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Sample records for clonogenic populations cfu-c

  1. Hematological effects: comparative studies on the radiation survival characteristics in vivo and in vitro of bone marrow-derived clonogenic populations (CFU-C and PFU-C) and some observations on bone marrow cellularity in beagles

    International Nuclear Information System (INIS)

    Wilson, F.D.; O'Grady, L.; Momeni, M.; Wheeling, J.A.; Klein, K.; Graham, R.; Jow, N.; Di Bartola, S.

    1975-01-01

    Data accumulated for the hematological effects program are reviewed. Particular emphasis is given to the effects of acute and chronic irradiation on hematopoietic progenitor populations (CFU-C, colony-forming units in culture) and ''candidate'' mesenchymal progenitors (PFU-C, plaque-forming units in culture) using methylcellulose bone marrow culture systems and both in vivo and in vitro radiation exposure protocols. Preliminary results of studies on the temporal effects of acute x-irradiation on the capacity of PFU-C to generate colony stimulating activity (CSA) are also presented. The results of such experiments are providing the basis upon which future RBE studies on a variety of nuclides will be structured. Data (including age related changes) is also presented on in vivo bone marrow cellularity determinations, as well as for marrow stem cell quantitative studies using nondestructive techniques for normal Beagles. In these studies, two techniques for correction of variable effects of hemodilution are compared. Such studies are also providing baseline data for the 60 Co hematological effects program

  2. CFU-C populations in blood and bone marrow of dogs after lethal irradiation and allogeneic transfusion with cryopreserved blood mononuclear cells

    International Nuclear Information System (INIS)

    Nothdurft, W.; Fliedner, T.M.; Calvo, W.; Flad, H.-D.; Huget, R.; Koerbling, M.; Krumbacher-von Loringen, K; Ross, W.M.; Schnappauf, H.-P.; Steinbach, I.

    1978-01-01

    Colony forming units in agar (CFU-C) were assayed in both bone marrow and peripheral blood of dogs during haemopoietic recovery after lethal total-body irradiation (1200 R) and allogeneic transfusion of blood mononuclear cells (MNC) from histocompatible donors. MNC had been collected from the peripheral blood by continuous-flow centrifugation leucapheris and cryopreserved at -196 deg C until transfusion. Two groups of dogs were studied. Group 1 dogs (n = 12) were given between 0.39 and 2.76 x 10 9 MNC per kg body wt. Group 2 dogs (n = 14) were transfused with a similar number of MNC, ranging from 0.51 to 1.87 x 10 9 per kg body wt., but in addition underwent immuno-suppressive therapy with methotrexate. In group 1 dogs, there was a rather good correlation between the number of CFU-C in the regenerating bone marrow and the recovery of the peripheral blood granulocyte values. The regeneration of the CPU-C population in the bone marrow of methotrexate-treated dogs showed a somewhat more heterogeneous picture than in dogs of group 1 and in dogs that, in a previous study, were transfused with autologous MNC. The minimum time interval required for the reconstitution of peripheral blood CFU-C to normal levels was 2-4 weeks but usually took from 4-14 weeks. (author)

  3. Studies on the regeneration of the CFU-C population in blood and bone marrow or lethally irradiated dogs after autologous transfusion of cryopreserved mononuclear blood cells

    International Nuclear Information System (INIS)

    Nothdurft, W.; Bruch, C.; Fliedner, T.M.; Rueber, E.

    1977-01-01

    In a group of 8 lethally irradiated (1200 R) dogs, that were transfused autologously with cryopreserved mononuclear cells (MNC) derived from the peripheral blood by leucapheresis the concentration of colony-forming units in agar (CFU-C) in bone marrow and peripheral blood was estimated at regular intervals after irradiation and transfusion of MNC. The numbers of MNC transfused per kg body weight ranged from 0.32 x 10 9 to 1.63 x 10 9 with an incidence of CFU-C between 0.02 x 10 5 and 1.38 x 10 5 . In 6 dogs the CFU-C levels in the bone marrow reached the normal preirradiation values between days 15 and 20. But in 2 dogs that had received the lowest CFU-C numbers the regeneration of the bone marrow CFU-C was markedly delayed. In general the time course of the bone marrow repopulation by CFU-C for single dogs was reflected by a corresponding regeneration pattern of the blood CFU-C. The time course of the curves for the blood CFU-C levels on the other hand was of the same kind as for the granulocyte values in the peripheral blood, that reached the normal levels mainly around day 30 and thereafter. Considerable fluctuations were seen in the blood CFU-C levels of single dogs before irradiation and after mononuclear leucocyte transfusion. Despite of such limitations the blood CFU-C content appeared to be a useful indicator of haematopoietic regeneration of the bone marrow. (author)

  4. A distinct population of clonogenic and multipotent murine follicular keratinocytes residing in the upper isthmus

    DEFF Research Database (Denmark)

    Jensen, Uffe Birk; Yan, Xiaohong; Triel, Charlotte

    2008-01-01

    lineages. We have identified a distinct population of murine hair follicle keratinocytes residing in the upper isthmus (UI) between the infundibulum and bulge regions that are distinguished by low alpha6 integrin levels and are negative for CD34 and Sca-1. Purified UI cells give rise to long-term, stable...

  5. Enumeration of haemopoietic progenitors (CFU-C and BFU-E) in liquid microculture using a limiting dilution analysis.

    Science.gov (United States)

    Marchal, G; Milon, G

    1980-01-01

    In order to overcome the difficulty of scoring multicentric colonies of haemopoietic progenitor cells, cultures in 10 microliter of liquid medium were grown. Plated at three different cell concentrations, progenitor cells (CFU-C or BFU-E) are not present in all wells. Their presence is easily scored in each well of microculture 7 days after incubation. A limiting dilution analysis allows one to obtain accurate quantification.

  6. Quantitative response of bone marrow colony-forming units (CFU-C and PFU-C) in weaning beagles exposed to acute whole-body γ irradiation

    International Nuclear Information System (INIS)

    Wilson, F.D.; Stitzel, K.A.; Klein, A.K.; Shifrine, M.; Graham, R.; Jones, M.; Bradley, E.; Rosenblatt, L.S.

    1978-01-01

    Using a methylcellulose-supported bone marrow culture system, the dose-response relationships of suspended granulocyte-monocyte colonies (CFU-C) and adherent fibroblastic colonies (PFU-C) were investigated in 2- to 3-month-old beagles exposed to acute whole-body γ irradiation. Groups of weanling beagles were exposed at a rate of 140 R/hr delivered from a 60 Co γ source achieving total exposures ranging from 0 to 586 R. Twenty-four hours following irradiation, bone marrow was collected, plated into methylcellulose, and after 1 week of incubation both colony types were quantitated. In addition, bone marrow cellularity determinations were made for a variety of bones using an 59 Fe-labeling technique. The results show a D 37 for the linear part of the slope of 70 R for CFU-C. Although within the limits of the experiment a D 37 could not be established for the fibroblastic populations, the results indicate a substantial degree of radioresistance for these elements supporting our previous studies on PFU-C, performed on mice, which suggested a D 37 of approximately 400 R for the progenitors of these fibroblastic elements

  7. Comparison of cell number, viability, phenotypic profile, clonogenic, and proliferative potential of adipose-derived stem cell populations between centrifuged and noncentrifuged fat.

    Science.gov (United States)

    Ibatici, Adalberto; Caviggioli, Fabio; Valeriano, Vinci; Quirici, Nadia; Sessarego, Nadia; Lisa, Andrea; Klinger, Francesco; Forcellini, Davide; Maione, Luca; Klinger, Marco

    2014-10-01

    Autologous fat grafting is a widely adopted surgical technique in both the reconstructive and aesthetic fields. This study aimed to compare centrifuged lipoaspirates harvested and refined by the Coleman technique with noncentrifuged lipoaspirates in terms of cell number and viability, phenotypic profile, and clonogenic and proliferative potential of adipose-derived stem cell (ADSC) populations. For each patient, both a centrifuged sample using the Coleman's technique and a noncentrifuged sample of adipose tissue were collected. Adipose-derived stem cells from both the centrifuged fraction (CF) and the noncentrifuged fraction (NCF) were isolated. The recovered ADSCs were used to set up flow cytometry analysis, colony-forming units-fibroblast (CFU-F) assays, and ADSC cultures. The number of recovered cells was variable among the different donors but significantly higher in the CF donors. Cell viability, determined by the Trypan Blue dye assay, always exceeded 95 %, in both the CF and NCF fractions. Analysis of the putative ADSC subpopulations showed a significant enrichment of the mesenchymal and endothelial progenitors in CF compared with NCF. No differences in the clonogenic efficiency of the ADSC samples were observed when the same number of cells were plated from each fraction. On the contrary, when equal fat volumes were compared, the colony-forming ability of CF was always significantly higher than that of its NCF counterparts. This is the first study to comprehensively characterize the impact of Coleman's technique on the quality of lipoaspirates, showing that centrifugation is safe and feasible and does not impair cell viability, can augment the content in ADSC and the frequency of CFU-F, and reduces the number of proinflammatory blood cells.

  8. Radiogenic neoplasia in thyroid and mammary clonogens

    International Nuclear Information System (INIS)

    Clifton, K.H.

    1991-01-01

    We have developed rat thyroid and mammary clonogen transplantation systems for the study of radiogenic cancer induction at the target cell level in vivo. The epithelial cell populations of both glands contain small subpopulations of cells which are capable of giving rise to monoclonal glandular structures when transplanted and stimulated with appropriate hormones. During the end of the last grant year and the first half of the current grant year, we have completed analyses and summarized for publication: investigations on the relationship between grafted thyroid cell number and the rapidity and degree of reestablishment of the thyroid-hypothalamicpituitary axis in thyroidectomized rats maintained on a normal diet or an iodine deficient diet; studies of the persistence of, and the differentiation potential and functional characteristics of, the TSH- (thyrotropin-) responsive sub-population of clonogens during goitrogenesis, the plateau-phase of goiter growth, and goiter involution; studies of changes in the size of the clonogen sub-population during goitrogenesis, goiter involution and the response to goitrogen rechallenge; and the results of the large carcinogenesis experiment on the nature of the grafted thyroid cell number-dependent suppression of promotion/progression to neoplasia in grafts of radiation-initiated thyroid cells. We are testing new techniques for the culture, cytofluorescent analysis and characterization mammary epithelial cells and of clonogens in a parallel project, and plan to apply similar technology to the thyroid epithelial cells and clonogen population. Data from these studies will be used in the design of future carcinogenesis experiments on neoplastic initiation by high and low LET radiations and on cells interactions during the neoplastic process

  9. Radiogenic neoplasia in thyroid and mammary clonogens

    International Nuclear Information System (INIS)

    Clifton, K.H.

    1992-01-01

    We have developed rat thyroid and mammary clonogen transplantation systems for the study of radiogenic cancer induction at the target cell level in vivo. The epithelial cell populations of both glands contain small subpopulations of cells which are capable of giving rise to monoclonal glandular structures when transplanted and stimulated with appropriate hormones. Previous results indicated that these clonogens are the precursor cells of radiogenic cancer, and that initiation, is common event at the clonegenic cell level. Detailed information on the physiologic control of clonogen proliferation, differentiation, and total numbers is thus essential to an understanding of the carcinogenic process. We report here studies on investigations on the relationships between grafted thyroid cell number and the rapidity and degree of reestablishment of the thyroid-hypothalamus-pituitary feedback axis in thyroidectomized rats maintained on a normal diet or an iodine deficient diet; studies of the persistence of, and the differentiation potential and functional characteristics of, the TSH-(thyrotropin-) responsive sub- population of clonogens during goitrogenesis, the plateau-phase of goiter growth, and goiter involution; studies of changes in the size of the clonogen sub-population during goitrogenesis, goiter involution and the response to goitrogen rechallenge; and a large carcinogenesis experiment on the nature of the grafted thyroid cell number-dependent suppression of promotion/progression to neoplasia in grafts of radiation-initiated thyroid cells. Data from these studies will be used in the design of future carcinogenesis experiments on neoplastic initiation by high and low LET radiations and on cell interactions during the neoplastic process

  10. Possible involvement of NO in the stimulating effect of pifithrins on survival of hemopoietic clonogenic cells.

    Science.gov (United States)

    Proskuryakov, S Ya; Konoplyannikov, A G; Konoplyannikova, O A; Shevchenko, L I; Verkhovskii, Yu G; Tsyb, A F

    2009-02-01

    Pifithrin alpha (PFTalpha), one of the first known low molecular weight modulators of activity of tumor suppressor p53, increases survival of hemopoietic clonogenic cells (evaluated by the criterion of formation of endogenous spleen CFU-C8 colonies in irradiated animals). This effect appeared when PFTalpha was administered either before or after irradiation. Increase in CFU-C8 was also observed after administration of two PFTalpha analogs, derivatives of 2-amino-4,5,6,7-tetrahydrobenzothiazole. These included a parent compound, 2-ATBT (2-amino-4,5,6,7-tetrahydrobenzothiazole), which is used for synthesis of PFTalpha, and a product of its intramolecular cyclization under physiological conditions, cyclo-PFT (2-(4-methylphenyl)imidazo[2,1-b]-5,6,7,8-tetrahydrobenzothiazole). Earlier we found that many low molecular weight compounds increasing number of CFU-C8 (e.g. isothiourea derivatives) demonstrate NO inhibitory activity. Such activity was also found in 2-ATBT and cyclo-PFT by means of EPR spectroscopy of NO. These compounds caused more than twofold inhibition of NO production in vivo. Thus, it has been demonstrated that PFTalpha and its structural analogs increase survival of hemopoietic clonogenic cells in vivo, and NO may play a role in the mechanism of this effect.

  11. Radiogenic neoplasia in thyroid and mammary clonogens

    International Nuclear Information System (INIS)

    Clifton, K.H.

    1993-01-01

    The induction of cancer by ionizing radiation is a matter of great practical importance to the nuclear industry, to national defense, to radiological medicine and to the general public. It is increasingly apparent that carcinogenesis is one of the leading dose-limiting effects of radiation exposure (Co90). Quantitative information at the cellular level is essential to an understanding of the mechanisms of radiogenic neoplastic initiation and the stages of promotion and progression to overt neoplasia. We have developed two experimental models, the rat thyroid and rat mammary clonogen transplant systems, for the quantitative study of radiation carcinogenesis at the cellular level in vivo (C185). The most important steps taken or completed during the current grant year include: (a) demonstration of the high age-dependent radiosensitivity of prepubertal rat mammary clonogens to radiogenic damage which may influence their susceptibility to neoplastic initiation, and (b) demonstration of the feasibility of using a molecular test for clonogenicity in which Simple Sequence Repeats in the DNA serve as identifying signals of the genotypic origin of the cells. We have also (c) set up a large carcinogenesis experiment to test the effect of close intercellular contact in thyroid glands in situ on promotion-progression of radiogenically initiated clonogens, (d) achieved considerable further concentration of thyroid clonogens, and (e) begun to explore whether thyroid cells can be induced to give rise to three dimensional multicellular structures in culture in reconstituted basement membrane. These are discussed in this report

  12. The proliferative status of intestinal epithelial clonogenic cells: sensitivity to S phase specific cytotoxic agents.

    Science.gov (United States)

    Boarder, T A; Blackett, N M

    1976-11-01

    High concentrations of tritiated thymidine and cytosine arabinoside (Ara-C) have been used to selectively kill cells in the crypts of Lieberkuhn that are synthesizing DNA. The effect of these agents on the number of regenerating microcolonies seen 3 1/2 days after a range of radiation doses indicates that a majority of the clonogenic cells are proliferating rapidly and that the slowly proliferating cells at the base of the crypt do not represent the whole clonogenic population.

  13. Correlation of proliferative and clonogenic tumor cells in multiple myeloma

    International Nuclear Information System (INIS)

    Karp, J.E.; Burke, P.J.; Saylor, P.L.; Humphrey, R.L.

    1984-01-01

    To expand on the findings from previous clinical trials that the growth of residual tumor is increased at a predictable time following initial drug administration, malignant plasma cells from bone marrows of patients with multiple myeloma (MM) were examined for changes in proliferation and clonogenicity induced in vivo by cyclophosphamide and in vitro by drug-induced humoral stimulatory activity. Peak plasma cell [ 3 H]thymidine labeling index (LI) occurred predictably following drug and paralleled changes in agar colony formation by marrow cells obtained during therapy. Colony-forming capacity of pretreatment MM marrow populations was enhanced when those cells were cultured with humoral stimulatory activity, similar to the increased colony formation detected in Day 9 postcyclophosphamide marrows at the time of peak plasma cell LI. To further define a relationship between proliferative plasma cells and colony-forming tumor cells, MM marrows were fractionated by sedimentation on an isokinetic gradient. Enrichment of a proliferative tumor cell cohort was achieved, evidenced by [ 3 H]thymidine LI. Colony-forming cells were also enriched by isokinetic gradient sedimentation, and agar colony formation by MM marrow cell fractions correlated with the kinetic characteristics of the isolated subpopulations. These studies of whole and fractionated human MM marrow cell populations suggest that the kinetically active cells which are induced to proliferate in vivo and in vitro are closely related to the clonogenic tumor cells which produce colonies in agar and which, like those cells measured by [ 3 H]thymidine LI, respond to growth stimulation by drug-induced humoral stimulatory activity

  14. An improved method for staining cell colonies in clonogenic assays

    OpenAIRE

    Guda, Kishore; Natale, Leanna; Markowitz, Sanford D.

    2007-01-01

    Clonogenic assay is a widely used experimental approach to test for the effects of drugs/genes on the growth and proliferative characteristics of cells in vitro. Accurate quantitation of treatment effects in clonogeneic assays depends on the ability to visualize and count cell colonies precisely. We report a novel method (referred as ETeB) for staining cell colonies grown on plastic and specially coated substrates like collagen. Using colon cancer cell lines grown on plastic and collagen, we ...

  15. Miniaturization of the Clonogenic Assay Using Confluence Measurement

    Directory of Open Access Journals (Sweden)

    Christian Mayr

    2018-03-01

    Full Text Available The clonogenic assay is a widely used method to study the ability of cells to ‘infinitely’ produce progeny and is, therefore, used as a tool in tumor biology to measure tumor-initiating capacity and stem cell status. However, the standard protocol of using 6-well plates has several disadvantages. By miniaturizing the assay to a 96-well microplate format, as well as by utilizing the confluence detection function of a multimode reader, we here describe a new and modified protocol that allows comprehensive experimental setups and a non-endpoint, label-free semi-automatic analysis. Comparison of bright field images with confluence images demonstrated robust and reproducible detection of clones by the confluence detection function. Moreover, time-resolved non-endpoint confluence measurement of the same well showed that semi-automatic analysis was suitable for determining the mean size and colony number. By treating cells with an inhibitor of clonogenic growth (PTC-209, we show that our modified protocol is suitable for comprehensive (broad concentration range, addition of technical replicates concentration- and time-resolved analysis of the effect of substances or treatments on clonogenic growth. In summary, this protocol represents a time- and cost-effective alternative to the commonly used 6-well protocol (with endpoint staining and also provides additional information about the kinetics of clonogenic growth.

  16. Hidden stressors in the clonogenic assay used in radiobiology experiments

    International Nuclear Information System (INIS)

    Potter, M.D.E.; Suchowerska, N.; Rizvi, S.; McKenzie, D.R.

    2011-01-01

    Full text: While clonogenic assays are extensively used in radiobiology, there is no widely accepted procedure for choosing the composition of the cell culture media. Cell line suppliers recommend a specific culture medium for each cell line, however a researcher will frequently customize this aspect of the protocol by supplementing the recommended support medium with additives. For example, many researchers add antibiotics, in order to avoid contamination of cells and the consequent loss of data, with little discussion of the influence of the antibiotics on the clonogenic survival of the cells. It is assumed that the effect of any variables in the growth medium on cell survival is taken into consideration by comparing the survival fraction relative to that of controls grown under the same conditions. In the search for better cancer treatment, the effect of various stressors on clonogenic cell survival is under investigation. This study seeks to identify and test potential stressors commonly introduced into the cell culture medium, which may confound the response to radiation. (author)

  17. An improved method for staining cell colonies in clonogenic assays.

    Science.gov (United States)

    Guda, Kishore; Natale, Leanna; Markowitz, Sanford D

    2007-06-01

    Clonogenic assay is a widely used experimental approach to test for the effects of drugs/genes on the growth and proliferative characteristics of cells in vitro. Accurate quantitation of treatment effects in clonogeneic assays depends on the ability to visualize and count cell colonies precisely. We report a novel method (referred as ETeB) for staining cell colonies grown on plastic and specially coated substrates like collagen. Using colon cancer cell lines grown on plastic and collagen, we compared the colony staining efficiencies of the widely used methylene blue, and Ethidium bromide (ETeB) stains. Results show that the ETeB protocol works well on plastic and is extremely effective for staining colonies on collagen when compared to methylene blue. The key features and advantages of ETeB technique are; (a) reduction in background for colonies grown on collagen and possibly other substrates, (b) the whole procedure takes less than a minute, (c) no post-stain washing step is required which eliminates colony losses for cell lines that are loosely adherent, (d) colony visualization and counting can be done immediately following the staining procedure using a standard UV illuminator and software, and (e) the method works across a wide variety of cell lines. The simplicity and robustness of this procedure should warrant its usage in both small and large-scale clonogenic experiments.

  18. Repair of potentially lethal damage in rat mammary clonogens following irradiation in organoid culture

    Energy Technology Data Exchange (ETDEWEB)

    Kamiya, K.; Kim, N.D.; Gould, M.N.; Clifton, K.H. (Wisconsin Univ., Madison, WI (USA). Dept. of Human Oncology)

    1991-05-01

    In the course of investigations of radiogenic neoplasia in mammary cells in vivo, post-irradiation repair of potentially lethal damage (PLDR) was previously observed in mammary epithelial clonogens when they were irradiated and left in their tissue environment for 4-24 h after exposure. In this study, a ten-fold increase in the concentration of mammary clonogens which could be assayed was achieved by the isolation and short term culture (2-4 days) of mammary organoids (ductal and end-bud fragments). Assays of clonogen concentrations were carried out with cell suspensions prepared immediately following irradiation of 4-day organoid cultures or 24 h after irradiation of such organoid cultures. A near four-fold increase in clonogen survival was observed with the delay in assay after irradiation; this is comparable to the PLDR seen in mammary clonogens irradiated and left in situ for 4-24 h after exposure. (author).

  19. Heterogeneity in cytokinetic, clonogenic, and radiation response induced by nutrient deprivation

    International Nuclear Information System (INIS)

    Grdina, D.J.; Williamson, K.D.; Johnson, T.S.; Sigdestad, C.P.

    1986-01-01

    A murine fibrosarcoma cell line (FSA 1233), with a capability to grow in vitro, was used to study biophysical heterogeneity induced by nutrient deprivation. Cell sub-populations were isolated by centrifuging cells through linear Renografin-density gradients. The effects of cell growth to late plateau phase on the cytokinetic, clonogenic, and radiation-survival characteristics were studied. It was observed that with increasing age of the cell culture, an increase in the proportion of relatively dense cells was associated with a decrease in plating efficiency. Cells collected at p=1.08 g/cm 3 have a plating efficiency of 0.2% compared with 0.01% for those isolated at p=1.16 g/cm 3 . Discrepancies were also seen between the tritiated thymidine labeling index (LI) and flow cytometry (FCM, % S phase) for cells collected throughout the gradient. The radiation sensitivities of selected cell populations isolated by density gradient centrifugation were determined and compared with data from a control plateau phase population. 15 refs., 4 figs., 1 tab

  20. Evolution of the clonogenic potential of human epidermal stem/progenitor cells with age

    Directory of Open Access Journals (Sweden)

    Zobiri O

    2012-02-01

    Full Text Available Olivia Zobiri, Nathalie Deshayes, Michelle Rathman-JosserandDepartment of Biological Research, L'Oréal Advanced Research, Clichy Cedex, FranceAbstract: A number of clinical observations have indicated that the regenerative potential and overall function of the epidermis is modified with age. The epidermis becomes thinner, repairs itself less efficiently after wounding, and presents modified barrier function recovery. In addition, the dermal papillae flatten out with increasing age, suggesting a modification in the interaction between epidermal and dermal compartments. As the epidermal regenerative capacity is dependent upon stem and progenitor cell function, it is naturally of interest to identify and understand age-related changes in these particular keratinocyte populations. Previous studies have indicated that the number of stem cells does not decrease with age in mouse models but little solid evidence is currently available concerning human skin. The objective of this study was to evaluate the clonogenic potential of keratinocyte populations isolated from the epidermis of over 50 human donors ranging from 18 to 71 years old. The data indicate that the number of epidermal cells presenting high regenerative potential does not dramatically decline with age in human skin. The authors believe that changes in the microenvironment controlling epidermal basal cell activity are more likely to explain the differences in epidermal function observed with increasing age.Keywords: skin, epidermal stem cells, aging, colony-forming efficiency test

  1. Radiogenic neoplasia in thyroid and mammary clonogens. Progress report, January 1, 1993--December 31, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Clifton, K.H.

    1993-07-30

    The induction of cancer by ionizing radiation is a matter of great practical importance to the nuclear industry, to national defense, to radiological medicine and to the general public. It is increasingly apparent that carcinogenesis is one of the leading dose-limiting effects of radiation exposure (Co90). Quantitative information at the cellular level is essential to an understanding of the mechanisms of radiogenic neoplastic initiation and the stages of promotion and progression to overt neoplasia. We have developed two experimental models, the rat thyroid and rat mammary clonogen transplant systems, for the quantitative study of radiation carcinogenesis at the cellular level in vivo (C185). The most important steps taken or completed during the current grant year include: (a) demonstration of the high age-dependent radiosensitivity of prepubertal rat mammary clonogens to radiogenic damage which may influence their susceptibility to neoplastic initiation, and (b) demonstration of the feasibility of using a molecular test for clonogenicity in which Simple Sequence Repeats in the DNA serve as identifying signals of the genotypic origin of the cells. We have also (c) set up a large carcinogenesis experiment to test the effect of close intercellular contact in thyroid glands in situ on promotion-progression of radiogenically initiated clonogens, (d) achieved considerable further concentration of thyroid clonogens, and (e) begun to explore whether thyroid cells can be induced to give rise to three dimensional multicellular structures in culture in reconstituted basement membrane. These are discussed in this report.

  2. Comparative radiosensitivity of clonogenic cells of inoculated Ehrlich ascites and solid tumors

    International Nuclear Information System (INIS)

    Konoplyannikov, A.G.; Kolesnikova, A.I.; Lepekhina, L.A.; Shtejn, L.V.

    1988-01-01

    Survival of clonogenic cells of solid Ehrlich ascited tumor (EAT) exposed to 60 Co-γ-radiation in vitro under the oxygenation conditions was investigated and the clonogenic capacity and radiosensitivity of these cells and cells of the previously studied EAT ascitic form and Lewis solid tumor comparatively studied to elucidate how the efficiency of colony formation (ECF) would affect their radiosensitivity. ECF for solid EAT cells was 2.6±0.3%, which was lower, by about an order of magnitude, than that for ascitic form of this tumor and was nearly the same as that for Luis tumor cells. A median cell lethal dose (D 0 ) was practically the same for all tumors under study. It is suggested that the differences in ECF do not substantially influence the radiosensitivity of clonogenic cells of the studied tumors

  3. Control of ductal vs. alveolar differentiation of mammary clonogens and susceptibility to radiation-induced mammary cancer

    Energy Technology Data Exchange (ETDEWEB)

    Kamiya, Kenji; Yokoro, Kenjiro (Hiroshima Univ. (Japan). Research Inst. for Nuclear Medicine and Biology); Clifton, K.H.; Gould, M.N.

    1991-12-01

    We have developed an in vitro-in vivo transplantation assay for measuring the concentration of clonogenic epithelial cells in cell suspensions of rat mammary tissue. Rat mammary clonogens from organoid cultures are capable of the same degree of PLDR as clonogens in vivo. The growth and differentiation of mammary clonogens to alveolar colonies or ductal colonies is regulated as follows: (a) in the presence of E{sub 2} and high prolactin (Prl), cortisol induces mammary clonogens to proliferate and differentiate to form alveolar colonies which secrete milk and begin losing clonogenic potential, (b) in cortisol deficient rats, Prl and E{sub 2} synergistically stimulate non-secretory ductal colonies, formation of which retain clonogenic potential, (c) E{sub 2} without progesterone stimulates alveolar colony formation in the presence of cortical and high Prl, (d) progesterone inhibits mammary clonogen differentiation to milk-producing cells and induces ductogenesis in a dose responsive fashion in the presence of E{sub 2}, cortisol and high Prl. High prolactin levels coupled with glucocorticoid deficiency increases the susceptibility to mammary carcinogenesis following low dose radiation exposure by increasing the number of total mammary clonogens which are the presumptive target cells and by stimulating their proliferation after exposure. (author).

  4. Control of ductal vs. alveolar differentiation of mammary clonogens and susceptibility to radiation-induced mammary cancer

    International Nuclear Information System (INIS)

    Kamiya, Kenji; Yokoro, Kenjiro; Clifton, K.H.; Gould, M.N.

    1991-01-01

    We have developed an in vitro-in vivo transplantation assay for measuring the concentration of clonogenic epithelial cells in cell suspensions of rat mammary tissue. Rat mammary clonogens from organoid cultures are capable of the same degree of PLDR as clonogens in vivo. The growth and differentiation of mammary clonogens to alveolar colonies or ductal colonies is regulated as follows: a) in the presence of E 2 and high prolactin (Prl), cortisol induces mammary clonogens to proliferate and differentiate to form alveolar colonies which secrete milk and begin losing clonogenic potential, b) in cortisol deficient rats, Prl and E 2 synergistically stimulate non-secretory ductal colonies, formation of which retain clonogenic potential, c) E 2 without progesterone stimulates alveolar colony formation in the presence of cortical and high Prl, d) progesterone inhibits mammary clonogen differentiation to milk-producing cells and induces ductogenesis in a dose responsive fashion in the presence of E 2 , cortisol and high Prl. High prolactin levels coupled with glucocorticoid deficiency increases the susceptibility to mammary carcinogenesis following low dose radiation exposure by increasing the number of total mammary clonogens which are the presumptive target cells and by stimulating their proliferation after exposure. (author)

  5. Breast cancer resistance protein identifies clonogenic keratinocytes in human interfollicular epidermis.

    Science.gov (United States)

    Ma, Dongrui; Chua, Alvin Wen Choong; Yang, Ennan; Teo, Peiyun; Ting, Yixin; Song, Colin; Lane, Ellen Birgitte; Lee, Seng Teik

    2015-03-24

    There is a practical need for the identification of robust cell-surface markers that can be used to enrich for living keratinocyte progenitor cells. Breast cancer resistance protein (ABCG2), a member of the ATP binding cassette (ABC) transporter family, is known to be a marker for stem/progenitor cells in many tissues and organs. We investigated the expression of ABCG2 protein in normal human epidermis to evaluate its potential as a cell surface marker for identifying and enriching for clonogenic epidermal keratinocytes outside the pilosebaceous tract. Immunofluorescence and immunoblotting studies of human skin showed that ABCG2 is expressed in a subset of basal layer cells in the epidermis. Flow cytometry analysis showed approximately 2-3% of keratinocytes in non-hair-bearing epidermis expressing ABCG2; this population also expresses p63, β1 and α6 integrins and keratin 14, but not CD34, CD71, C-kit or involucrin. The ABCG2-positive keratinocytes showed significantly higher colony forming efficiency when co-cultured with mouse 3T3 feeder cells, and more extensive long-term proliferation capacity in vitro, than did ABCG2-negative keratinocytes. Upon clonal analysis, most of the freshly isolated ABCG2-positive keratinocytes formed holoclones and were capable of generating a stratified differentiating epidermis in organotypic culture models. These data indicate that in skin, expression of the ABCG2 transporter is a characteristic of interfollicular keratinocyte progentior cells and suggest that ABCG2 may be useful for enriching keratinocyte stem cells in human interfollicular epidermis.

  6. Lineage-related cytotoxicity and clonogenic profile of 1,4-benzoquinone-exposed hematopoietic stem and progenitor cells

    Energy Technology Data Exchange (ETDEWEB)

    Chow, Paik Wah [Biomedical Science Programme, School of Diagnostic & Applied Health Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Abdul Muda Aziz, 50300 Kuala Lumpur, Wilayah Persekutuan (Malaysia); Toxicology Laboratory, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur (Malaysia); Abdul Hamid, Zariyantey, E-mail: zyantey@ukm.edu.my [Biomedical Science Programme, School of Diagnostic & Applied Health Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Abdul Muda Aziz, 50300 Kuala Lumpur, Wilayah Persekutuan (Malaysia); Toxicology Laboratory, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur (Malaysia); Chan, Kok Meng [Environmental Health and Industrial Safety Programme, School of Diagnostic & Applied Health Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Abdul Muda Aziz, 50300 Kuala Lumpur, Wilayah Persekutuan (Malaysia); Toxicology Laboratory, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur (Malaysia); Inayat-Hussain, Salmaan Hussain [Environmental Health and Industrial Safety Programme, School of Diagnostic & Applied Health Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Abdul Muda Aziz, 50300 Kuala Lumpur, Wilayah Persekutuan (Malaysia); Rajab, Nor Fadilah [Biomedical Science Programme, School of Diagnostic & Applied Health Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Abdul Muda Aziz, 50300 Kuala Lumpur, Wilayah Persekutuan (Malaysia); Toxicology Laboratory, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur (Malaysia)

    2015-04-01

    Hematopoietic stem cells (HSCs) and hematopoietic progenitor cells (HPCs) are sensitive targets for benzene-induced hematotoxicity and leukemogenesis. The impact of benzene exposure on the complex microenvironment of HSCs and HPCs remains elusive. This study aims to investigate the mechanism linking benzene exposure to targeting HSCs and HPCs using phenotypic and clonogenic analyses. Mouse bone marrow (BM) cells were exposed ex vivo to the benzene metabolite, 1,4-benzoquinone (1,4-BQ), for 24 h. Expression of cellular surface antigens for HSC (Sca-1), myeloid (Gr-1, CD11b), and lymphoid (CD45, CD3e) populations were confirmed by flow cytometry. The clonogenicity of cells was studied using the colony-forming unit (CFU) assay for multilineage (CFU-GM and CFU-GEMM) and single-lineage (CFU-E, BFU-E, CFU-G, and CFU-M) progenitors. 1,4-BQ demonstrated concentration-dependent cytotoxicity in mouse BM cells. The percentage of apoptotic cells increased (p < 0.05) following 1,4-BQ exposure. Exposure to 1,4-BQ showed no significant effect on CD3e{sup +} cells but reduced the total counts of Sca-1{sup +}, CD11b{sup +}, Gr-1{sup +}, and CD45{sup +} cells at 7 and 12 μM (p < 0.05). Furthermore, the CFU assay showed reduced (p < 0.05) clonogenicity in 1,4-BQ-treated cells. 1,4-BQ induced CFU-dependent cytotoxicity by significantly inhibiting colony growth for CFU-E, BFU-E, CFU-G, and CFU-M starting at a low concentration of exposure (5 μM); whereas for the CFU-GM and CFU-GEMM, the inhibition of colony growth was remarkable only at 7 and 12 μM of 1,4-BQ, respectively. Taken together, 1,4-BQ caused lineage-related cytotoxicity in mouse HPCs, demonstrating greater toxicity in single-lineage progenitors than in those of multi-lineage. - Highlights: • We examine 1,4-BQ toxicity targeting mouse hematopoietic cell lineages. • 1,4-BQ induces concentration-dependent cytotoxicity in bone marrow (BM) cells. • 1,4-BQ shows lineage-related toxicity on hematopoietic stem and

  7. Lineage-related cytotoxicity and clonogenic profile of 1,4-benzoquinone-exposed hematopoietic stem and progenitor cells

    International Nuclear Information System (INIS)

    Chow, Paik Wah; Abdul Hamid, Zariyantey; Chan, Kok Meng; Inayat-Hussain, Salmaan Hussain; Rajab, Nor Fadilah

    2015-01-01

    Hematopoietic stem cells (HSCs) and hematopoietic progenitor cells (HPCs) are sensitive targets for benzene-induced hematotoxicity and leukemogenesis. The impact of benzene exposure on the complex microenvironment of HSCs and HPCs remains elusive. This study aims to investigate the mechanism linking benzene exposure to targeting HSCs and HPCs using phenotypic and clonogenic analyses. Mouse bone marrow (BM) cells were exposed ex vivo to the benzene metabolite, 1,4-benzoquinone (1,4-BQ), for 24 h. Expression of cellular surface antigens for HSC (Sca-1), myeloid (Gr-1, CD11b), and lymphoid (CD45, CD3e) populations were confirmed by flow cytometry. The clonogenicity of cells was studied using the colony-forming unit (CFU) assay for multilineage (CFU-GM and CFU-GEMM) and single-lineage (CFU-E, BFU-E, CFU-G, and CFU-M) progenitors. 1,4-BQ demonstrated concentration-dependent cytotoxicity in mouse BM cells. The percentage of apoptotic cells increased (p < 0.05) following 1,4-BQ exposure. Exposure to 1,4-BQ showed no significant effect on CD3e + cells but reduced the total counts of Sca-1 + , CD11b + , Gr-1 + , and CD45 + cells at 7 and 12 μM (p < 0.05). Furthermore, the CFU assay showed reduced (p < 0.05) clonogenicity in 1,4-BQ-treated cells. 1,4-BQ induced CFU-dependent cytotoxicity by significantly inhibiting colony growth for CFU-E, BFU-E, CFU-G, and CFU-M starting at a low concentration of exposure (5 μM); whereas for the CFU-GM and CFU-GEMM, the inhibition of colony growth was remarkable only at 7 and 12 μM of 1,4-BQ, respectively. Taken together, 1,4-BQ caused lineage-related cytotoxicity in mouse HPCs, demonstrating greater toxicity in single-lineage progenitors than in those of multi-lineage. - Highlights: • We examine 1,4-BQ toxicity targeting mouse hematopoietic cell lineages. • 1,4-BQ induces concentration-dependent cytotoxicity in bone marrow (BM) cells. • 1,4-BQ shows lineage-related toxicity on hematopoietic stem and progenitors. • 1,4-BQ

  8. Elimination of clonogenic tumor cells from HL-60, Daudi, and U-937 cell lines by laser photoradiation therapy: implications for autologous bone marrow purging

    International Nuclear Information System (INIS)

    Gulliya, K.S.; Pervaiz, S.

    1989-01-01

    Laser photoradiation therapy was tested in an in vitro model for its efficacy in the elimination of non-Hodgkin's lymphoma cells. Results show that at 31.2 J/cm2 of laser light in the presence of 20 micrograms/mL of merocyanine 540 (MC540) there was greater than 5 log reduction in Burkitt's lymphoma (Daudi) cells. Similar tumor cell kill was obtained for leukemia (HL-60) cells at a laser light dose of 93.6 J/cm2. However, to obtain the same efficiency of killing for histiocytic lymphoma (U-937) cells, a higher dose of MC540 (25 micrograms/mL) was required. Clonogenic tumor stem cell colony formation was reduced by greater than 5 logs after laser photoradiation therapy. Under identical conditions for each cell line the percent survival for granulocyte-macrophage colony-forming units (CFU-GM, 45.9%, 40%, 17.5%), granulocyte/erythroid/macrophage/megakaryocyte (GEMM, 40.1%, 20.1%, 11.5%), colony-forming units (CFU-C, 16.2%, 9.1%, 1.8%), and erythroid burst-forming units (BFU-E, 33.4%, 17.8%, 3.9%) was significantly higher than the tumor cells. Mixing of gamma ray-irradiated normal marrow cells with tumor cells (1:1 and 10:1 ratio) did not interfere with the elimination of tumor cells. The effect of highly purified recombinant interferon alpha (rIFN) on laser photoradiation therapy of tumor cells was also investigated. In the presence of rIFN (30 to 3,000 U/mL), the viability of leukemic cells was observed to increase from 0% to 1.5% with a concurrent decrease in membrane polarization, suggesting an increase in fluidity of cell membrane in response to rIFN. However, at higher doses of rIFN (6,000 to 12,000 U/mL) this phenomenon was not observed. The viability of lymphoma cells remained unaffected at all doses of rIFN tested

  9. Upregulation of mitochondrial NAD+ levels impairs the clonogenicity of SSEA1+ glioblastoma tumor-initiating cells

    OpenAIRE

    Son, Myung Jin; Ryu, Jae-Sung; Kim, Jae Yun; Kwon, Youjeong; Chung, Kyung-Sook; Mun, Seon Ju; Cho, Yee Sook

    2017-01-01

    Emerging evidence has emphasized the importance of cancer therapies targeting an abnormal metabolic state of tumor-initiating cells (TICs) in which they retain stem cell-like phenotypes and nicotinamide adenine dinucleotide (NAD+) metabolism. However, the functional role of NAD+ metabolism in regulating the characteristics of TICs is not known. In this study, we provide evidence that the mitochondrial NAD+ levels affect the characteristics of glioma-driven SSEA1+ TICs, including clonogenic gr...

  10. Parthenolide reduces the frequency of ABCB5-positive cells and clonogenic capacity of melanoma cells from anchorage independent melanospheres

    Science.gov (United States)

    Czyz, Malgorzata; Koprowska, Kamila; Sztiller-Sikorska, Malgorzata

    2013-01-01

    Growing evidence suggests that the cancer stem cell phenotype in melanoma is dynamically regulated. Therefore, effective therapies have to target simultaneously bulk tumor cells and melanoma stem-like cells. The aim of the present study was to investigate the effects of parthenolide on heterogeneous cancer cell populations from anchorage-independent melanospheres. Cells derived from nodular melanoma specimens were grown under serum-free sphere-forming conditions. The effects of parthenolide on cellular viability, immunophenotype and self-renewing capacity were assessed with cells from dissociated melanospheres. Its penetration capacity was evaluated with intact melanospheres. In melanoma cells that survived treatment with parthenolide, a different immunophenotype than that in untreated control was found. The frequency of cells expressing the ABCB5 transporter was markedly reduced. Most importantly, melanoma cells that survived parthenolide treatment lost their self-renewing capacity. Significantly lower influence of drug on cellular viability and frequency of ABCB5-positive cells was observed in intact melanospheres. The potential clinical significance of our findings is based on the ability of parthenolide to affect both bulk and melanoma stem-like cells with clonogenic capacity and high expression of the ABCB5 transporter. Its low penetration capacity, however, may limit its action to easily accessible melanoma cells, either circulating in the blood or those in the vicinity to blood vessels within the tumor. Because of limited penetration capacity of parthenolide, this drug should be further explored as a part of multimodal therapies rather than as a stand-alone therapeutic agent. PMID:23192276

  11. A radiobiological comparison of human tumor soft-agar clonogenic assays.

    Science.gov (United States)

    West, C M; Sutherland, R M

    1986-06-15

    Radiation survival curves have been generated for 3 human tumor cell lines as a means of comparing and evaluating the validity of human tumor soft-agar clonogenic assays. The assays investigated were the Hamburger-Salmon, Courtenay-Mills, Courtenay-Mills plus additions, soft agar (no additions), and soft agar plus additions. The additions were formulated to supplement the media used in soft agar assays of primary ovarian and cervical carcinoma specimens. Supplementing the media with additions led to a 2- to 3-fold increase in PE of CaSki cells but had no effect on the PEs of ME180 and OWI cells. Radiation survival curves were similar in all assays for CaSki and OWI but differed for ME180 cells. For ME180 cells, the Courtenay-Mills and soft agar assays plus additions produced the most radioresistant curves (Do = 2.2 Gy); the cells were more responsive when assayed by the Hamburger-Salmon method (Do = 1.5 Gy), and the soft agar and Courtenay-Mills assays gave the most radiosensitive curves (Do = 1.2 Gy). These results demonstrate that the PE of human tumor cell lines may be increased with no effect on radiation survival; radiation survival may be altered without changes in PE and neither may be altered by applying modifications and supplements to existing clonogenic assays.

  12. In vitro clonogenic capacity of periodontal ligament fibroblasts cultured with Emdogain.

    Science.gov (United States)

    Ashkenazi, Malka; Shaked, Ilanit

    2006-02-01

    The aim of the present study was to evaluate the efficiency of Emdogain (EMD) in preserving the size of the periodontal ligament progenitor pool (clonogenic capacity) and in promoting their proliferation. Periodontal ligament fibroblasts (PDLF) were obtained from explants of young permanent healthy tooth. After initial outgrowth (10 days to 2 weeks following explantation), the culture medium of experimental flasks was replaced with medium supplemented with 100 microg ml(-1) EMD, whereas the other served as controls and were fed with regular medium. Following 5 weeks, the cells were washed (3x), harvested (trypsin + EDTA), and evaluated for their viability. Viable cells from each group were inoculated into six 96-well plates at a concentration of one viable cell per two wells and were allowed to grow for 5 weeks. The percentage of cells with clonogenic capacity was determined as the number of colonies formed/number of cells seeded x 100 in the experimental and control groups. Three degrees of dish area coverage were utilized: up to 25%, between 25% and 75% and higher than 75%. This experiment was repeated four times from four different donors. A total of 2328 cells were evaluated, half of which, were cultured with EMD. The mean percentage of cells (from all donors) who exhibited any clonogenic capacity in the presence of EMD was comparable with that of cells cultured in the absence of EMD: 26.6 +/- 14.3% when compared with 34.6 +/- 20.6% respectively (P = 0.186). Similarly, the percentage of clones that proliferated to cover up to 25% of the well area was comparable in the two groups 7.5 +/- 8.6 for EMD-treated clones and 7.1 +/- 7.8 for untreated clones (P = 0.674). The percentage of clones that proliferated to cover 25% up to 75% of the well area was greater EMD-treated clones as compared with the untreated cells: 8.1 +/- 6.7% vs 3.8 +/- 3%. However this difference was not statistically significant (P = 0.277). In contrast, the percentage of clones that covered

  13. Determination of cell survival after irradiation via clonogenic assay versus multiple MTT Assay - A comparative study

    International Nuclear Information System (INIS)

    Buch, Karl; Peters, Tanja; Nawroth, Thomas; Sänger, Markus; Schmidberger, Heinz; Langguth, Peter

    2012-01-01

    For studying proliferation and determination of survival of cancer cells after irradiation, the multiple MTT assay, based on the reduction of a yellow water soluble tetrazolium salt to a purple water insoluble formazan dye by living cells was modified from a single-point towards a proliferation assay. This assay can be performed with a large number of samples in short time using multi-well-plates, assays can be performed semi-automatically with a microplate reader. Survival, the calculated parameter in this assay, is determined mathematically. Exponential growth in both control and irradiated groups was proven as the underlying basis of the applicability of the multiple MTT assay. The equivalence to a clonogenic survival assay with its disadvantages such as time consumption was proven in two setups including plating of cells before and after irradiation. Three cell lines (A 549, LN 229 and F 98) were included in the experiment to study its principal and general applicability

  14. Applications of high-throughput clonogenic survival assays in high-LET particle microbeams

    Directory of Open Access Journals (Sweden)

    Antonios eGeorgantzoglou

    2016-01-01

    Full Text Available Charged particle therapy is increasingly becoming a valuable tool in cancer treatment, mainly due to the favorable interaction of particle radiation with matter. Its application is still limited due, in part, to lack of data regarding the radiosensitivity of certain cell lines to this radiation type, especially to high-LET particles. From the earliest days of radiation biology, the clonogenic survival assay has been used to provide radiation response data. This method produces reliable data but it is not optimized for high-throughput microbeam studies with high-LET radiation where high levels of cell killing lead to a very low probability of maintaining cells’ clonogenic potential. A new method, therefore, is proposed in this paper, which could potentially allow these experiments to be conducted in a high-throughput fashion. Cells are seeded in special polypropylene dishes and bright-field illumination provides cell visualization. Digital images are obtained and cell detection is applied based on corner detection, generating individual cell targets as x-y points. These points in the dish are then irradiated individually by a micron field size high-LET microbeam. Post-irradiation, time-lapse imaging follows cells’ response. All irradiated cells are tracked by linking trajectories in all time-frames, based on finding their nearest position. Cell divisions are detected based on cell appearance and individual cell temporary corner density. The number of divisions anticipated is low due to the high probability of cell killing from high-LET irradiation. Survival curves are produced based on cell’s capacity to divide at least 4-5 times. The process is repeated for a range of doses of radiation. Validation shows the efficiency of the proposed cell detection and tracking method in finding cell divisions.

  15. Applications of High-Throughput Clonogenic Survival Assays in High-LET Particle Microbeams.

    Science.gov (United States)

    Georgantzoglou, Antonios; Merchant, Michael J; Jeynes, Jonathan C G; Mayhead, Natalie; Punia, Natasha; Butler, Rachel E; Jena, Rajesh

    2015-01-01

    Charged particle therapy is increasingly becoming a valuable tool in cancer treatment, mainly due to the favorable interaction of particle radiation with matter. Its application is still limited due, in part, to lack of data regarding the radiosensitivity of certain cell lines to this radiation type, especially to high-linear energy transfer (LET) particles. From the earliest days of radiation biology, the clonogenic survival assay has been used to provide radiation response data. This method produces reliable data but it is not optimized for high-throughput microbeam studies with high-LET radiation where high levels of cell killing lead to a very low probability of maintaining cells' clonogenic potential. A new method, therefore, is proposed in this paper, which could potentially allow these experiments to be conducted in a high-throughput fashion. Cells are seeded in special polypropylene dishes and bright-field illumination provides cell visualization. Digital images are obtained and cell detection is applied based on corner detection, generating individual cell targets as x-y points. These points in the dish are then irradiated individually by a micron field size high-LET microbeam. Post-irradiation, time-lapse imaging follows cells' response. All irradiated cells are tracked by linking trajectories in all time-frames, based on finding their nearest position. Cell divisions are detected based on cell appearance and individual cell temporary corner density. The number of divisions anticipated is low due to the high probability of cell killing from high-LET irradiation. Survival curves are produced based on cell's capacity to divide at least four to five times. The process is repeated for a range of doses of radiation. Validation shows the efficiency of the proposed cell detection and tracking method in finding cell divisions.

  16. TRAIL causes deletions at the HPRT and TK1 loci of clonogenically competent cells

    Energy Technology Data Exchange (ETDEWEB)

    Miles, Mark A.; Shekhar, Tanmay M. [Department of Biochemistry and Genetics, La Trobe University, Bundoora, Victoria (Australia); La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria (Australia); Hall, Nathan E. [La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria (Australia); Life Sciences Computation Centre, Victorian Life Sciences Computation Initiative, Melbourne, Victoria (Australia); Hawkins, Christine J., E-mail: c.hawkins@latrobe.edu.au [Department of Biochemistry and Genetics, La Trobe University, Bundoora, Victoria (Australia); La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria (Australia)

    2016-05-15

    Highlights: • Treatment with TRAIL or EMS provokes mutations in clonogenically viable TK6 cells. • TRAIL is 2–5-fold less mutagenic than an equivalently lethal concentration of EMS. • EMS mainly causes transition mutations at the HPRT and TK1 loci of TK6 cells. • Most loss-of-function HPRT or TK1 mutations caused by TRAIL treatment are deletions. - Abstract: When chemotherapy and radiotherapy are effective, they function by inducing DNA damage in cancerous cells, which respond by undergoing apoptosis. Some adverse effects can result from collateral destruction of non-cancerous cells, via the same mechanism. Therapy-related cancers, a particularly serious adverse effect of anti-cancer treatments, develop due to oncogenic mutations created in non-cancerous cells by the DNA damaging therapies used to eliminate the original cancer. Physiologically achievable concentrations of direct apoptosis inducing anti-cancer drugs that target Bcl-2 and IAP proteins possess negligible mutagenic activity, however death receptor agonists like TRAIL/Apo2L can provoke mutations in surviving cells, probably via caspase-mediated activation of the nuclease CAD. In this study we compared the types of mutations sustained in the HPRT and TK1 loci of clonogenically competent cells following treatment with TRAIL or the alkylating agent ethyl methanesulfonate (EMS). As expected, the loss-of-function mutations in the HPRT or TK1 loci triggered by exposure to EMS were almost all transitions. In contrast, only a minority of the mutations identified in TRAIL-treated clones lacking HPRT or TK1 activity were substitutions. Almost three quarters of the TRAIL-induced mutations were partial or complete deletions of the HPRT or TK1 genes, consistent with sub-lethal TRAIL treatment provoking double strand breaks, which may be mis-repaired by non-homologous end joining (NHEJ). Mis-repair of double-strand breaks following exposure to chemotherapy drugs has been implicated in the pathogenesis of

  17. Assessment of Radiation-Equivalency of Favorite Foods Based on Apoptotic and Clonogenic Cell Death

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seunghee; Park, Hyosung; Lee, Minho; Kim, Eunhee [Seoul National Univ., Seoul (Korea, Republic of)

    2013-05-15

    In this study, the cytotoxicity of favorite foods was investigated to provide chemical doses causing bio-effects comparable with those by radiation exposure. Extracts from alcohol, cigarette and coffee have been investigated for their cytotoxicity in terms of apoptosis induction and clonogenic cell killing. The comparison of familiar favorite food items with radiation in cellular toxicity might help the public have balanced judgment on the severity of radiation exposure. Future study pursues estimating dose-rate effect and the investigation will be continued with other cell lines. People fear that ionizing radiation, despite of its usefulness, bears significant risk factor. In particular, after Fukushima nuclear accident in March of 2011, people become over-sensitive to radiation exposure and nuclear power. Such fear by the public of nuclear power inevitably costs the nuclear industry a high expense for safety measures, not to mention brings the public uneasy life. It is important that the consequence of radiation exposure is conveyed to the public in a friendly way with actual data.

  18. Assessment of Radiation-Equivalency of Favorite Foods Based on Apoptotic and Clonogenic Cell Death

    International Nuclear Information System (INIS)

    Lee, Seunghee; Park, Hyosung; Lee, Minho; Kim, Eunhee

    2013-01-01

    In this study, the cytotoxicity of favorite foods was investigated to provide chemical doses causing bio-effects comparable with those by radiation exposure. Extracts from alcohol, cigarette and coffee have been investigated for their cytotoxicity in terms of apoptosis induction and clonogenic cell killing. The comparison of familiar favorite food items with radiation in cellular toxicity might help the public have balanced judgment on the severity of radiation exposure. Future study pursues estimating dose-rate effect and the investigation will be continued with other cell lines. People fear that ionizing radiation, despite of its usefulness, bears significant risk factor. In particular, after Fukushima nuclear accident in March of 2011, people become over-sensitive to radiation exposure and nuclear power. Such fear by the public of nuclear power inevitably costs the nuclear industry a high expense for safety measures, not to mention brings the public uneasy life. It is important that the consequence of radiation exposure is conveyed to the public in a friendly way with actual data

  19. The chalcone butein from Rhus verniciflua Stokes inhibits clonogenic growth of human breast cancer cells co-cultured with fibroblasts

    Directory of Open Access Journals (Sweden)

    Tan Jenny

    2005-03-01

    Full Text Available Abstract Background Butein (3,4,2',4'-tetrahydroxychalone, a plant polyphenol, is a major biologically active component of the stems of Rhus verniciflua Stokes. It has long been used as a food additive in Korea and as an herbal medicine throughout Asia. Recently, butein has been shown to suppress the functions of fibroblasts. Because fibroblasts are believed to play an important role in promoting the growth of breast cancer cells, we investigated the ability of butein to inhibit the clonogenic growth of small numbers of breast cancer cells co-cultured with fibroblasts in vitro. Methods We first measured the clonogenic growth of small numbers of the UACC-812 human breast cancer cell line co-cultured on monolayers of serum-activated, human fibroblasts in the presence of butein (2 μg/mL or various other modulators of fibroblast function (troglitazone-1 μg/mL; GW9662-1 μM; meloxican-1 μM; and 3,4 dehydroproline-10 μg/mL. In a subsequent experiment, we measured the dose-response effect on the clonogenic growth of UACC-812 breast cancer cells by pre-incubating the fibroblasts with varying concentrations of butein (10 μg/ml-1.25 μg/mL. Finally, we measured the clonogenic growth of primary breast cancer cells obtained from 5 clinical specimens with normal fibroblasts and with fibroblasts that had been pre-treated with a fixed dose of butein (2.5 μg/mL. Results Of the five modulators of fibroblast function that we tested, butein was by far the most potent inhibitor of clonogenic growth of UACC-812 breast cancer cells co-cultured with fibroblasts. Pre-treatment of fibroblasts with concentrations of butein as low as 2.5 μg/mL nearly abolished subsequent clonogenic growth of UACC-812 breast cancer cells co-cultured with the fibroblasts. A similar dose of butein had no effect on the clonogenic growth of breast cancer cells cultured in the absence of fibroblasts. Significantly, clonogenic growth of the primary breast cancer cells was also

  20. Effect of ultrasound sonication on clonogenic survival and mitochondria of ovarian cancer cells in the presence of methylene blue.

    Science.gov (United States)

    Xiang, Junyan; Leung, Albert Wingnang; Xu, Chuanshan

    2014-10-01

    This study aimed to investigate the effect of ultrasound sonication in the presence of methylene blue on clonogenic survival and mitochondria of ovarian cancer cells. Human ovarian cancer HO-8910 cells, which were incubated with different concentrations of methylene blue for 1 hour, were exposed to an ultrasonic wave for 5 seconds with intensity of 0.46 W/cm(2). Clonogenic survival of HO-8910 cells after ultrasound sonication was measured by a colony-forming unit assay. Mitochondrial structural changes were observed on transmission electron microscopy, and the mitochondrial membrane potential was evaluated by confocal laser-scanning microscopy with rhodamine 123 staining. The colony-forming units of HO-8910 cells decreased considerably after ultrasound sonication in the presence of methylene blue. Transmission electron microscopy showed slightly enlarged mitochondria in the ultrasound-treated cells in the absence of methylene blue; however, seriously damaged mitochondria, even with almost complete disappearance of cristae, were found in the cells treated by ultrasound sonication in the presence of methylene blue. The mitochondrial membrane potential collapsed significantly when HO-8910 cells were treated by ultrasound sonication in the presence of methylene blue (P methylene blue markedly damaged mitochondrial structure and function and decreased clonogenic survival of HO-8910 cells. © 2014 by the American Institute of Ultrasound in Medicine.

  1. The phosphatidylinositol-3 kinase pathway is not essential for insulin-like growth factor I receptor-mediated clonogenic radioresistance

    International Nuclear Information System (INIS)

    Yu, Dong; Watanabe, Hiroshi; Shibuya, Hitoshi; Miura, Masahiko

    2002-01-01

    The insulin-like growth factor I receptor (IGF-IR) is known to induce clonogenic radioresistance in cells following ionizing irradiation. To explore the downstream signaling pathways, we focused on the phosphatidylinositol-3 kinase (PI3-K) pathway, which is thought to be the primary cell survival signal originating from the receptor. For this purpose, R- cells deficient in the endogenous IGF-IR were used as a recipient of the human IGF-IR with or without mutations at potential PI3-K activation sites: NPXY 950 and Y 1316 XXM. Mutats with double mutation at Y950/Y1316 exhibited not abrogated, but reduced activation of insulin receptor substance-1 (IRS-1), PI3-K, and Akt upon IGF-I stimulation. However, the mutants had the same clonogenic radioresistance as cells with wild type (WT) receptors. Neither wortmannin nor LY294002, specific inhibitors of PI3-K, affected the radioresistance of cells with WT receptors at concentrations specific for PI3-K. Collectively, these results indicate that the PI3-K pathway is not essential for IGF-IR-mediated clonogenic radioresistance. (author)

  2. Can cell survival parameters be deduced from non-clonogenic assays of radiation damage to normal tissue

    International Nuclear Information System (INIS)

    Michalowski, A.; Wheldon, T.E.; Kirk, J.

    1984-01-01

    The relationship between dose-response curves for large scale radiation injury to tissues and survival curves for clonogenic cells is not necessarily simple. Sterilization of clonogenic cells occurs near-instantaneously compared with the protracted lag period for gross injury to tissues. Moreover, with some types of macroscopic damage, the shapes of the dose-response curves may depend on time of assay. Changes in the area or volume of irradiated tissue may also influence the shapes of these curves. The temporal pattern of expression of large scale injury also varies between tissues, and two distinct groups can be recognized. In rapidly proliferating tissues, lag period is almost independent of dose, whilst in slowly proliferating tissues, it is inversely proportional to dose. This might be explained by invoking differences in corresponding proliferative structures of the tissues. (Three compartmental Type H versus one compartmental Type F proliferative organization). For the second group of tissues particularly, mathematical modelling suggests a systematic dissociation of the dose-response curves for clonogenic cell survival and large scale injury. In particular, it may be difficult to disentangle the contributions made to inter-fraction sparing by cellular repair processes and by proliferation-related factors. (U.K.)

  3. Age-Dependent Decline in Mouse Lung Regeneration with Loss of Lung Fibroblast Clonogenicity and Increased Myofibroblastic Differentiation

    Science.gov (United States)

    Paxson, Julia A.; Gruntman, Alisha; Parkin, Christopher D.; Mazan, Melissa R.; Davis, Airiel; Ingenito, Edward P.; Hoffman, Andrew M.

    2011-01-01

    While aging leads to a reduction in the capacity for regeneration after pneumonectomy (PNX) in most mammals, this biological phenomenon has not been characterized over the lifetime of mice. We measured the age-specific (3, 9, 24 month) effects of PNX on physiology, morphometry, cell proliferation and apoptosis, global gene expression, and lung fibroblast phenotype and clonogenicity in female C57BL6 mice. The data show that only 3 month old mice were fully capable of restoring lung volumes by day 7 and total alveolar surface area by 21 days. By 9 months, the rate of regeneration was slower (with incomplete regeneration by 21 days), and by 24 months there was no regrowth 21 days post-PNX. The early decline in regeneration rate was not associated with changes in alveolar epithelial cell type II (AECII) proliferation or apoptosis rate. However, significant apoptosis and lack of cell proliferation was evident after PNX in both total cells and AECII cells in 24 mo mice. Analysis of gene expression at several time points (1, 3 and 7 days) post-PNX in 9 versus 3 month mice was consistent with a myofibroblast signature (increased Tnc, Lox1, Col3A1, Eln and Tnfrsf12a) and more alpha smooth muscle actin (αSMA) positive myofibroblasts were present after PNX in 9 month than 3 month mice. Isolated lung fibroblasts showed a significant age-dependent loss of clonogenicity. Moreover, lung fibroblasts isolated from 9 and 17 month mice exhibited higher αSMA, Col3A1, Fn1 and S100A expression, and lower expression of the survival gene Mdk consistent with terminal differentiation. These data show that concomitant loss of clonogenicity and progressive myofibroblastic differentiation contributes to the age-dependent decline in the rate of lung regeneration. PMID:21912590

  4. Age-dependent decline in mouse lung regeneration with loss of lung fibroblast clonogenicity and increased myofibroblastic differentiation.

    Directory of Open Access Journals (Sweden)

    Julia A Paxson

    Full Text Available While aging leads to a reduction in the capacity for regeneration after pneumonectomy (PNX in most mammals, this biological phenomenon has not been characterized over the lifetime of mice. We measured the age-specific (3, 9, 24 month effects of PNX on physiology, morphometry, cell proliferation and apoptosis, global gene expression, and lung fibroblast phenotype and clonogenicity in female C57BL6 mice. The data show that only 3 month old mice were fully capable of restoring lung volumes by day 7 and total alveolar surface area by 21 days. By 9 months, the rate of regeneration was slower (with incomplete regeneration by 21 days, and by 24 months there was no regrowth 21 days post-PNX. The early decline in regeneration rate was not associated with changes in alveolar epithelial cell type II (AECII proliferation or apoptosis rate. However, significant apoptosis and lack of cell proliferation was evident after PNX in both total cells and AECII cells in 24 mo mice. Analysis of gene expression at several time points (1, 3 and 7 days post-PNX in 9 versus 3 month mice was consistent with a myofibroblast signature (increased Tnc, Lox1, Col3A1, Eln and Tnfrsf12a and more alpha smooth muscle actin (αSMA positive myofibroblasts were present after PNX in 9 month than 3 month mice. Isolated lung fibroblasts showed a significant age-dependent loss of clonogenicity. Moreover, lung fibroblasts isolated from 9 and 17 month mice exhibited higher αSMA, Col3A1, Fn1 and S100A expression, and lower expression of the survival gene Mdk consistent with terminal differentiation. These data show that concomitant loss of clonogenicity and progressive myofibroblastic differentiation contributes to the age-dependent decline in the rate of lung regeneration.

  5. Clonogenic growth of human breast cancer cells co-cultured in direct contact with serum-activated fibroblasts

    International Nuclear Information System (INIS)

    Samoszuk, Michael; Tan, Jenny; Chorn, Guillaume

    2005-01-01

    Accumulating evidence suggests that fibroblasts play a pivotal role in promoting the growth of breast cancer cells. The objective of the present study was to characterize and validate an in vitro model of the interaction between small numbers of human breast cancer cells and human fibroblasts. We measured the clonogenic growth of small numbers of human breast cancer cells co-cultured in direct contact with serum-activated, normal human fibroblasts. Using DNA microarrays, we also characterized the gene expression profile of the serum-activated fibroblasts. In order to validate the in vivo relevance of our experiments, we then analyzed clinical samples of metastatic breast cancer for the presence of myofibroblasts expressing α-smooth muscle actin. Clonogenic growth of human breast cancer cells obtained directly from in situ and invasive tumors was dramatically and consistently enhanced when the tumor cells were co-cultured in direct contact with serum-activated fibroblasts. This effect was abolished when the cells were co-cultured in transwells separated by permeable inserts. The fibroblasts in our experimental model exhibited a gene expression signature characteristic of 'serum response' (i.e. myofibroblasts). Immunostaining of human samples of metastatic breast cancer tissue confirmed that myofibroblasts are in direct contact with breast cancer cells. Serum-activated fibroblasts promote the clonogenic growth of human breast cancer cells in vitro through a mechanism that involves direct physical contact between the cells. This model shares many important molecular and phenotypic similarities with the fibroblasts that are naturally found in breast cancers

  6. Kinetics of mammary clonogenic cells and rat mammary cancer induction by X-rays or fission neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Kamiya, Kenji [Hiroshima Univ. (Japan). Research Inst. for Radiation Biology and Medicine; Higgins, P.D.; Tanner, M.A.; Gould, M.N.; Clifton, K.H.

    1999-12-01

    Following the hormonal treatment of rats with high prolactin levels and glucocorticoid deficiency (Prl+/Glc-) for 48 days (Day +48), total recoverable mammary DNA was increased by more than sevenfold, tritiated thymidine uptake by nearly fourfold, and total mammary clonogens by about fivefold. Irradiation with 4, 40, and 80 cGy X-rays on Day +48 increased total mammary carcinomas per rat-day-at-risk linearly with dose, and 40 and 80 cGy significantly decreased first carcinoma latency. A dose of 40 cGy X-rays before hormone treatment (Day -1) yielded tumor latencies and frequencies insignificantly different from unirradiated controls but significantly different from those when the dose was given on Day +48. Total carcinomas per rat-day-at-risk were fitted better by a function of dose to the power 0.4 than by a linear function after exposure to 1, 10. and 20 cGy fission neutrons, and 10 and 20 cGy significantly shortened the time to appearance of the first cancer. In contrast to results with X-rays, 10 cGy neutrons on Day -1 yielded tumor frequencies and latencies insignificantly different from 10 cGy neutrons on Day +48. The carcinogenic action of X-rays, but not of neutrons, was thus influenced by total clonogen numbers and/or proliferation rates. (author)

  7. No supra-additive effects of goserelin and radiotherapy on clonogenic survival of prostate carcinoma cells in vitro

    Directory of Open Access Journals (Sweden)

    Thelen Paul

    2007-08-01

    Full Text Available Abstract Background Oncological results of radiotherapy for locally advanced prostate cancer (PC are significantly improved by simultaneous application of LHRH analoga (e.g. goserelin. As 85% of PC express LHRH receptors, we investigated the interaction of goserelin incubation with radiotherapy under androgen-deprived conditions in vitro. Methods LNCaP and PC-3 cells were stained for LHRH receptors. Downstream the LHRH receptor, changes in protein expression of c-fos, phosphorylated p38 and phosphorylated ERK1/2 were analyzed by means of Western blotting after incubation with goserelin and irradiation with 4 Gy. Both cell lines were incubated with different concentrations of goserelin in hormone-free medium. 12 h later cells were irradiated (0 – 4 Gy and after 12 h goserelin was withdrawn. Endpoints were clonogenic survival and cell viability (12 h, 36 h and 60 h after irradiation. Results Both tested cell lines expressed LHRH-receptors. Changes in protein expression demonstrated the functional activity of goserelin in the tested cell lines. Neither in LNCaP nor in PC-3 any significant effects of additional goserelin incubation on clonogenic survival or cell viability for all tested concentrations in comparison to radiation alone were seen. Conclusion The clinically observed increase in tumor control after combination of goserelin with radiotherapy in PC cannot be attributed to an increase in radiosensitivity of PC cells by goserelin in vitro.

  8. Impact of flattening-filter-free radiation on the clonogenic survival of astrocytic cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Steenken, Caroline; Fleckenstein, Jens; Kegel, Stefan; Jahnke, Lennart; Simeonova, Anna; Hartmann, Linda; Kuebler, Jens; Veldwijk, Marlon R.; Wenz, Frederik; Herskind, Carsten; Giordano, Frank Anton [Universitaetsmedizin Mannheim (UMM), Medical Faculty Mannheim, Heidelberg University, Department of Radiation Oncology, Mannheim (Germany)

    2015-07-15

    Flattening-filter-free (FFF) beams are increasingly used in radiotherapy as delivery times can be substantially reduced. However, the relative biologic effectiveness (RBE) of FFF may be increased relative to conventional flattened (FLAT) beams due to differences in energy spectra. Therefore, we investigated the effects of FFF and FLAT beams on the clonogenic survival of astrocytoma cells. Three cell lines (U251, U251-MGMT, and U87) were irradiated with 6-MV and 10-MV X-rays from a linear accelerator in FFF- or FLAT-beam modes at dose rates in the range of 0.5-24 Gy/min. The surviving fraction (SF) as function of dose (2-12 Gy) was determined by the colony formation assay and fitted by the linear-quadratic model. For both beams (FFF or FLAT), the cells were pelleted in conical 15-ml centrifuge tubes and irradiated at 2-cm depth in a 1 x 1-cm{sup 2} area on the central axis of a 30 x 30-cm{sup 2} field. Dosimetry was performed with a 0.3-cm{sup 3} rigid ionization chamber. RBE was determined for FFF versus FLAT irradiation. The RBE of FFF at 7.3-11.3 Gy was 1.027 ± 0.013 and 1.063 ± 0.018 relative to FLAT beams for 6- and 10-MV beams, respectively, and was only significantly higher than 1 for 10 MV. Significantly increased survival rates were seen for lower dose rates (0.5 Gy/min FLAT vs. 5 Gy/min FLAT) at higher doses (11.9 Gy), while no differences were seen at dose rates ≥ 1.4 Gy/min (1.4 Gy/min FFF vs. 14 Gy/min FFF and 2.4 Gy/min FFF vs. 24 Gy/min FFF). FFF beams showed only a slightly increased RBE relative to FLAT beams in this experimental set-up, which is unlikely to result in clinically relevant differences in outcome. (orig.) [German] Die Flattening-Filter-freie (FFF) Bestrahlungstechnik findet zunehmend Verwendung, da sich die Applikationsdauer der einzelnen Fraktionen deutlich verkuerzen laesst. Aufgrund der Unterschiede im Spektrum koennte die relative biologische Wirksamkeit (RBW) von FFF jedoch hoeher sein als bei konventioneller Technik (d.h. bei

  9. Adult Mouse Liver Contains Two Distinct Populations of Cholangiocytes

    Directory of Open Access Journals (Sweden)

    Bin Li

    2017-08-01

    Full Text Available The biliary system plays an important role in several acquired and genetic disorders of the liver. We have previously shown that biliary duct epithelium contains cells giving rise to proliferative Lgr5+ organoids in vitro. However, it remained unknown whether all biliary cells or only a specific subset had this clonogenic activity. The cell surface protease ST14 was identified as a positive marker for the clonogenic subset of cholangiocytes and was used to separate clonogenic and non-clonogenic duct cells by fluorescence-activated cell sorting. Only ST14hi duct cells had the ability to generate organoids that could be serially passaged. The gene expression profiles of clonogenic and non-clonogenic duct cells were similar, but several hundred genes were differentially expressed. RNA fluorescence in situ hybridization showed that clonogenic duct cells are interspersed among regular biliary epithelium at a ∼1:3 ratio. We conclude that adult murine cholangiocytes can be subdivided into two populations differing in their proliferative capacity.

  10. Clonogenic cell line survival of a human liver cancer cell line SMMC-7721 after carbon ion irradiation with different LET

    International Nuclear Information System (INIS)

    Lei Suwen; Su Xu; Wang Jifang; Li Wenjian

    2003-01-01

    Objective: To investigate the survival fraction of a human liver cancer cell line SMMC-7721 following irradiation with carbon ions with different LET. Methods: cells of the human liver cancer cell line SMMC-7721 were irradiated with carbon ions (LET=30 and 70 keV/μm). The survival fraction was determined with clonogenic assay after 9 days incubation in a 5% CO 2 incubator at 37 degree C. Results: When the survival fractions of 70 keV/μm were D s = 0.1 and D s=0.01 absorption dose were 2.94 and 5.88 Gy respectively, and those of 30 keV/μm were 4.00 and 8.00 Gy respectively. Conclusion: For the SMMC-7721 cell line, 70 keV/μm is more effective for cell killing than 30 keV/μm

  11. Effect of X-irradiation of clonogenic HeLa cells on the genome mutation frequencies in their progenies

    Energy Technology Data Exchange (ETDEWEB)

    Kucheryabaya, N.A.; Zavol' naya, E.S.; Khrust, Yu.R.; Vakhtin, Yu.B. (AN SSSR, Leningrad. Inst. Tsitologii; Moskovskij Gosudarstvennyj Univ. (USSR). Biologo-Pochvennyj Fakul' tet)

    1980-01-01

    Irradiation of clonogenic Hela cells with 100-350 R doses results in the increase of general frequency of genome mutations from (20.7+-0.4)x10/sup -2/ up to (24.8+-0.4)x10/sup -2/-(31.9+-0.3)x10/sup -2/ on a cell per a generation. The increase occurs mainly at the expense of hyperploid mutants, whereas frequency of appearance of cells with reduced number of chromosomes (hypoploids) does not change reliably. For Hela culture, used in experiments, a very high heterogeneity of cells on DNA content in interfase nuclei and a very high level of spontaneous frequency of genome mutation are characteristical, that should be taken into account during the analysis of obtained results.

  12. Significance of hypoxia for tumor response to radiation: Mathematical modeling and analysis of local control and clonogenic assay data

    International Nuclear Information System (INIS)

    Buffa, Francesca Meteora

    2002-01-01

    Various hypotheses for radiation local tumor control probability (ltcp) were modeled, and assessed against local tumor control (LTC) and clonogenic assay (CA) data. For head-and-neck tumors receiving low-LET external-beam irradiation, the best model was a Poisson ltcp accounting for cell repopulation, hypoxia, and tumor volume dependence of radiosensitivity (α). This confirmed that hypoxia is limiting LTC of these tumors, with the magnitude depending upon tumor volume. However, LTC of cervical carcinoma receiving external-beam irradiation and brachytherapy was well described by a model not accounting for hypoxia. Furthermore, when the survival fraction at 2 Gy (SF 2 ) and colony forming efficiency (CFE) measured for individual patients were incorporated into this model, very good correlation with LTC was seen (p=0.0004). After multivariate analysis, this model was the best independent prognostic factor for LTC and patient survival. Furthermore, no difference in prediction was seen when a model based on birth-and-death stochastic theory was used. Two forms of hypoxia are known to be present in tumors: diffusion-limited, chronic hypoxia (CH), and acute, transient hypoxia (TH). A modeling study on WiDr multicellular spheroids showed that the CH effect on LTC is significantly lower than expected from CA. This could arise from energy charge depletion accompanying CH, reducing the number of proliferating clonogenic cells that can repair radiation damage, and thus mitigating the radioresistance of CH cells. This suggests that TH, rather than CH, may be the limiting factor for in vivo LTC. Finally, by computing ltcp using Monte Carlo calculated dose distributions, it was shown that Monte Carlo statistical noise can cause an underestimation of ltcp, with the magnitude depending upon the model hypotheses

  13. Preservation of differentiation and clonogenic potential of human hematopoietic stem and progenitor cells during lyophilization and ambient storage.

    Directory of Open Access Journals (Sweden)

    Sandhya S Buchanan

    2010-09-01

    Full Text Available Progenitor cell therapies show great promise, but their potential for clinical applications requires improved storage and transportation. Desiccated cells stored at ambient temperature would provide economic and practical advantages over approaches employing cell freezing and subzero temperature storage. The objectives of this study were to assess a method for loading the stabilizing sugar, trehalose, into hematopoietic stem and progenitor cells (HPC and to evaluate the effects of subsequent freeze-drying and storage at ambient temperature on differentiation and clonogenic potential. HPC were isolated from human umbilical cord blood and loaded with trehalose using an endogenous cell surface receptor, termed P2Z. Solution containing trehalose-loaded HPC was placed into vials, which were transferred to a tray freeze-dryer and removed during each step of the freeze-drying process to assess differentiation and clonogenic potential. Control groups for these experiments were freshly isolated HPC. Control cells formed 1450+/-230 CFU-GM, 430+/-140 BFU-E, and 50+/-40 CFU-GEMM per 50 microL. Compared to the values for the control cells, there was no statistical difference observed for cells removed at the end of the freezing step or at the end of primary drying. There was a gradual decrease in the number of CFU-GM and BFU-E for cells removed at different temperatures during secondary drying; however, there were no significant differences in the number of CFU-GEMM. To determine storage stability of lyophilized HPC, cells were stored for 4 weeks at 25 degrees C in the dark. Cells reconstituted immediately after lyophilization produced 580+/-90 CFU-GM ( approximately 40%, relative to unprocessed controls p<0.0001, 170+/-70 BFU-E (approximately 40%, p<0.0001, and 41+/-22 CFU-GEMM (approximately 82%, p = 0.4171, and cells reconstituted after 28 days at room temperature produced 513+/-170 CFU-GM (approximately 35%, relative to unprocessed controls, p<0

  14. Rapid alternative to the clonogenic assay for measuring antibody and complement-mediated killing of tumor cells

    International Nuclear Information System (INIS)

    Gee, A.P.; Rolfe, A.E.; Worthington-White, D.; Graham-Pole, J.; Boyle, M.D.

    1985-01-01

    A study of the methods used to quantitate killing of tumor cells by antibody and complement has highlighted a number of problems. Using leukemia as a model, the authors have found that the release of 51 Cr from labeled tumor cells treated with antibody and complement can be an equivocal measure of cell viability. Combined with its restricted sensitivity (less than a 2 log range of cell killing) this makes this widely used assay of questionable value for detecting small numbers of viable cells, or for identifying subpopulations of complement-resistant cells. As an alternative a [ 125 I]iododeoxyuridine uptake assay has been developed, that combines the simplicity and rapidity of the 51 Cr release technique with the sensitivity of a clonogenic assay. This method eliminates the problem of spontaneous isotope release, inherent in prelabeling assays, and variability from experiment to experiment can be avoided by including a viable cell standard curve within each assay. The sensitivity of the 125 IUdR uptake method, which can be completed within a day, is similar to that of a 10 day methylcellulose cloning assay and was capable of detecting the presence of a minor subpopulation of complement-resistant tumor cells

  15. Reactivation of HIC-1 gene by saRNA inhibits clonogenicity and invasiveness in breast cancer cells.

    Science.gov (United States)

    Zhao, Feng; Pan, Shengli; Gu, Yan; Guo, Shanyu; Dai, Qiancheng; Yu, Yingyan; Zhang, Wei

    2015-01-01

    Hypermethylated in cancer 1 (HIC-1) is a tumor suppressor gene, which is epigenetically silenced in breast cancer. It is known that the loss of HIC-1, caused by promoter hypermethylation, is associated with tumor aggression and poor survival in breast carcinoma. It has been shown that small activating RNA (saRNA) targeting promoter sequences may induce gene re-expression. In the current study, saRNA was used to restore HIC-1 expression, and the effects on colony formation, invasiveness and the cell cycle in breast cancer cells were explored. dsHIC1-2998, an saRNA, exhibited activating efficacy on MCF-7 and MDA-MB-231 cancer cell lines. A clonogenicity assay showed that evident colony inhibition was induced via saRNA-mediated re-expression of HIC-1 in the two cancer cell lines. Reactivation of HIC-1 significantly inhibited cell migration and invasion, resulting in G0/G1 cell cycle arrest in these cell lines. These findings suggest that HIC-1 may be a potential target in gene therapy for the treatment of breast cancer. saRNA may function as a therapeutic option for upregulating tumor suppressor genes in breast cancer.

  16. Mitochondrial-Targeted Decyl-Triphenylphosphonium Enhances 2-Deoxy-D-Glucose Mediated Oxidative Stress and Clonogenic Killing of Multiple Myeloma Cells.

    Directory of Open Access Journals (Sweden)

    Jeanine Schibler

    Full Text Available Therapeutic advances have markedly prolonged overall survival in multiple myeloma (MM but the disease currently remains incurable. In a panel of MM cell lines (MM.1S, OPM-2, H929, and U266, using CD138 immunophenotyping, side population staining, and stem cell-related gene expression, we demonstrate the presence of stem-like tumor cells. Hypoxic culture conditions further increased CD138low stem-like cells with upregulated expression of OCT4 and NANOG. Compared to MM cells, these stem-like cells maintained lower steady-state pro-oxidant levels with increased uptake of the fluorescent deoxyglucose analog. In primary human MM samples, increased glycolytic gene expression correlated with poorer overall and event-free survival outcomes. Notably, stem-like cells showed increased mitochondrial mass, rhodamine 123 accumulation, and orthodox mitochondrial configuration while more condensed mitochondria were noted in the CD138high cells. Glycolytic inhibitor 2-deoxyglucose (2-DG induced ER stress as detected by qPCR (BiP, ATF4 and immunoblotting (BiP, CHOP and increased dihydroethidium probe oxidation both CD138low and CD138high cells. Treatment with a mitochondrial-targeting agent decyl-triphenylphosphonium (10-TPP increased intracellular steady-state pro-oxidant levels in stem-like and mature MM cells. Furthermore, 10-TPP mediated increases in mitochondrial oxidant production were suppressed by ectopic expression of manganese superoxide dismutase. Relative to 2-DG or 10-TPP alone, 2-DG plus 10-TPP combination showed increased caspase 3 activation in MM cells with minimal toxicity to the normal hematopoietic progenitor cells. Notably, treatment with polyethylene glycol conjugated catalase significantly reduced 2-DG and/or 10-TPP-induced apoptosis of MM cells. Also, the combination of 2-DG with 10-TPP decreased clonogenic survival of MM cells. Taken together, this study provides a novel strategy of metabolic oxidative stress-induced cytotoxicity of MM

  17. Clonogenic, myogenic progenitors expressing MCAM/CD146 are incorporated as adventitial reticular cells in the microvascular compartment of human post-natal skeletal muscle.

    Directory of Open Access Journals (Sweden)

    Tiziana Persichini

    Full Text Available Recent observation identifies subendothelial (mural cells expressing MCAM, a specific system of clonogenic, self-renewing, osteoprogenitors (a.k.a, "mesenchymal stem cells" in the microvascular compartment of post-natal human bone marrow (BM. In this study, we used MCAM/CD146, as a marker to localize, isolate and assay subendothelial clonogenic cells from the microvasculature of postnatal human skeletal muscle. We show here that these cells share with their BM counterpart, anatomic position (subendothelial/adventitial and ex vivo clonogenicity (CFU-Fs. When assayed under the stringent conditions, these cells display a high spontaneous myogenic potential (independent of co-culture with myoblasts or of in vivo fusion with local myoblasts, which is otherwise only attained in cultures of satellite cells. These muscle-derived mural cells activated a myogenic program in culture. Cultured CD146+ cells expressed the myogenic factors (Pax7, Pax3 and Myf5, NCAM/CD56, desmin as well as proteins characteristic of more advanced myogenic differentiation, such as myosin heavy chain. In vivo, these cells spontaneously generate myotubes and myofibrils. These data identify the anatomy and phenotype of a novel class of committed myogenic progenitor in human post-natal skeletal muscle of subendothelial cells associated with the abluminal surface of microvascular compartment distinct from satellite cells.

  18. The effect of the non-ionic surfactant Brij 30 on the cytotoxicity of adriamycin in monolayer, spheroid and clonogenic culture systems.

    Science.gov (United States)

    Kerr, D J; Wheldon, T E; Russell, J G; Maurer, H R; Florence, A T; Halbert, G W; Freshney, R I; Kaye, S B

    1987-09-01

    The effects of a non-ionic polyoxyethylated lauryl ether surfactant (Brij 30) on monolayer uptake and spheroid penetration of adriamycin have been studied. Co-incubation of adriamycin with Brij 30 increases intracellular adriamycin levels by 2-3-fold. Although, in the concentrations used, Brij 30 alone is not cytotoxic, adriamycin and Brij 30 mixtures are significantly more cytotoxic (monolayer ID90 = 0.6 microgram/ml; disaggregated spheroid ID50 = 1.9 micrograms/ml) and induce significantly longer spheroid growth delay than adriamycin alone (monolayer ID90 = 2.1 micrograms/ml; disaggregated spheroid ID50 = 3.3 micrograms/ml). Adriamycin is equally cytotoxic to mouse normal granulocytes and chronic myeloid leukaemic (M1 cell line) cells in agar clonogenic cultures. The addition of Brij 30 appears to enhance preferentially the activity of adriamycin against these tumour cells relative to the normal granulocytes.

  19. The cytotoxic activity of cisplatin, carboplatin and teniposide alone and combined determined on four human small cell lung cancer cell lines by the clonogenic assay

    DEFF Research Database (Denmark)

    Roed, H; Vindeløv, L L; Christensen, I J

    1988-01-01

    Using the clonogenic assay to compare the cytotoxic activity of cisplatin and carboplatin on four human small cell lung cancer cell lines, cisplatin was shown to be equally or more potent than carboplatin at equitoxic doses with 1 h incubation. Increased potency of carboplatin was revealed when...... the drugs were tested with continuous incubation, although cisplatin still was the most potent drug when compared on a microgram to microgram basis. This relative increase in potency of carboplatin can at least partly be explained by the development of a more reactive form of the drug when stored in tissue...... culture medium. By combining either cisplatin or carboplatin with teniposide additive cell kill was obtained. Additivity was also obtained when cisplatin was combined with carboplatin. Since the two drugs have a different toxicity pattern a clinical synergy may be obtained by combined use of these two...

  20. The fundamental prevalence of chronic myeloid leukemia-generating clonogenic cells in the light of the neutrality theory of evolution.

    Science.gov (United States)

    Jankovic, G M; Pavlovic, M; Vukomanovic, D J; Colovic, M D; Lazarevic, V

    2001-01-01

    A variety of normal human tissues have been reported to harbor small cell populations carrying potentially oncogenic gene rearrangements. This backdrop of mutant cells may be present in the majority of healthy individuals and is apparently weakly selected against. This may provide empirical support for the concept of global neutrality, or near-neutrality (very weak selection), of many somatic mutations. Many healthy individuals, as well as patients with chronic myeloid leukemia, manifest the BCR-ABL fusion gene in blood cells. The presumed neutrality of the BCR-ABL rearrangement-carrying pluripotential hematopoietic stem cells and the relative uniformity of the incidence rate of CML worldwide were used to estimate the extent of the background of BCR-ABL-positive stem cells and the numerical size of the human pluripotential hematopoietic stem cell pool. Three different approaches (molecular-epidemiological, statistical, and population genetical) were employed. Each resulted in very similar estimates of the size of the stem cells carrying the BCR-ABL allele fusions (1.4 x 10(4) cells) and the size of the total human stem cell pool (1.6 x 10(9) cells per individual). The implication of these estimates in the context of the hierarchical nature of the stem cell pool is also considered. The presumptive smaller-sized population of CD34(-) stem cells could not be characterized by any of the approaches used as a "founding" population, representing an ultimate source of all hematopoietic progenitors, or as a subset of stem cells comprising a deeper "kinetic" segment of the total (10(9)-sized) stem cell compartment. (c)2001 Elsevier Science.

  1. Population.

    Science.gov (United States)

    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,…

  2. Natural Killer Cells Improve Hematopoietic Stem Cell Engraftment by Increasing Stem Cell Clonogenicity In Vitro and in a Humanized Mouse Model.

    Science.gov (United States)

    Escobedo-Cousin, Michelle; Jackson, Nicola; Laza-Briviesca, Raquel; Ariza-McNaughton, Linda; Luevano, Martha; Derniame, Sophie; Querol, Sergio; Blundell, Michael; Thrasher, Adrian; Soria, Bernat; Cooper, Nichola; Bonnet, Dominique; Madrigal, Alejandro; Saudemont, Aurore

    2015-01-01

    Cord blood (CB) is increasingly used as a source of hematopoietic stem cells (HSC) for transplantation. Low incidence and severity of graft-versus-host disease (GvHD) and a robust graft-versus-leukemia (GvL) effect are observed following CB transplantation (CBT). However, its main disadvantages are a limited number of HSC per unit, delayed immune reconstitution and a higher incidence of infection. Unmanipulated grafts contain accessory cells that may facilitate HSC engraftment. Therefore, the effects of accessory cells, particularly natural killer (NK) cells, on human CB HSC (CBSC) functions were assessed in vitro and in vivo. CBSC cultured with autologous CB NK cells showed higher levels of CXCR4 expression, a higher migration index and a higher number of colony forming units (CFU) after short-term and long-term cultures. We found that CBSC secreted CXCL9 following interaction with CB NK cells. In addition, recombinant CXCL9 increased CBSC clonogenicity, recapitulating the effect observed of CB NK cells on CBSC. Moreover, the co-infusion of CBSC with CB NK cells led to a higher level of CBSC engraftment in NSG mouse model. The results presented in this work offer the basis for an alternative approach to enhance HSC engraftment that could improve the outcome of CBT.

  3. Down-regulation of 5-HT1B and 5-HT1D receptors inhibits proliferation, clonogenicity and invasion of human pancreatic cancer cells.

    Directory of Open Access Journals (Sweden)

    Nilgun Gurbuz

    Full Text Available Pancreatic ductal adenocarcinoma is characterized by extensive local tumor invasion, metastasis and early systemic dissemination. The vast majority of pancreatic cancer (PaCa patients already have metastatic complications at the time of diagnosis, and the death rate of this lethal type of cancer has increased over the past decades. Thus, efforts at identifying novel molecularly targeted therapies are priorities. Recent studies have suggested that serotonin (5-HT contributes to the tumor growth in a variety of cancers including prostate, colon, bladder and liver cancer. However, there is lack of evidence about the impact of 5-HT receptors on promoting pancreatic cancer. Having considered the role of 5-HT-1 receptors, especially 5-HT1B and 5-HT1D subtypes in different types of malignancies, the aim of this study was to investigate the role of 5-HT1B and 5-HT1D receptors in PaCa growth and progression and analyze their potential as cytotoxic targets. We found that knockdown of 5-HT1B and 5-HT1D receptors expression, using specific small interfering RNA (siRNA, induced significant inhibition of proliferation and clonogenicity of PaCa cells. Also, it significantly suppressed PaCa cells invasion and reduced the activity of uPAR/MMP-2 signaling and Integrin/Src/Fak-mediated signaling, as integral tumor cell pathways associated with invasion, migration, adhesion, and proliferation. Moreover, targeting 5-HT1B and 5-HT1D receptors down-regulates zinc finger ZEB1 and Snail proteins, the hallmarks transcription factors regulating epithelial-mesenchymal transition (EMT, concomitantly with up-regulating of claudin-1 and E-Cadherin. In conclusion, our data suggests that 5-HT1B- and 5-HT1D-mediated signaling play an important role in the regulation of the proliferative and invasive phenotype of PaCa. It also highlights the therapeutic potential of targeting of 5-HT1B/1D receptors in the treatment of PaCa, and opens a new avenue for biomarkers identification

  4. Early LC3 lipidation induced by d-limonene does not rely on mTOR inhibition, ERK activation and ROS production and it is associated with reduced clonogenic capacity of SH-SY5Y neuroblastoma cells.

    Science.gov (United States)

    Berliocchi, Laura; Chiappini, Carlotta; Adornetto, Annagrazia; Gentile, Debora; Cerri, Silvia; Russo, Rossella; Bagetta, Giacinto; Corasaniti, Maria Tiziana

    2018-02-01

    d-Limonene is a natural monoterpene abundant in Citrus essential oils. It is endowed with several biological activities, including inhibition of carcinogenesis and promotion of tumour regression. Recently, d-limonene has been shown to modulate autophagic markers in vitro at concentrations found in vivo, in clinical pharmacokinetic studies. Autophagy is an intracellular catabolic process serving as both an adaptive metabolic response and a quality control mechanism. Because autophagy defects have been linked to a wide range of human pathologies, including neurodegeneration and cancer, there is a need for new pharmacological tools to control deregulated autophagy. To better understand the effects of d-limonene on autophagy, to identify the molecular mechanisms through which this monoterpene rapidly triggers LC3 lipidation and to evaluate the role for autophagy in long-term effects of d-limonene. Human SH-SY5Y neuroblastoma, HepG2 hepatocellular carcinoma and MCF7 breast cancer cells were used. Endogenous LC3-II levels were evaluated by western blotting. Autophagic flux assay was performed using bafilomycin A1 and chloroquine. Intracellular distribution of LC3 protein was studied by confocal microscopy analysis of LC3B-GFP transduced cells. Expression of lysosomal-membrane protein LAMP-1 was assessed by immunofluorescence analysis. Phosphorylated levels of downstream substrates of mTOR kinase (p70S6 kinase, 4E-BP1, and ULK1) and ERK were analyzed by western blotting. Production of reactive oxygen species (ROS) was assessed by live confocal microscopy of cells loaded with CellROX ® Green Reagent. Clonogenic assay was used to evaluate the ability of treated cells to proliferate and form colonies. LC3 lipidation promoted by d-limonene correlates with autophagosome formation and stimulation of basal autophagy. LC3 lipidation does not rely on inhibition of mTOR kinase, which instead appears to be transiently activated. In addition, d-limonene rapidly activates ERK and

  5. Auto-SCT induces a phenotypic shift from CMP to GMP progenitors, reduces clonogenic potential and enhances in vitro and in vivo cycling activity defined by (18)F-FLT PET scanning.

    Science.gov (United States)

    Woolthuis, C; Agool, A; Olthof, S; Slart, R H J A; Huls, G; Smid, W M; Schuringa, J J; Vellenga, E

    2011-01-01

    Autologous SCT (auto-SCT) introduces a reduced tolerance to chemotherapy even in patients with adequate engraftment, suggesting long-term effects of the transplantation procedure on the BM capacity. To study the hematopoietic cell compartment after auto-SCT, CD34(+) BM cells (n = 16) from patients at 6-9 months after auto-SCT were studied with regard to the progenitor subsets, colony frequency and cell cycle status. The BM compartments were studied in vivo using PET tracer 3-fluoro-3-deoxy-L-thymidine (¹⁸F-FLT PET). BM CD34(+) cells after auto-SCT were compared with normal CD34(+) cells and showed a phenotypic shift from common myeloid progenitor (CMP mean percentage 3.7 vs 19.4%, P=0.001) to granulocyte-macrophage progenitor (GMP mean percentage 51.8 vs 27.6%, P=0.01). In addition, a reduced clonogenic potential and higher cycling activity especially of the GMP fraction (41% ± 4 in G2/S phase vs 19% ± 2, P = 0.03) were observed in BM after auto-SCT compared with normal. The enhanced cycling activity was confirmed in vivo by showing a significantly higher uptake of the ¹⁸F-FLT PET tracer by the BM compartment. This study shows that auto-SCT results in defects of the hematopoietic compartment at least 6 months after auto-SCT, characterized by changes in the composition of progenitor subsets and enhanced in vitro and in vivo cycling activity.

  6. The human placenta is a hematopoietic organ during the embryonic and fetal periods of development.

    Science.gov (United States)

    Bárcena, Alicia; Kapidzic, Mirhan; Muench, Marcus O; Gormley, Matthew; Scott, Marvin A; Weier, Jingly F; Ferlatte, Christy; Fisher, Susan J

    2009-03-01

    We studied the potential role of the human placenta as a hematopoietic organ during embryonic and fetal development. Placental samples contained two cell populations-CD34(++)CD45(low) and CD34(+)CD45(low)-that were found in chorionic villi and in the chorioamniotic membrane. CD34(++)CD45(low) cells express many cell surface antigens found on multipotent primitive hematopoietic progenitors and hematopoietic stem cells. CD34(++)CD45(low) cells contained colony-forming units culture (CFU-C) with myeloid and erythroid potential in clonogenic in vitro assays, and they generated CD56(+) natural killer cells and CD19(+)CD20(+)sIgM(+) B cells in polyclonal liquid cultures. CD34(+)CD45(low) cells mostly comprised erythroid- and myeloid-committed progenitors, while CD34(-) cells lacked CFU-C. The placenta-derived precursors were fetal in origin, as demonstrated by FISH using repeat-sequence chromosome-specific probes for X and Y. The number of CD34(++)CD45(low) cells increased with gestational age, but their density (cells per gram of tissue) peaked at 5-8 wk, decreasing more than sevenfold at the onset of the fetal phase (9 wk of gestation). In addition to multipotent progenitors, the placenta contained myeloid- and erythroid-committed progenitors indicative of active in situ hematopoiesis. These data suggest that the human placenta is an important hematopoietic organ, raising the possibility of banking placental hematopoietic stem cells along with cord blood for transplantation.

  7. The effects of graded doses of 1 MeV fission neutrons or X-rays on the murine hematopoietic stroma

    International Nuclear Information System (INIS)

    Meijne, E.I.M.; Huiskamp, R.; Ploemacher, R.E.; Vos, O.

    1991-10-01

    The acute radiosensitivity in-vivo of the murine hematopoietic stroma for 1 MeV fission neutrons or 300 kVp X-rays was determined. Two different assays were used: 1) and in vitro clonogenic assay for fibro-blast precursor cells (CFU-F) and 2) subcutaneous grafting of femora or spleens. The number of stem cells (CFU-S) or precursor cells (CFU-C), which repopulated the subcutaneous implants, was used to measure the ability of the stroma to support hemopoiesis. The CFU-F were the most radiosensitive and the survival curves after neutron and X-irradiation were characterized by D 0 values of 0.75 and 2.45 Gy, respectively. For regeneration of CFU-S and CFU-C in sub-cutaneous implanted femora D 0 values of 0.92 and 0.84 Gy after neutron and 2.78 and 2.61 Gy after X-irradiation were found. The regeneration of CFU-S and CFU-C in sub-cutaneous implanted spleens was highly radioresistant as evidenced by D 0 values of 2.29 and 1.49 Gy for survival curves obtained after neutron irradiation, and D 0 values of 6.34 and 4.85 Gy after X-irradiation. The fission neutron RBE for all the cell populations was close to 3 and varied from 2.77 to 3.28, indicating that stromal cells are relatively more sensitive to neutron irradiation than hemopoietic cells. ((author). 38 refs.; 5 figs.; 2 tabs

  8. Population Ethics

    OpenAIRE

    BLACKORBY, Charles; BOSSERT, Walter; DONALDSON, David

    2006-01-01

    This paper reviews the welfarist approach to population ethics. We provide an overview of the critical-level utilitarian population principles and their generalized counterparts, examine important properties of these principles and discuss their relationships to other variable-population social-evaluation rules. We illustrate the difficulties arising in population ethics by means of an impossibility result and present characterizations of the critical-level generalized-utilitarian principles ...

  9. Population Research.

    Science.gov (United States)

    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…

  10. Population Education.

    Science.gov (United States)

    Shashidhar, B.; And Others

    Population education has assumed enormous importance in the national and international arena, since population changes influence the quality of life of individuals, families, the nation and the world as a whole. Population education has, however, special significance to India since young persons below the age of 15 are reported to form about 42%…

  11. Epigenetics targeted protein-vorinostat nanomedicine inducing apoptosis in heterogeneous population of primary acute myeloid leukemia cells including refractory and relapsed cases.

    Science.gov (United States)

    Chandran, Parwathy; Kavalakatt, Anu; Malarvizhi, Giridharan Loghanathan; Vasanthakumari, Divya Rani Vikraman Nair; Retnakumari, Archana Payickattu; Sidharthan, Neeraj; Pavithran, Keechilat; Nair, Shantikumar; Koyakutty, Manzoor

    2014-05-01

    Aberrant epigenetics play a key role in the onset and progression of acute myeloid leukemia (AML). Herein we report in silico modelling based development of a novel, protein-vorinostat nanomedicine exhibiting selective and superior anti-leukemic activity against heterogeneous population of AML patient samples (n=9), including refractory and relapsed cases, and three representative cell lines expressing CD34(+)/CD38(-) stem cell phenotype (KG-1a), promyelocytic phenotype (HL-60) and FLT3-ITD mutation (MV4-11). Nano-vorinostat having ~100nm size exhibited enhanced cellular uptake rendering significantly lower IC50 in AML cell lines and patient samples, and induced enhanced HDAC inhibition, oxidative injury, cell cycle arrest and apoptosis compared to free vorinostat. Most importantly, nanomedicine showed exceptional single-agent activity against the clonogenic proliferative capability of bone marrow derived leukemic progenitors, while remaining non-toxic to healthy bone marrow cells. Collectively, this epigenetics targeted nanomedicine appears to be a promising therapeutic strategy against various French-American-British (FAB) classes of AML. Through the use of a protein-vorinostat agent, exceptional single-agent activity was demonstrated against the clonogenic proliferative capability of bone marrow derived leukemic progenitors, while remaining non-toxic to healthy bone marrow cells. The studied epigenetics targeted nanomedicine approach is a promising therapeutic strategy against various French-American-British classes of acute myeloid leukemia. © 2014 Elsevier Inc. All rights reserved.

  12. [Population education].

    Science.gov (United States)

    1977-01-01

    Goal of population education is to raise knowledge and comprehension of causes and consequences, either personal or social, of excessive population growth. These days it is possible to plan the growth and evolution of the population to reach a level of balance and harmony between number of inhabitants of a country, and the country's natural resoruces. general objectives of population education are: 1) knowledge of basic demographic processes; 2) knowledge of effects of evolution and growth of population on social and economic life inside the family and inside society; 3) family size as related to nutrition, health, education, and job; and, 4) knowledge of population dynamics which the individual can influence through personal behavior, i.e. age at marriage, and spacing and number of children.

  13. Imaginary populations

    OpenAIRE

    Martínez-Abraín, Alejandro

    2010-01-01

    A few years ago, Camus & Lima (2002) wrote an essay to stimulate ecologists to think about how we define and use a fundamental concept in ecology: the population. They concluded, concurring with Berryman (2002), that a population is "a group of individuals of the same species that live together in an area of sufficient size to permit normal dispersal and/or migration behaviour and in which population changes are largely the results of birth and death processes". They pointed out that ecologis...

  14. Population Blocks.

    Science.gov (United States)

    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…

  15. Population crises and population cycles.

    Science.gov (United States)

    Russell, C; Russell, W M

    2000-01-01

    To prevent a population irretrievably depleting its resources, mammals have evolved a behavioural and physiological response to population crisis. When a mammalian population becomes dangerously dense, there is a reversal of behaviour. Co-operation and parental behaviour are replaced by competition, dominance and aggressive violence, leading to high mortality, especially of females and young, and a reduced population. The stress of overpopulation and the resulting violence impairs both the immune and the reproductive systems. Hence epidemics complete the crash of the population, and reproduction is slowed for three or four generations, giving the resources ample time to recover. In some mammal species, crisis and crisis response recur regularly, leading to cycles of population growth and relapse, oscillating about a fixed mean. Population crisis response and population cycles have been equally prominent in the history of human societies. But in man successive advances in food production have made possible growing populations, though with every such advance population soon outgrew resources again. Hence human cycles have been superimposed on a rising curve, producing a saw-tooth graph. Because advances in food production amounted to sudden disturbances in the relations between human populations and their environments, the crisis response in man has failed to avert famine and resource damage. In the large human societies evolved since the coming of settled agriculture and cities, the basic effects of violence, epidemics, famine and resource damage have been mediated by such specifically human disasters as inflation, unemployment, and political tyranny. An account of past crises, periods of relative relief from population pressure, and resulting cycles, is given for a number of regions: China, North Africa and Western Asia, the northern Mediterranean, and north-western Europe. The paper ends with an account of the present world-wide population crisis, and the solution

  16. Imaginary populations

    Directory of Open Access Journals (Sweden)

    A. Martínez–Abraín

    2010-01-01

    Full Text Available A few years ago, Camus & Lima (2002 wrote an essay to stimulate ecologists to think about how we define and use a fundamental concept in ecology: the population. They concluded, concurring with Berryman (2002, that a population is "a group of individuals of the same species that live together in an area of sufficient size to permit normal dispersal and/or migration behaviour and in which population changes are largely the results of birth and death processes". They pointed out that ecologists often forget "to acknowledge that many study units are neither natural nor even units in terms of constituting a population system", and hence claimed that we "require much more accuracy than in past decades in order to be more effective to characterize populations and predict their behaviour". They stated that this is especially necessary "in disciplines such as conservation biology or resource pest management, to avoid reaching wrong conclusions or making inappropriate decisions". As a population ecologist and conservation biologist I totally agree with these authors and, like them, I be¬lieve that greater precision and care is needed in the use and definition of ecological terms. The point I wish to stress here is that we ecologists tend to forget that when we use statistical tools to infer results from our sample to a population we work with what statisticians term "imaginary", "hypothetical" or "potential" popula¬tions. As Zar (1999 states, if our sample data consist of 40 measurements of growth rate in guinea pigs "the population about which conclusions might be drawn is the growth rates of all the guinea pigs that conceivably might have been administered the same food supplement under identical conditions". Such a population does not really exist, and hence it is considered a hypothetical or imaginary population. Compare that definition with the population concept that would be in our minds when performing such measurements. We would probably

  17. Population policy.

    Science.gov (United States)

    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

  18. Population dynamics

    Directory of Open Access Journals (Sweden)

    Cooch, E. G.

    2004-06-01

    Full Text Available Increases or decreases in the size of populations over space and time are, arguably, the motivation for much of pure and applied ecological research. The fundamental model for the dynamics of any population is straightforward: the net change over time in the abundance of some population is the simple difference between the number of additions (individuals entering the population minus the number of subtractions (individuals leaving the population. Of course, the precise nature of the pattern and process of these additions and subtractions is often complex, and population biology is often replete with fairly dense mathematical representations of both processes. While there is no doubt that analysis of such abstract descriptions of populations has been of considerable value in advancing our, there has often existed a palpable discomfort when the ‘beautiful math’ is faced with the often ‘ugly realities’ of empirical data. In some cases, this attempted merger is abandoned altogether, because of the paucity of ‘good empirical data’ with which the theoretician can modify and evaluate more conceptually–based models. In some cases, the lack of ‘data’ is more accurately represented as a lack of robust estimates of one or more parameters. It is in this arena that methods developed to analyze multiple encounter data from individually marked organisms has seen perhaps the greatest advances. These methods have rapidly evolved to facilitate not only estimation of one or more vital rates, critical to population modeling and analysis, but also to allow for direct estimation of both the dynamics of populations (e.g., Pradel, 1996, and factors influencing those dynamics (e.g., Nichols et al., 2000. The interconnections between the various vital rates, their estimation, and incorporation into models, was the general subject of our plenary presentation by Hal Caswell (Caswell & Fujiwara, 2004. Caswell notes that although interest has traditionally

  19. Populations games

    Czech Academy of Sciences Publication Activity Database

    Křivan, Vlastimil

    2015-01-01

    Roč. 2, č. 1 (2015), s. 14-19 ISSN 2367-5233. [Featuring International Conferences Biomath 2015. Blagoevgrad, 14.06.2015-19.06.2015] R&D Projects: GA MŠk(CZ) EE2.3.30.0032 Institutional support: RVO:60077344 Keywords : populations dynamics

  20. Stellar Populations

    NARCIS (Netherlands)

    Peletier, Reynier F.

    2013-01-01

    This is a summary of my lectures during the 2011 Canary Islands Winter School in Puerto de la Cruz. I give an introduction to the field of stellar populations in galaxies, and highlight some new results. Since the title of the Winter School is Secular Evolution in Galaxies I mostly concentrate on

  1. MAIZE POPULATIONS

    African Journals Online (AJOL)

    2003-06-17

    Jun 17, 2003 ... This study compared two maize populations, ZM601 and. ZM607 for drought tolerance during flowering, the most drought-vulnerable period for the maize plant. Cultivar. ZM601 had been improved through ...... Banziger, M., Pixley, K.V. and Zambezi, B.T.. 1999. Drought andNstress tolerance of maize.

  2. Population Aging

    OpenAIRE

    David Weil

    2006-01-01

    Population aging is primarily the result of past declines in fertility, which produced a decades long period in which the ratio of dependents to working age adults was reduced. Rising old-age dependency in many countries represents the inevitable passing of this %u201Cdemographic dividend.%u201D Societies use three methods to transfer resources to people in dependent age groups: government, family, and personal saving. In developed countries, families are predominant in supporting children, w...

  3. Stickleback Population

    Directory of Open Access Journals (Sweden)

    Ulrika Candolin

    2012-01-01

    Full Text Available Human-induced eutrophication has increased offspring production in a population of threespine stickleback Gasterosteus aculeatus in the Baltic Sea. Here, we experimentally investigated the effects of an increased density of juveniles on behaviours that influence survival and dispersal, and, hence, population growth—habitat choice, risk taking, and foraging rate. Juveniles were allowed to choose between two habitats that differed in structural complexity, in the absence and presence of predators and conspecific juveniles. In the absence of predators or conspecifics, juveniles preferred the more complex habitat. The preference was further enhanced in the presence of a natural predator, a perch Perca fluviatilis (behind a transparent Plexiglas wall. However, an increased density of conspecifics relaxed the predator-enhanced preference for the complex habitat and increased the use of the open, more predator-exposed habitat. Foraging rate was reduced under increased perceived predation risk. These results suggest that density-dependent behaviours can cause individuals to choose suboptimal habitats where predation risk is high and foraging rate low. This could contribute to the regulation of population growth in eutrophicated areas where offspring production is high.

  4. Bacteriophage populations

    International Nuclear Information System (INIS)

    Klieve, A.V.; Gilbert, R.A.

    2005-01-01

    Bacteriophages are ubiquitous to the rumen ecosystem; they have a role in nitrogen metabolism through bacterial lysis in the rumen, they may help to regulate bacterial population densities, be an agent for genetic exchange and be of use in biocontrol of bacterial populations through phage therapy. In Chapter 2.1, classical methodologies to enable the isolation, enumeration, storage and morphological characterization of phages were presented. In addition to these classic procedures, molecular biological techniques have resulted in a range of methodologies to investigate the type, topology and size of phage nucleic acids, to fingerprint individual phage strains and to create a profile of ruminal phage populations. Different phage families possess all the currently identified combinations of double-stranded or single-stranded RNA or DNA and may also possess unusual bases such as 5-hydroxymethylcytosine (found in T-even phage) or 5- hydroxymethyluracil and uracil in place of thymidine. In all morphological groups of phage except the filamentous phages, the nucleic acid is contained within a head or polyhedral structure, predominantly composed of protein. Filamentous phages have their nucleic acid contained inside the helical filament, occupying much of its length. Many of the procedures used with phage nucleic acids and double-stranded (ds) DNA, in particular, are not specific to ruminal phages but are the same as in other areas where nucleic acids are investigated and are covered elsewhere in the literature and this chapter. Most applications with rumen phages are similar to those reported for phages of non-ruminal bacteria and are covered in general texts such as Maniatis et al. In this chapter, we will concentrate on aspects of methodology as they relate to ruminal phages

  5. Indian populations

    CERN Document Server

    Spahni,J

    1974-01-01

    Le Prof. J.C. Spahni qui a parcouru les Andes, Vénezuela etc. parle de ses expériences et connaissances qu'il a vécu au cours des 14 ans parmi les populations indiennes de la Cordillière des Andes. Il a ramené des objets artisanals indiens lesquels l'auditoire peut acquérir. L'introduction-conférence est suivi d'un film, commenté par lui-même; après l'entracte il y un débat-dialogue avec le public.

  6. Population growth rates in perfect contraceptive populations.

    Science.gov (United States)

    Udry, J R; Bauman, K E; Chase, C L

    1973-07-01

    Abstract Eventually, world population must cease to grow. In many countries attempts are made to decrease population growth by providing family planning services to all who want to prevent pregnancies. In this paper we use the concept 'perfect contraceptive population',(1) - a population in which no unwanted births occur - to derive estimates of the maximum contribution that prevention of unwanted births might make toward attaining a zero rate of natural increase in population.

  7. Population Genetics with Fluctuating Population Sizes

    OpenAIRE

    Chotibut, Thiparat; Nelson, David R.

    2016-01-01

    Standard neutral population genetics theory with a strictly fixed population size has important limitations. An alternative model that allows independently fluctuating population sizes and reproduces the standard neutral evolution is reviewed. We then study a situation such that the competing species are neutral at the equilibrium population size but population size fluctuations nevertheless favor fixation of one species over the other. In this case, a separation of timescales emerges natural...

  8. Human Population Problems

    Science.gov (United States)

    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…

  9. Population Education Country Programmes.

    Science.gov (United States)

    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,…

  10. Why Population in 1974?

    Science.gov (United States)

    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)

  11. Population and population policy in Pakistan.

    Science.gov (United States)

    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.

  12. Population and Environment

    OpenAIRE

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

    2007-01-01

    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...

  13. Iowa Population Trends.

    Science.gov (United States)

    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…

  14. [Population Growth and Development].

    Science.gov (United States)

    Clausen, A. W.

    Rapid population growth as a central development problem, the proper domain of government in reducing population growth, and effective measures which can be taken to reduce fertility are examined. Rapid population growth puts a brake on development because it exacerbates the difficult choice between higher consumption now and the investment needed…

  15. Controlling Population with Pollution

    Science.gov (United States)

    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.

  16. Wnt signaling inhibition deprives small intestinal stem cells of clonogenic capacity

    Czech Academy of Sciences Publication Activity Database

    Janečková, Lucie; Fafílek, Bohumil; Krausová, Michaela; Horázná, Monika; Vojtěchová, Martina; Alberich-Jorda, Meritxell; Šloncová, Eva; Galušková, Kateřina; Sedláček, Radislav; Anděrová, Miroslava; Kořínek, Vladimír

    2016-01-01

    Roč. 54, č. 3 (2016), s. 101-114 ISSN 1526-954X R&D Projects: GA ČR(CZ) GA14-33952S; GA ČR(CZ) GAP303/12/0855; GA MŠk(CZ) ED1.1.00/02.0109; GA MŠk LO1220; GA MŠk LK21307; GA MŠk(CZ) LM2011032; GA MŠk EE2.3.30.0027 Institutional support: RVO:68378050 ; RVO:68378041 Keywords : b-catenin * Cre /loxP * gene targeting * gut * Wnt pathway * TCF/LEF transcription factors Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.143, year: 2016

  17. Dosimetry of irradiation models. The 96-well clonogenic assay for testing radiosensitivity of cell lines

    International Nuclear Information System (INIS)

    Kulmala, J.; Rantanen, V.; Turku Univ.; Pekkola-Heino, K.; Turku Univ.; Tuominen, J.; Grenman, R.; Turku Univ.

    1995-01-01

    Radiation experiments with cells in single cell suspension in test tubes and on 96-well plates were carried out and compared. The cells originated from cell lines established from carcinomas of the floor of the mouth and from endometrical carcinoma. Two irradiation models were constructed. Both models allowed the absorbed doses to the cells to be administered with a high accuracy in both experimental settings (better than 5.0%). These irradiation models were compared on cancer cell lines with dissimilar inherent radiation sensitivity and histologic type (UM-SCC-1 resistant, UM-SCC-14A sensitive, and UT-EC-2B highly sensitive); various radiation doses were used. The fractions of surviving cells as a function of radiation dose were compared: there was no significant difference between cells irradiated in test tubes and cells irradiated in 96-well plates. Thus, if the absorbed doses in cells suspended in a tube and in a plate were the same, the survival was similar regardless of the type of irradiation model. (orig.)

  18. [Population policies and population trends in China].

    Science.gov (United States)

    Pressat, R

    1983-04-01

    Although relatively little has been known about the Chinese population in recent centuries, figures are available for more remote times. In the year 2 the Chinese population was recorded at 60 million. In 1928, when the last pre-Revolution census was conducted, China had a population of 475 million. The population was not believed to have grown very much due to internal disorders, war, and foreigh invasion, but the 1953 census counted 582 million to which were added 18 million to include Taiwan and overseas Chinese. The figure of 600 million appears to mark the beginning of concern over demographic problems. The crude birth rate was estimated at 37/1000 and the death rate at 17/1000. The 1953 census was conducted with Soviet aid and was given some publicity. The period 1953-58 was marked by a mortality decline and a steady fertility rate, but the population is believed to have declined from 647 million in 1958 to 643 million in 1962, the end of the Great Leap Forward. A census suppressed until recently gave a total of 694 million for 1964. Population growth was considerable from 1961-66. In the 1st part of the Cultural Revolution from 1966-70, no effort was made to control population growth; in 1971, the crude birth rate was estimated at 30-35/1000, the mortality rate was 8/1000, and the growth rate was 2.6%. 1971-79 marked the 1st phase of birth limitation, which became more pressing with time. The population was counted at 1 billion 8 million in 1982, with a birth rate of 21/1000, a death rate of 6/1000, and a growth rate of 1.5%. Because of China's comprehensive system of population registration, the results of the 1982 census were not completely unexpected. Wide differences in growth rates were noted between provinces, and the minorities grew at a faster rate than the Han majority. Immediately after the Revolution, population was relatively neglected in China in favor of greater attention to economic growth. The 1st warnings about the consequences of overly

  19. Peru: population and policy.

    Science.gov (United States)

    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.

  20. Molecular Population Genetics.

    Science.gov (United States)

    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.

  1. Molecular Population Genetics

    Science.gov (United States)

    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

  2. Population and Environment

    OpenAIRE

    Theodore Panayotou

    2000-01-01

    The past fifty years have witnessed two simultaneous and accelerating trends: an explosive growth in population and a steep increase in resource depletion and environmental degradation. These trends have fueled the debate on the link between population and environment that began 150 years earlier, when Malthus voiced his concern about the ability of the earth and its finite resources to feed an exponentially growing population. The purpose of this study is to review the literature on populati...

  3. Measurably evolving populations

    DEFF Research Database (Denmark)

    Drummond, Alexei James; Pybus, Oliver George; Rambaut, Andrew

    2003-01-01

    processes through time. Populations for which such studies are possible � measurably evolving populations (MEPs) � are characterized by sufficiently long or numerous sampled sequences and a fast mutation rate relative to the available range of sequence sampling times. The impact of sequences sampled through...... time has been most apparent in the disciplines of RNA viral evolution and ancient DNA, where they enable us to estimate divergence times without paleontological calibrations, and to analyze temporal changes in population size, population structure and substitution rates. Thus, MEPs could increase our...

  4. Effect of estradiol on proliferation and differentiation of side population stem/progenitor cells from murine endometrium

    Directory of Open Access Journals (Sweden)

    Xu Jing

    2011-07-01

    Full Text Available Abstract Background In our previous study, endometrium side population cells (SP cells were isolated from postpartum murine uterus, and characterized by a heterogeneous population of stem/progenitor cells. In this study, we investigated the effect of estrogen on the proliferation and differentiation of SP cells. Methods SP and non-SP cells of postpartum murine endometrium were isolated by DNA dye Hoechst 33342. The expression of estrogen receptor 1 (ESR1 was measured by reverse transcription polymerase chain reaction (RT-PCR, Real-time PCR, Western blot, immunofluorescence and immunohistochemistry. The proliferation and differentiation of SP cells treated with different concentrations [10(-8 M-10(-6 M] of estradiol (E2 and E2+ ICI182780 (Faslodex, inhibitor of ESR1 were measured by 3-(4, 5-dimethylthiazoly1-2-2,5-diphenyltetrazolium bromide(MTT and clonogenic assays. Results (1 SP cells expressed ESR1 at a higher level than non-SP cells. (2 The level of E2 in the serum and the expression of ESR1 in the uterus of postpartum murine changed in the same manner with the ratio of SP cells to total uterus cells at a different postpartum time point. ESR1, as ABCG2 is also predominantly located in the stroma and the glandular epithelium of the uterus. (3 10(-6 M E2 notably promoted the proliferation of SP cells after treatment for 24 h. This effect could be inhibited by ICI182780. E2 at the concentration of 10(-7 M or 10(-8 M was sent to impair the large cloning efficiency (CE of SP cells. Conclusions The effect of estrogen on the proliferation and differentiation of endometrium SP cells via ESR1 was observed and it was in a concentration dependent fashion. Clearly, more work is needed to understand the in vivo effect of E2 at the physiological concentration on the differentiation of SP cells.

  5. The PSA−/lo prostate cancer cell population harbors self-renewing long-term tumor-propagating cells that resist castration

    Science.gov (United States)

    Qin, Jichao; Liu, Xin; Laffin, Brian; Chen, Xin; Choy, Grace; Jeter, Collene; Calhoun-Davis, Tammy; Li, Hangwen; Palapattu, Ganesh S.; Pang, Shen; Lin, Kevin; Huang, Jiaoti; Ivanov, Ivan; Li, Wei; Suraneni, Mahipal V.; Tang, Dean G.

    2012-01-01

    SUMMARY Prostate cancer (PCa) is heterogeneous and contains both differentiated and undifferentiated tumor cells, but the relative functional contribution of these two cell populations remains unclear. Here we report distinct molecular, cellular, and tumor-propagating properties of PCa cells that express high (PSA+) and low (PSA−/lo) levels of the differentiation marker PSA. PSA−/lo PCa cells are quiescent and refractory to stresses including androgen deprivation, exhibit high clonogenic potential, and possess long-term tumor-propagating capacity. They preferentially express stem cell genes and can undergo asymmetric cell division generating PSA+ cells. Importantly, PSA−/lo PCa cells can initiate robust tumor development and resist androgen ablation in castrated hosts, and harbor highly tumorigenic castration-resistant PCa cells that can be prospectively enriched using ALDH+CD44+α2β1+ phenotype. In contrast, PSA+ PCa cells possess more limited tumor-propagating capacity, undergo symmetric division and are sensitive to castration. Together, our study suggests PSA−/lo cells may represent a critical source of castration-resistant PCa cells. PMID:22560078

  6. Population and development.

    Science.gov (United States)

    1999-04-01

    This article highlights improvements in China's population development, particularly in its family planning programs. China first realized the importance of family planning in 1962. 2 years later, a Family Planning Office was established under the State Council, which was upgraded into a Leading Group in 1973, and population began to be incorporated into national planning. In 1981, the State Family Planning Commission was established as a ministry-level organization directly under the State Council. In 1982, the government further defined its population policy as "controlling population growth and improving population quality.¿ Moreover, in the wake of the International Conference on Population Development in 1994 and the Fourth World Conference on Women in 1995, China has called for reorientations in family planning programs and in social regulations. This article also presents the efforts of the Chinese government to protect the country's environment and the employment of certain measures to facilitate population migration in response to the needs of the migrant population for family planning and health care.

  7. The Population Activist's Handbook.

    Science.gov (United States)

    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. The World Population Dilemma.

    Science.gov (United States)

    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…

  9. Glaucoma in Asian Populations

    Science.gov (United States)

    ... is expected to become an even more serious problem as the world population and longevity increases. The other major glaucoma type ... of all cases of blindness from glaucoma in China. There is great racial diversity among Asian populations, and these differences are represented in the presentation ...

  10. Population. Headline Series.

    Science.gov (United States)

    Oppenheimer, Valerie K.

    Useful as background reading or secondary classroom material, this pamphlet reviews several dimensions of world population growth and control. The first of seven chapters, World Population Growth: Past, Present and Future, discusses some of the reasons for the greatly accelerated growth since 1950, and points out that even significantly rapid…

  11. Regional Population Dynamics

    Science.gov (United States)

    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...

  12. Negative Drift in Populations

    DEFF Research Database (Denmark)

    Lehre, Per Kristian

    2011-01-01

    An important step in gaining a better understanding of the stochastic dynamics of evolving populations, is the development of appropriate analytical tools. We present a new drift theorem for populations that allows properties of their long-term behaviour, e.g. the runtime of evolutionary algorithms...

  13. Stockholm sidesteps population issue.

    Science.gov (United States)

    1972-08-01

    Population policies were discussed during a U.N. Conference on the Human Environment held in Stockholm in June 1972. Although it was acknowledged that people in developed countries have a much more detrimental impact on the environment due to their high levels of consumption, various positions were taken on the importance of family planning in developing countries. Both the Chinese delegate and Indira Ghandi of India remarked that one cannot blame overpopulation for ecological problems. Other speakers agreed that technology would solve ecological problems and that population growth rates would take care of themselves when development occurred. Other speakers, such as Dr. Paul Ehrlich believe that worldwide stabilization of population is necessary to maintain life-support systems of this planet. The majority of delegates to the Conference did not consider the reduction of population growth to be a priority, although it was recommended that national governments develop population policies, and that WHO give increased support to family planning activities. It was also recommended that adequate attention be given to the relationship between population and environment at the World Population Conference in 1974.

  14. The population threat.

    Science.gov (United States)

    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

  15. Predation and caribou populations

    Directory of Open Access Journals (Sweden)

    Dale R. Seip

    1991-10-01

    Full Text Available Predation, especially wolf (Canis lupus predation, limits many North American caribou (Rangifer tarandus populations below the density that food resources could sustain. The impact of predation depends on the parameters for the functional and numerical response of the wolves, relative to the potential annual increment of the caribou population. Differences in predator-avoidance strategies largely explain the major differences in caribou densities that occur naturally in North America. Caribou migrations that spatially separate caribou from wolves allow relatively high densities of caribou to survive. Non-migratory caribou that live in areas where wolf populations are sustained by alternate prey can be eliminated by wolf predation.

  16. Immunization in special populations.

    Science.gov (United States)

    Miller, Michael A; Rathore, Mobeen H

    2012-01-01

    In summary, immunizations in special populations require understanding the underlying disease and how it might affect the immune system's ability to mount an antibody response to vaccines or predispose certain patient populations to developing certain serious infections. There is still a great need for research on the optimal timing of vaccines after transplants, how to assess protection and development of a protective antibody response after immunization, and whether certain groups (eg, HIV) need to be revaccinated after a certain amount of time if their antibody levels decline. In addition, there are limited data on efficacy of the newer vaccines in these special patient populations, which also requires further investigation.

  17. Populated Places of Iowa

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — This coverage contains points that represent populated places, ie. cities, towns, villages or any other named place where people live. The coverage was developed...

  18. Parallel grid population

    Science.gov (United States)

    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.

  19. Fish population dynamics

    National Research Council Canada - National Science Library

    Gulland, J. A

    1977-01-01

    This book describes how the dynamics of fish populations can be analysed in terms of the factors affecting their rates of growth, mortality and reproduction, with particular emphasis on the effects of fishing...

  20. County Population Vulnerability

    Data.gov (United States)

    City and County of Durham, North Carolina — This layer summarizes the social vulnerability index for populations within each county in the United States at scales 1:3m and below. It answers the question...

  1. Market Squid Population Dynamics

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains population dynamics data on paralarvae, juvenile and adult market squid collected off California and the US Pacific Northwest. These data were...

  2. Food for tomorrow's population.

    Science.gov (United States)

    Hugo, G

    1983-06-01

    This discussion outlines and clarifies the dimensions of the world's current food-population balance and examines likely future changes in this balance over the next 20 years. The 1st section summarizes the contemporary world demographic situation in the early 1980s, focusing on regional differences in patterns of population growth and the significant food shortages in the developing countries. A subsequent section considers the outlook for population growth up to the year 2000 with particular reference to the most recent UN population projects. The discussion of food production and supply includes some specific comments on the situation in Indonesia. The world's population in 1983 has been estimated at 4677 million. It will reach 5 billion in the next 5 years. The countries which can least afford it are growing the fastest. These countries will account for 79% of the world's population in 2000 and 83% by 2020. Fertility in the less developed countries (LDCs) is twice that of more developed countries, with women in the former group having an average of around 4.5 children and in the latter, 1.9. The substantial declines in fertility in many countries are not fully reflected in declines in population growth and natural increase rates. This is because of major improvements which have occurred in mortality. During recent decades there has been a marked increase in world food production. In the developed countries increases in food production have continued at more than twice those for population, but this was not the case in the less developed countries where the margin narrowed during the 1950s and 1960s until in the early 1970s population was increasing at a slightly faster rate overall than was food production. Food crisis situations continue to occur with disturbing frequency in several regions. Seasonal, regional, and national variations in food shortages are not the only dimensions to food-population imbalances. Within nations there is inequality in access to

  3. EDUCATION AND ROMA POPULATION

    Directory of Open Access Journals (Sweden)

    Ana Asensio Belenguer

    2016-07-01

    Full Text Available This article deals with Education and the Roma Population. It presents an approach to schooling of Romani children since its outset in the city of Zaragoza (Spain. It analyzes the current status as presented by the Strategy for Social Inclusion of this people 2012-2020, and collects, from various sources, the fact that education remains a pending challenge for Roma Population. Measures to be taken by the educational community from a gender and inclusive perspective are proposed.

  4. Population Density Modeling Tool

    Science.gov (United States)

    2012-06-26

    194 POPULATION DENSITY MODELING TOOL by Davy Andrew Michael Knott David Burke 26 June 2012 Distribution...MARYLAND NAWCADPAX/TR-2012/194 26 June 2012 POPULATION DENSITY MODELING TOOL by Davy Andrew Michael Knott David Burke...information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE 26

  5. The politics of population.

    Science.gov (United States)

    Wolfson, M

    1986-03-01

    This article suggests some of the principal factors behind the decisions by an increasing number of countries deciding that the achievement of their national objectives required a policy for population, and the way that they are likely to work out. By 1983, 35 developing countries had an official policy to reduce their population growth rate, and in 34 others, the government supported family planning activities--usually for reasons of health or as a human right. The number is remarkable given the many compelling reasons that governments have for not attempting anything so difficult as to modify demographic trends. The future results of population programs, in social and economic terms, are very difficult to quantify, thus defying cost-benefit analysis of the desirability of investing resources in this area, rather than in something else. There are also powerful political reasons why a government might well hesitate before embarking on a policy to reduce the nation's fertility. At the very least, it implies government interference in the most private and personal of human relations, an invasion of human rights, and a disturbance of the traditional patterns of society and behavior. For many countries that are pursuing a policy to limit population growth, the decision has been taken only after the grievous consequences of not having such a policy have already become manifest. The critical question is how soon a government will make the connection among political disobedience, economic and social distress, and the population explosion, and adopt a population policy. Although the number of developing countries that have officially proclaimed a strongly pro-natalist population policy is relatively small, many have Marxist governments. Overall, governments have several strategies at their disposal: 1) improving the accessability and the quality of the service; 2) promoting population education and family planning motivation (with the assistance of the media, folk art, and

  6. Rapid population growth.

    Science.gov (United States)

    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.

  7. Population: sources and trends.

    Science.gov (United States)

    Keane, J G

    1986-01-01

    Most of the data on US immigration flows do not come from the Census Bureau; rather, data from the Immigration and Naturalization Service, on the number of legal migrants entering the country, and from the Office of Refugee Resettlement on the number of refugees entering the country is used. Between 1970 and 1980, the foreign-born population in the US grew by some 4.5 million persons or an astounding 46%. The foreign-born population in the US is concentrated in a few geographic areas; 3.6 million, or 1/4 of the foreign-born, live in California, and New York and Florida together have another 1/4 of the foreign-born population. The concentration of the foreign-born population is very pronounced in metropolitan areas. Mexico supplied the largest fraction of the foreign-born population in the 1980 census. Over 5 out of every 6 or 84% of the foreign-born persons who came to the US before 1950 were born in Europe or Canada. The shift from Europe as the main source of immigration was marked by a shift to Latin America and Asia as the principal sources of recent migrants to the US. The Census Bureau has made a number of projections using different scenarios for fertility, mortality, and immigration. The middle migration series, roughly consistent with current levels of legal immigration, shows that the population would grow to about 311 million by 2080 from a current level of 237 million.

  8. Vietnam's population: current notes.

    Science.gov (United States)

    Fraser, S E

    1984-06-01

    In an effort to curb the population growth rate, currently estimated at 2.5%/year, the government of Vietnam has stepped up its campaign to implement a national family planning program. 1979 census figures indicate a population of 52.76 million. There is increasing government awareness of the interaction between population growth, employment, and manpower utilization. The demographic realities of Vietnam necessitate a drastic decrease in fertility rates and family size, a redistribution of the population either through internal migration to new economic zones or transborder migration, and a more efficient use of land and exploitation of natural and human resources to support the growing population. Assuming a natural increase rate of less than 2% by 1984-85, the government estimates a total population of nearly 60 million by the end of 1985. It is hoped that a natural growth rate of 1% can be attained in the early 1990s, to achieve a population size below 75 million by the year 2000. However, if the 3-child family remains the norm, the population will approach 80-85 million by 2000. Changes in shortterm fertility patterns seem unlikely without a carefully thought out and sensitively implemented policy involving a deliberate scheme of incentives and disincentives. The Vietnam Fatherland Front (VFF) has recognized the need for a more regorous fertility control campaign and has requested that the Council of Ministers set up a coordinated population and family planning structure with direct linkages from Hanoi to provincial governments and communal administrations. Also recommended were regulations on birth control, population targets and norms, and a system of incentives and disincentives. Data from family planning services in Ho Chi Minh City for 1976-82 suggest a recent decline in IUD, condom, and pill users, largely as a result of procurement difficulties. The number of abortions has also declined because of successful family planning education. The ideal family

  9. Population and the environment.

    Science.gov (United States)

    1987-01-01

    The pressures created by increasing number of people and increasing migration have aggravated environmental and resource problems in many developing countries. To deal with these problems, there is a need to formulate mutually supportive population and environmental policies. Especially in developing countries, where most of the world's population growth will occur and where there will be the greatest growth in urban centers. Efforts to promote development in a way that preserves the resource base for future generations will have to take into account demographic factors, since excessive population pressure in specific geographical areas can pose serious ecological hazards, including soil erosion, desertification, dwindling firewood supplies, deforestation, and the degradation of fresh water sources. Often the link between population pressure and those types of environmental stress is the growth in the relative and absolute number of persons living in poverty. The result is marginalization of small-scale farmers and pressure on larger numbers to migrate from distressed areas, and increased prevalence of environmentally related diseases. Population policies should also be formulated with due regard for environmental factors, with priority in those geographical areas likely to experience acute environmental stress. Programs for influencing the distribution of population should also consider the environmental impact. Monitoring and forecasting of likely changes in the status of key natural resources should be communicated to communities to obtain grass-roots support. Ultimately, however, problems of population and the environment can only be resolved in the context of a comprehensive program at the national and international levels to promote economic and social development.

  10. Population and environment.

    Science.gov (United States)

    1997-04-01

    This article discusses the recent February 1997 Mainichi Newspaper symposium entitled "Securing the Safety of the Biosphere: The Population Explosion and the Global Environment," held in Tokyo, Japan. The symposium was a tribute to the commitment of the newspaper company to global population and environmental issues. Dr. Fred Sai, past president of IPPF, was a guest speaker. Both Dr. Sai and the Mainichi were honored in 1993 with the UN Population Award. A symposium outcome was the "Tokyo Declaration." The declaration was developed by the 21st Century Environmental Crisis Warning Committee under the direction of the Mainichi Newspapers and by international experts. The declaration called for appropriate population policies, respect for women's full participation in society, gender equality, the rights of women to determine their own sexual and reproductive health, and the rights of children to a healthy mind and body. Other speakers included the executive coordinator of United National Reform, the chairman of the Earth Council, the chairman of the Intergovernmental Panel on Climatic Change, the president of the World Watch Institute, and the chairman of the Swaminathan Research Foundation. The director of the Study and Research Division of JOICFP spoke about including women's views into discussions about population and the environment. Women were credited with playing an important population control role at the grassroots level. It was argued that population is reduced best by meeting the unmet needs of women and providing reproductive health services. Women and couples should be guaranteed informed choice. The issue of abortion availability should not be based on religious or social values.

  11. The population of Brazil

    Directory of Open Access Journals (Sweden)

    João Yunes

    1972-12-01

    Full Text Available In 1970 the population of Brazil with 94,508,554 inhabitants was extreme youth, since 42.67% was composed of children under 14 years old. In that year the proportion of female was 50.2%. The population density increased from 1.17 inhabitants /km² in 1872 to 11.18 in 1970, and in this last year the range was 1.03 in the North region and 43.90 in the South-East region. The urban population increased from 31.24% in 1940 to 55.98% in 1970 and for the first time the rural population was smaller than the urban population. In 1950 concerning with marital status 39% of the population 15 years old and over was single and 54% married. In 1970 this rate was respectively 35.4% and 56.6%. The population economically inactive increased from 49.17% in 1940 to 52.24% in 1970. The literacy ratio increased from 43% in 1940, to 48% in 1950 and 68.04% in 1970. The crude birth rate was 43/1000 live births in 1950 and fell to 37.7/1000 in 1970. The fertility rate decreased from 179.3/1000 women (15-49 years old} to 156.7/1000 in 1960/70. The crude death rate decreased from 20.60/1000 inhabitants in 1940/50 to 9.4/1000 in 1960/70. The infant mortality rate still remains high: 171/1000 live births in 1940/50 and 170/1000 in 1971. Concerning with the size of the cities, 8 in 1940 had 100,000 or more inhabitants and in 1970 this number increased to 94 cities. The population growth increased from 2.38% in 1940/50, to 2.99% in 1950/60 and 2.83% in 1960./70. Brazil is the first country in population size in Latin America and the eighth in the world. Concerning his area, Brazil is the fifth country in size.

  12. Alternative population futures.

    Science.gov (United States)

    1980-01-01

    The Philippines is now passing through a late demographic transitional period in which the death rate declines while the birth rate remains at a relatively high level; the population of young people under 15 rises to about 45% of the population while proportions of people of working age and old people decline. In 1970, 4 of the Philippine's 12 regions had a birth rate exceeding 40/1000; life expectancy at birth in these regions ranged from 57-64 years and population growth rates ranged from 2.6-4.2% annually. Also in 1970 40-49% of all 12 regional populations were young (under 15) and only 2-5% were old. In this transitional period there are a greater number of children in each household and thus heavier social and economic burdens occur; also the burden of youth dependency increases by more than 1/3. In the modern population structure, family burdens diminish as the average number of children surviving to age 20 becomes identical with the number of children born and great improvements in the quality of life are allowed. Population projections are based on the following assumptions: 1) decrease in mortality, either rapid or slow, 2) increase in age at marriage, 3) decline in fertility will remain at 0.7% annually, and 4) migration trends will stay the same as during the 1960-75 period. Total population is expected to reach 83.8 million by 2000, a 98% increase from 1975; a low estimate, assuming lower fertility and nuptiality, is 64.1 million, a 52% increase from 1975. The urban population will more than double its size by the year 2000 and rural population will grow from 22-65% with the fastest urbanizing regions being the Central and Southern Luzon. From 1975-2000 a 3-fold increase is expected in the number of families in Metro Manila. By 2000 a national labor force of 27.5 million is expected, more than double the 1970 level, with late entry into the labor force and declines in participation by elderly males. The various regions will see lower economic activity

  13. Population explosion, social change.

    Science.gov (United States)

    Pethe, V P

    1983-01-26

    The issue of whether overpopulation is the cause of poverty or vice versa is a sham controversy. Both population explosion and poverty are symptoms of a deeper problem, i.e., the incapacity of the socioeconomic system and the international economic order to put into service modern science and technology for an optimal utilization of this planet's vast resources for economic development. There is no question that population growth cannot be allowed to go unabated for an indefinite period, yet there is no reason for alarm. History shows that human adjustments in social behavior have always restored equilibria in every crisis in the progress of humankind. Neo-Malthusians fail to see this point. Instead, they try to create a scare by making unrealistic projections. There is no need for the incorrect and dangerous neo-Malthusian theory as a way to plead for checking population growth. There are 3 simple reasons why population growth should slow down: populations in most less developed countries have a size sufficiently large to make them militarily and economically viable and will not face serious problems in economic and social management if their populations get stabilized at the current levels; there are several advantages in changing attitudes and behavior patterns in respect to matters such as marriage age, family limitation, and spacing of children, and these are desirable in their own right besides their effect on reducing fertility and population growth; and a need exists to intervene on the side of fertility in order to maintain the longrun equilibrium of population size. In the past, equilibrium between mortality and fertility was achieved through the operation of natural factors. Now, with the reduction in mortality as a result of human intervention, it has become necessary to bring about a decline in fertility through human intervention. Human intervention in the control of fertility is a difficult and complex process. The solution to the population

  14. Mexico's population: a profile.

    Science.gov (United States)

    Paul, N

    1987-05-01

    Mexico's population is estimated at 82 million in 1987, making it the 2nd most populous country of Latin America after Brazil. This demographic explosion is a classic example of what occurs when modern technology is suddenly infused into a traditional society: death rates decline rapidly due to improved health care and better living standards, while the birth rate remains high. In 1973, the pronatalist law on population dating from 1947 was drastically revised, signalling the start of a series of direct and indirect measures to reduce population growth. Today, slow economic growth and capital scarcity make it difficult to create new industries that might provide some employment. Mexican workers have been migrating to the US since the 1800s, but more are entering the US now than ever before. Rural-to-urban migration in Mexico is creating a drop in food production and putting severe strains on city housing, school systems, transportation, and medical facilities. The new immigration law introduced by the US Congress adds a new dimension to Mexico's future; Mexicans fear that the return of 1000s of workers will have severe repercussions on their economy, as the numbers of unemployed will increase. Overall, strong structural changes, close to the root of the problem, are needed. In this case, a revival of the Mexican economy, using a determined population policy is 1 strategy.

  15. Population and development.

    Science.gov (United States)

    Ramana, D V

    1977-10-01

    Between 1950-1976 world population increased by 1.5 billion and was accompanied by unprecedented levels of poverty, unemployment, and inequality. Additional problems associated with this marked population increase are related to food supply, human resource development, the infrastructure component of human organization - housing, water supply, and lighting - and environment. Consequently, it becomes apparent that for purposes of development over the next generation or so, it is the absolute population size and its built-in momentum for increase that becomes relevant rather than the declaration of the population growth rate. Necessary is a model of development in which both consumption and investment expenditures are planned in such a way as to yield the highest possible social rate of return. Investment and consumption planning is required as instrumentalities for making income accrue directly to as great a section of the poor as possible. Simultaneously, the following action should be initiated for decreasing the fertility rate to replacement levels: provision of family planning services, education of all social groups regarding the effects of large families and rapid population growth, provision of alternative careers to motherhood, equal rights for women, and reshaping economic and social policies to encourage small families.

  16. Intrinsically dynamic population models

    Directory of Open Access Journals (Sweden)

    Robert Schoen

    2005-03-01

    Full Text Available Intrinsically dynamic models (IDMs depict populations whose cumulative growth rate over a number of intervals equals the product of the long term growth rates (that is the dominant roots or dominant eigenvalues associated with each of those intervals. Here the focus is on the birth trajectory produced by a sequence of population projection (Leslie matrices. The elements of a Leslie matrix are represented as straightforward functions of the roots of the matrix, and new relationships are presented linking the roots of a matrix to its Net Reproduction Rate and stable mean age of childbearing. Incorporating mortality changes in the rates of reproduction yields an IDM when the subordinate roots are held constant over time. In IDMs, the birth trajectory generated by any specified sequence of Leslie matrices can be found analytically. In the Leslie model with 15 year age groups, the constant subordinate root assumption leads to reasonable changes in the age pattern of fertility, and equations (27 and (30 provide the population size and structure that result from changing levels of net reproduction. IDMs generalize the fixed rate stable population model. They can characterize any observed population, and can provide new insights into dynamic demographic behavior, including the momentum associated with gradual or irregular paths to zero growth.

  17. World population in transition.

    Science.gov (United States)

    Merrick, T W

    1986-04-01

    The world's population growth rate peaked at slightly over 2%/year in the late 1960s and in 1986 is down to 1.7% and falling. Annual numbers added continue to rise because these rates apply to a very large base, 4.9 billion in 1986. According to UN medium variant projections, world population growth will peak at 89 million/year in the late 1990s and then taper off until world population stabilizes in the late decade of the 21st century at about 10.2 billion. Close to 95% of this growth is occurring in less developed countries (LDCs) of Africa, Asia (minus Japan), and Latin America. LDC fertility rates are declining, except in sub-Saharan Africa and parts of Latin America and South Asia, but most have far to go to reach the replacement level of 2.1 births/woman. Fertility is below replacement in virtually all more developed countries. For LDCs, large numbers will be added before stabilization even after attainment of replacement level fertility because of the demographic momentum built into their large and young population bases. This complicates efforts to bridge gaps between living standards in LDCs and industrialized countries. From a new debate about whether rapid population growth deters or stimulates economic growth, a more integrated view has emerged. This view recognizes the complementary relationship between efforts to slow population growth and other development efforts; e.g., to improve health and education, upgrade women's status, increase productivity. Most effective in the increased contraceptive prevalence and fertility declines seen in many LDCs has been the combination of organized programs to increase access to family planning information and supplies with socioeconomic development that enhances the desire for smaller families.

  18. [Population problem, comprehension problem].

    Science.gov (United States)

    Tallon, F

    1993-08-01

    Overpopulation of developing countries in general, and Rwanda in particular, is not just their problem but a problem for developed countries as well. Rapid population growth is a key factor in the increase of poverty in sub-Saharan Africa. Population growth outstrips food production. Africa receives more and more foreign food, economic, and family planning aid each year. The Government of Rwanda encourages reduced population growth. Some people criticize it, but this criticism results in mortality and suffering. One must combat this ignorance, but attitudes change slowly. Some of these same people find the government's acceptance of family planning an invasion of their privacy. Others complain that rich countries do not have campaigns to reduce births, so why should Rwanda do so? The rate of schooling does not increase in Africa, even though the number of children in school increases, because of rapid population growth. Education is key to improvements in Africa's socioeconomic growth. Thus, Africa, is underpopulated in terms of potentiality but overpopulated in terms of reality, current conditions, and possibilities of overexploitation. Africa needs to invest in human resources. Families need to save, and to so, they must refrain from having many children. Africa should resist the temptation to waste, as rich countries do, and denounce it. Africa needs to become more independent of these countries, but structural adjustment plans, growing debt, and rapid population growth limit national independence. Food aid is a means for developed countries to dominate developing countries. Modernization through foreign aid has had some positive effects on developing countries (e.g., improved hygiene, mortality reduction), but these also sparked rapid population growth. Rwandan society is no longer traditional, but it is also not yet modern. A change in mentality to fewer births, better quality of life for living infants, better education, and less burden for women must occur

  19. Population vs. the environment.

    Science.gov (United States)

    1992-03-01

    In anticipation of UN Conference on Environment and Development scheduled for June in Brazil, the Japan Broadcasting Corporation (NHK) recently televised a hard-hitting documentary focusing on the impact of rapid population growth on resources and the environment. Entitled "Population Explosion and the Looming Crisis: Can Humankind Determine a Better Future?" the documentary aired on January 5, featuring interviews with experts from the population field such as Dr. Nafis Sadik of the UNFPA and Dr. Paul Ehrlich of Stanford University. The program, made with the cooperation of UNFPA and JOICFP, compared the current global demograhic and environmental situation with the one expected to exist in 2025, when the world population is expected to reach 10 billion. The documentary depicted a future fraught with food shortages, depleted energe resources, refugees, and a devastated environment. In order to illustrate the effect of population growth in developing countries, the documentary featured reports from countries in Asia and Africa. And to show the heavy burden that industrialized countries place on the global environment, the documentary examined Japan's own pattern of consumption and waste. As the UNFPA's Sadik pointed out, the luxurious lifestyle of developed countries comes at the expense of the developing world. Stressing that everyone in the world should be able to enjoy a reasonable standard of living. Sadik called for "sustainable patterns of development," which can be achieved through the following: improved technology, reduced consumption patterns, and changed lifestyles. A critical element in changing lifestyles includes reducing global fertility to 3.2 children/woman by the year 2000. Otherwise, a world population will not double but triple by the year 2025.

  20. Befolkningsudviklingen (Population Development)

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen

    2010-01-01

    The article takes the 1972 report, The Limits to Growth as its starting point, briefly explaining the Systam Dynamics model used for the report's analyses. Focus is on the important role of population. The simple model of I = PxAxT, where I is the environmental Impact, P population......, A is the Affluence and T the ecoimpact-intensity of the Technology used. Various scenarios ar shown, illustrating how a choice of 1.6 birth per woman on average instead of 2.6 birth, will in 2150 result in 3.6 billion people on earth instead of 27 billions. The article warns against the believe that growth in GDP...

  1. Africa population dynamics

    OpenAIRE

    Akinyoade, A.; Damen, J.C.M.; Dietz, A.J.; Kilama, B.B.; Omme, van, G.

    2014-01-01

    Africa's population has grown extremely rapidly over the last fifty years from 289 million inhabitants in 1961 to more than 1 billion today. This is a growth rate of 350% in just half a century and the number of urban residents has increased even more quickly: from 65 million in 1960 to 460 million today, or from 20% to 46% of the population as a whole. Demographers predict that soon more than 50% of all Africans will be living in cities. The average life expectancy, literacy rates and primar...

  2. Having quality population.

    Science.gov (United States)

    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

  3. Constructing populations in biobanking

    DEFF Research Database (Denmark)

    Tupasela, Aaro; Snell, Karoliina; Cañada, Jose a.

    2015-01-01

    This article poses the question of whether biobanking practices and standards are giving rise to the construction of populations from which various biobanking initiatives increasingly draw on for legitimacy? We argue that although recent biobanking policies encourage various forms of engagement w...

  4. Population and Development Issues.

    Science.gov (United States)

    Cohen, Sharon; Garran, Christopher

    1998-01-01

    Describes a unit on demographics for a high school world-history course that addresses questions of uneven population growth and the "problem of global overpopulation." Provides a detailed outline of the two-day unit including unit and daily goals and objectives, daily activities and questions, and ideas for further student research. (DSK)

  5. Population: fiction and fact.

    Science.gov (United States)

    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.

  6. Population, food and knowledge

    DEFF Research Database (Denmark)

    Strulik, Holger; Weisdorf, Jacob Louis

    2008-01-01

    of population. London, printed for J. Johnson, 1798) so-called preventive check hypothesis-that fertility rates vary inversely with the price of food-the current study offers a new and straightforward explanation for the demographic transition and the break with the Malthusian era. Employing a two...

  7. [Population trends and poverty].

    Science.gov (United States)

    Olmedo, C

    1998-04-01

    Implications of population growth in Ecuador for the quality of life of the poor population are analyzed. It is argued that if the gross national product (GNP) were to grow at a sustained annual rate of 5% or more, demographic trends would not present a significant obstacle to reducing poverty. National economic projections are for growth of only 2.5-3.5% annually. The continuing rapid growth of the poor population despite general slowing of demographic growth, the young age structure, the need for increased formal education to enable the poor to overcome their poverty, and the effect of unemployment on the dependency ratio will tend to hamper improvements in average productivity and per capita GNP. The need for spending on education, health, basic services, and housing will divert funds away from productive investment, generating a direct negative impact on economic growth. Over half of Ecuadorian children suffer from some degree of malnutrition, indicating that food production is inadequate to meet demand. The export-oriented agricultural policy and poor weather have led to a chronic shortage of basic foods. Progressive increase and diversification of agricultural production, along with maintenance of low prices and substantial increases in income levels and agricultural productivity, will be required if the entire population is to be fed adequately. Intense efforts will be needed from all sectors to bring demographic growth into balance with economic and development needs.

  8. (Hyperolius marmoratus) populations

    African Journals Online (AJOL)

    population differentiation among ..... 13: 121-177. RICHARDS. C.M. & MOORE. W.S. 1996. A phylogeny for the. African tree frog family Ilyperoliidne based on mitochondrial. rONA. Mol. Phyl. Evol. 5(3): 522-532. SELANDER. R.K. & KAlJFMAN.

  9. [Population and development].

    Science.gov (United States)

    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.

  10. Africa population dynamics

    NARCIS (Netherlands)

    Akinyoade, A.; Damen, J.C.M.; Dietz, A.J.; Kilama, B.B.; Omme, van G.

    2014-01-01

    Africa's population has grown extremely rapidly over the last fifty years from 289 million inhabitants in 1961 to more than 1 billion today. This is a growth rate of 350% in just half a century and the number of urban residents has increased even more quickly: from 65 million in 1960 to 460 million

  11. Ideology and population theory.

    Science.gov (United States)

    Harvey, D

    1974-01-01

    The ideological and ethical foundations of population theory are examined in the light of the supposed eithical neutrality of scientific enquiry. The works of Malthus, Ricardo, and Marx are contrasted and it is shown that their theories of population resulted in each case from the adoption of a particular kind of method--empiricism in Malthus, normative analytic "model building" in Ricardo, and dialectical materialism in Marx. It is shown that a Malthusian or neo-Malthusian view of the population problem is inevitable if enquiry is founded in empiricism or in normative analytics. The well-known disagreement between Malthusian and Marxian viewpoints therefore has its foundation in method. Most modern enquiry into the population-resources problem is dominated by empirical and analytic (including systems theory) approaches and consequently arrives at neo-Malthusian conclusions. The final section analyses the consequences of adopting a neo-Malthusian view, and it is shown that in a world dominated by an elite, this can frequently bring about the political, social, and economic repression of a non-elite. It is concluded that the choice of scientific method does not produce unbiased results and that the dominance of a certain conception of scientific method leads to the scientific support of a viewpoint used to justify repression of the underprivileged in society.

  12. Probabilistic population aging.

    Science.gov (United States)

    Sanderson, Warren C; Scherbov, Sergei; Gerland, Patrick

    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.

  13. Effect of unsampled populations on the estimation of population sizes and migration rates between sampled populations.

    Science.gov (United States)

    Beerli, Peter

    2004-04-01

    Current estimators of gene flow come in two methods; those that estimate parameters assuming that the populations investigated are a small random sample of a large number of populations and those that assume that all populations were sampled. Maximum likelihood or Bayesian approaches that estimate the migration rates and population sizes directly using coalescent theory can easily accommodate datasets that contain a population that has no data, a so-called 'ghost' population. This manipulation allows us to explore the effects of missing populations on the estimation of population sizes and migration rates between two specific populations. The biases of the inferred population parameters depend on the magnitude of the migration rate from the unknown populations. The effects on the population sizes are larger than the effects on the migration rates. The more immigrants from the unknown populations that are arriving in the sample populations the larger the estimated population sizes. Taking into account a ghost population improves or at least does not harm the estimation of population sizes. Estimates of the scaled migration rate M (migration rate per generation divided by the mutation rate per generation) are fairly robust as long as migration rates from the unknown populations are not huge. The inclusion of a ghost population does not improve the estimation of the migration rate M; when the migration rates are estimated as the number of immigrants Nm then a ghost population improves the estimates because of its effect on population size estimation. It seems that for 'real world' analyses one should carefully choose which populations to sample, but there is no need to sample every population in the neighbourhood of a population of interest.

  14. A population of hematopoietic stem cells derives from GATA4-expressing progenitors located in the placenta and lateral mesoderm of mice.

    Science.gov (United States)

    Cañete, Ana; Carmona, Rita; Ariza, Laura; Sánchez, María José; Rojas, Anabel; Muñoz-Chápuli, Ramón

    2017-04-01

    GATA transcription factors are expressed in the mesoderm and endoderm during development. GATA1-3, but not GATA4, are critically involved in hematopoiesis. An enhancer (G2) of the mouse Gata4 gene directs its expression throughout the lateral mesoderm and the allantois, beginning at embryonic day 7.5, becoming restricted to the septum transversum by embryonic day 10.5, and disappearing by midgestation. We have studied the developmental fate of the G2-Gata4 cell lineage using a G2-Gata4 Cre ;R26R EYFP mouse line. We found a substantial number of YFP + hematopoietic cells of lymphoid, myeloid and erythroid lineages in embryos. Fetal CD41 + /cKit + /CD34 + and Lin - /cKit + /CD31 + YFP + hematopoietic progenitors were much more abundant in the placenta than in the aorta-gonad-mesonephros area. They were clonogenic in the MethoCult assay and fully reconstituted hematopoiesis in myeloablated mice. YFP + cells represented about 20% of the hematopoietic system of adult mice. Adult YFP + hematopoietic stem cells constituted a long-term repopulating, transplantable population. Thus, a lineage of adult hematopoietic stem cells is characterized by the expression of GATA4 in their embryonic progenitors and probably by its extraembryonic (placental) origin, although GATA4 appeared not to be required for hematopoietic stem cell differentiation. Both lineages basically showed similar physiological behavior in normal mice, but clinically relevant properties of this particular hematopoietic stem cell population should be checked in physiopathological conditions. Copyright© Ferrata Storti Foundation.

  15. The population explodes.

    Science.gov (United States)

    Hickcox, S

    1999-01-01

    This letter to the editor refers to an article on the "Baby Boom" published in 1998. The letter notes that no consensus exists among environmentalists about population growth or abortion and calls for more balance in coverage of these issues. The letter points out that, in animal and human populations, a "natural" suppression of reproduction occurs in the presence of a stable ecosystem. However, humans have forever changed the delicate balance of earth's ecosystems. The letter offers China as an example of a country whose drive to become an industrialized power is causing overuse, neglect, and destruction of natural resources. The letter concludes that efforts to obtain sustainability should involve a "more sobering look at free enterprise and the global economy."

  16. On optimal population paths

    CERN Document Server

    Lane, John S

    1977-01-01

    The overall purpose of this monograph is to integrate and critically evaluate the existing literature in the area of optimal joint savings population programs. The existing diverse presentations are all seen to be discussions within a unified framework. The central problem is to compare the desirability of alternative inter-temporal sequences of total savings and population sizes. Of critical importance is whether one regards persons as the fundamental moral entities or whether one takes Sidgwick's viewpoint that something good being the result of one's action is the baSic reason for dOing anything. The latter viewpoint is consistent with defining a complete social preference ordering over these alternative sequences. Since part of one's interest is to evaluate the consequences of various ethical beliefs a com­ parative study of several such orderings is presented; in particular the Mill-Wolfe average utilitarian, and Sidgwick-Meade classical utilitarian) formulations. A possible problem with the social pref...

  17. Cancer among circumpolar populations

    DEFF Research Database (Denmark)

    Young, T Kue; Kelly, Janet J; Friborg, Jeppe

    2016-01-01

    OBJECTIVES: To determine and compare the incidence of cancer among the 8 Arctic States and their northern regions, with special focus on 3 cross-national indigenous groups--Inuit, Athabaskan Indians and Sami. METHODS: Data were extracted from national and regional statistical agencies and cancer...... registries, with direct age-standardization of rates to the world standard population. For comparison, the "world average" rates as reported in the GLOBOCAN database were used. FINDINGS: Age-standardized incidence rates by cancer sites were computed for the 8 Arctic States and 20 of their northern regions......, averaged over the decade 2000-2009. Cancer of the lung and colon/rectum in both sexes are the commonest in most populations. We combined the Inuit from Alaska, Northwest Territories, Nunavut and Greenland into a "Circumpolar Inuit" group and tracked cancer trends over four 5-year periods from 1989 to 2008...

  18. Populism and the media

    DEFF Research Database (Denmark)

    Esser, Frank; Stepinska, Agnieszka; Hopmann, David Nicolas

    2017-01-01

    /click” with a broad audience. As was stated in Chapter 1 in this volume, the role that the media play in the dissemination of populism is largely under-explored. In the classical research literature dealing with populism (see, e.g., Canovan, 1981; Taggart, 2000), communication and media are not addressed at all. When...... political scientists make the media their subject, they see the media mostly only as a neutral platform for populist leaders’ appearances and messages. One exception is Mudde (2007), who dedicates at least a few pages to this topic in his book Populist Radical Right Parties in Europe (pp. 248-253). He......European media systems have gone through major changes in the last few decades, and these changes have included increased opportunity structures for the dissemination of populist messages. Chapter 12 (‘Switzerland’) rightly states that the disappearance of the traditional party press, increased...

  19. [Population, ethics and equity].

    Science.gov (United States)

    Berlinguer, G

    1997-01-01

    "Demography is, explicitly and not, imbued with an [ethical] content.... As demography involves both public policies and individual choices, the [ethical] slant should be [examined]. Thus, what we have on the one hand is an [ethical] state, which dictates its citizens' personal behaviour and, on the other, a state based on liberty, backed up by three shared values: human rights, pluralism and equality. This article looks at how today these may be reinterpreted when making decisions regarding the population." (EXCERPT)

  20. Fertility and Population Policy

    OpenAIRE

    Ouedraogo, Abdoulaye; Tosun, Mehmet S.; Yang, Jingjing

    2018-01-01

    There have been significant changes in both the fertility rates and fertility perception since 1970s. In this paper, we examine the relationship between government policies towards fertility and the fertility trends. Total fertility rate, defined as the number of children per woman, is used as the main fertility trend variable. We use panel data from the United Nations World Population Policies database, and the World Bank World Development Indicators for the period 1976 through 2013. We find...

  1. Population, environment and development.

    Science.gov (United States)

    Karkal, M

    1994-06-01

    Western development models label subsistence economies, which do not participate in the market economy on a grand scale and do not consume commodities produced for and distributed through the market, to be poor. Yet, subsistence does not always indicate a low quality of life. The Western development process has destroyed wholesome and sustainable lifestyles. In India, the Green Revolution caused many small farmers to lose their land. In comparison to traditional economies, industrial economies have longer technological chains dependent on higher energy and resource inputs and exclude large numbers of people without power to buy goods. Further, they generate new and artificial needs, necessitating increased production of industrial goods and services. They erode resource bases for survival. This erosion is marginalizing people who were traditionally in nature's economy. Developed countries did not deliver 0.15% of their GNP to development projects in developing countries as promised. The US made population growth in these countries its cause. The UN and other multinational agencies during 1962-1972, at the US's request, began to support population and family planning programs in developing countries. These countries opposed the 1st draft at the 1974 Bucharest Population Conference, but by the conference in Mexico City, most supported the need for family planning. Yet, the US politicized this conference and had a greater say in the recommendations than did developing countries. Structural adjustments and external debt repayments required of developing countries in the 1980s set them back. In fact, the number of developing countries increased from 31 to 42. The UN recognizes the right to development, but social inequalities are barriers to this right. If environmental degradation continues, poverty will only increase. Women's groups are playing a great role in preparations for the International Conference on Population and Development in Cairo in September 1994.

  2. Globalisation, Inequality and Populism

    OpenAIRE

    Nolan, Brian

    2017-01-01

    read before the Society, 20 April 2017; Symposium 2016-2017: Globalisation, Inequality and the Rise of Populism Inequality in the distribution of income and wealth among individuals has now come to the fore as a core concern across the industrialised world. In 2013 then President of the United States Barack Obama identified rising income inequality as ?the defining challenge of our times?. The Managing Director of the International Monetary Fund Christine Lagarde has stated that ?reducing ...

  3. Population, desertification, and migration.

    Science.gov (United States)

    Westing, A H

    1994-01-01

    When an imbalance develops between population numbers and the carrying capacity of the land, the persons thereby displaced are referred to as environmental refugees. The utilization of the land beyond sustainability leads to land degradation and ultimately, desertification. The social and political impacts of long-term environmental migration can be distinguished: a) at the site of origin of the displaced persons by the residual population; b) at rural sites of destination within the nation between the new arrivals and preestablished populations; c) in the cities within the nation; d) in the nonindustrialized foreign countries; and e) in the industrialized foreign countries. In the event that an area which had previously been devoted to pastoralism is converted to agriculture, the displaced pastoralists might respond through armed rebellion. In some instances, the disenchanted urban squatters become a politically restive and even a destabilizing force, as occurred in Sudan in the 1980s, especially in Khartoum and Port Sudan. The foreign countries to which many of the displaced persons are migrating are subjected to increasing levels of migrant-induced economic, cultural, and political strains. The growing problems associated with south-to-north migration across the Mediterranean Sea have recently led France, Italy, Portugal, and Spain to enter into a consultative arrangement with Algeria, Libya, Mauritania, Morocco, and Tunisia. All foreign aid to the nonindustrialized countries that attempts to ameliorate the problem of desertification must adopt integrated approaches that: a) address population issues; b) support environmental education; c) provide for the protection of biodiversity; d) encourage participatory forms of local and national government; e) provide opportunities for income generation outside the livestock sector; and f) foster political security and facilitate ecogeographical (subregional) cooperation.

  4. Target population growth: zero.

    Science.gov (United States)

    2000-02-01

    The Fifth Session of the Fourth National Council of the China Family Planning Association held in Beijing on December 13, 1999, focused on how to control the number of people in China and improve their quality of life. Family planners also explored ways to decrease the number of babies with birth defects and maternal mortality rate. During the meeting, Zhang Weiqing, minister of the State Family Planning Commission, expressed that they are optimistic about keeping the Chinese population under 1.3 billion before the 21st century. He added that top attention should be paid to providing family planning service (sexual and reproductive counseling) for unmarried young people, laid-off workers, and the transient population in urban areas. In Shenzhen, a special economic zone, 854 family planning offices have been established among 2.8 million temporary residents, these agencies, many of which are led by temporary residents themselves. Lastly, Zhang announced that a draft national law on population and family planning has been finished and the law is expected to be enacted in 3 years.

  5. Food and population.

    Science.gov (United States)

    1985-04-06

    Agricultural producttivity is currently characterized by the paradox of an abundace of food in the developed world and hunger in much of the developing world. In China, India, and many other countries of Asia, the general food supply has kept pace with population growth and should continue to if family planning programs gain momentum. In Africa, on the other hand, the food supply has been falling behind the growth of the population in the majority of countries for the past decade. The situation is especially serious in the Sahel, where the production wf crops for export has been prioritized over local needs. The Food and Agriculture Organization's global information and early warning system is a promising development and can provide alerts when weather or other conditions threaten a harvest. Donor countries can then send in cereals and other foods before there is an actual famine. About 20 disasters in the Sahel are etimated to have been averted by this system, in operation since 1975. In developed countries, the farming industry needs to be restructured in relation to changes in markets and technologies. Solution of the food-population problem depends upon agricultural policies that balance the economic interests of farmers and consumers and also takes into account the need to preserve the countryside.

  6. The population factor.

    Science.gov (United States)

    Kats, G

    1983-01-01

    Reducing population growth is essentil to Egypt's broader efforts to improve facilities, services, and the phsycial quality of life. Although a family planning program has existed since the mid-1950s, the 2.7% annual rate of population growth has not changed in 30 years. Nasser and the other "free officers" who seized power in 1952 became concerned about the adverse effects of the rapidly growing population, but perhaps out of concern with a possible religious backlash, they confined themselves to launching studies and subsidizing several dozen private family planning clinics. From 1962-72, the number of private clinics grew from 28 to 480, and family planning was introduced in government healthclinics in 1965. Such clinics are mainly located in rural areas and are staffed by doctors and other personnel who are not members of the local community and are not very effective at promoting family planning. Local girls and women called Rayadet were recruited to promote the idea to birth control in local communities. By 1970, 12.6% of Egyptians were using reliable contraception. A national survey 12 years later found 34% using contraception, buth the figure seems high. Approximately 60-65% of eligible couples would need to practice birth control for Egypt to reach a less than 1% annuel increase. The Egyptian government hopes to slow population growth to 1% by the year 2000, but major problems of motivation remain especially among the rural poor. Several factors may lead to success of the family planning effort: 1) financial and technical support from international family planning sources has grown rapidley and is likely to remain high; 2) the mortality rate has dropped from 17.8/1000 in 1952 to about half that level, while the rate of natural increase is about the same, suggesting that future reductions in the birth rate will translate to a reduced rate of natural increase, and that parents will be less reluctant to practice faimly planning if there is a greater chance

  7. Population and climate change.

    Science.gov (United States)

    Cohen, Joel E

    2010-06-01

    To review, the four broad dimensions of any complex human problem, including climate change, are the human population, economics, culture, and environment. These dimensions interact with one another in all directions and on many time-scales. From 2010 to 2050, the human population is likely to grow bigger, more slowly, older, and more urban. It is projected that by 2050 more than 2.6 billion people (almost 94% of global urban growth) will be added to the urban population in today's developing countries. That works out to 1.26 million additional urban people in today's developing countries every week from 2010 to 2050. Humans alter the climate by emitting greenhouse gases, by altering planetary albedo, and by altering atmospheric components. Between 1900 and 2000, humans' emissions of carbon into the atmosphere increased fifteenfold, while the numbers of people increased less than fourfold. Population growth alone, with constant rates of emissions per person, could not account for the increase in the carbon emissions to the atmosphere. The world economy grew sixteenfold in the twentieth century, accompanied by enormous increases in the burning of gas, oil, and coal. In the last quarter of the twentieth century, population grew much faster in developing countries than in high-income countries, and, compared with population growth, the growth of carbon emissions to the atmosphere was even faster in developing countries than in high-income countries. The ratio of emissions-to-population growth rates was 2.8 in developing countries compared with 1.6 in high-income countries. Emissions of CO2 and other greenhouse gases are influenced by the sizes and density of settlements, the sizes of households, and the ages of householders. Between 2010 and 2050, these demographic factors are anticipated to change substantially. Therefore demography will play a substantial role in the dynamics of climate changes. Climate changes affect many aspects of the living environment

  8. Population Growth and National Population Policy of India

    Science.gov (United States)

    Thukral, A. K.; Singh, B. P.

    2008-01-01

    The population growth in India may overtake China by the year 2030. The National Population Policy of India targets population stabilization in India by the year 2045. The present paper carries out objective analysis of the population growth in India in terms of change in specific growth. At the present rate of specific growth rate decline, the population by the end of the century will be 2.49 billion. For the population to achieve zero growth by the year 2045, a decline in specific growth rate will have to be achieved at the rate of 0.000428 per year.

  9. Population policies and development.

    Science.gov (United States)

    Stamper, B M

    1984-01-01

    This article critically examines 4 conceptual frameworks for Third World population policies: the family planning approach, beyond family planning measures, the development hypothesis and transition theory, and the distributive hypothesis and fertility. Although family planning is a basic human right and can lead to lower levels of population and improved maternal-child health, this approach alone does not always have a meaningful demographic impact. If high fertility is economically rational from the family viewpoint, the demand for family planning services will remain marginal. Other policies seek to go beyond the family planning approach and to directly influence the demand for reproductive control through provision of old age support, monetary incentives for reduced fertility or stringent and coercive measures. However, such policies can have adverse distributional effects and directly penalize the children of large families. The demographic transition theory lacks a measurable and specifiable causation mechanism, giving it little predictive value. It may be that economic growth increases fertility in the short run and reduces fertility only over the long run through indirect effects. The key issue is how the rate of growth is distributed across the population. The development and demographic transition hypothesis focuses mainly on aggregate economic and social measures rather than on their underlying distributions. The distributive hypothesis implies policies that promote a greater level of investment in human capital, with a wide distributional emphasis. Diffused investment in human capital is believed to indirectly influence the desire to control fertility. It is concluded that all 4 conceptual frameworks for analyzing fertility-related policies for the Third World are inadequate or seriously flawed. They are not pragmatic, do not identify or assign weights to the crucial causal variables, fail to specify thresholds or critical minimum levels, discount

  10. High population increase rates.

    Science.gov (United States)

    1991-09-01

    In addition to its economic and ethnic difficulties, the USSR faces several pressing demographic problems, including high population increase rates in several of its constituent republics. It has now become clear that although the country's rigid centralized planning succeeded in covering the basic needs of people, it did not lead to welfare growth. Since the 1970s, the Soviet economy has remained sluggish, which as led to increase in the death and birth rates. Furthermore, the ideology that held that demography could be entirely controlled by the country's political and economic system is contradicted by current Soviet reality, which shows that religion and ethnicity also play a significant role in demographic dynamics. Currently, Soviet republics fall under 2 categories--areas with high or low natural population increase rates. Republics with low rates consist of Christian populations (Armenia, Moldavia, Georgia, Byelorussia, Russia, Lithuania, Estonia, Latvia, Ukraine), while republics with high rates are Muslim (Tadzhikistan, Uzbekistan, Turkmenistan, Kirgizia, Azerbaijan Kazakhstan). The later group has natural increase rates as high as 3.3%. Although the USSR as a whole is not considered a developing country, the later group of republics fit the description of the UNFPA's priority list. Another serious demographic issue facing the USSR is its extremely high rate of abortion. This is especially true in the republics of low birth rates, where up to 60% of all pregnancies are terminated by induced abortions. Up to 1/5 of the USSR's annual health care budget is spent on clinical abortions -- money which could be better spent on the production of contraceptives. Along with the recent political and economic changes, the USSR is now eager to deal with its demographic problems.

  11. Hidden ion population: Revisited

    International Nuclear Information System (INIS)

    Olsen, R.C.; Chappell, C.R.; Gallagher, D.L.; Green, J.L.; Gurnett, D.A.

    1985-01-01

    Satellite potentials in the outer plasmasphere range from near zero to +5 to +10 V. Under such conditions ion measurements may not include the low energy core of the plasma population. In eclipse, the photoelectron current drops to zero, and the spacecraft potential can drop to near zero volts. In regions where the ambient plasma density is below 100 cm -3 , previously unobserved portions of the ambient plasma distribution function can become visible in eclipse. A survey of the data obtained from the retarding ion mass spectrometer (RIMS) on Dynamics Explorer 1 shows that the RIMS detector generally measured the isotropic background in both sunlight and eclipse in the plasma-sphere. Absolute density measurements for the ''hidden'' ion population are obtained for the first time using the plasma wave instrument observations of the upper hybrid resonance. Agreement in total density is found in sunlight and eclipse measurements at densities above 80 cm -3 . In eclipse, agreement is found at densities as low as 20 cm -3 . The isotropic plasma composition is primarily H + , with approx.10% He + , and 0.1 to 1.0% O + . A low energy field-aligned ion population appears in eclipse measurements outside the plasmasphere, which is obscured in sunlight. These field-aligned ions can be interpreted as field-aligned flows with densities of a few particles per cubic centimeter, flowing at 5-20 km/s. The problem in measuring these field-aligned flows in sunlight is the masking of the high energy tail of the field-aligned distribution by the isotropic background. Effective measurement of the core of the magnetospheric plasma distribution awaits satellites with active means of controlling the satellite potential

  12. Diabetes in population isolates

    DEFF Research Database (Denmark)

    Grarup, Niels; Moltke, Ida; Albrechtsen, Anders

    2015-01-01

    Type 2 diabetes (T2D) is an increasing health problem worldwide with particularly high occurrence in specific subpopulations and ancestry groups. The high prevalence of T2D is caused both by changes in lifestyle and genetic predisposition. A large number of studies have sought to identify...... on glucose-stimulated plasma glucose, serum insulin levels, and T2D. The variant defines a specific subtype of non-autoimmune diabetes characterized by decreased post-prandial glucose uptake and muscular insulin resistance. These and other recent findings in population isolates illustrate the value...

  13. Playing With Population Protocols

    Directory of Open Access Journals (Sweden)

    Xavier Koegler

    2009-06-01

    Full Text Available Population protocols have been introduced as a model of sensor networks consisting of very limited mobile agents with no control over their own movement: A collection of anonymous agents, modeled by finite automata, interact in pairs according to some rules. Predicates on the initial configurations that can be computed by such protocols have been characterized under several hypotheses. We discuss here whether and when the rules of interactions between agents can be seen as a game from game theory. We do so by discussing several basic protocols.

  14. [Several problems concerning population investment].

    Science.gov (United States)

    Liu, Z

    1982-07-29

    Population investment is a major topic in the studies of population and economic relations. In this particular area, numerous theoretical and practical problems are still in need of solution. Concerning the problem of population concept, there are three different approaches: (1) to determine the definition of population investment from the relationship between the population growth and the capital from national income used for investment, including investment in the newly increased population and investment in the entire population; (2) to explain population investment from the economic viewpoint that people are producers; and (3) to explain population investment from the expense needed to change a simple labor force to a skillful labor force. The expenses include educational costs, maintanance spending, wages needed to compensate workers in labor, costs for workers to master and learn modern scientific techniques to be used for production, and the costs of keeping a young labor force in the next generation.

  15. Genetic changeover in Drosophila populations

    International Nuclear Information System (INIS)

    Wallace, B.

    1986-01-01

    Three populations of Drosophila melanogaster that were daughter populations of two others with histories of high, continuous radiation exposure [population 5 (irradiated, small population size) gave rise to populations 17 (small) and 18 (large); population 6 (irradiated, large population size) gave rise to population 19 (large)] were maintained for 1 year with no radiation exposure. The frequency with which random combinations of second chromosomes taken from population 19 proved to be lethal changed abruptly after about 8 months, thus revealing the origin of a selectively favored element in that population. (This element may or may not have been the cause of the lethality.) A comparison of the loss of lethals in populations 17 and 18 with a loss that occurred concurrently in the still-irradiated population 5 suggests that a second, selectively favored element had arisen in that population just before populations 17 and 18 were split off. This element was on a nonlethal chromosome. The result in population 5 was the elimination of many lethals from that population, followed by a subsequent increase as mutations occurred in the favored nonlethal chromosome. Populations 17 and 18, with no radiation exposure, underwent a loss of lethals with no subsequent increase. The events described here, as well as others to be described elsewhere, suggest that populations may be subject to episodic periods of rapid gene frequency changes that occur under intense selection pressure. In the instances in which the changeover was revealed by the elimination of preexisting lethals, earlier lethal frequencies were reduced by approximately one-half; the selectively favored elements appear, then, to be favored in the heterozygous--not homozygous--condition

  16. Population dynamics and biology of an invasive population of ...

    African Journals Online (AJOL)

    Population dynamics and biology of an invasive population of mosquitofish Gambusia affinis in a temperate estuarine lake system. Hans Sloterdijk, Nicola C. James, M Kyle S. Smith, Werner Ekau, Olaf L.F. Weyl ...

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

    Science.gov (United States)

    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.

  18. Population's political clout.

    Science.gov (United States)

    Schima, M E; Viel, B; Chen, P C; Gille, H; Epstein, S G

    1980-03-01

    China's birth planning program has its own separate administrative hierarchy. The political commitment to population planning which originates with the top leadership extends to peer pressure exerted on couples at the brigade and neighborhood level. While family planning services are primarily delivered in health structures, responsibility for the population program falls to the Leading Group on Birth Planning. Not only health officials but also officials responsible for economic planning, political propaganda, scientific research, trade unions, women's affairs, and all those whose participation is considered necessary to the program's success attend meeting. The Leading Group on Birth Planning is chaired by a Vice-Premier. At each administrative level, provincial to work brigade, the same pattern is repeated: centralized responsibility combined with broad representation and high-level potitical leadership. With a tight, working structure, China has been able to enact its birth control program with remarkable speed and effectiveness. Each production brigade has its own planned birth leading group headed by the captain of the brigade or the captain of the women's team. The leading group supervises the barefoot doctors, midwives, and team level health aides who deliver contraceptives to households or accompany people to the community health center to obtain surgical services.

  19. The aging population in Brazil

    Directory of Open Access Journals (Sweden)

    Fabio Nasri

    2008-03-01

    Full Text Available Brazil is currently in an advanced stage of both the mortality andfertility transitions, which allows one to confi dently forecast the agedistribution and population size over the next four decades. Whereasthe elderly population with more than 65 years will increase at highrates (2 to 4% per year the young population will decline. Accordingto United Nations projections, the elderly population will increasefrom 3.1% of the population in 1970 to 19% in 2050. The changingage distribution of the Brazilian population brings opportunities andchallenges that could lead to serious social and economic issues ifnot dealt with properly in coming decades.

  20. Density Estimation in Several Populations With Uncertain Population Membership

    KAUST Repository

    Ma, Yanyuan

    2011-09-01

    We devise methods to estimate probability density functions of several populations using observations with uncertain population membership, meaning from which population an observation comes is unknown. The probability of an observation being sampled from any given population can be calculated. We develop general estimation procedures and bandwidth selection methods for our setting. We establish large-sample properties and study finite-sample performance using simulation studies. We illustrate our methods with data from a nutrition study.

  1. Population Trends and the Status of Population Policy in Africa.

    Science.gov (United States)

    Rogge, John R.

    1982-01-01

    The major trend towards worldwide easing of the birthrate does not include the current population patterns in Africa. The population policies of African nations range along a continuum from totally pronatal to strongly antinatal. However, even antinatal policies have had little effect on the overall spiralling upward population trend. (JA)

  2. Population, migration and urbanization.

    Science.gov (United States)

    1982-06-01

    Despite recent estimates that natural increase is becoming a more important component of urban growth than rural urban transfer (excess of inmigrants over outmigrants), the share of migration in the total population growth has been consistently increasing in both developed and developing countries. From a demographic perspective, the migration process involves 3 elements: an area of origin which the mover leaves and where he or she is considered an outmigrant; the destination or place of inmigration; and the period over which migration is measured. The 2 basic types of migration are internal and international. Internal migration consists of rural to urban migration, urban to urban migration, rural to rural migration, and urban to rural migration. Among these 4 types of migration various patterns or processes are followed. Migration may be direct when the migrant moves directly from the village to the city and stays there permanently. It can be circular migration, meaning that the migrant moves to the city when it is not planting season and returns to the village when he is needed on the farm. In stage migration the migrant makes a series of moves, each to a city closer to the largest or fastest growing city. Temporary migration may be 1 time or cyclical. The most dominant pattern of internal migration is rural urban. The contribution of migration to urbanization is evident. For example, the rapid urbanization and increase in urban growth from 1960-70 in the Republic of Korea can be attributed to net migration. In Asia the largest component of the population movement consists of individuals and groups moving from 1 rural location to another. Recently, because urban centers could no longer absorb the growing number of migrants from other places, there has been increased interest in the urban to rural population redistribution. This reverse migration also has come about due to slower rates of employment growth in the urban centers and improved economic opportunities

  3. CDC WONDER: Population (from Census)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Population online databases contain data from the US Census Bureau. The Census Estimates online database contains contains county-level population counts for...

  4. NASA Orbital Debris Baseline Populations

    Science.gov (United States)

    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. Millennium Ecosystem Assessment: MA Population

    Data.gov (United States)

    National Aeronautics and Space Administration — The Millennium Ecosystem Assessment: MA Population data sets provide baseline population information as one of the drivers of ecosystem change. The data helped in...

  6. Stochastic population theories

    CERN Document Server

    Ludwig, Donald

    1974-01-01

    These notes serve as an introduction to stochastic theories which are useful in population biology; they are based on a course given at the Courant Institute, New York, in the Spring of 1974. In order to make the material. accessible to a wide audience, it is assumed that the reader has only a slight acquaintance with probability theory and differential equations. The more sophisticated topics, such as the qualitative behavior of nonlinear models, are approached through a succession of simpler problems. Emphasis is placed upon intuitive interpretations, rather than upon formal proofs. In most cases, the reader is referred elsewhere for a rigorous development. On the other hand, an attempt has been made to treat simple, useful models in some detail. Thus these notes complement the existing mathematical literature, and there appears to be little duplication of existing works. The authors are indebted to Miss Jeanette Figueroa for her beautiful and speedy typing of this work. The research was supported by the Na...

  7. [[Population and industrial development

    Science.gov (United States)

    Charoenloet, V

    "Concurrent with the decline in population growth rate in the 1980s, Thailand experienced an unprecedented rate of economic growth....Such phenomenal economic growth has generally been attributed to the internationalization of the Thai economy through the rapid expansion of exports, foreign investment and tourism. However, industries in the manufacturing sector...tend to be resource-based and labour-intensive. Moreover, foreign investment in export-oriented industries tends to use Thailand as a base for assembling rather than producing goods and has been attracted primarily by cheap labour cost. All these may contribute to the employment of [a] nonskilled, lowly-paid labour force, but not the development of scientific/technology based industries, the foundation for permanent and lasting economic development." (SUMMARY IN ENG) excerpt

  8. [Excessive population and health].

    Science.gov (United States)

    Rivera, A A

    1995-07-01

    Population density in El Salvador is among the highest in the world. In metropolitan San Salvador and the other main cities, crowding, squatter settlements, unemployment and underemployment, scarcity of basic services, squalor, and other social pathologies appear to be increasing. Overpopulation poses an enormous challenge for development. Reflection on the benefits of family planning has been delayed in El Salvador, and in the interim there have been increases in social inequality, misery, and hunger. Family planning programs have been referred to as "neo-Malthusian" and contrary to the right to life, but in fact they promote birth spacing and free selection of methods by couples, contributing to improvement in the quality of family life. Family planning allows couples to limit their offspring to those they can adequately care for emotionally and materially. People must be shown that family planning alleviates many of humanity's problems.

  9. Refining population health comparisons

    DEFF Research Database (Denmark)

    Hussain, M. Azhar; Jørgensen, Mette Møller; Østerdal, Lars Peter Raahave

    2016-01-01

    How to determine if a population group has better overall (multidimensional) health status than another is a central question in the health and social sciences. We apply a multidimensional first order dominance concept that does not rely on assumptions about the relative importance of each...... dimension. In particular, we show how one can explore the “depth” of dominance relations by gradually refining the health dimensions to see which dominance relations persist. We analyze a Danish health survey with many health indicators. These are initially collapsed into a single composite health dimension...... and then refined to four, seven, and ten health dimensions, each representing an (increasingly refined) area of health. Overall we find that younger age groups dominate older age groups in up to four dimensions, but no dominance relations are present with a more refined view of health. Comparing education groups...

  10. Population, environment, and development.

    Science.gov (United States)

    Myers, N

    1993-01-01

    The strategies for reducing population growth include social development and improvement in the educational attainment of women. The decline in Kenya's growth rate was attributed to high female literacy and reduced infant mortality. Another strategy for enhancing fertility decline is to reduce child mortality, particularly from preventable causes such as diarrhea. The entire cost of such a strategy to reduce preventable disease would be about $1.33 per 300 million taxpayers in developed countries. Family planning services must be expanded. Prevention of maternal mortality and AIDS would bring major benefits. Strategies for environmental protection emphasized the already existing plan of action set out in the UNCED document Agenda 21 in Rio de Janeiro. The plan has suffered from inaction. The estimated cost of $625 million was considered to be several times smaller than the costs of inaction. The elimination of subsidies in tropical forests would have an immediate impact. Natural resource accounting at the national level would include the value of natural resources. Pricing would change radically for gasoline if the costs of urban smog, acid rain, low-level ozone pollution, and global warming were taken into account. Strategies for sustainable development pertained to the preceding strategies and others indicated in the Agenda 21 Action Plan. If funding were better targeted to the poorest 20% of global population with high fertility rates, the accomplishments would be heralded. 1.2 million are living in absolute poverty, and aid for nutrition, primary health care, water and sanitation, basic education, and family planning amounts to only 10% of expenditures. An increase to 20% would mean a contribution from Americans of $7.50 per person or 33% of $25 thousand million from all developed countries. Developing countries need to lower their military expenditures, privatize public enterprises, change inappropriate development policies, eliminate corruption, and improve

  11. A Population of Assessment Tasks

    Science.gov (United States)

    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."

  12. Population genetics without intraspecific data

    DEFF Research Database (Denmark)

    Thorne, Jeffrey L; Choi, Sang Chul; Yu, Jiaye

    2007-01-01

    populations, and parameters of interspecific models should have population genetic interpretations. We show, with two examples, how population genetic interpretations can be assigned to evolutionary models. The first example considers the impact of RNA secondary structure on sequence change, and the second...... genetic interpretation. Udgivelsesdato: 2007-Aug...

  13. [Population ethics and growth].

    Science.gov (United States)

    Boim, D

    1988-01-01

    In order to formulate and implement a national demographic policy, various areas of science are called upon; however, since human lives are involved, ethical aspects play an important role not only in broad ideological terms, e.g, concerning overpopulation, but whenever practical decisions affecting technology and human resources are made. The article describes how the Catholic Church proposes certain "utopian" views or interpretations as part of an ethical "dynamism" and plurality needed when addressing the problem of overpopulation. 3 main starting point are defined for the determination of a population ethic: 1) ethics defined in terms of "nature," 2) in terms of the "human person," and 3) in terms of social "dialectic" involvement. The first point stresses the natural order of things as prescribed by God and impugns any birth control method; however, so-called natural birth control methods are allowed. The second point suggests that the human person is ethically center stage, a modernized position taken by the Church in tune with social realities and man's inherent intelligence. The primacy of live and responsibility is stressed as opposed to mere biological processes. Following this view, use of contraceptive, and even sterilization is allowed; however, abortion is excluded, since it means the elimination of a human life. The problem of overpopulation should be solved within the individual or micro-social context. The third point holds that it would be extremely myopic to reduce the position of the Church to advocating exclusively natural birth control methods while excluding social involvement. A "cosmic" view of faith would end putting material well-being before individual personal lives, would alert against egoism disguised as quality of life enhancement, and ultimately result in socially responsible fertility. In conclusion, the Church acknowledges that its contribution to the question of population ethics occurs in a pluralistic society that does not

  14. Anaerobic fungal populations

    International Nuclear Information System (INIS)

    Brookman, J.L.; Nicholson, M.J.

    2005-01-01

    The development of molecular techniques has greatly broadened our view of microbial diversity and enabled a more complete detection and description of microbial communities. The application of these techniques provides a simple means of following community changes, for example, Ishii et al. described transient and more stable inhabitants in another dynamic microbial system, compost. Our present knowledge of anaerobic gut fungal population diversity within the gastrointestinal tract is based upon isolation, cultivation and observations in vivo. It is likely that there are many species yet to be described, some of which may be non-culturable. We have observed a distinct difference in the ease of cultivation between the different genera, for example, Caecomyes isolates are especially difficult to isolate and maintain in vitro, a feature that is likely to result in the under representation of this genera in culture-based enumerations. The anaerobic gut fungi are the only known obligately anaerobic fungi. For the majority of their life cycles, they are found tightly associated with solid digesta in the rumen and/or hindgut. They produce potent fibrolytic enzymes and grow invasively on and into the plant material they are digesting making them important contributors to fibre digestion. This close association with intestinal digesta has made it difficult to accurately determine the amount of fungal biomass present in the rumen, with Orpin suggesting 8% contribution to the total microbial biomass, whereas Rezaeian et al. more recently gave a value of approximately 20%. It is clear that the rumen microbial complement is affected by dietary changes, and that the fungi are more important in digestion in the rumens of animals fed with high-fibre diets. It seems likely that the gut fungi play an important role within the rumen as primary colonizers of plant fibre, and so we are particularly interested in being able to measure the appearance and diversity of fungi on the plant

  15. Population Health and Occupational Therapy.

    Science.gov (United States)

    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.

  16. Lithuanian Population Aging Factors Analysis

    Directory of Open Access Journals (Sweden)

    Agnė Garlauskaitė

    2015-05-01

    Full Text Available The aim of this article is to identify the factors that determine aging of Lithuania’s population and to assess the influence of these factors. The article shows Lithuanian population aging factors analysis, which consists of two main parts: the first describes the aging of the population and its characteristics in theoretical terms. Second part is dedicated to the assessment of trends that influence the aging population and demographic factors and also to analyse the determinants of the aging of the population of Lithuania. After analysis it is concluded in the article that the decline in the birth rate and increase in the number of emigrants compared to immigrants have the greatest impact on aging of the population, so in order to show the aging of the population, a lot of attention should be paid to management of these demographic processes.

  17. Climate and waterfowl populations

    International Nuclear Information System (INIS)

    Diamond, A.W.; Brace, R.K.

    1991-01-01

    Climate affects waterfowl populations through a variety of pathways, categorized as direct impacts (physiological effects on the bird itself), and indirect, acting through the bird's habitats and changes in land use practices. Graphs are presented of wetland use by Prairie ducks, duck use by pothole size and class, duck use by wetland type, wetland use by grebes, numbers of nongame birds, wetland use by shorebirds and wetland use by blackbirds. Wetlands are classified according to the following scheme: ephemeral and temporary, which are shallow and are first to thaw in the spring; seasonal, which become available later in the year and last longer; semipermanent wetlands, which hold water well into late summer; permanent wetlands, which are relatively less productive than other types, and which are mainly used as staging habitat for fall migration; and alkali wetlands, which are relatively little used. The types of wetland available to waterfowl and other migratory birds are as important as numbers and total area. In general, smaller wetlands are more important than larger, more permanent water bodies. Small, impermanent wetlands are more vulnerable to climatic warming and drying, and species such as waterfowl and migratory birds in general are at great risk from further drying of the hydrological regime of the Prairies and Great Plains. 12 refs., 9 figs

  18. population in Slovakia

    Directory of Open Access Journals (Sweden)

    Dravecký Miroslav

    2015-06-01

    Full Text Available V rokoch 2011 – 2014 sa realizoval monitoring hniezdnej populácie orla krikľavého (Aquila pomarina v ôsmich chránených vtáčích územiach na Slovensku. U 149 hniezdnych párov z celkových 272 úspešných hniezdení počas 4 hniezdnych sezón vyletelo 277 mláďat. Priemerná reprodukčná úspešnosť predstavovala 0,51 juv./prítomný pár, 0,69 juv./hniezdiaci pár a 1,37 juv./100 km2. V uvedenom období bolo okolo hniezd orlov krikľavých ustanovených celkom 151 ochranných zón, ktoré zabezpečili ochranu 119 hniezdnych teritórií, čo predstavuje cca 17 % hniezdnej populácie orla krikľavého na Slovensku. Testovaním účinnosti ochranných zón sa zistilo, že v hniezdach s vyhlásenou ochrannou zónou je vyššia pravdepodobnosť úspešného odchovania mláďat v porovnaní s hniezdami bez takejto zóny. Pravdepodobnosť, že hniezdenie bude úspešné v hniezdach hniezdiacich párov bez ochrannej zóny bola 48.1% (95% confidence intervals (CIs: 37.4–59.0%, v hniezdach s ochrannou zónou 64.8% (95% CIs: 59.8–69.6%. Medzi 5 najčastejšie využívaných hniezdnych stromov na hniezdenie A. pomarina na Slovensku patrí Picea abies 61× (28,4%, Pinus sylvestris 45× (20,9%, Quercus sp. 36× (16,7%, Fagus sylvatica 25× (11,6% a Abies alba 18× (8,4%. Medzi zriedkavejšie druhy hniezdnych stromov patrí Larix decidua 12× (5,6% a Alnus glutinosa 3× (1,4%, ďalších 11 druhov hniezdnych stromov nedosiahli 1 %. Najvyšší počet hniezdnych stromov (n = 215, tj. 34 hniezd (15,8% sa nachádzal v intervale nadmorskej výšky 401 – 450 m a 29 hniezd (13,5% v intervale 351 – 400 m n. m. Ostatné výškové pásma boli pod hranicou 10%. 54% zistených hniezd (116 hniezd sa nachádza vo výškovom pásme 301 – 600 m n. m., 71 hniezd (33% v pásme 600 – 900 m n. m. Najnižšie situované hniezdo bolo v nadmorskej výške 150 m a najvyššie 950 m, priemer bol 595,01 m. Najvyšší počet hniezd (n = 209 bol na strome

  19. Browsing Isolated Population Data

    Directory of Open Access Journals (Sweden)

    Manias Teresa

    2005-12-01

    Full Text Available Abstract Background In our studies of genetically isolated populations in a remote mountain area in the center of Sardinia (Italy, we found that 80–85% of the inhabitants of each village belong to a single huge pedigree with families strictly connected to each other through hundreds of loops. Moreover, intermarriages between villages join pedigrees of different villages through links that make family trees even more complicated. Unfortunately, none of the commonly used pedigree drawing tools are able to draw the complete pedigree, whereas it is commonly accepted that the visual representation of families is very important as it helps researchers in identifying clusters of inherited traits and genotypes. We had a representation issue that compels researchers to work with subsets extracted from the overall genealogy, causing a serious loss of information on familiar relationships. To visually explore such complex pedigrees, we developed PedNavigator, a browser for genealogical databases properly suited for genetic studies. Results The PedNavigator is useful for genealogical research due to its capacity to represent family relations between persons and to make a visual verification of the links during family history reconstruction. As for genetic studies, it is helpful to follow propagation of a specific set of genetic markers (haplotype, or to select people for linkage analysis, showing relations between various branch of a family tree of affected subjects. Availability PedNavigator is an application integrated into a Framework designed to handle data for human genetic studies based on the Oracle platform. To allow the use of PedNavigator also to people not owning the same required informatics infrastructure or systems, we developed PedNavigator Lite with mainly the same features of the integrated one, based on MySQL database server. This version is free for academic users, and it is available for download from our site http://www.shardna.com.

  20. On the cells of origin of radiogenic thyroid cancer

    International Nuclear Information System (INIS)

    Clifton, K.H.; Domann, F.E.; Groch, K.M.

    1991-01-01

    A major effort has been devoted to studies of the origins of radiogenic and hormonally-induced cancer at the cellular level in vivo. The studies has provided evidence that the functional thyroid follicules (follicular units, FU) which are formed in grafts of monodispersed rat thyroid cells, and hence the thyroid tumors which later develop in such grafts, are clonal in origin. Transplantation assays indicate that the clonogens comprise 1% of the cells in monodispersed suspensions of normal thyroid tissue. Carcinogenesis studies show that neoplastic initiation of thyroid clonogens by radiation is a commo event. Promotion-progression to cancer from radiation initiated clonogens has, however, been shown to be inversely related to the total grafted thyroid cell number. It is thus important to further define the physiology and population kinetics of the thyroid clonogens under different hormonal conditions both in situ and following transplantion. This report briefly summarizes recent data on (a) local cell-cell and remote hormonal feedback interactions during neoplastic promotion of initiated cells among the progeny of grafted clonogens in multicellular FU; (b) clonogenic cell population kinetics in situ during goitrogenesis and goiter involution; and (c) the reestablishment of the thyroid-hypothalamus-pituitary hormonal feedback system in thyroid cell-grafted thyroidectomized rats and its dependence on the formation of FU by the grafted clonogens. These results support the conclusion that the thyroid gland contains a small sub-population of clonogenic epithelial cells which posess many stem cell-like characteristics. (N.K.)

  1. Murine bone marrow Lin⁻Sca⁻1⁺CD45⁻ very small embryonic-like (VSEL cells are heterogeneous population lacking Oct-4A expression.

    Directory of Open Access Journals (Sweden)

    Krzysztof Szade

    heterogeneous population, which do not express the pluripotency marker Oct-4A. Despite expression of some hematopoietic markers by a Lin(-Sca-1(+CD45(-c-Kit(+KDR(- subset of VSELs, they do not display hematopoietic potential in a clonogenic assay and are enriched in early apoptotic cells.

  2. Population adiposity and climate change.

    Science.gov (United States)

    Edwards, Phil; Roberts, Ian

    2009-08-01

    The increasing global prevalence of overweight and obesity has serious implications for the environment, as well as for health. We estimate the impact on greenhouse gas emissions of increases in the population distribution of body mass index (BMI). We estimated the food energy required to maintain basal metabolic rate in two hypothetical adult populations using the Schofield equations for males and females. Additional greenhouse gas emissions due to higher fuel energy use for transporting a heavier population were estimated. Compared with a normal population distribution of BMI, a population with 40% obese requires 19% more food energy for its total energy expenditure. Greenhouse gas emissions from food production and car travel due to increases in adiposity in a population of 1 billion are estimated to be between 0.4 Giga tonnes (GT) and 1.0 GT of carbon dioxide equivalents per year. The maintenance of a healthy BMI has important environmental benefits in terms of lower greenhouse gas emissions.

  3. Singapore’s Declining Population

    Science.gov (United States)

    2010-01-01

    ethnic groups work . In addition, they get married later in life and had fewer children. What does a declining population mean for Singapore...other countries. BACKGROUND Since gaining independence, Singapore’s population has grown along with its economy . As Singapore’s gross domestic...in the country mean fewer consumers. Fewer people in the country also means there are less people to support the elderly. As the population ages

  4. Evolutionary dynamics of diploid populations

    Science.gov (United States)

    Desimone, Ralph; Newman, Timothy

    2003-10-01

    There has been much recent interest in constructing computer models of evolutionary dynamics. Typically these models focus on asexual population dynamics, which are appropriate for haploid organsims such as bacteria. Using a recently developed ``genome template'' model, we extend the algorithm to a sexual population of diploid organisms. We will present some early results showing the temporal evolution of mean fitness and genetic variation, and compare this to typical results from haploid populations.

  5. Determinants of human population growth.

    Science.gov (United States)

    Lutz, Wolfgang; Qiang, Ren

    2002-09-29

    The 20th century has seen unprecedented growth of the human population on this planet. While at the beginning of the century the Earth had an estimated 1.6 billion inhabitants, this number grew to 6.1 billion by the end of the century, and further significant growth is a near certainty. This paper tries to summarize what factors lie behind this extraordinary expansion of the human population and what population growth we can expect for the future. It discusses the concept of demographic transition and the preconditions for a lasting secular fertility decline. Recent fertility declines in all parts of the world now make it likely that human population growth will come to an end over the course of this century, but in parts of the developing world significant population growth is still to be expected over the coming decades. The slowing of population growth through declining birth rates, together with still increasing life expectancy, will result in a strong ageing of population age structure. Finally, this paper presents a global level systematic analysis of the relationship between population density on the one hand, and growth and fertility rates on the other. This analysis indicates that in addition to the well-studied social and economic determinants, population density also presents a significant factor for the levels and trends of human birth rates.

  6. Population genetic analysis of cat populations from Mexico ...

    Indian Academy of Sciences (India)

    Unknown

    In this paper we identify new genetic profiles of eight Latin American cat populations. In addition, we combine data from the present study and previously published data on 70 other American and European populations to discuss (1) the points of introduction of mutant alleles for cat coat phenotypes from Europe into Latin ...

  7. Population dynamics and population control of Galium aparine L.

    NARCIS (Netherlands)

    Weide, van der R.Y.

    1993-01-01

    The population biology of Galium aparine L. needs to be better understood, in order to be able to rationalize decisions about the short- and long-term control of this weed species for different cropping practices.

    A population dynamics model was developed to

  8. Population genetic analysis of cat populations from Mexico ...

    Indian Academy of Sciences (India)

    Unknown

    Bolivia, and the Dominican Republic: identification of different gene pools in Latin America. J. Genet. 84, 147–171]. Introduction. The genetic ... populations has led to the identification of genetic rela- tionships among populations and ...... Evolution 44, 689–697. Rao C. R. 1951. Advanced statistical methods in biometric re-.

  9. Part II. Population

    International Nuclear Information System (INIS)

    2004-01-01

    This monograph deals with assessment of radiological health effects of the Chernobyl accident for emergency workers (part 1) and the population of the contaminated areas in Russia (part 2). The Chernobyl emergency workers and people living in the contaminated areas of Russia received much lower doses than the population of Hiroshima and Nagasaki and it was unclear whether risks of radiation-induced cancers derived with the Japanese data could be extrapolated to the low dose range However, it was predicted as early as in 1990 that the thyroid cancer incidence might be increasing due to incorporated 131 irradiation. What conclusions can be drawn from regarding cancer incidence among emergency workers and residents of the contaminated areas in Russia and the role of the radiation factor on the basis of the registry data? Leukemia incidence. Leukemia incidence is known to be one of principal indications of radiation effects. The radiation risk for leukemias is 3-4 times higher that for solid cancers and its latent period is estimated to be 2-3 years after exposure. Results of the radiation epidemiological studies discussed in this book show that in the worst contaminated Bryansk region the leukemia incidence rate is not higher than in the country in general. Even though some evidence exists for the dose response relationship, the radiation risks appear to be not statistically significant. Since risks of leukemia are known to be higher for those who were children at exposure, long-term epidemiological studies need to be continued. The study of leukemias among emergency workers strongly suggest the existence of dose response relationship. In those who received external doses more than 0.15 Gy the leukemia incidence rate is two time higher and these emergency workers should be referred to as a group of increased radiation risk. Solid cancers. The obtained results provide no evidence to a radiation-induced increase in solid cancers among residents of the contaminated areas

  10. Stochastic delocalization of finite populations

    International Nuclear Information System (INIS)

    Geyrhofer, Lukas; Hallatschek, Oskar

    2013-01-01

    The localization of populations of replicating bacteria, viruses or autocatalytic chemicals arises in various contexts, such as ecology, evolution, medicine or chemistry. Several deterministic mathematical models have been used to characterize the conditions under which localized states can form, and how they break down due to convective driving forces. It has been repeatedly found that populations remain localized unless the bias exceeds a critical threshold value, and that close to the transition the population is characterized by a diverging length scale. These results, however, have been obtained upon ignoring number fluctuations (‘genetic drift’), which are inevitable given the discreteness of the replicating entities. Here, we study the localization/delocalization of a finite population in the presence of genetic drift. The population is modeled by a linear chain of subpopulations, or demes, which exchange migrants at a constant rate. Individuals in one particular deme, called ‘oasis’, receive a growth rate benefit, and the total population is regulated to have constant size N. In this ecological setting, we find that any finite population delocalizes on sufficiently long time scales. Depending on parameters, however, populations may remain localized for a very long time. The typical waiting time to delocalization increases exponentially with both population size and distance to the critical wind speed of the deterministic approximation. We augment these simulation results by a mathematical analysis that treats the reproduction and migration of individuals as branching random walks subject to global constraints. For a particular constraint, different from a fixed population size constraint, this model yields a solvable first moment equation. We find that this solvable model approximates very well the fixed population size model for large populations, but starts to deviate as population sizes are small. Nevertheless, the qualitative behavior of the

  11. [Population science serves human happiness].

    Science.gov (United States)

    Qian, X

    1983-03-29

    4 areas are covered in this speech delivered on January 10, 1983. 1) Looking back on China's post-Liberation population problems: as early as the 1950s, the Party and scholars such as Ma Yinchu recognized the need to control population growth. For instance, a 1952 directive instructed the Public Health Bureau to encourage the use of condoms and diaphrams. When Ma Yinchu's studies showing alarming population increases were made known to Mao Zedong and published in the People's Daily in 1957, the "new population theory" was formed, which advocated population control. But before this idea gained currency, Ma suffered criticism in 1958 and population studies was virtually halted. Between 1958-61, as China entered difficult times, the birthrate declined. By 1962 the rate increased, leading the Central Committee of the Chinese Communist Party to issue a directive to control population. Again in 1971 the Central Government set population goals and incorporated population policies into national economic planning. When the wrongs of the Cultural Revolution were redressed, Ma Yinchu regained favor and demography entered a new era. 2) The responsibility of demographic studies: one of the most important tasks of demography is to solve the problem of confining the birthrate to 16-17/1000 annually, so that by 2000 the total population would be 1,200,000,000. This can only be done by advocating 1 child per couple, closely con trolling a 2nd birth and discouraging all 3rd births. 3) The contents of demographic studies: both immediate and future problems must be addressed. Areas of study can include sex ratio, marriage, family, population and land distribution, fertility, or an aging society. 4) Science research must embody a scientific attitude: it is best to follow the example set by Ma Yinchu, whose work was based on actual investigations in the field. Any development and production of scientific theory must stem from practical experience.

  12. Radiogenic neoplasia in thyroid and mammary clonogens. Final progress report, 1 January 1987--31 December 1997

    International Nuclear Information System (INIS)

    Clifton, K.H.

    1998-01-01

    The induction of cancer by ionizing radiation is a matter of great practical importance to the nuclear industry, to national defense, to radiological medicine and to the general public. It is increasingly apparent that carcinogenesis is a leading dose-limiting effect of radiation exposure. The thyroid and mammary glands are among the most sensitive human tissues to radiogenic initiation of cancer, and there is a profoundly higher risk of neoplastic initiation in these glands among individuals irradiated before or during puberty than among those exposed in later life. The authors developed unique quantitative experimental models to investigate and characterize the cells of origin of thyroid and mammary cancers and the effects of radiation on them (C185). To study these progenitor cells in vivo it is necessary to have a system by which their concentrations, total numbers and responses to radiation and other factors can be measured. It is a truism that not all cells in a tissue are equally sensitive to neoplastic initiation. They reasoned that the progenitor cells are most likely members of that subpopulation that is necessary to maintenance of normal tissue cell numbers and to repair and replacement after tissue damage. They further reasoned that such cells would likely be responsive to specific mitogenic stimulation by hormones. On the basis of these considerations, they developed quantitative rat thyroid and mammary epithelial cell transplantation systems

  13. Automatic cell cloning assay for determining the clonogenic capacity of cancer and cancer stem-like cells

    Czech Academy of Sciences Publication Activity Database

    Fedr, Radek; Pernicová, Zuzana; Slabáková, Eva; Straková, Nicol; Bouchal, J.; Grepl, M.; Kozubík, Alois; Souček, Karel

    83A, č. 5 (2013), s. 472-482 ISSN 1552-4922 R&D Projects: GA ČR(CZ) GPP301/12/P407; GA MZd(CZ) NT13573 Grant - others:GA AV(CZ) M200041203; GA MŠk(CZ) ED1.100/02/0123 Institutional support: RVO:68081707 Keywords : PROSTATE-CANCER * BASAL-CELLS * ORIGIN Subject RIV: BO - Biophysics Impact factor: 3.066, year: 2013

  14. Maintenance of Clonogenic KIT+ Human Colon Tumor Cells Requires Secretion of Stem Cell Factor by Differentiated Tumor Cells

    NARCIS (Netherlands)

    Fatrai, Szabolcs; Van Schelven, Susanne J.; Ubink, Inge; Govaert, Klaas M.; Raats, Danielle; Koster, Jan; Verheem, Andre; Borel Rinkes, Inne H M; Kranenburg, Onno

    2015-01-01

    Background & Aims Colon tumors contain a fraction of undifferentiated stem cell-like cancer cells with high tumorigenic potential. Little is known about the signals that maintain these stem-like cells. We investigated whether differentiated tumor cells provide support. Methods We established

  15. Estimated population near uranium tailings

    International Nuclear Information System (INIS)

    Bloomster, C.H.; Brown, D.R.; Bruno, G.A.; Craig, S.N.; Dirks, J.A.; Griffin, E.A.; Reis, J.W.; Young, J.K.

    1984-01-01

    Population studies, which took place during the months of April, May, and June 1983, were performed for 27 active and 25 inactive mill sites. For each mill site, a table showing population by radius (1/2, 1, 2, 3, 4, and 5 km) in 16 compass directions was generated. 22 references, 6 tables

  16. Do people fear population decline?

    NARCIS (Netherlands)

    van Dalen, H.P.; Henkens, C.J.I.M.

    2011-01-01

    This week the world population is projected to reach seven billion. Yet in some countries the prospect of a decline in population is worrying policymakers far more. This columns asks what the people think, focusing on a survey from the Netherlands. It turns out that most people are in favour of

  17. U.S. Population Growth.

    Science.gov (United States)

    Dillner, Harry

    This autoinstructional lesson deals with the study of man and his environment. No previous experience or learning in this field is required. Emphasis is placed on analysis of population growth and the impact population growth and trends have on natural resource depletion. The behavioral objectives (five) are listed. The study guide for the…

  18. Food for the ageing population

    NARCIS (Netherlands)

    Raats, M.M.; Groot, de C.P.G.M.; Staveren, van W.A.

    2008-01-01

    The world’s ageing population is increasing and food professionals will have to address the needs of older generations more closely in the future. This unique volume reviews the characteristics of the ageing population as food consumers, the role of nutrition in healthy ageing and the design of food

  19. Mega-Planning in Population

    Science.gov (United States)

    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…

  20. Population Growth: Crisis and Challenge.

    Science.gov (United States)

    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…

  1. Paths for Future Population Aging.

    Science.gov (United States)

    Grigsby, Jill S.

    Population aging refers to an entire age structure becoming older. The age structure of a population is the result of three basic processes: fertility, mortality, and migration. Age structures reflect both past effects and current patterns of these processes. At the town, city, or regional level, migration becomes an important factor in raising…

  2. Population. Environmental Ecological Education Project.

    Science.gov (United States)

    Parkway School District, Chesterfield, MO.

    This unit on population, designed for senior high school students, is divided into six packets with the following major topics: general introduction to the effects of a growing population, urbanization, family structures, family planning, consumption, environmental decay, and controlling the environment. Each packet contains a list of the topical…

  3. Assessment of ASEAN population programme.

    Science.gov (United States)

    1982-01-01

    The objectives of the 5th meeting of the ASEAN Heads of Population Program, held at Chiang Mai during November 1981, were the following: to discuss and consider the midterm reviews of some of the Phase 1 projects; to discuss and consider the ASEAN population experts' views on the progress made in the rest of the phase 1 projects; to discuss and consider the progress made in the implementation of the phase 2 projects; to discuss and consider the ASEAN population experts' recommendations on the ASEAN population program in the 1980s based on the report of the programming exercise submitted by the consultant in the expert group meeting; and to discuss administrative and other problems faced by the program implementors in the operationalization of the ongoing ASEAN population projects and provide appropriate directions to solve such problems. As a result of the programming exercise, the meeting established the directions for the future ASEAN population program and strongly recommended the continuation, intensification, and expansion of the ASEAN population program. A total of 12 projects comprise the ASEAN population program: 5 projects under phase 1 and 7 under phase 2. Under phase 1, 1 project has been completed, and the 1st parts of 2 other projects are in the process of implementation. Phase 2 projects, which started in September/October 1980, are all in the process of implementation. The following phase 1 projects are summarized: integration of population and rural development policies and programs; modular training for trainers of population and development agencies in ASEAN countries; multi-media support for population programs in the context of rural development in ASEAN countries; and migration in relation to rural development. The following phase 2 projects are also summarized: institutional development and exchange of personnel; women in development in ASEAN countries; and migration in relation to rural development. The following phase 2 projects are also

  4. Population information, education and communication.

    Science.gov (United States)

    1995-09-01

    Over the years UNFPA has used the information, education, and communication strategy to create awareness about population issues in more than 100 countries. The annual UNFPA publication The State of World Population has received worldwide media attention. Population issues are also aired through the annual World Population Day, which includes an international poster competition. Radio is used for spreading the message of population control but it could be employed more effectively given the 1.9 billion radio sets in the world. In Peru community-operated radio stations offer information on immunizations, reproductive health, and family planning. Some 20 countries have launched their own television programs in the form of mini-dramas to promote reproductive health and family planning. Mexico's family planning soap opera is highly popular in other Latin American countries. Multimedia campaigns are the most effective way of increasing public awareness about population and health-related issues. In Egypt the state-controlled television network is running a highly successful series of family planning mini-dramas. The country's contraceptive prevalence rate was nearly 50% in 1995 and rising. Similar successes have been reported in Mexico and Turkey. The growth of regional and international population information networks has been decisive in disseminating information. These include the UN Population Information Network (POPIN); the POPIN ASEAN for members of the Association of South-East Asian Nations (ASEAN); POPIN Africa; DOCPAL set up for Latin American countries; and PROLAP with the participation of 50 nongovernmental organizations. In the 1960s and 1970s population education also rapidly expanded in schools, and by the mid-1980s about 80 countries had population education in their schools. As of 1994 about 100 countries had such projects in schools. In addition, more attention is paid in schools to family planning, human sexuality, and gender issues. The major

  5. [Population problems and theories in old China].

    Science.gov (United States)

    Li, S

    1980-03-01

    Population theories in China before the revolution are reviewed. The author considers whether there was a population problem, whether a surplus population did exist, and to what extent population pressures existed.

  6. Human Population: Fundamentals of Growth and Change.

    Science.gov (United States)

    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";…

  7. Bangladesh. Population education programme reviewed.

    Science.gov (United States)

    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

  8. Modern population trends in Bangladesh.

    Science.gov (United States)

    Abul-basher, M M

    1985-01-01

    Population growth trends in Bangladesh in the 1871-1981 period were analyzed, with emphasis on fertility and mortality differentials, to provide a basis for population planning. Following proclamation of British Imperial Rule in 1857, mortality rates in Bangladesh began to decline as a result of preventive measures against natural disasters such as draught and famine, but the fertility rate remained unaltered. The demographic pattern was unstable over time, reflecting the impact of the influenza epidemic of 1918-19, war, migration, and economic development. Population growth accelerated greatly during the 1961-74 period, when industrialization emerged and job opportunities were created in the urban centers. Economic hardship, food shortages, and the introduction of family planning curbed urban growth drastically and total growth to some extent in 1974-81. On the average, growth has been higher in the Dhaka and Chittagong Divisions of Bangladesh than in the Khulna and Rajshahi Divisions. Differences in population growth among the regions are attributable largely to internal and external migration. The regression polynomial model best fits past population trends in Bangladesh and can reproduce the observed population by 99.60%. This polynomial is most suitable for graduation and prediction of population trends.

  9. Can human populations be stabilized?

    Science.gov (United States)

    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.

  10. NIDI scenario. Strong population decline in China

    OpenAIRE

    de Beer, J.A.A.

    2016-01-01

    United Nations projections assume that by the end of this century one third of the world population will live in India, China or Nigeria. While population growth in India will slow down and the population size of China will decline, population growth in Nigeria will accelerate. A new NIDI scenario projects less population growth in Nigeria and sharp population decline in China.

  11. Population and resources in Mauritius.

    Science.gov (United States)

    Royle, S A

    1995-05-01

    "The island of Mauritius was facing a crisis by the 1950s as the relationship between its population and resources became unbalanced....A two-pronged strategy was set in place to change the relationship between population and resources. Firstly, an aggressive family-planning policy was established, reducing population growth. Secondly, the economy was diversified with tourism, financial services and, especially, manufacturing in the Mauritius Export Processing Zone, creating extra finance and resources. The changes have not been cost-free but Mauritius ends the century, not as a classic case of overpopulation, but more [as] a model micro-state that has overcome many population and resource problems, largely through its own efforts." excerpt

  12. Population Issues. Resources in Technology.

    Science.gov (United States)

    Technology Teacher, 1991

    1991-01-01

    Presents information about the problems caused by increasing population. Discusses the environmental impact and the ways that technology can be used to solve problems of overpopulation. Includes possible student outcomes and a student quiz. (JOW)

  13. Wolf population genetics in Europe

    DEFF Research Database (Denmark)

    Hindrikson, Maris; Remm, Jaanus; Pilot, Malgorzata

    2017-01-01

    , resulting in a significant decrease in their numbers, genetic diversity and gene flow between populations. For more effective protection and management of wolf populations in Europe, robust scientific evidence is crucial. This review serves as an analytical summary of the main findings from wolf population...... genetic studies in Europe, covering major studies from the ‘pre-genomic era’ and the first insights of the ‘genomics era’. We analyse, summarize and discuss findings derived from analyses of three compartments of the mammalian genome with different inheritance modes: maternal (mitochondrial DNA), paternal...... (Y chromosome) and biparental [autosomal microsatellites and single nucleotide polymorphisms (SNPs)]. To describe large-scale trends and patterns of genetic variation in European wolf populations, we conducted a meta-analysis based on the results of previous microsatellite studies and also included...

  14. Evacuating populations with special needs

    Science.gov (United States)

    2009-04-01

    Evacuation operations are conducted under the authority of, and based on decisions by, local and state authorities. The purpose of this primer, Evacuating Populations with Special Needs, is to provide local and state emergency managers, government of...

  15. The Veteran Population Projection 2014

    Data.gov (United States)

    Department of Veterans Affairs — VetPop2014 is an actuarial projection model developed by the Office of the Actuary (OACT) for Veteran population projection from Fiscal Year FY2014 to FY2043. Using...

  16. Modeled population exposures to ozone

    Data.gov (United States)

    U.S. Environmental Protection Agency — Population exposures to ozone from APEX modeling for combinations of potential future air quality and demographic change scenarios. This dataset is not publicly...

  17. Correctional Facility Average Daily Population

    Data.gov (United States)

    Montgomery County of Maryland — This dataset contains Accumulated monthly with details from Pre-Trial Average daily caseload * Detention Services, Average daily population for MCCF, MCDC, PRRS and...

  18. Information processing by neuronal populations

    National Research Council Canada - National Science Library

    Hölscher, Christian; Munk, Matthias

    2009-01-01

    ... simultaneously recorded spike trains 120 Mark Laubach, Nandakumar S. Narayanan, and Eyal Y. Kimchi Part III Neuronal population information coding and plasticity in specific brain areas 149 7 F...

  19. India's population: second and growing.

    Science.gov (United States)

    Visaria, P; Visaria, L

    1981-10-01

    Attention in this discussion of the population of India is directed to the following: international comparisons, population pressures, trends in population growth (interstate variations), sex ratio and literacy, urban-rural distribution, migration (interstate migration, international migration), fertility and mortality levels, fertility trends (birth rate decline, interstate fertility differentials, rural-urban fertility decline, fertility differentials by education and religion, marriage and fertility), mortality trends (mortality differentials, health care services), population pressures on socioeconomic development (per capita income and poverty, unemployment and employment, increasing foodgrain production, school enrollment shortfalls), the family planning program, implementing population policy statements, what actions would be effective, and goals and prospects for the future. India's population, a total of 684 million persons as of March 1, 1981, is 2nd only to the population of China. The 1981 population was up by 136 million persons, or 24.75%, over the 548 million enumerated in the 1971 census. For 1978, India's birth and death rates were estimated at 33.3 and 14.2/1000 population, down from about 41.1 and 18.9 during the mid-1960s. India's current 5-year plan has set a goal of a birth rate of 30/1000 population by 1985 and "replacement-level" fertility--about 2.3 births per woman--by 1996. The acceleration in India's population growth has come mainly in the past 3 decades and is due primarily to a decline in mortality that has markedly outstripped the fertility decline. The Janata Party which assumed government leadership in March 1977 did not dismantle the family planning program, but emphasis was shifted to promote family planning "without any compulsion, coercion or pressures of any sort." The policy statement stressed that efforts were to be directed towards those currently underserved, mainly in rural areas. Hard targets were rejected. Over the 1978

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

    Directory of Open Access Journals (Sweden)

    Huikuan Chu

    2014-01-01

    Full Text Available 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.

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

    Science.gov (United States)

    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

  2. Canada's population: growth and dualism.

    Science.gov (United States)

    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.

  3. Population and Employment in China

    OpenAIRE

    Keyfitz, N.

    1982-01-01

    China's effectiveness in population control can be credited to the direct line of command through party and administrative cadres that extends from the leadership in Beijing down to the production team in a distant rural commune. The reason that the administrative machine has devoted so much attention to population control is twofold: the perceived limits of the natural environment, as indicated by slowness of growth of food supplies, and the difficulty of arranging productive employment for ...

  4. Population growth and infant mortality

    OpenAIRE

    Fabella, Christina

    2008-01-01

    The relationship between population growth and economic outcomes is an issue of great policy significance. In the era of the Millennium Development Goals, poverty and its correlates have become the compelling issues. Economic growth may not automatically translate into reductions in poverty and its correlates (may not trickle down) if income distribution is at the same time worsening. We therefore investigate the direct effect of population growth on infant mortality for various income catego...

  5. Regional Population Projections for China

    OpenAIRE

    Toth, F.L.; Cao, G.-Y.; Hizsnyik, E.

    2003-01-01

    Considering the size and the regional diversity of China, a prudent analysis of many economic and policy issues needs to consider the regional differences in climate, soil, water, and other natural resource endowments, population density, and social and economic development. Future-oriented multi-regional assessments require regionally detailed scenarios. A key component of such scenarios is the evolution of the population in different regions. For studies of land-use change and agriculture, ...

  6. Indonesia: population central to development.

    Science.gov (United States)

    1994-05-01

    The Indonesian representative to the 50th session of the Economic and Social Commission for Asia and the Pacific (ESCAP) reiterated the issue of population as being central to sustainable development. Indonesia recognizes that quality of life, which can be improved with education, health, skills, productivity, self reliance, and resiliency, has an impact on the process of development. Without quality improvements, large numbers of people become a burden. Population programs must aim to reduce population growth rates simultaneously with enhancing the quality of life. Women's improvement in education, health, and employment opportunities must be accomplished because of women's important role in national development. The goals of sustainable development are to maintain a balance between human needs and desires of the population and available resources and the environment. Sustainable development is necessary for present and future generations. The Fourth Asian and Pacific Population Conference was held in Bali in August 1992, at which time the Bali Declaration was affirmed. At the January 1994 meeting of officials regarding the implementation of the Bali Declaration held in Bangkok, Thailand, the Indonesian representative stressed the importance of the vigorous involvement of the ESCAP secretariat in planning and implementing population programs in the region. Recommendations included in the Bali Declaration are related to the issues being addressed at the International Conference on Population and Development to be held in Cairo in September 1994. The secretariat was also asked by the Indonesian representative to disseminate information on the implementation of the Bali Declaration through regular publications and other appropriate venues. Comprehensive data collection and information systems were needed on the links between population, development, and resources.

  7. Population, education and sustainable development.

    Science.gov (United States)

    Johnston, T

    1992-12-01

    The author examines the interrelationships between population growth and education, with a focus on Sub-Saharan Africa. "The gross body of evidence suggests that for all developing regions (and for sub-saharan Africa specifically) rapid population growth deleteriously impacts upon the quantity and quality of schooling. In a reciprocal fashion, the variables which underpin rapid and differential growth (fertility, mortality and migration) are themselves influenced by quantum of formal schooling and by other educational processes." excerpt

  8. Environmental pollution and population policies.

    Science.gov (United States)

    1980-04-01

    There is a growing recognition in Malaysia of the interrelationship between population growth, population policies, development policies, and environmental pollution. In Malaysia, with a current population of 13,250,000 and an annual growth rate of 2.4%, economic development is leading to large scale deforestation which in turn is altering climatic conditions, reducing water supplies, and increasing erosion. According to estimates 750,000 acres of jungle were cleared in the last 10 years. Industrial wastes and domestic sewage discharged into rivers and lakes is endangering marine life and padilands. This is a serious problem, since 70% of the Malaysian population derives the bulk of their protein intake from marine life. Noise and carbon monoxide pollution in urban areas is increasing due to the 15% annual increase in the number of vehicles in the country. These dangers need to be taken into account as continuing efforts are made to increase industrialization in order to provide jobs for the 350,000 unemployed and underemployed youth in the country. Fortunately, government officials in Malaysia are giving consideration to energy, water and oil conservation in formulating development plans and are becoming increasingly aware that population growth and population policies have a direct impact on development planning and environmental pollution.

  9. Global fertility and population trends.

    Science.gov (United States)

    Bongaarts, John

    2015-01-01

    Over the past several decades, the world and most countries have undergone unprecedented demographic change. The most obvious example of this change is the rise in human numbers, and there are also important trends in fertility, family structure, mortality, migration, urbanization, and population aging. This paper summarizes past trends and projections in fertility and population. After reaching 2.5 billion in 1950, the world population grew rapidly to 7.2 billion in 2013 and the projections expect this total to be 10.9 billion by 2100. World regions differ widely in their demographic trends, with rapid population growth and high fertility continuing in the poorest countries, particularly in sub-Saharan Africa, while population decline, population aging, and very low fertility are now a key concern in many developed countries. These trends have important implications for human welfare and are of interest to policy makers. The conclusion comments briefly on policy options to address these adverse trends. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  10. Evolutionary dynamics in structured populations

    Science.gov (United States)

    Nowak, Martin A.; Tarnita, Corina E.; Antal, Tibor

    2010-01-01

    Evolutionary dynamics shape the living world around us. At the centre of every evolutionary process is a population of reproducing individuals. The structure of that population affects evolutionary dynamics. The individuals can be molecules, cells, viruses, multicellular organisms or humans. Whenever the fitness of individuals depends on the relative abundance of phenotypes in the population, we are in the realm of evolutionary game theory. Evolutionary game theory is a general approach that can describe the competition of species in an ecosystem, the interaction between hosts and parasites, between viruses and cells, and also the spread of ideas and behaviours in the human population. In this perspective, we review the recent advances in evolutionary game dynamics with a particular emphasis on stochastic approaches in finite sized and structured populations. We give simple, fundamental laws that determine how natural selection chooses between competing strategies. We study the well-mixed population, evolutionary graph theory, games in phenotype space and evolutionary set theory. We apply these results to the evolution of cooperation. The mechanism that leads to the evolution of cooperation in these settings could be called ‘spatial selection’: cooperators prevail against defectors by clustering in physical or other spaces. PMID:20008382

  11. "Population policy in developed countries.".

    Science.gov (United States)

    Baldwin, G B

    1973-12-01

    Bernard Berelson's book, "Population Policy in Developed Countries," provides a report on population policy in the developed world as of the early 1970s, covering countries with 20 million population or over, and 11 countries of special interest. There are chapters by national experts from 25 countries. A developed country is defined as industrialized, healthier, better educated, better off, more modernized, and distinguished by low fertility. This does not mean that population growth in these countries has yet fallen to zero or lower, but in 7 or 8 countries, population is expected to stabilize in a decade or so unless recent fertility trends reverse themselves or are offset by immigration. The conclusions drawn from the 25 country reports are summarized, and highlights of the demographic situation and policies in 12 of the countries are presented, Berelson is cautious in predicting the future shape of population policy in the developed world. There have been too many policy changes in the past to be confident of the future. He feels, however, that more and more people are likely to accept the goal of replacement, up to replacement in some countries and down to replacement in others.

  12. The Soviet Union and population: theory, problems, and population policy.

    Science.gov (United States)

    Di Maio, A J

    1980-04-01

    Until the important public dialog on 3rd World population issues began in the Soviet Uuion in 1965, ideological limitations and bureaucratic interests prevented policy makers from recognizing the existence of a world of national "population problem." Since then, freer discussions of the Soviet Union's surprising decline in birthrate and labor shortages have led to serious policy questions. Conflicting policy goals, however, have resulted in only modest pronatalist policies. The Soviet population problem is a result of interregional disparities in population growth rates between the highly urbanized Soviet European populations with low birth rates and the least urbanized Central Asians with dramatically higher birth rates. As a result, these essentially Muslim people will provide the only major increases in labor resources and an increasing percentage of Soviet armed forces recruits. Policy planners are thus faced with difficult options. Current policies stressing technological transfers from the west and greater labor productivity, however, are unlikely to solve further labor shortages and regional imbalances. Ultimately, nonEuropana regions will be in an improved bargaining position for more favorable nationwide economic policies and for a greater role in policy planning.

  13. Population growth and its implications

    Directory of Open Access Journals (Sweden)

    Badii, M. H.

    2005-01-01

    Full Text Available Human populations have grown at an unprecedented rate over the past three centuries. By 2001, the world population stood at 6.2 billion people. If the current trend of 1.4 % per year persists, the population will double in 51years. Most of that growth will occur in the less developed countries of Asia, Africa, and Latin America. There is a serious concern that the number of humans in the world and our impact on the environment will overload the life support systems of the earth. The crude birth rate is the number of births in a year divided by the average population. A more accurate measure of growth is the general fertility rate, which takes into account the age structure and fecundity of the population. The crude birth rate minus the crude death rate gives the rate of natural increase. When this rate reaches a level at which people are just replacing themselves, zero population growth is achieved. In the more highly developed countries of the world, growth has slowed are even reversed in recent years so that without immigration from other areas, population would be declining. The change from high birth and death rates that accompanies in industrialization is called a demographic transition. Many developing nations have already begun this transition. Death rates have fallen, but birth rates remain high. Some demographers believe that as infant mortality drops and economic development progresses so that people in these countries can be sure of secure future, they will complete the transition to a stable population or a high standard living. While larger populations bring many problems, they also may be a valuable resource of energy, intelligence, and enterprise that will make it possible to overcome resource limitation problems. A social just view argues that a more equitable distribution of wealth might reduce both excess population growth and environmental degradation. We have many more options now for controlling fertility than were available

  14. Philippine population policy: quo vadis?

    Science.gov (United States)

    Carino, L V

    1994-06-01

    In the Philippines, debate engendered in 1994 by the introduction of a antiabortifacient bill written in such broad language that it would outlaw most contraceptives recalls earlier debates on population policy and shows that not much has changed on the surface: the US is still providing funds, the Catholic Church is still opposing program advocates, and the population is still growing. The history of family planning (FP) in the Philippines developed during five periods: 1) prior to 1969 FP was offered only by private organizations; 2) from 1969 to 1974, the government began to incorporate FP as a policy; 3) from 1974 to 1986, FP and population issues were considered part of total development; 4) from 1986-1992, FP was subsumed under maternal and child health; and 5) from 1992 to the present, policy was enacted to balance population concerns with resources and development. This newsletter considers the first two stages. The written code of one of the precolonization self-governing indigenous peoples linked the number of permitted wives to population size and limited (through infanticide) the number of children a poor couple could have. During the 1960s, the Ford Foundation created a Population Institute, a protestant group established a countrywide Planned Parenthood Movement, and a Catholic Family Planning Association was formed. The public sector became involved when the Health Department of Manila sponsored a training seminar on FP. During the second stage, President Marcos began increasingly to support a government policy facilitating FP. By 1970, FP was an announced policy of his government. The Population Commission was to suffer many administrative changes during the period, but the emphasis on fertility reduction remained within a basic framework of a policy which gave every couple the right to choose their method of FP. By the end of 1974, more than 20 organizations had become involved in FP and more than 2000 clinics provided services. (This survey is

  15. Focus on managing population growth.

    Science.gov (United States)

    Brown, S

    1995-01-01

    For the past 4 decades, the world's population growth has threatened to outstrip the planet's ability to sustain it. According to recent projections, an end to the growth of world population is finally in sight. Dr. Joseph van Arendonk, deputy executive director of the United Nations Population Fund, told an international press conference that population growth is likely to begin falling before the mid-21st century. Currently, some 87 million couples worldwide wish to use contraception but have no access to services. Van Arendonk argued that 4% of overseas aid set aside for population programs would satisfy this unmet need. He also predicted that the average family size in developing countries would stabilize at 2.1 children within the next 55 years if these needs were met. This would still mean a global population of 10 billion in the year 2050, rising to a plateau of 11.6 billion within the following century. In developing countries fertility rates fell from 6.1 to 3.3 children per woman between the mid-1960s and the mid-1980s, while use of contraception increased from 10% to 50%. However, contraceptive users in the developing world must increase from 446 million in 1994 to 603 million in 2005 to keep population growth within such projected limits. The costs of providing the contraception will increase from US $528 million to US $752 million. The contraceptive needs of 603 million users in 2005 will require: 196 million sterilizations, 436 million IUD insertions, 898 million injectables, 12.3 billion cycles of OCs, and 55 billion condoms. To this end, IPPF plans greater accessibility of services, a wider range of effective methods, and the involvement of the male partner.

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

    OpenAIRE

    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...

  17. Population growth and economic growth.

    Science.gov (United States)

    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

  18. MPS views on population growth.

    Science.gov (United States)

    1997-09-01

    This article features the different views of Parliament members concerning the need in the reduction of population growth for development sustenance. Population growth would lead to environmental degradation, malnutrition, diseases, and high incidence of poverty. Furthermore, social problems arise like teenage pregnancies, and abuse of young girls. Suggestions on curtailing this problem as suggested by some of the parliament members includes educating people on issues of migration, family planning and reproductive health. Other members suggested on family planning legislation, like in the case of China where population explosion exists. Further, members thought that advocacy for population control such as condom usage targeting to couples having large families should be catered. However, this was denounced by some members as a failure and should not be sanctioned at large family couples but rather to husband with several wives. Finally, a compromised view was directed on population management with poverty alleviation involving the provision of amenities such as water, electricity, good roads, potable water, and income generating activities.

  19. Political economy of population growth.

    Science.gov (United States)

    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.

  20. Population dynamics in variable environments

    CERN Document Server

    Tuljapurkar, Shripad

    1990-01-01

    Demography relates observable facts about individuals to the dynamics of populations. If the dynamics are linear and do not change over time, the classical theory of Lotka (1907) and Leslie (1945) is the central tool of demography. This book addresses the situation when the assumption of constancy is dropped. In many practical situations, a population will display unpredictable variation over time in its vital rates, which must then be described in statistical terms. Most of this book is concerned with the theory of populations which are subject to random temporal changes in their vital rates, although other kinds of variation (e. g. , cyclical) are also dealt with. The central questions are: how does temporal variation work its way into a population's future, and how does it affect our interpretation of a population's past. The results here are directed at demographers of humans and at popula­ tion biologists. The uneven mathematical level is dictated by the material, but the book should be accessible to re...

  1. Global earthquake fatalities and population

    Science.gov (United States)

    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.

  2. Popullution: A Position Paper on Population.

    Science.gov (United States)

    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…

  3. Analysis of Population Dynamics in World Economy

    OpenAIRE

    Martin, Gress

    2011-01-01

    Population dynamics is an important topic in current world economy. The size and growth of population have an impact on economic growth and development of individual countries and vice versa, economic development influences demographic variables in a country. The aim of the article is to analyze historical development of world population, population stock change and relations between population stock change and economic development.

  4. Future directions in population health.

    Science.gov (United States)

    Hancock, T

    1999-01-01

    The long-term health of the population will be influenced by a number of major forces in the next century. In this brief review, particular emphasis is placed on environmental and economic forces. Major global environmental changes include climate change and global warming, resource depletion, ecotoxicity and reduced biodiversity. We do not yet know the impact on longevity of lifetime exposure to a mix of persistent toxic chemicals in our environment, since it has only been widespread in the past 40-50 years. The health impacts of global warming are only just beginning to be understood and could be profound. But perhaps the most profound threat to population health is economic growth, to the extent that it undermines environmental and social sustainability. We need a new form of capitalism, one that simultaneously increases environmental, social, economic and human capital, if population health is to be maintained in the 21st century.

  5. Cancer patterns in Inuit populations

    DEFF Research Database (Denmark)

    Melbye, M.; Friborg, Jeppe Tang

    2008-01-01

    Inuit people inhabit the circumpolar region, with most living in Alaska, northwest Canada, and Greenland. Although malignant diseases were believed to be almost non-existent in Inuit populations during the beginning of the 20th century, the increasing life expectancy within these populations showed...... a distinct pattern, characterised by a high risk of Epstein-Barr virus-associated carcinomas of the nasopharynx and salivary glands, and a low risk of tumours common in white populations, including cancer of the prostate, testis, and haemopoietic system. Both genetic and environmental factors seem...... to be responsible for this pattern. During the second half of the 20th century, Inuit societies underwent major changes in lifestyle and living conditions, and the risk of lifestyle-associated tumours, especially cancers of the lung, colon, and breast, increased considerably after changes in smoking, diet...

  6. Keynes, population, and equity prices.

    Science.gov (United States)

    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

  7. Population fluctuation in phytophagous insects

    Energy Technology Data Exchange (ETDEWEB)

    Redfearn, A.; Pimm, S.L. (Oak Ridge National Laboratory, TN (United States))

    1994-06-01

    We examined how community interactions affect year-to-year population variability in three groups of phytophagous insects: British aphids and moths, and Canadian moths. We first examined how the number of host plant species on which a given phytophagous insect species feeds affects its population variability. Specialist insect species showed a weak tendency to be more variable than generalist species. We then examined how the number of species of parasitoids from which a given phytophagous insects species suffers affects its population variability. Species that are host to few parasitoid species showed a weak tendency to be more variable than species with many parsitoid species. These relationships also depend on other aspects of the life histories of the phytophagous insect species.

  8. Complicated grief in Aboriginal populations.

    Science.gov (United States)

    Spiwak, Rae; Sareen, Jitender; Elias, Brenda; Martens, Patricia; Munro, Garry; Bolton, James

    2012-06-01

    To date there have been no studies examining complicated grief (CG) in Aboriginal populations. Although this research gap exists, it can be hypothesized that Aboriginal populations may be at increased risk for CG, given a variety of factors, including increased rates of all-cause mortality and death by suicide. Aboriginal people also have a past history of multiple stressors resulting from the effects of colonization and forced assimilation, a significant example being residential school placement. This loss of culture and high rates of traumatic events may place Aboriginal individuals at increased risk for suicide, as well as CG resulting from traumatic loss and suicide bereavement. Studies are needed to examine CG in Aboriginal populations. These studies must include cooperation with Aboriginal communities to help identify risk factors for CG, understand the role of culture among these communities, and identify interventions to reduce poor health outcomes such as suicidal behavior.

  9. Rapid population increase in an introduced muskox population, West Greenland

    Directory of Open Access Journals (Sweden)

    Carsten Riis Olesen

    1993-10-01

    Full Text Available In 1962 and 1965, 27 (13 and 14 muskox yearlings were translocated from East Greenland (71°N to the Angujaartorfiup Nunaa range in West Greenland (67°N. Angujaartorfiup Nunaa is a 6600 km2 icefree, continental area where caribou are indigenous. The climate is strictly continental with a minimum of precipitation but with abundant vegetation. Aerial surveys in 1990 documented that the muskox population has increased to 2600 heads despite quota-based harvesting since 1988. The annual quota was 200, 300 and 400 for 1988, 1989 and 1990, respectively. Distribution of muskoxen shows a significant preference for low altitude habitats southeast of Kangerlussuaq Airport and around Arnangarnup Qoorua (Paradise valley. Annual population increment averages 30% and the calf crop is around 24% of the population. Yearling recruitment in the population reveals that calf mortality during winter is very limited. About half of the 1-year-old females are served and they eventually give birth to their first calf when they turn 2 years old. With half of the 2-year-old females reproducing, the calf/cow ration ranges between 0.9 and 1.0.

  10. Population and Health in Developing Countries: Population, Health ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2002-01-10

    Jan 10, 2002 ... For the one billion people living in the world's poorest countries, where the burden of disease is highest, those who are born or who die are still not counted. The health profile of these populations is akin to an iceberg: the bulk of reliable data remains hidden. This great information void is a major, ...

  11. Population pressures in Latin America.

    Science.gov (United States)

    Merrick, T W; Kent, M M; Van Der Tak, J; Von Cube, A

    1986-07-01

    In 1950 Latin America's population of 165 million was on a par with the 166 million of North America. 2 decades of growth at nearly 3% a year pushed the total to 405 million in 1985, vs. 264 million in North America. Despite substantial fertility declines since the 1960s, continued growth is ensured by the demographic momentum built into the region's large and youthful population bases. UN medium projections put the 2025 total at 779 million, compared to 345 million in North America. This Bulletin examines the main demographic changes in Latin America since World War II and their links to economic and social changes in the region as well as their implications for international and social relations. The post World War II population surge was accompanied by massive rural-ruban and international migration, rapid urbanization, large labor shifts out of agriculture into industry and services, increased education for both men and women, and higher labor force participation for females. The rural exodus was spurred by extreme land tenure inequalities and the urban bias of postwar industrialization. The labor-saving bias of this industrialization forced exploding city populations to turn to the informal sector for jobs. Population pressures on city services and housing as well as jobs have been further exacerbated by overconcentration in a few large cities and economic downturns of the 1980s. Recent fertility declines seem to be the result of both increased access to family planning and the economic and social pressures posed by the gap between young adults' aspirations and their ability to realize them. Population and economic pressures could induce faster fertility declines than now projected but in the short run are likely to mean more employment problems, continued rapid urban growth, and even larger international immigration flows within the hemisphere, particularly to the US.

  12. [Population growth and the environment].

    Science.gov (United States)

    Hogan, D J

    1991-01-01

    The impact of population growth on the enviornment has been extensively researched; it consists of the depletion of resources (agricultural land absorbed by urban expansion, loss of soils, desertification, loss of biodiversity, less availability of minerals, dwindling of petroleum reserves) and the degradation of natural resources (air and water pollution). For politicians, journalists, and environmentalists, population growth is identified as the principal villain, which is a unidirectional and negative opinion. Demography is supposed to examine the negative and positive effects of the environment-population relationship; however, it is postulated that there has not been much produced in the last 2 centuries in this area. Examination of the research literature does not indicate any view that transcends the Malthusian vision, although a few empirical studies exist (Hogan, 1989). Durham (1979) identified the replacement of subsistence agriculture by export-oriented agriculture as the key factor in overpopulation in El Salvador and Honduras that led to migrations and international conflicts. Tudela (1987) related a similar process in the Mexican state of Tabasco, where a period of malnutrition was accompanied by the expansion of export agriculture and nutritional improvements emanated only from recapturing subsistence agriculture. Fearnside (1986) researched the dynamics of the occupation and destruction of Amazonia. However, Kahn and Simon went further and denied the existence of real environmental problems: population is the ultimate resource, and the more minds, the more good ideas and solutions for any problem. However, in all these cases of pure or modified Malthusianism the relation of population/resources is reduced to a unidimensional relationship; and fertility, mortality, migration, marriage, and age structure receive little attention. A prime candidate for the attention of population specialists should be migration and patterns of settlement and their

  13. Growing population causes of unemployment.

    Science.gov (United States)

    1995-01-01

    At the March, 1995, International Meeting on Population and Social Development in Copenhagen, during the session on unemployment, underemployment, and population it was stated that the problem of employment was the extent to which a nation's labor supply was not matched by labor demand or job opportunities. Population was thus a supply factor, and the country's economic situation was a demand factor. The demographic variables that were considered important in the supply of labor were: a) the size and rate of growth of the population, which was a function of the birth rate, the death rate, and migration; and b) the age structure of the population, which was also a product of the rate of growth of the population and its distribution. An imbalance between the supply of labor and the demand for it gave rise to unemployment and underemployment. The vicious cycle generated by a high dependency burden associated with a young age-structure led to low savings and investments, which in turn led to low economic growth and a low standard of living. This produced high fertility rates, which in turn heightened the dependency burden perpetuating the cycle. This vicious cycle could be broken at only two points: at the high fertility stage, primarily by introducing family planning programs; and at the stage of low economic growth, by adopting policies to accelerate economic growth. To be successful, however, both actions had to be pursued simultaneously. Numerous participants emphasized the global nature of the issue of unemployment and underemployment; the effects of international competition and restrictive trade policies on employment opportunities. The growing disparity between North and South had created a social injustice between countries. Several participants called for more humane policies that favored democracy and promoted human development, and asked for assistance to help create an enabling environment for social and economic development.

  14. Population change and the environment.

    Science.gov (United States)

    1989-01-01

    The environmental and natural resource problems that afflict most countries of the Asian and Pacific region are caused by human activities, often arising from the needs of growing populations for land to cultivate subsistence crops. These include the farming of marginal land; insufficient fallow periods; the clearing of forest land for agriculture and the felling of trees for firewood and timber. Water pollution, air pollution, deforestation and desertification are related to human activities. One of the priorities for population and development planning in the region will be action-oriented research into the linkages, to guide national and regional development policies. Both population and environmental concerns must be integrated into social and economic development plans in order for development to be sustainable. To achieve these goals, rapid population growth must be slowed and eventually stabilized, while strategies on optimal population distribution should be formulated. Concomitantly, environmental conditions must be maintained or improved through reversing deforestation and erosion in major watersheds; checking the spread of deserts; introducing sustainable water management; reducing acidification and hazardous waste; developing and introducing environmentally safe industrial processes; eliminating hunger through sustainable agriculture; finding new and renewable sources of energy and increasing energy efficiency; and protecting animal and plant species and preventing further loss. To avoid the possible negative consequences, balanced development in an integrated fashion is called for. As far as environmental problems are concerned, there is a growing need for the planning mechanism to take demographic variables into account in a more integrated way than has been done in the past. For purposes of environmental and population planning, a longer-term approach should be taken in addition to the five-year plans.

  15. Burst Populations and Detector Sensitivity

    Science.gov (United States)

    Band, David L.

    2003-01-01

    The F(sub T) (peak bolometric photon flux) vs. E(sub p) (peak energy) plane is a powerful tool to compare the burst populations detected by different detectors. Detector sensitivity curves in this plane demonstrate which burst populations the detectors will detect. For example, future CZT-based detectors will show the largest increase in sensitivity for soft bursts, and will be particularly well- suited to study X-ray rich bursts and X-ray Flashes. Identical bursts at different redshifts describe a track in the F(sub T)-E(sub p) plane.

  16. Structure of African elephant populations

    DEFF Research Database (Denmark)

    Siegismund, H R; Arctander, P

    1996-01-01

    The structure of elephant populations from east and south Africa has been analyzed by Georgiadis et al. (1994) on the basis of restriction site variation of mitochondrial DNA. They used F statistics based on identity by descent in tests for subdivision and reached the conclusion that there was a ......The structure of elephant populations from east and south Africa has been analyzed by Georgiadis et al. (1994) on the basis of restriction site variation of mitochondrial DNA. They used F statistics based on identity by descent in tests for subdivision and reached the conclusion...

  17. ISLSCP II Global Population of the World

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: Global Population of the World (GPW) translates census population data to a latitude-longitude grid so that population data may be used in...

  18. ISLSCP II Global Population of the World

    Data.gov (United States)

    National Aeronautics and Space Administration — Global Population of the World (GPW) translates census population data to a latitude-longitude grid so that population data may be used in cross-disciplinary...

  19. The Why and How of Population Education

    Science.gov (United States)

    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)

  20. Global Population Density Grid Time Series Estimates

    Data.gov (United States)

    National Aeronautics and Space Administration — Global Population Density Grid Time Series Estimates provide a back-cast time series of population density grids based on the year 2000 population grid from SEDAC's...

  1. Global Population Count Grid Time Series Estimates

    Data.gov (United States)

    National Aeronautics and Space Administration — Global Population Count Grid Time Series Estimates provide a back-cast time series of population grids based on the year 2000 population grid from SEDAC's Global...

  2. Embryonic liver cells and permanent lines as models for hepatocyte and bile duct cell differentiation.

    Science.gov (United States)

    Strick-Marchand, Hélène; Weiss, Mary C

    2003-01-01

    Analysis of liver cells during development is facilitated by the possibility of complementing in vivo analysis with experiments on cultured cells. In this review, we discuss results from several laboratories concerning bipotential hepatic stem cells from mouse (HBC-3, H-CFU-C, MMH and BMEL), rat (rhe14321) and primate (IPFLS) embryos. Several groups have used fluorescence-activated cell sorting to identify clonogenic bipotential cells; others have derived bipotential cell lines by plating liver cell suspensions and cloning. The bipotential cells, which probably originate from hepatoblasts, can differentiate as hepatocytes or bile duct cells, and undergo morphogenesis in culture. Disparities in differentiation can be explained by distinct medium compositions, extracellular matrix coated culture surfaces, and gene expression detection methods. Potential applications of these cell lines are discussed.

  3. Flood trends and population dynamics

    Science.gov (United States)

    Di Baldassarre, G.

    2012-04-01

    Since the earliest recorded civilizations, such as those in Mesopotamia and Egypt that developed in the fertile floodplains of the Tigris and Euphrates and Nile rivers, humans tend to settle in flood prone areas as they offer favorable conditions for economic development. However, floodplains are also exposed to flood disasters that might cause severe socio-economic and environmental damages not to mention losses of human lives. A flood event turns to be a disaster when it coincides with a vulnerable environment exceeding society's capacity to manage the adverse consequences. This presentation discusses the link between hydrological risk and population change by referring to the outcomes of scientific works recently carried out in Africa and Europe. More specifically, it is shown that the severity of flood disasters, currently affecting more than 100 million people a year, might be seriously exacerbated because of population change. In fact, flood exposure and/or vulnerability might increase because of rapid population growth (and its spatial and temporal dynamics, e.g. urbanization) in the African continent and because of population ageing in many European countries. Lastly, timely and economically sustainable actions to mitigate this increasing hydrological risk are critically evaluated.

  4. Population consequences of aggregative movement

    Science.gov (United States)

    Peter Turchin

    1989-01-01

    Gregarious behaviour is an important factor influencing survival and reproduction of animals, as well as population interactions. In this paper I develop a model of movement with attraction or repulsion between conspecifics. To facilitate its use in empirical studies, the model is based on experimentally measurable features of individual behaviour.

  5. Fisher population and landscape genetics

    Science.gov (United States)

    Michael Schwartz; Joel Saunder; Kristine L. Pilgrim; Ray Vinkey; Michael K. Lucid; Sean Parks; Nathan Albrecht

    2013-01-01

    This talk provides a population and landscape genetic overview of fishers in Idaho and Montana. We start by discussing some of our initial findings using mitochondrial DNA (Vinkey et al. 2006, Schwartz 2007, Knaus et al. 2011). On balance these results demonstrate the uniqueness of a native haplotype that persisted in the Bitterroot-Selway Ecosystem. They also show the...

  6. Population, Poverty, and Climate Change

    OpenAIRE

    Monica Das Gupta

    2014-01-01

    The literature is reviewed on the relationships between population, poverty, and climate change. While developed countries are largely responsible for global warming, the brunt of the fallout will be borne by the developing world, in lower agricultural output, poorer health, and more frequent natural disasters. Carbon emissions in the developed world have leveled off, but are projected to ...

  7. Measuring cancer in indigenous populations.

    Science.gov (United States)

    Sarfati, Diana; Garvey, Gail; Robson, Bridget; Moore, Suzanne; Cunningham, Ruth; Withrow, Diana; Griffiths, Kalinda; Caron, Nadine R; Bray, Freddie

    2018-02-15

    It is estimated that there are 370 million indigenous peoples in 90 countries globally. Indigenous peoples generally face substantial disadvantage and poorer health status compared with nonindigenous peoples. Population-level cancer surveillance provides data to set priorities, inform policies, and monitor progress over time. Measuring the cancer burden of vulnerable subpopulations, particularly indigenous peoples, is problematic. There are a number of practical and methodological issues potentially resulting in substantial underestimation of cancer incidence and mortality rates, and biased survival rates, among indigenous peoples. This, in turn, may result in a deprioritization of cancer-related programs and policies among these populations. This commentary describes key issues relating to cancer surveillance among indigenous populations including 1) suboptimal identification of indigenous populations, 2) numerator-denominator bias, 3) problems with data linkage in survival analysis, and 4) statistical analytic considerations. We suggest solutions that can be implemented to strengthen the visibility of indigenous peoples around the world. These include acknowledgment of the central importance of full engagement of indigenous peoples with all data-related processes, encouraging the use of indigenous identifiers in national and regional data sets and mitigation and/or careful assessment of biases inherent in cancer surveillance methods for indigenous peoples. Copyright © 2018. Published by Elsevier Inc.

  8. Better Reporting of Population Issues.

    Science.gov (United States)

    Population Education in Asia and the Pacific Newsletter and Forum, 1990

    1990-01-01

    Presented are the focus and the annotated issues from a workshop on new perspectives in population education for 19 Pacific Island journalists, both print and broadcast, from government and nongovernment agencies. The regional workshop was jointly organized by UNESCO and the South Pacific Commission during February 1990, in Auckland, New Zealand.…

  9. Attitudes on the Population Explosion

    Science.gov (United States)

    Stronck, David R.

    1971-01-01

    Attitudes of biology teachers, prospective teachers, high school students, and adults were compared in regard to the basic principles of Zero Population Growth, the teaching of controversial topics, future state of the world, and Garret Hardin's Graduated Checklist of (28) Heresies." (CP)

  10. Populism and Feminism: Odd Bedfellows.

    Science.gov (United States)

    Kroes, Rob

    2018-01-01

    In this era of populist insurgency breaking the mold of democratic politics, two movements clashed.They represented opposite sides of the political spectrum, one emancipatory, the other exclusionary. One may be identified as feminism, the other as populism. This essay analyzes both concepts and explores their connection.

  11. [Population and employment in China].

    Science.gov (United States)

    Lui, Z

    1980-04-01

    The unequal distribution of farmlands in rural areas and the extremely low productivity in the cities were the fundamental causes of unemployment and population problems in old China. Tremendous progress was made after 1949. The serious economic disturbances caused by Lin-piao and the "Gang of Four" caused great unemployment again. The slow development of China's productivity, poor business management, the involvement of women in social activities, the morality rate decrease, and the population growth rate increase are the main reasons for China's unemployment problem. The fundamental solution is to respect the objective laws of nature and economics and to develop social productivity. In the country we should implement the total development of agricultue, forestry, animal husbandry, and fishery. In towns and cities service occupations and handicraft industries should be developed, education and humanities need to be improved, and transportation, communications, and many other industries are still backward. There is high potential for development and vast opportunities for additional labor. We should constantly cultivate our high quality workforce to meet the demand of modernization. Population control is important because the higher the population growth rate the slower the accumulation of wealth. Instead of being a producer for the society the additional labor can be a burden. The vital factor in achieving the "Four Modernizations" is not the quantity of labor but the increase in productivity.

  12. Populism and Feminism : Odd Bedfellows

    NARCIS (Netherlands)

    Kroes, R.

    In this era of populist insurgency breaking the mold of democratic politics, two movements clashed.They represented opposite sides of the political spectrum, one emancipatory, the other exclusionary. One may be identified as feminism, the other as populism. This essay analyzes both concepts and

  13. Measuring senescence in human populations

    NARCIS (Netherlands)

    Koopman, Jacob Jan Egbert

    2015-01-01

    In this thesis, senescence is measured in human populations according to its definition of an increase in the risks of dysfunction, disease, and death with chronological age. Part I of this thesis investigates how a population’s senescence rate can be measured through the increase in mortality rate

  14. Gender, Education and Population Flows

    DEFF Research Database (Denmark)

    Bennike, Kathrine Bjerg; Faber, Stine Thidemann; Nielsen, Helene Pristed

    During the Danish Presidency for the Nordic Council of Ministers in 2015, attention was drawn towards challenges and best practice examples in relation to gender, education and population flows in peripheral areas throughout the Nordic countries - Norway, Denmark, Sweden, Finland, Iceland...

  15. Reproductive effort in viscous populations

    NARCIS (Netherlands)

    Pen, Ido

    Here I study a kin selection model of reproductive effort, the allocation of resources to fecundity versus survival, in a patch-structured population. Breeding females remain in the same patch for life. Offspring have costly, partial long-distance dispersal and compete for breeding sites, which

  16. Population message from the village.

    Science.gov (United States)

    Hibler, M

    1979-06-01

    According to a number of participants at the population conference in Ontario, sponsored by the School of Journalism of the Univesity of Western Ontario and the Canadian International Development Agency, the villages, in developing countries, have sent a message to population experts, declaring that the most effective way to motivate individuals toward reducing family size is to improve basic educational and health care services. It has been demonstrated that improvements in these areas, by providing women with educational opportunities and by reducing infant mortality, have a direct impact on fertility. Efforts should be directed toward discovering similar direct correlates. The message dismissed as irrelevant the battle raging between those who advocate that population growth must be halted before poverty can be eliminated, between the developmentalists, who believe that fundamental changes in economic and political conditions will automatically solve the population problem, and between those who declare that family planning and development must be dealt with simultaneously for either to be effective. Despite evidence demonstrating the effectiveness of the 'direct correlate' approach, most developing countries continue to accord top priority to family planning programs and neglect educational and health care services.

  17. Population entropies estimates of proteins

    Science.gov (United States)

    Low, Wai Yee

    2017-05-01

    The Shannon entropy equation provides a way to estimate variability of amino acids sequences in a multiple sequence alignment of proteins. Knowledge of protein variability is useful in many areas such as vaccine design, identification of antibody binding sites, and exploration of protein 3D structural properties. In cases where the population entropies of a protein are of interest but only a small sample size can be obtained, a method based on linear regression and random subsampling can be used to estimate the population entropy. This method is useful for comparisons of entropies where the actual sequence counts differ and thus, correction for alignment size bias is needed. In the current work, an R based package named EntropyCorrect that enables estimation of population entropy is presented and an empirical study on how well this new algorithm performs on simulated dataset of various combinations of population and sample sizes is discussed. The package is available at https://github.com/lloydlow/EntropyCorrect. This article, which was originally published online on 12 May 2017, contained an error in Eq. (1), where the summation sign was missing. The corrected equation appears in the Corrigendum attached to the pdf.

  18. Whither the global population problem.

    Science.gov (United States)

    Greep, R O

    1998-02-15

    Growth of the human population has been underway for thousands of years and was never a problem until recently. It is now expanding exponentially, and today global population stands at nearly 6 billion with 97 million being added each year. Currently, overpopulation has led to serious social and environmental problems such as poverty, overcrowded slums, crime, terrorism, pollution of air and water, and depletion of the protective ozone layer. Warnings were sounded, but few listened. The enthusiasm once generated for solving the problem of too many people was short-lived. The press with puzzling abrogation of its responsibility to the public managed to allay all fears of population overgrowth. Two U.S. presidents welcomed such growth as a stimulus to economic development. Although modern contraceptives are safe, effective, and widely available, more are badly needed, but none are in the pipeline. Research is being hampered by hostile attitudes and by the high cost in time and money of bringing a new contraceptive to an uncertain market with the added threat of litigation. At the present rate of growth, the population will double in the next century. This is believed to be beyond the carrying capacity of our planet. Corrective measures by man or nature need to be undertaken.

  19. Disability in Singapore's Elderly Population.

    Science.gov (United States)

    Mahesh, Mithila; Abdin, Edimansyah; Vaingankar, Janhavi Ajit; Picco, Louisa; Jeyagurunathan, Anita; Shafie, Saleha Binte; Pang, Shirlene; Sagayadevan, Vathsala; Seow, Esmond; Chong, Siow Ann; Subramaniam, Mythily

    2016-07-01

    Disability increases an individual's dependence and negatively impacts their physical, mental, and social functioning. The current study aims to establish the prevalence and risk factors of disability in Singapore's population. Data was extracted from the Well-being of the Singapore Elderly (WiSE) study. This cross-sectional study recruited participants aged 60 years and above (n = 2421) who were representative of Singapore's multiethnic population. We used the World Health Organization Disability Assessment Schedule (WHODAS) 2.0 to assess the severity of disability in our sample while establishing its associations and correlations with cognitive levels, sociodemographic variables, and chronic illness. Cognitive deficits, old age, female gender, Malay and Indian ethnicity, lack of education, retired or homemaker status, presence of chronic illness (specifically stroke, heart problems, depression, and dementia) were found to be significantly associated with disability in Singapore's elderly population. As hypothesised, participants with deficits in cognition were more likely to indicate higher WHODAS scores. The findings highlighted specific factors associated with disability in this multiethnic population. The identification of these factors would lead the way to the development of appropriate interventions.

  20. Population and the Colombian economy.

    Science.gov (United States)

    Sanders, T G

    1983-01-01

    Colombia is the only one of the 6 most populous Latin American countries that is currently free of major economic crisis requiring an agreement with the International Monetary Fund. The difference in the economic performances of these countries is relative, since the rate of growth in the Colombian economy was only 1.5% in 1982. Yet, Colombia seems to have weathered the international recession better than most. The crisis atmosphere in the rest of Latin America, triggered by overall economic decline, high rates of inflation, and an indebtedness that soaks up much of export earnings to service it, is lacking in Colombia or present in lesser degree. If Colombia can strengthen its political performance and tighten national unity, it could move through the 1980s with considerable confidence and success in economic development. Colombia differs little from other major Latin American countries with regard to traditionalism and modernization. Most Colombians are secularized. Colombia is far ahead of most comparable Latin American countries in fertility control. The lower rate of population increase defines the extent to which the economy must provide education, health, food, and jobs. 2 other factors are essential for understanding the current situation in Colombia and its prospects for the 1980s. Government policy in the 1970s opted for an austerity program while the other countries were growing rapidly, in large part through borrowed resources. A 2nd factor is the prospect of attaining autonomy in energy production. These special characteristics--population, public policy, and energy--are discussed. Since the mid 1960s Colombia has functioned with 3 family planning programs. Their existence makes contraception easily available to the population generally. In 1960 Colombia had a higher total fertility rate (TFR) 7.0, than either Venezuela (6.6) or Brazil (5.3), but by 1976 its TFR was down to 4.1, while Venezuela's (4.8) and Brazil's (4.3) were now higher. On balance

  1. [Comments on population and ecology].

    Science.gov (United States)

    Negrette, J C

    1990-12-01

    Concern about the condition of the environment and about rapid population growth has a long history. The breadth and magnitude of present day concern may perhaps represent a new development even though the topics themselves are not new. There is almost no country or society that has not manifested disquiet about 1 or the other. Ecology in the strict sense is defined as the relationship between organisms and their environment. In recent decades ecology has come to understood as the manner of avoiding or slowing environmental deterioration or even as the correct and prudent administration of natural resources. The boundaries of the discipline have expanded until today it is concerned with various spheres of the natural and social sciences. The transformations wrought by human beings have been dramatic, both because the use of tools had increased the power of human modification of the environment and because the human population is large and spread over the whole world. Human beings have been responsible for some ecologic disasters, some unintentional like the Exxon Valdez and Chernobyl accidents and others the perhaps unforseen results of deliberate actions, as the contamination of the atmosphere with gas emissions. Environmental deterioration can result from numerous causes, as with the "greenhouse effect" caused by a range of factors including classical contamination and deforestation. Deforestation in developing countries is a response to the combination of poverty and rapid population growth, and is 1 evidence of the close and direct link between population growth and the condition of the environment. The optimism felt during the 1970s about the prospects of bringing world population growth under control has given way to a more realistic and sobering assessment. Many factors including widespread economic difficulties have impeded the progress of family planning programs. It is urgent that efforts to curb rapid population increase be intensified. 1 important means

  2. Population momentum: Implications for wildlife management

    Science.gov (United States)

    Koons, D.N.; Rockwell, R.F.; Grand, J.B.

    2006-01-01

    Maintenance of sustainable wildlife populations is one of the primary purposes of wildlife management. Thus, it is important to monitor and manage population growth over time. Sensitivity analysis of the long-term (i.e., asymptotic) population growth rate to changes in the vital rates is commonly used in management to identify the vital rates that contribute most to population growth. Yet, dynamics associated with the long-term population growth rate only pertain to the special case when there is a stable age (or stage) distribution of individuals in the population. Frequently, this assumption is necessary because age structure is rarely estimated. However, management actions can greatly affect the age distribution of a population. For initially growing and declining populations, we instituted hypothetical management targeted at halting the growth or decline of the population, and measured the effects of a changing age structure on the population dynamics. When we changed vital rates, the age structure became unstable and population momentum caused populations to grow differently than that predicted by the long-term population growth rate. Interestingly, changes in fertility actually reversed the direction of short-term population growth, leading to long-term population sizes that were actually smaller or larger than that when fertility was changed. Population momentum can significantly affect population dynamics and will be an important factor in the use of population models for management.

  3. [Population: evolution of Rwandan attitudes or the adaptation of the Rwanda population to population growth].

    Science.gov (United States)

    Ngendakumana, M

    1988-04-01

    A consequence of the increasing pressure on Rwanda's ecosystem resulting from population growth has been that demographic factors have played a significant role in modifying attitudes and beliefs of the population. The history of Rwanda demonstrates a constant struggle for survival in the face of increasing population pressure. Migration, colonization of new agricultural lands, adoption of new crops and new forms of animal husbandry have been responses to population pressures. Recent unprecedented population growth has exceeded the capacity of older systems of cultivation and combinations of agricultural and animal husbandry to support the population. Smaller animals have largely replaced the cattle that once roamed freely in extensive pastures, and new techniques of stabling animals, use of organic or chemical fertilizers, and new tools adapted to the shrinking size of farm plots have represented responses to the new demographic realities. The concept of the family is likewise undergoing modification in the face of population growth and modernization. Children, who once were valued as a source of labor and constrained to conform to the wishes of the parents in return for the eventual inheritance of the goods and livelihood, now increasingly look beyond the household for education and employment. Family land holdings have become too small to support all the members with a claim on them. The greater distances between family members inevitably mean that relations between them lose closeness. The choice of a marriage partner is increasingly assumed by the young people themselves and not by their families. Old traditions of food sharing and hospitality have been curtailed because of the increasing scarcity of food. Despite the changes engendered by increasing population pressure, pronatalist sentiments are still widespread. But the desire to assure the future of each child rather than to await his services, a new conception of women less dependent on their reproductive

  4. Pharmacogenetics in the Brazilian population

    Directory of Open Access Journals (Sweden)

    Guilherme eSuarez-Kurtz

    2010-10-01

    Full Text Available Brazil is the 5th largest country in the world and its present population, in excess of 190 million, is highly heterogeneous, as a result of centuries of admixture between Amerindians, Europeans and Sub-Saharan Africans. The estimated individual proportions of biogeographical ancestry vary widely and continuously among Brazilians, most individuals - irrespective of self-identification as White, Brown or Black, the major categories of the Brazilian Census race/color system - having significant degrees of European and African ancestry, while a sizeable number display also Amerindian ancestry. These features have important pharmacogenetic (PGx implications: first, extrapolation of PGx data from relatively well-defined ethnic groups is clearly not applicable to the majority of Brazilians; second, the frequency distribution of polymorphisms in pharmacogenes (e.g. CYP3A5, CYP2C9, GSTM1, ABCB1, GSTM3, VKORC, etc varies continuously among Brazilians and is not captured by race/color self-identification; third, the intrinsic heterogeneity of the Brazilian population must be acknowledged in the design and interpretation of PGx studies in order to avoid spurious conclusions based on improper matching of study cohorts. The peculiarities of PGx in Brazilians are illustrated with data for different therapeutic groups, such as anticoagulants, HIV-protease inhibitors and nonsteroidal antinflammatory drugs, and the challenges and advantages created by population admixture for the study and implementation of PGx are discussed. PGx data for Amerindian groups and Brazilian-born, first generation Japanese are presented to illustrate the rich diversity of the Brazilian population. Finally, I introduce the reader to the Brazilian Pharmacogenetic Network or Refargen (www.refargen.org.br, a nationwide consortium of research groups, with the mission to provide leadership in PGx research and education in Brazil, with a population health impact.

  5. Philippine president announces population policy.

    Science.gov (United States)

    1970-02-01

    President Ferdinand Marcos of the Philippines has announced a national policy for family planning, following his recent reelection for a second term of office. Under the policy adopted by the President, the Philippine Government is committed to undertake and encourage programs to provide information and advice for couples wishing to space or limit their child-bearing activities. The Presidential Commission on Population, in a report based on recommendations drawn up after more than 20 meetings by the 22 members, and states that the unfettered population growth will gravely hamper efforts to improve living standards for Filipinos and will block the attainment of national development goals. However, the Commission emphasized that the program will be educational and persuasive, not coercive. Family planning services have been growing rapidly in the Philippines over the past few years as a result of the initiative of several pioneer organizations assisted by the IPPF. President Marcos' government signed the United Nations Declaration on Population in 1967 and in January 1969 he established The Commission on Population. The Philippine press has consistently backed the campaign for widespread availability of family planning services. The Western Pacific Region of the World Health Organization, under it's Director, Dr. Francisco Dy, which has its headquarters in Manila, has its headquarters in Manila, has fostered a regional interest through its technical discussions and the training of field personnel. Depthnews recently reported that the latest Philippine demographic survey asserts that Filipina women are bearing children so fast that the country will hold on to the undisputed title of possessing the highest birth rate in Asia. The growth rate is 3.5%, and the average completed size of a Filipino family is 6.8 children. This swift rate of growth will boost the 1969 population of 37.1 million to 38.4 at the end of this decade. It is noted that unless curbed, it will

  6. Pharmacogenetics in the brazilian population.

    Science.gov (United States)

    Suarez-Kurtz, Guilherme

    2010-01-01

    Brazil is the fifth largest country in the world and its present population, in excess of 190;million, is highly heterogeneous, as a result of centuries of admixture between Amerindians, Europeans, and Sub-Saharan Africans. The estimated individual proportions of biogeographical ancestry vary widely and continuously among Brazilians: most individuals, irrespective of self-identification as White, Brown or Black - the major categories of the Brazilian Census "race/color" system - have significant degrees of European and African ancestry, while a sizeable number display also Amerindian ancestry. These features have important pharmacogenetic (PGx) implications: first, extrapolation of PGx data from relatively well-defined ethnic groups is clearly not applicable to the majority of Brazilians; second, the frequency distribution of polymorphisms in pharmacogenes (e.g., CYP3A5, CYP2C9, GSTM1, ABCB1, GSTM3, VKORC, etc) varies continuously among Brazilians and is not captured by race/color self-identification; third, the intrinsic heterogeneity of the Brazilian population must be acknowledged in the design and interpretation of PGx studies in order to avoid spurious conclusions based on improper matching of study cohorts. The peculiarities of PGx in Brazilians are illustrated with data for different therapeutic groups, such as anticoagulants, HIV protease inhibitors and non-steroidal antinflammatory drugs, and the challenges and advantages created by population admixture for the study and implementation of PGx are discussed. PGx data for Amerindian groups and Brazilian-born, first-generation Japanese are presented to illustrate the rich diversity of the Brazilian population. Finally, I introduce the reader to the Brazilian Pharmacogenetic Network or Refargen, a nation-wide consortium of research groups, with the mission to provide leadership in PGx research and education in Brazil, with a population health impact.

  7. The human placenta is a hematopoietic organ during the embryonic and fetal periods of development

    Science.gov (United States)

    Bárcena, Alicia; Kapidzic, Mirhan; Muench, Marcus O.; Gormley, Matthew; Scott, Marvin A.; Weier, Jingly F.; Ferlatte, Christy; Fisher, Susan J.

    2008-01-01

    We studied the potential role of the human placenta as a hematopoietic organ during embryonic and fetal development. Placental samples contained two cell populations—CD34++CD45low and CD34+CD45low—that were found in chorionic villi and in the chorioamniotic membrane. CD34++CD45low cells express many cell surface antigens found on multipotent primitive hematopoietic progenitors and hematopoietic stem cells. CD34++CD45low cells contained colony-forming units culture (CFU-C) with myeloid and erythroid potential in clonogenic in vitro assays, and they generated CD56+ natural killer cells and CD19+CD20+sIgM+ B cells in polyclonal liquid cultures. CD34+CD45low cells mostly comprised erythroid- and myeloid-committed progenitors, while CD34− cells lacked CFU-C. The placenta-derived precursors were fetal in origin, as demonstrated by FISH using repeat-sequence chromosome-specific probes for X and Y. The number of CD34++CD45low cells increased with gestational age, but their density (cells per gram of tissue) peaked at 5–8 wk, decreasing more than sevenfold at the onset of the fetal phase (9 wk of gestation). In addition to multipotent progenitors, the placenta contained myeloid- and erythroid-committed progenitors indicative of active in situ hematopoiesis. These data suggest that the human placenta is an important hematopoietic organ, raising the possibility of banking placental hematopoietic stem cells along with cord blood for transplantation. PMID:19073167

  8. "India Population Projects" in Karnataka.

    Science.gov (United States)

    Reddy, P H; Badari, V S

    1991-12-01

    An overview, objectives, implementation, and research and evaluation studies of 2 India Population Projects in Karnataka are presented. The India Population Project I (IPP-I) was conducted in Karnataka and Uttar Pradesh. India Population Project III (IPP-III) took place between 1984-92 in 6 districts of Karnataka: Belgaum, Bijapur, Dharwad, Bidar, Gulbarga, and Raichur, and 4 districts in Kerala. The 6 districts in Karnataka accounted for 36% (13.2 million) of the total national population. The project cost was Rs. 713.1 million which was shared by the World Bank, and the Indian national and regional government. Due to poor past performance, these projects were undertaken to improve health and family welfare status. Specific project objectives are outlined. IPP-I included an urban component, and optimal Government of India program, and an intensive rural initiative. The urban program aimed to improved pre- and postnatal services and facilities, and the family planning (FP) in Bangalore city. The rural program was primarily to provide auxiliary nurse-midwives and hospitals and clinics, and also supplemental feeding program for pregnant and nursing mothers and children up to 2 years. The government program provided FP staff and facilities. IPP-I had 3 units to oversee building construction, to recruit staff and provide supplies and equipment, and to establish a Population Center. IPP-III was concerned with service delivery; information, education, and communication efforts (IEC) and population education; research and evaluation; and project management. Both projects contributed significantly to improving the infrastructure. A brief account of the types and kinds of studies undertaken is given. Studies were grouped into longitudinal studies of fertility, mortality, and FP; management information and evaluation systems for health and family welfare programs; experimental strategies; and other studies. Research and evaluation studies in IPP-III encompassed studies in

  9. GPU accelerated population annealing algorithm

    Science.gov (United States)

    Barash, Lev Yu.; Weigel, Martin; Borovský, Michal; Janke, Wolfhard; Shchur, Lev N.

    2017-11-01

    Population annealing is a promising recent approach for Monte Carlo simulations in statistical physics, in particular for the simulation of systems with complex free-energy landscapes. It is a hybrid method, combining importance sampling through Markov chains with elements of sequential Monte Carlo in the form of population control. While it appears to provide algorithmic capabilities for the simulation of such systems that are roughly comparable to those of more established approaches such as parallel tempering, it is intrinsically much more suitable for massively parallel computing. Here, we tap into this structural advantage and present a highly optimized implementation of the population annealing algorithm on GPUs that promises speed-ups of several orders of magnitude as compared to a serial implementation on CPUs. While the sample code is for simulations of the 2D ferromagnetic Ising model, it should be easily adapted for simulations of other spin models, including disordered systems. Our code includes implementations of some advanced algorithmic features that have only recently been suggested, namely the automatic adaptation of temperature steps and a multi-histogram analysis of the data at different temperatures. Program Files doi:http://dx.doi.org/10.17632/sgzt4b7b3m.1 Licensing provisions: Creative Commons Attribution license (CC BY 4.0) Programming language: C, CUDA External routines/libraries: NVIDIA CUDA Toolkit 6.5 or newer Nature of problem: The program calculates the internal energy, specific heat, several magnetization moments, entropy and free energy of the 2D Ising model on square lattices of edge length L with periodic boundary conditions as a function of inverse temperature β. Solution method: The code uses population annealing, a hybrid method combining Markov chain updates with population control. The code is implemented for NVIDIA GPUs using the CUDA language and employs advanced techniques such as multi-spin coding, adaptive temperature

  10. Stochastic problems in population genetics

    CERN Document Server

    Maruyama, Takeo

    1977-01-01

    These are" notes based on courses in Theoretical Population Genetics given at the University of Texas at Houston during the winter quarter, 1974, and at the University of Wisconsin during the fall semester, 1976. These notes explore problems of population genetics and evolution involving stochastic processes. Biological models and various mathematical techniques are discussed. Special emphasis is given to the diffusion method and an attempt is made to emphasize the underlying unity of various problems based on the Kolmogorov backward equation. A particular effort was made to make the subject accessible to biology students who are not familiar with stochastic processes. The references are not exhaustive but were chosen to provide a starting point for the reader interested in pursuing the subject further. Acknowledgement I would like to use this opportunity to express my thanks to Drs. J. F. Crow, M. Nei and W. J. Schull for their hospitality during my stays at their universities. I am indebted to Dr. M. Kimura...

  11. Environmental impact of population growth

    Science.gov (United States)

    Naylor, Rosamond; Matson, Pamela

    Earth's population currently numbers 5.4 billion; even given optimistic assumptions for reduction in growth rates, the number will double by the middle of the next century with most of the increase in the developing countries. Rapid population growth in the developing world raises the fundamental dilemma of how to alleviate chronic hunger and poverty in the short run while preserving the atmosphere and ecosystem services required for long-term human and biospheric sustenance. This dilemma, and the compromises required to solve it, were discussed by twenty-five researchers from five countries at the Aspen Global Change Institute 1992 Summer Science Session III, Food, Conservation, and Global Environmental Change: Is Compromise Possible?, held from August 16 to 28, in Aspen, Colo.

  12. Statistical thermodynamics of clustered populations.

    Science.gov (United States)

    Matsoukas, Themis

    2014-08-01

    We present a thermodynamic theory for a generic population of M individuals distributed into N groups (clusters). We construct the ensemble of all distributions with fixed M and N, introduce a selection functional that embodies the physics that governs the population, and obtain the distribution that emerges in the scaling limit as the most probable among all distributions consistent with the given physics. We develop the thermodynamics of the ensemble and establish a rigorous mapping to regular thermodynamics. We treat the emergence of a so-called giant component as a formal phase transition and show that the criteria for its emergence are entirely analogous to the equilibrium conditions in molecular systems. We demonstrate the theory by an analytic model and confirm the predictions by Monte Carlo simulation.

  13. Modern pesticides and bobwhite populations

    Science.gov (United States)

    Stromborg, K.L.; Schitoskey, Frank=; Schitoskey, Elizabeth C.; Talent, Larry G.

    1982-01-01

    Bobwhite (Colinus virginianus) are frequently used as test animals for wildlife tests of pesticides. The organophosphate and carbamate pesticides that have replaced the organochlorines have many desirable properties, but they span a wide range of acute toxicities and some of them affe,ct survival, reproduction, food consumption, behavior, and nervous system enzymes in laboratory tests. Applying these laboratory findings to the field requires assumptions about the severity of exposure in the field. Direct field measurements show that birds may be exposed to significant amounts of these pesticides or even more toxic degradation products under some conditions. Adverse population effects may also result from depression of insect populations during the seasons when bobwhites rely on insects for food.

  14. Dynamical systems in population biology

    CERN Document Server

    Zhao, Xiao-Qiang

    2017-01-01

    This research monograph provides an introduction to the theory of nonautonomous semiflows with applications to population dynamics. It develops dynamical system approaches to various evolutionary equations such as difference, ordinary, functional, and partial differential equations, and pays more attention to periodic and almost periodic phenomena. The presentation includes persistence theory, monotone dynamics, periodic and almost periodic semiflows, basic reproduction ratios, traveling waves, and global analysis of prototypical population models in ecology and epidemiology. Research mathematicians working with nonlinear dynamics, particularly those interested in applications to biology, will find this book useful. It may also be used as a textbook or as supplementary reading for a graduate special topics course on the theory and applications of dynamical systems. Dr. Xiao-Qiang Zhao is a University Research Professor at Memorial University of Newfoundland, Canada. His main research interests involve applied...

  15. Cancer patterns in Inuit populations

    DEFF Research Database (Denmark)

    Melbye, M.; Friborg, Jeppe Tang

    2008-01-01

    to be responsible for this pattern. During the second half of the 20th century, Inuit societies underwent major changes in lifestyle and living conditions, and the risk of lifestyle-associated tumours, especially cancers of the lung, colon, and breast, increased considerably after changes in smoking, diet......, and reproductive factors. This Review will briefly summarise the current knowledge on cancer epidemiology in Inuit populations, with emphasis on the characteristic Inuit types of cancer Udgivelsesdato: 2008/9...... a distinct pattern, characterised by a high risk of Epstein-Barr virus-associated carcinomas of the nasopharynx and salivary glands, and a low risk of tumours common in white populations, including cancer of the prostate, testis, and haemopoietic system. Both genetic and environmental factors seem...

  16. Population growth can be checked.

    Science.gov (United States)

    Shukla, J P

    Since independence, India's population size has doubled. The rate of growth was 2.5% during 1971-81, an increase from the rate of 2.15% observed during the 1951-61 period. The increase indicated that efforts to decrease population growth have not succeeded. The implications with respect to food, housing, clothing, education, and health facilities, which are fundamental to improving the physical quality of life, are severe. This demographic trend is a serious impediment to progress. The population growth is due to a constant birthrate and a sharp decline in mortality. Reducing the birthrate is necessary to reduce the rate of growth. An attitudinal change adopting the norm of family limitation should be encouraged through propaganda, socioeconomic programs, and religious and cultural organizations. Other measures to bring about a decline in the birthrate include: increasing the marriage age, and expanding educational and employment opportunities for women and girls. These measures will require substantial effort and time. Incentives may show more immediate effects. Monetary incentives are not desired because of the possibility of misuse. However the government could assume responsibility for the education and guarantee employment of children of couples who have only one child, and provide free education to children of couples with only 2 children. These incentives are not likely to be misused, can be available to all segments of the population, and involve no immediate large financial burden on the government. In addition, scholarships to the Harijan students should be limited to 2 per family. If these measures are accepted, they could quickly reduce the birth rate.

  17. World Population Day special symposium.

    Science.gov (United States)

    1998-08-01

    This article describes Japan's celebration of World Population Day, and provides excerpts from speeches at the symposium held on July 8, 1998. The symposium, in Tokyo, was attended by about 300 people. The Chairman of JOICFP gave the opening address. The executive director of UNFPA congratulated Japan for its efforts in the field of population awareness and noted Japan's self-sufficiency despite its importation of 40% of its food and most of its raw materials. A keynote address was delivered by the president of CPE and the former UN Secretary General, who stressed income inequities in the 66% of developing countries within the 185 UN member states. The UN has been promoting sustainable development, but is facing the issue of limited arable land and population growth. The Tutsi and Hutus are fighting due to population based issues. The emphasis should be on women's reproductive rights and protection of women's human rights. 1998 is the 50th year of human rights; progress has been made. The UNFPA Goodwill Ambassador spoke about the disparity between the rich and poor in the Philippines. A small donation reaps incredible progress. Manila has high levels of adolescent childbearing. Men appear to be unaware of the disadvantages of childbearing too early. Rural areas are dominated by strict Roman Catholic beliefs. Manila has commercial sex workers who provide services to Japanese men. The 1998 Kato Award was given to women who raised awareness about coercion in the sex trade and female genital mutilation. The economic situation in Japan creates even greater need to promote family planning and reproductive health.

  18. New population law for Mexico.

    Science.gov (United States)

    1974-02-01

    A bill of additions and reforms to Mexico's General Law on Population, which established a legal framework for planned parenthood programs as part of a general development policy, set guidelines for the protection of human rights in public and private programs, and dealt with migration, immigration, emigration, and repatriation, was announced initially by Mexican President Luis Echeverria as one step toward reducing Mexico's 3.5% annual rate of growth. The legislation became law on January 7, 1974.

  19. a population-based study

    OpenAIRE

    Gholami, Mahdia; Pakdaman, Afsaneh; Montazeri, Ali; Jafari, Ahmad; Virtanen, Jorma I.

    2014-01-01

    Background Oral health promotion can be achieved through education using various approaches including mass media health education campaigns. Mass media campaigns might increase oral health knowledge and perhaps could lead to desired behaviour changes and prevention of oral diseases. The aim of this study was to assess the effect of a national television campaign on knowledge of periodontal health among Iranian adults. Methods We conducted a population-based survey among adults aged 18–50 usin...

  20. Population growth and economic development.

    Science.gov (United States)

    Corbridge, S

    1989-01-01

    The Malthusian and neo-Malthusian approaches to the role of population growth in economic development and resource depletion are briefly outlined. Three arguments are then presented that emphasize demographic determinism, empirical evidence, and cause and effect. The author concludes that non-coercive family planning programs may have a role to play in countries that are unable to reduce inequalities, particularly for the poor and for women.

  1. Endogenous Population and Environmental Quality

    OpenAIRE

    Phu NGUYEN VAN

    2002-01-01

    This paper provides with empirical and theoretical studies of the relationship between population, economic growth and environmental quality. Using a simple endogenous growth model we obtain results close to empirical findings. We show existence of a sustainable balanced growth path (BGP) equilibrium in which perpetual economic growth goes in parallel with environmental quality preservation. At the BGP equilibrium, when all exogenous factors are controlled, a negative relationship between fer...

  2. From Population to Organization Thinking

    OpenAIRE

    Lane, David; Maxfield, Robert; Read, Dwight W; van der Leeuw, Sander E

    2009-01-01

    This chapter begins by reviewing the Darwinian account of biological innovation, which is based on what Ernst Mayr calls “population thinking” and posits two kinds of key mechanisms underlying the innovation process, variation and selection. The chapter then argues that the increasingly popular tendency to adapt this account to provide the foundations for a theory of human sociocultural innovation is ill-advised. Human sociocultural organizations are self-reflexive and self-modifying, through...

  3. Population mobility in Peninsular Malaysia.

    Science.gov (United States)

    Jones, G W; Sidh, M S

    1979-12-01

    1970 census materials were used to analyze migration patterns in Peninsular Malaysia. Inter-state migration patterns were analyzed by comparing birth place and current place of residence data, and inter-district and intra-district migration patterns were assessed using information on previous and current place of residence. The proportion of inter-state migrants in the total population increased from 4.7%-10.9% from 1947-1970. 53% of the inter-state migrants were Malays, 33% were Chinese, and 13% were Indian. The states of Selangor and Pahang had the highest net migration gains and Perak had the highest number of out-migrants. Selangor attracted migrants because it was a major industrial, administrative and educational center. Migrants were attracted to Pahang because of recent efforts by the government to promote agricultural development in the state. Areas which showed a net migration loss were experiencing slow economic growth. 48.4% of the inter-state migrants migrated to either rural or suburban areas, 26% moved to cities with populations of 75,000 or more, and 26% moved to towns with populations of 1000-10,000. 48.6% of the inter-state migrants were females. When all types of internal migration were taken into account it was estimated that approximately 30% of the population had moved at some point in their life time. During the early 1900s, Peninsular Malaysia received many immigrants from China, India, and other countries, and the Chinese became the dominant group in many urban areas and in many economic sectors. In 1950 the government, fearing that the Malays would become a minority group in their own country, halted international immigration. The recent increase in internal migration has contributed toward equalizing the influence and power of the Chinese and the Malays in urban areas and in various economic sectors.

  4. Incorporating territory compression into population models

    NARCIS (Netherlands)

    Ridley, J; Komdeur, J; Sutherland, WJ; Sutherland, William J.

    The ideal despotic distribution, whereby the lifetime reproductive success a territory's owner achieves is unaffected by population density, is a mainstay of behaviour-based population models. We show that the population dynamics of an island population of Seychelles warblers (Acrocephalus

  5. 45 CFR 1356.81 - Reporting population.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 4 2010-10-01 2010-10-01 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...

  6. NIDI scenario. Strong population decline in China

    NARCIS (Netherlands)

    de Beer, J.A.A.

    2016-01-01

    United Nations projections assume that by the end of this century one third of the world population will live in India, China or Nigeria. While population growth in India will slow down and the population size of China will decline, population growth in Nigeria will accelerate. A new NIDI scenario

  7. Developing Education Programs or Population Awareness.

    Science.gov (United States)

    Viederman, Stephen

    Speakers on population matters often refer to the population explosion with an air of crisis. It is questionable that images of doomsday are defensible for us in our role as educators. The goals of population education are to develop an understanding of the impacts of population characteristics on national development, as well as their impact on…

  8. Role of women in population.

    Science.gov (United States)

    Srivasdava, T N

    Population control through voluntary adoption of family planning is emphasized in India's family planning policy. The 1981 census figures have not shown an arresting rate of population growth. The social and attitudinal barriers to promoting the concept of the small family are great where men and women are not exposed to new ideas. The target groups for family planning include the 75% of the population residing in rural areas. The literacy rate for women in rural areas in 1971 was 18.69. Motivation is difficult unless supported by systematic education. Women play an important role in the determination of family size. Participation in social and economic activities may help to promote small family size by meeting the necessary conditions of emotional and social fulfillment of women outside the family context. Adquate education for women in rural as well as urban areas can elucidate alternatives to childbearing and enable women to appreciate the need for and use of contraception. Employment opportunities enhance women's familial decision making power through the acquisition of an alternative social and economic role, which may help them to adopt birth control practices, space their children, and limit family size. Motivational schemes may change the attitudes of a small number of families, however, greater gains could be achieved through an investment in women's education and employment.

  9. Population issues in clinical trials.

    Science.gov (United States)

    Mosenifar, Zab

    2007-05-01

    Inclusion of underrepresented groups in clinical trials is important for several reasons. Age, sex, race, genetic factors, concomitant use of other medications, and comorbid conditions all may play pivotal roles in response to a drug or intervention. Despite the legislation for broader inclusion of underrepresented groups in clinical trials (via the National Institutes of Health [NIH] Revitalization Act of 1993), underrepresentation of particular populations, particularly minorities, continues to be a problem. Studies of predictors of clinical trial enrollment suggest that most people participate in clinical research to find relief from a disease, not for financial remuneration. Yet, men and whites are more likely to enroll in studies and some data indicate that certain patient populations are preferentially (albeit sometimes inadvertently) chosen for study enrollment. This tendency toward inclusion stems from human nature-the natural tendency for an investigator to relate to a particular investigative topic due to a special connection based on a cultural, socioeconomic, age, ethnicity, or gender level. This article reviews the most common population issues for clinical studies: age, gender, race, socioeconomic status, comorbidities, and disease severity, with examples of each from published studies. Recommendations are also offered to overcome these barriers.

  10. Population growth and global warming

    Science.gov (United States)

    Short, R.V.

    2009-01-01

    When I was born in 1930, the human population of the world was a mere 2 billion. Today, it has already reached 6.8 billion, and is projected to reach 9.1 billion by 2050. That is unsustainable. It is slowly beginning to dawn on us that Global Warming is the result of increasing human CO2 emissions, and the more people there are in the world, the worse it will become. Ultimately, it is the sky that will prove to be the limit to our numbers. The developed countries of the world are the most affluent, and also the most effluent, so we must lead by example and contain our own population growth and per capita emissions. We also have a big debt to repay to former colonial territories in Africa, Asia and South America, who desperately need our help to contain their excessive rates of population growth. Belgian and Dutch obstetricians and gynaecologists can play a critical role in this endeavour. After all, we already have a pill that will stop global warming – the oral contraceptive pill. PMID:25478068

  11. FSPS: Flexible Stellar Population Synthesis

    Science.gov (United States)

    Conroy, Charlie; Gunn, James E.

    2010-10-01

    FSPS is a flexible SPS package that allows the user to compute simple stellar populations (SSPs) for a range of IMFs and metallicities, and for a variety of assumptions regarding the morphology of the horizontal branch, the blue straggler population, the post-AGB phase, and the location in the HR diagram of the TP-AGB phase. From these SSPs the user may then generate composite stellar populations (CSPs) for a variety of star formation histories (SFHs) and dust attenuation prescriptions. Outputs include the "observed" spectra and magnitudes of the SSPs and CSPs at arbitrary redshift. In addition to these fortran routines, several IDL routines are provided that allow easy manipulation of the output. FSPS was designed with the intention that the user would make full use of the provided fortran routines. However, the full FSPS package is quite large, and requires some time for the user to become familiar with all of the options and syntax. Some users may only need SSPs for a range of metallicities and IMFs. For such users, standard SSP sets for several IMFs, evolutionary tracks, and spectral libraries are available here.

  12. Population growth and global warming.

    Science.gov (United States)

    Short, R V

    2009-01-01

    When I was born in 1930, the human population of the world was a mere 2 billion. Today, it has already reached 6.8 billion, and is projected to reach 9.1 billion by 2050. That is unsustainable. It is slowly beginning to dawn on us that Global Warming is the result of increasing human CO2 emissions, and the more people there are in the world, the worse it will become. Ultimately, it is the sky that will prove to be the limit to our numbers. The developed countries of the world are the most affluent, and also the most effluent, so we must lead by example and contain our own population growth and per capita emissions. We also have a big debt to repay to former colonial territories in Africa, Asia and South America, who desperately need our help to contain their excessive rates of population growth. Belgian and Dutch obstetricians and gynaecologists can play a critical role in this endeavour. After all, we already have a pill that will stop global warming - the oral contraceptive pill.

  13. Population change, resources and environment.

    Science.gov (United States)

    1982-06-01

    Environmental pollution is a problem of crisis proportions in today's world, presently more visible in technologically advanced than in the developing countries. Progress and affluence in the technologically developed countries has been achieved at the expense of depletion of natural resources and deterioration of the environment at the global level. Each of the 3 important factors responsible for environmental pollution--population growth, increase in affluence, and industrialization--are reviewed. There are direct and indirect effects of population growth on the environment. Other things being equal, the greater the population, the more significant are the changes brought about in the environment. More people increases demands on food, energy, housing, clothing, and transportation, all of which lead to environmental pollution. Poor quality or insufficiency of food supply, sanitation, water supply, housing, employment, and health and other services are common problems in countries with high rates of population increase. Problems of domestic sewage and solid waste disposal are directly related to the number of people. Economic growth means more consumption of resources. The effect of affluence can possibly be better understood in the context of the problem of food. With the improved economic status of the peole in many countries, the composition of their diet has been changing. Examining the grain requirements in different countries is a way to understand the effect of increased affluence on the demand for food. During 1969-70 the high income countries with 30% of the world population accounting for 51% of the total consumption of cereals. The higher rate of consumption of cereals in the developed countries is due to indirect utilization. Cereals which can be directly consumed by humans are fed to cattle. The per capita amount of direct and indirect grain consumption continues to increase as per capita income climbs. Developing countries, in their anxiety to

  14. Checking population pressure in India.

    Science.gov (United States)

    Mittal, S P

    1983-01-26

    In India the need for controlling the population explosion is greater than ever before. This is because the 1981 census shows that the rate of population growth is too fast to be matched by the rate of economic development, meaning that whatever gains are made from development projects will be neutralized by the increased demand from the growing population. Against this background, increased awareness has arisen of the need to spare no efforts to contain population growth. In 1961 the target set was to reduce the birthrate to 25/1000 by 1973, but the birthrate was reduced only to 33/1000. The revised target is to reduce the birthrate to 21/1000 by the year 2000. To achieve the target it is necessary to cover at least 60% of the eligibile couples with contraceptive services by 2000 compared to the present level of 20% coverage of eligible couples. The question that arises is whether the present policies and programs are adequate for achieving the target. The people must be motivated, and the environment must be made conducive to greater acceptance of family planning. This cannot be accomplished by the government alone. If community leaders are involved, there is a greater chance of family planning acceptance. It was this realization that was responsible for the formation of the Indian Association of Parliamentarians on Population and Development with a view toward supplementing the efforts at the official level for the acceptance of the concept of the small family and providing the necessary services at the doorsteps of the people. The Association has been successful in creating an environment of political consensus in favor of family planning. Apart from education and motivational campaigns, there are incentives and disincentives. Incentives include monetary compensation to acceptors and motivators. Some opposition exists in relation to disincentives. The feeling exists that the line between compulsion and disincentives is very thin. The following are included

  15. How fast is population ageing in China?

    OpenAIRE

    Yinhua mai; Xiujian Peng; Wei Chen

    2009-01-01

    Using adjusted 2000 population census data, this paper conducts China's population projections to 2050. Three fertility and four mortality scenarios yield 12 sets of results. Despite the below-replacement fertility, China's population will continue growing for many years. However, there are substantial differences among the twelve scenarios. The maximum population could range from less than 1.4 billion to more than 1.6 billion. One of the notable trends is the rapid population ageing. By the ...

  16. Microbial populations in contaminant plumes

    Science.gov (United States)

    Haack, Sheridan K.; Bekins, Barbara A.

    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. La biodégradation efficace des polluants souterrains requiert deux éléments: des populations microbiennes possédant les aptitudes nécessaires à la dégradation, et des conditions géochimiques et hydrologiques souterraines favorables. Des contraintes pratiques sur la conception et l'interprétation des expériences à la fois en microbiologie et en hydrogéologie ont conduit à une connaissance limitée des interactions entre les

  17. Golija: Population development and perspectives

    Directory of Open Access Journals (Sweden)

    Vojković Gordana

    2006-01-01

    Full Text Available The basic research idea was to determine the state and problems in population development of an isolated mountainous region, which has been marked as a potentially developmental and attractive region in the Regional Plan of Serbia, having in mind that it is rich in valuable natural resources. Research was focused just on the protected region of the "Golija" Nature Park, however, wherever it was necessary for better understanding of demographic trends, the wider functional-gravitational region was analyzed, which belongs to the districts of Ivanjica, Kraljevo, Novi Pazar, Raška and Sjenica in the administration sense. It was determined that the following unfavorable (limiting elements of demographic development are characteristic for the region of Golija: constant decrease of population, which is present in practically all settlements, intensive population emigration which has been decreasing in the last ten years or so due to the decrease in the number of potential emigrants; fluctuations in all relevant demographic structures; intensification of the process of demographic ageing which results in continual decrease of natural growth and disruption of all basic functional contingents of population which will certainly negatively affect future reproduction and population replacement. If such a negative state is taken into consideration then the question of demographic and thus developmental perspectives of this mountainous region is justifiably imposed and brought into question. The second part of the paper indicates to the demographic perspectives of the Golija region. According to the first estimation variant, which proceeds from the assumption on the continuation of the basic tendencies in demographic development so far, the number of inhabitants of Golija would be halved by the year 2030. In the second estimation variant, which proceeds from the assumption that in the near future some more serious changes in the functional structure of this

  18. Culture´Contribution to Democracy: Culture, nationalisme and Populism

    DEFF Research Database (Denmark)

    Duelund, Peter

    2018-01-01

    Developments on culture, populism and democracy in Europe. Reasons to populism?   Is populism a new phenomenon? Populism as catch-all label? Common indicators of populism How to deal with populists? Proposal to a comparative COE study on populism......Developments on culture, populism and democracy in Europe. Reasons to populism?   Is populism a new phenomenon? Populism as catch-all label? Common indicators of populism How to deal with populists? Proposal to a comparative COE study on populism...

  19. Population genetics and cryptic species

    International Nuclear Information System (INIS)

    McPheron, Bruce A.

    2000-01-01

    Does the definition of a species matter for pest management purposes? Taxonomists provide us with tools - usually morphological characters - to identify a group of organisms that we call a species. The implication of this identification is that all of the individuals that fit the provided description are members of the species in question. The taxonomists have considered the range of variation among individuals in defining the species, but this variation is often forgotten when we take the concept of species to the level of management. Just as there is morphological variation among individuals, there is also variation in practically any character we might imagine, which has implications for the short and long term success of our management tactics. The rich literature on insecticide resistance should be a constant reminder of the fact that the pressure on pest survival and reproduction applied by our management approaches frequently leads to evolutionary changes within the pest species. The degree of variation within a particular species is a defining characteristic of that species. This level of variability may have very important implications for successful management, so it is very important to measure variation and, whenever possible, the genetic basis of that variation, in a target species. Population genetic approaches can provide evidence of genetic structure (or lack thereof) among populations of a species. These types of data can be used to discuss the movement of pest populations on a local or global scale. In other cases, we may have a complex of species that share some, but not all, characteristics. Species complexes that share morphological characters (i.e., cannot be easily distinguished) but not biological characters are referred to as sibling or cryptic species

  20. Populations of concern: Chapter 9

    Science.gov (United States)

    Gamble, Janet; Balbus, John; Berger, Martha; Bouye, Karen; Campbell, Vince; Chief, Karletta; Conlon, K.; Crimmins, Allison; Flanagan, Barry; Gonzalez-Maddux, C.; Hallisey, E.; Hutchins, S.; Jantarasami, L.; Khoury, S.; Kiefer, M.; Kolling, J.; Lynn, K.; Manangan, A.; McDonald, M.; Morello-Frosch, R.; Hiza, Margaret; Sheffield, P.; Thigpen Tart, K.; Watson, J.; Whyte, K.P.; Wolkin, A.F.

    2016-01-01

    Climate change is already causing, and is expected to continue to cause, a range of health impacts that vary across different population groups in the United States. The vulnerability of any given group is a function of its sensitivity to climate change related health risks, its exposure to those risks, and its capacity for responding to or coping with climate variability and change. Vulnerable groups of people, described here as populations of concern, include those with low income, some communities of color, immigrant groups (including those with limited English proficiency), Indigenous peoples, children and pregnant women, older adults, vulnerable occupational groups, persons with disabilities, and persons with preexisting or chronic medical conditions. Planners and public health officials, politicians and physicians, scientists and social service providers are tasked with understanding and responding to the health impacts of climate change. Collectively, their characterization of vulnerability should consider how populations of concern experience disproportionate, multiple, and complex risks to their health and well-being in response to climate change. Some groups face a number of stressors related to both climate and non-climate factors. For example, people living in impoverished urban or isolated rural areas, floodplains, coastlines, and other at-risk locations are more vulnerable not only to extreme weather and persistent climate change but also to social and economic stressors. Many of these stressors can occur simultaneously or consecutively. Over time, this “accumulation” of multiple, complex stressors is expected to become more evident1 as climate impacts interact with stressors associated with existing mental and physical health conditions and with other socioeconomic and demographic factors.

  1. World population problems: an overview.

    Science.gov (United States)

    Potts, M

    1989-06-01

    Over 50% of the world's population is below the age of marriage, which indicates rapid expansion of the population into the next century. The developing countries produce 85% of the births, 95% of infant deaths, and in some, 99% of maternal deaths. Acquired immunodeficiency syndrome (AIDS) will slow population growth but will not reverse the trend. Family planning programs have worked as evidenced by declining fertility rates. In the US there was a total fertility rate decline of 6 to 3.5 in 58 years. In Sri Lanka the same change took 30 years, in Thailand 15 years and in China 7 years. Family planning programs that are successful provide condoms cheaply, provide community distribution of pills, offer sterilization to male and females, and promote long periods of lactation. Abortion rates are often higher in countries where they are illegal and family planning is usually not offered. Social marketing and voluntary sterilization are the most cost effective birth control methods as proven in less developed countries. Management is the vital factor in more cost effective family planning programs. In sub-Saharan Africa and India there will be a need to subsidize contraceptives well into the next century. If the world is to be serious about family planning, many industrialized countries will have to contribute resources. Private sector involvement needs to be emphasized more in developing countries. Resources are low because of a lack of political will caused by a lack of understanding of the facts of demographic growth. There have been estimates that it will take $7.5 billion to satisfy the developing countries' birth control needs: there is only $1.5 billion being spent now. Many countries are not providing family planning quickly enough and may be forced to give up the freedom to choose family size. The choice of policy makers now is to increase the resources for contraceptive research, or to settle with abortion and sterilization as backup to inadequate methods.

  2. Population Genomics of Paramecium Species.

    Science.gov (United States)

    Johri, Parul; Krenek, Sascha; Marinov, Georgi K; Doak, Thomas G; Berendonk, Thomas U; Lynch, Michael

    2017-05-01

    Population-genomic analyses are essential to understanding factors shaping genomic variation and lineage-specific sequence constraints. The dearth of such analyses for unicellular eukaryotes prompted us to assess genomic variation in Paramecium, one of the most well-studied ciliate genera. The Paramecium aurelia complex consists of ∼15 morphologically indistinguishable species that diverged subsequent to two rounds of whole-genome duplications (WGDs, as long as 320 MYA) and possess extremely streamlined genomes. We examine patterns of both nuclear and mitochondrial polymorphism, by sequencing whole genomes of 10-13 worldwide isolates of each of three species belonging to the P. aurelia complex: P. tetraurelia, P. biaurelia, P. sexaurelia, as well as two outgroup species that do not share the WGDs: P. caudatum and P. multimicronucleatum. An apparent absence of global geographic population structure suggests continuous or recent dispersal of Paramecium over long distances. Intergenic regions are highly constrained relative to coding sequences, especially in P. caudatum and P. multimicronucleatum that have shorter intergenic distances. Sequence diversity and divergence are reduced up to ∼100-150 bp both upstream and downstream of genes, suggesting strong constraints imposed by the presence of densely packed regulatory modules. In addition, comparison of sequence variation at non-synonymous and synonymous sites suggests similar recent selective pressures on paralogs within and orthologs across the deeply diverging species. This study presents the first genome-wide population-genomic analysis in ciliates and provides a valuable resource for future studies in evolutionary and functional genetics in Paramecium. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. Ageing populations: the challenges ahead

    DEFF Research Database (Denmark)

    Christensen, Kaare; Doblhammer, Gabriele; Rau, Roland

    2009-01-01

    If the pace of increase in life expectancy in developed countries over the past two centuries continues through the 21st century, most babies born since 2000 in France, Germany, Italy, the UK, the USA, Canada, Japan, and other countries with long life expectancies will celebrate their 100th...... birthdays. Although trends differ between countries, populations of nearly all such countries are ageing as a result of low fertility, low immigration, and long lives. A key question is: are increases in life expectancy accompanied by a concurrent postponement of functional limitations and disability...

  4. Measuring happiness in large population

    Science.gov (United States)

    Wenas, Annabelle; Sjahputri, Smita; Takwin, Bagus; Primaldhi, Alfindra; Muhamad, Roby

    2016-01-01

    The ability to know emotional states for large number of people is important, for example, to ensure the effectiveness of public policies. In this study, we propose a measure of happiness that can be used in large scale population that is based on the analysis of Indonesian language lexicons. Here, we incorporate human assessment of Indonesian words, then quantify happiness on large-scale of texts gathered from twitter conversations. We used two psychological constructs to measure happiness: valence and arousal. We found that Indonesian words have tendency towards positive emotions. We also identified several happiness patterns during days of the week, hours of the day, and selected conversation topics.

  5. SOCIAL EXCLUSION AND VULNERABLE POPULATIONS

    Directory of Open Access Journals (Sweden)

    ROXANA PLEŞA

    2013-12-01

    Full Text Available In the last half of the century, significant technological, economic, demographic, political, and ideological changes took place; advanced democracies went to a process of deep economic restructurings. While universal social policies still provide for protection against predictable risks of a life cycle, individual carrier models and welfare standardization can no longer be assumed. There are more and more people suffering from insecurity, or lacking protection of any kind. Excluded populations are therefore more affected than any other categories of social actors and their poverty is more obvious; in a certain sense, it is less “natural” than it has ever been.

  6. Nonlinear dynamics of interacting populations

    CERN Document Server

    Bazykin, Alexander D

    1998-01-01

    This book contains a systematic study of ecological communities of two or three interacting populations. Starting from the Lotka-Volterra system, various regulating factors are considered, such as rates of birth and death, predation and competition. The different factors can have a stabilizing or a destabilizing effect on the community, and their interplay leads to increasingly complicated behavior. Studying and understanding this path to greater dynamical complexity of ecological systems constitutes the backbone of this book. On the mathematical side, the tool of choice is the qualitative the

  7. Bacterial computing with engineered populations.

    Science.gov (United States)

    Amos, Martyn; Axmann, Ilka Maria; Blüthgen, Nils; de la Cruz, Fernando; Jaramillo, Alfonso; Rodriguez-Paton, Alfonso; Simmel, Friedrich

    2015-07-28

    We describe strategies for the construction of bacterial computing platforms by describing a number of results from the recently completed bacterial computing with engineered populations project. In general, the implementation of such systems requires a framework containing various components such as intracellular circuits, single cell input/output and cell-cell interfacing, as well as extensive analysis. In this overview paper, we describe our approach to each of these, and suggest possible areas for future research. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  8. A Tale of Two Populations

    Science.gov (United States)

    2005-03-01

    VLT FLAMES Finds Hints of Helium-Richest Stars Ever Seen Summary On the basis of stellar spectra totalling more than 200 hours of effective exposure time with the 8.2-m VLT Kueyen telescope at Paranal (Chile), a team of astronomers [1] has made a surprising discovery about the stars in the giant southern globular cluster Omega Centauri. It has been known for some time that, contrary to other clusters of this type, this stellar cluster harbours two different populations of stars that still burn hydrogen in their centres. One population, accounting for one quarter of its stars, is bluer than the other. Using the FLAMES multi-object spectrograph that is particularly well suited to this kind of work, the astronomers found that the bluer stars contain more heavy elements than those of the redder population. This was exactly opposite to the expectation and they are led to the conclusion that the bluer stars have an overabundance of the light element helium of more than 50%. They are in fact the most helium rich stars ever found. But why is this so? The team suggests that this puzzle may be explained in the following way. First, a great burst of star formation took place during which all the stars of the red population were produced. As other normal stars, these stars transformed their hydrogen into helium by nuclear burning. Some of them, with masses of 10-12 times the mass of the Sun, soon thereafter exploded as supernovae, thereby enriching the interstellar medium in the globular cluster with helium. Next, the blue population stars formed from this helium-rich medium. This unexpected discovery provides important new insights into the way stars may form in larger stellar systems. PR Photo 08a/05: The Omega Centauri Globular Cluster and the Area Surveyed (DSS and ACS/HST) PR Photo 08b/05: The Double Main Sequence of Omega Centauri PR Photo 08c/05: Average Spectra of the Blue and Red Population Stars (FLAMES + VLT) PR Photo 08d/05: The Supernova Scenario Two Populations

  9. Normal and sublethally irradiated stem and granulocyte progenitor cell regeneration in an in vivo culture system. The cellular response to humoral factors released through the action of cyclophosphamide

    International Nuclear Information System (INIS)

    MacVittie, T.

    1977-01-01

    The in vivo diffusion chamber (DC) method of marrow culture was used to determine if the injection of host mice with cyclophosphamide (CY) caused, through its cytoxic action, the release of a humoral factor(s) capable of initiating stem cell (CFU-s) and granulocyte-macrophage progenitor cell (CFU-c) proliferation. Host mice were injected with CY 1-4 days prior to 800 rad of 60 Co WBI and implantation of DCs containing normal or 400 rad sublethally irradiated (SLI) marrow cells. The greatest proliferative response within CFU-s and CFU-c populations occurred in those mice injected with CY 3 days prior to implant. The marked CFU-s and CFU-c regeneration was initiated during the initial 24 hr of culture in both normal and SLI marrow cells. Thereafter growth rates were approximately the same. SLI marrow, however, showed a greater response to the humoral effects of CY injection than did normal marrow. These data provided evidence that CY induced the release of a diffusible factor(s) capable of accelerating regeneration of normal and sublethally irradiated CFU-s and CFU-c, the magnitude of which was dependent upon the time elapsed between CY injected and implantation of DCs. The marked proliferative response of the SLI stem and progenitor cells to the humoral stimulation may be indicative of the heterogeneity of both CFU-s and CFU-c populations surviving sublethal radiation exposure. The target cells may have possessed a differential sensitivity to the factor(s) initiating cell proliferation

  10. Optimal Population and Exhaustible Resource Constraints.

    Science.gov (United States)

    Lawson, Nicholas; Spears, Dean

    2018-01-01

    A large literature considers the optimal size and growth rate of the human population, trading off the utility value of additional people with the costs of a larger population. In this literature, an important parameter is the social weight placed on population size; a standard result is that a planner with a larger weight on population chooses larger population levels and growth rates. We demonstrate that this result is conditionally overturned when an exhaustible resource constraint is introduced: if the discount rate is small enough, the optimal population today decreases with the welfare weight on population size. That is, a more total-utilitarian social planner could prefer a smaller population today than a more average-utilitarian social planner. We also present a numerical illustration applied to the case of climate change, where we show that under plausible real-world parameter values, our result matters for the direction and magnitude of optimal population policy.

  11. Who fears and who welcomes population decline?

    Directory of Open Access Journals (Sweden)

    Hendrik P. Van Dalen

    2011-08-01

    Full Text Available European countries are experiencing population decline and the tacit assumption in most analyses is that the decline may have detrimental welfare effects. In this paper we use a survey among the population in the Netherlands to discover whether population decline is always met with fear. A number of results stand out: population size preferences differ by geographic proximity: at a global level the majority of respondents favors a (global population decline, but closer to home one supports a stationary population. Population decline is clearly not always met with fear: 31 percent would like the population to decline at the national level and they generally perceive decline to be accompanied by immaterial welfare gains (improvement environment as well as material welfare losses (tax increases, economic stagnation. In addition to these driving forces it appears that the attitude towards immigrants is a very strong determinant at all geographical levels: immigrants seem to be a stronger fear factor than population decline.

  12. Symbolic trephinations and population structure

    Directory of Open Access Journals (Sweden)

    László Szathmáry

    2006-12-01

    Full Text Available The sample examined consists of 19 skulls with symbolic trephinations and 86 skulls without trepanations dated from the X century. Skulls were all excavated in the Great Hungarian Plain in the Carpathian Basin, which was occupied by the Hungarian conquerors at the end of the IX century. The variations of 12 cranial dimensions of the trephined skulls were investigated and compared to the skulls without trepanations after performing a discriminant analysis. The classification results evince that the variability of non-trephined skulls shows a more homogeneous and a more characteristic picture of their own group than the trephined samples, which corresponds to the notion, formed by archaeological evidence and written historical sources, of a both ethnically and socially differing population of the Hungarian conquerors. According to historical research, a part of the population was of Finno-Ugric origin, while the military leading layer of society can be brought into connection with Turkic ethnic groups. All the same, individuals dug up with rich grave furniture and supposed to belong to this upper stratum of society are primarily characterized by the custom of symbolic trephination, and, as our results demonstrate, craniologically they seem to be more heterogeneous.

  13. Paraguay: population and the economy.

    Science.gov (United States)

    Sanders, T G

    1986-01-01

    Paraguay's political conflicts and development experiences have been accompanied by compensatory population movements; however, economic and population policies of the past are not adequate to address the current economic challenges. The principal structural problem is dependence on international commodity prices. Since late 1984, the international prices for soya and cotton have declined more than 50%; these 2 products account for 83% of official exports. The external debt has grown significantly in the past 5 years and is increasingly difficult to service. A major problem the government faces in servicing the debt and maintaining economic growth is its inability to get control of foreign exchange. Much of Paraguay's external trade is contraband, with the dollars passing into the black market. As a result of the illegal economy, government earnings have been insufficient to cover expenses. Unemployment stands at 12% because of general economic decline, cuts in government expenditure, and the reduction of investment in hydroelectricity. Occupation of new land, the classic solution by the Paraguayan peasantry, is no longer a viable option since all land is now utilized. About 20-25% of Paraguayans live outside the country, expecially in Argentina. In 1986, a commission drafted an Adjustment Plan that recommended a devaluation of the official gurani rate, tax increases, higher tariffs for public services, and incentives to invest in priority areas; however, this plan has not been implemented to date.

  14. Social exclusion in finite populations

    Science.gov (United States)

    Li, Kun; Cong, Rui; Wu, Te; Wang, Long

    2015-04-01

    Social exclusion, keeping free riders from benefit sharing, plays an important role in sustaining cooperation in our world. Here we propose two different exclusion regimes, namely, peer exclusion and pool exclusion, to investigate the evolution of social exclusion in finite populations. In the peer exclusion regime, each excluder expels all the defectors independently, and thus bears the total cost on his own, while in the pool exclusion regime, excluders spontaneously form an institution to carry out rejection of the free riders, and each excluder shares the cost equally. In a public goods game containing only excluders and defectors, it is found that peer excluders outperform pool excluders if the exclusion costs are small, and the situation is converse once the exclusion costs exceed some critical points, which holds true for all the selection intensities and different update rules. Moreover, excluders can dominate the whole population under a suitable parameters range in the presence of second-order free riders (cooperators), showing that exclusion has prominent advantages over common costly punishment. More importantly, our finding indicates that the group exclusion mechanism helps the cooperative union to survive under unfavorable conditions. Our results may give some insights into better understanding the prevalence of such a strategy in the real world and its significance in sustaining cooperation.

  15. Diversity of aquatic bacterial populations

    International Nuclear Information System (INIS)

    Teska, J.D.

    1988-01-01

    A study was designed to evaluate the feasibility of adapting the automated Quantum II for the identification of bacterial fish pathogens. Optimal incubation conditions were determined for each of the species used, and, by using a Chi-square goodness of fit test, it was shown that isolates could be sorted into like-species groups with a Ward's hierarchical cluster analysis technique. In a second study, population profiles, growth kinetics, and transformation kinetics were evaluated for bacteria isolated from 4 aquatic environments located in the southeastern United States. Gradual long-term accumulation of organic acids in the waters of the Okefenokee Swamp, located in southeast Georgia and northeast Florida, has resulted in acidic water ranging from pH 3.5 to 4.5. A study was designed to evaluate the metabolic efficiency of surface-water gram-negative nonfermentative bacteria and ascertain whether aquatic bacterial populations exhibit adaptation to the low pH conditions. Using the computerized AMBIS the uptake and incorporation of 35 S-methionine into bacterial proteins under 5 levels of pH was quantitated for each of the test organisms

  16. Salmonella Populations inside Host Cells

    Directory of Open Access Journals (Sweden)

    Sónia Castanheira

    2017-10-01

    Full Text Available Bacteria of the Salmonella genus cause diseases ranging from gastroenteritis to life-threatening typhoid fever and are among the most successful intracellular pathogens known. After the invasion of the eukaryotic cell, Salmonella exhibits contrasting lifestyles with different replication rates and subcellular locations. Although Salmonella hyper-replicates in the cytosol of certain host cell types, most invading bacteria remain within vacuoles in which the pathogen proliferates at moderate rates or persists in a dormant-like state. Remarkably, these cytosolic and intra-vacuolar intracellular lifestyles are not mutually exclusive and can co-exist in the same infected host cell. The mechanisms that direct the invading bacterium to follow the cytosolic or intra-vacuolar “pathway” remain poorly understood. In vitro studies show predominance of either the cytosolic or the intra-vacuolar population depending on the host cell type invaded by the pathogen. The host and pathogen factors controlling phagosomal membrane integrity and, as consequence, the egress into the cytosol, are intensively investigated. Other aspects of major interest are the host defenses that may affect differentially the cytosolic and intra-vacuolar populations and the strategies used by the pathogen to circumvent these attacks. Here, we summarize current knowledge about these Salmonella intracellular subpopulations and discuss how they emerge during the interaction of this pathogen with the eukaryotic cell.

  17. Mantel test in population genetics.

    Science.gov (United States)

    Diniz-Filho, José Alexandre F; Soares, Thannya N; Lima, Jacqueline S; Dobrovolski, Ricardo; Landeiro, Victor Lemes; de Campos Telles, Mariana Pires; Rangel, Thiago F; Bini, Luis Mauricio

    2013-12-01

    The comparison of genetic divergence or genetic distances, estimated by pairwise FST and related statistics, with geographical distances by Mantel test is one of the most popular approaches to evaluate spatial processes driving population structure. There have been, however, recent criticisms and discussions on the statistical performance of the Mantel test. Simultaneously, alternative frameworks for data analyses are being proposed. Here, we review the Mantel test and its variations, including Mantel correlograms and partial correlations and regressions. For illustrative purposes, we studied spatial genetic divergence among 25 populations of Dipteryx alata ("Baru"), a tree species endemic to the Cerrado, the Brazilian savannas, based on 8 microsatellite loci. We also applied alternative methods to analyze spatial patterns in this dataset, especially a multivariate generalization of Spatial Eigenfunction Analysis based on redundancy analysis. The different approaches resulted in similar estimates of the magnitude of spatial structure in the genetic data. Furthermore, the results were expected based on previous knowledge of the ecological and evolutionary processes underlying genetic variation in this species. Our review shows that a careful application and interpretation of Mantel tests, especially Mantel correlograms, can overcome some potential statistical problems and provide a simple and useful tool for multivariate analysis of spatial patterns of genetic divergence.

  18. Reconstructing Native American population history.

    Science.gov (United States)

    Reich, David; Patterson, Nick; Campbell, Desmond; Tandon, Arti; Mazieres, Stéphane; Ray, Nicolas; Parra, Maria V; Rojas, Winston; Duque, Constanza; Mesa, Natalia; García, Luis F; Triana, Omar; Blair, Silvia; Maestre, Amanda; Dib, Juan C; Bravi, Claudio M; Bailliet, Graciela; Corach, Daniel; Hünemeier, Tábita; Bortolini, Maria Cátira; Salzano, Francisco M; Petzl-Erler, María Luiza; Acuña-Alonzo, Victor; Aguilar-Salinas, Carlos; Canizales-Quinteros, Samuel; Tusié-Luna, Teresa; Riba, Laura; Rodríguez-Cruz, Maricela; Lopez-Alarcón, Mardia; Coral-Vazquez, Ramón; Canto-Cetina, Thelma; Silva-Zolezzi, Irma; Fernandez-Lopez, Juan Carlos; Contreras, Alejandra V; Jimenez-Sanchez, Gerardo; Gómez-Vázquez, Maria José; Molina, Julio; Carracedo, Angel; Salas, Antonio; Gallo, Carla; Poletti, Giovanni; Witonsky, David B; Alkorta-Aranburu, Gorka; Sukernik, Rem I; Osipova, Ludmila; Fedorova, Sardana A; Vasquez, René; Villena, Mercedes; Moreau, Claudia; Barrantes, Ramiro; Pauls, David; Excoffier, Laurent; Bedoya, Gabriel; Rothhammer, Francisco; Dugoujon, Jean-Michel; Larrouy, Georges; Klitz, William; Labuda, Damian; Kidd, Judith; Kidd, Kenneth; Di Rienzo, Anna; Freimer, Nelson B; Price, Alkes L; Ruiz-Linares, Andrés

    2012-08-16

    The peopling of the Americas has been the subject of extensive genetic, archaeological and linguistic research; however, central questions remain unresolved. One contentious issue is whether the settlement occurred by means of a single migration or multiple streams of migration from Siberia. The pattern of dispersals within the Americas is also poorly understood. To address these questions at a higher resolution than was previously possible, we assembled data from 52 Native American and 17 Siberian groups genotyped at 364,470 single nucleotide polymorphisms. Here we show that Native Americans descend from at least three streams of Asian gene flow. Most descend entirely from a single ancestral population that we call 'First American'. However, speakers of Eskimo-Aleut languages from the Arctic inherit almost half their ancestry from a second stream of Asian gene flow, and the Na-Dene-speaking Chipewyan from Canada inherit roughly one-tenth of their ancestry from a third stream. We show that the initial peopling followed a southward expansion facilitated by the coast, with sequential population splits and little gene flow after divergence, especially in South America. A major exception is in Chibchan speakers on both sides of the Panama isthmus, who have ancestry from both North and South America.

  19. Reconstructing Native American Population History

    Science.gov (United States)

    Reich, David; Patterson, Nick; Campbell, Desmond; Tandon, Arti; Mazieres, Stéphane; Ray, Nicolas; Parra, Maria V.; Rojas, Winston; Duque, Constanza; Mesa, Natalia; García, Luis F.; Triana, Omar; Blair, Silvia; Maestre, Amanda; Dib, Juan C.; Bravi, Claudio M.; Bailliet, Graciela; Corach, Daniel; Hünemeier, Tábita; Bortolini, Maria-Cátira; Salzano, Francisco M.; Petzl-Erler, María Luiza; Acuña-Alonzo, Victor; Aguilar-Salinas, Carlos; Canizales-Quinteros, Samuel; Tusié-Luna, Teresa; Riba, Laura; Rodríguez-Cruz, Maricela; Lopez-Alarcón, Mardia; Coral-Vazquez, Ramón; Canto-Cetina, Thelma; Silva-Zolezzi, Irma; Fernandez-Lopez, Juan Carlos; Contreras, Alejandra V.; Jimenez-Sanchez, Gerardo; Gómez-Vázquez, María José; Molina, Julio; Carracedo, Ángel; Salas, Antonio; Gallo, Carla; Poletti, Giovanni; Witonsky, David B.; Alkorta-Aranburu, Gorka; Sukernik, Rem I.; Osipova, Ludmila; Fedorova, Sardana; Vasquez, René; Villena, Mercedes; Moreau, Claudia; Barrantes, Ramiro; Pauls, David; Excoffier, Laurent; Bedoya, Gabriel; Rothhammer, Francisco; Dugoujon, Jean Michel; Larrouy, Georges; Klitz, William; Labuda, Damian; Kidd, Judith; Kidd, Kenneth; Rienzo, Anna Di; Freimer, Nelson B.; Price, Alkes L.; Ruiz-Linares, Andrés

    2013-01-01

    The peopling of the Americas has been the subject of extensive genetic, archaeological and linguistic research; however, central questions remain unresolved1–5. One contentious issue is whether the settlement occurred via a single6–8 or multiple streams of migration from Siberia9–15. The pattern of dispersals within the Americas is also poorly understood. To address these questions at higher resolution than was previously possible, we assembled data from 52 Native American and 17 Siberian groups genotyped at 364,470 single nucleotide polymorphisms. We show that Native Americans descend from at least three streams of Asian gene flow. Most descend entirely from a single ancestral population that we call “First American”. However, speakers of Eskimo-Aleut languages from the Arctic inherit almost half their ancestry from a second stream of Asian gene flow, and the Na-Dene-speaking Chipewyan from Canada inherit roughly one-tenth of their ancestry from a third stream. We show that the initial peopling followed a southward expansion facilitated by the coast, with sequential population splits and little gene flow after divergence, especially in South America. A major exception is in Chibchan-speakers on both sides of the Panama Isthmus, who have ancestry from both North and South America. PMID:22801491

  20. Population explosion and population control programmes in Bangladesh: an overview.

    Science.gov (United States)

    Rahman, A S; Nazneen, D R

    1992-01-01

    "The authors discuss in detail efforts made by [the] Bangladesh Government to control its population through planned efforts since 1953. Covering persistent setbacks and reasons thereof in governmental efforts, the authors highlight shifts in policies and strategy.... The [government family planning] programme provides a wide range of contraceptive choice to eligible couples in a manner as acceptable and convenient as possible to the client. The programme is totally voluntary and the government is firmly opposed to coercion or pressure on couples to accept contraception. As a strategy, the programme has integrated health and [family planning] while various ministries have attempted to encourage the acceptance of low-fertility behaviour through socio-economic incentives and educational motivation programmes." excerpt

  1. Population change and educational development.

    Science.gov (United States)

    Jayasuriya, J E

    1982-06-01

    The 4 principal conditions of a stable society are: 1) minimum disruption of ecological processes, 2) maximum conservation of material and energy or an economy of stock rather than flow, 3) a population in which recruitment equals loss, and 4) a social system in which individuals can enjoy rather than be restricted by the 1st 3 conditions. In 1960 the developing countries set goals relating to education including the achievement of universal primary education, the eradication of illiteracy, and the provision of secondary and tertiary education to meet manpower needs. The countries with the highest enrollment ratios in 1980 were Korea, 100%, Singapore, 100%, Malaysia, 94%, Philippines 80.6%, Thailand, 77.8%, and Iran 75.5%. Eradication of illiteracy has not been reached since by 1990 Afghanistan, India, Nepal, and Pakistan will have illiteracy rates of over 50% and as a result of increases in the absolute number of illiterates over the period of 1970-90 in Afghanistan, Bangladesh, India, Nepal, and Pakistan, the number of illiterates in the developing countries of Asia will increase from 339.1 million in 1970 to 425.6 million in 1990. The females and rural population are especially disadvantaged groups in terms of education; 98.4% of rural females are illiterate as compared to 63.8% of urban males and in Iran 91.7% of rural females compared with 31.3% of urban males are illiterate. One reason for shortfalls in the achievement of educational goals is rapid population growth, especially of school-age groups; for instance the total population aged 6-11 in Indonesia increased by 89.3%. In a study on the Philippines conducted in 1975 it was found that, for the series of high projections, the schedule of age-specific fertility rates observed for 1968-72 resulting in a total fertility rate of 5.89 would remain constant throughout the projection period, the death rate would decline by 4.8 points, international migration would remain negligible; for the low projections

  2. Gridded Population of the World, Version 4 (GPWv4): Administrative Unit Center Points with Population Estimates

    Data.gov (United States)

    National Aeronautics and Space Administration — Gridded Population of the World, Version 4 (GPWv4) Administrative Unit Center Points with Population Estimates consists of UN-adjusted estimates of human population...

  3. Gridded Population of the World, Version 4 (GPWv4): Population Density

    Data.gov (United States)

    National Aeronautics and Space Administration — Gridded Population of the World, Version 4 (GPWv4) Population Density consists of estimates of human population density based on counts consistent with national...

  4. Gridded Population of the World, Version 4 (GPWv4): Population Density, Revision 10

    Data.gov (United States)

    National Aeronautics and Space Administration — Gridded Population of the World, Version 4 (GPWv4) Population Density, Revision 10 consists of estimates of human population density (number of persons per square...

  5. Gridded Population of the World, Version 4 (GPWv4): Population Count, Revision 10

    Data.gov (United States)

    National Aeronautics and Space Administration — Gridded Population of the World, Version 4 (GPWv4) Population Count, Revision 10 consists of estimates of human population (number of persons per pixel), consistent...

  6. Population momentum across vertebrate life histories

    Science.gov (United States)

    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.

  7. Heterotrophic bacterial populations in tropical sandy beaches

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, S.; LokaBharathi, P.A.

    Distribution pattern of heterotrophic bacterial flora of three sandy beaches of the west coast of India was studied. The population in these beaches was microbiologically different. Population peaks of halotolerant and limnotolerant forms were...

  8. Measuring populations to improve vaccination coverage

    Science.gov (United States)

    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. Trismus in the paediatric population.

    Science.gov (United States)

    Shires, Peter M; Chow, Gabriel

    2015-04-01

    Trismus is a rare presentation affecting neonates, children, and adults. In newborns there are serious implications, with potential to affect feeding, cause airway problems, and make intubation difficult. Causes of trismus seen in the paediatric patient are discussed in this review article; they are divided into intra- and extra-articular types. The extra-articular group consists of congenital and acquired disorders. The acquired group includes infective causes such as tetanus, iatrogenic causes related to drugs, cancer or dental treatment, and trauma causing articulation difficulty or triggering a rare type of bone growth in myositis ossificans. Changes in the mouth resulting from oral submucous fibrosis can undergo malignant transformation. This review aims to raise awareness of potential causes of trismus in paediatric populations, helping clinicians identify the underlying pathology so appropriate strategies for treatment be applied, with the ultimate aim of improving long-term outlook and quality of life for affected children. © 2014 Mac Keith Press.

  10. Raltegravir use in special populations.

    Science.gov (United States)

    Johnson, Margaret

    2009-11-24

    Raltegravir, the first approved integrase inhibitor, has been shown to be virologically effective in Phase II and Phase III clinical trials in both treatment naive and triple class resistant patients. It also has an excellent tolerability profile and lacks significant drug-drug interactions making it an important drug in the treatment of a number of special patient populations. In this review its use in patients undergoing solid organ and bone marrow transplantation and patients receiving cancer chemotherapy, will be discussed. In addition other indications including patients with metabolic complications of existing antiretroviral drugs as well as patients with side effects on current HAART regimens. Other groups of patients where raltegravir may play an important role are patients with renal disease and tuberculosis. Finally, although not licensed for use in pregnancy, raltegravir may need to be considered in some pregnant women with antiretroviral resistance or tolerability issues with current HAART regimens.

  11. Raltegravir use in special populations

    Directory of Open Access Journals (Sweden)

    Johnson Margaret

    2009-11-01

    Full Text Available Abstract Raltegravir, the first approved integrase inhibitor, has been shown to be virologically effective in Phase II and Phase III clinical trials in both treatment naïve and triple class resistant patients. It also has an excellent tolerability profile and lacks significant drug-drug interactions making it an important drug in the treatment of a number of special patient populations. In this review its use in patients undergoing solid organ and bone marrow transplantation and patients receiving cancer chemotherapy, will be discussed. In addition other indications including patients with metabolic complications of existing antiretroviral drugs as well as patients with side effects on current HAART regimens. Other groups of patients where raltegravir may play an important role are patients with renal disease and tuberculosis. Finally, although not licensed for use in pregnancy, raltegravir may need to be considered in some pregnant women with antiretroviral resistance or tolerability issues with current HAART regimens.

  12. Population dynamics in vasopressin cells.

    Science.gov (United States)

    Leng, Gareth; Brown, Colin; Sabatier, Nancy; Scott, Victoria

    2008-01-01

    Most neurons sense and code change, and when presented with a constant stimulus they adapt, so as to be able to detect a fresh change. However, for some things it is important to know their absolute level; to encode such information, neurons must sustain their response to an unchanging stimulus while remaining able to respond to a change in that stimulus. One system that encodes the absolute level of a stimulus is the vasopressin system, which generates a hormonal signal that is proportional to plasma osmolality. Vasopressin cells sense plasma osmolality and secrete appropriate levels of vasopressin from the neurohypophysis as needed to control water excretion; this requires sustained secretion under basal conditions and the ability to increase (or decrease) secretion should plasma osmolality change. Here we explore the mechanisms that enable vasopressin cells to fulfill this function, and consider how coordination between the cells might distribute the secretory load across the population of vasopressin cells. 2008 S. Karger AG, Basel.

  13. [Genetic structure of natural populations

    International Nuclear Information System (INIS)

    1988-01-01

    Our efforts in the first eight months were concentrated in obtaining a genomic clone of the copper-zinc superoxide dismutase (SOD) in Drosophila melanogaster and other Drosophila species. This we have now successfully accomplished. We seek to understand the role of SOD in radioresistance; how genetic variation in this enzyme is maintained in populations; and relevant aspects of its evolution that may contribute to these goals as well as to an understanding of molecular evolution in general. To accomplish these goals we are undertaking the following experiments: cloning and sequencing of (at least) one F allele, one S allele, and the null allele for SOD; cloning and sequencing SOD from species related to D. melanogaster; and cloning and sequencing the SOD gene from several independently sampled S and F alleles in D. melanogaster. We are also preparing to test the radioprotective effects of SOD. 67 refs

  14. Quantitative variation in natural populations

    International Nuclear Information System (INIS)

    Parsons, P.A.

    1975-01-01

    Quantitative variation is considered in natural populations using Drosophila as the example. A knowledge of such variation enables its rapid exploitation in directional selection experiments as shown for scutellar chaeta number. Where evidence has been obtained, genetic architectures are in qualitative agreement with Mather's concept of balance for traits under stabilizing selection. Additive genetic control is found for acute environmental stresses, but not for less acute stresses as shown by exposure to 60 Co-γ rays. D. simulans probably has a narrower ecological niche than its sibling species D. melanogaster associated with lower genetic heterogeneity. One specific environmental stress to which D. simulans is sensitive in nature is ethyl alcohol as shown by winery data. (U.S.)

  15. Population Dynamics and Air Pollution

    DEFF Research Database (Denmark)

    Flachs, Esben Meulengracht; Sørensen, Jan; Bønløkke, Jacob

    2013-01-01

    Objective. To explore how three different assumptions on demographics affect the health impact of Danish emitted air pollution in Denmark from 2005 to 2030, with health impact modeled from 2005 to 2050. Methods. Modeled air pollution from Danish sources was used as exposure in a newly developed......) a static year 2005 population, (2) morbidity and mortality fixed at the year 2005 level, or (3) an expected development. Results. The health impact of air pollution was estimated at 672,000, 290,000, and 280,000 lost life years depending on demographic assumptions and the corresponding social costs at 430.......4 M€, 317.5 M€, and 261.6 M€ through the modeled years 2005–2050. Conclusion. The modeled health impact of air pollution differed widely with the demographic assumptions, and thus demographics and assumptions on demographics played a key role in making health impact assessments on air pollution....

  16. Population commission discusses international migration.

    Science.gov (United States)

    1997-01-01

    At the 30th session of the Commission on Population and Development during February 24-28, 1997, international migration was the main topic, with special linkages between migration and development and on gender issues and the family. New and emerging issues were also considered. Members stressed the need for more reliable data on migration, the direction of migrants flows, and the characteristics of migrants. The Commission requested a task force on basic social services to hold a technical symposium of experts on international migration in 1998. Its chair, Dr. Nafis Sadik, said that migration issues should based on the reality of choice not on coercive measures or quotas. Almost half of the migrants globally are women. The Commission was given a new impetus by the International Conference on Population and Development held at Cairo in 1994. Migration pressures intensified in the second half of the 1980s and in the early 1990s, creating areas of concern: the negative impact of short-term migration on working conditions in host countries; migration pressures emanating from climatic change; the protection of migrant women and their children; the right of receiving countries to regulate access to their territory; the adverse consequences of forced migration; the situation of persons whose asylum claims have been rejected; the trafficking in women and children, prostitution and coercive adoption; and the sudden and massive arrival of refugees in need of international protection. The 1998 session of the Commission will feature the theme of health and mortality, with special emphasis on the linkages between health and development and on gender and age.

  17. Population Pharmacokinetics of Intranasal Scopolamine

    Science.gov (United States)

    Wu, L.; Chow, D. S. L.; Putcha, L.

    2013-01-01

    Introduction: An intranasal gel dosage formulation of scopolamine (INSCOP) was developed for the treatment of Space Motion Sickness (SMS).The bioavailability and pharmacokinetics (PK) was evaluated using data collected in Phase II IND protocols. We reported earlier statistically significant gender differences in PK parameters of INSCOP at a dose level of 0.4 mg. To identify covariates that influence PK parameters of INSCOP, we examined population covariates of INSCOP PK model for 0.4 mg dose. Methods: Plasma scopolamine concentrations versus time data were collected from 20 normal healthy human subjects (11 male/9 female) after a 0.4 mg dose. Phoenix NLME was employed for PK analysis of these data using gender, body weight and age as covariates for model selection. Model selection was based on a likelihood ratio test on the difference of criteria (-2LL). Statistical significance for base model building and individual covariate analysis was set at P less than 0.05{delta(-2LL)=3.84}. Results: A one-compartment pharmacokinetic model with first-order elimination best described INSCOP concentration ]time profiles. Inclusion of gender, body weight and age as covariates individually significantly reduced -2LL by the cut-off value of 3.84(P less than 0.05) when tested against the base model. After the forward stepwise selection and backward elimination steps, gender was selected to add to the final model which had significant influence on absorption rate constant (ka) and the volume of distribution (V) of INSCOP. Conclusion: A population pharmacokinetic model for INSCOP has been identified and gender was a significant contributing covariate for the final model. The volume of distribution and Ka were significantly higher in males than in females which confirm gender-dependent pharmacokinetics of scopolamine after administration of a 0.4 mg dose.

  18. Psoriasis in the pediatric population

    International Nuclear Information System (INIS)

    Vindas Calderon, Wendy

    2013-01-01

    A scientific and updated bibliographic review is realized for handling and care of a pediatric patient with psoriasis disease. Health personnel related with this pathology must to know the different perspectives and angles of psoriasis, as well as clinical criteria, therapeutic and emotional in the treatment of patients. The incidence of psoriasis is recognized globally. Ethnic groups have developed with most frequently this disorder. The different clinical faces of psoriasis are studied. The morphological and topographical manifestations have presented a variety very similar to that of adults, and have made for the doctor difficult to make the diagnostic. Clinical studies that were realized in the last years, have reported etiological and pathogenic evidence, both genetic and immunological of this illness. Children with psoriasis usually have presented a mild illness, where psoriasis type plaque has been the predominant variant. Psoriasis in the population has required a special attention in triggers or aggravating factors of this disease such as infections, exposure to snuff, obesity, stress and interactions with other drugs. The discovery and use of new drugs have led to different etiological factors for the handling of psoriasis; so it is important to know the function, availability and adverse effects that can to cause new therapies. Treatments must to include the provision of a safe and effective therapy for the maintenance for free long periods of lesions, reducing the severity of the disease, and inhibiting structural damage of joints. The topical treatment has been the therapy of first choice in mild psoriasis and localized. An interrogatory is recommended to decide objectively a systemic treatment, because the infant population has been a sensitive group of possible adverse effects. Methotrexate has been the treatment of choice for psoriasis related to arthropathy both adults and children. Phototherapy, including UVB, PUVA light and excimer laser is

  19. The problem of the population dose

    International Nuclear Information System (INIS)

    Belyaev, V.A.

    1976-08-01

    This report investigates methods of calculating the population dose due to emissions from nuclear reactors. The exposure of the local population is considered as well as the exposure of the population of the remote area where food produced near the reactor site is consumed. Units of measurement for the population dose are discussed. A concrete example is given for calculating the contribution of isotopes of radioactive noble gases, 131 I and 137 Cs. (orig.) [de

  20. Colombia merges population affairs with ecology.

    Science.gov (United States)

    1974-01-01

    A National Council on Population and the Environment was established in 1973 in Colombia to advise the government on the integration of population, development, and environmental plans. Most of the emphasis in the decree is on environmental rather than population concerns. The interministerial council recommends social and political policies for incorporation into the national development plan. The Council is charged with encouraging professionalism, research, and population education as well as proposing measures to protect national natural resources.

  1. Georeferenced Population Datasets of Mexico (GEO-MEX): Population Database of Mexico

    Data.gov (United States)

    National Aeronautics and Space Administration — The Population Database of Mexico contains geographically referenced population data for Mexican states, municipalities and localities from the 1990 Mexican...

  2. Africa's Expanding Population: Old Problems, New Policies.

    Science.gov (United States)

    Goliber, Thomas J.

    1989-01-01

    Sub-Saharan Africa faces a historic challenge: to achieve economic and social progress while experiencing extraordinary population growth. With an estimated 1989 population of 512 million, the 42 countries of sub-Saharan Africa have the highest birth and death rates of any major world region. Throughout the region, population has outstripped…

  3. Domestic hygienic legislation concerning population radiation protection

    International Nuclear Information System (INIS)

    Marej, A.N.

    1984-01-01

    Problems and principles of domestic sanitary legislation, concerning population radiation protection, are considered. The legislation envisages preventive measures, directed to contamination preventation of the main environmental objects, it regulates their content in the objects, their human intake and ionizing radiation doses, which might affect population. Existing domestic hygienic guides and safety standards for personnel and population are enumerated and characterized

  4. Leading edge gypsy moth population dynamics

    Science.gov (United States)

    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...

  5. Population Trends and the Implications for Education.

    Science.gov (United States)

    Hauser, Philip M.

    There are three developments which have profoundly affected mans' values, attitudes, social institutions, and behaviorisms. These are the population explosion, the population implosion, and population differentiation. These three developments are interrelated and are affected by accelerating rates of technological and social change. By reason of…

  6. [India: population explosion and demographic transformation].

    Science.gov (United States)

    Domros, M

    1984-02-01

    Recent population trends in India and the policies and programs that have been developed to influence those trends are described. The causes of the rapid population growth that has occurred are first examined, and its consequences are summarized. Consideration is given to regional differences in population distribution and to rural-urban migration. The national family planning program is outlined.

  7. Time to extinction of bird populations

    NARCIS (Netherlands)

    Sæther, B-E.; Engen, S.; Møller, A.P.; Visser, M.E.; Matthysen, E.; Fiedler, W.; Lambrechts, M.M.; Becker, P.H.; Brommer, J.E.; Dickinson, J.; du Feu, C.; Gehlbach, F.R.; Merilä, J.; Rendell, W.; Robertson, R.J.; Thomson, D.L.; Török, J.

    2005-01-01

    The risk of extinction of populations has not previously been empirically related to parameters characterizing their population dynamics. To analyze this relationship, we simulated how the distribution of population dynamical characters changed as a function of time, in both the remaining and the

  8. Dominance and population structure of freshwater crabs ...

    African Journals Online (AJOL)

    ... the availability of refugia for specific/different size classes. Intraspecific aggression, predation and refuge availability are probable strong selection pressures in determining population structures of wild populations of P. perlatus. Keywords: Dominance. linear hierarchy, population structure, refuge availability, rivers, South ...

  9. Biochemical genetic variation between four populations of ...

    African Journals Online (AJOL)

    system) to 0.093 in the Spekboom River population (Limpopo River system). The genetic distance, FST and NEM values, as well as pair-wise contingency c2 analyses indicate a lack of gene flow between populations, as expected for isolated fish. Evidence of foreign genetic material in one population was also observed.

  10. Population Aging and Potential Growth in Asia

    OpenAIRE

    Otsu, Keisuke; Shibayama, Katsuyuki

    2016-01-01

    We study the effects of projected population aging on potential growth in Asian economies over the period 2015–2050. We find that an increase in the share of the population over 64 years of age will significantly lower output growth through decreased labor participation. Population aging can also reduce economic growth through increased labor income taxes and dampened productivity growth.

  11. Population Structure of West Greenland Narwhals

    DEFF Research Database (Denmark)

    Riget, F.; Dietz, R.; Møller, P.

    The hypothesis that different populations of narwhals in the West Greenland area exist has been tested by different biomarkers (metal and organochlorine concentrations, stable isotopes and DNA). Samples of muscle, liver, kidney, blubber and skin tissues of narwhals from West Greenland have been...... isotopes could not support the population structure with two West Greenland populations suggested by the genetic study....

  12. Rates, intrinsic linkages, and multistate population dynamics.

    Science.gov (United States)

    Schoen, Robert

    2017-01-01

    Demographic analyses of multistate populations are commonplace, as are situations where population stocks are known but population flows are not. Still, demographic models for multistate populations with changing rates remain at an early stage of development, limiting dynamic analyses and analytical projections. Here, a new approach, the Intrinsic Linkage-Rate Ratio (IL-RR) model, is presented and explored. The key IL parameter, w , is a simple weight for projecting populations. Using the ultimate state composition implied by the prevailing rates, the IL-RR model provides new relationships that connect multistate populations over time and allow analytical population projections. Parameter w reflects population metabolism and scales the level of the transfer rates. Compositional change is driven by the sequence of implicit stable population compositions. The IL-RR approach also provides a new method for estimating transfer rates within an interval from population numbers at the beginning and end of the interval. The new relationships developed advance the ability of demographers to model multistate populations with changing rates and to relate population stocks and flows.

  13. Thyroid and mammary radiobiology: radiogenic damage to glandular tissue

    International Nuclear Information System (INIS)

    Clifton, K.H.

    1986-01-01

    In this selective survey, emphasis is placed on effects on clonogenic cell populations and their regulation by irradiation. The subject is dealt with under the following headings: glandular structure and functional control, assays of function (radioimmunoassay and enzyme-linked immunoassay methodology), radiogenic thyroid injury; time course and dose, in vivo hormonal assays of target cell populations, the study of clonogen numbers and response to damage, using the thyroid clonogen FD50 transplantation assay and the inhibition of goitrogen-induced thyroid growth assay, the study of radiogenic cancer initiation using the AD50 and FD50 transplantation and assay systems, the relationship between clonogen survival and tissue injury, and the implications for the study of other glands. (UK)

  14. Performance of population size on Knapsack problem

    Directory of Open Access Journals (Sweden)

    David Oyewola

    2016-12-01

    Full Text Available In this paper, an investigation of a performance of population size on the genetic algorithm (GA for a knapsack problem is considered. Population sizes between 10 and 200 chromosomes in the population are tested. In order to obtain meaningful information about the performance of the population size, a considerable number of independent runs of the GA are performed. Accurate model parameters values are obtained in reasonable computational time. Further increase of the population size, does not improve the solution accuracy. Moreover, the computational time is increased significantly.

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

    Science.gov (United States)

    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

  16. Limiting factors in caribou population ecology

    Directory of Open Access Journals (Sweden)

    David R. Klein

    1991-10-01

    Full Text Available Caribou and wild reindeer populations fluctuate over time. On this fact there is general agreement. Factors responsible for population limitation and subsequent declines have been examined within the framework of animal population theory. There is, however, little agreement when factors limiting specific populations are generalized to Rangifer populations over broad geographic regions. Comparative examinations of wild Rangifer populations worldwide discloses that factors that have regulated those populations are highly variable between populations, apparently as a reflection of the differences in environmental variables unique to each population. Examples exist of populations where major regulating factors have been climatic extremes, predation, hunting mortality, food limitation, insects, parasites, disease, interspecific competition, and human developmental impacts or combinations of these factors. This diversity of limiting factors affecting caribou and wild reindeer populations is a reflection of the ecologial complexity of the species, a concept that has often been ignored in past efforts to reach management decisions by extrapolation from the limited localized knowledge available on the species.

  17. Population bottlenecks promote cooperation in bacterial biofilms.

    Directory of Open Access Journals (Sweden)

    Michael A Brockhurst

    2007-07-01

    Full Text Available Population bottlenecks are assumed to play a key role in the maintenance of social traits in microbes. Ecological parameters such as colonisation or disturbances can favour cooperation through causing population bottlenecks that enhance genetic structuring (relatedness. However, the size of the population bottleneck is likely to play a crucial role in determining the success of cooperation. Relatedness is likely to increase with decreasing bottleneck size thus favouring the evolution of cooperation. I used an experimental evolution approach to test this prediction with biofilm formation by the bacterium Pseudomonas fluorescens as the cooperative trait. Replicate populations were exposed to disturbance events every four days under one of six population bottleneck treatments (from 10(3 to 10(8 bacterial cells. In line with predictions, the frequency of evolved cheats within the populations increased with increasing bottleneck size. This result highlights the importance of ecologically mediated population bottlenecks in the maintenance of social traits in microbes.

  18. Cooperation, cheating, and collapse in biological populations

    Science.gov (United States)

    Gore, Jeff

    2014-03-01

    Natural populations can collapse suddenly in response to small changes in environmental conditions, and recovery from such a collapse can be difficult. We have used laboratory microbial ecosystems to directly measure theoretically proposed early warning signals of impending population collapse. Yeast cooperatively break down the sugar sucrose, meaning that below a critical size the population cannot sustain itself. We have demonstrated experimentally that changes in the fluctuations of the population size can serve as an early warning signal that the population is close to 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 confirm this possibility experimentally and find that such social parasitism decreases the resilience of the population.

  19. Population and Economic Growth: A Review Essay

    Directory of Open Access Journals (Sweden)

    Marinko Škare

    2015-08-01

    Full Text Available For centuries, scientists from various scientific fields have been leading lively discussions on the (bidirectional relationship between population growth and economic growth. Particular attention was given to the nature of the population growth variable, i.e. whether it is an endogenous or exogenous variable. The goal of this paper is to position this discussion into a historical, empirical and institutional perspective in order to establish population as an important factor for socio-economic prosperity, mostly measured in terms of economic growth. Regardless of ambiguous empirical conclusions about the influence of population growth on economic growth, the political aspect is crucial. Population effect should not be measured only in terms of population growth, measured by the increase in the number of inhabitants. Population is an endogenous variable which is under the influence of culture, values, political processes and industrial structure.

  20. Keynes on population and economic growth.

    Science.gov (United States)

    Toye, J

    1997-01-01

    This article discusses the evolution of Keynes's thinking on population based on an unpublished paper from 1914, "Is the Problem of Population a Pressing and Important One Now?" The paper is reported to have 39 pages, but in fact there are many missing page numbers. Keynes's "Essays in Biography" (1933) follows the basic structure and much of the verbal detail of the first 16 pages of "Population." Chapter 2 of the "Economic Consequences of the Peace" discusses the key ideas of "Population." The passages in "Population" and Chapter 2 were probably the sources of a fierce controversy in 1923-24 between Keynes and W.H. Beveridge over Keynes' neo-Malthusianism. "Population" was the basis for the three themes that were central to Keynes's writing on population. Keynes's framework shifted from a global perspective in "Population" to a progressively narrower focus in the 1930s on England and Wales. Keynes was stronger in his advocacy of birth control in "Population" compared to later writings. Keynes was concerned about the quality of population but disagreed on the methods of achieving this. Keynes argued that 75% of the world was not subject to Malthusian dynamics, and the other 25% had developed technology to relieve population pressure. "Population" sketches out the rudiments of the welfare implications of the great divide between North and South population growth rates. Keynes assumes that overpopulation in the South will be compensated for by the international market without consideration of income deficits. Keynes argues against pronatalism. The 1933 essay shows Keynes shift away from Malthus as population expert to Malthus as political economist. By 1937, Keynes had recanted and was very aware of the uncertainty of the economy. The author believes that it is unfortunate that this 1913-14 manuscript remains unknown and, if known, misunderstood.

  1. [The development of population policies in Africa].

    Science.gov (United States)

    Sala-diakanda, D M

    1991-12-01

    Influencing demographic dynamics in order to improve the welfare of the population is the fundamental objective of a population policy. The efficacy of a population policy cannot be satisfactorily evaluated without referring to the objectives of the overall development strategy, of which the population policy is only one component. At the time of the 1974 World Population Conference in Bucharest, the positions of the developed and developing countries were polarized. The developing countries were accused of impeding their own socioeconomic development by their high fertility rates and rapid population growth, while the industrialized world was blamed for environmental degradation and exhaustion of nonrenewable resources due to overconsumption by households and industry. Despite the near total disagreement about what constituted the problem, a "World Population Plan of Action" was adopted almost unanimously, indicating agreement at least on the existence of a problem even if ther was no consensus on its content. The Plan affirmed that each nation has a sovereign right to formulate and implement its own population policies, that international cooperation is needed in population matters, and that population policies are components of social and economic development policies and not substitutes for them. Interest in African population dates back to the beginning of the colonial era, when the imperial powers wished to control population movements, estimate the taxable population, and control depopulation due to pathological infertility. Colonial population legislation was somewhat more liberal in English-speaking countries than in those under the sway of France because of the influence of Malthusianism in Great Britain and the movement for birth control that developed there. By the 1984 World Population Conference in Mexico, the governments of African countries had adopted the "Program of Action of Kilimanjaro Concerning the African Population and Autonomous Development

  2. Genetic composition of captive panda population.

    Science.gov (United States)

    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. Suicide risk among homeless population

    Directory of Open Access Journals (Sweden)

    Fran Calvo-García

    2016-06-01

    Full Text Available There exists little scientific production on autolytic behaviour in homeless people, despite the fact that it is one of the groups that is more at risk. The aim of this study is to determine the prevalence of previous attempted suicide and suicide risk and its connection with the main risk factors. In order to do so, central tendency and dispersion measures, correlations, contingence tables, and average comparison tables according to type of variable and normality were used. The Plutchik suicide-risk test was used in order to determine the risk of suicide, and specific tests for the main risk factors analysed. The main results show a 24.7% suicide rate and 45.2% (n = 66 displayed suicide risk. The main predictive factor of the risk of suicide was the daily consumption of alcohol (OR = 1.011, p less than .001, followed by being a woman (OR = 1.381, p = .021. It is necessary to design and apply suicide prevention strategies for this population.

  4. Oxytocin treatment in pediatric populations

    Directory of Open Access Journals (Sweden)

    Adrienne Elise Taylor

    2014-10-01

    Full Text Available The role of endogenous oxytocin as neuromodulator of birth, lactation and social behaviors is well-recognized. Moreover, the use of oxytocin as a facilitator of social and other behaviors is becoming more and more accepted. Many positive effects have been attributed to intranasal oxytocin administration in animals and humans; with current research highlighting encouraging advances in its potential for use in mental health disorders. The new frontier will be investigating the effective use of oxytocin in pediatric populations. Limited animal data is available on this. Large-scale human studies focusing on autism are currently under way, but many other possibilities seem to lie in the future. However, we need to know more about the risks and effects of repeated use on the developing brain and body. This paper will provide an overview of the current understanding of the role of endogenous oxytocin and its related neuropeptide systems in influencing behaviors, in particular attachment, and will review a the literature on the use of intranasal oxytocin in young animals, children (age range birth-12 years and adolescents (age range 13-19 years, b the expected benefits and risks based on the current research, and c the risks of oxytocin in children with severe psychopathology and early life trauma. The paper will conclude with a clinical perspective on these findings

  5. Population avoidance in aimpoint selection

    International Nuclear Information System (INIS)

    Andre, C.G.

    1978-01-01

    In most past studies of the effectiveness of tactical nuclear weapons vs the amount of collateral damage produced (civilian casualties), civilians have been congregated into idealized shaped towns and cities, and criteria for city avoidance were usually formulated in terms relating to a town's population. This treatment was sufficient in those studies where weapon yields were so large that great numbers of civilians were almost always placed at risk. As further studies developed, demonstrating that real progress could be made in reducing the numbers of civilians potentially placed at risk in tactical nuclear warfare situations, the inadequacies of the present treatment became obvious. The need existed for a more detailed description of the distribution of civilians. The method described determines the number of civilians at risk for a weapon under consideration being detonated at a given point and displays a symbol relating to the numbers at risk on a map or a transparency that overlays a 1:50,000 map of the region. Thus, a weapons planner making the selection of aimpoints for inflicting the necessary military damage required has the means to reduce potential civilian casualties by properly choosing the weapon and aimpoints

  6. Adventures in human population biology.

    Science.gov (United States)

    Baker, P T

    1996-01-01

    This article is a memoir of anthropologist Paul Baker's professional life. The introduction notes that the field of anthropology was altered by the impact of World War II when physical anthropologists provided vital information to the military. After the war, the GI bill supported the undergraduate and graduate studies of veterans, including Baker. After describing his academic training at the University of New Mexico and Harvard, Baker details his research training and field work in the desert for the US Climatic Research Laboratory and his work identifying the dead in Japan for the Quartermaster unit. Baker then traces his academic career at the Pennsylvania State University during which he directed two multidisciplinary research efforts for the International Biological Programme, one that sought to understand human adaptability at high altitude in Peru and another that studied migration and modernization in Samoa. Baker's last administrative positions were as staff consultant to the Man and the Biosphere (MAB) program and as chair of the US MAB committee. Baker retired from academic life at age 60 in 1987 and has devoted his time to reading and to helping organize professional associations in anthropology, especially those devoted to furthering internationally organized scientific efforts. Baker concludes this memoir by acknowledging the growth and development of the discipline of human population biology.

  7. 10 CFR 100.11 - Determination of exclusion area, low population zone, and population center distance.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Determination of exclusion area, low population zone, and population center distance. 100.11 Section 100.11 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) REACTOR... and for Testing Reactors § 100.11 Determination of exclusion area, low population zone, and population...

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

    Science.gov (United States)

    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...

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

    Science.gov (United States)

    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...

  10. Population dynamics of species-rich ecosystems: the mixture of matrix population models approach

    DEFF Research Database (Denmark)

    Mortier, Frédéric; Rossi, Vivien; Guillot, Gilles

    2013-01-01

    Matrix population models are widely used to predict population dynamics, but when applied to species-rich ecosystems with many rare species, the small population sample sizes hinder a good fit of species-specific models. This issue can be overcome by assigning species to groups to increase the size...... species with similar population dynamics....

  11. Evolutionary dynamics of cooperation in neutral populations

    Science.gov (United States)

    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.

  12. Between-population outbreeding affects plant defence.

    Directory of Open Access Journals (Sweden)

    Roosa Leimu

    2010-09-01

    Full Text Available Between-population crosses may replenish genetic variation of populations, but may also result in outbreeding depression. Apart from direct effects on plant fitness, these outbreeding effects can also alter plant-herbivore interactions by influencing plant tolerance and resistance to herbivory. We investigated effects of experimental within- and between-population outbreeding on herbivore resistance, tolerance and plant fitness using plants from 13 to 19 Lychnis flos-cuculi populations. We found no evidence for outbreeding depression in resistance reflected by the amount of leaf area consumed. However, herbivore performance was greater when fed on plants from between-population compared to within-population crosses. This can reflect outbreeding depression in resistance and/or outbreeding effects on plant quality for the herbivores. The effects of type of cross on the relationship between herbivore damage and plant fitness varied among populations. This demonstrates how between-population outbreeding effects on tolerance range from outbreeding depression to outbreeding benefits among plant populations. Finally, herbivore damage strengthened the observed outbreeding effects on plant fitness in several populations. These results raise novel considerations on the impact of outbreeding on the joint evolution of resistance and tolerance, and on the evolution of multiple defence strategies.

  13. Conservation genetics of managed ungulate populations

    Science.gov (United States)

    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.

  14. Recovery trends in marine mammal populations.

    Directory of Open Access Journals (Sweden)

    Anna M Magera

    Full Text Available 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

  15. Achieving true sustainability of zoo populations.

    Science.gov (United States)

    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.

  16. Framing the poor: population, elite interests, and the persistence of population control in India

    OpenAIRE

    Schmidt, Ryan Jeffery

    2011-01-01

    The paper examines why, despite a rhetorical shift towards a developmental approach to population issues in India, Malthusian ideology continues to dominate and influence the often heavy-handed efforts of the state to control population growth – largely among vulnerable social groups. An examination of Indian population policies, program implementation, and the population debate represented in the mainstream print media demonstrates that Neo-Malthusian population control measures in India are...

  17. Population structure and genetic diversity of native and invasive populations of Solanum rostratum (Solanaceae.

    Directory of Open Access Journals (Sweden)

    Jiali Zhao

    Full Text Available AIMS: We investigate native and introduced populations of Solanum rostratum, an annual, self-compatible plant that has been introduced around the globe. This study is the first to compare the genetic diversity of Solanum rostratum between native and introduced populations. We aim to (1 determine the level of genetic diversity across the studied regions; (2 explore the likely origins of invasive populations in China; and (3 investigate whether there is the evidence of multiple introductions into China. METHODS: We genotyped 329 individuals at 10 microsatellite loci to determine the levels of genetic diversity and to investigate population structure of native and introduced populations of S. rostratum. We studied five populations in each of three regions across two continents: Mexico, the U.S.A. and China. IMPORTANT FINDINGS: We found the highest genetic diversity among Mexican populations of S. rostratum. Genetic diversity was significantly lower in Chinese and U.S.A. populations, but we found no regional difference in inbreeding coefficients (F IS or population differentiation (F ST. Population structure analyses indicate that Chinese and U.S.A. populations are more closely related to each other than to sampled Mexican populations, revealing that introduced populations in China share an origin with the sampled U.S.A. populations. The distinctiveness between some introduced populations indicates multiple introductions of S. rostratum into China.

  18. [Food and population: study of three countries].

    Science.gov (United States)

    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

  19. Population trends in Malaysia: 1970-2010

    Science.gov (United States)

    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.

  20. bayesPop: Probabilistic Population Projections

    Science.gov (United States)

    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

  1. Statistical Models of Adaptive Immune populations

    Science.gov (United States)

    Sethna, Zachary; Callan, Curtis; Walczak, Aleksandra; Mora, Thierry

    The availability of large (104-106 sequences) datasets of B or T cell populations from a single individual allows reliable fitting of complex statistical models for naïve generation, somatic selection, and hypermutation. It is crucial to utilize a probabilistic/informational approach when modeling these populations. The inferred probability distributions allow for population characterization, calculation of probability distributions of various hidden variables (e.g. number of insertions), as well as statistical properties of the distribution itself (e.g. entropy). In particular, the differences between the T cell populations of embryonic and mature mice will be examined as a case study. Comparing these populations, as well as proposed mixed populations, provides a concrete exercise in model creation, comparison, choice, and validation.

  2. Coexistence of competing stage-structured populations.

    KAUST Repository

    Fujiwara, Masami

    2011-10-05

    This paper analyzes the stability of a coexistence equilibrium point of a model for competition between two stage-structured populations. In this model, for each population, competition for resources may affect any one of the following population parameters: reproduction, juvenile survival, maturation rate, or adult survival. The results show that the competitive strength of a population is affected by (1) the ratio of the population parameter influenced by competition under no resource limitation (maximum compensatory capacity) over the same parameter under a resource limitation due to competition (equilibrium rate) and (2) the ratio of interspecific competition over intraspecific competition; this ratio was previously shown to depend on resource-use overlap. The former ratio, which we define as fitness, can be equalized by adjusting organisms\\' life history strategies, thereby promoting coexistence. We conclude that in addition to niche differentiation among populations, the life history strategies of organisms play an important role in coexistence.

  3. bayesPop: Probabilistic Population Projections

    Directory of Open Access Journals (Sweden)

    Hana Ševčíková

    2016-12-01

    Full Text Available 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.

  4. Population Bottlenecks Promote Cooperation in Bacterial Biofilms

    OpenAIRE

    Brockhurst, Michael A.

    2007-01-01

    Population bottlenecks are assumed to play a key role in the maintenance of social traits in microbes. Ecological parameters such as colonisation or disturbances can favour cooperation through causing population bottlenecks that enhance genetic structuring (relatedness). However, the size of the population bottleneck is likely to play a crucial role in determining the success of cooperation. Relatedness is likely to increase with decreasing bottleneck size thus favouring the evolution of coop...

  5. Population Policy For Karnataka: A Suggested Framework

    OpenAIRE

    P H Rayappa; T V Sekher; M Ramakrishna Reddy

    2000-01-01

    In a vast country like India, with a population of one billion, having high demographic diversity and heterogeneity, and varying levels of socio-economic development among states, a common national population policy might not serve the purpose. An effective population stabilisation programme must be state-specific and address regional disparities, socio-cultural differentials and infrastrucutral problems. This paper discusses the need for a state policy for Karnataka, within the broad framewo...

  6. Population and economic development in Sarawak, Malaysia

    OpenAIRE

    Furuoka, Fumitaka

    2014-01-01

    This paper chooses a Malaysian state in Borneo Island, Sarawak, as the case study to examine the relationship between population growth and economic development. The findings imply that there is no statistically significant long-run relationship, but a causal relationship between population growth and economic development in Sarawak. In other words, the empirical findings indicate that population can have neither positive nor negative impact on economic development. The findings also indicate...

  7. Population Aging: Facts, Challenges, and Responses

    OpenAIRE

    David E. Bloom; Axel Boersch-Supan; Patrick McGee; Atsushi Seike

    2011-01-01

    The world’s population is growing older, leading us into uncharted demographic waters. There will be higher absolute numbers of elderly people, a larger share of elderly, longer healthy life expectancies, and relatively fewer numbers of working-age people. There are alarmist views – both popular and serious – in circulation regarding what these changes might mean for business and economic performance. But the effects of population aging are not straightforward to predict. Population aging doe...

  8. Comparing models of Red Knot population dynamics

    Science.gov (United States)

    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. Intraspecific competition delays recovery of population structure.

    Science.gov (United States)

    Liess, Matthias; Foit, Kaarina

    2010-04-01

    Ecotoxicological field studies have shown that total abundance and biomass often recover shortly after pulsed toxicant stress. In contrast, population structure showed comparatively long-term alterations before reaching pre-treatment conditions. We investigated two mechanisms that may explain the prolonged recovery of population structure: latent toxicant effects on life-history traits on the individual level and competition on the population level. To test these hypotheses we exposed populations of Daphnia magna to a pulse of the pyrethroid Fenvalerate. For several generations the populations were kept at two different degrees of competition: strong competition at carrying capacity and reduced competition maintained by simulated predation. After disturbance due to Fenvalerate exposure, biomass recovered after 14-17 days. In contrast, size structure characterised by a lack of large and dominance of small organisms recovered after 43 days in populations with strong competition. Size structure recovered twice faster in populations with reduced competition. We explain this as follows: due to toxicant induced mortality, food availability and consequently birth rate increased and populations were dominated by small individuals. In populations without predation, these cohorts grew and eventually exerted high intraspecific competition that (i) stopped further growth of juveniles and (ii) increased mortality of adults. These demographic processes were mainly responsible for the prolonged recovery of size structure. In contrast, for populations with predation, the regular harvest of individuals reduced competition. Juveniles developed continuously, allowing a fast recovery of size structure in these dynamic populations. In risk assessment the duration for populations to recover from (toxicant) stress, is crucial for the determination of ecological acceptable effects. We conclude that competition needs to be considered in order to understand and predict recovery of size

  10. Population-based screening versus case detection.

    Directory of Open Access Journals (Sweden)

    Thomas Ravi

    2002-01-01

    Full Text Available India has a large burden of blindness and population-based screening is a strategy commonly employed to detect disease and prevent morbidity. However, not all diseases are amenable to screening. This communication examines the issue of "population-based screening" versus "case detection" in the Indian scenario. Using the example of glaucoma, it demonstrates that given the poor infrastructure, for a "rare" disease, case detection is more effective than population-based screening.

  11. The End of Population Growth in Asia

    OpenAIRE

    Lutz, W.; Scherbov, S.

    2002-01-01

    This paper presents probabilistic population projections for five regions of Asia (South Asia, Central Asia, China region, Pacific OECD and Pacific Asia) and Asia as a whole. Over this century, Asia will experience a very heterogeneous demographic development: Central Asia is still expected to almost double its population and South Asia will become by far the worlds most populous region, rapidly surpassing the China region. Simultaneously, todays Pacific OECD countries are likely to shrink in...

  12. Emergence of clones in sexual populations

    Science.gov (United States)

    Neher, Richard A.; Vucelja, Marija; Mezard, Mark; Shraiman, Boris I.

    2013-01-01

    In sexual population, recombination reshuffles genetic variation and produces novel combinations of existing alleles, while selection amplifies the fittest genotypes in the population. If recombination is more rapid than selection, populations consist of a diverse mixture of many genotypes, as is observed in many populations. In the opposite regime, which is realized for example in the facultatively sexual populations that outcross in only a fraction of reproductive cycles, selection can amplify individual genotypes into large clones. Such clones emerge when the fitness advantage of some of the genotypes is large enough that they grow to a significant fraction of the population despite being broken down by recombination. The occurrence of this ‘clonal condensation’ depends, in addition to the outcrossing rate, on the heritability of fitness. Clonal condensation leads to a strong genetic heterogeneity of the population which is not adequately described by traditional population genetics measures, such as linkage disequilibrium. Here we point out the similarity between clonal condensation and the freezing transition in the random energy model of spin glasses. Guided by this analogy we explicitly calculate the probability, Y, that two individuals are genetically identical as a function of the key parameters of the model. While Y is the analog of the spin-glass order parameter, it is also closely related to rate of coalescence in population genetics: two individuals that are part of the same clone have a recent common ancestor.

  13. Population development in Ljubljana urban region

    Directory of Open Access Journals (Sweden)

    Dejan Rebernik

    2004-12-01

    Full Text Available The paper presents the main characteristic of population development and urbanisation processes in Ljubljana and Ljubljana urban region. Up to the end of the seventies fast population growth was a consequence of strong immigration from rural parts of Slovenia and the rest of Yugoslavia. In the eighties and nineties deconcentration of population within the region with intense suburbanisation and depopulation of inner city and older residential neighbourhoods were the main urbanisation processes. In the second half of the nineties the highest population growth was recorded in dispersed rural settlements in the periphery of the region. In some parts of the inner city reurbanisation and gentrification occurred.

  14. Population control I: Birth of an ideology.

    Science.gov (United States)

    Hartmann, B

    1997-01-01

    Population control, as a major international development strategy, is a relatively recent phenomenon. However, its origins reach back to social currents in the 19th and early 20th centuries, culminating in an organized birth control movement in Europe and the United States. The conflicts and contradictions in that movement's history presage many of today's debates over population policy and women's rights. Eugenics had a deep influence on the U.S. birth control movement in the first half of the 20th century. After World War II private agencies and foundations played an important role in legitimizing population control as a way to secure Western control over Third World resources and stem political instability. In the late 1960s the U.S. government became a major funder of population control programs overseas and built multilateral support through establishment of the U.N. Fund for Population Activities. At the 1974 World Population Conference, Third World governments challenged the primacy of population control. While their critique led population agencies to change their strategies, population control remained a central component of international development and national security policies in the United States.

  15. Harvest and dynamics of duck populations

    Science.gov (United States)

    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.

  16. Population mobility and trypanosomiasis in Africa*

    Science.gov (United States)

    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

  17. Population growth and earth's human carrying capacity.

    Science.gov (United States)

    Cohen, J E

    1995-07-21

    Earth's capacity to support people is determined both by natural constraints and by human choices concerning economics, environment, culture (including values and politics), and demography. Human carrying capacity is therefore dynamic and uncertain. Human choice is not captured by ecological notions of carrying capacity that are appropriate for nonhuman populations. Simple mathematical models of the relation between human population growth and human carrying capacity can account for faster-than-exponential population growth followed by a slowing population growth rate, as observed in recent human history.

  18. Population distribution around French nuclear sites

    International Nuclear Information System (INIS)

    Bastien, M.C.

    1985-10-01

    With the help of two files respectively from the Institut geographique national (IGN) containing the geographic reference of all cities in France, and from the Institut national de la statistique et des etudes economiques (INSEE) containing the population figures of the 1982 census, the distribution of the population around a geographic point can be determined according to a given grid. Tables of population distribution around the 30 french nuclear sites were obtained by this method; however, at a short distance from a site, a detailed local examination/survey/investigation is necessary. Data shall have to be collected to estimate the non-french population around frontier sites [fr

  19. Population monotonic solutions on convex games

    OpenAIRE

    Toru Hokari

    2000-01-01

    The Dutta-Ray solution and the Shapley value are two well-known examples of population-monotonic solutions on the domain of convex games. We provide a new formula for the Dutta-Ray solution from which population-monotonicity immediately follows. Then we define a new family of population-monotonic solutions, which we refer to as "sequential Dutta-Ray solutions." We also show that it is possible to construct several symmetric and population-monotonic solutions by using the solutions in this fam...

  20. Population genomics of natural and experimental populations of guppies (Poecilia reticulata).

    Science.gov (United States)

    Fraser, Bonnie A; Künstner, Axel; Reznick, David N; Dreyer, Christine; Weigel, Detlef

    2015-01-01

    Convergent evolution represents one of the best lines of evidence for adaptation, but few cases of phenotypic convergence are understood at the genetic level. Guppies inhabiting the Northern Mountain Range of Trinidad provide a classic example of phenotypic convergent evolution, where adaptation to low or high predation environments has been found for a variety of traits. A major advantage of this system is the possibility of long-term experimental studies in nature, including transplantation from high to low predation sites. We used genome scans of guppies from three natural high and low predation populations and from two experimentally established populations and their sources to examine whether phenotypic convergent evolution leaves footprints at the genome level. We used population-genetic modelling approaches to reconstruct the demographic history and migration among sampled populations. Naturally colonized low predation populations had signatures of increased effective population size since colonization, while introduction populations had signatures of decreased effective population size. Only a small number of regions across the genome had signatures of selection in all natural populations. However, the two experimental populations shared many genomic regions under apparent selection, more than expected by chance. This overlap coupled with a population decrease since introduction provides evidence for convergent selection occurring in the two introduced populations. The lack of genetic convergence in the natural populations suggests that convergent evolution is lacking in these populations or that the effects of selection become difficult to detect after a long-time period. © 2014 John Wiley & Sons Ltd.

  1. Estimation of the Number of Microbial Species Comprising a Population

    National Research Council Canada - National Science Library

    Slattery, Melanie R

    2008-01-01

    ... comprising a population. This research consisted of creating diverse populations, with a known number of species, and applying the aforementioned methods to samples drawn from the constructed populations...

  2. The effects of harvest on waterfowl populations

    Science.gov (United States)

    Cooch, Evan G.; Guillemain, Matthieu; Boomer, G Scott; Lebreton, Jean-Dominique; Nichols, James D.

    2014-01-01

    Change in the size of populations over space and time is, arguably, the motivation for much of pure and applied ecological research. The fundamental model for the dynamics of any population is straightforward: the net change in the abundance is the simple difference between the number of individuals entering the population and the number leaving the population, either or both of which may change in response to factors intrinsic and extrinsic to the population. While harvest of individuals from a population constitutes a clear extrinsic source of removal of individuals, the response of populations to harvest is frequently complex, reflecting an interaction of harvest with one or more population processes. Here we consider the role of these interactions, and factors influencing them, on the effective harvest management of waterfowl populations. We review historical ideas concerning harvest and discuss the relationship(s) between waterfowl life histories and the development and application of population models to inform harvest management. The influence of population structure (age, spatial) on derivation of optimal harvest strategies (with and without explicit consideration of various sources of uncertainty) is considered. In addition to population structure, we discuss how the optimal harvest strategy may be influenced by: 1) patterns of density-dependence in one or more vital rates, and 2) heterogeneity in vital rates among individuals within an age-sex-size class. Although derivation of the optimal harvest strategy for simple population models (with or without structure) is generally straightforward, there are several potential difficulties in application. In particular, uncertainty concerning the population structure at the time of harvest, and the ability to regulate the structure of the harvest itself, are significant complications. We therefore review the evidence of effects of harvest on waterfowl populations. Some of this evidence has

  3. Major conference on population at Beijing.

    Science.gov (United States)

    1997-01-01

    This article discusses issues, such as the one child policy, which were the focus of the 23rd General Population Conference of the International Union for the Scientific Study of Population (IUSSP). IUSSP conferences are held every 4 years at a different site (the next conference in 2001 will be held in Brazil). This conference was organized by the China Population Association, the State Family Planning Commission, the UN Population Fund, and the IUSSP. The conference was attended by 1200 demographers and population workers from about 80 countries in the world. The opening address was given by the Chinese Premier H.E. Mr. Li Peng. The Vice-Minister of the State Family Planning Commission, Mr. Jiang Zhengua, affirmed the importance of the one child policy in the late 1970s in controlling population growth. China is the most populous country in the world with 1.242 billion people in mid-1997. Premier Li stated that the country would have had an additional 300 million people without a strict family limitation policy. The strict policy was necessary to reduce poverty for the 50 million living in the worst circumstances. The Director of the Population Division and ESCAP Officer in Charge of the secretariat reiterated the ICPD recommendations and concerns for adolescent programs, reproductive health programs, and migrants. An ESCAP Population Affairs Officer presented a paper on "The population of Cambodia, 1980-96." The closing ceremony speech was given by H.E. Ms. Peng Peiyun, the Chinese State Councilor and Minister in Charge of the State Family Planning Commission. The recommendations will be integrated into the High Level Meeting to review the implementation of ICPD Program of Action and the Bali Declaration on Population and Sustainable Development. The IUSSP Commission will consider the conference recommendations at its 54th session in April 1998.

  4. Impacts of climate change on avian populations.

    Science.gov (United States)

    Jenouvrier, Stephanie

    2013-07-01

    This review focuses on the impacts of climate change on population dynamics. I introduce the MUP (Measuring, Understanding, and Predicting) approach, which provides a general framework where an enhanced understanding of climate-population processes, along with improved long-term data, are merged into coherent projections of future population responses to climate change. This approach can be applied to any species, but this review illustrates its benefit using birds as examples. Birds are one of the best-studied groups and a large number of studies have detected climate impacts on vital rates (i.e., life history traits, such as survival, maturation, or breeding, affecting changes in population size and composition) and population abundance. These studies reveal multifaceted effects of climate with direct, indirect, time-lagged, and nonlinear effects. However, few studies integrate these effects into a climate-dependent population model to understand the respective role of climate variables and their components (mean state, variability, extreme) on population dynamics. To quantify how populations cope with climate change impacts, I introduce a new universal variable: the 'population robustness to climate change.' The comparison of such robustness, along with prospective and retrospective analysis may help to identify the major climate threats and characteristics of threatened avian species. Finally, studies projecting avian population responses to future climate change predicted by IPCC-class climate models are rare. Population projections hinge on selecting a multiclimate model ensemble at the appropriate temporal and spatial scales and integrating both radiative forcing and internal variability in climate with fully specified uncertainties in both demographic and climate processes. © 2013 Blackwell Publishing Ltd.

  5. Energy Systems and Population Health

    Energy Technology Data Exchange (ETDEWEB)

    Ezzati, Majid; Bailis, Rob; Kammen, Daniel M.; Holloway, Tracey; Price, Lynn; Cifuentes, Luis A.; Barnes, Brendon; Chaurey, Akanksha; Dhanapala, Kiran N.

    2004-04-12

    to rural and urban health facilities allows increased delivery and coverage of 3 various health services and interventions such as tests and treatments, better storage of medicine and vaccines, disinfection of medical equipment by boiling or radiation, and more frequent and efficient health system encounters through mobile clinics or longer working hours; and so on. In fact, while the dominant view of development-energy-health linkages has been that improvements in energy and health are outcomes of the socioeconomic development process (e.g., the ''energy ladder'' framework discussed below), it has even been argued that access to higher quality energy sources and technologies can initiate a chain of demographic, health, and development outcomes by changing the household structure and socioeconomic relationships. For example, in addition to increased opportunities for food and income production, reduced infant mortality as a result of transition to cleaner fuels or increased coverage of vaccination with availability of refrigerators in rural clinics may initiate a process of ''demographic transition'' to low-mortality and low-fertility populations (14). Such a transition has historically been followed with further improvements in maternal and child health and increased female participation in the labor markets and other economic activities.

  6. Population genomics of fungal and oomycete pathogens

    Science.gov (United States)

    We are entering a new era in plant pathology where whole-genome sequences of many individuals of a pathogen species are becoming readily available. This era of pathogen population genomics will provide new opportunities and challenges, requiring new computational and analytical tools. Population gen...

  7. The Soviet Union: Population Trends and Dilemmas.

    Science.gov (United States)

    Feshbach, Murray

    1982-01-01

    Recent trends and differentials among the Soviet Union's 15 republics and major nationalities are reviewed, focusing on fertility, mortality and urbanization, the prospect for labor supplies and military manpower, emigration, and projected population growth to 2000. Estimated at 270 million as of mid-1982, the Soviet population is currently…

  8. Population growth: Implications for environmental sustainability ...

    African Journals Online (AJOL)

    The impact of population growth on environment and its implication for survival is an important issue. Although considerable attention has been paid to this problem but systematic studies have been inadequate. Rapid population growth and economic development and daily demand for natural resources for domestic and ...

  9. [Recent population trends in the Swiss Alps].

    Science.gov (United States)

    Billet, J; Rougier, H

    1984-01-01

    Recent demographic trends in the Alpine areas of Switzerland are examined. Areas of population loss and gain are identified, and the importance of tourism for areas experiencing population growth is established. Efforts to support the demographic and economic viability of mountain areas are described.

  10. Sardinian Population (Italy): a Genetic Review

    African Journals Online (AJOL)

    thou

    Giuseppe Vona was born the 14/09/1938 in Frosinone (Italy). He is Full Professor of Anthropology at Cagliari University. He teaches also Biology of Human Populations, Population Genetics for the Course of Applied Bioecology. He has overseen groups engaged in research in projects financed by the University of Cagliari, ...

  11. People in Pixels: Gridding the World's Population

    Science.gov (United States)

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

    2017-12-01

    Fundamental to applications of land-use science is the spatiotemporal knowledge of the distribution, movement and concentration of human population. While census data is a historical source of population data, the past few decades have seen advancement in the techniques for creating gridded population products. These gridded population products provide a spatially-explicit human denominator, estimated for consistent areal units, from which a multitude of other research and policy initiatives rely. The importance of such products makes not only the accuracy of the population data important but also requires researchers and practitioners to understand how these data were created and how that constrains their use. We provide an overview of the different global gridded population products with insight on their production methods, from "lightly" modeled to more complex, statistical approaches. We also discuss considerations for different spatial and temporal aspects of gridded population data, with reference towards issues of endogeneity, temporal specificity, and spatial conformity. With various options available to the land change community for global, gridded population products, it is important to understand the differences between products and their best uses.

  12. Violent Offenders in a Deaf Prison Population

    Science.gov (United States)

    Miller, Katrina R.; Vernon, McCay; Capella, Michele E.

    2005-01-01

    Previous research suggested an unexplained difference in the patterns of offending behaviors among deaf people when compared to hearing people. This study, conducted in Texas, compares the incidence and types of violent offenses of a deaf prison population in comparison to the hearing prison population. Sixty-four percent of deaf prisoners were…

  13. Population and Reproductive Health in National Adaptation ...

    African Journals Online (AJOL)

    Erah

    environment” (Haiti), is “placing pressure on sensitive environments”(Tuvalu), and “tend[s] to degrade highland ecosystem” (Uganda). Population pressure is directly linked to deforestation in the NAPAs of Mozambique,. Rwanda, Sierra Leone, and Uganda. The Uganda. NAPA goes further in associating high population.

  14. The sensitivity analysis of population projections

    NARCIS (Netherlands)

    Caswell, H.; Sánchez Gassen, N.

    2015-01-01

    Background Population projections using the cohort component method can be written as time-varying matrix population models. The matrices are parameterized by schedules of mortality, fertility, immigration, and emigration over the duration of the projection. A variety of dependent variables are

  15. Metabolic variability in micro-populations.

    Science.gov (United States)

    Elhanati, Yuval; Brenner, Naama

    2012-01-01

    Biological cells in a population are variable in practically every property. Much is known about how variability of single cells is reflected in the statistical properties of infinitely large populations; however, many biologically relevant situations entail finite times and intermediate-sized populations. The statistical properties of an ensemble of finite populations then come into focus, raising questions concerning inter-population variability and dependence on initial conditions. Recent technologies of microfluidic and microdroplet-based population growth realize these situations and make them immediately relevant for experiments and biotechnological application. We here study the statistical properties, arising from metabolic variability of single cells, in an ensemble of micro-populations grown to saturation in a finite environment such as a micro-droplet. We develop a discrete stochastic model for this growth process, describing the possible histories as a random walk in a phenotypic space with an absorbing boundary. Using a mapping to Polya's Urn, a classic problem of probability theory, we find that distributions approach a limiting inoculum-dependent form after a large number of divisions. Thus, population size and structure are random variables whose mean, variance and in general their distribution can reflect initial conditions after many generations of growth. Implications of our results to experiments and to biotechnology are discussed.

  16. Metabolic variability in micro-populations.

    Directory of Open Access Journals (Sweden)

    Yuval Elhanati

    Full Text Available Biological cells in a population are variable in practically every property. Much is known about how variability of single cells is reflected in the statistical properties of infinitely large populations; however, many biologically relevant situations entail finite times and intermediate-sized populations. The statistical properties of an ensemble of finite populations then come into focus, raising questions concerning inter-population variability and dependence on initial conditions. Recent technologies of microfluidic and microdroplet-based population growth realize these situations and make them immediately relevant for experiments and biotechnological application. We here study the statistical properties, arising from metabolic variability of single cells, in an ensemble of micro-populations grown to saturation in a finite environment such as a micro-droplet. We develop a discrete stochastic model for this growth process, describing the possible histories as a random walk in a phenotypic space with an absorbing boundary. Using a mapping to Polya's Urn, a classic problem of probability theory, we find that distributions approach a limiting inoculum-dependent form after a large number of divisions. Thus, population size and structure are random variables whose mean, variance and in general their distribution can reflect initial conditions after many generations of growth. Implications of our results to experiments and to biotechnology are discussed.

  17. The failure rate dynamics in heterogeneous populations

    International Nuclear Information System (INIS)

    Cha, Ji Hwan; Finkelstein, Maxim

    2013-01-01

    Most populations encountered in real world are heterogeneous. In reliability applications, the mixture (observed) failure rate, obviously, can be considered as a measure of ‘average’ quality in these populations. However, in addition to this average measure, some variability characteristics for failure rates can be very helpful in describing the time-dependent changes in quality of heterogeneous populations. In this paper, we discuss variance and the coefficient of variation of the corresponding random failure rate as variability measures for items in heterogeneous populations. Furthermore, there is often a risk that items of poor quality are selected for important missions. Therefore, along with the ‘average quality’ of a population, more ‘conservative’ quality measures should be also defined and studied. For this purpose, we propose the percentile and the tail-mixture of the failure rates as the corresponding conservative measures. Some illustrative examples are given. -- Highlights: ► This paper provides the insight on the variability measures in heterogeneous populations. ► The conservative quality measures in heterogeneous populations are defined. ► The utility of these measures is illustrated by meaningful examples. ► This paper provides a better understanding of the dynamics in heterogeneous populations

  18. Stochastic population dynamic models as probability networks

    Science.gov (United States)

    M.E. and D.C. Lee. Borsuk

    2009-01-01

    The dynamics of a population and its response to environmental change depend on the balance of birth, death and age-at-maturity, and there have been many attempts to mathematically model populations based on these characteristics. Historically, most of these models were deterministic, meaning that the results were strictly determined by the equations of the model and...

  19. Scaling of Attitudes Toward Population Problems

    Science.gov (United States)

    Watkins, George A.

    1975-01-01

    This study related population problem attitudes and socioeconomic variables. Six items concerned with number of children, birth control, family, science, economic depression, and overpopulation were selected for a Guttman scalogram. Education, occupation, and number of children were correlated with population problems scale scores; marital status,…

  20. The Population Problem as Economic Disarticulation.

    Science.gov (United States)

    Yapa, Lakshman S.

    1985-01-01

    Overpopulation exists when people lack the basic means of subsistence, or when there is massive and permanent unemployment. Population problems of developing countries are examined, and causes of high rates of fertility are discussed. The utilization of productive resources in solving population problems is also examined. (RM)

  1. Methods Needed to Curb Rising Pet Population

    Science.gov (United States)

    Chemical and Engineering News, 1973

    1973-01-01

    Discusses socioeconomic problems of pet population explosion and recommends the conduct of educational programs and the implementation of surgical sterilization as a short-term answer to dog and cat control. Also considered are problems of using chemical contraceptives in human population control. (CC)

  2. Population and Child Spacing Information, Education and ...

    African Journals Online (AJOL)

    P.O. Box 280. Zomba. Malawi. Population and Child Spacing. Information, Education and. Communication Activities. Mr. R.C.D. Ngaiyaye. Several agencies are involved in providing Child Spacing (CS) and population infonnation, education and communication. (lEG). They use almost all communication channels available.

  3. Genetic variation between ecotypic populations of Chloris ...

    African Journals Online (AJOL)

    Genetic variation between ecotypic populations of Chloris roxburghiana grass detected through RAPD analysis. ... frequency indicated that the four populations of C. roxburghiana were genetically distinct, probably as a result of variation in soil fertility, geographical isolation and socio-ecological history of the study sites.

  4. POPULATION GROWTH AND HEALTH CARE DELIVERY IN ...

    African Journals Online (AJOL)

    Adamawa state population is projected to be approximately 2,819million by the year 2001. This gives an increase of 716,784 as compared to the 1991 census figure, which is 2,102,053 for the state. The last census (1991) formed the basis of this projection. Further,1996 projected population was projected to the year 2001.

  5. The population factor in economic growth theory

    NARCIS (Netherlands)

    Meilink, H.A.

    1974-01-01

    Reviews briefly the role of population growth in economic growth theory and makes a few critical remarks on the applied methodology and the underlying assumptions. Emphasis is laid on the possible relationships between population and economic growth in the developing countries, but also Malthus'

  6. Hidden ion population of the magnetosphere

    International Nuclear Information System (INIS)

    Olsen, R.C.

    1982-01-01

    Particle data from two geosynchronous satellites (Applied Technology Satellite 6 and SCATHA) show a normally hidden ion population appearing when the satellites are in the earth's shadow. Ion and electron data show the spacecraft potential dropping from +10 V in sunlight to +4 and +5 V in eclipse at local midnight, in low-energy (T/sub e/ -2 ), isotropic ion population appears which was invisible in sunlight because of the larger positive spacecraft potential. Higher-energy populations generally cover the tails of the hidden ion populations, so they cannot be inferred from daylight data. The isotropic populations appears only in a few percent of the spacecraft eclipse events, appearing only at times of low Kp (2 or less, preceded by a day with Σ Kp< or =20). A low-energy (T = 1--2 eV) field-aligned population often appears with and without the isotropic population, at slightly higher flux levels. These fluxes are visible in sunlight, but again the distribution functions obtained in eclipse differ from those that would be inferred from daylight data. Measurement of the thermal plasma population on a consistent basis, particularly in the plasma sheet, will require some method of controlling the detector potential with respect to the ambient plamsa

  7. Microbial population changes in tropical agricultural soil ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-12-17

    Dec 17, 2008 ... that the increase in microbial population was the key factor responsible for oil depletion. As depicted in Figure 2, the population densities of heterotrophic bacteria, fungi, actinomycetes, and nitrogen-fixers were higher during the first 16 weeks of study in the control soil. This trend readily suggests toxicity of ...

  8. Genetic variation and population structure in Oryza ...

    Indian Academy of Sciences (India)

    We assessed the nature and distribution of genetic variation among 11 populations of O. malampuzhaensis using random amplified polymorphic DNA markers. The analysis revealed low genetic variation in O. malampuzhaensis. Cluster analysis of pairwise genetic distances of populations revealed three distinct clusters ...

  9. Population Problems and Family Planning in Africa.

    Science.gov (United States)

    Uche, Chukwudum

    The focal points of this essay are the population problems in Africa and what the African peoples and governments are doing about them. It is stated cagegorically that a problem does exist. Indicators often used to deny this position are population density and pressure, undeveloped resources, the availability of empty lands, and alleged intrigue…

  10. Microsatellite data analysis for population genetics

    Science.gov (United States)

    Theories and analytical tools of population genetics have been widely applied for addressing various questions in the fields of ecological genetics, conservation biology, and any context where the role of dispersal or gene flow is important. Underlying much of population genetics is the analysis of ...

  11. Genetic structure of Potentilla acaulis (Rosaceae) populations ...

    African Journals Online (AJOL)

    Genetic structure of Potentilla acaulis (Rosaceae) populations based on randomly amplified polymorphic DNA (RAPD) in habitat fragmented grassland of northern ... attention from a conservation point of view and it should be considered as a conservation strategy to increasing gene exchange among isolated populations.

  12. Planning for an ageing population: strategic considerations

    LENUS (Irish Health Repository)

    O'Shea, Dr Eamon

    2005-01-01

    This report presents both the proceedings of the Council’s conference, Planning for an Ageing Population: Strategic Considerations, and the Council’s discussion paper, ‘The Older Population: Information Issues and Deficits’, which was introduced at that conference.\\r\

  13. Sampling Lesbian, Gay, and Bisexual Populations

    Science.gov (United States)

    Meyer, Ilan H.; Wilson, Patrick A.

    2009-01-01

    Sampling has been the single most influential component of conducting research with lesbian, gay, and bisexual (LGB) populations. Poor sampling designs can result in biased results that will mislead other researchers, policymakers, and practitioners. Investigators wishing to study LGB populations must therefore devote significant energy and…

  14. Population Parameters of Brackish River Prawn ( Macrobrachium ...

    African Journals Online (AJOL)

    The population parameters of Macrobrachium macrobrachion in the Lower Taylor Creek, Niger Delta, Nigeria were estimated using a – 24 month length – frequency data (June 2008 – May 2010). The FAO-ICLARM Stock Assessment Tool (FiSAT II) software was used to estimate the population parameters. The estimated ...

  15. Assessing population structure: FST and related measures

    NARCIS (Netherlands)

    Meirmans, P.G.; Hedrick, P.W.

    2011-01-01

    Although FST is widely used as a measure of population structure, it has been criticized recently because of its dependency on within-population diversity. This dependency can lead to difficulties in interpretation and in the comparison of estimates among species or among loci and has led to the

  16. Scale Reliability Evaluation with Heterogeneous Populations

    Science.gov (United States)

    Raykov, Tenko; Marcoulides, George A.

    2015-01-01

    A latent variable modeling approach for scale reliability evaluation in heterogeneous populations is discussed. The method can be used for point and interval estimation of reliability of multicomponent measuring instruments in populations representing mixtures of an unknown number of latent classes or subpopulations. The procedure is helpful also…

  17. Adult African sharptooth catfish, Clarias gariepinus , population ...

    African Journals Online (AJOL)

    The skewed length- and age-structure suggests that the adult population is dominated by the fish that were either the initial colonizers during the reservoir filling phase or were the first internally reproduced recruits. The predominance of old, large fish in the population is also probably suppressing recruitment of younger fish.

  18. Population analysis for atomic cascade decay processes

    International Nuclear Information System (INIS)

    Suto, Keiko; Kagawa, Takashi; Futaba, Kaoru

    1998-01-01

    Down-stream cascade decay processes in atomic systems are analyzed by solving a coupled rate equation for which an analytical solution for a population in each excited state is obtained. Some typical numerical examples for populations to interpret the decay passes connecting to features of optical or electron spectra observed in various collision experiments are also given. (author)

  19. Social stress and population cycles: an assessment

    International Nuclear Information System (INIS)

    Novak, M.A.

    1978-01-01

    Social stress is a population hypothesis that is invoked to explain the precipitous declines observed in population levels of such rodent species as Microtus pennsylvanicus. According to this hypothesis, stress is produced by the increase in aggressive contacts between animals in a growing population. Continued contacts produce profound hormonal and behavioral changes in these animals which lead to decreases in reproduction and viability. Several theoretical weaknesses of the hypothesis are raised. First, increases in density may not be positively correlated with the number of contacts. Animals may merely build more runways. Second, even if contacts do increase, they may not necessarily be aggressive in nature. Finally, confined populations which reach excessively high densities and for which contacts between animals must increase, fail to show a precipitous decline in numbers. In addition, a major methodological problem is revealed. Although researchers tend to causally connect social stress and precipitous population declines, most studies are correlational in nature. Of those studies that involve actual manipulations of populations, these manipulations are usually performed on confined populations that fail to exhibit the desired phenomonen. The difficulties associated with manipulating unconfined populations are discussed

  20. Estimating total population size for Songbirds

    Science.gov (United States)

    Jonathan Bart

    2005-01-01

    A conviction has developed during the past few years within the avian conservation community that estimates of total population size are needed for many species, especially ones that warrant conservation action. For example, the recently completed monitoring plans for North American shorebirds and landbirds establish estimating population size as a major objective....

  1. Synchronization and survival of connected bacterial populations

    Science.gov (United States)

    Gokhale, Shreyas; Conwill, Arolyn; Ranjan, Tanvi; Gore, Jeff

    Migration plays a vital role in controlling population dynamics of species occupying distinct habitat patches. While local populations are vulnerable to extinction due to demographic or environmental stochasticity, migration from neighboring habitat patches can rescue these populations through colonization of uninhabited regions. However, a large migratory flux can synchronize the population dynamics in connected patches, thereby enhancing the risk of global extinction during periods of depression in population size. Here, we investigate this trade-off between local rescue and global extinction experimentally using laboratory populations of E. coli bacteria. Our model system consists of co-cultures of ampicillin resistant and chloramphenicol resistant strains that form a cross-protection mutualism and exhibit period-3 oscillations in the relative population density in the presence of both antibiotics. We quantify the onset of synchronization of oscillations in a pair of co-cultures connected by migration and demonstrate that period-3 oscillations can be disturbed for moderate rates of migration. These features are consistent with simulations of a mechanistic model of antibiotic deactivation in our system. The simulations further predict that the probability of survival of connected populations in high concentrations of antibiotics is maximized at intermediate migration rates. We verify this prediction experimentally and show that survival is enhanced through a combination of disturbance of period-3 oscillations and stochastic re-colonization events.

  2. Bivalves: From individual to population modelling

    NARCIS (Netherlands)

    Saraiva, S.; van der Meer, J.; Kooijman, S.A.L.M.

    2014-01-01

    An individual based population model for bivalves was designed, built and tested in a 0D approach, to simulate the population dynamics of a mussel bed located in an intertidal area. The processes at the individual level were simulated following the dynamic energy budget theory, whereas initial egg

  3. Population structure of Atlantic Mackerel (Scomber scombrus)

    DEFF Research Database (Denmark)

    Jansen, Teunis; Gislason, Henrik

    2013-01-01

    model where the population structure of mackerel is described as a dynamic cline, rather than as connected contingents. Temporal changes in hydrography and mackerel behavior may affect the steepness of the cline at various locations. The new interpretation of the population structure of Atlantic...

  4. [Population characterization of Timor-East].

    Science.gov (United States)

    Carvalho, A C

    1985-01-01

    The population characterization of Timor-East, Province of Portugal, is described from the demographic and socioeconomic point of views. Although several population censuses had been carried out in the Portuguese province, only the results from the 1970 census provide an analysis of the population characteristics. According to the results of the 1970 census, the population had grown 1.6%/year between 1950-70. 50% of the population was less than 20 years old in 1970, and only 4% were elderly. Marriage was very common. 93.1% of the women and 92.8% of the men were married. 3 out of 4 people followed the Animist or Buddhism religions and only 25% were Catholics. 90.4% of the surveyed population were illiterate. The poverty is reflected by the low mean of life expectancy: 45 years. Fecundity rate was 5.1 children/woman. With the hypothesis of a natural and constant population growth, the Timor-East should have had around 840 thousand people in 1980, and doubling beginning of next century. Nevertheless, history shows a different reality. Because of the civil war and invasion and later occupation of the Province by the Indonesian forces, the population reached only 550 thousand in 1980.

  5. Understanding the population dimension in development planning.

    Science.gov (United States)

    Rivera, P C

    1983-01-01

    In the Philippines initial efforts to adopt population policies focused on reducing rapid population growth through fertility control. The history of the national population welfare congress, which started in 1978, reflects this emphasis on family planning as a major deterrent to rapid population growth. It was only in recent years that the 2-way relationship between population and development came to be better appreciated. The 6th National Populaton Welfare Congress was a response to this need to broaden the scope of population concerns and integrate the population dimension into development planning. This viewpoint regards population not as a demand variable but as a factor that can be influenced by economic and social development. Dr. Mercedes B. Concepcion, dean of the University of the Philippines Population Institute (UPPI), discussed population trends, prospects, and problems in a paper presented before the 6th congress. In 1980, she said, the Philippine population was 48.1 million persons, up by 11.4 million persons or 31%, over the3l.7 million enumerated in 1970. While the rate of populated growth remains high, data indicate a decreasing post-World War II trend, from 3.06% in 1948-60 to 2.68% in 1975-80. The proportion of the population below 15 has dropped by 2 percentage points, while the number of persons in the working ages 15-64 has increased. In 1 of the 3 group sessions during the congress, the participants tried to define the Philippines' population distribution goals, the requirement of an urban-rural balance, and priority intervention areas. In that session 2 main papers were presented -- one on human settlements and urbanization and the other on macroeconomic policies and their spatial implications. In another sessionplanners and researchers examined the socioeconomic and demographic impact of development programs, specifically the impact of rural electrification on fertility change in Misamis Oriental, a province in Southern Philippines. In the

  6. Population structure and adaptation in fishes

    DEFF Research Database (Denmark)

    Limborg, Morten

    . Comprehensive genetic analyses on the small pelagic fish European sprat (Sprattus sprattus) revealed significant population structure throughout its distribution with an overall pattern of reduced connectivity across environmental transition zones. Population structure reflected both historical separations over......Marine fishes represent a valuable resource for the global economy and food consumption. Accordingly, many species experience high levels of exploitation necessitating effective management plans. However, long term sustainability may be jeopardized from insufficient knowledge about intra......-specific population structure and adaptive divergence. The large population sizes and high migration rates common to most marine fishes impede the differentiating effect of genetic drift, having led to expectations of no population structure and that the occurrence of local adaptation should be rare in these species...

  7. Underground population defense structures in China

    Energy Technology Data Exchange (ETDEWEB)

    Wukasch, E.

    The design and construction ofunderground shelters to protect the Chinese population in the event of nuclear war are described. Built in the style of World War II air raid shelters and designed as neighborhood defense facilities, these are not judged to be adequate for nuclear defense needs, particularly the needs of urban populations. However, 80% of China's population is rural and 1/3 of this has lived underground for centuries in cliff dwellings and atrium houses. It is, therefore, concluded that China's rural population has a better chance the the population of any other country for long-term survival from the later consequences, as well as the immediate shock, of an urban nuclear attack. (LCL)

  8. Ordering structured populations in multiplayer cooperation games

    Science.gov (United States)

    Peña, Jorge; Wu, Bin; Traulsen, Arne

    2016-01-01

    Spatial structure greatly affects the evolution of cooperation. While in two-player games the condition for cooperation to evolve depends on a single structure coefficient, in multiplayer games the condition might depend on several structure coefficients, making it difficult to compare different population structures. We propose a solution to this issue by introducing two simple ways of ordering population structures: the containment order and the volume order. If population structure is greater than population structure in the containment or the volume order, then can be considered a stronger promoter of cooperation. We provide conditions for establishing the containment order, give general results on the volume order, and illustrate our theory by comparing different models of spatial games and associated update rules. Our results hold for a large class of population structures and can be easily applied to specific cases once the structure coefficients have been calculated or estimated. PMID:26819335

  9. Elucidating population histories using genomic DNA sequences.

    Science.gov (United States)

    Vigilant, Linda

    2009-04-01

    In 1993, Cliff Jolly suggested that rather than debating species definitions and classifications, energy would be better spent investigating multidimensional patterns of variation and gene flow among populations. Until now, however, genetic studies of wild primate populations have been limited to very small portions of the genome. Access to complete genome sequences of humans, chimpanzees, macaques, and other primates makes it possible to design studies surveying substantial amounts of DNA sequence variation at multiple genetic loci in representatives of closely related but distinct wild primate populations. Such data can be analyzed with new approaches that estimate not only when populations diverged but also the relative amounts and directions of subsequent gene flow. These analyses will reemphasize the difficulty of achieving consistent species and subspecies definitions by revealing the extent of variation in the amount and duration of gene flow accompanying population divergences.

  10. Critique of zero population growth theory.

    Science.gov (United States)

    Bhattacharya, D

    1993-04-01

    This is a critique of widely held theories concerning the relationship between population growth and economic development. "The central purpose of this paper is to critically analyse the zero population growth movement. The hypotheses of Neo-Malthusian theory or Zero Population Growth and the concept of Population Bomb will be briefly stated in Section 1. Section 2 will discuss the theory of demographic transition. Section 3 will critically examine the validity of the Neo-Malthusian theory of population growth. Our conclusions and recommendations will be stated in Section 4." The author's main contention is that overconsumption in developed countries is the major cause of the deterioration of the environment rather than overpopulation in the developing countries. excerpt

  11. Common bunt resistant wheat composite cross populations

    DEFF Research Database (Denmark)

    Steffan, Philipp Matthias; Borgen, A.; Backes, Gunter Martin

    stability. However, a number of challenges must be met before diverse wheat populations can be introduced into commercial wheat production: one of these is the development of breeding technologies based on mass selection which enable breeders and farmers to improve specific traits in populations...... and maintain diversity at the same time. BIOBREED is a project which commenced in Denmark in 2011 to meet these challenges for wheat population breeding. The project focuses on the development of tools and methods for mass selection of traits relevant for organic and low input production, where it is expected...... that the highest benefits of utilizing diverse populations can be achieved. BIOBREED focuses on three main aspects of wheat population breeding for organic and low input production systems: i) common bunt (caused by Tilletia caries) resistance, ii) selection for improved protein content and iii) the influence...

  12. Population genetics models of local ancestry.

    Science.gov (United States)

    Gravel, Simon

    2012-06-01

    Migrations have played an important role in shaping the genetic diversity of human populations. Understanding genomic data thus requires careful modeling of historical gene flow. Here we consider the effect of relatively recent population structure and gene flow and interpret genomes of individuals that have ancestry from multiple source populations as mosaics of segments originating from each population. This article describes general and tractable models for local ancestry patterns with a focus on the length distribution of continuous ancestry tracts and the variance in total ancestry proportions among individuals. The models offer improved agreement with Wright-Fisher simulation data when compared to the state-of-the art and can be used to infer time-dependent migration rates from multiple populations. Considering HapMap African-American (ASW) data, we find that a model with two distinct phases of "European" gene flow significantly improves the modeling of both tract lengths and ancestry variances.

  13. The Canarian Camel: A Traditional Dromedary Population

    Directory of Open Access Journals (Sweden)

    Ursula Schulz

    2010-04-01

    Full Text Available The domestic camel (dromedary is the most important livestock species in the Canary Islands and the most important autochthonous European camel population. After six centuries of a successful adaptation process to the particular environment of the Canary Islands, the abandonment of traditional agriculture has led this population to a major bottleneck. Along with a lack of foreign genetic interchanges, this could lead the population to the brink of extinction. Genetic analysis using 13 microsatellites showed the closest genetic proximity to the North African (Tindouf, Algeria camel population and a certain degree of sub-division, with significant genetic differences among breeders. An important level of genetic differentiation among the different populations analyzed was found with a global FST value of 0.116.

  14. Complexity in a population of Artemia

    Energy Technology Data Exchange (ETDEWEB)

    Ali, A.A., E-mail: abduladem1@yahoo.co [Electrical Engineering Department, University of Basrah (Iraq); Fortuna, L., E-mail: lfortuna@diees.unict.i [DIEEI, Faculty of Engineering, University of Catania (Italy); Frasca, M., E-mail: mfrasca@diees.unict.i [DIEEI, Faculty of Engineering, University of Catania (Italy); Rashid, M.T., E-mail: mofid76@yahoo.co [Electrical Engineering Department, University of Basrah (Iraq); Xibilia, M.G., E-mail: mxibilia@ingegneria.unime.i [DiSIA, Faculty of Engineering, University of Messina (Italy)

    2011-04-15

    Highlights: Experiments on collective motion of populations of animals (Artemia salina). Design of low-cost experimental setup for complex systems. Control of collective motion of populations of Artemia. Models of collective motion of populations of Artemia. - Abstract: Artemia salina belongs to a genus of very primordial crustaceans, whose behavior is not widely investigated in literature. Their collective behavior is studied in this paper both experimentally and theoretically. Different experiments have been designed to control the direction of motion of an Artemia population by exploiting their sensitivity to light and to measure the response of the population to light at different wavelengths. Mathematical models have been also derived, explaining the mechanisms underlying Artemia flocking formation when a light spot is applied to the system. The results obtained allow to develop new strategies for distributed control of agents and to test them in a simple and low cost experimental setup.

  15. Complexity in a population of Artemia

    International Nuclear Information System (INIS)

    Ali, A.A.; Fortuna, L.; Frasca, M.; Rashid, M.T.; Xibilia, M.G.

    2011-01-01

    Highlights: → Experiments on collective motion of populations of animals (Artemia salina). → Design of low-cost experimental setup for complex systems. → Control of collective motion of populations of Artemia. → Models of collective motion of populations of Artemia. - Abstract: Artemia salina belongs to a genus of very primordial crustaceans, whose behavior is not widely investigated in literature. Their collective behavior is studied in this paper both experimentally and theoretically. Different experiments have been designed to control the direction of motion of an Artemia population by exploiting their sensitivity to light and to measure the response of the population to light at different wavelengths. Mathematical models have been also derived, explaining the mechanisms underlying Artemia flocking formation when a light spot is applied to the system. The results obtained allow to develop new strategies for distributed control of agents and to test them in a simple and low cost experimental setup.

  16. Kuroda named for UN population award.

    Science.gov (United States)

    1997-04-01

    This article focuses on the accomplishments of a prominent Japanese demographer, Toshio Kuroda, and his receipt of the 1997 UN Population Award. Kuroda is director emeritus of the Nihon University Population Research Institute and a board member of JOICFP. He was honored for his research, publications, and leadership contributions in Japan and throughout Asia and the world. His first population experience was with the Institute of Population Problems of the Japanese Ministry of Health and Welfare in 1947. Eventually he became director of the Institute before assuming a position at Nihon University as director of NUPRI. Kuroda served as a Japanese representative in the UN Population Commission, at the 1972 Stockholm Conference on the Environment, and at the 1974 Bucharest International Conference on Population. He served as a resource person for Asian population conferences, Japanese nongovernmental groups, and the Mainichi Newspapers Population Problems Research Council. He developed a reputation as a consensus builder among Japanese leaders and policymakers, has maintained a long-standing relationship with JOICFP, and served as a resource person at its many forums and training courses. Since 1985 he has served as a major resource person on JOICFP's aging program for the Asian region. Since 1988 he has supervised the development of UNFPA's annual State of World Population Report for Japan. Kuroda is known for his views on the integration of micro- and macrolevels of analysis and discussion. He believes that a high level of education is key to the promotion of family planning. Girls should be enrolled in school through high school. Toshio Kuroda was one of three people and the second Japanese person to receive the UN Population Award.

  17. Mechanisms Affecting Population Density in Fragmented Habitat

    Directory of Open Access Journals (Sweden)

    Lutz Tischendorf

    2005-06-01

    Full Text Available We conducted a factorial simulation experiment to analyze the relative importance of movement pattern, boundary-crossing probability, and mortality in habitat and matrix on population density, and its dependency on habitat fragmentation, as well as inter-patch distance. We also examined how the initial response of a species to a fragmentation event may affect our observations of population density in post-fragmentation experiments. We found that the boundary-crossing probability from habitat to matrix, which partly determines the emigration rate, is the most important determinant for population density within habitat patches. The probability of crossing a boundary from matrix to habitat had a weaker, but positive, effect on population density. Movement behavior in habitat had a stronger effect on population density than movement behavior in matrix. Habitat fragmentation and inter-patch distance may have a positive or negative effect on population density. The direction of both effects depends on two factors. First, when the boundary-crossing probability from habitat to matrix is high, population density may decline with increasing habitat fragmentation. Conversely, for species with a high matrix-to-habitat boundary-crossing probability, population density may increase with increasing habitat fragmentation. Second, the initial distribution of individuals across the landscape: we found that habitat fragmentation and inter-patch distance were positively correlated with population density when individuals were distributed across matrix and habitat at the beginning of our simulation experiments. The direction of these relationships changed to negative when individuals were initially distributed across habitat only. Our findings imply that the speed of the initial response of organisms to habitat fragmentation events may determine the direction of observed relationships between habitat fragmentation and population density. The time scale of post

  18. Population growth and development: the Kenyan experience.

    Science.gov (United States)

    Nyamwange, M

    1995-01-01

    Rapid population growth in Kenya and high fertility impacts negatively on economic development. The growth and high fertility results in declines in gross national product, per capita food consumption, and land quality; a high dependency ratio; urban crowding; and inadequate health systems. East Africa has the highest crude birth rates in Africa, and Kenya has the highest birth rate of 54/1000 population in East Africa. The African crude death rate is 50% higher than the world average, but Kenya's death rate is the lowest in East Africa and comparable to North American and European death rates. Kenya has the highest rate of natural increase of about 4%. Population growth rates rose over the decades. Kenya's average population density is well above the sub-Saharan African average and much lower than very high density countries. Population is unequally distributed. Regional densities are widely divergent, and the highest densities in Western province are well above densities in Rwanda and Burundi. Urban growth has increased, as has migration to urban areas. Nairobi has 57% of urban population. Improved health and nutrition have contributed to increased life expectancy. The desired family size is large. The impact of demographic factors on economic conditions is evident in the decline in gross national product per capita growth to under 1% during 1972-88. A slight upswing occurred during 1988-93, but other crises are emerging. Food production has not kept pace with population growth. Production has been low due to serious land degradation, short fallow periods, and traditional farming practices. Population pressure has forced families to shift agriculture onto marginal lands, and desertification has increased. A growing proportion of the population is unemployed or underemployed. Population programs should address the underlying conditions for fertility decline.

  19. Declaration of the Population Policy [April 1988].

    Science.gov (United States)

    1989-01-01

    The Declaration of the Population Policy, Ministry of Planning and Cooperation, Directorate of Human Resources, 1988, of Senegal begins with the basic principles of the population policy. The intervention by the State into "individual" problems is justified by the Constitution authorizing concrete action in all areas of national life, including population and family life, where the social and economic improvement of Senegal and the entire African continent rests. The population policy takes into account demographic, economic, social, and cultural factors, as well as respect for the fundamental rights of individual persons, the necessity of preserving the family unit, and respect for the rights of individuals and couples to choose the size of their family and to control their fertility. The policy's objectives are defined and include the reduction of morbidity and mortality rates, particularly among mothers and infants, by instituting maternal-child health programs, including family planning. While it would be premature to determine quantitative demographic objectives, reviewing demographic perspectives can clarify future choices, and tables are provided. Section 3.3 defines the following population policy strategies: maternal-child health; fertility and birth spacing; promotion of women (status of women); promotion of youth; promotion of the elderly; preservation of the family; migration, urbanization, and management of territory; employment; studies and research (on population, fertility, demographic and health, infant mortality, and a general population census); information, education, and communication on the population issues; and legislative measures and regulation. The institutional framework will be advanced through the efforts of several kinds of specified institutions, among them: The Interministerial Council on Population, presided over by the Head of States; the National Population Commission; the Directorate of Human Resources; the Ministry of Public

  20. Population, resources, environment: an uncertain future.

    Science.gov (United States)

    Repetto, R

    1987-07-01

    This issue analyzes the economic and environmental consequences of rapid population growth in developing countries (LDC), the population decline in developed countries, the limits that life on a finite planet impose on economic and demographic expansion and progress, and the proper governmental response to promote the welfare of its current and future citizens. The links between population growth, resource use, and environmental quality are too complex to permit straightforward generalizations about direct causal relationships. However, rapid population growth has increased the number of poor people in LDC, thus contributing to degradation of the environment and the renewable resources of land, water, and nonhuman species on which humans depend. Demands of the rich industrial countries have also generated environmental pressures and have been foremost in consumption of the nonrenewable resources of fossil fuels, metals, and nonmetallic minerals. On the other hand, population and economic growth have also stimulated technological and management changes that help supply and use resources more effectively. Wide variations in the possible ultimate size of world population and accelerating technological change make future interrelationships of population, resources, and the environment uncertain as well as complex. Those interrelationships are mediated largely by government policies. Responsible governments can bring about a sustainable balance in the population/resource/environment equation by adopting population and development policies that experience has shown could reduce future population numbers in LDC below the additional 5 billion indicated in current UN medium projections. This coupled with proven management programs in both LDC and developed countries could brake and reverse the depletion and degradation of natural resources.