Sample records for haloxylon salicornicum populations

  1. Potential of native shrubs Haloxylon salicornicum and Calligonum Polygonoides for restoration of degraded lands in Arid Western Rajasthan, India.

    PubMed

    Rathore, V S; Singh, J P; Bhardwaj, S; Nathawat, N S; Kumar, Mahesh; Roy, M M

    2015-01-01

    Shrub-induced soil property spatial heterogeneity is common in arid and semi-arid ecosystems and aids desertified land restoration. However, the effectiveness of this technique may rely on the plant species used and the habitat conditions present. To assess the degree to which planting two native species, Haloxylon salicornicum and Calligonum polygonoides, facilitates degraded land restoration, soil and herbaceous plant community properties were measured 7 years after planting. Soil samples were extracted at two depths (0-5 and 5-20 cm) from three sub-habitats, i.e., under the shrub canopy, from alleys between shrubs and from the open area. Shrub planting increased the quantity of silt + clay content (30-39 %); enhanced water holding capacities (24-30 %); increased the levels of organic carbon (48-69 %), available nitrogen (31-47 %), available phosphorus (32-41 %), and electrical conductivity (21-33 %); and decreased the pH (7-12 %) and bulk density levels (5-6 %) in the surface layer of soils beneath the canopy. Soil property changes were more significant at the surface (0-5 cm) than in the deeper layer (5-20 cm), and were more pronounced under H. salicornicum than under C. polygonoides. Furthermore, the density and biomass levels of herbaceous plants were 1.1 to 1.2 and 1.4 to 1.6 times greater, respectively, in the shrub alleys than in open area. H. salicornicum induced more robust soil amelioration and herbaceous plant facilitative properties than did C. polygonoides. Artificially planting these shrubs may thus be employed to restore degraded areas of arid regions.

  2. Strategies for adaptation of Suaeda physophora, Haloxylon ammodendron and Haloxylon persicum to a saline environment during seed-germination stage.

    PubMed

    Song, Jie; Feng, Gu; Tian, Changyan; Zhang, Fusuo

    2005-09-01

    Germination is very important for plant establishment in arid regions. The strategies taken by halophytes during the seed germination stage to adapt to saline environments in an arid zone were investigated in Suaeda physophora (euhalophyte), Haloxylon ammodendron (xero-halophyte) and Haloxylon persicum (xerophyte). Seeds of S. physophora, H. ammodendron and H. persicum were exposed to a range of iso-osmotic NaCl and PEG solutions. Seed germination in, and recovery germination from, high NaCl were recorded. The effects of iso-osmotic NaCl and PEG on seed water uptake and changes in ion content were measured. In addition, the structure of seeds and Na+ distribution in the seed coat and embryos of dry seeds were investigated. The relative increase in fresh weight of germinating seeds was markedly reduced in -2.24 MPa PEG compared with that in -2.24 MPa NaCl, while the opposite trend was found in concentration of K+ during the initial 9 h for all species. Haloxylon ammodendron and S. physophora had a higher recovery germination from -3.13 MPa NaCl compared with H. persicum. Seeds of all species had no endosperm. More Na+ was compartmentalized in the seed coats of the two halophytic species compared with that in the xerophyte H. persicum. The effect of NaCl on seed germination was due to both osmotic stress and ion toxicity for the three species. High soil salinity and a high content of Na+ in seeds may induce more seeds to remain ungerminated in S. physophora and H. ammodendron. Morphological structure and adaptation to salinity during seed germination may determine the geographical distribution of H. ammodendron and S. physophora in certain saline regions.

  3. The genus Paraplonobia Wainstein and Neopetrobia Wainstein (Acari, Trombidiformes, Tetranychidae) from Saudi Arabia: new species, new records and key to the world species of Paraplonobia.

    PubMed

    Kamran, Muhammad; Mirza, Jawwad Hassan; Alatawi, Fahad Jaber

    2016-01-01

    The two tetranychid genera Paraplonobia Wainstein and Neopetrobia Wainstein (Trombidiformes: Tetranychidae) are reported for the first time from Saudi Arabia. Three new species Paraplonobia (Anaplonobia) arabica Mirza & Alatawi, sp. n., Paraplonobia (Anaplonobia) haloxylonia Alatawi & Mirza, sp. n. and Paraplonobia (Anaplonobia) tabukensis Kamran & Alatawi, sp. n. are described and illustrated based on adult females, collected from Prosopis juliflora (SW.) Dc. (Fabaceae) and Haloxylon salicornicum Bunge (Amaranthaceae) from two different regions of Saudi Arabia. Neopetrobia mcgregori (Pritchard and Baker) is redescribed and illustrated based on female collected from Cynodon dactylon L. (Poaceae).The diagnostic morphological features including leg chaetotaxy of all known species of the subgenus Anaplonobia is tabulated. A key to the world species of the genus Paraplonobia is also provided.

  4. The genus Paraplonobia Wainstein and Neopetrobia Wainstein (Acari, Trombidiformes, Tetranychidae) from Saudi Arabia: new species, new records and key to the world species of Paraplonobia

    PubMed Central

    Kamran, Muhammad; Mirza, Jawwad Hassan; Alatawi, Fahad Jaber

    2016-01-01

    Abstract The two tetranychid genera Paraplonobia Wainstein and Neopetrobia Wainstein (Trombidiformes: Tetranychidae) are reported for the first time from Saudi Arabia. Three new species Paraplonobia (Anaplonobia) arabica Mirza & Alatawi, sp. n., Paraplonobia (Anaplonobia) haloxylonia Alatawi & Mirza, sp. n. and Paraplonobia (Anaplonobia) tabukensis Kamran & Alatawi, sp. n. are described and illustrated based on adult females, collected from Prosopis juliflora (SW.) Dc. (Fabaceae) and Haloxylon salicornicum Bunge (Amaranthaceae) from two different regions of Saudi Arabia. Neopetrobia mcgregori (Pritchard and Baker) is redescribed and illustrated based on female collected from Cynodon dactylon L. (Poaceae).The diagnostic morphological features including leg chaetotaxy of all known species of the subgenus Anaplonobia is tabulated. A key to the world species of the genus Paraplonobia is also provided. PMID:27408589

  5. [Effects of different irrigations on the water physiological characteristics of Haloxylon ammodendron in Taklimakan Desert hinterland].

    PubMed

    Xie, Ting-ting; Zhang, Xi-ming; Liang, Shao-min; Shan, Li-shan; Yang, Xiao-lin; Hua, Yong-hui

    2008-04-01

    By using heat-balance stem flow gauge and press chamber, the water physiological characteristics of Haloxylon ammodendron under different irrigations in Taklimakan Desert hinterland were measured and analyzed. The results indicated that the diurnal variation curve of H. ammodendron stem sap flow varied with irrigations. When irrigated 35 and 24.5 kg x plant(-1) once time, the diurnal variation of stem sap flow changed in single peak curve and the variation extent was higher; while irrigated 14 kg x plant(-1) once time, the diurnal variation changed in two-peak curve and the variation extent was small. With the decrease of irrigations, the average daily sap flow rate and the daily water consumption of H. ammodendron decreased gradually, the dawn and postmeridian water potential also had a gradual decrease, and the correlations of stem sap flow with total radiation, air temperature, relative humidity, and wind speed enhanced. Under different irrigations, the correlation between stem sap flow rate and total radiation was always the best.

  6. Isolation of plant-growth-promoting rhizobacteria from rhizospheric soil of halophytes and their impact on maize (Zea mays L.) under induced soil salinity.

    PubMed

    Ullah, Sami; Bano, Asghari

    2015-04-01

    The present investigation was aimed to scrutinize the salt tolerance potential of plant-growth-promoting rhizobacteria (PGPR) isolated from rhizospheric soil of selected halophytes (Atriplex leucoclada, Haloxylon salicornicum, Lespedeza bicolor, Suaeda fruticosa, and Salicornica virginica) collected from high-saline fields (electrical conductivity 4.3-5.5) of District Mardan, Pakistan. Five PGPR strains were identified using 16S rRNA amplification and sequence analysis. Bacillus sp., isolated from rhizospheric soil of Atriplex leucoclada, and Arthrobacter pascens, isolated from rhizospheric soil of Suaeda fruticosa, are active phosphate solubilizers and bacteriocin and siderophore producers; hence, their inoculation and co-inoculation on maize ('Rakaposhi') under induced salinity stress enhanced shoot and root length and shoot and root fresh and dry mass. The accumulation of osmolytes, including sugar and proline, and the elevation of antioxidant enzymes activity, including superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase, were enhanced in the maize variety when inoculated and co-inoculated with Bacillus sp. and Arthrobacter pascens. The PGPR (Bacillus sp. and A. pascens) isolated from the rhizosphere of the mentioned halophytes species showed reliability in growth promotion of maize crop in all the physiological parameters; hence, they can be used as bio-inoculants for the plants growing under salt stress.

  7. Impacts of water and nitrogen addition on nitrogen recovery in Haloxylon ammodendron dominated desert ecosystems.

    PubMed

    Cui, Xiaoqing; Yue, Ping; Gong, Yanming; Li, Kaihui; Tan, Dunyan; Goulding, Keith; Liu, Xuejun

    2017-12-01

    Desert ecosystems are likely to change in response to global climate change and nitrogen (N) deposition. The effects of increased precipitation and N deposition on plant growth and the N cycle largely depend on N allocation and N recovery efficiency in the plant-soil ecosystem, but there is limited research on this in desert ecosystems. Here we report results using double-labeled 15 NH 4 15 NO 3 (30 and 60kgNha -1 yr -1 ) as a tracer under ambient (no additional water addition) and enhanced precipitation (60mm water addition) in a Haloxylon ammodendron dominated ecosystem in the Gurbantunggut Desert of Northwest China. Herbaceous plants were a significantly larger sink for added 15 N than the H. ammodendron trees, and N retention varied with water and N addition, relative to growing season precipitation. The retention of added 15 N varied within the components of H. ammodendron, with the stems retaining most, followed by the assimilation branches. Soil was the dominant sink for added 15 N, in which the topsoil and subsoil respond differently to water and N addition over the two-year period. Nitrogen relative recovery percentage in the whole ecosystem ranged from 43% to 61%, lower than average recovery rate in temperate forests; N tracer recovery percentage significantly increased with water addition but decreased with enhanced N deposition. Future N cycling in central Asian deserts will depend on changes in precipitation. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Effects of increasing root carbon investment on the mortality and resprouting of Haloxylon ammodendron seedlings under drought.

    PubMed

    Zhang, Y; Xie, J-B; Li, Y

    2017-03-01

    Tree mortality induced by drought is one of the most complex processes in ecology. Although two mechanisms associated with water and carbon balance are proposed to explain tree mortality, outstanding problems still exist. Here, in order to test how the root system benefits survival and resprouting of Haloxylon ammodendron seedlings, we examined the various water- and carbon-related physiological indicators (shoot water potential, photosynthesis, dark respiration, hydraulic conductance and non-structural carbohydrates [NSC]) of H. ammodendron seedlings, which were grown in drought and control conditions throughout a grow season in greenhouse. The survival time of the seedling root system (died 70 days after drought) doubled the survival time of the shoot (died at 35 days). Difference in survival time between shoot and root resulted from sustained root respiration supported by increased NSC in roots under drought. Furthermore, investment into the root contributed to resprouting following drought. Based on these results, a death criterion is proposed for this species. The time sequence of major events indicated that drought shifted carbon allocation between shoot and root and altered the flux among different sinks (growth, respiration or storage). The interaction of water and carbon processes determined death or survival of droughted H. ammodendron seedlings. These findings revealed that the 'root protection' strategy is critical in determining survival and resprouting of this species, and provided insights into the effects of carbon and water dynamics on tree mortality. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

  9. Interactive response of photosynthetic characteristics in Haloxylon ammodendron and Hedysarum scoparium exposed to soil water and air vapor pressure deficits.

    PubMed

    Gong, Chunmei; Wang, Jiajia; Hu, Congxia; Wang, Junhui; Ning, Pengbo; Bai, Juan

    2015-08-01

    C4 plants possess better drought tolerance than C3 plants. However, Hedysarum scoparium, a C3 species, is dominant and widely distributed in the desert areas of northwestern China due to its strong drought tolerance. This study compared it with Haloxylon ammodendron, a C4 species, regarding the interactive effects of drought stress and different leaf-air vapor pressure deficits. Variables of interest included gas exchange, the activity levels of key C4 photosynthetic enzymes, and cellular anatomy. In both species, gas exchange parameters were more sensitive to high vapor pressure deficit than to strong water stress, and the net CO2 assimilation rate (An) was enhanced as vapor pressure deficits increased. A close relationship between An and stomatal conductance (gs) suggested that the species shared a similar response mechanism. In H. ammodendron, the activity levels of key C4 enzymes were higher, including those of phosphoenolpyruvate carboxylase (PEPC) and nicotinamide adenine dinucleotide phosphate-malate enzyme (NADP-ME), whereas in H. scoparium, the activity level of nicotinamide adenine dinucleotide-malate enzyme (NAD-ME) was higher. Meanwhile, H. scoparium utilized adaptive structural features, including a larger relative vessel area and a shorter distance from vein to stomata, which facilitated the movement of water. These findings implied that some C4 biochemical pathways were present in H. scoparium to respond to environmental challenges. Copyright © 2015. Published by Elsevier B.V.

  10. [Characteristics of main layer and regeneration layer of Haloxylon ammodendron plantations at different ages on the southern edge of the Gurbantunggut Desert, Northwest China].

    PubMed

    Chen, Qi Min; Luo, Qing Hong; Ning, Hu Sen; Zhao, Cheng Yi; Duan, Wen Biao

    2017-03-18

    The population structure characteristics, natural regeneration, and the influential factors of Haloxylon ammodendron plantations at six different stand ages on the southern edge of the Gurbantunggut Desert were studied. The results showed that H. ammodendron plantation at the stand age of 7 could naturally regenerate. At the stand age of 17, the densities of the seedlings (<30 cm height), saplings (30≤H<50 height), and small trees (≥50 cm height) reached optimal class, and the mean height and base diameter of the small tress reached 1.10 m and 1.91 cm, respectively. The parent trees in H. ammodendron plantation at the stand age of 20 grew best. The height of 35% individuals grew up to 2.50-3.00 m, and the basal stem diameter of 23.1% individuals grew up to 8.00-10.00 cm. The height and diameter growth of the parent trees in H. ammodendron plantation at the stand age of 33 apparently declined, but the regeneration ability by natural seed dispersal was still strong. The regeneration density of natural seed dispersal showed the greatest correlation with the available nitrogen content in 0-100 cm soil layer (0.87), followed by the soil rapidly available phosphorus content (0.84) and the soil water content (0.79). The soils with pH 8.1-8.6 did not limit the nutrient growth of the regeneration layer. In the main stand layer, the individual density of whole regeneration layer showed the greatest correlation with the biomass of the parent trees (0.77), while the density of regeneration layer of the small trees showed the greatest correlation with the planting density (0.71) and the age of the parent trees (0.70).

  11. Long-Term Effects of Xerophytic Shrub Haloxylon ammodendron Plantations on Soil Properties and Vegetation Dynamics in Northwest China

    PubMed Central

    Fan, Baoli; Zhang, Aiping; Yang, Yi; Ma, Quanlin; Li, Xuemin; Zhao, Changming

    2016-01-01

    The xerophytic desert shrub Haloxylon ammodendron (C. A. Mey.) Bunge. is distributed naturally in Asian and African deserts, and is widely used for vegetation restoration in the desert regions of Northern China. However, there are limited long-term chrono-sequence studies on the impact of changed soil properties and vegetation dynamics following establishment of this shrub on mobile sand dunes. In Minqin County, Gansu Province, we investigated soil properties and herbaceous vegetation development of 10, 20, 30, 40, 50-year-old H. ammodendron plantations on mobile sand dunes. Soil sampling at two depths (0–5 and 5–20 cm) under the shrubs determined SOC, nutrition and soil physical characteristics. The results showed that: establishment of H. ammodendron had improved soil physio-chemical properties, increased thickness of soil crusts and coverage of biological soil crusts (BSCs), and promoted development of topsoil over an extended period of 5 decades. Soil texture and soil nutrition improved along the chrono-sequence according to three distinct phases: i) an initial fast development from 0 to 10 years, ii) a stabilizing phase from 10 to 30 years followed by iii) a relatively marked restoration development in 40 and 50-year-old plantations. Meanwhile, herbaceous community coverage also markedly increased in 30-year-old plantations. However, both soil and vegetation restoration were very slow due to low annual precipitation in Minqin county compared to other Northern China sand afforestation sites. Canonical Correspondence Analysis results demonstrated that herbaceous plant development was closely associated with changes in soil texture (increased clay and silt percentage) and availability of soil nutrients. Thus our results indicated that selection of the long-lived shrub H. ammodendron is an essential and effective tool in arid desert re-vegetation. PMID:27992458

  12. [Effects of environmental factors on evapotranspiration characteristics of Haloxylon ammodendron plantation in the Minqin oasis-desert ectone, Northwest China.

    PubMed

    Zhang, Xiao Yan; Chu, Jian Min; Meng, Ping; Zheng, Ning; Yao, Zeng Wang; Wang, He Song; Jiang, Sheng Xiu

    2016-08-01

    This study continuously measured the evapotranspiration (ET) of degraded Haloxylon ammodendron shrub plantation of Minqin oasis-desert ectone using an eddy covariance system for ET, and TDR for soil moisture profile, analyzing ET in relation to the weather conditions and describing the responses of ET to the microclimate variables in different weather from July 2014 to June 2015. Results showed that the hourly ET dynamics had an apparent seasonal trend in the growing season. This trend gradually increased in the beginning of season from the low level of non-growing season, reached its maximum peak value (0.07 mm·h -1 ) in the most physiologically active period, and decreased to the minimum peak value (0.01 mm·h -1 ) in December. The diurnal change in ET of the plantation depended on the weather conditions. The ET fluctuated less with a small magnitude in a cloud day, but fluctuated obviously with a greater magnitude after rain if weather was clear. After a strong rainfall (>9 mm·d -1 ), ET increased sharply to a high level of 28 folds prior to rain, at which it took four clear days to gradually decease to the pre-rain ET level. The yearly ET over H. ammodendron plantation was 108 mm, equivalent to 98% of annual precipitation. Soil moisture was the water source for ET. Therefore, soil moisture was the dominant factor for theET over the plantation. Net radiation, photosynthesis active radiation, air temperature, and vapor pressure deficit were the microclimate variables to drive the transpiration of vegetation and evaporation over the soil surface, being the major factors forET over the plantation. The regression equation of ET to the dominant factor and major factors had a coefficient of multiple determination (R 2 ) over 0.80.

  13. Complete Chloroplast Genome Sequence of Holoparasite Cistanche deserticola (Orobanchaceae) Reveals Gene Loss and Horizontal Gene Transfer from Its Host Haloxylon ammodendron (Chenopodiaceae)

    PubMed Central

    Qiao, Qin; Ren, Zhumei; Zhao, Jiayuan; Yonezawa, Takahiro; Hasegawa, Masami; Crabbe, M. James C; Li, Jianqiang; Zhong, Yang

    2013-01-01

    Background The central function of chloroplasts is to carry out photosynthesis, and its gene content and structure are highly conserved across land plants. Parasitic plants, which have reduced photosynthetic ability, suffer gene losses from the chloroplast (cp) genome accompanied by the relaxation of selective constraints. Compared with the rapid rise in the number of cp genome sequences of photosynthetic organisms, there are limited data sets from parasitic plants. Principal Findings/Significance Here we report the complete sequence of the cp genome of Cistanche deserticola, a holoparasitic desert species belonging to the family Orobanchaceae. The cp genome of C. deserticola is greatly reduced both in size (102,657 bp) and in gene content, indicating that all genes required for photosynthesis suffer from gene loss and pseudogenization, except for psbM. The striking difference from other holoparasitic plants is that it retains almost a full set of tRNA genes, and it has lower dN/dS for most genes than another close holoparasitic plant, E. virginiana, suggesting that Cistanche deserticola has undergone fewer losses, either due to a reduced level of holoparasitism, or to a recent switch to this life history. We also found that the rpoC2 gene was present in two copies within C. deserticola. Its own copy has much shortened and turned out to be a pseudogene. Another copy, which was not located in its cp genome, was a homolog of the host plant, Haloxylon ammodendron (Chenopodiaceae), suggesting that it was acquired from its host via a horizontal gene transfer. PMID:23554920

  14. Complete chloroplast genome sequence of holoparasite Cistanche deserticola (Orobanchaceae) reveals gene loss and horizontal gene transfer from its host Haloxylon ammodendron (Chenopodiaceae).

    PubMed

    Li, Xi; Zhang, Ti-Cao; Qiao, Qin; Ren, Zhumei; Zhao, Jiayuan; Yonezawa, Takahiro; Hasegawa, Masami; Crabbe, M James C; Li, Jianqiang; Zhong, Yang

    2013-01-01

    The central function of chloroplasts is to carry out photosynthesis, and its gene content and structure are highly conserved across land plants. Parasitic plants, which have reduced photosynthetic ability, suffer gene losses from the chloroplast (cp) genome accompanied by the relaxation of selective constraints. Compared with the rapid rise in the number of cp genome sequences of photosynthetic organisms, there are limited data sets from parasitic plants. PRINCIPAL FINDINGS/SIGNIFICANCE: Here we report the complete sequence of the cp genome of Cistanche deserticola, a holoparasitic desert species belonging to the family Orobanchaceae. The cp genome of C. deserticola is greatly reduced both in size (102,657 bp) and in gene content, indicating that all genes required for photosynthesis suffer from gene loss and pseudogenization, except for psbM. The striking difference from other holoparasitic plants is that it retains almost a full set of tRNA genes, and it has lower dN/dS for most genes than another close holoparasitic plant, E. virginiana, suggesting that Cistanche deserticola has undergone fewer losses, either due to a reduced level of holoparasitism, or to a recent switch to this life history. We also found that the rpoC2 gene was present in two copies within C. deserticola. Its own copy has much shortened and turned out to be a pseudogene. Another copy, which was not located in its cp genome, was a homolog of the host plant, Haloxylon ammodendron (Chenopodiaceae), suggesting that it was acquired from its host via a horizontal gene transfer.

  15. Nonlinear spectral mixture effects for photosynthetic/non-photosynthetic vegetation cover estimates of typical desert vegetation in western China.

    PubMed

    Ji, Cuicui; Jia, Yonghong; Gao, Zhihai; Wei, Huaidong; Li, Xiaosong

    2017-01-01

    Desert vegetation plays significant roles in securing the ecological integrity of oasis ecosystems in western China. Timely monitoring of photosynthetic/non-photosynthetic desert vegetation cover is necessary to guide management practices on land desertification and research into the mechanisms driving vegetation recession. In this study, nonlinear spectral mixture effects for photosynthetic/non-photosynthetic vegetation cover estimates are investigated through comparing the performance of linear and nonlinear spectral mixture models with different endmembers applied to field spectral measurements of two types of typical desert vegetation, namely, Nitraria shrubs and Haloxylon. The main results were as follows. (1) The correct selection of endmembers is important for improving the accuracy of vegetation cover estimates, and in particular, shadow endmembers cannot be neglected. (2) For both the Nitraria shrubs and Haloxylon, the Kernel-based Nonlinear Spectral Mixture Model (KNSMM) with nonlinear parameters was the best unmixing model. In consideration of the computational complexity and accuracy requirements, the Linear Spectral Mixture Model (LSMM) could be adopted for Nitraria shrubs plots, but this will result in significant errors for the Haloxylon plots since the nonlinear spectral mixture effects were more obvious for this vegetation type. (3) The vegetation canopy structure (planophile or erectophile) determines the strength of the nonlinear spectral mixture effects. Therefore, no matter for Nitraria shrubs or Haloxylon, the non-linear spectral mixing effects between the photosynthetic / non-photosynthetic vegetation and the bare soil do exist, and its strength is dependent on the three-dimensional structure of the vegetation canopy. The choice of linear or nonlinear spectral mixture models is up to the consideration of computational complexity and the accuracy requirement.

  16. Nonlinear spectral mixture effects for photosynthetic/non-photosynthetic vegetation cover estimates of typical desert vegetation in western China

    PubMed Central

    Jia, Yonghong; Gao, Zhihai; Wei, Huaidong

    2017-01-01

    Desert vegetation plays significant roles in securing the ecological integrity of oasis ecosystems in western China. Timely monitoring of photosynthetic/non-photosynthetic desert vegetation cover is necessary to guide management practices on land desertification and research into the mechanisms driving vegetation recession. In this study, nonlinear spectral mixture effects for photosynthetic/non-photosynthetic vegetation cover estimates are investigated through comparing the performance of linear and nonlinear spectral mixture models with different endmembers applied to field spectral measurements of two types of typical desert vegetation, namely, Nitraria shrubs and Haloxylon. The main results were as follows. (1) The correct selection of endmembers is important for improving the accuracy of vegetation cover estimates, and in particular, shadow endmembers cannot be neglected. (2) For both the Nitraria shrubs and Haloxylon, the Kernel-based Nonlinear Spectral Mixture Model (KNSMM) with nonlinear parameters was the best unmixing model. In consideration of the computational complexity and accuracy requirements, the Linear Spectral Mixture Model (LSMM) could be adopted for Nitraria shrubs plots, but this will result in significant errors for the Haloxylon plots since the nonlinear spectral mixture effects were more obvious for this vegetation type. (3) The vegetation canopy structure (planophile or erectophile) determines the strength of the nonlinear spectral mixture effects. Therefore, no matter for Nitraria shrubs or Haloxylon, the non-linear spectral mixing effects between the photosynthetic / non-photosynthetic vegetation and the bare soil do exist, and its strength is dependent on the three-dimensional structure of the vegetation canopy. The choice of linear or nonlinear spectral mixture models is up to the consideration of computational complexity and the accuracy requirement. PMID:29240777

  17. Genetic diversity and environmental associations of sacsaoul ( Haloxylon ammodendron)

    NASA Astrophysics Data System (ADS)

    Zhang, Linjing; Zhao, Guifang; Yue, Ming; Pan, Xiaoling

    2003-07-01

    Random amplified polymorphic DNA (RAPD) markers were used to assess levels and patterns of genetic diversity in H. ammodendron (Chenopodiaceae). A total of 117 plants from 6 subpopulations on oasis-desert ecotone was analyzed by 16 arbitrarily chosen primers resulting in highly reproducible RAPD bands. The analysis of molecular variance (AMOVA) with distances among individuals showed that most of the variation (74%) occurred among individuals within subpopulations, which is expected for a crossing organism, and 26% of variation among subpopulations. Estimates of Shannon index and Nei"s index from allele frequencies corroborated AMOVA partitioning in H. ammodendron. UPGMA cluster analyses, based on genetic distance, do not revealed grouping of some geographically proximate populations. This is the first report of the partitioning of genetic variability within and between subpopulations of H. ammodendron and provides important baseline data for optimizing sampling strategies and for conserving the genetic resources of this species. The Percentage of polymorphic loci was as high as 96%, presumably being response to oasis-desert ecotone. There were gene flows (Nm=5.38 individuals/generation), based on gene differentiation coefficient (GST was 0.1567) between subpopulations, and strong habitat selection override the gene flow to maintain the subpopulation differentiation. Correlation analyses showed that there was significant relationship between genetic diversity and soil CL ion.

  18. Is a Clean Development Mechanism project economically justified? Case study of an International Carbon Sequestration Project in Iran.

    PubMed

    Katircioglu, Salih; Dalir, Sara; Olya, Hossein G

    2016-01-01

    The present study evaluates a carbon sequestration project for the three plant species in arid and semiarid regions of Iran. Results show that Haloxylon performed appropriately in the carbon sequestration process during the 6 years of the International Carbon Sequestration Project (ICSP). In addition to a high degree of carbon dioxide sequestration, Haloxylon shows high compatibility with severe environmental conditions and low maintenance costs. Financial and economic analysis demonstrated that the ICSP was justified from an economic perspective. The financial assessment showed that net present value (NPV) (US$1,098,022.70), internal rate of return (IRR) (21.53%), and payback period (6 years) were in an acceptable range. The results of the economic analysis suggested an NPV of US$4,407,805.15 and an IRR of 50.63%. Therefore, results of this study suggest that there are sufficient incentives for investors to participate in such kind of Clean Development Mechanism (CDM) projects.

  19. Nutritive value of some herbages for dromedary camel in Iran.

    PubMed

    Towhidi, A

    2007-01-01

    To prepare standard tables of chemical composition of feedstuffs and to determine digestibility and palatability of different plant species in dromedary camel, this research was carried out by considering the most consuming herbages of Iranian desert rages. The plant species were included Atriplex lentiformis, Alhagi persarum, Seidlitzia rosmarinus, Saueda fruticosa, Haloxylon ammodendron, Tamarix kotschyi, Hammada salicornica, Salsola yazdiana, Salsola tomentosa, Tamarix aphylla and Artemisia sieberi. Thirty samples of the browsing parts were collected from the rangelands of Yazd province in autumn. Chemical composition of samples including Dry Matter (DM), Crude Protein (CP), Crude Fiber (CF), Neutral Detergent Fiber (NDF), Acid Detergent Fiber (ADF), Ether Extract (EE), Total Ash (TA), macro elements (Ca, P, Mg, K), micro elements (Fe, Mg, Cu, Zn)and gross energy (GE) were analyzed. The in vitro digestibility was determined by camel rumen liquor in Tilley and Terry method. Palatability of the plants were measured by three mature camels in cafeteria trials. The camels voluntarily fed 11 plant species during one hour for six days. Data were analyzed by GLM method in SAS software. The highest CP (18.3%) and the lowest NDF (40.4%) and ADF (35.4%) were related to Tamarix aphylla. The lowest CP (5.5%) and the highest NDF (72.8%) and ADF (59.6%) were related to Artemisia sieberi. The highest organic matter digestibility in dry matter was related to Haloxylon ammodendron. The results also indicated that Atriplex lentiformis, Alhagi persarum, Seidlitzia rosmarinus, Saueda fruticosa, Haloxylon ammodendron, Salsola tomentosa, Hammada salicornica, Tamarix kotschyi, Salsola yazdiana, Tamarix aphylla and Artemisia sieberi were more pleasure feed, respectively. It was not observed any correlation between %DOMD and chemical composition. Moreover, There was not a consistent relationship between the palatability of herbages with %DOMD or chemical composition.

  20. Apparent plasticity in functional traits determining competitive ability and spatial distribution: a case from desert.

    PubMed

    Xie, Jiang-Bo; Xu, Gui-Qing; Jenerette, G Darrel; Bai, Yong-fei; Wang, Zhong-Yuan; Li, Yan

    2015-07-20

    Species competitive abilities and their distributions are closely related to functional traits such as biomass allocation patterns. When we consider how nutrient supply affects competitive abilities, quantifying the apparent and true plasticity in functional traits is important because the allometric relationships among traits are universal in plants. We propose to integrate the notion of allometry and the classical reaction norm into a composite theoretical framework that quantifies the apparent and true plasticity. Combining the framework with a meta-analysis, a series of field surveys and a competition experiment, we aimed to determine the causes of the dune/interdune distribution patterns of two Haloxylon species in the Gurbantonggut Desert. We found that (1) the biomass allocation patterns of both Haloxylon species in responses to environmental conditions were apparent rather than true plasticity and (2) the allometric allocation patterns affected the plants' competition for soil nutrient supply. A key implication of our results is that the apparent plasticity in functional traits of plants determines their response to environmental change. Without identifying the apparent and true plasticity, we would substantially overestimate the magnitude, duration and even the direction of plant responses in functional traits to climate change.

  1. Apparent plasticity in functional traits determining competitive ability and spatial distribution: a case from desert

    PubMed Central

    Xie, Jiang-Bo; Xu, Gui-Qing; Jenerette, G. Darrel; Bai, Yong-fei; Wang, Zhong-Yuan; Li, Yan

    2015-01-01

    Species competitive abilities and their distributions are closely related to functional traits such as biomass allocation patterns. When we consider how nutrient supply affects competitive abilities, quantifying the apparent and true plasticity in functional traits is important because the allometric relationships among traits are universal in plants. We propose to integrate the notion of allometry and the classical reaction norm into a composite theoretical framework that quantifies the apparent and true plasticity. Combining the framework with a meta-analysis, a series of field surveys and a competition experiment, we aimed to determine the causes of the dune/interdune distribution patterns of two Haloxylon species in the Gurbantonggut Desert. We found that (1) the biomass allocation patterns of both Haloxylon species in responses to environmental conditions were apparent rather than true plasticity and (2) the allometric allocation patterns affected the plants’ competition for soil nutrient supply. A key implication of our results is that the apparent plasticity in functional traits of plants determines their response to environmental change. Without identifying the apparent and true plasticity, we would substantially overestimate the magnitude, duration and even the direction of plant responses in functional traits to climate change. PMID:26190745

  2. Moderate irrigation intervals facilitate establishment of two desert shrubs in the Taklimakan Desert Highway Shelterbelt in China.

    PubMed

    Li, Congjuan; Shi, Xiang; Mohamad, Osama Abdalla; Gao, Jie; Xu, Xinwen; Xie, Yijun

    2017-01-01

    Water influences various physiological and ecological processes of plants in different ecosystems, especially in desert ecosystems. The purpose of this study is to investigate the response of physiological and morphological acclimation of two shrubs Haloxylon ammodendron and Calligonum mongolicunl to variations in irrigation intervals. The irrigation frequency was set as 1-, 2-, 4-, 8- and 12-week intervals respectively from March to October during 2012-2014 to investigate the response of physiological and morphological acclimation of two desert shrubs Haloxylon ammodendron and Calligonum mongolicunl to variations in the irrigation system. The irrigation interval significantly affected the individual-scale carbon acquisition and biomass allocation pattern of both species. Under good water conditions (1- and 2-week intervals), carbon assimilation was significantly higher than other treatments; while, under water shortage conditions (8- and 12-week intervals), there was much defoliation; and under moderate irrigation intervals (4 weeks), the assimilative organs grew gently with almost no defoliation occurring. Both studied species maintained similar ecophysiologically adaptive strategies, while C. mongolicunl was more sensitive to drought stress because of its shallow root system and preferential belowground allocation of resources. A moderate irrigation interval of 4 weeks was a suitable pattern for both plants since it not only saved water but also met the water demands of the plants.

  3. Moderate irrigation intervals facilitate establishment of two desert shrubs in the Taklimakan Desert Highway Shelterbelt in China

    PubMed Central

    Li, Congjuan; Shi, Xiang; Mohamad, Osama Abdalla; Gao, Jie; Xu, Xinwen; Xie, Yijun

    2017-01-01

    Background Water influences various physiological and ecological processes of plants in different ecosystems, especially in desert ecosystems. The purpose of this study is to investigate the response of physiological and morphological acclimation of two shrubs Haloxylon ammodendron and Calligonum mongolicunl to variations in irrigation intervals. Methodology/Principal findings The irrigation frequency was set as 1-, 2-, 4-, 8- and 12-week intervals respectively from March to October during 2012–2014 to investigate the response of physiological and morphological acclimation of two desert shrubs Haloxylon ammodendron and Calligonum mongolicunl to variations in the irrigation system. The irrigation interval significantly affected the individual-scale carbon acquisition and biomass allocation pattern of both species. Under good water conditions (1- and 2-week intervals), carbon assimilation was significantly higher than other treatments; while, under water shortage conditions (8- and 12-week intervals), there was much defoliation; and under moderate irrigation intervals (4 weeks), the assimilative organs grew gently with almost no defoliation occurring. Conclusion/Significance Both studied species maintained similar ecophysiologically adaptive strategies, while C. mongolicunl was more sensitive to drought stress because of its shallow root system and preferential belowground allocation of resources. A moderate irrigation interval of 4 weeks was a suitable pattern for both plants since it not only saved water but also met the water demands of the plants. PMID:28719623

  4. Effective population size of korean populations.

    PubMed

    Park, Leeyoung

    2014-12-01

    Recently, new methods have been developed for estimating the current and recent changes in effective population sizes. Based on the methods, the effective population sizes of Korean populations were estimated using data from the Korean Association Resource (KARE) project. The overall changes in the population sizes of the total populations were similar to CHB (Han Chinese in Beijing, China) and JPT (Japanese in Tokyo, Japan) of the HapMap project. There were no differences in past changes in population sizes with a comparison between an urban area and a rural area. Age-dependent current and recent effective population sizes represent the modern history of Korean populations, including the effects of World War II, the Korean War, and urbanization. The oldest age group showed that the population growth of Koreans had already been substantial at least since the end of the 19th century.

  5. World Population: Facts in Focus. World Population Data Sheet Workbook. Population Learning Series.

    ERIC Educational Resources Information Center

    Crews, Kimberly A.

    This workbook teaches population analysis using world population statistics. To complete the four student activity sheets, the students refer to the included "1988 World Population Data Sheet" which lists nations' statistical data that includes population totals, projected population, birth and death rates, fertility levels, and the…

  6. Farm Population of the United States: 1974. Current Population Reports, Farm Population.

    ERIC Educational Resources Information Center

    Banks, Vera J.; And Others

    Based on data derived primarily from the Current Population Survey of the Bureau of the Census, this statistical report presents demographic and labor force characteristics of the U.S. farm population and a comparison of selected characteristics of the farm and nonfarm population. Tabular data are presented as follows: (1) Population of the U.S.,…

  7. Farm Population of the United States: 1971. Current Population Reports: Farm Population.

    ERIC Educational Resources Information Center

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

    Based on data derived from the Current Population Survey of the Bureau of the Census, this statistical report presents demographic and labor force characteristics of the U.S. farm population and comparisons of the farm and nonfarm populations. Tabular data are presented as follows: (1) U.S. Population, Total and Farm: April 1960 and 1971; (2)…

  8. Farm Population of the United States: 1972. Current Population Reports: Farm Population.

    ERIC Educational Resources Information Center

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

    Based on data derived from the Current Population Survey of the Bureau of Census, this statistical report presents demographic and labor force characteristics of the U.S. farm population and comparisons of the farm and nonfarm populations. Tabular data are presented as follows: (1) U.S. Population, Total and Farm: April 1960 to 1972; (2) Persons…

  9. Population control II: The population establishment today.

    PubMed

    Hartmann, B

    1997-01-01

    Although population assistance represents a relatively small share of official development assistance, it influences many other aspects of development planning. The organizations that comprise the population establishment have a common purpose--the reduction of population growth in the Third World--but they are not homogeneous and sometimes have conflicting goals and strategies. National governments, multilateral agencies, nongovernmental organizations, foundations, academic centers, and pressure groups all contribute to creating and sustaining what has become a virtual population control industry. Through scholarships, travel grants, awards, and favorable publicity, Third World elites have been encouraged to join the population establishment. The World Bank, the U.S. Agency for International Development, and the U.N. Fund for Population Activities have pursued explicit strategies for pressuring Third World governments to design and implement population policies, most recently in Africa.

  10. Global Population Profile: 2002. International Population Reports

    ERIC Educational Resources Information Center

    Christenson, Matthew; McDevitt, Thomas; Stanecki, Karen

    2004-01-01

    Global Population Profile: 2002 summarizes the most important trends in global population at the dawn of the 21st century. The presentation is organized around four themes: (1) Global Population; (2) Growth, Global Population; (3) Composition, Contraceptive Prevalence in the Developing World; and (4) the AIDS Pandemic in the 21st Century. This…

  11. Estimating finite-population reproductive numbers in heterogeneous populations.

    PubMed

    Keegan, Lindsay T; Dushoff, Jonathan

    2016-05-21

    The basic reproductive number, R0, is one of the most important epidemiological quantities. R0 provides a threshold for elimination and determines when a disease can spread or when a disease will die out. Classically, R0 is calculated assuming an infinite population of identical hosts. Previous work has shown that heterogeneity in the host mixing rate increases R0 in an infinite population. However, it has been suggested that in a finite population, heterogeneity in the mixing rate may actually decrease the finite-population reproductive numbers. Here, we outline a framework for discussing different types of heterogeneity in disease parameters, and how these affect disease spread and control. We calculate "finite-population reproductive numbers" with different types of heterogeneity, and show that in a finite population, heterogeneity has complicated effects on the reproductive number. We find that simple heterogeneity decreases the finite-population reproductive number, whereas heterogeneity in the intrinsic mixing rate (which affects both infectiousness and susceptibility) increases the finite-population reproductive number when R0 is small relative to the size of the population and decreases the finite-population reproductive number when R0 is large relative to the size of the population. Although heterogeneity has complicated effects on the finite-population reproductive numbers, its implications for control are straightforward: when R0 is large relative to the size of the population, heterogeneity decreases the finite-population reproductive numbers, making disease control or elimination easier than predicted by R0. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Farm Population of the United States: 1976. Current Population Reports: Farm Population.

    ERIC Educational Resources Information Center

    Banks, Vera J.; And Others

    Prepared cooperatively by the Bureau of the Census and the Economic Research Service of the U.S. DeparLment of Agriculture, this document presents narrative and tabular data on: demographic and social characteristics of the farm population; economic characteristics of the farm population; revision of farm population processing procedures; and…

  13. Water use patterns of co-occurring C3 and C4 shrubs in the Gurbantonggut desert in northwestern China.

    PubMed

    Tiemuerbieke, Bahejiayinaer; Min, Xiao-Jun; Zang, Yong-Xin; Xing, Peng; Ma, Jian-Ying; Sun, Wei

    2018-09-01

    In water-limited ecosystems, spatial and temporal partitioning of water sources is an important mechanism that facilitates plant survival and lessens the competition intensity of co-existing plants. Insights into species-specific root functional plasticity and differences in the water sources of co-existing plants under changing water conditions can aid in accurate prediction of the response of desert ecosystems to future climate change. We used stable isotopes of soil water, groundwater and xylem water to determine the seasonal and inter- and intraspecific differences variations in the water sources of six C 3 and C 4 shrubs in the Gurbantonggut desert. We also measured the stem water potentials to determine the water stress levels of each species under varying water conditions. The studied shrubs exhibited similar seasonal water uptake patterns, i.e., all shrubs extracted shallow soil water recharged by snowmelt water during early spring and reverted to deeper water sources during dry summer periods, indicating that all of the studied shrubs have dimorphic root systems that enable them to obtain water sources that differ in space and time. Species in the C 4 shrub community exhibited differences in seasonal water absorption and water status due to differences in topography and rooting depth, demonstrating divergent adaptations to water availability and water stress. Haloxylon ammodendron and T. ramosissima in the C 3 /C 4 mixed community were similar in terms of seasonal water extraction but differed with respect to water potential, which indicated that plant water status is controlled by both root functioning and shoot eco-physiological traits. The two Tamarix species in the C 3 shrub community were similar in terms of water uptake and water status, which suggests functional convergence of the root system and physiological performance under same soil water conditions. In different communities, Haloxylon ammodendron differed in terms of summer water extraction

  14. [Population].

    PubMed

    1979-01-01

    Data on the population of Venezuela between 1975 and 1977 are presented in descriptive tables and graphs. Information is included on the employed population according to category, sex, and type of economic activity, and by sex, age, and area on the employment rate and the total, the economically active, and the unemployed population.

  15. Farm Population of the United States: 1977. Current Population Reports: Farm Population.

    ERIC Educational Resources Information Center

    Banks, Vera J.; DeAre, Diana

    The farm population has declined fairly steadily for more than half a century. By 1970 the proportion of the U.S. population residing on farms had fallen to about 5 per cent, and by 1977 had dropped to 3.6 per cent. About 1.4 per cent of the farm population was of Spanish origin (represented for the first time in this year's report), as compared…

  16. Population and population policy in Pakistan.

    PubMed

    Mauldin, W P

    1963-02-01

    Pakistan is a divided country with different religious groups represented. Since independence in 1941, the Muslim population has increased more rapidly than the Hindu population, the West Pakistan population more rapidly and steadily than the East Pakistan population. In the late 1950s the Pakistan government initiated a family planning program. The program has trained medical and paramedical personnel in family planning, added family planning services to existing medical centers, planned for a National Research Institute of Family Planning, employed mobile units to reach outlying areas, conducted limited clinical studies on some contraceptives, and used mass media advertising. Only India and Japan are doing more with government-sponsored family planning. A weak organizational structure and an inadequate number of trained personnel are the main weakness of the program. It is too early to assess the success of the program. A 10-point reduction in annual birth rates will be considered successful.

  17. Epidemiology Characteristics of Constipation for General Population, Pediatric Population, and Elderly Population in China

    PubMed Central

    Chu, Huikuan; Zhong, Likun; Li, Hai; Zhang, Xiujing; Zhang, Jingzhi; Hou, Xiaohua

    2014-01-01

    Objective. To acquire more data about the epidemiologic characteristics of constipation in different kinds of populations in China. Methods. Using “constipation” and “China” as search terms; relevant papers were searched from January 1995 to April 2014. Data on prevalence, gender, diagnostic criteria, geographical area, educational class, age, race, and physician visit results were extracted and analyzed. Results. 36 trials were included. Prevalence rates of constipation in elderly population (18.1%) and pediatric population (18.8%) were significantly higher than that in general population (8.2%). Prevalence of constipation defined by non-Rome criteria was higher than that by Rome criteria in general population. Prevalence rates of constipation were different for different geographical area. People with less education were predisposed to constipation. In pediatric population, prevalence of constipation was the lowest in children aged 2–6 years. Prevalence of constipation in ethnic minorities was higher than that in Han people. People with constipation were predisposed to FD, haemorrhoid, and GERD. Only 22.2% patients seek medical advice in general population. Conclusions. In China, prevalence of constipation was lower compared with most of other countries. The factors including female gender, diagnostic criteria, geographical area, age, educational class, and race seemed to have major effects on prevalence of constipation. PMID:25386187

  18. Regarding the confusion between the population concept and Mayr's "population thinking".

    PubMed

    Hey, Jody

    2011-12-01

    Ernst Mayr said that one of Darwin's greatest contributions was to show scholars the way to population thinking, and to help them discard a mindset of typological thinking. Population thinking rejects a focus on a central representative type, and emphasizes the variation among individuals. However, Mayr's choice of terms has led to confusion, particularly among biologists who study natural populations. Both population thinking and the concept of a biological population were inspired by Darwin, and from Darwin the chain for both concepts runs through Francis Galton who introduced the statistical usage of "population" that appears in Mayr's population thinking. It was Galton's "population" that was modified by geneticists and biometricians in the early 20th century to refer to an interbreeding and evolving community of organisms. Under this meaning, a population is a biological entity and so paradoxically population thinking, which emphasizes variation at the expense of dwelling on entities, is usually not about populations. Mayr did not address the potential for misunderstanding but for him the important part of the population concept was that the organisms within a population were variable, and so he probably thought there should not be confusion between population thinking and the concept of a population.

  19. The Population Reference Bureau's Population Handbook.

    ERIC Educational Resources Information Center

    Haupt, Arthur; Kane, Thomas T.

    This handbook offers information on population dynamics. The population data resource is intended for use by journalists, policymakers, teachers, high school and college students, libraries, advertising agencies, and family planning groups. The document is presented in 12 sections. Section I introduces demography, explains the purpose and scope of…

  20. Population genetic structure of traditional populations in the Peruvian Central Andes and implications for South American population history.

    PubMed

    Cabana, Graciela S; Lewis, Cecil M; Tito, Raúl Y; Covey, R Alan; Cáceres, Angela M; Cruz, Augusto F De La; Durand, Diana; Housman, Genevieve; Hulsey, Brannon I; Iannacone, Gian Carlo; López, Paul W; Martínez, Rolando; Medina, Ángel; Dávila, Olimpio Ortega; Pinto, Karla Paloma Osorio; Santillán, Susan I Polo; Domínguez, Percy Rojas; Rubel, Meagan; Smith, Heather F; Smith, Silvia E; Massa, Verónica Rubín de Celis; Lizárraga, Beatriz; Stone, Anne C

    2014-01-01

    Molecular-based characterizations of Andean peoples are traditionally conducted in the service of elucidating continent-level evolutionary processes in South America. Consequently, genetic variation among "western" Andean populations is often represented in relation to variation among "eastern" Amazon and Orinoco River Basin populations. This west-east contrast in patterns of population genetic variation is typically attributed to large-scale phenomena, such as dual founder colonization events or differing long-term microevolutionary histories. However, alternative explanations that consider the nature and causes of population genetic diversity within the Andean region remain underexplored. Here we examine population genetic diversity in the Peruvian Central Andes using data from the mtDNA first hypervariable region and Y-chromosome short tandem repeats among 17 newly sampled populations and 15 published samples. Using this geographically comprehensive data set, we first reassessed the currently accepted pattern of western versus eastern population genetic structure, which our results ultimately reject: mtDNA population diversities were lower, rather than higher, within Andean versus eastern populations, and only highland Y-chromosomes exhibited significantly higher within-population diversities compared with eastern groups. Multiple populations, including several highland samples, exhibited low genetic diversities for both genetic systems. Second, we explored whether the implementation of Inca state and Spanish colonial policies starting at about ad 1400 could have substantially restructured population genetic variation and consequently constitute a primary explanation for the extant pattern of population diversity in the Peruvian Central Andes. Our results suggest that Peruvian Central Andean population structure cannot be parsimoniously explained as the sole outcome of combined Inca and Spanish policies on the region's population demography: highland populations

  1. Population Projections

    Science.gov Websites

    United States Census Bureau Topics Population Latest Information Age and Sex Ancestry Children Mobility Population Estimates Population Projections Race Veterans Economy Latest Information Portal Other Economic Programs Business Latest Information Business Characteristics Classification Codes

  2. Population

    EPA Science Inventory

    Population growth influences many stressors on Narragansett Bay and its Watershed, including all landscape and chemical stressors discussed in other chapters of this report. In numerous ways, population growth affects the condition of the Bay ecosystem, Watershed ecosystem, and h...

  3. Mapping Air Population

    NASA Astrophysics Data System (ADS)

    Peterson, Michael P.; Hunt, Paul; Weiß, Konrad

    2018-05-01

    "Air population" refers to the total number of people flying above the earth at any point in time. The total number of passengers can then be estimated by multiplying the number of seats for each aircraft by the current seat occupancy rate. Using this method, the estimated air population is determined by state for the airspace over the United States. In the interactive, real-time mapping system, maps are provided to show total air population, the density of air population (air population / area of state), and the ratio of air population to ground population.

  4. European Population Substructure: Clustering of Northern and Southern Populations

    PubMed Central

    Seldin, Michael F; Shigeta, Russell; Villoslada, Pablo; Selmi, Carlo; Tuomilehto, Jaakko; Silva, Gabriel; Belmont, John W; Klareskog, Lars; Gregersen, Peter K

    2006-01-01

    Using a genome-wide single nucleotide polymorphism (SNP) panel, we observed population structure in a diverse group of Europeans and European Americans. Under a variety of conditions and tests, there is a consistent and reproducible distinction between “northern” and “southern” European population groups: most individual participants with southern European ancestry (Italian, Spanish, Portuguese, and Greek) have >85% membership in the “southern” population; and most northern, western, eastern, and central Europeans have >90% in the “northern” population group. Ashkenazi Jewish as well as Sephardic Jewish origin also showed >85% membership in the “southern” population, consistent with a later Mediterranean origin of these ethnic groups. Based on this work, we have developed a core set of informative SNP markers that can control for this partition in European population structure in a variety of clinical and genetic studies. PMID:17044734

  5. Understanding Population.

    ERIC Educational Resources Information Center

    Mothner, Ira

    Activities and concerns of Ford Foundation supported population research and training centers are described in this report. The centers are concerned with population growth, consequences of growth for human welfare, forces that determine family planning, interrelations among population variables, economics of contraceptive distribution, and…

  6. Farm Population of the United States: 1975. Current Population Reports: Farm Population.

    ERIC Educational Resources Information Center

    Banks, Vera J.; And Others

    Presented via narrative and tabular data, this report includes: Population of the U.S., Total and Farm: 1960-1975; Metropolitan-Nonmetropolitan Residence of the Farm and Nonfarm Population, by Race: 1975; Fertility Characteristics of Farm and Nonfarm Women, by Race: 1975; Persons 14 Years Old and Over Employed in Agriculture, by Farm-Nonfarm…

  7. Population information resources.

    PubMed

    Pasquariella, S K

    1984-12-01

    This article describes print and computerized services that are dedicated to bibliographic coverage of 1 or more areas of population studies. Major printed bibliographic information resources for population material include: ADOPT, DOCPAL Resumenes sobre Poblacion en America Latina, PIDSA Abstracts, Population Index and Review of Population Reviews. ADOPT is an annotated computer-aided current-awareness bibliographic journal which has been published monthly since January 1975 by the Regional Population Information Center of the Economic and Social Commission for Asia and the Pacific (ESCAP). DOCPAL Resumenes is a computer-produced biannual collection of abstracts containing indexes and between 600 and 700 summaries of both published and unpublished population documents. PIDSA is intended to make available documentary information about population matters in sub-Saharan Africa. Population Index, 1 of the oldest and most definitive bibliographies in the demography field, is international in scope and is arranged as a classified and annotated bibliography of monographs, journal articles and 2ndary source material relevant to all aspects of demography. Review of Population Reviews, published 4 times a year, are annotated bibliographies containing summaries of articles that have been published in 83 periodicals in 37 countries. Cited articles are assigned subject-heading descriptors from the Population Multilingual Thesaurus. Major computerized information resources are: DOCPAL, DOCPOP, EBIS/POPFILE, MANPINS, POPLINE and POPULATION BIBLIOGRAPHY. DOCPAL was established to assist Latin Ameran countries in the collection, storage, processing and retrieval of population documents about Latin America. DOCPAL contains over 19,000 bibliographic citations. DOCPOP was established as the 1st Latin American national computerized population documentation system for Brazilian material. POPLINE is a computerized retrieval service cooperatively produced in the US which covers the

  8. Population Research.

    ERIC Educational Resources Information Center

    National Inst. of Child Health and Human Development (NIH), Bethesda, MD.

    The scope of population research as carried on by the National Institute of Child Health and Human Development (NICHD) is set forth in this booklet. Population problems of the world, United States, and the individual are considered along with international population policies based on voluntary family planning programs. NICHD goals for biological…

  9. Population structure in Japanese rice population

    PubMed Central

    Yamasaki, Masanori; Ideta, Osamu

    2013-01-01

    It is essential to elucidate genetic diversity and relationships among even related individuals and populations for plant breeding and genetic analysis. Since Japanese rice breeding has improved agronomic traits such as yield and eating quality, modern Japanese rice cultivars originated from narrow genetic resource and closely related. To resolve the population structure and genetic diversity in Japanese rice population, we used a total of 706 alleles detected by 134 simple sequence repeat markers in a total of 114 cultivars composed of 94 improved varieties and 20 landraces, which are representative and important for Japanese rice breeding. The landraces exhibit greater gene diversity than improved lines, suggesting that landraces can provide additional genetic diversity for future breeding. Model-based Bayesian clustering analysis revealed six subgroups and admixture situation in the cultivars, showing good agreement with pedigree information. This method could be superior to phylogenetic method in classifying a related population. The leading Japanese rice cultivar, Koshihikari is unique due to the specific genome constitution. We defined Japanese rice diverse sets that capture the maximum number of alleles for given sample sizes. These sets are useful for a variety of genetic application in Japanese rice cultivars. PMID:23641181

  10. Population policy.

    PubMed

    1987-03-01

    Participants in the Seminar on Population Policies for Top-level Policy Makers and Program Managers, meeting in Thailand during January 1987, examined the challenges now facing them regarding the implementation of fertility regulation programs in their respective countries -- Bangladesh, China, India, Indonesia, Malaysia, Nepal, Pakistan, the Philippines, the Republic of Korea, and Thailand. This Seminar was organized to coincide with the completion of an Economic and Social Commission for Asia and the Pacific (ESCAP) study investigating the impact and efficiency of family planning programs in the region. Country studies were reviewed at the Seminar along with policy issues about the status of women, incentive and disincentive programs, and socioeconomic factors affecting fertility. In Bangladesh the government recognizes population growth as its top priority problem related to the socioeconomic development of the country and is working to promote a reorientation strategy from the previous clinic-oriented to a multidimensional family welfare program. China's family planning program seeks to postpone marraige, space the births of children between 3-5 years, and promote the 1-child family. Its goal is to reduce the rate of natural increase from 12/1000 in 1978 to 5/1000 by 1985 and 0 by 2000. India's 7th Five-Year-Plan (1986-90) calls for establishing a 2-child family norm by 2000. In Indonesia the government's population policy includes reducing the rate of population growth, achieving a redistribution of the population, adjusting economic factors, and creating prosperous families. The government of Indonesia reversed its policy to reduce the population growth rate in 1984 and announced its goal of achieving a population of 70 million by 2100 in order to support mass consumption industries. It has created an income tax deduction system favoring large families and maternity benefits for women who have up to 5 children as incentives. Nepal's official policy is to

  11. Population growth, fecundity, and survivorship in recovering populations of bighorn sheep

    USGS Publications Warehouse

    Singer, F.J.; Williams, E.; Miller, M.W.; Zeigenfuss, L.C.

    2000-01-01

    The single greatest obstacle to the restoration of large, healthy, populations of bighorn sheep (Ovis canadensis) in the western United States is epizootic outbreaks of bronchopneumonia that may kill 20–100% of the animals in populations. Although the species is capable of rapid initial growth rates following restoration into new habitat (λ = 1.23–1.30 have been observed), these rates of increase are typical only a few years following the release of a population, and then most populations either decline to extirpation or remnant status (<30 animals) or remain at <100 individuals. We studied the fecundity and survivorship of three increasing, and three declining and suspected diseased, populations of bighorn sheep (the latter were subjected to outbreaks of bronchopneumonia) located in or near several large national parks in the western United States from 1991 to 1996. Titers verified both population categories were exposed to the bacteria Pasteurella haemolytica serotypes 3; 4; and 3, 4, 10; Moraxella sp., and parainfluenza-3 and bluetongue (BT) viruses. Pregnancy rates of adult ewes were not different in increasing or decreasing populations (pooled rate = 0.93; p = 0.57), but pregnancy rates of yearlings were lower (0.00 for decreasing vs. 0.33 for increasing populations), initial production of lambs and annual recruitment of lambs was lower (0.14, decreasing vs. 0.66, p < 0.05). Adult survival was lower during the first year of an epizootic, 0.62, in one population, but recovered to 0.85 by the second and subsequent years. Survival of adult rams was variable in diseased populations; in two populations rams appeared to be disproportionately impacted, but in a third population rams survived better during the epizootic. In all the increasing park (unhunted) populations, adult ram survival (0.94 ± 0.01) was higher than adult ewe survival (0.89 ± 0.02) (p = 0.10), in contrast to published information from hunted populations where ram survival was lower

  12. Molecular Population Genetics

    PubMed Central

    Casillas, Sònia; Barbadilla, Antonio

    2017-01-01

    Molecular population genetics aims to explain genetic variation and molecular evolution from population genetics principles. The field was born 50 years ago with the first measures of genetic variation in allozyme loci, continued with the nucleotide sequencing era, and is currently in the era of population genomics. During this period, molecular population genetics has been revolutionized by progress in data acquisition and theoretical developments. The conceptual elegance of the neutral theory of molecular evolution or the footprint carved by natural selection on the patterns of genetic variation are two examples of the vast number of inspiring findings of population genetics research. Since the inception of the field, Drosophila has been the prominent model species: molecular variation in populations was first described in Drosophila and most of the population genetics hypotheses were tested in Drosophila species. In this review, we describe the main concepts, methods, and landmarks of molecular population genetics, using the Drosophila model as a reference. We describe the different genetic data sets made available by advances in molecular technologies, and the theoretical developments fostered by these data. Finally, we review the results and new insights provided by the population genomics approach, and conclude by enumerating challenges and new lines of inquiry posed by increasingly large population scale sequence data. PMID:28270526

  13. Counting Populations

    ERIC Educational Resources Information Center

    Damonte, Kathleen

    2004-01-01

    Scientists use sampling to get an estimate of things they cannot easily count. A population is made up of all the organisms of one species living together in one place at the same time. All of the people living together in one town are considered a population. All of the grasshoppers living in a field are a population. Scientists keep track of the…

  14. Farm Population of the United States: 1973. Current Population Reports, Farm Population.

    ERIC Educational Resources Information Center

    Banks, Vera J.; And Others

    Selected characteristics of the United States' farm population for 1973 are presented. The farm population consists of all persons living in rural territory on places of: (1) 10 or more acres if as much as $50 worth of agricultural products were sold from the place in the reporting year and (2) under 10 acres if as much as $250 worth of…

  15. Human Population Problems

    ERIC Educational Resources Information Center

    Emmel, Thomas C.; Sligh, Michael M.

    1970-01-01

    Asserts that overpopulation is the most pressing world problem. Topics discussed include population control in primitive societies, population growth and control in modern societies, methods of motivational population control, consequences of no population control, and mass famines during the 1970's in underdeveloped countries. Cities 33…

  16. Population and Environment

    PubMed Central

    de Sherbinin, Alex; Carr, David; Cassels, Susan; Jiang, Leiwen

    2009-01-01

    The interactions between human population dynamics and the environment have often been viewed mechanistically. This review elucidates the complexities and contextual specificities of population-environment relationships in a number of domains. It explores the ways in which demographers and other social scientists have sought to understand the relationships among a full range of population dynamics (e.g., population size, growth, density, age and sex composition, migration, urbanization, vital rates) and environmental changes. The chapter briefly reviews a number of the theories for understanding population and the environment and then proceeds to provide a state-of-the-art review of studies that have examined population dynamics and their relationship to five environmental issue areas. The review concludes by relating population-environment research to emerging work on human-environment systems. PMID:20011237

  17. Population demographics and genetic diversity in remnant and translocated populations of sea otters

    USGS Publications Warehouse

    Bodkin, James L.; Ballachey, Brenda E.; Cronin, M.A.; Scribner, K.T.

    1999-01-01

    The effects of small population size on genetic diversity and subsequent population recovery are theoretically predicted, but few empirical data are available to describe those relations. We use data from four remnant and three translocated sea otter (Enhydra lutris) populations to examine relations among magnitude and duration of minimum population size, population growth rates, and genetic variation. Metochondrial (mt)DNA haplotype diversity was correlated with the number of years at minimum population size (r = -0.741, p = 0.038) and minimum population size (r = 0.709, p = 0.054). We found no relation between population growth and haplotype diversity, altough growth was significantly greater in translocated than in remnant populations. Haplotype diversity in populations established from two sources was higher than in a population established from a single source and was higher than in the respective source populations. Haplotype frequencies in translocated populations of founding sizes of 4 and 28 differed from expected, indicating genetic drift and differential reproduction between source populations, whereas haplotype frequencies in a translocated population with a founding size of 150 did not. Relations between population demographics and genetic characteristics suggest that genetic sampling of source and translocated populations can provide valuable inferences about translocations.

  18. Individualized population care: linking personal care to population care in general practice.

    PubMed

    Buetow, Stephen; Getz, Linn; Adams, Peter

    2008-10-01

    General practice is increasingly expected to deliver population care to individual patients. The feasibility and ethics of this policy shift have been challenged. Our aim is to suggest how to deliver population care while protecting personal care. We outline and discuss concepts of these types of care, their relation to the prevailing discourse regarding intervention benefits, and arguments for individualized population care. Individualized population care can enable general practice to meet the health targets of individual patients in the light of population-based goals. It unifies the concepts of personal care and whole population care. Personal care focuses on the individual good in particular consultations. Whole population care focuses on the overall health good of a population without reference to the individuality of each population member. These types of care constitute elements of a continuum that varies in purpose and objects of focus. The limitations of a crude dichotomy of personal care and population care are made explicit in a series of five arguments that lend support to the concept of individualized population care. We advocate a constructive but critical attitude towards the idea of population-based interventions in everyday general practice. Traditional personal care and whole population care can theoretically be integrated into individualized population care. However, this presupposes clinical-epidemiological expertise and moral awareness in practising clinicians.

  19. Extinction-effective population index: incorporating life-history variations in population viability analysis.

    PubMed

    Fujiwara, Masami

    2007-09-01

    Viability status of populations is a commonly used measure for decision-making in the management of populations. One of the challenges faced by managers is the need to consistently allocate management effort among populations. This allocation should in part be based on comparison of extinction risks among populations. Unfortunately, common criteria that use minimum viable population size or count-based population viability analysis (PVA) often do not provide results that are comparable among populations, primarily because they lack consistency in determining population size measures and threshold levels of population size (e.g., minimum viable population size and quasi-extinction threshold). Here I introduce a new index called the "extinction-effective population index," which accounts for differential effects of demographic stochasticity among organisms with different life-history strategies and among individuals in different life stages. This index is expected to become a new way of determining minimum viable population size criteria and also complement the count-based PVA. The index accounts for the difference in life-history strategies of organisms, which are modeled using matrix population models. The extinction-effective population index, sensitivity, and elasticity are demonstrated in three species of Pacific salmonids. The interpretation of the index is also provided by comparing them with existing demographic indices. Finally, a measure of life-history-specific effect of demographic stochasticity is derived.

  20. Population.

    ERIC Educational Resources Information Center

    International Planned Parenthood Federation, London (England).

    In an effort to help meet the growing interest and concern about the problems created by the rapid growth of population, The International Planned Parenthood Federation has prepared this booklet with the aim of assisting the study of the history and future trends of population growth and its impact on individual and family welfare, national,…

  1. Population status and population genetics of northern leopard frogs in Arizona

    USGS Publications Warehouse

    Theimer, Tad C.; Drost, Charles A.; O'Donnell, Ryan P.; Mock, Karen E.

    2011-01-01

    Increasing isolation of populations by habitat fragmentation threatens the persistence of many species, both from stochastic loss of small isolated populations, and from inbreeding effects in populations that have become genetically isolated. In the southwestern United States, amphibian habitat is naturally patchy in occurrence because of the prevailing aridity of the region. Streams, rivers, and other wetlands are important both as habitat and as corridors that connect populations. However, populations of some species have become more fragmented and isolated by habitat degradation and loss. Northern leopard frogs (Rana pipiens) have experienced serious declines in the Southwest. We conducted an extensive survey across the known range of northern leopard frogs in Arizona to determine the current distribution and abundance of the species. From a range that once spanned much of the northern and central part of the State, northern leopard frogs have been reduced to three or four widely separated populations, near Lyman Lake in east-central Arizona, in the Stoneman Lake area south of Flagstaff, along Truxton Wash near Peach Springs, and a population of uncertain extent on Navajo Nation lands. The Lyman Lake and Truxton Wash populations are small and extremely isolated. The Stoneman Lake population, however, is an extensive metapopulation spread across several stream drainages, including numerous ponds, wetlands, and artificial tanks. This is the only population in Arizona that is increasing in extent and numbers, but there is concern about the apparent introduction of nonnative genetic stock from eastern North America into this area. We analyzed genetic diversity within and genetic divergence among populations of northern leopard frogs, across both extant and recently extirpated populations in Arizona. We also analyzed mitochondrial DNA to place these populations into a larger phylogenetic framework and to determine whether any populations contained genetic material

  2. Population pharmacogenetics of Ibero-Latinoamerican populations (MESTIFAR 2014).

    PubMed

    Sosa-Macias, Martha; Moya, Graciela E; LLerena, Adrián; Ramírez, Ronald; Terán, Enrique; Peñas-LLedó, Eva M; Tarazona-Santos, Eduardo; Galaviz-Hernández, Carlos; Céspedes-Garro, Carolina; Acosta, Hildaura

    2015-01-01

    MESTIFAR 2014 28-30 November 2014, Panama City, Panama The CEIBA consortium was created within the Ibero-American network of Pharmacogenetics (RIBEF) to study population pharmacogenetics. The current status of these initiatives and results of the MESTIFAR project were analyzed in Panama, 28-30 November 2014. The MESTIFAR project focused on studying CYPs genetic polymorphisms in populations of different ethnic origin. So far, more than 6000 healthy volunteers have been evaluated, making this one of the largest population pharmacogenomic studies worldwide. Three symposia were organized, 'Pharmacogenetics of indigenous and mestizos populations and its clinical implications', 'Methodological innovation in pharmacogenetics and its application in health', and 'General discussion and concluding remarks', about mechanisms and proposals for training, diffusion of pharmacogenetics for Spanish- and Portuguese-speaking health professionals, and 'bench to bedside' pilot projects.

  3. Molecular Population Genetics.

    PubMed

    Casillas, Sònia; Barbadilla, Antonio

    2017-03-01

    Molecular population genetics aims to explain genetic variation and molecular evolution from population genetics principles. The field was born 50 years ago with the first measures of genetic variation in allozyme loci, continued with the nucleotide sequencing era, and is currently in the era of population genomics. During this period, molecular population genetics has been revolutionized by progress in data acquisition and theoretical developments. The conceptual elegance of the neutral theory of molecular evolution or the footprint carved by natural selection on the patterns of genetic variation are two examples of the vast number of inspiring findings of population genetics research. Since the inception of the field, Drosophila has been the prominent model species: molecular variation in populations was first described in Drosophila and most of the population genetics hypotheses were tested in Drosophila species. In this review, we describe the main concepts, methods, and landmarks of molecular population genetics, using the Drosophila model as a reference. We describe the different genetic data sets made available by advances in molecular technologies, and the theoretical developments fostered by these data. Finally, we review the results and new insights provided by the population genomics approach, and conclude by enumerating challenges and new lines of inquiry posed by increasingly large population scale sequence data. Copyright © 2017 Casillas and Barbadilla.

  4. Ancestral Relationships Using Metafounders: Finite Ancestral Populations and Across Population Relationships.

    PubMed

    Legarra, Andres; Christensen, Ole F; Vitezica, Zulma G; Aguilar, Ignacio; Misztal, Ignacy

    2015-06-01

    Recent use of genomic (marker-based) relationships shows that relationships exist within and across base population (breeds or lines). However, current treatment of pedigree relationships is unable to consider relationships within or across base populations, although such relationships must exist due to finite size of the ancestral population and connections between populations. This complicates the conciliation of both approaches and, in particular, combining pedigree with genomic relationships. We present a coherent theoretical framework to consider base population in pedigree relationships. We suggest a conceptual framework that considers each ancestral population as a finite-sized pool of gametes. This generates across-individual relationships and contrasts with the classical view which each population is considered as an infinite, unrelated pool. Several ancestral populations may be connected and therefore related. Each ancestral population can be represented as a "metafounder," a pseudo-individual included as founder of the pedigree and similar to an "unknown parent group." Metafounders have self- and across relationships according to a set of parameters, which measure ancestral relationships, i.e., homozygozities within populations and relationships across populations. These parameters can be estimated from existing pedigree and marker genotypes using maximum likelihood or a method based on summary statistics, for arbitrarily complex pedigrees. Equivalences of genetic variance and variance components between the classical and this new parameterization are shown. Segregation variance on crosses of populations is modeled. Efficient algorithms for computation of relationship matrices, their inverses, and inbreeding coefficients are presented. Use of metafounders leads to compatibility of genomic and pedigree relationship matrices and to simple computing algorithms. Examples and code are given. Copyright © 2015 by the Genetics Society of America.

  5. Ancestral Relationships Using Metafounders: Finite Ancestral Populations and Across Population Relationships

    PubMed Central

    Legarra, Andres; Christensen, Ole F.; Vitezica, Zulma G.; Aguilar, Ignacio; Misztal, Ignacy

    2015-01-01

    Recent use of genomic (marker-based) relationships shows that relationships exist within and across base population (breeds or lines). However, current treatment of pedigree relationships is unable to consider relationships within or across base populations, although such relationships must exist due to finite size of the ancestral population and connections between populations. This complicates the conciliation of both approaches and, in particular, combining pedigree with genomic relationships. We present a coherent theoretical framework to consider base population in pedigree relationships. We suggest a conceptual framework that considers each ancestral population as a finite-sized pool of gametes. This generates across-individual relationships and contrasts with the classical view which each population is considered as an infinite, unrelated pool. Several ancestral populations may be connected and therefore related. Each ancestral population can be represented as a “metafounder,” a pseudo-individual included as founder of the pedigree and similar to an “unknown parent group.” Metafounders have self- and across relationships according to a set of parameters, which measure ancestral relationships, i.e., homozygozities within populations and relationships across populations. These parameters can be estimated from existing pedigree and marker genotypes using maximum likelihood or a method based on summary statistics, for arbitrarily complex pedigrees. Equivalences of genetic variance and variance components between the classical and this new parameterization are shown. Segregation variance on crosses of populations is modeled. Efficient algorithms for computation of relationship matrices, their inverses, and inbreeding coefficients are presented. Use of metafounders leads to compatibility of genomic and pedigree relationship matrices and to simple computing algorithms. Examples and code are given. PMID:25873631

  6. Population Profile of the United States: 1976. Current Population Reports, Population Characteristics, Series P-20, No. 307.

    ERIC Educational Resources Information Center

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

    This booklet summarizes population characteristics of the United States for 1976. A preliminary section of highlights reviews trends in five areas: population growth, social characteristics, population distribution, employment and income, and ethnic groups. The birth rate has declined, and the rate of childlessness has risen. This probably is due…

  7. Detecting population recovery using gametic disequilibrium-based effective population size estimates

    Treesearch

    David A. Tallmon; Robin S. Waples; Dave Gregovich; Michael K. Schwartz

    2012-01-01

    Recovering populations often must meet specific growth rate or abundance targets before their legal status can be changed from endangered or threatened. While the efficacy, power, and performance of population metrics to infer trends in declining populations has received considerable attention, how these same metrics perform when populations are increasing is less...

  8. Predicting Population Curves.

    ERIC Educational Resources Information Center

    Bunton, Matt

    2003-01-01

    Uses graphs to involve students in inquiry-based population investigations on the Wisconsin gray wolf. Requires students to predict future changes in the wolf population, carrying capacity, and deer population. (YDS)

  9. Population inertia and its sensitivity to changes in vital rates and population structure

    USGS Publications Warehouse

    Koons, David N.; Holmes, Randall R.; Grand, James B.

    2007-01-01

    Because the (st)age structure of a population may rarely be stable, studies of transient population dynamics and population momentum are becoming ever more popular. Yet, studies of "population momentum" are restricted in the sense that they describe the inertia of population size resulting from a demographic transition to the stationary population growth rate. Although rarely mentioned, inertia in population size is a general phenomenon and can be produced by any demographic transition or perturbation. Because population size is of central importance in demography, conservation, and management, formulas relating the sensitivity of population inertia to changes in underlying vital rates and population structure could provide much-needed insight into the dynamics of populations with unstable (st)age structure. Here, we derive such formulas, which are readily computable, and provide examples of their potential use in studies of life history and applied arenas of population study. ?? 2007 by the Ecological Society of America.

  10. [Population and development].

    PubMed

    Castanon Romo, R; Sandoval Navarrete, J

    1996-01-01

    This broad survey of the debate concerning the relationship between population growth and economic development discusses the history and current status of world population growth, summarizes several influential theoretical positions on the topic, and proposes that redefinition of women's social role is indispensable if worldwide control of population growth is to be achieved. The introductory section discusses the acceleration of population growth in the second half of the 20th century and the increasing concentration of growth in the poor and developing countries. The positions of those who see in population control a means of promoting economic development and political stability are contrasted to the positions of those who believe that a large and growing population is the key to achieving economic and political progress. The international community, facing great uncertainty about the size, distribution, and well-being of the future world population, is increasingly concerned about the effect of growing numbers on the environment and natural resources. The second section summarizes the works of Malthus, Julian Simon, and the Club of Rome, and analyzes the propositions of demographic transition theory. The conclusion notes that despite uncertainty about the future of world population, development, and health, most of the poorest countries have become aware of the desirability of slowing population growth. A broad redefinition of the social role of women will inevitably accompany the worldwide demographic transition.

  11. Inferring population structure and demographic history using Y-STR data from worldwide populations.

    PubMed

    Xu, Hongyang; Wang, Chuan-Chao; Shrestha, Rukesh; Wang, Ling-Xiang; Zhang, Manfei; He, Yungang; Kidd, Judith R; Kidd, Kenneth K; Jin, Li; Li, Hui

    2015-02-01

    The Y chromosome is one of the best genetic materials to explore the evolutionary history of human populations. Global analyses of Y chromosomal short tandem repeats (STRs) data can reveal very interesting world population structures and histories. However, previous Y-STR works tended to focus on small geographical ranges or only included limited sample sizes. In this study, we have investigated population structure and demographic history using 17 Y chromosomal STRs data of 979 males from 44 worldwide populations. The largest genetic distances have been observed between pairs of African and non-African populations. American populations with the lowest genetic diversities also showed large genetic distances and coancestry coefficients with other populations, whereas Eurasian populations displayed close genetic affinities. African populations tend to have the oldest time to the most recent common ancestors (TMRCAs), the largest effective population sizes and the earliest expansion times, whereas the American, Siberian, Melanesian, and isolated Atayal populations have the most recent TMRCAs and expansion times, and the smallest effective population sizes. This clear geographic pattern is well consistent with serial founder model for the origin of populations outside Africa. The Y-STR dataset presented here provides the most detailed view of worldwide population structure and human male demographic history, and additionally will be of great benefit to future forensic applications and population genetic studies.

  12. Population-based contracting (population health): part II.

    PubMed

    Jacofsky, D J

    2017-11-01

    Modern healthcare contracting is shifting the responsibility for improving quality, enhancing community health and controlling the total cost of care for patient populations from payers to providers. Population-based contracting involves capitated risk taken across an entire population, such that any included services within the contract are paid for by the risk-bearing entity throughout the term of the agreement. Under such contracts, a risk-bearing entity, which may be a provider group, a hospital or another payer, administers the contract and assumes risk for contractually defined services. These contracts can be structured in various ways, from professional fee capitation to full global per member per month diagnosis-based risk. The entity contracting with the payer must have downstream network contracts to provide the care and facilities that it has agreed to provide. Population health is a very powerful model to reduce waste and costs. It requires a deep understanding of the nuances of such contracting and the appropriate infrastructure to manage both networks and risk. Cite this article: Bone Joint J 2017;99-B:1431-4. ©2017 The British Editorial Society of Bone & Joint Surgery.

  13. The association between ALS and population density: A population based study.

    PubMed

    Scott, Kirsten M; Abhinav, Kumar; Wijesekera, Lokesh; Ganesalingam, Jeban; Goldstein, Laura H; Janssen, Anna; Dougherty, Andrew; Willey, Emma; Stanton, Biba R; Turner, Martin R; Ampong, Mary-Ann; Sakel, Mohammed; Orrell, Richard; Howard, Robin; Shaw, Christopher E; Nigel Leigh, P; Al-Chalabi, Ammar

    2010-10-01

    We aimed to assess whether rural residence is associated with amyotrophic lateral sclerosis in the south-east of England using a population based register. Previous studies in different populations have produced contradictory findings. Residence defined by London borough or non-metropolitan district at time of diagnosis was recorded for each incident case in the South-East England ALS Register between 1995 and 2005. Each of the 26 boroughs or districts of the catchment area of the register was classified according to population density. Age- and sex-adjusted incidence of ALS was calculated for each region and the relationship with population density tested by linear regression, thereby controlling for the underlying population structure. We found that population density in region of residence at diagnosis explained 25% of the variance in ALS rates (r = 0.5, p < 0.01). Thus, in this cohort in the south-east of England, people with ALS were more likely to be resident in areas of high population density at diagnosis.

  14. The association between ALS and population density: A population based study

    PubMed Central

    SCOTT, KIRSTEN M.; ABHINAV, KUMAR; WIJESEKERA, LOKESH; GANESALINGAM, JEBAN; GOLDSTEIN, LAURA H.; JANSSEN, ANNA; DOUGHERTY, ANDREW; WILLEY, EMMA; STANTON, BIBA R.; TURNER, MARTIN R.; AMPONG, MARY-ANN; SAKEL, MOHAMMED; ORRELL, RICHARD; HOWARD, ROBIN; SHAW, CHRISTOPHER E.; LEIGH, P. NIGEL; AL-CHALABI, AMMAR

    2011-01-01

    We aimed to assess whether rural residence is associated with amyotrophic lateral sclerosis in the south-east of England using a population based register. Previous studies in different populations have produced contradictory findings. Residence defined by London borough or non-metropolitan district at time of diagnosis was recorded for each incident case in the South-East England ALS Register between 1995 and 2005. Each of the 26 boroughs or districts of the catchment area of the register was classified according to population density. Age- and sex-adjusted incidence of ALS was calculated for each region and the relationship with population density tested by linear regression, thereby controlling for the underlying population structure. We found that population density in region of residence at diagnosis explained 25% of the variance in ALS rates (r = 0.5, p < 0.01). Thus, in this cohort in the south-east of England, people with ALS were more likely to be resident in areas of high population density at diagnosis. PMID:20429684

  15. Population Neuroscience: Dementia Epidemiology Serving Precision Medicine and Population Health.

    PubMed

    Ganguli, Mary; Albanese, Emiliano; Seshadri, Sudha; Bennett, David A; Lyketsos, Constantine; Kukull, Walter A; Skoog, Ingmar; Hendrie, Hugh C

    2018-01-01

    Over recent decades, epidemiology has made significant contributions to our understanding of dementia, translating scientific discoveries into population health. Here, we propose reframing dementia epidemiology as "population neuroscience," blending techniques and models from contemporary neuroscience with those of epidemiology and biostatistics. On the basis of emerging evidence and newer paradigms and methods, population neuroscience will minimize the bias typical of traditional clinical research, identify the relatively homogenous subgroups that comprise the general population, and investigate broader and denser phenotypes of dementia and cognitive impairment. Long-term follow-up of sufficiently large study cohorts will allow the identification of cohort effects and critical windows of exposure. Molecular epidemiology and omics will allow us to unravel the key distinctions within and among subgroups and better understand individuals' risk profiles. Interventional epidemiology will allow us to identify the different subgroups that respond to different treatment/prevention strategies. These strategies will inform precision medicine. In addition, insights into interactions between disease biology, personal and environmental factors, and social determinants of health will allow us to measure and track disease in communities and improve population health. By placing neuroscience within a real-world context, population neuroscience can fulfill its potential to serve both precision medicine and population health.

  16. Population and development.

    PubMed

    Okita, S

    1989-03-01

    This speech on the life and work of Rafael Salas, who had been the first executive director of the UN Population Fund (UNFPA) and who contributed immensely to global awareness of population as a vital issue, inaugurated the Rafael M. Salas Lecture Series at the UN. Salas was concerned with individual rights and socioeconomic development while maintaining a balance between population and the environment. He built a large multinational assistance program for population activities and increased funding from $2.5 million in 1969 to $175 million to support 2500 projects in 130 developing countries. He organized both the 1974 World Population Conference and the 1984 International Conference on Population. In developing countries malnutrition and poverty are intertwined, lowering productivity and making people prone to diseases. Infant and child mortality rises with the malnutrition of mothers, therefore campaigns modelled after the postwar Japanese efforts are needed to improve nutrition, to train dietitians, and to introduce school lunch programs. Population stabilization could also be achieved in developing countries by raising income levels, although in Latin American countries birth rates have stayed the same despite increasing income. Direct measures are effective in reducing the birth rate: primary school education, increased income, improved nutrition, decline in infant mortality, higher status of women, and decisive governmental population policy. The Club of Rome report The Limits to Growth predicted that sometime in the 21st century a sudden decline in both population and industrial capacity will be reached at the present growth trends.

  17. Population and genomic lessons from genetic analysis of two Indian populations.

    PubMed

    Juyal, Garima; Mondal, Mayukh; Luisi, Pierre; Laayouni, Hafid; Sood, Ajit; Midha, Vandana; Heutink, Peter; Bertranpetit, Jaume; Thelma, B K; Casals, Ferran

    2014-10-01

    Indian demographic history includes special features such as founder effects, interpopulation segregation, complex social structure with a caste system and elevated frequency of consanguineous marriages. It also presents a higher frequency for some rare mendelian disorders and in the last two decades increased prevalence of some complex disorders. Despite the fact that India represents about one-sixth of the human population, deep genetic studies from this terrain have been scarce. In this study, we analyzed high-density genotyping and whole-exome sequencing data of a North and a South Indian population. Indian populations show higher differentiation levels than those reported between populations of other continents. In this work, we have analyzed its consequences, by specifically assessing the transferability of genetic markers from or to Indian populations. We show that there is limited genetic marker portability from available genetic resources such as HapMap or the 1,000 Genomes Project to Indian populations, which also present an excess of private rare variants. Conversely, tagSNPs show a high level of portability between the two Indian populations, in contrast to the common belief that North and South Indian populations are genetically very different. By estimating kinship from mates and consanguinity in our data from trios, we also describe different patterns of assortative mating and inbreeding in the two populations, in agreement with distinct mating preferences and social structures. In addition, this analysis has allowed us to describe genomic regions under recent adaptive selection, indicating differential adaptive histories for North and South Indian populations. Our findings highlight the importance of considering demography for design and analysis of genetic studies, as well as the need for extending human genetic variation catalogs to new populations and particularly to those with particular demographic histories.

  18. Simulating Population Growth.

    ERIC Educational Resources Information Center

    Byington, Scott

    1997-01-01

    Presents a strategy to help students grasp the important implications of population growth. Involves an interactive demonstration that allows students to experience exponential and logistic population growth followed by a discussion of the implications of population-growth principles. (JRH)

  19. The population threat.

    PubMed

    Teitelbaum, M S

    1992-01-01

    Commentary is provided on the challenges faced by the new Clinton administration in formulating US key foreign policy initiatives. There is an urgent need to provide balanced and effective foreign aid for reducing high fertility rates in the developing world. There is also a need to effectively monitor the large migrations of populations. Over the past 10 years, the US has not been actively practicing world leadership on population issues. 3 changes in 1993 give impetus to redirect foreign policy: 1) the waning influence of fringe groups who controlled population issues; 2) the campaign promises to restore UN population stabilization programs; and 3) the evidence from the Persian Gulf and Yugoslavia that demographic issues require planning and assessment. Global population growth has been concentrated in the past 40 years, in part due to mortality declines and sustained high fertility. Of significance is the rapidness and momentum of growth. A high percentage are and will be children. Urban population is also growing rapidly in high fertility countries. Countries with high fertility and significant rural-to-urban migration also have large international migrations. The evolution of policy since the 1950s, which for the most part ignored population issues, is discussed. The American debates have been charged with emotionalism: about human sexuality, legitimacy of voluntary fertility control, the role and status of women and men, abortion, intergenerational transfer of obligations, ethnic solidarity and the sovereignty of national borders, and the proper roles of the state versus the marketplace. There have been over 200 years of ideological argument over population issues. The Malthusian argument was that large population size did not increase prosperity, and growth should be limited. The Marxist-Leninist position was that contraception was Malthusian, abortion was a woman's right, and population growth was neutral. By late 1970 the Chinese Maoists adopted the moral

  20. Matrix population models from 20 studies of perennial plant populations

    USGS Publications Warehouse

    Ellis, Martha M.; Williams, Jennifer L.; Lesica, Peter; Bell, Timothy J.; Bierzychudek, Paulette; Bowles, Marlin; Crone, Elizabeth E.; Doak, Daniel F.; Ehrlen, Johan; Ellis-Adam, Albertine; McEachern, Kathryn; Ganesan, Rengaian; Latham, Penelope; Luijten, Sheila; Kaye, Thomas N.; Knight, Tiffany M.; Menges, Eric S.; Morris, William F.; den Nijs, Hans; Oostermeijer, Gerard; Quintana-Ascencio, Pedro F.; Shelly, J. Stephen; Stanley, Amanda; Thorpe, Andrea; Tamara, Ticktin; Valverde, Teresa; Weekley, Carl W.

    2012-01-01

    Demographic transition matrices are one of the most commonly applied population models for both basic and applied ecological research. The relatively simple framework of these models and simple, easily interpretable summary statistics they produce have prompted the wide use of these models across an exceptionally broad range of taxa. Here, we provide annual transition matrices and observed stage structures/population sizes for 20 perennial plant species which have been the focal species for long-term demographic monitoring. These data were assembled as part of the "Testing Matrix Models" working group through the National Center for Ecological Analysis and Synthesis (NCEAS). In sum, these data represent 82 populations with >460 total population-years of data. It is our hope that making these data available will help promote and improve our ability to monitor and understand plant population dynamics.

  1. Matrix population models from 20 studies of perennial plant populations

    USGS Publications Warehouse

    Ellis, Martha M.; Williams, Jennifer L.; Lesica, Peter; Bell, Timothy J.; Bierzychudek, Paulette; Bowles, Marlin; Crone, Elizabeth E.; Doak, Daniel F.; Ehrlen, Johan; Ellis-Adam, Albertine; McEachern, Kathryn; Ganesan, Rengaian; Latham, Penelope; Luijten, Sheila; Kaye, Thomas N.; Knight, Tiffany M.; Menges, Eric S.; Morris, William F.; den Nijs, Hans; Oostermeijer, Gerard; Quintana-Ascencio, Pedro F.; Shelly, J. Stephen; Stanley, Amanda; Thorpe, Andrea; Tamara, Ticktin; Valverde, Teresa; Weekley, Carl W.

    2012-01-01

    Demographic transition matrices are one of the most commonly applied population models for both basic and applied ecological research. The relatively simple framework of these models and simple, easily interpretable summary statistics they produce have prompted the wide use of these models across an exceptionally broad range of taxa. Here, we provide annual transition matrices and observed stage structures/population sizes for 20 perennial plant species which have been the focal species for long-term demographic monitoring. These data were assembled as part of the 'Testing Matrix Models' working group through the National Center for Ecological Analysis and Synthesis (NCEAS). In sum, these data represent 82 populations with >460 total population-years of data. It is our hope that making these data available will help promote and improve our ability to monitor and understand plant population dynamics.

  2. Population-focused nursing: advocacy for vulnerable populations in an RN-BSN program.

    PubMed

    Jones, Melissa; Smith, Paul

    2014-01-01

    The purpose of this article is to describe an innovative learning activity for online RN-BSN students designed to foster advocacy for vulnerable populations. The Vulnerable Population Advocacy Assignment, included as a component of the online Population-Focused Nursing class, provides students with the opportunity to identify and develop an awareness of issues impacting vulnerable populations and to advocate for policy changes that will influence the health of individuals, families, and populations. RN-BSN students build on previous knowledge and skills in professional communication and advocacy as they develop a policy statement designed to address health disparities impacting local, national, and global populations. © 2014 Wiley Periodicals, Inc.

  3. Standard Populations (Millions) for Age-Adjustment - SEER Population Datasets

    Cancer.gov

    Download files containing standard population data for use in statististical software. The files contain the same data distributed with SEER*Stat software. You can also view the standard populations, either 19 age groups or single ages.

  4. Population structure and genomic inbreeding in nine Swiss dairy cattle populations.

    PubMed

    Signer-Hasler, Heidi; Burren, Alexander; Neuditschko, Markus; Frischknecht, Mirjam; Garrick, Dorian; Stricker, Christian; Gredler, Birgit; Bapst, Beat; Flury, Christine

    2017-11-07

    Domestication, breed formation and intensive selection have resulted in divergent cattle breeds that likely exhibit their own genomic signatures. In this study, we used genotypes from 27,612 autosomal single nucleotide polymorphisms to characterize population structure based on 9214 sires representing nine Swiss dairy cattle populations: Brown Swiss (BS), Braunvieh (BV), Original Braunvieh (OB), Holstein (HO), Red Holstein (RH), Swiss Fleckvieh (SF), Simmental (SI), Eringer (ER) and Evolèner (EV). Genomic inbreeding (F ROH ) and signatures of selection were determined by calculating runs of homozygosity (ROH). The results build the basis for a better understanding of the genetic development of Swiss dairy cattle populations and highlight differences between the original populations (i.e. OB, SI, ER and EV) and those that have become more popular in Switzerland as currently reflected by their larger populations (i.e. BS, BV, HO, RH and SF). The levels of genetic diversity were highest and lowest in the SF and BS breeds, respectively. Based on F ST values, we conclude that, among all pairwise comparisons, BS and HO (0.156) differ more than the other pairs of populations. The original Swiss cattle populations OB, SI, ER, and EV are clearly genetically separated from the Swiss cattle populations that are now more common and represented by larger numbers of cows. Mean levels of F ROH ranged from 0.027 (ER) to 0.091 (BS). Three of the original Swiss cattle populations, ER (F ROH : 0.027), OB (F ROH : 0.029), and SI (F ROH : 0.039), showed low levels of genomic inbreeding, whereas it was much higher in EV (F ROH : 0.074). Private signatures of selection for the original Swiss cattle populations are reported for BTA4, 5, 11 and 26. The low levels of genomic inbreeding observed in the original Swiss cattle populations ER, OB and SI compared to the other breeds are explained by a lesser use of artificial insemination and greater use of natural service. Natural service

  5. U.S. Population Data 1969-2016 - SEER Population Data

    Cancer.gov

    Download county population estimates used in SEER*Stat to calculate cancer incidence and mortality rates. The estimates are a modification of the U.S. Census Bureau's Population Estimates Program, in collaboration with National Center for Health Statistics.

  6. Population and prehistory II: Space-limited human populations in constant environments

    PubMed Central

    Puleston, Cedric O.; Tuljapurkar, Shripad

    2010-01-01

    We present a population model to examine the forces that determined the quality and quantity of human life in early agricultural societies where cultivable area is limited. The model is driven by the non-linear and interdependent relationships between the age distribution of a population, its behavior and technology, and the nature of its environment. The common currency in the model is the production of food, on which age-specific rates of birth and death depend. There is a single nontrivial equilibrium population at which productivity balances caloric needs. One of the most powerful controls on equilibrium hunger level is fertility control. Gains against hunger are accompanied by decreases in population size. Increasing worker productivity does increase equilibrium population size but does not improve welfare at equilibrium. As a case study we apply the model to the population of a Polynesian valley before European contact. PMID:18598711

  7. Population and prehistory II: space-limited human populations in constant environments.

    PubMed

    Puleston, Cedric O; Tuljapurkar, Shripad

    2008-09-01

    We present a population model to examine the forces that determined the quality and quantity of human life in early agricultural societies where cultivable area is limited. The model is driven by the non-linear and interdependent relationships between the age distribution of a population, its behavior and technology, and the nature of its environment. The common currency in the model is the production of food, on which age-specific rates of birth and death depend. There is a single non-trivial equilibrium population at which productivity balances caloric needs. One of the most powerful controls on equilibrium hunger level is fertility control. Gains against hunger are accompanied by decreases in population size. Increasing worker productivity does increase equilibrium population size but does not improve welfare at equilibrium. As a case study we apply the model to the population of a Polynesian valley before European contact.

  8. Population Health Measurement: Applying Performance Measurement Concepts in Population Health Settings

    PubMed Central

    Stoto, Michael A.

    2014-01-01

    Introduction: Whether the focus of population-health improvement efforts, the measurement of health outcomes, risk factors, and interventions to improve them are central to achieving collective impact in the population health perspective. And because of the importance of a shared measurement system, appropriate measures can help to ensure the accountability of and ultimately integrate the efforts of public health, the health care delivery sector, and other public and private entities in the community to improve population health. Yet despite its importance, population health measurement efforts in the United States are poorly developed and uncoordinated. Collaborative Measurement Development: To achieve the potential of the population health perspective, public health officials, health system leaders, and others must work together to develop sets of population health measures that are suitable for different purposes yet are harmonized so that together they can help to improve a community’s health. This begins with clearly defining the purpose of a set of measures, distinguishing between outcomes for which all share responsibility and actions to improve health for which the health care sector, public health agencies, and others should be held accountable. Framework for Population Health Measurement: Depending on the purpose of the analysis, then, measurement systems should clearly specify what to measure—in particular the population served (the denominator), what the critical health dimensions are in a measurement framework, and how the measures can be used to ensure accountability. Building on a clear understanding of the purpose and dimensions of population health that must be measured, developers can then choose specific measures using existing data or developing new data sources if necessary, with established validity, reliability, and other scientific characteristics. Rather than indiscriminately choosing among the proliferating data streams, this

  9. Impact of population growth and population ethics on climate change mitigation policy

    PubMed Central

    Scovronick, Noah; Budolfson, Mark B.; Dennig, Francis; Fleurbaey, Marc; Siebert, Asher; Socolow, Robert H.; Spears, Dean; Wagner, Fabian

    2017-01-01

    Future population growth is uncertain and matters for climate policy: higher growth entails more emissions and means more people will be vulnerable to climate-related impacts. We show that how future population is valued importantly determines mitigation decisions. Using the Dynamic Integrated Climate-Economy model, we explore two approaches to valuing population: a discounted version of total utilitarianism (TU), which considers total wellbeing and is standard in social cost of carbon dioxide (SCC) models, and of average utilitarianism (AU), which ignores population size and sums only each time period’s discounted average wellbeing. Under both approaches, as population increases the SCC increases, but optimal peak temperature decreases. The effect is larger under TU, because it responds to the fact that a larger population means climate change hurts more people: for example, in 2025, assuming the United Nations (UN)-high rather than UN-low population scenario entails an increase in the SCC of 85% under TU vs. 5% under AU. The difference in the SCC between the two population scenarios under TU is comparable to commonly debated decisions regarding time discounting. Additionally, we estimate the avoided mitigation costs implied by plausible reductions in population growth, finding that large near-term savings ($billions annually) occur under TU; savings under AU emerge in the more distant future. These savings are larger than spending shortfalls for human development policies that may lower fertility. Finally, we show that whether lowering population growth entails overall improvements in wellbeing—rather than merely cost savings—again depends on the ethical approach to valuing population. PMID:29087298

  10. [The relationships between population and economy, and between population and education].

    PubMed

    Yu, W

    1981-01-01

    The relationship between population and economy is regarded seriously by China and other countries. This problem can be analyzed and studied under 2 aspects: 1) the influence of economic development on changes in population, and 2) the influence of population increases on economic development. Under the 1st aspect, improved living conditions, hygiene, and health care generally result in lowered mortality rates. Improved economic conditions in China also increased the birthrate and at the same time increased birth control among the people; the increased birthrate was due to more marriages after liberation. In economically advanced countries, due to high expenses in raising children, people tend to limit family sizes to 2 children/family. Under the 2nd aspect, population increases place strains on the food supply and nutritional requirements, especially when increases are too rapid. They also demand more educational resources and influence quality of education. As there are currently 210 million students in China, the quality of education suffers, particularly at the college level, since most of Chinese manpower, physical and financial resources are spent on primary and secondary education. In terms of housing, transportation, health care, and natural resources, they are all intimately related to and influenced by increases in population. Consequently, the living standard would be difficult to raise if population increases are too rapid. Since 1971, population increases have been incorporated into 5-yearly and later yearly national economic plans in China. The large Chinese population is a major obstacle in raising the Chinese economic level, hence a well-planned population control program is essential.

  11. [Economic growth with zero population growth and with declining population].

    PubMed

    Kurz, R

    1982-05-01

    The effects of both zero population growth and a declining population on economic growth are considered. Although the neoclassical theory of economic growth leads to optimistic results in such cases, the author suggests that this theory cannot be used as a basis for political action. The need for further research into the economic effects of a stationary or declining population is stressed. (summary in ENG)

  12. Population and prehistory I: Food-dependent population growth in constant environments.

    PubMed

    Lee, Charlotte T; Tuljapurkar, Shripad

    2008-06-01

    We present a demographic model that describes the feedbacks between food supply, human mortality and fertility rates, and labor availability in expanding populations, where arable land area is not limiting. This model provides a quantitative framework to describe how environment, technology, and culture interact to influence the fates of preindustrial agricultural populations. We present equilibrium conditions and derive approximations for the equilibrium population growth rate, food availability, and other food-dependent measures of population well-being. We examine how the approximations respond to environmental changes and to human choices, and find that the impact of environmental quality depends upon whether it manifests through agricultural yield or maximum (food-independent) survival rates. Human choices can complement or offset environmental effects: greater labor investments increase both population growth and well-being, and therefore can counteract lower agricultural yield, while fertility control decreases the growth rate but can increase or decrease well-being. Finally we establish equilibrium stability criteria, and argue that the potential for loss of local stability at low population growth rates could have important consequences for populations that suffer significant environmental or demographic shocks.

  13. Populations, Teacher's Guide.

    ERIC Educational Resources Information Center

    Conard, David; Lawson, Chester A.

    This Teacher's Guide is designed for use with the Science Curriculum Improvement Study's (SCIS) unit Population. Populations is the third of a six-unit sequence of SCIS's Life Science Program for grades K-6. The Populations guide consists of activity outlines along with suggestions for guiding children's observation and manipulations of living…

  14. Impact of population growth and population ethics on climate change mitigation policy.

    PubMed

    Scovronick, Noah; Budolfson, Mark B; Dennig, Francis; Fleurbaey, Marc; Siebert, Asher; Socolow, Robert H; Spears, Dean; Wagner, Fabian

    2017-11-14

    Future population growth is uncertain and matters for climate policy: higher growth entails more emissions and means more people will be vulnerable to climate-related impacts. We show that how future population is valued importantly determines mitigation decisions. Using the Dynamic Integrated Climate-Economy model, we explore two approaches to valuing population: a discounted version of total utilitarianism (TU), which considers total wellbeing and is standard in social cost of carbon dioxide (SCC) models, and of average utilitarianism (AU), which ignores population size and sums only each time period's discounted average wellbeing. Under both approaches, as population increases the SCC increases, but optimal peak temperature decreases. The effect is larger under TU, because it responds to the fact that a larger population means climate change hurts more people: for example, in 2025, assuming the United Nations (UN)-high rather than UN-low population scenario entails an increase in the SCC of 85% under TU vs. 5% under AU. The difference in the SCC between the two population scenarios under TU is comparable to commonly debated decisions regarding time discounting. Additionally, we estimate the avoided mitigation costs implied by plausible reductions in population growth, finding that large near-term savings ($billions annually) occur under TU; savings under AU emerge in the more distant future. These savings are larger than spending shortfalls for human development policies that may lower fertility. Finally, we show that whether lowering population growth entails overall improvements in wellbeing-rather than merely cost savings-again depends on the ethical approach to valuing population. Copyright © 2017 the Author(s). Published by PNAS.

  15. Population Education Country Programmes.

    ERIC Educational Resources Information Center

    Population Education in Asia and the Pacific Newsletter, 1983

    1983-01-01

    Describes population programs in Afghanistan (nonformal, population education literacy program), India (problems in planning/managing population education in higher education), Indonesia (training for secondary/out-of-school inspectors), and Pakistan (integration of population education into school curricula). Programs in China, Korea, Vietnam,…

  16. WHAT IS A POPULATION?

    EPA Science Inventory

    The word "population" has several meanings, a situation that can lead to confusion in risk assessments. A management goal "to protect wildlife populations," for example, might relate to populations as defined by population biologists, or it might mean simply to protect animals in...

  17. Iowa Population Trends.

    ERIC Educational Resources Information Center

    Tait, John L.; Johnson, Arthur H.

    The trends in population distribution and the composition of Iowa's population are reported in this document in order to provide the leaders and citizens of Iowa with information to assist them in making decisions relating to growth and development. Birth and death rates, rural and urban residence, population by race, and age structure are…

  18. Population demographics of two local South Carolina mourning dove populations

    USGS Publications Warehouse

    McGowan, D.P.; Otis, D.L.

    1998-01-01

    The mourning dove (Zenaida macroura) call-count index had a significant (P 2,300 doves and examined >6,000 individuals during harvest bag checks. An age-specific band recovery model with time- and area-specific recovery rates, and constant survival rates, was chosen for estimation via Akaike's Information Criterion (AIC), likelihood ratio, and goodness-of-fit criteria. After-hatching-year (AHY) annual survival rate was 0.359 (SE = 0.056), and hatching-year (HY) annual survival rate was 0.118 (SE = 0.042). Average estimated recruitment per adult female into the prehunting season population was 3.40 (SE = 1.25) and 2.32 (SE = 0.46) for the 2 study areas. Our movement data support earlier hypotheses of nonmigratory breeding and harvested populations in South Carolina. Low survival rates and estimated population growth rate in the study areas may be representative only of small-scale areas that are heavily managed for dove hunting. Source-sink theory was used to develop a model of region-wide populations that is composed of source areas with positive growth rates and sink areas of declining growth. We suggest management of mourning doves in the Southeast might benefit from improved understanding of local population dynamics, as opposed to regional-scale population demographics.

  19. Population redistribution in Nigeria.

    PubMed

    Adebayo, A

    1984-07-01

    One of the major consequences of the reorganization of Nigeria from 4 states into 12 states in 1967 and then into 19 states in the late 1970s was the redistribution of the Nigerian population. Prior to 1967 Nigeria's rural population migrated primarily to the 4 state capitals of Kaduna, Ibadan, Enugu, Benin City and to the federal capital of Lagos. The creation of additional states, each with their own capital, provided new urban environments where migrants from rural areas were afforded opportunities for employment and social mobility. Between 1960-1980, World Bank estimates indicate that 1) population in Nigerian cityes of over 500,000 population increased from 22-57%; 2) the number of cities with a population of 500,000 or more increased from 2 to 9 and 3) the urban population increased from 13-20%. Given Nigeria's estimated population growth rate of 3.6%/year, it is imperative that the goverment continue its decentralization efforts. Tables show 1) population by region based on the 1963 census; 2) estimated population of the 19 state capitals for 1963 and 1975; and 3) estimated population of the areas included in each of the 19 states for 196o, 1977, 1979, and 19819

  20. Sink populations in carnivore management: cougar demography and immigration in a hunted population.

    PubMed

    Robinson, Hugh S; Wielgus, Robert B; Cooley, Hilary S; Cooley, Skye W

    2008-06-01

    Carnivores are widely hunted for both sport and population control, especially where they conflict with human interests. It is widely believed that sport hunting is effective in reducing carnivore populations and related human-carnivore conflicts, while maintaining viable populations. However, the way in which carnivore populations respond to harvest can vary greatly depending on their social structure, reproductive strategies, and dispersal patterns. For example, hunted cougar (Puma concolor) populations have shown a great degree of resiliency. Although hunting cougars on a broad geographic scale (> 2000 km2) has reduced densities, hunting of smaller areas (i.e., game management units, < 1000 km2), could conceivably fail because of increased immigration from adjacent source areas. We monitored a heavily hunted population from 2001 to 2006 to test for the effects of hunting at a small scale (< 1000 km2) and to gauge whether population control was achieved (lambda < or = 1.0) or if hunting losses were negated by increased immigration allowing the population to remain stable or increase (lambda > or = 1.0). The observed growth rate of 1.00 was significantly higher than our predicted survival/fecundity growth rates (using a Leslie matrix) of 0.89 (deterministic) and 0.84 (stochastic), with the difference representing an 11-16% annual immigration rate. We observed no decline in density of the total population or the adult population, but a significant decrease in the average age of independent males. We found that the male component of the population was increasing (observed male population growth rate, lambda(OM) = 1.09), masking a decrease in the female component (lambda(OF) = 0.91). Our data support the compensatory immigration sink hypothesis; cougar removal in small game management areas (< 1000 km2) increased immigration and recruitment of younger animals from adjacent areas, resulting in little or no reduction in local cougar densities and a shift in population

  1. The New Population Debate: Two Views on Population Growth and Economic Development. Population Trends and Public Policy, Number 7.

    ERIC Educational Resources Information Center

    King, Timothy; Kelley, Allen C.

    Articles representing two views on the issue of rapid population growth and economic development are presented. Although the authors present different perspectives, they agree on many of the fundamentals. For example, both reject alarmism about impending "population explosions" and the use of population as a scapegoat for all Third World…

  2. Including the Group Quarters Population in the US Synthesized Population Database

    PubMed Central

    Chasteen, Bernadette M.; Wheaton, William D.; Cooley, Philip C.; Ganapathi, Laxminarayana; Wagener, Diane K.

    2011-01-01

    In 2005, RTI International researchers developed methods to generate synthesized population data on US households for the US Synthesized Population Database. These data are used in agent-based modeling, which simulates large-scale social networks to test how changes in the behaviors of individuals affect the overall network. Group quarters are residences where individuals live in close proximity and interact frequently. Although the Synthesized Population Database represents the population living in households, data for the nation’s group quarters residents are not easily quantified because of US Census Bureau reporting methods designed to protect individuals’ privacy. Including group quarters population data can be an important factor in agent-based modeling because the number of residents and the frequency of their interactions are variables that directly affect modeling results. Particularly with infectious disease modeling, the increased frequency of agent interaction may increase the probability of infectious disease transmission between individuals and the probability of disease outbreaks. This report reviews our methods to synthesize data on group quarters residents to match US Census Bureau data. Our goal in developing the Group Quarters Population Database was to enable its use with RTI’s US Synthesized Population Database in the Modeling of Infectious Diseases Agent Study. PMID:21841972

  3. Population Structure of Barley Landrace Populations and Gene-Flow with Modern Varieties

    PubMed Central

    Bellucci, Elisa; Bitocchi, Elena; Rau, Domenico; Nanni, Laura; Ferradini, Nicoletta; Giardini, Alessandro; Rodriguez, Monica; Attene, Giovanna; Papa, Roberto

    2013-01-01

    Landraces are heterogeneous plant varieties that are reproduced by farmers as populations that are subject to both artificial and natural selection. Landraces are distinguished by farmers due to their specific traits, and different farmers often grow different populations of the same landrace. We used simple sequence repeats (SSRs) to analyse 12 barley landrace populations from Sardinia from two collections spanning 10 years. We analysed the population structure, and compared the population diversity of the landraces that were collected at field level (population). We used a representative pool of barley varieties for diversity comparisons and to analyse the effects of gene flow from modern varieties. We found that the Sardinian landraces are a distinct gene pool from those of both two-row and six-row barley varieties. There is also a low, but significant, mean level and population-dependent level of introgression from the modern varieties into the Sardinian landraces. Moreover, we show that the Sardinian landraces have the same level of gene diversity as the representative sample of modern commercial varieties grown in Italy in the last decades, even within population level. Thus, these populations represent crucial sources of germplasm that will be useful for crop improvement and for population genomics studies and association mapping, to identify genes, loci and genome regions responsible for adaptive variations. Our data also suggest that landraces are a source of valuable germplasm for sustainable agriculture in the context of future climate change, and that in-situ conservation strategies based on farmer use can preserve the genetic identity of landraces while allowing adaptation to local environments. PMID:24386303

  4. Estimating Traveler Populations at Airport and Cruise Terminals for Population Distribution and Dynamics

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

    Jochem, Warren C; Sims, Kelly M; Bright, Eddie A

    In recent years, uses of high-resolution population distribution databases are increasing steadily for environmental, socioeconomic, public health, and disaster-related research and operations. With the development of daytime population distribution, temporal resolution of such databases has been improved. However, the lack of incorporation of transitional population, namely business and leisure travelers, leaves a significant population unaccounted for within the critical infrastructure networks, such as at transportation hubs. This paper presents two general methodologies for estimating passenger populations in airport and cruise port terminals at a high temporal resolution which can be incorporated into existing population distribution models. The methodologies are geographicallymore » scalable and are based on, and demonstrate how, two different transportation hubs with disparate temporal population dynamics can be modeled utilizing publicly available databases including novel data sources of flight activity from the Internet which are updated in near-real time. The airport population estimation model shows great potential for rapid implementation for a large collection of airports on a national scale, and the results suggest reasonable accuracy in the estimated passenger traffic. By incorporating population dynamics at high temporal resolutions into population distribution models, we hope to improve the estimates of populations exposed to or at risk to disasters, thereby improving emergency planning and response, and leading to more informed policy decisions.« less

  5. Patterns of admixture and population structure in native populations of Northwest North America.

    PubMed

    Verdu, Paul; Pemberton, Trevor J; Laurent, Romain; Kemp, Brian M; Gonzalez-Oliver, Angelica; Gorodezky, Clara; Hughes, Cris E; Shattuck, Milena R; Petzelt, Barbara; Mitchell, Joycelynn; Harry, Harold; William, Theresa; Worl, Rosita; Cybulski, Jerome S; Rosenberg, Noah A; Malhi, Ripan S

    2014-08-01

    The initial contact of European populations with indigenous populations of the Americas produced diverse admixture processes across North, Central, and South America. Recent studies have examined the genetic structure of indigenous populations of Latin America and the Caribbean and their admixed descendants, reporting on the genomic impact of the history of admixture with colonizing populations of European and African ancestry. However, relatively little genomic research has been conducted on admixture in indigenous North American populations. In this study, we analyze genomic data at 475,109 single-nucleotide polymorphisms sampled in indigenous peoples of the Pacific Northwest in British Columbia and Southeast Alaska, populations with a well-documented history of contact with European and Asian traders, fishermen, and contract laborers. We find that the indigenous populations of the Pacific Northwest have higher gene diversity than Latin American indigenous populations. Among the Pacific Northwest populations, interior groups provide more evidence for East Asian admixture, whereas coastal groups have higher levels of European admixture. In contrast with many Latin American indigenous populations, the variance of admixture is high in each of the Pacific Northwest indigenous populations, as expected for recent and ongoing admixture processes. The results reveal some similarities but notable differences between admixture patterns in the Pacific Northwest and those in Latin America, contributing to a more detailed understanding of the genomic consequences of European colonization events throughout the Americas.

  6. Patterns of Admixture and Population Structure in Native Populations of Northwest North America

    PubMed Central

    Verdu, Paul; Pemberton, Trevor J.; Laurent, Romain; Kemp, Brian M.; Gonzalez-Oliver, Angelica; Gorodezky, Clara; Hughes, Cris E.; Shattuck, Milena R.; Petzelt, Barbara; Mitchell, Joycelynn; Harry, Harold; William, Theresa; Worl, Rosita; Cybulski, Jerome S.; Rosenberg, Noah A.; Malhi, Ripan S.

    2014-01-01

    The initial contact of European populations with indigenous populations of the Americas produced diverse admixture processes across North, Central, and South America. Recent studies have examined the genetic structure of indigenous populations of Latin America and the Caribbean and their admixed descendants, reporting on the genomic impact of the history of admixture with colonizing populations of European and African ancestry. However, relatively little genomic research has been conducted on admixture in indigenous North American populations. In this study, we analyze genomic data at 475,109 single-nucleotide polymorphisms sampled in indigenous peoples of the Pacific Northwest in British Columbia and Southeast Alaska, populations with a well-documented history of contact with European and Asian traders, fishermen, and contract laborers. We find that the indigenous populations of the Pacific Northwest have higher gene diversity than Latin American indigenous populations. Among the Pacific Northwest populations, interior groups provide more evidence for East Asian admixture, whereas coastal groups have higher levels of European admixture. In contrast with many Latin American indigenous populations, the variance of admixture is high in each of the Pacific Northwest indigenous populations, as expected for recent and ongoing admixture processes. The results reveal some similarities but notable differences between admixture patterns in the Pacific Northwest and those in Latin America, contributing to a more detailed understanding of the genomic consequences of European colonization events throughout the Americas. PMID:25122539

  7. Population priorities: the challenge of continued rapid population growth.

    PubMed

    Turner, Adair

    2009-10-27

    Rapid population growth continues in the least developed countries. The revisionist case that rapid population could be overcome by technology, that population density was advantageous, that capital shallowing is not a vital concern and that empirical investigations had not proved a correlation between high population growth and low per capita income was both empirically and theoretically flawed. In the modern world, population density does not play the role it did in nineteenth-century Europe and rates of growth in some of today's least developed nations are four times than those in nineteenth-century Europe, and without major accumulation of capital per capita, no major economy has or is likely to make the low- to middle-income transition. Though not sufficient, capital accumulation for growth is absolutely essential to economic growth. While there are good reasons for objecting to the enforced nature of the Chinese one-child policy, we should not underestimate the positive impact which that policy has almost certainly had and will have over the next several decades on Chinese economic performance. And a valid reticence about telling developing countries that they must contain fertility should not lead us to underestimate the severely adverse impact of high fertility rates on the economic performance and prospects of many countries in Africa and the Middle East.

  8. Why Population in 1974?

    ERIC Educational Resources Information Center

    O'Connor, Marion

    1974-01-01

    Discusses the impact of world population growth leading to the establishment of the United Nations Fund for Population Activities and to the declaration of 1974 as World Population Year. Previews some of the parameters and interconnecting interests to be considered during this year of intensive population study. (JR)

  9. Population Blocks.

    ERIC Educational Resources Information Center

    Smith, Martin H.

    1992-01-01

    Describes an educational game called "Population Blocks" that is designed to illustrate the concept of exponential growth of the human population and some potential effects of overpopulation. The game material consists of wooden blocks; 18 blocks are painted green (representing land), 7 are painted blue (representing water); and the remaining…

  10. [The Marxist outlook on population].

    PubMed

    Qin, R

    1984-09-29

    Marxist population theory and world population are discussed. From his study of capitalist population theory Marx concluded, "In capitalist reproduction, poverty produces population," thus rejecting Malthusian population determinism theory and developing economic determinism. According to UN statistics, world population has stabilized since the middle of this century after having doubled every hundred years for the last 300; population in the developed countries showed a positive decrease and average net population growth of the developing countries also decreased. The premise of this paper is that population grows according to social economy development. During the last several hundred years, world wealth increased much faster than population; in the last 200 years alone, the population has increased fivefold, but wealth fortyfold. In addition, world population analysis reveals an inverse relationship between wealth and population in the developed and developing countries: the poorer the country, the greater the population. From this perspective, the study of population must begin with surplus labor. Accumulation of surplus production is the foundation of continuous social development and the basis for population growth. The major difference in methods between capitalist countries and China is that the capitalist-planned fertility affects the individual family while Chinese-planned fertility has the whole nation in mind. Human fertility is determined by the economic system. Private ownership determines the private nature of fertility and public ownership determines the public nature of fertility. Thus population development is determined by the accumulation of social wealth.

  11. Population data of five genetic markers in the Turkish population: comparison with four American population groups.

    PubMed

    Kurtuluş-Ulküer, M; Ulküer, U; Kesici, T; Menevşe, S

    2002-09-01

    In this study, the phenotype and allele frequencies of five enzyme systems were determined in a total of 611 unrelated Turkish individuals and analyzed by using the exact and the chi 2 test. The following five red cell enzymes were identified by cellulose acetate electrophoresis: phosphoglucomutase (PGM), adenosine deaminase (ADA), phosphoglucose isomerase (PGI), adenylate kinase (AK), and 6-phosphogluconate dehydrogenase (6-PGD). The ADA, PGM and AK enzymes were found to be polymorphic in the Turkish population. The results of the statistical analysis showed, that the phenotype frequencies of the five enzyme under study are in Hardy-Weinberg equilibrium. Statistical analysis was performed in order to examine whether there are significant differences in the phenotype frequencies between the Turkish population and four American population groups. This analysis showed, that there are some statistically significant differences between the Turkish and the other groups. Moreover, the observed phenotype and allele frequencies were compared with those obtained in other population groups of Turkey.

  12. Population limitation in a non-cyclic arctic fox population in a changing climate.

    PubMed

    Pálsson, Snæbjörn; Hersteinsson, Páll; Unnsteinsdóttir, Ester R; Nielsen, Ólafur K

    2016-04-01

    Arctic foxes Vulpes lagopus (L.) display a sharp 3- to 5-year fluctuation in population size where lemmings are their main prey. In areas devoid of lemmings, such as Iceland, they do not experience short-term fluctuations. This study focusses on the population dynamics of the arctic fox in Iceland and how it is shaped by its main prey populations. Hunting statistics from 1958-2003 show that the population size of the arctic fox was at a maximum in the 1950s, declined to a minimum in the 1970s, and increased steadily until 2003. Analysis of the arctic fox population size and their prey populations suggests that fox numbers were limited by rock ptarmigan numbers during the decline period. The recovery of the arctic fox population was traced mostly to an increase in goose populations, and favourable climatic conditions as reflected by the Subpolar Gyre. These results underscore the flexibility of a generalist predator and its responses to shifting food resources and climate changes.

  13. Making a stand: five centuries of population growth in colonizing populations of Pinus ponderosa.

    PubMed

    Lesser, Mark R; Jackson, Stephen T

    2012-05-01

    The processes underlying the development of new populations are important for understanding how species colonize new territory and form viable long-term populations. Life-history-mediated processes such as Allee effects and dispersal capability may interact with climate variability and site-specific factors to govern population success and failure over extended time frames. We studied four disjunct populations of ponderosa pine in the Bighorn Basin of north-central Wyoming to examine population growth spanning more than five centuries. The study populations are separated from continuous ponderosa pine forest by distances ranging from 15 to >100 km. Strong evidence indicates that the initial colonizing individuals are still present, yielding a nearly complete record of population history. All trees in each population were aged using dendroecological techniques. The populations were all founded between 1530 and 1655 cal yr CE. All show logistic growth patterns, with initial exponential growth followed by a slowing during the mid to late 20th century. Initial population growth was slower than expectations from a logistic regression model at all four populations, but increased during the mid-18th century. Initial lags in population growth may have been due to strong Allee effects. A combination of overcoming Allee effects and a transition to favorable climate conditions may have facilitated a mid-18th century pulse in population growth rate.

  14. Some Current Population Trends.

    ERIC Educational Resources Information Center

    Taeuber, Conrad

    Population trends in the 1960's and early 1970's are examined in this 1972 speech in terms of overall national trends, the growth of metropolitan areas, the rural population, geographic shifts, internal migration, the black population, and living arrangements. It is noted that population growth in the 1960's was unevenly distributed within age…

  15. Population catastrophe.

    PubMed

    Ankomah, B

    1990-07-01

    UNFPA estimates predict that Africa's population will be 1.5 billion by 2025. In the next 10 years the growth rate will be 3%, the highest for any region in human history. Nigeria is expected to have 301 million people in 35 years, making it the 3rd largest country behind India and China. Currently the economies of African countries can not provide enough jobs or food for the current population. What is going to happen in 35 years when the population will almost double? In 1950 Africa only made up 9% of the world population, but by 2025 it will be 18.4% of a global population of 8.4 billion. Currently half of Africa's population is under 15. This means that there is still time to affect change. There is time to convince this generation not to behave like their parents. A 2 child limit per family is an absolute limit if any progress is to be made that will actually have an effect. Many have suggested that the young people should go back to the land instead of living in poverty in the city. However, currently the land distribution is 0.4 hectares/rural person. This figure is going to drop to 0.29/rural person. Migration is simply not the solution. Many rural farmers want to have enough children to ensure that their land is inherited and stays in the family. The same goal can be achieved, with less children. According to the UNFPA 77% of married women who do not want to have more children do not use contraceptives. Only 14% of African women use contraceptives, so that by age 20 50% of African women have had 1 birth. The only way to seriously cut down the birth rate is to get the men of Africa involved in contraceptive use.

  16. Peru: population and policy.

    PubMed

    Sobrevilla, L A

    1987-06-01

    Peru's 1985 Population Policy Law states as its second objective that individuals and couples should be well informed and provided with the education and health services that will assist them in making responsible decisions about the number and spacing of their children. Thus, the law establishes a firm basis for IEC programs. With regard to population education, the purpose of the law is to create awareness through all educational channels of the reciprocal influence of population dynamics and socioeconomic development and to promote positive attitudes toward small family size. The law promotes the use of the communications media to educate and inform about population issues. The National Population Council, which coordinates and supervises the IEC activities of public sector agencies, has issued publications and audiovisual materials, conducted meetings with government officials and opinion leaders, and promoted awareness of population policy as a key part of development planning. In 1984, the Council organized the First National Seminar on Communication and Population to review activities, set the basis for intersectoral coordination, unify criteria, and review population policy concepts and language. The Ministry of Health carries out IEC activities as part of its family planning services program. In addition, the Ministry of Education has organized a national population education program that aims to revise school curricula to include a greater emphasis on population dynamics and family life education. The activities of a number of private institutions complement the IEC work public sector organizations.

  17. Estimation of effective population size in continuously distributed populations: There goes the neighborhood

    Treesearch

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

    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...

  18. Rapid population growth.

    PubMed

    1972-01-01

    At the current rate of population growth, world population by 2000 is expected to reach 7 billion or more, with developing countries accounting for some 5.4 billion, and economically advanced nations accounting for 1.6 billion. 'Population explosion' is the result of falling mortality rates and continuing high birth rates. Many European countries, and Japan, have already completed what is termed as demographic transition, that is, birth rates have fallen to below 20 births per 1000 population, death rates to 10/1000 population, and annual growth rates are 1% or less; annual growth rates for less developed countries ranged from 2 to 3.5%. Less developed countries can be divided into 3 groups: 1) countries with both high birth and death rates; 2) countries with high birth rates and low death rates; and 3) countries with intermediate and declining birth rates and low death rates. Rapid population growth has serious economic consequences. It encourages inequities in income distribution; it limits rate of growth of gross national product by holding down level of savings and capital investments; it exerts pressure on agricultural production and land; and it creates unemployment problems. In addition, the quality of education for increasing number of chidren is adversely affected, as high proportions of children reduce the amount that can be spent for the education of each child out of the educational budget; the cost and adequacy of health and welfare services are affected in a similar way. Other serious consequences of rapid population growth are maternal death and illness, and physical and mental retardation of children of very poor families. It is very urgent that over a billion births be prevented in the next 30 years to reduce annual population growth rate from the current 2% to 1% per year.

  19. Feedback between Population and Evolutionary Dynamics Determines the Fate of Social Microbial Populations

    PubMed Central

    Sanchez, Alvaro; Gore, Jeff

    2013-01-01

    The evolutionary spread of cheater strategies can destabilize populations engaging in social cooperative behaviors, thus demonstrating that evolutionary changes can have profound implications for population dynamics. At the same time, the relative fitness of cooperative traits often depends upon population density, thus leading to the potential for bi-directional coupling between population density and the evolution of a cooperative trait. Despite the potential importance of these eco-evolutionary feedback loops in social species, they have not yet been demonstrated experimentally and their ecological implications are poorly understood. Here, we demonstrate the presence of a strong feedback loop between population dynamics and the evolutionary dynamics of a social microbial gene, SUC2, in laboratory yeast populations whose cooperative growth is mediated by the SUC2 gene. We directly visualize eco-evolutionary trajectories of hundreds of populations over 50–100 generations, allowing us to characterize the phase space describing the interplay of evolution and ecology in this system. Small populations collapse despite continual evolution towards increased cooperative allele frequencies; large populations with a sufficient number of cooperators “spiral” to a stable state of coexistence between cooperator and cheater strategies. The presence of cheaters does not significantly affect the equilibrium population density, but it does reduce the resilience of the population as well as its ability to adapt to a rapidly deteriorating environment. Our results demonstrate the potential ecological importance of coupling between evolutionary dynamics and the population dynamics of cooperatively growing organisms, particularly in microbes. Our study suggests that this interaction may need to be considered in order to explain intraspecific variability in cooperative behaviors, and also that this feedback between evolution and ecology can critically affect the demographic fate

  20. Use of Population Genetics to Assess the Ecology, Evolution, and Population Structure of Coccidioides

    PubMed Central

    Teixeira, Marcus M.

    2016-01-01

    During the past 20 years, a general picture of the genetic diversity and population structure of Coccidioides, the causal agent of coccidioidomycosis (Valley fever), has emerged. The genus consists of 2 genetically diverse species, C. immitis and C. posadasii, each of which contains 1 or more distinct populations with limited gene flow. Genotypic data indicate that C. immitis is divided into 2 subpopulations (central and southern California populations) and C. posadasii is divided into 3 subpopulations (Arizona, Mexico, and Texas/South America populations). However, admixture within and among these populations and the current paucity of environmental isolates limit our understanding of the population genetics of Coccidioides. We assessed population structure of Coccidioides in Arizona by analyzing 495 clinical and environmental isolates. Our findings confirm the population structure as previously described and indicate a finer scale population structure in Arizona. Environmental isolates appear to have higher genetic diversity than isolates from human patients. PMID:27191589

  1. Population success.

    PubMed

    1982-01-01

    "The commitment to population programs is now widespread," says Rafael Salas, Executive Director of the UNFPA, in its report "State of World Population." About 80% of the total population of the developing world live in countries which consider their fertility levels too high and would like them reduced. An important impetus came from the World Conference of 1974. The Plan of Action from the conference projected population growth rates in developing countries of 2.0% by 1985. Today it looks as though this projection will be realized. While in 1969, for example, only 26 developing countries had programs aimed at lowering or maintaining fertility levels, by 1980 there were 59. The International Population Conference, recently announced by the UN for 1984, will, it is hoped, help sustain that momentum. Cuba is the country which has shown the greatest decline in birth rate so far. The birth rate fell 47% between 1965-1970 and 1975-1980. Next came China with a 34% decline in the same period. After these came a group of countries--each with populations of over 10 million--with declines of between 15 and 25%: Chile, Colombia, India, Indonesia, the Republic of Korea, Malaysia and Thailand. Though birth rates have been dropping significantly the decline in mortality rates over recent years has been less than was hoped for. The 1974 conference set 74 years as the target for the world's average expectation of life, to be reached by the year 2000. But the UN now predicts that the developing countries will have only reached 63 or 64 years by then. High infant and child mortality rates, particularly in Africa, are among the major causes. The report identifies the status of women as an important determinant of family size. Evidence from the UNFPA-sponsored World Fertility Survey shows that in general the fertility of women decreases as their income increases. It also indicates that women who have been educated and who work outside the home are likely to have smaller families

  2. AIDS and population "control".

    PubMed

    Piel, G

    1994-02-01

    Many people believe that the AIDS pandemic will end the population explosion, especially in Africa, where population growth is very high and poverty reigns. Africans make up 10 million of all 15 million HIV- infected persons worldwide. Yet, the proposition that AIDS will sole population explosion does not stand up to reason. About 200 million people in Africa will be HIV infected by 2010, but the loss of 200 million people would not slow population growth. The 14th century's Black Death killed more than 50% of the European population, but by 1750 Europe had reached the population size it would have reached without the Black Death. The 200 million people who died violent deaths between the start and end of the two World Wars did not stop world population growth from peaking in 1970 at about 2%. When Malthus made his prediction that human population would crash, the industrial revolution had already helped production outrun population growth. Today all industrial countries are either at or near zero population growth and have completed the demographic transition (from near zero growth in 1600 with high births and death rates and a 25-year life expectancy, to near zero growth in 1990s at low death and birth rates with a 75-year life expectancy). Mass education, sanitation, primary medicine, and the green revolution have already reduced death rates and increased life expectancy in developing countries. Thus, they have entered the first phase of the demographic transition. Some developing countries are in the second phase; birth rate decline For example, in India and China, fertility has fallen from 6 to 4 in India and is at 2.3 in China. The AIDS pandemic is a diversion of physical and human resources from helping developing countries pass through the demographic transition more quickly to achieve sustainable development. This delay is likely to effect a larger maximum population. The industrial revolution has shifted the key to stopping population growth the people

  3. Education Vital Signs: Population.

    ERIC Educational Resources Information Center

    Zakariya, Sally Banks

    1985-01-01

    Population changes and demographics shape the future of public schools. Includes statistics on ethnic makeup of student population, the projected baby boomlet, children of working mothers, households without children, and the aging population. (MD)

  4. Diversity of Poissonian populations.

    PubMed

    Eliazar, Iddo I; Sokolov, Igor M

    2010-01-01

    Populations represented by collections of points scattered randomly on the real line are ubiquitous in science and engineering. The statistical modeling of such populations leads naturally to Poissonian populations-Poisson processes on the real line with a distinguished maximal point. Poissonian populations are infinite objects underlying key issues in statistical physics, probability theory, and random fractals. Due to their infiniteness, measuring the diversity of Poissonian populations depends on the lower-bound cut-off applied. This research characterizes the classes of Poissonian populations whose diversities are invariant with respect to the cut-off level applied and establishes an elemental connection between these classes and extreme-value theory. The measures of diversity considered are variance and dispersion, Simpson's index and inverse participation ratio, Shannon's entropy and Rényi's entropy, and Gini's index.

  5. USING POPULATION MODELS TO EVALUATE RISK IN POPULATION OF BIRDS

    EPA Science Inventory

    Wildlife populations are exposed to varying habitat structure and quality, as well as an array of human-induced environmental stressors. Predicting the consequences to a real population of one perturbation (e.g. a pesticide application) without considering other human activities ...

  6. Population Policy and the Changing Distribution of the U.S. Population--Implications for Teaching Population Geography.

    ERIC Educational Resources Information Center

    Gober, Patricia

    The role of migration and of federal policy in population redistribution should be a central focus in population geography education. Although migration to the Sunbelt and the West has been a pattern since the 1950s, a significant trend has been noted only since the 1970s, when the birth rate dropped so much that natural increase could not…

  7. A POPULATION MEMETICS APPROACH TO CULTURAL EVOLUTION IN CHAFFINCH SONG: DIFFERENTIATION AMONG POPULATIONS.

    PubMed

    Lynch, Alejandro; Baker, Allan J

    1994-04-01

    We investigated cultural evolution in populations of common chaffinches (Fringilla coelebs) in the Atlantic islands (Azores, Madeira, and Canaries) and neighboring continental regions (Morocco and Iberia) by employing a population-memetic approach. To quantify differentiation, we used the concept of a song meme, defined as a single syllable or a series of linked syllables capable of being transmitted. The levels of cultural differentiation are higher among the Canaries populations than among the Azorean ones, even though the islands are on average closer to each other geographically. This is likely the result of reduced levels of migration, lower population sizes, and bottlenecks (possibly during the colonization of these populations) in the Canaries; all these factors produce a smaller effective population size and therefore accentuate the effects of differentiation by random drift. Significant levels of among-population differentiation in the Azores, in spite of substantial levels of migration, attest to the differentiating effects of high mutation rates of memes, which allow the accumulation of new mutants in different populations before migration can disperse them throughout the entire region. © 1994 The Society for the Study of Evolution.

  8. The Growth of Older Inmate Populations: How Population Aging Explains Rising Age at Admission.

    PubMed

    Luallen, Jeremy; Cutler, Christopher

    2017-09-01

    Older inmates are the fastest growing segment of the prison population; however, the reasons for this are not well understood. One explanation is that the general population is aging, driving prison age distributions to change. For this article, we study the role of population aging in prison growth by investigating how the baby boom phenomenon of post-World War II has contributed to the growth of older inmate populations. We identify the impact of population aging using simulation methods that explain prison growth as the combination of criminal justice processes. Overall, we find evidence that population aging has played a significant role in explaining the growth of older inmate populations, in particular among inmates aged between 50 and 64 years, contributing to as much as half of the observed increase in these groups since 2000. This finding stands in contrast to the notion that population aging has little explanatory power in describing the growth of prison populations and implies that older inmate groups are more sensitive to compositional changes in the general population. We argue that prediction-based modeling of prison growth should more seriously consider the impacts and consequences of demographic shifts among older prisoner populations. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Evolution in Stage-Structured Populations

    PubMed Central

    Barfield, Michael; Holt, Robert D.; Gomulkiewicz, Richard

    2016-01-01

    For many organisms, stage is a better predictor of demographic rates than age. Yet no general theoretical framework exists for understanding or predicting evolution in stage-structured populations. Here, we provide a general modeling approach that can be used to predict evolution and demography of stage-structured populations. This advances our ability to understand evolution in stage-structured populations to a level previously available only for populations structured by age. We use this framework to provide the first rigorous proof that Lande’s theorem, which relates adaptive evolution to population growth, applies to stage-classified populations, assuming only normality and that evolution is slow relative to population dynamics. We extend this theorem to allow for different means or variances among stages. Our next major result is the formulation of Price’s theorem, a fundamental law of evolution, for stage-structured populations. In addition, we use data from Trillium grandiflorum to demonstrate how our models can be applied to a real-world population and thereby show their practical potential to generate accurate projections of evolutionary and population dynamics. Finally, we use our framework to compare rates of evolution in age- versus stage-structured populations, which shows how our methods can yield biological insights about evolution in stage-structured populations. PMID:21460563

  10. Population Response to Habitat Fragmentation in a Stream-Dwelling Brook Trout Population

    PubMed Central

    Letcher, Benjamin H.; Nislow, Keith H.; Coombs, Jason A.; O'Donnell, Matthew J.; Dubreuil, Todd L.

    2007-01-01

    Fragmentation can strongly influence population persistence and expression of life-history strategies in spatially-structured populations. In this study, we directly estimated size-specific dispersal, growth, and survival of stream-dwelling brook trout in a stream network with connected and naturally-isolated tributaries. We used multiple-generation, individual-based data to develop and parameterize a size-class and location-based population projection model, allowing us to test effects of fragmentation on population dynamics at local (i.e., subpopulation) and system-wide (i.e., metapopulation) scales, and to identify demographic rates which influence the persistence of isolated and fragmented populations. In the naturally-isolated tributary, persistence was associated with higher early juvenile survival (∼45% greater), shorter generation time (one-half) and strong selection against large body size compared to the open system, resulting in a stage-distribution skewed towards younger, smaller fish. Simulating barriers to upstream migration into two currently-connected tributary populations caused rapid (2–6 generations) local extinction. These local extinctions in turn increased the likelihood of system-wide extinction, as tributaries could no longer function as population sources. Extinction could be prevented in the open system if sufficient immigrants from downstream areas were available, but the influx of individuals necessary to counteract fragmentation effects was high (7–46% of the total population annually). In the absence of sufficient immigration, a demographic change (higher early survival characteristic of the isolated tributary) was also sufficient to rescue the population from fragmentation, suggesting that the observed differences in size distributions between the naturally-isolated and open system may reflect an evolutionary response to isolation. Combined with strong genetic divergence between the isolated tributary and open system, these

  11. Population response to habitat fragmentation in a stream-dwelling brook trout population

    USGS Publications Warehouse

    Letcher, B.H.; Nislow, K.H.; Coombs, J.A.; O'Donnell, M. J.; Dubreuil, T.L.

    2007-01-01

    Fragmentation can strongly influence population persistence and expression of life-history strategies in spatially-structured populations. In this study, we directly estimated size-specific dispersal, growth, and survival of stream-dwelling brook trout in a stream network with connected and naturally-isolated tributaries. We used multiple-generation, individual-based data to develop and parameterize a size-class and location-based population projection model, allowing us to test effects of fragmentation on population dynamics at local (i.e., subpopulation) and system-wide (i.e., metapopulation) scales, and to identify demographic rates which influence the persistence of isolated and fragmented populations. In the naturally-isolated tributary, persistence was associated with higher early juvenile survival (-45% greater), shorter generation time (one-half) and strong selection against large body size compared to the open system, resulting in a stage-distribution skewed towards younger, smaller fish. Simulating barriers to upstream migration into two currently-connected tribuory populations caused rapid (2-6 generations) local extinction. These local extinctions in turn increased the likelihood of system-wide extinction, as tributaries could no longer function as population sources. Extinction could be prevented in the open system if sufficient immigrants from downstream areas were available, but the influx of individuals necessary to counteract fragmentation effects was high (7-46% of the total population annually). In the absence of sufficient immigration, a demographic change (higher early survival characteristic of the isolated tributary) was also sufficient to rescue the population from fragmentation, suggesting that the observed differences in size distributions between the naturally-isolated and open system may reflect an evolutionary response to isolation. Combined with strong genetic divergence between the isolated tributary and open system, these results

  12. Developing STR databases on structured populations: the native South Siberian population versus the Russian population.

    PubMed

    Zhivotovsky, Lev A; Malyarchuk, Boris A; Derenko, Miroslava V; Wozniak, Marcin; Grzybowski, Tomasz

    2009-09-01

    Developing a forensic DNA database on a population that consists of local ethnic groups separated by physical and cultural barriers is questionable as it can be genetically subdivided. On the other side, small sizes of ethnic groups, especially in alpine regions where they are sub-structured further into small villages, prevent collecting a large sample from each ethnic group. For such situations, we suggest to obtain both a total population database on allele frequencies across ethnic groups and a list of theta-values between the groups and the total data. We have genotyped 558 individuals from the native population of South Siberia, consisting of nine ethnic groups, at 17 autosomal STR loci of the kit packages AmpFlSTR SGM Plus i, Cyrillic AmpFlSTR Profiler Plus. The groups differentiate from each other with average theta-values of around 1.1%, and some reach up to three to four percent at certain loci. There exists between-village differentiation as well. Therefore, a database for the population of South Siberia is composed of data on allele frequencies in the pool of ethnic groups and data on theta-values that indicate variation in allele frequencies across the groups. Comparison to additional data on northeastern Asia (the Chukchi and Koryak) shows that differentiation in allele frequencies among small groups that are separated by large geographic distance can be even greater. In contrast, populations of Russians that live in large cities of the European part of Russia are homogeneous in allele frequencies, despite large geographic distance between them, and thus can be described by a database on allele frequencies alone, without any specific information on theta-values.

  13. Multi-population Genomic Relationships for Estimating Current Genetic Variances Within and Genetic Correlations Between Populations.

    PubMed

    Wientjes, Yvonne C J; Bijma, Piter; Vandenplas, Jérémie; Calus, Mario P L

    2017-10-01

    Different methods are available to calculate multi-population genomic relationship matrices. Since those matrices differ in base population, it is anticipated that the method used to calculate genomic relationships affects the estimate of genetic variances, covariances, and correlations. The aim of this article is to define the multi-population genomic relationship matrix to estimate current genetic variances within and genetic correlations between populations. The genomic relationship matrix containing two populations consists of four blocks, one block for population 1, one block for population 2, and two blocks for relationships between the populations. It is known, based on literature, that by using current allele frequencies to calculate genomic relationships within a population, current genetic variances are estimated. In this article, we theoretically derived the properties of the genomic relationship matrix to estimate genetic correlations between populations and validated it using simulations. When the scaling factor of across-population genomic relationships is equal to the product of the square roots of the scaling factors for within-population genomic relationships, the genetic correlation is estimated unbiasedly even though estimated genetic variances do not necessarily refer to the current population. When this property is not met, the correlation based on estimated variances should be multiplied by a correction factor based on the scaling factors. In this study, we present a genomic relationship matrix which directly estimates current genetic variances as well as genetic correlations between populations. Copyright © 2017 by the Genetics Society of America.

  14. Setting population targets for mammals using body mass as a predictor of population persistence.

    PubMed

    Hilbers, Jelle P; Santini, Luca; Visconti, Piero; Schipper, Aafke M; Pinto, Cecilia; Rondinini, Carlo; Huijbregts, Mark A J

    2017-04-01

    Conservation planning and biodiversity assessments need quantitative targets to optimize planning options and assess the adequacy of current species protection. However, targets aiming at persistence require population-specific data, which limit their use in favor of fixed and nonspecific targets, likely leading to unequal distribution of conservation efforts among species. We devised a method to derive equitable population targets; that is, quantitative targets of population size that ensure equal probabilities of persistence across a set of species and that can be easily inferred from species-specific traits. In our method, we used models of population dynamics across a range of life-history traits related to species' body mass to estimate minimum viable population targets. We applied our method to a range of body masses of mammals, from 2 g to 3825 kg. The minimum viable population targets decreased asymptotically with increasing body mass and were on the same order of magnitude as minimum viable population estimates from species- and context-specific studies. Our approach provides a compromise between pragmatic, nonspecific population targets and detailed context-specific estimates of population viability for which only limited data are available. It enables a first estimation of species-specific population targets based on a readily available trait and thus allows setting equitable targets for population persistence in large-scale and multispecies conservation assessments and planning. © 2016 The Authors. Conservation Biology published by Wiley Periodicals, Inc. on behalf of Society for Conservation Biology.

  15. 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.

  16. The Population Tracking Model: A Simple, Scalable Statistical Model for Neural Population Data

    PubMed Central

    O'Donnell, Cian; alves, J. Tiago Gonç; Whiteley, Nick; Portera-Cailliau, Carlos; Sejnowski, Terrence J.

    2017-01-01

    Our understanding of neural population coding has been limited by a lack of analysis methods to characterize spiking data from large populations. The biggest challenge comes from the fact that the number of possible network activity patterns scales exponentially with the number of neurons recorded (∼2Neurons). Here we introduce a new statistical method for characterizing neural population activity that requires semi-independent fitting of only as many parameters as the square of the number of neurons, requiring drastically smaller data sets and minimal computation time. The model works by matching the population rate (the number of neurons synchronously active) and the probability that each individual neuron fires given the population rate. We found that this model can accurately fit synthetic data from up to 1000 neurons. We also found that the model could rapidly decode visual stimuli from neural population data from macaque primary visual cortex about 65 ms after stimulus onset. Finally, we used the model to estimate the entropy of neural population activity in developing mouse somatosensory cortex and, surprisingly, found that it first increases, and then decreases during development. This statistical model opens new options for interrogating neural population data and can bolster the use of modern large-scale in vivo Ca2+ and voltage imaging tools. PMID:27870612

  17. Modeling Exponential Population Growth

    ERIC Educational Resources Information Center

    McCormick, Bonnie

    2009-01-01

    The concept of population growth patterns is a key component of understanding evolution by natural selection and population dynamics in ecosystems. The National Science Education Standards (NSES) include standards related to population growth in sections on biological evolution, interdependence of organisms, and science in personal and social…

  18. Nonbreeding isolation and population-specific migration patterns among three populations of Golden-winged Warblers

    USGS Publications Warehouse

    Kramer, Gunnar R.; Streby, Henry M.; Peterson, Sean M.; Lehman, Justin A.; Buehler, David A.; Wood, Petra B.; McNeil, Darin J.; Larkin, Jeffrey L.; Andersen, David E.

    2017-01-01

    Golden-winged Warblers (Vermivora chrysoptera) are Nearctic–Neotropical migrants experiencing varied regional population trends not fully explained by breeding-grounds factors such as nest success. A lack of detailed information on the nonbreeding distributions, migration routes, or timing of migration among populations hampers our ability to identify population processes outside the breeding period. We used geolocators to track annual movements of 21 Golden-winged Warblers from 3 North American breeding locations experiencing varying population trends to investigate the potential for nonbreeding site factors to influence breeding populations. We used the template-fit method to estimate locations of individual warblers throughout the year. Geolocator-marked warblers exhibited significant isolation among populations during migration and the nonbreeding period. During the nonbreeding period, Golden-winged Warblers from Minnesota, USA (n = 12) occurred in Central America from southern Mexico to central Nicaragua; warblers from Tennessee, USA (n = 7) occurred along the border of northern Colombia and Venezuela; and warblers from Pennsylvania, USA (n = 2) occurred in north-central Venezuela. Warblers travelled at slower rates over more days in fall migration than spring migration. Fall migration routes at the Gulf of Mexico were population-specific, whereas spring routes were more varied and overlapped among populations. Golden-winged Warblers from Pennsylvania migrated 4,000 and 5,000 km yr−1 farther than Tennessee and Minnesota warblers, respectively, and spent almost twice as long migrating in the fall compared to Minnesota warblers. Our results reveal nearly complete temporal and geographic isolation among 3 populations of Golden-winged Warblers throughout the annual cycle, resulting in opportunities for population- and site-specific factors to differentially influence populations outside the breeding period. Our findings highlight the need for monitoring

  19. River mainstem thermal regimes influence population structuring within an Appalachian brook trout population

    USGS Publications Warehouse

    Aunins, Aaron W.; Petty, J. Todd; King, Timothy L.; Schilz, Mariya; Mazik, Patricia M.

    2015-01-01

    Brook trout (Salvelinus fontinalis) often exist as highly differentiated populations, even at small spatial scales, due either to natural or anthropogenic sources of isolation and low rates of dispersal. In this study, we used molecular approaches to describe the unique population structure of brook trout inhabiting the Shavers Fork watershed, located in eastern West Virginia, and contrast it to nearby populations in tributaries of the upper Greenbrier River and North Fork South Branch Potomac Rivers. Bayesian and maximum likelihood clustering methods identified minimal population structuring among 14 collections of brook trout from throughout the mainstem and tributaries of Shavers Fork, highlighting the role of the cold-water mainstem for connectivity and high rates of effective migration among tributaries. In contrast, the Potomac and Greenbrier River collections displayed distinct levels of population differentiation among tributaries, presumably resulting from tributary isolation by warm-water mainstems. Our results highlight the importance of protecting and restoring cold-water mainstem habitats as part of region-wide brook trout conservation efforts. In addition, our results from Shavers Fork provide a contrast to previous genetic studies that characterize Appalachian brook trout as fragmented isolates rather than well-mixed populations. Additional study is needed to determine whether the existence of brook trout as genetically similar populations among tributaries is truly unique and whether connectivity among brook trout populations can potentially be restored within other central Appalachian watersheds.

  20. America's Families and Living Arrangements: 2003. Population Characteristics. Current Population Reports. P20-553

    ERIC Educational Resources Information Center

    Fields, Jason

    2004-01-01

    The data in this report is from the Annual Social and Economic Supplement (ASEC) to the 2003 Current Population Survey (CPS). The population represented (the population universe) in the ASEC is the civilian non institutionalized population living in the United States. Members of the Armed Forces living off post or with their families on post are…

  1. Population: A Lively Introduction.

    ERIC Educational Resources Information Center

    McFalls, Joseph A., Jr.

    1991-01-01

    The study of demography must begin with an understanding of the three sources of population changes: fertility, mortality, and migration. This paper leads prospective demographers--or anyone interested in population--through the dynamics of these three variables, introducing them to the forces that cause populations to grow or decline, and that…

  2. Vulnerable populations in healthcare.

    PubMed

    Waisel, David B

    2013-04-01

    This review is designed to update readers on recent discussions and research regarding vulnerable populations in medicine, including patients who are socioeconomically disadvantaged, queer, in prison or labeled with a stigmatizing complex medical disease. Recent studies have more closely examined the effects of being part of a vulnerable population. Greater societal income inequality impacts those at the lower end of the income curve by increasing mortality and heightening the importance of individual personal situations. Recommendations from an extensive WHO report on the social determinants of health may affect social policy and use of public resources in Europe. Clinicians are undereducated about the lives and concerns of vulnerable populations, including LGBTQI persons, immigrants, physicians, prisoners, and families of patients with diseases considered 'incompatible with life'. Greater understanding of the cause of the health effects of being socioeconomically disadvantaged or being a member of a vulnerable population may be the first steps toward specific policy recommendations. Professional medical organizations and advocacy groups should raise awareness, provide education, publish guidelines and define the goals for the medical care for certain vulnerable populations.Vulnerable populations are at risk for disparate healthcare access and outcomes because of economic, cultural, ethnic or health characteristics. Vulnerable populations include patients who are racial or ethnic minorities, children, elderly, socioeconomically disadvantaged, underinsured or those with certain medical conditions. Members of vulnerable populations often have health conditions that are exacerbated by unnecessarily inadequate healthcare.

  3. Analysis of Population Substructure in Two Sympatric Populations of Gran Chaco, Argentina

    PubMed Central

    Sevini, Federica; Yao, Daniele Yang; Lomartire, Laura; Barbieri, Annalaura; Vianello, Dario; Ferri, Gianmarco; Moretti, Edgardo; Dasso, Maria Cristina; Garagnani, Paolo; Pettener, Davide; Franceschi, Claudio; Luiselli, Donata; Franceschi, Zelda Alice

    2013-01-01

    Sub-population structure and intricate kinship dynamics might introduce biases in molecular anthropology studies and could invalidate the efforts to understand diseases in highly admixed populations. In order to clarify the previously observed distribution pattern and morbidity of Chagas disease in Gran Chaco, Argentina, we studied two populations (Wichí and Criollos) recruited following an innovative bio-cultural model considering their complex cultural interactions. By reconstructing the genetic background and the structure of these two culturally different populations, the pattern of admixture, the correspondence between genealogical and genetic relationships, this integrated perspective had the power to validate data and to link the gap usually relying on a singular discipline. Although Wichí and Criollos share the same area, these sympatric populations are differentiated from the genetic point of view as revealed by Non Recombinant Y Chromosome genotyping resulting in significantly high Fst values and in a lower genetic variability in the Wichí population. Surprisingly, the Amerindian and the European components emerged with comparable amounts (20%) among Criollos and Wichí respectively. The detailed analysis of mitochondrial DNA showed that the two populations have as much as 87% of private haplotypes. Moreover, from the maternal perspective, despite a common Amerindian origin, an Andean and an Amazonian component emerged in Criollos and in Wichí respectively. Our approach allowed us to highlight that quite frequently there is a discrepancy between self-reported and genetic kinship. Indeed, if self-reported identity and kinship are usually utilized in population genetics as a reliable proxy for genetic identity and parental relationship, in our model populations appear to be the result not only and not simply of the genetic background but also of complex cultural determinants. This integrated approach paves the way to a rigorous reconstruction of

  4. NASA Orbital Debris Baseline Populations

    NASA Technical Reports Server (NTRS)

    Krisko, Paula H.; Vavrin, A. B.

    2013-01-01

    The NASA Orbital Debris Program Office has created high fidelity populations of the debris environment. The populations include objects of 1 cm and larger in Low Earth Orbit through Geosynchronous Transfer Orbit. They were designed for the purpose of assisting debris researchers and sensor developers in planning and testing. This environment is derived directly from the newest ORDEM model populations which include a background derived from LEGEND, as well as specific events such as the Chinese ASAT test, the Iridium 33/Cosmos 2251 accidental collision, the RORSAT sodium-potassium droplet releases, and other miscellaneous events. It is the most realistic ODPO debris population to date. In this paper we present the populations in chart form. We describe derivations of the background population and the specific populations added on. We validate our 1 cm and larger Low Earth Orbit population against SSN, Haystack, and HAX radar measurements.

  5. U.S. population policy.

    PubMed

    Piotrow, P T

    1993-06-01

    Some of the history and special features of the US population assistance program administered by USAID are recounted. Future predictions are also made for funding and new directions for the US population assistance program and environmental issues. The topics addressed were part of a talk given in 1992 at a meeting of the Council on Population Education held in Tokyo. Credit is given to Japan for its contribution to family planning (FP) efforts by setting an example of reducing population size within a decade and providing financial support internationally. Japan's example so impressed General William H. Draper, Jr. that he worked for the establishment of the USAID and the UN Population Fund, and funding for the International Planned Parenthood Federation. He encouraged Japanese officials to provide support for international population and (FP) programs. Currently, the US provides $350 million in population assistance. Encouragement was given for Japan to increase its international commitment of $80 million and to contribute to the Johns Hopkins University William H. Draper, Jr., fellowship fund for graduate students from developing countries to study modern health communication. The special features of the US population assistance program were identified as follows: 1) high funding levels, 2) availability of FP services, 3) adequate contraceptive supplies, 4) availability of professional population staff, and 5) an emphasis on data and evaluation. The single most important element of the USAID program is the reliance on private, nongovernmental organizations (NGOs), which can establish flexible, independent, innovative and cost- effective programs. Predictions for the future were that the US Congress would expand overseas population assistance. Domestic policy will have priority, and the future will depend on who occupies the key policy positions at the State Department and USAID. THere will be more emphasis on free political elections, on humanitarian issues, and

  6. Having quality population.

    PubMed

    Ramos, F V

    1993-06-01

    This speech was delivered during Population and Development Week in the Philippines. Attention was drawn to population statistics: an annual growth rate of 2.3%, density of 202 persons/sq km, and an expected population of 75 million by the year 2000. Coupled with rapid population growth is the uneven distribution of wealth: the top 20% have over 50% of the total income and the lowest 20% have only 5% of the income. In such a social situation, it is women and children who are the most vulnerable. In cities, unemployment is high due to population growth and the migration of the rural poor. The rural poor living in areas of declining resources also move onto marginal uplands, which adds pressure to the already fragile ecology. Everyone must accept that the nation's problems are due to overpopulation. The government's development plans aim for sustainable growth, poverty alleviation, reduction in equality, generation of job opportunities, and achievement of social justice. People in government are determined to lead the Philippines toward a higher standard comparable with other dynamic Asian neighbors. The strategy is empowerment of the people. THe value is in the welfare of individuals and their families and the welfare of the nation. Couples have the right to manage their family size voluntarily and responsibly. The government's role is to provide adequate information on family planning in accordance with individual's religious convictions. Policies will also be directed to improved access to quality education, child survival, and maternal health, employment opportunities, and access and control over resources for people. There must be fuller participation of women in development. Support for the government's population program is sought from government officials, the private sector, and nongovernmental organizations. All provincial governors, city and municipal mayors, and all local executives will be directed to formulate population plans and to provide family

  7. Teaching about Population Growth.

    ERIC Educational Resources Information Center

    Otero, George G., Jr., Comp.

    This teaching guide contains 20 activities on population growth for students in grades 6-12. The purpose is to help students gain the skills, knowledge, and understanding of population dynamics so that they can make rational decisions and take responsible action regarding population matters and public policy. Activities are organized around the…

  8. Controlling Population with Pollution

    ERIC Educational Resources Information Center

    Browne, Joseph

    2010-01-01

    Population models are often discussed in algebra, calculus, and differential equations courses. In this article we will use the human population of the world as our application. After quick looks at two common models we'll investigate more deeply a model which incorporates the negative effect that accumulated pollution may have on population.

  9. Parallel grid population

    DOEpatents

    Wald, Ingo; Ize, Santiago

    2015-07-28

    Parallel population of a grid with a plurality of objects using a plurality of processors. One example embodiment is a method for parallel population of a grid with a plurality of objects using a plurality of processors. The method includes a first act of dividing a grid into n distinct grid portions, where n is the number of processors available for populating the grid. The method also includes acts of dividing a plurality of objects into n distinct sets of objects, assigning a distinct set of objects to each processor such that each processor determines by which distinct grid portion(s) each object in its distinct set of objects is at least partially bounded, and assigning a distinct grid portion to each processor such that each processor populates its distinct grid portion with any objects that were previously determined to be at least partially bounded by its distinct grid portion.

  10. Reevaluating Old Stellar Populations

    NASA Astrophysics Data System (ADS)

    Stanway, E. R.; Eldridge, J. J.

    2018-05-01

    Determining the properties of old stellar populations (those with age >1 Gyr) has long involved the comparison of their integrated light, either in the form of photometry or spectroscopic indexes, with empirical or synthetic templates. Here we reevaluate the properties of old stellar populations using a new set of stellar population synthesis models, designed to incorporate the effects of binary stellar evolution pathways as a function of stellar mass and age. We find that single-aged stellar population models incorporating binary stars, as well as new stellar evolution and atmosphere models, can reproduce the colours and spectral indices observed in both globular clusters and quiescent galaxies. The best fitting model populations are often younger than those derived from older spectral synthesis models, and may also lie at slightly higher metallicities.

  11. Perspectives on population growth.

    PubMed

    1996-09-01

    Assume that everyone has the same information on population growth. There are many different opinions on what that information means and what should be done about it. Some people worry about current rates of growth, especially in the context of growing per capita consumption, and believe that all reasonable steps should be taken to reduce rates and stabilize population size. Others believe that growing populations can be accommodated by reducing consumption in rich countries, that technological progress will supply the new resources needed, that the development needed to support a larger population can be sustained, that large population size fosters prosperity, or that birth rates are falling and current growth is just temporary. These are all valid positions worthy of at least debate. Interest groups commonly acknowledgement population growth as a significant issue, but offer no response to it. Sometimes the issue goes unrecognized because it conflicts with a more highly valued personal agenda item. Finally, some responses come from confusion and anger rather than reasoning or self-interest. The proponents of these latter arguments bring nothing constructive to the debate.

  12. Populations, Teacher's Guide.

    ERIC Educational Resources Information Center

    California Univ., Berkeley. Science Curriculum Improvement Study.

    The Science Curriculum Improvement Study has developed this teacher's guide to "Populations," the third part of a six-unit life science curriculum sequence. The six basic units, emphasizing organism-environment interactions, are organisms, life cycles, populations, environments, communities, and ecosystems; and they make use of…

  13. World Population Crisis.

    ERIC Educational Resources Information Center

    Ehrlich, Paul R.; Ehrlich, Anne H.

    1986-01-01

    Rapid population growth, rising competition for resources, and increasing environmental deterioration are intertwined factors in the human predicament that feed political tensions and conflicts of the late twentieth century. Outlines dimensions of this predicament (including data on population, growth, military spending, quality of life, and…

  14. Population structure and genetic diversity in natural populations of Theobroma speciosum Willd. Ex Spreng (Malvaceae).

    PubMed

    Giustina, L D; Luz, L N; Vieira, F S; Rossi, F S; Soares-Lopes, C R A; Pereira, T N S; Rossi, A A B

    2014-02-14

    The genus Theobroma found in the Amazon region is composed of 22 species, including Theobroma speciosum, better known as cacauí. These species are constantly threatened by forest fragmentation caused by human activities and require conservation strategies and management aimed at preserving them in their natural environments. The main objective of this study was to analyze the population structure and genetic diversity within and between natural populations of T. speciosum by using ISSR molecular markers to understand the population structure of the species. Four natural populations belonging to the Amazon rainforest (BAC, CRO, FLA, and PNA), located in the State of Mato Grosso, were selected. Amplification reactions were performed using 15 ISSR primers. A total of 101 loci were found, of which 54.46% were polymorphic at the species level. The BAC population showed higher genetic diversity (H=0.095 and I=0.144) and higher percentage of polymorphism (28.71%). The populations showed an FST value of 0.604, indicating marked genetic differentiation. The highest genetic variation was found between populations. Gene flow was low between populations, indicating genetic isolation between populations.

  15. Linkage disequilibrium and population structure in wild and domesticated populations of Phaseolus vulgaris L.

    PubMed Central

    Rossi, Monica; Bitocchi, Elena; Bellucci, Elisa; Nanni, Laura; Rau, Domenico; Attene, Giovanna; Papa, Roberto

    2009-01-01

    Together with the knowledge of the population structure, a critical aspect for the planning of association and/or population genomics studies is the level of linkage disequilibrium (LD) that characterizes the species and the population used for such an analysis. We have analyzed the population structure and LD in wild and domesticated populations of Phaseolus vulgaris L. using amplified fragment length polymorphism markers, most of which were genetically mapped in two recombinant inbred populations. Our results reflect the previous knowledge of the occurrence of two major wild gene pools of P. vulgaris, from which two independent domestication events originated, one in the Andes and one in Mesoamerica. The high level of LD in the whole sample was mostly due to the gene pool structure, with a much higher LD in domesticated compared to wild populations. In relation to association studies, our results also suggest that whole-genome-scan approaches are feasible in the common bean. Interestingly, an excess of inter-chromosomal LD was found in the domesticated populations, which suggests an important role for epistatic selection during domestication. Moreover, our results indicate the occurrence of a strong bottleneck in the Andean wild population before domestication, suggesting a Mesoamerican origin of P. vulgaris. Finally, our data support the occurrence of a single domestication event in Mesoamerica, and the same scenario in the Andes. PMID:25567895

  16. Implementation of China's population policy.

    PubMed

    Qian, X Z

    1983-05-01

    On July 1, 1982 China's 3rd national population census reported the population of the 29 provinces, municipalities, and autonomous regions on the mainland at 1,008,175,288, showing a net increase of 460,000,000 or 84% over the 548,000,000 recorded at the end of 1949. At this time China's population is about 1/4 of the world. Its population policy must conform to her national conditions and will be successful only to the extent that it does so. Discussion focuses on the main features of China's population policy. In 1953 the State Council instructed the Ministry of Health to support birth control by providing contraceptives. It also ratified provisions concerning contraception and induced abortions. In 1962 the State Council issued "Instructions on Conscientious Advocacy of Family Planning." China not only advocates and publicized family planning but also takes specific measures. Special administrative organizations were established in 1964 to oversee scientific research, production, and supply of contraceptives and to provide couples of childbearing age with free contraceptives. An all round attack on family planning work in 1966 led to unchecked childbirth resulting in rapid population growth. In 1971 Premier Zhou Enlai reiterated the importance of population control in 1971 and asked that it be incorporated into the 4th Five Year Plan for the development of the national economy. Family planning was incorporated into the Constitution in 1978. China's 20 years of experiences with family planning suggest that a country's population policy becomes effective only with repeated efforts. The 10-year period of turmoil undermined the enforcement of the population policy. Recently the State Family Planning Commission organized a nationwide fertility survey which indicated tremendous successes for China's population control drive. The total fertility rate dropped from 5.29 in the 1950s to 2.63 in the 1980s. The population census shows that the momentum of China's population

  17. Estimating Kinship in Admixed Populations

    PubMed Central

    Thornton, Timothy; Tang, Hua; Hoffmann, Thomas J.; Ochs-Balcom, Heather M.; Caan, Bette J.; Risch, Neil

    2012-01-01

    Genome-wide association studies (GWASs) are commonly used for the mapping of genetic loci that influence complex traits. A problem that is often encountered in both population-based and family-based GWASs is that of identifying cryptic relatedness and population stratification because it is well known that failure to appropriately account for both pedigree and population structure can lead to spurious association. A number of methods have been proposed for identifying relatives in samples from homogeneous populations. A strong assumption of population homogeneity, however, is often untenable, and many GWASs include samples from structured populations. Here, we consider the problem of estimating relatedness in structured populations with admixed ancestry. We propose a method, REAP (relatedness estimation in admixed populations), for robust estimation of identity by descent (IBD)-sharing probabilities and kinship coefficients in admixed populations. REAP appropriately accounts for population structure and ancestry-related assortative mating by using individual-specific allele frequencies at SNPs that are calculated on the basis of ancestry derived from whole-genome analysis. In simulation studies with related individuals and admixture from highly divergent populations, we demonstrate that REAP gives accurate IBD-sharing probabilities and kinship coefficients. We apply REAP to the Mexican Americans in Los Angeles, California (MXL) population sample of release 3 of phase III of the International Haplotype Map Project; in this sample, we identify third- and fourth-degree relatives who have not previously been reported. We also apply REAP to the African American and Hispanic samples from the Women's Health Initiative SNP Health Association Resource (WHI-SHARe) study, in which hundreds of pairs of cryptically related individuals have been identified. PMID:22748210

  18. Towards a Population Dynamics Theory for Evolutionary Computing: Learning from Biological Population Dynamics in Nature

    NASA Astrophysics Data System (ADS)

    Ma, Zhanshan (Sam)

    In evolutionary computing (EC), population size is one of the critical parameters that a researcher has to deal with. Hence, it was no surprise that the pioneers of EC, such as De Jong (1975) and Holland (1975), had already studied the population sizing from the very beginning of EC. What is perhaps surprising is that more than three decades later, we still largely depend on the experience or ad-hoc trial-and-error approach to set the population size. For example, in a recent monograph, Eiben and Smith (2003) indicated: "In almost all EC applications, the population size is constant and does not change during the evolutionary search." Despite enormous research on this issue in recent years, we still lack a well accepted theory for population sizing. In this paper, I propose to develop a population dynamics theory forEC with the inspiration from the population dynamics theory of biological populations in nature. Essentially, the EC population is considered as a dynamic system over time (generations) and space (search space or fitness landscape), similar to the spatial and temporal dynamics of biological populations in nature. With this conceptual mapping, I propose to 'transplant' the biological population dynamics theory to EC via three steps: (i) experimentally test the feasibility—whether or not emulating natural population dynamics improves the EC performance; (ii) comparatively study the underlying mechanisms—why there are improvements, primarily via statistical modeling analysis; (iii) conduct theoretical analysis with theoretical models such as percolation theory and extended evolutionary game theory that are generally applicable to both EC and natural populations. This article is a summary of a series of studies we have performed to achieve the general goal [27][30]-[32]. In the following, I start with an extremely brief introduction on the theory and models of natural population dynamics (Sections 1 & 2). In Sections 4 to 6, I briefly discuss three

  19. Stochastic population dynamics in populations of western terrestrial garter snakes with divergent life histories

    USGS Publications Warehouse

    Miller, David A.; Clark, W.R.; Arnold, S.J.; Bronikowski, A.M.

    2011-01-01

    Comparative evaluations of population dynamics in species with temporal and spatial variation in life-history traits are rare because they require long-term demographic time series from multiple populations. We present such an analysis using demographic data collected during the interval 1978-1996 for six populations of western terrestrial garter snakes (Thamnophis elegans) from two evolutionarily divergent ecotypes. Three replicate populations from a slow-living ecotype, found in mountain meadows of northeastern California, were characterized by individuals that develop slowly, mature late, reproduce infrequently with small reproductive effort, and live longer than individuals of three populations of a fast-living ecotype found at lakeshore locales. We constructed matrix population models for each of the populations based on 8-13 years of data per population and analyzed both deterministic dynamics based on mean annual vital rates and stochastic dynamics incorporating annual variation in vital rates. (1) Contributions of highly variable vital rates to fitness (??s) were buffered against the negative effects of stochastic variation, and this relationship was consistent with differences between the meadow (M-slow) and lakeshore (L-fast) ecotypes. (2) Annual variation in the proportion of gravid females had the greatest negative effect among all vital rates on ?? s. The magnitude of variation in the proportion of gravid females and its effect on ??s was greater in M-slow than L-fast populations. (3) Variation in the proportion of gravid females, in turn, depended on annual variation in prey availability, and its effect on ??s was 4- 23 times greater in M-slow than L-fast populations. In addition to differences in stochastic dynamics between ecotypes, we also found higher mean mortality rates across all age classes in the L-fast populations. Our results suggest that both deterministic and stochastic selective forces have affected the evolution of divergent life

  20. Stochastic population dynamics in populations of western terrestrial garter snakes with divergent life histories.

    PubMed

    Miller, David A; Clark, William R; Arnold, Stevan J; Bronikowski, Anne M

    2011-08-01

    Comparative evaluations of population dynamics in species with temporal and spatial variation in life-history traits are rare because they require long-term demographic time series from multiple populations. We present such an analysis using demographic data collected during the interval 1978-1996 for six populations of western terrestrial garter snakes (Thamnophis elegans) from two evolutionarily divergent ecotypes. Three replicate populations from a slow-living ecotype, found in mountain meadows of northeastern California, were characterized by individuals that develop slowly, mature late, reproduce infrequently with small reproductive effort, and live longer than individuals of three populations of a fast-living ecotype found at lakeshore locales. We constructed matrix population models for each of the populations based on 8-13 years of data per population and analyzed both deterministic dynamics based on mean annual vital rates and stochastic dynamics incorporating annual variation in vital rates. (1) Contributions of highly variable vital rates to fitness (lambda(s)) were buffered against the negative effects of stochastic variation, and this relationship was consistent with differences between the meadow (M-slow) and lakeshore (L-fast) ecotypes. (2) Annual variation in the proportion of gravid females had the greatest negative effect among all vital rates on lambda(s). The magnitude of variation in the proportion of gravid females and its effect on lambda(s) was greater in M-slow than L-fast populations. (3) Variation in the proportion of gravid females, in turn, depended on annual variation in prey availability, and its effect on lambda(s) was 4 23 times greater in M-slow than L-fast populations. In addition to differences in stochastic dynamics between ecotypes, we also found higher mean mortality rates across all age classes in the L-fast populations. Our results suggest that both deterministic and stochastic selective forces have affected the evolution of

  1. Mitochondrial population genomic analyses reveal population structure and demography of Indian Plasmodium falciparum.

    PubMed

    Tyagi, Suchi; Das, Aparup

    2015-09-01

    Inference on the genetic diversity of Plasmodium falciparum populations could help in better management of malaria. A very recent study with mitochondrial (mt) genomes in global P. falciparum had revealed interesting evolutionary genetic patterns of Indian isolates in comparison to global ones. However, no population genetic study using the whole mt genome sequences of P. falciparum isolates collected in the entire distribution range in India has yet been performed. We herewith have analyzed 85 whole mt genomes (48 already published and 37 entirely new) sampled from eight differentially endemic Indian locations to estimate genetic diversity and infer population structure and historical demography of Indian P. falciparum. We found 19 novel Indian-specific Single Nucleotide Polymorphisms (SNPs) and 22 novel haplotypes segregating in Indian P. falciparum. Accordingly, high haplotype and nucleotide diversities were detected in Indian P. falciparum in comparison to many other global isolates. Indian P. falciparum populations were found to be moderately sub-structured with four different genetic clusters. Interestingly, group of local populations aggregate to form each cluster; while samples from Jharkhand and Odisha formed a single cluster, P. falciparum isolates from Asom formed an independent one. Similarly, Surat, Bilaspur and Betul formed a single cluster and Goa and Mangalore formed another. Interestingly, P. falciparum isolates from the two later populations were significantly genetically differentiated from isolates collected in other six Indian locations. Signature of historical population expansion was evident in five population samples, and the onset of expansion event was found to be very similar to African P. falciparum. In agreement with the previous finding, the estimated Time to Most Recent Common Ancestor (TMRCA) and the effective population size were high in Indian P. falciparum. All these genetic features of Indian P. falciparum with high mt genome

  2. Regional Population Dynamics

    Treesearch

    Andrew Birt

    2011-01-01

    The population dynamics of the southern pine beetle (SPB) exhibit characteristic fluctuations between relatively long endemic and shorter outbreak periods. Populations exhibit complex and hierarchical spatial structure with beetles and larvae aggregating within individual trees, infestations with multiple infested trees, and regional outbreaks that comprise a large...

  3. Population estimates of Nearctic shorebirds

    USGS Publications Warehouse

    Morrison, R.I.G.; Gill, Robert E.; Harrington, B.A.; Skagen, S.K.; Page, G.W.; Gratto-Trevor, C. L.; Haig, S.M.

    2000-01-01

    Estimates are presented for the population sizes of 53 species of Nearctic shorebirds occurring regularly in North America, plus four species that breed occasionally. Shorebird population sizes were derived from data obtained by a variety of methods from breeding, migration and wintering areas, and formal assessments of accuracy of counts or estimates are rarely available. Accurate estimates exist only for a few species that have been the subject of detailed investigation, and the likely accuracy of most estimates is considered poor or low. Population estimates range from a few tens to several millions. Overall, population estimates most commonly fell in the range of hundreds of thousands, particularly the low hundreds of thousands; estimated population sizes for large shorebird species currently all fall below 500,000. Population size was inversely related to size (mass) of the species, with a statistically significant negative regression between log (population size) and log (mass). Two outlying groups were evident on the regression graph: one, with populations lower than predicted, included species considered either to be "at risk" or particularly hard to count, and a second, with populations higher than predicted, included two species that are hunted. Population estimates are an integral part of conservation plans being developed for shorebirds in the United States and Canada, and may be used to identify areas of key international and regional importance.

  4. 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

  5. Cost-effectiveness and population outcomes of general population screening for hepatitis C.

    PubMed

    Coffin, Phillip O; Scott, John D; Golden, Matthew R; Sullivan, Sean D

    2012-05-01

    Current US guidelines recommend limiting hepatitis C virus (HCV) screening to high-risk individuals, and 50%-75% of infected persons remain unaware of their status. To estimate the cost-effectiveness and population-level impact of adding one-time HCV screening of US population aged 20-69 years to current guidelines, we developed a decision analytic model for the screening intervention and Markov model with annual transitions to estimate natural history. Subanalyses included protease inhibitor therapy and screening those at highest risk of infection (birth year 1945-1965). We relied on published literature and took a lifetime, societal perspective. Compared to current guidelines, incremental cost per quality-adjusted life year gained (ICER) was $7900 for general population screening and $4200 for screening by birth year, which dominated general population screening if cost, clinician uptake, and median age of diagnoses were assumed equivalent. General population screening remained cost-effective in all one-way sensitivity analyses, 30 000 Monte Carlo simulations, and scenarios in which background mortality was doubled, all genotype 1 patients were treated with protease inhibitors, and most parameters were set unfavorable to increased screening. ICER was lowest if screening was applied to a population with liver fibrosis similar to 2010 estimates. Approximately 1% of liver-related deaths would be averted per 15% of the general population screened; the impact would be greater with improved referral, treatment uptake, and cure. Broader screening for HCV would likely be cost-effective, but significantly reducing HCV-related morbidity and mortality would also require improved rates of referral, treatment, and cure.

  6. Mentoring Special Populations

    ERIC Educational Resources Information Center

    Whitfield, Keith E.; Edwards, Christopher L.

    2011-01-01

    Mentorship is critical for career development. Members of special populations are at increased risk of information shortfalls and advice that is not framed with cultural sensitivity. Special knowledge and skills are needed to successfully mentor members of ethnic minority and other special populations. Midlevel and senior scientists need…

  7. [Population trends in Albania].

    PubMed

    Sivignon, M

    1983-01-01

    Recent demographic trends in Albania are reviewed. The author notes that rapid population growth persists due to continuing fertility, although the fertility rate has begun to decline during the past 20 years. Controls placed on internal migration have succeeded in restricting the growth of the urban population and have contributed to the sustained growth of the population in rural areas. (summary in ENG)

  8. Modeling sandhill crane population dynamics

    USGS Publications Warehouse

    Johnson, D.H.

    1979-01-01

    The impact of sport hunting on the Central Flyway population of sandhill cranes (Grus canadensis) has been a subject of controversy for several years. A recent study (Buller 1979) presented new and important information on sandhill crane population dynamics. The present report is intended to incorporate that and other information into a mathematical model for the purpose of assessing the long-range impact of hunting on the population of sandhill cranes.The model is a simple deterministic system that embodies density-dependent rates of survival and recruitment. The model employs four kinds of data: (1) spring population size of sandhill cranes, estimated from aerial surveys to be between 250,000 and 400,000 birds; (2) age composition in fall, estimated for 1974-76 to be 11.3% young; (3) annual harvest of cranes, estimated from a variety of sources to be about 5 to 7% of the spring population; and (4) age composition of harvested cranes, which was difficult to estimate but suggests that immatures were 2 to 4 times as vulnerable to hunting as adults.Because the true nature of sandhill crane population dynamics remains so poorly understood, it was necessary to try numerous (768 in all) combinations of survival and recruitment functions, and focus on the relatively few (37) that yielded population sizes and age structures comparable to those extant in the real population. Hunting was then applied to those simulated populations. In all combinations, hunting resulted in a lower asymptotic crane population, the decline ranging from 5 to 54%. The median decline was 22%, which suggests that a hunted sandhill crane population might be about three-fourths as large as it would be if left unhunted. Results apply to the aggregate of the three subspecies in the Central Flyway; individual subspecies or populations could be affected to a greater or lesser degree.

  9. Rapid evolution leads to differential population dynamics and top-down control in resurrected Daphnia populations.

    PubMed

    Goitom, Eyerusalem; Kilsdonk, Laurens J; Brans, Kristien; Jansen, Mieke; Lemmens, Pieter; De Meester, Luc

    2018-01-01

    There is growing evidence of rapid genetic adaptation of natural populations to environmental change, opening the perspective that evolutionary trait change may subsequently impact ecological processes such as population dynamics, community composition, and ecosystem functioning. To study such eco-evolutionary feedbacks in natural populations, however, requires samples across time. Here, we capitalize on a resurrection ecology study that documented rapid and adaptive evolution in a natural population of the water flea Daphnia magna in response to strong changes in predation pressure by fish, and carry out a follow-up mesocosm experiment to test whether the observed genetic changes influence population dynamics and top-down control of phytoplankton. We inoculated populations of the water flea D. magna derived from three time periods of the same natural population known to have genetically adapted to changes in predation pressure in replicate mesocosms and monitored both Daphnia population densities and phytoplankton biomass in the presence and absence of fish. Our results revealed differences in population dynamics and top-down control of algae between mesocosms harboring populations from the time period before, during, and after a peak in fish predation pressure caused by human fish stocking. The differences, however, deviated from our a priori expectations. An S-map approach on time series revealed that the interactions between adults and juveniles strongly impacted the dynamics of populations and their top-down control on algae in the mesocosms, and that the strength of these interactions was modulated by rapid evolution as it occurred in nature. Our study provides an example of an evolutionary response that fundamentally alters the processes structuring population dynamics and impacts ecosystem features.

  10. A population memetics approach to cultural evolution in chaffinch song: meme diversity within populations.

    PubMed

    Lynch, A; Baker, A J

    1993-04-01

    We investigated cultural evolution in populations of common chaffinches (Fringilla coelebs) in the Atlantic islands (Azores, Madeira, Canaries) and neighboring continental regions (Morocco, Iberia) by employing a population memetics approach. To quantify variability within populations, we used the concept of a song meme, defined as a single syllable or a series of linked syllables capable of being transmitted. The frequency distribution of memes within populations generally fit a neutral model in which there is an equilibrium between mutation, migration, and drift, which suggests that memes are functionally equivalent. The diversity of memes of single syllables is significantly greater in the Azores compared to all other regions, consistent with higher population densities of chaffinches there. On the other hand, memes of two to five syllables have greater diversity in Atlantic island and Moroccan populations compared to their Iberian counterparts. This higher diversity emanates from a looser syntax and increased recombination in songs, presumably because of relaxed selection for distinctive songs in these peripheral and depauperate avifaunas. We urge comparative population memetic studies of other species of songbirds and predict that they will lead to a formulation of a general theory for the cultural evolution of bird song analogous to population genetics theory for biological traits.

  11. Evaluating models of population process in a threatened population of Steller’s eiders: A retrospective approach

    USGS Publications Warehouse

    Dunham, Kylee; Grand, James B.

    2016-10-11

    The Alaskan breeding population of Steller’s eiders (Polysticta stelleri) was listed as threatened under the Endangered Species Act in 1997 in response to perceived declines in abundance throughout their breeding and nesting range. Aerial surveys suggest the breeding population is small and highly variable in number, with zero birds counted in 5 of the last 25 years. Research was conducted to evaluate competing population process models of Alaskan-breeding Steller’s eiders through comparison of model projections to aerial survey data. To evaluate model efficacy and estimate demographic parameters, a Bayesian state-space modeling framework was used and each model was fit to counts from the annual aerial surveys, using sequential importance sampling and resampling. The results strongly support that the Alaskan breeding population experiences population level nonbreeding events and is open to exchange with the larger Russian-Pacific breeding population. Current recovery criteria for the Alaskan breeding population rely heavily on the ability to estimate population viability. The results of this investigation provide an informative model of the population process that can be used to examine future population states and assess the population in terms of the current recovery and reclassification criteria.

  12. Yonsei Evolutionary Population Synthesis (YEPS). II. Spectro-photometric Evolution of Helium-enhanced Stellar Populations

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

    Chung, Chul; Yoon, Suk-Jin; Lee, Young-Wook, E-mail: chulchung@yonsei.ac.kr, E-mail: sjyoon0691@yonsei.ac.kr

    The discovery of multiple stellar populations in Milky Way globular clusters (GCs) has stimulated various follow-up studies on helium-enhanced stellar populations. Here we present the evolutionary population synthesis models for the spectro-photometric evolution of simple stellar populations (SSPs) with varying initial helium abundance ( Y {sub ini}). We show that Y {sub ini} brings about dramatic changes in spectro-photometric properties of SSPs. Like the normal-helium SSPs, the integrated spectro-photometric evolution of helium-enhanced SSPs is also dependent on metallicity and age for a given Y {sub ini}. We discuss the implications and prospects for the helium-enhanced populations in relation to themore » second-generation populations found in the Milky Way GCs. All of the models are available at http://web.yonsei.ac.kr/cosmic/data/YEPS.htm.« less

  13. A general methodology for population analysis

    NASA Astrophysics Data System (ADS)

    Lazov, Petar; Lazov, Igor

    2014-12-01

    For a given population with N - current and M - maximum number of entities, modeled by a Birth-Death Process (BDP) with size M+1, we introduce utilization parameter ρ, ratio of the primary birth and death rates in that BDP, which, physically, determines (equilibrium) macrostates of the population, and information parameter ν, which has an interpretation as population information stiffness. The BDP, modeling the population, is in the state n, n=0,1,…,M, if N=n. In presence of these two key metrics, applying continuity law, equilibrium balance equations concerning the probability distribution pn, n=0,1,…,M, of the quantity N, pn=Prob{N=n}, in equilibrium, and conservation law, and relying on the fundamental concepts population information and population entropy, we develop a general methodology for population analysis; thereto, by definition, population entropy is uncertainty, related to the population. In this approach, what is its essential contribution, the population information consists of three basic parts: elastic (Hooke's) or absorption/emission part, synchronization or inelastic part and null part; the first two parts, which determine uniquely the null part (the null part connects them), are the two basic components of the Information Spectrum of the population. Population entropy, as mean value of population information, follows this division of the information. A given population can function in information elastic, antielastic and inelastic regime. In an information linear population, the synchronization part of the information and entropy is absent. The population size, M+1, is the third key metric in this methodology. Namely, right supposing a population with infinite size, the most of the key quantities and results for populations with finite size, emerged in this methodology, vanish.

  14. EFFECTS OF CHRONIC STRESS ON WILDLIFE POPULATIONS: A POPULATION MODELING APPROACH AND CASE STUDY

    EPA Science Inventory

    This chapter describes a matrix modeling approach to characterize and project risks to wildlife populations subject to chronic stress. Population matrix modeling was used to estimate effects of one class of environmental contaminants, dioxin-like compounds (DLCs), to populations ...

  15. Population growth and consumption.

    PubMed

    Chalkley, K

    1997-04-01

    The relationship between population growth, resource consumption, and environmental degradation is complex. The rise in "greenhouse gases" that will cause climatic change is clearly due to human activity, and pollutants are often concentrated in densely populated areas. However, even an area with a negative population growth, such as Russia, can experience severe environmental degradation due to poor management. Consumption patterns have the most effect on ozone depletion, while population growth threatens biodiversity of and within species through the destruction of ecosystems. Migration joins population growth and social factors, such as land inequality, as major causes of deforestation, and global demand for water is expected to increase faster than the rate of population growth. Coastal development and over-fishing threaten to deplete the oceans, while soil quality is threatened by inappropriate land use. Estimates of the earth's carrying capacity range from less than 3 billion to more than 44 billion people, indicating how difficult it is to assess this figure. Development efforts throughout the world may lead to human gains that will ultimately be negated by environmental losses. These factors have led to growing support for environmentally sustainable development.

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

    PubMed Central

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

    2016-01-01

    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

  17. The Population Threat

    ERIC Educational Resources Information Center

    McNamara, Robert S.

    1969-01-01

    In an address delivered at the University of Notre Dame, May 1969, Secretary McNamara discussed the threat of unmanageable population pressure which is undervalued and misunderstood by the general public. Unrestricted population growth will have catastrophic consequences unless it is dealt with rapidly and rationally. Copies from: Office of…

  18. The Population Care Coordination Process.

    PubMed

    Rushton, Sharron

    2015-01-01

    The purpose of the article was to outline a population-based approach to providing care coordination. The Population Care Coordination Process provides a framework for each provider and/or organization to provide multilevel care based on population- and patient-centered principles. The Population Care Coordination Process is scalable. It can be utilized in a smaller scale such as single provider office or in a larger scale such as an accountable care organization. There are many issues within our current health care structure that must be addressed. Care coordination has been identified as a potential solution to address the needs of complex patients within the system. The expansion to consider populations allows for a more targeted and efficient approach. The population care process entails a data-driven approach to care coordination. The inclusion of populations in the care coordination process provides an opportunity to maximize efforts and improve outcomes.

  19. A general population-genetic model for the production by population structure of spurious genotype-phenotype associations in discrete, admixed or spatially distributed populations.

    PubMed

    Rosenberg, Noah A; Nordborg, Magnus

    2006-07-01

    In linkage disequilibrium mapping of genetic variants causally associated with phenotypes, spurious associations can potentially be generated by any of a variety of types of population structure. However, mathematical theory of the production of spurious associations has largely been restricted to population structure models that involve the sampling of individuals from a collection of discrete subpopulations. Here, we introduce a general model of spurious association in structured populations, appropriate whether the population structure involves discrete groups, admixture among such groups, or continuous variation across space. Under the assumptions of the model, we find that a single common principle--applicable to both the discrete and admixed settings as well as to spatial populations--gives a necessary and sufficient condition for the occurrence of spurious associations. Using a mathematical connection between the discrete and admixed cases, we show that in admixed populations, spurious associations are less severe than in corresponding mixtures of discrete subpopulations, especially when the variance of admixture across individuals is small. This observation, together with the results of simulations that examine the relative influences of various model parameters, has important implications for the design and analysis of genetic association studies in structured populations.

  20. Identification of population substructure among Jews using STR markers and dependence on reference populations included.

    PubMed

    Listman, Jennifer B; Hasin, Deborah; Kranzler, Henry R; Malison, Robert T; Mutirangura, Apiwat; Sughondhabirom, Atapol; Aharonovich, Efrat; Spivak, Baruch; Gelernter, Joel

    2010-06-14

    Detecting population substructure is a critical issue for association studies of health behaviors and other traits. Whether inherent in the population or an artifact of marker choice, determining aspects of a population's genetic history as potential sources of substructure can aid in design of future genetic studies. Jewish populations, among which association studies are often conducted, have a known history of migrations. As a necessary step in understanding population structure to conduct valid association studies of health behaviors among Israeli Jews, we investigated genetic signatures of this history and quantified substructure to facilitate future investigations of these phenotypes in this population. Using 32 autosomal STR markers and the program STRUCTURE, we differentiated between Ashkenazi (AJ, N = 135) and non-Ashkenazi (NAJ, N = 226) Jewish populations in the form of Northern and Southern geographic genetic components (AJ north 73%, south 23%, NAJ north 33%, south 60%). The ability to detect substructure within these closely related populations using a small STR panel was contingent on including additional samples representing major continental populations in the analyses. Although clustering programs such as STRUCTURE are designed to assign proportions of ancestry to individuals without reference population information, when Jewish samples were analyzed in the absence of proxy parental populations, substructure within Jews was not detected. Generally, for samples with a given grandparental country of birth, STRUCTURE assignment values to Northern, Southern, African and Asian clusters agreed with mitochondrial DNA and Y-chromosomal data from previous studies as well as historical records of migration and intermarriage.

  1. Identification of population substructure among Jews using STR markers and dependence on reference populations included

    PubMed Central

    2010-01-01

    Background Detecting population substructure is a critical issue for association studies of health behaviors and other traits. Whether inherent in the population or an artifact of marker choice, determining aspects of a population's genetic history as potential sources of substructure can aid in design of future genetic studies. Jewish populations, among which association studies are often conducted, have a known history of migrations. As a necessary step in understanding population structure to conduct valid association studies of health behaviors among Israeli Jews, we investigated genetic signatures of this history and quantified substructure to facilitate future investigations of these phenotypes in this population. Results Using 32 autosomal STR markers and the program STRUCTURE, we differentiated between Ashkenazi (AJ, N = 135) and non-Ashkenazi (NAJ, N = 226) Jewish populations in the form of Northern and Southern geographic genetic components (AJ north 73%, south 23%, NAJ north 33%, south 60%). The ability to detect substructure within these closely related populations using a small STR panel was contingent on including additional samples representing major continental populations in the analyses. Conclusions Although clustering programs such as STRUCTURE are designed to assign proportions of ancestry to individuals without reference population information, when Jewish samples were analyzed in the absence of proxy parental populations, substructure within Jews was not detected. Generally, for samples with a given grandparental country of birth, STRUCTURE assignment values to Northern, Southern, African and Asian clusters agreed with mitochondrial DNA and Y-chromosomal data from previous studies as well as historical records of migration and intermarriage. PMID:20546593

  2. Genetic composition of captive panda population.

    PubMed

    Yang, Jiandong; Shen, Fujun; Hou, Rong; Da, Yang

    2016-10-03

    A major function of the captive panda population is to preserve the genetic diversity of wild panda populations in their natural habitats. Understanding the genetic composition of the captive panda population in terms of genetic contributions from the wild panda populations provides necessary knowledge for breeding plans to preserve the genetic diversity of the wild panda populations. The genetic contributions from different wild populations to the captive panda population were highly unbalanced, with Qionglai accounting for 52.2 % of the captive panda gene pool, followed by Minshan with 21.5 %, Qinling with 10.6 %, Liangshan with 8.2 %, and Xiaoxiangling with 3.6 %, whereas Daxiangling, which had similar population size as Xiaoxiangling, had no genetic representation in the captive population. The current breeding recommendations may increase the contribution of some small wild populations at the expense of decreasing the contributions of other small wild populations, i.e., increasing the Xiaoxiangling contribution while decreasing the contribution of Liangshan, or sharply increasing the Qinling contribution while decreasing the contributions of Xiaoxiangling and Liangshan, which were two of the three smallest wild populations and were already severely under-represented in the captive population. We developed three habitat-controlled breeding plans that could increase the genetic contributions from the smallest wild populations to 6.7-11.2 % for Xiaoxiangling, 11.5-12.3 % for Liangshan and 12.9-20.0 % for Qinling among the offspring of one breeding season while reducing the risk of hidden inbreeding due to related founders from the same habitat undetectable by pedigree data. The three smallest wild panda populations of Daxiangling, Xiaoxiangling and Liangshan either had no representation or were severely unrepresented in the current captive panda population. By incorporating the breeding goal of increasing the genetic contributions from the smallest wild

  3. 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

  4. Population modelling to compare chronic external radiotoxicity between individual and population endpoints in four taxonomic groups.

    PubMed

    Alonzo, Frédéric; Hertel-Aas, Turid; Real, Almudena; Lance, Emilie; Garcia-Sanchez, Laurent; Bradshaw, Clare; Vives I Batlle, Jordi; Oughton, Deborah H; Garnier-Laplace, Jacqueline

    2016-02-01

    In this study, we modelled population responses to chronic external gamma radiation in 12 laboratory species (including aquatic and soil invertebrates, fish and terrestrial mammals). Our aim was to compare radiosensitivity between individual and population endpoints and to examine how internationally proposed benchmarks for environmental radioprotection protected species against various risks at the population level. To do so, we used population matrix models, combining life history and chronic radiotoxicity data (derived from laboratory experiments and described in the literature and the FREDERICA database) to simulate changes in population endpoints (net reproductive rate R0, asymptotic population growth rate λ, equilibrium population size Neq) for a range of dose rates. Elasticity analyses of models showed that population responses differed depending on the affected individual endpoint (juvenile or adult survival, delay in maturity or reduction in fecundity), the considered population endpoint (R0, λ or Neq) and the life history of the studied species. Among population endpoints, net reproductive rate R0 showed the lowest EDR10 (effective dose rate inducing 10% effect) in all species, with values ranging from 26 μGy h(-1) in the mouse Mus musculus to 38,000 μGy h(-1) in the fish Oryzias latipes. For several species, EDR10 for population endpoints were lower than the lowest EDR10 for individual endpoints. Various population level risks, differing in severity for the population, were investigated. Population extinction (predicted when radiation effects caused population growth rate λ to decrease below 1, indicating that no population growth in the long term) was predicted for dose rates ranging from 2700 μGy h(-1) in fish to 12,000 μGy h(-1) in soil invertebrates. A milder risk, that population growth rate λ will be reduced by 10% of the reduction causing extinction, was predicted for dose rates ranging from 24 μGy h(-1) in mammals to 1800 μGy h(-1) in

  5. Pathological Differences in Heterodera schachtii Populations

    PubMed Central

    Griffin, G. D.

    1981-01-01

    Five populations of Heterodera schachtii Schm. from Oregon, Idaho, and Utah did not differ significantly in seedling penetration and rate of emergence and virulence. Another Utah H. schachtii population (Utah 2), however, differed from these five populations in all of the above-mentioned characteristics. More H. schachtii larvae of the Utah 2 population than the other populations penetrated sugarbeet seedlings at 10, 15, 20, and 25 C. Root and top weights of sugarbeet plants were signiticantly less when roots were parasitized by the Utah 2 population than when they were parasitized by larvae of the other nematode populations under similar experimental conditions. Also, the period of larval emergence was shorter in the Utah 2 population than in any of the other H. schachtii populations. PMID:19300743

  6. Mathematical modeling in biological populations through branching processes. Application to salmonid populations.

    PubMed

    Molina, Manuel; Mota, Manuel; Ramos, Alfonso

    2015-01-01

    This work deals with mathematical modeling through branching processes. We consider sexually reproducing animal populations where, in each generation, the number of progenitor couples is determined in a non-predictable environment. By using a class of two-sex branching processes, we describe their demographic dynamics and provide several probabilistic and inferential contributions. They include results about the extinction of the population and the estimation of the offspring distribution and its main moments. We also present an application to salmonid populations.

  7. 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.

  8. Population Health and Occupational Therapy.

    PubMed

    Braveman, Brent

    2016-01-01

    Occupational therapy practitioners play an important role in improving the health of populations through the development of occupational therapy interventions at the population level and through advocacy to address occupational participation and the multiple determinants of health. This article defines and explores population health as a concept and describes the appropriateness of occupational therapy practice in population health. Support of population health practice as evidenced in the official documents of the American Occupational Therapy Association and the relevance of population health for occupational therapy as a profession are reviewed. Recommendations and directions for the future are included related to celebration of the achievements of occupational therapy practitioners in the area of population health, changes to the Occupational Therapy Practice Framework and educational accreditation standards, and the importance of supporting, recognizing, rewarding, and valuing occupational therapy practitioners who assume roles in which direct care is not their primary function. Copyright © 2016 by the American Occupational Therapy Association, Inc.

  9. Kidney Disease in Disadvantaged Populations

    PubMed Central

    Martins, David; Agodoa, Lawrence; Norris, Keith

    2012-01-01

    Disadvantaged populations across the globe exhibit a disproportionate burden of chronic kidney disease (CKD) because of differences in CKD occurrence and outcomes. Although many CKD risk factors can be managed and modified to optimize clinical outcomes, the prevailing socioeconomic and cultural factors in disadvantaged populations, more often than not, militate against optimum clinical outcomes. In addition, disadvantaged populations exhibit a broader spectrum of CKD risk factors and may be genetically predisposed to an earlier onset and a more rapid progression of chronic kidney disease. A basic understanding of the vulnerabilities of the disadvantaged populations will facilitate the adaptation and adoption of the kidney disease treatment and prevention guidelines for these vulnerable populations. The purpose of this paper is to examine recent discoveries and data on CKD occurrence and outcomes in disadvantaged populations and explore strategies for the prevention and treatment of CKD in these populations based on the established guidelines. PMID:22567281

  10. Population and development.

    PubMed

    Pavlik, Z

    1995-01-01

    During the Paleolithic period, 10,000-100,000 people lived on the earth; their number exceeded 1 million at the beginning of the Neolithic period, reached 10 million during the Bronze Age, 100 million at the beginning of the Iron Age, 1 billion at the beginning of the 19th century, and 5.7 billion in 1995. The estimated global population will be 10 billion by the middle of the 21st century and is expected to stabilize at around 10-12 billion subsequently. Increased agricultural production helped bring about greater numbers of humanity and the advancement of society with a developing social hierarchy, although life expectancy was low at 22-28 years. In Europe, the Renaissance gradually evolved into the Industrial Revolution, and a demographic revolution accompanied this process. In some countries, population size increased more than five times. Eventually, mortality and fertility levels decreased and life expectancy increased. In Western civilization, increased individualism, secularization, compulsory school attendance, decreased agricultural population, emancipation of women, increased costs of raising children, and social and economic progress ensued. All this was preceded by 18th century conditions, when, in England, capital accumulation led to wealth on the one side and destitution on the other, giving rise to Malthus's famous theory. However, during the 19th century these social inequalities gradually evened out. After World War II, the question arose of whether the populations of other civilizations (Confucian, Japanese, Islamic, Hindu, Slavic-Orthodox, Latin American, and African) would also undergo a demographic transition and how soon. At any rate, developed country population size, as a percentage of global population, will drop from 22% to 13%, and that of Africa will increase from 12% to 26%, during the 21st century.

  11. Isolated populations of a rare alpine plant show high genetic diversity and considerable population differentiation.

    PubMed

    Aegisdóttir, Hafdís Hanna; Kuss, Patrick; Stöcklin, Jürg

    2009-12-01

    Gene flow and genetic variability within and among alpine plant populations can be greatly influenced by the steep environmental gradients and heterogeneous topography of alpine landscapes. In this study, the effects are examined of natural isolation of alpine habitats on genetic diversity and geographic structure in populations of C. thyrsoides, a rare and isolated European Alpine monocarpic perennial with limited seed dispersal capacity. Molecular diversity was analysed for 736 individuals from 32 populations in the Swiss Alps and adjacent Jura mountains using five polymorphic microsatellite loci. Pollen flow was estimated using pollen grain-sized fluorescent powder. In addition, individual-based Bayesian approaches were applied to examine population structure. High within-population genetic diversity (H(E) = 0.76) and a relatively low inbreeding coefficient (F(IS) = 0.022) were found. Genetic differentiation among populations measured with a standardized measure was considerable (G'(ST) = 0.53). A significant isolation-by-distance relationship was found (r = 0.62, P < 0.001) and a significant geographic sub-structure, coinciding with proposed postglacial migration patterns. Altitudinal location and size of populations did not influence molecular variation. Direct measures of pollen flow revealed that insect-mediated pollen dispersal was restricted to short distances within a population. The natural isolation of suitable habitats for C. thyrsoides restricts gene flow among the populations as expected for a monocarpic species with very limited seed dispersal capacities. The observed high within-population genetic diversity in this rare monocarpic perennial is best explained by its outcrossing behaviour, long-lived individuals and overlapping generations. Despite the high within-population genetic diversity, the considerable genetic differentiation and the clear western-eastern differentiation in this species merits consideration in future conservation efforts.

  12. Population education in Sierra Leone.

    PubMed

    Lucan, T A

    1985-06-01

    The 1977 Sierra Leone 3 year population education project had 5 objectives: 1) to develop a core of Sierra Leoneans qualified in population education, 2) to integrate population education concepts into the curriculum for secondary schools and teachers colleges, 3) to train teachers already engaged in trial teaching in pilot schools in the new integrated curricula to give support to their colleagues, 4) to integrate population education into the whole Sierra Leone educational system, and 5) to create an awareness of the implications of population growth on the socioeconomic development of the country. A 1977 seminar on the Social Studies and Population Education Program discussed population issues and economic and social development. The strategy recommended at the seminar was that both the minor and the major revision approaches be used in the integration of population education concepts into the existing curriculum of the National Program in Social Studies for the lower secondary level. A Spiral Curriculum was established in 1981 constructed of 6 topics: 1) man's origins, development, and characteristics; 2) man's environment; 3) man's culture; 4) population and resources; 5) communication in the service of man; and 6) global issues-achievement and problems. Both at in-service and at pre-servicetraining, the enquiry method of teaching was emphasized. By the end of December 1981, the curriculum in Social Studies integrated with Population Education was completed for secondary schools and secondary teachers' colleges. The availability of the textbooks that secondary school students will take to their homes for their parents to read will contribute immensely to the attainment of the development objective of creating an awareness of the implications and consequences of population growth on the socioeconomic development of the country.

  13. Aboriginal population prospects.

    PubMed

    Gray, A; Tesfaghiorghis, H

    1993-11-01

    The authors examine data from the 1986 and 1991 Australian censuses to assess discrepancies between the census data and past projections of the size and structure of the Aboriginal population. They also "comment on ways in which determinants of Aboriginal population change are diverging from the parameters used for previous projections. We pay particular attention to mortality prospects.... We note the evidence for under-enumeration of the Aboriginal population in particular age groups in the 1991 Census as in previous censuses, and estimate the size of adjustments necessary to correct for some, but not all, of these deficiencies. The analysis shows that Aboriginal fertility increased in the second half of the 1980s." excerpt

  14. Popullution: A Position Paper on Population.

    ERIC Educational Resources Information Center

    Durner, Mary Beth

    This position paper presents an interdisciplinary approach to the study of population. Six main sections are included in the paper: Introduction, The Growth of the Human Population, The Psychological Effects of Population Growth, Overpopulated America, Myths Concerning Population Growth and Control, and Population Education. Section 1, an…

  15. Strong fluctuations in aboveground population size do not limit genetic diversity in populations of an endangered biennial species.

    PubMed

    Münzbergová, Zuzana; Šurinová, Maria; Husáková, Iveta; Brabec, Jiří

    2018-04-26

    Assessing genetic diversity within populations of rare species and understanding its determinants are crucial for effective species protection. While a lot is known about the relationships between genetic diversity, fitness, and current population size, very few studies explored the effects of past population size. Knowledge of past population size may, however, improve our ability to predict future population fates. We studied Gentianella praecox subsp. bohemica, a biennial species with extensive seed bank. We tested the effect of current, past minimal and maximal population size, and harmonic mean of population sizes within the last 15 years on genetic diversity and fitness. Maximum population size over the last 15 years was the best predictor of expected heterozygosity of the populations and was significantly related to current population size and management. Plant fitness was significantly related to current as well as maximum population size and expected heterozygosity. The results suggested that information on past population size may improve our understanding of contemporary genetic diversity across populations. They demonstrated that despite the strong fluctuations in population size, large reductions in population size do not result in immediate loss of genetic diversity and reduction of fitness within the populations. This is likely due to the seed bank of the species serving as reservoir of the genetic diversity of the populations. From a conservation point of view, this suggests that the restoration of small populations of short-lived species with permanent seed bank is possible as these populations may still be genetically diverse.

  16. Population genetic analysis among five Indian population groups using six microsatellite markers.

    PubMed

    Ghosh, Anu; Das, Birajalaxmi; Seshadri, M

    2003-04-01

    Genetic variation at six tetranucleotide microsatellites (HUMTHO1, HUMVWA, F13A01, D3S1359, D12S66, and D12S67) has heen determined in five endogamous ethnic population groups of India belonging to two major linguistic families. The populations analyzed were Konkanastha Brahmins and Marathas (Maharashtra state) from the Indo-Aryan linguistic family and Nairs, Ezhavas, and Muslims (Kerala state) from the Dravidian family. All six loci show high gene diversity, ranging from 0.63 +/- 0.04 to 0.84 +/- 0.02. The average GST value observed was 1.7%, indicating that the differences between the populations account for less than 2% of the diversity, while the genetic variation is high within the five population groups studied (>98%). The phylogenetic tree fails to show any clear cluster. The absence of any cluster along with low average GST is suggestive of substantial genetic similarity among the studied populations, in spite of clear geographical, linguistic, and cultural barriers. This similarity indicates either a greater gene flow between these groups or, alternatively, may reflect a recent evolution for them, considering that the Indian caste system evolved only about 3000 years ago.

  17. PGG.Population: a database for understanding the genomic diversity and genetic ancestry of human populations

    PubMed Central

    Zhang, Chao; Gao, Yang; Liu, Jiaojiao; Xue, Zhe; Lu, Yan; Deng, Lian; Tian, Lei; Feng, Qidi

    2018-01-01

    Abstract There are a growing number of studies focusing on delineating genetic variations that are associated with complex human traits and diseases due to recent advances in next-generation sequencing technologies. However, identifying and prioritizing disease-associated causal variants relies on understanding the distribution of genetic variations within and among populations. The PGG.Population database documents 7122 genomes representing 356 global populations from 107 countries and provides essential information for researchers to understand human genomic diversity and genetic ancestry. These data and information can facilitate the design of research studies and the interpretation of results of both evolutionary and medical studies involving human populations. The database is carefully maintained and constantly updated when new data are available. We included miscellaneous functions and a user-friendly graphical interface for visualization of genomic diversity, population relationships (genetic affinity), ancestral makeup, footprints of natural selection, and population history etc. Moreover, PGG.Population provides a useful feature for users to analyze data and visualize results in a dynamic style via online illustration. The long-term ambition of the PGG.Population, together with the joint efforts from other researchers who contribute their data to our database, is to create a comprehensive depository of geographic and ethnic variation of human genome, as well as a platform bringing influence on future practitioners of medicine and clinical investigators. PGG.Population is available at https://www.pggpopulation.org. PMID:29112749

  18. Contributions of long-distance dispersal to population growth in colonising Pinus ponderosa populations.

    PubMed

    Lesser, Mark R; Jackson, Stephen T

    2013-03-01

    Long-distance dispersal is an integral part of plant species migration and population development. We aged and genotyped 1125 individuals in four disjunct populations of Pinus ponderosa that were initially established by long-distance dispersal in the 16th and 17th centuries. Parentage analysis was used to determine if individuals were the product of local reproductive events (two parents present), long-distance pollen dispersal (one parent present) or long-distance seed dispersal (no parents present). All individuals established in the first century at each site were the result of long-distance dispersal. Individuals reproduced at younger ages with increasing age of the overall population. These results suggest Allee effects, where populations were initially unable to expand on their own, and were dependent on long-distance dispersal to overcome a minimum-size threshold. Our results demonstrate that long-distance dispersal was not only necessary for initial colonisation but also to sustain subsequent population growth during early phases of expansion. © 2012 Blackwell Publishing Ltd/CNRS.

  19. Life history, population viability, and the potential for local adaptation in isolated trout populations

    Treesearch

    K. J. Carim; Y. Vindenes; L. A. Eby; C. Barfoot; L. A. Vollestad

    2017-01-01

    Habitat loss and fragmentation have caused population decline across taxa through impacts on life history diversity, dispersal patterns, and gene flow. Yet, intentional isolation of native fish populations is a frequently used management strategy to protect against negative interactions with invasive fish species. We evaluated the population viability and genetic...

  20. Population and policy in Finland.

    PubMed

    Hulkko, J

    1989-03-01

    Finland, with a population of 4.9 million, currently has an overall fertility rate of 1.6. There is a small population growth, but this is due to a large reproductive age group, return migration of Finns from Sweden, and a decrease in mortality that has increased the proportion of old people in the population. The state has no official population policy. A recommendation of the Finnish Committee on the World Population Year 1974 that the government establish an agency for population policy has not been adopted. The coalition government now in power has a program, however, aimed at influencing population growth. The program includes proposals to reduce work hours for parents with small children, increase the age limit for participation in the child allowance system, and increase the number of municipal day care facilities. Concerning regional policy, the government wants a balanced development of the country's different regions. Subsidiary industries of agriculture and forestry are being encouraged to preserve population levels in sparse areas. Finland also supports a health policy emphasizing preventive and non-institutional aspects of health care, with targets of life expectancy set at 82 years for women and 75 years for men by the year 2000.

  1. A Population Health Surveillance Theory

    PubMed Central

    Bigras-Poulin, Michel; Michel, Pascal; Ravel, André

    2012-01-01

    OBJECTIVES Despite its extensive use, the term "Surveillance" often takes on various meanings in the scientific literature pertinent to public health and animal health. A critical appraisal of this literature also reveals ambiguities relating to the scope and necessary structural components underpinning the surveillance process. The authors hypothesized that these inconsistencies translate to real or perceived deficiencies in the conceptual framework of population health surveillance. This paper presents a population health surveillance theory framed upon an explicit conceptual system relative to health surveillance performed in human and animal populations. METHODS The population health surveillance theory reflects the authors' system of thinking and was based on a creative process. RESULTS Population health surveillance includes two broad components: one relating to the human organization (which includes expertise and the administrative program), and one relating to the system per se (which includes elements of design and method) and which can be viewed as a process. The population health surveillance process is made of five sequential interrelated steps: 1) a trigger or need, 2) problem formulation, 3) surveillance planning, 4) surveillance implementation, and 5) information communication and audit. CONCLUSIONS The population health surveillance theory provides a systematic way of understanding, organizing and evaluating the population health surveillance process. PMID:23251837

  2. Soviet Marxism and population policy.

    PubMed

    Vonfrank, A

    1984-01-01

    American demographers have maintained that Marxism, notably Soviet Marxism, is consistently pronatalist. The Soviet view is said to be that population growth is not a problem and that birth control policies in either developed or developing societies are to be rejected; the "correct" (i.e., socialist) socioeconomic structure is the true solution to alleged population problems. Such representations of Soviet thought greatly oversimplify the Soviet position as well as fail to discern the changes in Soviet thought that have been occurring. Since the 1960s Soviet writers have increasingly acknowledged that population growth is, to a considerable degree, independent of the economic base of society and that conscious population policies may be needed to either increase or decrease the rate of population growth. Even socialist societies can have population problems. And where population growth is too rapid, as in the developing countries, policies to slow such growth are needed because of the threat to economic development. However, the Soviets continue to stress that birth control policies must go hand-in-hand with social and economic development policies if they are to be effective.

  3. Population modeling for furbearer management

    USGS Publications Warehouse

    Johnson, D.H.; Sanderson, G.C.

    1982-01-01

    The management of furbearers has become increasingly complex as greater demands are placed on their populations. Correspondingly, needs for information to use in management have increased. Inadequate information leads the manager to err on the conservative side; unless the size of the 'harvestable surplus' is known, the population cannot be fully exploited. Conversely, information beyond what is needed becomes an unaffordable luxury. Population modeling has proven useful for organizing information on numerous game animals. Modeling serves to determine if information of the right kind and proper amount is being gathered; systematizes data collection, data interpretation, and decision making; and permits more effective management and better utilization of game populations. This report briefly reviews the principles of population modeling, describes what has been learned from previous modeling efforts on furbearers, and outlines the potential role of population modeling in furbearer management.

  4. Population and the World Bank.

    PubMed

    Sankaran, S

    1973-12-01

    The World Bank Group regards excessive population growth as the single greatest obstacle to economic and social advance in the underdeveloped world. Since 1969 the Bank and the International Development Agency have provided countries with technical assistance through education, fact-finding, and analysis and given 65.7 million dollars for population projects. These projects, in India, Indonesia, Iran, Jamaica, and Malaysia provide training centers, population education, research, and evaluation as well as actual construction of clinics and mobile units. Because population planning touches sensitive areas of religion, caste, race, morality, and politics, the involved nation's political commitment to plan population growth is critical to the success of any program.

  5. The effects of spatial population dataset choice on estimates of population at risk of disease

    PubMed Central

    2011-01-01

    Background The spatial modeling of infectious disease distributions and dynamics is increasingly being undertaken for health services planning and disease control monitoring, implementation, and evaluation. Where risks are heterogeneous in space or dependent on person-to-person transmission, spatial data on human population distributions are required to estimate infectious disease risks, burdens, and dynamics. Several different modeled human population distribution datasets are available and widely used, but the disparities among them and the implications for enumerating disease burdens and populations at risk have not been considered systematically. Here, we quantify some of these effects using global estimates of populations at risk (PAR) of P. falciparum malaria as an example. Methods The recent construction of a global map of P. falciparum malaria endemicity enabled the testing of different gridded population datasets for providing estimates of PAR by endemicity class. The estimated population numbers within each class were calculated for each country using four different global gridded human population datasets: GRUMP (~1 km spatial resolution), LandScan (~1 km), UNEP Global Population Databases (~5 km), and GPW3 (~5 km). More detailed assessments of PAR variation and accuracy were conducted for three African countries where census data were available at a higher administrative-unit level than used by any of the four gridded population datasets. Results The estimates of PAR based on the datasets varied by more than 10 million people for some countries, even accounting for the fact that estimates of population totals made by different agencies are used to correct national totals in these datasets and can vary by more than 5% for many low-income countries. In many cases, these variations in PAR estimates comprised more than 10% of the total national population. The detailed country-level assessments suggested that none of the datasets was consistently more

  6. Where is Population II?

    NASA Astrophysics Data System (ADS)

    Mould, J.; Bianchini, F.; Forbes, Duncan A.; Reichardt, C. L.

    2018-03-01

    The use of roman numerals for stellar populations represents a classification approach to galaxy formation which is now well behind us. Nevertheless, the concept of a pristine generation of stars, followed by a protogalactic era, and finally the mainstream stellar population is a plausible starting point for testing our physical understanding of early star formation. This will be observationally driven as never before in the coming decade. In this paper, we search out observational tests of an idealised coeval and homogeneous distribution of population II stars. We examine the spatial distribution of quasars, globular clusters, and the integrated free electron density of the intergalactic medium, in order to test the assumption of homogeneity. Any real inhomogeneity implies a population II that is not coeval.

  7. Distance Learning for Special Populations

    ERIC Educational Resources Information Center

    Bates, Rodger A.

    2012-01-01

    Distance education strategies for remotely deployed, highly mobile, or institutionalized populations are reviewed and critiqued. Specifically, asynchronous, offline responses for special military units, Native Americans on remote reservations, prison populations and other geographically, temporally or technologically isolated niche populations are…

  8. Population and Housing Unit Estimates

    Science.gov Websites

    United States Census Bureau Topics Population Latest Information Age and Sex Ancestry Children Mobility Population Estimates Population Projections Race Veterans Economy Latest Information Portal Other Economic Programs Business Latest Information Business Characteristics Classification Codes

  9. Population genomics reveals that an anthropophilic population of Aedes aegypti mosquitoes in West Africa recently gave rise to American and Asian populations of this major disease vector.

    PubMed

    Crawford, Jacob E; Alves, Joel M; Palmer, William J; Day, Jonathan P; Sylla, Massamba; Ramasamy, Ranjan; Surendran, Sinnathamby N; Black, William C; Pain, Arnab; Jiggins, Francis M

    2017-02-28

    The mosquito Aedes aegypti is the main vector of dengue, Zika, chikungunya and yellow fever viruses. This major disease vector is thought to have arisen when the African subspecies Ae. aegypti formosus evolved from being zoophilic and living in forest habitats into a form that specialises on humans and resides near human population centres. The resulting domestic subspecies, Ae. aegypti aegypti, is found throughout the tropics and largely blood-feeds on humans. To understand this transition, we have sequenced the exomes of mosquitoes collected from five populations from around the world. We found that Ae. aegypti specimens from an urban population in Senegal in West Africa were more closely related to populations in Mexico and Sri Lanka than they were to a nearby forest population. We estimate that the populations in Senegal and Mexico split just a few hundred years ago, and we found no evidence of Ae. aegypti aegypti mosquitoes migrating back to Africa from elsewhere in the tropics. The out-of-Africa migration was accompanied by a dramatic reduction in effective population size, resulting in a loss of genetic diversity and rare genetic variants. We conclude that a domestic population of Ae. aegypti in Senegal and domestic populations on other continents are more closely related to each other than to other African populations. This suggests that an ancestral population of Ae. aegypti evolved to become a human specialist in Africa, giving rise to the subspecies Ae. aegypti aegypti. The descendants of this population are still found in West Africa today, and the rest of the world was colonised when mosquitoes from this population migrated out of Africa. This is the first report of an African population of Ae. aegypti aegypti mosquitoes that is closely related to Asian and American populations. As the two subspecies differ in their ability to vector disease, their existence side by side in West Africa may have important implications for disease transmission.

  10. Population remains top priority for China.

    PubMed

    Li, H

    1998-04-01

    China, whose population was 430 million in 1840, is facing a population total of 1.3 billion in 2000. Population increased rapidly in the country during the 1950s, but early efforts at population control were abandoned from the start of the Cultural Revolution in 1966 until the 1970s. Today, the importance of family planning (FP) is recognized throughout Chinese society. With 20 million newborns adding 13 million people to the population each year, controlling the population increase will remain a top priority of China's population policy. Other priorities include 1) increasing the quality of life of the population by improving health, promoting literacy, and developing human resources; 2) facing the impact of population aging; 3) struggling to overcome the poverty experienced by 50 million people; and 4) dealing with the imbalanced sex ratio of newborns. China has been attempting to institute strategies to implement the Program of Action adopted by the 1994 International Conference on Population and Development and is attempting to adopt an integrated approach to population programs that combines FP with development measures and the delivery of multiple services to enhance reproductive health. Since 1984, China has worked with Japan's JOICFP on an Integrated Project that offers FP, maternal and child health services, and parasite control.

  11. PGG.Population: a database for understanding the genomic diversity and genetic ancestry of human populations.

    PubMed

    Zhang, Chao; Gao, Yang; Liu, Jiaojiao; Xue, Zhe; Lu, Yan; Deng, Lian; Tian, Lei; Feng, Qidi; Xu, Shuhua

    2018-01-04

    There are a growing number of studies focusing on delineating genetic variations that are associated with complex human traits and diseases due to recent advances in next-generation sequencing technologies. However, identifying and prioritizing disease-associated causal variants relies on understanding the distribution of genetic variations within and among populations. The PGG.Population database documents 7122 genomes representing 356 global populations from 107 countries and provides essential information for researchers to understand human genomic diversity and genetic ancestry. These data and information can facilitate the design of research studies and the interpretation of results of both evolutionary and medical studies involving human populations. The database is carefully maintained and constantly updated when new data are available. We included miscellaneous functions and a user-friendly graphical interface for visualization of genomic diversity, population relationships (genetic affinity), ancestral makeup, footprints of natural selection, and population history etc. Moreover, PGG.Population provides a useful feature for users to analyze data and visualize results in a dynamic style via online illustration. The long-term ambition of the PGG.Population, together with the joint efforts from other researchers who contribute their data to our database, is to create a comprehensive depository of geographic and ethnic variation of human genome, as well as a platform bringing influence on future practitioners of medicine and clinical investigators. PGG.Population is available at https://www.pggpopulation.org. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  12. Integral control for population management.

    PubMed

    Guiver, Chris; Logemann, Hartmut; Rebarber, Richard; Bill, Adam; Tenhumberg, Brigitte; Hodgson, Dave; Townley, Stuart

    2015-04-01

    We present a novel management methodology for restocking a declining population. The strategy uses integral control, a concept ubiquitous in control theory which has not been applied to population dynamics. Integral control is based on dynamic feedback-using measurements of the population to inform management strategies and is robust to model uncertainty, an important consideration for ecological models. We demonstrate from first principles why such an approach to population management is suitable via theory and examples.

  13. Population Analysis: Communicating in Context

    NASA Technical Reports Server (NTRS)

    Rajulu, Sudhakar; Thaxton, Sherry

    2008-01-01

    Providing accommodation to a widely varying user population presents a challenge to engineers and designers. It is often even difficult to quantify who is accommodated and who is not accommodated by designs, especially for equipment with multiple critical anthropometric dimensions. An approach to communicating levels of accommodation referred to as population analysis applies existing human factors techniques in novel ways. This paper discusses the definition of population analysis as well as major applications and case studies. The major applications of population analysis consist of providing accommodation information for multivariate problems and enhancing the value of feedback from human-in-the-loop testing. The results of these analyses range from the provision of specific accommodation percentages of the user population to recommendations of design specifications based on quantitative data. Such feedback is invaluable to designers and results in the design of products that accommodate the intended user population.

  14. Probabilistic population aging

    PubMed Central

    2017-01-01

    We merge two methodologies, prospective measures of population aging and probabilistic population forecasts. We compare the speed of change and variability in forecasts of the old age dependency ratio and the prospective old age dependency ratio as well as the same comparison for the median age and the prospective median age. While conventional measures of population aging are computed on the basis of the number of years people have already lived, prospective measures are computed also taking account of the expected number of years they have left to live. Those remaining life expectancies change over time and differ from place to place. We compare the probabilistic distributions of the conventional and prospective measures using examples from China, Germany, Iran, and the United States. The changes over time and the variability of the prospective indicators are smaller than those that are observed in the conventional ones. A wide variety of new results emerge from the combination of methodologies. For example, for Germany, Iran, and the United States the likelihood that the prospective median age of the population in 2098 will be lower than it is today is close to 100 percent. PMID:28636675

  15. GENETICS AND POPULATION-LEVEL RISK ASSESSMENT

    EPA Science Inventory

    Genetic variation defines population structure and provides the mechanism for populations to adapt to novel stressors. Despite its fundamental importance in understanding populations, genetic information has been included rarely in models of population dynamics (endangered speci...

  16. Declining scaup populations: A retrospective analysis of long-term population and harvest survey data

    USGS Publications Warehouse

    Afton, A.D.; Anderson, M.G.

    2001-01-01

    We examined long-term databases concerning population status of scaup (lesser [Aythya affinis] and greater scaup [A. marila] combined) and harvest statistics of lesser scaup to identify factors potentially limiting population growth. Specifically, we explored evidence for and against the general hypotheses that scaup populations have declined in association with declining recruitment and/or female survival. We examined geographic heterogeneity in scaup demographic patterns that could yield evidence about potential limiting factors. Several biases exist in survey methodology used to estimate scaup populations and harvest statistics; however, none of these biases likely accounted for our major findings that (1) the continental scaup breeding population has declined over the last 20 years, with widespread and consistent declines within surveyed areas of the Canadian western boreal forest where most lesser scaup breed; (2) sex ratios of lesser scaup in the U.S. harvest have increased (more males now relative to females); and (3) age ratios of lesser scaup in the U.S. harvest have declined (fewer immatures now relative to adults), especially in the midcontinent region. We interpreted these major findings as evidence that (1) recruitment of lesser scaup has declined over the last 20 years, particularly in the Canadian western boreal forest; and (2) survival of female lesser scaup has declined relative to that of males. We found little evidence that harvest was associated with the scaup population decline. Our findings underscore the need for both improvements and changes to population survey procedures and new research to discriminate among various hypotheses explaining the recent scaup population decline.

  17. Capital, population and urban patterns.

    PubMed

    Zhang, W

    1994-04-01

    The author develops an approach to urban dynamics with endogenous capital and population growth, synthesizing the Alonso location model, the two-sector neoclassical growth model, and endogenous population theory. A dynamic model for an isolated island economy with endogenous capital, population, and residential structure is developed on the basis of Alonso's residential model and the two-sector neoclassical growth model. The model describes the interdependence between residential structure, economic growth, population growth, and economic structure over time and space. It has a unique long-run equilibrium, which may be either stable or unstable, depending upon the population dynamics. Applying the Hopf theorem, the author also shows that when the system is unstable, the economic geography exhibits permanent endogenous oscillations.

  18. Estimating population parameters for northern and southern breeding populations of Canada geese

    USGS Publications Warehouse

    Hestbeck, J.B.; Rusch, Donald H.; Samuel, Michael D.; Humburg, Dale D.; Sullivan, Brian D.

    1998-01-01

    Canada geese (Branta canadensis) have been managed largely as a migratory resource. In the 1960's, Canada goose flocks were restored to historic breeding ranges in the United States and southern Canada to enhance recreational opportunity for observation and harvest. These populations of southern breeding geese have rapidly expanded, increasing conflicts with social and economic interests and causing the Midwinter Waterfowl Survey to be less effective as a management tool to monitor migrant populations. Wildlife agencies need methods to control local, southern breeding geese that reduce conflicts while providing adequate protection to populations of northern breeding geese. New techniques have been developed using mark-resight data from neck-banded geese to estimate distribution and population size during the late summer, fall, and mid-winter. Survival and movement rates can be estimated over special early or late hunting seasons, traditional fall-winter hunting season, and nonharvest periods. Direct recovery rates can be estimated for special and traditional harvest periods and these recovery rates can be related to survival and movement rates. Changes in harvest regulations can be related to changes in recovery, survival, and movement rates for specific cohorts of Canada geese. These techniques can be used to monitor population status and determine more appropriate harvest strategies.

  19. Population cycles in small rodents.

    PubMed

    Krebs, C J; Gaines, M S; Keller, B L; Myers, J H; Tamarin, R H

    1973-01-05

    We conclude that population fluctuations in Microtus in southern Indiana are produced by a syndrome of changes in birth and death rates similar to that found in other species of voles and lemmings. The mechanisms which cause the changes in birth and death rates are demolished by fencing the population so that no dispersal can occur. Dispersal thus seems critical for population regulation in Microtus. Because most dispersal occurs during the increase phase of the population cycle and there is little dispersal during the decline phase, dispersal is not directly related to population density. Hence the quality of dispersing animals must be important, and we have found one case of increased dispersal tendency by one genotype. The failure of population regulation of Microtus in enclosed areas requires an explanation by any hypothesis attempting to explain population cycles in small rodents. It might be suggested that the fence changed the predation pressure on the enclosed populations. However, the fence was only 2 feet (0.6 meter) high and did not stop the entrance of foxes, weasels, shrews, or avian predators. A striking feature was that the habitat in the enclosures quickly recovered from complete devastation by the start of the spring growing season. Obviously the habitat and food quality were sufficient to support Microtus populations of abnormally high densities, and recovery of the habitat was sufficiently quick that the introduction of new animals to these enclosed areas resulted in another population explosion. Finally, hypotheses of population regulation by social stress must account for the finding that Microtus can exist at densities several times greater than normal without "stress" taking an obvious toll. We hypothesize that the prevention of dispersal changes the quality of the populations in the enclosures in comparison to those outside the fence. Voles forced to remain in an overcrowded fenced population do not suffer high mortality rates and continue

  20. Colonial, more widely distributed and less abundant bird species undergo wider population fluctuations independent of their population trend

    PubMed Central

    Møller, Anders P.

    2017-01-01

    Understanding temporal variability in population size is important for conservation biology because wide population fluctuations increase the risk of extinction. Previous studies suggested that certain ecological, demographic, life-history and genetic characteristics of species might be related to the degree of their population fluctuations. We checked whether that was the case in a large sample of 231 European breeding bird species while taking a number of potentially confounding factors such as population trends or similarities among species due to common descent into account. When species-specific characteristics were analysed one by one, the magnitude of population fluctuations was positively related to coloniality, habitat, total breeding range, heterogeneity of breeding distribution and natal dispersal, and negatively related to urbanisation, abundance, relative number of subspecies, parasitism and proportion of polymorphic loci. However, when abundance (population size) was included in the analyses of the other parameters, only coloniality, habitat, total breeding range and abundance remained significantly related to population fluctuations. The analysis including all these predictors simultaneously showed that population size fluctuated more in colonial, less abundant species with larger breeding ranges. Other parameters seemed to be related to population fluctuations only because of their association with abundance or coloniality. The unexpected positive relationship between population fluctuations and total breeding range did not seem to be mediated by abundance. The link between population fluctuations and coloniality suggests a previously unrecognized cost of coloniality. The negative relationship between population size and population fluctuations might be explained by at least three types of non-mutually exclusive stochastic processes: demographic, environmental and genetic stochasticity. Measurement error in population indices, which was unknown, may

  1. Population and economics.

    PubMed

    Wright, W

    1995-06-01

    The first world consists of the developed industrial countries, the second consists of rapidly developing countries, and the third of less developed, largely pre-industrial countries. The economies of most developed countries in recent years have been relatively stagnant. Most people in the developed world therefore assume that the bottom of the business cycle has arrived and that an upturn will soon be forthcoming. With the exception of the USA and Chile, which have been moderately prosperous in the last few years, the bottom has persisted for a very long time. Indeed, the developed world is not caught in a conventional business cycle, but in something quite new and different. The first world is struggling to stay at the top of countries worldwide both economically and politically, but the second world is rapidly catching up. Populations in these latter countries are both better educated and willing to work harder per unit of capital compared to people in the first world. Marketplace forces and the communication highway are increasingly bring about a scenario in which the first and second worlds will be economic peers. Faced with increased competition from the second world and a larger number of countries capable of providing foreign aid to the third world, it should be clear that the first world will turn inward and reduce its annual aid contributions to less developed countries. It is, however, in the first world's interest to promote family planning toward the goal of reduced population growth. Developed countries should insist that a substantial fraction of whatever foreign aid is provided goes toward reducing the rate of population growth. The first priority should be to make contraceptives available and promote their use worldwide. Efforts should then be taken to empower women through educational and other programs. This approach will slow population growth and improve the economic productivity of both men and women. The Third World should also seriously

  2. Achieving true sustainability of zoo populations.

    PubMed

    Lacy, Robert C

    2013-01-01

    For the last 30 years, cooperative management of irreplaceable animal populations in zoos and aquariums has focused primarily on the goal of minimizing genetic decay within defined time frames, and large advances have been made in technologies to optimize genetic management of closed populations. However, recent analyses have shown that most zoo programs are not projected to meet their stated goals. This has been described as a lack of achieving "sustainability" of the populations, yet by definition a goal of managed decay is not a plan for sustainability. True sustainability requires management of the resource in manner that does not deplete its value for the future. Achieving such sustainability for many managed populations may require changing from managing isolated populations to managing populations that are part of a broader metapopulation, with carefully considered exchange between populations across a spectrum of ex situ to in situ. Managing zoo populations as components of comprehensive conservation strategies for the species will require research on determinants of various kinds of genetic, physiological, behavioral, and morphological variation and their roles in population viability, development of an array of management techniques and tools, training of population managers in metapopulation management and integrated conservation planning, and projections of impacts of management strategies on the viability of the captive populations and all populations that are interactively managed or affected. Such a shift in goals and methods would result in zoo population management being an ongoing part of species conservation rather than short-term or isolated from species conservation. Zoo Biol. 32:19-26, 2013. © 2012 Wiley Periodicals, Inc. © 2012 Wiley Periodicals, Inc.

  3. bayesPop: Probabilistic Population Projections

    PubMed Central

    Ševčíková, Hana; Raftery, Adrian E.

    2016-01-01

    We describe bayesPop, an R package for producing probabilistic population projections for all countries. This uses probabilistic projections of total fertility and life expectancy generated by Bayesian hierarchical models. It produces a sample from the joint posterior predictive distribution of future age- and sex-specific population counts, fertility rates and mortality rates, as well as future numbers of births and deaths. It provides graphical ways of summarizing this information, including trajectory plots and various kinds of probabilistic population pyramids. An expression language is introduced which allows the user to produce the predictive distribution of a wide variety of derived population quantities, such as the median age or the old age dependency ratio. The package produces aggregated projections for sets of countries, such as UN regions or trading blocs. The methodology has been used by the United Nations to produce their most recent official population projections for all countries, published in the World Population Prospects. PMID:28077933

  4. Quasispecies theory for finite populations

    PubMed Central

    Park, Jeong-Man; Muñoz, Enrique; Deem, Michael W.

    2015-01-01

    We present stochastic, finite-population formulations of the Crow-Kimura and Eigen models of quasispecies theory, for fitness functions that depend in an arbitrary way on the number of mutations from the wild type. We include back mutations in our description. We show that the fluctuation of the population numbers about the average values are exceedingly large in these physical models of evolution. We further show that horizontal gene transfer reduces by orders of magnitude the fluctuations in the population numbers and reduces the accumulation of deleterious mutations in the finite population due to Muller’s ratchet. Indeed the population sizes needed to converge to the infinite population limit are often larger than those found in nature for smooth fitness functions in the absence of horizontal gene transfer. These analytical results are derived for the steady-state by means of a field-theoretic representation. Numerical results are presented that indicate horizontal gene transfer speeds up the dynamics of evolution as well. PMID:20365394

  5. Population growth, poverty and health.

    PubMed

    Kibirige, J S

    1997-07-01

    One of the most popular explanations for the many problems that face Africa is population growth. Africa's population has doubled since 1960. Africa has the highest fertility rate in the world and the rate of population growth is higher than in any other region. At the same time, Africa faces a social and economic situation that is viewed by many as alarming. Among the problems that devastate Africa is that of persistent poor health. Africa has lower life expectancy, higher mortality rates and is affected by more disease and illness conditions than any other region. Focusing on sub-Saharan Africa, this paper examines the relationship between population growth, poverty and poor health. While most analyses have focused on population growth as an original cause of poverty and underdevelopment, this paper argues that while both population growth and poor health play a significant role in exacerbating the problem of poverty, they are themselves primary consequences of poverty rather than its cause.

  6. Natural Selection in Large Populations

    NASA Astrophysics Data System (ADS)

    Desai, Michael

    2011-03-01

    I will discuss theoretical and experimental approaches to the evolutionary dynamics and population genetics of natural selection in large populations. In these populations, many mutations are often present simultaneously, and because recombination is limited, selection cannot act on them all independently. Rather, it can only affect whole combinations of mutations linked together on the same chromosome. Methods common in theoretical population genetics have been of limited utility in analyzing this coupling between the fates of different mutations. In the past few years it has become increasingly clear that this is a crucial gap in our understanding, as sequence data has begun to show that selection appears to act pervasively on many linked sites in a wide range of populations, including viruses, microbes, Drosophila, and humans. I will describe approaches that combine analytical tools drawn from statistical physics and dynamical systems with traditional methods in theoretical population genetics to address this problem, and describe how experiments in budding yeast can help us directly observe these evolutionary dynamics.

  7. Genetic Population Structure of Local Populations of the Endangered Saltmarsh Sesarmid Crab Clistocoeloma sinense in Japan

    PubMed Central

    Yuhara, Takeshi; Kawane, Masako; Furota, Toshio

    2014-01-01

    During recent decades, over 40% of Japanese estuarine tidal flats have been lost due to coastal developments. Local populations of the saltmarsh sesarmid crab Clistocoeloma sinense, designated as an endangered species due to the limited suitable saltmarsh habitat available, have decreased accordingly, being now represented as small remnant populations. Several such populations in Tokyo Bay, have been recognised as representing distributional limits of the species. To clarify the genetic diversity and connectivity among local coastal populations of Japanese Clistocoeloma sinense, including those in Tokyo Bay, mitochondrial DNA analyses were conducted in the hope of providing fundamental information for future conservation studies and an understanding of metapopulation dynamics through larval dispersal among local populations. All of the populations sampled indicated low levels of genetic diversity, which may have resulted from recent population bottlenecks or founder events. However, the results also revealed clear genetic differentiation between two enclosed-water populations in Tokyo Bay and Ise-Mikawa Bay, suggesting the existence of a barrier to larval transport between these two water bodies. Since the maintenance of genetic connectivity is a requirement of local population stability, the preservation of extant habitats and restoration of saltmarshes along the coast of Japan may be the most effective measures for conservation of this endangered species. PMID:24400112

  8. Population connectivity and genetic structure of burbot (Lota lota) populations in the Wind River Basin, Wyoming

    USGS Publications Warehouse

    Underwood, Zachary E.; Mandeville, Elizabeth G.; Walters, Annika W.

    2016-01-01

    Burbot (Lota lota) occur in the Wind River Basin in central Wyoming, USA, at the southwestern extreme of the species’ native range in North America. The most stable and successful of these populations occur in six glacially carved mountain lakes on three different tributary streams and one large main stem impoundment (Boysen Reservoir) downstream from the tributary populations. Burbot are rarely found in connecting streams and rivers, which are relatively small and high gradient, with a variety of potential barriers to upstream movement of fish. We used high-throughput genomic sequence data for 11,197 SNPs to characterize the genetic diversity, population structure, and connectivity among burbot populations on the Wind River system. Fish from Boysen Reservoir and lower basin tributary populations were genetically differentiated from those in the upper basin tributary populations. In addition, fish within the same tributary streams fell within the same genetic clusters, suggesting there is movement of fish between lakes on the same tributaries but that populations within each tributary system are isolated and genetically distinct from other populations. Observed genetic differentiation corresponded to natural and anthropogenic barriers, highlighting the importance of barriers to fish population connectivity and gene flow in human-altered linked lake-stream habitats.

  9. Harvest and dynamics of duck populations

    USGS Publications Warehouse

    Sedinger, James S.; Herzog, Mark P.

    2012-01-01

    The role of harvest in the dynamics of waterfowl populations continues to be debated among scientists and managers. Our perception is that interested members of the public and some managers believe that harvest influences North American duck populations based on calls for more conservative harvest regulations. A recent review of harvest and population dynamics of North American mallard (Anas platyrhynchos) populations (Pöysä et al. 2004) reached similar conclusions. Because of the importance of this issue, we reviewed the evidence for an impact of harvest on duck populations. Our understanding of the effects of harvest is limited because harvest effects are typically confounded with those of population density; regulations are typically most liberal when populations are greatest. This problem also exists in the current Adaptive Harvest Management Program (Conn and Kendall 2004). Consequently, even where harvest appears additive to other mortality, this may be an artifact of ignoring effects of population density. Overall, we found no compelling evidence for strong additive effects of harvest on survival in duck populations that could not be explained by other factors.

  10. A Population of Assessment Tasks

    ERIC Educational Resources Information Center

    Daro, Phil; Burkhardt, Hugh

    2012-01-01

    We propose the development of a "population" of high-quality assessment tasks that cover the performance goals set out in the "Common Core State Standards for Mathematics." The population will be published. Tests are drawn from this population as a structured random sample guided by a "balancing algorithm."

  11. Suicide Prevention in Special Populations.

    ERIC Educational Resources Information Center

    Bogdaniak, Roman C.; Coronado, Maria G.

    Suicide prevention techniques, from a clinical perspective, need to be as diversified as the population they serve. In certain special population groups, suicide has reached epidemic proportions, and there is a significant public health need for specific suicide prevention strategies. Special populations need to be identified and their suicide…

  12. Population Education: A Knowledge Base.

    ERIC Educational Resources Information Center

    Jacobson, Willard J.

    To aid junior high and high school educators and curriculum planners as they develop population education programs, the book provides an overview of the population education knowledge base. In addition, it suggests learning activities, discussion questions, and background information which can be integrated into courses dealing with population,…

  13. Population momentum across vertebrate life histories

    USGS Publications Warehouse

    Koons, D.N.; Grand, J.B.; Arnold, J.M.

    2006-01-01

    Population abundance is critically important in conservation, management, and demographic theory. Thus, to better understand how perturbations to the life history affect long-term population size, we examined population momentum for four vertebrate classes with different life history strategies. In a series of demographic experiments we show that population momentum generally has a larger effect on long-term population size for organisms with long generation times than for organisms with short generation times. However, patterns between population momentum and generation time varied across taxonomic groups and according to the life history parameter that was changed. Our findings indicate that momentum may be an especially important aspect of population dynamics for long-lived vertebrates, and deserves greater attention in life history studies. Further, we discuss the importance of population momentum in natural resource management, pest control, and conservation arenas. ?? 2006 Elsevier B.V. All rights reserved.

  14. Stochastic gain in finite populations

    NASA Astrophysics Data System (ADS)

    Röhl, Torsten; Traulsen, Arne; Claussen, Jens Christian; Schuster, Heinz Georg

    2008-08-01

    Flexible learning rates can lead to increased payoffs under the influence of noise. In a previous paper [Traulsen , Phys. Rev. Lett. 93, 028701 (2004)], we have demonstrated this effect based on a replicator dynamics model which is subject to external noise. Here, we utilize recent advances on finite population dynamics and their connection to the replicator equation to extend our findings and demonstrate the stochastic gain effect in finite population systems. Finite population dynamics is inherently stochastic, depending on the population size and the intensity of selection, which measures the balance between the deterministic and the stochastic parts of the dynamics. This internal noise can be exploited by a population using an appropriate microscopic update process, even if learning rates are constant.

  15. 10 CFR 100.11 - Determination of exclusion area, low population zone, and population center distance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... population center distance. 100.11 Section 100.11 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) REACTOR SITE CRITERIA Evaluation Factors for Stationary Power Reactor Site Applications Before January 10, 1997 and for Testing Reactors § 100.11 Determination of exclusion area, low population zone, and population...

  16. 10 CFR 100.11 - Determination of exclusion area, low population zone, and population center distance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... population center distance. 100.11 Section 100.11 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) REACTOR SITE CRITERIA Evaluation Factors for Stationary Power Reactor Site Applications Before January 10, 1997 and for Testing Reactors § 100.11 Determination of exclusion area, low population zone, and population...

  17. Pesticide tolerance in amphibians: induced tolerance in susceptible populations, constitutive tolerance in tolerant populations

    PubMed Central

    Hua, Jessica; Morehouse, Nathan I; Relyea, Rick

    2013-01-01

    The role of plasticity in shaping adaptations is important to understanding the expression of traits within individuals and the evolution of populations. With increasing human impacts on the environment, one challenge is to consider how plasticity shapes responses to anthropogenic stressors such as contaminants. To our knowledge, only one study (using mosquitoes) has considered the possibility of induced insecticide tolerance. Using populations of wood frogs (Lithobates sylvaticus) located close to and far from agricultural fields, we discovered that exposing some populations of embryos and hatchlings to sublethal concentrations of the insecticide carbaryl induced higher tolerance to a subsequent lethal concentration later in life. Interestingly, the inducible populations were located >800 m from agricultural areas and were the most susceptible to the insecticide. In contrast, the noninducible populations were located close to agricultural areas and were the least susceptible. We also found that sublethal concentrations of carbaryl induced higher tadpole AChE concentrations in several cases. This is the first study to demonstrate inducible tolerance in a vertebrate species and the pattern of inducible and constitutive tolerance among populations suggests the process of genetic assimilation. PMID:24187585

  18. Population trends, survival, and sampling methodologies for a population of Rana draytonii

    USGS Publications Warehouse

    Fellers, Gary M.; Kleeman, Patrick M.; Miller, David A.W.; Halstead, Brian J.

    2017-01-01

    Estimating population trends provides valuable information for resource managers, but monitoring programs face trade-offs between the quality and quantity of information gained and the number of sites surveyed. We compared the effectiveness of monitoring techniques for estimating population trends of Rana draytonii (California Red-legged Frog) at Point Reyes National Seashore, California, USA, over a 13-yr period. Our primary goals were to: 1) estimate trends for a focal pond at Point Reyes National Seashore, and 2) evaluate whether egg mass counts could reliably estimate an index of abundance relative to more-intensive capture–mark–recapture methods. Capture–mark–recapture (CMR) surveys of males indicated a stable population from 2005 to 2009, despite low annual apparent survival (26.3%). Egg mass counts from 2000 to 2012 indicated that despite some large fluctuations, the breeding female population was generally stable or increasing, with annual abundance varying between 26 and 130 individuals. Minor modifications to egg mass counts, such as marking egg masses, can allow estimation of egg mass detection probabilities necessary to convert counts to abundance estimates, even when closure of egg mass abundance cannot be assumed within a breeding season. High egg mass detection probabilities (mean per-survey detection probability = 0.98 [0.89–0.99]) indicate that egg mass surveys can be an efficient and reliable method for monitoring population trends of federally threatened R. draytonii. Combining egg mass surveys to estimate trends at many sites with CMR methods to evaluate factors affecting adult survival at focal populations is likely a profitable path forward to enhance understanding and conservation of R. draytonii.

  19. Variance in binary stellar population synthesis

    NASA Astrophysics Data System (ADS)

    Breivik, Katelyn; Larson, Shane L.

    2016-03-01

    In the years preceding LISA, Milky Way compact binary population simulations can be used to inform the science capabilities of the mission. Galactic population simulation efforts generally focus on high fidelity models that require extensive computational power to produce a single simulated population for each model. Each simulated population represents an incomplete sample of the functions governing compact binary evolution, thus introducing variance from one simulation to another. We present a rapid Monte Carlo population simulation technique that can simulate thousands of populations in less than a week, thus allowing a full exploration of the variance associated with a binary stellar evolution model.

  20. Population dynamics of rural Ethiopia.

    PubMed

    Bariabagar, H

    1978-01-01

    2 rounds of the national sample surveys, conducted by the central statistical office of Ethiopia during 1964-1967 and 1969-1971, provide the only comprehensive demographic data for the country and are the basis for this discussion of rural Ethiopia's population dynamics. The population of Ethiopia is predominantly rural. Agglomerations of 2000 and over inhabitants constitute about 14% of the population, and this indicates that Ethiopia has a low level of urbanization. In rural Ethiopia, international migration was negligent in the 1970's and the age structure can be assumed to be the results of past trends of fertility and mortality conditions. The reported crude birthrate (38.2), crude death rate (12.3) and infant mortality rate (90) of rural Ethiopia fall short of the averages for African countries. Prospects of population growth of rural Ethiopia would be immense. At the rate of natural increase of between 2.4 and 3.0% per annum, the population would double in 24-29 years. Regarding population issues, the programs of the National Democratic Revolution of Ethiopia faces the following main challenging problems: 1) carrying out national population censuses in order to obtain basic information for socialist planning; 2) minimizing or curtailing the existing high urban growth rates; 3) reducing rapidly growing population; and 5) mobilizing Ethiopian women to participate in the social, economic and political life of the country in order to create favorable conditions for future fertility reduction.

  1. Anti-aging activities of extracts from Tunisian medicinal halophytes and their aromatic constituents

    PubMed Central

    Jdey, A.; Falleh, H.; Ben Jannet, S.; Mkadmini Hammi, K.; Dauvergne, X.; Magné, C.; Ksouri, R.

    2017-01-01

    Six medicinal halophytes widely represented in North Africa and commonly used in traditional medicine were screened for pharmacological properties to set out new promising sources of natural ingredients for cosmetic or nutraceutical applications. Thus, Citrullus colocynthis, Cleome arabica, Daemia cordata, Haloxylon articulatum, Pituranthos scoparius and Scorzonera undulata were examined for their in vitro antioxidant (DPPH scavenging and superoxide anion-scavenging, β-carotene bleaching inhibition and iron-reducing tests), antibacterial (microdilution method, against four human pathogenic bacteria) and anti-tyrosinase activities. Besides, their aromatic composition was determined by RP-HPLC. H. articulatum shoot extracts exhibited the strongest antioxidant activity and inhibited efficiently the growth of Salmonella enterica and Escherichia coli. P. scoparius and C. arabica inhibited slightly monophenolase, whereas H. articulatum was the most efficient inhibitor of diphenolase activity. Furthermore, H. articulatum exhibited the highest aromatic content (3.4 % DW), with dopamine as the major compound. These observations suggest that shoot extract of H. articulatum, and to a lesser extent of C. arabica, could be used as antioxidant, antibiotic as well as new natural skin lightening agents. Also, possible implication of aromatic compounds in anti-tyrosinase activity is discussed. PMID:28827992

  2. Anti-aging activities of extracts from Tunisian medicinal halophytes and their aromatic constituents.

    PubMed

    Jdey, A; Falleh, H; Ben Jannet, S; Mkadmini Hammi, K; Dauvergne, X; Magné, C; Ksouri, R

    2017-01-01

    Six medicinal halophytes widely represented in North Africa and commonly used in traditional medicine were screened for pharmacological properties to set out new promising sources of natural ingredients for cosmetic or nutraceutical applications. Thus, Citrullus colocynthis , Cleome arabica , Daemia cordata , Haloxylon articulatum , Pituranthos scoparius and Scorzonera undulata were examined for their in vitro antioxidant (DPPH scavenging and superoxide anion-scavenging, β -carotene bleaching inhibition and iron-reducing tests), antibacterial (microdilution method, against four human pathogenic bacteria) and anti-tyrosinase activities. Besides, their aromatic composition was determined by RP-HPLC. H. articulatum shoot extracts exhibited the strongest antioxidant activity and inhibited efficiently the growth of Salmonella enterica and Escherichia coli . P. scoparius and C. arabica inhibited slightly monophenolase, whereas H. articulatum was the most efficient inhibitor of diphenolase activity. Furthermore, H. articulatum exhibited the highest aromatic content (3.4 % DW), with dopamine as the major compound. These observations suggest that shoot extract of H. articulatum , and to a lesser extent of C. arabica , could be used as antioxidant, antibiotic as well as new natural skin lightening agents. Also, possible implication of aromatic compounds in anti-tyrosinase activity is discussed.

  3. [Mahalanobis distance based hyperspectral characteristic discrimination of leaves of different desert tree species].

    PubMed

    Lin, Hai-jun; Zhang, Hui-fang; Gao, Ya-qi; Li, Xia; Yang, Fan; Zhou, Yan-fei

    2014-12-01

    The hyperspectral reflectance of Populus euphratica, Tamarix hispida, Haloxylon ammodendron and Calligonum mongolicum in the lower reaches of Tarim River and Turpan Desert Botanical Garden was measured by using the HR-768 field-portable spectroradiometer. The method of continuum removal, first derivative reflectance and second derivative reflectance were used to deal with the original spectral data of four tree species. The method of Mahalanobis Distance was used to select the bands with significant differences in the original spectral data and transform spectral data to identify the different tree species. The progressive discrimination analyses were used to test the selective bands used to identify different tree species. The results showed that The Mahalanobis Distance method was an effective method in feature band extraction. The bands for identifying different tree species were most near-infrared bands. The recognition accuracy of four methods was 85%, 93.8%, 92.4% and 95.5% respectively. Spectrum transform could improve the recognition accuracy. The recognition accuracy of different research objects and different spectrum transform methods were different. The research provided evidence for desert tree species classification, monitoring biodiversity and the analysis of area in desert by using large scale remote sensing method.

  4. Integrated Population Pharmacokinetic Analysis of Rivaroxaban Across Multiple Patient Populations

    PubMed Central

    Zhang, Liping; Frede, Matthias; Kubitza, Dagmar; Mueck, Wolfgang; Schmidt, Stephan; Solms, Alexander; Yan, Xiaoyu; Garmann, Dirk

    2018-01-01

    The population pharmacokinetics (PK) of rivaroxaban have been evaluated in several population‐specific models. We developed an integrated population PK model using pooled data from 4,918 patients in 7 clinical trials across all approved indications. Effects of gender, age, and weight on apparent clearance (CL/F) and apparent volume of distribution (V/F), renal function, and comedication on CL/F, and relative bioavailability as a function of dose (F) were analyzed. Virtual subpopulations for exposure simulations were defined by age, creatinine clearance (CrCL) and body mass index (BMI). Rivaroxaban PK were adequately described by a one‐compartment disposition model with a first‐order absorption rate constant. Significant effects of CrCL, use of comedications, and study population on CL/F, age, weight, and gender on V/F, and dose on F were identified. CrCL had a modest influence on exposure, whereas age and BMI had a minor influence. The model was suitable to predict rivaroxaban exposure in patient subgroups of special interest. PMID:29660785

  5. Recovery Trends in Marine Mammal Populations

    PubMed Central

    Magera, Anna M.; Mills Flemming, Joanna E.; Kaschner, Kristin; Christensen, Line B.; Lotze, Heike K.

    2013-01-01

    Marine mammals have greatly benefitted from a shift from resource exploitation towards conservation. Often lauded as symbols of conservation success, some marine mammal populations have shown remarkable recoveries after severe depletions. Others have remained at low abundance levels, continued to decline, or become extinct or extirpated. Here we provide a quantitative assessment of (1) publicly available population-level abundance data for marine mammals worldwide, (2) abundance trends and recovery status, and (3) historic population decline and recent recovery. We compiled 182 population abundance time series for 47 species and identified major data gaps. In order to compare across the largest possible set of time series with varying data quality, quantity and frequency, we considered an increase in population abundance as evidence of recovery. Using robust log-linear regression over three generations, we were able to classify abundance trends for 92 spatially non-overlapping populations as Significantly Increasing (42%), Significantly Decreasing (10%), Non-Significant Change (28%) and Unknown (20%). Our results were comparable to IUCN classifications for equivalent species. Among different groupings, pinnipeds and other marine mammals (sirenians, polar bears and otters) showed the highest proportion of recovering populations, likely benefiting from relatively fast life histories and nearshore habitats that provided visibility and protective management measures. Recovery was less frequent among cetaceans, but more common in coastal than offshore populations. For marine mammals with available historical abundance estimates (n = 47), larger historical population declines were associated with low or variable recent recoveries so far. Overall, our results show that many formerly depleted marine mammal populations are recovering. However, data-deficient populations and those with decreasing and non-significant trends require attention. In particular, increased

  6. Marx's scientific theory of surplus population.

    PubMed

    Liu, Z

    1985-07-01

    This paper discusses Marx's scientific theory of surplus population in relation to the Malthusian theory of population. Marx establishes the principle that the existence of relative surplus population is determined by the immanent conditions of the mode of social production. Marx proves scientifically that the appearance of capitalist surplus population is not due to the abstract numerical ratio relation proposed by Mathus in which natural reproduction of humanity takes the geometric progression and the increase in the means of subsistence the arithmetic, but is the result of capitalist accumulation, the increase of the organic component of capital, the incessant increase in constant capital, and the relative decrease in the variable part of capital. Surplus population, according to Marx, cannot be compared with the surplus of the means of subsistence but with its condition of reproduction. Marx differentiates the surplus population into 2 kinds: the ancient population presses on the productive power, while modern productive power presses on population. In class society based on private ownership of the means of production, laborers can realize the integration with the means of production only under the condition that they provide the exploiters with surplus product; therefore, a certain amount of the laboring population are always turning into the relative surplus population. In the process of transition from the transitional to the modern type of population reproduction, there exists a traditional type of population characterized by a high birth rate, low mortality, and high natural growth rate. The situation in China is the result of the level of development of the productive forces and the corresponding underdevelopment of culture and education, but it is by no means the result of the effect of Malthus's "natural law" that population increases in a geometric progression.

  7. Population structure of two black Venezuelan populations studied through their mating structure and other related variables.

    PubMed

    Castro de Guerra, D; Arvelo, H; Pinto-Cisternas, J

    1999-01-01

    In order to obtain information about the population structure of two black Venezuelan populations with historical differences both in their origins and development, a variety of variables were utilized, especially on marital structure, including: frequency of surnames, isonymy, population genealogical consanguinity, multiple unions, and marital distances, all of which provided information and isolation, migration, endogamy, consanguinity, and patri-matrifocality. Results showed differences in the extent of isolation and endogamy, as well as differences in population structure, which can be directly related with historical conditions of each population. Results agree with those previously obtained with traditional genetic polymorphisms and with the historical information available. Thus, the usefulness of surnames for inferring about population structure is supported, as well as the usefulness of historical information for explaining genetic diversity.

  8. Measuring populations to improve vaccination coverage

    NASA Astrophysics Data System (ADS)

    Bharti, Nita; Djibo, Ali; Tatem, Andrew J.; Grenfell, Bryan T.; Ferrari, Matthew J.

    2016-10-01

    In low-income settings, vaccination campaigns supplement routine immunization but often fail to achieve coverage goals due to uncertainty about target population size and distribution. Accurate, updated estimates of target populations are rare but critical; short-term fluctuations can greatly impact population size and susceptibility. We use satellite imagery to quantify population fluctuations and the coverage achieved by a measles outbreak response vaccination campaign in urban Niger and compare campaign estimates to measurements from a post-campaign survey. Vaccine coverage was overestimated because the campaign underestimated resident numbers and seasonal migration further increased the target population. We combine satellite-derived measurements of fluctuations in population distribution with high-resolution measles case reports to develop a dynamic model that illustrates the potential improvement in vaccination campaign coverage if planners account for predictable population fluctuations. Satellite imagery can improve retrospective estimates of vaccination campaign impact and future campaign planning by synchronizing interventions with predictable population fluxes.

  9. Population Health Management for Older Adults

    PubMed Central

    Tkatch, Rifky; Musich, Shirley; MacLeod, Stephanie; Alsgaard, Kathleen; Hawkins, Kevin; Yeh, Charlotte S.

    2016-01-01

    Background: The older adult population is expanding, living longer, with multiple chronic conditions. Understanding and managing their needs over time is an integral part of defining successful aging. Population health is used to describe the measurement and health outcomes of a population. Objectives: To define population health as applied to older adults, summarize lessons learned from current research, and identify potential interventions designed to promote successful aging and improved health for this population. Method: Online search engines were utilized to identify research on population health and health interventions for older adults. Results: Population health management (PHM) is one strategy to promote the health and well-being of target populations. Interventions promoting health across a continuum tend to be disease, risk, or health behavior specific rather than encompassing a global concept of health. Conclusion: Many existing interventions for older adults are simply research based with limited generalizability; as such, further work in this area is warranted. PMID:28680938

  10. Measuring populations to improve vaccination coverage

    PubMed Central

    Bharti, Nita; Djibo, Ali; Tatem, Andrew J.; Grenfell, Bryan T.; Ferrari, Matthew J.

    2016-01-01

    In low-income settings, vaccination campaigns supplement routine immunization but often fail to achieve coverage goals due to uncertainty about target population size and distribution. Accurate, updated estimates of target populations are rare but critical; short-term fluctuations can greatly impact population size and susceptibility. We use satellite imagery to quantify population fluctuations and the coverage achieved by a measles outbreak response vaccination campaign in urban Niger and compare campaign estimates to measurements from a post-campaign survey. Vaccine coverage was overestimated because the campaign underestimated resident numbers and seasonal migration further increased the target population. We combine satellite-derived measurements of fluctuations in population distribution with high-resolution measles case reports to develop a dynamic model that illustrates the potential improvement in vaccination campaign coverage if planners account for predictable population fluctuations. Satellite imagery can improve retrospective estimates of vaccination campaign impact and future campaign planning by synchronizing interventions with predictable population fluxes. PMID:27703191

  11. Population education in the schools.

    PubMed

    Sherris, J D; Quillin, W F

    1982-01-01

    Formal population education is designed to teach children in school about basic population issues and, in many cases, to encourage them eventually to have smaller families. Some programs include specific units on human reproduction and family planning, while others do not. National population education programs began during the 1970s in about a dozen countries, mainly in Asia. These include Bangladesh, India, Indonesia, South Korea, Malaysia, the Philippines, Sierra Leone, Sri Lanka, Singapore, Thailand, Egypt, Tunisia, and El Salvador. A strong case can be made for including an important contemporary issue like population in the school curriculum. Nevertheless, educational innovation is a difficult and long-term process. As a rule, it takes 5 to 10 years before new material can be fully incorporated in a school curriculum. Curriculum changes must be carefully planned, thousands of teachers trained, and appropriate materials prepared for classroom use. Moreover, differences of opinion over the need, acceptability, goals, content, methods, and other aspects of population education have held back programs in some countries. Where population education programs have been implemented, student knowledge of population issues increases, but it is not yet clear whether in-school education has a measurable impact on fertility-related attitudes or behavior.

  12. How Large Asexual Populations Adapt

    NASA Astrophysics Data System (ADS)

    Desai, Michael

    2007-03-01

    We often think of beneficial mutations as being rare, and of adaptation as a sequence of selected substitutions: a beneficial mutation occurs, spreads through a population in a selective sweep, then later another beneficial mutation occurs, and so on. This simple picture is the basis for much of our intuition about adaptive evolution, and underlies a number of practical techniques for analyzing sequence data. Yet many large and mostly asexual populations -- including a wide variety of unicellular organisms and viruses -- live in a very different world. In these populations, beneficial mutations are common, and frequently interfere or cooperate with one another as they all attempt to sweep simultaneously. This radically changes the way these populations adapt: rather than an orderly sequence of selective sweeps, evolution is a constant swarm of competing and interfering mutations. I will describe some aspects of these dynamics, including why large asexual populations cannot evolve very quickly and the character of the diversity they maintain. I will explain how this changes our expectations of sequence data, how sex can help a population adapt, and the potential role of ``mutator'' phenotypes with abnormally high mutation rates. Finally, I will discuss comparisons of these predictions with evolution experiments in laboratory yeast populations.

  13. Can human populations be stabilized?

    NASA Astrophysics Data System (ADS)

    Warren, Stephen G.

    2015-02-01

    Historical examples of demographic change, in China, Italy, Nigeria, Utah, Easter Island, and elsewhere, together with simple mathematics and biological principles, show that stabilizing world population before it is limited by food supply will be more difficult than is generally appreciated. United Nations population projections are wrong because they assume, in spite of the absence of necessary feedbacks, that all nations will converge rapidly to replacement-level fertility and thereafter remain at that level. Education of women and provision of contraceptives have caused dramatic reductions in fertility, but many groups, including some that are well-educated, maintain high fertility. Small groups with persistent high fertility can grow to supplant low-fertility groups, resulting in continued growth of the total population. The global average fertility rate could rise even if each country's fertility rate is falling. In some low-fertility European countries where deaths exceed births, the population continues to grow because of immigration. Producing more than two offspring is normal for all animal species with stable populations because their populations are limited by resources or predation rather than birth control. It may therefore be appropriate to view the growth of human population as the result not of excess fertility but rather of excess food.

  14. Population Redistribution in the Midwest.

    ERIC Educational Resources Information Center

    Roseman, Curtis C., Ed.; And Others

    The nine chapters in the book focus on the 1970s' metropolitan to nonmetropolitan migration stream and address both population patterns and processes and the impacts and policy issues associated with the resulting population redistribution in the Midwest. Peter A. Morrison places the Midwest in the national context of changing population structure…

  15. Population Education Documents, Reprint Series.

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific, and Cultural Organization, Bangkok (Thailand). Regional Office for Education in Asia and Oceania.

    This publication contains reprints of five documents that were either published in foreign journals or released in limited numbers by author or publisher. The papers are all concerned with population education, but deal more specifically with the role of population and the schools. Among the topics discussed are population education and the school…

  16. The Education of Population Scientists.

    ERIC Educational Resources Information Center

    Malcolm, Janet M.; Cargille, Charles M.

    Population science, a combination of natural science, social science, and management science, deals with the phenomena associated with the human population size. Subjects include the rates of change of the sizes of the various subsets of the human population, the causes and results of those changes, the societal pressures for control of population…

  17. 1974 is World Population Year.

    ERIC Educational Resources Information Center

    Asian Population Programme News, 1974

    1974-01-01

    This publication is a special issue of the Asian Population Programme News. This particular publication is concerned with population year 1974. Highlights from the thirtieth session of the Economic Commission for Asia and the Far East (ECAFE) are presented. World, regional, and country population news are included in separate sections. A listing…

  18. Population Policy, 1984.

    PubMed

    1988-01-01

    This summary of Hungary's Population Policy of 1984 states that the primary objectives of the policy are 1) reducing the speed of population decline, 2) slowing population growth and achieving a more favorable age distribution, and 3) avoiding the emergence of new major peaks in birth numbers. This new policy gives equal importance to factors which influence fertility and those which influence mortality. The need to integrate population policy into socioeconomic planning is also reflected in the formal time frames offered by the policy. The policy stresses the importance of education and communication to influence public attitudes towards healthy lifestyles and family life. The need for demographic research is recognized as is the importance of public opinion research in developing appropriate actions to meet the stated goals. Instead of advocating a desired family size, the new policy seeks to establish conditions which make it easier for a family to achieve its desired fertility; for example, establishing a maternity fee as a fixed proportion of a mother's previous income for mothers who stay at home to raise their children until a certain age. The development of these measures depends upon analysis of labor market policies, the national budget, and the fertility of age cohorts of women.

  19. Information in Support of Population Activities.

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific, and Cultural Organization, Paris (France).

    As part of UNESCO's World Population Year, information services in support of population programs are explained and listed. The information system of the International Planned Parenthood Federation is described and the management of population literature discussed. Information needs of population workers and special aspects of the training and…

  20. 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.

  1. Population Dynamics of Genetic Regulatory Networks

    NASA Astrophysics Data System (ADS)

    Braun, Erez

    2005-03-01

    Unlike common objects in physics, a biological cell processes information. The cell interprets its genome and transforms the genomic information content, through the action of genetic regulatory networks, into proteins which in turn dictate its metabolism, functionality and morphology. Understanding the dynamics of a population of biological cells presents a unique challenge. It requires to link the intracellular dynamics of gene regulation, through the mechanism of cell division, to the level of the population. We present experiments studying adaptive dynamics of populations of genetically homogeneous microorganisms (yeast), grown for long durations under steady conditions. We focus on population dynamics that do not involve random genetic mutations. Our experiments follow the long-term dynamics of the population distributions and allow to quantify the correlations among generations. We focus on three interconnected issues: adaptation of genetically homogeneous populations following environmental changes, selection processes on the population and population variability and expression distributions. We show that while the population exhibits specific short-term responses to environmental inputs, it eventually adapts to a robust steady-state, largely independent of external conditions. Cycles of medium-switch show that the adapted state is imprinted in the population and that this memory is maintained for many generations. To further study population adaptation, we utilize the process of gene recruitment whereby a gene naturally regulated by a specific promoter is placed under a different regulatory system. This naturally occurring process has been recognized as a major driving force in evolution. We have recruited an essential gene to a foreign regulatory network and followed the population long-term dynamics. Rewiring of the regulatory network allows us to expose their complex dynamics and phase space structure.

  2. Population control in symbiotic corals

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

    Falkowski, P.G.; Dubinsky, Z.; Muscatine, L.

    1993-10-01

    Stability in symbiotic association requires control of population growth between symbionts. The population density of zooxanthellae per unit surface area of most symbiotic corals is remarkably consistant. How is the population density of zooxanthellae maintained and what happens to the symbiotic association if the balance between algae and host is perturbed. The answers to these question, examined in this paper, provide a framework for understanding how the size of the component populations is controlled in symbiotic associations. The topic areas covered include the following: carbon economy in a symbiotic coral; effects of nutrient enrichment; the chemostat model of population control;more » the effects of exposure to ammonium levels. Ammonium ions and organic materials are the factors which maintain the density of zooxanthellae. 32 refs., 5 figs.« less

  3. PBPK and population modelling to interpret urine cadmium concentrations of the French population

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

    Béchaux, Camille, E-mail: Camille.bechaux@anses.fr; Bodin, Laurent; Clémençon, Stéphan

    As cadmium accumulates mainly in kidney, urinary concentrations are considered as relevant data to assess the risk related to cadmium. The French Nutrition and Health Survey (ENNS) recorded the concentration of cadmium in the urine of the French population. However, as with all biomonitoring data, it needs to be linked to external exposure for it to be interpreted in term of sources of exposure and for risk management purposes. The objective of this work is thus to interpret the cadmium biomonitoring data of the French population in terms of dietary and cigarette smoke exposures. Dietary and smoking habits recorded inmore » the ENNS study were combined with contamination levels in food and cigarettes to assess individual exposures. A PBPK model was used in a Bayesian population model to link this external exposure with the measured urinary concentrations. In this model, the level of the past exposure was corrected thanks to a scaling function which account for a trend in the French dietary exposure. It resulted in a modelling which was able to explain the current urinary concentrations measured in the French population through current and past exposure levels. Risk related to cadmium exposure in the general French population was then assessed from external and internal critical values corresponding to kidney effects. The model was also applied to predict the possible urinary concentrations of the French population in 2030 assuming there will be no more changes in the exposures levels. This scenario leads to significantly lower concentrations and consequently lower related risk. - Highlights: • Interpretation of urine cadmium concentrations in France • PBPK and Bayesian population modelling of cadmium exposure • Assessment of the historic time-trend of the cadmium exposure in France • Risk assessment from current and future external and internal exposure.« less

  4. Psychology and Population: An Overview.

    ERIC Educational Resources Information Center

    Fawcett, James T.

    Psychology and Population is defined as the study of individual dispositions and behavior that affect the size, structure and dispersion of the population, and the way in which acts of individuals enter into the dynamics of population change. Even this definition was viewed as inadequate, ignoring, as it does, the reciprocal effect of population…

  5. Population and Development [Issue Packet].

    ERIC Educational Resources Information Center

    American Freedom from Hunger Foundation, Washington, DC.

    A variety of informational materials is compiled in this issue packet concentrating on population and development. The materials have been assembled to understand the issues associated with the facts of the world's population and to try to invent new forms of action and thought necessary to find the possibilities hidden in the population issue.…

  6. 45 CFR 1356.81 - Reporting population.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 45 Public Welfare 4 2012-10-01 2012-10-01 false Reporting population. 1356.81 Section 1356.81... § 1356.81 Reporting population. The reporting population is comprised of all youth in the following categories: (a) Served population. Each youth who receives an independent living service paid for or provided...

  7. 45 CFR 1356.81 - Reporting population.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 45 Public Welfare 4 2013-10-01 2013-10-01 false Reporting population. 1356.81 Section 1356.81... § 1356.81 Reporting population. The reporting population is comprised of all youth in the following categories: (a) Served population. Each youth who receives an independent living service paid for or provided...

  8. 45 CFR 1356.81 - Reporting population.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 4 2014-10-01 2014-10-01 false Reporting population. 1356.81 Section 1356.81... § 1356.81 Reporting population. The reporting population is comprised of all youth in the following categories: (a) Served population. Each youth who receives an independent living service paid for or provided...

  9. The Distribution of Southern Black Population.

    ERIC Educational Resources Information Center

    Tucker, Jack; Lee, Everett S.

    Between 1960 and 1970, the black population of the southern United States increased only four percent by comparison with a national increase in black population of twenty percent. Considering the many factors involved in population redistribution, this report compares southern and overall national trends in black population and analyzes the…

  10. Genetic diversity and population structure in contemporary house sparrow populations along an urbanization gradient

    PubMed Central

    Vangestel, C; Mergeay, J; Dawson, D A; Callens, T; Vandomme, V; Lens, L

    2012-01-01

    House sparrow (Passer domesticus) populations have suffered major declines in urban as well as rural areas, while remaining relatively stable in suburban ones. Yet, to date no exhaustive attempt has been made to examine how, and to what extent, spatial variation in population demography is reflected in genetic population structuring along contemporary urbanization gradients. Here we use putatively neutral microsatellite loci to study if and how genetic variation can be partitioned in a hierarchical way among different urbanization classes. Principal coordinate analyses did not support the hypothesis that urban/suburban and rural populations comprise two distinct genetic clusters. Comparison of FST values at different hierarchical scales revealed drift as an important force of population differentiation. Redundancy analyses revealed that genetic structure was strongly affected by both spatial variation and level of urbanization. The results shown here can be used as baseline information for future genetic monitoring programmes and provide additional insights into contemporary house sparrow dynamics along urbanization gradients. PMID:22588131

  11. Genetic diversity and population structure in contemporary house sparrow populations along an urbanization gradient.

    PubMed

    Vangestel, C; Mergeay, J; Dawson, D A; Callens, T; Vandomme, V; Lens, L

    2012-09-01

    House sparrow (Passer domesticus) populations have suffered major declines in urban as well as rural areas, while remaining relatively stable in suburban ones. Yet, to date no exhaustive attempt has been made to examine how, and to what extent, spatial variation in population demography is reflected in genetic population structuring along contemporary urbanization gradients. Here we use putatively neutral microsatellite loci to study if and how genetic variation can be partitioned in a hierarchical way among different urbanization classes. Principal coordinate analyses did not support the hypothesis that urban/suburban and rural populations comprise two distinct genetic clusters. Comparison of FST values at different hierarchical scales revealed drift as an important force of population differentiation. Redundancy analyses revealed that genetic structure was strongly affected by both spatial variation and level of urbanization. The results shown here can be used as baseline information for future genetic monitoring programmes and provide additional insights into contemporary house sparrow dynamics along urbanization gradients.

  12. Population Profile of the United States: 1974. Current Population Reports, Series P-20, No. 279.

    ERIC Educational Resources Information Center

    Glick, Paul C., Ed.

    Statistics on population growth, social characteristics, population distribution, employment and income, and ethnic groups are presented in this report. Among the highlights of the report are the following findings: the population grew by three-fourths of one percent during 1974, a slightly higher rate than 1973 but substantially lower than the…

  13. Pronounced fixation, strong population differentiation and complex population history in the Canary Islands blue tit subspecies complex.

    PubMed

    Hansson, Bengt; Ljungqvist, Marcus; Illera, Juan-Carlos; Kvist, Laura

    2014-01-01

    Evolutionary molecular studies of island radiations may lead to insights in the role of vicariance, founder events, population size and drift in the processes of population differentiation. We evaluate the degree of population genetic differentiation and fixation of the Canary Islands blue tit subspecies complex using microsatellite markers and aim to get insights in the population history using coalescence based methods. The Canary Island populations were strongly genetically differentiated and had reduced diversity with pronounced fixation including many private alleles. In population structure models, the relationship between the central island populations (La Gomera, Tenerife and Gran Canaria) and El Hierro was difficult to disentangle whereas the two European populations showed consistent clustering, the two eastern islands (Fuerteventura and Lanzarote) and Morocco weak clustering, and La Palma a consistent unique lineage. Coalescence based models suggested that the European mainland forms an outgroup to the Afrocanarian population, a split between the western island group (La Palma and El Hierro) and the central island group, and recent splits between the three central islands, and between the two eastern islands and Morocco, respectively. It is clear that strong genetic drift and low level of concurrent gene flow among populations have shaped complex allelic patterns of fixation and skewed frequencies over the archipelago. However, understanding the population history remains challenging; in particular, the pattern of extreme divergence with low genetic diversity and yet unique genetic material in the Canary Island system requires an explanation. A potential scenario is population contractions of a historically large and genetically variable Afrocanarian population, with vicariance and drift following in the wake. The suggestion from sequence-based analyses of a Pleistocene extinction of a substantial part of North Africa and a Pleistocene/Holocene eastward

  14. Pronounced Fixation, Strong Population Differentiation and Complex Population History in the Canary Islands Blue Tit Subspecies Complex

    PubMed Central

    Hansson, Bengt; Ljungqvist, Marcus; Illera, Juan-Carlos; Kvist, Laura

    2014-01-01

    Evolutionary molecular studies of island radiations may lead to insights in the role of vicariance, founder events, population size and drift in the processes of population differentiation. We evaluate the degree of population genetic differentiation and fixation of the Canary Islands blue tit subspecies complex using microsatellite markers and aim to get insights in the population history using coalescence based methods. The Canary Island populations were strongly genetically differentiated and had reduced diversity with pronounced fixation including many private alleles. In population structure models, the relationship between the central island populations (La Gomera, Tenerife and Gran Canaria) and El Hierro was difficult to disentangle whereas the two European populations showed consistent clustering, the two eastern islands (Fuerteventura and Lanzarote) and Morocco weak clustering, and La Palma a consistent unique lineage. Coalescence based models suggested that the European mainland forms an outgroup to the Afrocanarian population, a split between the western island group (La Palma and El Hierro) and the central island group, and recent splits between the three central islands, and between the two eastern islands and Morocco, respectively. It is clear that strong genetic drift and low level of concurrent gene flow among populations have shaped complex allelic patterns of fixation and skewed frequencies over the archipelago. However, understanding the population history remains challenging; in particular, the pattern of extreme divergence with low genetic diversity and yet unique genetic material in the Canary Island system requires an explanation. A potential scenario is population contractions of a historically large and genetically variable Afrocanarian population, with vicariance and drift following in the wake. The suggestion from sequence-based analyses of a Pleistocene extinction of a substantial part of North Africa and a Pleistocene/Holocene eastward

  15. Population Trends and Prospects.

    ERIC Educational Resources Information Center

    Mauldin, W. Parker

    1980-01-01

    Future trends in population are described as they relate to developed and developing nations. It is suggested that for the next 20 years there will be a decrease in population growth rates for all areas of the world except Africa. (Author/SA)

  16. Conservation genetics of managed ungulate populations

    USGS Publications Warehouse

    Scribner, Kim T.

    1993-01-01

    Natural populations of many species are increasingly impacted by human activities. Perturbations are particularly pronunced for large ungulates due in part to sport and commercial harvest, to reductions and fragmentation of native habitat, and as the result of reintroductions. These perturbations affect population size, sex and age composition, and population breeding structure, and as a consequence affect the levels and partitioning of genetic variation. Three case histories highlighting long-term ecological genetic research on mule deer Odocoileus hemionus (Rafinesque, 1817), white-tailed deer O. virginianus (Zimmermann, 1780), and Alpine ibex Capra i. ibex Linnaeus, 1758 are presented. Joint examinations of population ecological and genetic data from several populations of each species reveal: (1) that populations are not in genetic equilibrium, but that allele frequencies and heterozygosity change dramatically over time and among cohorts produced in successive years, (2) populations are genetically structured over short and large geographic distances reflecting local breeding structure and patterns of gene flow, respectively; however, this structure is quite dynamic over time, due in part to population exploitation, and (3) restocking programs are often undertaken with small numbers of founding individuals resulting in dramatic declines in levels of genetic variability and increasing levels of genetic differentiation among populations due to genetic drift. Genetic characteristics have and will continue to provide valuable indirect sources of information relating enviromental and human perturbations to changes in population processes.

  17. Microbial diversity--insights from population genetics.

    PubMed

    Mes, Ted H M

    2008-01-01

    Although many environmental microbial populations are large and genetically diverse, both the level of diversity and the extent to which it is ecologically relevant remain enigmatic. Because the effective (or long-term) population size, N(e), is one of the parameters that determines population genetic diversity, tests and simulations that assume selectively neutral mutations may help to identify the processes that have shaped microbial diversity. Using ecologically important genes, tests of selective neutrality suggest that adaptive as well as non-adaptive types of selection act and that departure from neutrality may be widespread or restricted to small groups of genotypes. Population genetic simulations using population sizes between 10(3) and 10(7) suggest extremely high levels of microbial diversity in environments that sustain large populations. However, census and effective population sizes may differ considerably, and because we know nothing of the evolutionary history of environmental microbial populations, we also have no idea what N(e) of environmental populations is. On the one hand, this reflects our ignorance of the microbial world. On the other hand, the tests and simulations illustrate interactions between microbial diversity and microbial population genetics that should inform our thinking in microbial ecology. Because of the different views on microbial diversity across these disciplines, such interactions are crucial if we are to understand the role of genes in microbial communities.

  18. Strategy selection in structured populations.

    PubMed

    Tarnita, Corina E; Ohtsuki, Hisashi; Antal, Tibor; Fu, Feng; Nowak, Martin A

    2009-08-07

    Evolutionary game theory studies frequency dependent selection. The fitness of a strategy is not constant, but depends on the relative frequencies of strategies in the population. This type of evolutionary dynamics occurs in many settings of ecology, infectious disease dynamics, animal behavior and social interactions of humans. Traditionally evolutionary game dynamics are studied in well-mixed populations, where the interaction between any two individuals is equally likely. There have also been several approaches to study evolutionary games in structured populations. In this paper we present a simple result that holds for a large variety of population structures. We consider the game between two strategies, A and B, described by the payoff matrix(abcd). We study a mutation and selection process. For weak selection strategy A is favored over B if and only if sigma a+b>c+sigma d. This means the effect of population structure on strategy selection can be described by a single parameter, sigma. We present the values of sigma for various examples including the well-mixed population, games on graphs, games in phenotype space and games on sets. We give a proof for the existence of such a sigma, which holds for all population structures and update rules that have certain (natural) properties. We assume weak selection, but allow any mutation rate. We discuss the relationship between sigma and the critical benefit to cost ratio for the evolution of cooperation. The single parameter, sigma, allows us to quantify the ability of a population structure to promote the evolution of cooperation or to choose efficient equilibria in coordination games.

  19. Population Genomics of Daphnia pulex

    PubMed Central

    Lynch, Michael; Gutenkunst, Ryan; Ackerman, Matthew; Spitze, Ken; Ye, Zhiqiang; Maruki, Takahiro; Jia, Zhiyuan

    2017-01-01

    Using data from 83 isolates from a single population, the population genomics of the microcrustacean Daphnia pulex are described and compared to current knowledge for the only other well-studied invertebrate, Drosophila melanogaster. These two species are quite similar with respect to effective population sizes and mutation rates, although some features of recombination appear to be different, with linkage disequilibrium being elevated at short (<100 bp) distances in D. melanogaster and at long distances in D. pulex. The study population adheres closely to the expectations under Hardy–Weinberg equilibrium, and reflects a past population history of no more than a twofold range of variation in effective population size. Fourfold redundant silent sites and a restricted region of intronic sites appear to evolve in a nearly neutral fashion, providing a powerful tool for population genetic analyses. Amino acid replacement sites are predominantly under strong purifying selection, as are a large fraction of sites in UTRs and intergenic regions, but the majority of SNPs at such sites that rise to frequencies >0.05 appear to evolve in a nearly neutral fashion. All forms of genomic sites (including replacement sites within codons, and intergenic and UTR regions) appear to be experiencing an ∼2× higher level of selection scaled to the power of drift in D. melanogaster, but this may in part be a consequence of recent demographic changes. These results establish D. pulex as an excellent system for future work on the evolutionary genomics of natural populations. PMID:27932545

  20. Multidisciplinary population monitoring when demographic data are sparse: a case study of remote trout populations

    PubMed Central

    Fraser, Dylan J; Calvert, Anna M; Bernatchez, Louis; Coon, Andrew

    2013-01-01

    The potential of genetic, genomic, and phenotypic metrics for monitoring population trends may be especially high in isolated regions, where traditional demographic monitoring is logistically difficult and only sporadic sampling is possible. This potential, however, is relatively underexplored empirically. Over eleven years, we assessed several such metrics along with traditional ecological knowledge and catch data in a socioeconomically important trout species occupying a large, remote lake. The data revealed largely stable characteristics in two populations over 2–3 generations, but possible contemporary changes in a third population. These potential shifts were suggested by reduced catch rates, reduced body size, and changes in selection implied at one gene-associated single nucleotide polymorphism. A demographic decline in this population, however, was ambiguously supported, based on the apparent lack of temporal change in effective population size, and corresponding traditional knowledge suggesting little change in catch. We illustrate how the pluralistic approach employed has practicality for setting future monitoring efforts of these populations, by guiding monitoring priorities according to the relative merits of different metrics and availability of resources. Our study also considers some advantages and disadvantages to adopting a pluralistic approach to population monitoring where demographic data are not easily obtained. PMID:24455128

  1. [Population changes and social welfare tasks].

    PubMed

    Lee, H K

    1985-07-01

    Efforts to control population growth made during the last 20 years are expected to maintain a stable population in the future. We cannot limit our concern to the control of population growth but must consider the social welfare task in the aspect of population stability. It is not because population changes set limits to artificial control, but because the order of population changes presents a desirable sign for low fertility. Another important concern is to pay attention to how to make human beings already born and those to be born in the future enjoy their quality of life. Socioeconomic stability requires economic stabilization to meet basic essential needs. Changes in population structure, along with the quantitative growth of population, make changes in patterns of social welfare demands. When the pyramid type of population structure becomes changed to the bell or pot type of population structure, changes in education and employment as well as changes in problems of the aged and medical demands must be made. On the other hand, population changes accompany value changes in the process of modernization of society. These multiple social changes bring about a value of individualism and a nuclear family norm, and an enlargement of women's social participation which, in turn, can cause family problems. At the same time, social deviations and failures may be increased in the industrial society, and, thus, welfare countermeasures have to be taken. In this respect, the base of social welfare for meeting basic demands must be formed not in the past, narrow sense but in the long range and multisided aspects.

  2. Educational Attainment in the United States: 2003. Population Characteristics. Current Population Reports. P20-550

    ERIC Educational Resources Information Center

    Stoops, Nicole

    2004-01-01

    This report provides information on basic educational trends and attainment levels across many segments of the population. The findings are based on data collected in the 2003 Annual Social and Economic Supplement (ASEC) to the Current Population Survey (CPS) and refer to the population 25 years and over unless otherwise specified. The population…

  3. Population-Level Effect of Cholera Vaccine on Displaced Populations, South Sudan, 2014.

    PubMed

    Azman, Andrew S; Rumunu, John; Abubakar, Abdinasir; West, Haley; Ciglenecki, Iza; Helderman, Trina; Wamala, Joseph Francis; Vázquez, Olimpia de la Rosa; Perea, William; Sack, David A; Legros, Dominique; Martin, Stephen; Lessler, Justin; Luquero, Francisco J

    2016-06-01

    Following mass population displacements in South Sudan, preventive cholera vaccination campaigns were conducted in displaced persons camps before a 2014 cholera outbreak. We compare cholera transmission in vaccinated and unvaccinated areas and show vaccination likely halted transmission within vaccinated areas, illustrating the potential for oral cholera vaccine to stop cholera transmission in vulnerable populations.

  4. Australia and international treaties: population.

    PubMed

    Hugo, G

    1995-05-01

    "The separation of environmental and population issues globally is reflected in the fact that the setting of international agendas to tackle them was for all intents and purposes undertaken at separate international meetings--the Earth Summit in Rio de Janeiro in 1992 and the International Population Conference in Cairo in 1994. This paper presents an overview of Australia's international involvement in population issues and suggests that until recently Australia had played a minor political role in international population initiatives primarily, and perhaps ironically, because it has been a world leader in demographic research and teaching for several decades." excerpt

  5. 1984 Population Trends for Washington State.

    ERIC Educational Resources Information Center

    Washington State Office of Financial Management, Olympia.

    As of April 1, 1984, Washington's population was estimated at 4,328,100, an increase of 43,000 over last year's population. This report provides data pertaining to the: official April 1, 1984 population and housing estimates for cities, towns, and counties and components of population change. The following special reports are also presented:…

  6. Bangladesh. Population education programme reviewed.

    PubMed

    1995-01-01

    The UNFPA (UN Population Fund)-funded population education program was reviewed last November 1994 in order to identify the emerging needs and requirements as well as chart the future directions of the program. The review was undertaken with the assistance of the CST SAWA Adviser on Population Education, Dr. D.M. de Rebello. Comprehensive literature review, and intensive discussions with government functionaries, educationists, teachers, students, UNFPA country director and staff and concerned officials of the World Bank and other UN agencies involved in the program served as the modalities for the review. The review looked into the current status of the school education sector and assessed the present progress of the population education program vis-a-vis its objectives and achievements. It also analyzed the issues and constraints in relation to institutionalization of the program, capacity building and integration of population education in curriculum and textbooks. Among the many recommendations, the review proposed further building up of national capacities at various levels; development of teaching/learning materials and textbooks for the new sectors; and intensification of good quality teacher education. Institutionalization of population education in the formal school system up to grade 12 and in technical and vocational education as well as the madrasah system and the introduction of population education in the Mass Non-formal Education Program were also proposed. full text

  7. A population search filter for hard-to-reach populations increased search efficiency for a systematic review.

    PubMed

    Cooper, Chris; Levay, Paul; Lorenc, Theo; Craig, Gillian M

    2014-05-01

    This article discusses how hard-to-reach population groups were conceptualized into a search filter. The objectives of this article were to (1) discuss how the authors designed a multistranded population search filter and (2) retrospectively test the effectiveness of the search filter in capturing all relevant populations (eg, homeless people, immigrants, substance misusers) in a public health systematic review. Systematic and retrospective analysis via a case study. Retrospective analysis of the search filter was conducted by comparing the MEDLINE search results retrieved without using the search filter against those retrieved with the search filter. A total of 5,465 additional results from the unfiltered search were screened to the same criteria as the filtered search. No additional populations were identified in the unfiltered sample. The search filter reduced the volume of MEDLINE hits to screen by 64%, with no impact on inclusion of populations. The results demonstrate the effectiveness of the filter in capturing all relevant UK populations for the review. This suggests that well-planned search filters can be written for reviews that analyze imprecisely defined population groups. This filter could be used in topic areas of associated comorbidities, for rapid clinical searches, or for investigating hard-to-reach populations. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. Ancestral populations perform better in a novel environment: domestication of medfly populations from five global regions

    PubMed Central

    Diamantidis, Alexandros D.; Carey, James R.; Nakas, Christos T.; Papadopoulos, Nikos T.

    2010-01-01

    Geographically isolated populations of a species may differ in several aspects of life-history, morphology, behavior, and genetic structure as a result of adaptation in ecologically diverse habitats. We used a global invasive species, the Mediterranean fruit fly to investigate, whether adaptation to a novel environment differs among geographically isolated populations that vary in major life history components such as life span and reproduction. We used wild populations from five global regions (Kenya, Hawaii, Guatemala, Portugal, and Greece). Adult demographic traits were monitored in F2, F5, F7 and F9 generations in captivity. Although domestication in constant laboratory conditions had a different effect on the mortality and reproductive rates of the different populations, a general trend of decreasing life span and age of first reproduction was observed for most medfly populations tested. However, taking into account longevity of both sexes, age-specific reproductive schedules, and average reproductive rates we found that the ancestral Kenyan population kept the above life history traits stable during domestication compared to the other populations tested. These findings provide important insights in the life-history evolution of this model species, and suggest that ancestral medfly populations perform better than the derived – invasive ones in a novel environment. PMID:21278856

  9. Quasi-extinction risk and population targets for the Eastern, migratory population of monarch butterflies (Danaus plexippus)

    USGS Publications Warehouse

    Semmens, Brice X.; Semmens, Darius J.; Thogmartin, Wayne E.; Wiederholt, Ruscena; Lopez-Hoffman, Laura; Diffendorfer, James E.; Pleasants, John M.; Oberhauser, Karen S.; Taylor, Orley R.

    2016-01-01

    The Eastern, migratory population of monarch butterflies (Danaus plexippus), an iconic North American insect, has declined by ~80% over the last decade. The monarch’s multi-generational migration between overwintering grounds in central Mexico and the summer breeding grounds in the northern U.S. and southern Canada is celebrated in all three countries and creates shared management responsibilities across North America. Here we present a novel Bayesian multivariate auto-regressive state-space model to assess quasi-extinction risk and aid in the establishment of a target population size for monarch conservation planning. We find that, given a range of plausible quasi-extinction thresholds, the population has a substantial probability of quasi-extinction, from 11–57% over 20 years, although uncertainty in these estimates is large. Exceptionally high population stochasticity, declining numbers, and a small current population size act in concert to drive this risk. An approximately 5-fold increase of the monarch population size (relative to the winter of 2014–15) is necessary to halve the current risk of quasi-extinction across all thresholds considered. Conserving the monarch migration thus requires active management to reverse population declines, and the establishment of an ambitious target population size goal to buffer against future environmentally driven variability.

  10. Dimensions of global population projections: what do we know about future population trends and structures?

    PubMed Central

    Lutz, Wolfgang; KC, Samir

    2010-01-01

    The total size of the world population is likely to increase from its current 7 billion to 8–10 billion by 2050. This uncertainty is because of unknown future fertility and mortality trends in different parts of the world. But the young age structure of the population and the fact that in much of Africa and Western Asia, fertility is still very high makes an increase by at least one more billion almost certain. Virtually, all the increase will happen in the developing world. For the second half of the century, population stabilization and the onset of a decline are likely. In addition to the future size of the population, its distribution by age, sex, level of educational attainment and place of residence are of specific importance for studying future food security. The paper provides a detailed discussion of different relevant dimensions in population projections and an evaluation of the methods and assumptions used in current global population projections and in particular those produced by the United Nations and by IIASA. PMID:20713384

  11. Population-dependent effects of ocean acidification.

    PubMed

    Wood, Hannah L; Sundell, Kristina; Almroth, Bethanie Carney; Sköld, Helén Nilsson; Eriksson, Susanne P

    2016-04-13

    Elevated carbon dioxide levels and the resultant ocean acidification (OA) are changing the abiotic conditions of the oceans at a greater rate than ever before and placing pressure on marine species. Understanding the response of marine fauna to this change is critical for understanding the effects of OA. Population-level variation in OA tolerance is highly relevant and important in the determination of ecosystem resilience and persistence, but has received little focus to date. In this study, whether OA has the same biological consequences in high-salinity-acclimated population versus a low-salinity-acclimated population of the same species was investigated in the marine isopod Idotea balthica.The populations were found to have physiologically different responses to OA. While survival rate was similar between the two study populations at a future CO2 level of 1000 ppm, and both populations showed increased oxidative stress, the metabolic rate and osmoregulatory activity differed significantly between the two populations. The results of this study demonstrate that the physiological response to OA of populations from different salinities can vary. Population-level variation and the environment provenance of individuals used in OA experiments should be taken into account for the evaluation and prediction of climate change effects. © 2016 The Author(s).

  12. Population-dependent effects of ocean acidification

    PubMed Central

    Wood, Hannah L.; Sundell, Kristina; Almroth, Bethanie Carney; Sköld, Helén Nilsson; Eriksson, Susanne P.

    2016-01-01

    Elevated carbon dioxide levels and the resultant ocean acidification (OA) are changing the abiotic conditions of the oceans at a greater rate than ever before and placing pressure on marine species. Understanding the response of marine fauna to this change is critical for understanding the effects of OA. Population-level variation in OA tolerance is highly relevant and important in the determination of ecosystem resilience and persistence, but has received little focus to date. In this study, whether OA has the same biological consequences in high-salinity-acclimated population versus a low-salinity-acclimated population of the same species was investigated in the marine isopod Idotea balthica. The populations were found to have physiologically different responses to OA. While survival rate was similar between the two study populations at a future CO2 level of 1000 ppm, and both populations showed increased oxidative stress, the metabolic rate and osmoregulatory activity differed significantly between the two populations. The results of this study demonstrate that the physiological response to OA of populations from different salinities can vary. Population-level variation and the environment provenance of individuals used in OA experiments should be taken into account for the evaluation and prediction of climate change effects. PMID:27053741

  13. Population policy in the United States.

    PubMed

    Corsa, L

    1979-01-01

    The importance of population in the richer nations is seen in terms of increasing demand for fuels and the resultant pollution of air and water. All governments have a population policy, even if it negative and even if it is impied. U.S. federal funding for family planning, lack of funding for abortion, and immigration laws make up part of the U.S. population policy, an inconsistent policy. The 1970-72 Commission of Population Growth and the American Future called for stabilized growth, i.e. zero population growth. This is also the position of the Sierra Club and other organizations. So far, American presidents have not stated their position on the issue. In order to formulate a national population policy, the values must be recognized which a policy would affect. All national agovernments should provide widespread population education activities, provide easily available and safe family planning services, and incorporate demographic data into their planning. Population policy must be comprehensive and longterm. In the case of the U.S., it msut carry over from 1 administration to the next. The U.S. government has lagged behind in formulation of population policy. Private sector groups, e.g., the Sierra Club, must now take the lead.

  14. School Enrollment in the United States: 2006. Population Characteristics. Current Population Reports

    ERIC Educational Resources Information Center

    Davis, Jessica W.; Bauman, Kurt J.

    2008-01-01

    This report discusses school enrollment levels and trends in the population aged 3 and older based on data collected in 2006 by the U.S. Census Bureau in the American Community Survey (ACS) and the Current Population Survey (CPS). Historically, the CPS has been the only data source used to produce school enrollment reports. This is the first…

  15. Modeling Honey Bee Populations.

    PubMed

    Torres, David J; Ricoy, Ulises M; Roybal, Shanae

    2015-01-01

    Eusocial honey bee populations (Apis mellifera) employ an age stratification organization of egg, larvae, pupae, hive bees and foraging bees. Understanding the recent decline in honey bee colonies hinges on understanding the factors that impact each of these different age castes. We first perform an analysis of steady state bee populations given mortality rates within each bee caste and find that the honey bee colony is highly susceptible to hive and pupae mortality rates. Subsequently, we study transient bee population dynamics by building upon the modeling foundation established by Schmickl and Crailsheim and Khoury et al. Our transient model based on differential equations accounts for the effects of pheromones in slowing the maturation of hive bees to foraging bees, the increased mortality of larvae in the absence of sufficient hive bees, and the effects of food scarcity. We also conduct sensitivity studies and show the effects of parameter variations on the colony population.

  16. Population: fiction and fact.

    PubMed

    1979-09-01

    This article was written to refute some common misunderstandings regarding worldwide population levels and worldwide nutrition levels. The world food supply is able to keep pace with high population growth levels. Worl food production currently meets world need; the problem is a distribution system which allocates food only to those who can pay rather than to those who need it. In many developing countries, the best agricultural lands are reserved for commercial crops rather than for subsistence crops. The U.S. food aid program does not help the most needy nations generally. The rate of world population growth is already slowing down. The desire for large families in developing countries is very often a realistic reaction to the prevailing economic system. Family planning programs will succeed. They will succeed even better in countries where general development planning is undertaken concurrently with family planning. Environmental problems are attributable to the consumption explosion in the rich countries rather than to the population explosion in the poor countries.

  17. Modeling Honey Bee Populations

    PubMed Central

    Torres, David J.; Ricoy, Ulises M.; Roybal, Shanae

    2015-01-01

    Eusocial honey bee populations (Apis mellifera) employ an age stratification organization of egg, larvae, pupae, hive bees and foraging bees. Understanding the recent decline in honey bee colonies hinges on understanding the factors that impact each of these different age castes. We first perform an analysis of steady state bee populations given mortality rates within each bee caste and find that the honey bee colony is highly susceptible to hive and pupae mortality rates. Subsequently, we study transient bee population dynamics by building upon the modeling foundation established by Schmickl and Crailsheim and Khoury et al. Our transient model based on differential equations accounts for the effects of pheromones in slowing the maturation of hive bees to foraging bees, the increased mortality of larvae in the absence of sufficient hive bees, and the effects of food scarcity. We also conduct sensitivity studies and show the effects of parameter variations on the colony population. PMID:26148010

  18. Population and women's health.

    PubMed

    Abernethy, V

    1994-01-01

    Explanations of cultural patterns can be found in the economic context (carrying capacity) in which they develop. Population pressure explains the abuse of women throughout history and in modern times because overpopulation leads to devaluation of women's reproductive capacity. A cultural response to overpopulation includes practices that limit the numbers of women of reproductive age. Such practices foster son preference, which results in selective abortion, female infanticide, neglect and overwork of girls, dowry deaths, and discrimination against widows. The results of these practices are manifest in sex ratios that are culturally rather than naturally controlled and in demographic facts such as the calculation that 60 million females are missing in Asia alone (and perhaps more than 100 million worldwide). Women are also removed from a reproductive setting by being kidnapped or sold into prostitution or by being forced to adopt prostitution for economic survival. In cases where survival is threatened by environmental degradation and population growth, the most harsh cultural practices will emerge to adapt the population to the resources at hand. This situation creates an ethical dilemma posed by the problem of imposing Western values on a culture that is undertaking adaptive practices to insure its very survival. Ways to help women in these situation include limiting population growth humanely through family planning, provision of paid work to women, and creation of an environment that supports a small family ideal. Prosperity itself, through modernization, sometimes causes family sizes to increase. The most important intervention appears to be the provision of paid employment outside the home for women. On the other hand, large-scale wealth transfers and liberal immigration policies simply send signals that population pressure is a regional problem that can be alleviated by the international community. Increasing immigration to developed countries will place

  19. We must tackle population problems.

    PubMed

    Hironaka, W

    1992-03-01

    Thank you Mr. Chairman, for the opportunity to speak out not only as a Japanese parliamentarian, but also as a member of GLOBE International, Global Legislators Organization for a Balanced Environment, consisting of legislators from the US Congress, EC Parliament, USSR Assembly and Japanese Diet who have joined together to compare, improve and coordinate our respective legislative activities in an effort to effectively address the complex issues surrounding environment and development. Mr. Chairman, world population--which reached 5.4 billion in mid-1991--is growing exponentially. According to 1 UNFPA report 3 people are born every second, a total of 250,000 people every day or 95-100 million people every year. At this rate, world population will reach 6.4 billion by year 2001, and if this rate continues to go unchecked, world population will reach 14-15 billion by the end of the 21st century. GLOBE is highly aware of the relationship between rapidly growing human populations, environmental degradation and sustainable development. We urge UNCED negotiators to address population growth rates and the integrally linked concerns of resource consumption levels, particularly in the industrialized world, in their search for solutions to the conflict between environment and development. Negotiators should also seriously consider ways in which to broaden educational and economic opportunities for women to ease population growth rates, and to alleviate poverty and stresses on the environment that result from population pressures. Social and economic factors must be integrated into population planning. It is saddening to note that almost 40,000 children die every day due to malnutrition, lack of fresh water and access to resources. Over 100 million children do not receive a primary education. Mr. Chairman, worldwide demand for a range of family planning services is increasing faster than supply. Recent studies indicate that if quality family planning information, training and

  20. [Population and development].

    PubMed

    Trias, M

    1987-01-01

    Human reproduction and development are contrasted; they are intimately linked despite the fact that they may be considered antitheses of each other from many points of view. Presently technological development and the advance of humans into every available corner of living space threaten to place the whole world environment in danger. The Green revolution of the 1960s addressed problems of underproduction of food for the world's population, without providing for the effective distribution of the new surpluses, and without addressing the problem of the ecological impact. 2 trends which are regarded by some with alarm: the migration of populations to the cities and the aging of the population with the connected burden on health care systems, are inevitable, and it is not clear that they are completely negative trends. Addressing these issues will have positive effects in the long run: congestion in the cities, the result of mechanization of rural industry which also results in a greater abundance of agricultural products necessary to society, should force serious consideration of problems such as solid waste management. Coming to terms with the costs of intervention to save lives among the very frail elderly and the prematurely born will have the effect of bringing controversial topics such as euthenasia and eugenics to discussion. The important role played by economic development in the braking of population expansion is underlined.

  1. Population dynamics on heterogeneous bacterial substrates

    NASA Astrophysics Data System (ADS)

    Mobius, Wolfram; Murray, Andrew W.; Nelson, David R.

    2012-02-01

    How species invade new territories and how these range expansions influence the population's genotypes are important questions in the field of population genetics. The majority of work addressing these questions focuses on homogeneous environments. Much less is known about the population dynamics and population genetics when the environmental conditions are heterogeneous in space. To better understand range expansions in two-dimensional heterogeneous environments, we employ a system of bacteria and bacteriophage, the viruses of bacteria. Thereby, the bacteria constitute the environment in which a population of bacteriophages expands. The spread of phage constitutes itself in lysis of bacteria and thus formation of clear regions on bacterial lawns, called plaques. We study the population dynamics and genetics of the expanding page for various patterns of environments.

  2. Population at risk: using areal interpolation and Twitter messages to create population models for burglaries and robberies

    PubMed Central

    2018-01-01

    ABSTRACT Population at risk of crime varies due to the characteristics of a population as well as the crime generator and attractor places where crime is located. This establishes different crime opportunities for different crimes. However, there are very few efforts of modeling structures that derive spatiotemporal population models to allow accurate assessment of population exposure to crime. This study develops population models to depict the spatial distribution of people who have a heightened crime risk for burglaries and robberies. The data used in the study include: Census data as source data for the existing population, Twitter geo-located data, and locations of schools as ancillary data to redistribute the source data more accurately in the space, and finally gridded population and crime data to evaluate the derived population models. To create the models, a density-weighted areal interpolation technique was used that disaggregates the source data in smaller spatial units considering the spatial distribution of the ancillary data. The models were evaluated with validation data that assess the interpolation error and spatial statistics that examine their relationship with the crime types. Our approach derived population models of a finer resolution that can assist in more precise spatial crime analyses and also provide accurate information about crime rates to the public. PMID:29887766

  3. Applying Thiessen Polygon Catchment Areas and Gridded Population Weights to Estimate Conflict-Driven Population Changes in South Sudan

    NASA Astrophysics Data System (ADS)

    Jordan, L.

    2017-10-01

    Recent violence in South Sudan produced significant levels of conflict-driven migration undermining the accuracy and utility of both national and local level population forecasts commonly used in demographic estimates, public health metrics and food security proxies. This article explores the use of Thiessen Polygons and population grids (Gridded Population of the World, WorldPop and LandScan) as weights for estimating the catchment areas for settlement locations that serve large populations of internally displaced persons (IDP), in order to estimate the county-level in- and out-migration attributable to conflict-driven displacement between 2014-2015. Acknowledging IDP totals improves internal population estimates presented by global population databases. Unlike other forecasts, which produce spatially uniform increases in population, accounting for displaced population reveals that 15 percent of counties (n = 12) increased in population over 20 percent, and 30 percent of counties (n = 24) experienced zero or declining population growth, due to internal displacement and refugee out-migration. Adopting Thiessen Polygon catchment zones for internal migration estimation can be applied to other areas with United Nations IDP settlement data, such as Yemen, Somalia, and Nigeria.

  4. Population and Australian development assistance.

    PubMed

    Jones, R

    1992-07-01

    Australia's position on international population issues is consistent with the major international statements on population: the World Population Plan of Action (1974), the Mexico City Declaration (1984), and the Amsterdam Declaration (1989). Australia's policy emphasizes the importance of population policies as an integral part of social, economic, and cultural development aimed at improving the quality of life of the people. Factors that would promote smaller families include improving economic opportunities, old-age security, education and health (particularly for women), as well as improving the accessibility and quality of family planning services. The quality of care approach is directly complementary to the Australian International Development Assistance Bureau (AIDAB)'s Women-In-Development Policy and its Health Policy, which stresses the theme of Women And Their Children's Health (WATCH). Australia's support for population programs and activities has increased considerably over the last few years. Total assistance for the year 1990/91 was around $7 million out of a total aid program of $1216 million. In recent years AIDAB has funded family planning activities or health projects with family planning components in a number of countries in the Asia-Pacific region. In the South Pacific region AIDAB has funded a reproductive health video project taking into consideration the cultural sensitivities and customs of the peoples of the region. AIDAB has supported a UN Population Fund project in Thailand that aims to strengthen the capacity of the National Statistical Office to collect population data. The US currently accounts for around 40% of all population-related development assistance to improve the health of women and children through family planning. The other major donors are Japan, the Scandinavian countries, and the Netherlands. Funding for population has been a relatively low percentage of overall development assistance budgets in OECD countries. In the

  5. Causes, trends, and policy of population migration and the floating population.

    PubMed

    Cai, F

    1996-01-01

    This study provides a discussion of migration theory, a description of the main characteristics of migrants and floating population in China, and a migration impact assessment and potential social policy directions. It is argued that the impetus for migration in China was the population distribution pattern and an uneven industrial structure that favored heavy industry. Another factor affecting migration is the gap in income between urban and rural areas, which has widened since reforms in the mid-1980s. The author finds the Todaro or the Harris-Todaro theories inappropriate for understanding migration in developing countries and flawed. Evidence about migrants' characteristics suggest that migration in China was part of a process governed by the laws of economic growth and market development. Legal migrants are defined as those who legally migrated according to the household registration system. China's development strategy during the 1950s relied on growth of capital-intensive heavy industry. The cost was underwritten by adoption of a price system that shifted the price of products in order to lower the cost of heavy industrial development. During 1952-78, agricultural output dropped sharply, but the employment structure changed very little and the rate of urbanization changed slightly. Regional inequality was obvious by 1978. As reform progressed, patterns emerged that favored eastern coastal development. Microlevel reform outdistanced macrolevel reform. Obstacles to migration were reduced: the breakup of the commune system and changes in the urban food supply system and housing. In 1990 there were 34.128 million migrants, of which 32.42% were interprovincial and 42.99% involved job-related shifts. In 1992, 8.1% of urban population were not registered; 94.909 million were floating population. Cities have established policies to match the size of the floating population to the current carrying capacity.

  6. Transcript analysis in two alfalfa salt tolerance selected breeding populations relative to a non-tolerant population.

    PubMed

    Gruber, M Y; Xia, J; Yu, M; Steppuhn, H; Wall, K; Messer, D; Sharpe, A G; Acharya, S N; Wishart, D S; Johnson, D; Miller, D R; Taheri, A

    2017-02-01

    With the growing limitations on arable land, alfalfa (a widely cultivated, low-input forage) is now being selected to extend cultivation into saline lands for low-cost biofeedstock purposes. Here, minerals and transcriptome profiles were compared between two new salinity-tolerant North American alfalfa breeding populations and a more salinity-sensitive western Canadian alfalfa population grown under hydroponic saline conditions. All three populations accumulated two-fold higher sodium in roots than shoots as a function of increased electrical conductivity. At least 50% of differentially expressed genes (p < 0.05) were down-regulated in the salt-sensitive population growing under high salinity, while expression remained unchanged in the saline-tolerant populations. In particular, most reduction in transcript levels in the salt-sensitive population was observed in genes specifying cell wall structural components, lipids, secondary metabolism, auxin and ethylene hormones, development, transport, signalling, heat shock, proteolysis, pathogenesis-response, abiotic stress, RNA processing, and protein metabolism. Transcript diversity for transcription factors, protein modification, and protein degradation genes was also more strongly affected in salt-tolerant CW064027 than in salt-tolerant Bridgeview and salt-sensitive Rangelander, while both saline-tolerant populations showed more substantial up-regulation in redox-related genes and B-ZIP transcripts. The report highlights the first use of bulked genotypes as replicated samples to compare the transcriptomes of obligate out-cross breeding populations in alfalfa.

  7. The Population Activist's Handbook.

    ERIC Educational Resources Information Center

    Population Inst., Washington, DC.

    This handbook is a guide to effective action strategies on dealing with overpopulation. Divided into five sections, the book outlines programs, suggests references, and lists resources that are helpful for thinking and for planning action on population issues. Section one focuses on strategies to change the current population policy choices made…

  8. Marketing and population problems.

    PubMed

    Farley, J U; Leavitt, H J

    1971-07-01

    There are many elements in population programs that are more familiar to marketing men than to some population experts. Advertising is essential to reach the target population, and advertising evaluation techniques (e.g., surrogate indexes or audience measures) might be useful for evaluating both population information activities and the import of the entire program. Fundamental research on basid demand for fertility control is needed and a marketer's experience with planning and evaluating test markets can be useful in assessing potential selling targets and evaluating alternative promotional and distributional strategies. Special family planning clinics have certain disadvantages: expensive and scarce personnel are needed; red tape may be present; the network is based on the assumption that the client is willing to travel relatively great distances repeatedly; and clinics lack anonymity which may scare potential acceptors away. Most developing cultures have an intensively functioning distribution structure which delivers basic commodities to the most remote areas, providing relatively anonymous outlets that are physically close to the customs. Materials requiring a prescription might be distributed in exchange for script issued at and ultimately redeemed by clinics, this requiring only an occasional visit to a clinic. Mail-order service can be used to supplement a clinic's distribution of some contraceptives. It should be remembered that population administrators often have an antipathetic view toward business and marketing and "suspect" the profit motive.

  9. Bucharest: poverty or population?

    PubMed

    1974-01-01

    The controversy that occurred in Bucharest over the World Population Plan of Action had not been totally anticipated. Prior to the Conference, there appeared to be a general consensus that population growth was the crucial issue although it was recognized that population growth had to be considered in the context of socioeconomic and cultural development. What developed at Bucharest was a clear division between the developed countries who favored population control and implementation of family planning programs by 1986 and the developing countries who rejected the idea of population control unless it was associated with the redistribution of world resources. The reality of people having large families because they are poor cannot be denied, but, simultaneously, the problem of increasing numbers and their impact on the quality of life, nutrition, housing, education, and employment must be faced. Since affluent countries cannot be relied upon concerning the redistribution of their wealth, developing countries can bring about some change by redistributing the wealth within their countries. Adult literacy programs have been identified as a means to promote socioeconomic development, but these programs will only prove successful if they involve the adults in the process of learning by means of problem solving and cause them to reflect on their socioeconomic situation with the result of reinvolving themselves in society in order to change it.

  10. Population trends in Malaysia: 1970-2010

    NASA Astrophysics Data System (ADS)

    Rashid, Saharani Abdul; Ghani, Puzziawati Ab; Daud, Noorizam

    2014-12-01

    The size of population in Malaysia had reached 28.3 million in 2010 and is expected to increase to 38.6 million in the next 30 years. This demographic milestone that is causing renewed attention to the challenges caused by population growth. This paper looks at the last 40 years of changes in Malaysia population structure due to the changes in demographic phenomenon using data obtained from the Department of Statistics Malaysia. The principal finding of this research indicates that population structure in Malaysia had changed dramatically from the year 1970 to 2010. At the same time, Malaysia has completed its demographic transition in less than four decades. The fall in fertility and mortality rates have led to an improvement in the life expectancy of the population which has resulted an ageing population in Malaysia.

  11. Retrospect and prospect of China's population.

    PubMed

    Liu, G

    1985-03-01

    This discussion of the population of China covers the reproductive pattern and fertility rate, the death pattern and mortality, age-sex structure of the population, population and employment, urbanization, migration, and the aging of the population. During the 1949-83 period, China almost doubled her population with an annual natural growth rate of 19/1000. China's reproductive pattern developed from early childbearing, short birth spacing and many births to later childbearing, longer birth spacing and fewer births. China's total fertility rate (TFR) was 5.8 in 1950 and 2.1 in 1983 with an annual decrease of 3%. The annual national income grew at a rate of 7.1%, while the annual growth rate of population 1.9% from 1950-82. Consequently, the national income per capita increased from 50 yuan in 1950 to 338 yuan in 1982. The major factor responsible for the changes is the remarkable decline in the rural fertility rate. The crude death rate dropped from 27.1/1000 in 1963 to 7.1 in 1983 and the infant mortality rate from 179.4/1000 live births in 1936 to 36.6 in 1981. There was also a significant change in the causes of death. Population aged 0-14 in China account for 33.6%, 15-49 for 51.3%, and 50 and over for 15.1% of the total population. China is in the process of transition from an expansive to a stationary population. The age-dependency ratio declined from 68.6% in 1953 and 79.4% in 1964 to 62.6% in 1982. Sex ratios recorded in the 3 population censuses are 105.99 in 1953, 105.45 in 1964, and 105.46 in 1982. Employment in both collective and individual economies did not expand until 1978. Sectoral, occupational, and industrial structures of population started to change rationally with the adjustment and reform of economic management system in 1978. The strategic stress on the employment of China's economically active population should be shifted from farming to diversified economy and urban industry and commerce, from sectors of industrial-agricultural production

  12. Group selections among laboratory populations of Tribolium.

    PubMed

    Wade, M J

    1976-12-01

    Selection at the population level or group selection is defined as genetic change that is brought about or maintained by the differential extinction and/or proliferation of populations. Group selection for both increased and decreased adult population size was carried out among laboratory populations of Tribolium castaneum at 37-day intervals. The effect of individual selection within populations on adult population size was evaluated in an additional control series of populations. The response in the group selection treatments occurred rapidly, within three or four generations, and was large in magnitude, at times differing from the controls by over 200%. This response to selection at the populational level occurred despite strong individual selection which caused a decline in the mean size of the control populations from over 200 adults to near 50 adults in nine 37-day intervals. "Assay" experiments indicated that selective changes in fecundity, developmental time, body weight, and cannibalism rates were responsible in part for the observed treatment differences in adult population size. These findings have implications in terms of speciation in organisms whose range is composed of many partially isolated local populations.

  13. Population pressures: threat to democracy.

    PubMed

    1992-06-01

    The desire for political freedom and representative government is spreading throughout the world. The stability of democratic bodies is dependent on wise leaders, foreign aid, and slowing population growth. Rapid population growth strains political institutions and increases pressure on services. A Population Crisis Committee study found that only a few democratic countries with serious demographic pressures remained stable. The most stable countries were ones with lower levels of population pressure. Most of the 31 unstable countries were in Africa and in a band stretching from the Middle East to South Asia, and almost all had serious demographic pressures. Only 5 stable countries had high or very high demographic pressures. Since countries in the world are interdependent, population pressures have adverse consequences everywhere. Population pressures in the developing world are considered enhanced by the rapid growth of cities. Both the developed and the developing world face the problems of clogged highways, loss of wilderness, polluted lakes and streams, and stifling smog and acid rain conditions. The sociopolitical implications of demographic changes vary from country to country, but rapid growth and maldistribution of population strains existing political, social, and economic structures and relations between nations. Urban areas are the arena for clashes of cultures, competition for scarce housing and jobs, the breakdown of traditional family and social structures, and juxtapositions of extreme wealth next to extreme poverty. The growth of independent nation states since the 1940s has not allowed much time for development of effective political institutions. There are many obstacles to national unity and popular political participation. The potential for political instability is correlated with a number of factors: large youth populations in overcrowded cities with too high expectations and limited opportunities, diverse and intense ethnic and religious

  14. Canada's population: growth and dualism.

    PubMed

    Beaujot, R P

    1978-04-01

    In Canada the current 1.3% population growth rate is causing some concern. Those concerned argue that such a rate of growth in combination with high levels of consumption could jeopardize the country's resource base and its comfortable style of living. Many Canadians are questioning high levels of immigration, for now that the fertility level is below replacement level, net immigration contributes substantially to population growth (over 1/3 in 1976). The growing proportion of non-Europeans among recent immigrants is causing resentment, and, in a tight job market, immigrants are regarded as threats to the World War 2 baby boom cohort who are now at working ages. The baby boom generation also puts stress on housing and health services, and it will increase the need for pension checks as it ages. Although French fertility is no longer high and immigration is no longer dominated by the British, the French group's 200-year struggle to preserve its identity continues on in the current effort of the Quebec government to enforce the use of French language by law within that province. Geography and climate dictate another demographic fact that divides the country and pervades its history. In addition to intense regionalism, uneven population distribution is responsible for 2 other concerns: the rapid growth of several already large cities and depopulation of many small communities. Focus in this discussion is on Canada's population growth in the past and as projected for the future, historical and current fertility, mortality and immigration trends, the search for a new immigration policy, the impact of the baby boom generation on the population's age structure and the problems this creates, and recent shifts in population distribution and in the country's ethnic and linguistic makeup. The population policy proposals evolved thus far involve to a great extent the use of immigration as a lever for achieving given population objectives.

  15. Why Population Matters, 1996.

    ERIC Educational Resources Information Center

    Population Action International, Washington, DC.

    Population growth around the world affects Americans through its impact on economy, environment, safety, and health, and the condition of the world children will inherit. The cumulative evidence is strong that current rates of population growth pose significant and interacting risks to human well-being and are a legitimate concern for Americans.…

  16. Population structure of Vibrio fischeri within the light organs of Euprymna scolopes squid from Two Oahu (Hawaii) populations.

    PubMed

    Wollenberg, M S; Ruby, E G

    2009-01-01

    We resolved the intraspecific diversity of Vibrio fischeri, the bioluminescent symbiont of the Hawaiian sepiolid squid Euprymna scolopes, at two previously unexplored morphological and geographical scales. These scales ranged from submillimeter regions within the host light organ to the several kilometers encompassing two host populations around Oahu. To facilitate this effort, we employed both novel and standard genetic and phenotypic assays of light-organ symbiont populations. A V. fischeri-specific fingerprinting method and five phenotypic assays were used to gauge the genetic richness of V. fischeri populations; these methods confirmed that the symbiont population present in each adult host's light organ is polyclonal. Upon statistical analysis of these genetic and phenotypic population data, we concluded that the characteristics of symbiotic populations were more similar within individual host populations than between the two distinct Oahu populations of E. scolopes, providing evidence that local geographic symbiont population structure exists. Finally, to better understand the genesis of symbiont diversity within host light organs, the process of symbiosis initiation in newly hatched juvenile squid was examined both experimentally and by mathematical modeling. We concluded that, after the juvenile hatches, only one or two cells of V. fischeri enter each of six internal epithelium-lined crypts present in the developing light organ. We hypothesize that the expansion of different, crypt-segregated, clonal populations creates the polyclonal adult light-organ population structure observed in this study. The stability of the luminous-bacterium-sepiolid squid mutualism in the presence of a polyclonal symbiont population structure is discussed in the context of contemporary evolutionary theory.

  17. Inner and inter population structure construction of Chinese Jiangsu Han population based on Y23 STR system

    PubMed Central

    Yang, Chun; Zhang, Jianqiu

    2017-01-01

    In this study, we analyzed the genetic polymorphisms of 23 Y-STR loci from PowerPlex® Y23 system in 916 unrelated healthy male individuals from Chinese Jiangsu Han, and observed 912 different haplotypes including 908 unique haplotypes and 4 duplicate haplotypes. The haplotype diversity reached 0.99999 and the discrimination capacity and match probability were 0.9956 and 0.0011, respectively. The gene diversity values ranged from 0.3942 at DYS438 to 0.9607 at DYS385a/b. Population differentiation within 10 Jiangsu Han subpopulations were evaluated by RST values and visualized in Neighbor-Joining trees and Multi-Dimensional Scaling plots as well as population relationships between the Jiangsu Han population and other 18 Eastern Asian populations. Such results indicated that the 23 Y-STR loci were highly polymorphic in Jiangsu Han population and played crucial roles in forensic application as well as population genetics. For the first time, we reported the genetic diversity of male lineages in Jiangsu Han population at a high-resolution level of 23 Y-STR set and consequently contributed to familial searching, offender tracking, and anthropology analysis of Jiangsu Han population. PMID:28704439

  18. Genetic Diversity and Population Structure of Ethiopian Sheep Populations Revealed by High-Density SNP Markers

    PubMed Central

    Edea, Zewdu; Dessie, Tadelle; Dadi, Hailu; Do, Kyoung-Tag; Kim, Kwan-Suk

    2017-01-01

    Sheep in Ethiopia are adapted to a wide range of environments, including extreme habitats. Elucidating their genetic diversity is critical for improving breeding strategies and mapping quantitative trait loci associated with productivity. To this end, the present study investigated the genetic diversity and population structure of five Ethiopian sheep populations exhibiting distinct phenotypes and sampled from distinct production environments, including arid lowlands and highlands. To investigate the genetic relationships in greater detail and infer population structure of Ethiopian sheep breeds at the continental and global levels, we analyzed genotypic data of selected sheep breeds from the Ovine SNP50K HapMap dataset. All Ethiopian sheep samples were genotyped with Ovine Infinium HD SNP BeadChip (600K). Mean genetic diversity ranged from 0.29 in Arsi-Bale to 0.32 in Menz sheep, while estimates of genetic differentiation among populations ranged from 0.02 to 0.07, indicating low to moderate differentiation. An analysis of molecular variance revealed that 94.62 and 5.38% of the genetic variation was attributable to differences within and among populations, respectively. Our population structure analysis revealed clustering of five Ethiopian sheep populations according to tail phenotype and geographic origin—i.e., short fat-tailed (very cool high-altitude), long fat-tailed (mid to high-altitude), and fat-rumped (arid low-altitude), with clear evidence of admixture between long fat-tailed populations. North African sheep breeds showed higher levels of within-breed diversity, but were less differentiated than breeds from Eastern and Southern Africa. When African breeds were grouped according to geographic origin (North, South, and East), statistically significant differences were detected among groups (regions). A comparison of population structure between Ethiopian and global sheep breeds showed that fat-tailed breeds from Eastern and Southern Africa clustered

  19. Long-term population cycles in human societies.

    PubMed

    Turchin, Peter

    2009-04-01

    Human population dynamics are usually conceptualized as either boundless growth or growth to an equilibrium. The implicit assumption underlying these paradigms is that any feedback processes regulating population density, if they exist, operate on a fast-time-scale, and therefore we do not expect to observe population oscillations in human population numbers. This review asks, are population processes in historical and prehistorical human populations characterized by second-order feedback loops, that is, regulation involving lags? If yes, then the implications for forecasting future population change are obvious--what may appear as inexplicable, exogenously driven reverses in population trends may actually be a result of feedbacks operating with substantial time lags. This survey of a variety of historical and archeological data indicates that slow oscillations in population numbers, with periods of roughly two to three centuries, are observed in a number of world regions and historical periods. Next, a potential explanation for this pattern, the demographic-structural theory, is discussed. Finally, the implications of these results for global population forecasts is discussed.

  20. Declines in low-elevation subalpine tree populations outpace growth in high-elevation populations with warming

    DOE PAGES

    Conlisk, Erin; Castanha, Cristina; Germino, Matthew J.; ...

    2017-02-08

    Species distribution shifts in response to climate change require that recruitment increase beyond current range boundaries. For trees with long life spans, the importance of climate-sensitive seedling establishment to the pace of range shifts has not been demonstrated quantitatively. Using spatially explicit, stochastic population models combined with data from long-term forest surveys, we explored whether the climate-sensitivity of recruitment observed in climate manipulation experiments was sufficient to alter populations and elevation ranges of two widely distributed, high-elevation North American conifers. Empirically observed, warming-driven declines in recruitment led to rapid modelled population declines at the low-elevation, ‘warm edge’ of subalpine forestmore » and slow emergence of populations beyond the high-elevation, ‘cool edge’. Because population declines in the forest occurred much faster than population emergence in the alpine, we observed range contraction for both species. For Engelmann spruce, this contraction was permanent over the modelled time horizon, even in the presence of increased moisture. For limber pine, lower sensitivity to warming may facilitate persistence at low elevations – especially in the presence of increased moisture – and rapid establishment above tree line, and, ultimately, expansion into the alpine. Synthesis. Assuming 21st century warming and no additional moisture, population dynamics in high-elevation forests led to transient range contractions for limber pine and potentially permanent range contractions for Engelmann spruce. Thus, limitations to seedling recruitment with warming can constrain the pace of subalpine tree range shifts.« less

  1. Declines in low-elevation subalpine tree populations outpace growth in high-elevation populations with warming

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

    Conlisk, Erin; Castanha, Cristina; Germino, Matthew J.

    Species distribution shifts in response to climate change require that recruitment increase beyond current range boundaries. For trees with long life spans, the importance of climate-sensitive seedling establishment to the pace of range shifts has not been demonstrated quantitatively. Using spatially explicit, stochastic population models combined with data from long-term forest surveys, we explored whether the climate-sensitivity of recruitment observed in climate manipulation experiments was sufficient to alter populations and elevation ranges of two widely distributed, high-elevation North American conifers. Empirically observed, warming-driven declines in recruitment led to rapid modelled population declines at the low-elevation, ‘warm edge’ of subalpine forestmore » and slow emergence of populations beyond the high-elevation, ‘cool edge’. Because population declines in the forest occurred much faster than population emergence in the alpine, we observed range contraction for both species. For Engelmann spruce, this contraction was permanent over the modelled time horizon, even in the presence of increased moisture. For limber pine, lower sensitivity to warming may facilitate persistence at low elevations – especially in the presence of increased moisture – and rapid establishment above tree line, and, ultimately, expansion into the alpine. Synthesis. Assuming 21st century warming and no additional moisture, population dynamics in high-elevation forests led to transient range contractions for limber pine and potentially permanent range contractions for Engelmann spruce. Thus, limitations to seedling recruitment with warming can constrain the pace of subalpine tree range shifts.« less

  2. Declines in low-elevation subalpine tree populations outpace growth in high-elevation populations with warming

    USGS Publications Warehouse

    Conlisk, Erin; Castanha, Cristina; Germino, Matthew J.; Veblen, Thomas T; Smith, Jeremy M.; Kueppers, Lara M.

    2017-01-01

    Species distribution shifts in response to climate change require that recruitment increase beyond current range boundaries. For trees with long life spans, the importance of climate-sensitive seedling establishment to the pace of range shifts has not been demonstrated quantitatively.Using spatially explicit, stochastic population models combined with data from long-term forest surveys, we explored whether the climate-sensitivity of recruitment observed in climate manipulation experiments was sufficient to alter populations and elevation ranges of two widely distributed, high-elevation North American conifers.Empirically observed, warming-driven declines in recruitment led to rapid modelled population declines at the low-elevation, ‘warm edge’ of subalpine forest and slow emergence of populations beyond the high-elevation, ‘cool edge’. Because population declines in the forest occurred much faster than population emergence in the alpine, we observed range contraction for both species. For Engelmann spruce, this contraction was permanent over the modelled time horizon, even in the presence of increased moisture. For limber pine, lower sensitivity to warming may facilitate persistence at low elevations – especially in the presence of increased moisture – and rapid establishment above tree line, and, ultimately, expansion into the alpine.Synthesis. Assuming 21st century warming and no additional moisture, population dynamics in high-elevation forests led to transient range contractions for limber pine and potentially permanent range contractions for Engelmann spruce. Thus, limitations to seedling recruitment with warming can constrain the pace of subalpine tree range shifts.

  3. Classification of stellar populations in globular clusters

    NASA Astrophysics Data System (ADS)

    Wang, Yue; Zhao, Gang; Li, Hai-Ning

    2017-04-01

    Possessing multiple stellar populations has been accepted as a common feature of globular clusters (GCs). Different stellar populations manifest themselves with different chemical features, e.g. the well-known O-Na anti-correlation. Generally, the first (primordial) population has O and Na abundances consistent with those of field stars with similar metallicity; while the second (polluted) population is identified by their Na overabundance and O deficiency. The fraction of the populations is an important constraint on the GC formation scenario. Several methods have been proposed for the classification of GC populations. Here we examine a criterion derived based on the distribution of Galactic field stars, which relies on Na abundance as a function of [Fe/H], to distinguish first and second stellar populations in GCs. By comparing the first population fractions of 17 GCs estimated by the field star criterion with those in the literature derived by methods related to individual GCs, we find that the field star criterion tends to overestimate the first population fractions. The population separation methods, which are related to an individual GC sample, are recommended because the diversity of GCs can be taken into consideration. Currently, more caution should be exercised if one wants to regard field stars as a reference for the identification of a GC population. However, further study on the connection between field stars and GCs populations is still needed.

  4. Establishment probability in newly founded populations.

    PubMed

    Gusset, Markus; Müller, Michael S; Grimm, Volker

    2012-06-20

    Establishment success in newly founded populations relies on reaching the established phase, which is defined by characteristic fluctuations of the population's state variables. Stochastic population models can be used to quantify the establishment probability of newly founded populations; however, so far no simple but robust method for doing so existed. To determine a critical initial number of individuals that need to be released to reach the established phase, we used a novel application of the "Wissel plot", where -ln(1 - P0(t)) is plotted against time t. This plot is based on the equation P(0)t=1-c(1)e(-ω(1t)), which relates the probability of extinction by time t, P(0)(t), to two constants: c(1) describes the probability of a newly founded population to reach the established phase, whereas ω(1) describes the population's probability of extinction per short time interval once established. For illustration, we applied the method to a previously developed stochastic population model of the endangered African wild dog (Lycaon pictus). A newly founded population reaches the established phase if the intercept of the (extrapolated) linear parts of the "Wissel plot" with the y-axis, which is -ln(c(1)), is negative. For wild dogs in our model, this is the case if a critical initial number of four packs, consisting of eight individuals each, are released. The method we present to quantify the establishment probability of newly founded populations is generic and inferences thus are transferable to other systems across the field of conservation biology. In contrast to other methods, our approach disaggregates the components of a population's viability by distinguishing establishment from persistence.

  5. World Population in Transition.

    ERIC Educational Resources Information Center

    Merrick, Thomas W.; And Others

    1986-01-01

    This issue discusses world population trends and their implications for more and less developed countries. There have been two periods of major population expansion since 1750 with the first lasting almost 200 years and the second surge occurring after World War II. Growth rates in industrialized countries are now very low with fertility below…

  6. Competition in size-structured populations: mechanisms inducing cohort formation and population cycles.

    PubMed

    de Roos, André M; Persson, Lennart

    2003-02-01

    In this paper we investigate the consequences of size-dependent competition among the individuals of a consumer population by analyzing the dynamic properties of a physiologically structured population model. Only 2 size-classes of individuals are distinguished: juveniles and adults. Juveniles and adults both feed on one and the same resource and hence interact by means of exploitative competition. Juvenile individuals allocate all assimilated energy into development and mature on reaching a fixed developmental threshold. The combination of this fixed threshold and the resource-dependent developmental rate, implies that the juvenile delay between birth and the onset of reproduction may vary in time. Adult individuals allocate all assimilated energy to reproduction. Mortality of both juveniles and adults is assumed to be inversely proportional to the amount of energy assimilated. In this setting we study how the dynamics of the population are influenced by the relative foraging capabilities of juveniles and adults. In line with results that we previously obtained in size-structured consumer-resource models with pulsed reproduction, population cycles primarily occur when either juveniles or adults have a distinct competitive advantage. When adults have a larger per capita feeding rate and are hence competitively superior to juveniles, population oscillations occur that are primarily induced by the fact that the duration of the juvenile period changes with changing food conditions. These cycles do not occur when the juvenile delay is a fixed parameter. When juveniles are competitively superior, two different types of population fluctuations can occur: (1) rapid, low-amplitude fluctuations having a period of half the juvenile delay and (2) slow, large-amplitude fluctuations characterized by a period, which is roughly equal to the juvenile delay. The analysis of simplified versions of the structured model indicates that these two types of oscillations also occur if

  7. Admixture, Population Structure, and F-Statistics.

    PubMed

    Peter, Benjamin M

    2016-04-01

    Many questions about human genetic history can be addressed by examining the patterns of shared genetic variation between sets of populations. A useful methodological framework for this purpose isF-statistics that measure shared genetic drift between sets of two, three, and four populations and can be used to test simple and complex hypotheses about admixture between populations. This article provides context from phylogenetic and population genetic theory. I review how F-statistics can be interpreted as branch lengths or paths and derive new interpretations, using coalescent theory. I further show that the admixture tests can be interpreted as testing general properties of phylogenies, allowing extension of some ideas applications to arbitrary phylogenetic trees. The new results are used to investigate the behavior of the statistics under different models of population structure and show how population substructure complicates inference. The results lead to simplified estimators in many cases, and I recommend to replace F3 with the average number of pairwise differences for estimating population divergence. Copyright © 2016 by the Genetics Society of America.

  8. Towards population-level conservation in the critically endangered Antarctic blue whale: the number and distribution of their populations

    NASA Astrophysics Data System (ADS)

    Attard, Catherine R. M.; Beheregaray, Luciano B.; Möller, Luciana M.

    2016-03-01

    Population-level conservation is required to prevent biodiversity loss within a species, but it first necessitates determining the number and distribution of populations. Many whale populations are still depleted due to 20th century whaling. Whales are one of the most logistically difficult and expensive animals to study because of their mobility, pelagic lifestyle and often remote habitat. We tackle the question of population structure in the Antarctic blue whale (Balaenoptera musculus intermedia) - a critically endangered subspecies and the largest extant animal - by capitalizing on the largest genetic dataset to date for Antarctic blue whales. We found evidence of three populations that are sympatric in the Antarctic feeding grounds and likely occupy separate breeding grounds. Our study adds to knowledge of population structure in the Antarctic blue whale. Future research should invest in locating the breeding grounds and migratory routes of Antarctic blue whales through satellite telemetry to confirm their population structure and allow population-level conservation.

  9. Towards population-level conservation in the critically endangered Antarctic blue whale: the number and distribution of their populations

    PubMed Central

    Attard, Catherine R. M.; Beheregaray, Luciano B.; Möller, Luciana M.

    2016-01-01

    Population-level conservation is required to prevent biodiversity loss within a species, but it first necessitates determining the number and distribution of populations. Many whale populations are still depleted due to 20th century whaling. Whales are one of the most logistically difficult and expensive animals to study because of their mobility, pelagic lifestyle and often remote habitat. We tackle the question of population structure in the Antarctic blue whale (Balaenoptera musculus intermedia) – a critically endangered subspecies and the largest extant animal – by capitalizing on the largest genetic dataset to date for Antarctic blue whales. We found evidence of three populations that are sympatric in the Antarctic feeding grounds and likely occupy separate breeding grounds. Our study adds to knowledge of population structure in the Antarctic blue whale. Future research should invest in locating the breeding grounds and migratory routes of Antarctic blue whales through satellite telemetry to confirm their population structure and allow population-level conservation. PMID:26951747

  10. Probabilistic population projections with migration uncertainty

    PubMed Central

    Azose, Jonathan J.; Ševčíková, Hana; Raftery, Adrian E.

    2016-01-01

    We produce probabilistic projections of population for all countries based on probabilistic projections of fertility, mortality, and migration. We compare our projections to those from the United Nations’ Probabilistic Population Projections, which uses similar methods for fertility and mortality but deterministic migration projections. We find that uncertainty in migration projection is a substantial contributor to uncertainty in population projections for many countries. Prediction intervals for the populations of Northern America and Europe are over 70% wider, whereas prediction intervals for the populations of Africa, Asia, and the world as a whole are nearly unchanged. Out-of-sample validation shows that the model is reasonably well calibrated. PMID:27217571

  11. Population dynamics and habitat sharing of natural populations of Caenorhabditis elegans and C. briggsae

    PubMed Central

    2012-01-01

    Background The nematode Caenorhabditis elegans is a major model organism in laboratory biology. Very little is known, however, about its ecology, including where it proliferates. In the past, C. elegans was mainly isolated from human-made compost heaps, where it was overwhelmingly found in the non-feeding dauer diapause stage. Results C. elegans and C. briggsae were found in large, proliferating populations in rotting plant material (fruits and stems) in several locations in mainland France. Both species were found to co-occur in samples isolated from a given plant species. Population counts spanned a range from one to more than 10,000 Caenorhabditis individuals on a single fruit or stem. Some populations with an intermediate census size (10 to 1,000) contained no dauer larvae at all, whereas larger populations always included some larvae in the pre-dauer or dauer stages. We report on associated micro-organisms, including pathogens. We systematically sampled a spatio-temporally structured set of rotting apples in an apple orchard in Orsay over four years. C. elegans and C. briggsae were abundantly found every year, but their temporal distributions did not coincide. C. briggsae was found alone in summer, whereas both species co-occurred in early fall and C. elegans was found alone in late fall. Competition experiments in the laboratory at different temperatures show that C. briggsae out-competes C. elegans at high temperatures, whereas C. elegans out-competes C. briggsae at lower temperatures. Conclusions C. elegans and C. briggsae proliferate in the same rotting vegetal substrates. In contrast to previous surveys of populations in compost heaps, we found fully proliferating populations with no dauer larvae. The temporal sharing of the habitat by the two species coincides with their temperature preference in the laboratory, with C. briggsae populations growing faster than C. elegans at higher temperatures, and vice at lower temperatures. PMID:22731941

  12. Effective population size and genetic structure of a Piute ground squirrel (Spermophilus mollis) population

    USGS Publications Warehouse

    Antolin, Michael F.; Van Horne, Beatrice; Berger, Michael D.

    2001-01-01

    Piute ground squirrels (Spermophilus mollis) are distributed continuously in habitat dominated by native shrubs and perennial grasses in the Snake River Birds of Prey National Conservation Area in Idaho, U.S.A. This habitat is being fragmented and replaced by exotic annual plants, changing it to a wildfire-dominated system that provides poor habitat for ground squirrels. To assess potential effects of this fragmentation on ground squirrel populations, we combined an estimate of effective population size (Ne) based upon a demographic study with a population genetic analysis. The study area included three subpopulations separated from each other by 8–13 km. The ratio of effective population size to census number (Ne/N) was 0.57. Combining Ne/N with dispersal distances from a radio-tracking study, we calculated that neighborhood size was 62.2 ha, which included between 204 and 480 individuals. Our population genetic analysis (based on randomly amplified polymorphic DNA (RAPD) and microsatellite markers) showed relatively low levels of genetic differentiation (Qpopulations 0.07–0.10) between subpopulations and no inbreeding within subpopulations (f = 0.0003). These estimates of population subdivision translate into an effective migration rate (Nem) of 2.3–3.3 per year, which represents a high level of gene flow. Invasion by exotics will reduce the overall productivity of the habitat, and will lead to isolation among subpopulations if favorable habitat patches become isolated.

  13. Stochastic analysis of future vehicle populations

    DOT National Transportation Integrated Search

    1979-05-01

    The purpose of this study was to build a stochastic model of future vehicle populations. Such a model can be used to investigate the uncertainties inherent in Future Vehicle Populations. The model, which is called the Future Automobile Population Sto...

  14. Keynes, population, and equity prices.

    PubMed

    Tarascio, V J

    1985-01-01

    Keynes in 1937 examined the phenomenon of the Great Depression from a longrun perspective in contradiction to the "General Theory," where the focus was on the shortrun. "Some Economic Consequences of a Declining Population," Keynes' article, reveals the context in which the "General Theory" was written. In the "General Theory," the focus is on short-term fluctuations, i.e., business cycles, but Keynes fails to provide any theoretical explanation as to why the depression of the 1930s was so severe and intractable. In the 1937 article, the depression is seen as the result of the combined effects of a decline in longrun growth due to population growth decline and a shortrun cyclical decline, together producing severe economic consequences. What is important for the purposes of this discussion is the implication, within the context of the 1937 article, that not only was the stock market crash of 1929 related to population change (with its accompanying collapse in expectations) but that, in general, changes in the rate of growth of population are accompanied by stock price movements in the same direction. The remainder of the discussion is devoted to a simple empirical test of this relationship. The data used are population size (POP), defined as the total residential population in the US from 1870-1979, and the Standard and Poor 500 Stock index (SP) for the corresponding 109-year period. In addition, a 3rd series was constructed, a price deflated Standard and Poor index (RSP) with a base period of 1870, to account for possible inflationary distortion of the index. The empirical results do not invalidate the hypothesis that population growth rates affect equity markets. In fact, there seems to be strong evidence that they are related in a manner suggestive of Keynes' intutition, namely, that the stock market crash of 1929 was due to factors more fundamental than those often perceived from a shortrun perspective. According to Keynes (1937), population is the most

  15. Mega-Planning in Population

    ERIC Educational Resources Information Center

    Clark, Sarah C.; Murray, Margo

    2005-01-01

    Clark and Murray examine the six Critical Performance Factors for Mega planning in an example drawn from the five-year history of the population program of a major west coast philanthropy. In this article, the authors describe the salience and scope of the population issue as it is relates to other global trends; the steps the foundation took to…

  16. American Indian Population Statistics.

    ERIC Educational Resources Information Center

    Thomason, Timothy C., Ed.

    This report summarizes American Indian and Alaska Native (AI/AN) population statistics from the 1990 Census. In 1990 there were about 2 million persons who identified themselves as American Indians in the United States, a 38 percent increase over the 1980 census. More than half of the Indian population lived in six states, with Oklahoma having the…

  17. The World Population Dilemma.

    ERIC Educational Resources Information Center

    Population Reference Bureau, Inc., Washington, DC.

    This book is the third in a series published by the Population Reference Bureau aimed at illuminating the facts and consequences of human population dynamics for secondary and college-age students. Many illustrations, charts and graphs are included in this volume to help the reader grasp a number of the current ideas and concepts that are used in…

  18. Frequently Asked Questions about Population.

    ERIC Educational Resources Information Center

    California Journal of Science Education, 2000

    2000-01-01

    Emphasizes the issue of human population growth. Provides information on current demographic trends; their social, economic, and environmental impacts; and Zero Population Growth's (ZPG) position on several controversial topics. (ASK)

  19. Population and development.

    PubMed

    Rao, S V

    1992-01-01

    A unified approach to development is recommended: one in which the social, economic, and political components are accounted for within a multidimensional process of reorganization and reorientation of structures and attitudes, customs, and beliefs. During the 1970s, development was construed as improvement in employment within a growing economy and elimination of poverty and inequality--a redistribution of growth. Development should increase and widen the distribution of basic life sustaining goods, increase levels of living, and expand economic and social choices and free people from dependence on other people and servitude to ignorance and poverty. Six basic issues linking population growth and development were identified; the interrelationships between economic, social, and demographic variables were explained. The aims of educational development and educational progress as affected by urbanization were discussed. It is inappropriate to isolate economic, social, and demographic concerns as separate entities and as separate from the development process. The population problem of rapid population growth is intertwined with the problem of unmet human needs; problematic are illiteracy, extreme deprivation, insufficient income to purchase essential health services and basic nutrition, and inadequate diets. Improvements have not kept pace with needs. The theories of Malthus are no longer germane, and demographic transition theory is not as effective in achieving or explaining the reduction of birth rates. An approach which attacks poverty and low quality of life would be directed to core motivations. The hidden momentum of population growth and the impact of literacy and age and sex composition are discussed as features of improvement in quality of life and of fertility reduction. Economic and social development are dependent on human resources, not on capital or material resources. The institutional mechanism for developing human potential is the educational system

  20. Shallow Population Genetic Structures of Thread-sail Filefish (Stephanolepis cirrhifer) Populations from Korean Coastal Waters.

    PubMed

    Yoon, M; Park, W; Nam, Y K; Kim, D S

    2012-02-01

    Genetic diversities, population genetic structures and demographic histories of the thread-sail filefish Stephanolepis cirrhifer were investigated by nucleotide sequencing of 336 base pairs of the mitochondrial DNA (mtDNA) control region in 111 individuals collected from six populations in Korean coastal waters. A total of 70 haplotypes were defined by 58 variable nucleotide sites. The neighbor-joining tree of the 70 haplotypes was shallow and did not provide evidence of geographical associations. Expansion of S. cirrhifer populations began approximate 51,000 to 102,000 years before present, correlating with the period of sea level rise since the late Pleistocene glacial maximum. High levels of haplotype diversities (0.974±0.029 to 1.000±0.076) and nucleotide diversities (0.014 to 0.019), and low levels of genetic differentiation among populations inferred from pairwise population F ST values (-0.007 to 0.107), support an expansion of the S. cirrhifer population. Hierarchical analysis of molecular variance (AMOVA) revealed weak but significant genetic structures among three groups (F CT = 0.028, p<0.05), and no genetic variation within groups (0.53%; F SC = 0.005, p = 0.23). These results may help establish appropriate fishery management strategies for stocks of S. cirrhifer and related species.

  1. Shallow Population Genetic Structures of Thread-sail Filefish (Stephanolepis cirrhifer) Populations from Korean Coastal Waters

    PubMed Central

    Yoon, M.; Park, W.; Nam, Y. K.; Kim, D. S.

    2012-01-01

    Genetic diversities, population genetic structures and demographic histories of the thread-sail filefish Stephanolepis cirrhifer were investigated by nucleotide sequencing of 336 base pairs of the mitochondrial DNA (mtDNA) control region in 111 individuals collected from six populations in Korean coastal waters. A total of 70 haplotypes were defined by 58 variable nucleotide sites. The neighbor-joining tree of the 70 haplotypes was shallow and did not provide evidence of geographical associations. Expansion of S. cirrhifer populations began approximate 51,000 to 102,000 years before present, correlating with the period of sea level rise since the late Pleistocene glacial maximum. High levels of haplotype diversities (0.974±0.029 to 1.000±0.076) and nucleotide diversities (0.014 to 0.019), and low levels of genetic differentiation among populations inferred from pairwise population FST values (−0.007 to 0.107), support an expansion of the S. cirrhifer population. Hierarchical analysis of molecular variance (AMOVA) revealed weak but significant genetic structures among three groups (FCT = 0.028, p<0.05), and no genetic variation within groups (0.53%; FSC = 0.005, p = 0.23). These results may help establish appropriate fishery management strategies for stocks of S. cirrhifer and related species. PMID:25049547

  2. Use of population-referenced total activity counts percentiles to assess and classify physical activity of population groups.

    PubMed

    Wolff-Hughes, Dana L; Troiano, Richard P; Boyer, William R; Fitzhugh, Eugene C; McClain, James J

    2016-06-01

    Population-referenced total activity counts per day (TAC/d) percentiles provide public health practitioners a standardized measure of physical activity (PA) volume obtained from an accelerometer that can be compared across populations. The purpose of this study was to describe the application of TAC/d population-referenced percentiles to characterize the PA levels of population groups relative to US estimates. A total of 679 adults participating in the 2011 NYC Physical Activity Transit survey wore an ActiGraph accelerometer on their hip for seven consecutive days. Accelerometer-derived TAC/d was classified into age- and gender-specific quartiles of US population-referenced TAC/d to compare differences in the distributions by borough (N=5). Males in Brooklyn, Manhattan, and Staten Island had significantly greater TAC/d than US males. Females in Brooklyn and Queens had significantly greater levels of TAC/d compared to US females. The proportion of males in each population-referenced TAC/d quartile varied significantly by borough (χ(2)(12)=2.63, p=0.002), with disproportionately more men in Manhattan and the Bronx found to be in the highest and lowest US population-referenced TAC/d quartiles, respectively. For females, there was no significant difference in US population-reference TAC/d quartile by borough (χ(2)(12)=1.09, p=0.36). These results demonstrate the utility of population-referenced TAC/d percentiles in public health monitoring and surveillance. These findings also provide insights into the PA levels of NYC residents relative to the broader US population, which can be used to guide health promotion efforts. Published by Elsevier Inc.

  3. Use of population-referenced total activity counts percentiles to assess and classify physical activity of population groups

    PubMed Central

    Wolff-Hughes, Dana L.; Troiano, Richard P.; Boyer, William R.; Fitzhugh, Eugene C.; McClain, James J.

    2016-01-01

    Objectives Population-referenced total activity counts per day (TAC/d) percentiles provide public health practitioners a standardized measure of physical activity (PA) volume obtained from an accelerometer that can be compared across populations. The purpose of this study was to describe the application of TAC/d population-referenced percentiles to characterize the PA levels of population groups relative to US estimates. Methods A total of 679 adults participating in the 2011 NYC Physical Activity Transit survey wore an ActiGraph accelerometer on their hip for seven consecutive days. Accelerometer-derived TAC/d was classified into age- and gender-specific quartiles of US population-referenced TAC/d to compare differences in the distributions by borough (N=5). Results Males in Brooklyn, Manhattan, and Staten Island had significantly greater TAC/d than US males. Females in Brooklyn and Queens had significantly greater levels of TAC/d compared to US females. The proportion of males in each population-referenced TAC/d quartile varied significantly by borough (χ2(12)=2.63, p=0.002), with disproportionately more men in Manhattan and the Bronx found to be in the highest and lowest US population-referenced TAC/d quartiles, respectively. For females, there was no significant difference in US population-reference TAC/d quartile by borough (χ2(12)=1.09, p=0.36). Conclusions These results demonstrate the utility of population-referenced TAC/d percentiles in public health monitoring and surveillance. These findings also provide insights into the PA levels of NYC residents relative to the broader US population, which can be used to guide health promotion efforts. PMID:26876630

  4. Population dynamics and angler exploitation of the unique muskellunge population in Shoepack Lake, Voyageurs National Park, Minnesota

    USGS Publications Warehouse

    Frohnauer, N.K.; Pierce, C.L.; Kallemeyn, L.W.

    2007-01-01

    A unique population of muskellunge Esox masquinongy inhabits Shoepack Lake in Voyageurs National Park, Minnesota. Little is known about its status, dynamics, and angler exploitation, and there is concern for the long-term viability of this population. We used intensive sampling and mark-recapture methods to quantify abundance, survival, growth, condition, age at maturity and fecundity and angler surveys to quantify angler pressure, catch rates, and exploitation. During our study, heavy rain washed out a dam constructed by beavers Castor canadensis which regulates the water level at the lake outlet, resulting in a nearly 50% reduction in surface area. We estimated a population size of 1,120 adult fish at the beginning of the study. No immediate reduction in population size was detected in response to the loss of lake area, although there was a gradual, but significant, decline in population size over the 2-year study. Adults grew less than 50 mm per year, and relative weight (W r) averaged roughly 80. Anglers were successful in catching, on average, two fish during a full day of angling, but harvest was negligible. Shoepack Lake muskellunge exhibit much slower growth rates and lower condition, but much higher densities and angler catch per unit effort (CPUE), than other muskellunge populations. The unique nature, limited distribution, and location of this population in a national park require special consideration for management. The results of this study provide the basis for assessing the long-term viability of the Shoepack Lake muskellunge population through simulations of long-term population dynamics and genetically effective population size. ?? Copyright by the American Fisheries Society 2007.

  5. Human Population: Fundamentals of Growth and Change.

    ERIC Educational Resources Information Center

    Stauffer, Cheryl Lynn, Ed.

    This booklet focuses on eight elements of population dynamics: "Population Growth and Distribution"; "Natural Increase and Future Growth"; "Effect of Migration on Population Growth"; "Three Patterns of Population Change"; "Patterns of World Urbanization"; "The Status of Women";…

  6. EVALUATING HABITAT AS A SURROGATE FOR POPULATION VIABILITY USING A SPATIALLY EXPLICIT POPULATION MODEL

    EPA Science Inventory

    Because data for conservation planning are always limited, surrogates are often substituted for intractable measurements such as species richness or population viability. We examined the ability of habitat quality to act as a surrogate for population performance for both Red-sho...

  7. Variation among Populations of Belonolaimus longicaudatus.

    PubMed

    Robbins, R T; Hirschmann, H

    1974-04-01

    Three North Carolina populations of Belonolairnus longicaudatus differed significantly from three Georgia populations in stylet measurements, the c ratio, the distance of the excretory pore from the anterior end for both sexes; the a ratio for females only; and the total body length, tail length, and spicule length for males only. The Georgia nematodes were stouter, and the females possessed sclerotized vaginal pieces. The distal portion of the spicules of North Carolina males had an indentation and hump lacking in those of the Georgia males. The haploid number of chromosomes was eight for males from all populations of B. longicaudatus and a North Carolina population of B. maritimus. Interpopulation matings of the Tarboro, N.C. and Tifton, Ga. populations indicated that the offspring produced were infertile. Morphological differences and reproductive isolation suggest that the North Carolina and the Georgia populations belong to different species.

  8. Chinstrap penguin population genetic structure: one or more populations along the Southern Ocean?

    PubMed

    Mura-Jornet, Isidora; Pimentel, Carolina; Dantas, Gisele P M; Petry, Maria Virginia; González-Acuña, Daniel; Barbosa, Andrés; Lowther, Andrew D; Kovacs, Kit M; Poulin, Elie; Vianna, Juliana A

    2018-06-13

    Historical factors, demography, reproduction and dispersal are crucial in determining the genetic structure of seabirds. In the Antarctic marine environment, penguins are a major component of the avian biomass, dominant predators and important bioindicators of ecological change. Populations of chinstrap penguins have decreased in nearly all their breeding sites, and their range is expanding throughout the Antarctic Peninsula. Population genetic structure of this species has been studied in some colonies, but not between breeding colonies in the Antarctic Peninsula or at the species' easternmost breeding colony (Bouvetøya). Connectivity, sex-biased dispersal, diversity, genetic structure and demographic history were studied using 12 microsatellite loci and a mitochondrial DNA region (HVRI) in 12 breeding colonies in the South Shetland Islands (SSI) and the Western Antarctic Peninsula (WAP), and one previously unstudied sub-Antarctic island, 3600 km away from the WAP (Bouvetøya). High genetic diversity, evidence of female bias-dispersal and a sign of population expansion after the last glacial maximum around 10,000 mya were detected. Limited population genetic structure and lack of isolation by distance throughout the region were found, along with no differentiation between the WAP and Bouvetøya (overall microsatellite F ST  = 0.002, p = 0.273; mtDNA F ST  = - 0.004, p = 0.766), indicating long distance dispersal. Therefore, genetic assignment tests could not assign individuals to their population(s) of origin. The most differentiated location was Georges Point, one of the southernmost breeding colonies of this species in the WAP. The subtle differentiation found may be explained by some combination of low natal philopatric behavior, high rates of dispersal and/or generally high mobility among colonies of chinstrap penguins compared to other Pygoscelis species.

  9. Population Education in the United States: A Report to the Commission on Population Growth and the American Future.

    ERIC Educational Resources Information Center

    Viederman, Stephen

    Population education is a planned, integrated, and sequential approach to population learning. It is defined as the process by which the student investigates the nature and meaning of population processes and characteristics, the causes of population changes, and the consequences of these for himself, his family, his society, and the world. Its…

  10. Population Structure of Pseudocercospora fijiensis in Costa Rica Reveals Shared Haplotype Diversity with Southeast Asian Populations.

    PubMed

    Saville, Amanda; Charles, Melodi; Chavan, Suchitra; Muñoz, Miguel; Gómez-Alpizar, Luis; Ristaino, Jean Beagle

    2017-12-01

    Pseudocercospora fijiensis is the causal pathogen of black Sigatoka, a devastating disease of banana that can cause 20 to 80% yield loss in the absence of fungicides in banana crops. The genetic structure of populations of P. fijiensis in Costa Rica was examined and compared with Honduran and global populations to better understand migration patterns and inform management strategies. In total, 118 isolates of P. fijiensis collected from Costa Rica and Honduras from 2010 to 2014 were analyzed using multilocus genotyping of six loci and compared with a previously published global dataset of populations of P. fijiensis. The Costa Rican and Honduran populations shared haplotype diversity with haplotypes from Southeast Asia, Oceania, and the Americas but not Africa for all but one of the six loci studied. Gene flow and shared haplotype diversity was found in Honduran and Costa Rican populations of the pathogen. The data indicate that the haplotypic diversity observed in Costa Rican populations of P. fijiensis is derived from dispersal from initial outbreak sources in Honduras and admixtures between genetically differentiated sources from Southeast Asia, Oceania, and the Americas.

  11. Africa: rapid population increase retards development.

    PubMed

    1993-10-01

    The Organization of African Unity (OAU), the African Development Bank (ADB) and the UN Economic Commission for Africa (ECA) have criticized African governments for not taking the problem of unchecked population growth seriously enough. "Until recently most African governments did not view rapid population growth as a matter for concern," said the OAU assistant secretary-general for political affairs, Machivenyika Mapuranga, at a seminar on 'population and development'. The OAU estimates that an annual average population increase of 3.1% far outstrips Africa's economic growth, which in 1992 was less than 1%. Mapuranga acknowledged that cutting the population increase is an uphill struggle, especially among rural communities. African agriculture is largely labor intensive, sustained by smallholders, which encourages farmers to have more children. Like other wage earners, African farmers look to support from their family when they grow old and, for that reason, the number of children also counts. But with agricultural production growing at an average annual rate of 2.5%, self-sufficiency in food remains an elusive goal. Cities in sub-Saharan Africa are growing much faster than the overall rate of population increase of 3.1% per year. Between 1980 and 1988 the region's urban population increased at the rate of 6.9% a year. Urban areas now account for nearly 30% of the sub-Saharan Africa population, currently put at 680 million. By 2025, approximately 700 million people are expected to live in urban areas. Despite migration to towns, the rural population is expected to rise more than 68%, reaching over 590 million. full text

  12. Microbial populations in contaminant plumes

    USGS Publications Warehouse

    Haack, S.K.; Bekins, B.A.

    2000-01-01

    Efficient biodegradation of subsurface contaminants requires two elements: (1) microbial populations with the necessary degradative capabilities, and (2) favorable subsurface geochemical and hydrological conditions. Practical constraints on experimental design and interpretation in both the hydrogeological and microbiological sciences have resulted in limited knowledge of the interaction between hydrogeological and microbiological features of subsurface environments. These practical constraints include: (1) inconsistencies between the scales of investigation in the hydrogeological and microbiological sciences, and (2) practical limitations on the ability to accurately define microbial populations in environmental samples. However, advances in application of small-scale sampling methods and interdisciplinary approaches to site investigations are beginning to significantly improve understanding of hydrogeological and microbiological interactions. Likewise, culture-based and molecular analyses of microbial populations in subsurface contaminant plumes have revealed significant adaptation of microbial populations to plume environmental conditions. Results of recent studies suggest that variability in subsurface geochemical and hydrological conditions significantly influences subsurface microbial-community structure. Combined investigations of site conditions and microbial-community structure provide the knowledge needed to understand interactions between subsurface microbial populations, plume geochemistry, and contaminant biodegradation.

  13. Global earthquake fatalities and population

    USGS Publications Warehouse

    Holzer, Thomas L.; Savage, James C.

    2013-01-01

    Modern global earthquake fatalities can be separated into two components: (1) fatalities from an approximately constant annual background rate that is independent of world population growth and (2) fatalities caused by earthquakes with large human death tolls, the frequency of which is dependent on world population. Earthquakes with death tolls greater than 100,000 (and 50,000) have increased with world population and obey a nonstationary Poisson distribution with rate proportional to population. We predict that the number of earthquakes with death tolls greater than 100,000 (50,000) will increase in the 21st century to 8.7±3.3 (20.5±4.3) from 4 (7) observed in the 20th century if world population reaches 10.1 billion in 2100. Combining fatalities caused by the background rate with fatalities caused by catastrophic earthquakes (>100,000 fatalities) indicates global fatalities in the 21st century will be 2.57±0.64 million if the average post-1900 death toll for catastrophic earthquakes (193,000) is assumed.

  14. Challenges in application of bioanalytical method on different populations and effect of population on PK.

    PubMed

    Kale, Prashant; Shukla, Manoj; Soni, Gunjan; Patel, Ronak; Gupta, Shailendra

    2014-01-01

    Prashant Kale has 22 years of immense experience in the analytical and bioanalytical domain. He is Senior Vice President, Bioequivalence Operations of Lambda Therapeutic Research, India which includes Bioanalytical, Clinics, Clinical data management, Pharmacokinetics and Biostatistics, Protocol writing, Clinical lab and Quality Assurance departments. He has been with Lambda for over 14 years. By qualification he is a M.Sc. and an MBA. Mr. Kale is responsible for the management, technical and administrative functions of the BE unit located at Ahmedabad and Mumbai, India. He is also responsible for leading the process of integration between bioanalytical laboratories and services offered by Lambda at global locations (India and Canada). Mr. Kale has faced several regulatory audits and inspections from leading regulatory bodies including but not limited to DCGI, USFDA, ANVISA, Health Canada, UK MHRA, Turkey MoH, WHO. There are many challenges involved in the application of bioanalytical method on different populations. This includes difference in equipment, material and environment across laboratories, variations in the matrix characteristics in different populations, differences in techniques between analysts such as sample processing and handling and others. Additionally, there is variability in the PK of a drug in different populations. This article shows the effect of different populations on validated bioanalytical method and on the PK of a drug. Hence, the bioanalytical method developed and validated for a specific population may need required modification when applied to another population. Critical consideration of all such aspects is the key to successful implementation of a validated method on different populations.

  15. Optimal control of Atlantic population Canada geese

    USGS Publications Warehouse

    Hauser, C.E.; Runge, M.C.; Cooch, E.G.; Johnson, F.A.; Harvey, W.F.

    2007-01-01

    Management of Canada geese (Branta canadensis) can be a balance between providing sustained harvest opportunity while not allowing populations to become overabundant and cause damage. In this paper, we focus on the Atlantic population of Canada geese and use stochastic dynamic programming to determine the optimal harvest strategy over a range of plausible models for population dynamics. There is evidence to suggest that the population exhibits significant age structure, and it is possible to reconstruct age structure from surveys. Consequently the harvest strategy is a function of the age composition, as well as the abundance, of the population. The objective is to maximize harvest while maintaining the number of breeding adults in the population between specified upper and lower limits. In addition, the total harvest capacity is limited and there is uncertainty about the strength of density-dependence. We find that under a density-independent model, harvest is maximized by maintaining the breeding population at the highest acceptable abundance. However if harvest capacity is limited, then the optimal long-term breeding population size is lower than the highest acceptable level, to reduce the risk of the population growing to an unacceptably large size. Under the proposed density-dependent model, harvest is maximized by maintaining the breeding population at an intermediate level between the bounds on acceptable population size; limits to harvest capacity have little effect on the optimal long-term population size. It is clear that the strength of density-dependence and constraints on harvest significantly affect the optimal harvest strategy for this population. Model discrimination might be achieved in the long term, while continuing to meet management goals, by adopting an adaptive management strategy.

  16. Stable, semi-stable populations and growth potential.

    PubMed

    Bourgeois-Pichat, J

    1971-07-01

    Abstract Starting from the definition of a Malthusian population given by Alfred J. Lotka, the author recalls how the concept of stable population is introduced in demography, first as a particular case of stable populations, and secondly as a limit of a demographic evolutionary process in which female age-specific fertility rates and age-specific mortality rates remain constant. Then he defines a new concept: the semi-stable population which is a population with a constant age distribution. He shows that such a population coincides at any point of time with the stable population corresponding to the mortality and the fertility at this point of time. In the remaining part of the paper it is shown how the concept of a stable population can be used for defining a coefficient of inertia which measures the resistance of a population to modification of its course as a consequence of changing fertility and mortality. Some formulae are established to calculate this coefficient first for an arbitrary population, and secondly for a semistable population. In this second case the formula is particularly simple. It appears as a product of three terms: the expectation of life at birth in years, the crude birth rate, and a coefficient depending on the rate of growth and for which a numerical table is easy to establish.

  17. Population-genetic comparison of the Sorbian isolate population in Germany with the German KORA population using genome-wide SNP arrays

    PubMed Central

    2011-01-01

    Background The Sorbs are an ethnic minority in Germany with putative genetic isolation, making the population interesting for disease mapping. A sample of N = 977 Sorbs is currently analysed in several genome-wide meta-analyses. Since genetic differences between populations are a major confounding factor in genetic meta-analyses, we compare the Sorbs with the German outbred population of the KORA F3 study (N = 1644) and other publically available European HapMap populations by population genetic means. We also aim to separate effects of over-sampling of families in the Sorbs sample from effects of genetic isolation and compare the power of genetic association studies between the samples. Results The degree of relatedness was significantly higher in the Sorbs. Principal components analysis revealed a west to east clustering of KORA individuals born in Germany, KORA individuals born in Poland or Czech Republic, Half-Sorbs (less than four Sorbian grandparents) and Full-Sorbs. The Sorbs cluster is nearest to the cluster of KORA individuals born in Poland. The number of rare SNPs is significantly higher in the Sorbs sample. FST between KORA and Sorbs is an order of magnitude higher than between different regions in Germany. Compared to the other populations, Sorbs show a higher proportion of individuals with runs of homozygosity between 2.5 Mb and 5 Mb. Linkage disequilibrium (LD) at longer range is also slightly increased but this has no effect on the power of association studies. Oversampling of families in the Sorbs sample causes detectable bias regarding higher FST values and higher LD but the effect is an order of magnitude smaller than the observed differences between KORA and Sorbs. Relatedness in the Sorbs also influenced the power of uncorrected association analyses. Conclusions Sorbs show signs of genetic isolation which cannot be explained by over-sampling of relatives, but the effects are moderate in size. The Slavonic origin of the Sorbs is still

  18. Population changes in residential clusters in Japan.

    PubMed

    Sekiguchi, Takuya; Tamura, Kohei; Masuda, Naoki

    2018-01-01

    Population dynamics in urban and rural areas are different. Understanding factors that contribute to local population changes has various socioeconomic and political implications. In the present study, we use population census data in Japan to examine contributors to the population growth of residential clusters between years 2005 and 2010. The data set covers the entirety of Japan and has a high spatial resolution of 500 × 500 m2, enabling us to examine population dynamics in various parts of the country (urban and rural) using statistical analysis. We found that, in addition to the area, population density, and age, the shape of the cluster and the spatial distribution of inhabitants within the cluster are significantly related to the population growth rate of a residential cluster. Specifically, the population tends to grow if the cluster is "round" shaped (given the area) and the population is concentrated near the center rather than periphery of the cluster. Combination of the present results and analysis framework with other factors that have been omitted in the present study, such as migration, terrain, and transportation infrastructure, will be fruitful.

  19. Who and what is a "population"? Historical debates, current controversies, and implications for understanding "population health" and rectifying health inequities.

    PubMed

    Krieger, Nancy

    2012-12-01

    The idea of "population" is core to the population sciences but is rarely defined except in statistical terms. Yet who and what defines and makes a population has everything to do with whether population means are meaningful or meaningless, with profound implications for work on population health and health inequities. In this article, I review the current conventional definitions of, and historical debates over, the meaning(s) of "population," trace back the contemporary emphasis on populations as statistical rather than substantive entities to Adolphe Quetelet's powerful astronomical metaphor, conceived in the 1830s, of l'homme moyen (the average man), and argue for an alternative definition of populations as relational beings. As informed by the ecosocial theory of disease distribution, I then analyze several case examples to explore the utility of critical population-informed thinking for research, knowledge, and policy involving population health and health inequities. Four propositions emerge: (1) the meaningfulness of means depends on how meaningfully the populations are defined in relation to the inherent intrinsic and extrinsic dynamic generative relationships by which they are constituted; (2) structured chance drives population distributions of health and entails conceptualizing health and disease, including biomarkers, as embodied phenotype and health inequities as historically contingent; (3) persons included in population health research are study participants, and the casual equation of this term with "study population" should be avoided; and (4) the conventional cleavage of "internal validity" and "generalizability" is misleading, since a meaningful choice of study participants must be in relation to the range of exposures experienced (or not) in the real-world societies, that is, meaningful populations, of which they are a part. To improve conceptual clarity, causal inference, and action to promote health equity, population sciences need to expand

  20. Population problems in Austronesia.

    PubMed

    Hull, T H

    1986-11-01

    The author examines population issues facing countries in Oceania and Southeastern Asia. "Analysis is based on recently released population projections from the United Nations Population Division. There are great differences among the countries.... There are nonetheless important areas of commonality: all nations are facing the problem of raising levels of schooling in line with parents' aspirations and economic needs, all face problems of caring for a rising proportion of aged, and all have difficulties with the monitoring and control of international migration. Also, since minority groups in many countries are majority polities in neighbouring states, there is potential for establishing international dialogues aimed at relieving internal tensions." Consideration is given to the role of Australia in promoting international cooperation to deal with these issues. excerpt

  1. Population growth rates: issues and an application.

    PubMed Central

    Godfray, H Charles J; Rees, Mark

    2002-01-01

    Current issues in population dynamics are discussed in the context of The Royal Society Discussion Meeting 'Population growth rate: determining factors and role in population regulation'. In particular, different views on the centrality of population growth rates to the study of population dynamics and the role of experiments and theory are explored. Major themes emerging include the role of modern statistical techniques in bringing together experimental and theoretical studies, the importance of long-term experimentation and the need for ecology to have model systems, and the value of population growth rate as a means of understanding and predicting population change. The last point is illustrated by the application of a recently introduced technique, integral projection modelling, to study the population growth rate of a monocarpic perennial plant, its elasticities to different life-history components and the evolution of an evolutionarily stable strategy size at flowering. PMID:12396521

  2. Population Geography: Problems, Concepts, and Prospects.

    ERIC Educational Resources Information Center

    Peters, Gary L.; Larkin, Robert P.

    This book introduces secondary students to population geography. Material from other disciplines is included because the study of population is multidisciplinary. It is presented in eleven chapters. The introduction considers definitions of concepts and aspects of population geography, explaining the emphasis on spatial patterns of population…

  3. Population genetic analysis of insertion-deletion polymorphisms in a Brazilian population using the Investigator DIPplex kit.

    PubMed

    Ferreira Palha, Teresinha de Jesus Brabo; Ribeiro Rodrigues, Elzemar Martins; Cavalcante, Giovanna Chaves; Marrero, Andrea; de Souza, Ilíada Rainha; Seki Uehara, Clineu Julien; Silveira da Motta, Carlos Henrique Ares; Koshikene, Daniela; da Silva, Dayse Aparecida; de Carvalho, Elizeu Fagundes; Chemale, Gustavo; Freitas, Jorge M; Alexandre, Lídia; Paranaiba, Renato T F; Soler, Mirella Perruccio; Santos, Sidney

    2015-11-01

    The aim of this study was to estimate the diversity of 30 insertion/deletion (INDEL) markers (Investigator(®) DIPplex kit) in a sample of 519 individuals from six Brazilian states and to evaluate their applicability in forensic genetics. All INDEL markers were found to be highly polymorphic in the Brazilian population and were in Hardy-Weinberg equilibrium. To determine their forensic suitability in the Brazilian population, the markers were evaluated for discrimination power, match probability and exclusion power. The combined discrimination power (CDP), combined match power (CMP) and combined power of exclusion (CPE) were higher than 0.999999, 3.4 × 10(-13) and 0.9973, respectively. Further comparison of 29 worldwide populations revealed significant genetic differences between continental populations and a closer relationship between the Brazilian and European populations. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  4. Moving the Dial to Advance Population Health Equity in New York City Asian American Populations

    PubMed Central

    Trinh-Shevrin, Chau; Kwon, Simona C.; Nadkarni, Smiti Kapadia; Islam, Nadia S.

    2015-01-01

    The shift toward a health equity framework for eliminating the health disparities burden of racial/ethnic minority populations has moved away from a disease-focused model to a social determinants framework that aims to achieve the highest attainment of health for all. The New York University Center for the Study of Asian American Health (CSAAH) has identified core themes and strategies for advancing population health equity for Asian American populations in New York City that are rooted in the following: social determinants of health; multisectoral, community-engaged approaches; leveraging community assets; improved disaggregated data collection and access to care; and building sustainability through community leadership and infrastructure-building activities. We describe the strategies CSAAH employed to move the dial on population health equity. PMID:25905858

  5. Population dynamics in an intermittent refuge

    NASA Astrophysics Data System (ADS)

    Colombo, E. H.; Anteneodo, C.

    2016-10-01

    Population dynamics is constrained by the environment, which needs to obey certain conditions to support population growth. We consider a standard model for the evolution of a single species population density, which includes reproduction, competition for resources, and spatial spreading, while subject to an external harmful effect. The habitat is spatially heterogeneous, there existing a refuge where the population can be protected. Temporal variability is introduced by the intermittent character of the refuge. This scenario can apply to a wide range of situations, from a laboratory setting where bacteria can be protected by a blinking mask from ultraviolet radiation, to large-scale ecosystems, like a marine reserve where there can be seasonal fishing prohibitions. Using analytical and numerical tools, we investigate the asymptotic behavior of the total population as a function of the size and characteristic time scales of the refuge. We obtain expressions for the minimal size required for population survival, in the slow and fast time scale limits.

  6. Population density and youth antisocial behavior.

    PubMed

    Harden, K Paige; D'Onofrio, Brian M; Van Hulle, Carol; Turkheimer, Eric; Rodgers, Joseph L; Waldman, Irwin D; Lahey, Benjamin B

    2009-08-01

    Theoretical models concerning how neighborhood contexts adversely influence juvenile antisocial behavior frequently focus on urban neighborhoods; however, previous studies comparing urban and rural areas on the prevalence of youth antisocial behavior have yielded mixed results. The current study uses longitudinal data on the offspring of a nationally representative sample of mothers (N = 4,886) in the US. There was no relation between density and mother-reported child conduct problems across ages 4-13 years, but youth living in areas of greater population density exhibited more youth self-reported delinquency across 10-17 years. Families often moved to counties with greater or lesser population density, but longitudinal analyses treating population density as a time-varying covariate did not support the hypothesis that living in densely populated counties influenced youth delinquency. Rather, the association between population density and delinquency appears to be due to unmeasured selection variables that differ between families who live in more or less densely populated counties.

  7. Genetic Population Structure of Tectura paleacea: Implications for the Mechanisms Regulating Population Structure in Patchy Coastal Habitats

    PubMed Central

    Begovic, Emina; Lindberg, David R.

    2011-01-01

    The seagrass limpet Tectura paleacea (Gastropoda; Patellogastropoda) belongs to a seagrass obligate lineage that has shifted from the Caribbean in the late Miocene, across the Isthmus of Panama prior to the closing of the Panamanian seaway, and then northward to its modern Baja California – Oregon distribution. To address whether larval entrainment by seagrass beds contributes to population structuring, populations were sampled at six California/Oregon localities approximately 2 degrees latitude apart during two post-settlement periods in July 2002 and June 2003. Partial cytochrome oxidase b (Cytb) sequences were obtained from 20 individuals (10 per year) from each population in order to determine the levels of population subdivision/connectivity. From the 120 individuals sequenced, there were eighty-one unique haplotypes, with the greatest haplotype diversity occurring in southern populations. The only significant genetic break detected was consistent with a peri-Point Conception (PPC) biogeographic boundary while populations north and south of Point Conception were each panmictic. The data further indicate that populations found south of the PPC biogeographic boundary originated from northern populations. This pattern of population structure suggests that seagrass patches are not entraining the larvae of T. paleacea by altering flow regimes within their environment; a process hypothesized to produce extensive genetic subdivision on fine geographic scales. In contrast to the haplotype data, morphological patterns vary significantly over very fine geographic scales that are inconsistent with the observed patterns of genetic population structure, indicating that morphological variation in T. paleacea might be attributed to differential ecophenotypic expression in response to local habitat variability throughout its distribution. These results suggest that highly localized conservation efforts may not be as effective as large-scale conservation efforts in near

  8. Genetic diversity and population structure of Scottish Highland red deer (Cervus elaphus) populations: a mitochondrial survey.

    PubMed

    Pérez-Espona, S; Pérez-Barbería, F J; Goodall-Copestake, W P; Jiggins, C D; Gordon, I J; Pemberton, J M

    2009-02-01

    The largest population of red deer (Cervus elaphus) in Europe is found in Scotland. However, human impacts through hunting and introduction of foreign deer stock have disturbed the population's genetics to an unknown extent. In this study, we analysed mitochondrial control region sequences of 625 individuals to assess signatures of human and natural historical influence on the genetic diversity and population structure of red deer in the Scottish Highlands. Genetic diversity was high with 74 haplotypes found in our study area (115 x 87 km). Phylogenetic analyses revealed that none of the individuals had introgressed mtDNA from foreign species or subspecies of deer and only suggested a very few localized red deer translocations among British localities. A haplotype network and population analyses indicated significant genetic structure (Phi(ST)=0.3452, F(ST)=0.2478), largely concordant with the geographical location of the populations. Mismatch distribution analysis and neutrality tests indicated a significant population expansion for one of the main haplogroups found in the study area, approximately dated c. 8200 or 16 400 years ago when applying a fast or slow mutation rate, respectively. Contrary to general belief, our results strongly suggest that native Scottish red deer mtDNA haplotypes have persisted in the Scottish Highlands and that the population retains a largely natural haplotype diversity and structure in our study area.

  9. Evolutionary dynamics of cooperation in neutral populations

    NASA Astrophysics Data System (ADS)

    Szolnoki, Attila; Perc, Matjaž

    2018-01-01

    Cooperation is a difficult proposition in the face of Darwinian selection. Those that defect have an evolutionary advantage over cooperators who should therefore die out. However, spatial structure enables cooperators to survive through the formation of homogeneous clusters, which is the hallmark of network reciprocity. Here we go beyond this traditional setup and study the spatiotemporal dynamics of cooperation in a population of populations. We use the prisoner's dilemma game as the mathematical model and show that considering several populations simultaneously gives rise to fascinating spatiotemporal dynamics and pattern formation. Even the simplest assumption that strategies between different populations are payoff-neutral with one another results in the spontaneous emergence of cyclic dominance, where defectors of one population become prey of cooperators in the other population, and vice versa. Moreover, if social interactions within different populations are characterized by significantly different temptations to defect, we observe that defectors in the population with the largest temptation counterintuitively vanish the fastest, while cooperators that hang on eventually take over the whole available space. Our results reveal that considering the simultaneous presence of different populations significantly expands the complexity of evolutionary dynamics in structured populations, and it allows us to understand the stability of cooperation under adverse conditions that could never be bridged by network reciprocity alone.

  10. 45 CFR 1356.81 - Reporting population.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., DEPARTMENT OF HEALTH AND HUMAN SERVICES THE ADMINISTRATION ON CHILDREN, YOUTH AND FAMILIES, FOSTER CARE... by the State agency during the reporting period. (b) Baseline population. Each youth who is in foster... § 1356.81 Reporting population. The reporting population is comprised of all youth in the following...

  11. Population Education in Africa. English Version.

    ERIC Educational Resources Information Center

    Sankale-Semeteys, Eva, Ed.

    1985-01-01

    National conferences on population and development have recommended the integration of population issues into development planning by national governments. This book presents several ideas of practitioners in the field of population and family life education. Five articles in Part I focus on solutions to problems of introducing population…

  12. Adam Smith on population.

    PubMed

    Spengler, J J

    1970-11-01

    Abstract Adam Smith dealt with questions of population mainly in his Wealth of Nations. His discussion falls roughly under five heads and reflects in considerable measure his image of the English economy. (1) A country's population capacity, given the average level of consumption, was conditioned by the stock of land, the skill with which it was cultivated, and the degree to which division of labour could be increased and thereby augment output for domestic use and sale in external markets. (2) Growth of population was essentially in response to growth of the demand for labour and served to increase division of labour. (3) The social mechanisms underlying elevation of the scale of living are touched upon, and in an optimistic spirit. (4) The distribution of a country's population responded to its progress in opulence, with the rate of this progress conditioned by the degree to which inappropriate (e.g. mercantilist) policies were avoided. (5) Smith dealt briefly with such matters as colonies, education, size of economy, environmental influences, and public policy, all of which he recognized as significant for the quantity and quality of a country's numbers.

  13. Reconstructing Druze population history

    PubMed Central

    Marshall, Scarlett; Das, Ranajit; Pirooznia, Mehdi; Elhaik, Eran

    2016-01-01

    The Druze are an aggregate of communities in the Levant and Near East living almost exclusively in the mountains of Syria, Lebanon and Israel whose ~1000 year old religion formally opposes mixed marriages and conversions. Despite increasing interest in genetics of the population structure of the Druze, their population history remains unknown. We investigated the genetic relationships between Israeli Druze and both modern and ancient populations. We evaluated our findings in light of three hypotheses purporting to explain Druze history that posit Arabian, Persian or mixed Near Eastern-Levantine roots. The biogeographical analysis localised proto-Druze to the mountainous regions of southeastern Turkey, northern Iraq and southeast Syria and their descendants clustered along a trajectory between these two regions. The mixed Near Eastern–Middle Eastern localisation of the Druze, shown using both modern and ancient DNA data, is distinct from that of neighbouring Syrians, Palestinians and most of the Lebanese, who exhibit a high affinity to the Levant. Druze biogeographic affinity, migration patterns, time of emergence and genetic similarity to Near Eastern populations are highly suggestive of Armenian-Turkish ancestries for the proto-Druze. PMID:27848937

  14. Reconstructing Druze population history.

    PubMed

    Marshall, Scarlett; Das, Ranajit; Pirooznia, Mehdi; Elhaik, Eran

    2016-11-16

    The Druze are an aggregate of communities in the Levant and Near East living almost exclusively in the mountains of Syria, Lebanon and Israel whose ~1000 year old religion formally opposes mixed marriages and conversions. Despite increasing interest in genetics of the population structure of the Druze, their population history remains unknown. We investigated the genetic relationships between Israeli Druze and both modern and ancient populations. We evaluated our findings in light of three hypotheses purporting to explain Druze history that posit Arabian, Persian or mixed Near Eastern-Levantine roots. The biogeographical analysis localised proto-Druze to the mountainous regions of southeastern Turkey, northern Iraq and southeast Syria and their descendants clustered along a trajectory between these two regions. The mixed Near Eastern-Middle Eastern localisation of the Druze, shown using both modern and ancient DNA data, is distinct from that of neighbouring Syrians, Palestinians and most of the Lebanese, who exhibit a high affinity to the Levant. Druze biogeographic affinity, migration patterns, time of emergence and genetic similarity to Near Eastern populations are highly suggestive of Armenian-Turkish ancestries for the proto-Druze.

  15. The containment of world population growth.

    PubMed

    Caldwell, J C

    1975-12-01

    The world has reached the present position of unprecedentedly rapid population growth not by achieving uniquely high fertility but by bringing about extraordinarily low mortality. The high growth rate and the built-in momentum of the age structure are obstacles to achievement of an acceptable standard of living for most of the world's population. Although government population programs have the potential to curb this growth rate, this potential has not been realized, and such programs are too often perceived both by their administrators and the population concerned as an end in themselves rather than a means toward a better standard of living. It is in this latter perspective, and in the context of the total development process, that population programs should be implemented.

  16. Copy Number Variation across European Populations

    PubMed Central

    Chen, Wanting; Hayward, Caroline; Wright, Alan F.; Hicks, Andrew A.; Vitart, Veronique; Knott, Sara; Wild, Sarah H.; Pramstaller, Peter P.; Wilson, James F.; Rudan, Igor; Porteous, David J.

    2011-01-01

    Genome analysis provides a powerful approach to test for evidence of genetic variation within and between geographical regions and local populations. Copy number variants which comprise insertions, deletions and duplications of genomic sequence provide one such convenient and informative source. Here, we investigate copy number variants from genome wide scans of single nucleotide polymorphisms in three European population isolates, the island of Vis in Croatia, the islands of Orkney in Scotland and the South Tyrol in Italy. We show that whereas the overall copy number variant frequencies are similar between populations, their distribution is highly specific to the population of origin, a finding which is supported by evidence for increased kinship correlation for specific copy number variants within populations. PMID:21829696

  17. 40 CFR 68.30 - Defining offsite impacts-population.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 16 2014-07-01 2014-07-01 false Defining offsite impacts-population... impacts—population. (a) The owner or operator shall estimate in the RMP the population within a circle... defined in § 68.22(a). (b) Population to be defined. Population shall include residential population. The...

  18. 40 CFR 68.30 - Defining offsite impacts-population.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 16 2013-07-01 2013-07-01 false Defining offsite impacts-population... impacts—population. (a) The owner or operator shall estimate in the RMP the population within a circle... defined in § 68.22(a). (b) Population to be defined. Population shall include residential population. The...

  19. 40 CFR 68.30 - Defining offsite impacts-population.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 15 2011-07-01 2011-07-01 false Defining offsite impacts-population... impacts—population. (a) The owner or operator shall estimate in the RMP the population within a circle... defined in § 68.22(a). (b) Population to be defined. Population shall include residential population. The...

  20. 40 CFR 68.30 - Defining offsite impacts-population.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 16 2012-07-01 2012-07-01 false Defining offsite impacts-population... impacts—population. (a) The owner or operator shall estimate in the RMP the population within a circle... defined in § 68.22(a). (b) Population to be defined. Population shall include residential population. The...

  1. Genetic diversity of the Tibetan antelope (Pantholops hodgsonii) population of Ladakh, India, its relationship with other populations and conservation implications.

    PubMed

    Ahmad, Khursheed; Kumar, Ved P; Joshi, Bheem Dutt; Raza, Mohamed; Nigam, Parag; Khan, Anzara Anjum; Goyal, Surendra P

    2016-10-21

    The Tibetan antelope (Pantholops hodgsonii), or chiru, is an endangered antelope, distributed in China [Xinjiang, Xizang, Qinghai, Zhuolaihu Lake (Breeding habitat)], and India (Aksai Chin and Ladakh). There is a global demand for the species prized wool, which is used in weaving shahtoosh shawls. Over the years, the population of the Tibetan antelope has drastically declined from more than a million to a few thousand individuals, mainly due to poaching. Field studies undertaken in Ladakh, India also indicated winter migration of the population to Tibet. Migration between winter and calving habitats is well established to be female-biased across the Qinghai Tibetan Plateau (QTP). For effective conservation planning, genetic characterization is considered the best way to understand the likely impact of threats for ensuring the long-term viability of the population. In this regard, genetic characteristics of all Chinese populations are well-studied using mitochondrial and microsatellite markers, but information is lacking for the Indian population. Therefore, using the control region marker, we document for the first time the genetic variation of the Indian population of the Tibetan antelope, the extent of migration and its relationships with other populations of China. The partial fragment of control region (259 bp) marker was successfully amplified in 30 Tibetan antelope samples that were collected from the Chang Chenmo Valley in eastern Ladakh, India. We also retrieved control region sequences (n = 88) available in the public domain from GenBank of different Chinese populations. Low levels of nucleotide (π; 0.004) and haplotype (hd; 0.543) diversity were observed in the Indian population when compared to Chinese populations (π = 0.01357-0.02048 and hd = 0.889-0.986). Commonly used indices (Tajima's D and Fu's Fs) were analyzed for inferring the demographic history of the Indian populations, and all values were negative indicating population expansion or

  2. Statistical Physics of Population Genetics in the Low Population Size Limit

    NASA Astrophysics Data System (ADS)

    Atwal, Gurinder

    The understanding of evolutionary processes lends itself naturally to theory and computation, and the entire field of population genetics has benefited greatly from the influx of methods from applied mathematics for decades. However, in spite of all this effort, there are a number of key dynamical models of evolution that have resisted analytical treatment. In addition, modern DNA sequencing technologies have magnified the amount of genetic data available, revealing an excess of rare genetic variants in human genomes, challenging the predictions of conventional theory. Here I will show that methods from statistical physics can be used to model the distribution of genetic variants, incorporating selection and spatial degrees of freedom. In particular, a functional path-integral formulation of the Wright-Fisher process maps exactly to the dynamics of a particle in an effective potential, beyond the mean field approximation. In the small population size limit, the dynamics are dominated by instanton-like solutions which determine the probability of fixation in short timescales. These results are directly relevant for understanding the unusual genetic variant distribution at moving frontiers of populations.

  3. The Dynamics of Population, Built-up Areas and their Evolving Associations in Gridded Population across Time and Space

    NASA Astrophysics Data System (ADS)

    Stevens, F. R.; Gaughan, A. E.; Tatem, A. J.; Linard, C.; Sorichetta, A.; Nieves, J. J.; Reed, P.

    2017-12-01

    Gridded population data is commonly used to understand the `now' of hazard risk and mitigation management, health and disease modelling, and global change-, economic-, environmental-, and sustainability-related research. But to understand how human population change at local to global scales influences and is influenced by environmental changes requires novel ways of treating data and statistically describing associations of measured population counts with associated covariates. One of the most critical components in such gridded estimates is the relationship between built-up areas and population located in these areas. This relationship is rarely static and accurately estimating changes in built-areas through time and the changing human population around them is critical when applying gridded population datasets in studies of other environmental change. The research presented here discusses these issues in the context of multitemporal, gridded population data, using new technologies and sources of remotely-sensed and modeled built-up areas. We discuss applications of these data in environmental analyses and intercomparisons with other such data across scales.

  4. Variation in MHC genotypes in two populations of house sparrow (Passer domesticus) with different population histories.

    PubMed

    Borg, Asa Alexandra; Pedersen, Sindre Andre; Jensen, Henrik; Westerdahl, Helena

    2011-10-01

    Small populations are likely to have a low genetic ability for disease resistance due to loss of genetic variation through inbreeding and genetic drift. In vertebrates, the highest genetic diversity of the immune system is located at genes within the major histocompatibility complex (MHC). Interestingly, parasite-mediated selection is thought to potentially maintain variation at MHC loci even in populations that are monomorphic at other loci. Therefore, general loss of genetic variation in the genome may not necessarily be associated with low variation at MHC loci. We evaluated inter- and intrapopulation variation in MHC genotypes between an inbred (Aldra) and a relatively outbred population (Hestmannøy) of house sparrows (Passer domesticus) in a metapopulation at Helgeland, Norway. Genomic (gDNA) and transcribed (cDNA) alleles of functional MHC class I and IIB loci, along with neutral noncoding microsatellite markers, were analyzed to obtain relevant estimates of genetic variation. We found lower allelic richness in microsatellites in the inbred population, but high genetic variation in MHC class I and IIB loci in both populations. This suggests that also the inbred population could be under balancing selection to maintain genetic variation for pathogen resistance.

  5. Variation in MHC genotypes in two populations of house sparrow (Passer domesticus) with different population histories

    PubMed Central

    Borg, Åsa Alexandra; Pedersen, Sindre Andre; Jensen, Henrik; Westerdahl, Helena

    2011-01-01

    Small populations are likely to have a low genetic ability for disease resistance due to loss of genetic variation through inbreeding and genetic drift. In vertebrates, the highest genetic diversity of the immune system is located at genes within the major histocompatibility complex (MHC). Interestingly, parasite-mediated selection is thought to potentially maintain variation at MHC loci even in populations that are monomorphic at other loci. Therefore, general loss of genetic variation in the genome may not necessarily be associated with low variation at MHC loci. We evaluated inter- and intrapopulation variation in MHC genotypes between an inbred (Aldra) and a relatively outbred population (Hestmannøy) of house sparrows (Passer domesticus) in a metapopulation at Helgeland, Norway. Genomic (gDNA) and transcribed (cDNA) alleles of functional MHC class I and IIB loci, along with neutral noncoding microsatellite markers, were analyzed to obtain relevant estimates of genetic variation. We found lower allelic richness in microsatellites in the inbred population, but high genetic variation in MHC class I and IIB loci in both populations. This suggests that also the inbred population could be under balancing selection to maintain genetic variation for pathogen resistance. PMID:22393491

  6. Theory of population coupling and applications to describe high order correlations in large populations of interacting neurons

    NASA Astrophysics Data System (ADS)

    Huang, Haiping

    2017-03-01

    To understand the collective spiking activity in neuronal populations, it is essential to reveal basic circuit variables responsible for these emergent functional states. Here, I develop a mean field theory for the population coupling recently proposed in the studies of the visual cortex of mouse and monkey, relating the individual neuron activity to the population activity, and extend the original form to the second order, relating neuron-pair’s activity to the population activity, to explain the high order correlations observed in the neural data. I test the computational framework on the salamander retinal data and the cortical spiking data of behaving rats. For the retinal data, the original form of population coupling and its advanced form can explain a significant fraction of two-cell correlations and three-cell correlations, respectively. For the cortical data, the performance becomes much better, and the second order population coupling reveals non-local effects in local cortical circuits.

  7. The Use of Telemedicine and Mobile Technology to Promote Population Health and Population Management for Psychiatric Disorders.

    PubMed

    Turvey, Carolyn; Fortney, John

    2017-10-16

    This article discusses recent applications in telemedicine to promote the goals of population health and population management for people suffering psychiatric disorders. The use of telemedicine to promote collaborative care, self-monitoring and chronic disease management, and population screening has demonstrated broad applicability and effectiveness. Collaborative care using videoconferencing to facilitate mental health specialty consults has demonstrated effectiveness in the treatment of depression, PTSD, and also ADHD in pediatric populations. Mobile health is currently being harnessed to monitor patient symptom trajectories with the goal of using machine learning algorithms to predict illness relapse. Patient portals serve as a bridge between patients and providers. They provide an electronically secure shared space for providers and patients to collaborate and optimize care. To date, research has supported the effectiveness of telemedicine in promoting population health. Future endeavors should focus on developing the most effective clinical protocols for using these technologies to ensure long-term use and maximum effectiveness in reducing population burden of mental health.

  8. Genetic analysis of Mexican Criollo cattle populations.

    PubMed

    Ulloa-Arvizu, R; Gayosso-Vázquez, A; Ramos-Kuri, M; Estrada, F J; Montaño, M; Alonso, R A

    2008-10-01

    The objective of this study was to evaluate the genetic structure of Mexican Criollo cattle populations using microsatellite genetic markers. DNA samples were collected from 168 animals from four Mexican Criollo cattle populations, geographically isolated in remote areas of Sierra Madre Occidental (West Highlands). Also were included samples from two breeds with Iberian origin: the fighting bull (n = 24) and the milking central American Criollo (n = 24) and one Asiatic breed: Guzerat (n = 32). Genetic analysis consisted of the estimation of the genetic diversity in each population by the allele number and the average expected heterozygosity found in nine microsatellite loci. Furthermore, genetic relationships among the populations were defined by their genetic distances. Our data shows that Mexican cattle populations have a relatively high level of genetic diversity based either on the mean number of alleles (10.2-13.6) and on the expected heterozygosity (0.71-0.85). The degree of observed homozygosity within the Criollo populations was remarkable and probably caused by inbreeding (reduced effective population size) possibly due to reproductive structure within populations. Our data shows that considerable genetic differentiation has been occurred among the Criollo cattle populations in different regions of Mexico.

  9. Population growth and economic growth.

    PubMed

    Narayana, D L

    1984-01-01

    This discussion of the issues relating to the problem posed by population explosion in the developing countries and economic growth in the contemporary world covers the following: predictions of economic and social trends; the Malthusian theory of population; the classical or stationary theory of population; the medical triage model; ecological disaster; the Global 2000 study; the limits to growth; critiques of the Limits to Growth model; nonrenewable resources; food and agriculture; population explosion and stabilization; space and ocean colonization; and the limits perspective. The Limits to Growth model, a general equilibrium anti-growth model, is the gloomiest economic model ever constructed. None of the doomsday models, the Malthusian theory, the classical stationary state, the neo-Malthusian medical triage model, the Global 2000 study, are so far reaching in their consequences. The course of events that followed the publication of the "Limits to Growth" in 1972 in the form of 2 oil shocks, food shock, pollution shock, and price shock seemed to bear out formally the gloomy predictions of the thesis with a remarkable speed. The 12 years of economic experience and the knowledge of resource trends postulate that even if the economic pressures visualized by the model are at work they are neither far reaching nor so drastic. Appropriate action can solve them. There are several limitations to the Limits to Growth model. The central theme of the model, which is overshoot and collapse, is unlikely to be the course of events. The model is too aggregative to be realistic. It exaggerates the ecological disaster arising out of the exponential growth of population and industry. The gross underestimation of renewable resources is a basic flaw of the model. The most critical weakness of the model is its gross underestimation of the historical trend of technological progress and the technological possiblities within industry and agriculture. The model does correctly emphasize

  10. [Population change and social organization].

    PubMed

    Tu, J C

    1986-06-01

    This paper, published in Taiwan in June, 1986, studies the impact of demographic changes on social organization through stable population theory as applied to the USA. The stable population model indicates a constant age differential between death ratio and birth ratio maintained for a period of time in a given population. Since the 1950's, the population growth rate in the US has been 1.5%; social security tax revenue should increase 50% to maintain equilibrium. According to the US Census Bureau, in 1940, 11 people in 100 were age 65 or over; in 1980, 19 per 100; and 1 estimate places 32 in 100 over 65 in the year 2030. In 90 years the proportion of senior citizens will increase 3 times; social security taxes should consequently also increase 3 times. The stable population model would mean that social security tax should double its current rate to maintain equilibrium. However, based on the actual change in the population's age structure, social security tax should in fact increase at least 3 times. From 1940 to the present, social security tax revenue has already increased 3 times. Turning to education, in 1961, 4.39 million babies were born in the US. By the mid-1970's, births had slowed to an annual average of 3 million. The decrease in number of university students and posts available to Ph.Ds follows the birth rate change of 20 years earlier. Many graduate institutions will be influenced by this decrease in births. From another perspective, the birth rate decrease has also reduced the educational burden on society, and should provide more opportunities and resources. However, in the American educational system, research opportunities are determined by teaching positions which are dependent upon university enrollment figures. The US Census Bureau predicts that enrollment rates must double in order to compensate for the decrease in university age population.

  11. Stochastic population dynamics under resource constraints

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

    Gavane, Ajinkya S., E-mail: ajinkyagavane@gmail.com; Nigam, Rahul, E-mail: rahul.nigam@hyderabad.bits-pilani.ac.in

    This paper investigates the population growth of a certain species in which every generation reproduces thrice over a period of predefined time, under certain constraints of resources needed for survival of population. We study the survival period of a species by randomizing the reproduction probabilities within a window at same predefined ages and the resources are being produced by the working force of the population at a variable rate. This randomness in the reproduction rate makes the population growth stochastic in nature and one cannot predict the exact form of evolution. Hence we study the growth by running simulations formore » such a population and taking an ensemble averaged over 500 to 5000 such simulations as per the need. While the population reproduces in a stochastic manner, we have implemented a constraint on the amount of resources available for the population. This is important to make the simulations more realistic. The rate of resource production then is tuned to find the rate which suits the survival of the species. We also compute the mean life time of the species corresponding to different resource production rate. Study for these outcomes in the parameter space defined by the reproduction probabilities and rate of resource production is carried out.« less

  12. Population Structure in Nontypeable Haemophilus influenzae

    PubMed Central

    LaCross, Nathan C.; Marrs, Carl F.; Gilsdorf, Janet R.

    2013-01-01

    Nontypeable Haemophilus influenzae (NTHi) frequently colonize the human pharynx asymptomatically, and are an important cause of otitis media in children. Past studies have identified typeable H. influenzae as being clonal, but the population structure of NTHi has not been extensively characterized. The research presented here investigated the diversity and population structure in a well-characterized collection of NTHi isolated from the middle ears of children with otitis media or the pharynges of healthy children in three disparate geographic regions. Multilocus sequence typing identified 109 unique sequence types among 170 commensal and otitis media-associated NTHi isolates from Finland, Israel, and the US. The largest clonal complex contained only five sequence types, indicating a high level of genetic diversity. The eBURST v3, ClonalFrame 1.1, and structure 2.3.3 programs were used to further characterize diversity and population structure from the sequence typing data. Little clustering was apparent by either disease state (otitis media or commensalism) or geography in the ClonalFrame phylogeny. Population structure was clearly evident, with support for eight populations when all 170 isolates were analyzed. Interestingly, one population contained only commensal isolates, while two others consisted solely of otitis media isolates, suggesting associations between population structure and disease. PMID:23266487

  13. Population, Education, and Children's Futures. Fastback 150.

    ERIC Educational Resources Information Center

    Bjork, Robert M.; Fraser, Stewart E.

    This monograph discusses world population problems, examines the underlying concepts and issues in population education, and looks at the future. The monograph begins by describing an attempt at population education in a village of India. Eight guiding concepts that are considered to be essential for population educators are then discussed. These…

  14. Warfarin Pharmacogenomics in Diverse Populations.

    PubMed

    Kaye, Justin B; Schultz, Lauren E; Steiner, Heidi E; Kittles, Rick A; Cavallari, Larisa H; Karnes, Jason H

    2017-09-01

    Genotype-guided warfarin dosing algorithms are a rational approach to optimize warfarin dosing and potentially reduce adverse drug events. Diverse populations, such as African Americans and Latinos, have greater variability in warfarin dose requirements and are at greater risk for experiencing warfarin-related adverse events compared with individuals of European ancestry. Although these data suggest that patients of diverse populations may benefit from improved warfarin dose estimation, the vast majority of literature on genotype-guided warfarin dosing, including data from prospective randomized trials, is in populations of European ancestry. Despite differing frequencies of variants by race/ethnicity, most evidence in diverse populations evaluates variants that are most common in populations of European ancestry. Algorithms that do not include variants important across race/ethnic groups are unlikely to benefit diverse populations. In some race/ethnic groups, development of race-specific or admixture-based algorithms may facilitate improved genotype-guided warfarin dosing algorithms above and beyond that seen in individuals of European ancestry. These observations should be considered in the interpretation of literature evaluating the clinical utility of genotype-guided warfarin dosing. Careful consideration of race/ethnicity and additional evidence focused on improving warfarin dosing algorithms across race/ethnic groups will be necessary for successful clinical implementation of warfarin pharmacogenomics. The evidence for warfarin pharmacogenomics has a broad significance for pharmacogenomic testing, emphasizing the consideration of race/ethnicity in discovery of gene-drug pairs and development of clinical recommendations for pharmacogenetic testing. © 2017 Pharmacotherapy Publications, Inc.

  15. Election '94: a population overview.

    PubMed

    Dixon, B

    1994-01-01

    President Bill Clinton has been more outspoken and active than previous presidents in negotiations leading to the 1994 International Conference on Population and Development. He has put population stabilization at the top of the overall foreign policy agenda, sending to Congress a bill designed to make sustainable development and population stabilization cornerstones of US foreign policy. Moreover, the administration's commitment to solving the population problem is reflected in each of the two budgets submitted to Congress with increased funds requested and received for international family planning and the UN Population Fund. The US now leads the search for new solutions to the problem of rapid population growth. The right-wing conservatism and ignorance of the Reagan-Bush years, however, threatens to return following the November 1994 national elections. Historically, the party which controls the White House loses Congressional seats during mid-term elections. If the Democrats lose up to fifteen seats, the shift will be an historical norm. A Democratic loss of 25 or more seats, however, may pose a serious problem for Clinton. Domestic and international family planning, sex education, health care, abortion, and environmental protection all hang in the balance. During this period of increased partisanship, 36 of the 44 Republicans in the Senate supported a Helms amendment to limit US participation in the Cairo conference. Republican control of the Senate would likely keep the US from carrying out the commitments made at the conference on family planning, women's health coverage, and environmental protection.

  16. Individual and Population-Level Impacts of an Emerging Poxvirus Disease in a Wild Population of Great Tits

    PubMed Central

    Lachish, Shelly; Bonsall, Michael B.; Lawson, Becki; Cunningham, Andrew A.; Sheldon, Ben C.

    2012-01-01

    Emerging infectious diseases of wildlife can have severe effects on host populations and constitute a pressing problem for biodiversity conservation. Paridae pox is an unusually severe form of avipoxvirus infection that has recently been identified as an emerging infectious disease particularly affecting an abundant songbird, the great tit (Parus major), in Great Britain. In this study, we study the invasion and establishment of Paridae pox in a long-term monitored population of wild great tits to (i) quantify the impact of this novel pathogen on host fitness and (ii) determine the potential threat it poses to population persistence. We show that Paridae pox significantly reduces the reproductive output of great tits by reducing the ability of parents to fledge young successfully and rear those young to independence. Our results also suggested that pathogen transmission from diseased parents to their offspring was possible, and that disease entails severe mortality costs for affected chicks. Application of multistate mark-recapture modelling showed that Paridae pox causes significant reductions to host survival, with particularly large effects observed for juvenile survival. Using an age-structured population model, we demonstrate that Paridae pox has the potential to reduce population growth rate, primarily through negative impacts on host survival rates. However, at currently observed prevalence, significant disease-induced population decline seems unlikely, although pox prevalence may be underestimated if capture probability of diseased individuals is low. Despite this, because pox-affected model populations exhibited lower average growth rates, this emerging infectious disease has the potential to reduce the resilience of populations to other environmental factors that reduce population size. PMID:23185263

  17. Estimates of shorebird populations in North America

    USGS Publications Warehouse

    Morrison, R.I.G.; Gill, Robert E.; Harrington, B.A.; Skagen, S.K.; Page, G.W.; Gratto-Trevor, C. L.; Haig, S.M.

    2001-01-01

    Estimates are presented for the population sizes of 53 species of Nearctic shorebirds occurring regularly in North America, plus four species that breed occasionally. Population estimates range from a few tens to several millions. Overall, population estimates most commonly fall in the range of hundreds of thousands, particularly the low hundreds of thousands; estimated population sizes for large shorebird species currently all fall below 500 000. Population size is inversely related to size (mass) of the species, with a statistically significant negative regression between log(population size) and log(mass). Two outlying groups are evident on the regression graph: one, with populations lower than predicted, includes species considered to be either “at risk” or particularly hard to count, and a second, with populations higher than predicted, includes two species that are hunted. Shorebird population sizes were derived from data obtained by a variety of methods from breeding, migration, and wintering areas, and formal assessments of accuracy of counts or estimates are rarely available. Accurate estimates exist only for a few species that have been the subject of detailed investigation, and the likely accuracy of most estimates is considered poor or low. Population estimates are an integral part of conservation plans being developed for shorebirds in the United States and Canada and may be used to identify areas of key international and regional importance.

  18. Anomalous Growth of Aging Populations

    NASA Astrophysics Data System (ADS)

    Grebenkov, Denis S.

    2016-04-01

    We consider a discrete-time population dynamics with age-dependent structure. At every time step, one of the alive individuals from the population is chosen randomly and removed with probability q_k depending on its age, whereas a new individual of age 1 is born with probability r. The model can also describe a single queue in which the service order is random while the service efficiency depends on a customer's "age" in the queue. We propose a mean field approximation to investigate the long-time asymptotic behavior of the mean population size. The age dependence is shown to lead to anomalous power-law growth of the population at the critical regime. The scaling exponent is determined by the asymptotic behavior of the probabilities q_k at large k. The mean field approximation is validated by Monte Carlo simulations.

  19. Discrimination of Picea chihuahuana Martinez populations on the basis of climatic, edaphic, dendrometric, genetic and population traits

    PubMed Central

    Dominguez-Guerrero, Iliana Karina; del Rocío Mariscal-Lucero, Samantha; Hernández-Díaz, José Ciro; Heinze, Berthold; Prieto-Ruiz, José Ángel

    2017-01-01

    Background Picea chihuahuana, which is endemic to Mexico, is currently listed as “Endangered” on the Red List. Chihuahua spruce is only found in the Sierra Madre Occidental (SMO), Mexico. About 42,600 individuals are distributed in forty populations. These populations are fragmented and can be classified into three geographically distinct clusters in the SMO. The total area covered by P. chihuahuana populations is less than 300 ha. A recent study suggested assisted migration as an alternative to the ex situ conservation of P. chihuahuana, taking into consideration the genetic structure and diversity of the populations and the predictions regarding the future climate of the habitat. However, detailed background information is required to enable development of plans for protecting and conserving species and for successful assisted migration. Thus, it is important to identify differences between populations in relation to environmental conditions. The genetic diversity of populations, which affect vigor, evolution and adaptability of the species, must also be considered. In this study, we examined 14 populations of P. chihuahuana, with the overall aim of discriminating the populations and form clusters of this species. Methods Each population was represented by one 50 × 50 m plot established in the center of its respective location. Climate, soil, dasometric, density variables and genetic and species diversities were assessed in these plots for further analyses. The putatively neutral and adaptive AFLP markers were used to calculate genetic diversity. Affinity Propagation (AP) clustering technique and k-means clustering algorithm were used to classify the populations in the optimal number of clusters. Later stepwise binomial logistic regression was applied to test for significant differences in variables of the southern and northern P. chihuahuana populations. Spearman’s correlation test was used to analyze the relationships among all variables studied

  20. Population stratification effect on cancer susceptibility in an admixed population from Brazilian Amazon.

    PubMed

    Vieira, Priscilla Cristina Moura; Burbano, Rommel Mario Rodríguez; Fernandes, Débora Christina Ricardo Oliveira; Montenegro, Raquel Carvalho; Dos Santos, Sidney Emanuel Batista; Sortica, Vinicius Albuquerque; Assumpção, Paulo Pimentel; Ribeiro-Dos-Santos, Ândrea Kely Campos; Carvalho, Antônio Alberto; Dos Santos, Ney Pereira Carneiro

    2015-04-01

    Many efforts have been made to identify candidate genes involved in cancer susceptibility. The present study aimed to investigate the association between Arg194Trp (XRCC1), Ala222Val (MTHFR) and Arg521Lys (EGFR) polymorphisms (SNPs) and their susceptibility to gastric and breast carcinoma cancer in patients from Brazilian Amazon, controlling population structure interference. The SNPs were genotyped by TaqMan® SNP Genotyping Assays. Ancestry was estimated by analysis of a panel with 48 ancestry informative markers. Logistic regression analysis showed an inverse association with a 10% increase in African and European ancestry and cancer risk (odds ratio (OR)=1.919 and 0.676, respectively). In a preliminary Chi-square analysis a positive association between Arg521Lys (EGFR) polymorphism and carcinoma susceptibility was found (p=0.037); however, when two different methodologies to control population structure bias were utilized, this association was lost (p=0.064 and p=0.256). Genetic ancestry influence gastric and breast cancer risk and highlight the importance of population structure inference in association studies in highly admixed populations, such as those from Brazilian Amazon. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  1. Possible ancestral structure in human populations.

    PubMed

    Plagnol, Vincent; Wall, Jeffrey D

    2006-07-01

    Determining the evolutionary relationships between fossil hominid groups such as Neanderthals and modern humans has been a question of enduring interest in human evolutionary genetics. Here we present a new method for addressing whether archaic human groups contributed to the modern gene pool (called ancient admixture), using the patterns of variation in contemporary human populations. Our method improves on previous work by explicitly accounting for recent population history before performing the analyses. Using sequence data from the Environmental Genome Project, we find strong evidence for ancient admixture in both a European and a West African population (p approximately 10(-7)), with contributions to the modern gene pool of at least 5%. While Neanderthals form an obvious archaic source population candidate in Europe, there is not yet a clear source population candidate in West Africa.

  2. Population and labour force projections for 27 European countries, 2002-052: impact of international migration on population ageing: Projections de population et de population active pour 27 pays européens 2002-052: impact de la migration internationale sur le vieillissement de la population.

    PubMed

    Bijak, Jakub; Kupiszewska, Dorota; Kupiszewski, Marek; Saczuk, Katarzyna; Kicinger, Anna

    2007-03-01

    Population and labour force projections are made for 27 selected European countries for 2002-052, focussing on the impact of international migration on population and labour force dynamics. Starting from single scenarios for fertility, mortality and economic activity, three sets of assumptions are explored regarding migration flows, taking into account probable policy developments in Europe following the enlargement of the EU. In addition to age structures, various support ratio indicators are analysed. The results indicate that plausible immigration cannot offset the negative effects of population and labour force ageing.

  3. Dynamics of newly established elk populations

    USGS Publications Warehouse

    Sargeant, G.A.; Oehler, M.W.

    2007-01-01

    The dynamics of newly established elk (Cervus elaphus) populations can provide insights about maximum sustainable rates of reproduction, survival, and increase. However, data used to estimate rates of increase typically have been limited to counts and rarely have included complementary estimates of vital rates. Complexities of population dynamics cannot be understood without considering population processes as well as population states. We estimated pregnancy rates, survival rates, age ratios, and sex ratios for reintroduced elk at Theodore Roosevelt National Park, North Dakota, USA; combined vital rates in a population projection model; and compared model projections with observed elk numbers and population ratios. Pregnancy rates in January (early in the second trimester of pregnancy) averaged 54.1% (SE = 5.4%) for subadults and 91.0% (SE = 1.7%) for adults, and 91.6% of pregnancies resulted in recruitment at 8 months. Annual survival rates of adult females averaged 0.96 (95% CI = 0.94-0.98) with hunting included and 0.99 (95% CI = 0.97-0.99) with hunting excluded from calculations. Our fitted model explained 99.8% of past variation in population estimates and represents a useful new tool for short-term management planning. Although we found no evidence of temporal variation in vital rates, variation in population composition caused substantial variation in projected rates of increase (??=1.20-1.36). Restoring documented hunter harvests and removals of elk by the National Park Service led to a potential rate of ?? = 1.26. Greater rates of increase substantiated elsewhere were within the expected range of chance variation, given our model and estimates of vital rates. Rates of increase realized by small elk populations are too variable to support inferences about habitat quality or density dependence.

  4. Our Population Predicament: A New Look.

    ERIC Educational Resources Information Center

    van der Tak, Jean, Ed.; And Others

    1979-01-01

    This Bulletin updates the story of world population presented in 1971, "Man's Population Predicament." Estimated at half a billion in 1650, world population reached 2 billion in 1930, 4 billion in 1975, and is projected to be about 6 billion in 2000. Most of today's rapid growth is occurring among people living in less developed…

  5. Leading edge gypsy moth population dynamics

    Treesearch

    M. R. Carter; F. W. Ravlin; M. L. McManus

    1991-01-01

    Leading edge gypsy moth populations have been the focus of several intervention programs (MDIPM, AIPM). Knowledge of gypsy moth population dynamics in leading edge area is crucial for effective management. Populations in these areas tend to reach outbreak levels (noticeable defoliation) within three to four years after egg masses are first detected. Pheromone traps...

  6. Discontinuous Galerkin finite element method for solving population density functions of cortical pyramidal and thalamic neuronal populations.

    PubMed

    Huang, Chih-Hsu; Lin, Chou-Ching K; Ju, Ming-Shaung

    2015-02-01

    Compared with the Monte Carlo method, the population density method is efficient for modeling collective dynamics of neuronal populations in human brain. In this method, a population density function describes the probabilistic distribution of states of all neurons in the population and it is governed by a hyperbolic partial differential equation. In the past, the problem was mainly solved by using the finite difference method. In a previous study, a continuous Galerkin finite element method was found better than the finite difference method for solving the hyperbolic partial differential equation; however, the population density function often has discontinuity and both methods suffer from a numerical stability problem. The goal of this study is to improve the numerical stability of the solution using discontinuous Galerkin finite element method. To test the performance of the new approach, interaction of a population of cortical pyramidal neurons and a population of thalamic neurons was simulated. The numerical results showed good agreement between results of discontinuous Galerkin finite element and Monte Carlo methods. The convergence and accuracy of the solutions are excellent. The numerical stability problem could be resolved using the discontinuous Galerkin finite element method which has total-variation-diminishing property. The efficient approach will be employed to simulate the electroencephalogram or dynamics of thalamocortical network which involves three populations, namely, thalamic reticular neurons, thalamocortical neurons and cortical pyramidal neurons. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Population and women in development: gender issues in the context of population and development.

    PubMed

    Eshete, A

    1992-12-01

    "The objective of this paper is to examine women's productive and reproductive roles and their intricate linkages and the interplay with the demographic variables of population and development. Although these interactions...are not yet fully understood, attempts will be made utilizing available data and literature to make an analysis of the linkages and interplays that exist between population variables with factors associated with the role, status and participation of women in the social and economic lives of African societies.... The paper will analyze the linkages and integrate the implications for population policies and programmes towards the enhancement of women's role and status and their participation in the development process." excerpt

  8. Comparing models of Red Knot population dynamics

    USGS Publications Warehouse

    McGowan, Conor P.

    2015-01-01

    Predictive population modeling contributes to our basic scientific understanding of population dynamics, but can also inform management decisions by evaluating alternative actions in virtual environments. Quantitative models mathematically reflect scientific hypotheses about how a system functions. In Delaware Bay, mid-Atlantic Coast, USA, to more effectively manage horseshoe crab (Limulus polyphemus) harvests and protect Red Knot (Calidris canutus rufa) populations, models are used to compare harvest actions and predict the impacts on crab and knot populations. Management has been chiefly driven by the core hypothesis that horseshoe crab egg abundance governs the survival and reproduction of migrating Red Knots that stopover in the Bay during spring migration. However, recently, hypotheses proposing that knot dynamics are governed by cyclical lemming dynamics garnered some support in data analyses. In this paper, I present alternative models of Red Knot population dynamics to reflect alternative hypotheses. Using 2 models with different lemming population cycle lengths and 2 models with different horseshoe crab effects, I project the knot population into the future under environmental stochasticity and parametric uncertainty with each model. I then compare each model's predictions to 10 yr of population monitoring from Delaware Bay. Using Bayes' theorem and model weight updating, models can accrue weight or support for one or another hypothesis of population dynamics. With 4 models of Red Knot population dynamics and only 10 yr of data, no hypothesis clearly predicted population count data better than another. The collapsed lemming cycle model performed best, accruing ~35% of the model weight, followed closely by the horseshoe crab egg abundance model, which accrued ~30% of the weight. The models that predicted no decline or stable populations (i.e. the 4-yr lemming cycle model and the weak horseshoe crab effect model) were the most weakly supported.

  9. Iraqi Population Displacement Analysis

    DTIC Science & Technology

    2016-11-01

    CENTER FOR ARMY ANALYSIS 6001 GOETHALS ROAD FORT BELVOIR, VA 22060-5230 CAA-2015098 IRAQI POPULATION DISPLACEMENT ANALYSIS NOVEMBER 2016...CONTRACT NUMBER Iraqi Population Displacement Analysis PDMC 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER Ms...NOTES 14. ABSTRACT The purpose of this study was to inform CJ34 Civil Military Operations decisions on placement of internally displaced person (IDP

  10. Transgender Population Size in the United States: a Meta-Regression of Population-Based Probability Samples

    PubMed Central

    Sevelius, Jae M.

    2017-01-01

    Background. Transgender individuals have a gender identity that differs from the sex they were assigned at birth. The population size of transgender individuals in the United States is not well-known, in part because official records, including the US Census, do not include data on gender identity. Population surveys today more often collect transgender-inclusive gender-identity data, and secular trends in culture and the media have created a somewhat more favorable environment for transgender people. Objectives. To estimate the current population size of transgender individuals in the United States and evaluate any trend over time. Search methods. In June and July 2016, we searched PubMed, Cumulative Index to Nursing and Allied Health Literature, and Web of Science for national surveys, as well as “gray” literature, through an Internet search. We limited the search to 2006 through 2016. Selection criteria. We selected population-based surveys that used probability sampling and included self-reported transgender-identity data. Data collection and analysis. We used random-effects meta-analysis to pool eligible surveys and used meta-regression to address our hypothesis that the transgender population size estimate would increase over time. We used subsample and leave-one-out analysis to assess for bias. Main results. Our meta-regression model, based on 12 surveys covering 2007 to 2015, explained 62.5% of model heterogeneity, with a significant effect for each unit increase in survey year (F = 17.122; df = 1,10; b = 0.026%; P = .002). Extrapolating these results to 2016 suggested a current US population size of 390 adults per 100 000, or almost 1 million adults nationally. This estimate may be more indicative for younger adults, who represented more than 50% of the respondents in our analysis. Authors’ conclusions. Future national surveys are likely to observe higher numbers of transgender people. The large variety in questions used to ask

  11. [Natural forming causes of China population distribution].

    PubMed

    Fang, Yu; Ouyang, Zhi-Yun; Zheng, Hua; Xiao, Yi; Niu, Jun-Feng; Chen, Sheng-Bin; Lu, Fei

    2012-12-01

    The diverse natural environment in China causes the spatial heterogeneity of China population distribution. It is essential to understand the interrelations between the population distribution pattern and natural environment to enhance the understanding of the man-land relationship and the realization of the sustainable management for the population, resources, and environment. This paper analyzed the China population distribution by adopting the index of population density (PD) in combining with spatial statistic method and Lorenz curve, and discussed the effects of the natural factors on the population distribution and the interrelations between the population distribution and 16 indices including average annual precipitation (AAP), average annual temperature (AAT), average annual sunshine duration (AASD), precipitation variation (PV), temperature variation (TV), sunshine duration variation (SDV), relative humidity (RH), aridity index (AI), warmth index ( WI), > or = 5 degrees C annual accumulated temperature (AACT), average elevation (AE), relative height difference (RHD), surface roughness (SR), water system density (WSD), net primary productivity (NPP), and shortest distance to seashore (SDTS). There existed an obvious aggregation phenomenon in the population distribution in China. The PD was high in east China, medium in central China, and low in west China, presenting an obvious positive spatial association. The PD was significantly positively correlated with WSD, AAT, AAP, NPP, AACT, PV, RH, and WI, and significantly negatively correlated with RHD, AE, SDV, SR, and SDTS. The climate factors (AAT, WI, PV, and NPP), topography factors (SR and RHD), and water system factor (WSD) together determined the basic pattern of the population distribution in China. It was suggested that the monitoring of the eco-environment in the east China of high population density should be strengthened to avoid the eco-environmental degradation due to the expanding population, and

  12. Fishing amplifies forage fish population collapses.

    PubMed

    Essington, Timothy E; Moriarty, Pamela E; Froehlich, Halley E; Hodgson, Emma E; Koehn, Laura E; Oken, Kiva L; Siple, Margaret C; Stawitz, Christine C

    2015-05-26

    Forage fish support the largest fisheries in the world but also play key roles in marine food webs by transferring energy from plankton to upper trophic-level predators, such as large fish, seabirds, and marine mammals. Fishing can, thereby, have far reaching consequences on marine food webs unless safeguards are in place to avoid depleting forage fish to dangerously low levels, where dependent predators are most vulnerable. However, disentangling the contributions of fishing vs. natural processes on population dynamics has been difficult because of the sensitivity of these stocks to environmental conditions. Here, we overcome this difficulty by collating population time series for forage fish populations that account for nearly two-thirds of global catch of forage fish to identify the fingerprint of fisheries on their population dynamics. Forage fish population collapses shared a set of common and unique characteristics: high fishing pressure for several years before collapse, a sharp drop in natural population productivity, and a lagged response to reduce fishing pressure. Lagged response to natural productivity declines can sharply amplify the magnitude of naturally occurring population fluctuations. Finally, we show that the magnitude and frequency of collapses are greater than expected from natural productivity characteristics and therefore, likely attributed to fishing. The durations of collapses, however, were not different from those expected based on natural productivity shifts. A risk-based management scheme that reduces fishing when populations become scarce would protect forage fish and their predators from collapse with little effect on long-term average catches.

  13. Violence Reported by the Immigrant Population Is High as Compared with the Native Population in Southeast Spain

    ERIC Educational Resources Information Center

    Colorado-Yohar, S.; Tormo, M. J.; Salmeron, D.; Dios, S.; Ballesta, M.; Navarro, C.

    2012-01-01

    Immigrants constitute a population vulnerable to the problem of violence. This study sought to ascertain the prevalence of violence reported by the immigrant population in the Murcian Region of Spain and characterize the related factors, taking the country population as reference. A cross-sectional study was carried out based on a representative…

  14. Learning Experiences in Population Education. Population Education Programme Service, Volume 3. For the Non-Formal Education System.

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific, and Cultural Organization, Bangkok (Thailand). Regional Office for Education in Asia and the Pacific.

    One of the main products of the Regional Workshop for the Development of Packages of Adequate Learning Requirements in Population is this prototype package of curriculum materials in population education. The workshop notes that one of the shortcomings of country programs in population education is that the content integrated in school subjects is…

  15. Population and performance analyses of four major populations with Illumina's FGx Forensic Genomics System.

    PubMed

    Churchill, Jennifer D; Novroski, Nicole M M; King, Jonathan L; Seah, Lay Hong; Budowle, Bruce

    2017-09-01

    The MiSeq FGx Forensic Genomics System (Illumina) enables amplification and massively parallel sequencing of 59 STRs, 94 identity informative SNPs, 54 ancestry informative SNPs, and 24 phenotypic informative SNPs. Allele frequency and population statistics data were generated for the 172 SNP loci included in this panel on four major population groups (Chinese, African Americans, US Caucasians, and Southwest Hispanics). Single-locus and combined random match probability values were generated for the identity informative SNPs. The average combined STR and identity informative SNP random match probabilities (assuming independence) across all four populations were 1.75E-67 and 2.30E-71 with length-based and sequence-based STR alleles, respectively. Ancestry and phenotype predictions were obtained using the ForenSeq™ Universal Analysis System (UAS; Illumina) based on the ancestry informative and phenotype informative SNP profiles generated for each sample. Additionally, performance metrics, including profile completeness, read depth, relative locus performance, and allele coverage ratios, were evaluated and detailed for the 725 samples included in this study. While some genetic markers included in this panel performed notably better than others, performance across populations was generally consistent. The performance and population data included in this study support that accurate and reliable profiles were generated and provide valuable background information for laboratories considering internal validation studies and implementation. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Population genetic data of 38 insertion-deletion markers in six populations of the northern fringe of the Iberian Peninsula.

    PubMed

    Cardoso, Sergio; Sevillano, Rubén; Gamarra, David; Santurtún, Ana; Martínez-Jarreta, Begoña; de Pancorbo, Marian M

    2017-03-01

    Insertion-deletions have been reported very useful markers for forensic purposes. To further deepen in this matter, 38 non-coding bi-allelic autosomal indels were analyzed in 575 individuals representing six populations from the northern fringe of the Iberian Peninsula. Autochthonous populations from the Basque Country, northern Navarre, the Pas Valley in Cantabria and Aragon were analyzed, together with non-autochthonous populations from the Basque Country and northern Navarre. At the intra-population level, all loci analyzed were in Hardy-Weinberg equilibrium except for marker rs33917182 in autochthonous Basques. Linkage disequilibrium (LD) test did not reveal statistically significant allelic association between the different loci pairs in all six populations. Forensic parameters proved to be highly informative in the six populations analyzed, even if a scenario with population substructure and local inbreeding was considered for match probability calculations, and the potential of this indels set to be used in combination with other genetic markers is remarkable. As for inter-population analyses, in general terms the six populations showed low but statistically significant genetic distances. However, though this indels set efficiently differentiate between main ancestries, it does not allow an accurate separation at a local level and, for the time being, their combination with other informative markers is needed to maximize the power to accurately differentiate populations with close genetic ancestry. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  17. Mapping asthma-associated variants in admixed populations

    PubMed Central

    Mersha, Tesfaye B.

    2015-01-01

    Admixed populations arise when two or more previously isolated populations interbreed. Mapping asthma susceptibility loci in an admixed population using admixture mapping (AM) involves screening the genome of individuals of mixed ancestry for chromosomal regions that have a higher frequency of alleles from a parental population with higher asthma risk as compared with parental population with lower asthma risk. AM takes advantage of the admixture created in populations of mixed ancestry to identify genomic regions where an association exists between genetic ancestry and asthma (in contrast to between the genotype of the marker and asthma). The theory behind AM is that chromosomal segments of affected individuals contain a significantly higher-than-average proportion of alleles from the high-risk parental population and thus are more likely to harbor disease–associated loci. Criteria to evaluate the applicability of AM as a gene mapping approach include: (1) the prevalence of the disease differences in ancestral populations from which the admixed population was formed; (2) a measurable difference in disease-causing alleles between the parental populations; (3) reduced linkage disequilibrium (LD) between unlinked loci across chromosomes and strong LD between neighboring loci; (4) a set of markers with noticeable allele-frequency differences between parental populations that contributes to the admixed population (single nucleotide polymorphisms (SNPs) are the markers of choice because they are abundant, stable, relatively cheap to genotype, and informative with regard to the LD structure of chromosomal segments); and (5) there is an understanding of the extent of segmental chromosomal admixtures and their interactions with environmental factors. Although genome-wide association studies have contributed greatly to our understanding of the genetic components of asthma, the large and increasing degree of admixture in populations across the world create many challenges

  18. Population ageing and dental care.

    PubMed

    Harford, Jane

    2009-04-01

    Population ageing is a fact in both developed and developing countries. The concern about population ageing largely arises from the combination of a greater number of older people requiring greater amounts of healthcare services and pensions, and relatively fewer people working to pay for them. Oral health and dental care are important aspects of health and health care. Lower rates of edentulism and an ageing population mean that older people will feature more prominently in dental services. Traditionally, economic studies of ageing have focused on the fiscal implications of ageing, projecting the increased burden on health and welfare services that accompanies ageing. It assumed that ageing is the major driver of recent changes and those past trends will simply be amplified by faster population ageing in the future. Less work has been done to understand other past drivers of increased healthcare spending and their implications for the future. The conclusion of these reports is usually that population ageing is unaffordable with current policy settings. They have proposed policies to deal with population ageing which focused on increasing workforce participation and worker productivity to increase the tax base and reducing entitlements. However, the affordability question is as much political as a numerical. There are no clearly articulated criteria for affordability and little opportunity for public discourse about what citizens are willing to pay in taxes to support an ageing population. While the reports do not necessarily reflect public opinion, they will certainly shape it. Predicting the future for oral health is more fraught than for general health, as oral health is in the midst of an epidemiological transition from high rates of edentulism and tooth loss to low rates. Changes in the pattern of dental expenditure in the past do not mirror the experience of rapid increases in per capita expenditure on older age groups as regards general health. Dentistry

  19. Population education for social betterment.

    PubMed

    Mukhi, S

    1983-01-26

    In India primary education has increased 3 times in the last 30 years. Over this same period middle school education has increased 4 times, higher secondary education 5 times, and university level education over 6 times. The number of universities alone increased from 19 in 1950 to 118 by 1981. The inconsistencies brought about by rapid population growth may be judged by the fact that while the number of institutions and the enrollment of students has expanded beyond measure, the number of illiterate persons has risen from 386 million in 1971 to 446 million in 1981. Clearly, education is vital for human resource development. In political terms, human resource development prepares a population for adult participation in political processes. From social and cultural perspectives, the development of human resources helps people to lead fuller and richer lives. Population means people, and people need food, clothing, homes, education, transportation, health services, and jobs. As long as a country's resources can satisfy the essential needs of its population, there is no population problem. If the population grows faster than the rate at which the basic needs of each individual can be met, the buildup of such a situation produces a crisis of gigantic dimensions. To meet basic requirements, India needs to provide annually an additional 12 million tons of foodgrains, 188 million meters of cloth, 2.5 million houses, along with schools, teachers, and jobs over and above what is currently available. Another need is for fresh air, pure water, and space to live in. The question is how is this need to be met when the earth is a finite sphere. What will happen when the world's 3.5 billion people double into a staggering 7 billion by the end of the 20th century. It is because of this concern for family well being and the betterment of human resources that the Family Planning Association of India has since 1969 undertaken innovative pilot programs in popultion education for the

  20. Fitness decline under osmotic stress in Caenorhabditis elegans populations subjected to spontaneous mutation accumulation at varying population sizes.

    PubMed

    Katju, Vaishali; Packard, Lucille B; Keightley, Peter D

    2018-04-01

    The consequences of mutations for population fitness depends on their individual selection coefficients and the effective population size. An earlier study of Caenorhabditis elegans spontaneous mutation accumulation lines evolved for 409 generations at three population sizes found that N e   = 1 populations declined significantly in fitness whereas the fitness of larger populations (N e   = 5, 50) was indistinguishable from the ancestral control under benign conditions. To test if larger MA populations harbor a load of cryptic deleterious mutations that are obscured under benign laboratory conditions, we measured fitness under osmotic stress via exposure to hypersaline conditions. The fitness of N e   = 1 lines exhibited a further decline under osmotic stress compared to benign conditions. However, the fitness of larger populations remained indistinguishable from that of the ancestral control. The average effects of deleterious mutations in N e   = 1 lines were estimated to be 22% for productivity and 14% for survivorship, exceeding values previously detected under benign conditions. Our results suggest that fitness decline is due to large effect mutations that are rapidly removed via selection even in small populations, with implications for conservation practices. Genetic stochasticity may not be as potent and immediate a threat to the persistence of small populations as other demographic and environmental stochastic factors. © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

  1. Impact of in-Sewer Degradation of Pharmaceutical and Personal Care Products (PPCPs) Population Markers on a Population Model.

    PubMed

    O'Brien, Jake William; Banks, Andrew Phillip William; Novic, Andrew Joseph; Mueller, Jochen F; Jiang, Guangming; Ort, Christoph; Eaglesham, Geoff; Yuan, Zhiguo; Thai, Phong K

    2017-04-04

    A key uncertainty of wastewater-based epidemiology is the size of the population which contributed to a given wastewater sample. We previously developed and validated a Bayesian inference model to estimate population size based on 14 population markers which: (1) are easily measured and (2) have mass loads which correlate with population size. However, the potential uncertainty of the model prediction due to in-sewer degradation of these markers was not evaluated. In this study, we addressed this gap by testing their stability under sewer conditions and assessed whether degradation impacts the model estimates. Five markers, which formed the core of our model, were stable in the sewers while the others were not. Our evaluation showed that the presence of unstable population markers in the model did not decrease the precision of the population estimates providing that stable markers such as acesulfame remained in the model. However, to achieve the minimum uncertainty in population estimates, we propose that the core markers to be included in population models for other sites should meet two additional criteria: (3) negligible degradation in wastewater to ensure the stability of chemicals during collection; and (4) < 10% in-sewer degradation could occur during the mean residence time of the sewer network.

  2. Emergence of cytotoxic resistance in cancer cell populations: Single-cell mechanisms and population-level consequences

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

    Lorenzi, Tommaso; Chisholm, Rebecca H.; Lorz, Alexander

    We formulate an individual-based model and a population model of phenotypic evolution, under cytotoxic drugs, in a cancer cell population structured by the expression levels of survival-potential and proliferation-potential. We apply these models to a recently studied experimental system. Our results suggest that mechanisms based on fundamental laws of biology can reversibly push an actively-proliferating, and drug-sensitive, cell population to transition into a weakly-proliferative and drug-tolerant state, which will eventually facilitate the emergence of more potent, proliferating and drug-tolerant cells.

  3. Population Profile of the United States 1984-85.

    ERIC Educational Resources Information Center

    Current Population Reports, 1987

    1987-01-01

    This population profile summarizes the wide range of demographic and socio-economic data collected from the Current Population Survey during 1984 and 1985. The report contains information on the following areas: National Population Trends; National Population Projections; Fertility; State Population Trends; The Metropolitan/Nonmetropolitan…

  4. Population genetics, community of parasites, and resistance to rodenticides in an urban brown rat (Rattus norvegicus) population

    PubMed Central

    Gasqui, Patrick; Cosson, Jean-François; Benoît, Etienne; Lattard, Virginie; Crespin, Laurent; Lorvelec, Olivier; Pisanu, Benoît; Teynié, Alexandre; Vayssier-Taussat, Muriel; Bonnet, Sarah; Marianneau, Philippe; Lacôte, Sandra; Bourhy, Pascale; Berny, Philippe; Pavio, Nicole; Le Poder, Sophie; Gilot-Fromont, Emmanuelle; Jourdain, Elsa; Hammed, Abdessalem; Fourel, Isabelle; Chikh, Farid; Vourc’h, Gwenaël

    2017-01-01

    Brown rats are one of the most widespread urban species worldwide. Despite the nuisances they induce and their potential role as a zoonotic reservoir, knowledge on urban rat populations remains scarce. The main purpose of this study was to characterize an urban brown rat population from Chanteraines park (Hauts-de-Seine, France), with regards to haematology, population genetics, immunogenic diversity, resistance to anticoagulant rodenticides, and community of parasites. Haematological parameters were measured. Population genetics was investigated using 13 unlinked microsatellite loci. Immunogenic diversity was assessed for Mhc-Drb. Frequency of the Y139F mutation (conferring resistance to rodenticides) and two linked microsatellites were studied, concurrently with the presence of anticoagulant residues in the liver. Combination of microscopy and molecular methods were used to investigate the occurrence of 25 parasites. Statistical approaches were used to explore multiple parasite relationships and model parasite occurrence. Eighty-six rats were caught. The first haematological data for a wild urban R. norvegicus population was reported. Genetic results suggested high genetic diversity and connectivity between Chanteraines rats and surrounding population(s). We found a high prevalence (55.8%) of the mutation Y139F and presence of rodenticide residues in 47.7% of the sampled individuals. The parasite species richness was high (16). Seven potential zoonotic pathogens were identified, together with a surprisingly high diversity of Leptospira species (4). Chanteraines rat population is not closed, allowing gene flow and making eradication programs challenging, particularly because rodenticide resistance is highly prevalent. Parasitological results showed that co-infection is more a rule than an exception. Furthermore, the presence of several potential zoonotic pathogens, of which four Leptospira species, in this urban rat population raised its role in the maintenance

  5. Population genetics, community of parasites, and resistance to rodenticides in an urban brown rat (Rattus norvegicus) population.

    PubMed

    Desvars-Larrive, Amélie; Pascal, Michel; Gasqui, Patrick; Cosson, Jean-François; Benoît, Etienne; Lattard, Virginie; Crespin, Laurent; Lorvelec, Olivier; Pisanu, Benoît; Teynié, Alexandre; Vayssier-Taussat, Muriel; Bonnet, Sarah; Marianneau, Philippe; Lacôte, Sandra; Bourhy, Pascale; Berny, Philippe; Pavio, Nicole; Le Poder, Sophie; Gilot-Fromont, Emmanuelle; Jourdain, Elsa; Hammed, Abdessalem; Fourel, Isabelle; Chikh, Farid; Vourc'h, Gwenaël

    2017-01-01

    Brown rats are one of the most widespread urban species worldwide. Despite the nuisances they induce and their potential role as a zoonotic reservoir, knowledge on urban rat populations remains scarce. The main purpose of this study was to characterize an urban brown rat population from Chanteraines park (Hauts-de-Seine, France), with regards to haematology, population genetics, immunogenic diversity, resistance to anticoagulant rodenticides, and community of parasites. Haematological parameters were measured. Population genetics was investigated using 13 unlinked microsatellite loci. Immunogenic diversity was assessed for Mhc-Drb. Frequency of the Y139F mutation (conferring resistance to rodenticides) and two linked microsatellites were studied, concurrently with the presence of anticoagulant residues in the liver. Combination of microscopy and molecular methods were used to investigate the occurrence of 25 parasites. Statistical approaches were used to explore multiple parasite relationships and model parasite occurrence. Eighty-six rats were caught. The first haematological data for a wild urban R. norvegicus population was reported. Genetic results suggested high genetic diversity and connectivity between Chanteraines rats and surrounding population(s). We found a high prevalence (55.8%) of the mutation Y139F and presence of rodenticide residues in 47.7% of the sampled individuals. The parasite species richness was high (16). Seven potential zoonotic pathogens were identified, together with a surprisingly high diversity of Leptospira species (4). Chanteraines rat population is not closed, allowing gene flow and making eradication programs challenging, particularly because rodenticide resistance is highly prevalent. Parasitological results showed that co-infection is more a rule than an exception. Furthermore, the presence of several potential zoonotic pathogens, of which four Leptospira species, in this urban rat population raised its role in the maintenance

  6. Characteristics of the Low-Income Population, 1971. Current Population Reports: Consumer Income, Series P-60, Number 86.

    ERIC Educational Resources Information Center

    Shelburne, Elizabeth C.

    This report presents social and economic statistics for the population of the United States below the low-income level in 1971, based on the March 1972 Current Population Survey. Included are data on selected characteristics of the population below the low-income level in 1971, such as geographic distribution, race and ethnic origin, family…

  7. [Food and population: study of three countries].

    PubMed

    1988-12-01

    In 1985, despite a nearly 25% worldwide surplus of cereals, more than 700 million poor people had insufficient food and some 17 million children died of malnutrition or related causes. 16% of the developing world's population is undernourished. Rapid population growth is a major reason for the world's hunger. Large families exhaust the resources of many urban couples and rural couples with little land. Closely spaced pregnancies deplete the nutritional resources of the mother and lead to low birth weight babies and inadequate lactation. Population growth in already densely populated countries reduces the land available for each family, inevitably contributing to poverty and rural malnutrition. Unemployment and underemployment reach alarming proportions in the city, where the combination of high fertility rates and migration from the countryside have produced growth twice that of the world population as a whole. Few developing countries have been able to generate sufficient investment to create new jobs for all seeking them. Unstable governments attempt to pacify urban unrest by subsidizing food prices and concentrating social and economic investments in the cities, causing further deterioration in rural conditions. Today more than 60 countries have food deficits, although not all are suffering. India, Kenya, and Mexico are 3 countries that have had some success in balancing population growth and food production, but each still has undernourished population sectors because of economic policies that fail to provide sufficient help to their poor and because of implacable population growth. Ending malnutrition in the 3 countries will require reducing the cost of food for households and increasing their incomes, but both objectives are made more difficult by rapid population growth. As a result of the green revolution and other factors, food production in India has tripled since 1950, but population has almost doubled in the same years. With rapid population growth, per

  8. Demographic and genetic status of an isolated population of bog turtles (Glyptemys muhlenbergii): Implications for managing small populations of long-lived animals

    USGS Publications Warehouse

    Pittman, Shannon E.; King, T.L.; Faurby, S.; Dorcas, M.E.

    2011-01-01

    In this study, we sought to determine the population stability and genetic diversity of one isolated population of the federally-threatened bog turtle (Glyptemys muhlenbergii) in North Carolina. Using capture-recapture data, we estimated adult survival and population growth rate from 1992 to 2007. We found that the population decreased from an estimated 36 adult turtles in 1994 to approximately 11 adult turtles in 2007. We found a constant adult survival of 0. 893 (SE = 0. 018, 95% confidence interval, 0. 853-0. 924) between 1992 and 2007. Using 18 microsatellite markers, we compared the genetic status of this population with five other bog turtle populations. The target population displayed allelic richness (4. 8 ?? 0. 5) and observed heterozygosity (0. 619 ?? 0. 064) within the range of the other bog turtle populations. Coalescent analysis of population growth rate, effective population size, and timing of population structuring event also indicated the genetics of the target population were comparable to the other populations studied. Estimates of effective population size were a proportion of the census size in all populations except the target population, in which the effective population size was larger than the census size (30 turtles vs. 11 turtles). We attribute the high genetic diversity in the target population to the presence of multiple generations of old turtles. This study illustrates that the demographic status of populations of long-lived species may not be reflected genetically if a decline occurred recently. Consequently, the genetic integrity of populations of long-lived animals experiencing rapid demographic bottlenecks may be preserved through conservation efforts effective in addressing demographic problems. ?? 2011 Springer Science+Business Media B.V.

  9. 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.

  10. Genetic variation and co-variation for fitness between intra-population and inter-population backgrounds in the red flour beetle, Tribolium castaneum

    PubMed Central

    Drury, Douglas W.; Wade, Michael J.

    2010-01-01

    Hybrids from crosses between populations of the flour beetle, Tribolium castaneum, express varying degrees of inviability and morphological abnormalities. The proportion of allopatric population hybrids exhibiting these negative hybrid phenotypes varies widely, from 3% to 100%, depending upon the pair of populations crossed. We crossed three populations and measured two fitness components, fertility and adult offspring numbers from successful crosses, to determine how genes segregating within populations interact in inter-population hybrids to cause the negative phenotypes. With data from crosses of 40 sires from each of three populations to groups of 5 dams from their own and two divergent populations, we estimated the genetic variance and covariance for breeding value of fitness between the intra- and inter-population backgrounds and the sire × dam-population interaction variance. The latter component of the variance in breeding values estimates the change in genic effects between backgrounds owing to epistasis. Interacting genes with a positive effect, prior to fixation, in the sympatric background but a negative effect in the hybrid background cause reproductive incompatibility in the Dobzhansky-Muller speciation model. Thus, the sire × dam-population interaction provides a way to measure the progress toward speciation of genetically differentiating populations on a trait by trait basis using inter-population hybrids. PMID:21044199

  11. [To educate and to inform the population about population].

    PubMed

    Levy, M L

    1993-03-01

    Each society has multiple institutions that inform members about themselves and their world. The quality of the information received depends on the balance between the political, religious, intellectual, educational, and media institutions that supply information. Population questions are almost always absent from public education programs, because they deal with themes traditionally reserved for family and religious education. But the contemporary world has changed so much that families and the clerical world are no longer necessarily the best sources of instruction. The ignorance and passivity of many families leave a void that is difficult to fill. The difficulty arises because the need is to assist families in filling their role, and not to substitute for them. Educators, development technicians, psychologists, physicians, and sociologists should not be allowed to monopolize the task of educating children in areas related to population, and morality any more than priests should. The central discipline for questions of population is demography. The use of figures and quantitative categories such as age cohorts gives a "scientific" air to demographic discourse which masks the arbitrariness of many terms. At what age, for example, does one became single, or when does one cease to be an orphan? Explaining the European term "household" to Africans, or the African term "concession" to Europeans, illustrates the semantic problems impeding, understanding and communication. The diffusion of demographic information, like that of all numeric information, assumes that the complexity of data gathering and the conventions of calculation are understood. The risk of error and misunderstanding is greater in population than, for example, for the economy, because of the simple and universal nature of demographic subjects: birth, death, illness. Good understanding of demographic information should lead to a deeper understanding of apparently evident notions such as age, duration

  12. Does colour polymorphism enhance survival of prey populations?

    PubMed Central

    Wennersten, Lena; Forsman, Anders

    2009-01-01

    That colour polymorphism may protect prey populations from predation is an old but rarely tested hypothesis. We examine whether colour polymorphic populations of prey exposed to avian predators in an ecologically valid visual context were exposed to increased extinction risk compared with monomorphic populations. We made 2976 artificial pastry prey, resembling Lepidoptera larvae, in four different colours and presented them in 124 monomorphic and 124 tetramorphic populations on tree trunks and branches such that they would be exposed to predation by free-living birds, and monitored their ‘survival’. Among monomorphic populations, there was a significant effect of prey coloration on survival, confirming that coloration influenced susceptibility to visually oriented predators. Survival of polymorphic populations was inferior to that of monomorphic green populations, but did not differ significantly from monomorphic brown, yellow or red populations. Differences in survival within polymorphic populations paralleled those seen among monomorphic populations; the red morph most frequently went extinct first and the green morph most frequently survived the longest. Our findings do not support the traditional protective polymorphism hypothesis and are in conflict with those of earlier studies. As a possible explanation to our findings, we offer a competing ‘giveaway cue’ hypothesis: that polymorphic populations may include one morph that attracts the attention of predators and that polymorphic populations therefore may suffer increased predation compared with some monomorphic populations. PMID:19324729

  13. Different level of population differentiation among human genes.

    PubMed

    Wu, Dong-Dong; Zhang, Ya-Ping

    2011-01-14

    During the colonization of the world, after dispersal out of African, modern humans encountered changeable environments and substantial phenotypic variations that involve diverse behaviors, lifestyles and cultures, were generated among the different modern human populations. Here, we study the level of population differentiation among different populations of human genes. Intriguingly, genes involved in osteoblast development were identified as being enriched with higher FST SNPs, a result consistent with the proposed role of the skeletal system in accounting for variation among human populations. Genes involved in the development of hair follicles, where hair is produced, were also found to have higher levels of population differentiation, consistent with hair morphology being a distinctive trait among human populations. Other genes that showed higher levels of population differentiation include those involved in pigmentation, spermatid, nervous system and organ development, and some metabolic pathways, but few involved with the immune system. Disease-related genes demonstrate excessive SNPs with lower levels of population differentiation, probably due to purifying selection. Surprisingly, we find that Mendelian-disease genes appear to have a significant excessive of SNPs with high levels of population differentiation, possibly because the incidence and susceptibility of these diseases show differences among populations. As expected, microRNA regulated genes show lower levels of population differentiation due to purifying selection. Our analysis demonstrates different level of population differentiation among human populations for different gene groups.

  14. Amerciamysis bahia Stochastic Matrix Population Model for Laboratory Populations

    EPA Science Inventory

    The population model described here is a stochastic, density-independent matrix model for integrating the effects of toxicants on survival and reproduction of the marine invertebrate, Americamysis bahia. The model was constructed using Microsoft® Excel 2003. The focus of the mode...

  15. Population estimates for the Toiyabe population of the Columbia spotted frog (Rana luteiventris), 2004–10

    USGS Publications Warehouse

    Adams, Michael J.; Mellison, Chad; Galvan, Stephanie K.

    2013-01-01

    The Toiyabe population of Columbia spotted frogs (Rana luteiventris, hereafter "Toiyabe frogs") is a geographically isolated population located in central Nevada (fig. 1). The Toiyabe population is part of the Great Basin Distinct Population Segment of Columbia spotted frogs, and is a candidate for listing under the Endangered Species Act (U.S. Fish and Wildlife Service, 2011). The cluster of breeding sites in central Nevada represents the southernmost extremity of the Columbia spotted frogs' known range (Funk and others, 2008). Toiyabe frogs are known to occur in seven drainages in Nye County, Nevada: Reese River, Cow Canyon Creek, Ledbetter Canyon Creek, Cloverdale Creek, Stewart Creek, Illinois Creek, and Indian Valley Creek. Most of the Toiyabe frog population resides in the Reese River, Indian Valley Creek, and Cloverdale Creek drainages (fig. 1; Nevada Department of Wildlife, 2003). Approximately 90 percent of the Toiyabe frogs' habitat is on public land. Most of the public land habitat (95 percent) is managed by the U.S. Forest Service (USFS), while the Bureau of Land Management (BLM) manages the remainder. Additional Toiyabe frog habitat is under Yomba Shoshone Tribal management and in private ownership (Nevada Department of Wildlife, 2003). The BLM, USFS, Nevada Department of Wildlife (NDOW), Nevada Natural Heritage Program (NNHP), Nye County, and U.S Fish and Wildlife Service (USFWS) have monitored the Toiyabe population since 2004 using mark and recapture surveys (Nevada Department of Wildlife, 2004). The USFWS contracted with the U.S. Geological Survey (USGS) to produce population estimates using these data.

  16. Reproduction, abundance, and population growth for a fisher (Pekania pennanti) population in the Sierra National Forest, California

    Treesearch

    Rick A. Sweitzer; Viorel D. Popescu; Reginald H. Barrett; Kathryn L. Purcell; Craig M. Thompson

    2015-01-01

    In the west coast region of the United States, fishers (Pekania pennanti) exist in 2 remnant populations—1 in northern California and 1 in the southern Sierra Nevada, California—and 3 reintroduced populations (western Washington, southern Oregon, and northeastern California). The West Coast Distinct Population Segment of fishers encompassing all of...

  17. Topological Signatures for Population Admixture

    USDA-ARS?s Scientific Manuscript database

    Topological Signatures for Population AdmixtureDeniz Yorukoglu1, Filippo Utro1, David Kuhn2, Saugata Basu3 and Laxmi Parida1* Abstract Background: As populations with multi-linear transmission (i.e., mixing of genetic material from two parents, say) evolve over generations, the genetic transmission...

  18. Learning Disabilities Research: Defining Populations.

    ERIC Educational Resources Information Center

    Lovitt, Thomas C.; Jenkins, Joseph R.

    1979-01-01

    The article emphasizes the need for a uniform format for defining the populations selected for research, particularly with learning disabled individuals. The population descriptions from three studies dealing with some aspect of reading are presented and scrutinized in terms of the four categories. (Author/DLS)

  19. Use of driving-impairing medicines by a Spanish population: a population-based registry study

    PubMed Central

    Gutierrez-Abejón, Eduardo; Herrera-Gómez, Francisco; Criado-Espegel, Paloma

    2017-01-01

    Objective To assess the use of driving-impairing medicines (DIM) in the general population with special reference to length of use and concomitant use. Design Population-based registry study. Setting The year 2015 granted medicines consumption data recorded in the Castile and León (Spain) medicine dispensation registry was consulted. Participants Medicines and DIM consumers from a Spanish population (Castile and León: 2.4 million inhabitants). Exposure Medicines and DIM consumption. Patterns of use by age and gender based on the length of use (acute: 1–7 days, subacute: 8–29 days and chronic use: ≥30 days) were of interest. Estimations regarding the distribution of licensed drivers by age and gender were employed to determine the patterns of use of DIM. Results DIM were consumed by 34.4% (95% CI 34.3% to 34.5%) of the general population in 2015, more commonly with regularity (chronic use: 22.5% vs acute use: 5.3%) and more frequently by the elderly. On average, 2.3 DIM per person were dispensed, particularly to chronic users (2.8 DIM per person). Age and gender distribution differences were observed between the Castile and León medicine dispensation registry data and the drivers’ license census data. Of all DIM dispensed, 83.8% were in the Anatomical Therapeutic Chemical code group nervous system medicines (N), which were prescribed to 29.2% of the population. Conclusions The use of DIM was frequent in the general population. Chronic use was common, but acute and subacute use should also be considered. This finding highlights the need to make patients, health professionals, health providers, medicine regulatory agencies and policy-makers at large aware of the role DIM play in traffic safety. PMID:29170289

  20. The outlook for population growth.

    PubMed

    Lee, Ronald

    2011-07-29

    Projections of population size, growth rates, and age distribution, although extending to distant horizons, shape policies today for the economy, environment, and government programs such as public pensions and health care. The projections can lead to costly policy adjustments, which in turn can cause political and economic turmoil. The United Nations projects global population to grow from about 7 billion today to 9.3 billion in 2050 and 10.1 billion in 2100, while the Old Age Dependency Ratio doubles by 2050 and triples by 2100. How are such population projections made, and how certain can we be about the trends they foresee?

  1. Political economy of population growth.

    PubMed

    Mehta, S; Mehta, H S

    1987-01-01

    Tracing the origin of political economy as a class-science, this paper focuses on the political economy of population growth. Exposing the limitations of Malthusian ideas and their invalidity even for the capitalist economies, it discusses the subsequent revival of the Malthusian model during the period of de-colonization and the misinterpretation of the relationship between population growth and development in the developing and developed countries. Taking India, China, and Japan as some case studies, the paper examines the relationship between birth rate levels and some correlates. It elaborates on the Indian experience, emphasizing the association of population growth with poverty and unemployment and lays bare some of the hidden causes of these phenomena. The authors examine some interstate variations in India and identify constraints and prospects of the existing population policy. The paper proposes outlines of a democratic population policy as an integral part of India's development strategy which should recognize human beings not simply as consumers but also as producers of material values. It pleads for 1) restructuring of property relations; 2) bringing down the mortality rates and raising of the literacy levels, especially among females; and 3) improving nutritional levels, as prerequisites for bringing down birth rates.

  2. Population properties affect inbreeding avoidance in moose

    PubMed Central

    Herfindal, Ivar; Haanes, Hallvard; Røed, Knut H.; Solberg, Erling J.; Markussen, Stine S.; Heim, Morten; Sæther, Bernt-Erik

    2014-01-01

    Mechanisms reducing inbreeding are thought to have evolved owing to fitness costs of breeding with close relatives. In small and isolated populations, or populations with skewed age- or sex distributions, mate choice becomes limited, and inbreeding avoidance mechanisms ineffective. We used a unique individual-based dataset on moose from a small island in Norway to assess whether inbreeding avoidance was related to population structure and size, expecting inbreeding avoidance to be greater in years with larger populations and even adult sex ratios. The probability that a potential mating event was realized was negatively related to the inbreeding coefficient of the potential offspring, with a stronger relationship in years with a higher proportion or number of males in the population. Thus, adult sex ratio and population size affect the degree of inbreeding avoidance. Consequently, conservation managers should aim for sex ratios that facilitate inbreeding avoidance, especially in small and isolated populations. PMID:25540152

  3. Population properties affect inbreeding avoidance in moose.

    PubMed

    Herfindal, Ivar; Haanes, Hallvard; Røed, Knut H; Solberg, Erling J; Markussen, Stine S; Heim, Morten; Sæther, Bernt-Erik

    2014-12-01

    Mechanisms reducing inbreeding are thought to have evolved owing to fitness costs of breeding with close relatives. In small and isolated populations, or populations with skewed age- or sex distributions, mate choice becomes limited, and inbreeding avoidance mechanisms ineffective. We used a unique individual-based dataset on moose from a small island in Norway to assess whether inbreeding avoidance was related to population structure and size, expecting inbreeding avoidance to be greater in years with larger populations and even adult sex ratios. The probability that a potential mating event was realized was negatively related to the inbreeding coefficient of the potential offspring, with a stronger relationship in years with a higher proportion or number of males in the population. Thus, adult sex ratio and population size affect the degree of inbreeding avoidance. Consequently, conservation managers should aim for sex ratios that facilitate inbreeding avoidance, especially in small and isolated populations. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  4. Assessment of Population Status for a White Sucker (Catostomus commersoni) Population Exposed to Bleached Kraft Pulp Mill Effluent

    EPA Science Inventory

    A predictive model was developed to translate changes in the fecundity and the age structure of a breeding population of white sucker (Catostomus commersoni) collected in the field to alterations in population growth rate. Application of this density dependent population ...

  5. Novel synthetic Medea selfish genetic elements drive population replacement in Drosophila; a theoretical exploration of Medea-dependent population suppression.

    PubMed

    Akbari, Omar S; Chen, Chun-Hong; Marshall, John M; Huang, Haixia; Antoshechkin, Igor; Hay, Bruce A

    2014-12-19

    Insects act as vectors for diseases of plants, animals, and humans. Replacement of wild insect populations with genetically modified individuals unable to transmit disease provides a potentially self-perpetuating method of disease prevention. Population replacement requires a gene drive mechanism in order to spread linked genes mediating disease refractoriness through wild populations. We previously reported the creation of synthetic Medea selfish genetic elements able to drive population replacement in Drosophila. These elements use microRNA-mediated silencing of myd88, a maternally expressed gene required for embryonic dorso-ventral pattern formation, coupled with early zygotic expression of a rescuing transgene, to bring about gene drive. Medea elements that work through additional mechanisms are needed in order to be able to carry out cycles of population replacement and/or remove existing transgenes from the population, using second-generation elements that spread while driving first-generation elements out of the population. Here we report the synthesis and population genetic behavior of two new synthetic Medea elements that drive population replacement through manipulation of signaling pathways involved in cellular blastoderm formation or Notch signaling, demonstrating that in Drosophila Medea elements can be generated through manipulation of diverse signaling pathways. We also describe the mRNA and small RNA changes in ovaries and early embryos associated from Medea-bearing females. Finally, we use modeling to illustrate how Medea elements carrying genes that result in diapause-dependent female lethality could be used to bring about population suppression.

  6. Profile: the Philippine Population Information Network.

    PubMed

    1991-06-01

    The profile of Philippine Population Information Network (POPIN) is described in this article as having changed management structure from the Population Center Foundation to the Government's Population Commission, Information Management and Research Division (IMRD) in 1989. This restructuring resulted in the transfer in 1990 of the Department of Social Welfare and Development to the Office of the President. POPIN also serves Asia/Pacific POPIN. POPCOM makes policy and coordinates and monitors population activities. POPIN's goal is to improve the flow and utilization of population information nationwide. The National Population Library was moved in 1989 to the POPCOM Central Office Building and became the Philippine Information Center. The collection includes 6000 books, 400 research reports, and 4000 other documents (brochures, reprints, conference materials, and so on); 42 video tapes about the Philippine population program and a cassette player are available. In 1989, 14 regional centers were set up in POPCOM regional offices and designated Regional Population Information Centers. There are also school-based information centers operating as satellite information centers. The Regional and school-based centers serve the purpose of providing technical information through collection development, cataloguing, classification, storage and retrieval, and circulation. The target users are policy makers, government and private research agencies, researchers, and faculty and students. Publications developed and produced by the Center include the 3rd Supplement of the Union Catalogue of Population Literature, the 1987-88 Annotated Bibliography of Philippine Population Literature (PPL), the forthcoming 1989-90 edition of the Annotated Bibliography of PPL, and a biyearly newsletter, POPINEWS. Microcomputers have been acquired for the Regional Centers, with the idea of computerizing POPIN. Computer upgrading is also being done within the IMRD to provide POPLINE CD

  7. New light on old problem: population.

    PubMed

    Padilla, T

    1982-01-01

    A central issue of the Third Asian and Pacific Population Conference, to be held in Sri Lanka in September 1982, is the need for full recognition on the part of developing countries that an integrated approach to population and development is essential. Such an approach requires the following: management of internal migration and urbanization; women's participation in development; and increased involvement in promoting family planning, family welfare, and family health programs. Of much concern is the fact that the ESCAP region's urban population is projected to grow from 660 million in 1980 to 1347 million by the year 2000. Much of this increase will occur in the largest cities. Unplanned urbanization and a growing population reservoir in rural areas will continue to spur movements to the cities, aggravating the urban malaise, yet migration is young people's only option if rural populations are to survive. These problems plague most governments. A recent conference held in Rome urged governments to formulate comprehensive population policies and programs, to specify goals on the rate of population growth and on the distribution of population between urban and rural areas, and to plan for the redistribution of population. The conference also recommended that cities pay attention to problems of the shantytown and slum dwellers who are principally rural migrants and the urban poor. In addition the region's corps of development planners and experts worry about the staggering increase in migration by 3rd world guest workers to the high income OPEC members in the Middle East and the industrialized market economy nations. The proper management of international migration should increase the reabsorptive capacity of sending countries to ensure the reintegration of returning off-loaded guest workers and should try to prevent the rural stagnation due to large scale migration by the young and the better educated from the countryside. Internal and international migration give

  8. Population Growth Types in India, 1961-71

    ERIC Educational Resources Information Center

    Chakravarti, A. K.

    1976-01-01

    An effective means of cartographic representation of India's population growth and its spatial characteristics is the focus of this paper. A population growth index and population growth types are discussed. (Author/ND)

  9. Social Organization, Population, and Land Use*

    PubMed Central

    Axinn, William G.; Ghimire, Dirgha J.

    2011-01-01

    We present a new approach to the investigation of human influences on environmental change that explicitly adds consideration of social organization. This approach identifies social organization as an influence on the environment that is independent of population size, affluence, and technology. The framework we present also identifies population events, such as births, that are likely to influence environmental outcomes beyond the consequences of population size. The theoretical framework we construct explains that explicit attention to social organization is necessary for micro-level investigation of the population-environment relationship because social organization influences both. We use newly available longitudinal, multilevel, mixed-method measures of local land use changes, local population dynamics, and social organization from the Nepalese Himalayas to provide empirical tests of this new framework. These tests reveal that measures of change in social organization are strongly associated with measures of change in land use, and that the association is independent of common measures of population size, affluence, and technology. Also, local birth events shape local land use changes and key proximate determinants of land use change. Together the empirical results demonstrate key new scientific opportunities arising from the approach we present. PMID:21876607

  10. Population Structure With Localized Haplotype Clusters

    PubMed Central

    Browning, Sharon R.; Weir, Bruce S.

    2010-01-01

    We propose a multilocus version of FST and a measure of haplotype diversity using localized haplotype clusters. Specifically, we use haplotype clusters identified with BEAGLE, which is a program implementing a hidden Markov model for localized haplotype clustering and performing several functions including inference of haplotype phase. We apply this methodology to HapMap phase 3 data. With this haplotype-cluster approach, African populations have highest diversity and lowest divergence from the ancestral population, East Asian populations have lowest diversity and highest divergence, and other populations (European, Indian, and Mexican) have intermediate levels of diversity and divergence. These relationships accord with expectation based on other studies and accepted models of human history. In contrast, the population-specific FST estimates obtained directly from single-nucleotide polymorphisms (SNPs) do not reflect such expected relationships. We show that ascertainment bias of SNPs has less impact on the proposed haplotype-cluster-based FST than on the SNP-based version, which provides a potential explanation for these results. Thus, these new measures of FST and haplotype-cluster diversity provide an important new tool for population genetic analysis of high-density SNP data. PMID:20457877

  11. Impacts of Insect Herbivores on Plant Populations.

    PubMed

    Myers, Judith H; Sarfraz, Rana M

    2017-01-31

    Apparent feeding damage by insects on plants is often slight. Thus, the influences of insect herbivores on plant populations are likely minor. The role of insects on host-plant populations can be elucidated via several methods: stage-structured life tables of plant populations manipulated by herbivore exclusion and seed-addition experiments, tests of the enemy release hypothesis, studies of the effects of accidentally and intentionally introduced insect herbivores, and observations of the impacts of insect species that show outbreak population dynamics. These approaches demonstrate that some, but not all, insect herbivores influence plant population densities. At times, insect-feeding damage kills plants, but more often, it reduces plant size, growth, and seed production. Plant populations for which seed germination is site limited will not respond at the population level to reduced seed production. Insect herbivores can influence rare plant species and need to be considered in conservation programs. Alterations due to climate change in the distributions of insect herbivores indicate the possibility of new influences on host plants. Long-term studies are required to show if density-related insect behavior stabilizes plant populations or if environmental variation drives most temporal fluctuations in plant densities. Finally, insects can influence plant populations and communities through changing the diversity of nonhost species, modifying nutrient fluxes, and rejuvenating over mature forests.

  12. Weak ergodicity of population evolution processes.

    PubMed

    Inaba, H

    1989-10-01

    The weak ergodic theorems of mathematical demography state that the age distribution of a closed population is asymptotically independent of the initial distribution. In this paper, we provide a new proof of the weak ergodic theorem of the multistate population model with continuous time. The main tool to attain this purpose is a theory of multiplicative processes, which was mainly developed by Garrett Birkhoff, who showed that ergodic properties generally hold for an appropriate class of multiplicative processes. First, we construct a general theory of multiplicative processes on a Banach lattice. Next, we formulate a dynamical model of a multistate population and show that its evolution operator forms a multiplicative process on the state space of the population. Subsequently, we investigate a sufficient condition that guarantees the weak ergodicity of the multiplicative process. Finally, we prove the weak and strong ergodic theorems for the multistate population and resolve the consistency problem.

  13. Optimization models for degrouping population data.

    PubMed

    Bermúdez, Silvia; Blanquero, Rafael

    2016-07-01

    In certain countries population data are available in grouped form only, usually as quinquennial age groups plus a large open-ended range for the elderly. However, official statistics call for data by individual age since many statistical operations, such as the calculation of demographic indicators, require the use of ungrouped population data. In this paper a number of mathematical models are proposed which, starting from population data given in age groups, enable these ranges to be degrouped into age-specific population values without leaving a fractional part. Unlike other existing procedures for disaggregating demographic data, ours makes it possible to process several years' data simultaneously in a coherent way, and provides accurate results longitudinally as well as transversally. This procedure is also shown to be helpful in dealing with degrouped population data affected by noise, such as those affected by the age-heaping phenomenon.

  14. Fertility decline and population growth: China's dilemma.

    PubMed

    Gu, B

    1996-02-01

    This article includes the assertion by the deputy director and demographer of the China Information and Research Center that China must maintain and implement a strict population policy in order to feed its large population. China has 22% of the world's total population but only 7% of the world's total cultivated land. The population rate varies by province and region in China and ranges from replacement level fertility in Shanghai to high growth in remote and underdeveloped provinces. About 70 million people live under the poverty line or have an annual family income of under 500 yuan. The family planning programs should emphasize a service oriented approach. The increased power of women and improved educational status of women are also desired. Concern is recognized in government circles about the rapid aging of the population. Rural-urban migration has improved the economic climate in cities, but migration has also resulted in "some serious social problems." China has a low fertility level but rapid population growth. In the 1990s about 21 million babies were born, which is a net increase of about 14 million annually. Population growth is serious because of a strong population momentum from the previous baby boom of the 1960s. China has accomplished a great deal in a short period of time in reducing fertility under unfavorable socioeconomic conditions. Credit must be given to the Chinese government, its various departments, and public response. Present population is over 1.2 billion, which is higher than the total population of developed countries of the world.

  15. [On the rational distribution of Chinese population].

    PubMed

    Zhu, Z

    1980-01-01

    In 1949, the population distribution in China was characterized by the following distinct features. First, it was unbalanced, with high density in the eastern regions, in the plains, and in areas adjacent to railroads, river navigation routes and other transportation axes. Low population density was found in the western regions, mountainous regions, and areas far from transportation routes. Second, Hans were largest in number and distributed throughout the country, with major concentration in the eastern regions, while the minorities constituted about 10% of the total population and were distributed mainly in the far southwestern and northwestern areas. Third, over 89% of the 540 million of the population was distributed in rural areas while only about 10% in towns and cities, with high densities in some coastal cities. During the past 3 decades, the unbalanced nature of China's population has remained basically unchanged. This can be attributed to factors relating to natural conditions and resources, productivities, socioeconomic conditions, and technological development in different regions. In order to achieve a rational distribution of the Chinese population the following measures should be taken: 1) controlling the birth rate of the Hans and increasing the population of minorities; 2) moving the population of the dense areas to the border provinces in the western regions to develop their natural resources and to elevate the living standards; 3) modernizing the rural areas; 4) strictly controlling the industrial developments of large cities and their population growth; and 5) strictly restricting the unplanned migration of population to and from cities.

  16. Evolutionary Game Theory in Growing Populations

    NASA Astrophysics Data System (ADS)

    Melbinger, Anna; Cremer, Jonas; Frey, Erwin

    2010-10-01

    Existing theoretical models of evolution focus on the relative fitness advantages of different mutants in a population while the dynamic behavior of the population size is mostly left unconsidered. We present here a generic stochastic model which combines the growth dynamics of the population and its internal evolution. Our model thereby accounts for the fact that both evolutionary and growth dynamics are based on individual reproduction events and hence are highly coupled and stochastic in nature. We exemplify our approach by studying the dilemma of cooperation in growing populations and show that genuinely stochastic events can ease the dilemma by leading to a transient but robust increase in cooperation.

  17. Population research potentials in Africa.

    PubMed

    Hyden, G

    1980-01-01

    There is a need in Africa to test prevailing theories and concepts in population studies to see how they apply to this culture. Most of the prevailing perspective on population issues can be influenced by development strategies and policies affecting demographic variables. So research designed to determine the longterm consequences of rural settlement policies on subsequent access to family planning or family planning policies are also needed, as are studies which zero in on the work and results of specific population projects. The following issues are considered worth special consideration in Africa, where the vast majority of women live in rural areas where family planning services will not reach for some time. The areas of investigation which seem most pertinent in sub-saharan Africa are: side effect of contraceptive devices and agents; infertility assessments, social and medical consequences of adolescent pregnancies, the means of offering effective population education in rural African areas, the possible effects of fertility control programs on demographic transition, and potential funding sources.

  18. New Model for Population-Subpopulation Differences

    DTIC Science & Technology

    2007-02-01

    EDGEWOOD CHEMICAL BIOLOGICAL CENTER U.S. ARMY RESEARCH, DEVELOPMENT AND ENGINEERING COMMAND ECBC-TR-534 NEW MODEL FOR POPULATION-SUBPOPULATION...DATES COVERED (From - To) XX-02-2007 Final Nov 2005 - Nov 2006 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER New Model for Population-Subpopulation...susceptibilities for both the general population and the military subpopulation were modeled by a lognormal distribution. The assumption of a lognormal distribution

  19. Population-specific life histories contribute to metapopulation viability

    USGS Publications Warehouse

    Halsey, Samniqueka J.; Bell, Timothy J.; McEachern, A. Kathryn; Pavlovic, Noel B.

    2016-01-01

    Restoration efforts can be improved by understanding how variations in life-history traits occur within populations of the same species living in different environments. This can be done by first understanding the demographic responses of natural occurring populations. Population viability analysis continues to be useful to species management and conservation with sensitivity analysis aiding in the understanding of population dynamics. In this study, using life-table response experiments and elasticity analyses, we investigated how population-specific life-history demographic responses contributed to the metapopulation viability of the Federally threatened Pitcher's thistle (Cirsium pitcheri). Specifically, we tested the following hypotheses: (1) Subpopulations occupying different environments within a metapopulation have independent demographic responses and (2) advancing succession results in a shift from a demographic response focused on growth and fecundity to one dominated by stasis. Our results showed that reintroductions had a positive contribution to the metapopulation growth rate as compared to native populations which had a negative contribution. We found no difference in succession on the contribution to metapopulation viability. In addition, we identified distinct population-specific contributions to metapopulation viability and were able to associate specific life-history demographic responses. For example, the positive impact of Miller High Dunes population on the metapopulation growth rate resulted from high growth contributions, whereas increased time of plant in stasis for the State Park Big Blowout population resulted in negative contributions. A greater understanding of how separate populations respond in their corresponding environment may ultimately lead to more effective management strategies aimed at reducing extinction risk. We propose the continued use of sensitivity analyses to evaluate population-specific demographic influences on

  20. Population density and suicide in Scotland.

    PubMed

    Stark, Cameron; Hopkins, Paddy; Gibbs, Diane; Belbin, Alan; Hay, Alistair

    2007-01-01

    Suicide rates among men have increased in Scotland while falling in neighbouring countries. A national suicide prevention strategy has been produced. Previous work found that some rural areas of Scotland had higher than average rates of male suicide and undetermined deaths. This article describes the association between population density and suicide and undetermined death rates in Scotland. Anonymised information on deaths from suicide and undetermined cause in Scotland were obtained from the General Registrar Office for 1981-1999, including information on postcode sector. Each postcode sector was assigned a deprivation and population density score. Loglinear models were used to examine the effects of time period (grouped into four periods), deprivation quintiles, population density (grouped into four categories) and their interactions in each sex in three age groups. A significance level of 5% was used throughout. Adjusted rate ratios and 95% confidence intervals were based on models that included only significant factors and interactions. In men, there were higher rate ratios in the most densely populated and least densely populated quartiles, with intermediate rate ratios in other areas. There was no association with population density in women aged less than 25 years, a similar pattern to men in 25-44 year old women, and lower rates in rural areas in older women. Higher levels of deprivation were associated with higher rate ratios of suicide in both sexes and all age groups. Rate ratios over time increased in younger men and women, remained stable in older men, and declined in older women. Deprivation is associated with higher rates of suicide and undetermined deaths at all levels of population density and in all age groups. The highest rates of suicide among men are in the most and least densely populated areas, after adjusting for deprivation. The effect is different among women, with no effect among younger women, and lower rates among older women in areas

  1. Population Annealing Monte Carlo for Frustrated Systems

    NASA Astrophysics Data System (ADS)

    Amey, Christopher; Machta, Jonathan

    Population annealing is a sequential Monte Carlo algorithm that efficiently simulates equilibrium systems with rough free energy landscapes such as spin glasses and glassy fluids. A large population of configurations is initially thermalized at high temperature and then cooled to low temperature according to an annealing schedule. The population is kept in thermal equilibrium at every annealing step via resampling configurations according to their Boltzmann weights. Population annealing is comparable to parallel tempering in terms of efficiency, but has several distinct and useful features. In this talk I will give an introduction to population annealing and present recent progress in understanding its equilibration properties and optimizing it for spin glasses. Results from large-scale population annealing simulations for the Ising spin glass in 3D and 4D will be presented. NSF Grant DMR-1507506.

  2. Microsatellite and Wolbachia analysis in Rhagoletis cerasi natural populations: population structuring and multiple infections.

    PubMed

    Augustinos, Antonios A; Asimakopoulou, Anastasia K; Moraiti, Cleopatra A; Mavragani-Tsipidou, Penelope; Papadopoulos, Nikolaos T; Bourtzis, Kostas

    2014-05-01

    Rhagoletis cerasi (Diptera: Tephritidae) is a major pest of sweet and sour cherries in Europe and parts of Asia. Despite its economic significance, there is a lack of studies on the genetic structure of R. cerasi populations. Elucidating the genetic structure of insects of economic importance is crucial for developing phenological-predictive models and environmental friendly control methods. All natural populations of R. cerasi have been found to harbor the endosymbiont Wolbachia pipientis, which widely affects multiple biological traits contributing to the evolution of its hosts, and has been suggested as a tool for the biological control of insect pests and disease vectors. In the current study, the analysis of 18 R. cerasi populations collected in Greece, Germany, and Russia using 13 microsatellite markers revealed structuring of R. cerasi natural populations, even at close geographic range. We also analyzed the Wolbachia infection status of these populations using 16S rRNA-, MLST- and wsp-based approaches. All 244 individuals screened were positive for Wolbachia. Our results suggest the fixation of the wCer1 strain in Greece while wCer2, wCer4, wCer5, and probably other uncharacterized strains were also detected in multiply infected individuals. The role of Wolbachia and its potential extended phenotypes needs a thorough investigation in R. cerasi. Our data suggest an involvement of this symbiont in the observed restriction in the gene flow in addition to a number of different ecological factors.

  3. Into the depth of population genetics: pattern of structuring in mesophotic red coral populations

    NASA Astrophysics Data System (ADS)

    Costantini, Federica; Abbiati, Marco

    2016-03-01

    Deep-sea reef-building corals are among the most conspicuous invertebrates inhabiting the hard-bottom habitats worldwide and are particularly susceptible to human threats. The precious red coral ( Corallium rubrum, L. 1758) has a wide bathymetric distribution, from shallow up to 800 m depth, and represents a key species in the Mediterranean mesophotic reefs. Several studies have investigated genetic variability in shallow-water red coral populations, while geographic patterns in mesophotic habitats are largely unknown. This study investigated genetic variability of C. rubrum populations dwelling between 55 and 120 m depth, from the Ligurian to the Ionian Sea along about 1500 km of coastline. A total of 18 deep rocky banks were sampled. Colonies were analyzed by means of a set of microsatellite loci and the putative control region of the mitochondrial DNA. Collected data were compared with previous studies. Both types of molecular markers showed high genetic similarity between populations within the northern (Ligurian Sea and Tuscan Archipelago) and the southern (Tyrrhenian and Ionian seas) study areas. Variability in habitat features between the sampling sites did not affect the genetic variability of the populations. Conversely, the patchy distribution of suitable habitats affected populations' connectivity within and among deep coral banks. Based on these results and due to the emphasis on red coral protection in the Mediterranean Sea by international institutions, red coral could be promoted as a `focal species' to develop management plans for the conservation of deep coralligenous reefs, a reservoir of marine biodiversity.

  4. Microsatellite and Wolbachia analysis in Rhagoletis cerasi natural populations: population structuring and multiple infections

    PubMed Central

    Augustinos, Antonios A; Asimakopoulou, Anastasia K; Moraiti, Cleopatra A; Mavragani-Tsipidou, Penelope; Papadopoulos, Nikolaos T; Bourtzis, Kostas

    2014-01-01

    Rhagoletis cerasi (Diptera: Tephritidae) is a major pest of sweet and sour cherries in Europe and parts of Asia. Despite its economic significance, there is a lack of studies on the genetic structure of R. cerasi populations. Elucidating the genetic structure of insects of economic importance is crucial for developing phenological-predictive models and environmental friendly control methods. All natural populations of R. cerasi have been found to harbor the endosymbiont Wolbachia pipientis, which widely affects multiple biological traits contributing to the evolution of its hosts, and has been suggested as a tool for the biological control of insect pests and disease vectors. In the current study, the analysis of 18 R. cerasi populations collected in Greece, Germany, and Russia using 13 microsatellite markers revealed structuring of R. cerasi natural populations, even at close geographic range. We also analyzed the Wolbachia infection status of these populations using 16S rRNA-, MLST- and wsp-based approaches. All 244 individuals screened were positive for Wolbachia. Our results suggest the fixation of the wCer1 strain in Greece while wCer2, wCer4, wCer5, and probably other uncharacterized strains were also detected in multiply infected individuals. The role of Wolbachia and its potential extended phenotypes needs a thorough investigation in R. cerasi. Our data suggest an involvement of this symbiont in the observed restriction in the gene flow in addition to a number of different ecological factors. PMID:24963388

  5. Employment population age-share differences: an international comparison of the economic impact of population aging.

    PubMed

    Brucker, Eric

    2009-01-01

    International comparisons of the economic impact of population aging across nations can give valuable insights regarding which policies are most effective in addressing aging-related economic issues. Traditional old-age dependency ratios, by not accounting for differences in labor force participation rates, can be misleading. A new measure, the difference between an age group's share of total employment and its share of the total adult population, is developed and shown to be empirically sensitive to different policy actions. The analysis is built upon readily available and comparable International Labour Organization age-group data on population and labor force participation rates.

  6. CKD in disadvantaged populations.

    PubMed

    Garcia-Garcia, Guillermo; Jha, Vivekanand

    2015-02-01

    The increased burden of CKD in disadvantaged populations is due to both global factors and population-specific issues. Low socioeconomic status and poor access to care contribute to health-care disparities and exacerbate the negative effects of genetic or biologic predisposition. Provision of appropriate renal care to these populations requires a two-pronged approach: expansion of the reach of dialysis through development of low-cost alternatives that can be practiced in remote locations, and implementation and evaluation of cost-effective prevention strategies. Kidney transplantation should be promoted by expansion of deceased-donor transplant programs and use of inexpensive, generic immunosuppressive drugs. The message of WKD 2015 is that a concerted attack against the diseases that lead to ESRD, by increased community outreach, better education, improved economic opportunity, and access to preventive medicine for those at highest risk, could end the unacceptable relationship between CKD and disadvantage in these communities.

  7. Recombination gives a new insight in the effective population size and the history of the old world human populations.

    PubMed

    Melé, Marta; Javed, Asif; Pybus, Marc; Zalloua, Pierre; Haber, Marc; Comas, David; Netea, Mihai G; Balanovsky, Oleg; Balanovska, Elena; Jin, Li; Yang, Yajun; Pitchappan, R M; Arunkumar, G; Parida, Laxmi; Calafell, Francesc; Bertranpetit, Jaume

    2012-01-01

    The information left by recombination in our genomes can be used to make inferences on our recent evolutionary history. Specifically, the number of past recombination events in a population sample is a function of its effective population size (Ne). We have applied a method, Identifying Recombination in Sequences (IRiS), to detect specific past recombination events in 30 Old World populations to infer their Ne. We have found that sub-Saharan African populations have an Ne that is approximately four times greater than those of non-African populations and that outside of Africa, South Asian populations had the largest Ne. We also observe that the patterns of recombinational diversity of these populations correlate with distance out of Africa if that distance is measured along a path crossing South Arabia. No such correlation is found through a Sinai route, suggesting that anatomically modern humans first left Africa through the Bab-el-Mandeb strait rather than through present Egypt.

  8. The Why and How of Population Education

    ERIC Educational Resources Information Center

    Seffrin, John R.

    1975-01-01

    Discusses the importance of instructional programs concerning population education and describes population growth in the United States, the biological reasons for the overpopulation problem, and the role of the health educator in population education. (BD)

  9. Phenotypic diversity, population structure and stress protein-based capacitoring in populations of Xeropicta derbentina, a heat-tolerant land snail species.

    PubMed

    Di Lellis, Maddalena A; Sereda, Sergej; Geißler, Anna; Picot, Adrien; Arnold, Petra; Lang, Stefanie; Troschinski, Sandra; Dieterich, Andreas; Hauffe, Torsten; Capowiez, Yvan; Mazzia, Christophe; Knigge, Thomas; Monsinjon, Tiphaine; Krais, Stefanie; Wilke, Thomas; Triebskorn, Rita; Köhler, Heinz-R

    2014-11-01

    The shell colour of many pulmonate land snail species is highly diverse. Besides a genetic basis, environmentally triggered epigenetic mechanisms including stress proteins as evolutionary capacitors are thought to influence such phenotypic diversity. In this study, we investigated the relationship of stress protein (Hsp70) levels with temperature stress tolerance, population structure and phenotypic diversity within and among different populations of a xerophilic Mediterranean snail species (Xeropicta derbentina). Hsp70 levels varied considerably among populations, and were significantly associated with shell colour diversity: individuals in populations exhibiting low diversity expressed higher Hsp70 levels both constitutively and under heat stress than those of phenotypically diverse populations. In contrast, population structure (cytochrome c oxidase subunit I gene) did not correlate with phenotypic diversity. However, genetic parameters (both within and among population differences) were able to explain variation in Hsp70 induction at elevated but non-pathologic temperatures. Our observation that (1) population structure had a high explanatory potential for Hsp70 induction and that (2) Hsp70 levels, in turn, correlated with phenotypic diversity while (3) population structure and phenotypic diversity failed to correlate provides empirical evidence for Hsp70 to act as a mediator between genotypic variation and phenotype and thus for chaperone-driven evolutionary capacitance in natural populations.

  10. Information, Education, Communication in Population.

    ERIC Educational Resources Information Center

    Hawaii Univ., Honolulu. East-West Center.

    Programs and services of the Swedish International Development Authority (SIDA) are reviewed in this report on resources available for the support of population information, education, and communication activities. Four major sections describe in concise, outline form: (1) the agency and its programs, (2) the specific program in population/family…

  11. Considering the needs of English language learner populations: an examination of the population validity of reading intervention research.

    PubMed

    Moore, Brooke A; Klingner, Janette K

    2014-01-01

    This article synthesizes reading intervention research studies intended for use with struggling or at-risk students to determine which studies adequately address population validity, particularly in regard to the diverse reading needs of English language learners. An extensive search of the professional literature between 2001 and 2010 yielded a total of 67 reading intervention studies targeting at-risk elementary students. Findings revealed that many current research studies fail to adequately describe the sample, including the accessible and target populations, and to disaggregate their findings based on demographic characteristics. When population validity issues are not addressed, researchers cannot generalize findings to other populations of students, and it becomes unclear what intervention strategies work, especially with English language learner student populations. However, 25 studies did specifically recognize and address the needs of English language learners, indicating more researchers are taking into consideration the diverse needs of other struggling student populations. © Hammill Institute on Disabilities 2012.

  12. Spatial and temporal dynamics of fucoid populations (Ascophyllum nodosum and Fucus serratus): a comparison between central and range edge populations.

    PubMed

    Araújo, Rita M; Serrão, Ester A; Sousa-Pinto, Isabel; Åberg, Per

    2014-01-01

    Persistence of populations at range edges relies on local population dynamics and fitness, in the case of geographically isolated populations of species with low dispersal potential. Focusing on spatial variations in demography helps to predict the long-term capability for persistence of populations across the geographical range of species' distribution. The demography of two ecological and phylogenetically close macroalgal species with different life history characteristics was investigated by using stochastic, stage-based matrix models. Populations of Ascophyllum nodosum and Fucus serratus were sampled for up to 4 years at central locations in France and at their southern range limits in Portugal. The stochastic population growth rate (λ(s)) of A. nodosum was lower and more variable in central than in southern sites whilst for F. serratus this trend was reversed with λ(s) much lower and more variable in southern than in central populations. Individuals were larger in central than in southern populations for both species, which was reflected in the lower transition probabilities of individuals to larger size classes and higher probability of shrinkage in the southern populations. In both central and southern populations elasticity analysis (proportional sensitivity) of population growth rate showed that fertility elements had a small contribution to λ(s) that was more sensitive to changes in matrix transitions corresponding to survival. The highest elasticities were found for loop transitions in A. nodosum and for growth to larger size classes in F. serratus. Sensitivity analysis showed high selective pressure on individual growth for both species at both locations. The results of this study highlight the deterministic role of species-specific life-history traits in population demography across the geographical range of species. Additionally, this study demonstrates that individuals' life-transitions differ in vulnerability to environmental variability and

  13. World Population: Toward the Next Century. Revised Edition.

    ERIC Educational Resources Information Center

    Murphy, Elaine M.

    This document consists of answers to questions on various aspects of world population. They are: What is the population of the world? How fast is the population of the world growing? When will the population of the world stop growing? Is the term "population explosion" accurate? Why did this sudden growth occur? Did people have more babies than…

  14. Population structure of Helicobacter pylori among ethnic groups in Malaysia: recent acquisition of the bacterium by the Malay population

    PubMed Central

    2009-01-01

    Background Helicobacter pylori is a major gastric bacterial pathogen. This pathogen has been shown to follow the routes of human migration by their geographical origin and currently the global H. pylori population has been divided into six ancestral populations, three from Africa, two from Asia and one from Europe. Malaysia is made up of three major ethnic populations, Malay, Chinese and Indian, providing a good population for studying recent H. pylori migration and admixture. Results Seventy eight H. pylori isolates, including 27 Chinese, 35 Indian and 16 Malay isolates from Malaysia were analysed by multilocus sequence typing (MLST) of seven housekeeping genes and compared with the global MLST data. STRUCTURE analysis assigned the isolates to previously identified H. pylori ancestral populations, hpEastAsia, hpAsia2 and hpEurope, and revealed a new subpopulation, hspIndia, within hpAsia2. Statistical analysis allowed us to identify population segregation sites that divide the H. pylori populations and the subpopulations. The majority of Malay isolates were found to be grouped together with Indian isolates. Conclusion The majority of the Malay and Indian H. pylori isolates share the same origin while the Malaysian Chinese H. pylori is distinctive. The Malay population, known to have a low infection rate of H. pylori, was likely to be initially H. pylori free and gained the pathogen only recently from cross infection from other populations. PMID:19538757

  15. X-chromosome as a marker for population history: linkage disequilibrium and haplotype study in Eurasian populations

    PubMed Central

    Laan, Maris; Wiebe, Victor; Khusnutdinova, Elza; Remm, Maido; Pääbo, Svante

    2005-01-01

    Linkage disequilibrium structure is still unpredictable because the interplay of regional recombination rate and demographic history is poorly understood. We have compared the distribution of LD across two genomic regions differing in crossing-over activity – Xq13 (0.166 cM/Mb) and Xp22 (1.3 cM/Mb) – in 15 Eurasian populations. Demographic events predicted to increase the LD level – genetic drift, bottleneck and admixture – had a very strong impact on extent and patterns of regional LD across Xq13 compared to Xp22. The haplotype distribution of the DXS1225-DXS8082 microsatellites from Xq13 exhibiting strong association in all populations was remarkably influenced by population history. European populations shared one common haplotype with a frequency of 25-40%. The Volga-Ural populations studied, living at the geographic borderline of Europe, showed elevated LD as well as harboring a significant fraction of haplotypes originating from East Asia, thus reflecting their past migrations and admixture. In the young Kuusamo isolate from Finland, a bottleneck has led to allelic associations between loci and shifted the haplotype distribution, but has much less affected single microsatellite allele frequencies compared to the main Finnish population. The data show that the footprint of a demographic event is longer preserved in haplotype distribution within a region of low crossing-over rate, than in the information content of a single marker, or between actively recombining markers. As the knowledge of LD patterns is often chosen to assist association mapping of common disease, our conclusions emphasise the importance of understanding the history, structure and variation of a study population. PMID:15657606

  16. Reliability of Different Mark-Recapture Methods for Population Size Estimation Tested against Reference Population Sizes Constructed from Field Data

    PubMed Central

    Grimm, Annegret; Gruber, Bernd; Henle, Klaus

    2014-01-01

    Reliable estimates of population size are fundamental in many ecological studies and biodiversity conservation. Selecting appropriate methods to estimate abundance is often very difficult, especially if data are scarce. Most studies concerning the reliability of different estimators used simulation data based on assumptions about capture variability that do not necessarily reflect conditions in natural populations. Here, we used data from an intensively studied closed population of the arboreal gecko Gehyra variegata to construct reference population sizes for assessing twelve different population size estimators in terms of bias, precision, accuracy, and their 95%-confidence intervals. Two of the reference populations reflect natural biological entities, whereas the other reference populations reflect artificial subsets of the population. Since individual heterogeneity was assumed, we tested modifications of the Lincoln-Petersen estimator, a set of models in programs MARK and CARE-2, and a truncated geometric distribution. Ranking of methods was similar across criteria. Models accounting for individual heterogeneity performed best in all assessment criteria. For populations from heterogeneous habitats without obvious covariates explaining individual heterogeneity, we recommend using the moment estimator or the interpolated jackknife estimator (both implemented in CAPTURE/MARK). If data for capture frequencies are substantial, we recommend the sample coverage or the estimating equation (both models implemented in CARE-2). Depending on the distribution of catchabilities, our proposed multiple Lincoln-Petersen and a truncated geometric distribution obtained comparably good results. The former usually resulted in a minimum population size and the latter can be recommended when there is a long tail of low capture probabilities. Models with covariates and mixture models performed poorly. Our approach identified suitable methods and extended options to evaluate the

  17. Evolutionary dynamics on any population structure

    NASA Astrophysics Data System (ADS)

    Allen, Benjamin; Lippner, Gabor; Chen, Yu-Ting; Fotouhi, Babak; Momeni, Naghmeh; Yau, Shing-Tung; Nowak, Martin A.

    2017-03-01

    Evolution occurs in populations of reproducing individuals. The structure of a population can affect which traits evolve. Understanding evolutionary game dynamics in structured populations remains difficult. Mathematical results are known for special structures in which all individuals have the same number of neighbours. The general case, in which the number of neighbours can vary, has remained open. For arbitrary selection intensity, the problem is in a computational complexity class that suggests there is no efficient algorithm. Whether a simple solution for weak selection exists has remained unanswered. Here we provide a solution for weak selection that applies to any graph or network. Our method relies on calculating the coalescence times of random walks. We evaluate large numbers of diverse population structures for their propensity to favour cooperation. We study how small changes in population structure—graph surgery—affect evolutionary outcomes. We find that cooperation flourishes most in societies that are based on strong pairwise ties.

  18. Oral medicine and the ageing population.

    PubMed

    Yap, T; McCullough, M

    2015-03-01

    The oral cavity is subject to age related processes such as cellular ageing and immunosenescence. The ageing population bears an increased burden of intraoral pathology. In oral medicine, the majority of presenting patients are in their fifth to seventh decade of life. In this review, we discuss the ageing population's susceptibility to mucosal disorders and the increased prevalence of potentially malignant disorders and oral squamous cell carcinoma, as well as dermatoses including oral lichen planus and immunobullous conditions. We also address the ageing population's susceptibility to oral discomfort and explore salivary secretion, ulceration and the symptoms of oral burning. Finally, we will describe orofacial pain conditions which are more likely encountered in an older population. This update highlights clinical presentations which are more likely to be encountered in the ageing population in a general practice setting and the importance of screening both new and long-term patients. © 2015 Australian Dental Association.

  19. Viability analysis in biological evaluations: Concepts of population viability analysis, biological population, and ecological scale

    Treesearch

    Gregory D. Hayward; John R. Squires

    1994-01-01

    Environmental protection strategies often rely on environmental impact assessments. As part of the assessment process biologists are routinely asked to evaluate the effects of management actions on plants and animals. This evaluation often requires that biologists make judgments about the viability of affected populations. However, population viability...

  20. Population structure of humpback whales in the western and central South Pacific Ocean as determined by vocal exchange among populations.

    PubMed

    Garland, Ellen C; Goldizen, Anne W; Lilley, Matthew S; Rekdahl, Melinda L; Garrigue, Claire; Constantine, Rochelle; Hauser, Nan Daeschler; Poole, M Michael; Robbins, Jooke; Noad, Michael J

    2015-08-01

    For cetaceans, population structure is traditionally determined by molecular genetics or photographically identified individuals. Acoustic data, however, has provided information on movement and population structure with less effort and cost than traditional methods in an array of taxa. Male humpback whales (Megaptera novaeangliae) produce a continually evolving vocal sexual display, or song, that is similar among all males in a population. The rapid cultural transmission (the transfer of information or behavior between conspecifics through social learning) of different versions of this display between distinct but interconnected populations in the western and central South Pacific region presents a unique way to investigate population structure based on the movement dynamics of a song (acoustic) display. Using 11 years of data, we investigated an acoustically based population structure for the region by comparing stereotyped song sequences among populations and years. We used the Levenshtein distance technique to group previously defined populations into (vocally based) clusters based on the overall similarity of their song display in space and time. We identified the following distinct vocal clusters: western cluster, 1 population off eastern Australia; central cluster, populations around New Caledonia, Tonga, and American Samoa; and eastern region, either a single cluster or 2 clusters, one around the Cook Islands and the other off French Polynesia. These results are consistent with the hypothesis that each breeding aggregation represents a distinct population (each occupied a single, terminal node) in a metapopulation, similar to the current understanding of population structure based on genetic and photo-identification studies. However, the central vocal cluster had higher levels of song-sharing among populations than the other clusters, indicating that levels of vocal connectivity varied within the region. Our results demonstrate the utility and value of

  1. The relative importance of intrinsic and extrinsic drivers to population growth vary among local populations of Greater Sage-Grouse: An integrated population modeling approach

    USGS Publications Warehouse

    Coates, Peter S.; Prochazka, Brian G.; Ricca, Mark A.; Halstead, Brian J.; Casazza, Michael L.; Blomberg, Erik J.; Brussee, Brianne E.; Wiechman, Lief; Tebbenkamp, Joel; Gardner, Scott C.; Reese, Kerry P.

    2018-01-01

    Consideration of ecological scale is fundamental to understanding and managing avian population growth and decline. Empirically driven models for population dynamics and demographic processes across multiple spatial scales can be powerful tools to help guide conservation actions. Integrated population models (IPMs) provide a framework for better parameter estimation by unifying multiple sources of data (e.g., count and demographic data). Hierarchical structure within such models that include random effects allow for varying degrees of data sharing across different spatiotemporal scales. We developed an IPM to investigate Greater Sage-Grouse (Centrocercus urophasianus) on the border of California and Nevada, known as the Bi-State Distinct Population Segment. Our analysis integrated 13 years of lek count data (n > 2,000) and intensive telemetry (VHF and GPS; n > 350 individuals) data across 6 subpopulations. Specifically, we identified the most parsimonious models among varying random effects and density-dependent terms for each population vital rate (e.g., nest survival). Using a joint likelihood process, we integrated the lek count data with the demographic models to estimate apparent abundance and refine vital rate parameter estimates. To investigate effects of climatic conditions, we extended the model to fit a precipitation covariate for instantaneous rate of change (r). At a metapopulation extent (i.e. Bi-State), annual population rate of change λ (er) did not favor an overall increasing or decreasing trend through the time series. However, annual changes in λ were driven by changes in precipitation (one-year lag effect). At subpopulation extents, we identified substantial variation in λ and demographic rates. One subpopulation clearly decoupled from the trend at the metapopulation extent and exhibited relatively high risk of extinction as a result of low egg fertility. These findings can inform localized, targeted management actions for specific areas

  2. Identifying Frailty Among Vulnerable Populations

    PubMed Central

    Salem, Benissa E.; Nyamathi, Adeline; Phillips, Linda R.; Mentes, Janet; Sarkisian, Catherine; Brecht, Lynn

    2014-01-01

    Frailty is a significant public health issue which is experienced by homeless and other vulnerable adults; to date, a frailty framework has not been proposed to guide researchers who study this hard-to-reach population. The Frailty Framework among Homeless and other Vulnerable Populations (FFHVP) has been developed from empirical research and consultation with frailty experts in an effort to characterize antecedents, i.e. situational, health-related, behavioral, resource, biological, and environmental factors which contribute to physical, psychological and social frailty domains and impact adverse outcomes. As vulnerable populations continue to age, a greater understanding of frailty will enable the development of nursing interventions. PMID:24469090

  3. Influence of language and ancestry on genetic structure of contiguous populations: A microsatellite based study on populations of Orissa

    PubMed Central

    Sahoo, Sanghamitra; Kashyap, VK

    2005-01-01

    Background We have examined genetic diversity at fifteen autosomal microsatellite loci in seven predominant populations of Orissa to decipher whether populations inhabiting the same geographic region can be differentiated on the basis of language or ancestry. The studied populations have diverse historical accounts of their origin, belong to two major ethnic groups and different linguistic families. Caucasoid caste populations are speakers of Indo-European language and comprise Brahmins, Khandayat, Karan and Gope, while the three Australoid tribal populations include two Austric speakers: Juang and Saora and a Dravidian speaking population, Paroja. These divergent groups provide a varied substratum for understanding variation of genetic patterns in a geographical area resulting from differential admixture between migrants groups and aboriginals, and the influence of this admixture on population stratification. Results The allele distribution pattern showed uniformity in the studied groups with approximately 81% genetic variability within populations. The coefficient of gene differentiation was found to be significantly higher in tribes (0.014) than caste groups (0.004). Genetic variance between the groups was 0.34% in both ethnic and linguistic clusters and statistically significant only in the ethnic apportionment. Although the populations were genetically close (FST = 0.010), the contemporary caste and tribal groups formed distinct clusters in both Principal-Component plot and Neighbor-Joining tree. In the phylogenetic tree, the Orissa Brahmins showed close affinity to populations of North India, while Khandayat and Gope clustered with the tribal groups, suggesting a possibility of their origin from indigenous people. Conclusions The extent of genetic differentiation in the contemporary caste and tribal groups of Orissa is highly significant and constitutes two distinct genetic clusters. Based on our observations, we suggest that since genetic distances and

  4. Genetic differentiation among North Atlantic killer whale populations.

    PubMed

    Foote, Andrew D; Vilstrup, Julia T; De Stephanis, Renaud; Verborgh, Philippe; Abel Nielsen, Sandra C; Deaville, Robert; Kleivane, Lars; Martín, Vidal; Miller, Patrick J O; Oien, Nils; Pérez-Gil, Monica; Rasmussen, Morten; Reid, Robert J; Robertson, Kelly M; Rogan, Emer; Similä, Tiu; Tejedor, Maria L; Vester, Heike; Víkingsson, Gísli A; Willerslev, Eske; Gilbert, M Thomas P; Piertney, Stuart B

    2011-02-01

    Population genetic structure of North Atlantic killer whale samples was resolved from differences in allele frequencies of 17 microsatellite loci, mtDNA control region haplotype frequencies and for a subset of samples, using complete mitogenome sequences. Three significantly differentiated populations were identified. Differentiation based on microsatellite allele frequencies was greater between the two allopatric populations than between the two pairs of partially sympatric populations. Spatial clustering of individuals within each of these populations overlaps with the distribution of particular prey resources: herring, mackerel and tuna, which each population has been seen predating. Phylogenetic analyses using complete mitogenomes suggested two populations could have resulted from single founding events and subsequent matrilineal expansion. The third population, which was sampled at lower latitudes and lower density, consisted of maternal lineages from three highly divergent clades. Pairwise population differentiation was greater for estimates based on mtDNA control region haplotype frequencies than for estimates based on microsatellite allele frequencies, and there were no mitogenome haplotypes shared among populations. This suggests low or no female migration and that gene flow was primarily male mediated when populations spatially and temporally overlap. These results demonstrate that genetic differentiation can arise through resource specialization in the absence of physical barriers to gene flow. © 2010 Blackwell Publishing Ltd.

  5. Disease invasion risk in a growing population.

    PubMed

    Yuan, Sanling; van den Driessche, P; Willeboordse, Frederick H; Shuai, Zhisheng; Ma, Junling

    2016-09-01

    The spread of an infectious disease may depend on the population size. For simplicity, classic epidemic models assume homogeneous mixing, usually standard incidence or mass action. For standard incidence, the contact rate between any pair of individuals is inversely proportional to the population size, and so the basic reproduction number (and thus the initial exponential growth rate of the disease) is independent of the population size. For mass action, this contact rate remains constant, predicting that the basic reproduction number increases linearly with the population size, meaning that disease invasion is easiest when the population is largest. In this paper, we show that neither of these may be true on a slowly evolving contact network: the basic reproduction number of a short epidemic can reach its maximum while the population is still growing. The basic reproduction number is proportional to the spectral radius of a contact matrix, which is shown numerically to be well approximated by the average excess degree of the contact network. We base our analysis on modeling the dynamics of the average excess degree of a random contact network with constant population input, proportional deaths, and preferential attachment for contacts brought in by incoming individuals (i.e., individuals with more contacts attract more incoming contacts). In addition, we show that our result also holds for uniform attachment of incoming contacts (i.e., every individual has the same chance of attracting incoming contacts), and much more general population dynamics. Our results show that a disease spreading in a growing population may evade control if disease control planning is based on the basic reproduction number at maximum population size.

  6. SNPs and Haplotypes in Native American Populations

    PubMed Central

    Kidd, Judith R.; Friedlaender, Françoise; Pakstis, Andrew J.; Furtado, Manohar; Fang, Rixun; Wang, Xudong; Nievergelt, Caroline M.; Kidd, Kenneth K.

    2013-01-01

    Autosomal DNA polymorphisms can provide new information and understanding of both the origins of and relationships among modern Native American populations. At the same time that autosomal markers can be highly informative, they are also susceptible to ascertainment biases in the selection of the markers to use. Identifying markers that can be used for ancestry inference among Native American populations can be considered separate from identifying markers to further the quest for history. In the current study we are using data on nine Native American populations to compare the results based on a large haplotype-based dataset with relatively small independent sets of SNPs. We are interested in what types of limited datasets an individual laboratory might be able to collect are best for addressing two different questions of interest. First, how well can we differentiate the Native American populations and/or infer ancestry by assigning an individual to her population(s) of origin? Second, how well can we infer the historical/evolutionary relationships among Native American populations and their Eurasian origins. We conclude that only a large comprehensive dataset involving multiple autosomal markers on multiple populations will be able to answer both questions; different small sets of markers are able to answer only one or the other of these questions. Using our largest dataset we see a general increasing distance from Old World populations from North to South in the New World except for an unexplained close relationship between our Maya and Quechua samples. PMID:21913176

  7. Population Growth: Crisis and Challenge.

    ERIC Educational Resources Information Center

    Beaton, John R., Ed.; Doberenz, Alexander R., Ed.

    The proceedings of this first annual symposium on population growth considers the consequences of this growth, along with possible means of regulation. Topics of speeches include: Population Outlook in Asia (Irene Taeuber); Malnutrition is a Problem of Ecology (Paul Gyorgy); The Leisure Explosion (E. H. Storey); Effects of Pollution on Population…

  8. Population Genomics of Fungal and Oomycete Pathogens.

    PubMed

    Grünwald, Niklaus J; McDonald, Bruce A; Milgroom, Michael G

    2016-08-04

    We are entering a new era in plant pathology in which whole-genome sequences of many individuals of a pathogen species are becoming readily available. Population genomics aims to discover genetic mechanisms underlying phenotypes associated with adaptive traits such as pathogenicity, virulence, fungicide resistance, and host specialization, as genome sequences or large numbers of single nucleotide polymorphisms become readily available from multiple individuals of the same species. This emerging field encompasses detailed genetic analyses of natural populations, comparative genomic analyses of closely related species, identification of genes under selection, and linkage analyses involving association studies in natural populations or segregating populations resulting from crosses. The era of pathogen population genomics will provide new opportunities and challenges, requiring new computational and analytical tools. This review focuses on conceptual and methodological issues as well as the approaches to answering questions in population genomics. The major steps start with defining relevant biological and evolutionary questions, followed by sampling, genotyping, and phenotyping, and ending in analytical methods and interpretations. We provide examples of recent applications of population genomics to fungal and oomycete plant pathogens.

  9. Optimal savings and the value of population.

    PubMed

    Arrow, Kenneth J; Bensoussan, Alain; Feng, Qi; Sethi, Suresh P

    2007-11-20

    We study a model of economic growth in which an exogenously changing population enters in the objective function under total utilitarianism and into the state dynamics as the labor input to the production function. We consider an arbitrary population growth until it reaches a critical level (resp. saturation level) at which point it starts growing exponentially (resp. it stops growing altogether). This requires population as well as capital as state variables. By letting the population variable serve as the surrogate of time, we are still able to depict the optimal path and its convergence to the long-run equilibrium on a two-dimensional phase diagram. The phase diagram consists of a transient curve that reaches the classical curve associated with a positive exponential growth at the time the population reaches the critical level. In the case of an asymptotic population saturation, we expect the transient curve to approach the equilibrium as the population approaches its saturation level. Finally, we characterize the approaches to the classical curve and to the equilibrium.

  10. Optimal savings and the value of population

    PubMed Central

    Arrow, Kenneth J.; Bensoussan, Alain; Feng, Qi; Sethi, Suresh P.

    2007-01-01

    We study a model of economic growth in which an exogenously changing population enters in the objective function under total utilitarianism and into the state dynamics as the labor input to the production function. We consider an arbitrary population growth until it reaches a critical level (resp. saturation level) at which point it starts growing exponentially (resp. it stops growing altogether). This requires population as well as capital as state variables. By letting the population variable serve as the surrogate of time, we are still able to depict the optimal path and its convergence to the long-run equilibrium on a two-dimensional phase diagram. The phase diagram consists of a transient curve that reaches the classical curve associated with a positive exponential growth at the time the population reaches the critical level. In the case of an asymptotic population saturation, we expect the transient curve to approach the equilibrium as the population approaches its saturation level. Finally, we characterize the approaches to the classical curve and to the equilibrium. PMID:17984059

  11. Cooperation, cheating, and collapse in microbial populations

    NASA Astrophysics Data System (ADS)

    Gore, Jeff

    2012-02-01

    Natural populations can suffer catastrophic collapse in response to small changes in environmental conditions, and recovery after such a collapse can be exceedingly difficult. We have used laboratory yeast populations to study proposed early warning signals of impending extinction. Yeast cooperatively breakdown the sugar sucrose, meaning that there is a minimum number of cells required to sustain the population. We have demonstrated experimentally that the fluctuations in the population size increase in magnitude and become slower as the population approaches collapse. The cooperative nature of yeast growth on sucrose suggests that the population may be susceptible to cheater cells, which do not contribute to the public good and instead merely take advantage of the cooperative cells. We have confirmed this possibility experimentally by using a cheater yeast strain that lacks the gene encoding the cooperative behavior [1]. However, recent results in the lab demonstrate that the presence of a bacterial competitor may drive cooperation within the yeast population.[4pt] [1] Gore et al, Nature 459, 253 -- 256 (2009)

  12. Does source population size affect performance in new environments?

    PubMed Central

    Yates, Matthew C; Fraser, Dylan J

    2014-01-01

    Small populations are predicted to perform poorly relative to large populations when experiencing environmental change. To explore this prediction in nature, data from reciprocal transplant, common garden, and translocation studies were compared meta-analytically. We contrasted changes in performance resulting from transplantation to new environments among individuals originating from different sized source populations from plants and salmonids. We then evaluated the effect of source population size on performance in natural common garden environments and the relationship between population size and habitat quality. In ‘home-away’ contrasts, large populations exhibited reduced performance in new environments. In common gardens, the effect of source population size on performance was inconsistent across life-history stages (LHS) and environments. When transplanted to the same set of new environments, small populations either performed equally well or better than large populations, depending on life stage. Conversely, large populations outperformed small populations within native environments, but only at later life stages. Population size was not associated with habitat quality. Several factors might explain the negative association between source population size and performance in new environments: (i) stronger local adaptation in large populations and antagonistic pleiotropy, (ii) the maintenance of genetic variation in small populations, and (iii) potential environmental differences between large and small populations. PMID:25469166

  13. Accountable Care Organizations and Population Health Organizations.

    PubMed

    Casalino, Lawrence P; Erb, Natalie; Joshi, Maulik S; Shortell, Stephen M

    2015-08-01

    Accountable care organizations (ACOs) and hospitals are investing in improving "population health," by which they nearly always mean the health of the "population" of patients "attributed" by Medicare, Medicaid, or private health insurers to their organizations. But population health can and should also mean "the health of the entire population in a geographic area." We present arguments for and against ACOs and hospitals investing in affecting the socioeconomic determinants of health to improve the health of the population in their geographic area, and we provide examples of ACOs and hospitals that are doing so in a limited way. These examples suggest that ACOs and hospitals can work with other organizations in their community to improve population health. We briefly present recent proposals for such coalitions and for how they could be financed to be sustainable. Copyright © 2015 by Duke University Press.

  14. Using population viability analysis, genomics, and habitat suitability to forecast future population patterns of Little Owl Athene noctua across Europe.

    PubMed

    Andersen, Line Holm; Sunde, Peter; Pellegrino, Irene; Loeschcke, Volker; Pertoldi, Cino

    2017-12-01

    The agricultural scene has changed over the past decades, resulting in a declining population trend in many species. It is therefore important to determine the factors that the individual species depend on in order to understand their decline. The landscape changes have also resulted in habitat fragmentation, turning once continuous populations into metapopulations. It is thus increasingly important to estimate both the number of individuals it takes to create a genetically viable population and the population trend. Here, population viability analysis and habitat suitability modeling were used to estimate population viability and future prospects across Europe of the Little Owl Athene noctua , a widespread species associated with agricultural landscapes. The results show a high risk of population declines over the coming 100 years, especially toward the north of Europe, whereas populations toward the southeastern part of Europe have a greater probability of persistence. In order to be considered genetically viable, individual populations must count 1,000-30,000 individuals. As Little Owl populations of several countries count <30,000, and many isolated populations in northern Europe count <1,000 individuals, management actions resulting in exchange of individuals between populations or even countries are probably necessary to prevent losing <1% genetic diversity over a 100-year period. At a continental scale, a habitat suitability analysis suggested Little Owl to be affected positively by increasing temperatures and urban areas, whereas an increased tree cover, an increasing annual rainfall, grassland, and sparsely vegetated areas affect the presence of the owl negatively. However, the low predictive power of the habitat suitability model suggests that habitat suitability might be better explained at a smaller scale.

  15. Population mobility and trypanosomiasis in Africa*

    PubMed Central

    Prothero, R. Mansell

    1963-01-01

    Population mobility has long been established as a feature of life in Africa south of the Sahara. Even though it appears to be a factor in the spread of sleeping-sickness there do not seem to have been serious epidemics until the latter part of the nineteenth century and the early decades of the twentieth century. Various types of population movement of the present day and their possible relevance to trypanosomiasis are discussed. Density of population and settlement patterns are also important. Some of the changes in these which are relevant to trypanosomiasis are outlined and the need for more detailed information on these and on population mobility is emphasized. PMID:13986384

  16. Stochastic evolution in populations of ideas

    NASA Astrophysics Data System (ADS)

    Nicole, Robin; Sollich, Peter; Galla, Tobias

    2017-01-01

    It is known that learning of players who interact in a repeated game can be interpreted as an evolutionary process in a population of ideas. These analogies have so far mostly been established in deterministic models, and memory loss in learning has been seen to act similarly to mutation in evolution. We here propose a representation of reinforcement learning as a stochastic process in finite ‘populations of ideas’. The resulting birth-death dynamics has absorbing states and allows for the extinction or fixation of ideas, marking a key difference to mutation-selection processes in finite populations. We characterize the outcome of evolution in populations of ideas for several classes of symmetric and asymmetric games.

  17. Stochastic evolution in populations of ideas

    PubMed Central

    Nicole, Robin; Sollich, Peter; Galla, Tobias

    2017-01-01

    It is known that learning of players who interact in a repeated game can be interpreted as an evolutionary process in a population of ideas. These analogies have so far mostly been established in deterministic models, and memory loss in learning has been seen to act similarly to mutation in evolution. We here propose a representation of reinforcement learning as a stochastic process in finite ‘populations of ideas’. The resulting birth-death dynamics has absorbing states and allows for the extinction or fixation of ideas, marking a key difference to mutation-selection processes in finite populations. We characterize the outcome of evolution in populations of ideas for several classes of symmetric and asymmetric games. PMID:28098244

  18. Modeling the impact of the indigenous microbial population on the maximum population density of Salmonella on alfalfa.

    PubMed

    Rijgersberg, Hajo; Franz, Eelco; Nierop Groot, Masja; Tromp, Seth-Oscar

    2013-07-01

    Within a microbial risk assessment framework, modeling the maximum population density (MPD) of a pathogenic microorganism is important but often not considered. This paper describes a model predicting the MPD of Salmonella on alfalfa as a function of the initial contamination level, the total count of the indigenous microbial population, the maximum pathogen growth rate and the maximum population density of the indigenous microbial population. The model is parameterized by experimental data describing growth of Salmonella on sprouting alfalfa seeds at inoculum size, native microbial load and Pseudomonas fluorescens 2-79. The obtained model fits well to the experimental data, with standard errors less than ten percent of the fitted average values. The results show that the MPD of Salmonella is not only dictated by performance characteristics of Salmonella but depends on the characteristics of the indigenous microbial population like total number of cells and its growth rate. The model can improve the predictions of microbiological growth in quantitative microbial risk assessments. Using this model, the effects of preventive measures to reduce pathogenic load and a concurrent effect on the background population can be better evaluated. If competing microorganisms are more sensitive to a particular decontamination method, a pathogenic microorganism may grow faster and reach a higher level. More knowledge regarding the effect of the indigenous microbial population (size, diversity, composition) of food products on pathogen dynamics is needed in order to make adequate predictions of pathogen dynamics on various food products.

  19. Survival and Population Dynamics of the Marabou Stork in an Isolated Population, Swaziland

    PubMed Central

    Monadjem, Ara; Kane, Adam; Botha, Andre; Dalton, Desire; Kotze, Antoinette

    2012-01-01

    Investigating the ecology of long lived birds is particularly challenging owing to the time scales involved. Here an analysis is presented of a long term study of the survival and population dynamics of the marabou stork (Leptoptilos crumeniferus), a wide ranging scavenging bird from Sub-Saharan Africa. Using resightings data of tagged nestlings and free flying birds we show that the stork population can be divided into three general life stages with unique survival probabilities and fecundities. Fecundity of the storks is inversely related to rainfall during their breeding season. Corroborative evidence for a metapopulation structure is discussed highlighting the impact of the Swaziland birds on the ecology of the species in the broader region. The importance of tag loss or illegibility over time is highlighted. Clearly, any attempt at conserving a species will require a detailed understanding of its population structure, of the sort examined here. PMID:23029517

  20. Nepal [Population education in countries of the region].

    PubMed

    Rongong, R K

    1982-06-01

    In 1979 the Ministry of Education and Culture in Nepal, in collaboration with Unesco and the UN Fund for Population Activities (UNFPA), organized a National Planning and Development Meeting in Population Education. The objectives were to understand the concept and nature of population education and population education programs in Asia, to review the existing programs of population education initiated by various agencies in Nepal, and to develop guidelines for the formulation of a national population education program, both in school and out of school. All of these objectives were realized. Subsequently, a population education project was formulated for UNFPA funding, with the help of the Unesco Regional Team on Population Education. The primary goal of the project is to gear the entire system--formal and nonformal--to the realization of the potential role of education in the development efforts of the country and the interrelationships between the population situation and different aspects of quality of life at the micro and macro levels. The long range objectives of the program are as follows: develop in the target audience an insight into the interrelationships between population growth and the process of social and economic development at the individual, family, society, national, and international levels; develop desirable attitudes and behavior in the teachers, students, and the community at large towards population issues so that they may make rational decisions about their family size and the quality of life that they would like to have; and institutionalize population education in the formal education system, including university, and the nonformal education program of the Ministry of Education. In a 1981 population education curriculum development workshop, 2 further objectives were added: develop in learners a knowledge and understanding of basic concepts, processes, and measures; and develop among learners an awareness of the attitudes, beliefs, and