can influence rates of language evolution and that rates of gain and loss are affected differently. These findings are strikingly consistent with general predictions of evolutionary models. PMID:25646448

  10. Mapping the Misunderstood Population of Adult Students

    ERIC Educational Resources Information Center

    Ashburn, Elyse

    2007-01-01

    Adult students are not well documented, are frequently left out of discussions of higher-education policy, and are not fully understood by the colleges they attend, says a report ("Returning to Learning: Adults' Success in College is Key to America's Future") released this week by the Lumina Foundation for Education. As a result, those students…

  11. Drift by drift: effective population size is limited by advection

    PubMed Central

    2008-01-01

    Background Genetic estimates of effective population size often generate surprising results, including dramatically low ratios of effective population size to census size. This is particularly true for many marine species, and this effect has been associated with hypotheses of "sweepstakes" reproduction and selective hitchhiking. Results Here we show that in advective environments such as oceans and rivers, the mean asymmetric transport of passively dispersed reproductive propagules will act to limit the effective population size in species with a drifting developmental stage. As advection increases, effective population size becomes decoupled from census size as the persistence of novel genetic lineages is restricted to those that arise in a small upstream portion of the species domain. Conclusion This result leads to predictions about the maintenance of diversity in advective systems, and complements the "sweepstakes" hypothesis and other hypotheses proposed to explain cases of low allelic diversity in species with high fecundity. We describe the spatial extent of the species domain in which novel allelic diversity will be retained, thus determining how large an appropriately placed marine reserve must be to allow the persistence of endemic allelic diversity. PMID:18710549

  12. Population size and time since island isolation determine genetic diversity loss in insular frog populations.

    PubMed

    Wang, Supen; Zhu, Wei; Gao, Xu; Li, Xianping; Yan, Shaofei; Liu, Xuan; Yang, Ji; Gao, Zengxiang; Li, Yiming

    2014-02-01

    Understanding the factors that contribute to loss of genetic diversity in fragmented populations is crucial for conservation measurements. Land-bridge archipelagoes offer ideal model systems for identifying the long-term effects of these factors on genetic variations in wild populations. In this study, we used nine microsatellite markers to quantify genetic diversity and differentiation of 810 pond frogs (Pelophylax nigromaculatus) from 24 islands of the Zhoushan Archipelago and three sites on nearby mainland China and estimated the effects of the island area, population size, time since island isolation, distance to the mainland and distance to the nearest larger island on reduced genetic diversity of insular populations. The mainland populations displayed higher genetic diversity than insular populations. Genetic differentiations and no obvious gene flow were detected among the frog populations on the islands. Hierarchical partitioning analysis showed that only time since island isolation (square-root-transformed) and population size (log-transformed) significantly contributed to insular genetic diversity. These results suggest that decreased genetic diversity and genetic differentiations among insular populations may have been caused by random genetic drift following isolation by rising sea levels during the Holocene. The results provide strong evidence for a relationship between retained genetic diversity and population size and time since island isolation for pond frogs on the islands, consistent with the prediction of the neutral theory for finite populations. Our study highlights the importance of the size and estimated isolation time of populations in understanding the mechanisms of genetic diversity loss and differentiation in fragmented wild populations.

  13. The Population Size of the Lesser Bandicoot (Bandicota bengalensis) in Three Markets in Penang, Malaysia.

    PubMed

    Khairuddin, Nurul Liyana; Raghazli, Razlina; Sah, Shahrul Anuar Mohd; Shafie, Nur Juliani; Azman, Nur Munira

    2011-12-01

    A study of the population size of Bandicota bengalensis rats in three markets in Penang was conducted from April 2004 through May 2005. Taman Tun Sardon Market (TTS), Batu Lanchang Market (BTLG) and Bayan Lepas Market (BYNLP) were surveyed. Six sampling sessions were conducted in each market for four consecutive nights per session. The total captures of B. bengalensis in TTS, BTLG and BYNLP were 92%, 73% and 89% respectively. The total population of B. bengalensis in TTS was estimated as 265.4 (with a 95% confidence interval of 180.9-424.2). The total population at BTLG was estimated as 69.9 (with a 95% confidence interval of 35.5-148.9). At BYNLP, the total population was estimated as 134.7 (with a 95% confidence interval of 77.8-278.4). In general, adult male rats were captured most frequently at each site (55.19%), followed by adult females (31.69%), juvenile males (9.84%) and juvenile females (3.27%). The results showed that the number of rats captured at each site differed significantly according to sex ratio and maturity (χ(2) = 121.45, df = 3, p<0.01). Our results suggest that the population sizes found by the study may not represent the actual population size in each market owing to the low numbers of rats recaptured. This finding might have resulted from the variety of foods available in the markets.

  14. Population dynamic theory of size-dependent cannibalism.

    PubMed Central

    Claessen, David; de Roos, André M.; Persson, Lennart

    2004-01-01

    Cannibalism is characterized by four aspects: killing victims, gaining energy from victims, size-dependent interactions and intraspecific competition. In this review of mathematical models of cannibalistic populations, we relate the predicted population dynamic consequences of cannibalism to its four defining aspects. We distinguish five classes of effects of cannibalism: (i) regulation of population size; (ii) destabilization resulting in population cycles or chaos; (iii) stabilization by damping population cycles caused by other interactions; (iv) bistability such that, depending on the initial conditions, the population converges to one of two possible stable states; and (v) modification of the population size structure. The same effects of cannibalism may be caused by different combinations of aspects of cannibalism. By contrast, the same combination of aspects may lead to different effects. For particular cannibalistic species, the consequences of cannibalism will depend on the presence and details of the four defining aspects. Empirical evidence for the emerged theory of cannibalism is discussed briefly. The implications of the described dynamic effects of cannibalism are discussed in the context of community structure, making a comparison with the community effects of intraguild predation. PMID:15101690

  15. Geographical variations in adult body size and reproductive life history traits in an invasive anuran, Discoglossus pictus.

    PubMed

    Oromi, Neus; Pujol-Buxó, Eudald; San Sebastián, Olatz; Llorente, Gustavo A; Hammou, Mohamed Aït; Sanuy, Delfi

    2016-06-01

    Variability in life history traits positively affects the establishment and expansive potential of invasive species. In the present study, we analysed the variation of body size in seven populations - two native and five invasive - of the painted frog (Discoglossus pictus, Anura: Discoglossidae), native to North Africa and introduced in southern France and the north-east of the Iberian Peninsula. Other life history traits (age at maturity, size at maturity, longevity, median age and potential reproductive lifespan) were analysed in a native and an invasive population. We observed geographic variations in adult body size, related mainly to mean annual precipitation. Thus, populations had greater body size as mean annual precipitation increased, resulting in bigger specimens in the invasive populations. Adult body size and growth rates also varied between sexes in all studied populations, with males significantly larger than females. Age distribution varied between native (1-5 years) and invasive populations (2-4 years) and also between sexes. Our results suggest that higher precipitation promotes faster growth rates and larger adult body size that could facilitate the successful establishment of invasive populations.

  16. Colony size selection determines adult survival and dispersal preferences: allee effects in a colonial bird.

    PubMed

    Serrano, David; Oro, Daniel; Ursua, Esperanza; Tella, José L

    2005-08-01

    Avian coloniality traditionally has been investigated by examining how breeding success varies with colony size, but other crucial fitness components rarely have been examined. This may lead to wrong conclusions because unmeasured parameters may change the final fitness balance. We used multistate capture-recapture models to investigate adult survival and dispersal in relation to colony size within a long-term monitored population of lesser kestrels (Falco naumanni). Nest predation probability decreases with colony size, and adult survival is predicted to show the same trend because adults are exposed to the same suite of predators. As expected, survival probability was higher in large colonies (0.72+/-0.015; mean+/-SE) than in medium or small colonies (0.65+/-0.02). Additionally, dispersal probabilities were higher going from small to large colonies (0.20+/-0.01) than from large to small (0.08+/-0.01), as predicted by theory of habitat selection shaped by fitness maximization. These asymmetries are likely to generate size-specific colony population dynamics, so they should be taken into account in studies of colonial birds and other metapopulation-like systems. Allee effects, that is, positive density dependence, appear to be the cause of the evolution of dispersal behavior and may explain the maintenance of coloniality in this species. PMID:16032568

  17. Bayesian Optimization Algorithm, Population Sizing, and Time to Convergence

    SciTech Connect

    Pelikan, M.; Goldberg, D.E.; Cantu-Paz, E.

    2000-01-19

    This paper analyzes convergence properties of the Bayesian optimization algorithm (BOA). It settles the BOA into the framework of problem decomposition used frequently in order to model and understand the behavior of simple genetic algorithms. The growth of the population size and the number of generations until convergence with respect to the size of a problem is theoretically analyzed. The theoretical results are supported by a number of experiments.

  18. Cohort size and migration in a West Indian population.

    PubMed

    Brittain, A W

    1990-01-01

    The author examines the relationship between cohort size and migration patterns among the population of the French West Indies island of St. Barthelemy. Data show that "for people born from 1878 to 1967, neither cohort size nor fluctuations in external demands for labor had a lasting effect on the probability of eventual migration. Emigration rates only slowed after the development of the local tourist industry brought prosperity to the island." PMID:12283449

  19. RSV infection in the adult population.

    PubMed

    Ramirez, Julio A

    2008-11-01

    RSV is a significant and unrecognized cause of seasonal RTIs in adults, accounting for as much as 25 percent of excess wintertime mortality usually attributed to influenza. Nearly 80 percent of RSV-associated underlying respiratory and circulatory deaths occur among the elderly, and RSV is estimated to account for about 180,000 hospital admissions each year at a cost exceeding $1 billion. RSV also is recognized as an important cause of viral pneumonia in adults. Preventive measures, such as hand washing, are paramount, especially in hospitals and nursing homes where many immunocompromised patients reside. When RSV is circulating, it is advisable to minimize contact between high-risk patients and children.

  20. The elusive minimum viable population size for white sturgeon

    SciTech Connect

    Jager, Yetta; Lepla, Ken B.; Van Winkle, Webb; James, Mr Brad; McAdam, Dr Steve

    2010-01-01

    Biological conservation of sturgeon populations is a concern for many species. Those responsible for managing the white sturgeon (Acipenser transmontanus) and similar species are interested in identifying extinction thresholds to avoid. Two thresholds that exist in theory are the minimum viable population size (MVP) and minimum amount of suitable habitat. In this paper, we present both model and empirical estimates of these thresholds. We modified a population viability analysis (PVA) model for white sturgeon to include two new Allee mechanisms. Despite this, PVA-based MVP estimates were unrealistically low compared with empirical estimates unless opportunities for spawning were assumed to be less frequent. PVA results revealed a trade-off between MVP and habitat thresholds; smaller populations persisted in longer river segments and vice versa. Our empirical analyses suggested (1) a MVP range based on population trends from 1,194 to 27,700 individuals, and (2) a MVP estimate of 4,000 individuals based on recruitment. Long-term historical population surveys are needed for more populations to pinpoint an MVP based on trends, whereas the available data were sufficient to estimate MVP based on recruitment. Beyond the MVP, we developed a hierarchical model for population status based on empirical data. Metapopulation support was the most important predictor of population health, followed by the length of free-flowing habitat, with habitat thresholds at 26 and 150 km. Together, these results suggest that habitat and connectivity are important determinants of population status that likely influence the site-specific MVP thresholds.

  1. Litter Size Predicts Adult Stereotypic Behavior in Female Laboratory Mice

    PubMed Central

    Bechard, Allison; Nicholson, Anthony; Mason, Georgia

    2012-01-01

    Stereotypic behaviors are repetitive invariant behaviors that are common in many captive species and potentially indicate compromised welfare and suitability as research subjects. Adult laboratory mice commonly perform stereotypic bar-gnawing, route-tracing, and back-flipping, although great individual variation in frequency occurs. Early life factors (for example, level of maternal care received) have lasting effects on CNS functioning and abilities to cope with stress and therefore may also affect stereotypic behavior in offspring. Access to maternal resources and care are influenced by the number of pups in a litter; therefore, we examined both litter size and its potential correlate, weight at weaning, as early environmental predictors of adult stereotypic behavior in laboratory mice. Further, we assessed the effects on offspring stereotypic behavior of delaying the separation of mother and pups (weaning) beyond the standard 21 d of age. Analyzing stereotypic behavior in 3 different mouse colonies composed of 2 inbred strains (C57BL/6N and C57BL/6J) and an outbred stock (CD1[ICR]) revealed significant positive correlation between litter size and stereotypic behavior in female, but not male, mice. Weight and age at weaning did not significantly affect levels of stereotypy in either sex. Litter size therefore may be a useful indicator of individual predisposition to stereotypic behavior in female laboratory mice. PMID:23043805

  2. Recent divergences and size decreases of eastern gorilla populations.

    PubMed

    Roy, Justin; Arandjelovic, Mimi; Bradley, Brenda J; Guschanski, Katerina; Stephens, Colleen R; Bucknell, Dan; Cirhuza, Henry; Kusamba, Chifundera; Kyungu, Jean Claude; Smith, Vince; Robbins, Martha M; Vigilant, Linda

    2014-11-01

    Compared with other African apes, eastern gorillas (Gorilla beringei) have been little studied genetically. We used analysis of autosomal DNA genotypes obtained from non-invasively collected faecal samples to estimate the evolutionary histories of the two extant mountain gorilla populations and the closely related eastern lowland gorillas. Our results suggest that eastern lowland gorillas and mountain gorillas split beginning some 10 000 years ago, followed 5000 years ago by the split of the two mountain gorilla populations of Bwindi Impenetrable National Park and the Virungas Massif. All three populations have decreased in effective population size, with particularly substantial 10-fold decreases for the mountain gorillas. These dynamics probably reflect responses to habitat changes resulting from climate fluctuations over the past 20 000 years as well as increasing human influence in this densely populated region in the last several thousand years.

  3. Recent divergences and size decreases of eastern gorilla populations

    PubMed Central

    Roy, Justin; Arandjelovic, Mimi; Bradley, Brenda J.; Guschanski, Katerina; Stephens, Colleen R.; Bucknell, Dan; Cirhuza, Henry; Kusamba, Chifundera; Kyungu, Jean Claude; Smith, Vince; Robbins, Martha M.; Vigilant, Linda

    2014-01-01

    Compared with other African apes, eastern gorillas (Gorilla beringei) have been little studied genetically. We used analysis of autosomal DNA genotypes obtained from non-invasively collected faecal samples to estimate the evolutionary histories of the two extant mountain gorilla populations and the closely related eastern lowland gorillas. Our results suggest that eastern lowland gorillas and mountain gorillas split beginning some 10 000 years ago, followed 5000 years ago by the split of the two mountain gorilla populations of Bwindi Impenetrable National Park and the Virungas Massif. All three populations have decreased in effective population size, with particularly substantial 10-fold decreases for the mountain gorillas. These dynamics probably reflect responses to habitat changes resulting from climate fluctuations over the past 20 000 years as well as increasing human influence in this densely populated region in the last several thousand years. PMID:25376805

  4. Season of birth and population schizotypy: Results from a large sample of the adult general population.

    PubMed

    Konrath, Lisa; Beckius, Danièle; Tran, Ulrich S

    2016-08-30

    Although the last years have seen an increasing interest in schizotypy and its pathogenesis, there exist only a handful of studies examining the possible interaction between season of birth (SOB) and schizotypic personality structure. Available research used differing screening instruments, rendering comparisons between studies difficult, and sample sizes in adult populations may have been too small to detect a mild effect. The current study examined the association between SOB and psychometric schizotypy in the so far single-largest sample from the adult general population (N=8114), balanced for men and women, and utilizing a valid and reliable instrument for the assessment of schizotypy. Using the 12 most informative items of the Schizotypal Personality Questionnaire Brief, we obtained evidence of a small, but significant, effect of late winter and early spring births (February/March) on psychometric schizotypy. The effect was not constrained to women, but affected men and women alike. The observed association between SOB and schizotypy appears compatible with seasonal variations of temperature and influenza prevalence, and with recent evidence on seasonal variability in the activity of the human immune system. Our findings lend support to the continuum hypothesis of schizotypy and schizophrenia, for which SOB effects have been previously established. PMID:27310922

  5. Historical Analysis of Genetic Variation Reveals Low Effective Population Size in a Northern Pike (Esox Lucius) Population

    PubMed Central

    Miller, L. M.; Kapuscinski, A. R.

    1997-01-01

    Effective population size (N(e)) of a natural fish population was estimated from temporal changes in allele frequencies at seven microsatellite loci. Use of a historical collection of fish scales made it possible to increase the precision of estimates by increasing the time interval between samples and to use an equation developed for discrete generations without correcting for demographic parameters. Estimates of N(e) for the time intervals 1961-1977 and 1977-1993 were 35 and 72, respectively. For the entire interval, 1961-1993, the estimate of N(e) was 48 when based on a weighted mean derived from the above two estimates or 125 when calculated from 1961 and 1993 samples only. Corresponding ratios of effective size to adult census size ranged from 0.03 to 0.14. An N(e) of 48 over a 32-year period would imply that this population lost as much as 8% of its heterozygosity in that time. Results suggest the potential for using genetic methods based on microsatellite loci data to compare historical trends in N(e) with population dynamic parameters. Such comparisons will help to evaluate the relationship between genetic diversity and long-term persistence of natural populations. PMID:9383067

  6. Inferring the Dynamics of Effective Population Size Using Autosomal Genomes

    PubMed Central

    Hou, Zheng; Luo, Yin; Wang, Zhisheng; Zheng, Hong-Xiang; Wang, Yi; Zhou, Hang; Wu, Leqin; Jin, Li

    2016-01-01

    Next-generation sequencing technology has provided a great opportunity for inferring human demographic history by investigating changes in the effective population size (Ne). In this report, we introduce a strategy for estimating Ne dynamics, allowing the exploration of large multi-locus SNP datasets. We applied this strategy to the Phase 1 Han Chinese samples from the 1000 Genomes Project. The Han Chinese population has undergone a continuous expansion since 25,000 years ago, at first slowly from about 7,300 to 9,800 (at the end of the last glacial maximum about 15,000 YBP), then more quickly to about 46,000 (at the beginning of the Neolithic about 8,000 YBP), and then even more quickly to reach a population size of about 140,000 (recently). PMID:26832887

  7. Critical Mutation Rate Has an Exponential Dependence on Population Size in Haploid and Diploid Populations

    PubMed Central

    Aston, Elizabeth; Channon, Alastair; Day, Charles; Knight, Christopher G.

    2013-01-01

    Understanding the effect of population size on the key parameters of evolution is particularly important for populations nearing extinction. There are evolutionary pressures to evolve sequences that are both fit and robust. At high mutation rates, individuals with greater mutational robustness can outcompete those with higher fitness. This is survival-of-the-flattest, and has been observed in digital organisms, theoretically, in simulated RNA evolution, and in RNA viruses. We introduce an algorithmic method capable of determining the relationship between population size, the critical mutation rate at which individuals with greater robustness to mutation are favoured over individuals with greater fitness, and the error threshold. Verification for this method is provided against analytical models for the error threshold. We show that the critical mutation rate for increasing haploid population sizes can be approximated by an exponential function, with much lower mutation rates tolerated by small populations. This is in contrast to previous studies which identified that critical mutation rate was independent of population size. The algorithm is extended to diploid populations in a system modelled on the biological process of meiosis. The results confirm that the relationship remains exponential, but show that both the critical mutation rate and error threshold are lower for diploids, rather than higher as might have been expected. Analyzing the transition from critical mutation rate to error threshold provides an improved definition of critical mutation rate. Natural populations with their numbers in decline can be expected to lose genetic material in line with the exponential model, accelerating and potentially irreversibly advancing their decline, and this could potentially affect extinction, recovery and population management strategy. The effect of population size is particularly strong in small populations with 100 individuals or less; the exponential model has

  8. Size-specific sensitivity: Applying a new structured population model

    SciTech Connect

    Easterling, M.R.; Ellner, S.P.; Dixon, P.M.

    2000-03-01

    Matrix population models require the population to be divided into discrete stage classes. In many cases, especially when classes are defined by a continuous variable, such as length or mass, there are no natural breakpoints, and the division is artificial. The authors introduce the integral projection model, which eliminates the need for division into discrete classes, without requiring any additional biological assumptions. Like a traditional matrix model, the integral projection model provides estimates of the asymptotic growth rate, stable size distribution, reproductive values, and sensitivities of the growth rate to changes in vital rates. However, where the matrix model represents the size distributions, reproductive value, and sensitivities as step functions (constant within a stage class), the integral projection model yields smooth curves for each of these as a function of individual size. The authors describe a method for fitting the model to data, and they apply this method to data on an endangered plant species, northern monkshood (Aconitum noveboracense), with individuals classified by stem diameter. The matrix and integral models yield similar estimates of the asymptotic growth rate, but the reproductive values and sensitivities in the matrix model are sensitive to the choice of stage classes. The integral projection model avoids this problem and yields size-specific sensitivities that are not affected by stage duration. These general properties of the integral projection model will make it advantageous for other populations where there is no natural division of individuals into stage classes.

  9. Population size and time since island isolation determine genetic diversity loss in insular frog populations.

    PubMed

    Wang, Supen; Zhu, Wei; Gao, Xu; Li, Xianping; Yan, Shaofei; Liu, Xuan; Yang, Ji; Gao, Zengxiang; Li, Yiming

    2014-02-01

    Understanding the factors that contribute to loss of genetic diversity in fragmented populations is crucial for conservation measurements. Land-bridge archipelagoes offer ideal model systems for identifying the long-term effects of these factors on genetic variations in wild populations. In this study, we used nine microsatellite markers to quantify genetic diversity and differentiation of 810 pond frogs (Pelophylax nigromaculatus) from 24 islands of the Zhoushan Archipelago and three sites on nearby mainland China and estimated the effects of the island area, population size, time since island isolation, distance to the mainland and distance to the nearest larger island on reduced genetic diversity of insular populations. The mainland populations displayed higher genetic diversity than insular populations. Genetic differentiations and no obvious gene flow were detected among the frog populations on the islands. Hierarchical partitioning analysis showed that only time since island isolation (square-root-transformed) and population size (log-transformed) significantly contributed to insular genetic diversity. These results suggest that decreased genetic diversity and genetic differentiations among insular populations may have been caused by random genetic drift following isolation by rising sea levels during the Holocene. The results provide strong evidence for a relationship between retained genetic diversity and population size and time since island isolation for pond frogs on the islands, consistent with the prediction of the neutral theory for finite populations. Our study highlights the importance of the size and estimated isolation time of populations in understanding the mechanisms of genetic diversity loss and differentiation in fragmented wild populations. PMID:24351057

  10. Diabetes Mellitus and Its Correlates in an Iranian Adult Population

    PubMed Central

    Kamangar, Farin; Poutschi, Hossein; Islami, Farhad; Abnet, Christian C.; Freedman, Neal D.; Taylor, Philip R.; Pharoah, Paul; Boffetta, Paolo; Brennan, Paul J.; Dawsey, Sanford M.; Malekzadeh, Reza; Etemadi, Arash

    2011-01-01

    The rising epidemic of diabetes imposes a substantial economic burden on the Middle East. Using baseline data from a population based cohort study, we aimed to identify the correlates of diabetes mellitus (DM) in a mainly rural population from Iran. Between 2004 and 2007, 50044 adults between 30 and 87 years old from Golestan Province located in Northeast Iran were enrolled in the Golestan Cohort Study. Demographic and health-related information was collected using questionnaires. Individuals' body sizes at ages 15 and 30 were assessed by validated pictograms ranging from 1 (very lean) to 7 in men and 9 in women. DM diagnosis was based on the self-report of a physician's diagnosis. The accuracy of self-reported DM was evaluated in a subcohort of 3811 individuals using fasting plasma glucose level and medical records. Poisson regression with robust variance estimator was used to estimate prevalence ratios (PR's). The prevalence of self-reported DM standardized to the national and world population was 5.7% and 6.2%, respectively. Self-reported DM had 61.5% sensitivity and 97.6% specificity. Socioeconomic status was inversely associated with DM prevalence. Green tea and opium consumption increased the prevalence of DM. Obesity at all ages and extreme leanness in childhood increased diabetes prevalence. Being obese throughout life doubled DM prevalence in women (PR: 2.1; 95% CI: 1.8, 2.4). These findings emphasize the importance of improving DM awareness, improving general living conditions, and early lifestyle modifications in diabetes prevention. PMID:22053206

  11. Plant genotypic diversity increases population size of a herbivorous insect

    PubMed Central

    Utsumi, Shunsuke; Ando, Yoshino; Craig, Timothy P.; Ohgushi, Takayuki

    2011-01-01

    It is critical to incorporate the process of population dynamics into community genetics studies to identify the mechanisms of the linkage between host plant genetics and associated communities. We studied the effects of plant genotypic diversity of tall goldenrod Solidago altissima on the population dynamics of the aphid Uroleucon nigrotuberculatum. We found genotypic variation in plant resistance to the aphid in our experiments. To determine the impact of plant genotypic diversity on aphid population dynamics, we compared aphid densities under conditions of three treatments: single-genotype plots, mixed-genotype plots and mixed-genotype-with-cages plots. In the latter treatment plants were individually caged to prevent natural enemy attack and aphid movement among plants. The synergistic effects of genotypes on population size were demonstrated by the greater aphid population size in the mixed-genotype treatment than expected from additive effects alone. Two non-exclusive hypotheses are proposed to explain this pattern. First, there is a source–sink relationship among plant genotypes: aphids move from plant genotypes where their reproduction is high to genotypes where their reproduction is low. Second, natural enemy mortality is reduced in mixed plots in a matrix of diverse plant genotypes. PMID:21378084

  12. Comparing effective population sizes of dominant marine alphaproteobacteria lineages.

    PubMed

    Luo, Haiwei; Swan, Brandon K; Stepanauskas, Ramunas; Hughes, Austin L; Moran, Mary Ann

    2014-04-01

    A fundamental question in marine microbial ecology is how microbes adapt to ocean environments. Although numerically dominant populations are typically considered more successful, higher census population sizes (Nc) do not equate directly to a greater capability for adaptation. Instead, effective population size (Ne) determines the fate of deleterious and favourable mutations, and thus is a key parameter for determining the adaptive potential of a population. In the case of the SAR11 and Roseobacter lineages, two abundant heterotrophic bacteria in ocean surface waters with contrasting life history strategies, culture-independent population surveys suggest that SAR11s have greater Nc than Roseobacters. To determine relative Ne, we compared the ratio of nonsynonymous to synonymous substitution rates (ω) of recently diverged lineages of these taxa. Values of ω associated with several of the Roseobacter subclades were lower than for SAR11 subclades, suggesting greater Ne in these cases. Most Roseobacter lineages also had smaller ω values compared with an atypical basal Roseobacter lineage with a large Nc. This finding provides insight into variability in Ne across two important marine bacterial lineages, and provides an evolutionary context for considering how heterotrophic marine bacteria may differ in their ability to adapt to changing ocean habitats.

  13. Spatial Stability of Adult Aedes aegypti Populations

    PubMed Central

    Barrera, Roberto

    2011-01-01

    Vector control programs could be more efficient by identifying the location of highly productive sites of Aedes aegypti. This study explored if the number of female adults of Ae. aegypti in BG-Sentinel traps was clustered and if their spatial distribution changed in time in two neighborhoods in San Juan, Puerto Rico. Traps were uniformly distributed across each neighborhood (130 m from each other), and samples were taken every 3 weeks. Global and local spatial autocorrelations were explored. Spatial stability existed if the rank order of trap captures was kept in time. There was lack of global autocorrelation in both neighborhoods, precluding their stratification for control purposes. Hot and cold spots were identified, revealing the highly focal nature of Ae. aegypti. There was significant spatial stability throughout the study in both locations. The consistency in trap productivity in time could be used to increase the effectiveness of vector and dengue control programs. PMID:22144449

  14. Are heritability and selection related to population size in nature? Meta-analysis and conservation implications.

    PubMed

    Wood, Jacquelyn L A; Yates, Matthew C; Fraser, Dylan J

    2016-06-01

    It is widely thought that small populations should have less additive genetic variance and respond less efficiently to natural selection than large populations. Across taxa, we meta-analytically quantified the relationship between adult census population size (N) and additive genetic variance (proxy: h (2)) and found no reduction in h (2) with decreasing N; surveyed populations ranged from four to one million individuals (1735 h (2) estimates, 146 populations, 83 species). In terms of adaptation, ecological conditions may systematically differ between populations of varying N; the magnitude of selection these populations experience may therefore also differ. We thus also meta-analytically tested whether selection changes with N and found little evidence for systematic differences in the strength, direction or form of selection with N across different trait types and taxa (7344 selection estimates, 172 populations, 80 species). Collectively, our results (i) indirectly suggest that genetic drift neither overwhelms selection more in small than in large natural populations, nor weakens adaptive potential/h (2) in small populations, and (ii) imply that natural populations of varying sizes experience a variety of environmental conditions, without consistently differing habitat quality at small N. However, we caution that the data are currently insufficient to determine whether some small populations may retain adaptive potential definitively. Further study is required into (i) selection and genetic variation in completely isolated populations of known N, under-represented taxonomic groups, and nongeneralist species, (ii) adaptive potential using multidimensional approaches and (iii) the nature of selective pressures for specific traits. PMID:27247616

  15. Ochre star mortality during the 2014 wasting disease epizootic: role of population size structure and temperature.

    PubMed

    Eisenlord, Morgan E; Groner, Maya L; Yoshioka, Reyn M; Elliott, Joel; Maynard, Jeffrey; Fradkin, Steven; Turner, Margaret; Pyne, Katie; Rivlin, Natalie; van Hooidonk, Ruben; Harvell, C Drew

    2016-03-01

    Over 20 species of asteroids were devastated by a sea star wasting disease (SSWD) epizootic, linked to a densovirus, from Mexico to Alaska in 2013 and 2014. For Pisaster ochraceus from the San Juan Islands, South Puget Sound and Washington outer coast, time-series monitoring showed rapid disease spread, high mortality rates in 2014, and continuing levels of wasting in the survivors in 2015. Peak prevalence of disease at 16 sites ranged to 100%, with an overall mean of 61%. Analysis of longitudinal data showed disease risk was correlated with both size and temperature and resulted in shifts in population size structure; adult populations fell to one quarter of pre-outbreak abundances. In laboratory experiments, time between development of disease signs and death was influenced by temperature in adults but not juveniles and adult mortality was 18% higher in the 19 °C treatment compared to the lower temperature treatments. While larger ochre stars developed disease signs sooner than juveniles, diseased juveniles died more quickly than diseased adults. Unusual 2-3 °C warm temperature anomalies were coincident with the summer 2014 mortalities. We suggest these warm waters could have increased the disease progression and mortality rates of SSWD in Washington State. PMID:26880844

  16. Ochre star mortality during the 2014 wasting disease epizootic: role of population size structure and temperature

    PubMed Central

    Eisenlord, Morgan E.; Yoshioka, Reyn M.; Elliott, Joel; Maynard, Jeffrey; Fradkin, Steven; Turner, Margaret; Pyne, Katie; Rivlin, Natalie; van Hooidonk, Ruben; Harvell, C. Drew

    2016-01-01

    Over 20 species of asteroids were devastated by a sea star wasting disease (SSWD) epizootic, linked to a densovirus, from Mexico to Alaska in 2013 and 2014. For Pisaster ochraceus from the San Juan Islands, South Puget Sound and Washington outer coast, time-series monitoring showed rapid disease spread, high mortality rates in 2014, and continuing levels of wasting in the survivors in 2015. Peak prevalence of disease at 16 sites ranged to 100%, with an overall mean of 61%. Analysis of longitudinal data showed disease risk was correlated with both size and temperature and resulted in shifts in population size structure; adult populations fell to one quarter of pre-outbreak abundances. In laboratory experiments, time between development of disease signs and death was influenced by temperature in adults but not juveniles and adult mortality was 18% higher in the 19°C treatment compared to the lower temperature treatments. While larger ochre stars developed disease signs sooner than juveniles, diseased juveniles died more quickly than diseased adults. Unusual 2–3°C warm temperature anomalies were coincident with the summer 2014 mortalities. We suggest these warm waters could have increased the disease progression and mortality rates of SSWD in Washington State. PMID:26880844

  17. Association of Overweight with Food Portion Size among Adults of São Paulo – Brazil

    PubMed Central

    Mendes, Aline; Crispim, Sandra Patricia; Marchioni, Dirce Maria; Fisberg, Regina Mara

    2016-01-01

    Background Although studies show that portion size affects energy intake, few have demonstrated a link between portion size and weight status, especially in free-living populations. The objective of the present study was to assess the relationship between food portion sizes and overweight in a representative population of adults of São Paulo, Brazil. Methods Cross-sectional population-based study with 1005 adults from São Paulo, Brazil. Dietary data were obtained from two 24-hour recalls. Reported foods were classified into groups and energy contribution, prevalence of consumers and portion sizes were calculated. Individuals were classified according to BMI in with and without overweight. Logistic regression models were used to evaluate the association between food portion sizes and being overweight. Results The most consumed food groups were: beans, breads/rolls, coffee/tea, milk, rice, and sugar. Rice, red meat, breads/rolls, and white meat were the groups with the highest percentage of contribution to total energy intake. Butter/margarine, toasts/biscuits, sugar, and cakes were the groups with the highest energy density. After adjustment for confounding variables, overweight was associated with larger portions of pizza (OR = 1.052; p = 0.048), red meat (OR = 1.025; p = 0.043), rice (OR = 1.033; p<0.001), salted snacks (OR = 1.078; p = 0.022), and soft drinks (OR = 1.016; p = 0.007). Conclusions Larger portions of few food groups with different energy densities were associated with being overweight, suggesting that overweight may be related to the consumption of larger portion sizes of a series of food groups, not a food group alone. Additionally, we highlight the importance of considering underreporting as a confounding factor in these associations. PMID:27706222

  18. Effects of body size and temperature on population growth.

    PubMed

    Savage, Van M; Gilloly, James F; Brown, James H; Charnov, Eric L

    2004-03-01

    For at least 200 years, since the time of Malthus, population growth has been recognized as providing a critical link between the performance of individual organisms and the ecology and evolution of species. We present a theory that shows how the intrinsic rate of exponential population growth, rmax, and the carrying capacity, K, depend on individual metabolic rate and resource supply rate. To do this, we construct equations for the metabolic rates of entire populations by summing over individuals, and then we combine these population-level equations with Malthusian growth. Thus, the theory makes explicit the relationship between rates of resource supply in the environment and rates of production of new biomass and individuals. These individual-level and population-level processes are inextricably linked because metabolism sets both the demand for environmental resources and the resource allocation to survival, growth, and reproduction. We use the theory to make explicit how and why rmax exhibits its characteristic dependence on body size and temperature. Data for aerobic eukaryotes, including algae, protists, insects, zooplankton, fishes, and mammals, support these predicted scalings for rmax. The metabolic flux of energy and materials also dictates that the carrying capacity or equilibrium density of populations should decrease with increasing body size and increasing temperature. Finally, we argue that body mass and body temperature, through their effects on metabolic rate, can explain most of the variation in fecundity and mortality rates. Data for marine fishes in the field support these predictions for instantaneous rates of mortality. This theory links the rates of metabolism and resource use of individuals to life-history attributes and population dynamics for a broad assortment of organisms, from unicellular organisms to mammals.

  19. Minimum viable population sizes and global extinction risk are unrelated.

    PubMed

    Brook, Barry W; Traill, Lochran W; Bradshaw, Corey J A

    2006-04-01

    Theoretical and empirical work has shown that once reduced in size and geographical range, species face a considerably elevated risk of extinction. We predict minimum viable population sizes (MVP) for 1198 species based on long-term time-series data and model-averaged population dynamics simulations. The median MVP estimate was 1377 individuals (90% probability of persistence over 100 years) but the overall distribution was wide and strongly positively skewed. Factors commonly cited as correlating with extinction risk failed to predict MVP but were able to predict successfully the probability of World Conservation Union Listing. MVPs were most strongly related to local environmental variation rather than a species' intrinsic ecological and life history attributes. Further, the large variation in MVP across species is unrelated to (or at least dwarfed by) the anthropogenic threats that drive the global biodiversity crisis by causing once-abundant species to decline.

  20. Estimating Population Size Using the Network Scale Up Method

    PubMed Central

    Maltiel, Rachael; Raftery, Adrian E.; McCormick, Tyler H.; Baraff, Aaron J.

    2015-01-01

    We develop methods for estimating the size of hard-to-reach populations from data collected using network-based questions on standard surveys. Such data arise by asking respondents how many people they know in a specific group (e.g. people named Michael, intravenous drug users). The Network Scale up Method (NSUM) is a tool for producing population size estimates using these indirect measures of respondents’ networks. Killworth et al. (1998a,b) proposed maximum likelihood estimators of population size for a fixed effects model in which respondents’ degrees or personal network sizes are treated as fixed. We extend this by treating personal network sizes as random effects, yielding principled statements of uncertainty. This allows us to generalize the model to account for variation in people’s propensity to know people in particular subgroups (barrier effects), such as their tendency to know people like themselves, as well as their lack of awareness of or reluctance to acknowledge their contacts’ group memberships (transmission bias). NSUM estimates also suffer from recall bias, in which respondents tend to underestimate the number of members of larger groups that they know, and conversely for smaller groups. We propose a data-driven adjustment method to deal with this. Our methods perform well in simulation studies, generating improved estimates and calibrated uncertainty intervals, as well as in back estimates of real sample data. We apply them to data from a study of HIV/AIDS prevalence in Curitiba, Brazil. Our results show that when transmission bias is present, external information about its likely extent can greatly improve the estimates. The methods are implemented in the NSUM R package. PMID:26949438

  1. Measles, mumps, rubella and chickenpox in the adult population.

    PubMed

    Boodley, C A; Jaquis, J L

    1989-02-01

    The common "childhood diseases" of measles, mumps, rubella and chickenpox do appear in the adult population. It is important for health care practitioners to recognize these diseases in adults and be alert for possible complications which may be more serious than those found in children. This article discusses epidemiology, transmission, signs and symptoms, treatment, possible complications, confirmatory tests and immunization recommendations for each of the four diseases.

  2. The effect of neighborhood size on effective population size in theory and in practice.

    PubMed

    Nunney, L

    2016-10-01

    The distinction between the effective size of a population (Ne) and the effective size of its neighborhoods (Nn) has sometimes become blurred. Ne reflects the effect of random sampling on the genetic composition of a population of size N, whereas Nn is a measure of within-population spatial genetic structure and depends strongly on the dispersal characteristics of a species. Although Nn is independent of Ne, the reverse is not true. Using simulations of a population of annual plants, it was found that the effect of Nn on Ne was well approximated by Ne=N/(1-FIS), where FIS (determined by Nn) was evaluated population wide. Nn only had a notable influence of increasing Ne as it became smaller (⩽16). In contrast, the effect of Nn on genetic estimates of Ne was substantial. Using the temporal method (a standard two-sample approach) based on 1000 single-nucleotide polymorphisms (SNPs), and varying sampling method, sample size (2-25% of N) and interval between samples (T=1-32 generations), estimates of Ne ranged from infinity to <0.1% of the true value (defined as Ne based on 100% sampling). Estimates were never accurate unless Nn and T were large. Three sampling techniques were tested: same-site resampling, different-site resampling and random sampling. Random sampling was the least biased method. Extremely low estimates often resulted when different-site resampling was used, especially when the population was large and the sample fraction was small, raising the possibility that this estimation bias could be a factor determining some very low Ne/N that have been published. PMID:27553453

  3. Determining population size of territorial red-winged blackbirds

    USGS Publications Warehouse

    Albers, P.H.

    1976-01-01

    Population sizes of territorial male red-winged blackbirds (Agelaius phoeniceus) were determined with counts of territorial males (area count) and a Petersen-Lincoln Index method for roadsides (roadside estimate). Weather conditions and time of day did not influence either method. Combined roadside estimates had smaller error bounds than the individual transect estimates and were not hindered by the problem of zero recaptures. Roadside estimates were usually one-half as large as the area counts, presumably due to an observer bias for marked birds. The roadside estimate provides only an index of major changes in populations of territorial male redwings. When the roadside estimate is employed, the area count should be used to determine the amount and nature of observer bias. For small population surveys, the area count is probably more reliable and accurate than the roadside estimate.

  4. The Design of a Mobile Portion Size Estimation Interface for a Low Literacy Population

    PubMed Central

    Chaudry, Beenish; Connelly, Kay; Siek, Katie A.; Welch, Janet L.

    2011-01-01

    Being aware of one’s portion sizes is a key component of maintaining a healthy diet, however, it is difficult for individuals especially low literacy populations to estimate their consumption. Nutritional monitoring applications can help but most of them are designed for people with high literacy and numeracy skills. In this paper, we designed and evaluated six portion size estimation interfaces through a Wizard of Oz based experiment using low-fidelity prototypes with ten varying literacy individuals. The interfaces were designed based on the cognitive strategies adults use for reporting portion sizes in diet recall studies. Participants made correct estimates with interfaces designed for liquid and amorphous foods, but had difficulties with those designed for solid foods. Based on these findings, we provide recommendations for designing accurate and low literacy-accessible portion size estimating mobile interfaces. PMID:22914603

  5. A Re-Evaluation of the Size of the White Shark (Carcharodon carcharias) Population off California, USA

    PubMed Central

    Burgess, George H.; Bruce, Barry D.; Cailliet, Gregor M.; Goldman, Kenneth J.; Grubbs, R. Dean; Lowe, Christopher G.; MacNeil, M. Aaron; Mollet, Henry F.; Weng, Kevin C.; O'Sullivan, John B.

    2014-01-01

    White sharks are highly migratory and segregate by sex, age and size. Unlike marine mammals, they neither surface to breathe nor frequent haul-out sites, hindering generation of abundance data required to estimate population size. A recent tag-recapture study used photographic identifications of white sharks at two aggregation sites to estimate abundance in “central California” at 219 mature and sub-adult individuals. They concluded this represented approximately one-half of the total abundance of mature and sub-adult sharks in the entire eastern North Pacific Ocean (ENP). This low estimate generated great concern within the conservation community, prompting petitions for governmental endangered species designations. We critically examine that study and find violations of model assumptions that, when considered in total, lead to population underestimates. We also use a Bayesian mixture model to demonstrate that the inclusion of transient sharks, characteristic of white shark aggregation sites, would substantially increase abundance estimates for the adults and sub-adults in the surveyed sub-population. Using a dataset obtained from the same sampling locations and widely accepted demographic methodology, our analysis indicates a minimum all-life stages population size of >2000 individuals in the California subpopulation is required to account for the number and size range of individual sharks observed at the two sampled sites. Even accounting for methodological and conceptual biases, an extrapolation of these data to estimate the white shark population size throughout the ENP is inappropriate. The true ENP white shark population size is likely several-fold greater as both our study and the original published estimate exclude non-aggregating sharks and those that independently aggregate at other important ENP sites. Accurately estimating the central California and ENP white shark population size requires methodologies that account for biases introduced by

  6. A re-evaluation of the size of the white shark (Carcharodon carcharias) population off California, USA.

    PubMed

    Burgess, George H; Bruce, Barry D; Cailliet, Gregor M; Goldman, Kenneth J; Grubbs, R Dean; Lowe, Christopher G; MacNeil, M Aaron; Mollet, Henry F; Weng, Kevin C; O'Sullivan, John B

    2014-01-01

    White sharks are highly migratory and segregate by sex, age and size. Unlike marine mammals, they neither surface to breathe nor frequent haul-out sites, hindering generation of abundance data required to estimate population size. A recent tag-recapture study used photographic identifications of white sharks at two aggregation sites to estimate abundance in "central California" at 219 mature and sub-adult individuals. They concluded this represented approximately one-half of the total abundance of mature and sub-adult sharks in the entire eastern North Pacific Ocean (ENP). This low estimate generated great concern within the conservation community, prompting petitions for governmental endangered species designations. We critically examine that study and find violations of model assumptions that, when considered in total, lead to population underestimates. We also use a Bayesian mixture model to demonstrate that the inclusion of transient sharks, characteristic of white shark aggregation sites, would substantially increase abundance estimates for the adults and sub-adults in the surveyed sub-population. Using a dataset obtained from the same sampling locations and widely accepted demographic methodology, our analysis indicates a minimum all-life stages population size of >2000 individuals in the California subpopulation is required to account for the number and size range of individual sharks observed at the two sampled sites. Even accounting for methodological and conceptual biases, an extrapolation of these data to estimate the white shark population size throughout the ENP is inappropriate. The true ENP white shark population size is likely several-fold greater as both our study and the original published estimate exclude non-aggregating sharks and those that independently aggregate at other important ENP sites. Accurately estimating the central California and ENP white shark population size requires methodologies that account for biases introduced by sampling a

  7. A re-evaluation of the size of the white shark (Carcharodon carcharias) population off California, USA.

    PubMed

    Burgess, George H; Bruce, Barry D; Cailliet, Gregor M; Goldman, Kenneth J; Grubbs, R Dean; Lowe, Christopher G; MacNeil, M Aaron; Mollet, Henry F; Weng, Kevin C; O'Sullivan, John B

    2014-01-01

    White sharks are highly migratory and segregate by sex, age and size. Unlike marine mammals, they neither surface to breathe nor frequent haul-out sites, hindering generation of abundance data required to estimate population size. A recent tag-recapture study used photographic identifications of white sharks at two aggregation sites to estimate abundance in "central California" at 219 mature and sub-adult individuals. They concluded this represented approximately one-half of the total abundance of mature and sub-adult sharks in the entire eastern North Pacific Ocean (ENP). This low estimate generated great concern within the conservation community, prompting petitions for governmental endangered species designations. We critically examine that study and find violations of model assumptions that, when considered in total, lead to population underestimates. We also use a Bayesian mixture model to demonstrate that the inclusion of transient sharks, characteristic of white shark aggregation sites, would substantially increase abundance estimates for the adults and sub-adults in the surveyed sub-population. Using a dataset obtained from the same sampling locations and widely accepted demographic methodology, our analysis indicates a minimum all-life stages population size of >2000 individuals in the California subpopulation is required to account for the number and size range of individual sharks observed at the two sampled sites. Even accounting for methodological and conceptual biases, an extrapolation of these data to estimate the white shark population size throughout the ENP is inappropriate. The true ENP white shark population size is likely several-fold greater as both our study and the original published estimate exclude non-aggregating sharks and those that independently aggregate at other important ENP sites. Accurately estimating the central California and ENP white shark population size requires methodologies that account for biases introduced by sampling a

  8. Population Size Estimation of Men Who Have Sex with Men in Tbilisi, Georgia; Multiple Methods and Triangulation of Findings

    PubMed Central

    Sulaberidze, Lela; Mirzazadeh, Ali; Chikovani, Ivdity; Shengelia, Natia; Tsereteli, Nino; Gotsadze, George

    2016-01-01

    Introduction An accurate estimation of the population size of men who have sex with men (MSM) is critical to the success of HIV program planning and to monitoring of the response to epidemic as a whole, but is quite often missing. In this study, our aim was to estimate the population size of MSM in Tbilisi, Georgia and compare it with other estimates in the region. Methods In the absence of a gold standard for estimating the population size of MSM, this study reports a range of methods, including network scale-up, mobile/web apps multiplier, service and unique object multiplier, network-based capture-recapture, Handcock RDS-based and Wisdom of Crowds methods. To apply all these methods, two surveys were conducted: first, a household survey among 1,015 adults from the general population, and second, a respondent driven sample of 210 MSM. We also conducted a literature review of MSM size estimation in Eastern European and Central Asian countries. Results The median population size of MSM generated from all previously mentioned methods was estimated to be 5,100 (95% Confidence Interval (CI): 3,243 ~ 9,088). This corresponds to 1.42% (95%CI: 0.9% ~ 2.53%) of the adult male population in Tbilisi. Conclusion Our size estimates of the MSM population (1.42% (95%CI: 0.9% ~ 2.53%) of the adult male population in Tbilisi) fall within ranges reported in other Eastern European and Central Asian countries. These estimates can provide valuable information for country level HIV prevention program planning and evaluation. Furthermore, we believe, that our results will narrow the gap in data availability on the estimates of the population size of MSM in the region. PMID:26828366

  9. Naturalization of plant populations: the role of cultivation and population size and density.

    PubMed

    Minton, Mark S; Mack, Richard N

    2010-10-01

    Field experimentation is required to assess the effects of environmental stochasticity on small immigrant plant populations-a widely understood but largely unexplored aspect of predicting any species' likelihood of naturalization and potential invasion. Cultivation can mitigate this stochasticity, although the outcome for a population under cultivation nevertheless varies enormously from extinction to persistence. Using factorial experiments, we investigated the effects of population size, density, and cultivation (irrigation) on the fate of founder populations for four alien species with different life history characteristics (Echinochloa frumentacea, Fagopyrum esculentum, Helianthus annuus, and Trifolium incarnatum) in eastern Washington, USA. The fate of founder populations was highly variable within and among the 3 years of experimentation and illustrates the often precarious environment encountered by plant immigrants. Larger founder populations produced more seeds (P < 0.001); the role of founder population size, however, differed among years. Irrigation resulted in higher percent survival (P < 0.001) and correspondingly larger net reproductive rate (R(0); P < 0.001). But the minimum level of irrigation for establishment, R(0) > 1, differed among years and species. Sowing density did not affect the likelihood of establishment for any species. Our results underscore the importance of environmental stochasticity in determining the fate of founder populations and the potential of cultivation and large population size in countering the long odds against naturalization. Any implementation of often proposed post-immigration field trials to assess the risk of an alien species becoming naturalized, a requisite step toward invasion, will need to assess different sizes of founder populations and the extent and character of cultivation (intentional or unintentional) that the immigrants might receive.

  10. Description and validation of a method for simultaneous estimation of effective population size and mutation rate from human population data.

    PubMed Central

    Chakraborty, R; Neel, J V

    1989-01-01

    A method is presented for utilizing population data on electrophoretic variants of proteins to estimate simultaneously the effective sizes (Ne values) of the populations in question and the rate of mutation resulting in electromorphs at the loci whose products were surveyed. The method is applied to data from 12 relatively unacculturated Amerindian tribes for whom census data and independent estimates of the number of different electrophoretic variants at 27 loci are available. Because of tribal demographic structure, Ne should be less than the current number of reproductive-aged adults. In fact, it is substantially greater for 7 tribes, most likely due to intertribal migration and a recent decrease in tribal size. Estimates of locus mutation rates for the 27 loci vary by more than a factor of 20, with an average of 1.1 x 10(-5) per locus per generation. This latter estimate is in satisfactory agreement with the results of other indirect approaches to the estimation of mutation rates in these tribes but about two times higher than the results of direct estimates based on these same loci in studies on civilized populations. This discrepancy could be due to the above-hypothesized migration and to decreases in tribal size. PMID:2594777

  11. Making sense of genetic estimates of effective population size.

    PubMed

    Waples, Robin S

    2016-10-01

    The last decade has seen an explosion of interest in use of genetic markers to estimate effective population size, Ne . Effective population size is important both theoretically (Ne is a key parameter in almost every aspect of evolutionary biology) and for practical application (Ne determines rates of genetic drift and loss of genetic variability and modulates the effectiveness of selection, so it is crucial to consider in conservation). As documented by Palstra & Fraser (), most of the recent growth in Ne estimation can be attributed to development or refinement of methods that can use a single sample of individuals (the older temporal method requires at least two samples separated in time). As with other population genetic methods, performance of new Ne estimators is typically evaluated with simulated data for a few scenarios selected by the author(s). Inevitably, these initial evaluations fail to fully consider the consequences of violating simplifying assumptions, such as discrete generations, closed populations of constant size and selective neutrality. Subsequently, many researchers studying natural or captive populations have reported estimates of Ne for multiple methods; often these estimates are congruent, but that is not always the case. Because true Ne is rarely known in these empirical studies, it is difficult to make sense of the results when estimates differ substantially among methods. What is needed is a rigorous, comparative analysis under realistic scenarios for which true Ne is known. Recently, Gilbert & Whitlock () did just that for both single-sample and temporal methods under a wide range of migration schemes. In the current issue of Molecular Ecology, Wang () uses simulations to evaluate performance of four single-sample Ne estimators. In addition to assessing effects of true Ne , sample size, and number of loci, Wang also evaluated performance under changing abundance, physical linkage and genotyping errors, as well as for some alternative

  12. Hamstring graft size and anthropometry in south Indian population

    PubMed Central

    Challa, Supradeeptha; Satyaprasad, Jonnalagedda

    2013-01-01

    Background and Aim The role of anthropometric measurements in the prediction of hamstring autograft size in Indian population remains unclear. Till now, no studies have been done on Indian population. Methods We evaluated 41 consecutive patients (34 males, 7 females) prospectively with anterior cruciate ligament deficiency scheduled for reconstruction using hamstring autograft at our institution between June 2011 and June 2013. Preoperatively we recorded age, gender, height, weight, body mass index, and activity level. Intraoperative measurements of semitendinosus tendon like absolute length, diameter before fashioning the graft and final diameter of the tripled graft using sizing tubes calibrated to 1 mm. Correlation coefficient (Pearson's r) analysis was used. Results As per study there is no correlation between graft diameter, age, sex, weight, activity, and body mass index, of patients. Height of patients correlated to graft diameter in both Indian men and women (p < 0.001). Conclusion Anthropometric measurements such as weight, gender, activity level cannot be used as definitive predictors for the hamstring graft diameter during harvest but height of the patients can be taken as good predictor in Indian population. PMID:26403553

  13. Estimated Full Scale IQ in an Adult Heroin Addict Population.

    ERIC Educational Resources Information Center

    Chastain, Robert L.; And Others

    The research concerning intellectual functioning in addict populations has not addressed basic questions concerning why and how intelligence quotients (IQ) might be related to drug addiction. A study was undertaken to estimate intellectual functioning based upon a demographic profile for Wechsler Adult Intelligence Scale-Revised (WAIS-R) Full…

  14. Estimation of effective population size in continuously distributed populations: there goes the neighborhood

    PubMed Central

    Neel, M C; McKelvey, K; Ryman, N; Lloyd, M W; Short Bull, R; Allendorf, F W; Schwartz, M K; Waples, R S

    2013-01-01

    Use of genetic methods to estimate effective population size (Ne) is rapidly increasing, but all approaches make simplifying assumptions unlikely to be met in real populations. In particular, all assume a single, unstructured population, and none has been evaluated for use with continuously distributed species. We simulated continuous populations with local mating structure, as envisioned by Wright's concept of neighborhood size (NS), and evaluated performance of a single-sample estimator based on linkage disequilibrium (LD), which provides an estimate of the effective number of parents that produced the sample (Nb). Results illustrate the interacting effects of two phenomena, drift and mixture, that contribute to LD. Samples from areas equal to or smaller than a breeding window produced estimates close to the NS. As the sampling window increased in size to encompass multiple genetic neighborhoods, mixture LD from a two-locus Wahlund effect overwhelmed the reduction in drift LD from incorporating offspring from more parents. As a consequence, never approached the global Ne, even when the geographic scale of sampling was large. Results indicate that caution is needed in applying standard methods for estimating effective size to continuously distributed populations. PMID:23652561

  15. Understanding the size growth of massive galaxies through stellar populations

    NASA Astrophysics Data System (ADS)

    Ferreras, Ignacio

    2015-08-01

    The growth of massive galaxies remains an open problem. The observational evidence seems to converge on a two-stage scenario, where a compact massive core is formed during an early, intense burst, followed by a more extended process of mass and size growth at intermediate redshift (z<2). This talk focuses on the latter, exploring the growth of massive galaxies through a detailed analysis of the stellar populations in close pairs, to study their formation history. Two surveys are explored (SHARDS and GAMA), probing the stellar populations of pre-merging systems out to z~1.3, and down to a mass ratio ~1:100. We will compare the results between medium band spectral fitting (SHARDS) and those from a more targeted analysis of line strengths in the GAMA data. The combination of the two datasets provide a unique insight of the growth channel of massive galaxies via mergers.

  16. Population size does not explain past changes in cultural complexity

    PubMed Central

    Vaesen, Krist; Collard, Mark; Cosgrove, Richard; Roebroeks, Wil

    2016-01-01

    Demography is increasingly being invoked to account for features of the archaeological record, such as the technological conservatism of the Lower and Middle Pleistocene, the Middle to Upper Paleolithic transition, and cultural loss in Holocene Tasmania. Such explanations are commonly justified in relation to population dynamic models developed by Henrich [Henrich J (2004) Am Antiq 69:197–214] and Powell et al. [Powell A, et al. (2009) Science 324(5932):1298–1301], which appear to demonstrate that population size is the crucial determinant of cultural complexity. Here, we show that these models fail in two important respects. First, they only support a relationship between demography and culture in implausible conditions. Second, their predictions conflict with the available archaeological and ethnographic evidence. We conclude that new theoretical and empirical research is required to identify the factors that drove the changes in cultural complexity that are documented by the archaeological record. PMID:27044082

  17. Asymmetric competition causes multimodal size distributions in spatially structured populations.

    PubMed

    Velázquez, Jorge; Allen, Robert B; Coomes, David A; Eichhorn, Markus P

    2016-01-27

    Plant sizes within populations often exhibit multimodal distributions, even when all individuals are the same age and have experienced identical conditions. To establish the causes of this, we created an individual-based model simulating the growth of trees in a spatially explicit framework, which was parametrized using data from a long-term study of forest stands in New Zealand. First, we demonstrate that asymmetric resource competition is a necessary condition for the formation of multimodal size distributions within cohorts. By contrast, the legacy of small-scale clustering during recruitment is transient and quickly overwhelmed by density-dependent mortality. Complex multi-layered size distributions are generated when established individuals are restricted in the spatial domain within which they can capture resources. The number of modes reveals the effective number of direct competitors, while the separation and spread of modes are influenced by distances among established individuals. Asymmetric competition within local neighbourhoods can therefore generate a range of complex size distributions within even-aged cohorts.

  18. Genotypic structure of a Drosophila population for adult locomotor activity

    SciTech Connect

    Grechanyi, G.V.; Korzun, V.M.

    1995-01-01

    Analysis of the variation of adult locomotor activity in four samples taken at different times from a natural population of Drosophila melanogaster showed that the total variation of this trait is relatively stable in time and has a substantial genetic component. Genotypic structure of the population for locomotor activity is characterized by the presence of large groups of genotypes with high and low values of this trait. A possible explanation for the presence of such groups in a population is cyclic density-dependent selection.

  19. Estimating the number of sex workers in South Africa: rapid population size estimation.

    PubMed

    Konstant, Tracey L; Rangasami, Jerushah; Stacey, Maria J; Stewart, Michelle L; Nogoduka, Coceka

    2015-02-01

    Although recognized as a vulnerable population, there is no national population size estimate for sex workers in South Africa. A rapid sex worker enumeration exercise was undertaken in twelve locations across the country based on principles of participatory mapping and Wisdom of the Crowd. Sites with a range of characteristics were selected, focusing on level of urbanisation, trucking, mining and borders. At each site, sex worker focus groups mapped local hotspots. Interviews with sex workers at identified hotspots were used to estimate the numbers and genders of sex workers working in each. Estimates provided in the literature were combined with enumeration exercise results to define assumptions that could be applied to a national extrapolation. A working estimate was reached of between 131,000 and 182,000 sex worker in South Africa, or between 0.76 and 1 % of the adult female population. The success of the exercise depended on integral involvement of sex worker peer educators and strong ethical considerations.

  20. Increasing body size among adult cook islanders between 1966 and 1996.

    PubMed

    Ulijaszek, S J

    2001-01-01

    There is limited evidence of a secular trend toward increased body size among populations in the Pacific Region, although some populations have shown a clear rise in overweight and obesity across the past 30 years or so. Mean height, weight and body mass index (BMI) of adults surveyed in 1996 on Rarotonga, the Cook Islands, are reported by age group and compared with data collected in 1966 by Evans and Prior, to determine the extent to which a secular trend in increasing body size has taken place across this 30-year period. In addition, a comparison of these anthropometric variables between subjects born on the most modernized island of Rarotonga with those born on other less-modernized islands is made, to determine the extent to which adult body size differs according to place of origin. Comparing the sample of those born on Rarotonga, the most modernized island, with those born on other, less modernized islands shows those born on Rarotonga to be taller, but not relatively heavier than those born elsewhere in the Cook Islands. Both males and females of the 1996 sample of adults are significantly taller, heavier, with higher BMI compared with the 1966 sample, indicating a secular trend toward increased body size across this 30-year period. The mean BMIs of the younger age groups in 1996 are greater than those of the same age groups in 1966, indicating a secular trend toward greater body fatness. There has been a significant increase in obesity among both males and females. In 1966, 14% of males had a BMI greater than 30, while in 1996, the proportion was 52%. Among females, 44% of those measured in 1966 had a BMI greater than 30, while in 1996 the proportion was 57%. The higher mean stature of younger adult males relative to older ones suggests that the secular trend toward increasing height may have been underway prior to 1966. The mean statures and weights of adults aged 60 years and older in the 1996 sample are more similar to values given for most age groups

  1. Development of an online database of typical food portion sizes in Irish population groups.

    PubMed

    Lyons, Jacqueline; Walton, Janette; Flynn, Albert

    2013-01-01

    The Irish Food Portion Sizes Database (available at www.iuna.net) describes typical portion weights for an extensive range of foods and beverages for Irish children, adolescents and adults. The present paper describes the methodologies used to develop the database and some key characteristics of the portion weight data contained therein. The data are derived from three large, cross-sectional food consumption surveys carried out in Ireland over the last decade: the National Children's Food Survey (2003-2004), National Teens' Food Survey (2005-2006) and National Adult Nutrition Survey (2008-2010). Median, 25th and 75th percentile portion weights are described for a total of 545 items across the three survey groups, split by age group or sex as appropriate. The typical (median) portion weights reported for adolescents and adults are similar for many foods, while those reported for children are notably smaller. Adolescent and adult males generally consume larger portions than their female counterparts, though similar portion weights may be consumed where foods are packaged in unit amounts (for example, pots of yoghurt). The inclusion of energy under-reporters makes little difference to the estimation of typical portion weights in adults. The data have wide-ranging applications in dietary assessment and food labelling, and will serve as a useful reference against which to compare future portion size data from the Irish population. The present paper provides a useful context for researchers and others wishing to use the Irish Food Portion Sizes Database, and may guide researchers in other countries in establishing similar databases of their own.

  2. Population estimate of the preantral follicles and frequency of multioocyte follicles in prepubertal and adult bitches.

    PubMed

    Lunardon, N T; Silva-Santos, K C; Justino, R C; Dessunti, G T; Seneda, M M; Martins, M I M

    2015-04-01

    Oocytes from preantral follicles could be an alternative for in vitro maturation because most follicles are at the preantral stage. There are few studies that have sought to estimate the number of preantral follicles in bitches. Therefore, the aims of this study were to estimate the population of preantral follicles in the ovaries of small- and medium-sized prepubertal and adult bitches and compare the population of preantral follicles between the right and left ovaries and evaluate the frequency of multioocyte follicles (MOF). Eighty ovaries were collected by elective ovariohysterectomy from 40 healthy bitches. The bitches were divided into four groups: small-size prepubertal bitches (<10 kg, n = 20), medium-size prepubertal bitches (10-20 kg, n = 20), small-size adult bitches (<10 kg, n = 20), and medium-size adult bitches (10-20 kg, n = 20). Immediately after surgery, the ovaries were fixed in Bouin's solution and processed for histology. For each specimen, 70 histologic sections were cut and mounted on slides; then, the number of preantral follicles was estimated using a correction factor. The preantral follicles were classified according to the developmental stage. The data were analyzed using the Kruskal-Wallis test followed by Dunn's test for comparison between groups, and Fisher's exact test was used to evaluate the frequency of MOF (P ≤ 0.05). Considering the population of preantral follicles from the pair of ovaries, medium-size prepubertal bitches had the highest (P < 0.05) population of preantral follicles compared with the small and medium-size adult groups. There was a large variation in the numbers of preantral follicles among individuals of the same weight and within each group. There were differences between medium-size prepubertal and adult bitches regarding the population of preantral follicles in the right ovaries (145,482 ± 110,712 vs. 49,500 ± 44,821; P = 0.02); however, no differences were observed between the

  3. Prevalence of Common Ocular Morbidities in Adult Population of Aligarh

    PubMed Central

    Haq, Inaamul; Khan, Zulfia; Khalique, Najam; Amir, Ali; Jilani, Fatima A; Zaidi, Meena

    2009-01-01

    Aims and Objectives: To determine the prevalence of common ocular morbidities (cataract, refractive errors, glaucoma, and corneal opacities) and their demographic and sociocultural correlates. Settings and Design: The present cross-sectional study was conducted in the field practice areas of the Department of Community Medicine, JNMC, AMU, Aligarh, for a period of one year, from September 2005 to August 2006. Materials and Methods: Systematic random sampling was done to select the required sample size. All adults aged 20 years and above in the selected households were interviewed and screened using a 6/9 illiterate ‘E’ chart. Those who could not read the ‘E’ chart were referred to the respective health training center for a complete eye examination by an ophthalmologist. Statistical Analysis: Chi- square test. Results: The prevalence of visual impairment, low vision, and blindness, based on presenting visual acuity was 13.0, 7.8, and 5.3%, respectively. The prevalence of cataract was 21.7%. Bilateral cataract was present in 16.9% of the population. Cataract was significantly associated with age, education, and fuel use. The prevalence of myopia, hypermetropia, and astigmatism was 11.5, 9.8, and 3.7%, respectively. Glaucoma was diagnosed in six patients, giving a prevalence rate of 0.9%. All the six patients of glaucoma were aged above 40 years. The prevalence of corneal opacity was 4.2%. Conclusion: There is a high prevalence of treatable or preventable morbidities such as cataract, refractive errors, and corneal opacity. PMID:20049295

  4. Population size and winter distribution of eastern American oystercatchers

    USGS Publications Warehouse

    Brown, S.C.; Schulte, Shiloh A.; Harrington, B.; Winn, Brad; Bart, J.; Howe, M.

    2005-01-01

    Conservation of the eastern subspecies of the American oystercatcher (Haematopus palliatus palliatus) is a high priority in the U.S. Shorebird Conservation Plan, but previous population estimates were unreliable, information on distribution and habitat associations during winter was incomplete, and methods for long-term monitoring had not been developed prior to this survey. We completed the aerial survey proposed in the U.S. Shorebird Conservation Plan to determine population size, winter distribution, and habitat associations. We conducted coastal aerial surveys from New Jersey to Texas during November 2002 to February 2003. This area comprised the entire wintering range of the eastern American oystercatcher within the United States. Surveys covered all suitable habitat in the United States for the subspecies, partitioned into 3 survey strata: known roost sites, high-use habitat, and inter-coastal tidal habitat. We determined known roost sites from extensive consultation with biologists and local experts in each state. High-use habitat included sand islands, sand spits at inlets, shell rakes, and oyster reefs. Partner organizations conducted ground counts in most states. We used high resolution still photography to determine detection rates for estimates of the number of birds in particular flocks, and we used ground counts to determine detection rates of flocks. Using a combination of ground and aerial counts, we estimated the population of eastern American oystercatchers to be 10,971 +/- 298. Aerial surveys can serve an important management function for shorebirds and possibly other coastal waterbirds by providing population status and trend information across a wide geographic scale.

  5. Scale-Dependent Habitat Selection and Size-Based Dominance in Adult Male American Alligators.

    PubMed

    Strickland, Bradley A; Vilella, Francisco J; Belant, Jerrold L

    2016-01-01

    Habitat selection is an active behavioral process that may vary across spatial and temporal scales. Animals choose an area of primary utilization (i.e., home range) then make decisions focused on resource needs within patches. Dominance may affect the spatial distribution of conspecifics and concomitant habitat selection. Size-dependent social dominance hierarchies have been documented in captive alligators, but evidence is lacking from wild populations. We studied habitat selection for adult male American alligators (Alligator mississippiensis; n = 17) on the Pearl River in central Mississippi, USA, to test whether habitat selection was scale-dependent and individual resource selectivity was a function of conspecific body size. We used K-select analysis to quantify selection at the home range scale and patches within the home range to determine selection congruency and important habitat variables. In addition, we used linear models to determine if body size was related to selection patterns and strengths. Our results indicated habitat selection of adult male alligators was a scale-dependent process. Alligators demonstrated greater overall selection for habitat variables at the patch level and less at the home range level, suggesting resources may not be limited when selecting a home range for animals in our study area. Further, diurnal habitat selection patterns may depend on thermoregulatory needs. There was no relationship between resource selection or home range size and body size, suggesting size-dependent dominance hierarchies may not have influenced alligator resource selection or space use in our sample. Though apparent habitat suitability and low alligator density did not manifest in an observed dominance hierarchy, we hypothesize that a change in either could increase intraspecific interactions, facilitating a dominance hierarchy. Due to the broad and diverse ecological roles of alligators, understanding the factors that influence their social dominance

  6. Scale-Dependent Habitat Selection and Size-Based Dominance in Adult Male American Alligators

    PubMed Central

    Strickland, Bradley A.; Vilella, Francisco J.; Belant, Jerrold L.

    2016-01-01

    Habitat selection is an active behavioral process that may vary across spatial and temporal scales. Animals choose an area of primary utilization (i.e., home range) then make decisions focused on resource needs within patches. Dominance may affect the spatial distribution of conspecifics and concomitant habitat selection. Size-dependent social dominance hierarchies have been documented in captive alligators, but evidence is lacking from wild populations. We studied habitat selection for adult male American alligators (Alligator mississippiensis; n = 17) on the Pearl River in central Mississippi, USA, to test whether habitat selection was scale-dependent and individual resource selectivity was a function of conspecific body size. We used K-select analysis to quantify selection at the home range scale and patches within the home range to determine selection congruency and important habitat variables. In addition, we used linear models to determine if body size was related to selection patterns and strengths. Our results indicated habitat selection of adult male alligators was a scale-dependent process. Alligators demonstrated greater overall selection for habitat variables at the patch level and less at the home range level, suggesting resources may not be limited when selecting a home range for animals in our study area. Further, diurnal habitat selection patterns may depend on thermoregulatory needs. There was no relationship between resource selection or home range size and body size, suggesting size-dependent dominance hierarchies may not have influenced alligator resource selection or space use in our sample. Though apparent habitat suitability and low alligator density did not manifest in an observed dominance hierarchy, we hypothesize that a change in either could increase intraspecific interactions, facilitating a dominance hierarchy. Due to the broad and diverse ecological roles of alligators, understanding the factors that influence their social dominance

  7. Population genomics of eusocial insects: the costs of a vertebrate-like effective population size.

    PubMed

    Romiguier, J; Lourenco, J; Gayral, P; Faivre, N; Weinert, L A; Ravel, S; Ballenghien, M; Cahais, V; Bernard, A; Loire, E; Keller, L; Galtier, N

    2014-03-01

    The evolution of reproductive division of labour and social life in social insects has lead to the emergence of several life-history traits and adaptations typical of larger organisms: social insect colonies can reach masses of several kilograms, they start reproducing only when they are several years old, and can live for decades. These features and the monopolization of reproduction by only one or few individuals in a colony should affect molecular evolution by reducing the effective population size. We tested this prediction by analysing genome-wide patterns of coding sequence polymorphism and divergence in eusocial vs. noneusocial insects based on newly generated RNA-seq data. We report very low amounts of genetic polymorphism and an elevated ratio of nonsynonymous to synonymous changes – a marker of the effective population size – in four distinct species of eusocial insects, which were more similar to vertebrates than to solitary insects regarding molecular evolutionary processes. Moreover, the ratio of nonsynonymous to synonymous substitutions was positively correlated with the level of social complexity across ant species. These results are fully consistent with the hypothesis of a reduced effective population size and an increased genetic load in eusocial insects, indicating that the evolution of social life has important consequences at both the genomic and population levels.

  8. Genome-Wide Estimates of Coancestry, Inbreeding and Effective Population Size in the Spanish Holstein Population

    PubMed Central

    Rodríguez-Ramilo, Silvia Teresa; Fernández, Jesús; Toro, Miguel Angel; Hernández, Delfino; Villanueva, Beatriz

    2015-01-01

    Estimates of effective population size in the Holstein cattle breed have usually been low despite the large number of animals that constitute this breed. Effective population size is inversely related to the rates at which coancestry and inbreeding increase and these rates have been high as a consequence of intense and accurate selection. Traditionally, coancestry and inbreeding coefficients have been calculated from pedigree data. However, the development of genome-wide single nucleotide polymorphisms has increased the interest of calculating these coefficients from molecular data in order to improve their accuracy. In this study, genomic estimates of coancestry, inbreeding and effective population size were obtained in the Spanish Holstein population and then compared with pedigree-based estimates. A total of 11,135 animals genotyped with the Illumina BovineSNP50 BeadChip were available for the study. After applying filtering criteria, the final genomic dataset included 36,693 autosomal SNPs and 10,569 animals. Pedigree data from those genotyped animals included 31,203 animals. These individuals represented only the last five generations in order to homogenise the amount of pedigree information across animals. Genomic estimates of coancestry and inbreeding were obtained from identity by descent segments (coancestry) or runs of homozygosity (inbreeding). The results indicate that the percentage of variance of pedigree-based coancestry estimates explained by genomic coancestry estimates was higher than that for inbreeding. Estimates of effective population size obtained from genome-wide and pedigree information were consistent and ranged from about 66 to 79. These low values emphasize the need of controlling the rate of increase of coancestry and inbreeding in Holstein selection programmes. PMID:25880228

  9. Genome-wide estimates of coancestry, inbreeding and effective population size in the Spanish Holstein population.

    PubMed

    Rodríguez-Ramilo, Silvia Teresa; Fernández, Jesús; Toro, Miguel Angel; Hernández, Delfino; Villanueva, Beatriz

    2015-01-01

    Estimates of effective population size in the Holstein cattle breed have usually been low despite the large number of animals that constitute this breed. Effective population size is inversely related to the rates at which coancestry and inbreeding increase and these rates have been high as a consequence of intense and accurate selection. Traditionally, coancestry and inbreeding coefficients have been calculated from pedigree data. However, the development of genome-wide single nucleotide polymorphisms has increased the interest of calculating these coefficients from molecular data in order to improve their accuracy. In this study, genomic estimates of coancestry, inbreeding and effective population size were obtained in the Spanish Holstein population and then compared with pedigree-based estimates. A total of 11,135 animals genotyped with the Illumina BovineSNP50 BeadChip were available for the study. After applying filtering criteria, the final genomic dataset included 36,693 autosomal SNPs and 10,569 animals. Pedigree data from those genotyped animals included 31,203 animals. These individuals represented only the last five generations in order to homogenise the amount of pedigree information across animals. Genomic estimates of coancestry and inbreeding were obtained from identity by descent segments (coancestry) or runs of homozygosity (inbreeding). The results indicate that the percentage of variance of pedigree-based coancestry estimates explained by genomic coancestry estimates was higher than that for inbreeding. Estimates of effective population size obtained from genome-wide and pedigree information were consistent and ranged from about 66 to 79. These low values emphasize the need of controlling the rate of increase of coancestry and inbreeding in Holstein selection programmes.

  10. Orthodontic treatment need in a Spanish young adult population

    PubMed Central

    Montiel-Company, José M.; Manzanera-Pastor, David; Almerich-Silla, José M.

    2012-01-01

    Objectives: Orthodontic treatment need has often been assessed in child populations, but few studies employing internationally-recognized indices have been conducted in adult or young adult populations. The aim of this study was to determine the orthodontic treatment need of a young adult population in Spain by means of the Dental Aesthetic Index (DAI), the Index of Orthodontic Treatment Need (IOTN) and the need perceived by the patients. Study design: A cross-sectional epidemiological study was conducted in a broad, representative sample of 671 adults aged between 35 and 44 years using health centers in the Valencia Region of Spain, following the recommendations of the World Health Organization (WHO). Results: Orthodontic treatment was required by 31.3% of the sample according to the DAI and 19.2% according to the IOTN (DHC). The orthodontic treatment need perceived by the patients was 21.1%. On relating treatment need to different variables, significant differences in patient perception were encountered by gender, as women perceived a greater need (23.9%) than men (14.4%). Significant differences in previous orthodontic treatment history were found between middle/high (15%) and low (9%) social class and between secondary/tertiary (14%) and primary (3.3%) education. Conclusions: There was no agreement between the treatment need assessed objectively by the indices and that perceived by the patient, or between the indices themselves. The decision to undergo orthodontic treatment can depend on socioeconomic and psychological factors and on values and principles that do not easily lend themselves to objective measurement. Key words:Orthodontics, epidemiology, adult, malocclusion. PMID:22322504

  11. THE MASSIVE SATELLITE POPULATION OF MILKY-WAY-SIZED GALAXIES

    SciTech Connect

    Rodriguez-Puebla, Aldo; Avila-Reese, Vladimir; Drory, Niv

    2013-08-20

    subhalos should agree with the abundance of massive satellites in all MW-sized hosts, i.e., there is not a missing (massive) satellite problem for the {Lambda}CDM cosmology. However, we confirm that the maximum circular velocity, v{sub max}, of the subhalos of satellites smaller than m{sub *} {approx} 10{sup 8} M{sub Sun} is systematically larger than the v{sub max} inferred from current observational studies of the MW bright dwarf satellites; different from previous works, this conclusion is based on an analysis of the overall population of MW-sized galaxies. Some pieces of evidence suggest that the issue could refer only to satellite dwarfs but not to central dwarfs, then environmental processes associated with dwarfs inside host halos combined with supernova-driven core expansion should be on the basis of the lowering of v{sub max}.

  12. The relationship between social network body size and the body size norms of Black and Hispanic adults

    PubMed Central

    Winston, Ginger; Phillips, Erica; Wethington, Elaine; Wells, Martin; Devine, Carol M.; Peterson, Janey; Wansink, Brian; Ramos, Rosio; Charlson, Mary

    2015-01-01

    Objective To examine the relationship between the body size norms of Black and Hispanic adults and the body sizes of their social network members. Methods Egocentric network data were examined for 245 adults recruited from 2012–2013 in New York City. A multivariable regression model was used to examine the relationship between participants' perception of normal body size and the body sizes of their network members adjusted for participant age, education, race/ethnicity and network size. Participants' body size norms were also examined stratified by the following characteristics of obese network members: frequency of contact, living proximity, relationship, and importance of relationship. Results Index participants were 89% female with mean body mass index 33.5 kg/m2. There were 2571 network members identified (31% overweight, 10% obese). In the fully adjusted multivariable model, perception of normal body size increased as the number of network members with obesity increased (p < 0.01). Larger body size norms were associated with increased frequency of contact with obese network members (p = 0.04), and obese members living in the home (p = 0.049). Conclusions These findings support a relationship between the body size norms of Black and Hispanic adults and their social network body size. PMID:26705513

  13. Effective size of a wild salmonid population is greatly reduced by hatchery supplementation.

    PubMed

    Christie, M R; Marine, M L; French, R A; Waples, R S; Blouin, M S

    2012-10-01

    Many declining and commercially important populations are supplemented with captive-born individuals that are intentionally released into the wild. These supplementation programs often create large numbers of offspring from relatively few breeding adults, which can have substantial population-level effects. We examined the genetic effects of supplementation on a wild population of steelhead (Oncorhynchus mykiss) from the Hood River, Oregon, by matching 12 run-years of hatchery steelhead back to their broodstock parents. We show that the effective number of breeders producing the hatchery fish (broodstock parents; N(b)) was quite small (harmonic mean N(b)=25 fish per brood-year vs 373 for wild fish), and was exacerbated by a high variance in broodstock reproductive success among individuals within years. The low N(b) caused hatchery fish to have decreased allelic richness, increased average relatedness, more loci in linkage disequilibrium and substantial levels of genetic drift in comparison with their wild-born counterparts. We also documented a substantial Ryman-Laikre effect whereby the additional hatchery fish doubled the total number of adult fish on the spawning grounds each year, but cut the effective population size of the total population (wild and hatchery fish combined) by nearly two-thirds. We further demonstrate that the Ryman-Laikre effect is most severe in this population when (1) >10% of fish allowed onto spawning grounds are from hatcheries and (2) the hatchery fish have high reproductive success in the wild. These results emphasize the trade-offs that arise when supplementation programs attempt to balance disparate goals (increasing production while maintaining genetic diversity and fitness).

  14. Critical and Demographic Effective Population Size of African Buffalo (Syncerus caffer) in Borgu Sector of Kainji Lake National Park, Nigeria

    NASA Astrophysics Data System (ADS)

    Aremu, O. T.; Onadeko, S. A.; Ola-Adams, B. A.; Inah, E. I.

    Effective population size of African Buffalo (Syncerus caffer) was estimated using Franklin and Frankham model. Buffalo relative abundance was calculated using a 4x4 km transect constructed in each of the identified six vegetation communities in the Park, which were traversed once a month for a period of 24 months. The results revealed that the relative abundance of Buffalo in the Park was 0.372±0.03 groups km-2 consisting of 51±5.827 groups representing 242±16.309 individuals which consist of 30 adult males and 70 adult females representing 12.40 and 28.93%, respectively of the total Buffalo population in the Park which was considered to be the effective breeding population size. The composition of the population structure was significantly different (p< 0.05). The effective population size of Buffalo in the Park was estimated to be 581.34±4.91 which was above the recommended value of 100 which shows that the Buffalo population in the Park was not threatened by demographic stochasticity factors but rather by illegal human activities in the Park. Measures to improve conservation and management of the existing Buffalo population in the Park are also discussed.

  15. Habitat-specific size structure variations in periwinkle populations ( Littorina littorea) caused by biotic factors

    NASA Astrophysics Data System (ADS)

    Eschweiler, Nina; Molis, Markus; Buschbaum, Christian

    2009-06-01

    Shell size distribution patterns of marine gastropod populations may vary considerably across different environments. We investigated the size and density structure of genetically continuous periwinkle populations ( Littorina littorea) on an exposed rocky and a sheltered sedimentary environment on two nearby islands in the south-eastern North Sea (German Bight). On the sedimentary shore, periwinkle density (917 ± 722 individuals m-2) was about three times higher than on the rocky shore (296 ± 168 individuals m-2). Mean (9.8 ± 3.9 mm) and maximum (22 mm) shell size of L. littorea on the sedimentary shore were smaller than on the rocky shore (21.5 ± 4.2 and 32 mm, respectively), where only few small snails were found. Additionally, periwinkle shells were thicker and stronger on the rocky than on the sedimentary shore. To ascertain mechanisms responsible for differences in population structures, we examined periwinkles in both environments for growth rate, predation pressure, infection with a shell boring polychaete ( Polydora ciliata) and parasitic infestation by trematodes. A crosswise transplantation experiment revealed better growth conditions on the sedimentary than on the rocky shore. However, crab abundance and prevalence of parasites and P. ciliata in adult snails were higher on the sedimentary shore. Previous investigations showed that crabs prefer large periwinkles infested with P. ciliata. Thus, we suggest that parasites and shell boring P. ciliata in conjunction with an increased crab predation pressure are responsible for low abundances of large periwinkles on the sedimentary shore while high wave exposure may explain low densities of juvenile L. littorea on the rocky shore. We conclude that biotic factors may strongly contribute to observed differences in size structure of the L. littorea populations studied on rocky and sedimentary shores.

  16. Making It Count: Improving Estimates of the Size of Transgender and Gender Nonconforming Populations.

    PubMed

    Deutsch, Madeline B

    2016-06-01

    An accurate estimate of the number of transgender and gender nonconforming people is essential to inform policy and funding priorities and decisions. Historical reports of population sizes of 1 in 4000 to 1 in 50,000 have been based on clinical populations and likely underestimate the size of the transgender population. More recent population-based studies have found a 10- to 100-fold increase in population size. Studies that estimate population size should be population based, employ the two-step method to allow for collection of both gender identity and sex assigned at birth, and include measures to capture the range of transgender people with nonbinary gender identities.

  17. Making It Count: Improving Estimates of the Size of Transgender and Gender Nonconforming Populations.

    PubMed

    Deutsch, Madeline B

    2016-06-01

    An accurate estimate of the number of transgender and gender nonconforming people is essential to inform policy and funding priorities and decisions. Historical reports of population sizes of 1 in 4000 to 1 in 50,000 have been based on clinical populations and likely underestimate the size of the transgender population. More recent population-based studies have found a 10- to 100-fold increase in population size. Studies that estimate population size should be population based, employ the two-step method to allow for collection of both gender identity and sex assigned at birth, and include measures to capture the range of transgender people with nonbinary gender identities. PMID:27135657

  18. Evolutionary divergence of adult body size and juvenile growth in sympatric subpopulations of a top predator in aquatic ecosystems.

    PubMed

    Tibblin, Petter; Forsman, Anders; Koch-Schmidt, Per; Nordahl, Oscar; Johannessen, Peter; Nilsson, Jonas; Larsson, Per

    2015-07-01

    Evolutionary theory predicts that different selective regimes may contribute to divergent evolution of body size and growth rate among populations, but most studies have focused on allopatric populations. Here, we studied five sympatric subpopulations of anadromous northern pike (Esox lucius) in the Baltic Sea subjected to allopatric habitats for a short period of their life cycle due to homing behavior. We report differences in adult body size among subpopulations that were in part due to variation in growth rate. Body size of emigrating juveniles also differed among subpopulations, and differences remained when individuals were reared in a common environment, thus indicating evolutionary divergence among subpopulations. Furthermore, a QST-FST comparison indicated that differences had evolved due to divergent selection rather than genetic drift, possibly in response to differences in selective mortality among spawning habitats during the allopatric life stage. Adult and juvenile size were negatively correlated across subpopulations, and reconstruction of growth trajectories of adult fishes suggested that body size differences developed gradually and became accentuated throughout the first years of life. These results represent rare evidence that sympatric subpopulations can evolve differences in key life-history traits despite being subjected to allopatric habitats during only a very short fraction of their life.

  19. Socioeconomic status, body size and physical activity of adults on Rarotonga, the Cook Islands.

    PubMed

    Ulijaszek, S J

    2001-01-01

    Much of the secular trend toward increased body size among populations in the Pacific Region has been attributed to the processes of economic modernization and socioeconomic change. The primary objective of the present analysis was to examine the relationships between socioeconomic factors and stature, weight, body mass index and physical activity level of adult Cook Islanders living a largely modernized lifestyle in the Pacific Region. In a cross-sectional study of physical activity, body size and socioeconomic status, a volunteer sample of 345 Cook Islanders aged 20-65 years was obtained from the total adult population of Rarotonga, and measured at six out-patient clinics. Stature, weight, body mass index (BMI), physical activity level and age were calculated by sex and occupational category, years of education, island of birth and number of years lived on Rarotonga, respectively, using SPSSPC for Windows. Stepwise multiple regression was used to examine the relationships between stature, weight, BMI, PALweekday (a measure of physical activity level), age and non-linear functions of age, and the socioeconomic variables. These analyses indicate that the secular trend in stature is a function of the relative level of modernization on Rarotonga relative to other Cook Islands, and with level of education. These factors associate differently among males and females, the secular trend among males appearing to be a general phenomenon in response to lifestyle change associated with life on Rarotonga, while among females the trend is a function of lifestyle change associated with education and independent of island of origin. The trend toward increasing body fatness is also different for males and females. Weight declines with age for both men and women, in a linear way for the males, but in a non-linear fashion for the females. Body weight is also greater among those males in more skilled and professional occupations than among those with less-skilled professions. For

  20. How many steps/day are enough? For older adults and special populations

    PubMed Central

    2011-01-01

    Older adults and special populations (living with disability and/or chronic illness that may limit mobility and/or physical endurance) can benefit from practicing a more physically active lifestyle, typically by increasing ambulatory activity. Step counting devices (accelerometers and pedometers) offer an opportunity to monitor daily ambulatory activity; however, an appropriate translation of public health guidelines in terms of steps/day is unknown. Therefore this review was conducted to translate public health recommendations in terms of steps/day. Normative data indicates that 1) healthy older adults average 2,000-9,000 steps/day, and 2) special populations average 1,200-8,800 steps/day. Pedometer-based interventions in older adults and special populations elicit a weighted increase of approximately 775 steps/day (or an effect size of 0.26) and 2,215 steps/day (or an effect size of 0.67), respectively. There is no evidence to inform a moderate intensity cadence (i.e., steps/minute) in older adults at this time. However, using the adult cadence of 100 steps/minute to demark the lower end of an absolutely-defined moderate intensity (i.e., 3 METs), and multiplying this by 30 minutes produces a reasonable heuristic (i.e., guiding) value of 3,000 steps. However, this cadence may be unattainable in some frail/diseased populations. Regardless, to truly translate public health guidelines, these steps should be taken over and above activities performed in the course of daily living, be of at least moderate intensity accumulated in minimally 10 minute bouts, and add up to at least 150 minutes over the week. Considering a daily background of 5,000 steps/day (which may actually be too high for some older adults and/or special populations), a computed translation approximates 8,000 steps on days that include a target of achieving 30 minutes of moderate-to-vigorous physical activity (MVPA), and approximately 7,100 steps/day if averaged over a week. Measured directly and

  1. Same size--same niche? Foraging niche separation between sympatric juvenile Galapagos sea lions and adult Galapagos fur seals.

    PubMed

    Jeglinski, Jana W E; Goetz, Kimberley T; Werner, Christiane; Costa, Daniel P; Trillmich, Fritz

    2013-05-01

    1. In vertebrates, patterns of resource utilization change throughout development according to age- and or size-specific abilities and requirements. Thus, interspecific competition affects different age classes differently. 2. Adults of sympatric species often show distinct foraging niche segregation, but juvenile resource use might overlap with adult competitors of similar body size. Resultant negative effects on juveniles can have important consequences for population dynamics, yet such interactions have received little attention in studies of mammalian communities. 3. Using GPS tracking devices, time-depth recorders and stable isotope data, we compared diving depth, activity time, trophic position and foraging habitat characteristics to investigate foraging niche overlap between similar-sized sympatric juvenile Galapagos sea lions (Zalophus wollebaeki) and adult Galapagos fur seals (Arctocephalus galapagoensis) and compared each group with much larger-bodied adult Galapagos sea lions. 4. We found little indication for direct competition but a complex pattern of foraging niche segregation: juvenile sea lions and adult fur seals dived to shallow depths at night, but foraged in different habitats with limited spatial overlap. Conversely, juvenile and adult sea lions employed different foraging patterns, but their foraging areas overlapped almost completely. 5. Consistency of foraging habitat characteristics between juvenile and adult sea lions suggests that avoidance of competition may be important in shaping foraging habitat utilization. Resultant specialization on a limited habitat could contribute to low sea lion numbers that contrast with high fur seal abundance. Our data suggest that exploitation by multiple predators within spatially restricted foraging ranges of juveniles might negatively impact juvenile foraging success and ultimately influence population dynamics.

  2. Survival and population size of a resident bird species are declining as temperature increases.

    PubMed

    Santisteban, Leonard; Benkman, Craig W; Fetz, Trevor; Smith, Julie W

    2012-03-01

    1. A large number of migratory bird species appear to be declining as the result of climate change, but whether resident bird species have or will be adversely affected by climate change is less clear. We focus on the South Hills crossbill (Loxia curvirostra complex), which is endemic to about 70 km(2) of Rocky Mountain lodgepole pine (Pinus contorta latifolia) forest in southern Idaho, USA. 2. Our results indicate that the South Hills crossbill has declined by over 60% between 2003 and 2008, and that decreasing adult survival drives this population decline. 3. We evaluated the relative support for multiple hypotheses linking crossbill survival to climate, an ectoparasitic mite (scaly-leg mites Knemidokoptes jamaicensis), and the recent emergence of West Nile virus. Changes in adult apparent survival rate were closely associated with average spring and annual temperatures, and with high temperatures (≥32 °C) during summer, which have increased during the last decade. In contrast, there was little evidence that scaly-leg mites or West Nile virus contributed to recent declines in adult survival. 4. The most probable mechanism causing the decline in adult survival and population size is a decrease in the availability of their primary food resource, seeds in serotinous pine cones. Cone production has declined with increasing annual temperatures, and these cones appear to be prematurely opening owing to increasingly hot summer conditions releasing their seeds and reducing the carrying capacity for crossbills later in the year. 5. In light of regional climate change forecasts, which include an increase in both annual temperature and hot days (>32 °C), and the likely disappearance of lodgepole pine from southern Idaho by the end of this century, additional research is needed to determine how to maintain lodgepole pine forests and their supply of seeds to conserve one of the few bird species endemic to the continental United States.

  3. Survival and population size of a resident bird species are declining as temperature increases.

    PubMed

    Santisteban, Leonard; Benkman, Craig W; Fetz, Trevor; Smith, Julie W

    2012-03-01

    1. A large number of migratory bird species appear to be declining as the result of climate change, but whether resident bird species have or will be adversely affected by climate change is less clear. We focus on the South Hills crossbill (Loxia curvirostra complex), which is endemic to about 70 km(2) of Rocky Mountain lodgepole pine (Pinus contorta latifolia) forest in southern Idaho, USA. 2. Our results indicate that the South Hills crossbill has declined by over 60% between 2003 and 2008, and that decreasing adult survival drives this population decline. 3. We evaluated the relative support for multiple hypotheses linking crossbill survival to climate, an ectoparasitic mite (scaly-leg mites Knemidokoptes jamaicensis), and the recent emergence of West Nile virus. Changes in adult apparent survival rate were closely associated with average spring and annual temperatures, and with high temperatures (≥32 °C) during summer, which have increased during the last decade. In contrast, there was little evidence that scaly-leg mites or West Nile virus contributed to recent declines in adult survival. 4. The most probable mechanism causing the decline in adult survival and population size is a decrease in the availability of their primary food resource, seeds in serotinous pine cones. Cone production has declined with increasing annual temperatures, and these cones appear to be prematurely opening owing to increasingly hot summer conditions releasing their seeds and reducing the carrying capacity for crossbills later in the year. 5. In light of regional climate change forecasts, which include an increase in both annual temperature and hot days (>32 °C), and the likely disappearance of lodgepole pine from southern Idaho by the end of this century, additional research is needed to determine how to maintain lodgepole pine forests and their supply of seeds to conserve one of the few bird species endemic to the continental United States. PMID:22010811

  4. Population size, survival, and movements of white-cheeked pintails in Eastern Puerto Rico

    USGS Publications Warehouse

    Collazo, J.A.; Bonilla-Martinez, G.

    2001-01-01

    We estimated numbers and survival of White-cheeked Pintails (Anas bahamensis) in eastern Puerto Rico during 1996-1999. We also quantified their movements between Culebra Island and the Humacao Wildlife Refuge, Puerto Rico. Mark-resight population size estimates averaged 1020 pintails during nine, 3-month sampling periods from January 1997 to June 1999. On average, minimum regional counts were 38 % lower than mark-resight estimates (mean = 631). Adult survival was 0.51 ?? 0.09 (SE). This estimate is similar for other anatids of similar size but broader geographic distribution. The probability of pintails surviving and staying in Humacao was hiher (67 %) than for counterparts on Culebra (31 %). The probability of surviving and moving from Culebra to Humacao (41 %) was higher than from Humacao to Culebra (20 %). These findings, and available information on reproduction, indicate that the Humacao Wildlife Refuge refuge has an important role in the regional demography of pintails. Our findings on population numbers and regional survival are encouraging, given concerns about the species' status due to habitat loss and hunting. However, our outlook for the species is tempered by the remaining gaps in the population dynamics of pintails; for examples, survival estimates of broods and fledglings (age 0-1) are needed for a comprehensive status assessment. Until additional data are obtianed, White-cheeked Pintails should continue to be protectd from hunting in Puerto Rico.

  5. [Prolonged fever: specific issues in the young adult population].

    PubMed

    Carmoi, T; Grateau, G; Billhot, M; Dumas, G; Biale, L; Perrot, G; Algayres, J-P

    2010-12-01

    Early studies on prolonged fever date back to the 1960s. Fifty years later, prolonged unexplained fever remains a diagnostic challenge to the general internists. Although the aetiologies of prolonged fevers have not changed much in the general population, the distribution between the various causes is not the same anymore. A regular decrease in infectious and neoplastic causes is noticed whatever the age. Prolonged fevers related to inflammatory disorders and fevers that remain of unknown origin still represent approximately 30 to 50% of the cases. In the young adult population, as in the older patients, prolonged fevers can be attributed to four groups: infection, inflammation, neoplasic and other aetiologies (including drug-related fevers). In the young adult population, the management of prolonged fever presents some specific issues that are the purpose of this review coupled with our own experience. The prognosis of undiagnosed prolonged fever is usually favourable, as a life-threatening aetiology is exceptionally diagnosed during the follow-up if the initial management was complete and accurate.

  6. [Obesity in adults: a population based study in a small town in South of Brazil, 2005].

    PubMed

    Sarturi, Juliana Barbosa; das Neves, Janaina; Peres, Karen Glazer

    2010-01-01

    Changes in nutritional pattern in Brazilian population have been observed mainly in relation to obesity increase. This study aims to estimate the prevalence of obesity and associated factors in adult population in Santo Angelo, Rio Grande do Sul State, 2005. A cross sectional study was carried out involving adult subjects from 20 to 59 years old (n=434), of both sexes. People with Body Mass Index equal to or higher than 30 kg/m(2) were considered obese. A questionnaire was applied to collect data related to socioeconomic, demographic, and behavioral conditions. The multiple logistic regression analysis was performed to identify the associated factors. The response rate was 95.0% and the prevalence of obesity was equal to 16.6% (CI 95% 13.120.1). Presence of obesity was positively associated with lack of physical activity, none feeding habits care, and some individuals that mentioned current health problems regardless of sex. The prevalence of obesity found was similar to other Brazilian population based studies. The results may support planning and implementing prevention actions as well as obesity control in adult population taking into account the relevant details of a small size town.

  7. Correlated evolution of life-history with size at maturity in Daphnia pulicaria: patterns within and between populations.

    PubMed

    Baer, Charles F; Lynch, Michael

    2003-04-01

    Explaining the repeated evolution of similar sets of traits under similar environmental conditions is an important issue in evolutionary biology. The extreme alternative classes of explanations for correlated suites of traits are optimal adaptation and genetic constraint resulting from pleiotropy. Adaptive explanations presume that individual traits are free to evolve to their local optima and that convergent evolution represents particularly adaptive combinations of traits. Alternatively, if pleiotropy is strong and difficult to break, strong selection on one or a few particularly important characters would be expected to result in consistent correlated evolution of associated traits. If pleiotropy is common, we predict that the pattern of divergence among populations will consistently reflect the within-population genetic architecture. To test the idea that the multivariate life-history phenotype is largely a byproduct of strong selection on body size, we imposed divergent artificial selection on size at maturity upon two populations of the cladoceran Daphnia pulicaria, chosen on the basis of their extreme divergence in body size. Overall, the trajectory of divergence between the two natural populations did not differ from that predicted by the genetic architecture within each population. However, the pattern of correlated responses suggested the presence of strong pleiotropic constraints only for adult body size and not for other life-history traits. One trait, offspring size, appears to have evolved in a way different from that expected from the within-population genetic architecture and may be under stabilizing selection.

  8. Elevational variation in adult body size and growth rate but not in metabolic rate in the tree weta Hemideina crassidens.

    PubMed

    Bulgarella, Mariana; Trewick, Steven A; Godfrey, A Jonathan R; Sinclair, Brent J; Morgan-Richards, Mary

    2015-04-01

    Populations of the same species inhabiting distinct localities experience different ecological and climatic pressures that might result in differentiation in traits, particularly those related to temperature. We compared metabolic rate (and its thermal sensitivity), growth rate, and body size among nine high- and low-elevation populations of the Wellington tree weta, Hemideina crassidens, distributed from 9 to 1171 m a.s.l across New Zealand. Our results did not indicate elevational compensation in metabolic rates (metabolic cold adaptation). Cold acclimation decreased metabolic rate compared to warm-acclimated individuals from both high- and low-elevation populations. However, we did find countergradient variation in growth rates, with individuals from high-elevation populations growing faster and to a larger final size than individuals from low-elevation populations. Females grew faster to a larger size than males, although as adults their metabolic rates did not differ significantly. The combined physiological and morphological data suggest that high-elevation individuals grow quickly and achieve larger size while maintaining metabolic rates at levels not significantly different from low-elevation individuals. Thus, morphological differentiation among tree weta populations, in concert with genetic variation, might provide the material required for adaptation to changing conditions.

  9. Local extinction and recolonization, species effective population size, and modern human origins.

    PubMed

    Eller, Elise; Hawks, John; Relethford, John H

    2004-10-01

    A primary objection from a population genetics perspective to a multiregional model of modern human origins is that the model posits a large census size, whereas genetic data suggest a small effective population size. The relationship between census size and effective size is complex, but arguments based on an island model of migration show that if the effective population size reflects the number of breeding individuals and the effects of population subdivision, then an effective population size of 10,000 is inconsistent with the census size of 500,000 to 1,000,000 that has been suggested by archeological evidence. However, these models have ignored the effects of population extinction and recolonization, which increase the expected variance among demes and reduce the inbreeding effective population size. Using models developed for population extinction and recolonization, we show that a large census size consistent with the multiregional model can be reconciled with an effective population size of 10,000, but genetic variation among demes must be high, reflecting low interdeme migration rates and a colonization process that involves a small number of colonists or kin-structured colonization. Ethnographic and archeological evidence is insufficient to determine whether such demographic conditions existed among Pleistocene human populations, and further work needs to be done. More realistic models that incorporate isolation by distance and heterogeneity in extinction rates and effective deme sizes also need to be developed. However, if true, a process of population extinction and recolonization has interesting implications for human demographic history.

  10. Thermal evolution of pre-adult life history traits, geometric size and shape, and developmental stability in Drosophila subobscura.

    PubMed

    Santos, M; Brites, D; Laayouni, H

    2006-11-01

    Replicated lines of Drosophila subobscura originating from a large outbred stock collected at the estimated Chilean epicentre (Puerto Montt) of the original New World invasion were allowed to evolve under controlled conditions of larval crowding for 3.5 years at three temperature levels (13, 18 and 22 degrees C). Several pre-adult life history traits (development time, survival and competitive ability), adult life history related traits (wing size, wing shape and wing-aspect ratio), and wing size and shape asymmetries were measured at the three temperatures. Cold-adapted (13 degrees C) populations evolved longer development times and showed lower survival at the highest developmental temperature. No divergence for wing size was detected following adaptation to temperature extremes (13 and 22 degrees C), in agreement with earlier observations, but wing shape changes were obvious as a result of both thermal adaptation and development at different temperatures. However, the evolutionary trends observed for the wing-aspect ratio were inconsistent with an adaptive hypothesis. There was some indication that wing shape asymmetry has evolutionarily increased in warm-adapted populations, which suggests that there is additive genetic variation for fluctuating asymmetry and that it can evolve under rapid environmental changes caused by thermal stress. Overall, our results cast strong doubts on the hypothesis that body size itself is the target of selection, and suggest that pre-adult life history traits are more closely related to thermal adaptation.

  11. Simple life-history traits explain key effective population size ratios across diverse taxa

    PubMed Central

    Waples, Robin S.; Luikart, Gordon; Faulkner, James R.; Tallmon, David A.

    2013-01-01

    Effective population size (Ne) controls both the rate of random genetic drift and the effectiveness of selection and migration, but it is difficult to estimate in nature. In particular, for species with overlapping generations, it is easier to estimate the effective number of breeders in one reproductive cycle (Nb) than Ne per generation. We empirically evaluated the relationship between life history and ratios of Ne, Nb and adult census size (N) using a recently developed model (agene) and published vital rates for 63 iteroparous animals and plants. Nb/Ne varied a surprising sixfold across species and, contrary to expectations, Nb was larger than Ne in over half the species. Up to two-thirds of the variance in Nb/Ne and up to half the variance in Ne/N was explained by just two life-history traits (age at maturity and adult lifespan) that have long interested both ecologists and evolutionary biologists. These results provide novel insights into, and demonstrate a close general linkage between, demographic and evolutionary processes across diverse taxa. For the first time, our results also make it possible to interpret rapidly accumulating estimates of Nb in the context of the rich body of evolutionary theory based on Ne per generation. PMID:23926150

  12. Population genetic structure, linkage disequilibrium and effective population size of conserved and extensively raised village chicken populations of Southern Africa.

    PubMed

    Khanyile, Khulekani S; Dzomba, Edgar F; Muchadeyi, Farai C

    2015-01-01

    Extensively raised village chickens are considered a valuable source of biodiversity, with genetic variability developed over thousands of years that ought to be characterized and utilized. Surveys that can reveal a population's genetic structure and provide an insight into its demographic history will give valuable information that can be used to manage and conserve important indigenous animal genetic resources. This study reports population diversity and structure, linkage disequilibrium and effective population sizes of Southern African village chickens and conservation flocks from South Africa. DNA samples from 312 chickens from South African village and conservation flocks (n = 146), Malawi (n = 30) and Zimbabwe (n = 136) were genotyped using the Illumina iSelect chicken SNP60K BeadChip. Population genetic structure analysis distinguished the four conservation flocks from the village chicken populations. Of the four flocks, the Ovambo clustered closer to the village chickens particularly those sampled from South Africa. Clustering of the village chickens followed a geographic gradient whereby South African chickens were closer to those from Zimbabwe than to chickens from Malawi. Different conservation flocks seemed to have maintained different components of the ancestral genomes with a higher proportion of village chicken diversity found in the Ovambo population. Overall population LD averaged over chromosomes ranged from 0.03 ± 0.07 to 0.58 ± 0.41 and averaged 0.15 ± 0.16. Higher LD, ranging from 0.29 to 0.36, was observed between SNP markers that were less than 10 kb apart in the conservation flocks. LD in the conservation flocks steadily decreased to 0.15 (PK) and 0.24 (VD) at SNP marker interval of 500 kb. Genomewide LD decay in the village chickens from Malawi, Zimbabwe and South Africa followed a similar trend as the conservation flocks although the mean LD values for the investigated SNP intervals were lower. The results suggest low effective

  13. Population genetic structure, linkage disequilibrium and effective population size of conserved and extensively raised village chicken populations of Southern Africa

    PubMed Central

    Khanyile, Khulekani S.; Dzomba, Edgar F.; Muchadeyi, Farai C.

    2015-01-01

    Extensively raised village chickens are considered a valuable source of biodiversity, with genetic variability developed over thousands of years that ought to be characterized and utilized. Surveys that can reveal a population's genetic structure and provide an insight into its demographic history will give valuable information that can be used to manage and conserve important indigenous animal genetic resources. This study reports population diversity and structure, linkage disequilibrium and effective population sizes of Southern African village chickens and conservation flocks from South Africa. DNA samples from 312 chickens from South African village and conservation flocks (n = 146), Malawi (n = 30) and Zimbabwe (n = 136) were genotyped using the Illumina iSelect chicken SNP60K BeadChip. Population genetic structure analysis distinguished the four conservation flocks from the village chicken populations. Of the four flocks, the Ovambo clustered closer to the village chickens particularly those sampled from South Africa. Clustering of the village chickens followed a geographic gradient whereby South African chickens were closer to those from Zimbabwe than to chickens from Malawi. Different conservation flocks seemed to have maintained different components of the ancestral genomes with a higher proportion of village chicken diversity found in the Ovambo population. Overall population LD averaged over chromosomes ranged from 0.03 ± 0.07 to 0.58 ± 0.41 and averaged 0.15 ± 0.16. Higher LD, ranging from 0.29 to 0.36, was observed between SNP markers that were less than 10 kb apart in the conservation flocks. LD in the conservation flocks steadily decreased to 0.15 (PK) and 0.24 (VD) at SNP marker interval of 500 kb. Genomewide LD decay in the village chickens from Malawi, Zimbabwe and South Africa followed a similar trend as the conservation flocks although the mean LD values for the investigated SNP intervals were lower. The results suggest low effective

  14. Landscape Simplification Constrains Adult Size in a Native Ground-Nesting Bee

    PubMed Central

    Renauld, Miles; Hutchinson, Alena; Loeb, Gregory; Poveda, Katja; Connelly, Heather

    2016-01-01

    Bees provide critical pollination services to 87% of angiosperm plants; however, the reliability of these services may become threatened as bee populations decline. Agricultural intensification, resulting in the simplification of environments at the landscape scale, greatly changes the quality and quantity of resources available for female bees to provision their offspring. These changes may alter or constrain the tradeoffs in maternal investment allocation between offspring size, number and sex required to maximize fitness. Here we investigate the relationship between landscape scale agricultural intensification and the size and number of individuals within a wild ground nesting bee species, Andrena nasonii. We show that agricultural intensification at the landscape scale was associated with a reduction in the average size of field collected A. nasonii adults in highly agricultural landscapes but not with the number of individuals collected. Small females carried significantly smaller (40%) pollen loads than large females, which is likely to have consequences for subsequent offspring production and fitness. Thus, landscape simplification is likely to constrain allocation of resources to offspring through a reduction in the overall quantity, quality and distribution of resources. PMID:26943127

  15. Small population size and extremely low levels of genetic diversity in island populations of the platypus, Ornithorhynchus anatinus

    PubMed Central

    Furlan, Elise; Stoklosa, J; Griffiths, J; Gust, N; Ellis, R; Huggins, R M; Weeks, A R

    2012-01-01

    Genetic diversity generally underpins population resilience and persistence. Reductions in population size and absence of gene flow can lead to reductions in genetic diversity, reproductive fitness, and a limited ability to adapt to environmental change increasing the risk of extinction. Island populations are typically small and isolated, and as a result, inbreeding and reduced genetic diversity elevate their extinction risk. Two island populations of the platypus, Ornithorhynchus anatinus, exist; a naturally occurring population on King Island in Bass Strait and a recently introduced population on Kangaroo Island off the coast of South Australia. Here we assessed the genetic diversity within these two island populations and contrasted these patterns with genetic diversity estimates in areas from which the populations are likely to have been founded. On Kangaroo Island, we also modeled live capture data to determine estimates of population size. Levels of genetic diversity in King Island platypuses are perilously low, with eight of 13 microsatellite loci fixed, likely reflecting their small population size and prolonged isolation. Estimates of heterozygosity detected by microsatellites (HE= 0.032) are among the lowest level of genetic diversity recorded by this method in a naturally outbreeding vertebrate population. In contrast, estimates of genetic diversity on Kangaroo Island are somewhat higher. However, estimates of small population size and the limited founders combined with genetic isolation are likely to lead to further losses of genetic diversity through time for the Kangaroo Island platypus population. Implications for the future of these and similarly isolated or genetically depauperate populations are discussed. PMID:22837830

  16. [Alimentation dependent health disorders among adult population of Bashkortostan Republic and their relation with nutritional traits].

    PubMed

    Takaev, R M; Kondrova, N S; Baĭkina, I M; Larionova, T K

    2008-01-01

    The authors demonstrated relationship between alimentation dependent diseases among adult population of the Republic and nutritional traits of the population, defined major directions of program to optimize nutrition of the population.

  17. Predictors of Septic Arthritis in the Adult Population.

    PubMed

    Borzio, Robert; Mulchandani, Neil; Pivec, Robert; Kapadia, Bhaveen H; Leven, Dante; Harwin, Steven F; Urban, William P

    2016-07-01

    Septic arthritis is a devastating condition; well-established criteria for diagnosis exist in the pediatric population, but not for adults. This study evaluated patient factors and laboratory parameters that may be associated with the diagnosis of septic arthritis in adults. A total of 458 knee aspirates for suspected septic arthritis were evaluated with serum and synovial leukocyte counts and differentials as well as Kocher criteria for pediatric septic arthritis. Twenty-two patients (4.8%) had septic arthritis confirmed by a positive synovial fluid culture. Erythrocyte sedimentation rate (ESR) and serum white blood cell (WBC) counts were not statistically different between the 2 groups, with 64% of septic arthritis patients having a normal serum WBC count and 77% being afebrile. Mean synovial fluid WBC count was 26,758 cells/µL and 70,581 cells/µL in the nonseptic and septic groups, respectively. The likelihood ratio for a synovial fluid WBC count greater than 65,000 cells/µL was 2.8 (95% confidence interval, 1.2-6.7). Evaluation receiver operating characteristic curves using synovial WBC counts resulted in a significant area under the curve of 0.66 (P=.02). To achieve 90% specificity, a WBC cutoff of 64,000 cells/µL was required with a corresponding sensitivity of 40%. There was no significant difference in the synovial cell differential of 80% vs 90% in diagnosing infection. Synovial fluid WBC count greater than 64,000 cells/µL yielded the optimal combination of sensitivity and specificity. Polymorphonuclear leukocytes, ESR, serum WBC count, fever, and weight-bearing status were not significant predictors of septic arthritis. This study demonstrates the limited utility of Kocher criteria in the adult population and the importance of synovial leukocyte counts. [Orthopedics. 2016; 39(4):e657-e663.]. PMID:27286047

  18. Predictors of Septic Arthritis in the Adult Population.

    PubMed

    Borzio, Robert; Mulchandani, Neil; Pivec, Robert; Kapadia, Bhaveen H; Leven, Dante; Harwin, Steven F; Urban, William P

    2016-07-01

    Septic arthritis is a devastating condition; well-established criteria for diagnosis exist in the pediatric population, but not for adults. This study evaluated patient factors and laboratory parameters that may be associated with the diagnosis of septic arthritis in adults. A total of 458 knee aspirates for suspected septic arthritis were evaluated with serum and synovial leukocyte counts and differentials as well as Kocher criteria for pediatric septic arthritis. Twenty-two patients (4.8%) had septic arthritis confirmed by a positive synovial fluid culture. Erythrocyte sedimentation rate (ESR) and serum white blood cell (WBC) counts were not statistically different between the 2 groups, with 64% of septic arthritis patients having a normal serum WBC count and 77% being afebrile. Mean synovial fluid WBC count was 26,758 cells/µL and 70,581 cells/µL in the nonseptic and septic groups, respectively. The likelihood ratio for a synovial fluid WBC count greater than 65,000 cells/µL was 2.8 (95% confidence interval, 1.2-6.7). Evaluation receiver operating characteristic curves using synovial WBC counts resulted in a significant area under the curve of 0.66 (P=.02). To achieve 90% specificity, a WBC cutoff of 64,000 cells/µL was required with a corresponding sensitivity of 40%. There was no significant difference in the synovial cell differential of 80% vs 90% in diagnosing infection. Synovial fluid WBC count greater than 64,000 cells/µL yielded the optimal combination of sensitivity and specificity. Polymorphonuclear leukocytes, ESR, serum WBC count, fever, and weight-bearing status were not significant predictors of septic arthritis. This study demonstrates the limited utility of Kocher criteria in the adult population and the importance of synovial leukocyte counts. [Orthopedics. 2016; 39(4):e657-e663.].

  19. Four types of interference competition and their impacts on the ecology and evolution of size-structured populations and communities.

    PubMed

    Zhang, Lai; Andersen, Ken H; Dieckmann, Ulf; Brännström, Åke

    2015-09-01

    We investigate how four types of interference competition - which alternatively affect foraging, metabolism, survival, and reproduction - impact the ecology and evolution of size-structured populations. Even though all four types of interference competition reduce population biomass, interference competition at intermediate intensity sometimes significantly increases the abundance of adult individuals and the population׳s reproduction rate. We find that foraging and metabolic interference evolutionarily favor smaller maturation size when interference is weak and larger maturation size when interference is strong. The evolutionary response to survival interference and reproductive interference is always larger maturation size. We also investigate how the four types of interference competition impact the evolutionary dynamics and resultant diversity and trophic structure of size-structured communities. Like other types of trait-mediated competition, all four types of interference competition can induce disruptive selection and thus promote initial diversification. Even though foraging interference and reproductive interference are more potent in promoting initial diversification, they catalyze the formation of diverse communities with complex trophic structure only at high levels of interference intensity. By contrast, survival interference does so already at intermediate levels, while reproductive interference can only support relatively smaller communities with simpler trophic structure. Taken together, our results show how the type and intensity of interference competition jointly affect coexistence patterns in structured population models.

  20. Sex change and effective population size: implications for population genetic studies in marine fish.

    PubMed

    Coscia, I; Chopelet, J; Waples, R S; Mann, B Q; Mariani, S

    2016-10-01

    Large variance in reproductive success is the primary factor that reduces effective population size (Ne) in natural populations. In sequentially hermaphroditic (sex-changing) fish, the sex ratio is typically skewed and biased towards the 'first' sex, while reproductive success increases considerably after sex change. Therefore, sex-changing fish populations are theoretically expected to have lower Ne than gonochorists (separate sexes), assuming all other parameters are essentially equal. In this study, we estimate Ne from genetic data collected from two ecologically similar species living along the eastern coast of South Africa: one gonochoristic, the 'santer' sea bream Cheimerius nufar, and one protogynous (female-first) sex changer, the 'slinger' sea bream Chrysoblephus puniceus. For both species, no evidence of genetic structuring, nor significant variation in genetic diversity, was found in the study area. Estimates of contemporary Ne were significantly lower in the protogynous species, but the same pattern was not apparent over historical timescales. Overall, our results show that sequential hermaphroditism may affect Ne differently over varying time frames, and that demographic signatures inferred from genetic markers with different inheritance modes also need to be interpreted cautiously, in relation to sex-changing life histories.

  1. Sex change and effective population size: implications for population genetic studies in marine fish.

    PubMed

    Coscia, I; Chopelet, J; Waples, R S; Mann, B Q; Mariani, S

    2016-10-01

    Large variance in reproductive success is the primary factor that reduces effective population size (Ne) in natural populations. In sequentially hermaphroditic (sex-changing) fish, the sex ratio is typically skewed and biased towards the 'first' sex, while reproductive success increases considerably after sex change. Therefore, sex-changing fish populations are theoretically expected to have lower Ne than gonochorists (separate sexes), assuming all other parameters are essentially equal. In this study, we estimate Ne from genetic data collected from two ecologically similar species living along the eastern coast of South Africa: one gonochoristic, the 'santer' sea bream Cheimerius nufar, and one protogynous (female-first) sex changer, the 'slinger' sea bream Chrysoblephus puniceus. For both species, no evidence of genetic structuring, nor significant variation in genetic diversity, was found in the study area. Estimates of contemporary Ne were significantly lower in the protogynous species, but the same pattern was not apparent over historical timescales. Overall, our results show that sequential hermaphroditism may affect Ne differently over varying time frames, and that demographic signatures inferred from genetic markers with different inheritance modes also need to be interpreted cautiously, in relation to sex-changing life histories. PMID:27507184

  2. Physiological, Behavioral and Maternal Factors That Contribute to Size Variation in Larval Amphibian Populations

    PubMed Central

    Warne, Robin W.; Kardon, Adam; Crespi, Erica J.

    2013-01-01

    Size variance among similarly aged individuals within populations is a pattern common to many organisms that is a result of interactions between intrinsic and extrinsic traits of individuals. While genetic and maternal effects, as well as physiological and behavioral traits have been shown to contribute to size variation in animal populations, teasing apart the influence of such factors on individual growth rates remain a challenge. Furthermore, tracing the effects of these interactions across life stages and in shaping adult phenotypes also requires further exploration. In this study we investigated the relationship between genetics, hatching patterns, behaviors, neuroendocrine stress axis activity and variance in growth and metamorphosis among same-aged larval amphibians. Through parallel experiments we found that in the absence of conspecific interactions, hatch time and to a lesser extent egg clutch identity (i.e. genetics and maternal effects) influenced the propensity for growth and development in individual tadpoles and determined metamorphic traits. Within experimental groups we found that variance in growth rates was associated with size-dependent foraging behaviors and responses to food restriction. We also found an inverse relationship between glucocorticoid (GC) hormone levels and body mass and developmental stage among group-reared tadpoles, which suggests that GC expression plays a role in regulating differing within-population growth trajectories in response to density-dependent conditions. Taken together these findings suggest that factors that influence hatching conditions can have long-term effects on growth and development. These results also raise compelling questions regarding the extent to which maternal and genetic factors influence physiological and behavioral profiles in amphibians. PMID:24143188

  3. Founding population size of an aquatic invasive species

    USGS Publications Warehouse

    Kalinowski, Steven T.; Muhlfeld, Clint C.; Guy, Christopher S.; Benjamin Cox,

    2010-01-01

    Non-native species of fish threaten native fishes throughout North America, and in the Rocky Mountains, introduced populations of lake trout threaten native populations of bull trout. Effective management of lake trout and other exotic species require understanding the dynamics of invasion in order to either suppress non-native populations or to prevent their spread. In this study, we used microsatellite genetic data to estimate the number of lake trout that invaded a population of bull trout in Swan Lake, MT. Examination of genetic diversity and allele frequencies within the Swan Lake populations showed that most of the genes in the lake trout population are descended from two founders. This emphasizes the importance of preventing even a few lake trout from colonizing new territory.

  4. The prevalence of periodontal diseases among adult population in Georgia.

    PubMed

    Tsitaishvili, L; Margvelashvili, M; Kalandadze, M; Margvelashvili, V

    2014-09-01

    The present research was conducted to estimate the prevalence of periodontal diseases in the adult population of Georgia, to study the peculiarity of their distribution within population in different regions of the country. The survey was carried out based on cluster- stratified method derived by WHO. 2370 adults including 1289 women and 1081 men distributed in 4 age groups: I - 20-34, II - 35-44, III - 45-64, IV - 65+ the residents of the city, town and village in 9 regions of Georgia and the capital Tbilisi were examined. The assessment of periodontal status and oral hygiene was based on WHO-'s recommendation. (WHO 1997 '˜Oral Health Assessment Form') Examination was done under good natural light using a mouth mirror and a periodontal index (CPI) probe for measurements of periodontal pockets depth. Questionnaires comprised questions for revealing the following risk factors: social status and family income, existence of common diseases, people'S attitude towards oral hygiene(tooth brushing, using dental floss, mouth rinsing) acceptability of dental service, sugar consumption rate, tobacco use, consumption of dairy products. The reliable statistical data received from the study relieved high prevalence of periodontal diseases in all regions: in Achara - 71.7, Mtskheta-Mtianeti - 70.8%, Imereti - 64.9%, Qvemo Qartli - 61.6%, Tbilisi - 61.8% and Shida Qartli - 60.5%, Guria - 55.9%, Samtskhe-Javakheti - 56.0%, Kakheti - 59.1%, Samegrelo - 55.2%. Despite the variability of risk factors high prevalence of inflammatory periodontal diseases in regions of Georgia was related to more extent to the low educational medical background, less dental acceptability due to not very positive attitude towards dental service and oral hygiene skills though financial problems also played substantial role. The study confirmed that periodontal diseases represent an actual problem in Georgia and need caring out serious preventive measures to enhance peoples' referral to dental service and

  5. Young adults' trajectories of Ecstasy use: a population based study.

    PubMed

    Smirnov, Andrew; Najman, Jake M; Hayatbakhsh, Reza; Plotnikova, Maria; Wells, Helene; Legosz, Margot; Kemp, Robert

    2013-11-01

    Young adults' Ecstasy use trajectories have important implications for individual and population-level consequences of Ecstasy use, but little relevant research has been conducted. This study prospectively examines Ecstasy trajectories in a population-based sample. Data are from the Natural History Study of Drug Use, a retrospective/prospective cohort study conducted in Australia. Population screening identified a probability sample of Ecstasy users aged 19-23 years. Complete data for 30 months of follow-up, comprising 4 time intervals, were available for 297 participants (88.4% of sample). Trajectories were derived using cluster analysis based on recent Ecstasy use at each interval. Trajectory predictors were examined using a generalized ordered logit model and included Ecstasy dependence (World Mental Health Composite International Diagnostic Instrument), psychological distress (Hospital Anxiety Depression Scale), aggression (Young Adult Self Report) and contextual factors (e.g. attendance at electronic/dance music events). Three Ecstasy trajectories were identified (low, intermediate and high use). At its peak, the high-use trajectory involved 1-2 days Ecstasy use per week. Decreasing frequency of use was observed for intermediate and high-use trajectories from 12 months, independently of market factors. Intermediate and high-use trajectory membership was predicted by past Ecstasy consumption (>70 pills) and attendance at electronic/dance music events. High-use trajectory members were unlikely to have used Ecstasy for more than 3 years and tended to report consistently positive subjective effects at baseline. Given the social context and temporal course of Ecstasy use, Ecstasy trajectories might be better understood in terms of instrumental rather than addictive drug use patterns.

  6. The prevalence of periodontal diseases among adult population in Georgia.

    PubMed

    Tsitaishvili, L; Margvelashvili, M; Kalandadze, M; Margvelashvili, V

    2014-09-01

    The present research was conducted to estimate the prevalence of periodontal diseases in the adult population of Georgia, to study the peculiarity of their distribution within population in different regions of the country. The survey was carried out based on cluster- stratified method derived by WHO. 2370 adults including 1289 women and 1081 men distributed in 4 age groups: I - 20-34, II - 35-44, III - 45-64, IV - 65+ the residents of the city, town and village in 9 regions of Georgia and the capital Tbilisi were examined. The assessment of periodontal status and oral hygiene was based on WHO-'s recommendation. (WHO 1997 '˜Oral Health Assessment Form') Examination was done under good natural light using a mouth mirror and a periodontal index (CPI) probe for measurements of periodontal pockets depth. Questionnaires comprised questions for revealing the following risk factors: social status and family income, existence of common diseases, people'S attitude towards oral hygiene(tooth brushing, using dental floss, mouth rinsing) acceptability of dental service, sugar consumption rate, tobacco use, consumption of dairy products. The reliable statistical data received from the study relieved high prevalence of periodontal diseases in all regions: in Achara - 71.7, Mtskheta-Mtianeti - 70.8%, Imereti - 64.9%, Qvemo Qartli - 61.6%, Tbilisi - 61.8% and Shida Qartli - 60.5%, Guria - 55.9%, Samtskhe-Javakheti - 56.0%, Kakheti - 59.1%, Samegrelo - 55.2%. Despite the variability of risk factors high prevalence of inflammatory periodontal diseases in regions of Georgia was related to more extent to the low educational medical background, less dental acceptability due to not very positive attitude towards dental service and oral hygiene skills though financial problems also played substantial role. The study confirmed that periodontal diseases represent an actual problem in Georgia and need caring out serious preventive measures to enhance peoples' referral to dental service and

  7. Young adults' trajectories of Ecstasy use: a population based study.

    PubMed

    Smirnov, Andrew; Najman, Jake M; Hayatbakhsh, Reza; Plotnikova, Maria; Wells, Helene; Legosz, Margot; Kemp, Robert

    2013-11-01

    Young adults' Ecstasy use trajectories have important implications for individual and population-level consequences of Ecstasy use, but little relevant research has been conducted. This study prospectively examines Ecstasy trajectories in a population-based sample. Data are from the Natural History Study of Drug Use, a retrospective/prospective cohort study conducted in Australia. Population screening identified a probability sample of Ecstasy users aged 19-23 years. Complete data for 30 months of follow-up, comprising 4 time intervals, were available for 297 participants (88.4% of sample). Trajectories were derived using cluster analysis based on recent Ecstasy use at each interval. Trajectory predictors were examined using a generalized ordered logit model and included Ecstasy dependence (World Mental Health Composite International Diagnostic Instrument), psychological distress (Hospital Anxiety Depression Scale), aggression (Young Adult Self Report) and contextual factors (e.g. attendance at electronic/dance music events). Three Ecstasy trajectories were identified (low, intermediate and high use). At its peak, the high-use trajectory involved 1-2 days Ecstasy use per week. Decreasing frequency of use was observed for intermediate and high-use trajectories from 12 months, independently of market factors. Intermediate and high-use trajectory membership was predicted by past Ecstasy consumption (>70 pills) and attendance at electronic/dance music events. High-use trajectory members were unlikely to have used Ecstasy for more than 3 years and tended to report consistently positive subjective effects at baseline. Given the social context and temporal course of Ecstasy use, Ecstasy trajectories might be better understood in terms of instrumental rather than addictive drug use patterns. PMID:23899430

  8. Secular trends in reported portion size of food and beverages consumed by Irish adults.

    PubMed

    O'Brien, Sinead A; Livingstone, M Barbara E; McNulty, Breige A; Lyons, Jacqueline; Walton, Janette; Flynn, Albert; Segurado, Ricardo; Dean, Moira; Spence, Michelle; McCaffrey, Tracy A; Pourshahidi, L Kirsty; Nugent, Anne P; Gibney, Eileen R

    2015-04-14

    The present analysis aimed to investigate the changes in the reported portion sizes (PS) of foods and beverages commonly consumed by Irish adults (18-64 years) from the North South Ireland Food Consumption Survey (NSIFCS) (1997-2001) and the National Adult Nutrition Survey (NANS) (2008-10). Food PS, which are defined as the weight of food (g) consumed per eating occasion, were calculated for comparable foods and beverages in two nationally representative cross-sectional Irish food consumption surveys and were published in NSIFCS and NANS. Repeated measure mixed model analysis compared reported food PS at the total population level as well as subdivided by sex, age, BMI and social class. A total of thirteen commonly consumed foods were examined. The analysis demonstrated that PS significantly increased for five foods ('white sliced bread', 'brown/wholemeal breads', 'all meat, cooked', 'poultry, roasted' and 'milk'), significantly decreased for three ('potatoes', 'chips/wedges' and 'ham, sliced') and did not significantly change for five foods ('processed potato products', 'bacon/ham', 'cheese', 'yogurt' and 'butter/spreads') between the NSIFCS and the NANS. The present study demonstrates that there was considerable variation in the trends in reported food PS over this period. PMID:25789856

  9. Effects of spatial structure of population size on the population dynamics of barnacles across their elevational range.

    PubMed

    Fukaya, Keiichi; Okuda, Takehiro; Nakaoka, Masahiro; Noda, Takashi

    2014-11-01

    Explanations for why population dynamics vary across the range of a species reflect two contrasting hypotheses: (i) temporal variability of populations is larger in the centre of the range compared to the margins because overcompensatory density dependence destabilizes population dynamics and (ii) population variability is larger near the margins, where populations are more susceptible to environmental fluctuations. In both of these hypotheses, positions within the range are assumed to affect population variability. In contrast, the fact that population variability is often related to mean population size implies that the spatial structure of the population size within the range of a species may also be a useful predictor of the spatial variation in temporal variability of population size over the range of the species. To explore how population temporal variability varies spatially and the underlying processes responsible for the spatial variation, we focused on the intertidal barnacle Chthamalus dalli and examined differences in its population dynamics along the tidal levels it inhabits. Changes in coverage of barnacle populations were monitored for 10.5 years at 25 plots spanning the elevational range of this species. Data were analysed by fitting a population dynamics model to estimate the effects of density-dependent and density-independent processes on population growth. We also examined the temporal mean-variance relationship of population size with parameters estimated from the population dynamics model. We found that the relative variability of populations tended to increase from the centre of the elevational range towards the margins because of an increase in the magnitude of stochastic fluctuations of growth rates. Thus, our results supported hypothesis (2). We also found that spatial variations in temporal population variability were well characterized by Taylor's power law, the relative population variability being inversely related to the mean

  10. Influence of Population Density on Offspring Number and Size in Burying Beetles

    ERIC Educational Resources Information Center

    Rauter, Claudia M.

    2010-01-01

    This laboratory exercise investigates the influence of population density on offspring number and size in burying beetles. Students test the theoretical predictions that brood size declines and offspring size increases when competition over resources becomes stronger with increasing population density. Students design the experiment, collect and…

  11. Body size distributions of the pale grass blue butterfly in Japan: Size rules and the status of the Fukushima population.

    PubMed

    Taira, Wataru; Iwasaki, Mayo; Otaki, Joji M

    2015-07-22

    The body size of the pale grass blue butterfly, Zizeeria maha, has been used as an environmental indicator of radioactive pollution caused by the Fukushima nuclear accident. However, geographical and temporal size distributions in Japan and temperature effects on size have not been established in this species. Here, we examined the geographical, temporal, and temperature-dependent changes of the forewing size of Z. maha argia in Japan. Butterflies collected in 2012 and 2013 from multiple prefectures throughout Japan demonstrated an inverse relationship of latitude and forewing size, which is the reverse of Bergmann's cline. The Fukushima population was significantly larger than the Aomori and Miyagi populations and exhibited no difference from most of the other prefectural populations. When monitored at a single geographic locality every other month, forewing sizes were the largest in April and the smallest in August. Rearing larvae at a constant temperature demonstrated that forewing size followed the temperature-size rule. Therefore, the converse Bergmann's rule and the temperature-size rule coexist in this multivoltine species. Our study establishes this species as a useful environmental indicator and supports the idea that the size reduction observed only in Fukushima Prefecture in 2011 was caused by the environmental stress of radioactive pollution.

  12. Body size distributions of the pale grass blue butterfly in Japan: Size rules and the status of the Fukushima population

    NASA Astrophysics Data System (ADS)

    Taira, Wataru; Iwasaki, Mayo; Otaki, Joji M.

    2015-07-01

    The body size of the pale grass blue butterfly, Zizeeria maha, has been used as an environmental indicator of radioactive pollution caused by the Fukushima nuclear accident. However, geographical and temporal size distributions in Japan and temperature effects on size have not been established in this species. Here, we examined the geographical, temporal, and temperature-dependent changes of the forewing size of Z. maha argia in Japan. Butterflies collected in 2012 and 2013 from multiple prefectures throughout Japan demonstrated an inverse relationship of latitude and forewing size, which is the reverse of Bergmann’s cline. The Fukushima population was significantly larger than the Aomori and Miyagi populations and exhibited no difference from most of the other prefectural populations. When monitored at a single geographic locality every other month, forewing sizes were the largest in April and the smallest in August. Rearing larvae at a constant temperature demonstrated that forewing size followed the temperature-size rule. Therefore, the converse Bergmann’s rule and the temperature-size rule coexist in this multivoltine species. Our study establishes this species as a useful environmental indicator and supports the idea that the size reduction observed only in Fukushima Prefecture in 2011 was caused by the environmental stress of radioactive pollution.

  13. Body size distributions of the pale grass blue butterfly in Japan: Size rules and the status of the Fukushima population

    PubMed Central

    Taira, Wataru; Iwasaki, Mayo; Otaki, Joji M.

    2015-01-01

    The body size of the pale grass blue butterfly, Zizeeria maha, has been used as an environmental indicator of radioactive pollution caused by the Fukushima nuclear accident. However, geographical and temporal size distributions in Japan and temperature effects on size have not been established in this species. Here, we examined the geographical, temporal, and temperature-dependent changes of the forewing size of Z. maha argia in Japan. Butterflies collected in 2012 and 2013 from multiple prefectures throughout Japan demonstrated an inverse relationship of latitude and forewing size, which is the reverse of Bergmann’s cline. The Fukushima population was significantly larger than the Aomori and Miyagi populations and exhibited no difference from most of the other prefectural populations. When monitored at a single geographic locality every other month, forewing sizes were the largest in April and the smallest in August. Rearing larvae at a constant temperature demonstrated that forewing size followed the temperature-size rule. Therefore, the converse Bergmann’s rule and the temperature-size rule coexist in this multivoltine species. Our study establishes this species as a useful environmental indicator and supports the idea that the size reduction observed only in Fukushima Prefecture in 2011 was caused by the environmental stress of radioactive pollution. PMID:26197998

  14. Body size distributions of the pale grass blue butterfly in Japan: Size rules and the status of the Fukushima population.

    PubMed

    Taira, Wataru; Iwasaki, Mayo; Otaki, Joji M

    2015-01-01

    The body size of the pale grass blue butterfly, Zizeeria maha, has been used as an environmental indicator of radioactive pollution caused by the Fukushima nuclear accident. However, geographical and temporal size distributions in Japan and temperature effects on size have not been established in this species. Here, we examined the geographical, temporal, and temperature-dependent changes of the forewing size of Z. maha argia in Japan. Butterflies collected in 2012 and 2013 from multiple prefectures throughout Japan demonstrated an inverse relationship of latitude and forewing size, which is the reverse of Bergmann's cline. The Fukushima population was significantly larger than the Aomori and Miyagi populations and exhibited no difference from most of the other prefectural populations. When monitored at a single geographic locality every other month, forewing sizes were the largest in April and the smallest in August. Rearing larvae at a constant temperature demonstrated that forewing size followed the temperature-size rule. Therefore, the converse Bergmann's rule and the temperature-size rule coexist in this multivoltine species. Our study establishes this species as a useful environmental indicator and supports the idea that the size reduction observed only in Fukushima Prefecture in 2011 was caused by the environmental stress of radioactive pollution. PMID:26197998

  15. Age and Time Population Differences: Young Adults, Gen Xers, and Millennials

    ERIC Educational Resources Information Center

    Menard, Lauren A.

    2013-01-01

    Age and Time disparities in young adult research populations are common because young adults are defined by varying age spans; members of Generation X and Millennial generations may both be considered young adults; study years vary, affecting populations; and qualitative methods with limited age/year samples are frequently utilized. The current…

  16. Antarctic krill population genomics: apparent panmixia, but genome complexity and large population size muddy the water.

    PubMed

    Deagle, Bruce E; Faux, Cassandra; Kawaguchi, So; Meyer, Bettina; Jarman, Simon N

    2015-10-01

    Antarctic krill (Euphausia superba; hereafter krill) are an incredibly abundant pelagic crustacean which has a wide, but patchy, distribution in the Southern Ocean. Several studies have examined the potential for population genetic structuring in krill, but DNA-based analyses have focused on a limited number of markers and have covered only part of their circum-Antarctic range. We used mitochondrial DNA and restriction site-associated DNA sequencing (RAD-seq) to investigate genetic differences between krill from five sites, including two from East Antarctica. Our mtDNA results show no discernible genetic structuring between sites separated by thousands of kilometres, which is consistent with previous studies. Using standard RAD-seq methodology, we obtained over a billion sequences from >140 krill, and thousands of variable nucleotides were identified at hundreds of loci. However, downstream analysis found that markers with sufficient coverage were primarily from multicopy genomic regions. Careful examination of these data highlights the complexity of the RAD-seq approach in organisms with very large genomes. To characterize the multicopy markers, we recorded sequence counts from variable nucleotide sites rather than the derived genotypes; we also examined a small number of manually curated genotypes. Although these analyses effectively fingerprinted individuals, and uncovered a minor laboratory batch effect, no population structuring was observed. Overall, our results are consistent with panmixia of krill throughout their distribution. This result may indicate ongoing gene flow. However, krill's enormous population size creates substantial panmictic inertia, so genetic differentiation may not occur on an ecologically relevant timescale even if demographically separate populations exist.

  17. Both population size and patch quality affect local extinctions and colonizations.

    PubMed

    Franzén, Markus; Nilsson, Sven G

    2010-01-01

    Currently, the habitat of many species is fragmented, resulting in small local populations with individuals occasionally dispersing between the remaining habitat patches. In a solitary bee metapopulation, extinction probability was related to both local bee population sizes and pollen resources measured as host plant population size. Patch size, on the other hand, had no additional predictive power. The turnover rate of local bee populations in 63 habitat patches over 4 years was high, with 72 extinction events and 31 colonization events, but the pollen plant population was stable with no extinctions or colonizations. Both pollen resources and bee populations had strong and independent effects on extinction probability, but connectivity was not of importance. Colonizations occurred more frequently within larger host plant populations. For metapopulation survival of the bee, large pollen plant populations are essential, independent of current bee population size.

  18. Trends in diet quality among adolescents, adults and older adults: A population-based study.

    PubMed

    Andrade, Samantha Caesar de; Previdelli, Ágatha Nogueira; Cesar, Chester Luiz Galvão; Marchioni, Dirce Maria Lobo; Fisberg, Regina Mara

    2016-12-01

    This study aimed to monitor diet quality and associated factors in adolescents, adults and older adults from the city of São Paulo, Brazil. We conducted a cross-sectional population-based study involving 2376 individuals surveyed in 2003, and 1662 individuals in 2008 (Health Survey of São Paulo, ISA-Capital). Participants were of both sexes and aged 12 to 19 years old (adolescents), 20 to 59 years old (adults) and 60 years old or over (older adults). Food intake was assessed using the 24-h dietary recall method while diet quality was determined by the Brazilian Healthy Eating Index (BHEI-R). The prevalence of descriptive variables for 2003 and 2008 was compared adopting a confidence interval of 95%. The means of total BHEI-R score and its components for 2003 and 2008 were compared for each age group. Associations between the BHEI-R and independent variables were evaluated for each survey year using multiple linear regression analysis. Results showed that the mean BHEI-R increased (54.9 vs. 56.4 points) over the five-year period. However, the age group evaluation showed a deterioration in diet quality of adolescents, influenced by a decrease in scores for dark-green and orange vegetables and legumes, total grains, oils and SoFAAS (solid fat, alcohol and added sugar) components. In the 2008 survey, adults had a higher BHEI-R score, by 6.1 points on average, compared to adolescents. Compared to older adults, this difference was 10.7 points. The diet quality remains a concern, especially among adolescents, that had the worst results compared to the other age groups. PMID:27547722

  19. Eco-evolutionary dynamics: fluctuations in population growth rate reduce effective population size in chinook salmon.

    PubMed

    Waples, Robin S; Jensen, David W; McClure, Michelle

    2010-03-01

    We empirically assess the relationship between population growth rate (lambda, a parameter central to ecology) and effective population size (N(e), a key parameter in evolutionary biology). Recent theoretical and numerical studies indicate that in semelparous species with variable age at maturity (such as Pacific salmon, many monocarpic plants, and various other species), differences in mean reproductive success among individuals reproducing in different years leads to variation in lambda, and this in turn can reduce N(e). However, this phenomenon has received little empirical evaluation. We examined time series of abundance data for 56 populations of chinook salmon (Onchorhynchus tshawytscha) from the northwestern United States and compared N(e) (calculated from demographic data) with the total number of spawners each generation (NT). Important results include: (1) The mean multigenerational ratio N(e)/N(T) was 0.64 (median = 0.67), indicating that annual variation in lambda reduces effective population size in chinook salmon by an average of approximately 35%. These reductions are independent of, and in addition to, factors that reduce N(e) within individual cohorts (uneven sex ratio and greater-than-random variance in reproductive success). (2) The coefficient of variation of lambda was the most important factor associated with reductions in N(e), explaining up to two-thirds of the variance in N(e)/N(T). (3) Within individual generations, N(e) was lower when there was a negative correlation between annual N(i) and lambda, i.e., when relatively few breeders produced relatively high numbers of offspring. Our results thus highlight an important and little-studied eco-evolutionary trade-off: density-dependent compensation has generally favorable ecological consequences (promoting stability and long-term viability) but incurs an evolutionary cost (reducing N(e) because a few individuals make a disproportionate genetic contribution). (4) For chinook salmon, N(eH) (an

  20. Determining size and dispersion of minimum viable populations for land management planning and species conservation

    NASA Astrophysics Data System (ADS)

    Lehmkuhl, John F.

    1984-03-01

    The concept of minimum populations of wildlife and plants has only recently been discussed in the literature. Population genetics has emerged as a basic underlying criterion for determining minimum population size. This paper presents a genetic framework and procedure for determining minimum viable population size and dispersion strategies in the context of multiple-use land management planning. A procedure is presented for determining minimum population size based on maintenance of genetic heterozygosity and reduction of inbreeding. A minimum effective population size ( N e ) of 50 breeding animals is taken from the literature as the minimum shortterm size to keep inbreeding below 1% per generation. Steps in the procedure adjust N e to account for variance in progeny number, unequal sex ratios, overlapping generations, population fluctuations, and period of habitat/population constraint. The result is an approximate census number that falls within a range of effective population size of 50 500 individuals. This population range defines the time range of short- to long-term population fitness and evolutionary potential. The length of the term is a relative function of the species generation time. Two population dispersion strategies are proposed: core population and dispersed population.

  1. Population size is weakly related to quantitative genetic variation and trait differentiation in a stream fish.

    PubMed

    Wood, Jacquelyn L A; Tezel, Defne; Joyal, Destin; Fraser, Dylan J

    2015-09-01

    How population size influences quantitative genetic variation and differentiation among natural, fragmented populations remains unresolved. Small, isolated populations might occupy poor quality habitats and lose genetic variation more rapidly due to genetic drift than large populations. Genetic drift might furthermore overcome selection as population size decreases. Collectively, this might result in directional changes in additive genetic variation (VA ) and trait differentiation (QST ) from small to large population size. Alternatively, small populations might exhibit larger variation in VA and QST if habitat fragmentation increases variability in habitat types. We explored these alternatives by investigating VA and QST using nine fragmented populations of brook trout varying 50-fold in census size N (179-8416) and 10-fold in effective number of breeders, Nb (18-135). Across 15 traits, no evidence was found for consistent differences in VA and QST with population size and almost no evidence for increased variability of VA or QST estimates at small population size. This suggests that (i) small populations of some species may retain adaptive potential according to commonly adopted quantitative genetic measures and (ii) populations of varying sizes experience a variety of environmental conditions in nature, however extremely large studies are likely required before any firm conclusions can be made. PMID:26207947

  2. Birth weight, early life course BMI, and body size change: Chains of risk to adult inflammation?

    PubMed

    Goosby, Bridget J; Cheadle, Jacob E; McDade, Thomas

    2016-01-01

    This paper examines how body size changes over the early life course to predict high sensitivity C-reactive protein in a U.S. based sample. Using three waves of the National Longitudinal Study of Adolescent Health (Add Health), we test the chronic disease epidemiological models of fetal origins, sensitive periods, and chains of risk from birth into adulthood. Few studies link birth weight and changes in obesity status over adolescence and early adulthood to adult obesity and inflammation. Consistent with fetal origins and sensitive periods hypotheses, body size and obesity status at each developmental period, along with increasing body size between periods, are highly correlated with adult CRP. However, the predictive power of earlier life course periods is mediated by body size and body size change at later periods in a pattern consistent with the chains of risk model. Adult increases in obesity had effect sizes of nearly 0.3 sd, and effect sizes from overweight to the largest obesity categories were between 0.3 and 1 sd. There was also evidence that risk can be offset by weight loss, which suggests that interventions can reduce inflammation and cardiovascular risk, that females are more sensitive to body size changes, and that body size trajectories over the early life course account for African American- and Hispanic-white disparities in adult inflammation.

  3. Prevalence of voice quality deviations in the normal adult population.

    PubMed

    Brindle, B R; Morris, H L

    1979-11-01

    The purpose of this study was to determine the prevalence of voice quality deviations in a normal adult population. One-hundred twelve subjects, aged 17 to 80, read a short paragraph aloud into a high-fidelity tape recorder and completed a case history questionnaire. A group of 11 pretrained judges rated overall performance of each taped sample on a seven-point equal-appearing intervals scale, then designated those quality components which contributed toward deviant ratings. Eighty-two percent of the group received a mean severity rating lower than 1.99; 16% had a rating between 2.00 and 2.99; and 2% was assigned a mean rating higher than 3.00.

  4. Surface anatomy and anatomical planes in the adult turkish population.

    PubMed

    Uzun, C; Atman, E D; Ustuner, E; Mirjalili, S A; Oztuna, D; Esmer, T S

    2016-03-01

    Surface anatomy and anatomical planes are widely used in education and clinical practice. The planes are largely derived from cadaveric studies and their projections on the skin show discrepancies between and within anatomical reference textbooks. In this study, we reassessed the accuracy of common thoracic and abdominopelvic anatomical planes using computed tomography (CT) imaging in the live adult Turkish population. After patients with distorting pathologies had been excluded, CT images of 150 supine patients at the end tidal inspiration were analyzed. Sternal angle, transpyloric, subcostal, supracristal and pubic crest planes and their relationships to anatomical structures were established by dual consensus. The tracheal bifurcation, azygos vein/superior vena cava (SVC) junction and pulmonary bifurcation were usually below the sternal angle while the concavity of the aortic arch was generally within the plane. The tip of the tenth rib, the superior mesenteric artery and the portal vein were usually within the transpyloric plane while the renal hila and the fundus of the gallbladder were below it. The inferior mesenteric artery was below the subcostal plane and the aortic bifurcation was below the supracristal plane in most adults. Projectional surface anatomy is fundamental to medical education and clinical practice. Modern cross-sectional imaging techniques allow large groups of live patients to be examined. Classic textbook information regarding anatomy needs to be reviewed and updated using the data gathered from these recent studies, taking ethnic differences into consideration.

  5. Anthropometric data of adult wheelchair users for Mexican population.

    PubMed

    Lucero-Duarte, Karla; de la Vega-Bustillos, Enrique; López-Millán, Francisco; Soto-Félix, Selene

    2012-01-01

    The aim of the study was to obtain anthropometric data of adult wheelchair users at Mexico. This study count with 108 disabled people (56 men and 52 women) using the wheelchair and having the upper extremities sufficiently efficient to perform professional activities. The subjects were aged 18-60. From the measurements obtained, it can be said that in each of these measures was observed that men have larger dimensions than women, except for body depth, in which women had a slightly greater difference. When comparing the data in this study against other studies it shows that there is a significant difference between the averages of these studies. Similar results were obtained when comparing our data against data of standard population. Anthropometric data obtained through this study appear to be the only of this kind in Mexico and showed significant differences between measures of disabled persons and standard persons. the use of these data may be helpful for the proper design of workstations designed for use by adults who use.

  6. Population size and the nature of genetic load in Gentianella germanica.

    PubMed

    Paland, Susanne; Schmid, Bernhard

    2003-10-01

    Theory predicts a significant relationship between the size of a population and the magnitude and composition of its genetic load, but few natural populations have been investigated. We examined the magnitude of genetic load due to recessive deleterious alleles (GL) both segregating and fixed within Gentianella germanica populations of varying size by selfing and reciprocally crossing plants within and between natural populations according to a partial diallel design and by comparing the performance of the experimental progeny in a common-garden experiment. The results show that GL for total fitness in small populations (fewer than 200 plants) was mainly due to fixed recessive deleterious alleles, whereas GL for total fitness in larger populations (more than 200 plants) appeared to be mainly due to segregating deleterious recessive alleles. The total fitness of selfed plants increased with decreasing population size, indicating some purging of deleterious alleles associated with declining population sizes. The magnitudes of GL due to fixed deleterious alleles in small populations and segregating deleterious alleles in large populations, however, were overall similar, suggesting that purging selection was an insignificant force when compared to genetic drift in determining the magnitude of GL in small natural populations in this species. The results of this study highlight the importance of population size in determining the dynamics of genetic loads of natural populations and are overall in line with a large body of theoretical work indicating that small populations may face higher extinction risks due to the fixation and accumulation of deleterious alleles of small effect.

  7. An aerial sightability model for estimating ferruginous hawk population size

    USGS Publications Warehouse

    Ayers, L.W.; Anderson, S.H.

    1999-01-01

    Most raptor aerial survey projects have focused on numeric description of visibility bias without identifying the contributing factors or developing predictive models to account for imperfect detection rates. Our goal was to develop a sightability model for nesting ferruginous hawks (Buteo regalis) that could account for nests missed during aerial surveys and provide more accurate population estimates. Eighteen observers, all unfamiliar with nest locations in a known population, searched for nests within 300 m of flight transects via a Maule fixed-wing aircraft. Flight variables tested for their influence on nest-detection rates included aircraft speed, height, direction of travel, time of day, light condition, distance to nest, and observer experience level. Nest variables included status (active vs. inactive), condition (i.e., excellent, good, fair, poor, bad), substrate type, topography, and tree density. A multiple logistic regression model identified nest substrate type, distance to nest, and observer experience level as significant predictors of detection rates (P < 0.05). The overall model was significant (??26 = 124.4, P < 0.001, n = 255 nest observations), and the correct classification rate was 78.4%. During 2 validation surveys, observers saw 23.7% (14/59) and 36.5% (23/63) of the actual population. Sightability model predictions, with 90% confidence intervals, captured the true population in both tests. Our results indicate standardized aerial surveys, when used in conjunction with the predictive sightability model, can provide unbiased population estimates for nesting ferruginous hawks.

  8. Loss of microsatellite diversity and low effective population size in an overexploited population of New Zealand snapper (Pagrus auratus).

    PubMed

    Hauser, Lorenz; Adcock, Greg J; Smith, Peter J; Ramiréz, Julio H Bernal; Carvalho, Gary R

    2002-09-01

    Although the effects of overfishing on species diversity and abundance are well documented, threats to the genetic diversity of marine fish populations have so far been largely neglected. Indeed, there seems to be little cause for concern, as even "collapsed" stocks usually consist of several million individuals, whereas population genetics theory suggests that only very small populations suffer significant loss of genetic diversity. On the other hand, in many marine species the genetically effective population size (N(e)), which determines the genetic properties of a population, may be orders of magnitude smaller than the census population size (N). Here, microsatellite analyses of a time series of archived scales demonstrated a significant decline in genetic diversity in a New Zealand snapper population during its exploitation history. Effective population sizes estimated both from the decline in heterozygosity and from temporal fluctuations in allele frequency were five orders of magnitude smaller than census population sizes from fishery data. If such low N(e)/N ratios are commonplace in marine species, many exploited marine fish stocks may be in danger of losing genetic variability, potentially resulting in reduced adaptability, population persistence, and productivity.

  9. Genetic correlations between adults and larvae in a marine fish: potential effects of fishery selection on population replenishment

    PubMed Central

    Johnson, Darren W; Christie, Mark R; Moye, Jessica; Hixon, Mark A

    2011-01-01

    Correlated genetic responses have been hypothesized as important components of fishery-induced evolution, although predictive data from wild populations have been difficult to obtain. Here, we demonstrate substantial genetic correlations between a trait often subjected to fishery selection (adult body length) and traits that affect survival of larvae (length and swimming performance) in a wild population of a marine fish (bicolor damselfish, Stegastes partitus). Through both genetic covariance and size-dependent maternal effects, selection on adult size may cause a considerable, correlated response in larval traits. To quantify how variation in larval traits may affect survival, we introduce a flexible method that uses information from selection measurements to account for frequency dependence and estimate the relationship between phenotype and relative survival across a broad range of phenotypic values. Using this method, we synthesize studies of selective mortality on larval size for eight species of fish and show that variation in larval size may result in considerable variation in larval survival. We predict that observed rates of fishery selection on adult marine fishes may substantially reduce larval size and survival. The evolution of smaller larvae in response to fishery selection may therefore have substantial consequences for the viability of fished populations. PMID:25568010

  10. Estimating population size of Pygoscelid Penguins from TM data

    NASA Technical Reports Server (NTRS)

    Olson, Charles E., Jr.; Schwaller, Mathew R.; Dahmer, Paul A.

    1987-01-01

    An estimate was made toward a continent wide population of penguins. The results indicate that Thematic Mapper data can be used to identify penguin rookeries due to the unique reflectance properties of guano. Strong correlations exist between nesting populations and rookery area occupied by the birds. These correlations allow estimation of the number of nesting pairs in colonies. The success of remote sensing and biometric analyses leads one to believe that a continent wide estimate of penguin populations is possible based on a timely sample employing ground based and remote sensing techniques. Satellite remote sensing along the coastline may well locate previously undiscovered penguin nesting sites, or locate rookeries which have been assumed to exist for over a half century, but never located. Observations which found that penguins are one of the most sensitive elements in the complex of Southern Ocean ecosystems motivated this study.

  11. The effect of practical portion size measurement aids on the accuracy of portion size estimates made by young adults.

    PubMed

    Byrd-Bredbenner, C; Schwartz, J

    2004-08-01

    A barrier to controlling the amount of food consumed may be the difficulty consumers have in accurately estimating portion sizes. Although portion size measurement aids (PSMAs) can improve estimation accuracy, their bulk and/or cost tends to make them impractical for regular use. The purpose of this study was to investigate the effect on portion size estimation accuracy of two practical PSMAs: a 2-D PSMA (life size picture of tennis and golf balls) and 3-D PSMAs (tennis and golf balls). Young adults were randomly assigned to one of two groups and estimated the portion sizes of 36 foods divided into three equal sets. PSMAs were not used to estimate portion sizes in Food Set 1. Study group 1 (n = 57) used the 2-D PSMA and study group 2 (n = 56) used the 3-D PSMAs to estimate the portion sizes in Food Set 2. Neither group used PSMAs to estimate portion sizes in Food Set 3. Repeated measures anova indicated that both groups significantly improved estimation accuracy between Food Sets 1 and 2 and between Foods Sets 1 and 3. Thus, even short-term exposure to practical PSMAs may improve estimation accuracy and these improvements persist when the PSMA is no longer available. However, the accuracy rate for Food Set 2 was only about 60% indicating that a great deal of estimation error remains. PMID:15250844

  12. Prevalence of Dental Caries in Kosovar Adult Population

    PubMed Central

    Begzati, Agim; Kelmendi, Jeta; Ilijazi, Donika; Kqiku, Lumnije

    2016-01-01

    Objectives. The aim of this study was to assess the prevalence of dental caries in the Kosovar adult population. Materials and Methods. A cross-sectional study in Kosovo was conducted examining 9387 patients, aged 18 upwards, between January 2010 and December 2011. Clinical evaluation was done using WHO criteria for evaluation of dental health status and data collection. Results. The prevalence of caries for the whole study was 72.80%. The mean DMFT index was 9.61 (±5.12) in the 18–34-year age group, 11.6 (±6.42) in the 35–44-year age group, 13.68 (±8.12) among the 45–64-year age group, 17.98 (±9.81) in the 65–74-year age group, and 23.19 (±9.41) in the age group of 75+ years, respectively. A significant difference of mean DMFT and its each component was observed between the ages (P < 0.001). Conclusion. This study comes out with the significant levels of dental caries among young Kosovar population (18–34 years old). PMID:27516774

  13. Impact of minimum catch size on the population viability of Strombus gigas (Mesogastropoda: Strombidae) in Quintana Roo, Mexico.

    PubMed

    Peel, Joanne R; Mandujano, María del Carmen

    2014-12-01

    The queen conch Strombus gigas represents one of the most important fishery resources of the Caribbean but heavy fishing pressure has led to the depletion of stocks throughout the region, causing the inclusion of this species into CITES Appendix II and IUCN's Red-List. In Mexico, the queen conch is managed through a minimum fishing size of 200 mm shell length and a fishing quota which usually represents 50% of the adult biomass. The objectives of this study were to determine the intrinsic population growth rate of the queen conch population of Xel-Ha, Quintana Roo, Mexico, and to assess the effects of a regulated fishing impact, simulating the extraction of 50% adult biomass on the population density. We used three different minimum size criteria to demonstrate the effects of minimum catch size on the population density and discuss biological implications. Demographic data was obtained through capture-mark-recapture sampling, collecting all animals encountered during three hours, by three divers, at four different sampling sites of the Xel-Ha inlet. The conch population was sampled each month between 2005 and 2006, and bimonthly between 2006 and 2011, tagging a total of 8,292 animals. Shell length and lip thickness were determined for each individual. The average shell length for conch with formed lip in Xel-Ha was 209.39 ± 14.18 mm and the median 210 mm. Half of the sampled conch with lip ranged between 200 mm and 219 mm shell length. Assuming that the presence of the lip is an indicator for sexual maturity, it can be concluded that many animals may form their lip at greater shell lengths than 200 mm and ought to be considered immature. Estimation of relative adult abundance and densities varied greatly depending on the criteria employed for adult classification. When using a minimum fishing size of 200 mm shell length, between 26.2% and up to 54.8% of the population qualified as adults, which represented a simulated fishing impact of almost one third of the

  14. Impact of minimum catch size on the population viability of Strombus gigas (Mesogastropoda: Strombidae) in Quintana Roo, Mexico.

    PubMed

    Peel, Joanne R; Mandujano, María del Carmen

    2014-12-01

    The queen conch Strombus gigas represents one of the most important fishery resources of the Caribbean but heavy fishing pressure has led to the depletion of stocks throughout the region, causing the inclusion of this species into CITES Appendix II and IUCN's Red-List. In Mexico, the queen conch is managed through a minimum fishing size of 200 mm shell length and a fishing quota which usually represents 50% of the adult biomass. The objectives of this study were to determine the intrinsic population growth rate of the queen conch population of Xel-Ha, Quintana Roo, Mexico, and to assess the effects of a regulated fishing impact, simulating the extraction of 50% adult biomass on the population density. We used three different minimum size criteria to demonstrate the effects of minimum catch size on the population density and discuss biological implications. Demographic data was obtained through capture-mark-recapture sampling, collecting all animals encountered during three hours, by three divers, at four different sampling sites of the Xel-Ha inlet. The conch population was sampled each month between 2005 and 2006, and bimonthly between 2006 and 2011, tagging a total of 8,292 animals. Shell length and lip thickness were determined for each individual. The average shell length for conch with formed lip in Xel-Ha was 209.39 ± 14.18 mm and the median 210 mm. Half of the sampled conch with lip ranged between 200 mm and 219 mm shell length. Assuming that the presence of the lip is an indicator for sexual maturity, it can be concluded that many animals may form their lip at greater shell lengths than 200 mm and ought to be considered immature. Estimation of relative adult abundance and densities varied greatly depending on the criteria employed for adult classification. When using a minimum fishing size of 200 mm shell length, between 26.2% and up to 54.8% of the population qualified as adults, which represented a simulated fishing impact of almost one third of the

  15. Population size of snowy plovers breeding in North America

    USGS Publications Warehouse

    Thomas, Susan M.; Lyons, James E.; Andres, Brad A.; T-Smith, Elise Elliot; Palacios, Eduardo; Cavitt, John F.; Royle, J. Andrew; Fellows, Suzanne D.; Maty, Kendra; Howe, William H.; Mellink, Eric; Melvin, Stefani; Zimmerman, Tara

    2012-01-01

    Snowy Plovers (Charadrius nivosus) may be one of the rarest shorebirds in North America yet a comprehensive assessment of their abundance and distribution has not been completed. During 2007 and 2008, 557 discrete wetlands were surveyed and nine additional large wetland complexes sampled in México and the USA. From these surveys, a population of 23,555 (95% CI = 17,299 – 29,859) breeding Snowy Plovers was estimated. Combining the estimate with information from areas not surveyed, the total North American population was assessed at 25,869 (95% CI = 18,917 – 32,173). Approximately 42% of all breeding Snowy Plovers in North America resided at two sites (Great Salt Lake, Utah, and Salt Plains National Wildlife Refuge, Oklahoma), and 33% of all these were on wetlands in the Great Basin (including Great Salt Lake). Also, coastal habitats in central and southern Texas supported large numbers of breeding plovers. New breeding sites were discovered in interior deserts and highlands and along the Pacific coast of México; approximately 9% of the North American breeding population occurred in México. Because of uncertainties about effects of climate change and current stresses to breeding habitats, the species should be a management and conservation priority. Periodic monitoring should be undertaken at important sites to ensure high quality habitat is available to support the Snowy Plover population.

  16. Cohort Size and Migration in a West Indian Population.

    ERIC Educational Resources Information Center

    Brittain, Ann W.

    1990-01-01

    Data from St. Barthelemy (French West Indies) show that, for people born from 1878 to 1967, neither cohort size nor fluctuations in external demands for labor had a lasting effect on the probability of eventual migration. Emigration slowed only after development of local tourism brought prosperity to the island. (AF)

  17. Genetic effective size is three orders of magnitude smaller than adult census size in an abundant, Estuarine-dependent marine fish (Sciaenops ocellatus).

    PubMed

    Turner, Thomas F; Wares, John P; Gold, John R

    2002-11-01

    Using eight microsatellite loci and a variety of analytical methods, we estimated genetic effective size (N(e)) of an abundant and long-lived marine fish species, the red drum (Sciaenops ocellatus), in the northern Gulf of Mexico (Gulf). The ratio N(e)/N, where short-term variance N(e) was estimated via the temporal method from shifts in allele-frequency data over four cohorts and where N reflected a current estimate of adult census size in the northern Gulf, was approximately 0.001. In an idealized population, this ratio should approximate unity. The extraordinarily low value of N(e)/N appears to arise from high variance in individual reproductive success and perhaps more importantly from variance in productivity of critical spawning and nursery habitats located in spatially discrete bays and estuaries throughout the northern Gulf. An estimate of N(e) based on a coalescent approach, which measures long-term, inbreeding effective size, was four orders of magnitude lower than the estimate of current census size, suggesting that factors presently driving N(e)/N to low values among red drum in the northern Gulf may have operated similarly in the past. Models that predict N(e)/N exclusively from demographic and life-history features will seriously overestimate N(e) if variance in reproductive success and variance in productivity among spatially discrete demes is underestimated. Our results indicate that these variances, especially variance in productivity among demes, must be large for red drum. Moreover, our study indicates that vertebrate populations with enormous adult census numbers may still be at risk relative to decline and extinction from genetic factors.

  18. Genetic effective size is three orders of magnitude smaller than adult census size in an abundant, Estuarine-dependent marine fish (Sciaenops ocellatus).

    PubMed Central

    Turner, Thomas F; Wares, John P; Gold, John R

    2002-01-01

    Using eight microsatellite loci and a variety of analytical methods, we estimated genetic effective size (N(e)) of an abundant and long-lived marine fish species, the red drum (Sciaenops ocellatus), in the northern Gulf of Mexico (Gulf). The ratio N(e)/N, where short-term variance N(e) was estimated via the temporal method from shifts in allele-frequency data over four cohorts and where N reflected a current estimate of adult census size in the northern Gulf, was approximately 0.001. In an idealized population, this ratio should approximate unity. The extraordinarily low value of N(e)/N appears to arise from high variance in individual reproductive success and perhaps more importantly from variance in productivity of critical spawning and nursery habitats located in spatially discrete bays and estuaries throughout the northern Gulf. An estimate of N(e) based on a coalescent approach, which measures long-term, inbreeding effective size, was four orders of magnitude lower than the estimate of current census size, suggesting that factors presently driving N(e)/N to low values among red drum in the northern Gulf may have operated similarly in the past. Models that predict N(e)/N exclusively from demographic and life-history features will seriously overestimate N(e) if variance in reproductive success and variance in productivity among spatially discrete demes is underestimated. Our results indicate that these variances, especially variance in productivity among demes, must be large for red drum. Moreover, our study indicates that vertebrate populations with enormous adult census numbers may still be at risk relative to decline and extinction from genetic factors. PMID:12454077

  19. Potential environmental influences on variation in body size and sexual size dimorphism among Arizona populations of the western diamond-backed rattlesnake (Crotalus atrox)

    USGS Publications Warehouse

    Amarello, M.; Nowak, E.M.; Taylor, E.N.; Schuett, G.W.; Repp, R.A.; Rosen, P.C.; Hardy, D.L.

    2010-01-01

    Differences in resource availability and quality along environmental gradients are important influences contributing to intraspecific variation in body size, which influences numerous life-history traits. Here, we examined variation in body size and sexual size dimorphism (SSD) in relation to temperature, seasonality, and precipitation among 10 populations located throughout Arizona of the western diamond-backed rattlesnake (Crotalus atrox). Specifically, in our analyses we addressed the following questions: (i) Are adult males larger in cooler, wetter areas? (ii) Does female body size respond differently to environmental variation? (iii) Is seasonality a better predictor of body size variation? (iv) Is SSD positively correlated with increased resources? We demonstrate that male and female C. atrox are larger in body size in cooler (i.e., lower average annual maximum, minimum, and mean temperature) and wetter areas (i.e., higher average annual precipitation, more variable precipitation, and available surface water). Although SSD in C. atrox appeared to be more pronounced in cooler, wetter areas, this relationship did not achieve statistical significance. ?? 2010 Elsevier Ltd.

  20. The Relationship between the Proportional Size of the Special Education Population and Academic Achievement

    ERIC Educational Resources Information Center

    Harper, Patricia Kenner

    2013-01-01

    This investigation addressed the hypothesized effects of the proportional size of a district's special education population on the overall student achievement in selected school districts in Texas. The size of a district's special education population (independent variable) was compared to districts' achievement (dependent…

  1. Effect of reference population size and available ancestor genotypes on imputation of Mexican Holstein genotypes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of reference population size and the availability of information from genotyped ancestors on the accuracy of imputation of single nucleotide polymorphisms (SNPs) were investigated for Mexican Holstein cattle. Three scenarios for reference population size were examined: (1) a local popula...

  2. Noninvasive genetics provides insights into the population size and genetic diversity of an Amur tiger population in China.

    PubMed

    Wang, Dan; Hu, Yibo; Ma, Tianxiao; Nie, Yonggang; Xie, Yan; Wei, Fuwen

    2016-01-01

    Understanding population size and genetic diversity is critical for effective conservation of endangered species. The Amur tiger (Panthera tigris altaica) is the largest felid and a flagship species for wildlife conservation. Due to habitat loss and human activities, available habitat and population size are continuously shrinking. However, little is known about the true population size and genetic diversity of wild tiger populations in China. In this study, we collected 55 fecal samples and 1 hair sample to investigate the population size and genetic diversity of wild Amur tigers in Hunchun National Nature Reserve, Jilin Province, China. From the samples, we determined that 23 fecal samples and 1 hair sample were from 7 Amur tigers: 2 males, 4 females and 1 individual of unknown sex. Interestingly, 2 fecal samples that were presumed to be from tigers were from Amur leopards, highlighting the significant advantages of noninvasive genetics over traditional methods in studying rare and elusive animals. Analyses from this sample suggested that the genetic diversity of wild Amur tigers is much lower than that of Bengal tigers, consistent with previous findings. Furthermore, the genetic diversity of this Hunchun population in China was lower than that of the adjoining subpopulation in southwest Primorye Russia, likely due to sampling bias. Considering the small population size and relatively low genetic diversity, it is urgent to protect this endangered local subpopulation in China.

  3. Noninvasive genetics provides insights into the population size and genetic diversity of an Amur tiger population in China.

    PubMed

    Wang, Dan; Hu, Yibo; Ma, Tianxiao; Nie, Yonggang; Xie, Yan; Wei, Fuwen

    2016-01-01

    Understanding population size and genetic diversity is critical for effective conservation of endangered species. The Amur tiger (Panthera tigris altaica) is the largest felid and a flagship species for wildlife conservation. Due to habitat loss and human activities, available habitat and population size are continuously shrinking. However, little is known about the true population size and genetic diversity of wild tiger populations in China. In this study, we collected 55 fecal samples and 1 hair sample to investigate the population size and genetic diversity of wild Amur tigers in Hunchun National Nature Reserve, Jilin Province, China. From the samples, we determined that 23 fecal samples and 1 hair sample were from 7 Amur tigers: 2 males, 4 females and 1 individual of unknown sex. Interestingly, 2 fecal samples that were presumed to be from tigers were from Amur leopards, highlighting the significant advantages of noninvasive genetics over traditional methods in studying rare and elusive animals. Analyses from this sample suggested that the genetic diversity of wild Amur tigers is much lower than that of Bengal tigers, consistent with previous findings. Furthermore, the genetic diversity of this Hunchun population in China was lower than that of the adjoining subpopulation in southwest Primorye Russia, likely due to sampling bias. Considering the small population size and relatively low genetic diversity, it is urgent to protect this endangered local subpopulation in China. PMID:26663614

  4. Population Pharmacokinetics of Benznidazole in Adult Patients with Chagas Disease

    PubMed Central

    Aldasoro, E.; Guerrero, L.; Posada, E.; Serret, N.; Mejía, T.; Urbina, J. A.; Gascón, J.

    2015-01-01

    The aim of the present study was to build a population pharmacokinetic (popPK) model to characterize benznidazole (BNZ) pharmacokinetics in adults with chronic Chagas disease. This study was a prospective, open-label, single-center clinical trial approved by the local ethics committee. Patients received BNZ at 2.5 mg/kg of body weight/12 h (Abarax, Elea Laboratory, Argentina) for 60 days. Plasma BNZ samples were taken several times during the study and analyzed by high-performance liquid chromatography with UV-visible detection (HPLC-UV). The popPK analysis was done with NONMEMv.7.3. Demographic and biological data were tested as covariates. Intraindividual, interoccasion, and residual variabilities were modeled. Internal and external validations were completed to assess the robustness of the model. Later on, simulations were performed to generate BNZ concentration-time course profiles for different dosage regimens. A total of 358 plasma BNZ concentrations from 39 patients were included in the analysis. A one-compartment PK model characterized by clearance (CL/F) and the apparent volume of distribution (V/F), with first-order absorption (Ka) and elimination, adequately described the data (CL/F, 1.73 liters/h; V/F, 89.6 liters; and Ka, 1.15 h−1). No covariates were found to be significant for CL/F and V/F. Internal and external validations of the final model showed adequate results. Data from simulations revealed that a dose of 2.5 mg/kg/12 h might lead to overexposure in most patients. A lower dose (2.5 mg/kg/24 h) was able to achieve trough BNZ plasma concentrations within the accepted therapeutic range of 3 to 6 mg/liter. In summary, we developed a population PK model for BNZ in adults with chronic Chagas disease. Dosing simulations showed that a BNZ dose of 2.5 mg/kg/24 h will adequately keep BNZ trough plasma concentrations within the recommended target range for the majority of patients. (This study has been registered at EudraCT under number 2011

  5. Replicated origin of female-biased adult sex ratio in introduced populations of the trinidadian guppy (Poecilia reticulata).

    PubMed

    Arendt, Jeffrey D; Reznick, David N; López-Sepulcre, Andres

    2014-08-01

    There are many theoretical and empirical studies explaining variation in offspring sex ratio but relatively few that explain variation in adult sex ratio. Adult sex ratios are important because biased sex ratios can be a driver of sexual selection and will reduce effective population size, affecting population persistence and shapes how populations respond to natural selection. Previous work on guppies (Poecilia reticulata) gives mixed results, usually showing a female-biased adult sex ratio. However, a detailed analysis showed that this bias varied dramatically throughout a year and with no consistent sex bias. We used a mark-recapture approach to examine the origin and consistency of female-biased sex ratio in four replicated introductions. We show that female-biased sex ratio arises predictably and is a consequence of higher male mortality and longer female life spans with little effect of offspring sex ratio. Inconsistencies with previous studies are likely due to sampling methods and sampling design, which should be less of an issue with mark-recapture techniques. Together with other long-term mark-recapture studies, our study suggests that bias in offspring sex ratio rarely contributes to adult sex ratio in vertebrates. Rather, sex differences in adult survival rates and longevity determine vertebrate adult sex ratio.

  6. Can adult and juvenile European rabbits be differentiated by their pellet sizes?

    NASA Astrophysics Data System (ADS)

    Delibes-Mateos, Miguel; Rouco, Carlos; Villafuerte, Rafael

    2009-03-01

    Recently, a new method for differentiating juvenile and adult rabbits based on faecal pellet size was published. According to this method, pellets >6 mm diameter are inferred to be deposited by adults, while those <6 mm are inferred to be from juveniles or kittens. In this study, we designed a simple experiment to test the accuracy of this methodology. Twelve adult rabbits were housed in individual outdoor cages and their pellets were removed every day for 10 consecutive days. Pellets were separated using a sieve according to their size and counted. Results showed that adult rabbits produce pellets >6 mm diameter in the same proportion as those <6 mm. We also observed a strong influence of the individual rabbit on pellet size; some rabbits produce a high proportion of pellets >6 mm, whereas others deposit mostly pellets <6 mm in size. Our findings demonstrate that pellet size is unsuitable for aging wild rabbits. Field biologists should therefore be cautious when employing the pellet size method of age determination in other wild animals in the absence of validating studies.

  7. Does population size affect genetic diversity? A test with sympatric lizard species.

    PubMed

    Hague, M T J; Routman, E J

    2016-01-01

    Genetic diversity is a fundamental requirement for evolution and adaptation. Nonetheless, the forces that maintain patterns of genetic variation in wild populations are not completely understood. Neutral theory posits that genetic diversity will increase with a larger effective population size and the decreasing effects of drift. However, the lack of compelling evidence for a relationship between genetic diversity and population size in comparative studies has generated some skepticism over the degree that neutral sequence evolution drives overall patterns of diversity. The goal of this study was to measure genetic diversity among sympatric populations of related lizard species that differ in population size and other ecological factors. By sampling related species from a single geographic location, we aimed to reduce nuisance variance in genetic diversity owing to species differences, for example, in mutation rates or historical biogeography. We compared populations of zebra-tailed lizards and western banded geckos, which are abundant and short-lived, to chuckwallas and desert iguanas, which are less common and long-lived. We assessed population genetic diversity at three protein-coding loci for each species. Our results were consistent with the predictions of neutral theory, as the abundant species almost always had higher levels of haplotype diversity than the less common species. Higher population genetic diversity in the abundant species is likely due to a combination of demographic factors, including larger local population sizes (and presumably effective population sizes), faster generation times and high rates of gene flow with other populations.

  8. Place and type of meals consumed by adults in medium sized cities

    PubMed Central

    Carús, Juliana Pires; França, Giovanny V A; Barros, Aluísio J D

    2014-01-01

    OBJECTIVE To describe the meals consumed by adults living in a midsize city in the South of Brazil, according to the place and preparation. METHODS A population-based cross-sectional study was conducted in Pelotas, Southern Brazil, in 2012. The two-stage sampling design used the 2010 census tracts as primary sampling units. Data were collected on the place of meals (at home or out) and on the kind of preparations consumed at home (homemade, snacks, take away food) covering the two days prior to the interview, using a standardized questionnaire. RESULTS The study included 2,927 adults, of which 59.0% were female, 60.0% were below 50 years of age and 58.0% were in work. Data were collected on 11,581 meals consumed on the two days preceding the interview, 25.0% were consumed outside of the home at lunchtime, and 10.0% at dinnertime. Considering home meals, most participants reported eating food prepared at home at both lunch and dinner. The majority of out-of-home meals (64.0% for lunch and 61.0% for dinner) were consumed in the work place, mostly based on food prepared at home. Individuals eating out of home were mostly male, young and highly educated. The occupational categories that ate at restaurants more often were trade workers, businessmen, teachers and graduate professionals. CONCLUSIONS Despite the changes in eating patterns described in Brazil in recent years, residents of medium-sized towns still mostly eat at home, consuming homemade food. PMID:24789639

  9. Predicting adult stature from metatarsal length in a Portuguese population.

    PubMed

    Cordeiro, Cristina; Muñoz-Barús, José I; Wasterlain, Sofia; Cunha, Eugénia; Vieira, Duarte N

    2009-12-15

    Stature can be considered one of the "big four" parameters to be ascertained within the biological profile in cases of forensic anthropology. However, the most reliable available methods for stature estimation require the preservation of the long bones, but since this is very often not the case, the development of alternative methods, based on distinct bones, is mandatory. Therefore, in the present work the reliability of the first two metatarsal bones in reconstructing stature is tested. The data consist of length measurements taken from the first two metatarsals removed from documented cadavers of known stature. The sample for this study consists of 220 metatarsals, namely 110 first metatarsals and 110 second metatarsals collected during the autopsies carried out in the National Institute of Legal Medicine in Portugal. The aim was to propose regression equations for the Portuguese population and test the formulae proposed by other authors to determine adult stature using metatarsal bones. We found that when estimating stature from measurement of the metatarsals, the best correlation was that obtained from the relationship with the maximum length of the 2nd metatarsal. The corresponding regression equation is as follows: S=790.041+11.689M2.

  10. Perceived stress and mortality in a Taiwanese older adult population.

    PubMed

    Vasunilashorn, Sarinnapha; Glei, Dana A; Weinstein, Maxine; Goldman, Noreen

    2013-11-01

    Perceived stress is associated with poor health outcomes including negative affect, increased susceptibility to the common cold and cardiovascular disease; the consequences of perceived stress for mortality, however, have received less attention. This study characterizes the relationship between perceived stress and 11-year mortality in a population of Taiwanese adults aged 53+ years. Using the Survey of Health and Living Status of the Near Elderly and Elderly of Taiwan, we calculated a composite measure of perceived stress based on six items pertaining to the health, financial situation, and occupation of the respondents and their families. Proportional hazard models were used to determine whether perceived stress predicted mortality. After adjusting for sociodemographic factors only, we found that a one standard deviation increase in perceived stress was associated with a 19% increase in all-cause mortality risk during the 11-year follow-up period (hazard ratio, HR = 1.19, 95% confidence interval, CI 1.13-1.26). The relationship was greatly attenuated when perceptions of stress regarding health were excluded, and was not significant after adjusting for medical conditions, mobility limitations and depressive symptoms. We conclude that the association between perceived stress and mortality is explained by an individual's current health; however, our data do not allow us to distinguish between two possible interpretations of this conclusion: (a) the relationship between perceived stress and mortality is spurious, or (b) poor health acts as the mediator.

  11. Mortality during epizootics in bighorn sheep: effects of initial population size and cause.

    PubMed

    Cassaigne G, Ivonne; Medellín, Rodrigo A; Guasco O, José A

    2010-07-01

    One of the most severe threats to bighorn sheep (Ovis canadensis) populations is disease. With the objective of projecting possible epizootic consequences to bighorn sheep population dynamics, we examined 23 epizootic mortality episodes from presumably known causes that occurred in the United States and Canada from 1942 to 2005. These outbreaks were correlated with population size using regression models. Epizootic origins were documented by considering contact with a "new" pathogen for the bighorn sheep population or pneumonic processes, presumably triggered by stress. We suggest mortality rates are negatively related to population size in a logarithmic function, and offer a model to estimate the percentage of disease-related mortalities for a given population size of bighorn sheep. From a disease dynamics perspective, we suggest a minimum population of 188 bighorn sheep would be required to insure long-term persistence in the presence of epizootic disease.

  12. Size-at-birth standards for an urban Canadian population.

    PubMed Central

    Blidner, I. N.; McClemont, S.; Anderson, G. D.; Sinclair, J. C.

    1984-01-01

    By random sampling of all births occurring in Hamilton, Ont. over an 18-month period the percentile distributions of the newborn infants' weight, length, and head and chest circumferences were determined. The resulting standards may be used in the clinical evaluation of size for gestational age. The smoothed 50th percentile values for newborns of 40 weeks gestational age were as follows for boys and girls respectively: birth weight 3530 and 3355 g, crown-heel length 52.0 and 51.3 cm, head circumference 35.2 and 34.4 cm, and chest circumference 33.4 and 32.8 cm. The mother's height averaged 160.8 +/- 6.1 cm and her weight before the pregnancy 59.2 +/- 10.5 kg. The prevalence of cigarette smoking during pregnancy was 34.8%. PMID:6692192

  13. Needle Size and Injection Rate Impact Microbubble Contrast Agent Population

    PubMed Central

    Talu, Esra; Powell, Robert L.; Longo, Marjorie L.; Dayton, Paul A.

    2008-01-01

    The most common type of ultrasound contrast agents are encapsulated microbubbles, typically 1–5 microns in diameter. These microbubbles are injected into the bloodstream to provide image enhancement during an ultrasound exam. Due to their compressibility, these microbubbles are inherently sensitive to changes in pressure. For imaging, this is beneficial in that these microbubbles oscillate in an acoustic field and allow imaging systems to detect their response uniquely from tissue. However, this sensitivity also means that microbubbles can be readily destroyed by significant hydrostatic pressure. Injection of these microbubbles through a small-gauge catheter, such as sometimes performed in small animal imaging studies, can result in microbubble destruction. In this manuscript, the effects of microbubble injection through catheters of varying diameter are examined. Our results indicate that the concentration and size distribution of microbubbles can be substantially altered in cases of rapid injection through small needles. PMID:18295967

  14. Determining asymptotically large population sizes in insect swarms

    PubMed Central

    Puckett, James G.; Ouellette, Nicholas T.

    2014-01-01

    Social animals commonly form aggregates that exhibit emergent collective behaviour, with group dynamics that are distinct from the behaviour of individuals. Simple models can qualitatively reproduce such behaviour, but only with large numbers of individuals. But how rapidly do the collective properties of animal aggregations in nature emerge with group size? Here, we study swarms of Chironomus riparius midges and measure how their statistical properties change as a function of the number of participating individuals. Once the swarms contain order 10 individuals, we find that all statistics saturate and the swarms enter an asymptotic regime. The influence of environmental cues on the swarm morphology decays on a similar scale. Our results provide a strong constraint on how rapidly swarm models must produce collective states. But our findings support the feasibility of using swarms as a design template for multi-agent systems, because self-organized states are possible even with few agents. PMID:25121646

  15. Toothache and associated factors in Brazilian adults: a cross-sectional population-based study

    PubMed Central

    Kuhnen, Mirian; Peres, Marco A; Masiero, Anelise V; Peres, Karen G

    2009-01-01

    Background Toothache is a dental public health problem and one of the predictors of dental attendance and it is strongly associated with the life quality of individuals. In spite of this, there are few population-based epidemiological studies on this theme. Objective: To estimate the prevalence of toothache and associated factors in adults of Lages, Southern Brazil. Methods A cross-sectional population-based study was carried out in a sample of 2,022 adults aged 20 to 59 years living in the urban area of a medium sized city in Southern Brazil. A questionnaire including socioeconomic, demographic, smoking, alcohol, and use of dental service variables was applied at adults household. Toothache occurred six months previous of the interview was considered the outcome. Poisson regression analyses were performed following a theoretical hierarchical framework. All analysis was adjusted by the sample design effect. Results The response rate was 98.6%. The prevalence of toothache was 18.0% (95% CI 16.0; 20.1). The following variables were associated with toothache after adjustment: female (PR = 1.3 95% CI 1.3; 2.0), black skin colour vs. whites (PR = 1.5 95% CI 1.1, 1.9), low per capita income (PR = 1.7 95% CI 1.2, 2.3), smokers (PR = 1.5 95% CI 1.2, 1.9) and those who reported alcohol problems (PR = 1.4 95% CI 1.1; 1.9). To be 40 years of age (PR = 0.5 95% CI 0.4, 0.7) and use dental service in the last year (RR = 0.5 95% CI 0.4, 0.6) were protective factors for toothache. Conclusion The prevalence of toothache in adults of Lages can be considered a major problem of dental public health. PMID:19243630

  16. Impact of the 2010 Deepwater Horizon oil spill on population size and genetic structure of horse flies in Louisiana marshes.

    PubMed

    Husseneder, Claudia; Donaldson, Jennifer R; Foil, Lane D

    2016-01-01

    The greenhead horse fly, Tabanus nigrovittatus Macquart, is frequently found in coastal marshes of the Eastern United States. The greenhead horse fly larvae are top predators in the marsh and thus vulnerable to changes in the environment, and the adults potentially are attracted to polarized surfaces like oil. Therefore, horse fly populations could serve as bioindicators of marsh health and toxic effects of oil intrusion. In this study, we describe the impact of the April 2010 Deep Water Horizon oil spill in the Gulf of Mexico on tabanid population abundance and genetics as well as mating structure. Horse fly populations were sampled biweekly from oiled and unaffected locations immediately after the oil spill in June 2010 until October 2011. Horse fly abundance estimates showed severe crashes of tabanid populations in oiled areas. Microsatellite genotyping of six pristine and seven oiled populations at ten polymorphic loci detected genetic bottlenecks in six of the oiled populations in association with fewer breeding parents, reduced effective population size, lower number of family clusters and fewer migrants among populations. This is the first study assessing the impact of oil contamination at the level of a top arthropod predator of the invertebrate community in salt marshes. PMID:26755069

  17. Impact of the 2010 Deepwater Horizon oil spill on population size and genetic structure of horse flies in Louisiana marshes

    PubMed Central

    Husseneder, Claudia; Donaldson, Jennifer R.; Foil, Lane D.

    2016-01-01

    The greenhead horse fly, Tabanus nigrovittatus Macquart, is frequently found in coastal marshes of the Eastern United States. The greenhead horse fly larvae are top predators in the marsh and thus vulnerable to changes in the environment, and the adults potentially are attracted to polarized surfaces like oil. Therefore, horse fly populations could serve as bioindicators of marsh health and toxic effects of oil intrusion. In this study, we describe the impact of the April 2010 Deep Water Horizon oil spill in the Gulf of Mexico on tabanid population abundance and genetics as well as mating structure. Horse fly populations were sampled biweekly from oiled and unaffected locations immediately after the oil spill in June 2010 until October 2011. Horse fly abundance estimates showed severe crashes of tabanid populations in oiled areas. Microsatellite genotyping of six pristine and seven oiled populations at ten polymorphic loci detected genetic bottlenecks in six of the oiled populations in association with fewer breeding parents, reduced effective population size, lower number of family clusters and fewer migrants among populations. This is the first study assessing the impact of oil contamination at the level of a top arthropod predator of the invertebrate community in salt marshes. PMID:26755069

  18. Impact of the 2010 Deepwater Horizon oil spill on population size and genetic structure of horse flies in Louisiana marshes.

    PubMed

    Husseneder, Claudia; Donaldson, Jennifer R; Foil, Lane D

    2016-01-12

    The greenhead horse fly, Tabanus nigrovittatus Macquart, is frequently found in coastal marshes of the Eastern United States. The greenhead horse fly larvae are top predators in the marsh and thus vulnerable to changes in the environment, and the adults potentially are attracted to polarized surfaces like oil. Therefore, horse fly populations could serve as bioindicators of marsh health and toxic effects of oil intrusion. In this study, we describe the impact of the April 2010 Deep Water Horizon oil spill in the Gulf of Mexico on tabanid population abundance and genetics as well as mating structure. Horse fly populations were sampled biweekly from oiled and unaffected locations immediately after the oil spill in June 2010 until October 2011. Horse fly abundance estimates showed severe crashes of tabanid populations in oiled areas. Microsatellite genotyping of six pristine and seven oiled populations at ten polymorphic loci detected genetic bottlenecks in six of the oiled populations in association with fewer breeding parents, reduced effective population size, lower number of family clusters and fewer migrants among populations. This is the first study assessing the impact of oil contamination at the level of a top arthropod predator of the invertebrate community in salt marshes.

  19. Tree allometry, leaf size and adult tree size in old-growth forests of western Oregon.

    PubMed

    King, D A

    1991-10-01

    Relationships between tree height and crown dimensions and trunk diameter were determined for shade-tolerant species of old-growth forests of western Oregon. The study included both understory and overstory species, deciduous and evergreen angiosperms and evergreen conifers. A comparison of adult understory species with sapling overstory species of similar height showed greater crown width and trunk diameter in the former, whether the comparison is made among conifers or deciduous trees. Conifer saplings had wider crowns than deciduous saplings, but the crown widths of the two groups converged with increase in tree height. Conifer saplings had thicker trunks than deciduous saplings of similar crown width, possibly because of selection for resistance to stem bending under snow loads. The results suggest that understory species have morphologies that increase light interception and persistence in the understory, whereas overstory species allocate their biomass for efficient height growth, thereby attaining the high-light environment of the canopy. The greater crown widths and the additional strength requirements imposed by snow loads on conifer saplings result in less height growth per biomass increment in conifer saplings than in deciduous saplings. However, the convergence in crown width of the two groups at heights greater than 20 m, and the proportionately smaller effect of snow loads on large trees, may result in older conifers equalling or surpassing deciduous trees in biomass allocation to height growth.

  20. Crisis Model for Older Adults: Special Considerations for an Aging Population

    ERIC Educational Resources Information Center

    Jungers, Christin M.; Slagel, Leslie

    2009-01-01

    As the U.S. population ages, counselors must begin structuring their interactions to meet the unique needs of older adults, especially in the area of crisis intervention. The purposes of this article are to draw attention to the rapidly growing, often disregarded older population and to introduce the Crisis Model for Older Adults (CM-OA), an…

  1. [Study on preferred food of adult Mylabris phalerata in different geographical populations].

    PubMed

    Mo, Rang-yu; Sun, Nian-xi; Peng, Rui

    2014-11-01

    With the deterioration of environment, and the excessive collection of wild resources, the wild populations of Myla- bris phalerata Pallas are less and less, almost extincted in many traditional distribution areas. It is necessary to breed M. phalerata artificially for sustainable utilization. Food preference of adult M. phalerata is the key to its provenance screening and domestication in the artificial breeding. In this paper, the food preference of 3 geographical populations of M. phalerata was studied. The results showed that the food preferences of adult M. phalerata in different geographical populations were different. The adult M. phalerata in Wuming preferred cucumber flowers, gourd flowers and melon flowers. The adult M. phalerata in Tianlin preferred cowpea flowers. And the adult M. phalerata in Guangzhou preferred cowpea flowers and gourd flowers. Gourd flowers were the most attractive food for the adult M. phalerata of 3 geographical populations of M. phalerata. PMID:25850255

  2. Accuracy of Four Tooth Size Prediction Methods on Malay Population

    PubMed Central

    Mahmoud, Belal Khaled; Abu Asab, Saifeddin Hamed I.; Taib, Haslina

    2012-01-01

    Objective. To examine the accuracy of Moyers 50%, Tanaka and Johnston, Ling and Wong and Jaroontham and Godfrey methods in predicting the mesio-distal crown width of the permanent canines and premolars (C + P1 + P2) in Malay population. Materials and Methods. The study models of 240 Malay children (120 males and 120 females) aged 14 to 18 years, all free of any signs of dental pathology or anomalies, were measured using a digital caliper accurate to 0.01 mm. The predicted widths (C + P1 + P2) in both arches derived from the tested prediction equations were compared with the actual measured widths. Results. Moyers and Tanaka and Johnston methods showed significant difference between the actual and predicted widths of (C + P1 + P2) for both sexes. Ling and Wong method also showed statistically significant difference for males, however, there was no significant difference for females. Jaroontham and Godfrey method showed statistical significant difference for females, but the male values did not show any significant difference. Conclusion. For male Malay, the method proposed by Jaroontham and Godfrey for male Thai proved to be highly accurate. For female Malay, the method proposed by Ling and Wong for southern Chinese females proved to be highly accurate. PMID:23209918

  3. Estimation of the ancestral effective population sizes of African great apes under different selection regimes.

    PubMed

    Schrago, Carlos G

    2014-08-01

    Reliable estimates of ancestral effective population sizes are necessary to unveil the population-level phenomena that shaped the phylogeny and molecular evolution of the African great apes. Although several methods have previously been applied to infer ancestral effective population sizes, an analysis of the influence of the selective regime on the estimates of ancestral demography has not been thoroughly conducted. In this study, three independent data sets under different selective regimes were used were composed to tackle this issue. The results showed that selection had a significant impact on the estimates of ancestral effective population sizes of the African great apes. The inference of the ancestral demography of African great apes was affected by the selection regime. The effects, however, were not homogeneous along the ancestral populations of great apes. The effective population size of the ancestor of humans and chimpanzees was more impacted by the selection regime when compared to the same parameter in the ancestor of humans, chimpanzees and gorillas. Because the selection regime influenced the estimates of ancestral effective population size, it is reasonable to assume that a portion of the discrepancy found in previous studies that inferred the ancestral effective population size may be attributable to the differential action of selection on the genes sampled.

  4. Genome size differentiates co-occurring populations of the planktonic diatom Ditylum brightwellii (Bacillariophyta)

    PubMed Central

    2010-01-01

    Background Diatoms are one of the most species-rich groups of eukaryotic microbes known. Diatoms are also the only group of eukaryotic micro-algae with a diplontic life history, suggesting that the ancestral diatom switched to a life history dominated by a duplicated genome. A key mechanism of speciation among diatoms could be a propensity for additional stable genome duplications. Across eukaryotic taxa, genome size is directly correlated to cell size and inversely correlated to physiological rates. Differences in relative genome size, cell size, and acclimated growth rates were analyzed in isolates of the diatom Ditylum brightwellii. Ditylum brightwellii consists of two main populations with identical 18s rDNA sequences; one population is distributed globally at temperate latitudes and the second appears to be localized to the Pacific Northwest coast of the USA. These two populations co-occur within the Puget Sound estuary of WA, USA, although their peak abundances differ depending on local conditions. Results All isolates from the more regionally-localized population (population 2) possessed 1.94 ± 0.74 times the amount of DNA, grew more slowly, and were generally larger than isolates from the more globally distributed population (population 1). The ITS1 sequences, cell sizes, and genome sizes of isolates from New Zealand were the same as population 1 isolates from Puget Sound, but their growth rates were within the range of the slower-growing population 2 isolates. Importantly, the observed genome size difference between isolates from the two populations was stable regardless of time in culture or the changes in cell size that accompany the diatom life history. Conclusions The observed two-fold difference in genome size between the D. brightwellii populations suggests that whole genome duplication occurred within cells of population 1 ultimately giving rise to population 2 cells. The apparent regional localization of population 2 is consistent with a recent

  5. Utility of microcosm studies for predicting phylloplane bacterium population sizes in the field.

    PubMed

    Kinkel, L L; Wilson, M; Lindow, S E

    1996-09-01

    Population sizes of two ice nucleation-active strains of Pseudomonas syringae were compared on leaves in controlled environments and in the field to determine the ability of microcosm studies to predict plant habitat preferences in the field. The P. syringae strains investigated were the parental strains of recombinant deletion mutant strains deficient in ice nucleation activity that had been field tested for their ability to control plant frost injury. The population size of the P. syringae strains was measured after inoculation at three field locations on up to 40 of the same plant species that were studied in the growth chamber. There was seldom a significant relationship between the mean population size of a given P. syringae strain incubated under either wet or dry conditions in microcosms and the mean population size which could be recovered from the same species when inoculated in the field. Specifically, on some plant species, the population size recovered from leaves in the field was substantially greater than from that species in a controlled environment, while for other plant species field populations were significantly smaller than those observed under controlled conditions. Population sizes of inoculated P. syringae strains, however, were frequently highly positively correlated with the indigenous bacterial population size on the same plant species in the field, suggesting that the ability of a particular plant species to support introduced bacterial strains is correlated with its ability to support large bacterial populations or that indigenous bacteria enhance the survival of introduced strains. Microcosm studies therefore seem most effective at assessing possible differences between parental and recombinant strains under a given environmental regime but are limited in their ability to predict the specific population sizes or plant habitat preferences of bacteria on leaves under field conditions. PMID:16535405

  6. The adaptive significance of population differentiation in offspring size of the least killifish, Heterandria formosa

    PubMed Central

    Leips, Jeff; Helen Rodd, F; Travis, Joseph

    2013-01-01

    We tested the hypothesis that density-dependent competition influences the evolution of offspring size. We studied two populations of the least killifish (Heterandria formosa) that differ dramatically in population density; these populations are genetically differentiated for offspring size, and females from both populations produce larger offspring when they experience higher social densities. To look at the influences of population of origin and relative body size on competitive ability, we held females from the high-density population at two different densities to create large and small offspring with the same genetic background. We measured the competitive ability of those offspring in mesocosms that contained either pure or mixed population treatments at either high or low density. High density increased competition, which was most evident in greatly reduced individual growth rates. Larger offspring from the high-density population significantly delayed the onset of maturity of fish from the low-density population. From our results, we infer that competitive conditions in nature have contributed to the evolution of genetically based interpopulation differences in offspring size as well as plasticity in offspring size in response to conspecific density. PMID:23610636

  7. The roles of spatial pattern and size variation in shaping height inequality of plant population.

    PubMed

    Chen, Shu-Yan; Chen, Zi-long; Guo, Peng; Ding, Chen-Chen; Wang, Yu-xin; Wang, Xiang-tai; Zhang, Jia-Lin; Jia, Peng; Wang, Gang; Xiao, Sa

    2014-02-01

    Game-theoretic models predict that there is an ESS height for the plant population to which all individual plants should converge. To attain this conclusion, the neighborhood factors were assumed to be equal for all the individual plants, and the spatial pattern and size variation of population were left without consideration, which is clearly not right for the scenario of plant competition. We constructed a spatially-explicit, individual-based model to explore the impacts of spatial structure and size variation on individual plant's height and population's height hierarchies under the light competition. The monomorphic equilibrium of height that all the individual plants will converge to only exists for a population growing in a strictly uniform spatial pattern with no size variation. When the spatial pattern of the population is non-uniform or there's size variation among individual plants, the critical heights that individual plants will finally reach are different from each other, and the height inequality at the end of population growth will increase when the population's spatial pattern's degree of deviation from uniform and population's size variation increase. Our results argue strongly for the importance of spatial pattern and neighborhood effects in generating the diversity of population's height growth pattern.

  8. Estimate of intake of sulfites in the Belgian adult population.

    PubMed

    Vandevijvere, S; Temme, E; Andjelkovic, M; De Wil, M; Vinkx, C; Goeyens, L; Van Loco, J

    2010-08-01

    An exposure assessment was performed to estimate the usual daily intake of sulfites in the Belgian adult population. Food consumption data were retrieved from the national food consumption survey. In a first step, individual food consumption data were multiplied with the maximum permitted use levels for sulfites, expressed as sulphur dioxide, per food group (Tier 2). In a second step, on the basis of a literature review of the occurrence of sulfites in different foods, the results of the Tier 2 exposure assessment and available occurrence data from the control programme of the competent authority, a refined list of foods was drafted for the quantification of sulphite. Quantification of sulphite was performed by a high-performance ion chromatography method with eluent conductivity detector in beers and potato products. Individual food consumption data were then multiplied with the actual average concentrations of sulfite per food group, or the maximum permitted levels in case actual levels were not available (partial Tier 3). Usual intakes were calculated using the Nusser method. The mean intake of sulfites was 0.34 mg kg(-1) bw day(-1) (Tier 2), corresponding to 49% of the acceptable daily intake (ADI) and 0.19 mg kg(-1) bw day(-1), corresponding to 27% of the ADI (partial Tier 3). The food group contributing most to the intake of sulfites was wines. The results showed that the intake of sulfites is likely to be below the ADI in Belgium. However, there are indications that high consumers of wine have an intake around the ADI.

  9. Gaussian process-based Bayesian nonparametric inference of population size trajectories from gene genealogies.

    PubMed

    Palacios, Julia A; Minin, Vladimir N

    2013-03-01

    Changes in population size influence genetic diversity of the population and, as a result, leave a signature of these changes in individual genomes in the population. We are interested in the inverse problem of reconstructing past population dynamics from genomic data. We start with a standard framework based on the coalescent, a stochastic process that generates genealogies connecting randomly sampled individuals from the population of interest. These genealogies serve as a glue between the population demographic history and genomic sequences. It turns out that only the times of genealogical lineage coalescences contain information about population size dynamics. Viewing these coalescent times as a point process, estimating population size trajectories is equivalent to estimating a conditional intensity of this point process. Therefore, our inverse problem is similar to estimating an inhomogeneous Poisson process intensity function. We demonstrate how recent advances in Gaussian process-based nonparametric inference for Poisson processes can be extended to Bayesian nonparametric estimation of population size dynamics under the coalescent. We compare our Gaussian process (GP) approach to one of the state-of-the-art Gaussian Markov random field (GMRF) methods for estimating population trajectories. Using simulated data, we demonstrate that our method has better accuracy and precision. Next, we analyze two genealogies reconstructed from real sequences of hepatitis C and human Influenza A viruses. In both cases, we recover more believed aspects of the viral demographic histories than the GMRF approach. We also find that our GP method produces more reasonable uncertainty estimates than the GMRF method.

  10. Population structure among octocoral adults and recruits identifies scale dependent patterns of population isolation in The Bahamas.

    PubMed

    Lasker, Howard R; Porto-Hannes, Isabel

    2015-01-01

    Patterns of dispersal and connectivity of the Caribbean gorgonian Antillogorgia elisabethae in The Bahamas were assessed in both adults and recently settled recruits from 13 sites using microsatellite loci. Adult populations along the Little Bahama Bank (LBB) exhibited a clear pattern of isolation by distance (IBD) which described 86% of the variance in pairwise genetic distances. Estimates of dispersal based on the IBD model suggested dispersal distances along the LBB on the order of 100 m. Increasing the spatial scale to include sites separated by open ocean generated an apparent IBD signal but the relationship had a greater slope and explained less of the variance. This relationship with distance reflected both stepping stone based IBD and regional differentiation probably created by ocean currents and barriers to dispersal that are correlated with geographic distance. Analysis of recruits from 4 sites on the LBB from up to 6 years did not detect differences between years nor differences with adult populations. The result suggests that neither selection on recruits nor inter-annual variation in dispersal affected adult population structure. Assignment tests of recruits indicated the most likely sources of the recruits were the local or adjacent populations. Most of the patterning in population structure in the northern Bahamas can be explained by geographic distance and oceanographic connectivity. Recognition of these complex patterns is important in developing management plans for A. elisabethae and in understanding the effects of disturbance to adult populations of A. elisabethae and similar species with limited dispersal. PMID:26157606

  11. Population structure among octocoral adults and recruits identifies scale dependent patterns of population isolation in The Bahamas

    PubMed Central

    Porto-Hannes, Isabel

    2015-01-01

    Patterns of dispersal and connectivity of the Caribbean gorgonian Antillogorgia elisabethae in The Bahamas were assessed in both adults and recently settled recruits from 13 sites using microsatellite loci. Adult populations along the Little Bahama Bank (LBB) exhibited a clear pattern of isolation by distance (IBD) which described 86% of the variance in pairwise genetic distances. Estimates of dispersal based on the IBD model suggested dispersal distances along the LBB on the order of 100 m. Increasing the spatial scale to include sites separated by open ocean generated an apparent IBD signal but the relationship had a greater slope and explained less of the variance. This relationship with distance reflected both stepping stone based IBD and regional differentiation probably created by ocean currents and barriers to dispersal that are correlated with geographic distance. Analysis of recruits from 4 sites on the LBB from up to 6 years did not detect differences between years nor differences with adult populations. The result suggests that neither selection on recruits nor inter-annual variation in dispersal affected adult population structure. Assignment tests of recruits indicated the most likely sources of the recruits were the local or adjacent populations. Most of the patterning in population structure in the northern Bahamas can be explained by geographic distance and oceanographic connectivity. Recognition of these complex patterns is important in developing management plans for A. elisabethae and in understanding the effects of disturbance to adult populations of A. elisabethae and similar species with limited dispersal. PMID:26157606

  12. 46 CFR 160.171-17 - Approval testing for adult size immersion suit.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Approval testing for adult size immersion suit. Caution: During each of the in-water tests prescribed in this section, a person ready to render assistance when needed should be near each subject in the water... being immersed in water at 5 °C (41 °F) for a period of one hour, each subject must be able to pick up...

  13. 46 CFR 160.171-17 - Approval testing for adult size immersion suit.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Approval testing for adult size immersion suit. Caution: During each of the in-water tests prescribed in this section, a person ready to render assistance when needed should be near each subject in the water... being immersed in water at 5 °C (41 °F) for a period of one hour, each subject must be able to pick up...

  14. Shedding New Light on an Old Problem: The Estimation of Shadow Sizes in Children and Adults

    ERIC Educational Resources Information Center

    Ebersbach, Mirjam; Resing, Wilma C. M.

    2007-01-01

    Two experiments using the "projection of shadows" paradigm investigated multidimensional reasoning, implicit and explicit knowledge, and the nonlinearity concept in 5-, 9-, and 13-year-olds and adults. Participants estimated the resulting shadow lengths of differently sized objects, placed at varying distances from a light source. Experiment 1…

  15. Influence of habitat quality, population size, patch size, and connectivity on patch-occupancy dynamics of the middle spotted woodpecker.

    PubMed

    Robles, Hugo; Ciudad, Carlos

    2012-04-01

    Despite extensive research on the effects of habitat fragmentation, the ecological mechanisms underlying colonization and extinction processes are poorly known, but knowledge of these mechanisms is essential to understanding the distribution and persistence of populations in fragmented habitats. We examined these mechanisms through multiseason occupancy models that elucidated patch-occupancy dynamics of Middle Spotted Woodpeckers (Dendrocopos medius) in northwestern Spain. The number of occupied patches was relatively stable from 2000 to 2010 (15-24% of 101 patches occupied every year) because extinction was balanced by recolonization. Larger and higher quality patches (i.e., higher density of oaks >37 cm dbh [diameter at breast height]) were more likely to be occupied. Habitat quality (i.e., density of large oaks) explained more variation in patch colonization and extinction than did patch size and connectivity, which were both weakly associated with probabilities of turnover. Patches of higher quality were more likely to be colonized than patches of lower quality. Populations in high-quality patches were less likely to become extinct. In addition, extinction in a patch was strongly associated with local population size but not with patch size, which means the latter may not be a good surrogate of population size in assessments of extinction probability. Our results suggest that habitat quality may be a primary driver of patch-occupancy dynamics and may increase the accuracy of models of population survival. We encourage comparisons of competing models that assess occupancy, colonization, and extinction probabilities in a single analytical framework (e.g., dynamic occupancy models) so as to shed light on the association of habitat quality and patch geometry with colonization and extinction processes in different settings and species. PMID:22268847

  16. Influence of habitat quality, population size, patch size, and connectivity on patch-occupancy dynamics of the middle spotted woodpecker.

    PubMed

    Robles, Hugo; Ciudad, Carlos

    2012-04-01

    Despite extensive research on the effects of habitat fragmentation, the ecological mechanisms underlying colonization and extinction processes are poorly known, but knowledge of these mechanisms is essential to understanding the distribution and persistence of populations in fragmented habitats. We examined these mechanisms through multiseason occupancy models that elucidated patch-occupancy dynamics of Middle Spotted Woodpeckers (Dendrocopos medius) in northwestern Spain. The number of occupied patches was relatively stable from 2000 to 2010 (15-24% of 101 patches occupied every year) because extinction was balanced by recolonization. Larger and higher quality patches (i.e., higher density of oaks >37 cm dbh [diameter at breast height]) were more likely to be occupied. Habitat quality (i.e., density of large oaks) explained more variation in patch colonization and extinction than did patch size and connectivity, which were both weakly associated with probabilities of turnover. Patches of higher quality were more likely to be colonized than patches of lower quality. Populations in high-quality patches were less likely to become extinct. In addition, extinction in a patch was strongly associated with local population size but not with patch size, which means the latter may not be a good surrogate of population size in assessments of extinction probability. Our results suggest that habitat quality may be a primary driver of patch-occupancy dynamics and may increase the accuracy of models of population survival. We encourage comparisons of competing models that assess occupancy, colonization, and extinction probabilities in a single analytical framework (e.g., dynamic occupancy models) so as to shed light on the association of habitat quality and patch geometry with colonization and extinction processes in different settings and species.

  17. Variations in basic demographics consequential to population size of governorate in Saudi Arabia.

    PubMed

    Khraif, Rshood; Salam, Asharaf Abdul; Potty, Rajaram Subramanian; Aldosari, Ali; Elsegaey, Ibrahim; AlMutairi, Abdullah

    2016-01-01

    Saudi Arabia, divided into 5 planning regions, 13 administrative regions and further to 118 governorates (administrative units), has diverse demographic characteristics from one region to another and from one governorate to another. Rural to urban migration and an exodus of immigrants characterize the Kingdom, where development planning depend largely upon local level requirements based on economic activities. An attempt was made to analyze the population characteristics, such as population size, sex ratio, native to foreigner ratio, and households and persons per households by keeping governorate as unit of analysis. Data of two census period (2004 and 2010) was used in order to explore the situation and track the intercensal changes. Large variations in population were observed between governorates and it varied from 3686 to 5,007,886 in 2010. Governorates are divided according to the number of native population demarcating urbanization, modernization and infrastructure. During the intercensal period, the number of small governorates reduced and medium and large sized governorates increased mainly due to population growth. The average population in governorates was increased in total and in the larger governorates during the period. However, we noticed a reduction in the average population size in the small and medium sized governorates. The size of native population in a governorate influences the sex ratio, the native-foreigner ratio and the persons per household as well as the variations within the group of governorates. Analyses of lower level data shall aid not only to understand the situation but also to support local development policies. PMID:27652007

  18. Variations in basic demographics consequential to population size of governorate in Saudi Arabia.

    PubMed

    Khraif, Rshood; Salam, Asharaf Abdul; Potty, Rajaram Subramanian; Aldosari, Ali; Elsegaey, Ibrahim; AlMutairi, Abdullah

    2016-01-01

    Saudi Arabia, divided into 5 planning regions, 13 administrative regions and further to 118 governorates (administrative units), has diverse demographic characteristics from one region to another and from one governorate to another. Rural to urban migration and an exodus of immigrants characterize the Kingdom, where development planning depend largely upon local level requirements based on economic activities. An attempt was made to analyze the population characteristics, such as population size, sex ratio, native to foreigner ratio, and households and persons per households by keeping governorate as unit of analysis. Data of two census period (2004 and 2010) was used in order to explore the situation and track the intercensal changes. Large variations in population were observed between governorates and it varied from 3686 to 5,007,886 in 2010. Governorates are divided according to the number of native population demarcating urbanization, modernization and infrastructure. During the intercensal period, the number of small governorates reduced and medium and large sized governorates increased mainly due to population growth. The average population in governorates was increased in total and in the larger governorates during the period. However, we noticed a reduction in the average population size in the small and medium sized governorates. The size of native population in a governorate influences the sex ratio, the native-foreigner ratio and the persons per household as well as the variations within the group of governorates. Analyses of lower level data shall aid not only to understand the situation but also to support local development policies.

  19. Two-Locus Likelihoods Under Variable Population Size and Fine-Scale Recombination Rate Estimation.

    PubMed

    Kamm, John A; Spence, Jeffrey P; Chan, Jeffrey; Song, Yun S

    2016-07-01

    Two-locus sampling probabilities have played a central role in devising an efficient composite-likelihood method for estimating fine-scale recombination rates. Due to mathematical and computational challenges, these sampling probabilities are typically computed under the unrealistic assumption of a constant population size, and simulation studies have shown that resulting recombination rate estimates can be severely biased in certain cases of historical population size changes. To alleviate this problem, we develop here new methods to compute the sampling probability for variable population size functions that are piecewise constant. Our main theoretical result, implemented in a new software package called LDpop, is a novel formula for the sampling probability that can be evaluated by numerically exponentiating a large but sparse matrix. This formula can handle moderate sample sizes ([Formula: see text]) and demographic size histories with a large number of epochs ([Formula: see text]). In addition, LDpop implements an approximate formula for the sampling probability that is reasonably accurate and scales to hundreds in sample size ([Formula: see text]). Finally, LDpop includes an importance sampler for the posterior distribution of two-locus genealogies, based on a new result for the optimal proposal distribution in the variable-size setting. Using our methods, we study how a sharp population bottleneck followed by rapid growth affects the correlation between partially linked sites. Then, through an extensive simulation study, we show that accounting for population size changes under such a demographic model leads to substantial improvements in fine-scale recombination rate estimation. PMID:27182948

  20. Two-Locus Likelihoods Under Variable Population Size and Fine-Scale Recombination Rate Estimation.

    PubMed

    Kamm, John A; Spence, Jeffrey P; Chan, Jeffrey; Song, Yun S

    2016-07-01

    Two-locus sampling probabilities have played a central role in devising an efficient composite-likelihood method for estimating fine-scale recombination rates. Due to mathematical and computational challenges, these sampling probabilities are typically computed under the unrealistic assumption of a constant population size, and simulation studies have shown that resulting recombination rate estimates can be severely biased in certain cases of historical population size changes. To alleviate this problem, we develop here new methods to compute the sampling probability for variable population size functions that are piecewise constant. Our main theoretical result, implemented in a new software package called LDpop, is a novel formula for the sampling probability that can be evaluated by numerically exponentiating a large but sparse matrix. This formula can handle moderate sample sizes ([Formula: see text]) and demographic size histories with a large number of epochs ([Formula: see text]). In addition, LDpop implements an approximate formula for the sampling probability that is reasonably accurate and scales to hundreds in sample size ([Formula: see text]). Finally, LDpop includes an importance sampler for the posterior distribution of two-locus genealogies, based on a new result for the optimal proposal distribution in the variable-size setting. Using our methods, we study how a sharp population bottleneck followed by rapid growth affects the correlation between partially linked sites. Then, through an extensive simulation study, we show that accounting for population size changes under such a demographic model leads to substantial improvements in fine-scale recombination rate estimation.

  1. Demographic Demise: The Declining Young Adult Population in New England

    ERIC Educational Resources Information Center

    Gittell, Ross

    2007-01-01

    Young adult workers provide businesses with the dynamic labor force and fresh ideas they need to innovate and grow. With their contributions to cultural, intellectual and social life, young adults also make New England a vibrant and interesting place to live. Young families support local schools and demand a strong educational system. Yet New…

  2. Population size influences amphibian detection probability: implications for biodiversity monitoring programs.

    PubMed

    Tanadini, Lorenzo G; Schmidt, Benedikt R

    2011-01-01

    Monitoring is an integral part of species conservation. Monitoring programs must take imperfect detection of species into account in order to be reliable. Theory suggests that detection probability may be determined by population size but this relationship has not yet been assessed empirically. Population size is particularly important because it may induce heterogeneity in detection probability and thereby cause bias in estimates of biodiversity. We used a site occupancy model to analyse data from a volunteer-based amphibian monitoring program to assess how well different variables explain variation in detection probability. An index to population size best explained detection probabilities for four out of six species (to avoid circular reasoning, we used the count of individuals at a previous site visit as an index to current population size). The relationship between the population index and detection probability was positive. Commonly used weather variables best explained detection probabilities for two out of six species. Estimates of site occupancy probabilities differed depending on whether the population index was or was not used to model detection probability. The relationship between the population index and detectability has implications for the design of monitoring and species conservation. Most importantly, because many small populations are likely to be overlooked, monitoring programs should be designed in such a way that small populations are not overlooked. The results also imply that methods cannot be standardized in such a way that detection probabilities are constant. As we have shown here, one can easily account for variation in population size in the analysis of data from long-term monitoring programs by using counts of individuals from surveys at the same site in previous years. Accounting for variation in population size is important because it can affect the results of long-term monitoring programs and ultimately the conservation of

  3. Population Size Influences Amphibian Detection Probability: Implications for Biodiversity Monitoring Programs

    PubMed Central

    Tanadini, Lorenzo G.; Schmidt, Benedikt R.

    2011-01-01

    Monitoring is an integral part of species conservation. Monitoring programs must take imperfect detection of species into account in order to be reliable. Theory suggests that detection probability may be determined by population size but this relationship has not yet been assessed empirically. Population size is particularly important because it may induce heterogeneity in detection probability and thereby cause bias in estimates of biodiversity. We used a site occupancy model to analyse data from a volunteer-based amphibian monitoring program to assess how well different variables explain variation in detection probability. An index to population size best explained detection probabilities for four out of six species (to avoid circular reasoning, we used the count of individuals at a previous site visit as an index to current population size). The relationship between the population index and detection probability was positive. Commonly used weather variables best explained detection probabilities for two out of six species. Estimates of site occupancy probabilities differed depending on whether the population index was or was not used to model detection probability. The relationship between the population index and detectability has implications for the design of monitoring and species conservation. Most importantly, because many small populations are likely to be overlooked, monitoring programs should be designed in such a way that small populations are not overlooked. The results also imply that methods cannot be standardized in such a way that detection probabilities are constant. As we have shown here, one can easily account for variation in population size in the analysis of data from long-term monitoring programs by using counts of individuals from surveys at the same site in previous years. Accounting for variation in population size is important because it can affect the results of long-term monitoring programs and ultimately the conservation of

  4. Population size influences amphibian detection probability: implications for biodiversity monitoring programs.

    PubMed

    Tanadini, Lorenzo G; Schmidt, Benedikt R

    2011-01-01

    Monitoring is an integral part of species conservation. Monitoring programs must take imperfect detection of species into account in order to be reliable. Theory suggests that detection probability may be determined by population size but this relationship has not yet been assessed empirically. Population size is particularly important because it may induce heterogeneity in detection probability and thereby cause bias in estimates of biodiversity. We used a site occupancy model to analyse data from a volunteer-based amphibian monitoring program to assess how well different variables explain variation in detection probability. An index to population size best explained detection probabilities for four out of six species (to avoid circular reasoning, we used the count of individuals at a previous site visit as an index to current population size). The relationship between the population index and detection probability was positive. Commonly used weather variables best explained detection probabilities for two out of six species. Estimates of site occupancy probabilities differed depending on whether the population index was or was not used to model detection probability. The relationship between the population index and detectability has implications for the design of monitoring and species conservation. Most importantly, because many small populations are likely to be overlooked, monitoring programs should be designed in such a way that small populations are not overlooked. The results also imply that methods cannot be standardized in such a way that detection probabilities are constant. As we have shown here, one can easily account for variation in population size in the analysis of data from long-term monitoring programs by using counts of individuals from surveys at the same site in previous years. Accounting for variation in population size is important because it can affect the results of long-term monitoring programs and ultimately the conservation of

  5. Confidence intervals for population allele frequencies: the general case of sampling from a finite diploid population of any size.

    PubMed

    Fung, Tak; Keenan, Kevin

    2014-01-01

    The estimation of population allele frequencies using sample data forms a central component of studies in population genetics. These estimates can be used to test hypotheses on the evolutionary processes governing changes in genetic variation among populations. However, existing studies frequently do not account for sampling uncertainty in these estimates, thus compromising their utility. Incorporation of this uncertainty has been hindered by the lack of a method for constructing confidence intervals containing the population allele frequencies, for the general case of sampling from a finite diploid population of any size. In this study, we address this important knowledge gap by presenting a rigorous mathematical method to construct such confidence intervals. For a range of scenarios, the method is used to demonstrate that for a particular allele, in order to obtain accurate estimates within 0.05 of the population allele frequency with high probability (> or = 95%), a sample size of > 30 is often required. This analysis is augmented by an application of the method to empirical sample allele frequency data for two populations of the checkerspot butterfly (Melitaea cinxia L.), occupying meadows in Finland. For each population, the method is used to derive > or = 98.3% confidence intervals for the population frequencies of three alleles. These intervals are then used to construct two joint > or = 95% confidence regions, one for the set of three frequencies for each population. These regions are then used to derive a > or = 95%% confidence interval for Jost's D, a measure of genetic differentiation between the two populations. Overall, the results demonstrate the practical utility of the method with respect to informing sampling design and accounting for sampling uncertainty in studies of population genetics, important for scientific hypothesis-testing and also for risk-based natural resource management. PMID:24465792

  6. Factors and Mechanisms for Pharmacokinetic Differences between Pediatric Population and Adults

    PubMed Central

    Fernandez, Eva; Perez, Raul; Hernandez, Alfredo; Tejada, Pilar; Arteta, Marta; Ramos, Jose T.

    2011-01-01

    Many physiologic differences between children and adults may result in age-related changes in pharmacokinetics and pharmacodynamics. Factors such as gastric pH and emptying time, intestinal transit time, immaturity of secretion and activity of bile and pancreatic fluid among other factors determine the oral bioavailability of pediatric and adult populations. Anatomical, physiological and biochemical characteristics in children also affect the bioavailability of other routes of administration. Key factors explaining differences in drug distribution between the pediatric population and adults are membrane permeability, plasma protein binding and total body water. As far as drug metabolism is concerned, important differences have been found in the pediatric population compared with adults both for phase I and phase II metabolic enzymes. Immaturity of glomerular filtration, renal tubular secretion and tubular reabsorption at birth and their maturation determine the different excretion of drugs in the pediatric population compared to adults. PMID:24310425

  7. Increased Selection Response in Larger Populations. I. Selection for Wing-Tip Height in Drosophila Melanogaster at Three Population Sizes

    PubMed Central

    Weber, K. E.

    1990-01-01

    The effect of population size on selection response was investigated with replicated selection lines of 40, 200 and 1000 selected parents, using Drosophila melanogaster homozygous for the mutant raised. Selection for increased wing-tip height was carried out for 55 generations, with an average selection intensity of 0.6 standard deviation. The rank order of responses in the seven individual lines was significantly in order of population size, and the variance of response among lines showed a significant effect of population size. The final mean responses (selected - controls, +/- standard errors) in the three treatments, in order of increasing population size, were 8.6 +/- 1.8 mils (three small lines), 15.1 +/- 1.3 mils (two medium lines), and 19.8 +/- 1.5 mils (two large lines). The differences between treatments seem to have emerged too rapidly to be the result of mutations, and are probably due mainly to the utilization of existing variation with greater efficiency by selection in larger populations. PMID:2116358

  8. Within- and among-population impact of genetic erosion on adult fitness-related traits in the European tree frog Hyla arborea.

    PubMed

    Luquet, E; Léna, J-P; David, P; Prunier, J; Joly, P; Lengagne, T; Perrin, N; Plénet, S

    2013-04-01

    Assessing in wild populations how fitness is impacted by inbreeding and genetic drift is a major goal for conservation biology. An approach to measure the detrimental effects of inbreeding on fitness is to estimate correlations between molecular variation and phenotypic performances within and among populations. Our study investigated the effect of individual multilocus heterozygosity on body size, body condition and reproductive investment of males (that is, chorus attendance) and females (that is, clutch mass and egg size) in both small fragmented and large non-fragmented populations of European tree frog (Hyla arborea). Because adult size and/or condition and reproductive investment are usually related, genetic erosion may have detrimental effects directly on reproductive investment, and also on individual body size and condition that in turn may affect reproductive investment. We confirmed that the reproductive investment was highly size-dependent for both sexes. Larger females invested more in offspring production, and larger males attended the chorus in the pond more often. Our results did not provide evidence for a decline in body size, condition and reproductive effort with decreased multilocus heterozygosity both within and among populations. We showed that the lack of heterozygosity-fitness correlations within populations probably resulted from low inbreeding levels (inferior to ca. 20% full-sib mating rate), even in the small fragmented populations. The detrimental effects of fixation load were either low in adults or hidden by environmental variation among populations. These findings will be useful to design specific management actions to improve population persistence.

  9. Cranioplasty for Large-Sized Calvarial Defects in the Pediatric Population: A Review

    PubMed Central

    Lam, Sandi; Kuether, Justin; Fong, Abigail; Reid, Russell

    2014-01-01

    Large-sized calvarial defects in pediatric patients pose a reconstructive challenge because of children's unique physiology, developing anatomy, and dynamic growth. We review the current literature and outcomes with autologous and alloplastic cranioplasty in the pediatric population. PMID:26000090

  10. Effects of Overlapping Generations on Linkage Disequilibrium Estimates of Effective Population Size

    PubMed Central

    Waples, Robin S.; Antao, Tiago; Luikart, Gordon

    2014-01-01

    Use of single-sample genetic methods to estimate effective population size has skyrocketed in recent years. Although the underlying models assume discrete generations, they are widely applied to age-structured species. We simulated genetic data for 21 iteroparous animal and plant species to evaluate two untested hypotheses regarding performance of the single-sample method based on linkage disequilibrium (LD): (1) estimates based on single-cohort samples reflect the effective number of breeders in one reproductive cycle (Nb), and (2) mixed-age samples reflect the effective size per generation (Ne). We calculated true Ne and Nb, using the model species’ vital rates, and verified these with individual-based simulations. We show that single-cohort samples should be equally influenced by Nb and Ne and confirm this with simulated results: N^b was a linear (r2 = 0.98) function of the harmonic mean of Ne and Nb. We provide a quantitative bias correction for raw N^b based on the ratio Nb/Ne, which can be estimated from two or three simple life history traits. Bias-adjusted estimates were within 5% of true Nb for all 21 study species and proved robust when challenged with new data. Mixed-age adult samples produced downwardly biased estimates in all species, which we attribute to a two-locus Wahlund effect (mixture LD) caused by combining parents from different cohorts in a single sample. Results from this study will facilitate interpretation of rapidly accumulating genetic estimates in terms of both Ne (which influences long-term evolutionary processes) and Nb (which is more important for understanding eco-evolutionary dynamics and mating systems). PMID:24717176

  11. Organ dose conversion coefficients for tube current modulated CT protocols for an adult population

    NASA Astrophysics Data System (ADS)

    Fu, Wanyi; Tian, Xiaoyu; Sahbaee, Pooyan; Zhang, Yakun; Segars, William Paul; Samei, Ehsan

    2016-03-01

    In computed tomography (CT), patient-specific organ dose can be estimated using pre-calculated organ dose conversion coefficients (organ dose normalized by CTDIvol, h factor) database, taking into account patient size and scan coverage. The conversion coefficients have been previously estimated for routine body protocol classes, grouped by scan coverage, across an adult population for fixed tube current modulated CT. The coefficients, however, do not include the widely utilized tube current (mA) modulation scheme, which significantly impacts organ dose. This study aims to extend the h factors and the corresponding dose length product (DLP) to create effective dose conversion coefficients (k factor) database incorporating various tube current modulation strengths. Fifty-eight extended cardiac-torso (XCAT) phantoms were included in this study representing population anatomy variation in clinical practice. Four mA profiles, representing weak to strong mA dependency on body attenuation, were generated for each phantom and protocol class. A validated Monte Carlo program was used to simulate the organ dose. The organ dose and effective dose was further normalized by CTDIvol and DLP to derive the h factors and k factors, respectively. The h factors and k factors were summarized in an exponential regression model as a function of body size. Such a population-based mathematical model can provide a comprehensive organ dose estimation given body size and CTDIvol. The model was integrated into an iPhone app XCATdose version 2, enhancing the 1st version based upon fixed tube current modulation. With the organ dose calculator, physicists, physicians, and patients can conveniently estimate organ dose.

  12. Time and size at metamorphosis related to adult fitness in Ambystoma talpoideum

    SciTech Connect

    Semlitsch, R.D.; Scott, D.E.; Pechmann, J.H.K.

    1988-02-01

    The relationships among timing of metamorphosis, size at metamorphosis, and traits related to adult fitness were studied for 8 yr in the salamander Ambystoma talpoideum at a temporary pond. Among years, the modal time of metamorphosis and mean body size at metamorphosis were positively correlated with the date the pond dried. In years that the pond dried late, one group of larvae metamorphosed well before the pond dried, whereas the other group metamorphosed just before pond drying. Mean body size of late-metamorphosing individuals was not greater than that of individuals metamorphosing early. Early-metamorphosing males and females were larger at first and second reproduction than were late-metamorphosing individuals. Independent of timing of metamorphosis, larger juveniles at metamorphosis were also larger adults at first reproduction. Age at first reproduction for males was not associated with timing of or size at metamorphosis but large early-metamorphosing females reproduced at a younger age than did small early-metamorphosing females. Neither time of metamorphosis nor size at metamorphosis was associated with survival to first reproduction. These results demonstrate a direct relationship between phenotypic variation generated in the larval stage and adult traits closely associated with an individual's fitness.

  13. Temporal Variation in Population Size of European Bird Species: Effects of Latitude and Marginality of Distribution

    PubMed Central

    Cuervo, José J.; Møller, Anders P.

    2013-01-01

    In the Northern Hemisphere, global warming has been shown to affect animal populations in different ways, with southern populations in general suffering more from increased temperatures than northern populations of the same species. However, southern populations are also often marginal populations relative to the entire breeding range, and marginality may also have negative effects on populations. To disentangle the effects of latitude (possibly due to global warming) and marginality on temporal variation in population size, we investigated European breeding bird species across a latitudinal gradient. Population size estimates were regressed on years, and from these regressions we obtained the slope (a proxy for population trend) and the standard error of the estimate (SEE) (a proxy for population fluctuations). The possible relationships between marginality or latitude on one hand and slopes or SEE on the other were tested among populations within species. Potentially confounding factors such as census method, sampling effort, density-dependence, habitat fragmentation and number of sampling years were controlled statistically. Population latitude was positively related to regression slopes independent of marginality, with more positive slopes (i.e., trends) in northern than in southern populations. The degree of marginality was positively related to SEE independent of latitude, with marginal populations showing larger SEE (i.e., fluctuations) than central ones. Regression slopes were also significantly related to our estimate of density-dependence and SEE was significantly affected by the census method. These results are consistent with a scenario in which southern and northern populations of European bird species are negatively affected by marginality, with southern populations benefitting less from global warming than northern populations, thus potentially making southern populations more vulnerable to extinction. PMID:24147048

  14. Temporal variation in population size of European bird species: effects of latitude and marginality of distribution.

    PubMed

    Cuervo, José J; Møller, Anders P

    2013-01-01

    In the Northern Hemisphere, global warming has been shown to affect animal populations in different ways, with southern populations in general suffering more from increased temperatures than northern populations of the same species. However, southern populations are also often marginal populations relative to the entire breeding range, and marginality may also have negative effects on populations. To disentangle the effects of latitude (possibly due to global warming) and marginality on temporal variation in population size, we investigated European breeding bird species across a latitudinal gradient. Population size estimates were regressed on years, and from these regressions we obtained the slope (a proxy for population trend) and the standard error of the estimate (SEE) (a proxy for population fluctuations). The possible relationships between marginality or latitude on one hand and slopes or SEE on the other were tested among populations within species. Potentially confounding factors such as census method, sampling effort, density-dependence, habitat fragmentation and number of sampling years were controlled statistically. Population latitude was positively related to regression slopes independent of marginality, with more positive slopes (i.e., trends) in northern than in southern populations. The degree of marginality was positively related to SEE independent of latitude, with marginal populations showing larger SEE (i.e., fluctuations) than central ones. Regression slopes were also significantly related to our estimate of density-dependence and SEE was significantly affected by the census method. These results are consistent with a scenario in which southern and northern populations of European bird species are negatively affected by marginality, with southern populations benefitting less from global warming than northern populations, thus potentially making southern populations more vulnerable to extinction.

  15. First molar size and wear within and among modern hunter-gatherers and agricultural populations.

    PubMed

    Górka, Katarzyna; Romero, Alejandro; Pérez-Pérez, Alejandro

    2015-08-01

    Apart from reflecting modern human dental variation, differences in dental size among populations provide a means for studying continuous evolutionary processes and their mechanisms. Dental wear, on the other hand, has been widely used to infer dietary adaptations and variability among or within diverse ancient human populations. Few such studies have focused on modern foragers and farmers, however, and diverse methods have been used. This research aimed to apply a single, standardized, and systematic quantitative procedure to measure dental size and dentin exposure in order to analyze differences among several hunter-gatherer and agricultural populations from various environments and geographic origins. In particular, we focused on sexual dimorphism and intergroup differences in the upper and lower first molars. Results indicated no sexual dimorphism in molar size and wear within the studied populations. Despite the great ethnographic variation in subsistence strategies among these populations, our findings suggest that differences in sexual division of labor do not affect dietary wear patterns. PMID:26032341

  16. Modeling of LEO Orbital Debris Populations in Centimeter and Millimeter Size Regimes

    NASA Technical Reports Server (NTRS)

    Xu, Y.-L.; Hill, . M.; Horstman, M.; Krisko, P. H.; Liou, J.-C.; Matney, M.; Stansbery, E. G.

    2010-01-01

    The building of the NASA Orbital Debris Engineering Model, whether ORDEM2000 or its recently updated version ORDEM2010, uses as its foundation a number of model debris populations, each truncated at a minimum object-size ranging from 10 micron to 1 m. This paper discusses the development of the ORDEM2010 model debris populations in LEO (low Earth orbit), focusing on centimeter (smaller than 10 cm) and millimeter size regimes. Primary data sets used in the statistical derivation of the cm- and mm-size model populations are from the Haystack radar operated in a staring mode. Unlike cataloged objects of sizes greater than approximately 10 cm, ground-based radars monitor smaller-size debris only in a statistical manner instead of tracking every piece. The mono-static Haystack radar can detect debris as small as approximately 5 mm at moderate LEO altitudes. Estimation of millimeter debris populations (for objects smaller than approximately 6 mm) rests largely on Goldstone radar measurements. The bi-static Goldstone radar can detect 2- to 3-mm objects. The modeling of the cm- and mm-debris populations follows the general approach to developing other ORDEM2010-required model populations for various components and types of debris. It relies on appropriate reference populations to provide necessary prior information on the orbital structures and other important characteristics of the debris objects. NASA's LEO-to-GEO Environment Debris (LEGEND) model is capable of furnishing such reference populations in the desired size range. A Bayesian statistical inference process, commonly adopted in ORDEM2010 model-population derivations, changes a priori distribution into a posteriori distribution and thus refines the reference populations in terms of data. This paper describes key elements and major steps in the statistical derivations of the cm- and mm-size debris populations and presents results. Due to lack of data for near 1-mm sizes, the model populations of 1- to 3.16-mm

  17. Joint effects of population size and isolation on genetic erosion in fragmented populations: finding fragmentation thresholds for management

    PubMed Central

    Méndez, María; Vögeli, Matthias; Tella, José L; Godoy, José A

    2014-01-01

    Size and isolation of local populations are main parameters of interest when assessing the genetic consequences of habitat fragmentation. However, their relative influence on the genetic erosion of local populations remains unclear. In this study, we first analysed how size and isolation of habitat patches influence the genetic variation of local populations of the Dupont's lark (Chersophilus duponti), an endangered songbird. An information-theoretic approach to model selection allowed us to address the importance of interactions between habitat variables, an aspect seldom considered in fragmentation studies, but which explained up to 65% of the variance in genetic parameters. Genetic diversity and inbreeding were influenced by the size of local populations depending on their degree of isolation, and genetic differentiation was positively related to isolation. We then identified a minimum local population of 19 male territories and a maximum distance of 30 km to the nearest population as thresholds from which genetic erosion becomes apparent. Our results alert on possibly misleading conclusions and suboptimal management recommendations when only additive effects are taken into account and encourage the use of most explanatory but easy-to-measure variables for the evaluation of genetic risks in conservation programmes. PMID:24822084

  18. Adult survival and population growth rate in Colorado big brown bats (Eptesicus fuscus)

    USGS Publications Warehouse

    O'Shea, T.J.; Ellison, L.E.; Stanley, T.R.

    2011-01-01

    We studied adult survival and population growth at multiple maternity colonies of big brown bats (Eptesicus fuscus) in Fort Collins, Colorado. We investigated hypotheses about survival using information-theoretic methods and mark-recapture analyses based on passive detection of adult females tagged with passive integrated transponders. We constructed a 3-stage life-history matrix model to estimate population growth rate (??) and assessed the relative importance of adult survival and other life-history parameters to population growth through elasticity and sensitivity analysis. Annual adult survival at 5 maternity colonies monitored from 2001 to 2005 was estimated at 0.79 (95% confidence interval [95% CI] = 0.77-0.82). Adult survival varied by year and roost, with low survival during an extreme drought year, a finding with negative implications for bat populations because of the likelihood of increasing drought in western North America due to global climate change. Adult survival during winter was higher than in summer, and mean life expectancies calculated from survival estimates were lower than maximum longevity records. We modeled adult survival with recruitment parameter estimates from the same population. The study population was growing (?? = 1.096; 95% CI = 1.057-1.135). Adult survival was the most important demographic parameter for population growth. Growth clearly had the highest elasticity to adult survival, followed by juvenile survival and adult fecundity (approximately equivalent in rank). Elasticity was lowest for fecundity of yearlings. The relative importances of the various life-history parameters for population growth rate are similar to those of large mammals. ?? 2011 American Society of Mammalogists.

  19. The influence of host fruit and temperature on the body size of adult Ceratitis capitata (Diptera: Tephritidae) under laboratory and field conditions.

    PubMed

    Navarro-Campos, C; Martínez-Ferrer, M T; Campos, J M; Fibla, J M; Alcaide, J; Bargues, L; Marzal, C; Garcia-Marí, F

    2011-08-01

    The adult body size of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), varies in natural conditions. Body size is an important fitness indicator in the Mediterranean fruit fly; larger individuals are more competitive at mating and have a greater dispersion capacity and fertility. Both temperature during larval development and host fruit quality have been cited as possible causes for this variation. We studied the influence of host fruit and temperature during larval development on adult body size (wing area) in the laboratory, and determined body size variation in field populations of the Mediterannean fruit fly in eastern Spain. Field flies measured had two origins: 1) flies periodically collected throughout the year in field traps from 32 citrus groves, during the period 2003-2007; and 2) flies evolved from different fruit species collected between June and December in 2003 and 2004. In the lab, wing area of male and female adults varied significantly with temperature during larval development, being larger at the lowest temperature. Adult size also was significantly different depending on the host fruit in which larvae developed. The size of the flies captured at the field, either from traps or from fruits, varied seasonally showing a gradual pattern of change along the year. The largest individuals were obtained during winter and early spring and the smallest during late summer. In field conditions, the size of the adult Mediterannean fruit fly seems apparently more related with air temperature than with host fruit. The implications of this adult size pattern on the biology of C. capitata and on the application of the sterile insect technique are discussed.

  20. Recovery trajectories after burn injury in young adults: does burn size matter?

    PubMed

    Ryan, Colleen M; Lee, Austin; Kazis, Lewis E; Schneider, Jeffrey C; Shapiro, Gabriel D; Sheridan, Robert L; Meyer, Walter J; Palmieri, Tina; Pidcock, Frank S; Reilly, Debra; Tompkins, Ronald G

    2015-01-01

    The impact of burn size on mortality is well known, but the association of burn size with the trajectories of long-term functional outcomes remains poorly studied. This prospective multi-center study included burned adults ages 19 to 30 years who completed the Young Adult Burn Outcome Questionnaire at initial baseline contact, 2 weeks, and at 6 and 12 months after initial questionnaire administration. Non-burned adults of comparable ages also completed the questionnaire as a reference group. The association between functional recovery and TBSA burned was analyzed longitudinally using generalized linear models with the generalized estimation equation technique. Functional status was characterized in 15 domains: physical function, fine motor function, pain, itch, social function limited by physical function, perceived appearance, social function limited by appearance, sexual function, emotion, family function, family concern, satisfaction with symptom relief, satisfaction with role, work reintegration, and religion. Scores were standardized to a mean of 50 and a SD of 10 based on non-burned controls. There were 153 burned and 112 non-burned subjects with a total of 620 questionnaires. TBSA burned was 11 ± 14% (mean ± SD); 31% had face involvement and 57% had hand involvement. The lag time from burn injury to questionnaire administration was on average 7 ± 7.7 months, with a maximum of 36 months. Lower recovery levels were associated with increasing burn size for physical function, pain, itch, work reintegration, emotion, satisfaction with symptom relief, satisfaction with role, family function, and family concern (P value ranged from .04-<.0001). No significant differences in recovery levels were found with increasing burn size for fine motor function, social function limited by physical function, sexual function, and religion; these areas tracked toward the age-matched non-burned group regardless of burn size. Perceived appearance and social function limited by

  1. Effective population size is positively correlated with levels of adaptive divergence among annual sunflowers.

    PubMed

    Strasburg, Jared L; Kane, Nolan C; Raduski, Andrew R; Bonin, Aurélie; Michelmore, Richard; Rieseberg, Loren H

    2011-05-01

    The role of adaptation in the divergence of lineages has long been a central question in evolutionary biology, and as multilocus sequence data sets have become available for a wide range of taxa, empirical estimates of levels of adaptive molecular evolution are increasingly common. Estimates vary widely among taxa, with high levels of adaptive evolution in Drosophila, bacteria, and viruses but very little evidence of widespread adaptive evolution in hominids. Although estimates in plants are more limited, some recent work has suggested that rates of adaptive evolution in a range of plant taxa are surprisingly low and that there is little association between adaptive evolution and effective population size in contrast to patterns seen in other taxa. Here, we analyze data from 35 loci for six sunflower species that vary dramatically in effective population size. We find that rates of adaptive evolution are positively correlated with effective population size in these species, with a significant fraction of amino acid substitutions driven by positive selection in the species with the largest effective population sizes but little or no evidence of adaptive evolution in species with smaller effective population sizes. Although other factors likely contribute as well, in sunflowers effective population size appears to be an important determinant of rates of adaptive evolution.

  2. Statistical Estimation of Orbital Debris Populations with a Spectrum of Object Size

    NASA Astrophysics Data System (ADS)

    Xu, Yu-Lin; Horstman, Matthew; Krisko, Paula; Liou, J.-C.; Matney, Mark; Stansbery, Eugene; Stokely, Christopher; Whitlock, David

    Orbital debris is a real concern for the safe operations of satellites. In general, the hazard of debris impact is a function of the size and spatial distributions of the debris populations. To describe and characterize the debris environment as reliably as possible, the current NASA Orbital Debris Engineering Model (ORDEM2000) is being upgraded to a new version based on new and better-quality data. The data-driven ORDEM model covers a wide range of object sizes from 10 microns to greater than 1 meter. This paper reviews the statistical process for the estimation of the debris populations in the new ORDEM upgrade, and discusses the representation of large-size (≥1 m and ≥10 cm) populations by SSN catalog objects and the validation of the statistical approach. Also, it presents results for the populations with sizes of ≥3.3 cm, ≥1 cm, ≥100 µm, and ≥10 µm. The orbital debris populations used in the new version of ORDEM are inferred from data based upon appropriate reference (or benchmark) populations instead of the binning of the multi-dimensional orbital-element space. This paper describes all of the major steps used in the population-inference procedure for each size-range. Detailed discussions on data analysis, parameter definition, the correlation between parameters and data, and uncertainty assessment are included.

  3. Statistical Estimation of Orbital Debris Populations with a Spectrum of Object Size

    NASA Technical Reports Server (NTRS)

    Xu, Y. -l; Horstman, M.; Krisko, P. H.; Liou, J. -C; Matney, M.; Stansbery, E. G.; Stokely, C. L.; Whitlock, D.

    2008-01-01

    Orbital debris is a real concern for the safe operations of satellites. In general, the hazard of debris impact is a function of the size and spatial distributions of the debris populations. To describe and characterize the debris environment as reliably as possible, the current NASA Orbital Debris Engineering Model (ORDEM2000) is being upgraded to a new version based on new and better quality data. The data-driven ORDEM model covers a wide range of object sizes from 10 microns to greater than 1 meter. This paper reviews the statistical process for the estimation of the debris populations in the new ORDEM upgrade, and discusses the representation of large-size (greater than or equal to 1 m and greater than or equal to 10 cm) populations by SSN catalog objects and the validation of the statistical approach. Also, it presents results for the populations with sizes of greater than or equal to 3.3 cm, greater than or equal to 1 cm, greater than or equal to 100 micrometers, and greater than or equal to 10 micrometers. The orbital debris populations used in the new version of ORDEM are inferred from data based upon appropriate reference (or benchmark) populations instead of the binning of the multi-dimensional orbital-element space. This paper describes all of the major steps used in the population-inference procedure for each size-range. Detailed discussions on data analysis, parameter definition, the correlation between parameters and data, and uncertainty assessment are included.

  4. Relation of adult size to movements and distribution of smallmouth bass in a central Maine Lake

    USGS Publications Warehouse

    Cole, M.B.; Moring, J.R.

    1997-01-01

    Forty-four smallmouth bass Micropterus dolomieu of three size-classes were radiotracked in Green Lake, Maine, during summer 1993 (10 June-1 September) to determine whether adult size influenced distribution and movement. Large smallmouth bass (>406 mm) used deep water (>8 m) more often than did small (248-279 mm) or medium-sized (305-356 mm) smallmouth bass during the late summer (15 July-1 September). Large smallmouth bass also were found at middepths (4-8 m) significantly more often than were small individuals during late summer. Small fish used cover more frequently than large ones during early summer (10 June-13 July). Both small and medium-sized individuals were associated with cover more frequently than large smallmouth bass were during the late summer. Small smallmouth bass exhibited significantly smaller summer total ranges than did large individuals, and mean active displacement differed among all three size-classes.

  5. Faltering lemming cycles reduce productivity and population size of a migratory Arctic goose species.

    PubMed

    Nolet, Bart A; Bauer, Silke; Feige, Nicole; Kokorev, Yakov I; Popov, Igor Yu; Ebbinge, Barwolt S

    2013-07-01

    The huge changes in population sizes of Arctic-nesting geese offer a great opportunity to study population limitation in migratory animals. In geese, population limitation seems to have shifted from wintering to summering grounds. There, in the Arctic, climate is rapidly changing, and this may impact reproductive performance, and perhaps population size of geese, both directly (e.g. by changes in snow melt) or indirectly (e.g. by changes in trophic interactions). Dark-bellied brent geese (Branta bernicla bernicla L.) increased 20-fold since the 1950s. Its reproduction fluctuates strongly in concert with the 3-year lemming cycle. An earlier analysis, covering the growth period until 1988, did not find evidence for density dependence, but thereafter the population levelled off and even decreased. The question is whether this is caused by changes in lemming cycles, population density or other factors like carry-over effects. Breeding success was derived from proportions of juveniles. We used an information-theoretical approach to investigate which environmental factors best explained the variation in breeding success over nearly 50 years (1960-2008). We subsequently combined GLM predictions of breeding success with published survival estimates to project the population trajectory since 1991 (year of maximum population size). In this way, we separated the effects of lemming abundance and population density on population development. Breeding success was mainly dependent on lemming abundance, the onset of spring at the breeding grounds, and the population size of brent goose. No evidence was found for carry-over effects (i.e. effects of conditions at main spring staging site). Negative density dependence was operating at a population size above c. 200 000 individuals, but the levelling off of the population could be explained by faltering lemming cycles alone. Lemmings have long been known to affect population productivity of Arctic-nesting migratory birds and, more

  6. Faltering lemming cycles reduce productivity and population size of a migratory Arctic goose species

    PubMed Central

    Nolet, Bart A; Bauer, Silke; Feige, Nicole; Kokorev, Yakov I; Popov, Igor Yu; Ebbinge, Barwolt S

    2013-01-01

    1. The huge changes in population sizes of Arctic-nesting geese offer a great opportunity to study population limitation in migratory animals. In geese, population limitation seems to have shifted from wintering to summering grounds. There, in the Arctic, climate is rapidly changing, and this may impact reproductive performance, and perhaps population size of geese, both directly (e.g. by changes in snow melt) or indirectly (e.g. by changes in trophic interactions). 2. Dark-bellied brent geese (Branta bernicla bernicla L.) increased 20-fold since the 1950s. Its reproduction fluctuates strongly in concert with the 3-year lemming cycle. An earlier analysis, covering the growth period until 1988, did not find evidence for density dependence, but thereafter the population levelled off and even decreased. The question is whether this is caused by changes in lemming cycles, population density or other factors like carry-over effects. 3. Breeding success was derived from proportions of juveniles. We used an information-theoretical approach to investigate which environmental factors best explained the variation in breeding success over nearly 50 years (1960–2008). We subsequently combined GLM predictions of breeding success with published survival estimates to project the population trajectory since 1991 (year of maximum population size). In this way, we separated the effects of lemming abundance and population density on population development. 4. Breeding success was mainly dependent on lemming abundance, the onset of spring at the breeding grounds, and the population size of brent goose. No evidence was found for carry-over effects (i.e. effects of conditions at main spring staging site). Negative density dependence was operating at a population size above c. 200 000 individuals, but the levelling off of the population could be explained by faltering lemming cycles alone. 5. Lemmings have long been known to affect population productivity of Arctic-nesting migratory

  7. Faltering lemming cycles reduce productivity and population size of a migratory Arctic goose species.

    PubMed

    Nolet, Bart A; Bauer, Silke; Feige, Nicole; Kokorev, Yakov I; Popov, Igor Yu; Ebbinge, Barwolt S

    2013-07-01

    The huge changes in population sizes of Arctic-nesting geese offer a great opportunity to study population limitation in migratory animals. In geese, population limitation seems to have shifted from wintering to summering grounds. There, in the Arctic, climate is rapidly changing, and this may impact reproductive performance, and perhaps population size of geese, both directly (e.g. by changes in snow melt) or indirectly (e.g. by changes in trophic interactions). Dark-bellied brent geese (Branta bernicla bernicla L.) increased 20-fold since the 1950s. Its reproduction fluctuates strongly in concert with the 3-year lemming cycle. An earlier analysis, covering the growth period until 1988, did not find evidence for density dependence, but thereafter the population levelled off and even decreased. The question is whether this is caused by changes in lemming cycles, population density or other factors like carry-over effects. Breeding success was derived from proportions of juveniles. We used an information-theoretical approach to investigate which environmental factors best explained the variation in breeding success over nearly 50 years (1960-2008). We subsequently combined GLM predictions of breeding success with published survival estimates to project the population trajectory since 1991 (year of maximum population size). In this way, we separated the effects of lemming abundance and population density on population development. Breeding success was mainly dependent on lemming abundance, the onset of spring at the breeding grounds, and the population size of brent goose. No evidence was found for carry-over effects (i.e. effects of conditions at main spring staging site). Negative density dependence was operating at a population size above c. 200 000 individuals, but the levelling off of the population could be explained by faltering lemming cycles alone. Lemmings have long been known to affect population productivity of Arctic-nesting migratory birds and, more

  8. Population Size and Suicide in U.S. Cities: A Static and Dynamic Exploration

    ERIC Educational Resources Information Center

    McCall, Patricia L.; Tittle, Charles R.

    2007-01-01

    The relationship between city population size and suicide rates rarely has been examined directly, though scholars often assume such a relationship exists based on studies of the association between suicide rates and urbanization (percent of the population living in cities) in various social contexts. In an effort to determine the basic…

  9. Man in Balance with the Environment: Pollution and the Optimal Population Size

    ERIC Educational Resources Information Center

    Ultsch, Gordon R.

    1973-01-01

    Discusses the relationship between population size and pollution, and suggests that the optimal population level toward which we should strive would be that level at which man is in balance with the biosphere in terms of pollution production and degradation, coupled with a harmless steady-state background pollution level. (JR)

  10. Characteristics of the variance effective population size over time using an age structured model with variable size.

    PubMed

    Olsson, Fredrik; Hössjer, Ola; Laikre, Linda; Ryman, Nils

    2013-12-01

    The variance effective population size (NeV) is a key concept in population biology, because it quantifies the microevolutionary process of random genetic drift, and understanding the characteristics of NeV is thus of central importance. Current formulas for NeV for populations with overlapping generations weight age classes according to their reproductive values (i.e. reflecting the contribution of genes from separate age classes to the population growth) to obtain a correct measure of genetic drift when computing the variance of the allele frequency change over time. In this paper, we examine the effect of applying different weights to the age classes using a novel analytical approach for exploring NeV. We consider a haploid organism with overlapping generations and populations of increasing, declining, or constant expected size and stochastic variation with respect to the number of individuals in the separate age classes. We define NeV, as a function of how the age classes are weighted, and of the span between the two points in time, when measuring allele frequency change. With this model, time profiles for NeV can be calculated for populations with various life histories and with fluctuations in life history composition, using different weighting schemes. We examine analytically and by simulations when NeV, using a weighting scheme with respect to reproductive contribution of separate age classes, accurately reflect the variance of the allele frequency change due to genetic drift over time. We show that the discrepancy of NeV, calculated with reproductive values as weights, compared to when individuals are weighted equally, tends to a constant when the time span between the two measurements increases. This constant is zero only for a population with a constant expected population size. Our results confirm that the effect of ignoring overlapping generations, when empirically assessing NeV from allele frequency shifts, gets smaller as the time interval between

  11. 45 CFR Appendix C to Part 1356 - Calculating Sample Size for NYTD Follow-Up Populations

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 4 2010-10-01 2010-10-01 false Calculating Sample Size for NYTD Follow-Up Populations C Appendix C to Part 1356 Public Welfare Regulations Relating to Public Welfare (Continued) OFFICE... REQUIREMENTS APPLICABLE TO TITLE IV-E Pt. 1356, App. C Appendix C to Part 1356—Calculating Sample Size for...

  12. Central limit theorem for variable size simple random sampling from a finite population

    SciTech Connect

    Wright, T.

    1986-02-01

    This paper introduces a sampling plan for finite populations herein called ''variable size simple random sampling'' and compares properties of estimators based on it with results from the usual fixed size simple random sampling without replacement. Necessary and sufficient conditions (in the spirit of Hajek) for the limiting distribution of the sample total (or sample mean) to be normal are given. 19 refs.

  13. The lifecycle effects of nutrition and body size on adult adiposity, diabetes and cardiovascular disease.

    PubMed

    Yajnik, C S

    2002-08-01

    This study was undertaken to review the links between maternal nutrition, offspring's birth weight and the propensity to early insulin resistance and high diabetes rates in Indian adults. Studies included a comparison of maternal size and nutrition with birth weights in Pune, India, and Southampton, UK. In Pune, the growth, insulin resistance and blood pressure of four-year-old children were assessed. Adults >40 years of age, who were resident in rural areas, were compared with adults living in urban areas for size, glucose handling, lipid status and blood pressure. Newly diagnosed diabetic adults living in urban areas were also monitored. Height, weight, head, waist and hip circumferences, skin-fold measurements and blood pressure were routinely measured. Fasting glucose, insulin, total and high-density lipoprotein cholesterol and triglycerides were linked to the glucose and insulin responses during glucose tolerance tests. Cytokine levels were measured in plasma samples of urban and rural adults. Indian babies were lighter, thinner, shorter and had a relatively lower lean tissue mass than the Caucasian babies. However, the subcutaneous fat measurements of these babies were comparable to those of the white Caucasian babies. The Indian mothers were small, but relatively fat mothers produced larger babies. Maternal intake of green vegetables, fruit and milk, and their circulating folate and vitamin C levels, predicted larger fetal size. Rapid childhood growth promoted insulin resistance and higher blood pressure. Rural adults were thin, with a 4% prevalence of diabetes and a 14% prevalence of hypertension, but the risks increased within the normal body mass index (BMI) range. Type 2 diabetes was common in urban adults younger than 35 years of age. Although the average BMI was 23.9 kg m(-2), central obesity and thin limbs were noteworthy. Levels of interleukin-6 and tumour necrosis factor-a were markedly increased in urban dwellers. Hence, there is evidence of a

  14. The lifecycle effects of nutrition and body size on adult adiposity, diabetes and cardiovascular disease.

    PubMed

    Yajnik, C S

    2002-08-01

    This study was undertaken to review the links between maternal nutrition, offspring's birth weight and the propensity to early insulin resistance and high diabetes rates in Indian adults. Studies included a comparison of maternal size and nutrition with birth weights in Pune, India, and Southampton, UK. In Pune, the growth, insulin resistance and blood pressure of four-year-old children were assessed. Adults >40 years of age, who were resident in rural areas, were compared with adults living in urban areas for size, glucose handling, lipid status and blood pressure. Newly diagnosed diabetic adults living in urban areas were also monitored. Height, weight, head, waist and hip circumferences, skin-fold measurements and blood pressure were routinely measured. Fasting glucose, insulin, total and high-density lipoprotein cholesterol and triglycerides were linked to the glucose and insulin responses during glucose tolerance tests. Cytokine levels were measured in plasma samples of urban and rural adults. Indian babies were lighter, thinner, shorter and had a relatively lower lean tissue mass than the Caucasian babies. However, the subcutaneous fat measurements of these babies were comparable to those of the white Caucasian babies. The Indian mothers were small, but relatively fat mothers produced larger babies. Maternal intake of green vegetables, fruit and milk, and their circulating folate and vitamin C levels, predicted larger fetal size. Rapid childhood growth promoted insulin resistance and higher blood pressure. Rural adults were thin, with a 4% prevalence of diabetes and a 14% prevalence of hypertension, but the risks increased within the normal body mass index (BMI) range. Type 2 diabetes was common in urban adults younger than 35 years of age. Although the average BMI was 23.9 kg m(-2), central obesity and thin limbs were noteworthy. Levels of interleukin-6 and tumour necrosis factor-a were markedly increased in urban dwellers. Hence, there is evidence of a

  15. Estimating variable effective population sizes from multiple genomes: a sequentially markov conditional sampling distribution approach.

    PubMed

    Sheehan, Sara; Harris, Kelley; Song, Yun S

    2013-07-01

    Throughout history, the population size of modern humans has varied considerably due to changes in environment, culture, and technology. More accurate estimates of population size changes, and when they occurred, should provide a clearer picture of human colonization history and help remove confounding effects from natural selection inference. Demography influences the pattern of genetic variation in a population, and thus genomic data of multiple individuals sampled from one or more present-day populations contain valuable information about the past demographic history. Recently, Li and Durbin developed a coalescent-based hidden Markov model, called the pairwise sequentially Markovian coalescent (PSMC), for a pair of chromosomes (or one diploid individual) to estimate past population sizes. This is an efficient, useful approach, but its accuracy in the very recent past is hampered by the fact that, because of the small sample size, only few coalescence events occur in that period. Multiple genomes from the same population contain more information about the recent past, but are also more computationally challenging to study jointly in a coalescent framework. Here, we present a new coalescent-based method that can efficiently infer population size changes from multiple genomes, providing access to a new store of information about the recent past. Our work generalizes the recently developed sequentially Markov conditional sampling distribution framework, which provides an accurate approximation of the probability of observing a newly sampled haplotype given a set of previously sampled haplotypes. Simulation results demonstrate that we can accurately reconstruct the true population histories, with a significant improvement over the PSMC in the recent past. We apply our method, called diCal, to the genomes of multiple human individuals of European and African ancestry to obtain a detailed population size change history during recent times.

  16. Estimating Variable Effective Population Sizes from Multiple Genomes: A Sequentially Markov Conditional Sampling Distribution Approach

    PubMed Central

    Sheehan, Sara; Harris, Kelley; Song, Yun S.

    2013-01-01

    Throughout history, the population size of modern humans has varied considerably due to changes in environment, culture, and technology. More accurate estimates of population size changes, and when they occurred, should provide a clearer picture of human colonization history and help remove confounding effects from natural selection inference. Demography influences the pattern of genetic variation in a population, and thus genomic data of multiple individuals sampled from one or more present-day populations contain valuable information about the past demographic history. Recently, Li and Durbin developed a coalescent-based hidden Markov model, called the pairwise sequentially Markovian coalescent (PSMC), for a pair of chromosomes (or one diploid individual) to estimate past population sizes. This is an efficient, useful approach, but its accuracy in the very recent past is hampered by the fact that, because of the small sample size, only few coalescence events occur in that period. Multiple genomes from the same population contain more information about the recent past, but are also more computationally challenging to study jointly in a coalescent framework. Here, we present a new coalescent-based method that can efficiently infer population size changes from multiple genomes, providing access to a new store of information about the recent past. Our work generalizes the recently developed sequentially Markov conditional sampling distribution framework, which provides an accurate approximation of the probability of observing a newly sampled haplotype given a set of previously sampled haplotypes. Simulation results demonstrate that we can accurately reconstruct the true population histories, with a significant improvement over the PSMC in the recent past. We apply our method, called diCal, to the genomes of multiple human individuals of European and African ancestry to obtain a detailed population size change history during recent times. PMID:23608192

  17. Geographical variation of skull size and shape in various populations in the black giant squirrel.

    PubMed

    Endo, Hideki; Kimura, Junpei; Oshida, Tatsuo; Stafford, Brian J; Rerkamnuaychoke, Worawut; Nishida, Takao; Sasaki, Motoki; Hayashida, Akiko; Hayashi, Yoshihiro

    2004-10-01

    We osteometrically examined the skulls of the black giant squirrel (Ratufa bicolor) from three mainland populations (M. Malayan Peninsula, V. South Vietnam, and B. Burma, India and North Thailand) and from two island populations (T. Tioman, and S. Sumatra Islands). The skull in the Malayan peninsula population was significantly smaller than that of the two other mainland populations. It is consistent with Bergmann's rule as shown in the gray-bellied squirrel. The two island populations did not show obvious differences in comparison with the Malayan population in many measurements. In the proportion analysis eliminating the size factor, the differences among populations were not easily confirmed and we concluded that the osteological characters peculiar to each population could not be shown in this species. The first and second principal component scores of M, S, and T populations were intermingled, whereas the V and B populations of V and B were not separated in the chart. We pointed out that the morphological differences were demonstrated between northern and southern groups of the Isthmus of Kra in the mainland populations, and that the two island populations did not show the island-isolation effect in comparison with the M population. The adaptational variation related to feeding and locomotion could not be confirmed among populations of the black giant squirrel as shown in the proportion analysis. PMID:15528851

  18. When bigger is not better: intraspecific competition for pollination increases with population size in invasive milkweeds.

    PubMed

    Ward, Megan; Johnson, Steven D; Zalucki, Myron P

    2013-04-01

    One of the essential requirements for an introduced plant species to become invasive is an ability to reproduce outside the native range, particularly when initial populations are small. If a reproductive Allee effect is operating, plants in small populations will have reduced reproductive success relative to plants in larger populations. Alternatively, if plants in small populations experience less competition for pollination than those in large populations, they may actually have higher levels of reproductive success than plants in large populations. To resolve this uncertainty, we investigated how the per capita fecundity of plants was affected by population size in three invasive milkweed species. Field surveys of seed production in natural populations of different sizes but similar densities were conducted for three pollinator-dependent invasive species, namely Asclepias curassavica, Gomphocarpus fruticosus and G. physocarpus. Additionally, supplemental hand-pollinations were performed in small and large populations in order to determine whether reproductive output was limited by pollinator activity in these populations. Reproductive Allee effects were not detected in any of the study species. Instead, plants in small populations exhibited remarkably high levels of reproductive output compared to those in large populations. Increased fruit production following supplemental hand-pollinations suggested that the lower reproductive output of naturally pollinated plants in large populations is a consequence of pollen limitation rather than limitation due to abiotic resources. This is consistent with increased intraspecific competition for pollination amongst plants in large populations. It is likely that the invasion of these milkweed species in Australia has been enhanced because plants in small founding populations experience less intraspecific competition for pollinators than those in large populations, and thus have the ability to produce copious amounts of

  19. Diphyllobothrium nihonkaiense: wide egg size variation in 32 molecularly confirmed adult specimens from Korea.

    PubMed

    Choi, Seoyun; Cho, Jaeeun; Jung, Bong-Kwang; Kim, Deok-Gyu; Jeon, Sarah Jiyoun; Jeon, Hyeong-Kyu; Eom, Keeseon S; Chai, Jong-Yil

    2015-06-01

    The eggs of Diphyllobothrium nihonkaiense were reported to be smaller than those of the classical Diphyllobothrium latum in general. However, verification using a large number of adult tapeworms is required. We assessed the egg size variation in 32 adult specimens of D. nihonkaiense recovered from Korean patients in 1975-2014. The diagnosis of individual specimens was based on analysis of the mitochondrial cytochrome c oxidase 1 gene sequence. Uterine eggs (n = 10) were obtained from each specimen, and their length and width were measured by micrometry. The results indicated that the egg size of D. nihonkaiense (total number of eggs measured, 320) was widely variable according to individual specimens, 54-76 μm long (mean 64) and 35-58 μm wide (mean 45), with a length-width ratio of 1.32-1.70 (mean 1.46). The worm showing the smallest egg size had a length range of 54-62 μm, whereas the one showing the largest egg size had a length range of 68-76 μm. The two ranges did not overlap, and a similar pattern was observed for the egg width. Mapping of each egg size (n = 320) showed a wide variation in length and width. The widely variable egg size of D. nihonkaiense cannot be used for specific diagnosis of diphyllobothriid tapeworm infections in human patients.

  20. Contrasting dynamics of a mutator allele in asexual populations of differing size.

    PubMed

    Raynes, Yevgeniy; Gazzara, Matthew R; Sniegowski, Paul D

    2012-07-01

    Mutators have been shown to hitchhike in asexual populations when the anticipated beneficial mutation supply rate of the mutator subpopulation, NU(b) (for subpopulation of size N and beneficial mutation rate U(b)) exceeds that of the wild-type subpopulation. Here, we examine the effect of total population size on mutator dynamics in asexual experimental populations of Saccharomyces cerevisiae. Although mutators quickly hitchhike to fixation in smaller populations, mutator fixation requires more and more time as population size increases; this observed delay in mutator hitchhiking is consistent with the expected effect of clonal interference. Interestingly, despite their higher beneficial mutation supply rate, mutators are supplanted by the wild type in very large populations. We postulate that this striking reversal in mutator dynamics is caused by an interaction between clonal interference, the fitness cost of the mutator allele, and infrequent large-effect beneficial mutations in our experimental populations. Our work thus identifies a potential set of circumstances under which mutator hitchhiking can be inhibited in natural asexual populations, despite recent theoretical predictions that such populations should have a net tendency to evolve ever-higher genomic mutation rates.

  1. Nonidentifiability of population size from capture-recapture data with heterogeneous detection probabilities

    USGS Publications Warehouse

    Link, W.A.

    2003-01-01

    Heterogeneity in detection probabilities has long been recognized as problematic in mark-recapture studies, and numerous models developed to accommodate its effects. Individual heterogeneity is especially problematic, in that reasonable alternative models may predict essentially identical observations from populations of substantially different sizes. Thus even with very large samples, the analyst will not be able to distinguish among reasonable models of heterogeneity, even though these yield quite distinct inferences about population size. The problem is illustrated with models for closed and open populations.

  2. Population size-structure-dependent fitness and ecosystem consequences in Trinidadian guppies.

    PubMed

    Bassar, Ronald D; Heatherly, Thomas; Marshall, Michael C; Thomas, Steven A; Flecker, Alexander S; Reznick, David N

    2015-07-01

    Decades of theory and recent empirical results have shown that evolutionary, population, community and ecosystem properties are the result of feedbacks between ecological and evolutionary processes. The vast majority of theory and empirical research on these eco-evolutionary feedbacks has focused on interactions among population size and mean traits of populations. However, numbers and mean traits represent only a fraction of the possible feedback dimensions. Populations of many organisms consist of different size classes that differ in their impact on the environment and each other. Moreover, rarely do we know the map of ecological pathways through which changes in numbers or size structure cause evolutionary change. The goal of this study was to test the role of size structure in eco-evolutionary feedbacks of Trinidadian guppies and to begin to build an eco-evolutionary map along this unexplored dimension. We used a factorial experiment in mesocosms wherein we crossed high- and low-predation guppy phenotypes with population size structure. We tested the ability of changes in size structure to generate selection on the demographic rates of guppies using an integral projection model (IPM). To understand how fitness differences among high- and low-predation phenotypes may be generated, we measured the response of the biomass of lower trophic levels and nutrient cycling to the different phenotype and size structure treatments. We found a significant interaction between guppy phenotype and the size structure treatments for absolute fitness. Size structure had a very large effect on invertebrate biomass in the mesocosms, but there was little or no effect of the phenotype. The effect of size structure on algal biomass depended on guppy phenotype, with no difference in algal biomass in populations with more, smaller guppies, but a large decrease in algal biomass in mesocosms with phenotypes adapted to low-predation risk. These results indicate an important role for size

  3. Population size-structure-dependent fitness and ecosystem consequences in Trinidadian guppies.

    PubMed

    Bassar, Ronald D; Heatherly, Thomas; Marshall, Michael C; Thomas, Steven A; Flecker, Alexander S; Reznick, David N

    2015-07-01

    Decades of theory and recent empirical results have shown that evolutionary, population, community and ecosystem properties are the result of feedbacks between ecological and evolutionary processes. The vast majority of theory and empirical research on these eco-evolutionary feedbacks has focused on interactions among population size and mean traits of populations. However, numbers and mean traits represent only a fraction of the possible feedback dimensions. Populations of many organisms consist of different size classes that differ in their impact on the environment and each other. Moreover, rarely do we know the map of ecological pathways through which changes in numbers or size structure cause evolutionary change. The goal of this study was to test the role of size structure in eco-evolutionary feedbacks of Trinidadian guppies and to begin to build an eco-evolutionary map along this unexplored dimension. We used a factorial experiment in mesocosms wherein we crossed high- and low-predation guppy phenotypes with population size structure. We tested the ability of changes in size structure to generate selection on the demographic rates of guppies using an integral projection model (IPM). To understand how fitness differences among high- and low-predation phenotypes may be generated, we measured the response of the biomass of lower trophic levels and nutrient cycling to the different phenotype and size structure treatments. We found a significant interaction between guppy phenotype and the size structure treatments for absolute fitness. Size structure had a very large effect on invertebrate biomass in the mesocosms, but there was little or no effect of the phenotype. The effect of size structure on algal biomass depended on guppy phenotype, with no difference in algal biomass in populations with more, smaller guppies, but a large decrease in algal biomass in mesocosms with phenotypes adapted to low-predation risk. These results indicate an important role for size

  4. Population variation and individual maximum size in two leech populations: energy extraction from cannibalism or niche widening?

    PubMed

    Persson, Lennart; Elliott, J Malcolm

    2013-05-01

    The theory of cannibal dynamics predicts a link between population dynamics and individual life history. In particular, increased individual growth has, in both modeling and empirical studies, been shown to result from a destabilization of population dynamics. We used data from a long-term study of the dynamics of two leech (Erpobdella octoculata) populations to test the hypothesis that maximum size should be higher in a cycling population; one of the study populations exhibited a delayed feedback cycle while the other population showed no sign of cyclicity. A hump-shaped relationship between individual mass of 1-year-old leeches and offspring density the previous year was present in both populations. As predicted from the theory, the maximum mass of individuals was much larger in the fluctuating population. In contrast to predictions, the higher growth rate was not related to energy extraction from cannibalism. Instead, the higher individual mass is suggested to be due to increased availability of resources due to a niche widening with increased individual body mass. The larger individual mass in the fluctuating population was related to a stronger correlation between the densities of 1-year-old individuals and 2-year-old individuals the following year in this population. Although cannibalism was the major mechanism regulating population dynamics, its importance was negligible in terms of providing cannibalizing individuals with energy subsequently increasing their fecundity. Instead, the study identifies a need for theoretical and empirical studies on the largely unstudied interplay between ontogenetic niche shifts and cannibalistic population dynamics. PMID:23053229

  5. Using pedigree reconstruction to estimate population size: genotypes are more than individually unique marks

    PubMed Central

    Creel, Scott; Rosenblatt, Elias

    2013-01-01

    Estimates of population size are critical for conservation and management, but accurate estimates are difficult to obtain for many species. Noninvasive genetic methods are increasingly used to estimate population size, particularly in elusive species such as large carnivores, which are difficult to count by most other methods. In most such studies, genotypes are treated simply as unique individual identifiers. Here, we develop a new estimator of population size based on pedigree reconstruction. The estimator accounts for individuals that were directly sampled, individuals that were not sampled but whose genotype could be inferred by pedigree reconstruction, and individuals that were not detected by either of these methods. Monte Carlo simulations show that the population estimate is unbiased and precise if sampling is of sufficient intensity and duration. Simulations also identified sampling conditions that can cause the method to overestimate or underestimate true population size; we present and discuss methods to correct these potential biases. The method detected 2–21% more individuals than were directly sampled across a broad range of simulated sampling schemes. Genotypes are more than unique identifiers, and the information about relationships in a set of genotypes can improve estimates of population size. PMID:23762516

  6. Factors determining the average body size of geographically separated Arctodiaptomus salinus (Daday, 1885) populations

    PubMed Central

    Anufriieva, Elena V.; Shadrin, Nickolai V.

    2014-01-01

    Arctodiaptomus salinus inhabits water bodies across Eurasia and North Africa. Based on our own data and that from the literature, we analyzed the influences of several factors on the intra- and inter-population variability of this species. A strong negative linear correlation between temperature and average body size in the Crimean and African populations was found, in which the parameters might be influenced by salinity. Meanwhile, asignificant negative correlation between female body size and the altitude of habitats was found by comparing body size in populations from different regions. Individuals from environments with highly varying abiotic parameters, e.g. temporary reservoirs, had a larger body size than individuals from permanent water bodies. The changes in average body mass in populations were at 11.4 times, whereas, those in individual metabolic activities were at 6.2 times. Moreover, two size groups of A. salinus in the Crimean and the Siberian lakes were observed. The ratio of female length to male length fluctuatedbetween 1.02 and 1.30. The average size of A. salinus in populations and its variations were determined by both genetic and environmental factors. However, the paritiesof these factors were unequal in either spatial or temporal scales. PMID:24668656

  7. Population Size and Cultural Evolution in Nonindustrial Food-Producing Societies

    PubMed Central

    Collard, Mark; Ruttle, April; Buchanan, Briggs; O’Brien, Michael J.

    2013-01-01

    Modeling work suggests that population size affects cultural evolution such that larger populations can be expected to have richer and more complex cultural repertoires than smaller populations. Empirical tests of this hypothesis, however, have yielded conflicting results. Here, we report a study in which we investigated whether the subsistence toolkits of small-scale food-producers are influenced by population size in the manner the hypothesis predicts. We applied simple linear and standard multiple regression analysis to data from 40 nonindustrial farming and pastoralist groups to test the hypothesis. Results were consistent with predictions of the hypothesis: both the richness and the complexity of the toolkits of the food-producers were positively and significantly influenced by population size in the simple linear regression analyses. The multiple regression analyses demonstrated that these relationships are independent of the effects of risk of resource failure, which is the other main factor that has been found to influence toolkit richness and complexity in nonindustrial groups. Thus, our study strongly suggests that population size influences cultural evolution in nonindustrial food-producing populations. PMID:24069153

  8. Population sizes and group characteristics of Siberian Crane (Leucogeranus leucogeranus) and Hooded Crane (Grus monacha) in Poyang Lake Wetland

    PubMed Central

    SHAO, Ming-Qin; GUO, Hong; JIANG, Jian-Hong

    2014-01-01

    Both the Siberian Crane (Leucogeranus leucogeranus) and Hooded Crane (Grus monacha) have limited population sizes and are considered endangered by domestic Chinese and international agencies. To document the current size of their respective populations and characterize their groups, between October 2012 and April 2013 we undertook fieldwork at four nature reserve areas within the Poyang Lake wetlands. We divided Poyanghu National Nature Reserve (PYH) into the Wucheng (PWC) and Hengfeng areas (PHF), because each are each located in different counties. Our fieldwork showed that the Siberian Crane occurred mainly in PYH (364 in the PHF, 158 in the PWC) and the Nanjishan Wetland National Nature Reserve (NJS, with 200 individuals). The Hooded Crane was mainly distributed in PYH (302 in the PHF and 154 in the PWC). Family groups accounted for more than 50% of the total number of groups among both species, with Hooded Cranes forming more family groups than Siberian Cranes. Typically, these groups were formed of two adults with one offspring (Siberian Crane), and two adults with two offspring (Hooded Crane), with the mean family group size of the Siberian Crane and Hooded Crane being respectively 2.65±0.53 (n=43) and 3.09±0.86 (n=47) individuals per group. The mean collective group size of the Siberian Crane and Hooded Crane included 28.09±24.94 (n=23) and 28.94±27.97 (n=16) individuals per group, respectively, with the proportion of juveniles among Hooded Cranes being more than double that seen among the Siberian Cranes. PMID:25297076

  9. Intermittent breeding and constraints on litter size: consequences for effective population size per generation (Ne ) and per reproductive cycle (Nb ).

    PubMed

    Waples, Robin S; Antao, Tiago

    2014-06-01

    In iteroparous species, it is easier to estimate Nb (effective number of breeders in one reproductive cycle) than Ne (effective population size per generation). Nb can be used as a proxy for Ne and also can provide crucial insights into eco-evolutionary processes that occur during reproduction. We used analytical and numerical methods to evaluate effects of intermittent breeding and litter/clutch size on inbreeding Nb and Ne . Fixed or random litter sizes ≥ 3 have little effect on either effective-size parameter; however, in species (e.g., many large mammals) in which females can produce only one offspring per cycle, female Nb  = ∞ and overall Nb  = 4Nb (male) . Intermittent breeding reduces the pool of female breeders, which reduces both female and overall Nb ; reductions are larger in high-fecundity species with high juvenile mortality and increase when multiple reproductive cycles are skipped. Simulated data for six model species showed that both intermittent breeding and litter-size constraints increase Ne , but only slightly. We show how to quantitatively account for these effects, which are important to consider when (1) using Nb to estimate Ne , or (2) drawing inferences about male reproductive success based on estimates of female Nb . PMID:24611912

  10. Simulation of Micron-Sized Debris Populations in Low Earth Orbit

    NASA Technical Reports Server (NTRS)

    Xu, Y.-L.; Matney, M.; Liou, J.-C.; Hyde, J. L.; Prior, T. G.

    2010-01-01

    The update of ORDEM2000, the NASA Orbital Debris Engineering Model, to its new version . ORDEM2010, is nearly complete. As a part of the ORDEM upgrade, this paper addresses the simulation of micro-debris (greater than 10 micron and smaller than 1 mm in size) populations in low Earth orbit. The principal data used in the modeling of the micron-sized debris populations are in-situ hypervelocity impact records, accumulated in post-flight damage surveys on the space-exposed surfaces of returned spacecrafts. The development of the micro-debris model populations follows the general approach to deriving other ORDEM2010-required input populations for various components and types of debris. This paper describes the key elements and major steps in the statistical inference of the ORDEM2010 micro-debris populations. A crucial step is the construction of a degradation/ejecta source model to provide prior information on the micron-sized objects (such as orbital and object-size distributions). Another critical step is to link model populations with data, which is rather involved. It demands detailed information on area-time/directionality for all the space-exposed elements of a shuttle orbiter and damage laws, which relate impact damage with the physical properties of a projectile and impact conditions such as impact angle and velocity. Also needed are model-predicted debris fluxes as a function of object size and impact velocity from all possible directions. In spite of the very limited quantity of the available shuttle impact data, the population-derivation process is satisfactorily stable. Final modeling results obtained from shuttle window and radiator impact data are reasonably convergent and consistent, especially for the debris populations with object-size thresholds at 10 and 100 micron.

  11. Simulation of Micron-Sized Debris Populations in Low Earth Orbit

    NASA Technical Reports Server (NTRS)

    Xu, Y.-L.; Hyde, J. L.; Prior, T.; Matney, Mark

    2010-01-01

    The update of ORDEM2000, the NASA Orbital Debris Engineering Model, to its new version ORDEM2010, is nearly complete. As a part of the ORDEM upgrade, this paper addresses the simulation of micro-debris (greater than 10 m and smaller than 1 mm in size) populations in low Earth orbit. The principal data used in the modeling of the micron-sized debris populations are in-situ hypervelocity impact records, accumulated in post-flight damage surveys on the space-exposed surfaces of returned spacecrafts. The development of the micro-debris model populations follows the general approach to deriving other ORDEM2010-required input populations for various components and types of debris. This paper describes the key elements and major steps in the statistical inference of the ORDEM2010 micro-debris populations. A crucial step is the construction of a degradation/ejecta source model to provide prior information on the micron-sized objects (such as orbital and object-size distributions). Another critical step is to link model populations with data, which is rather involved. It demands detailed information on area-time/directionality for all the space-exposed elements of a shuttle orbiter and damage laws, which relate impact damage with the physical properties of a projectile and impact conditions such as impact angle and velocity. Also needed are model-predicted debris fluxes as a function of object size and impact velocity from all possible directions. In spite of the very limited quantity of the available shuttle impact data, the population-derivation process is satisfactorily stable. Final modeling results obtained from shuttle window and radiator impact data are reasonably convergent and consistent, especially for the debris populations with object-size thresholds at 10 and 100 m.

  12. Effects of Sample Size on Estimates of Population Growth Rates Calculated with Matrix Models

    PubMed Central

    Fiske, Ian J.; Bruna, Emilio M.; Bolker, Benjamin M.

    2008-01-01

    Background Matrix models are widely used to study the dynamics and demography of populations. An important but overlooked issue is how the number of individuals sampled influences estimates of the population growth rate (λ) calculated with matrix models. Even unbiased estimates of vital rates do not ensure unbiased estimates of λ–Jensen's Inequality implies that even when the estimates of the vital rates are accurate, small sample sizes lead to biased estimates of λ due to increased sampling variance. We investigated if sampling variability and the distribution of sampling effort among size classes lead to biases in estimates of λ. Methodology/Principal Findings Using data from a long-term field study of plant demography, we simulated the effects of sampling variance by drawing vital rates and calculating λ for increasingly larger populations drawn from a total population of 3842 plants. We then compared these estimates of λ with those based on the entire population and calculated the resulting bias. Finally, we conducted a review of the literature to determine the sample sizes typically used when parameterizing matrix models used to study plant demography. Conclusions/Significance We found significant bias at small sample sizes when survival was low (survival = 0.5), and that sampling with a more-realistic inverse J-shaped population structure exacerbated this bias. However our simulations also demonstrate that these biases rapidly become negligible with increasing sample sizes or as survival increases. For many of the sample sizes used in demographic studies, matrix models are probably robust to the biases resulting from sampling variance of vital rates. However, this conclusion may depend on the structure of populations or the distribution of sampling effort in ways that are unexplored. We suggest more intensive sampling of populations when individual survival is low and greater sampling of stages with high elasticities. PMID:18769483

  13. Role of media and peers on body change strategies among adult men: is body size important?

    PubMed

    McCabe, Marita P; McGreevy, Shauna J

    2011-01-01

    There has been limited previous research that has examined the role of sociocultural influences on body change strategies among adult men. The current study investigated the role of specific types of messages (encouragement, teasing and modelling) from peers and the media on the strategies to change weight among adult men. Differences were evaluated between 526 men aged from 18 to 60 years from three groups (normal weight, overweight and obese) on body image, body change strategies and messages about their body received from peers and the media. Men were primarily drawn from United States, Australia and Europe. Results showed that messages received by men regarding losing weight or increasing muscle size differed according to weight. Body image and media messages were the strongest predictors of losing weight, whereas body image importance and messages from peers were the strongest predictors of increasing muscles. These findings highlight the importance of sociocultural influences on body change strategies among adult males.

  14. Flow management and fish density regulate salmonid recruitment and adult size in tailwaters across western North America.

    PubMed

    Dibble, Kimberly L; Yackulic, Charles B; Kennedy, Theodore A; Budy, Phaedra

    2015-12-01

    Rainbow and brown trout have been intentionally introduced into tailwaters downriver of dams globally and provide billions of dollars in economic benefits. At the same time, recruitment and maximum length of trout populations in tailwaters often fluctuate erratically, which negatively affects the value of fisheries. Large recruitment events may increase dispersal downriver where other fish species may be a priority (e.g., endangered species). There is an urgent need to understand the drivers of trout population dynamics in tailwaters, in particular the role of flow management. Here, we evaluate how flow, fish density, and other physical factors of the river influence recruitment and mean adult length in tailwaters across western North America, using data from 29 dams spanning 1-19 years. Rainbow trout recruitment was negatively correlated with high annual, summer, and spring flow and dam latitude, and positively correlated with high winter flow, subadult brown trout catch, and reservoir storage capacity. Brown trout recruitment was negatively correlated with high water velocity and daily fluctuations in flow (i.e., hydropeaking) and positively correlated with adult rainbow trout catch. Among these many drivers, rainbow trout recruitment was primarily correlated with high winter flow combined with low spring flow, whereas brown trout recruitment was most related to high water velocity. The mean lengths of adult rainbow and brown trout were influenced by similar flow and catch metrics. Length in both species was positively correlated with high annual flow but declined in tailwaters with high daily fluctuations in flow, high catch rates of conspecifics, and when large cohorts recruited to adult size. Whereas brown trout did not respond to the proportion of water allocated between seasons, rainbow trout length increased in rivers that released more water during winter than in spring. Rainbow trout length was primarily related to high catch rates of conspecifics

  15. Socio-Economic Instability and the Scaling of Energy Use with Population Size

    PubMed Central

    DeLong, John P.; Burger, Oskar

    2015-01-01

    The size of the human population is relevant to the development of a sustainable world, yet the forces setting growth or declines in the human population are poorly understood. Generally, population growth rates depend on whether new individuals compete for the same energy (leading to Malthusian or density-dependent growth) or help to generate new energy (leading to exponential and super-exponential growth). It has been hypothesized that exponential and super-exponential growth in humans has resulted from carrying capacity, which is in part determined by energy availability, keeping pace with or exceeding the rate of population growth. We evaluated the relationship between energy use and population size for countries with long records of both and the world as a whole to assess whether energy yields are consistent with the idea of an increasing carrying capacity. We find that on average energy use has indeed kept pace with population size over long time periods. We also show, however, that the energy-population scaling exponent plummets during, and its temporal variability increases preceding, periods of social, political, technological, and environmental change. We suggest that efforts to increase the reliability of future energy yields may be essential for stabilizing both population growth and the global socio-economic system. PMID:26091499

  16. When phenology matters: age-size truncation alters population response to trophic mismatch.

    PubMed

    Ohlberger, Jan; Thackeray, Stephen J; Winfield, Ian J; Maberly, Stephen C; Vøllestad, L Asbjørn

    2014-10-22

    Climate-induced shifts in the timing of life-history events are a worldwide phenomenon, and these shifts can de-synchronize species interactions such as predator-prey relationships. In order to understand the ecological implications of altered seasonality, we need to consider how shifts in phenology interact with other agents of environmental change such as exploitation and disease spread, which commonly act to erode the demographic structure of wild populations. Using long-term observational data on the phenology and dynamics of a model predator-prey system (fish and zooplankton in Windermere, UK), we show that age-size truncation of the predator population alters the consequences of phenological mismatch for offspring survival and population abundance. Specifically, age-size truncation reduces intraspecific density regulation due to competition and cannibalism, and thereby amplifies the population sensitivity to climate-induced predator-prey asynchrony, which increases variability in predator abundance. High population variability poses major ecological and economic challenges as it can diminish sustainable harvest rates and increase the risk of population collapse. Our results stress the importance of maintaining within-population age-size diversity in order to buffer populations against phenological asynchrony, and highlight the need to consider interactive effects of environmental impacts if we are to understand and project complex ecological outcomes. PMID:25165767

  17. Socio-Economic Instability and the Scaling of Energy Use with Population Size.

    PubMed

    DeLong, John P; Burger, Oskar

    2015-01-01

    The size of the human population is relevant to the development of a sustainable world, yet the forces setting growth or declines in the human population are poorly understood. Generally, population growth rates depend on whether new individuals compete for the same energy (leading to Malthusian or density-dependent growth) or help to generate new energy (leading to exponential and super-exponential growth). It has been hypothesized that exponential and super-exponential growth in humans has resulted from carrying capacity, which is in part determined by energy availability, keeping pace with or exceeding the rate of population growth. We evaluated the relationship between energy use and population size for countries with long records of both and the world as a whole to assess whether energy yields are consistent with the idea of an increasing carrying capacity. We find that on average energy use has indeed kept pace with population size over long time periods. We also show, however, that the energy-population scaling exponent plummets during, and its temporal variability increases preceding, periods of social, political, technological, and environmental change. We suggest that efforts to increase the reliability of future energy yields may be essential for stabilizing both population growth and the global socio-economic system.

  18. Estimating the Size of Populations at High Risk for HIV Using Respondent-Driven Sampling Data

    PubMed Central

    Handcock, Mark S.; Gile, Krista J.; Mar, Corinne M.

    2015-01-01

    Summary The study of hard-to-reach populations presents significant challenges. Typically, a sampling frame is not available, and population members are difficult to identify or recruit from broader sampling frames. This is especially true of populations at high risk for HIV/AIDS. Respondent-driven sampling (RDS) is often used in such settings with the primary goal of estimating the prevalence of infection. In such populations, the number of people at risk for infection and the number of people infected are of fundamental importance. This article presents a case-study of the estimation of the size of the hard-to-reach population based on data collected through RDS. We study two populations of female sex workers and men-who-have-sex-with-men in El Salvador. The approach is Bayesian and we consider different forms of prior information, including using the UNAIDS population size guidelines for this region. We show that the method is able to quantify the amount of information on population size available in RDS samples. As separate validation, we compare our results to those estimated by extrapolating from a capture–recapture study of El Salvadorian cities. The results of our case-study are largely comparable to those of the capture–recapture study when they differ from the UNAIDS guidelines. Our method is widely applicable to data from RDS studies and we provide a software package to facilitate this. PMID:25585794

  19. Validation of a U.S. Adult Social Self-Efficacy Inventory in Chinese Populations

    ERIC Educational Resources Information Center

    Fan, Jinyan; Meng, Hui; Gao, Xiangping; Lopez, Felix J.; Liu, Cong

    2010-01-01

    The authors report a series of efforts to validate a U.S. adult social self-efficacy inventory, the Perceived Social Self-Efficacy scale (PSSE), in Chinese populations. They argue that the construct underlying the PSSE scale constitutes an important component of Chinese adult social self-efficacy, which was confirmed in focus group discussions.…

  20. The National Blueprint for Promoting Physical Activity in the Mid-Life and Older Adult Population

    ERIC Educational Resources Information Center

    Chodzko-Zajko, Wojtek; Sheppard, Lisa; Senior, Jane; Park, Chae-Hee; Mockenhaupt, Robin; Bazzarre, Terry

    2005-01-01

    The National Blueprint: Increasing Physical Activity Among Adults Age 50 and Older was designed to develop a national strategy for the promotion of physically active lifestyles among the mid-life and older adult population. The Blueprint identifies barriers to physical activity in the areas of research, home and community programs, medical…

  1. Prevalence of Chronic Medical Conditions in Adults with Mental Retardation: Comparison with the General Population.

    ERIC Educational Resources Information Center

    Kapell, Deborah; Nightingale, Beryle; Rodriguez, Ana; Lee, Joseph H.; Zigman, Warren B.; Schupf, Nicole

    1998-01-01

    A study interviewed caregivers and reviewed medical records of 278 adults with mental retardation with and without Down syndrome. The adults with mental retardation had age-related disorders comparable to those in the general population, but there was an increased frequency of thyroid disorders, nonischemic heart disorders, and sensory impairment.…

  2. Does phenotypic plasticity for adult size versus food level in Drosophila melanogaster evolve in response to adaptation to different rearing densities?

    PubMed

    Mueller, Laurence D; Cabral, Larry G

    2012-01-01

    Recent studies with Drosophila have suggested that there is extensive genetic variability for phenotypic plasticity of body size versus food level. If true, we expect that the outcome of evolution at very different food levels should yield genotypes whose adult size show different patterns of phenotypic plasticity. We have tested this prediction with six independent populations of Drosophila melanogaster kept at extreme densities for 125 generations. We found that the phenotypic plasticity of body size versus food level is not affected by selection or the presence of competitors of a different genotype. However, we document increasing among population variation in phenotypic plasticity due to random genetic drift. Several reasons are explored to explain these results including the possibility that the use of highly inbred lines to make inferences about the evolution of genetically variable populations may be misleading.

  3. Population Regulation in Magellanic Penguins: What Determines Changes in Colony Size?

    PubMed Central

    Pozzi, Luciana M.; Borboroglu, Pablo García; Boersma, P. Dee; Pascual, Miguel A.

    2015-01-01

    Seabirds are often studied at individual colonies, but the confounding effects of emigration and mortality processes in open populations may lead to inappropriate conclusions on the mechanisms underlying population changes. Magellanic penguin (Spheniscus magellanicus) colonies of variable population sizes are distributed along the Argentine coastline. In recent decades, several population and distributional changes have occurred, with some colonies declining and others newly established or increasing. We integrated data of eight colonies scattered along ∼ 600 km in Northern Patagonia (from 41°26´S, 65°01´W to 45°11´S, 66°30´W, Rio Negro and Chubut provinces) and conducted analysis in terms of their growth rates, production of young and of the dependence of those vital rates on colony age, size, and location. We contrasted population trends estimated from abundance data with those derived from population modeling to understand if observed growth rates were attainable under closed population scenarios. Population trends were inversely related to colony size, suggesting a density dependent growth pattern. All colonies located in the north—which were established during the last decades—increased at high rates, with the smallest, recently established colonies growing at the fastest rate. In central-southern Chubut, where colonies are the oldest, the largest breeding aggregations declined, but smaller colonies remained relatively stable. Results provided strong evidence that dispersal played a major role in driving local trends. Breeding success was higher in northern colonies, likely mediated by favorable oceanographic conditions. However, mean foraging distance and body condition of chicks at fledging were influenced by colony size. Recruitment of penguins in the northern area may have been triggered by a combination of density dependence, likely exacerbated by less favorable oceanographic conditions in the southern sector. Our results reaffirm the idea

  4. Population regulation in Magellanic penguins: what determines changes in colony size?

    PubMed

    Pozzi, Luciana M; García Borboroglu, Pablo; Boersma, P Dee; Pascual, Miguel A

    2015-01-01

    Seabirds are often studied at individual colonies, but the confounding effects of emigration and mortality processes in open populations may lead to inappropriate conclusions on the mechanisms underlying population changes. Magellanic penguin (Spheniscus magellanicus) colonies of variable population sizes are distributed along the Argentine coastline. In recent decades, several population and distributional changes have occurred, with some colonies declining and others newly established or increasing. We integrated data of eight colonies scattered along ∼600 km in Northern Patagonia (from 41°26´S, 65°01´W to 45°11´S, 66°30´W, Rio Negro and Chubut provinces) and conducted analysis in terms of their growth rates, production of young and of the dependence of those vital rates on colony age, size, and location. We contrasted population trends estimated from abundance data with those derived from population modeling to understand if observed growth rates were attainable under closed population scenarios. Population trends were inversely related to colony size, suggesting a density dependent growth pattern. All colonies located in the north--which were established during the last decades--increased at high rates, with the smallest, recently established colonies growing at the fastest rate. In central-southern Chubut, where colonies are the oldest, the largest breeding aggregations declined, but smaller colonies remained relatively stable. Results provided strong evidence that dispersal played a major role in driving local trends. Breeding success was higher in northern colonies, likely mediated by favorable oceanographic conditions. However, mean foraging distance and body condition of chicks at fledging were influenced by colony size. Recruitment of penguins in the northern area may have been triggered by a combination of density dependence, likely exacerbated by less favorable oceanographic conditions in the southern sector. Our results reaffirm the idea that

  5. Correlates of Suicide in the Older Adult Population in Quebec

    ERIC Educational Resources Information Center

    Preville, Michel; Boyer, Richard; Hebert, Rejean; Bravo, Gina; Seguin, Monique

    2005-01-01

    This study was undertaken to describe the characteristics of adults aged 60 years and over who committed suicide in Quebec in 1998?1999. In this study, 42.6% of the suicide cases presented mental disorders at the time of their death, mainly depression. Sixty-five (65.3%) percent of the suicide cases would have been considered as having a mental…

  6. Alu Insertion Polymorphisms and Human Evolution: Evidence for a Larger Population Size in Africa

    PubMed Central

    Stoneking, Mark; Fontius, Jennifer J.; Clifford, Stephanie L.; Soodyall, Himla; Arcot, Santosh S.; Saha, Nilmani; Jenkins, Trefor; Tahir, Mohammad A.; Deininger, Prescott L.; Batzer, Mark A.

    1997-01-01

    Alu insertion polymorphisms (polymorphisms consisting of the presence/absence of an Alu element at a particular chromosomal location) offer several advantages over other nuclear DNA polymorphisms for human evolution studies. First, they are typed by rapid, simple, PCR-based assays; second, they are stable polymorphisms—newly inserted Alu elements rarely undergo deletion; third, the presence of an Alu element represents identity by descent—the probability that different Alu elements would independently insert into the exact same chromosomal location is negligible; and fourth, the ancestral state is known with certainty to be the absence of an Alu element. We report here a study of 8 loci in 1500 individuals from 34 worldwide populations. African populations exhibit the most between-population differentiation, and the population tree is rooted in Africa; moreover, the estimated effective time of separation of African versus non-African populations is 137,000 ± 15,000 years ago, in accordance with other genetic data. However, a principal coordinates analysis indicates that populations from Sahul (Australia and New Guinea) are nearly as close to the hypothetical ancestor as are African populations, suggesting that there was an early expansion of tropical populations of our species. An analysis of heterozygosity versus genetic distance suggests that African populations have had a larger effective population size than non-African populations. Overall, these results support the African origin of modern humans in that an earlier expansion of the ancestors of African populations is indicated. PMID:9371742

  7. Effects of recruitment, growth, and exploitation on walleye population size structure in northern Wisconsin lakes

    USGS Publications Warehouse

    Hansen, Michael J.; Nate, Nancy A.

    2014-01-01

    We evaluated the dynamics of walleye Sander vitreus population size structure, as indexed by the proportional size distribution (PSD) of quality-length fish, in Escanaba Lake during 1967–2003 and in 204 other lakes in northern Wisconsin during 1990–2011. We estimated PSD from angler-caught walleyes in Escanaba Lake and from spring electrofishing in 204 other lakes, and then related PSD to annual estimates of recruitment to age-3, length at age 3, and annual angling exploitation rate. In Escanaba Lake during 1967–2003, annual estimates of PSD were highly dynamic, growth (positively) explained 35% of PSD variation, recruitment explained only 3% of PSD variation, and exploitation explained only 7% of PSD variation. In 204 other northern Wisconsin lakes during 1990–2011, PSD varied widely among lakes, recruitment (negatively) explained 29% of PSD variation, growth (positively) explained 21% of PSD variation, and exploitation explained only 4% of PSD variation. We conclude that population size structure was most strongly driven by recruitment and growth, rather than exploitation, in northern Wisconsin walleye populations. Studies of other species over wide spatial and temporal ranges of recruitment, growth, and mortality are needed to determine which dynamic rate most strongly influences population size structure of other species. Our findings indicate a need to be cautious about assuming exploitation is a strong driver of walleye population size structure.

  8. Population size vs. social connectedness - A gene-culture coevolutionary approach to cumulative cultural evolution.

    PubMed

    Kobayashi, Yutaka; Ohtsuki, Hisashi; Wakano, Joe Y

    2016-10-01

    It has long been debated if population size is a crucial determinant of the level of culture. While empirical results are mixed, recent theoretical studies suggest that social connectedness between people may be a more important factor than the size of the entire population. These models, however, do not take into account evolutionary responses of learning strategies determining the mode of transmission and innovation and are hence not suitable for predicting the long-term implications of parameters of interest. In the present paper, to address this issue, we provide a gene-culture coevolution model, in which the microscopic learning process of each individual is explicitly described as a continuous-time stochastic process and time allocation to social and individual learning is allowed to evolve. We have found that social connectedness has a larger impact on the equilibrium level of culture than population size especially when connectedness is weak and population size is large. This result, combined with those of previous culture-only models, points to the importance of studying separate effects of population size and internal social structure to better understand spatiotemporal variation in the level of culture. PMID:27402203

  9. Effective Size and F-Statistics of Subdivided Populations. II. Dioecious Species

    PubMed Central

    Wang, J.

    1997-01-01

    For a dioecious diploid population subdivided into an arbitrary number of subpopulations, we have derived recurrence equations for the inbreeding coefficient and coancestries between individuals within and among subpopulations and formulas for effective size and F-statistics. Stable population size and structure, discrete generations, autosomal inheritance, and the island migration model are assumed, and arbitrary distributions of the numbers of male and female progeny per family, different numbers and variable migration rates of males and females are incorporated in our derivation. Some published equations for effective size and F-statistics for a subdivided population are shown to be incorrect because several incorrect probabilities are used in the derivation. A more general equation for effective size is obtained by finding eigenvalue solutions to the recurrence equations for inbreeding coefficient and coancestry in this article, which reduces to the simple and familiar expressions derived by previous authors for the special case of a single unsubdivided population. Our general expressions for F-statistics also reduce to the classical results of WRIGHT's infinite island model and its extensions. It is shown that population structure is important in determining effective size and F-statistics and should be recognized and incorporated into programs for genetic conservation and evolution. PMID:9258688

  10. Population size vs. social connectedness - A gene-culture coevolutionary approach to cumulative cultural evolution.

    PubMed

    Kobayashi, Yutaka; Ohtsuki, Hisashi; Wakano, Joe Y

    2016-10-01

    It has long been debated if population size is a crucial determinant of the level of culture. While empirical results are mixed, recent theoretical studies suggest that social connectedness between people may be a more important factor than the size of the entire population. These models, however, do not take into account evolutionary responses of learning strategies determining the mode of transmission and innovation and are hence not suitable for predicting the long-term implications of parameters of interest. In the present paper, to address this issue, we provide a gene-culture coevolution model, in which the microscopic learning process of each individual is explicitly described as a continuous-time stochastic process and time allocation to social and individual learning is allowed to evolve. We have found that social connectedness has a larger impact on the equilibrium level of culture than population size especially when connectedness is weak and population size is large. This result, combined with those of previous culture-only models, points to the importance of studying separate effects of population size and internal social structure to better understand spatiotemporal variation in the level of culture.

  11. Body size and physical activity levels of adults on Rarotonga, the Cook Islands.

    PubMed

    Ulijaszek, S J

    2001-09-01

    Few studies of physical activity and energy expenditure have been carried out in the Pacific Region. In this study, the physical activity levels (PALs) of adult Cook Islanders living a largely modernised lifestyle by age group and occupation category were determined by a 3 day activity recall diary method. The period of observation included the previous Sunday, as a representative non-working day. A volunteer sample of 332 Cook Islanders aged 22 to 86 years was obtained from the total adult population of Rarotonga. Older adults are significantly less active than younger adults during the working week, but not during the weekend. Males are more physically active than females during the working week, but not on weekends. The mean weekday PAL of males engaged in traditional subsistence or who are unemployed is 1.88, while the mean weekday PAL of females engaged in traditional subsistence or who are housewives is 1.69. Male manual workers have a weekday PAL of 1.96, while female manual workers have a weekday PAL of 1.67. The weekday PAL values for those employed in clerical and administrative work are 1.82 (males) and 1.64 (females), while values for professionals are 1.76 (males) and 1.65 (females). Weekday physical activity is negatively associated with age, in nonlinear fashion. The PALs of adult Cook Islanders living a largely modernised lifestyle is lower in older age groups but does not vary by occupation category. PMID:11517738

  12. Circulating virus load determines the size of bottlenecks in viral populations progressing within a host.

    PubMed

    Gutiérrez, Serafín; Yvon, Michel; Pirolles, Elodie; Garzo, Eliza; Fereres, Alberto; Michalakis, Yannis; Blanc, Stéphane

    2012-01-01

    For any organism, population size, and fluctuations thereof, are of primary importance in determining the forces driving its evolution. This is particularly true for viruses--rapidly evolving entities that form populations with transient and explosive expansions alternating with phases of migration, resulting in strong population bottlenecks and associated founder effects that increase genetic drift. A typical illustration of this pattern is the progression of viral disease within a eukaryotic host, where such demographic fluctuations are a key factor in the emergence of new variants with altered virulence. Viruses initiate replication in one or only a few infection foci, then move through the vasculature to seed secondary infection sites and so invade distant organs and tissues. Founder effects during this within-host colonization might depend on the concentration of infectious units accumulating and circulating in the vasculature, as this represents the infection dose reaching new organs or "territories". Surprisingly, whether or not the easily measurable circulating (plasma) virus load directly drives the size of population bottlenecks during host colonization has not been documented in animal viruses, while in plants the virus load within the sap has never been estimated. Here, we address this important question by monitoring both the virus concentration flowing in host plant sap, and the number of viral genomes founding the population in each successive new leaf. Our results clearly indicate that the concentration of circulating viruses directly determines the size of bottlenecks, which hence controls founder effects and effective population size during disease progression within a host.

  13. Transition Densities and Sample Frequency Spectra of Diffusion Processes with Selection and Variable Population Size

    PubMed Central

    Živković, Daniel; Steinrücken, Matthias; Song, Yun S.; Stephan, Wolfgang

    2015-01-01

    Advances in empirical population genetics have made apparent the need for models that simultaneously account for selection and demography. To address this need, we here study the Wright–Fisher diffusion under selection and variable effective population size. In the case of genic selection and piecewise-constant effective population sizes, we obtain the transition density by extending a recently developed method for computing an accurate spectral representation for a constant population size. Utilizing this extension, we show how to compute the sample frequency spectrum in the presence of genic selection and an arbitrary number of instantaneous changes in the effective population size. We also develop an alternate, efficient algorithm for computing the sample frequency spectrum using a moment-based approach. We apply these methods to answer the following questions: If neutrality is incorrectly assumed when there is selection, what effects does it have on demographic parameter estimation? Can the impact of negative selection be observed in populations that undergo strong exponential growth? PMID:25873633

  14. Circulating virus load determines the size of bottlenecks in viral populations progressing within a host.

    PubMed

    Gutiérrez, Serafín; Yvon, Michel; Pirolles, Elodie; Garzo, Eliza; Fereres, Alberto; Michalakis, Yannis; Blanc, Stéphane

    2012-01-01

    For any organism, population size, and fluctuations thereof, are of primary importance in determining the forces driving its evolution. This is particularly true for viruses--rapidly evolving entities that form populations with transient and explosive expansions alternating with phases of migration, resulting in strong population bottlenecks and associated founder effects that increase genetic drift. A typical illustration of this pattern is the progression of viral disease within a eukaryotic host, where such demographic fluctuations are a key factor in the emergence of new variants with altered virulence. Viruses initiate replication in one or only a few infection foci, then move through the vasculature to seed secondary infection sites and so invade distant organs and tissues. Founder effects during this within-host colonization might depend on the concentration of infectious units accumulating and circulating in the vasculature, as this represents the infection dose reaching new organs or "territories". Surprisingly, whether or not the easily measurable circulating (plasma) virus load directly drives the size of population bottlenecks during host colonization has not been documented in animal viruses, while in plants the virus load within the sap has never been estimated. Here, we address this important question by monitoring both the virus concentration flowing in host plant sap, and the number of viral genomes founding the population in each successive new leaf. Our results clearly indicate that the concentration of circulating viruses directly determines the size of bottlenecks, which hence controls founder effects and effective population size during disease progression within a host. PMID:23133389

  15. Population Variation Reveals Independent Selection toward Small Body Size in Chinese Debao Pony

    PubMed Central

    Kader, Adiljan; Li, Yan; Dong, Kunzhe; Irwin, David M.; Zhao, Qianjun; He, Xiaohong; Liu, Jianfeng; Pu, Yabin; Gorkhali, Neena Amatya; Liu, Xuexue; Jiang, Lin; Li, Xiangchen; Guan, Weijun; Zhang, Yaping; Wu, Dong-Dong; Ma, Yuehui

    2016-01-01

    Body size, one of the most important quantitative traits under evolutionary scrutiny, varies considerably among species and among populations within species. Revealing the genetic basis underlying this variation is very important, particularly in humans where there is a close relationship with diseases and in domestic animals as the selective patterns are associated with improvements in production traits. The Debao pony is a horse breed with small body size that is unique to China; however, it is unknown whether the size-related candidate genes identified in Western breeds also account for the small body size of the Debao pony. Here, we compared individual horses from the Debao population with other two Chinese horse populations using single nucleotide polymorphisms (SNPs) identified with the Equine SNP 65 Bead Chip. The previously reported size-related candidate gene HMGA2 showed a significant signature for selection, consistent with its role observed in human populations. More interestingly, we found a candidate gene TBX3, which had not been observed in previous studies on horse body size that displayed the highest differentiation and most significant association, and thus likely is the dominating factor for the small stature of the Debao pony. Further comparison between the Debao pony and other breeds of horses from around the world demonstrated that TBX3 was selected independently in the Debao pony, suggesting that there were multiple origins of small stature in the horse. PMID:26637467

  16. Busulfan in infants to adult hematopoietic cell transplant recipients: A population pharmacokinetic model for initial and Bayesian dose personalization

    PubMed Central

    McCune, Jeannine S.; Bemer, Meagan J.; Barrett, Jeffrey S.; Baker, K. Scott; Gamis, Alan S.; Holford, Nicholas H.G.

    2014-01-01

    Purpose Personalizing intravenous (IV) busulfan doses to a target plasma concentration at steady state (Css) is an essential component of hematopoietic cell transplantation (HCT). We sought to develop a population pharmacokinetic model to predict IV busulfan doses over a wide age spectrum (0.1 – 66 years) that accounts for differences in age and body size. Experimental design A population pharmacokinetic model based on normal fat mass and maturation based on post-menstrual age was built from 12,380 busulfan concentration-time points obtained after IV busulfan administration in 1,610 HCT recipients. Subsequently, simulation results of the initial dose necessary to achieve a target Css with this model were compared with pediatric-only models. Results A two-compartment model with first-order elimination best fit the data. The population busulfan clearance was 12.4 L/h for an adult male with 62kg normal fat mass (equivalent to 70kg total body weight). Busulfan clearance, scaled to body size – specifically normal fat mass, is predicted to be 95% of the adult clearance at 2.5 years post-natal age. With a target Css of 770 ng/mL, a higher proportion of initial doses achieved the therapeutic window with this age- and size-dependent model (72%) compared to dosing recommended by the Food and Drug Administration (57%) or the European Medicines Agency (70%). Conclusion This is the first population pharmacokinetic model developed to predict initial IV busulfan doses and personalize to a target Css over a wide age spectrum, ranging from infants to adults. PMID:24218510

  17. Size-frequency distribution of crater populations in equilibrium on the Moon

    NASA Astrophysics Data System (ADS)

    Xiao, Zhiyong; Werner, Stephanie C.

    2015-12-01

    Overprinting of craters by subsequent impacts and topographic degradation complicates crater statistics, especially for old surfaces and small-diameter crater populations. A crater population is regarded as in equilibrium at a particular crater size when smaller craters are being produced at the same rate at which they are being destroyed. Evaluating the equilibrium state of crater populations is challenging, and empirical equilibrium densities are frequently inferred. By performing careful crater counts and cross comparisons on several lunar surfaces, we study the size-frequency distributions (SFD) for the crater populations, which have portions in equilibrium. The results are one of the few observational constraints on the SFD of crater populations in equilibrium, showing that referring to empirical equilibrium densities is not safe for evaluating the equilibrium states of crater populations. Equilibrium densities are not positively correlated with the ages of crater populations, and some populations in equilibrium have crater densities less than those previously believed to represent equilibrium conditions. Besides the SFD of the production population, different crater removal rates at different diameters also affect the SFD of crater populations in equilibrium. The equilibrium onset diameter (Deq) of a crater population can be translated to model ages because older populations have larger Deq, and those for same-aged surfaces are comparable. We show that the crater populations studied here are in equilibrium at much smaller diameters than those predicted for same-aged surfaces by crater degradation models, thus indicating lower crater degradation rates on the Moon, and/or younger ages of the counting areas.

  18. Children and Adults Use Physical Size and Numerical Alliances in Third-Party Judgments of Dominance

    PubMed Central

    Lourenco, Stella F.; Bonny, Justin W.; Schwartz, Bari L.

    2016-01-01

    Humans and other social animals interact regularly with conspecifics as part of affiliative groups. Many of these interactions are cooperative, but many others involve competition for resources. Competitive exchanges are often resolved on the basis of dominance relationships, with higher-ranking individuals receiving priority access to desired goods. Although no single cue can establish permanent dominance relationships, there are some cues that predict dominance fairly reliably across context. In the present study, we focused on two such cues relevant to competing groups: (i) the physical sizes of individual members, and (ii) their relative number. Using a social competition task, we examined whether, and how, preschool-aged children and adults used differences in physical size and numerical alliances to judge which of two groups should prevail in a competitive exchange for a desired object. These judgments were made when either physical size or number differed between groups (Experiment 1), and when both were available but pitted against each other (Experiments 1 and 2). Our findings revealed that by 3 years of age, humans use multiple perceptible cues in third-party judgments of dominance. Our findings also revealed that 3-year-olds, like adults, weighted these cues flexibly according to the additional factor of overall group size, with the physical sizes of individuals determining dominance in smaller groups (e.g., 2 vs. 4 characters) and the relative number of individuals determining dominance in larger groups (e.g., 15 vs. 30 characters). Taken together, our findings suggest that a basic formula for determining dominance in competitive exchanges, which weights physical size of individuals and numerical alliances as a function of overall group size, is available to young children and appears fairly stable through to adulthood. PMID:26793158

  19. Well-Being in an Adult Swedish Population

    ERIC Educational Resources Information Center

    Hansson, Anna; Hilleras, Pernilla; Forsell, Yvonne

    2005-01-01

    Objectives: The aim of this study was to see if earlier findings about factors associated with well-being could be replicated in a large population-based sample in Sweden. To the best of our knowledge, no research on well-being has been conducted on such a large population in a country, which by most standards is regarded as one of the most…

  20. Population size estimation in Yellowstone wolves with error-prone noninvasive microsatellite genotypes.

    PubMed

    Creel, Scott; Spong, Goran; Sands, Jennifer L; Rotella, Jay; Zeigle, Janet; Joe, Lawrence; Murphy, Kerry M; Smith, Douglas

    2003-07-01

    Determining population sizes can be difficult, but is essential for conservation. By counting distinct microsatellite genotypes, DNA from noninvasive samples (hair, faeces) allows estimation of population size. Problems arise because genotypes from noninvasive samples are error-prone, but genotyping errors can be reduced by multiple polymerase chain reaction (PCR). For faecal genotypes from wolves in Yellowstone National Park, error rates varied substantially among samples, often above the 'worst-case threshold' suggested by simulation. Consequently, a substantial proportion of multilocus genotypes held one or more errors, despite multiple PCR. These genotyping errors created several genotypes per individual and caused overestimation (up to 5.5-fold) of population size. We propose a 'matching approach' to eliminate this overestimation bias. PMID:12803649

  1. Correlation between diet and gut bacteria in a population of young adults.

    PubMed

    Mayorga Reyes, Lino; González Vázquez, Raquel; Cruz Arroyo, Schahrasad M; Melendez Avalos, Araceli; Reyes Castillo, Pedro A; Chavaro Pérez, David A; Ramos Terrones, Idalia; Ramos Ibáñez, Norma; Rodríguez Magallanes, Magdalena M; Langella, Philippe; Bermúdez Humarán, Luis; Azaola Espinosa, Alejandro

    2016-06-01

    Dietary habits strongly influence gut microbiota. The aim of this study was to compare and correlated the abundance of Firmicutes and Bacteroidetes phyla, some representative bacteria of these phyla such as Bacteroides thetaiotaomicron, Prevotella, Faecalibacterium prausnitzii, Clostridium leptum and Bifidobacterium longum as a member of Actinobacteria phylum in young adults with their food intake. Faecal samples used came from lean subjects (BMI = 19.83 ± 0.94 kg/m(2)), overweight (BMI = 27.17 ± 0.51 kg/m(2)) and obese (BMI = 41.33 ± 5.25 kg/m(2)). There were significant differences in total studied gut microbiota between the overweight and lean groups. Members of the Firmicutes phylum, and Bifidobacterium longum, were more abundant in the lean group. The results suggest that diet rich in unsaturated fatty acids and fibre promote an abundant population of beneficial bacteria such as B. longum and Bacteroidetes. However, it has been considered that the results may be biased due to the size of the individuals studied; therefore the results could be only valid for the studied population.

  2. Correlation between diet and gut bacteria in a population of young adults.

    PubMed

    Mayorga Reyes, Lino; González Vázquez, Raquel; Cruz Arroyo, Schahrasad M; Melendez Avalos, Araceli; Reyes Castillo, Pedro A; Chavaro Pérez, David A; Ramos Terrones, Idalia; Ramos Ibáñez, Norma; Rodríguez Magallanes, Magdalena M; Langella, Philippe; Bermúdez Humarán, Luis; Azaola Espinosa, Alejandro

    2016-06-01

    Dietary habits strongly influence gut microbiota. The aim of this study was to compare and correlated the abundance of Firmicutes and Bacteroidetes phyla, some representative bacteria of these phyla such as Bacteroides thetaiotaomicron, Prevotella, Faecalibacterium prausnitzii, Clostridium leptum and Bifidobacterium longum as a member of Actinobacteria phylum in young adults with their food intake. Faecal samples used came from lean subjects (BMI = 19.83 ± 0.94 kg/m(2)), overweight (BMI = 27.17 ± 0.51 kg/m(2)) and obese (BMI = 41.33 ± 5.25 kg/m(2)). There were significant differences in total studied gut microbiota between the overweight and lean groups. Members of the Firmicutes phylum, and Bifidobacterium longum, were more abundant in the lean group. The results suggest that diet rich in unsaturated fatty acids and fibre promote an abundant population of beneficial bacteria such as B. longum and Bacteroidetes. However, it has been considered that the results may be biased due to the size of the individuals studied; therefore the results could be only valid for the studied population. PMID:27018166

  3. Dissociative Symptoms and Mother's Marital Status in Young Adult Population

    PubMed Central

    Bob, Petr; Selesova, Petra; Raboch, Jiri; Kukla, Lubomir

    2015-01-01

    Abstract Current findings suggest that mother's marital status indicating father's absence or conflicting relationship to father may be specifically related to dissociation and other stress-related symptoms. We have assessed relationships of mother's marital status, dissociative symptoms, and other psychopathological manifestations in a sample of 19 years’ old young adults (N = 364) participating in European longitudinal study (European Longitudinal Study of Parenthood and Childhood). The results show clinically significant manifestations of dissociative symptoms in young adult men whose mothers were fatherless and in women whose mothers were re-married. Other psychopathological symptoms did not reach clinically significant manifestations. The results suggest that significant factor related to high level of dissociative symptoms in men growing in fatherless families might be linked with disturbed and conflicting attachment to a father's figure and pathological dependent attachment to mother. In women dissociative symptoms likely are linked to conflicting relationship between mother and daughter associated with stepfather’ presence in the family. PMID:25590849

  4. Optimising inhaled mannitol for cystic fibrosis in an adult population

    PubMed Central

    Flume, Patrick A.; Aitken, Moira L.; Agent, Penny; Charlton, Brett; Forster, Emma; Fox, Howard G.; Hebestreit, Helge; Kolbe, John; Zuckerman, Jonathan B; Button, Brenda M.

    2015-01-01

    Abstract There has been remarkable progress in the treatment of cystic fibrosis (CF) patients over the past 20 years. However, limitations of standard therapies have highlighted the need for a convenient alternative treatment to effectively target the pathophysiologic basis of CF-related disease by improving mucociliary clearance of airway secretions and consequently improve lung function and reduce respiratory exacerbations. Mannitol is an osmotic agent available as a dry powder, dispensed in a convenient disposable inhaler device for the treatment of adult patients with CF. Inhalation of mannitol as a dry powder is thought to change the viscoelastic properties of airway secretions, increase the hydration of the airway surface liquid and contribute to increased mucociliary and cough clearance of retained secretions. In two large phase 3 studies [1, 2], long-term use of inhaled mannitol resulted in a significant and clinically meaningful improvement in lung function relative to control in adult CF subjects and had an acceptable safety profile. Clinical experience with inhaled mannitol confirms that it is safe and effective. A minority of patients are unable to tolerate the medication. However, through training in proper inhaler technique and setting clear expectations regarding therapeutic effects, both the tolerance and adherence necessary for long term efficacy can be positively influenced. Educational aims To discuss the importance of airway clearance treatments in the management of cystic fibrosis. To describe the clinical data that supports the use of mannitol in adult patients with cystic fibrosis. To highlight the role of mannitol tolerance testing in screening for hyperresponsiveness. To provide practical considerations for patient education in use of mannitol inhaler. Key points Inhaled mannitol is a safe and effective option in adult patients with cystic fibrosis. Mannitol tolerance testing effectively screens for hyperresponsiveness prior to initiation

  5. Grammatical Class Effects Across Impaired Child and Adult Populations.

    PubMed

    Kambanaros, Maria; Grohmann, Kleanthes K

    2015-01-01

    The aims of this study are to compare quantitative and qualitative differences for noun/verb retrieval across language-impaired groups, examine naming errors with reference to psycholinguistic models of word processing, and shed light on the nature of the naming deficit as well as determine relevant group commonalities and differences. This includes an attempt to establish whether error types differentiate language-impaired children from adults, to determine effects of psycholinguistic variables on naming accuracies, and to link the results to genetic mechanisms and/or neural circuitry in the brain. A total of 89 (language-)impaired participants took part in this report: 24 adults with acquired aphasia, 20 adults with schizophrenia-spectrum disorder, 31 adults with relapsing-remitting multiple sclerosis, and 14 children with specific language impairment. The results of simultaneous multiple regression analyses for the errors in verb naming compared to the psycholinguistic variables for all language-impaired groups are reported and discussed in relation to models of lexical processing. This discussion will lead to considerations of genetic and/or neurobiological underpinnings: Presence of the noun-verb dissociation in focal and non-focal brain impairment make localization theories redundant, but support for wider neural network involvement.The patterns reported cannot be reduced to any one level of language processing, suggesting multiple interactions at different levels (e.g., receptive vs. expressive language abilities).Semantic-conceptual properties constrain syntactic properties with implications for phonological word form retrieval.Competition needs to be resolved at both conceptual and phonological levels of representation. Moreover, this study may provide a cross-pathological baseline that can be probed further with respect to recent suggestions concerning a reconsideration of open- vs. closed-class items, according to which verbs may actually fall into the

  6. Grammatical Class Effects Across Impaired Child and Adult Populations

    PubMed Central

    Kambanaros, Maria; Grohmann, Kleanthes K.

    2015-01-01

    The aims of this study are to compare quantitative and qualitative differences for noun/verb retrieval across language-impaired groups, examine naming errors with reference to psycholinguistic models of word processing, and shed light on the nature of the naming deficit as well as determine relevant group commonalities and differences. This includes an attempt to establish whether error types differentiate language-impaired children from adults, to determine effects of psycholinguistic variables on naming accuracies, and to link the results to genetic mechanisms and/or neural circuitry in the brain. A total of 89 (language-)impaired participants took part in this report: 24 adults with acquired aphasia, 20 adults with schizophrenia-spectrum disorder, 31 adults with relapsing-remitting multiple sclerosis, and 14 children with specific language impairment. The results of simultaneous multiple regression analyses for the errors in verb naming compared to the psycholinguistic variables for all language-impaired groups are reported and discussed in relation to models of lexical processing. This discussion will lead to considerations of genetic and/or neurobiological underpinnings: Presence of the noun–verb dissociation in focal and non-focal brain impairment make localization theories redundant, but support for wider neural network involvement.The patterns reported cannot be reduced to any one level of language processing, suggesting multiple interactions at different levels (e.g., receptive vs. expressive language abilities).Semantic-conceptual properties constrain syntactic properties with implications for phonological word form retrieval.Competition needs to be resolved at both conceptual and phonological levels of representation. Moreover, this study may provide a cross-pathological baseline that can be probed further with respect to recent suggestions concerning a reconsideration of open- vs. closed-class items, according to which verbs may actually fall into the

  7. Host Plant Determines the Population Size of an Obligate Symbiont (Buchnera aphidicola) in Aphids.

    PubMed

    Zhang, Yuan-Chen; Cao, Wen-Jie; Zhong, Le-Rong; Godfray, H Charles J; Liu, Xiang-Dong

    2016-04-01

    Buchnera aphidicolais an obligate endosymbiont that provides aphids with several essential nutrients. Though much is known about aphid-Buchnera interactions, the effect of the host plant on Buchnera population size remains unclear. Here we used quantitative PCR (qPCR) techniques to explore the effects of the host plant on Buchnera densities in the cotton-melon aphid, Aphis gossypii Buchneratiters were significantly higher in populations that had been reared on cucumber for over 10 years than in populations maintained on cotton for a similar length of time. Aphids collected in the wild from hibiscus and zucchini harbored more Buchnera symbionts than those collected from cucumber and cotton. The effect of aphid genotype on the population size of Buchnera depended on the host plant upon which they fed. When aphids from populations maintained on cucumber or cotton were transferred to novel host plants, host survival and Buchnera population size fluctuated markedly for the first two generations before becoming relatively stable in the third and later generations. Host plant extracts from cucumber, pumpkin, zucchini, and cowpea added to artificial diets led to a significant increase in Buchnera titers in the aphids from the population reared on cotton, while plant extracts from cotton and zucchini led to a decrease in Buchnera titers in the aphids reared on cucumber. Gossypol, a secondary metabolite from cotton, suppressed Buchnera populations in populations from both cotton and cucumber, while cucurbitacin from cucurbit plants led to higher densities. Together, the results suggest that host plants influence Buchnera population processes and that this may provide phenotypic plasticity in host plant use for clonal aphids. PMID:26850304

  8. Host Plant Determines the Population Size of an Obligate Symbiont (Buchnera aphidicola) in Aphids

    PubMed Central

    Zhang, Yuan-Chen; Cao, Wen-Jie; Zhong, Le-Rong; Godfray, H. Charles J.

    2016-01-01

    Buchnera aphidicola is an obligate endosymbiont that provides aphids with several essential nutrients. Though much is known about aphid-Buchnera interactions, the effect of the host plant on Buchnera population size remains unclear. Here we used quantitative PCR (qPCR) techniques to explore the effects of the host plant on Buchnera densities in the cotton-melon aphid, Aphis gossypii. Buchnera titers were significantly higher in populations that had been reared on cucumber for over 10 years than in populations maintained on cotton for a similar length of time. Aphids collected in the wild from hibiscus and zucchini harbored more Buchnera symbionts than those collected from cucumber and cotton. The effect of aphid genotype on the population size of Buchnera depended on the host plant upon which they fed. When aphids from populations maintained on cucumber or cotton were transferred to novel host plants, host survival and Buchnera population size fluctuated markedly for the first two generations before becoming relatively stable in the third and later generations. Host plant extracts from cucumber, pumpkin, zucchini, and cowpea added to artificial diets led to a significant increase in Buchnera titers in the aphids from the population reared on cotton, while plant extracts from cotton and zucchini led to a decrease in Buchnera titers in the aphids reared on cucumber. Gossypol, a secondary metabolite from cotton, suppressed Buchnera populations in populations from both cotton and cucumber, while cucurbitacin from cucurbit plants led to higher densities. Together, the results suggest that host plants influence Buchnera population processes and that this may provide phenotypic plasticity in host plant use for clonal aphids. PMID:26850304

  9. Host Plant Determines the Population Size of an Obligate Symbiont (Buchnera aphidicola) in Aphids.

    PubMed

    Zhang, Yuan-Chen; Cao, Wen-Jie; Zhong, Le-Rong; Godfray, H Charles J; Liu, Xiang-Dong

    2016-04-01

    Buchnera aphidicolais an obligate endosymbiont that provides aphids with several essential nutrients. Though much is known about aphid-Buchnera interactions, the effect of the host plant on Buchnera population size remains unclear. Here we used quantitative PCR (qPCR) techniques to explore the effects of the host plant on Buchnera densities in the cotton-melon aphid, Aphis gossypii Buchneratiters were significantly higher in populations that had been reared on cucumber for over 10 years than in populations maintained on cotton for a similar length of time. Aphids collected in the wild from hibiscus and zucchini harbored more Buchnera symbionts than those collected from cucumber and cotton. The effect of aphid genotype on the population size of Buchnera depended on the host plant upon which they fed. When aphids from populations maintained on cucumber or cotton were transferred to novel host plants, host survival and Buchnera population size fluctuated markedly for the first two generations before becoming relatively stable in the third and later generations. Host plant extracts from cucumber, pumpkin, zucchini, and cowpea added to artificial diets led to a significant increase in Buchnera titers in the aphids from the population reared on cotton, while plant extracts from cotton and zucchini led to a decrease in Buchnera titers in the aphids reared on cucumber. Gossypol, a secondary metabolite from cotton, suppressed Buchnera populations in populations from both cotton and cucumber, while cucurbitacin from cucurbit plants led to higher densities. Together, the results suggest that host plants influence Buchnera population processes and that this may provide phenotypic plasticity in host plant use for clonal aphids.

  10. Metapopulation effective size and conservation genetic goals for the Fennoscandian wolf (Canis lupus) population.

    PubMed

    Laikre, L; Olsson, F; Jansson, E; Hössjer, O; Ryman, N

    2016-10-01

    The Scandinavian wolf population descends from only five individuals, is isolated, highly inbred and exhibits inbreeding depression. To meet international conservation goals, suggestions include managing subdivided wolf populations over Fennoscandia as a metapopulation; a genetically effective population size of Ne⩾500, in line with the widely accepted long-term genetic viability target, might be attainable with gene flow among subpopulations of Scandinavia, Finland and Russian parts of Fennoscandia. Analytical means for modeling Ne of subdivided populations under such non-idealized situations have been missing, but we recently developed new mathematical methods for exploring inbreeding dynamics and effective population size of complex metapopulations. We apply this theory to the Fennoscandian wolves using empirical estimates of demographic parameters. We suggest that the long-term conservation genetic target for metapopulations should imply that inbreeding rates in the total system and in the separate subpopulations should not exceed Δf=0.001. This implies a meta-Ne of NeMeta⩾500 and a realized effective size of each subpopulation of NeRx⩾500. With current local effective population sizes and one migrant per generation, as recommended by management guidelines, the meta-Ne that can be reached is ~250. Unidirectional gene flow from Finland to Scandinavia reduces meta-Ne to ~130. Our results indicate that both local subpopulation effective sizes and migration among subpopulations must increase substantially from current levels to meet the conservation target. Alternatively, immigration from a large (Ne⩾500) population in northwestern Russia could support the Fennoscandian metapopulation, but immigration must be substantial (5-10 effective immigrants per generation) and migration among Fennoscandian subpopulations must nevertheless increase. PMID:27328654

  11. Metapopulation effective size and conservation genetic goals for the Fennoscandian wolf (Canis lupus) population

    PubMed Central

    Laikre, L; Olsson, F; Jansson, E; Hössjer, O; Ryman, N

    2016-01-01

    The Scandinavian wolf population descends from only five individuals, is isolated, highly inbred and exhibits inbreeding depression. To meet international conservation goals, suggestions include managing subdivided wolf populations over Fennoscandia as a metapopulation; a genetically effective population size of Ne⩾500, in line with the widely accepted long-term genetic viability target, might be attainable with gene flow among subpopulations of Scandinavia, Finland and Russian parts of Fennoscandia. Analytical means for modeling Ne of subdivided populations under such non-idealized situations have been missing, but we recently developed new mathematical methods for exploring inbreeding dynamics and effective population size of complex metapopulations. We apply this theory to the Fennoscandian wolves using empirical estimates of demographic parameters. We suggest that the long-term conservation genetic target for metapopulations should imply that inbreeding rates in the total system and in the separate subpopulations should not exceed Δf=0.001. This implies a meta-Ne of NeMeta⩾500 and a realized effective size of each subpopulation of NeRx⩾500. With current local effective population sizes and one migrant per generation, as recommended by management guidelines, the meta-Ne that can be reached is ~250. Unidirectional gene flow from Finland to Scandinavia reduces meta-Ne to ~130. Our results indicate that both local subpopulation effective sizes and migration among subpopulations must increase substantially from current levels to meet the conservation target. Alternatively, immigration from a large (Ne⩾500) population in northwestern Russia could support the Fennoscandian metapopulation, but immigration must be substantial (5–10 effective immigrants per generation) and migration among Fennoscandian subpopulations must nevertheless increase. PMID:27328654

  12. The genetics of rhizosheath size in a multiparent mapping population of wheat

    PubMed Central

    Delhaize, Emmanuel; Rathjen, Tina M.; Cavanagh, Colin R.

    2015-01-01

    Rhizosheaths comprise soil that adheres to plant roots and, in some species, are indicative of root hair length. In this study, the genetics of rhizosheath size in wheat was investigated by screening the progeny of multiparent advanced generation intercrosses (MAGIC). Two MAGIC populations were screened for rhizosheath size using a high throughput method. One MAGIC population was developed from intercrosses between four parents (4-way) and the other from intercrosses between eight parents (8-way). Transgressive segregation for rhizosheath size was observed in both the 4-way and 8-way MAGIC populations. A quantitative trait loci (QTL) analysis of the 4-way population identified six major loci located on chromosomes 2B, 4D, 5A, 5B, 6A, and 7A together accounting for 42% of the variation in rhizosheath size. Rhizosheath size was strongly correlated with root hair length and was robust across different soil types in the absence of chemical constraints. Rhizosheath size in the MAGIC populations was a reliable surrogate for root hair length and, therefore, the QTL identified probably control root hair elongation. Members of the basic helix-loop-helix family of transcription factors have previously been identified to regulate root hair length in Arabidopsis and rice. Since several wheat members of the basic helix-loop-helix family of genes are located within or near the QTL, these genes are candidates for controlling the long root hair trait. The QTL for rhizosheath size identified in this study provides the opportunity to implement marker-assisted selection to increase root hair length for improved phosphate acquisition in wheat. PMID:25969556

  13. Only a small population of adult Sertoli cells actively proliferates in culture.

    PubMed

    Kulibin, Andrey Yu; Malolina, Ekaterina A

    2016-10-01

    Adult mammalian Sertoli cells (SCs) have been considered to be quiescent terminal differentiated cells for many years, but recently, proliferation of adult SCs was demonstrated in vitro and in vivo We further examined mouse SC behavior in culture and found that there are two populations of adult SCs. The first population is SCs from seminiferous tubules that hardly proliferate in vitro The second population is small and consists of SCs with atypical nuclear morphology from the terminal segments of seminiferous tubules, a transitional zone (TZ). TZ SCs multiply in culture and form colonies, display mixture of mature and immature SC characteristics, and generate cord-like structures in a collagen matrix. The specific features of TZ SCs are ACTA2 expression in vitro and DMRT1 low levels in vivo and in vitro Although the in vivo function of TZ SCs still remains unclear, this finding has significant implications for our understanding of SC differentiation and functioning in adult mammals.

  14. Nautilus at risk--estimating population size and demography of Nautilus pompilius.

    PubMed

    Dunstan, Andrew; Bradshaw, Corey J A; Marshall, Justin

    2011-02-10

    The low fecundity, late maturity, long gestation and long life span of Nautilus suggest that this species is vulnerable to over-exploitation. Demand from the ornamental shell trade has contributed to their rapid decline in localized populations. More data from wild populations are needed to design management plans which ensure Nautilus persistence. We used a variety of techniques including capture-mark-recapture, baited remote underwater video systems, ultrasonic telemetry and remotely operated vehicles to estimate population size, growth rates, distribution and demographic characteristics of an unexploited Nautilus pompilius population at Osprey Reef (Coral Sea, Australia). We estimated a small and dispersed population of between 844 and 4467 individuals (14.6-77.4 km(-2)) dominated by males (83:17 male:female) and comprised of few juveniles (<10%).These results provide the first Nautilid population and density estimates which are essential elements for long-term management of populations via sustainable catch models. Results from baited remote underwater video systems provide confidence for their more widespread use to assess efficiently the size and density of exploited and unexploited Nautilus populations worldwide.

  15. Nautilus at Risk – Estimating Population Size and Demography of Nautilus pompilius

    PubMed Central

    Dunstan, Andrew; Bradshaw, Corey J. A.; Marshall, Justin

    2011-01-01

    The low fecundity, late maturity, long gestation and long life span of Nautilus suggest that this species is vulnerable to over-exploitation. Demand from the ornamental shell trade has contributed to their rapid decline in localized populations. More data from wild populations are needed to design management plans which ensure Nautilus persistence. We used a variety of techniques including capture-mark-recapture, baited remote underwater video systems, ultrasonic telemetry and remotely operated vehicles to estimate population size, growth rates, distribution and demographic characteristics of an unexploited Nautilus pompilius population at Osprey Reef (Coral Sea, Australia). We estimated a small and dispersed population of between 844 and 4467 individuals (14.6–77.4 km−2) dominated by males (83∶17 male∶female) and comprised of few juveniles (<10%).These results provide the first Nautilid population and density estimates which are essential elements for long-term management of populations via sustainable catch models. Results from baited remote underwater video systems provide confidence for their more widespread use to assess efficiently the size and density of exploited and unexploited Nautilus populations worldwide. PMID:21347360

  16. Increased Selection Response in Larger Populations. II. Selection for Ethanol Vapor Resistance in Drosophila Melanogaster at Two Population Sizes

    PubMed Central

    Weber, K. E.; Diggins, L. T.

    1990-01-01

    The effect of large population size on selection response was investigated using Drosophila melanogaster, with four ``small'' lines of 160 selected parents/generation compared to two ``large'' lines of 1600 selected parents/generation. All lines were selected under similar conditions at a selection intensity of approximately 0.55 standard deviations, for 65 generations, for increased ethanol vapor resistance (measured in minutes required to become anesthetized). Two unselected control lines of 320 parents/generation were also maintained. A significant effect of population size was found. The final treatment means and standard errors were: 27.91 +/- 1.28 min (two ``large'' lines); 19.40 +/- 1.54 min (four ``small'' lines); and 4.98 +/- 0.35 min (two control lines). To estimate the mutation rate for the trait, two isogenic lines of about 400 selected parents were selected for 29 generations. The mean increase in additive genetic variance per generation was 0.0009 times the initial environmental variance of the outbred lines. This is comparable to other reported mutation rates. Mutation can explain part of the difference in evolved resistance between treatments, but it appears that even at rather large population sizes, a large difference in long-term response can be obtained in larger outbred lines, from more complete utilization of the initial genetic variation. PMID:2116359

  17. Linkage Disequilibrium Estimation of Effective Population Size with Immigrants from Divergent Populations: A Case Study on Spanish Mackerel (Scomberomorus commerson).

    PubMed

    Macbeth, Gilbert Michael; Broderick, Damien; Buckworth, Rik C; Ovenden, Jennifer R

    2013-03-11

    Estimates of genetic effective population size (Ne) using molecular markers are a potentially useful tool for the management of endangered through to commercial species. But, pitfalls are predicted when the effective size is large, as estimates require large numbers of samples from wild populations for statistical validity. Our simulations showed that linkage disequilibrium estimates of Ne up to 10,000 with finite confidence limits can be achieved with sample sizes around 5000. This was deduced from empirical allele frequencies of seven polymorphic microsatellite loci in a commercially harvested fisheries species, the narrow barred Spanish mackerel (Scomberomorus commerson). As expected, the smallest standard deviation of Ne estimates occurred when low frequency alleles were excluded. Additional simulations indicated that the linkage disequilibrium method was sensitive to small numbers of genotypes from cryptic species or conspecific immigrants. A correspondence analysis algorithm was developed to detect and remove outlier genotypes that could possibly be inadvertently sampled from cryptic species or non-breeding immigrants from genetically separate populations. Simulations demonstrated the value of this approach in Spanish mackerel data. When putative immigrants were removed from the empirical data, 95% of the Ne estimates from jacknife resampling were above 24,000.

  18. Size-dependent mortality induces life-history changes mediated through population dynamical feedbacks.

    PubMed

    van Kooten, Tobias; Persson, Lennart; de Roos, André M

    2007-08-01

    The majority of taxa grow significantly during life history, which often leads to individuals of the same species having different ecological roles, depending on their size or life stage. One aspect of life history that changes during ontogeny is mortality. When individual growth and development are resource dependent, changes in mortality can affect the outcome of size-dependent intraspecific resource competition, in turn affecting both life history and population dynamics. We study the outcome of varying size-dependent mortality on two life-history types, one that feeds on the same resource throughout life history and another that can alternatively cannibalize smaller conspecifics. Compensatory responses in the life history dampen the effect of certain types of size-dependent mortality, while other types of mortality lead to dramatic changes in life history and population dynamics, including population (de-)stabilization, and the growth of cannibalistic giants. These responses differ strongly among the two life-history types. Our analysis provides a mechanistic understanding of the population-level effects that come about through the interaction between individual growth and size-dependent mortality, mediated by resource dependence in individual vital rates. PMID:17874376

  19. Impact of population size on market demand under a market economy.

    PubMed

    Li, Y

    1996-01-01

    This article presents an analysis of the relationship between population size and market demand in China. It is argued that a smaller elasticity of a product is related to a greater impact of the size of population on the consumption of such a product. Greater elasticity reduces the impact of population. The impact of population is also mediated by average salary and salary structure. Salary structure affects prices, and prices affect supply and demand, which affect consumption. In a market-oriented economic system, the impact of population size on market demand affects supply and demand and prices. Current market demand reflects the effect of supply and demand in previous periods. Current population size will affect future market demand through prices and supply elasticity. Population changes are slow, and consumption changes are slow. The slowness of the process of change means there is time to adjust production and distribution in order to achieve stability in market supply. Control of price increases and inflation will promote economic growth, social stability, and improvement in China's socialist market economic system. It is argued that the supply of bicycles is elastic. Despite increased investment, labor, and fixed assets, profits will not grow. However the entertainment industry, as well as education, public welfare, urban utilities, noncommercialized housing, and telephones are less elastic. A large consumer population and a smaller supply elasticity result in high costs of installation, which are made higher by the state monopoly. It is argued that in China it is necessary to regulate certain necessities with less market elasticity in order to be consistent with optimum allocation of resources.

  20. cloncase: Estimation of sex frequency and effective population size by clonemate resampling in partially clonal organisms.

    PubMed

    Ali, Sajid; Soubeyrand, Samuel; Gladieux, Pierre; Giraud, Tatiana; Leconte, Marc; Gautier, Angélique; Mboup, Mamadou; Chen, Wanquan; de Vallavieille-Pope, Claude; Enjalbert, Jérôme

    2016-07-01

    Inferring reproductive and demographic parameters of populations is crucial to our understanding of species ecology and evolutionary potential but can be challenging, especially in partially clonal organisms. Here, we describe a new and accurate method, cloncase, for estimating both the rate of sexual vs. asexual reproduction and the effective population size, based on the frequency of clonemate resampling across generations. Simulations showed that our method provides reliable estimates of sex frequency and effective population size for a wide range of parameters. The cloncase method was applied to Puccinia striiformis f.sp. tritici, a fungal pathogen causing stripe/yellow rust, an important wheat disease. This fungus is highly clonal in Europe but has been suggested to recombine in Asia. Using two temporally spaced samples of P. striiformis f.sp. tritici in China, the estimated sex frequency was 75% (i.e. three-quarter of individuals being sexually derived during the yearly sexual cycle), indicating strong contribution of sexual reproduction to the life cycle of the pathogen in this area. The inferred effective population size of this partially clonal organism (Nc  = 998) was in good agreement with estimates obtained using methods based on temporal variations in allelic frequencies. The cloncase estimator presented herein is the first method allowing accurate inference of both sex frequency and effective population size from population data without knowledge of recombination or mutation rates. cloncase can be applied to population genetic data from any organism with cyclical parthenogenesis and should in particular be very useful for improving our understanding of pest and microbial population biology. PMID:26858112

  1. The influence of male parr body size and mate competition on fertilization success and effective population size in Atlantic salmon.

    PubMed

    Jones, M W; Hutchings, J A

    2001-06-01

    Alternative mating strategies in male Atlantic salmon, Salmo salar, are characterized by variability in body size and mate competition. Controlling breeding numbers of larger, older anadromous males, we examined whether body size of mature male parr influenced fertilization success and whether such an association was affected by mate competition among parr. Variation at three to four hypervariable microsatellite loci was used to determine individual paternity of 53-60 offspring from two or three nests from each experimental treatment. Although individual and total parr reproductive success differed significantly among nests within treatments, there was no relationship between parr size and individual reproductive success at any level of competition when anadromous males were involved. However, in a single treatment having no anadromous male, the influence of body size on parr fertilization success was highly significant. Combining data from all treatments, parr body size was an important predictor of the probability of an individual being involved in spawning. We found a negative relationship between total parr reproductive success and intensity of anadromous male competition. To our knowledge, the present study is the first to estimate the effective number of males from individual fertilization success in fish. Our estimates of Ne should not be taken as absolute and may have a downward bias because we did not sample all nests and we used a proxy for lifetime reproductive success. They do, however, illustrate how mature male parr can greatly increase the effective number of males when the latter is estimated from anadromous individuals alone. Although reproductive success by mature male parr increases the effective number of males, this increase seems likely to be most pronounced in natural populations when the number of anadromous males is low.

  2. The influence of simulated exploitation on Patella vulgata populations: protandric sex change is size-dependent.

    PubMed

    Borges, Carla D G; Hawkins, Stephen J; Crowe, Tasman P; Doncaster, C Patrick

    2016-01-01

    Grazing mollusks are used as a food resource worldwide, and limpets are harvested commercially for both local consumption and export in several countries. This study describes a field experiment to assess the effects of simulated human exploitation of limpets Patella vulgata on their population ecology in terms of protandry (age-related sex change from male to female), growth, recruitment, migration, and density regulation. Limpet populations at two locations in southwest England were artificially exploited by systematic removal of the largest individuals for 18 months in plots assigned to three treatments at each site: no (control), low, and high exploitation. The shell size at sex change (L 50: the size at which there is a 50:50 sex ratio) decreased in response to the exploitation treatments, as did the mean shell size of sexual stages. Size-dependent sex change was indicated by L 50 occurring at smaller sizes in treatments than controls, suggesting an earlier switch to females. Mean shell size of P. vulgata neuters changed little under different levels of exploitation, while males and females both decreased markedly in size with exploitation. No differences were detected in the relative abundances of sexual stages, indicating some compensation for the removal of the bigger individuals via recruitment and sex change as no migratory patterns were detected between treatments. At the end of the experiment, 0-15 mm recruits were more abundant at one of the locations but no differences were detected between treatments. We conclude that sex change in P. vulgata can be induced at smaller sizes by reductions in density of the largest individuals reducing interage class competition. Knowledge of sex-change adaptation in exploited limpet populations should underpin strategies to counteract population decline and improve rocky shore conservation and resource management.

  3. The influence of simulated exploitation on Patella vulgata populations: protandric sex change is size-dependent.

    PubMed

    Borges, Carla D G; Hawkins, Stephen J; Crowe, Tasman P; Doncaster, C Patrick

    2016-01-01

    Grazing mollusks are used as a food resource worldwide, and limpets are harvested commercially for both local consumption and export in several countries. This study describes a field experiment to assess the effects of simulated human exploitation of limpets Patella vulgata on their population ecology in terms of protandry (age-related sex change from male to female), growth, recruitment, migration, and density regulation. Limpet populations at two locations in southwest England were artificially exploited by systematic removal of the largest individuals for 18 months in plots assigned to three treatments at each site: no (control), low, and high exploitation. The shell size at sex change (L 50: the size at which there is a 50:50 sex ratio) decreased in response to the exploitation treatments, as did the mean shell size of sexual stages. Size-dependent sex change was indicated by L 50 occurring at smaller sizes in treatments than controls, suggesting an earlier switch to females. Mean shell size of P. vulgata neuters changed little under different levels of exploitation, while males and females both decreased markedly in size with exploitation. No differences were detected in the relative abundances of sexual stages, indicating some compensation for the removal of the bigger individuals via recruitment and sex change as no migratory patterns were detected between treatments. At the end of the experiment, 0-15 mm recruits were more abundant at one of the locations but no differences were detected between treatments. We conclude that sex change in P. vulgata can be induced at smaller sizes by reductions in density of the largest individuals reducing interage class competition. Knowledge of sex-change adaptation in exploited limpet populations should underpin strategies to counteract population decline and improve rocky shore conservation and resource management. PMID:26843935

  4. Diminishing Returns of Population Size in the Rate of RNA Virus Adaptation

    PubMed Central

    Miralles, Rosario; Moya, Andrés; Elena, Santiago F.

    2000-01-01

    Whenever an asexual viral population evolves by adapting to new environmental conditions, beneficial mutations, the ultimate cause of adaptation, are randomly produced and then fixed in the population. The larger the population size and the higher the mutation rate, the more beneficial mutations can be produced per unit time. With the usually high mutation rate of RNA viruses and in a large enough population, several beneficial mutations could arise at the same time but in different genetic backgrounds, and if the virus is asexual, they will never be brought together through recombination. Thus, the best of these genotypes must outcompete each other on their way to fixation. This competition among beneficial mutations has the effect of slowing the overall rate of adaptation. This phenomenon is known as clonal interference. Clonal interference predicts a speed limit for adaptation as the population size increases. In the present report, by varying the size of evolving vesicular stomatitis virus populations, we found evidence clearly demonstrating this speed limit and thus indicating that clonal interference might be an important factor modulating the rate of adaptation to an in vitro cell system. Several evolutionary and epidemiological implications of the clonal interference model applied to RNA viruses are discussed. PMID:10729131

  5. Survival and population size estimation in raptor studies: A comparison of two methods

    USGS Publications Warehouse

    Gould, William R.; Fuller, Mark R.

    1995-01-01

    ABSTRACT.--The Jolly-Seber model is a capture-recapture model that can provide less-biased survival and population size estimates than those produced from simple counting procedures. Parameter estimation by simple counts and Jolly-Seber methods are based on certain assumptions that directly determine the validity of estimates. Evuluation of assumptions for parameter estimation is a focus of this paper and used as a basis for determining which methods are more likely to produce better estimates. An example of population size and survival estimation for a peregrine falcon(Falco peregrinus) population in western Greenland is used to compare the two methods.Based on results from the Greenland peregrine population, and an assessment of the underlying assumptions of simple counts and the Jolly-Seber model,we suggest that Jolly-Seber estimation of survival and population size is less biased than simple counts in studies with marked birds. We recommend the use of a Jolly-Seber analysis of data when capture-recapture techniques are employed in raptor population studies.

  6. The effect of life-history variation on the population size structure of a rocky intertidal snail ( Littorina sitkana)

    NASA Astrophysics Data System (ADS)

    Rochette, Rémy; Dunmall, Karen; Dill, Lawrence M.

    2003-03-01

    On wave-sheltered shores of the northeastern Pacific, the population size structure of Littorina sitkana varies with intertidal height, as larger snails are mostly found only in the upper intertidal. This pattern has been attributed to high predation rates by crabs (and perhaps fish) on large snails inhabiting low-intertidal areas; i.e., large snails are presumed to be rare there simply because predators kill them. In this study we investigate the hypothesis that predation contributes to the shore-level size gradient displayed by L. sitkana by selecting for (or inducing) earlier sexual maturation and reduced somatic growth in low-shore snails relative to high-shore individuals. In the first part of our study, we carried out laboratory dissections, field experiments (mark-release-recapture and caging), and field surveys on a wave-protected shore in Bamfield Inlet, Barkley Sound (British Columbia, Canada). The principal results were: (1) adult survivorship was greater at higher, than at lower, intertidal level, (2) snails displayed a preference for their shore level of origin, (3) immature adults from the high intertidal displayed greater rates of somatic growth relative to immature adults from the low intertidal, and (4) low-shore snails matured at a smaller size than high-shore individuals. In the second part of the study, a large-scale survey showed intra-specific variation in size at sexual maturity (point 4 above) to be relatively consistent over time (winter of 1999 and 2001 for snails from our main study site) and space (13 different sites in winter 2001), although the magnitude of these differences varied greatly from shore to shore. Our results indicate that L. sitkana individuals inhabiting upper and lower parts of their intertidal range allocate resources differently to somatic and gonadal growth, an intra-specific difference that is best interpreted as a response to spatial and size-dependent variation in predation pressure. Taken together, results of

  7. Size of spawning population, residence time, and territory shifts of individuals in the spawning aggregation of a riverine catostomid

    USGS Publications Warehouse

    Grabowski, T.B.; Isely, J.J.

    2008-01-01

    Little is known about the behavior of individual fish in a spawning aggregation, specifically how long an individual remains in an aggregation. We monitored Moxostoma robustum (Cope) (Robust Redhorse) in a Savannah River spawning aggregation during spring 2004 and 2005 to provide an estimate of the total number of adults and the number of males comprising the aggregation and to determine male residence time and movements within a spawning aggregation. Robust Redhorse were captured using prepostioned grid electrofishers, identified to sex, weighed, measured, and implanted with a passive integrated transponder. Spawning aggregation size was estimated using a multiple census mark-and-recapture procedure. The spawning aggregation seemed to consist of approximately the same number of individuals (82-85) and males (50-56) during both years of this study. Individual males were present for a mean of 3.6 ?? 0.24 days (?? SE) during the 12-day spawning period. The mean distance between successive recaptures of individual males was 15.9 ?? 1.29 m (?? SE). We conclude that males establish spawning territories on a daily basis and are present within the spawning aggregation for at least 3-4 days. The relatively short duration of the aggregation may be the result of an extremely small population of adults. However, the behavior of individuals has the potential to influence population estimates made while fish are aggregated for spawning.

  8. Asian elephants in China: estimating population size and evaluating habitat suitability.

    PubMed

    Zhang, Li; Dong, Lu; Lin, Liu; Feng, Limin; Yan, Fan; Wang, Lanxin; Guo, Xianming; Luo, Aidong

    2015-01-01

    We monitored the last remaining Asian elephant populations in China over the past decade. Using DNA tools and repeat genotyping, we estimated the population sizes from 654 dung samples collected from various areas. Combined with morphological individual identifications from over 6,300 elephant photographs taken in the wild, we estimated that the total Asian elephant population size in China is between 221 and 245. Population genetic structure and diversity were examined using a 556-bp fragment of mitochondrial DNA, and 24 unique haplotypes were detected from DNA analysis of 178 individuals. A phylogenetic analysis revealed two highly divergent clades of Asian elephants, α and β, present in Chinese populations. Four populations (Mengla, Shangyong, Mengyang, and Pu'Er) carried mtDNA from the α clade, and only one population (Nangunhe) carried mtDNA belonging to the β clade. Moreover, high genetic divergence was observed between the Nangunhe population and the other four populations; however, genetic diversity among the five populations was low, possibly due to limited gene flow because of habitat fragmentation. The expansion of rubber plantations, crop cultivation, and villages along rivers and roads had caused extensive degradation of natural forest in these areas. This had resulted in the loss and fragmentation of elephant habitats and had formed artificial barriers that inhibited elephant migration. Using Geographic Information System, Global Positioning System, and Remote Sensing technology, we found that the area occupied by rubber plantations, tea farms, and urban settlements had dramatically increased over the past 40 years, resulting in the loss and fragmentation of elephant habitats and forming artificial barriers that inhibit elephant migration. The restoration of ecological corridors to facilitate gene exchange among isolated elephant populations and the establishment of cross-boundary protected areas between China and Laos to secure their natural

  9. Asian Elephants in China: Estimating Population Size and Evaluating Habitat Suitability

    PubMed Central

    Zhang, Li; Dong, Lu; Lin, Liu; Feng, Limin; Yan, Fan; Wang, Lanxin; Guo, Xianming; Luo, Aidong

    2015-01-01

    We monitored the last remaining Asian elephant populations in China over the past decade. Using DNA tools and repeat genotyping, we estimated the population sizes from 654 dung samples collected from various areas. Combined with morphological individual identifications from over 6,300 elephant photographs taken in the wild, we estimated that the total Asian elephant population size in China is between 221 and 245. Population genetic structure and diversity were examined using a 556-bp fragment of mitochondrial DNA, and 24 unique haplotypes were detected from DNA analysis of 178 individuals. A phylogenetic analysis revealed two highly divergent clades of Asian elephants, α and β, present in Chinese populations. Four populations (Mengla, Shangyong, Mengyang, and Pu’Er) carried mtDNA from the α clade, and only one population (Nangunhe) carried mtDNA belonging to the β clade. Moreover, high genetic divergence was observed between the Nangunhe population and the other four populations; however, genetic diversity among the five populations was low, possibly due to limited gene flow because of habitat fragmentation. The expansion of rubber plantations, crop cultivation, and villages along rivers and roads had caused extensive degradation of natural forest in these areas. This had resulted in the loss and fragmentation of elephant habitats and had formed artificial barriers that inhibited elephant migration. Using Geographic Information System, Global Positioning System, and Remote Sensing technology, we found that the area occupied by rubber plantations, tea farms, and urban settlements had dramatically increased over the past 40 years, resulting in the loss and fragmentation of elephant habitats and forming artificial barriers that inhibit elephant migration. The restoration of ecological corridors to facilitate gene exchange among isolated elephant populations and the establishment of cross-boundary protected areas between China and Laos to secure their natural

  10. Conspecific plant-soil feedback scales with population size in Lobelia siphilitica (Lobeliaceae).

    PubMed

    Hovatter, Stephanie; Blackwood, Christopher B; Case, Andrea L

    2013-12-01

    Plant-soil interactions directly affect plant success in terms of establishment, survival, growth and reproduction. Negative plant-soil feedback on such traits may therefore reduce the density and abundance of plants of a given species at a given site. Furthermore, if conspecific feedback varies among population sites, it could help explain geographic variation in plant population size. We tested for among-site variation in conspecific plant-soil feedback in a greenhouse experiment using seeds and soils from 8 natural populations of Lobelia siphilitica hosting 30-330 plants. The first cohort of seeds was grown on soil collected from each native site, while the second cohort was grown on the soil conditioned by the first. Our goal was to distinguish site-specific effects mediated by biotic and/or abiotic soil properties from those inherent in seed sources. Cohort 1 plants grown from seeds produced in small populations performed better in terms of germination, growth, and survival compared to plants produced in large populations. Plant performance decreased substantially between cohorts, indicating strong negative feedback. Most importantly, the strength of negative feedback scaled linearly (i.e., was less negative) with increasing size of the native plant population, particularly for germination and survival, and was better explained by soil- rather than seed-source effects. Even with a small number of sites, our results suggest that the potential for negative plant-soil feedback varies among populations of L. siphilitica, and that small populations were more susceptible to negative feedback. Conspecific plant-soil feedback may contribute to plant population size variation within a species' native range.

  11. Interactions between size-structured predator and prey populations: Experimental test and model comparison

    SciTech Connect

    Rice, J.A.; Crowder, L.B. ); Rose, K.A. )

    1993-05-01

    Because predation mortality is often size-dependent, the survival and size structure of prey populations may vary substantially depending on the size structure of the predator assemblage. We tested this hypothesis in a replicated pond experiment in which a bimodal size distribution of young-of-year spot Leiostomus xanthurus was exposed to two sizes of southern flounder Paralichthys lethostigma, each predator size-group present alone or together, at densities providing equal predation pressure. After 3 weeks, we examined cohort survival and size distributions of remaining spot. In the non-predator controls, spot size-frequency distributions were essentially unchanged, and survival of the large- and small-spot cohorts was similar. However, the size distribution of survivors, and the relative survival of large- and small-spot cohorts, differed markedly with the size structure of the predator assemblage. In the presence of small southern flounders, the large-spot cohort survived 4 times better than the small-spot cohort. In the large-flounder-only treatment, small spot survived 2.4 times better than large spot. When both large and small southern flounders were present, large spot had a net advantage, exceeding small spot survival by 2.4 times. We developed an individual-based model of the flounder-spot size-dependent predation interaction based on data from independent laboratory observations on size-based prey profit-ability, and used it to simulate the results of our experimental treatments. Model predictions of spot survival and size distributions agreed well with the pond experimental results when encounter rates were assumed to scale with spot size and density and with southern flounder density. 37 refs., 5 figs., 2 tabs.

  12. The sexual identity of adult intestinal stem cells controls organ size and plasticity.

    PubMed

    Hudry, Bruno; Khadayate, Sanjay; Miguel-Aliaga, Irene

    2016-02-18

    Sex differences in physiology and disease susceptibility are commonly attributed to developmental and/or hormonal factors, but there is increasing realization that cell-intrinsic mechanisms play important and persistent roles. Here we use the Drosophila melanogaster intestine to investigate the nature and importance of cellular sex in an adult somatic organ in vivo. We find that the adult intestinal epithelium is a cellular mosaic of different sex differentiation pathways, and displays extensive sex differences in expression of genes with roles in growth and metabolism. Cell-specific reversals of the sexual identity of adult intestinal stem cells uncovers the key role this identity has in controlling organ size, reproductive plasticity and response to genetically induced tumours. Unlike previous examples of sexually dimorphic somatic stem cell activity, the sex differences in intestinal stem cell behaviour arise from intrinsic mechanisms that control cell cycle duration and involve a new doublesex- and fruitless-independent branch of the sex differentiation pathway downstream of transformer. Together, our findings indicate that the plasticity of an adult somatic organ is reversibly controlled by its sexual identity, imparted by a new mechanism that may be active in more tissues than previously recognized. PMID:26887495

  13. The sexual identity of adult intestinal stem cells controls organ size and plasticity

    PubMed Central

    Hudry, Bruno; Khadayate, Sanjay; Miguel-Aliaga, Irene

    2016-01-01

    SUMMARY Sex differences in physiology and disease susceptibility are commonly attributed to developmental and/or hormonal factors, but there is increasing realisation that cell-intrinsic mechanisms play important and persistent roles1,2. Here we use the Drosophila melanogaster intestine to investigate the nature and significance of cellular sex in an adult somatic organ in vivo. We find that the adult intestinal epithelium is a cellular mosaic of different sex differentiation pathways, and displays extensive sex differences in expression of genes with roles in growth and metabolism. Cell-specific reversals of the sexual identity of adult intestinal stem cells uncover its key roles in controlling organ size, its reproductive plasticity and its response to genetically induced tumours. Unlike previous examples of sexually dimorphic somatic stem cell activity, the sex differences in intestinal stem cell behaviour arise from intrinsic mechanisms, which control cell cycle duration and involve a new doublesex- and fruitless-independent branch of the sex differentiation pathway downstream of transformer. Together, our findings indicate that the plasticity of an adult somatic organ is reversibly controlled by its sexual identity, imparted by a new mechanism that may be active in more tissues than previously recognised. PMID:26887495

  14. Sequence diversity under the multispecies coalescent with Yule process and constant population size.

    PubMed

    Heled, Joseph

    2012-03-01

    The study of sequence diversity under phylogenetic models is now classic. Theoretical studies of diversity under the Kingman coalescent appeared shortly after the introduction of the coalescent. In this paper we revisit this topic under the multispecies coalescent, an extension of the single population model to multiple populations. We derive exact formulas for the sequence dissimilarity of two sequences drawn at random under a basic multispecies setup. The multispecies model uses three parameters--the species tree birth rate under the pure birth process (Yule), the species effective population size and the mutation rate. We also discuss the effects of relaxing some of the model assumptions.

  15. Quantifying the Variation in the Effective Population Size Within a Genome

    PubMed Central

    Gossmann, Toni I.; Woolfit, Megan; Eyre-Walker, Adam

    2011-01-01

    The effective population size (Ne) is one of the most fundamental parameters in population genetics. It is thought to vary across the genome as a consequence of differences in the rate of recombination and the density of selected sites due to the processes of genetic hitchhiking and background selection. Although it is known that there is intragenomic variation in the effective population size in some species, it is not known whether this is widespread or how much variation in the effective population size there is. Here, we test whether the effective population size varies across the genome, between protein-coding genes, in 10 eukaryotic species by considering whether there is significant variation in neutral diversity, taking into account differences in the mutation rate between loci by using the divergence between species. In most species we find significant evidence of variation. We investigate whether the variation in Ne is correlated to recombination rate and the density of selected sites in four species, for which these data are available. We find that Ne is positively correlated to recombination rate in one species, Drosophila melanogaster, and negatively correlated to a measure of the density of selected sites in two others, humans and Arabidopsis thaliana. However, much of the variation remains unexplained. We use a hierarchical Bayesian analysis to quantify the amount of variation in the effective population size and show that it is quite modest in all species—most genes have an Ne that is within a few fold of all other genes. Nonetheless we show that this modest variation in Ne is sufficient to cause significant differences in the efficiency of natural selection across the genome, by demonstrating that the ratio of the number of nonsynonymous to synonymous polymorphisms is significantly correlated to synonymous diversity and estimates of Ne, even taking into account the obvious nonindependence between these measures. PMID:21954163

  16. Adult hippocampal neurogenesis in natural populations of mammals.

    PubMed

    Amrein, Irmgard

    2015-05-01

    This review will discuss adult hippocampal neurogenesis in wild mammals of different taxa and outline similarities with and differences from laboratory animals. It begins with a review of evidence for hippocampal neurogenesis in various mammals, and shows the similar patterns of age-dependent decline in cell proliferation in wild and domesticated mammals. In contrast, the pool of immature neurons that originate from proliferative activity varies between species, implying a selective advantage for mammals that can make use of a large number of these functionally special neurons. Furthermore, rapid adaptation of hippocampal neurogenesis to experimental challenges appears to be a characteristic of laboratory rodents. Wild mammals show species-specific, rather stable hippocampal neurogenesis, which appears related to demands that characterize the niche exploited by a species rather than to acute events in the life of its members. Studies that investigate adult neurogenesis in wild mammals are not numerous, but the findings of neurogenesis under natural conditions can provide new insights, and thereby also address the question to which cognitive demands neurogenesis may respond during selection.

  17. Reduced productivity in adult yellowfever mosquito (Diptera: Culicidae) populations

    SciTech Connect

    Rodriguez, P.H.; Hamm, W.J.; Garcia, F.; Garcia, M.; Schirf, V.

    1989-04-01

    Male and female Aedes aegypti (L.) mosquitoes of the laboratory strain ROCK were irradiated with 130 mw of argon 514.5 nm laser microbeams for 0.04, 0.25, 0.4, and 0.5 s, respectively. Egg production, percentage hatch, and productivity (average number of adults surviving after 3 wk) were used to assess mutagenic effects. Mortality was high for males in all laser radiation groups and increased with time of exposure. Except for the group treated for 0.25 s, significant reductions in total F1 progeny also were demonstrated for all other experimentals when male parents were exposed to laser radiation. Females showed a high mortality when subjected to 0.4- and 0.5-s laser radiation. No F1 progeny were produced when parental females were exposed for 0.25, 0.4, and 0.5 s. Numbers of F1 progeny from females exposed to 0.04 s of laser radiation were significantly reduced. A comparison of weekly mean number of progeny showed that the important differences in productivity occurred during the first and second week, respectively, when either male or female adult parents were subjected to laser radiation.

  18. Methods used to estimate the size of the owned cat and dog population: a systematic review

    PubMed Central

    2013-01-01

    Background There are a number of different methods that can be used when estimating the size of the owned cat and dog population in a region, leading to varying population estimates. The aim of this study was to conduct a systematic review to evaluate the methods that have been used for estimating the sizes of owned cat and dog populations and to assess the biases associated with those methods. A comprehensive, systematic search of seven electronic bibliographic databases and the Google search engine was carried out using a range of different search terms for cats, dogs and population. The inclusion criteria were that the studies had involved owned or pet domestic dogs and/or cats, provided an estimate of the size of the owned dog or cat population, collected raw data on dog and cat ownership, and analysed primary data. Data relating to study methodology were extracted and assessed for biases. Results Seven papers were included in the final analysis. Collection methods used to select participants in the included studies were: mailed surveys using a commercial list of contacts, door to door surveys, random digit dialled telephone surveys, and randomised telephone surveys using a commercial list of numbers. Analytical and statistical methods used to estimate the pet population size were: mean number of dogs/cats per household multiplied by the number of households in an area, human density multiplied by number of dogs per human, and calculations using predictors of pet ownership. Conclusion The main biases of the studies included selection bias, non-response bias, measurement bias and biases associated with length of sampling time. Careful design and planning of studies is a necessity before executing a study to estimate pet populations. PMID:23777563

  19. Population structure and effective/census population size ratio in threatened three-spined stickleback populations from an isolated river basin in northwest Spain.

    PubMed

    Pérez-Figueroa, A; Fernández, C; Amaro, R; Hermida, M; San Miguel, E

    2015-08-01

    Variability at 20 microsatellite loci was examined to assess the population genetic structure, gene flow, and effective population size (N(e)) in three populations of three-spined stickleback (Gasterosteus aculeatus) from the upper basin of the Miño River in Galicia, NW Spain, where this species is threatened. The three populations showed similar levels of genetic diversity. There is a significant genetic differentiation between the three populations, but also significant gene flow. N(e) estimates based on linkage disequilibrium yielded values of 355 for the Miño River population and 241 and 311 for the Rato and Guisande Rivers, respectively, although we expect that these are overestimates. N(e) estimates based on temporal methods, considering gene flow or not, for the tributaries yielded values of 30-56 and 47-56 for the Rato and Guisande Rivers, respectively. Estimated census size (N(c)) for the Rato River was 880 individuals. This yielded a N(e)/N(c) estimate of 3-6 % for temporal estimation of N(e), which is within the empirical range observed in freshwater fishes. We suggest that the three populations analyzed have a sufficient level of genetic diversity with some genetic structure. Additionally, the absence of physical barriers suggests that conservation efforts and monitoring should focus in the whole basin as a unit.

  20. Health effects of ambient levels of respirable particulate matter (PM) on healthy, young-adult population

    NASA Astrophysics Data System (ADS)

    Shaughnessy, William J.; Venigalla, Mohan M.; Trump, David

    2015-12-01

    There is an absence of studies that define the relationship between ambient particulate matter (PM) levels and adverse health outcomes among the young and healthy adult sub-group. In this research, the relationship between exposures to ambient levels of PM in the 10 micron (PM10) and 2.5 micron (PM2.5) size fractions and health outcomes in members of the healthy, young-adult subgroup who are 18-39 years of age was examined. Active duty military personnel populations at three strategically selected military bases in the United States were used as a surrogate to the control group. Health outcome data, which consists of the number of diagnoses for each of nine International Classification of Diseases, 9th Revision (ICD-9) categories related to respiratory illness, were derived from outpatient visits at each of the three military bases. Data on ambient concentrations of particulate matter, specifically PM10 and PM2.5, were obtained for these sites. The health outcome data were correlated and regressed with the PM10 and PM2.5 data, and other air quality and weather-related data on a daily and weekly basis for the period 1998 to 2004. Results indicate that at Fort Bliss, which is a US Environmental Protection Agency designated non-attainment area for PM10, a statistically significant association exists between the weekly-averaged number of adverse health effects in the young and healthy adult population and the corresponding weekly-average ambient PM10 concentration. A least squares regression analysis was performed on the Fort Bliss data sets indicated that the health outcome data is related to several environmental parameters in addition to PM10. Overall, the analysis estimates a .6% increase in the weekly rate of emergency room visits for upper respiratory infections for every 10 μg/m3 increase in the weekly-averaged PM10 concentration above the mean. The findings support the development of policy and guidance opportunities that can be developed to mitigate exposures

  1. METER-SIZED MOONLET POPULATION IN SATURN'S C RING AND CASSINI DIVISION

    SciTech Connect

    Baillie, Kevin; Colwell, Joshua E.; Esposito, Larry W.; Lewis, Mark C.

    2013-06-01

    Stellar occultations observed by the Cassini Ultraviolet Imaging Spectrograph reveal the presence of transparent holes a few meters to a few tens of meters in radial extent in otherwise optically thick regions of the C ring and the Cassini Division. We attribute the holes to gravitational disturbances generated by a population of {approx}10 m boulders in the rings that is intermediate in size between the background ring particle size distribution and the previously observed {approx}100 m propeller moonlets in the A ring. The size distribution of these boulders is described by a shallower power-law than the one that describes the ring particle size distribution. The number and size distribution of these boulders could be explained by limited accretion processes deep within Saturn's Roche zone.

  2. Status and trends of adult Lost River (Deltistes luxatus) and shortnose (Chasmistes brevirostris) sucker populations in Upper Klamath Lake, Oregon, 2014

    USGS Publications Warehouse

    Hewitt, David A.; Janney, Eric C.; Hayes, Brian S.; Harris, Alta C.

    2015-10-02

    Despite relatively high survival in most years, we conclude that both species have experienced substantial decreases in the abundance of spawning adults because losses from mortality have not been balanced by recruitment of new individuals. Although capture-recapture data indicate substantial recruitment of new individuals into the spawning populations for SNS and river spawning LRS in some years, size data do not corroborate these estimates. As a result, the status of the endangered sucker populations in Upper Klamath Lake remains worrisome, especially for shortnose suckers. Our monitoring program provides a robust platform for estimating vital population parameters, evaluating the status of the populations, and assessing the effectiveness of conservation and recovery efforts.

  3. Does cannibalism of larvae by adults affect settlement and connectivity of mussel populations?

    NASA Astrophysics Data System (ADS)

    Porri, Francesca; Jordaan, Tembisa; McQuaid, Christopher D.

    2008-09-01

    Intertidal population dynamics are driven by a complex series of processes, including larval supply and the possibility of larval predation by benthic animals such as filter-feeders. We hypothesised that cannibalism by adults could play a major role in the population connectivity of mussel populations by removing larvae as they attempt to settle in the adult habitat. Specifically, we tested hypotheses that consumption of mussel larvae by adults removes a significant proportion of potential settlers and is influenced by both settlement intensity and tidal state (flooding or ebbing). Predation of mussel larvae by adult mussels was investigated on incoming and ebbing tides during four spring tides by analysing the gut contents of adult Perna perna and Mytilus galloprovincialis collected from the low intertidal mussel zone between October 2005 and January 2006. Consumption rates were then compared with estimates of successful settler densities on natural beds. The results showed that mortality of competent mussel larvae through adult ingestion removes up to 77% a of potential settlers. Rates of larval consumption were highest during months of intense settlement, suggesting that mussels feed opportunistically, filtering a relatively fixed volume of water and removing particles, including larvae, in proportion to their densities in the water. Rates of larviphagy were also higher during receding than incoming tides. We suggest that this is due to changes in larval density or, more probably, in adult filtration efficiency that are related to the state of the tide. Despite significant effects of both tidal state and settlement intensity on rates of larval ingestion, neither had a significant effect on the proportion of potential settlers removed. During settlement more than half of all potential settlers are lost through cannibalism, with potentially serious consequences for population maintenance. The results highlight the paradoxical nature of the evolution of settlement

  4. Short-Term Genetic Changes: Evaluating Effective Population Size Estimates in a Comprehensively Described Brown Trout (Salmo trutta) Population

    PubMed Central

    Serbezov, Dimitar; Jorde, Per Erik; Bernatchez, Louis; Olsen, Esben Moland; Vøllestad, L. Asbjørn

    2012-01-01

    The effective population size (Ne) is notoriously difficult to accurately estimate in wild populations as it is influenced by a number of parameters that are difficult to delineate in natural systems. The different methods that are used to estimate Ne are affected variously by different processes at the population level, such as the life-history characteristics of the organism, gene flow, and population substructure, as well as by the frequency patterns of genetic markers used and the sampling design. Here, we compare Ne estimates obtained by different genetic methods and from demographic data and elucidate how the estimates are affected by various factors in an exhaustively sampled and comprehensively described natural brown trout (Salmo trutta) system. In general, the methods yielded rather congruent estimates, and we ascribe that to the adequate genotyping and exhaustive sampling. Effects of violating the assumptions of the different methods were nevertheless apparent. In accordance with theoretical studies, skewed allele frequencies would underestimate temporal allele frequency changes and thereby upwardly bias Ne if not accounted for. Overlapping generations and iteroparity would also upwardly bias Ne when applied to temporal samples taken over short time spans. Gene flow from a genetically not very dissimilar source population decreases temporal allele frequency changes and thereby acts to increase estimates of Ne. Our study reiterates the importance of adequate sampling, quantification of life-history parameters and gene flow, and incorporating these data into the Ne estimation. PMID:22466040

  5. Reduction of Salmonella Enteritidis Population Sizes on Almond Kernels with Infrared Heat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Catalytic infrared (IR) heating was investigated to determine its effect on Salmonella enterica serovar Enteritidis population sizes on raw almond kernels. Using a double-sided catalytic infrared heating system, a radiation intensity of 5458 W/m2 caused a fast temperature increase at the kernel surf...

  6. The influence of persistent individual differences and age at maturity on effective population size

    PubMed Central

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

    2011-01-01

    Ratios of effective populations size, Ne, to census population size, N, are used as a measure of genetic drift in populations. Several life-history parameters have been shown to affect these ratios, including mating system and age at sexual maturation. Using a stochastic matrix model, we examine how different levels of persistent individual differences in mating success among males may affect Ne/N, and how this relates to generation time. Individual differences of this type are shown to cause a lower Ne/N ratio than would be expected when mating is independent among seasons. Examining the way in which age at maturity affects Ne/N, we find that both the direction and magnitude of the effect depends on the survival rate of juveniles in the population. In particular, when maturation is delayed, lowered juvenile survival causes higher levels of genetic drift. In addition, predicted shifts in Ne/N with changing age at maturity are shown to be dependent on which of the commonly used definitions of census population size, N, is employed. Our results demonstrate that patterns of mating success, as well as juvenile survival probabilities, have substantial effects on rates of genetic drift. PMID:21436183

  7. Distribution of a Population of Rhizobium leguminosarum bv. trifolii among Different Size Classes of Soil Aggregates.

    PubMed

    Mendes, I C; Bottomley, P J

    1998-03-01

    A combination of the plant infection-soil dilution technique (most-probable-number [MPN] technique) and immunofluorescence direct count (IFDC) microscopy was used to examine the effects of three winter cover crop treatments on the distribution of a soil population of Rhizobium leguminosarum bv. trifolii across different size classes of soil aggregates (<0.25, 0.25 to 0.5, 0.5 to 1.0, 1.0 to 2.0, and 2.0 to 5.0 mm). The aggregates were prepared from a Willamette silt loam soil immediately after harvest of broccoli (September 1995) and before planting and after harvest of sweet corn (June and September 1996, respectively). The summer crops were grown in soil that had been either fallowed or planted with a cover crop of red clover (legume) or triticale (cereal) from September to April. The Rhizobium soil population was heterogeneously distributed across the different size classes of soil aggregates, and the distribution was influenced by cover crop treatment and sampling time. On both September samplings, the smallest size class of aggregates (<0.25 mm) recovered from the red clover plots carried between 30 and 70% of the total nodulating R. leguminosarum population, as estimated by the MPN procedure, while the same aggregate size class from the June sampling carried only approximately 6% of the population. In June, IDFC microscopy revealed that the 1.0- to 2.0-mm size class of aggregates from the red clover treatment carried a significantly greater population density of the successful nodule-occupying serotype, AR18, than did the aggregate size classes of <0.5 mm, and 2 to 5 mm. In September, however, the population profile of AR18 had shifted such that the density was significantly greater in the 0.25- to 0.5-mm size class than in aggregates of <0.25 mm and >1.0 mm. The populations of two other Rhizobium serotypes (AR6 and AS36) followed the same trends of distribution in the June and September samplings. These data indicate the existence of structural microsites

  8. Multiple aspects of plasticity in clutch size vary among populations of a globally distributed songbird.

    PubMed

    Westneat, David F; Bókony, Veronika; Burke, Terry; Chastel, Olivier; Jensen, Henrik; Kvalnes, Thomas; Lendvai, Ádám Z; Liker, András; Mock, Douglas; Schroeder, Julia; Schwagmeyer, P L; Sorci, Gabriele; Stewart, Ian R K

    2014-07-01

    Plasticity in life-history characteristics can influence many ecological and evolutionary phenomena, including how invading organisms cope with novel conditions in new locations or how environmental change affects organisms in native locations. Variation in reaction norm attributes is a critical element to understanding plasticity in life history, yet we know relatively little about the ways in which reaction norms vary within and among populations. We amassed data on clutch size from marked females in eight populations of house sparrows (Passer domesticus) from North America and Europe. We exploited repeated measures of clutch size to assess both the extent of within-individual phenotypic plasticity and among-individual variation and to test alternative hypotheses about the underlying causes of reaction norm shape, particularly the decline in clutch size with date. Across all populations, females of this multibrooded species altered their clutch size with respect to date, attempt order, and the interaction of date and order, producing a reaction norm in multidimensional environmental space. The reaction norm fits that predicted by a model in which optimal clutch size is driven by a decline with date hatched in the ability of offspring to recruit. Our results do not fit those predicted for other proposed causes of a seasonal decline in clutch size. We also found significant differences between populations in response to date and the date by attempt order interaction. We tested the prediction that the relationship with date should be increasingly negative as breeding season becomes shorter but found steeper declines in clutch size with date in populations with longer seasons, contrary to the prediction. Populations also differed in the level of among-individual variation in reaction norm intercept, but we found no evidence of among-individual variation in reaction norm slope. We show that complex reaction norms in life-history characters exhibit within- and among-population

  9. Caregiver Abuse of Chicago Chinese Older Adults in a Community-Dwelling Population

    PubMed Central

    Dong, Xin Qi; Li, Ge

    2016-01-01

    Objectives This study aimed to examine the prevalence and correlates of elder abuse reported by adult children among U.S Chinese populations. Method A community-based participatory research approach was implemented. A total of 548 Chinese adult children aged 21 years and over participated in this study. Elder abuse reported by adult children was assessed using Caregiver Abuse Screen (CASE). Results This study found a prevalence of 59.8%for elder abuse among 548 adult children. Younger age (r = −0.10, p < .05), higher level of education (r = 0.20, p < .001), higher income (r = 0.14, p < .01), more years in the U.S. (r = 0.12, p < .05), not born in Mainland China (r = −0.13, p < .01), and English-speaking (r = 0.16, p < .001) were positively correlated with elder abuse reported by adult children. Discussion Elder abuse by adult children is prevalent among U.S. Chinese populations. It is necessary for researchers, health care providers and policy makers to put more attention on elder abuse by adult children. Longitudinal research is needed to explore the risk factors associated with elder abuse by adult children. Health care providers should improve detection of elder abuse and support at-risk caregivers. Policy makers may consider cultural sensitive approaches to address elder abuse. PMID:27606358

  10. The Role of Body Size in Mate Selection among African American Young Adults

    PubMed Central

    Simons, Leslie G.; Simons, Ronald L.

    2016-01-01

    A profusion of studies have demonstrated that body size is a major factor in mate selection for both men and women. The particular role played by weight, however, has been subject to some debate, particularly with respect to the types of body sizes deemed most attractive, and scholars have questioned the degree to which body size preferences are constant across groups. In this paper, we drew from two perspectives on this issue, Sexual Strategies Theory and what we termed the cultural variability perspective, and used survey data to examine how body size was associated with both casual dating and serious romantic relationships. We used a United States sample of 386 African American adolescents and young adults between ages 16 and 21, living in the Midwest and Southeast, and who were enrolled in either high school or college. Results showed that overweight women were more likely to report casually dating than women in the thinnest weight category. Body size was not related to dating status among men. Among women, the results suggest stronger support for the cultural variability argument than for Sexual Strategies Theory. Potential explanations for these findings are discussed. PMID:26973377

  11. Fourth-Order Method for Numerical Integration of Age- and Size-Structured Population Models

    SciTech Connect

    Iannelli, M; Kostova, T; Milner, F A

    2008-01-08

    In many applications of age- and size-structured population models, there is an interest in obtaining good approximations of total population numbers rather than of their densities. Therefore, it is reasonable in such cases to solve numerically not the PDE model equations themselves, but rather their integral equivalents. For this purpose quadrature formulae are used in place of the integrals. Because quadratures can be designed with any order of accuracy, one can obtain numerical approximations of the solutions with very fast convergence. In this article, we present a general framework and a specific example of a fourth-order method based on composite Newton-Cotes quadratures for a size-structured population model.

  12. Prey size and scramble vs. contest competition in a social spider: implications for population dynamics.

    PubMed

    Sharpe, Ruth V; Avilés, Leticia

    2016-09-01

    There are many benefits of group living, but also substantial costs, one of which is competition for resources. How scarce food resources are distributed among different members of a population or social group - whether via scramble or contest competition - can influence not only the variance in individual fitness, but also the stability and therefore survival of the group or population. Attributes of the food resources themselves, such as their size, may influence the type of intraspecific competition that occurs and therefore the intrinsic stability of a group or population. By experimentally manipulating the size of prey fed to artificial colonies of the social spider Anelosimus eximius, we investigated whether prey size could alter the degree of scramble vs. contest competition that takes place and, thus, potentially influence colony population dynamics. We found that large prey were shared more evenly than small prey and that individuals in poor condition were more likely to feed when prey were large than when prey were small. Additionally, we show that individuals participating in prey capture are also more likely to feed on the captured prey. We developed a simple mathematical model to explore the prey sizes that would be energetically worth defending, i.e. prey that are 'economically defendable'. The model shows that neither very small prey, nor prey above a certain size is worth monopolizing, with only intermediate size prey being 'economically defendable'. We therefore suggest the small and large prey in our experiment corresponds to our model's intermediate and large prey categories, respectively. As the size of prey captured by social spider colonies increases with colony size, our findings suggest that scramble competition may predominate in large colonies. Scramble competition, combined with the fact that prey biomass per capita declines as colonies grow beyond a certain size, would then explain why extremely large colonies of this social spider may

  13. Prey size and scramble vs. contest competition in a social spider: implications for population dynamics.

    PubMed

    Sharpe, Ruth V; Avilés, Leticia

    2016-09-01

    There are many benefits of group living, but also substantial costs, one of which is competition for resources. How scarce food resources are distributed among different members of a population or social group - whether via scramble or contest competition - can influence not only the variance in individual fitness, but also the stability and therefore survival of the group or population. Attributes of the food resources themselves, such as their size, may influence the type of intraspecific competition that occurs and therefore the intrinsic stability of a group or population. By experimentally manipulating the size of prey fed to artificial colonies of the social spider Anelosimus eximius, we investigated whether prey size could alter the degree of scramble vs. contest competition that takes place and, thus, potentially influence colony population dynamics. We found that large prey were shared more evenly than small prey and that individuals in poor condition were more likely to feed when prey were large than when prey were small. Additionally, we show that individuals participating in prey capture are also more likely to feed on the captured prey. We developed a simple mathematical model to explore the prey sizes that would be energetically worth defending, i.e. prey that are 'economically defendable'. The model shows that neither very small prey, nor prey above a certain size is worth monopolizing, with only intermediate size prey being 'economically defendable'. We therefore suggest the small and large prey in our experiment corresponds to our model's intermediate and large prey categories, respectively. As the size of prey captured by social spider colonies increases with colony size, our findings suggest that scramble competition may predominate in large colonies. Scramble competition, combined with the fact that prey biomass per capita declines as colonies grow beyond a certain size, would then explain why extremely large colonies of this social spider may

  14. Stroop-like interference in the real animal size test and the pictorial animal size test in 5- to 12-year-old children and young adults.

    PubMed

    Ikeda, Yoshifumi; Okuzumi, Hideyuki; Kokubun, Mitsuru

    2014-01-01

    This study examined prepotent response inhibition among 653 5- to 12-year-old children and young adults divided into five age groups: forty-six 5- to 6-year-olds, one hundred fifty-eight 7- to 8-year-olds, one hundred ninety-six 9- to 10-year-olds, one hundred eighty-three 11- to 12-year-olds, and 70 young adults (19- to 22-year-olds). Two paper-and-pencil versions of Stroop-like tasks were administered: the Real Animal Size Test and the Pictorial Animal Size Test. In these tests, participants are presented with pictures of animals (large animals such as an elephant, a giraffe, and a whale vs. small animals such as a frog, a bird, and a squirrel) printed as either big or small images that are mismatched with the animal's real size. Participants are required to decide the size of the animals (big vs. small) based on either the size in real life or the size of the picture. The results indicated the following: (a) The Pictorial Animal Size Test elicited robust interference, whereas the Real Animal Size Test elicited no interference; (b) prepotent response inhibition develops markedly in childhood and between children and young adults; and (c) error correction increased rapidly after age 8. The mechanism of interference and the influence of metacognition on prepotent response inhibition are discussed. PMID:24716870

  15. Population size and trend of Yellow-billed Loons in northern Alaska

    USGS Publications Warehouse

    Earnst, Susan L.; Stehn, R.A.; Platte, Robert; Larned, W.W.; Mallek, E.J.

    2005-01-01

    The Yellow-billed Loon (Gavia adamsii) is of conservation concern due to its restricted range, small population size, specific habitat requirements, and perceived threats to its breeding and wintering habitat. Within the U.S., this species breeds almost entirely within the National Petroleum Reserve-Alaska, nearly all of which is open, or proposed to be opened, for oil development. Rigorous estimates of Yellow-billed Loon population size and trend are lacking but essential for informed conservation. We used two annual aerial waterfowl surveys, conducted 1986a??2003 and 1992a??2003, to estimate population size and trend on northern Alaskan breeding grounds. In estimating population trend, we used mixed-effects regression models to reduce bias and sampling error associated with improvement in observer skill and annual effects of spring phenology. The estimated population trend on Alaskan breeding grounds since 1986 was near 0 with an estimated annual change of a??0.9% (95% CI of a??3.6% to +1.8%). The estimated population size, averaged over the past 12 years and adjusted by a correction factor based on an intensive, lake-circling, aerial survey method, was 2221 individuals (95% CI of 1206a??3235) in early June and 3369 individuals (95% CI of 1910a??4828) in late June. Based on estimates from other studies of the proportion of loons nesting in a given year, it is likely that <1000 nesting pairs inhabit northern Alaska in most years. The highest concentration of Yellow-billed Loons occurred between the Meade and Ikpikpuk Rivers; and across all of northern Alaska, 53% of recorded sightings occurred within 12% of the area.

  16. Population Size and Decadal Trends of Three Penguin Species Nesting at Signy Island, South Orkney Islands

    PubMed Central

    Dunn, Michael J.; Jackson, Jennifer A.; Adlard, Stacey; Lynnes, Amanda S.; Briggs, Dirk R.; Fox, Derren; Waluda, Claire M.

    2016-01-01

    We report long-term changes in population size of three species of sympatrically breeding pygoscelid penguins: Adélie (Pygoscelis adeliae), chinstrap (Pygoscelis antarctica) and gentoo (Pygoscelis papua ellsworthii) over a 38 year period at Signy Island, South Orkney Islands, based on annual counts from selected colonies and decadal all-island systematic counts of occupied nests. Comparing total numbers of breeding pairs over the whole island from 1978/79 to 2015/16 revealed varying fortunes: gentoo penguin pairs increased by 255%, (3.5% per annum), chinstrap penguins declined by 68% (-3.6% per annum) and Adélie penguins declined by 42% (-1.5% per annum). The chinstrap population has declined steadily over the last four decades. In contrast, Adélie and gentoo penguins have experienced phases of population increase and decline. Annual surveys of selected chinstrap and Adélie colonies produced similar trends from those revealed by island-wide surveys, allowing total island population trends to be inferred relatively well. However, while the annual colony counts of chinstrap and Adélie penguins showed a trend consistent in direction with the results from all-island surveys, the magnitude of estimated population change was markedly different between colony wide and all island counts. Annual population patterns suggest that pair numbers in the study areas partly reflect immigration and emigration of nesting birds between different parts of the island. Breeding success for all three species remained broadly stable over time in the annually monitored colonies. Breeding success rates in gentoo and chinstrap penguins were strongly correlated, despite the differing trends in population size. This study shows the importance of effective, standardised monitoring to accurately determine long-term population trajectories. Our results indicate significant declines in the Adélie and chinstrap penguin populations at Signy Island over the last five decades, and a gradual

  17. Use of the superpopulation approach to estimate breeding population size: An example in asynchronously breeding birds

    USGS Publications Warehouse

    Williams, K.A.; Frederick, P.C.; Nichols, J.D.

    2011-01-01

    Many populations of animals are fluid in both space and time, making estimation of numbers difficult. Much attention has been devoted to estimation of bias in detection of animals that are present at the time of survey. However, an equally important problem is estimation of population size when all animals are not present on all survey occasions. Here, we showcase use of the superpopulation approach to capture-recapture modeling for estimating populations where group membership is asynchronous, and where considerable overlap in group membership among sampling occasions may occur. We estimate total population size of long-legged wading bird (Great Egret and White Ibis) breeding colonies from aerial observations of individually identifiable nests at various times in the nesting season. Initiation and termination of nests were analogous to entry and departure from a population. Estimates using the superpopulation approach were 47-382% larger than peak aerial counts of the same colonies. Our results indicate that the use of the superpopulation approach to model nesting asynchrony provides a considerably less biased and more efficient estimate of nesting activity than traditional methods. We suggest that this approach may also be used to derive population estimates in a variety of situations where group membership is fluid. ?? 2011 by the Ecological Society of America.

  18. Dispersal, niche breadth and population extinction: colonization ratios predict range size in North American dragonflies.

    PubMed

    McCauley, Shannon J; Davis, Christopher J; Werner, Earl E; Robeson, Michael S

    2014-07-01

    Species' range sizes are shaped by fundamental differences in species' ecological and evolutionary characteristics, and understanding the mechanisms determining range size can shed light on the factors responsible for generating and structuring biological diversity. Moreover, because geographic range size is associated with a species' risk of extinction and their ability to respond to global changes in climate and land use, understanding these mechanisms has important conservation implications. Despite the hypotheses that dispersal behaviour is a strong determinant of species range areas, few data are available to directly compare the relationship between dispersal behaviour and range size. Here, we overcome this limitation by combining data from a multispecies dispersal experiment with additional species-level trait data that are commonly hypothesized to affect range size (e.g. niche breadth, local abundance and body size.). This enables us to examine the relationship between these species-level traits and range size across North America for fifteen dragonfly species. Ten models based on a priori predictions about the relationship between species traits and range size were evaluated and two models were identified as good predictors of species range size. These models indicated that only two species' level traits, dispersal behaviour and niche breadth were strongly related to range size. The evidence from these two models indicated that dragonfly species that disperse more often and further had larger North American ranges. Extinction and colonization dynamics are expected to be a key linkage between dispersal behaviour and range size in dragonflies. To evaluate how extinction and colonization dynamics among dragonflies were related to range size we used an independent data set of extinction and colonization rates for eleven dragonfly species and assessed the relationship between these populations rates and North American range areas for these species. We found a

  19. Consequences of the size structure of fish populations for their effects on a generalist avian predator.

    PubMed

    Kloskowski, Janusz

    2011-06-01

    Size-structured interspecific interactions can shift between predation and competition, depending on ontogenetic changes in size relationships. I examined the effects of common carp (Cyprinus carpio), an omnivorous fish, on the reproductive success of the red-necked grebe (Podiceps grisegena), an avian gape-limited predator, along a fish size gradient created by stocking distinct age-cohorts in seminatural ponds. Young-of-the-year (0+) carp were an essential food source for young grebes. Only adult birds were able to consume 1-year-old (1+) fish, while 2-year-old (2+) fish attained a size refuge from grebes. Amphibian larvae were the principal alternative prey to fish, followed by macroinvertebrates, but the abundance of both dramatically decreased along the carp size gradient. Fledging success was 2.8 times greater in ponds with 0+ versus 1+ carp; in ponds with 1+ carp, chicks received on average 2.6-3 times less prey biomass from their parents, and over 1/3 of broods suffered total failure. Breeding birds avoided settling on 2+ ponds. These results show that changes in prey fish size structure can account for shifts from positive trophic effects on the avian predator to a negative impact on the predator's alternative resources. However, competition did not fully explain the decrease in grebe food resources in the presence of large fish, as carp and grebes overlapped little in diet. In experimental cages, 1+ carp totally eliminated young larvae of amphibians palatable to fish. In field conditions, breeding adults of palatable taxa avoided ponds with 1+ and older carp. Non-trophic interactions such as habitat selection by amphibians or macroinvertebrates to avoid large fish may provide an indirect mechanism strengthening the adverse bottom-up effects of fish on birds.

  20. Evaluating methods for estimating local effective population size with and without migration.

    PubMed

    Gilbert, Kimberly J; Whitlock, Michael C

    2015-08-01

    Effective population size is a fundamental parameter in population genetics, evolutionary biology, and conservation biology, yet its estimation can be fraught with difficulties. Several methods to estimate Ne from genetic data have been developed that take advantage of various approaches for inferring Ne . The ability of these methods to accurately estimate Ne , however, has not been comprehensively examined. In this study, we employ seven of the most cited methods for estimating Ne from genetic data (Colony2, CoNe, Estim, MLNe, ONeSAMP, TMVP, and NeEstimator including LDNe) across simulated datasets with populations experiencing migration or no migration. The simulated population demographies are an isolated population with no immigration, an island model metapopulation with a sink population receiving immigrants, and an isolation by distance stepping stone model of populations. We find considerable variance in performance of these methods, both within and across demographic scenarios, with some methods performing very poorly. The most accurate estimates of Ne can be obtained by using LDNe, MLNe, or TMVP; however each of these approaches is outperformed by another in a differing demographic scenario. Knowledge of the approximate demography of population as well as the availability of temporal data largely improves Ne estimates.

  1. Evaluating methods for estimating local effective population size with and without migration.

    PubMed

    Gilbert, Kimberly J; Whitlock, Michael C

    2015-08-01

    Effective population size is a fundamental parameter in population genetics, evolutionary biology, and conservation biology, yet its estimation can be fraught with difficulties. Several methods to estimate Ne from genetic data have been developed that take advantage of various approaches for inferring Ne . The ability of these methods to accurately estimate Ne , however, has not been comprehensively examined. In this study, we employ seven of the most cited methods for estimating Ne from genetic data (Colony2, CoNe, Estim, MLNe, ONeSAMP, TMVP, and NeEstimator including LDNe) across simulated datasets with populations experiencing migration or no migration. The simulated population demographies are an isolated population with no immigration, an island model metapopulation with a sink population receiving immigrants, and an isolation by distance stepping stone model of populations. We find considerable variance in performance of these methods, both within and across demographic scenarios, with some methods performing very poorly. The most accurate estimates of Ne can be obtained by using LDNe, MLNe, or TMVP; however each of these approaches is outperformed by another in a differing demographic scenario. Knowledge of the approximate demography of population as well as the availability of temporal data largely improves Ne estimates. PMID:26118738

  2. Estimating the Size of the Female Sex Worker Population in Kenya to Inform HIV Prevention Programming

    PubMed Central

    Odek, Willis Omondi; Githuka, George N.; Avery, Lisa; Njoroge, Peter K.; Kasonde, Lombe; Gorgens, Marelize; Kimani, Joshua; Gelmon, Lawrence; Gakii, Gloria; Isac, Shajy; Faran, Emmanuel; Musyoki, Helgar; Maina, William; Blanchard, James F.; Moses, Stephen

    2014-01-01

    Background The high burden of HIV infections among female sex workers (FSW) in sub-Saharan Africa has been long recognised, but effective preventive interventions have largely not been taken to scale. We undertook a national geographical mapping exercise in 2011/2012 to assess the locations and population size of FSW in Kenya, to facilitate targeted HIV prevention services for this population. Methods and Findings We used a geographical mapping approach, consisting of interviews with secondary key informants to identify “hot” spots frequented by FSW, their operational dynamics and the estimated numbers of FSW in those spots. This was followed by validation of the estimates through interviews with FSW at each spot identified. The mapping covered Nairobi, the capital city of Kenya, and 50 other major urban centres. In total, 11,609 secondary key informant interviews were conducted to identify FSW spots. Further, a total of 6,360 FSW were interviewed for spot validation purposes. A total of 10,670 spots where FSW congregate were identified. The estimated FSW population in all the towns mapped was 103,298 (range 77,878 to 128, 717). Size estimates in the towns mapped were extended to smaller towns that were not mapped, using a statistical model. The national urban FSW population estimate was 138,420 (range 107, 552 to 169, 288), covering all towns of over 5,000 population. We estimated that approximately 5% of the urban female population of reproductive age in Kenya could be sex workers, which is consistent with previous estimates from other sub-Saharan African countries. Conclusions This study provides the first national level data on the size of the FSW population in Kenya. These data can be used to enhance HIV prevention programme planning and implementation for FSW, to form the basis for impact evaluations, and to improve programme coverage by directing efforts to locations with the greatest need. PMID:24595029

  3. Functional results after cholesteatoma surgery in an adult population using the retrograde mastoidectomy technique.

    PubMed

    Minovi, Amir; Venjacob, Johanna; Volkenstein, Stefan; Dornhoffer, John; Dazert, Stefan

    2014-03-01

    In this retrospective study, we analyzed the functional results after using the retrograde mastoidectomy technique for cholesteatoma removal in an adult patient population. The described technique was used at a tertiary referral center for cholesteatoma removal in 218 adult patients, representing 242 operated ears, with an average follow-up time of 20.3 months. With the retrograde mastoidectomy technique, the cholesteatoma is removed posteriorly through the canal wall, from the epitympanic region toward the mastoid, with the option to reconstruct the posterior bony canal wall or create an open mastoid cavity, depending on the size of the defect. Primary surgery was carried out in 58.7 % ears, with the remaining 41.3 % representing revision surgery. In 151 cases, the posterior canal wall was reconstructed, and in 91 cases a classical CWD with an open mastoid cavity was created. In the majority of the cases (n = 213, 88.0 %), a primary hearing restoration was performed. There were 18 recurrences (12.7 %) in primary cases and 22 recurrences (22 %) in revision surgeries. Ninety percent of the recurrences (36 of 40 cases) occurred within 5 years. A postoperative air-bone gap of less than 20 dB was achieved in 61.6 % of the operated ears. Ears with a reconstructed posterior canal wall had significantly better hearing results than those cases in which a CWD procedure was used (air-bone gap of 17.6 versus 22.5 dB, p < 0.05). The retrograde mastoidectomy technique for cholesteatoma removal resulted in satisfying hearing results in the majority of the cases, with a recurrence rate comparable to the current literature.

  4. Experience in adult population in dengue outbreak in Delhi.

    PubMed

    Tripathi, B K; Gupta, B; Sinha, R S; Prasad, S; Sharma, D K

    1998-03-01

    A dengue outbreak has recently hit the Indian capital. We studied the clinical profile of adult patients. Five hundred and sixty patients of dengue infection were admitted in a specially created ward according to the criteria laid down by WHO. Haematemesis (28.28%), epistaxis (26.78%) and malena (14.28%) were some of the common presentations. Similarly lymphadenopathy, especially cervical (30.89%), palatal rashes (26.96%) and hepatomegaly (23.75%) were the most commonly encountered findings on physical examination. Most of the cases were of dengue fever with haemorrhage and only 2.5% cases were classified under dengue haemorrhagic fever or dengue shock syndrome. The average hospital stay was 3.4 days but only 9.8 hours in the eleven patients who died, suggesting their late arrival in preterminal situation giving little time for resuscitation. Thrombocytopenia was not a feature and only 12.85% patients had platelet count less than 70,000/cmm. Most of the patients who were admitted with thrombocytopenia, showed normalization in their platelet counts in next few days. Serological examination demonstrated evidence of recent dengue infection in 41.17% patients. Few patients required blood or platelet concentrate transfusion. Eleven patients died, three due to DIC, one of intracranial haemorrhage and seven due to massive gastric haemorrhage. Rest of the patients recovered completely. Thus we can conclude that recent outbreak in Delhi was of dengue fever with haemorrhage and mortality was very low in patients who came early to the hospital.

  5. What Is the Prevalence of Adult ADHD? Results of a Population Screen of 966 Adults

    ERIC Educational Resources Information Center

    Faraone, Stephen V.; Biederman, Joseph

    2005-01-01

    To provide a better estimate of the prevalence of ADHD in adulthood, the authors complete a telephone survey of 966 randomly selected adults. They compute two diagnoses from the survey data. Participants meeting "Diagnostic and Statistical Manual of Mental Disorders" (4th ed.) criteria for both childhood and adulthood are defined as narrow ADHD.…

  6. Estimating effective population size from linkage disequilibrium between unlinked loci: theory and application to fruit fly outbreak populations.

    PubMed

    Sved, John A; Cameron, Emilie C; Gilchrist, A Stuart

    2013-01-01

    There is a substantial literature on the use of linkage disequilibrium (LD) to estimate effective population size using unlinked loci. The Ne estimates are extremely sensitive to the sampling process, and there is currently no theory to cope with the possible biases. We derive formulae for the analysis of idealised populations mating at random with multi-allelic (microsatellite) loci. The 'Burrows composite index' is introduced in a novel way with a 'composite haplotype table'. We show that in a sample of diploid size S, the mean value of x2 or r2 from the composite haplotype table is biased by a factor of 1-1/(2S-1)2, rather than the usual factor 1+1/(2S-1) for a conventional haplotype table. But analysis of population data using these formulae leads to Ne estimates that are unrealistically low. We provide theory and simulation to show that this bias towards low Ne estimates is due to null alleles, and introduce a randomised permutation correction to compensate for the bias. We also consider the effect of introducing a within-locus disequilibrium factor to r2, and find that this factor leads to a bias in the Ne estimate. However this bias can be overcome using the same randomised permutation correction, to yield an altered r2 with lower variance than the original r2, and one that is also insensitive to null alleles. The resulting formulae are used to provide Ne estimates on 40 samples of the Queensland fruit fly, Bactrocera tryoni, from populations with widely divergent Ne expectations. Linkage relationships are known for most of the microsatellite loci in this species. We find that there is little difference in the estimated Ne values from using known unlinked loci as compared to using all loci, which is important for conservation studies where linkage relationships are unknown.

  7. Estimating Effective Population Size from Linkage Disequilibrium between Unlinked Loci: Theory and Application to Fruit Fly Outbreak Populations

    PubMed Central

    Sved, John A; Cameron, Emilie C.; Gilchrist, A. Stuart

    2013-01-01

    There is a substantial literature on the use of linkage disequilibrium (LD) to estimate effective population size using unlinked loci. The estimates are extremely sensitive to the sampling process, and there is currently no theory to cope with the possible biases. We derive formulae for the analysis of idealised populations mating at random with multi-allelic (microsatellite) loci. The ‘Burrows composite index’ is introduced in a novel way with a ‘composite haplotype table’. We show that in a sample of diploid size , the mean value of or from the composite haplotype table is biased by a factor of , rather than the usual factor for a conventional haplotype table. But analysis of population data using these formulae leads to estimates that are unrealistically low. We provide theory and simulation to show that this bias towards low estimates is due to null alleles, and introduce a randomised permutation correction to compensate for the bias. We also consider the effect of introducing a within-locus disequilibrium factor to , and find that this factor leads to a bias in the estimate. However this bias can be overcome using the same randomised permutation correction, to yield an altered with lower variance than the original , and one that is also insensitive to null alleles. The resulting formulae are used to provide estimates on 40 samples of the Queensland fruit fly, Bactrocera tryoni, from populations with widely divergent expectations. Linkage relationships are known for most of the microsatellite loci in this species. We find that there is little difference in the estimated values from using known unlinked loci as compared to using all loci, which is important for conservation studies where linkage relationships are unknown. PMID:23894410

  8. Mortality Among Adults With Intellectual Disability in England: Comparisons With the General Population

    PubMed Central

    Hosking, Fay J.; Shah, Sunil M.; Harris, Tess; DeWilde, Stephen; Beighton, Carole; Cook, Derek G.

    2016-01-01

    Objectives. To describe mortality among adults with intellectual disability in England in comparison with the general population. Methods. We conducted a cohort study from 2009 to 2013 using data from 343 general practices. Adults with intellectual disability (n = 16 666; 656 deaths) were compared with age-, gender-, and practice-matched controls (n = 113 562; 1358 deaths). Results. Adults with intellectual disability had higher mortality rates than controls (hazard ratio [HR] = 3.6; 95% confidence interval [CI] = 3.3, 3.9). This risk remained high after adjustment for comorbidity, smoking, and deprivation (HR = 3.1; 95% CI = 2.7, 3.4); it was even higher among adults with intellectual disability and Down syndrome or epilepsy. A total of 37.0% of all deaths among adults with intellectual disability were classified as being amenable to health care intervention, compared with 22.5% in the general population (HR = 5.9; 95% CI = 5.1, 6.8). Conclusions. Mortality among adults with intellectual disability is markedly elevated in comparison with the general population, with more than a third of deaths potentially amenable to health care interventions. This mortality disparity suggests the need to improve access to, and quality of, health care among people with intellectual disability. PMID:27310347

  9. How to control chaotic behaviour and population size with proportional feedback

    NASA Astrophysics Data System (ADS)

    Liz, Eduardo

    2010-01-01

    We study the control of chaos in one-dimensional discrete maps as they often occur in modelling population dynamics. For managing the population, we seek to suppress any possible chaotic behavior, leading the system to a stable equilibrium. In this Letter, we make a rigorous analysis of the proportional feedback method under certain conditions fulfilled by a wide family of maps. We show that it is possible to stabilize the chaotic dynamics towards a globally stable positive equilibrium, that can be chosen among a broad range of possible values. In particular, the size of the population can be enhanced by control in form of population reduction. This paradoxical phenomenon is known as the hydra effect, and it has important implications in the design of strategies in such areas as fishing, pest management, and conservation biology.

  10. Signaling among neighboring plants and the development of size inequalities in plant populations

    SciTech Connect

    Ballare, C.L. |; Scopel, A.L. |; Jordan, E.T.; Vierstra, R.D.

    1994-10-11

    Transgenic tobacco plants that express an oat phytochrome gene (phyA) under control of the cauliflower mosaic virus (CaMV) 35S promoter and display altered photophysiology were used to test the role of light as a vehicle of information in dominance relationships between neighboring plants. Compared with the isogenic wild type, phyA-overexpressing plants showed dramatically reduced morphological responsivity to changes in the red/far red ratio of the incident light and to the proximity of neighboring plants in spacing experiments. In transgenic canopies an increase in stand density caused the small plants of the population to be rapidly suppressed by their neighbors. In wild-type canopies, plants responded to increased density with large morphological changes, and there appeared to be an inverse relationship between the magnitude of this morphological response and the ranking of the individual plant in the population size hierarchy. In these wild-type populations, size inequality increased only moderately with density within the time frame of the experiments. The results suggest that, in crowded stands, the ability of individual plants to acquire information about their light environment via phytochrome plays a central role in driving architectural changes that, at the population level, delay the development of size differences between neighbors.

  11. Climate change influenced female population sizes through time across the Indonesian archipelago.

    PubMed

    Guillot, Elsa G; Tumonggor, Meryanne K; Lansing, J Stephen; Sudoyo, Herawati; Cox, Murray P

    2013-01-01

    Lying at the crossroads of Asia and the Pacific world, the Indonesian archipelago hosts one of the world's richest accumulations of cultural, linguistic, and genetic variation. While the role of human migration into and around the archipelago is now known in some detail, other aspects of Indonesia's complex history are less understood. Here, we focus on population size changes from the first settlement of Indonesia nearly 50 kya up to the historic era. We reconstructed the past effective population sizes of Indonesian women using mitochondrial DNA sequences from 2,104 individuals in 55 village communities on four islands spanning the Indonesian archipelago (Bali, Flores, Sumba, and Timor). We found little evidence for large fluctuations in effective population size. Most communities grew slowly during the late Pleistocene, peaked 15-20 kya, and subsequently declined slowly into the Holocene. This unexpected pattern may reflect population declines caused by the flooding of lowland hunter/gatherer habitat during sea-level rises following the last glacial maximum. PMID:24297223

  12. Climate change influenced female population sizes through time across the Indonesian archipelago.

    PubMed

    Guillot, Elsa G; Tumonggor, Meryanne K; Lansing, J Stephen; Sudoyo, Herawati; Cox, Murray P

    2013-01-01

    Lying at the crossroads of Asia and the Pacific world, the Indonesian archipelago hosts one of the world's richest accumulations of cultural, linguistic, and genetic variation. While the role of human migration into and around the archipelago is now known in some detail, other aspects of Indonesia's complex history are less understood. Here, we focus on population size changes from the first settlement of Indonesia nearly 50 kya up to the historic era. We reconstructed the past effective population sizes of Indonesian women using mitochondrial DNA sequences from 2,104 individuals in 55 village communities on four islands spanning the Indonesian archipelago (Bali, Flores, Sumba, and Timor). We found little evidence for large fluctuations in effective population size. Most communities grew slowly during the late Pleistocene, peaked 15-20 kya, and subsequently declined slowly into the Holocene. This unexpected pattern may reflect population declines caused by the flooding of lowland hunter/gatherer habitat during sea-level rises following the last glacial maximum.

  13. Body size variation of four latitudinally-separated populations of a toad species: age and growth rate as the proximate determinants.

    PubMed

    Yu, Tonglei; Lu, Xin

    2013-09-01

    Age and growth rate are critical parameters determining the body size of adult anurans, which grow indeterminately. Therefore, evaluating their relative importance and selective pressures acting on them may help to explain variation in body size of anurans across geographical populations. Based on the data on body size and skeletochronological age of 4 Asiatic toad (Bufo gargarizans) populations that are widely separated in latitude, the present study showed that toads at the northern extremity of the range were the oldest, on average, and grew relatively fast, toads at the southern end of the range were relatively old but grew fastest, whereas mid-latitude toads were intermediate in both traits. These results indicated that relative contributions of age and growth rate to body size differed among populations. From a life history perspective, greater age attained by toads at higher latitudes should result from delayed maturation, and faster growth from an adaptive response to strong seasonal time constraints; in contrast, selective pressures on the 2 parameters at lower latitudes might be associated, respectively, with low adult death rates and longer favorable growing seasons.

  14. The prevalence of food hypersensitivity in an unselected population of children and adults.

    PubMed

    Osterballe, M; Hansen, T K; Mortz, C G; Høst, A; Bindslev-Jensen, C

    2005-11-01

    A rising prevalence of food hypersensitivity (FHS) and severe allergic reactions to food has been reported the last decade. To estimate the prevalence of FHS to the most common allergenic foods in an unselected population of children and adults. We investigated a cohort of 111 children <3 yr of age, 486 children 3 yr of age, 301 children older than 3 yr of age and 936 adults by questionnaire, skin prick test, histamine release test and specific immunoglobulin E followed by oral challenge to the most common allergenic foods. In total, 698 cases of possible FHS were recorded in 304 (16.6%) participants. The prevalence of FHS confirmed by oral challenge was 2.3% in the children 3 yr of age, 1% in children older than 3 yr of age and 3.2% in adults. The most common allergenic foods were hen's egg affecting 1.6% of the children 3 yr of age and peanut in 0.4% of the adults. Of the adults, 0.2% was allergic to codfish and 0.3% to shrimp, whereas no challenges with codfish and shrimp were positive in the children. The prevalence of clinical reactions to pollen-related foods in pollen-sensitized adults was estimated to 32%. This study demonstrates the prevalence of FHS confirmed by oral challenge to the most common allergenic foods in an unselected population of children and adults.

  15. Multidimensional Clinical Phenotyping of an Adult Cystic Fibrosis Patient Population

    PubMed Central

    Conrad, Douglas J.; Bailey, Barbara A.

    2015-01-01

    Background Cystic Fibrosis (CF) is a multi-systemic disease resulting from mutations in the Cystic Fibrosis Transmembrane Regulator (CFTR) gene and has major manifestations in the sino-pulmonary, and gastro-intestinal tracts. Clinical phenotypes were generated using 26 common clinical variables to generate classes that overlapped quantiles of lung function and were based on multiple aspects of CF systemic disease. Methods The variables included age, gender, CFTR mutations, FEV1% predicted, FVC% predicted, height, weight, Brasfield chest xray score, pancreatic sufficiency status and clinical microbiology results. Complete datasets were compiled on 211 subjects. Phenotypes were identified using a proximity matrix generated by the unsupervised Random Forests algorithm and subsequent clustering by the Partitioning around Medoids (PAM) algorithm. The final phenotypic classes were then characterized and compared to a similar dataset obtained three years earlier. Findings Clinical phenotypes were identified using a clustering strategy that generated four and five phenotypes. Each strategy identified 1) a low lung health scores phenotype, 2) a younger, well-nourished, male-dominated class, 3) various high lung health score phenotypes that varied in terms of age, gender and nutritional status. This multidimensional clinical phenotyping strategy identified classes with expected microbiology results and low risk clinical phenotypes with pancreatic sufficiency. Interpretation This study demonstrated regional adult CF clinical phenotypes using non-parametric, continuous, ordinal and categorical data with a minimal amount of subjective data to identify clinically relevant phenotypes. These studies identified the relative stability of the phenotypes, demonstrated specific phenotypes consistent with published findings and identified others needing further study. PMID:25822311

  16. The relationship between organ dose and patient size in tube current modulated adult thoracic CT scans

    NASA Astrophysics Data System (ADS)

    Khatonabadi, Maryam; Zhang, Di; Yang, Jeffrey; DeMarco, John J.; Cagnon, Chris C.; McNitt-Gray, Michael F.

    2012-03-01

    Recently published AAPM Task Group 204 developed conversion coefficients that use scanner reported CTDIvol to estimate dose to the center of patient undergoing fixed tube current body exam. However, most performed CT exams use TCM to reduce dose to patients. Therefore, the purpose of this study was to investigate the correlation between organ dose and a variety of patient size metrics in adult chest CT scans that use tube current modulation (TCM). Monte Carlo simulations were performed for 32 voxelized models with contoured lungs and glandular breasts tissue, consisting of females and males. These simulations made use of patient's actual TCM data to estimate organ dose. Using image data, different size metrics were calculated, these measurements were all performed on one slice, at the level of patient's nipple. Estimated doses were normalized by scanner-reported CTDIvol and plotted versus different metrics. CTDIvol values were plotted versus different metrics to look at scanner's output versus size. The metrics performed similarly in terms of correlating with organ dose. Looking at each gender separately, for male models normalized lung dose showed a better linear correlation (r2=0.91) with effective diameter, while female models showed higher correlation (r2=0.59) with the anterior-posterior measurement. There was essentially no correlation observed between size and CTDIvol-normalized breast dose. However, a linear relationship was observed between absolute breast dose and size. Dose to lungs and breasts were consistently higher in females with similar size as males which could be due to shape and composition differences between genders in the thoracic region.

  17. Size distribution of retrovirally marked lineages matches prediction from population measurements of cell cycle behavior

    NASA Technical Reports Server (NTRS)

    Cai, Li; Hayes, Nancy L.; Takahashi, Takao; Caviness, Verne S Jr; Nowakowski, Richard S.

    2002-01-01

    Mechanisms that regulate neuron production in the developing mouse neocortex were examined by using a retroviral lineage marking method to determine the sizes of the lineages remaining in the proliferating population of the ventricular zone during the period of neuron production. The distribution of clade sizes obtained experimentally in four different injection-survival paradigms (E11-E13, E11-E14, E11-E15, and E12-E15) from a total of over 500 labeled lineages was compared with that obtained from three models in which the average behavior of the proliferating population [i.e., the proportion of cells remaining in the proliferative population (P) vs. that exiting the proliferative population (Q)] was quantitatively related to lineage size distribution. In model 1, different proportions of asymmetric, symmetric terminal, and symmetric nonterminal cell divisions coexisted during the entire developmental period. In model 2, the developmental period was divided into two epochs: During the first, asymmetric and symmetric nonterminal cell divisions occurred, but, during the second, asymmetric and symmetric terminal cell divisions occurred. In model 3, the shifts in P and Q are accounted for by changes in the proportions of the two types of symmetric cell divisions without the inclusion of any asymmetric cell divisions. The results obtained from the retroviral experiments were well accounted for by model 1 but not by model 2 or 3. These findings demonstrate that: 1) asymmetric and both types of symmetric cell divisions coexist during the entire period of neurogenesis in the mouse, 2) neuron production is regulated in the proliferative population by the independent decisions of the two daughter cells to reenter S phase, and 3) neurons are produced by both asymmetric and symmetric terminal cell divisions. In addition, the findings mean that cell death and/or tangential movements of cells in the proliferative population occur at only a low rate and that there are no

  18. The evolution of harm--effect of sexual conflicts and population size.

    PubMed

    Gay, Laurène; Hosken, David J; Eady, Paul; Vasudev, Ram; Tregenza, Tom

    2011-03-01

    Conflicts of interest between mates can promote the evolution of male traits that reduce female fitness and that drive coevolution between the sexes. The rate of adaptation depends on the intensity of selection and its efficiency, which depends on drift and genetic variability. This leads to the largely untested prediction that coevolutionary adaptations such as those driven by sexual conflict should evolve faster in large populations. We tested this using the bruchid beetle Callosobruchus maculatus, a species where harm inflicted by males is well documented. Although most experimental evolution studies remove sexual conflict, we reintroduced it in populations in which it had been experimentally removed. Both population size and standing genetic variability were manipulated in a factorial experimental design. After 90 generations of relaxed conflict (monogamy), the reintroduction of sexual conflicts for 30 generations favored males that harmed females and females that were more resistant to the genital damage inflicted by males. Males evolved to become more harmful when population size was large rather than when initial genetic variation was enriched. Our study shows that sexual selection can create conditions in which males can benefit from harming females and that selection may tend to be more intense and effective in larger populations.

  19. Resources, key traits and the size of fungal epidemics in Daphnia populations.

    PubMed

    Civitello, David J; Penczykowski, Rachel M; Smith, Aimee N; Shocket, Marta S; Duffy, Meghan A; Hall, Spencer R

    2015-07-01

    Parasites can profoundly affect host populations and ecological communities. Thus, it remains critical to identify mechanisms that drive variation in epidemics. Resource availability can drive epidemics via traits of hosts and parasites that govern disease spread. Here, we map resource-trait-epidemic connections to explain variation in fungal outbreaks (Metschnikowia bicuspidata) in a zooplankton host (Daphnia dentifera) among lakes. We predicted epidemics would grow larger in lakes with more phytoplankton via three energetic mechanisms. First, resources should stimulate Daphnia reproduction, potentially elevating host density. Secondly, resources should boost body size of hosts, enhancing exposure to environmentally distributed propagules through size-dependent feeding. Thirdly, resources should fuel parasite reproduction within hosts. To test these predictions, we sampled 12 natural epidemics and tracked edible algae, fungal infection prevalence, body size, fecundity and density of hosts, as well as within-host parasite loads. Epidemics grew larger in lakes with more algal resources. Structural equation modelling revealed that resource availability stimulated all three traits (host fecundity, host size and parasite load). However, only parasite load connected resources to epidemic size. Epidemics grew larger in more dense Daphnia populations, but host density was unrelated to host fecundity (thus breaking its link to resources). Thus, via energetic mechanisms, resource availability can stimulate key trait(s) governing epidemics in nature. A synthetic focus on resources and resource-trait links could yield powerful insights into epidemics. PMID:25733032

  20. Division synchrony and the dynamics of microbial populations: a size-specific model.

    PubMed

    Gage, T B; Williams, F M; Horton, J B

    1984-12-01

    A discrete, environmentally coupled, size-specific model of microbial population dynamics in continuous culture is presented. It is mathematically simpler than other models based on similar assumptions and lends itself to numerical and analytic solutions. It displays several phenomena which have been reported in the experimental literature but which are not well understood; specifically, a loose relationship between biomass and numbers (i.e., a time lag between mass growth and cell division) and a critical damping of biomass while numbers continue to oscillate. In addition, the model provides several new predictions: The stable biomass distribution is independent of the environmental factors considered in the model and uniformly distributes the biomass among the size classes. The rate of approach to stability and the frequency of waves through the size distributions are a function of the flow rate and the variance in rate of growth and size at division. The model should provide a useful basis for studying the effects of size specificity on the dynamics of microbial populations cultured in chemostats.

  1. Predator-driven brain size evolution in natural populations of Trinidadian killifish (Rivulus hartii).

    PubMed

    Walsh, Matthew R; Broyles, Whitnee; Beston, Shannon M; Munch, Stephan B

    2016-07-13

    Vertebrates exhibit extensive variation in relative brain size. It has long been assumed that this variation is the product of ecologically driven natural selection. Yet, despite more than 100 years of research, the ecological conditions that select for changes in brain size are unclear. Recent laboratory selection experiments showed that selection for larger brains is associated with increased survival in risky environments. Such results lead to the prediction that increased predation should favour increased brain size. Work on natural populations, however, foreshadows the opposite trajectory of evolution; increased predation favours increased boldness, slower learning, and may thereby select for a smaller brain. We tested the influence of predator-induced mortality on brain size evolution by quantifying brain size variation in a Trinidadian killifish, Rivulus hartii, from communities that differ in predation intensity. We observed strong genetic differences in male (but not female) brain size between fish communities; second generation laboratory-reared males from sites with predators exhibited smaller brains than Rivulus from sites in which they are the only fish present. Such trends oppose the results of recent laboratory selection experiments and are not explained by trade-offs with other components of fitness. Our results suggest that increased male brain size is favoured in less risky environments because of the fitness benefits associated with faster rates of learning and problem-solving behaviour. PMID:27412278

  2. Comparison of Statistical Population Reconstruction Using Full and Pooled Adult Age-Class Data

    PubMed Central

    Skalski, John R.; Millspaugh, Joshua J.; Clawson, Michael V.

    2012-01-01

    Background Age-at-harvest data are among the most commonly collected, yet neglected, demographic data gathered by wildlife agencies. Statistical population construction techniques can use this information to estimate the abundance of wild populations over wide geographic areas and concurrently estimate recruitment, harvest, and natural survival rates. Although current reconstruction techniques use full age-class data (0.5, 1.5, 2.5, 3.5, … years), it is not always possible to determine an animal's age due to inaccuracy of the methods, expense, and logistics of sample collection. The ability to inventory wild populations would be greatly expanded if pooled adult age-class data (e.g., 0.5, 1.5, 2.5+ years) could be successfully used in statistical population reconstruction. Methodology/Principal Findings We investigated the performance of statistical population reconstruction models developed to analyze full age-class and pooled adult age-class data. We performed Monte Carlo simulations using a stochastic version of a Leslie matrix model, which generated data over a wide range of abundance levels, harvest rates, and natural survival probabilities, representing medium-to-big game species. Results of full age-class and pooled adult age-class population reconstructions were compared for accuracy and precision. No discernible difference in accuracy was detected, but precision was slightly reduced when using the pooled adult age-class reconstruction. On average, the coefficient of variation increased by 0.059 when the adult age-class data were pooled prior to analyses. The analyses and maximum likelihood model for pooled adult age-class reconstruction are illustrated for a black-tailed deer (Odocoileus hemionus) population in Washington State. Conclusions/Significance Inventorying wild populations is one of the greatest challenges of wildlife agencies. These new statistical population reconstruction models should expand the demographic capabilities of wildlife agencies

  3. Critique and lessons learned from using multiple methods to estimate population size of men who have sex with men in Ghana.

    PubMed

    Quaye, Silas; Fisher Raymond, H; Atuahene, Kyeremeh; Amenyah, Richard; Aberle-Grasse, John; McFarland, Willi; El-Adas, Angela

    2015-02-01

    Population size estimation of key populations at risk of HIV is essential to every national response. We implemented population size estimation of men who have sex with men (MSM) in Ghana using a three-stage approach within the 2011 Ghana Men's Study: during the study's formative assessment, the larger integrated bio-behavioral surveillance (IBBS) survey; and during the stakeholder meeting. We used six methods in combination within the three-stage approach (literature review, mapping with census, unique object multiplier, service multiplier, wisdom of the crowd, and modified Delphi) to generate size estimates from 16 locations (4 IBBS survey sites and 12 other locations) and used the estimates from the 16 sites to extrapolate the total MSM population size of Ghana. We estimated the number of MSM in Ghana to be 30,579 with a plausible range of 21,645-34,470. The overall estimate suggests that the prevalence of MSM in Ghana is 0.48 % of the adult male population. Lessons learned are shared to inform and improve applications of the methods in future studies.

  4. [Regional characteristics of arterial hypertension in adult population of Croatia].

    PubMed

    Erceg, Marijan; Hrabak-Zerjavić, Vlasta; Ivicević Uhernik, Ana

    2007-06-01

    Data collected in the Croatian Health Survey launched in 2003 by the Ministry of Health and Social Welfare were analyzed. The survey included a regionally stratified random sample. Using the method of structured questionnaire and anthropometric measurements (blood pressure, height and weight), data were collected on 9,070 subjects aged >18. The mean systolic and diastolic blood pressure was calculated from two measurements. Inclusion criteria in the group of subjects with elevated blood pressure were the subject's reporting taking antihypertensive medication and/or mean systolic blood pressure > or =140 mm Hg, and/or mean diastolic blood pressure > or =90 mm Hg. Descriptive analysis was done on figures yielded by use of the SPSS software. Subjects with elevated blood pressure accounted for 44.2% (95%CI=42.61-45.85) of study population, with a h gher rate in male (45.6%; 95%= 43.14-48.06) and lower in female subjects (43.0%; 95%CI=41.46-44.55). Croatia was estimated to have 1,538,982 inhabitants with high blood pressure (748,072 males and 790,910 females). The proportion of individuals with elevated blood pressure was highest (78.9%; 95%CI=76.9-81.0; CV=1.32) in the 65 age group, followed by 35-64 age group 46.9% (95% CI=44.8-41.0; CV=2.3), and lowest rate (13.8%; 95%CI=11.1-16.6; CV=10.2) in the 18-34 age group. Regional distribution of high blood pressure was as follows: central Croatia 46.4% (95%CI=42.9-49.9; CV= 3.8), south 45.3% (95%CI= 40.9-49.7; CV=. 5.0), City of Zagreb 44.7% (95%CI= 40.9-48.5; CV= 4.3), east 44.2% (95%CI=40.5-47.8; CV=4.2), north 43.0% (95%CI=40.9-49.7; CV= 5.0), and west 40.5% (95%CI= 36.0-45.0; CV= 5.7). In the female group aged 35-64, regional distribution was as follows: east 52.3% (95%CI=46.0-58.7; CV=6.2), central Croatia 45.4% (95%CI=40.3-50.5; CV=5.7), City of Zagreb 43.5 (95%CI=38.1-48.9; CV=6.4), south 40.7% (95%CI=37.4-44, 0; CV=4.1), north 39.3% (95% CI=33.7-44.8; CV=7.2), and west 35.1% (95%CI=26.1-44.2; CV= 13.1). Differences

  5. Conduct disorder and adult psychiatric diagnoses: associations and gender differences in the U.S. adult population.

    PubMed

    Morcillo, Carmen; Duarte, Cristiane S; Sala, Regina; Wang, Shuai; Lejuez, Carl W; Kerridge, Bradley T; Blanco, Carlos

    2012-03-01

    The authors' objective was to examine the presence of Axis I and II psychiatric disorders among adult males and females with a history in childhood and/or adolescence of conduct disorder (CD). Data were derived from a large national sample of the U.S. population. Face-to-face interviews of more than 34,000 adults ages 18 years and older were conducted during 2004-2005 using the Alcohol Use Disorder and Associated Disabilities Interview Schedule-DSM-IV Version. After adjusting for sociodemographic characteristics and psychiatric comorbidity, CD was associated with all Axis I and II disorders, particularly substance use disorders (SUD), bipolar disorder, and histrionic personality disorders. After adjusting for gender differences in the general population, men had significantly greater odds of social anxiety disorder and paranoid personality disorder, whereas women were more likely to have SUD. Furthermore, there was dose-response relationship between number of CD symptoms and risk for most psychiatric disorders. From a clinical standpoint, knowledge of the gender differences in associations of CD with other psychiatric disorders in adulthood may be informative of developmental pathways of the disorder, and of possible gender-specific risk factors. Early recognition and treatment of CD may help prevent the development of adult-onset disorders.

  6. Asymptotic Distributions of Coalescence Times and Ancestral Lineage Numbers for Populations with Temporally Varying Size

    PubMed Central

    Chen, Hua; Chen, Kun

    2013-01-01

    The distributions of coalescence times and ancestral lineage numbers play an essential role in coalescent modeling and ancestral inference. Both exact distributions of coalescence times and ancestral lineage numbers are expressed as the sum of alternating series, and the terms in the series become numerically intractable for large samples. More computationally attractive are their asymptotic distributions, which were derived in Griffiths (1984) for populations with constant size. In this article, we derive the asymptotic distributions of coalescence times and ancestral lineage numbers for populations with temporally varying size. For a sample of size n, denote by Tm the mth coalescent time, when m + 1 lineages coalesce into m lineages, and An(t) the number of ancestral lineages at time t back from the current generation. Similar to the results in Griffiths (1984), the number of ancestral lineages, An(t), and the coalescence times, Tm, are asymptotically normal, with the mean and variance of these distributions depending on the population size function, N(t). At the very early stage of the coalescent, when t → 0, the number of coalesced lineages n − An(t) follows a Poisson distribution, and as m → n, n(n−1)Tm/2N(0) follows a gamma distribution. We demonstrate the accuracy of the asymptotic approximations by comparing to both exact distributions and coalescent simulations. Several applications of the theoretical results are also shown: deriving statistics related to the properties of gene genealogies, such as the time to the most recent common ancestor (TMRCA) and the total branch length (TBL) of the genealogy, and deriving the allele frequency spectrum for large genealogies. With the advent of genomic-level sequencing data for large samples, the asymptotic distributions are expected to have wide applications in theoretical and methodological development for population genetic inference. PMID:23666939

  7. Group selection on population size affects life-history patterns in the entomopathogenic nematode Steinernema carpocapsae.

    PubMed

    Bashey, Farrah; Lively, Curtis M

    2009-05-01

    Selection is recognized to operate on multiple levels. In disease organisms, selection among hosts is thought to provide an important counterbalance to selection for faster growth within hosts. We performed three experiments, each selecting for a divergence in group size in the entomopathogenic nematode, Steinernema carpocapsae. These nematodes infect and kill insect larvae, reproduce inside the host carcass, and emerge as infective juveniles. We imposed selection on group size by selecting among hosts for either high or low numbers of emerging nematodes. Our goal was to determine whether this trait could respond to selection at the group level, and if so, to examine what other traits would evolve as correlated responses. One of the three experiments showed a significant response to group selection. In that experiment, the high-selected treatment consistently produced more emerging nematodes per host than the low-selected treatment. In addition, nematodes were larger and they emerged later from hosts in the low-selected lines. Despite small effective population sizes, the effects of inbreeding were small in this experiment. Thus, selection among hosts can be effective, leading to both a direct evolutionary response at the population level, as well as to correlated responses in populational and individual traits.

  8. Mixture models for estimating the size of a closed population when capture rates vary among individuals

    USGS Publications Warehouse

    Dorazio, R.M.; Royle, J. Andrew

    2003-01-01

    We develop a parameterization of the beta-binomial mixture that provides sensible inferences about the size of a closed population when probabilities of capture or detection vary among individuals. Three classes of mixture models (beta-binomial, logistic-normal, and latent-class) are fitted to recaptures of snowshoe hares for estimating abundance and to counts of bird species for estimating species richness. In both sets of data, rates of detection appear to vary more among individuals (animals or species) than among sampling occasions or locations. The estimates of population size and species richness are sensitive to model-specific assumptions about the latent distribution of individual rates of detection. We demonstrate using simulation experiments that conventional diagnostics for assessing model adequacy, such as deviance, cannot be relied on for selecting classes of mixture models that produce valid inferences about population size. Prior knowledge about sources of individual heterogeneity in detection rates, if available, should be used to help select among classes of mixture models that are to be used for inference.

  9. N-mixture models for estimating population size from spatially replicated counts

    USGS Publications Warehouse

    Royle, J. Andrew

    2004-01-01

    Spatial replication is a common theme in count surveys of animals. Such surveys often generate sparse count data from which it is difficult to estimate population size while formally accounting for detection probability. In this article, i describe a class of models (n-mixture models) which allow for estimation of population size from such data. The key idea is to view site-specific population sizes, n, as independent random variables distributed according to some mixing distribution (e.g., Poisson). Prior parameters are estimated from the marginal likelihood of the data, having integrated over the prior distribution for n. Carroll and lombard (1985, journal of american statistical association 80, 423-426) proposed a class of estimators based on mixing over a prior distribution for detection probability. Their estimator can be applied in limited settings, but is sensitive to prior parameter values that are fixed a priori. Spatial replication provides additional information regarding the parameters of the prior distribution on n that is exploited by the n-mixture models and which leads to reasonable estimates of abundance from sparse data. A simulation study demonstrates superior operating characteristics (bias, confidence interval coverage) of the n-mixture estimator compared to the caroll and lombard estimator. Both estimators are applied to point count data on six species of birds illustrating the sensitivity to choice of prior on p and substantially different estimates of abundance as a consequence.

  10. Effect size of memory deficits in mice with adult-onset P301L tau expression.

    PubMed

    Hunsberger, Holly C; Rudy, Carolyn C; Weitzner, Daniel S; Zhang, Chong; Tosto, David E; Knowlan, Kevin; Xu, Ying; Reed, Miranda N

    2014-10-01

    Transgenic mice expressing mutations in tau have yielded essential discoveries for Alzheimer's disease. One of the most commonly used tau mouse models is the tet-off Tg(tauP301L)4510 model that expresses P301L human tau driven by the calcium-calmodulin kinase IIα (CaMKIIα) promoter system. Tau expression in this model is regulatable, allowing for suppression of mutant tau expression until adulthood and prevention of possible developmental alterations resulting from P301L tau expression during development. Here, we compared the effect and sample sizes needed for three learning and memory tasks in mice with adult-onset P301L tau expression. Our findings indicate that the Incremental Repeated Acquisition (IRA) and trace fear conditioning tasks, neither of which have previously been published with these mice, were highly sensitive to P301L tau expression, whereas the Morris water maze, the most commonly used task with this model, was the least sensitive. Memory deficits were observed at a time when tau pathology was subtle and prior to readily detectable neuronal loss. Thus, we provide essential information (effect and sample sizes needed) for establishing experimental designs at a time point when memory deficits are likely to go undetected if inadequate sample sizes are used. Our work also suggests the tet-off Tg4510 model provides a way to avoid mutant tau expression during the perinatal and early postnatal stages, thereby preventing possible developmental alterations unrelated to Alzheimer's disease.

  11. Relationships among vocabulary size, nonverbal cognition, and spoken word recognition in adults with cochlear implants

    NASA Astrophysics Data System (ADS)

    Collison, Elizabeth A.; Munson, Benjamin; Carney, Arlene E.

    2002-05-01

    Recent research has attempted to identify the factors that predict speech perception performance among users of cochlear implants (CIs). Studies have found that approximately 20%-60% of the variance in speech perception scores can be accounted for by factors including duration of deafness, etiology, type of device, and length of implant use, leaving approximately 50% of the variance unaccounted for. The current study examines the extent to which vocabulary size and nonverbal cognitive ability predict CI listeners' spoken word recognition. Fifteen postlingually deafened adults with nucleus or clarion CIs were given standardized assessments of nonverbal cognitive ability and expressive vocabulary size: the Expressive Vocabulary Test, the Test of Nonverbal Intelligence-III, and the Woodcock-Johnson-III Test of Cognitive Ability, Verbal Comprehension subtest. Two spoken word recognition tasks were administered. In the first, listeners identified isophonemic CVC words. In the second, listeners identified gated words varying in lexical frequency and neighborhood density. Analyses will examine the influence of lexical frequency and neighborhood density on the uniqueness point in the gating task, as well as relationships among nonverbal cognitive ability, vocabulary size, and the two spoken word recognition measures. [Work supported by NIH Grant P01 DC00110 and by the Lions 3M Hearing Foundation.

  12. Selection on incremental variation of eye size in a wild population of Daphnia.

    PubMed

    Brandon, C S; James, T; Dudycha, J L

    2015-11-01

    Several studies of eye morphology have analysed macroevolutionary patterns in the diversity of eyes, and although these studies are often linked to environment or behaviour, they provide only indirect evidence of selection. Specific data to show the microevolutionary potential for adaptation by natural selection in eye morphology have been lacking. We document directional selection on eye size, an important determinant of visual capabilities, in a wild population of the freshwater microcrustacean Daphnia. We show that even slight changes in eye size may have major consequences for fitness. An increase in eye diameter of 19.9 μm - slightly more than one standard deviation - is associated with an increase in clutch size of one egg, or an increase of nearly 20% of the mean clutch size. Furthermore, relative eye size is genetically variable and thus could evolve in response to the observed selective pressure. We conclude that selection on incremental variation in eye size may have led to differences observed on broader taxonomic scales.

  13. Genomic diversity of cultivable Lactobacillus populations residing in the neonatal and adult gastrointestinal tract.

    PubMed

    Wall, Rebecca; Fitzgerald, Gerald; Hussey, Séamus; Ryan, Tony; Murphy, Brendan; Ross, Paul; Stanton, Catherine

    2007-01-01

    The objective of this study was to investigate the cultivable Lactobacillus population in adult and infant faecal material to identify strains shared across a number of individuals. A range of lactobacilli isolated on Lactobacillus-selective agar from faeces of 16 infants and 11 adults were genetically fingerprinted and further characterized by 16S rRNA gene sequencing. The relatedness of all the Lactobacillus strains isolated to known species was also determined both genetically and phenotypically. This study revealed that the human intestine is initially colonized by only a few (1-2) different cultivable strains whereas in adults the pattern becomes more complex with a higher diversity of strains. The adult samples contained three genetically distinct Lactobacillus strains in some cases, while infant samples generally harboured only one dominant Lactobacillus strain. Moreover, the species in general appeared to differ with Lactobacillus rhamnosus and Lactobacillus casei/paracasei found mainly in adults, whereas Lactobacillus gasseri and Lactobacillus salivarius were more commonly isolated in infant samples. The data reaffirm the differences in Lactobacillus populations both between individual subjects and between the infant and adult, with an overall change in the diversity and complexity from early stages of life to adulthood.

  14. Meet the parents? Family size and the geographic proximity between adult children and older mothers in Sweden.

    PubMed

    Holmlund, Helena; Rainer, Helmut; Siedler, Thomas

    2013-06-01

    The aim of this study is to estimate the causal effect of family size on the proximity between older mothers and adult children by using a large administrative data set from Sweden. Our main results show that adult children in Sweden are not constrained by sibship size in choosing where to live: for families with more than one child, sibship size does not affect child-mother proximity. For aging parents, however, having fewer children reduces the probability of having at least one child living nearby, which is likely to have consequences for the intensity of intergenerational contact and eldercare.

  15. Prevalence of Active and Passive Smoking among Adult Population: Findings of a Population-Based Survey in Kerman (KERCADRS), Iran

    PubMed Central

    Salimzadeh, Hamideh; Najafipour, Hamid; Mirzaiepour, Fatemeh; Navadeh, Soodabeh; Shadkam-Farrokhi, Mitra; Mirzazadeh, Ali

    2016-01-01

    Background Smoking is one of the major modifiable risk factors for non-communicable diseases. Our aim was to report the pattern of active and passive smoking using the data collected through a population-base household survey in Kerman, Iran [(KERCADRS) Kerman Coronary Artery Disease Risk Factors Study]. Methods Using a cluster random sampling design, we recruited 5900 adult persons (15-75 years old) into our survey. After consenting, every participant was interviewed by a trained interviewer. The section for smoking included questions about daily (smoking at least one cigarette per day), non-daily, past and passive cigarette smoking as well as the duration of the exposure. We used Kerman population distribution (as the target population) to adjust our estimates using direct standardization method. Findings Overall, 8.3% of study participants (15.5% in men vs. 0.8% in women, P = 0.010) reported themselves as daily smokers and an additional 1.7% (2.9% in men vs. 0.4% in women, P = 0.010) as non-daily smokers. The passive smoking was common in total (27.5%), while women experienced more exposure than men (30.1% vs. 25.0%, P = 0.010). In daily smokers, 3.2% smoked more than 20 cigarettes per day. Among passive smokers, 62.6% were exposed to cigarette smoke more than 6 days per week. Conclusion Smoking is pretty common among adult populations, particularly in men. A majority of tobacco-free young adult women are exposed to passive smoking. Age and gender oriented interventions are required to change this risk pattern in Kerman community to prevent from further smoking related morbidities and mortalities. PMID:27274789

  16. Legacy lost: genetic variability and population size of extirpated US grey wolves (Canis lupus).

    PubMed

    Leonard, Jennifer A; Vilà, Carles; Wayne, Robert K

    2005-01-01

    By the mid 20th century, the grey wolf (Canis lupus) was exterminated from most of the conterminous United States (cUS) and Mexico. However, because wolves disperse over long distances, extant populations in Canada and Alaska might have retained a substantial proportion of the genetic diversity once found in the cUS. We analysed mitochondrial DNA sequences of 34 pre-extermination wolves and found that they had more than twice the diversity of their modern conspecifics, implying a historic population size of several hundred thousand wolves in the western cUS and Mexico. Further, two-thirds of the haplotypes found in the historic sample are unique. Sequences from Mexican grey wolves (C. l. baileyi) and some historic grey wolves defined a unique southern clade supporting a much wider geographical mandate for the reintroduction of Mexican wolves than currently planned. Our results highlight the genetic consequences of population extinction within Ice Age refugia and imply that restoration goals for grey wolves in the western cUS include far less area and target vastly lower population sizes than existed historically.

  17. Low effective population size and evidence for inbreeding in an overexploited flatfish, plaice (Pleuronectes platessa L.)

    PubMed Central

    Hoarau, Galice; Boon, Eva; Jongma, Dorris N; Ferber, Steven; Palsson, Jonbjorn; Van der Veer, Henk W; Rijnsdorp, Adriaan D; Stam, Wytze T; Olsen, Jeanine L

    2005-01-01

    Overexploitation and subsequent collapse of major worldwide fisheries has made it clear that marine stocks are not inexhaustible. Unfortunately, the perception remains that marine fishes are resilient to large population reductions, as even a commercially ‘collapsed’ stock will still consist of millions of individuals. Coupled with this notion is the idea that fisheries can, therefore, have little effect on the genetic diversity of stocks. We used DNA from archived otoliths collected between 1924 and 1972 together with 2002 juvenile's tissue to estimate effective population size (Ne) in plaice (Pleuronectes platessa). Ne was estimated at 20 000 in the North Sea and 2000 in Iceland. These values are five orders of magnitude smaller than the estimated census size for the two locations. Populations examined between 1924 and 1960 were in Hardy–Weinberg equilibrium, whereas populations examined after approximately 1970 were not. Extensive testing was performed to rule out genotyping artefacts and Wahlund effects. The significant heterozygote deficiencies found from 1970 onward were attributed to inbreeding. The emergence of inbreeding between 1950 and 1970 coincides with the increase in fishing mortality after World War II. Although the biological mechanisms remain speculative, our demonstration of inbreeding signals the need for understanding the social and mating behaviour in commercially important fishes. PMID:15799945

  18. The Effects of Population Size Histories on Estimates of Selection Coefficients from Time-Series Genetic Data

    PubMed Central

    Jewett, Ethan M.; Steinrücken, Matthias; Song, Yun S.

    2016-01-01

    Many approaches have been developed for inferring selection coefficients from time series data while accounting for genetic drift. These approaches have been motivated by the intuition that properly accounting for the population size history can significantly improve estimates of selective strengths. However, the improvement in inference accuracy that can be attained by modeling drift has not been characterized. Here, by comparing maximum likelihood estimates of selection coefficients that account for the true population size history with estimates that ignore drift by assuming allele frequencies evolve deterministically in a population of infinite size, we address the following questions: how much can modeling the population size history improve estimates of selection coefficients? How much can mis-inferred population sizes hurt inferences of selection coefficients? We conduct our analysis under the discrete Wright–Fisher model by deriving the exact probability of an allele frequency trajectory in a population of time-varying size and we replicate our results under the diffusion model. For both models, we find that ignoring drift leads to estimates of selection coefficients that are nearly as accurate as estimates that account for the true population history, even when population sizes are small and drift is high. This result is of interest because inference methods that ignore drift are widely used in evolutionary studies and can be many orders of magnitude faster than methods that account for population sizes. PMID:27550904

  19. Reconstructing the size distribution of the small body population in the Solar System

    NASA Astrophysics Data System (ADS)

    Lambrechts, Michiel; Morbidelli, Alessandro

    2016-10-01

    The size distributions of the populations of small bodies in the solar system (the asteroid belt, the hot Kuiper belt and the cold Kuiper belt) show a striking similarity: they all show an elbow at a diameter of about D=100km. At D<100km, all size distributions have the same slope, dictated by collisional equilibrium. At D>100km, the slopes are different, the cold Kuiper belt having the steepest slope, while the hot Kuiper belt and the asteroid belt have progressively more shallow slopes. Moreover, the asteroid belt and hot Kuiper belt show a turnover to a shallow size distribution at sizes larger than D=300-500km. Johansen et al. (2015) explained the elbow and the transition to a steeper slope assuming that the original planetesimals had D<100km and that they grew further by the process of pebble accretion, the sweep up of small particles aided by gas drag. However, the origin of the differences between the slopes of the three populations remained unclear.Here we investigate the problem using a particle-in-a-box code, that treats collisional coagulation, fragmentation, dynamical stirring and damping, to which we have added growth by pebble accretion for objects with possibly eccentric and inclined orbits.We show that the size distribution above D=100km is set by a combination of planetesimal collisions and the sweeping up of pebbles. Thus, the final slopes are diagnostic of the collisionial rate and the initial total mass of the planetesimal population. The size distribution for the largest asteroids and hot Kuiper belt objects are consistent with growth dominated by the accretion of pebbles. The observed size distributions also places constraints on the dominant particle size, the level of midplane turbulence and nebular conditions at different orbital radii in the Solar nebula. Our findings hint that the asteroid belt largely formed close to the dissipation of the gas disc and that its final total mass was comparable to that of the Earth.

  20. The Contributions of Phonological and Morphological Awareness to Literacy Skills in the Adult Basic Education Population

    ERIC Educational Resources Information Center

    Fracasso, Lucille E.; Bangs, Kathryn; Binder, Katherine S.

    2016-01-01

    The Adult Basic Education (ABE) population consists of a wide range of abilities with needs that may be unique to this set of learners. The purpose of this study was to better understand the relative contributions of phonological decoding and morphological awareness to spelling, vocabulary, and comprehension across a sample of ABE students. In…

  1. HIV/AIDS Misconceptions among Latinos: Findings from a Population-Based Survey of California Adults

    ERIC Educational Resources Information Center

    Ritieni, Assunta; Moskowitz, Joel; Tholandi, Maya

    2008-01-01

    Misconceptions about HIV/AIDS among Latino adults (N=454) in California were examined using data from a population-based telephone survey conducted in 2000. Common misconceptions concerning modes of HIV transmission included transmission via mosquito or animal bite (64.1%), public facilities (48.3%), or kissing someone on the cheek (24.8%). A…

  2. Participation in Adult Education: Current Population Survey, May 1984 [machine-readable data file].

    ERIC Educational Resources Information Center

    Bureau of the Census (DOC), Washington, DC. Data User Services Div.

    The "Participation in Adult Education" machine-readable data file (MRDF) is prepared triennially for the Center for Education Statistics (CES) by the Bureau of the Census, as a supplement to its regular "Current Population Survey" (sponsored by the Bureau of Labor Statistics). Previous specialized surveys in this series have been conducted in…

  3. Extent of Linkage Disequilibrium and Effective Population Size in Four South African Sanga Cattle Breeds

    PubMed Central

    Makina, Sithembile O.; Taylor, Jeremy F.; van Marle-Köster, Este; Muchadeyi, Farai C.; Makgahlela, Mahlako L.; MacNeil, Michael D.; Maiwashe, Azwihangwisi

    2015-01-01

    Knowledge on the extent of linkage disequilibrium (LD) in livestock populations is essential to determine the minimum distance between markers required for effective coverage when conducting genome-wide association studies (GWAS). This study evaluated the extent of LD, persistence of allelic phase and effective population size (Ne) for four Sanga cattle breeds in South Africa including the Afrikaner (n = 44), Nguni (n = 54), Drakensberger (n = 47), and Bonsmara breeds (n = 46), using Angus (n = 31) and Holstein (n = 29) as reference populations. We found that moderate LD extends up to inter-marker distances of 40–60 kb in Angus (0.21) and Holstein (0.21) and up to 100 kb in Afrikaner (0.20). This suggests that genomic selection and association studies performed within these breeds using an average inter-marker r2≥ 0.20 would require about 30,000–50,000 SNPs. However, r2≥ 0.20 extended only up to 10–20 kb in the Nguni and Drakensberger and 20–40 kb in the Bonsmara indicating that 75,000 to 150,000 SNPs would be necessary for GWAS in these breeds. Correlation between alleles at contiguous loci indicated that phase was not strongly preserved between breeds. This suggests the need for breed-specific reference populations in which a much greater density of markers should be scored to identify breed specific haplotypes which may then be imputed into multi-breed commercial populations. Analysis of effective population size based on the extent of LD, revealed Ne = 95 (Nguni), Ne = 87 (Drakensberger), Ne = 77 (Bonsmara), and Ne = 41 (Afrikaner). Results of this study form the basis for implementation of genomic selection programs in the Sanga breeds of South Africa. PMID:26648975

  4. On the importance of being structured: instantaneous coalescence rates and human evolution--lessons for ancestral population size inference?

    PubMed

    Mazet, O; Rodríguez, W; Grusea, S; Boitard, S; Chikhi, L

    2016-04-01

    Most species are structured and influenced by processes that either increased or reduced gene flow between populations. However, most population genetic inference methods assume panmixia and reconstruct a history characterized by population size changes. This is potentially problematic as population structure can generate spurious signals of population size change through time. Moreover, when the model assumed for demographic inference is misspecified, genomic data will likely increase the precision of misleading if not meaningless parameters. For instance, if data were generated under an n-island model (characterized by the number of islands and migrants exchanged) inference based on a model of population size change would produce precise estimates of a bottleneck that would be meaningless. In addition, archaeological or climatic events around the bottleneck's timing might provide a reasonable but potentially misleading scenario. In a context of model uncertainty (panmixia versus structure) genomic data may thus not necessarily lead to improved statistical inference. We consider two haploid genomes and develop a theory that explains why any demographic model with structure will necessarily be interpreted as a series of changes in population size by inference methods ignoring structure. We formalize a parameter, the inverse instantaneous coalescence rate, and show that it is equivalent to a population size only in panmictic models, and is mostly misleading for structured models. We argue that this issue affects all population genetics methods ignoring population structure which may thus infer population size changes that never took place. We apply our approach to human genomic data. PMID:26647653

  5. Nutrition Considerations for the Growing Population of Older Adults With Diabetes

    PubMed Central

    Stanley, Kathleen

    2014-01-01

    In Brief The growing older adult population and its higher incidence of diabetes are creating demands on health care providers to address the special needs of these patients. Because nutrition is essential to the proper treatment and self-management of diabetes, clinicians must develop and adopt various strategies to address some of the common nutritional, lifestyle, and self-management barriers that older adults face. Nutrition assessments of older adults with diabetes should be comprehensive, with attention to each patient’s unique nutritional needs. Constructing a realistic nutrition care plan is essential for success. This article addresses some of the key nutrition-related aspects of diabetes self-care in older adults with diabetes. PMID:26246753

  6. Randomized Controlled Trial of the ShangRing for Adult Medical Male Circumcision: Safety, Effectiveness, and Acceptability of Using 7 Versus 14 Device Sizes

    PubMed Central

    Zulu, Robert; Linyama, David; Long, Sarah; Nonde, Thikazi Jere; Lai, Jaim Jou; Kashitala, Joshua; Veena, Valentine; Kasonde, Prisca

    2016-01-01

    Objectives: To assess the safety, effectiveness, and acceptability of providing a reduced number of ShangRing sizes for adult voluntary medical male circumcision (VMMC) within routine service delivery in Lusaka, Zambia. Methods: We conducted a randomized controlled trial and enrolled 500 HIV-negative men aged 18–49 years at 3 clinics. Participants were randomized to 1 of 2 study arms (Standard Sizing arm vs Modified Sizing arm) in a 1:1 ratio. All 14 adult ShangRing sizes (40–26 mm inner diameter, each varying by 1 mm) were available in the Standard Sizing arm; the Modified Sizing arm used every other size (40, 38, 36, 34, 32, 30, 28 mm inner diameter). Each participant was scheduled for 2 follow-up visits: the removal visit (day 7 after placement) and the healing check visit (day 42 after placement), when they were evaluated for adverse events (AEs), pain, and healing. Results: Four hundred and ninety-six men comprised the analysis population, with 255 in the Standard Sizing arm and 241 in the Modified Sizing arm. Three men experienced a moderate or severe AEs (0.6%), including 2 in the Standard Sizing arm (0.8%) and 1 in the Modified Sizing arm (0.4%). 73.2% of participants were completely healed at the scheduled day 42 healing check visit, with similar percentages across study arms. Virtually all (99.6%) men, regardless of study arm, stated that they were very satisfied or satisfied with the appearance of their circumcised penis, and 98.6% stated that they would recommend ShangRing circumcision to family/friends. Conclusions: The moderate/severe AE rate was low and similar in the 2 study arms, suggesting that provision of one-half the number of adult device sizes is sufficient for safe service delivery. Effectiveness, time to healing, and acceptability were similar in the study arms. The simplicity of the ShangRing technique, and its relative speed, could facilitate VMMC program goals. In addition, sufficiency of fewer device sizes would simplify logistics

  7. Genetic effective size of a wild primate population: influence of current and historical demography.

    PubMed

    Storz, Jay F; Ramakrishnan, Uma; Alberts, Susan C

    2002-04-01

    A comprehensive assessment of the determinants of effective population size (N(e)) requires estimates of variance in lifetime reproductive success and past changes in census numbers. For natural populations, such information can be best obtained by combining longitudinal data on individual life histories and genetic marker-based inferences of demographic history. Independent estimates of the variance effective size (N(ev), obtained from life-history data) and the inbreeding effective size (N((eI), obtained from genetic data) provide a means of disentangling the effects of current and historical demography. The purpose of this study was to assess the demographic determinants of N(e) in one of the most intensively studied natural populations of a vertebrate species: the population of savannah baboons (Papio cynocephalus) in the Amboseli Basin, southern Kenya. We tested the hypotheses that N(eV) < N < N(eI) (where N = population census number) due to a recent demographic bottleneck. N(eV) was estimated using a stochastic demographic model based on detailed life-history data spanning a 28-year period. Using empirical estimates of age-specific rates of survival and fertility for both sexes, individual-based simulations were used to estimate the variance in lifetime reproductive success. The resultant values translated into an N(eV)/N estimate of 0.329 (SD = 0.116, 95% CI = 0.172-0.537). Historical N(eI), was estimated from 14-locus microsatellite genotypes using a coalescent-based simulation model. Estimates of N(eI) were 2.2 to 7.2 times higher than the contemporary census number of the Amboseli baboon population. In addition to the effects of immigration, the disparity between historical N(eI) and contemporary N is likely attributable to the time lag between the recent drop in census numbers and the rate of increase in the average probability of allelic identity-by-descent. Thus, observed levels of genetic diversity may primarily reflect the population's prebottleneck

  8. Effect of distance-related heterogeneity on population size estimates from point counts

    USGS Publications Warehouse

    Efford, Murray G.; Dawson, Deanna K.

    2009-01-01

    Point counts are used widely to index bird populations. Variation in the proportion of birds counted is a known source of error, and for robust inference it has been advocated that counts be converted to estimates of absolute population size. We used simulation to assess nine methods for the conduct and analysis of point counts when the data included distance-related heterogeneity of individual detection probability. Distance from the observer is a ubiquitous source of heterogeneity, because nearby birds are more easily detected than distant ones. Several recent methods (dependent double-observer, time of first detection, time of detection, independent multiple-observer, and repeated counts) do not account for distance-related heterogeneity, at least in their simpler forms. We assessed bias in estimates of population size by simulating counts with fixed radius w over four time intervals (occasions). Detection probability per occasion was modeled as a half-normal function of distance with scale parameter sigma and intercept g(0) = 1.0. Bias varied with sigma/w; values of sigma inferred from published studies were often 50% for a 100-m fixed-radius count. More critically, the bias of adjusted counts sometimes varied more than that of unadjusted counts, and inference from adjusted counts would be less robust. The problem was not solved by using mixture models or including distance as a covariate. Conventional distance sampling performed well in simulations, but its assumptions are difficult to meet in the field. We conclude that no existing method allows effective estimation of population size from point counts.

  9. Using Wolbachia Releases to Estimate Aedes aegypti (Diptera: Culicidae) Population Size and Survival

    PubMed Central

    Garcia, Gabriela de Azambuja; dos Santos, Lilha Maria Barbosa; Villela, Daniel Antunes Maciel; Maciel-de-Freitas, Rafael

    2016-01-01

    Mosquitoes carrying the endosymbiont bacterium Wolbachia have been deployed in field trials as a biological control intervention due to Wolbachia effects on reducing transmission of arboviruses. We performed mark, release and recapture (MRR) experiments using Wolbachia as an internal marker with daily collections with BG-Traps during the first two weeks of releases in Rio de Janeiro, Brazil. The MRR design allowed us to investigate two critical parameters that determine whether Wolbachia would successful invade a field population: the probability of daily survival (PDS) of Wolbachia-infected Aedes aegypti females, and the wild population density during releases. Released females had a PDS of 0.82 and 0.89 in the first and second weeks, respectively, immediately after releases, which is well within the range of previous estimates of survivorship of wild mosquitoes in Rio de Janeiro. Abundance estimation of wild population varied up to 10-fold higher depending on the estimation method used (634–3565 females on the average-difference model to 6365–16188 females according to Lincoln-Petersen). Wolbachia-released mosquitoes were lower than the density estimation of their wild counterparts, irrespectively of the model used. Individually screening mosquitoes for the presence of Wolbachia reduced uncertainty on abundance estimations due to fluctuation in capturing per week. A successful invasion into local population requires Ae. aegypti fitness is unaffected by Wolbachia presence, but also reliable estimates on the population size of wild mosquitoes. PMID:27479050

  10. The Cultural Evolution of Human Communication Systems in Different Sized Populations: Usability Trumps Learnability

    PubMed Central

    Fay, Nicolas; Ellison, T. Mark

    2013-01-01

    This study examines the intergenerational transfer of human communication systems. It tests if human communication systems evolve to be easy to learn or easy to use (or both), and how population size affects learnability and usability. Using an experimental-semiotic task, we find that human communication systems evolve to be easier to use (production efficiency and reproduction fidelity), but harder to learn (identification accuracy) for a second generation of naïve participants. Thus, usability trumps learnability. In addition, the communication systems that evolve in larger populations exhibit distinct advantages over those that evolve in smaller populations: the learnability loss (from the Initial signs) is more muted and the usability benefits are more pronounced. The usability benefits for human communication systems that evolve in a small and large population is explained through guided variation reducing sign complexity. The enhanced performance of the communication systems that evolve in larger populations is explained by the operation of a content bias acting on the larger pool of competing signs. The content bias selects for information-efficient iconic signs that aid learnability and enhance usability. PMID:23967243

  11. The cultural evolution of human communication systems in different sized populations: usability trumps learnability.

    PubMed

    Fay, Nicolas; Ellison, T Mark

    2013-01-01

    This study examines the intergenerational transfer of human communication systems. It tests if human communication systems evolve to be easy to learn or easy to use (or both), and how population size affects learnability and usability. Using an experimental-semiotic task, we find that human communication systems evolve to be easier to use (production efficiency and reproduction fidelity), but harder to learn (identification accuracy) for a second generation of naïve participants. Thus, usability trumps learnability. In addition, the communication systems that evolve in larger populations exhibit distinct advantages over those that evolve in smaller populations: the learnability loss (from the Initial signs) is more muted and the usability benefits are more pronounced. The usability benefits for human communication systems that evolve in a small and large population is explained through guided variation reducing sign complexity. The enhanced performance of the communication systems that evolve in larger populations is explained by the operation of a content bias acting on the larger pool of competing signs. The content bias selects for information-efficient iconic signs that aid learnability and enhance usability. PMID:23967243

  12. The cultural evolution of human communication systems in different sized populations: usability trumps learnability.

    PubMed

    Fay, Nicolas; Ellison, T Mark

    2013-01-01

    This study examines the intergenerational transfer of human communication systems. It tests if human communication systems evolve to be easy to learn or easy to use (or both), and how population size affects learnability and usability. Using an experimental-semiotic task, we find that human communication systems evolve to be easier to use (production efficiency and reproduction fidelity), but harder to learn (identification accuracy) for a second generation of naïve participants. Thus, usability trumps learnability. In addition, the communication systems that evolve in larger populations exhibit distinct advantages over those that evolve in smaller populations: the learnability loss (from the Initial signs) is more muted and the usability benefits are more pronounced. The usability benefits for human communication systems that evolve in a small and large population is explained through guided variation reducing sign complexity. The enhanced performance of the communication systems that evolve in larger populations is explained by the operation of a content bias acting on the larger pool of competing signs. The content bias selects for information-efficient iconic signs that aid learnability and enhance usability.

  13. Preferred habitat and effective population size drive landscape genetic patterns in an endangered species

    PubMed Central

    Weckworth, Byron V.; Musiani, Marco; DeCesare, Nicholas J.; McDevitt, Allan D.; Hebblewhite, Mark; Mariani, Stefano

    2013-01-01

    Landscape genetics provides a framework for pinpointing environmental features that determine the important exchange of migrants among populations. These studies usually test the significance of environmental variables on gene flow, yet ignore one fundamental driver of genetic variation in small populations, effective population size, Ne. We combined both approaches in evaluating genetic connectivity of a threatened ungulate, woodland caribou. We used least-cost paths to calculate matrices of resistance distance for landscape variables (preferred habitat, anthropogenic features and predation risk) and population-pairwise harmonic means of Ne, and correlated them with genetic distances, FST and Dc. Results showed that spatial configuration of preferred habitat and Ne were the two best predictors of genetic relationships. Additionally, controlling for the effect of Ne increased the strength of correlations of environmental variables with genetic distance, highlighting the significant underlying effect of Ne in modulating genetic drift and perceived spatial connectivity. We therefore have provided empirical support to emphasize preventing increased habitat loss and promoting population growth to ensure metapopulation viability. PMID:24004939

  14. From intracellular signaling to population oscillations: bridging size- and time-scales in collective behavior

    PubMed Central

    Sgro, Allyson E; Schwab, David J; Noorbakhsh, Javad; Mestler, Troy; Mehta, Pankaj; Gregor, Thomas

    2015-01-01

    Collective behavior in cellular populations is coordinated by biochemical signaling networks within individual cells. Connecting the dynamics of these intracellular networks to the population phenomena they control poses a considerable challenge because of network complexity and our limited knowledge of kinetic parameters. However, from physical systems, we know that behavioral changes in the individual constituents of a collectively behaving system occur in a limited number of well-defined classes, and these can be described using simple models. Here, we apply such an approach to the emergence of collective oscillations in cellular populations of the social amoeba Dictyostelium discoideum. Through direct tests of our model with quantitative in vivo measurements of single-cell and population signaling dynamics, we show how a simple model can effectively describe a complex molecular signaling network at multiple size and temporal scales. The model predicts novel noise-driven single-cell and population-level signaling phenomena that we then experimentally observe. Our results suggest that like physical systems, collective behavior in biology may be universal and described using simple mathematical models. PMID:25617347

  15. Differing mechanisms underlie sexual size-dimorphism in two populations of a sex-changing fish.

    PubMed

    McCormick, Mark I; Ryen, Christopher A; Munday, Philip L; Walker, Stefan P W

    2010-05-12

    Variability in the density of groups within a patchy environment lead to differences in interaction rates, growth dynamics and social organization. In protogynous hermaphrodites there are hypothesised trade-offs among sex-specific growth, reproductive output and mortality. When differences in density lead to changes to social organization the link between growth and the timing of sex-change is predicted to change. The present study explores this prediction by comparing the social organisation and sex-specific growth of two populations of a protogynous tropical wrasse, Halichoeres miniatus, which differ in density. At a low density population a strict harem structure was found, where males maintained a tight monopoly of access and spawning rights to females. In contrast, at a high density population a loosely organised system prevailed, where females could move throughout multiple male territories. Otolith microstructure revealed the species to be annual and deposit an otolith check associated with sex-change. Growth trajectories suggested that individuals that later became males in both populations underwent a growth acceleration at sex-change. Moreover, in the high density population, individuals that later became males were those individuals that had the largest otolith size at hatching and consistently deposited larger increments throughout early larval, juvenile and female life. This study demonstrates that previous growth history and growth rate changes associated with sex change can be responsible for the sexual dimorphism typically found in sex-changing species, and that the relative importance of these may be socially constrained.

  16. Using Wolbachia Releases to Estimate Aedes aegypti (Diptera: Culicidae) Population Size and Survival.

    PubMed

    Garcia, Gabriela de Azambuja; Dos Santos, Lilha Maria Barbosa; Villela, Daniel Antunes Maciel; Maciel-de-Freitas, Rafael

    2016-01-01

    Mosquitoes carrying the endosymbiont bacterium Wolbachia have been deployed in field trials as a biological control intervention due to Wolbachia effects on reducing transmission of arboviruses. We performed mark, release and recapture (MRR) experiments using Wolbachia as an internal marker with daily collections with BG-Traps during the first two weeks of releases in Rio de Janeiro, Brazil. The MRR design allowed us to investigate two critical parameters that determine whether Wolbachia would successful invade a field population: the probability of daily survival (PDS) of Wolbachia-infected Aedes aegypti females, and the wild population density during releases. Released females had a PDS of 0.82 and 0.89 in the first and second weeks, respectively, immediately after releases, which is well within the range of previous estimates of survivorship of wild mosquitoes in Rio de Janeiro. Abundance estimation of wild population varied up to 10-fold higher depending on the estimation method used (634-3565 females on the average-difference model to 6365-16188 females according to Lincoln-Petersen). Wolbachia-released mosquitoes were lower than the density estimation of their wild counterparts, irrespectively of the model used. Individually screening mosquitoes for the presence of Wolbachia reduced uncertainty on abundance estimations due to fluctuation in capturing per week. A successful invasion into local population requires Ae. aegypti fitness is unaffected by Wolbachia presence, but also reliable estimates on the population size of wild mosquitoes. PMID:27479050

  17. Comparison of facial morphologies between adult Chinese and Houstonian Caucasian populations using three-dimensional imaging.

    PubMed

    Wirthlin, J; Kau, C H; English, J D; Pan, F; Zhou, H

    2013-09-01

    The objective of this study was to compare the facial morphologies of an adult Chinese population to a Houstonian white population. Three-dimensional (3D) images were acquired via a commercially available stereophotogrammetric camera system, 3dMDface™. Using the system, 100 subjects from a Houstonian population and 71 subjects from a Chinese population were photographed. A complex mathematical algorithm was performed to generate a composite facial average (one for males and one for females) for each subgroup. The computer-generated facial averages were then superimposed based on a previously validated superimposition method. The facial averages were evaluated for differences. Distinct facial differences were evident between the subgroups evaluated. These areas included the nasal tip, the peri-orbital area, the malar process, the labial region, the forehead, and the chin. Overall, the mean facial difference between the Chinese and Houstonian female averages was 2.73±2.20mm, while the difference between the Chinese and Houstonian males was 2.83±2.20mm. The percent similarity for the female population pairings and male population pairings were 10.45% and 12.13%, respectively. The average adult Chinese and Houstonian faces possess distinct differences. Different populations and ethnicities have different facial features and averages that should be considered in the planning of treatment.

  18. Temporal sampling helps unravel the genetic structure of naturally occurring populations of a phytoparasitic nematode. 1. Insights from the estimation of effective population sizes.

    PubMed

    Jan, Pierre-Loup; Gracianne, Cécile; Fournet, Sylvain; Olivier, Eric; Arnaud, Jean-François; Porte, Catherine; Bardou-Valette, Sylvie; Denis, Marie-Christine; Petit, Eric J

    2016-03-01

    The sustainability of modern agriculture relies on strategies that can control the ability of pathogens to overcome chemicals or genetic resistances through natural selection. This evolutionary potential, which depends partly on effective population size (N e ), is greatly influenced by human activities. In this context, wild pathogen populations can provide valuable information for assessing the long-term risk associated with crop pests. In this study, we estimated the effective population size of the beet cyst nematode, Heterodera schachtii, by sampling 34 populations infecting the sea beet Beta vulgaris spp. maritima twice within a one-year period. Only 20 populations produced enough generations to analyze the variation in allele frequencies, with the remaining populations showing a high mortality rate of the host plant after only 1 year. The 20 analyzed populations showed surprisingly low effective population sizes, with most having N e close to 85 individuals. We attribute these low values to the variation in population size through time, systematic inbreeding, and unbalanced sex-ratios. Our results suggest that H. schachtii has low evolutionary potential in natural environments. Pest control strategies in which populations on crops mimic wild populations may help prevent parasite adaptation to host resistance.