WorldWideScience

Sample records for fertility populations meanings

  1. Frustrated fertility: a population paradox.

    Science.gov (United States)

    Mcfalls Ja, J

    1979-05-01

    This Bulletin examines the causes of subfecundity -- the diminished ability to reproduce -- and its effect today and in the past on the fertility, or actual reproductive performance, of individuals and, hence, populations. By definition, all real populations are subfecund since all experience some degree of involuntary biological factors affecting coitus, conception, or the ability to carry a conceptus to live birth which reduces their fecundity below the estimated biological population maximum of 15 children per woman. Affecting both men and women, these factors fall into 5 categories: genetic factors such as blood group incompatibilities and inherited sickle cell anemia or diabetes; psychopathology, including psychic stress and behavioral disorders (e.g., drug and alcohol abuse); infectious diseases such as gonorrhea, malaria, tuberculosis, and postabortion infection; malnutrrition, including the chronic undernutrition of the 3rd World and the overnutrition of developed societies; and hazards posed by increasing amounts of radiation and toxic chemicals in the environment. Reducing subfecundity requires improved living conditions, avoidance of or protection from known hazards, and adoption of medical advances which now can help 40 to 60% of subfecund couples. But even in the U.S. fertility would certainly rise among the 15% of couples now estimated to be involuntarily childless and the 10% who have fewer children than they want, and among disadvantaged groups, and teenagers.

  2. Ocean fertilization: a potential means of geoengineering?

    Science.gov (United States)

    Lampitt, R S; Achterberg, E P; Anderson, T R; Hughes, J A; Iglesias-Rodriguez, M D; Kelly-Gerreyn, B A; Lucas, M; Popova, E E; Sanders, R; Shepherd, J G; Smythe-Wright, D; Yool, A

    2008-11-13

    The oceans sequester carbon from the atmosphere partly as a result of biological productivity. Over much of the ocean surface, this productivity is limited by essential nutrients and we discuss whether it is likely that sequestration can be enhanced by supplying limiting nutrients. Various methods of supply have been suggested and we discuss the efficacy of each and the potential side effects that may develop as a result. Our conclusion is that these methods have the potential to enhance sequestration but that the current level of knowledge from the observations and modelling carried out to date does not provide a sound foundation on which to make clear predictions or recommendations. For ocean fertilization to become a viable option to sequester CO2, we need more extensive and targeted fieldwork and better mathematical models of ocean biogeochemical processes. Models are needed both to interpret field observations and to make reliable predictions about the side effects of large-scale fertilization. They would also be an essential tool with which to verify that sequestration has effectively taken place. There is considerable urgency to address climate change mitigation and this demands that new fieldwork plans are developed rapidly. In contrast to previous experiments, these must focus on the specific objective which is to assess the possibilities of CO2 sequestration through fertilization.

  3. [Fertility pattern of contemporary peasant and population control].

    Science.gov (United States)

    Huang, Z

    1991-04-01

    The fertility decline among people in rural areas of China where 80% of the country's population reside is the key issue in the solution of population problems in China. But the current fertility in rural areas is far above the level of government population policy requirement. Field studies and newspaper reports in some rural provinces in 1989 suggested that the prevalent family pattern among farmers is 2 sons and 1 daughter. In order to have at least 1 son, some rural families would keep having children even if they have to pay fines. The fertility aspiration of rural families could be attributed to numerous factors. The Chinese culture believes in sons to carry on family lineage. Children, especially sons, are means of old age support to rural farmers. Rural children start to contribute to family income or family welfare from a young age whereas the cost of raising children is relatively low. And the flow of wealth is generally considered in favor of parents. Because level of child mortality is still high in rural areas, farmers would want to have more children to ensure that enough survive to adulthood. Contraception failure is another cause of excessive fertility. Women who become accidentally pregnant when contraceptive methods are used would find it an excuse to have the child. The implication of contraceptive failure to fertility should not be ignored. It was estimated that with 85-90% contraceptive effectiveness, a women would have 1.2-2.4 accidental pregnancies in her life time. The difference in the acceptance of the current government population policy between urban and rural areas suggests that it is important to produce political, economic, and cultural changes which subsequently induce changes in fertility. Development of an education system and introduction of means of old age support in rural areas would be the necessary steps to achieve this goal.

  4. Stationary populations with below-replacement fertility

    Directory of Open Access Journals (Sweden)

    Carl Schmertmann

    2012-04-01

    Full Text Available BACKGROUND A population with sustained below-replacement fertility and constant immigration eventually becomes stationary. Stationary-through-immigration (SI populations have unusual age structures that depend on the distribution of immigrants' arrival ages. OBJECTIVE I summarize known formal relationships between the distribution of immigrants' entry ages and the long-run size and structure of SI populations. I clarify a previously published result about SI dependency ratios. RESULTS The long-run size and age structure of an SI population depend on the remaining life expectancies of arriving immigrants, but are also sensitive to the expected numbers of native children born after arrival. Numerical calculations with contemporary Austrian data show (1 contrary to previously published results, immigration flows need not be concentrated in early working ages in order to ensure low overall dependency, and (2 the SI dependency ratio is minimized when all immigrants are in their mid-30s.

  5. Population pressure and fertility in pre-transition Thailand.

    Science.gov (United States)

    VanLandingham, M; Hirschman, C

    2001-11-01

    Before the demographic transition in Thailand, fertility was high, but not uniformly so. As in other pre-transition settings, Thai fertility responded to pressures and opportunities created by socioeconomic structure and land availability. Drawing upon provincial data from the 1947 and 1960 censuses of Thailand, we find a strong 'frontier effect' on Thai fertility in the 1950s. Fertility was higher in sparsely settled frontier provinces and lower in provinces with higher population density relative to cultivatable land. This finding is robust and holds up with controls for agricultural employment, land quality, and the sex ratio (an indicator of sex-selective migration). The effect of population pressure lowers the likelihood of marriage and of marital fertility. The findings from Thailand are consistent with the research of Easterlin on the nineteenth century United States and with other pre-transition societies. We suggest how demographic transition theory might be broadened to include fertility dynamics in pre-transition societies.

  6. An Evaluation of the Pearsonian Type I Curve of Fertility for Aboriginal Populations in Canada, 1996 to 2001

    OpenAIRE

    Verma, Ravi B.P.; Loh, Shirley

    2008-01-01

    EnglishIn 2005, Statistics Canada published new projections of the Aboriginal populations (NorthAmerican Indians, Métis, and Inuit) in Canada, the provinces and territories from 2001 to2017. To derive the number of births in these projections, the age-specific fertility rates weresimulated by fitting the Pearsonian Type I curve using the projected fertility parameters: totalfertility rates, mean ages of fertility, and modal ages of fertility. For the base period 1996 to2001, the parameters we...

  7. Canadian Provincial Population Growth: Fertility, Migration, and Age Structure Effects

    Directory of Open Access Journals (Sweden)

    Barry Edmonston

    2009-12-01

    Full Text Available The effect of changes in rates of mortality, fertility, and migration depend not only on the age-specific patterns and levels of these rates, but on the age structure of the population. In order to remove the influences of the age structure and concentrate on the impact of the demographic rates themselves, a common practice is to analyze the influences of the rates for a standard age structure. This paper adapts the general approach of using a standard age structure to a stationary population equivalent (SPE model, and analyzes current population change, using the SPE model, for provinces of Canada. Below-replacement fertility levels are only partially offset by net immigration. The SPE model evidences the decrease in the eventual provincial populations brought about by the below replacement fertility. Out-migration for some provinces to other areas of Canada accentuates their eventual population decreases.

  8. Easterlin's fertility theory and population adjustment and regulation in rural China.

    Science.gov (United States)

    Li, J

    1997-01-01

    The author considers some approaches which could be used to solve China's rural population problems through integrating Easterlin's fertility theory and certain characteristics of changes in China's rural population fertility. American demographer R.A. Easterlin conceptualized the meaning of fertility revolution with consideration of the overall modernization process. His theory is described. However, both effective family planning policies and attention to the impact of non-policy factors upon fertility changes are needed to resolve China's rural population problems. Community development and women's participation in Luo Chuan and Yong Shou, Shaanxi Province; the establishment of a social security support system for the elderly in Shandong Province; collective economy and rural urbanization in Southern Jiangsu Province; and improving the quality of family planning technical services are discussed.

  9. Effect of education on marital fertility in four Muslim populations.

    Science.gov (United States)

    Ahmad, S

    1985-01-01

    A comprehensive review of literature using cross national and cross regional studies did not reveal any systematic relationship between edcuation and fertility. This analysis--based on data collected in the mid-70s as part of the World Fertility Survey program in 4 Moslem populations--Bangladesh, Java, Jordan, and Pakistan--shows an inconsistent effect of education on marital fertility. Respondents were currently married and in their 1st marriage. "Level of education" divided women into 3 groups: no education, 1-5 years, and 6+ years. An inverted U-shape relationship between female education and current fertility was noticeable in Bangladesh and Java; an inverse relationship was supported by data from Jordan and Pakistan. Cumulative fertility, after controlling for duration of marriage, was found to be inversely related to 6+ years of education of the women in 3 populations, the exception being Java, where women with 6+ years of education show higher fertility than their counterparts. Analysis of variance showed a significant effect of wife-husband education on number of children ever born in all populations, except Pakistan. Multiple classification analysis did not reveal an appreciable difference in number of children ever born among the wife-husband education groups in Bangladesh, but a significant difference was noticed in Java and Jordan. In Pakistan, the education categories showed similar levels of fertility. The differences in fertility or lack of it by wife-husband level of education in these 4 Moslem populations were, to a large extent, explained by the interplay between the duration of breast feeding and the current use of efficient contraceptive methods.

  10. Canadian Provincial Population Growth: Fertility, Migration, and Age Structure Effects

    Directory of Open Access Journals (Sweden)

    Edmonston, Barry

    2009-01-01

    Full Text Available AbstractThe effect of changes in rates of mortality, fertility, and migration depend not only on the age specific patterns and levels of these rates, but on the age structure of the population. In orderto remove the influences of the age structure and concentrate on the impact of the demographic rates themselves, a common practice is to analyze the influences of the rates for a standard age structure. This paper adapts the general approach of using a standard age structure to a stationary population equivalent (SPE model, and analyzes current population change, using the SPE model, for provinces of Canada. Below-replacement fertility levels are only partially offset by net immigration. The SPE model evidences the decrease in the eventual provincial populations brought about by the below replacement fertility. Out-migration for some provincesto other areas of Canada accentuates their eventual population decreases.RésuméLes effets des changements des taux de mortalité, fécondité, et de migration dépendent non seulement des modèles par âge et des niveaux de ces taux, mais aussi de la structure par âge de la population. Pour éliminer les influences de la structure par âge et se concentrer sur les effets des taux démographiques mêmes, une pratique courante est d’analyser les influences des taux par une structure par âge de norme. Cet article adapte l’approche générale de la structure parâge à un modèle de population stationnaire équivalente (PSE. Cet article analyse les changements de population, en utilisant le modèle de PSE, dans les provinces canadiennes. Le taux de fécondité inférieur au seuil de reproduction de la population n’est que légèrement compensé par l’immigration nette. Le modèle de PSE démontre le déclin des populations provinciales éventuelles causé par le taux de fécondité inférieur au seuil de reproduction de la population. Le taux d’émigration entre certaines provinces et reste du

  11. Population Development Programme. Reduction of fertility rate a major goal.

    Science.gov (United States)

    1992-07-01

    South Africa's development program has aimed to reduce total fertility to 2 children per woman by the year 2010. Since the program's inception, fertility declined from 4.6 to 4.1. White fertility over the last 4 years decreased from 2.1 to 1.7; Asian fertility declined from 2.8 to 2.3; Black fertility declined from 4.2 to 3.7. Black fertility was very low in the PWV area (2.6) and in metropolitan areas (3.2). High fertility was reflected in TBVC countries and self-governing areas (5.3). Teenage births among Whites have declined from 7.2% to 5.9%, and among Coloreds from 16% to 12.8%. Asian teenage childbearing declined from 10.9% to 8.2%, and Black teenage childbearing increased from 11.4% to 16.5%. The infant mortality rate declined for all races, and Blacks remained with the highest rate of 50/1000 live births. Literacy rates improved for Coloreds from 60% to 66% and for Blacks from 48% to 54%. Contraceptive usage was 65% among Whites, 59.2% among Coloreds, 60.2% among Asians, and 43.8% among Blacks. Awareness of population growth problems was 68% in rural and 82% in urban areas. The business sector will gain from becoming involved in development through a better trained work force, improved job satisfaction and less unrest, reduced absenteeism rates, improved trust between employer and employee, and more favorable socioeconomic conditions for business. Public health and reduction in sexually transmitted diseases would also improve. The business community has the opportunity to invest in a variety of development activities: to promote technical education through scholarships, public campaigns to promote the image of technical careers, and exchange of information with educators about business needs. Business might also provide employee training, women's training, employee involvement in decision making, and employee benefits such as preventive health services. Family planning could be integrated into training courses for employees and emphasize the small family

  12. Trends in fertility and intermarriage among immigrant populations in Western Europe as measures of integration.

    Science.gov (United States)

    Coleman, D A

    1994-01-01

    Demographic data on fertility and intermarriage are useful measures of integration and assimilation. This paper reviews trends in total fertility and intermarriage of foreign populations in Europe and compares them with the trends in fertility of the host population and the sending country. In almost all cases fertility has declined. The fertility of most European immigrant populations and of some West Indian and non-Muslim Asian populations has declined to a period level at or below that of the host society. Muslim populations from Turkey, North Africa and South Asia have shown the least decline. Intermarriage is proceeding faster than might be expected in immigrant populations which seemed in economic terms to be imperfectly integrated. Up to 40% of West Indians born in the UK, for example, appear to have white partners as do high proportions of young Maghrebians in France.

  13. Is Low Fertility Really a Problem? Population Aging, Dependency, and Consumption*

    Science.gov (United States)

    2015-01-01

    Longer lives and fertility far below the replacement level of 2.1 births per woman are leading to rapid population aging in many countries. Many observers are concerned that aging will adversely affect public finances and standards of living. Analysis of newly available National Transfer Accounts data for 40 countries shows that fertility well above replacement would typically be most beneficial for government budgets. However, fertility near replacement would be most beneficial for standards of living when the analysis includes the effects of age structure on families as well as governments. And fertility below replacement would maximize per capita consumption when the cost of providing capital for a growing labor force is taken into account. While low fertility will indeed challenge government programs and very low fertility undermines living standards, we find that moderately low fertility and population decline favor the broader material standard of living PMID:25301626

  14. The long-term effect of the timing of fertility decline on population size

    NARCIS (Netherlands)

    O'Neill, BC; Scherbov, S; Lutz, W

    1999-01-01

    Existing long-range population projections imply that the timing of the fertility transition has a relatively unimportant effect on long-term population size when compared with the impact of the level at which fertility is assumed eventually to stabilize. However, this note shows that the effect of

  15. The long-term effect of the timing of fertility decline on population size

    NARCIS (Netherlands)

    O'Neill, BC; Scherbov, S; Lutz, W

    1999-01-01

    Existing long-range population projections imply that the timing of the fertility transition has a relatively unimportant effect on long-term population size when compared with the impact of the level at which fertility is assumed eventually to stabilize. However, this note shows that the effect of

  16. Rural-urban differentials in marital fertility in four Muslim populations.

    Science.gov (United States)

    Ahmad, S

    1985-04-01

    An analysis based on data collected as a part of the World Fertility Survey program in 4 Muslim populations Bangladesh, Java, Jordan and Pakistan does not show a consistent pattern in rural-urban differentials in marital fertility. While no significant diiferential in current fertility by place of current residence is noticeable in Bangladesh and Pakistan, urban women in Jordan showed lower fertility than their rural counterparts. Cumulative fertility, when controlled for duration of marriage, was found to be higher in urban than in rural areas of Bangladesh and Pakistan, but no clear pattern emerged in Jordan. In Java, both current and cumulative fertility were higher in urban than in rural areas; urban women who had spent their childhood and were brought up in the urban environment showed, in most instances, higher fertility than the other residence groups. (author's modified

  17. Genetic and phenotypic trends of fertility traits for Holstein dairy population in warm and temperate climate

    Directory of Open Access Journals (Sweden)

    Rabie Rahbar

    2016-04-01

    Full Text Available The main objective of this study was to investigate genetic and phenotypic trends for fertility traits in Holstein dairy population under warm and temperate climate. Fertility traits were: success in first service, gestation length, number of inseminations, insemination outcome, calving interval, calving birth weight and days open. The edited data set included up to 23,402 records from 9,486 cows. The mean and standard deviation for fertility traits were 0.32 ± 0.003, 278.2 ± 5.58, 2.73 ± 1.94,0.31 ± 0.001, 415.99 ± 79.62, 40.4 ± 6.08 and 140.36 ± 76.16 for success in first service, gestation length, number of inseminations, insemination outcome, calving interval, calving birth weight and days open, respectively. In general, there were decreasing genetic trends for all traits over the years. On the other hand, there were decreasing phenotypic trend for days open, calving interval, gestation length, number of inseminations and calving birth weight, but estimates of phenotypic trends were positive for success in first service and insemination outcome over the years. It was concluded decreased trend for days open, calving interval, gestation length, number of inseminations and calving birth weight and increased trend for success in first service and insemination outcome traits over time indicated that Holstein dairy producers in warm and temperate climate were successful in managing and improving in nutrition during 1999 to 2013.

  18. Natality, fertility and marriage status in Sepik River population of New Guinea.

    Science.gov (United States)

    Sturt, R J; Sturt, A E

    1974-12-01

    The characteristics of a defined population of 16 villages with 3,500 people in the Sepik District of Papua, New Guinea from January 1973 to December 1969 are provided as part of a large longitudinal survey planned to cover a full generation in order to determine the effect on health of contact from a Western civilization with a previousl y isolated Melanesian society. Study results are organized into 2 parts-the first part dealing with live births, stillbirths, fertility, maternal age and age-parity analysis, and the second part presenting findings on social factors such as birth interval, illegitimate births, adoption, widowhood, polygeny and divorce. Study results included the following information: 1) The birth rate was 35 per 1,000. A decrease of 50% in the infant mortality rate during the period of study apparently caused a decline in the birth rate; 2) Fertility was relatively low and substantially less than the biological potential. Late marriage, consequent late age for first children (23), and maintenance of a rigid birth interval (a mean of 3.3 years) accounted for low fertility; 3) A birth interval of less than 1.5 years is met with severe disapproval unless it follows the early death of the previous child; 4) Children are highly valued; illegitimate children are readily abosorbed into the extended family and children are freely adopted from one family to another. The "true" divorce rate (excluding unconsummated arranged marriages) was extremely low.

  19. Ecological feedbacks can reduce population-level efficacy of wildlife fertility control

    Science.gov (United States)

    Ransom, Jason I.; Powers, Jenny G.; Hobbs, N. Thompson; Baker, Dan L.

    2014-01-01

    1. Anthropogenic stress on natural systems, particularly the fragmentation of landscapes and the extirpation of predators from food webs, has intensified the need to regulate abundance of wildlife populations with management. Controlling population growth using fertility control has been considered for almost four decades, but nearly all research has focused on understanding effects of fertility control agents on individual animals. Questions about the efficacy of fertility control as a way to control populations remain largely unanswered. 2. Collateral consequences of contraception can produce unexpected changes in birth rates, survival, immigration and emigration that may reduce the effectiveness of regulating animal abundance. The magnitude and frequency of such effects vary with species-specific social and reproductive systems, as well as connectivity of populations. Developing models that incorporate static demographic parameters from populations not controlled by contraception may bias predictions of fertility control efficacy. 3. Many population-level studies demonstrate that changes in survival and immigration induced by fertility control can compensate for the reduction in births caused by contraception. The most successful cases of regulating populations using fertility control come from applications of contraceptives to small, closed populations of gregarious and easily accessed species. 4. Fertility control can result in artificial selection pressures on the population and may lead to long-term unintentional genetic consequences. The magnitude of such selection is dependent on individual heritability and behavioural traits, as well as environmental variation. 5. Synthesis and applications. Understanding species' life-history strategies, biology, behavioural ecology and ecological context is critical to developing realistic expectations of regulating populations using fertility control. Before time, effort and funding are invested in wildlife

  20. Population differences in self-fertility in the "self-incompatible" milkweed Asclepias exaltata (Asclepiadaceae).

    Science.gov (United States)

    Lipow, S R; Broyles, S B; Wyatt, R

    1999-08-01

    Individual plants of Asclepias exaltata (Asclepiadaceae) typically express an unusual self-incompatibility system under single-gene control. Hand-pollinations performed in six natural populations detected occasional self-fertile plants. The frequency of self-fertile individuals ranged from 0 to 34.0% and differed significantly among populations. Self-fertility appears to be under genetic control, as the ability of most plants (80.0 %) to set fruit following self-pollinations was identical under natural and greenhouse conditions. Seed- and fruit-set, however, were significantly lower from self- vs. cross-pollinations. Allozyme analysis of the population with the highest frequency of self-fertility revealed that adult plants were not significantly inbred. Finally, fruit-set following within-population cross-pollinations did not differ from that following wide, between-population cross-pollinations.

  1. Fertility and Child Mortality: Issues in the Demographic Transition of a Migrant Population.

    Science.gov (United States)

    Ben-Porath, Yoram

    This paper reviews issues pertaining to the relationship between child mortality and fertility and examines the fertility-mortality relationship of women who emigrated to Israel from various countries in Asia, Africa, and Europe and continued child bearing in Israel. Data from the 1961 Israel census of population is used. Among issues addressed in…

  2. Effects of fertilization on population density and productivity of herbaceous plants in desert steppe

    Institute of Scientific and Technical Information of China (English)

    JieQiong Su; XinRong Li; HaoTian Yang

    2014-01-01

    In order to investigate the impacts of fertilization on population density and productivity on herbaceous plants in desert steppe, nitrogen (N), phosphorus (P), and N-P addition experiments were performed. Each fertilizer treatment included four addition levels, i.e., 0, 5, 10, and 20 g/m2. The results indicated that population density decreased as fertilization levels increased regardless of the sort of fertilizer. More specifically, total density as well as density of Artemisia capillaris, Al-lium polyrhizum, and Enneapogon brachystachyus decreased significantly in 20 g/m2 treated plots, as compared with the control plots. Fertilization effects on aboveground and root biomasses were extremely similar to that found in population density; that is, both total aboveground biomass and aboveground biomasses for A. capillaris, A. polyrhizum, and E. brachystachyus were negatively correlated with increasing fertilization levels, with all determination coefficients (R2) greater than 0.80. Therefore, in the case of desert regions (annual precipitation <180 mm), fertilization would inhibit population density and productivity of herbaceous plants.

  3. Socio-economic fertility theories and their relevance to population policy.

    Science.gov (United States)

    Leibenstein, H

    1974-01-01

    A theory of fertility is necessary to assess the justification for family planning and to understand the effectiveness of the programs. 3 possibilities for uses of a theory of fertility are discussed: 1) assessment of population projections, 2) indications of what can be expected from family planning, and 3) assessment of population control projects. Birthrates are high, but fertility rates in developing countries are between 40% and 60% below the maximum possible. Social and cultural elements and economic incentives and constraints play a role in keeping the birthrates high. Economic development is frequently accompanied by a drop in fertility, but economic development implies other simultaneous changes which influence fertility rates. Gary Becker's fertility theory holds that with higher income people would purchase more children, the people behaving as they would in purchasing consumer durables. However, higher income groups frequently have fewer children. Becker says that higher income families want high-quality children who are more expensive. A pure economic theory does not explain all of the fertility variations; it is necessary to take account of the socioeconomic processes that result from economic development. Family planning policies that influence people's motivations should be developed.

  4. Fertility rates and future population trends: will Europe's birth rate recover or continue to decline?

    Science.gov (United States)

    Lutz, Wolfgang

    2006-02-01

    Europe has long completed its demographic transition from high birth and death rates to low birth and death rates. But the demographic transition paradigm that has been very useful for explaining global demographic trends during the 20th century and that still has strong predictive power when it comes to projecting future trends in countries that still have high fertility, has nothing to say about the future of fertility in Europe. The currently popular notion of a 'second demographic transition' is a useful way to describe a bundle of behavioural and normative changes that recently happened in Europe, but it has no predictive power. The social sciences have not yet come up with a useful theory to predict the future fertility level of post-demographic transition societies. We even do not know whether the trend will be up or down. Given the lack of a predictive theory, this paper will try to do two things: (i) Summarize different substantive arguments that would either suggest the assumption of a recovery of fertility rates in Europe or alternatively, imply further declines. (ii) Convert this discussion of the uncertainty of future fertility trends into probabilistic population projections for Europe, thus highlighting the implications of alternative fertility levels over the coming years. We will also discuss trade-offs between fertility and immigration, and the phenomenon that Europe now has entered a period of negative momentum of population growth.

  5. The Missing Children: Mortality and Fertility in a Southeast Asian Refugee Population.

    Science.gov (United States)

    Gordon, Linda W.

    1989-01-01

    Presents the age-sex structures of refugee populations arriving in the United States from Cambodia, Laos, and Vietnam from 1975 through 1986. Differences in the composition of these young populations reflect varying flight and resettlement experiences and changing factors influencing migration. High fertility rates predict a generation of rapid…

  6. Effects of fertilizers on soil’s microbial growth and populations: a review

    Directory of Open Access Journals (Sweden)

    Ojo OI

    2015-07-01

    Full Text Available Soil nutrients availability and decomposition of organic matter depends on microorganism but there are little available literatures on the possible effects of nutrients fixing chemicals and substances on the survival and population distribution of various microbes. Also, because of importance of organic and inorganic fertilizers to increase the soil microorganisms needed for the growth of plants there is need for comprehensive review of existing literature on the subject. This paper reviewed the effects of fertilizers on soil’s microbial growth and populations in available literatures. Various studies agreed that low microbe population due to lack of organic matter can be easily rectified by amending the soil with fertilizers and organic matter and allowing time for microbial growth therefore jump-starting the reproduction of microbes by adding beneficial microbes along with organic matter. Microbe improves soil structure by the humus they create while digesting organic matter and also help in nitrogen fixing.

  7. FERTILITY VARIATION AND EFFECTIVE POPULATION SIZE IN A TEAK CLONAL SEED ORCHARD

    Directory of Open Access Journals (Sweden)

    Sumardi Sumardi

    2011-06-01

    Full Text Available A 27 year old  clonal seed orchard of teak (Tectona grandis L.f in Padangan, East Java comprising 24 clones, was evaluated for fertility, offspring diversity, and genetic drift. Flower and fruit productions were used to assess clone fertility in the orchard. Fertility variation measured as ‘sibling coefficient’ was found to be 1,62, having high genetic diversity (0,97 and low coancestry (0,03. The clones varied in fertility in which,  25 % of the most fertile clones in the orchard contributed to 47,5 % of flower and fruit yields. Effective population size in the orchard was 15, indicating that 15 of the clones contributed effectively to seed yield. Separating on the amounts of seeds that can be collected, individual collection, and proportional mixing of seed per clone might be useful in restricting over representation of highly reproductive clones thereby increasing genetic diversity in the seed crop. Another way to improve seed yield in the orchard is by increasing the effective population size. Thinning or prunning on highly reproductive clones might be useful in increasing effective population size.

  8. Overlapping chromosomal regions for fertility traits and production traits in the Danish Holstein population

    DEFF Research Database (Denmark)

    Höglund, Johanna Karolina; Buitenhuis, A J; Guldbrandtsen, B

    2009-01-01

    , it is of interest to validate which of the subtraits are affected by the QTL. Phenotypic and marker data were collected from 34 grandsire families from the Danish Holstein population. First, the trait data for "fertility treatments" were separated into their underlying subtraits: uterine infections, antibiotics...

  9. Computer-assisted semen analysis parameters as predictors for fertility of men from the general population

    DEFF Research Database (Denmark)

    Larsen, L; Scheike, Thomas Harder; Jensen, Tina Kold;

    2000-01-01

    The predictive value of sperm motility parameters obtained by computer-assisted semen analysis (CASA) was evaluated for the fertility of men from general population. In a prospective study with couples stopping use of contraception in order to try to conceive, CASA was performed on semen samples...

  10. Economic benefit of fertility control in wild horse populations

    Science.gov (United States)

    Bartholow, J.

    2007-01-01

    I projected costs for several contraceptive treatments that could be used by the Bureau of Land Management (BLM) to manage 4 wild horse (Equus caballus) populations. Potential management alternatives included existing roundup and selective removal methods combined with contraceptives of different duration and effectiveness. I projected costs for a 20-year economic life using the WinEquus?? wild horse population model and state-by-state cost estimates reflecting BLM's operational expenses. Findings revealed that 1) currently available 2-year contraceptives in most situations are capable of reducing variable operating costs by 15%, 2) experimental 3-year contraceptives may be capable of reducing costs by 18%, and 3) combining contraceptives with modest changes to herd sex ratio (e.g., 55-60% M) could trim costs by 30%. Predicted savings can increase when contraception is applied in conjunction with a removal policy that targets horses aged 0-4 years instead of 0-5 years. However, reductions in herd size result in greater variation in annual operating expenses. Because the horse program's variable operating costs make up about half of the total program costs (which include other fixed costs), contraceptive application and management can only reduce total costs by 14%, saving about $6.1 million per year. None of the contraceptive options I examined eliminated the need for long-term holding facilities over the 20-year period simulated, but the number of horses held may be reduced by about 17% with contraceptive treatment. Cost estimates were most sensitive to the oldest age adoptable and per-day holding costs. The BLM will experience significant cost savings as carefully designed contraceptive programs become widespread in the wild horse herds it manages.

  11. Impact of cotton planting date and nitrogen fertilization on Bemisia argentifolii populations

    Institute of Scientific and Technical Information of China (English)

    JIAN-LONGBI; DONG-MEILIN; KEH-SHENLII; NICKC.TOSCANO

    2005-01-01

    The silverleaf whitefly (Bemisia argentifolii Bellows and Perring) is a widely distributed pest of cotton (Gossypium hirsutum L.) and the population levels may be affected by rates of nitrogen fertilization and planting date. Field experiments were conducted to investigate the impact of cotton planting date and nitrogen fertilization on silverleaf whitefly population dynamics. Cotton was planted on 26 April and 8 June, for the early and late plantings, respectively. Nitrogen treatments consisted of soil applications of 0, 112, 168 and 224 kg of nitrogen per hectare. The population levels of adult whiteflies were much higher on early-planted cotton than on late planting. Also, increased numbers of adult whiteflies on both early and late plantings occurred with increasing amounts of applied nitrogen.Applied nitrogen increased seed cotton yields of early plantings but had no effect on the yields of late plantings.

  12. Hindu-Muslim differentials in fertility and population growth in India: role of proximate variables.

    Science.gov (United States)

    Balasubramanian, K

    1984-09-01

    In India, Hindu and Muslim differentials in fertility were examined using census data and the findings of 11 surveys. An explanation of the fertility differences was offered. The proportion of Muslims in the population increased and the proportion of Hindus decreased, both before and after partition of the country. After partition, and between 1951-71, the proportion of Muslims increased from 9.9%-11.2% while the proportion of Hindus decreased from 84.9%-82.7%. An examination of mortality and migration data suggests that these proportional changes cannot be attributed to differences in migration or mortality; therefore, they must be due to differences in fertility. Census and survey data provide considerable evidence that fertility is higher among Muslims than among Hindus. According to the 1971 census data, the total marital fertility rate for Muslim women was 11% higher in urban areas and 20% higher in rural areas than the rate for Hindus. Even when education was controlled, the Muslim rate remained higher. The findings of 11 demographic surveys consistently revealed higher fertility rates for Muslims compared to Hindus. Several studies demonstrated that these differences narrowed but remained significant when education and socioeconomic factors were controlled. Investigators generally offer 1 of 3 hypotheses to explain the differences. The 1st hypothesis attributes the fertility differences to differences in the background or socioeconomic characteristics of the 2 populations. This explanation is not supported by studies which have introduced socioeconomic controls. The 2nd hypothesis states that minority status itself is a sufficient cause of high fertility. There is considerable evidence with which to refute this hypothesis. For example, in predominantly Muslim countries, Hindu minorities tend to have lower fertility than Muslims. The 3rd hypothesis attributed the fertility differences to religious beliefs concerning reproduction. Both Islam and Hinduism are

  13. Population ecology of feral horses in an era of fertility control management

    Science.gov (United States)

    Ransom, J.I.

    2012-01-01

    Management of wildlife often requires intervention to regulate growth of populations that would otherwise become overabundant. Controlling fecundity using contraceptives has become an increasingly popular tool for attempting to manage locally overabundant wildlife species, but the population-level effects of such applications are largely unknown. Contraceptive treatments can produce unexpected feedbacks that act on births, survival, immigration, and emigration. Such feedbacks may considerably influence our ability to regulate populations using fertility control. I followed feral horses (Equus caballus) in three intensively managed populations to assess longitudinal treatment effects on demography. The transient contraceptive porcine zona pellucida (PZP) produced longer duration of infertility than intended. Repeated PZP vaccinations of females extended the duration of infertility far beyond the targeted management period, with time to first post-treatment parturition increasing 411days for every annual inoculation received. When these animals did conceive and give birth, parturition was later in the year and temporally asynchronous with forage abundance. An average of 30% (range=11–77%) of females were contracepted annually during the treatment period in all three populations and apparent annual population growth rate was 4–9% lower in the post-treatment years as compared to pretreatment years. Population growth was positive, however, and increased steadily every year that a management removal did not occur. The observed number of births was 33% fewer than the expected number of births, based on number of treated females, individual efficacy of treatment, and number of untreated females and their age-specific fecundity rates. Only half of this difference was explained by the apparent residual effect of treatment. Birth rate in the youngest untreated females (age 2–5 years old) was reduced in years when their conspecifics were treated, enhancing the effects of

  14. Conventional semen parameters and DNA fragmentation in relation to fertility status in a Greek population.

    Science.gov (United States)

    Evgeni, Evangelini; Lymberopoulos, George; Gazouli, Maria; Asimakopoulos, Byron

    2015-05-01

    Our study aimed to investigate the possible correlations between conventional seminal parameters and DNA fragmentation in specific groups of Greek men, selected in relation to their fertility history and to verify the validity of the recent WHO reference values for the basic semen analysis in this population. A total of 770 subject data were evaluated in three distinct groups: fertile men with children naturally conceived within one year of unprotected intercourse (n=78), subfertile men, having achieved pregnancies either naturally or by Assisted Reproduction Techniques, not resulting in live births (n=153) and infertile men, failing to produce either pregnancies or children (n=539). Semen volume, sperm concentration, total count, rapid and total progressive motility and morphology were evaluated following the World Health Organization (2010) methods. DNA fragmentation was assessed by the Sperm Chromatin Dispersion assay. The 5th percentile, as well as the 95% confidence intervals (CI) for each parameter, were calculated by the method of bootstrapping. Statistical correlations between the examined parameters were sought using the Spearman R test (pDNA fragmentation and sperm concentration, total count, progressive motility (rapid and total) and normal morphology in subfertile and infertile men (pDNA fragmentation in our group of fertile men. Concordance was established between the reference limits issued by the WHO 2010 for the basic semen parameters and semen quality of fertile men in the studied population. The variability of correlations established between DNA fragmentation and the conventional seminal profile in relation to fertility status indicates that they are independent attributes of semen quality, justifying the assessment of both during a comprehensive evaluation of male infertility. Moreover, the WHO 2010 reference limits were found adequately descriptive of seminal normality in Greek men. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  15. An Evaluation of the Pearsonian Type I Curve of Fertility for Aboriginal Populations in Canada, 1996 to 2001

    Directory of Open Access Journals (Sweden)

    Verma, Ravi B.P.

    2008-01-01

    Full Text Available EnglishIn 2005, Statistics Canada published new projections of the Aboriginal populations (NorthAmerican Indians, Métis, and Inuit in Canada, the provinces and territories from 2001 to2017. To derive the number of births in these projections, the age-specific fertility rates weresimulated by fitting the Pearsonian Type I curve using the projected fertility parameters: totalfertility rates, mean ages of fertility, and modal ages of fertility. For the base period 1996 to2001, the parameters were estimated from the age-specific fertility rates derived from the 2001Census, using the “own-children method.” This paper evaluates the goodness of fit betweenthe age-specific fertility rates developed by the Type I curve and the estimated age-specificfertility rates for Aboriginal identity groups for the period 1996 to 2001 for Canada and forhigh and low fertility regions. Tests of validity of the Type I curve indicate that this method isappropriate for estimating/projecting the number of births for the Aboriginal populations.Key Words: Aboriginal populations, North American Indians, Métis, Inuit, own-childrenmethod, Pearsonian type I curve.FrenchEn 2005, Statistique Canada publiait de nouvelles projections des populations autochtones(Indiens de l’Amérique du Nord, Métis et Inuit au Canada, les provinces et les territoires de2001 à 2017. Afin de calculer le nombre de naissances dans ces projections, les taux de féconditépar âge ont été simulés en ajustant la courbe de Type I de Pearson selon les paramètresde fécondité projetés: l’indice synthétique de fécondité, l’âge moyen à l’accouchement et l’âgemodal à l’accouchement. Pour la période de base de 1996 à 2001, ces paramètres ont étéestimés selon les taux de fécondité par âge générés par la méthode du « décompte des enfantsau foyer » avec les données des enfants âgés de 0 à 4 ans et les femmes dans le groupe d’âgede 15 à 49 ans provenant du

  16. Fertility rates and perinatal outcomes of adolescent pregnancies: a retrospective population-based study

    Directory of Open Access Journals (Sweden)

    Maria de Lourdes de Souza

    Full Text Available ABSTRACT Objective: analyze trends in fertility rates and associations with perinatal outcomes for adolescents in Santa Catarina, Brazil. Methods: a population-based study covering 2006 to 2013 was carried out to evaluate associations between perinatal outcomes and age groups, using odds ratios, and Chi-squared tests. Results: differences in the fertility rate among female adolescents across regions and time period were observed, ranging from 40.9 to 72.0 per 1,000 in mothers aged 15-19 years. Adolescents had fewer prenatal care appointments than mothers ≥20 years, and a higher proportion had no partner. Mothers aged 15-19 years were more likely to experience preterm birth (OR:1.1; CI:1.08-1.13; p<0.001, have an infant with low birthweight (OR:1.1; CI:1.10-1.15; p<0.001 and low Apgar score at 5 minutes (OR:1.4; CI:1.34-1.45; p<0.001 than mothers ≥20 years, with the odds for adverse outcomes greater for those aged 10-14 years. Conclusion: this study provides evidence of fertility rates among adolescents remaining higher in regions of social and economic deprivation. Adolescent mothers and their infants more likely to experience adverse perinatal outcomes. Nurses, public health practitioners, health and social care professionals and educators need to work collaboratively to better target strategies for adolescents at greater risk; to help reduce fertility rates and improve outcomes.

  17. Below population replacement fertility rates:Can assisted reproductive technology (ART) help reverse the trend?

    Institute of Scientific and Technical Information of China (English)

    Eric Blyth

    2013-01-01

    Objective: This paper considers the potential contribution that assisted reproductive technology (ART) may make to population replenishment in countries that have experienced extended periods of below-population-replacement Total Fertility Rates (TFR), by focusing on the specific situation of Singapore, which has recorded ‘ultra-low’ TFRs for many years. Methods: The factors contributing to ultra-low TFRs in Singapore, the economic and social consequences of endemic below-population-replacement fertility rates and remedial measures initiated by the government are critically analysed, focussing specifically on the government’s subsided ART provisions of the ‘Marriage and Parenthood’ package. In addition the paper provides a close analysis of available contemporary data regarding ART and ART outcomes both in Singapore and internationally. Results: Despite limited public accessibility to data concerning ART outcomes in Singapore, it is possible to make some assessment of the potential contribution of publicly-funded ART provision and the possible extension of access to elective oocyte preservation to population replenishment. Conclusions: Subsidised ART can-at best-make a marginal contribution to government population policy.

  18. Very long range global population scenarios to 2300 and the implications of sustained low fertility

    Directory of Open Access Journals (Sweden)

    Stuart Basten

    2013-05-01

    Full Text Available BACKGROUND Depending on whether the global level of fertility is assumed to converge to the current European TFR (~1.5 or that of Southeast Asia or Central America (~2.5, global population will either decline to 2.3-2.9 billion by 2200 or increase to 33-37 billion, if mortality continues to decline. Furthermore, sizeable human populations exist where the voluntarily chosen ideal family size is heavily concentrated around one child per woman with TFRs as low as 0.6-0.8. However, the UN population projections to 2300 use a much narrower band of possible future TFRs. OBJECTIVE If the two-child norm is not necessarily the end-point of transition, what would be the consequences of the currently reported low fertility rates being sustained and becoming widespread? METHODS We present new projections for 13 IPCC world regions with scenarios calculated on the basis of regular cohort-component projections by age and sex in single-year time steps up to 2300, each based upon a much broader set of fertility assumptions than currently employed. We create three mortality scenarios based upon maximum life expectancies of 90, 100, and 110, as well as a series of 'special' scenarios. RESULTS Even under conditions of further substantial increases in life expectancy, world population size would decline significantly if the world in the longer run followed the current examples of Europe and East Asia. CONCLUSIONS In contrast to Malthusian disaster scenarios, our exercise illustrates the distinct possibility of significant population shrinking associated with increasing life expectancy and human well-being.

  19. Neural Population Dynamics Modeled by Mean-Field Graphs

    Science.gov (United States)

    Kozma, Robert; Puljic, Marko

    2011-09-01

    In this work we apply random graph theory approach to describe neural population dynamics. There are important advantages of using random graph theory approach in addition to ordinary and partial differential equations. The mathematical theory of large-scale random graphs provides an efficient tool to describe transitions between high- and low-dimensional spaces. Recent advances in studying neural correlates of higher cognition indicate the significance of sudden changes in space-time neurodynamics, which can be efficiently described as phase transitions in the neuropil medium. Phase transitions are rigorously defined mathematically on random graph sequences and they can be naturally generalized to a class of percolation processes called neuropercolation. In this work we employ mean-field graphs with given vertex degree distribution and edge strength distribution. We demonstrate the emergence of collective oscillations in the style of brains.

  20. Mean-field games with logistic population dynamics

    KAUST Repository

    Gomes, Diogo A.

    2013-12-01

    In its standard form, a mean-field game can be defined by coupled system of equations, a Hamilton-Jacobi equation for the value function of agents and a Fokker-Planck equation for the density of agents. Traditionally, the latter equation is adjoint to the linearization of the former. Since the Fokker-Planck equation models a population dynamic, we introduce natural features such as seeding and birth, and nonlinear death rates. In this paper we analyze a stationary meanfield game in one dimension, illustrating various techniques to obtain regularity of solutions in this class of systems. In particular we consider a logistic-type model for birth and death of the agents which is natural in problems where crowding affects the death rate of the agents. The introduction of these new terms requires a number of new ideas to obtain wellposedness. In a forthcoming publication we will address higher dimensional models. ©2013 IEEE.

  1. A Fertility Assessment of Infertile Men with Varicocele by Means of Doppler Ultrasound

    Institute of Scientific and Technical Information of China (English)

    王益鑫; 薄隽杰; 黄旭元; 钱宪明; 冷静; 韩银发

    1997-01-01

    The diameters of spermatic veins and blood reflux in sixty-two male patients with infertility caused by varicocele were assessed with Doppler ultrasound in this study. Scrotal thermograph, testes volume and semen analysis were also applied to analysis of these patients. Among sixty two patients, thirty-one received high ligation of internal spermatic vein. The results showed: 1. The diameter of spermatic veins was negatively correlated with fertility index and positively correlated with Doppler grading of blood reflux. 2. In operative patients, the effect of surgery was better in patients with blood reflux than in those without blood reflux. It was suggested the diameter of spermatie veins probably reflects the duration and serious degree of blood reflux in spermatic vein, and may be used for assessment of severi1ty of male infertility in combination with semen analysis.

  2. Personality and reproductive success in a high-fertility human population.

    Science.gov (United States)

    Alvergne, Alexandra; Jokela, Markus; Lummaa, Virpi

    2010-06-29

    The existence of interindividual differences in personality traits poses a challenge to evolutionary thinking. Although research on the ultimate consequences of personality differences in nonhuman animals has recently undergone a surge of interest, our understanding of whether and how personality influences reproductive decisions in humans has remained limited and informed primarily by modern societies with low mortality-fertility schedules. Taking an evolutionary approach, we use data from a contemporary polygynous high-fertility human population living in rural Senegal to investigate whether personality dimensions are associated with key life-history traits in humans, i.e., quantity and quality of offspring. We show that personality dimensions predict reproductive success differently in men and women in such societies and, in women, are associated with a trade-off between offspring quantity and quality. In women, neuroticism positively predicts the number of children, both between and within polygynous families. Furthermore, within the low social class, offspring quality (i.e., child nutritional status) decreases with a woman's neuroticism, indicating a reproductive trade-off between offspring quantity and quality. Consistent with this, maximal fitness is achieved by women at an intermediate neuroticism level. In men, extraversion was found to be a strong predictor of high social class and polygyny, with extraverted men producing more offspring than their introverted counterparts. These results have implications for the consideration of alternative adaptive hypotheses in the current debate on the maintenance of personality differences and the role of individual factors in fertility patterns in contemporary humans.

  3. [Recent population policy measures in Belgium, especially with respect to fertility].

    Science.gov (United States)

    Bosman, E

    1985-01-01

    Policy measures affecting fertility, recently adopted in Belgium, are reviewed. The author notes that although responsibility for population matters has been delegated to the respective language groups, the responsibility for family law, divorce, abortion, social security, taxation, and labor policy remains a national responsibility. There are currently no measures in these areas adopted primarily for demographic reasons. Differences between the approaches taken by the French- and Dutch-speaking communities are noted. The author suggests that the French-speaking community has focused on problems relating to contraception and abortion, and the Dutch-speaking community has emphasized social welfare and family policy

  4. Declines in fertility levels evident in Africa, notes UN Population Fund.

    Science.gov (United States)

    Ofosu-amaah, V

    1998-01-01

    This article reports on the UN Population Fund's (UNFPA) African regional meeting that was held in November 1997. The meeting was attended by an assortment of UNFPA representatives and program staff. This meeting followed up the 1994 Cairo International Conference on Population and Development (ICPD) and 1995 regional meetings on the 1994 Plan of Action. These prior meetings emphasized the link between population and development and the urgency of meeting the needs of individual women and men in a people-centered approach to development, rather than a target oriented one. The 1997 meeting reviewed the progress made toward achieving the goals of the 1994 plan of action by the UNFPA. UNFPA aims to decentralize operations, to play a role in emergency situations, to encourage South-to-South cooperation, to advocate for reproductive rights, and to promote gender equity and women's empowerment. The meeting discussed UNFPA's role in reproductive health, population and development strategies, and advocacy in detail. Participants agreed that there were signs of fertility decline in Africa. Countries are beginning to adopt a reproductive health and rights approach and to address female genital mutilation as a human and reproductive right's issue. Population policies are being changed to include ICPD goals. 32 countries adopted new programs in 1996 and 1997, that integrated the 1994 strategies and selectively focused on issues of concern. Partnerships confirm that population issues are becoming an agenda for all. The major challenge ahead is the mobilization of resources, while dealing with civil strife and political instability.

  5. ADVANCED STUDIES ON IMPROVING SHEEP FERTILITY BY USING ARTIFICIAL MEANS OF REPRODUCTION

    Directory of Open Access Journals (Sweden)

    Mostafa A.R. IBRAHIM

    2014-06-01

    Full Text Available Artificial insemination (AI in livestock is used to optimize reproduction efficiency. Compared to other semenpreservation methods, cryopreservation is an established industry used worldwide for performing AI. Adequateprotocols for semen collection and freezing and then for the use in the AI are set up for all the animal species. Insheep, AI with frozen-thawed semen resulted low fertility rate, which limits the practical application of thistechnique. Progressive sperm motility, sperm viability, sperm plasma membrane integrity and NAR weresignificantly (P < 0.05 higher for BIOX, MILK, and TEY extenders. Progressive motility increased significantly (p< 0.01 using licorice extract 10, 50 and 100 g/ml. Diluter type had a significant effect (p < 0.01 on sperm motility.The percentage of progressive motility in all extenders media containing LDL was also higher compared with 20%EY (control during dilution and equilibration stages. All extenders containing LDL reduced the percentages ofabnormalities after dilution as compared to control 20% egg yolk. The percentages of intact Acrosome in all otherextenders containing LDL were significantly higher than 20% egg yolk extender. The highest percentage of postthawprogressive motility was recorded in extender containing 20mm glutamine. After dilution and equilibration,supplementation of glutamine at concentration of 40 and 60mm caused a significant increase in plasma membraneintact compared with control and all other concentrations tested. No significant difference between the control andthe irradiated samples for viability However, the semen samples irradiated with 6.12 J/cm2 showed a slight increasein sperm progressive motility, viability, osmotic resistance, Acrosome and DNA integrity, respect to the semensamples irradiated at low energy doses and control semen samples. Cysteine effected on the ultra-structure of theram sperm cell within the freezing- thawing dynamics. The positive effect of Cysteine could

  6. Modeling controlled nutrient release from a population of polymer coated fertilizers: statistically based model for diffusion release.

    Science.gov (United States)

    Shaviv, Avi; Raban, Smadar; Zaidel, Elina

    2003-05-15

    A statistically based model for describing the release from a population of polymer coated controlled release fertilizer (CRF) granules by the diffusion mechanism was constructed. The model is based on a mathematical-mechanistic description of the release from a single granule of a coated CRF accounting for its complex and nonlinear nature. The large variation within populations of coated CRFs poses the need for a statistically based approach to integrate over the release from the individual granules within a given population for which the distribution and range of granule radii and coating thickness are known. The model was constructed and verified using experimentally determined parameters and release curves of polymer-coated CRFs. A sensitivity analysis indicated the importance of water permeability in controlling the lag period and that of solute permeability in governing the rate of linear release and the total duration of the release. Increasing the mean values of normally distributed granule radii or coating thickness, increases the lag period and the period of linear release. The variation of radii and coating thickness, within realistic ranges, affects the release only when the standard deviation is very large or when water permeability is reduced without affecting solute permeability. The model provides an effective tool for designing and improving agronomic and environmental effectiveness of polymer-coated CRFs.

  7. Optimal cut-off values and population means of waist circumference in different populations.

    Science.gov (United States)

    Wang, Zhiqiang; Ma, Jun; Si, Damin

    2010-12-01

    Abdominal obesity is a risk factor for cardiometabolic disease, and has become a major public health problem in the world. Waist circumference is generally used as a simple surrogate marker to define abdominal obesity for population screening. An increasing number of publications solely rely on the method that maximises sensitivity and specificity to define 'optimal' cut-off values. It is well documented that the optimal cut-off values of waist circumference vary across different ethnicities. However, it is not clear if the variation in cut-off values is a true biological phenomenon or an artifact of the method for identifying optimal cut-off points. The objective of the present review was to assess the relationship between optimal cut-offs and population waist circumference levels. Among sixty-one research papers, optimal cut-off values ranged from 65·5 to 101·2 cm for women and 72·5 to 103·0 cm for men. Reported optimal cut-off values were highly correlated with population means (correlation coefficient: 0·91 for men and 0·93 for women). Such a strong association was independent of waist circumference measurement techniques or the health outcomes (dyslipidaemia, hypertension or hyperglycaemia), and existed in some homogeneous populations such as the Chinese and Japanese. Our findings raised some concerns about applying the sensitivity and specificity approach to determine cut-off values. Further research is needed to understand whether the differences among populations in waist circumference were genetically or environmentally determined, and to understand whether using region-specific cut-off points can identify individuals with the same absolute risk levels of metabolic and cardiovascular outcomes among different populations.

  8. Effects of nationwide addition of selenium to fertilizers on foods, and animal and human health in Finland: From deficiency to optimal selenium status of the population.

    Science.gov (United States)

    Alfthan, Georg; Eurola, Merja; Ekholm, Päivi; Venäläinen, Eija-Riitta; Root, Tarja; Korkalainen, Katja; Hartikainen, Helinä; Salminen, Pirjo; Hietaniemi, Veli; Aspila, Pentti; Aro, Antti

    2015-01-01

    Despite different geological features the Nordic countries are generally selenium-poor areas. In each country various factors such as food importation and life-style determine the selenium (Se) intake. Due to an extremely low Se intake in the 1970s in Finland, 0.025 mg/day, an official decision was made in 1984 to supplement multinutrient fertilizers with Se in the chemical form of sodium selenate. Almost all fertilizers used in Finland since 1985 have contained Se. Currently all crop fertilizers contain 15 mg Se/kg. Finland is still the only country to take this country-wide measure. In a national monitoring programme, sampling of cereals, basic foodstuffs, feeds, fertilizers, soils, and human tissues has been carried out annually since 1985 by four governmental research organizations. Sampling of foods has been done four times per year and human blood has been obtained annually from the same (n=60) adults. The accuracy of analyses has been verified by annual interlaboratory quality control. During this programme the selenium concentration of spring cereals has increased on average 15-fold compared with the level before the Se fertilization. The mean increase in the Se concentration in beef, pork and milk was 6-, 2- and 3-fold. In terms of Se, organically grown foods of plant origin are generally comparable to products produced before the Se supplementation of fertilizers. Milk from organically fed cows is 50% lower in Se than the usual milk. The average dietary human intake increased from 0.04 mg Se/day/10 MJ in 1985 to a present plateau of 0.08 mg Se/day/10 MJ, which is well above the current nutrition recommendations. Foods of animal origin contribute over 70% of the total daily Se intake. The mean human plasma Se concentration increased from 0.89 μmol/L to a general level of 1.40 μmol/L that can be considered to be an optimal status. The absence of Se deficiency diseases and a reference population have made conclusions on the impact on human health difficult

  9. Fertility preservation in the male pediatric population: factors influencing the decision of parents and children.

    Science.gov (United States)

    Wyns, C; Collienne, C; Shenfield, F; Robert, A; Laurent, P; Roegiers, L; Brichard, B

    2015-09-01

    How can the decision process for fertility preservation (FP) in adolescents and prepubertal boys be improved based on patient and parent feelings about FP counseling? The content of information given to patients and parents and hope for future parenthood appeared to positively impact on the decision to preserve fertility in the pediatric population and, therefore, deserves special attention to improve FP care. A vast body of literature on adult cancer patients shows that reproductive capacity is a major quality-of-life issue. Patients also have a strong desire to be informed of available FP options with a view to future parenthood of their own genetic child, considering that parents were able to make an informed and voluntary decision for their prepubertal sons despite the heavy emotional burden at the time of diagnosis, there is so far very limited information on patient expectations regarding FP. A lack of awareness often equates to suboptimal care by oncologists and FP specialists, and poor access to FP, therefore improving knowledge and identifying the expectations of pediatric patients and their parents are crucial for optimizing multidisciplinary collaborative care pathways (MCCPs), including counseling and access to FP methods, in the youngest population. A questionnaire survey was posted to an eligible population between May 2005 and May 2013. A total of 348 prepubertal boys and adolescents aged 0-18 years, diagnosed with cancer in a university hospital setting, were eligible. Three different questionnaires for two age groups of children (parents were established based on information from focus groups. Questions were subsequently reviewed by the institutional ethics board before being sent. Of the 348 eligible patients, 44 died and 14 were lost to follow-up. Thus, 290 patients (77 aged 12-18 years and 213 aged children. FP acceptance rates were, respectively, 74 and 78.6% for boys aged parents appeared to positively impact on the decision to preserve

  10. Experimental and genetic analyses reveal that inbreeding depression declines with increased self-fertilization among populations of a coastal dune plant.

    Science.gov (United States)

    Dart, S; Eckert, C G

    2013-03-01

    Theory predicts that inbreeding depression (ID) should decline via purging in self-fertilizing populations. Yet, intraspecific comparisons between selfing and outcrossing populations are few and provide only mixed support for this key evolutionary process. We estimated ID for large-flowered (LF), predominantly outcrossing vs. small-flowered (SF), predominantly selfing populations of the dune endemic Camissoniopsis cheiranthifolia by comparing selfed and crossed progeny in glasshouse environments differing in soil moisture, and by comparing allozyme-based estimates of the proportion of seeds selfed and inbreeding coefficient of mature plants. Based on lifetime measures of dry mass and flower production, ID was stronger in nine LF populations [mean δ = 1-(fitness of selfed seed/fitness of outcrossed seed) = 0.39] than 16 SF populations (mean δ = 0.03). However, predispersal ID during seed maturation was not stronger for LF populations, and ID was not more pronounced under simulated drought, a pervasive stress in sand dune habitat. Genetic estimates of δ were also higher for four LF (δ = 1.23) than five SF (δ = 0.66) populations; however, broad confidence intervals around these estimates overlapped. These results are consistent with purging, but selective interference among loci may be required to maintain strong ID in partially selfing LF populations, and trade-offs between selfed and outcrossed fitness are likely required to maintain outcrossing in SF populations.

  11. Effects of in vitro fertilization and maternal characteristics on perinatal outcomes : a population-based study using siblings

    NARCIS (Netherlands)

    Seggers, Jorien; Pontesilli, Martina; Ravelli, Anita C. J.; Painter, Rebecca C.; Hadders-Algra, Mijna; Heineman, Maas Jan; Repping, Sjoerd; Mol, Ben Willem J.; Roseboom, Tessa J.; Ensing, Sabine

    Objective: To study birthweight in consecutively born sibling singletons conceived with and without in vitro fertilization (IVF) to disentangle the effects of maternal characteristics from those of the IVF treatment itself. Design: Population-based study. Setting: Not applicable. Patient(s):

  12. Fertility rates and perinatal outcomes of adolescent pregnancies: a retrospective population-based study.

    Science.gov (United States)

    Souza, Maria de Lourdes de; Lynn, Fiona Ann; Johnston, Linda; Tavares, Eduardo Cardoso Teixeira; Brüggemann, Odaléa Maria; Botelho, Lúcio José

    2017-04-06

    analyze trends in fertility rates and associations with perinatal outcomes for adolescents in Santa Catarina, Brazil. a population-based study covering 2006 to 2013 was carried out to evaluate associations between perinatal outcomes and age groups, using odds ratios, and Chi-squared tests. differences in the fertility rate among female adolescents across regions and time period were observed, ranging from 40.9 to 72.0 per 1,000 in mothers aged 15-19 years. Adolescents had fewer prenatal care appointments than mothers ≥20 years, and a higher proportion had no partner. Mothers aged 15-19 years were more likely to experience preterm birth (OR:1.1; CI:1.08-1.13; pprematuros (OR:1,1; IC:1,08-1,13; pprematuro (OR:1,1; IC:1,08-1,13; p<0,001), bebé con peso bajo al nacer (OR:1,1; IC:1,10-1,15; p<0,001) y puntuación de Apgar baja a los 5 minutes (OR:1,4; IC:1,34-1,45; p<0,001) fue superior para madres entre 15 y 19 años en comparación con madres ≥20 años, con mayores chances de resultados negativos para aquellas entre 10 y 14 años de edad. este estudio evidencia que las tasas de fertilidad entre las adolescentes siguen superiores en regiones de pobreza social y económica. Madres adolescentes y sus bebés tienen mayor probabilidad de efectos perinatales adversos. Enfermeros, trabajadores de salud pública, profesionales de salud y asistencia social y educadores deben colaborar para mejor dirigir estrategias a adolescentes con riesgo superior; para fines de ayudar a reducir las tasas de fertilidad y mejorar los resultados.

  13. Impaired Fertility Associated with Subclinical Hypothyroidism and Thyroid Autoimmunity: The Danish General Suburban Population Study

    Directory of Open Access Journals (Sweden)

    Anne-Dorthe Feldthusen

    2015-01-01

    Full Text Available Introduction. The aim of this study was to estimate the significance of TSH, thyroid peroxidase antibody (TPOAb, and mild (subclinical hypothyroidism in women from The Danish General Suburban Population Study (GESUS on the number of children born, the number of pregnancies, and the number of spontaneous abortions. Methods. Retrospective cross sectional study of 11254 women participating in GESUS. Data included biochemical measurements and a self-administrated questionnaire. Results. 6.7% had mild (subclinical hypothyroidism and 9.4% prevalent hypothyroidism. In women with mild hypothyroidism TPOAb was significantly elevated and age at first child was older compared to controls. TSH and TPOAb were negatively linearly associated with the number of children born and the number of pregnancies in the full cohort in age-adjusted and multiadjusted models. TSH or TPOAb was not associated with spontaneous abortions. Mild (subclinical hypothyroidism was associated with a risk of not having children and a risk of not getting pregnant in age-adjusted and multiadjusted models. Prevalent hypothyroidism was not associated with the number of children born, the number of pregnancies, or spontaneous abortions. Conclusion. Impaired fertility is associated with TSH, TPOAb, and mild (subclinical hypothyroidism in a Danish population of women.

  14. Impaired Fertility Associated with Subclinical Hypothyroidism and Thyroid Autoimmunity: The Danish General Suburban Population Study.

    Science.gov (United States)

    Feldthusen, Anne-Dorthe; Pedersen, Palle L; Larsen, Jacob; Toft Kristensen, Tina; Ellervik, Christina; Kvetny, Jan

    2015-01-01

    The aim of this study was to estimate the significance of TSH, thyroid peroxidase antibody (TPOAb), and mild (subclinical) hypothyroidism in women from The Danish General Suburban Population Study (GESUS) on the number of children born, the number of pregnancies, and the number of spontaneous abortions. Retrospective cross sectional study of 11254 women participating in GESUS. Data included biochemical measurements and a self-administrated questionnaire. 6.7% had mild (subclinical) hypothyroidism and 9.4% prevalent hypothyroidism. In women with mild hypothyroidism TPOAb was significantly elevated and age at first child was older compared to controls. TSH and TPOAb were negatively linearly associated with the number of children born and the number of pregnancies in the full cohort in age-adjusted and multiadjusted models. TSH or TPOAb was not associated with spontaneous abortions. Mild (subclinical) hypothyroidism was associated with a risk of not having children and a risk of not getting pregnant in age-adjusted and multiadjusted models. Prevalent hypothyroidism was not associated with the number of children born, the number of pregnancies, or spontaneous abortions. Impaired fertility is associated with TSH, TPOAb, and mild (subclinical) hypothyroidism in a Danish population of women.

  15. Nutritional status, fertility and factors associated with anaemia: a cross sectional study among a rural population of Muslim women in Assam, India.

    Science.gov (United States)

    Haloi, Anjali; Limbu, Dhruba Kumar

    2013-01-01

    In the present study an attempt has been made to report on the nutritional status of the Assamese Muslim women of Dadara and Agyathuri villages of the Kamrup district in Assam, India on their basis of body mass index (BMI) and haemoglobin (hb) content. Cross sectional data on 1034 women belonging to the age group of 19 years and above were collected following internationally accepted standards. The fertility of mothers by BMI range was found to be highest (6.50 (mean) +/- 0.14 (SE) and range being 1-11) amongst underweight mothers. The one-way analysis of variance (ANOVA) test of BMI and fertility shows significant relation between different BMI groups withp < 0.01. Highest haemoglobin levels were recorded in the age group of < or = 23 years with a mean of 11.61 +/- 0.06 g/dl, the range being 9.8-13.9 g/dl. Whereas lowest levels of haemoglobin were found in the age groups of 44+ years having a mean value of 10.26 +/- 0.04 g/dl and a range of 9.2-11.8 g/dl. The ANOVA analysis for haemoglobin content and corresponding fertility rates show significant difference between different hemoglobin levels with their live births at p < 0.01. The summary of ANOVA analysis for haemoglobin and BMI range shows the significant difference between groups i.e., normal, overweight and underweight. The t-value and F-ratio is 118.61 and 14068.42, respectively, which is significant at 1% probability. The authors conclude a general trend in the study population of women with high fertility having poor nutritional status. These findings might be important in formulating responsive health policies in an underdeveloped region.

  16. Long Term Population, City Size and Climate Trends in the Fertile Crescent: A First Approximation.

    Directory of Open Access Journals (Sweden)

    Dan Lawrence

    Full Text Available Over the last 8000 years the Fertile Crescent of the Near East has seen the emergence of urban agglomerations, small scale polities and large territorial empires, all of which had profound effects on settlement patterns. Computational approaches, including the use of remote sensing data, allow us to analyse these changes at unprecedented geographical and temporal scales. Here we employ these techniques to examine and compare long term trends in urbanisation, population and climate records. Maximum city size is used as a proxy for the intensity of urbanisation, whilst population trends are modelled from settlement densities in nine archaeological surveys conducted over the last 30 years across the region. These two measures are then compared with atmospheric moisture levels derived from multiple proxy analyses from two locations close to the study area, Soreq Cave in Israel and Lake Van in south-eastern Turkey, as well as wider literature. The earliest urban sites emerged during a period of relatively high atmospheric moisture levels and conform to a series of size thresholds. However, after the Early Bronze Age maximum urban size and population levels increase rapidly whilst atmospheric moisture declines. We argue that although the initial phase of urbanization may have been linked to climate conditions, we can see a definitive decoupling of climate and settlement patterns after 2000 BC. We relate this phenomenon to changes in socio-economic organisation and integration in large territorial empires. The complex relationships sustaining urban growth during this later period resulted in an increase in system fragility and ultimately impacted on the sustainability of cities in the long term.

  17. Cultural meanings of musculoskeletal diseases in Chile's Mapuche Population.

    Science.gov (United States)

    Alarcon, Ana M; Vidal, Aldo; Castro, Marcela

    2013-10-01

    Eight out of 10 Mapuche indigenous women have a musculoskeletal disorder (MSD) and do not seek early medical aid. To study both the cultural meanings and implications of MSD from the Mapuche worldview. Ethnographic study carried out from 2008 to 2011 on indigenous reserves in southern Chile. Sixty-four Mapuches participated in comprehensive interviews, which were transcribed and analyzed by the research team. Five cultural domains: (a) foro kutran/bone disease is the general denomination of MSD; (b) Re-Rume Kutran/progressive and incurable course, refers to the course of the disease; (c) Kalül fücha mawiza/body is an old tree, describes internal manifestations such as worn bones, dry body, weak blood, and spiritual weakness; (d) witrür tripai foro/deformation is the external manifestation of MSD; and (e) Reñma ka lof kutran/family and community suffering refers to the impact of MSD. The explanation of MSD is consistent with the integrated body-nature-spirit worldview of the Mapuche. To provide cultural nursing health care so that patients receive prompt diagnosis and care.

  18. Measuring the Impact of Antiretroviral Therapy Roll-Out on Population Level Fertility in Three African Countries.

    Directory of Open Access Journals (Sweden)

    Milly Marston

    Full Text Available UNAIDS official estimates of national HIV prevalence are based on trends observed in antenatal clinic surveillance, after adjustment for the reduced fertility of HIV positive women. Uptake of ART may impact on the fertility of HIV positive women, implying a need to re-estimate the adjustment factors used in these calculations. We analyse the effect of antiretroviral therapy (ART provision on population-level fertility in Southern and East Africa, comparing trends in HIV infected women against the secular trends observed in uninfected women.We used fertility data from four community-based demographic and HIV surveillance sites: Kisesa (Tanzania, Masaka and Rakai (Uganda and uMkhanyakude (South Africa. All births to women aged 15-44 years old were included in the analysis, classified by mother's age and HIV status at time of birth, and ART availability in the community. Calendar time period of data availability relative to ART Introduction varied across the sites, from 5 years prior to ART roll-out, to 9 years after. Calendar time was classified according to ART availability, grouped into pre ART, ART introduction (available in at least one health facility serving study site and ART available (available in all designated health facilities serving study site. We used Poisson regression to calculate age adjusted fertility rate ratios over time by HIV status, and investigated the interaction between ART period and HIV status to ascertain whether trends over time were different for HIV positive and negative women.Age-adjusted fertility rates declined significantly over time for HIV negative women in all four studies. However HIV positives either had no change in fertility (Masaka, Rakai or experienced a significant increase over the same period (Kisesa, uMkhanyakude. HIV positive fertility was significantly lower than negative in both the pre ART period (age adjusted fertility rate ratio (FRR range 0.51 95%CI 0.42-0.61 to 0.73 95%CI 0.64-0.83 and when

  19. Comparison of fertility indices in Iranian and non-Iranian populations under coverage of Ray's health houses, 1376

    Directory of Open Access Journals (Sweden)

    Sadeghi Pour Roudsari HR

    2000-06-01

    Full Text Available We studied fertility indices of Iranian and non-Iranian populations which were covered by 23 Rays health houses. This cross-sectional study aimed to prove the effect of increasing number of non-Iranian immigrants on health indices of the area covered by Tehran university of medical sciences and health services, consequently giving attention to specific health programs. The data collection method was census of permanent residents of the villages by means of vital horoscopes. 8494 of 27611 persons were non-Iranian. Dependency ratio and natural growth rate was 75%, 1.14% in Iranians and 98%, 1.74% in non-Iranians, respectively. Mortality in non-Iranians was 1.24 times more than Iranians. General fertility rate in Iranians was 60 and in non-Iranians was 110 live births in 1000 women of child bearing age. Total fertility rate in Iranians was 1.73 and in non-Iranians 3.27 neonates for each woman. Age-specific fertility rates were absolutely higher in non-Iranians. Gross eproductive rate was 0.87 in Iranians and 1.59 in non-Iranians. Mean number of girls born by a non-Iranian mother will be double times of an Iranian mother (P<0.01. Modern contraceptive methods coverage was 70% in Iranian couples and less than 40% in non-Iranian couples. 96.94% of Iranian deliveries and 70.9% of non-Iranian deliveries were safe (P<0.01.

  20. LOW MINERAL DENSITY OF A WEIGHT-BEARING BONE AMONG ADULT WOMEN IN A HIGH FERTILITY POPULATION

    Science.gov (United States)

    Stieglitz, Jonathan; Beheim, Bret A.; Trumble, Benjamin C.; Madimenos, Felicia C.; Kaplan, Hillard; Gurven, Michael

    2014-01-01

    Evolutionary theories of aging posit that greater reproductive effort causes somatic decline given a fundamental trade-off between investing energy in reproduction and repair. Few studies in high fertility human populations support this hypothesis, and problems of phenotypic correlation can obscure the expected trade-off between reproduction and somatic condition. This cross-sectional study investigates whether greater reproductive effort is associated with reduced calcaneal bone mineral density (BMD) among female Tsimane forager-farmers of lowland Bolivia. We also investigate whether female Tsimane BMD values are lower than sex- and age-matched US reference values, despite the fact that Tsimane engage in higher physical activity levels that can increase mechanical loading. To measure calcaneal BMD, quantitative ultrasonography was performed on 130 women (mean ± SD age = 36.6 ± 15.7, range = 15 – 75) that were recruited regardless of past or current reproductive status. Anthropometric and demographic data were collected during routine medical exams. As predicted, higher parity, short inter-birth interval, and earlier age at first birth are associated with reduced BMD among Tsimane women after adjusting for potential confounders. Population-level differences are apparent prior to the onset of reproduction, and age-related decline in BMD is greater among Tsimane compared to American women. Greater cumulative reproductive burden may lower calcaneal BMD individually and jointly with other lifestyle and heritable factors. Fitness impacts of kin transfers in adulthood may determine the value of investments in bone remodeling, and thus affect selection on age-profiles of bone mineral loss. PMID:25488367

  1. Fertilization variants effect in the incidence and populational fluctuation of the true bugs complex (Hemipterous: Pentatomidae in common bean

    Directory of Open Access Journals (Sweden)

    Yordanys Ramos González

    2016-03-01

    Full Text Available This work was done in the “Panchita Orchard” Township Quemado de Guines, province of Villa Clara from September 2010 to December 2011. Was to determine the effect of fertilization have some variations in behavior and incidence of associated pentatomid common bean. Varieties were planted two different colored heads (1 red and 1 white in random blocks on a Brown soil Carbonated Fluffy. The input of the first adults phenophase occurred in R2 and R3 peak in population with 28.8% of the Pentatomidae detected. In the two varieties studied, Rhizobium fertilization showed the best effects in reducing insect and the rate and degree of involvement, the opposite of what happened with the urea, which were equal to the control population levels, but higher affectations. The pentatomids presented similar preference for the two varieties since no differences in the parameters.

  2. 1. Fertility differentials by incidence of marriage and their reproductive wastage in a Muslim population from rural north-east India

    Directory of Open Access Journals (Sweden)

    Anjali Haloi

    2014-01-01

    Full Text Available :The study strives to assess the fertility differentials by women's present age, influence of incidence of marriage (whether once or more than once married /consanguineous or non-consanguineous marriage, their reproductive wastage and the effect of socio-economic factors on reproductive wastage of women in a rural Muslim population of North-East India. Data for the present study were collected on 1034 married women (15-49 years through structured schedule by cross sectional method and then presented in terms of percentage, mean, and standard error. Student's t-test and ANOVA test were also applied to see the significant difference. The multiple regression analysis was used to predict whether or not reproductive wastage depends on some other independent variables. . The present study reveals that mean live births (fertility are directly proportional to the advancement of age of women, which is probably due to the fact that higher number of pregnancies in older women results from a lack of education and antenatal care leading to concomitant miscarriages and stillbirths. Marriage among the Assamese Muslims was found to be very 'stable' as only 12 females (1.17% of all married individuals reportedly changed their mates. There are 23.73% women, whose marriage is consanguineous while 77.27% women have non-consanguineous marriage. In the former group, 38 (3.7% women have given birth to physically deformed children while not a single case of physically deformed children was reported among the mothers of the latter group. The frequency of reproductive wastage, of all the pregnancies considered in this study, was found to be 14.32%. Further the study shows that women's age, maternal education, type of family, household income and antenatal care are important factors in regulating the fertility and reproductive wastage of a population.

  3. Heritability and fitness correlates of personality in the Ache, a natural-fertility population in Paraguay.

    Directory of Open Access Journals (Sweden)

    Drew H Bailey

    Full Text Available The current study assessed the heritability of personality in a traditional natural-fertility population, the Ache of eastern Paraguay. Self-reports (n = 110 and other-reports (n = 66 on the commonly used Big Five Personality Inventory (i.e., extraversion, agreeableness, conscientiousness, neuroticism, openness were collected. Self-reports did not support the Five Factor Model developed with Western samples, and did not correlate with other-reports for three of the five measured personality factors. Heritability was assessed using factors that were consistent across self- and other-reports and factors assessed using other-reports that showed reliabilities similar to those found in Western samples. Analyses of these items in combination with a multi-generation pedigree (n = 2,132 revealed heritability estimates similar to those found in most Western samples, although we were not able to separately estimate the influence of the common environment on these traits. We also assessed relations between personality and reproductive success (RS, allowing for a test of several mechanisms that might be maintaining heritable variation in personality. Phenotypic analyses, based largely on other-reports, revealed that extraverted men had higher RS than other men, but no other dimensions of personality predicted RS in either sex. Mothers with more agreeable children had more children, and parents mated assortatively on personality. Of the evolutionary processes proposed to maintain variation in personality, assortative mating, selective neutrality, and temporal variation in selection pressures received the most support. However, the current study does not rule out other processes affecting the evolution and maintenance of individual differences in human personality.

  4. Heritability and fitness correlates of personality in the Ache, a natural-fertility population in Paraguay.

    Science.gov (United States)

    Bailey, Drew H; Walker, Robert S; Blomquist, Gregory E; Hill, Kim R; Hurtado, A Magdalena; Geary, David C

    2013-01-01

    The current study assessed the heritability of personality in a traditional natural-fertility population, the Ache of eastern Paraguay. Self-reports (n = 110) and other-reports (n = 66) on the commonly used Big Five Personality Inventory (i.e., extraversion, agreeableness, conscientiousness, neuroticism, openness) were collected. Self-reports did not support the Five Factor Model developed with Western samples, and did not correlate with other-reports for three of the five measured personality factors. Heritability was assessed using factors that were consistent across self- and other-reports and factors assessed using other-reports that showed reliabilities similar to those found in Western samples. Analyses of these items in combination with a multi-generation pedigree (n = 2,132) revealed heritability estimates similar to those found in most Western samples, although we were not able to separately estimate the influence of the common environment on these traits. We also assessed relations between personality and reproductive success (RS), allowing for a test of several mechanisms that might be maintaining heritable variation in personality. Phenotypic analyses, based largely on other-reports, revealed that extraverted men had higher RS than other men, but no other dimensions of personality predicted RS in either sex. Mothers with more agreeable children had more children, and parents mated assortatively on personality. Of the evolutionary processes proposed to maintain variation in personality, assortative mating, selective neutrality, and temporal variation in selection pressures received the most support. However, the current study does not rule out other processes affecting the evolution and maintenance of individual differences in human personality.

  5. [Effects of nitrogen fertilization on population dynamics and yield of high-yielding wheat and on alteration of soil nitrogen].

    Science.gov (United States)

    Ye, You-Liang; Wang, Gui-Liang; Zhu, Yun-Ji; Li, Huan-Huan; Huang, Yu-Fang

    2010-02-01

    Taking wheat varieties Yumai 49-198 (multi-spike phenotype) and Lankao Aizao 8 (large-spike phenotype) as test materials, field experiments were conducted at Wenxian and Lankao sites of Henan Province to study the effects of nitrogen fertilization on their population dynamics and yield and on the alteration of soil nitrogen. Five nitrogen application rates, i. e., 0, 90, 180, 270, and 360 N kg x hm(-2) were installed. The population amount of the two test varieties were all increased after emergence, reached the highest at jointing stage, and decreased afterwards. As for Yumai 49-198, its population amount had no significant differences at wintering and turning-green stages among the five nitrogen application rates and two experimental sites, but differed significantly after jointing stage with the nitrogen application rates. For Lankao Aizao 8, its population amount had no significant differences among the nitrogen application rates during whole growth period. The grain yield of the two varieties increased with the increase of nitrogen fertilization rate, but excessive nitrogen fertilization decreased the grain yield. Yumai 49-198 had the highest yield at 270 N kg x hm(-2), being 9523 and 9867 kg x hm(-2) at Wenxian and Lanako sites, respectively, while Lankao Aizao 8 had the highest yield at 180 N kg x hm(-2), being 9258 and 9832 kg x hm(-2) at Wenxian and Lanako sites, respectively. With the increase of nitrogen fertilization rate, soil nitrate N concentration and apparent nitrogen loss increased. At Wenxian and Lankao sites, the apparent soil nitrogen loss for Yumai 49-198 was 32.56% - 51.84% and - 16.7% - 42.6% of fertilized nitrogen, and that for Lankao Aizao 8 was 18.58% - 52.94% and - 11.5% - 45.8% of fertilized nitrogen, respectively. Considering the yield and environmental effect comprehensively, the nitrate N concentration in 0-90 cm soil layer in our case should not be exceeded 120 - 140 kg x hm(-2), and the maximal nitrogen application rate should not

  6. The Effect of Organic Fertilizers and Flowering Plants on Sheet-Web and Wolf Spider Populations (Araneae: Lycosidae and Linyphiidae) and Its Importance for Pest Control.

    Science.gov (United States)

    El-Nabawy, El-Said M; Tsuda, Katsuo; Sakamaki, Yositaka; Oda, Asahi; Ushijima, Yurie

    2016-01-01

    The main goal of this study was to identify the treatment that increases the populations of spiders, which are effective predators in agroecosystems. In 2013 and 2014 the experimental eggplant (Solanum melongena L.) field was two different treatments, organic fertilizers and chemical fertilizer treatment, and in 2014 we surrounded organic fertilizer plots with the flowering plants mealy cup sage (Salvia farinacea Benth.), spearmint (Mentha spicata L.), and basil (Ocimum basilicum L.). Analysis using repeated measures ANOVA revealed significant influences of fertilizer type on the numbers of linyphiid spiders and Collembola in 2013. In 2014, the numbers of Collembola, thrips, and lycosid and linyphiid spider were higher in organic fertilizer with flowering plants treatment comparing with the chemical fertilizer treatment. Moreover, the numbers of Henosepilachna vigintioctopunctata (F.) were significantly lower in the organic fertilizer with flowering plants treatment than in chemical fertilizers treatment. Finally, we expect that Thysanoptera and Collembola were important alternative prey for linyphiid and lycosid spiders and the use of organic fertilizer and flowering plants enhanced the density of these spiders, and may increase their effectiveness in suppressing the populations of H. vigintioctopunctata (F.).

  7. Comparison of age-related changes in anti-Müllerian hormone levels and other ovarian reserve tests between healthy fertile and infertile population.

    Science.gov (United States)

    Bozkurt, Banu; Erdem, Mehmet; Mutlu, Mehmet Firat; Erdem, Ahmet; Guler, Ismail; Mutlu, Ilknur; Oktem, Mesut

    2016-09-01

    In this study, we aimed to determine whether anti-Müllerian hormone (AMH) levels vary between fertile and infertile populations and compare them with basal follicle-stimulating hormone (FSH) levels and antral follicle count (AFC). This was a prospective study that included 177 primarily infertile patients who underwent IVF treatment and 162 healthy fertile patients admitted to our clinic for benign diseases. FSH and AMH levels and the AFC of the infertile and fertile populations were compared between the age categories age were evaluated. AFC and AMH levels did not differ between the fertile and infertile groups in all age categories. AMH was inversely correlated with age in both the fertile and infertile populations. However, AFC revealed a stronger correlation with age in both the fertile and infertile populations compared with basal FSH and AMH. Age was positively correlated with basal FSH and inversely correlated with AMH and AFC. In conclusion, there was no significant difference between the fertile and infertile populations in terms of AMH or AFC. The decrease in ovarian reserve in infertile patients is directly related to age, not infertility.

  8. The future fertility of mankind: effects on world population growth and migration.

    Science.gov (United States)

    Short, R V

    2001-01-01

    The world's population, currently just over 6 billion, is projected to increase to 9-10 billion by the year 2050. Most of this growth will occur in the developing countries of Asia, where there is an enormous unmet demand for contraception, while an increasing number of developed countries will have declining populations. The human immunodeficiency virus (HIV) pandemic will target developing countries, with India destined to become its new epicenter. By 2050, there may be 1 billion HIV-infected people in the world. The significant protective effect of male circumcision may spare Islamic countries, such as Pakistan, Bangladesh, Iran and Indonesia, from the worst effects of the pandemic. Australia will be increasingly threatened by the high rates of population growth of her Asian neighbours. This, coupled with political instability and sea-level rises as a consequence of global warming, will turn the present trickle of refugees from a variety of Asian countries seeking safe haven on our sparsely populated northern coastline into a veritable flood. There will come a time when we have neither the manpower, nor the means, nor even the moral right to intercept, detain or repatriate the thousands who will come in peace, in search of a better life. However, if Australia is to stabilize its future population at around 23 million, which seems highly desirable on ecological grounds, then the net immigration rate must be limited to approximately 50000 people per year. Because the final point of departure for all these refugees is Indonesia, it is essential that Australia maintains good relations with Indonesia, so that together we can attempt to manage the refugee problem. However, Indonesia's own population is destined to increase by 100 million in the next 50 years, which will only exacerbate the situation. Australia would be well advised to make a major increase in its paltry financial assistance to Indonesia's excellent family planning programmes, which are currently

  9. Regression toward the mean – a detection method for unknown population mean based on Mee and Chua's algorithm

    Directory of Open Access Journals (Sweden)

    Lüdtke Rainer

    2008-08-01

    Full Text Available Abstract Background Regression to the mean (RTM occurs in situations of repeated measurements when extreme values are followed by measurements in the same subjects that are closer to the mean of the basic population. In uncontrolled studies such changes are likely to be interpreted as a real treatment effect. Methods Several statistical approaches have been developed to analyse such situations, including the algorithm of Mee and Chua which assumes a known population mean μ. We extend this approach to a situation where μ is unknown and suggest to vary it systematically over a range of reasonable values. Using differential calculus we provide formulas to estimate the range of μ where treatment effects are likely to occur when RTM is present. Results We successfully applied our method to three real world examples denoting situations when (a no treatment effect can be confirmed regardless which μ is true, (b when a treatment effect must be assumed independent from the true μ and (c in the appraisal of results of uncontrolled studies. Conclusion Our method can be used to separate the wheat from the chaff in situations, when one has to interpret the results of uncontrolled studies. In meta-analysis, health-technology reports or systematic reviews this approach may be helpful to clarify the evidence given from uncontrolled observational studies.

  10. A Bayesian model for estimating population means using a link-tracing sampling design.

    Science.gov (United States)

    St Clair, Katherine; O'Connell, Daniel

    2012-03-01

    Link-tracing sampling designs can be used to study human populations that contain "hidden" groups who tend to be linked together by a common social trait. These links can be used to increase the sampling intensity of a hidden domain by tracing links from individuals selected in an initial wave of sampling to additional domain members. Chow and Thompson (2003, Survey Methodology 29, 197-205) derived a Bayesian model to estimate the size or proportion of individuals in the hidden population for certain link-tracing designs. We propose an addition to their model that will allow for the modeling of a quantitative response. We assess properties of our model using a constructed population and a real population of at-risk individuals, both of which contain two domains of hidden and nonhidden individuals. Our results show that our model can produce good point and interval estimates of the population mean and domain means when our population assumptions are satisfied.

  11. Two-Stage Sampling Procedures for Comparing Means When Population Distributions Are Non-Normal.

    Science.gov (United States)

    Luh, Wei-Ming; Olejnik, Stephen

    Two-stage sampling procedures for comparing two population means when variances are heterogeneous have been developed by D. G. Chapman (1950) and B. K. Ghosh (1975). Both procedures assume sampling from populations that are normally distributed. The present study reports on the effect that sampling from non-normal distributions has on Type I error…

  12. An alternative procedure for estimating the population mean in simple random sampling

    Directory of Open Access Journals (Sweden)

    Housila P. Singh

    2012-03-01

    Full Text Available This paper deals with the problem of estimating the finite population mean using auxiliary information in simple random sampling. Firstly we have suggested a correction to the mean squared error of the estimator proposed by Gupta and Shabbir [On improvement in estimating the population mean in simple random sampling. Jour. Appl. Statist. 35(5 (2008, pp. 559-566]. Later we have proposed a ratio type estimator and its properties are studied in simple random sampling. Numerically we have shown that the proposed class of estimators is more efficient than different known estimators including Gupta and Shabbir (2008 estimator.

  13. Personality and reproductive success in a high-fertility human population

    OpenAIRE

    Alvergne, A.; JOKELA, M; Lummaa, V

    2010-01-01

    The existence of interindividual differences in personality traits poses a challenge to evolutionary thinking. Although research on the ultimate consequences of personality differences in nonhuman animals has recently undergone a surge of interest, our understanding of whether and how personality influences reproductive decisions in humans has remained limited and informed primarily by modern societies with low mortality–fertility schedules. Taking an evolutionary approach, we use data from a...

  14. A demographic transition altered the strength of selection for fitness and age-specific survival and fertility in a 19th century American population.

    Science.gov (United States)

    Moorad, Jacob A

    2013-06-01

    Modernization has increased longevity and decreased fertility in many human populations, but it is not well understood how or to what extent these demographic transitions have altered patterns of natural selection. I integrate individual-based multivariate phenotypic selection approaches with evolutionary demographic methods to demonstrate how a demographic transition in 19th century female populations of Utah altered relationships between fitness and age-specific survival and fertility. Coincident with this demographic transition, natural selection for fitness, as measured by the opportunity for selection, increased by 13% to 20% over 65 years. Proportional contributions of age-specific survival to total selection (the complement to age-specific fertility) diminished from approximately one third to one seventh following a marked increase in infant survival. Despite dramatic reductions in age-specific fertility variance at all ages, the absolute magnitude of selection for fitness explained by age-specific fertility increased by approximately 45%. I show that increases in the adaptive potential of fertility traits followed directly from decreased population growth rates. These results suggest that this demographic transition has increased the adaptive potential of the Utah population, intensified selection for reproductive traits, and de-emphasized selection for survival-related traits. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

  15. A FAMILY OF ESTIMATORS FOR ESTIMATING POPULATION MEAN IN STRATIFIED SAMPLING UNDER NON-RESPONSE

    OpenAIRE

    Chaudhary, Manoj K.; RAJESH SINGH; Rakesh K. Shukla; MUKESH KUMAR; FLORENTIN SMARANDACHE

    2015-01-01

    Khoshnevisan et al. (2007) proposed a general family of estimators for population mean using known value of some population parameters in simple random sampling. The objective of this paper is to propose a family of combined-type estimators in stratified random sampling adapting the family of estimators proposed by Khoshnevisan et al. (2007) under non-response. The properties of proposed family have been discussed. We have also obtained the expressions for optimum sampl...

  16. A FAMILY OF ESTIMATORS FOR ESTIMATING POPULATION MEAN IN STRATIFIED SAMPLING UNDER NON-RESPONSE

    OpenAIRE

    Chaudhary, Manoj K.; Rajesh Singh; Rakesh K. Shukla; Mukesh Kumar; Florentin Smarandache

    2009-01-01

    Khoshnevisan et al. (2007) proposed a general family of estimators for population mean using known value of some population parameters in simple random sampling. The objective of this paper is to propose a family of combined-type estimators in stratified random sampling adapting the family of estimators proposed by Khoshnevisan et al. (2007) under non-response. The properties of proposed family have been discussed. We have also obtained the expressions for optimum sample sizes of the strata i...

  17. Estimation of finite population mean with known coefficient of variation of an auxiliary character

    Directory of Open Access Journals (Sweden)

    Housila P. Singh

    2007-10-01

    Full Text Available This paper deals with the problem of estimating population mean Y of the study variate y using information on population mean X and coefficient of variation Cx of an auxiliary character x. We have suggested an estimator for Y and its properties are studied in the context of single sampling. It is shown that the proposed estimator is more efficient than Sisodia and Dwivedi (1981 estimator and Pandey and Dubey (1988 estimator under some realistic conditions. An empirical study is carried out to examine the merits of the constructed estimator over others.

  18. A model to search for birth probabilities of mammal populations using fertility data

    Directory of Open Access Journals (Sweden)

    JR. Moreira

    Full Text Available A model was constructed to predict monthly birth probabilities using mammalian fertility data. We used a sample of 147 female capybaras (Hydrochoerus hydrochaeris hunted on a farm on Marajó Island, Brazil. In the model each month was treated as a multinomial with six cells representing the six possible reproductive states (five months gestation. A hypothesis test was carried out to see whether a cosine curve would fit the birth probabilities. The results offer no support for a seasonal component (F2,9 = 1.84, P = 0.21, whereas results from a direct census do (F3,23 = 87.29, P < 0.01. Some hunting techniques were biased towards killing pregnant females (χ(21= 7.2, P< 0.01, thereby spreading reproduction throughout the year (F2,9 = 1.84, P = 0.21. The model remained a powerful predictive tool to be used with mammalian fertility data as long as the data are not biased towards pregnant females.

  19. A population-based cohort study of the effect of Caesarean section on subsequent fertility.

    Science.gov (United States)

    Gurol-Urganci, I; Cromwell, D A; Mahmood, T A; van der Meulen, J H; Templeton, A

    2014-06-01

    Is there an association between Caesarean section and subsequent fertility? There is no or only a slight effect of Caesarean section on future fertility. Previous studies have reported that delivery by a Caesarean section is associated with fewer subsequent pregnancies and longer inter-pregnancy intervals. The interpretation of these findings is difficult because of significant weaknesses in study designs and analytical methods, notably the potential effect of the indication for Caesarean section on subsequent delivery. Retrospective cohort study of 1 047 644 first births to low-risk women using routinely collected, national administrative data of deliveries in English maternity units between 1 April 2000 and 31 March 2012. Primiparous women aged 15-40 years who had a singleton, term, live birth in the English National Health Service were included. Women with high-risk pregnancies involving placenta praevia, pre-eclampsia, eclampsia (gestational or pre-existing), hypertension or diabetes were excluded from the main analysis. Kaplan-Meier analyses and Cox proportional hazard models were used to assess the effect of mode of delivery on time to subsequent birth, adjusted for age, ethnicity, socio-economic deprivation and year of index delivery. Among low-risk primiparous women, 224 024 (21.4%) were delivered by Caesarean section. The Kaplan-Meier estimate of the subsequent birth rate at 10 years for the cohort was 74.7%. Compared with vaginal delivery, subsequent birth rates were marginally lower after elective Caesarean for breech (adjusted hazard ratio, HR 0.96, 95% CI 0.94-0.98). Larger effects were observed after elective Caesarean for other indications (adjusted HR 0.81, 95% CI 0.78-0.83), and emergency Caesarean (adjusted HR 0.91, 95% CI 0.90-0.93). The effect was smallest for elective Caesarean for breech, and this was not statistically significant in women younger than 30 years of age (adjusted HR 0.98, 95% CI 0.96-1.01). We used birth cohorts from maternity

  20. Estimating mean change in population salt intake using spot urine samples.

    Science.gov (United States)

    Petersen, Kristina S; Wu, Jason H Y; Webster, Jacqui; Grimes, Carley; Woodward, Mark; Nowson, Caryl A; Neal, Bruce

    2016-10-14

    : Spot urine samples are easier to collect than 24-h urine samples and have been used with estimating equations to derive the mean daily salt intake of a population. Whether equations using data from spot urine samples can also be used to estimate change in mean daily population salt intake over time is unknown. We compared estimates of change in mean daily population salt intake based upon 24-h urine collections with estimates derived using equations based on spot urine samples. : Paired and unpaired 24-h urine samples and spot urine samples were collected from individuals in two Australian populations, in 2011 and 2014. Estimates of change in daily mean population salt intake between 2011 and 2014 were obtained directly from the 24-h urine samples and by applying established estimating equations (Kawasaki, Tanaka, Mage, Toft, INTERSALT) to the data from spot urine samples. Differences between 2011 and 2014 were calculated using mixed models. : A total of 1000 participants provided a 24-h urine sample and a spot urine sample in 2011, and 1012 did so in 2014 (paired samples n = 870; unpaired samples n = 1142). The participants were community-dwelling individuals living in the State of Victoria or the town of Lithgow in the State of New South Wales, Australia, with a mean age of 55 years in 2011. The mean (95% confidence interval) difference in population salt intake between 2011 and 2014 determined from the 24-h urine samples was -0.48g/day (-0.74 to -0.21; P  0.058). Separate analysis of the unpaired and paired data showed that detection of change by the estimating equations was observed only in the paired data. : All the estimating equations based upon spot urine samples identified a similar change in daily salt intake to that detected by the 24-h urine samples. Methods based upon spot urine samples may provide an approach to measuring change in mean population salt intake, although further investigation in larger and more diverse population groups is

  1. Correlations in fertility across generations: can low fertility persist?

    Science.gov (United States)

    Kolk, Martin; Cownden, Daniel; Enquist, Magnus

    2014-03-22

    Correlations in family size across generations could have a major influence on human population size in the future. Empirical studies have shown that the associations between the fertility of parents and the fertility of children are substantial and growing over time. Despite their potential long-term consequences, intergenerational fertility correlations have largely been ignored by researchers. We present a model of the fertility transition as a cultural process acting on new lifestyles associated with fertility. Differences in parental and social influences on the acquisition of these lifestyles result in intergenerational correlations in fertility. We show different scenarios for future population size based on models that disregard intergenerational correlations in fertility, models with fertility correlations and a single lifestyle, and models with fertility correlations and multiple lifestyles. We show that intergenerational fertility correlations will result in an increase in fertility over time. However, present low-fertility levels may persist if the rapid introduction of new cultural lifestyles continues into the future.

  2. The influence of male parr body size and mate competition on fertilization success and effective population size in Atlantic salmon.

    Science.gov (United States)

    Jones, M W; Hutchings, J A

    2001-06-01

    Alternative mating strategies in male Atlantic salmon, Salmo salar, are characterized by variability in body size and mate competition. Controlling breeding numbers of larger, older anadromous males, we examined whether body size of mature male parr influenced fertilization success and whether such an association was affected by mate competition among parr. Variation at three to four hypervariable microsatellite loci was used to determine individual paternity of 53-60 offspring from two or three nests from each experimental treatment. Although individual and total parr reproductive success differed significantly among nests within treatments, there was no relationship between parr size and individual reproductive success at any level of competition when anadromous males were involved. However, in a single treatment having no anadromous male, the influence of body size on parr fertilization success was highly significant. Combining data from all treatments, parr body size was an important predictor of the probability of an individual being involved in spawning. We found a negative relationship between total parr reproductive success and intensity of anadromous male competition. To our knowledge, the present study is the first to estimate the effective number of males from individual fertilization success in fish. Our estimates of Ne should not be taken as absolute and may have a downward bias because we did not sample all nests and we used a proxy for lifetime reproductive success. They do, however, illustrate how mature male parr can greatly increase the effective number of males when the latter is estimated from anadromous individuals alone. Although reproductive success by mature male parr increases the effective number of males, this increase seems likely to be most pronounced in natural populations when the number of anadromous males is low.

  3. B(a)P adduct levels and fertility: A cross‑sectional study in a Sicilian population.

    Science.gov (United States)

    Oliveri Conti, Gea; Calogero, Aldo Eugenio; Giacone, Filippo; Fiore, Maria; Barchitta, Martina; Agodi, Antonella; Ferrante, Margherita

    2017-05-01

    Benzo(a)pyrene (BaP) is a carcinogenic polycyclic aromatic hydrocarbon for human tissues. Still today it is not fully investigated if BaP can affect negatively the male fertility through the BaP‑DNA adducts production. In the present study, BaP Tetrol I‑1 (TI‑1) and BaP Tetrol II‑2 (TII‑2) BaP‑DNA adducts were investigated in spermatozoa of a Sicilian male population. Semen samples from 86 volunteers in two eastern Sicilian cities (Regalbuto and Melilli) were collected. The quality of semen was evaluated in all samples according to the World Health Organization (WHO) guidelines. We analyzed BaP‑DNA adducts in extracted sperm cell DNA using the modified high‑performance liquid chromatography‑fluorescence method to detects both Tetrols. Differences between Tetrol levels were assessed by the Wilcoxon signed‑rank test and the Mann‑Whitney U test, as appropriate. Correlation between semen quality parameters and Tetrol concentrations were analyzed using the Spearman's correlation coefficient. Σ(TI‑1+TII‑2) were significantly higher in spermatozoa of volunteers from Regalbuto. Furthermore, a greater dispersion of the levels of adducts was observed in these specimens. TI‑1 adducts were higher than TII‑2 in Melilli samples (95% CI) and TII‑2 were higher than TI‑1 in Regalbuto semen samples (95% CI). A significant inverse correlation between sperm progressive motility and both TI‑1 and TII‑2 adducts was observed. The present study showed that BaP negatively affects male fertility by TI‑1 and TII‑2 DNA‑adduct production. These results suggest that DNA adducts could be used as biomarker to assess BaP exposure by air pollution. Further studies are needed to confirm if these findings could affect male fertility because of the growing impairment of this function observed in recent years.

  4. B(a)P adduct levels and fertility: A cross-sectional study in a Sicilian population

    Science.gov (United States)

    Conti, Gea Oliveri; Calogero, Aldo Eugenio; Giacone, Filippo; Fiore, Maria; Barchitta, Martina; Agodi, Antonella; Ferrante, Margherita

    2017-01-01

    Benzo(a)pyrene (BaP) is a carcinogenic polycyclic aromatic hydrocarbon for human tissues. Still today it is not fully investigated if BaP can affect negatively the male fertility through the BaP-DNA adducts production. In the present study, BaP Tetrol I-1 (TI-1) and BaP Tetrol II-2 (TII-2) BaP-DNA adducts were investigated in spermatozoa of a Sicilian male population. Semen samples from 86 volunteers in two eastern Sicilian cities (Regalbuto and Melilli) were collected. The quality of semen was evaluated in all samples according to the World Health Organization (WHO) guidelines. We analyzed BaP-DNA adducts in extracted sperm cell DNA using the modified high-performance liquid chromatography-fluorescence method to detects both Tetrols. Differences between Tetrol levels were assessed by the Wilcoxon signed-rank test and the Mann-Whitney U test, as appropriate. Correlation between semen quality parameters and Tetrol concentrations were analyzed using the Spearman's correlation coefficient. Σ(TI-1+TII-2) were significantly higher in spermatozoa of volunteers from Regalbuto. Furthermore, a greater dispersion of the levels of adducts was observed in these specimens. TI-1 adducts were higher than TII-2 in Melilli samples (95% CI) and TII-2 were higher than TI-1 in Regalbuto semen samples (95% CI). A significant inverse correlation between sperm progressive motility and both TI-1 and TII-2 adducts was observed. The present study showed that BaP negatively affects male fertility by TI-1 and TII-2 DNA-adduct production. These results suggest that DNA adducts could be used as biomarker to assess BaP exposure by air pollution. Further studies are needed to confirm if these findings could affect male fertility because of the growing impairment of this function observed in recent years. PMID:28350051

  5. The CFTR Met 470 allele is associated with lower birth rates in fertile men from a population isolate.

    Directory of Open Access Journals (Sweden)

    Gülüm Kosova

    2010-06-01

    Full Text Available Although little is known about the role of the cystic fibrosis transmembrane regulator (CFTR gene in reproductive physiology, numerous variants in this gene have been implicated in etiology of male infertility due to congenital bilateral absence of the vas deferens (CBAVD. Here, we studied the fertility effects of three CBAVD-associated CFTR polymorphisms, the (TGm and polyT repeat polymorphisms in intron 8 and Met470Val in exon 10, in healthy men of European descent. Homozygosity for the Met470 allele was associated with lower birth rates, defined as the number of births per year of marriage (P = 0.0029. The Met470Val locus explained 4.36% of the phenotypic variance in birth rate, and men homozygous for the Met470 allele had 0.56 fewer children on average compared to Val470 carrier men. The derived Val470 allele occurs at high frequencies in non-African populations (allele frequency = 0.51 in HapMap CEU, whereas it is very rare in African population (Fst = 0.43 between HapMap CEU and YRI. In addition, haplotypes bearing Val470 show a lack of genetic diversity and are thus longer than haplotypes bearing Met470 (measured by an integrated haplotype score [iHS] of -1.93 in HapMap CEU. The fraction of SNPs in the HapMap Phase2 data set with more extreme Fst and iHS measures is 0.003, consistent with a selective sweep outside of Africa. The fertility advantage conferred by Val470 relative to Met470 may provide a selective mechanism for these population genetic observations.

  6. MODIFIED REGRESSION APPROACH IN PREDICTION OF FINITE POPULATION MEAN USING KNOWN COEFFICIENT OF VARIATION

    Directory of Open Access Journals (Sweden)

    Sheela Misra

    2013-01-01

    Full Text Available In this paper,we are utilizingthe modified regression approach for the prediction offinite population mean, with known coefficient of variation of study variabley, undersimplerandom sampling without replacement. The bias and mean square error of the proposed estimatorare obtained and compared with the usual regression estimator of the population mean and comesout to be more efficient in the sense of having lesser meansquare error. The optimum class ofestimators is obtained and for the greater practical utility proposed optimum estimator based onestimated optimum value of the characterizing scalar is also obtained and is shown to retain thesame efficiency to the first order of approximation as the former one. A numerical illustration isalso given to support the theoretical conclusions.

  7. Maternal use of fertility drugs and risk of cancer in children--a nationwide population-based cohort study in Denmark

    DEFF Research Database (Denmark)

    Hargreave, Marie; Jensen, Allan; Nielsen, Thor Schütt Svane

    2015-01-01

    and follicle-stimulating hormone], gonadotropin-releasing hormone analogs, human chorionic gonadotropins, progesterone and other fertility drugs). We found no statistically significant association between maternal use of fertility drugs and risk for overall cancer in childhood or young adulthood. However......Large population-based studies are needed to examine the effect of maternal use of fertility drugs on the risk of cancer in children, while taking into account the effect of the underlying infertility. A cohort of 123,322 children born in Denmark between 1964 and 2006 to 68,255 women who had been...... evaluated for infertility was established. We used a case-cohort design and calculated hazard ratios (HRs) for cancer in childhood (0-19 years) and in young adulthood (20-29 years) associated with maternal use of six groups of fertility drugs (clomiphene, gonadotropins [i.e., human menopausal gonadotropins...

  8. A population-based survey on family intentions and fertility awareness in women and men in the United Kingdom and Denmark

    DEFF Research Database (Denmark)

    Vassard, Ditte; Lallemant, Camille; Nyboe Andersen, Anders

    2016-01-01

    BACKGROUND: Across several European countries family formation is increasingly postponed. The aims of the study were to investigate the desire for family building and fertility awareness in the UK and Denmark. METHODS: A population-based internet survey was used among women (n = 1,000) and men (n...... = 237) from the UK (40%) and Denmark (60%). Data covered socio-demographics, family formation, and awareness of female age-related fertility. Data analysis used descriptive statistics and logistic regression analysis for studying associations between low fertility awareness and desired family formation....... RESULTS: The majority of all participants desired two or three children. Two-thirds of the childless participants desired a first child at 30+ years, and one-fifth of the women and one-third of the men desired a last child at age 40. Overall, 83% of women and 73% of men were aware that female fertility...

  9. A population-based survey on family intentions and fertility awareness in women and men in the United Kingdom and Denmark

    DEFF Research Database (Denmark)

    Vassard, Ditte; Lallemant, Camille; Nyboe Andersen, Anders;

    2016-01-01

    BACKGROUND: Across several European countries family formation is increasingly postponed. The aims of the study were to investigate the desire for family building and fertility awareness in the UK and Denmark. METHODS: A population-based internet survey was used among women (n = 1,000) and men (n....... RESULTS: The majority of all participants desired two or three children. Two-thirds of the childless participants desired a first child at 30+ years, and one-fifth of the women and one-third of the men desired a last child at age 40. Overall, 83% of women and 73% of men were aware that female fertility......-related decrease in female fertility, most desired having children at an age when female fertility has declined. Women who were not sufficiently aware of the impact of advanced age were significantly more likely to have their first child at a higher age. There is a need for developing educational programs...

  10. Adolescent fertility: worldwide concerns.

    Science.gov (United States)

    Senderowitz, J; Paxman, J M

    1985-04-01

    There is growing concern over the adverse health, social, economic, and demographic effects of adolescent fertility. Morbidity and mortality rates ar significantly higher for teenage mothers and their infants, and early initiation of childbearing generally means truncated education, lower future family income, and larger completed family size. Adolescent fertility rates, which largely reflect marriage patterns, range from 4/1000 in Mauritania; in sub-Saharan Africa, virtually all rates are over 100. In most countries, adolescent fertility rates are declining due to rising age at marriage, increased educational and economic opportunities for young women, changes in social customs, increased use of contraception, and access to abortion. However, even if fertility rates were to decline dramatically among adolescent women in developing countries, their sheer numbers imply that their fertility will have a major impact on world population growth in the years ahead. The number of women in the world ages 15-19 years is expected to increase from 245 million in 1985 to over 320 million in the years 2020; 82% of these women live in developing countries. As a result of more and earlier premarital sexual activity, fostered by the lengthening gap between puberty and marriage, diminished parental and social controls, and increasing peer and media pressure to be sexually active, abortion and out-of-wedlock childbearing are increasing among teenagers in many developed and rapidly urbanizing developing countries. Laws and policies regarding sex education in the schools and access to family planning services by adolescents can either inhibit or support efforts to reduce adolescent fertility. Since contraceptive use is often sporadic and ineffective among adolescents, family planning services are crucial. Such programs should aim to reduce adolescents' dependence on abortion through preventive measures and increase awareness of the benefits of delayed sexual activity. Similarly, sex

  11. A False Fertility Transition: The Case of American Blacks. Papers of the East-West Population Institute, No. 90.

    Science.gov (United States)

    Wright, Paul; Pirie, Peter

    The decline in black fertility after the Civil War to its lowest level about the year 1936 does not fit the typical demographic transition pattern in which fertility declines postdate the initiation of mortality declines. Instead, for blacks much of the fertility decline (56 percent) was due to "involuntary infertility" related to venereal…

  12. A FAMILY OF ESTIMATORS FOR ESTIMATING POPULATION MEAN IN STRATIFIED SAMPLING UNDER NON-RESPONSE

    Directory of Open Access Journals (Sweden)

    Manoj K. Chaudhary

    2009-01-01

    Full Text Available Khoshnevisan et al. (2007 proposed a general family of estimators for population mean using known value of some population parameters in simple random sampling. The objective of this paper is to propose a family of combined-type estimators in stratified random sampling adapting the family of estimators proposed by Khoshnevisan et al. (2007 under non-response. The properties of proposed family have been discussed. We have also obtained the expressions for optimum sample sizes of the strata in respect to cost of the survey. Results are also supported by numerical analysis.

  13. The evolution of transposable elements in natural populations of self-fertilizing Arabidopsis thaliana and its outcrossing relative Arabidopsis lyrata

    Directory of Open Access Journals (Sweden)

    Gaut Brandon S

    2010-01-01

    Full Text Available Abstract Background Transposable Elements (TEs make up the majority of plant genomes, and thus understanding TE evolutionary dynamics is key to understanding plant genome evolution. Plant reproductive systems are diverse and mating type variation is one factor among many hypothesized to influence TE evolutionary dynamics. Here, we collected a large TE-display data set in self-fertilizing Arabidopsis thaliana, and compared it to data gathered in outcrossing Arabidopsis lyrata. We analyzed seven TE families in four natural populations of each species to tease apart the effects of mating system, demography, transposition, and selection in determining patterns of TE diversity. Results Measures of TE band differentiation were largely consistent across TE families. However, patterns of diversity in A. thaliana Ac elements differed significantly from that other TEs, perhaps signaling a lack of recent transposition. Across TE families, we estimated higher allele frequencies and lower selection coefficients on A. thaliana TE insertions relative to A. lyrata TE insertions. Conclusions The differences in TE distributions between the two Arabidopsis species represents a synthesis of evolutionary forces that include the transposition dynamics of individual TE families and the demographic histories of populations. There are also species-specific differences that could be attributed to the effects of mating system, including higher overall allele frequencies in the selfing lineage and a greater proportion of among population TE diversity in the outcrossing lineage.

  14. Finding the Balance: Fertility Control for the Management of Fragmented Populations of a Threatened Rock-Wallaby Species

    Directory of Open Access Journals (Sweden)

    Nicole Willers

    2015-12-01

    Full Text Available Populations of Australian marsupials can become overabundant, resulting in detrimental impacts on the environment. For example, the threatened black-flanked rock-wallaby ( Petrogale lateralis lateralis has previously been perceived as overabundant and thus ‘unwanted’ when they graze crops and cause habitat degradation. Hormonally-induced fertility control has been increasingly used to manage population size in other marsupials where alternative management options are not viable. We tested whether deslorelin, a superagonist of gonadotropin-releasing hormone (GnRH, would suppress reproduction in free-living adult female rock-wallabies without adversely impacting body condition. We trapped, synchronised reproduction and allocated female rock-wallabies to a placebo implant (control, n = 22, one (n = 22 or two (n = 20 subcutaneous implants of deslorelin. Females were then recaptured over the following 36 months to monitor reproduction, including Luteinising Hormone levels, and body condition. Following treatment, diapaused blastocysts reactivated in five females and the resulting young were carried through to weaning. No wallabies treated with deslorelin, conceivede a new young for at least 27 months. We did not observe adverse effects on body condition on treated females. We conclude that deslorelin implants are effective for the medium-term suppression of reproduction in female black-flanked rock-wallabies and for managing overabundant populations of some marsupials.

  15. The decrease in the population of Gluconacetobacter diazotrophicus in sugarcane after nitrogen fertilization is related to plant physiology in split root experiments.

    Science.gov (United States)

    Rodríguez-Andrade, Osvaldo; Fuentes-Ramírez, Luis E; Morales-García, Yolanda E; Molina-Romero, Dalia; Bustillos-Cristales, María R; Martínez-Contreras, Rebeca D; Muñoz-Rojas, Jesús

    2015-01-01

    It has been established that a decrease in the population of Gluconacetobacter diazotrophicus associated with sugarcane occurs after nitrogen fertilization. This fact could be due to a direct influence of NH(4)NO(3) on bacterial cells or to changes in plant physiology after fertilizer addition, affecting bacterial establishment. In this work, we observed that survival of G. diazotrophicus was directly influenced when 44.8mM of NH(4)NO(3) (640mgN/plant) was used for in vitro experiments. Furthermore, micropropagated sugarcane plantlets were inoculated with G. diazotrophicus and used for split root experiments, in which both ends of the system were fertilized with a basal level of NH(4)NO(3) (0.35mM; 10mgN/plant). Twenty days post inoculation (dpi) one half of the plants were fertilized with a high dose of NH(4)NO(3) (6.3mM; 180 mgN/plant) on one end of the system. This nitrogen level was lower than that directly affecting G. diazotrophicus cells; however, it caused a decrease in the bacterial population in comparison with control plants fertilized with basal nitrogen levels. The decrease in the population of G. diazotrophicus was higher in pots fertilized with a basal nitrogen level when compared with the corresponding end supplied with high levels of NH4NO3 (100dpi; 80 days post fertilization) of the same plant system. These observations suggest that the high nitrogen level added to the plants induce systemic physiological changes that affect the establishment of G. diazotrophicus.

  16. Influence of plant population and nitrogen-fertilizer at various levels on growth and growth efficiency of maize.

    Science.gov (United States)

    Tajul, M I; Alam, M M; Hossain, S M M; Naher, K; Rafii, M Y; Latif, M A

    2013-01-01

    Field experiments were conducted to evaluate plant population and N-fertilizer effects on yield and yield components of maize (Zea mays L.). Three levels of plant populations (53000, 66000, and 800,000 plants ha⁻¹ corresponding to spacings of 75 × 25, 60 × 25, and 50 × 25 cm) and 4 doses of N (100, 140, 180, and 220 kg ha⁻¹) were the treatment variables. Results revealed that plant growth, light interception (LI), yield attributes, and grain yield varied significantly due to the variations in population density and N-rates. Crop growth rate (CGR) was the highest with the population of 80,000 ha⁻¹ receiving 220 kg N ha⁻¹, while relative growth rate (RGR) showed an opposite trend of CGR. Light absorption was maximum when most of densely populated plant received the highest amount of N (220 kg N ha⁻¹). Response of soil-plant-analysis development (SPAD) value as well as N-content to N-rates was found significant. Plant height was the maximum at the lowest plant density with the highest amount of N. Plants that received 180 kg N ha⁻¹ with 80,000 plants ha⁻¹ had larger foliage, greater SPAD value, and higher amount of grains cob⁻¹ that contributed to the maximum yield (5.03 t ha⁻¹) and the maximum harvest index (HI) compared to the plants in other treatments.

  17. Influence of Plant Population and Nitrogen-Fertilizer at Various Levels on Growth and Growth Efficiency of Maize

    Directory of Open Access Journals (Sweden)

    M. I. Tajul

    2013-01-01

    Full Text Available Field experiments were conducted to evaluate plant population and N-fertilizer effects on yield and yield components of maize (Zea mays L.. Three levels of plant populations (53000, 66000, and 800000 plants ha−1 corresponding to spacings of 75 × 25, 60 × 25, and 50 × 25 cm and 4 doses of N (100, 140, 180, and 220 kg ha−1 were the treatment variables. Results revealed that plant growth, light interception (LI, yield attributes, and grain yield varied significantly due to the variations in population density and N-rates. Crop growth rate (CGR was the highest with the population of 80,000 ha−1 receiving 220 kg N ha−1, while relative growth rate (RGR showed an opposite trend of CGR. Light absorption was maximum when most of densely populated plant received the highest amount of N (220 kg N ha−1. Response of soil-plant-analysis development (SPAD value as well as N-content to N-rates was found significant. Plant height was the maximum at the lowest plant density with the highest amount of N. Plants that received 180 kg N ha−1 with 80,000 plants ha−1 had larger foliage, greater SPAD value, and higher amount of grains cob−1 that contributed to the maximum yield (5.03 t ha−1 and the maximum harvest index (HI compared to the plants in other treatments.

  18. Is Wildlife Fertility Control Always Humane?

    Directory of Open Access Journals (Sweden)

    Jordan O. Hampton

    2015-10-01

    Full Text Available Investigation of fertility control techniques to reduce reproductive rates in wildlife populations has been the source of much research. Techniques targeting wildlife fertility have been diverse. Most research into fertility control methods has focused upon efficacy, with few studies rigorously assessing animal welfare beyond opportunistic anecdote. However, fertility control techniques represent several very different mechanisms of action (modalities, each with their own different animal welfare risks. We provide a review of the mechanisms of action for fertility control methods, and consider the role of manipulation of reproductive hormones (“endocrine suppression” for the long-term ability of animals to behave normally. We consider the potential welfare costs of animal manipulation techniques that are required to administer fertility treatments, including capture, restraint, surgery and drug delivery, and the requirement for repeated administration within the lifetime of an animal. We challenge the assumption that fertility control modalities generate similar and desirable animal welfare outcomes, and we argue that knowledge of reproductive physiology and behaviour should be more adeptly applied to wild animal management decisions. We encourage wildlife managers to carefully assess long-term behavioural risks, associated animal handling techniques, and the importance of positive welfare states when selecting fertility control methods as a means of population control.

  19. Population processes and Philippine social institutions: a review of existing literature on the impact of fertility and migration on the family, the political institution and the church.

    Science.gov (United States)

    Guerrero, S H; Ballescas, M R

    1987-01-01

    This article provides a review of the literature on the much neglected area of the consequences of population processes. Specifically described are those studies relating to the sociocultural and economic impact or population processes (migration and fertility) on the family, the political institution, and the church in the Philippines. Discussion of the family consequences focuses on the effects on health and nutrition, decision making, roles and status of women, husband and wife communication, values and norms, values of children, policies and programs. Institutional effects are discussed in terms of the urban poor, ethnic tribal groups and grass roots organizations. There is a substantial limitation and gap in the literature on the interrelationships among institutions and the dimensions of specific institutions. It is also pointed out there are methodological problems in specification, data collection, and analysis which have implications for policy intervention. There is a need in institutional analyses to include multilevels (individual, household, and aggregate). Assessing the impact of fertility and migration requires micro and macro level analysis. Methodology and data which are used in systematic studies of determinants are not as easily used in impact studies. There is inadequate identification of target populations, and a lack of comprehensive qualitative and quantitative description of the impact on these subgroups. Hence the failure and inadequacy of existing policies arises when there is emphasis on a homogenous population. An example of the paper's organization is as follows: the impact of fertility on the family as a whole (health and nutrition effect on parents) health effects on mother, labor force participation, and there relationship between husband and wife); and the effects on children (health effects, intellectual and mental growth, personality and social adjustment, income/poverty). The fertility impact on the political institutions is

  20. Rhythmic behavior in a two-population mean field Ising model

    CERN Document Server

    Collet, Francesca; Tovazzi, Daniele

    2016-01-01

    Many real systems comprised of a large number of interacting components, as for instance neural networks , may exhibit collective periodic behavior even though single components have no natural tendency to behave periodically. Macroscopic oscillations are indeed one of the most common self-organized behavior observed in living systems. In the present paper we study some dynamical features of a two-population generalization of the mean field Ising model with the scope of investigating simple mechanisms capable to generate rhythm in large groups of interacting individuals. We show that the system may undergo a transition from a disordered phase, where the magnetization of each population fluctuates closely around zero, to a phase in which they both display a macroscopic regular rhythm. In particular, there exists a region in the parameter space where having two groups of spins with inter- and intra-population interactions of different strengths suffices for the emergence of a robust periodic behavior.

  1. Public pensions and population ageing : An economic analysis of fertility, migration and social-security policy

    NARCIS (Netherlands)

    Leers, T.

    2001-01-01

    This thesis examines the relation between the changing demographic composition of the population and its economic, political and international consequences from an economic-theoretical point of view. The ample current interest in this subject needs little comment. In the OECD-countries, virtually no

  2. Public pensions and population ageing : An economic analysis of fertility, migration and social-security policy

    NARCIS (Netherlands)

    Leers, T.

    2001-01-01

    This thesis examines the relation between the changing demographic composition of the population and its economic, political and international consequences from an economic-theoretical point of view. The ample current interest in this subject needs little comment. In the OECD-countries, virtually no

  3. Analysis of Fusarium populations in a soybean field under different fertilization management by real-time quantitative PCR and denaturing gradient gel electrophoresis

    Science.gov (United States)

    The abundance and population structure of Fusarium spp. in field soils were assessed to determine the effect of different fertilization treatments on soil microbial community and potential role in disease management. The field was under soybean-wheat-corn rotation located in the black soil (Udic Mo...

  4. The influence of mineral fertilizer combined with a nitrification inhibitor on microbial populations and activities in calcareous Uzbekistanian soil under cotton cultivation.

    Science.gov (United States)

    Egamberdiyeva, D; Mamiev, M; Poberejskaya, S K

    2001-10-30

    Application of fertilizers combined with nitrification inhibitors affects soil microbial biomass and activity. The objective of this research was to determine the effects of fertilizer application combined with the nitrification inhibitor potassium oxalate (PO) on soil microbial population and activities in nitrogen-poor soil under cotton cultivation in Uzbekistan. Fertilizer treatments were N as urea, P as ammophos, and K as potassium chloride. The nitrification inhibitor PO was added to urea and ammophos at the rate of 2%. Three treatments--N200 P140 K60 (T1), N200 PO P140 K60 (T2), and N200 P140 PO K60 (T3) mg kg(-1) soil--were applied for this study. The control (C) was without fertilizer and PO. The populations of oligotrophic bacteria, ammonifying bacteria, nitrifying bacteria, denitrifying bacteria, mineral assimilating bacteria, oligonitrophilic bacteria, and bacteria group Azotobacter were determined by the most probable number method. The treatments T2 and T3 increased the number of oligonitrophilic bacteria and utilization mineral forms of nitrogen on the background of reducing number of ammonifying bacteria. T2 and T3 also decreased the number of nitrifying bacteria, denitrifying bacteria, and net nitrification. In conclusion, our experiments showed that PO combined with mineral fertilizer is one of the most promising compounds for inhibiting nitrification rate, which was reflected in the increased availability and efficiency of fertilizer nitrogen to the cotton plants. PO combined with mineral fertilizer has no negative effects on nitrogen-fixing bacteria Azotobacter and oligo-nitrophilic bacteria.

  5. The Influence of Mineral Fertilizer Combined With a Nitrification Inhibitor on Microbial Populations and Activities in Calcareous Uzbekistanian Soil Under Cotton Cultivation

    Directory of Open Access Journals (Sweden)

    Dilfuza Egamberdiyeva

    2001-01-01

    Full Text Available Application of fertilizers combined with nitrification inhibitors affects soil microbial biomass and activity. The objective of this research was to determine the effects of fertilizer application combined with the nitrification inhibitor potassium oxalate (PO on soil microbial population and activities in nitrogen-poor soil under cotton cultivation in Uzbekistan. Fertilizer treatments were N as urea, P as ammophos, and K as potassium chloride. The nitrification inhibitor PO was added to urea and ammophos at the rate of 2%. Three treatments—N200P140K60 (T1, N200 P140 POK60 (T2, and N200 P140 POK60 (T3 mg kg-1 soil—were applied for this study. The control (C was without fertilizer and PO. The populations of oligotrophic bacteria, ammonifying bacteria, nitrifying bacteria, denitrifying bacteria, mineral assimilating bacteria, oligonitrophilic bacteria, and bacteria group Azotobacter were determined by the most probable number method. The treatments T2 and T3 increased the number of oligonitrophilic bacteria and utilization mineral forms of nitrogen on the background of reducing number of ammonifying bacteria. T2 and T3 also decreased the number of nitrifying bacteria, denitrifying bacteria, and net nitrification. In conclusion, our experiments showed that PO combined with mineral fertilizer is one of the most promising compounds for inhibiting nitrification rate, which was reflected in the increased availability and efficiency of fertilizer nitrogen to the cotton plants. PO combined with mineral fertilizer has no negative effects on nitrogen-fixing bacteria Azotobacter and oligo-nitrophilic bacteria.

  6. Mean-field dynamics of a population of stochastic map neurons

    Science.gov (United States)

    Franović, Igor; Maslennikov, Oleg V.; Bačić, Iva; Nekorkin, Vladimir I.

    2017-07-01

    We analyze the emergent regimes and the stimulus-response relationship of a population of noisy map neurons by means of a mean-field model, derived within the framework of cumulant approach complemented by the Gaussian closure hypothesis. It is demonstrated that the mean-field model can qualitatively account for stability and bifurcations of the exact system, capturing all the generic forms of collective behavior, including macroscopic excitability, subthreshold oscillations, periodic or chaotic spiking, and chaotic bursting dynamics. Apart from qualitative analogies, we find a substantial quantitative agreement between the exact and the approximate system, as reflected in matching of the parameter domains admitting the different dynamical regimes, as well as the characteristic properties of the associated time series. The effective model is further shown to reproduce with sufficient accuracy the phase response curves of the exact system and the assembly's response to external stimulation of finite amplitude and duration.

  7. How does variance in fertility change over the demographic transition?

    Science.gov (United States)

    Hruschka, Daniel J; Burger, Oskar

    2016-04-19

    Most work on the human fertility transition has focused on declines in mean fertility. However, understanding changes in the variance of reproductive outcomes can be equally important for evolutionary questions about the heritability of fertility, individual determinants of fertility and changing patterns of reproductive skew. Here, we document how variance in completed fertility among women (45-49 years) differs across 200 surveys in 72 low- to middle-income countries where fertility transitions are currently in progress at various stages. Nearly all (91%) of samples exhibit variance consistent with a Poisson process of fertility, which places systematic, and often severe, theoretical upper bounds on the proportion of variance that can be attributed to individual differences. In contrast to the pattern of total variance, these upper bounds increase from high- to mid-fertility samples, then decline again as samples move from mid to low fertility. Notably, the lowest fertility samples often deviate from a Poisson process. This suggests that as populations move to low fertility their reproduction shifts from a rate-based process to a focus on an ideal number of children. We discuss the implications of these findings for predicting completed fertility from individual-level variables. © 2016 The Author(s).

  8. Mapping QTLs for Fertility Restoration of Different Cytoplasmic Male Sterility Types in Rice Using Two Oryza sativa ×O. rufipogon Backcross Inbred Line Populations

    OpenAIRE

    Biao-lin Hu; Jian-kun Xie; Yong Wan; Jin-wei Zhang; Fan-tao Zhang; Xia Li

    2016-01-01

    Hybrid rice breeding using cytoplasmic male sterility/fertility restoration (CMS/Rf) systems plays an important role in ensuring global food security. Two backcross inbred line (BIL) populations derived from either Xieqingzao B (XB)//XB/Dongxiang wild rice (DWR) (XXD) or XB//DWR/XB (XDX) were used to detect quantitative trait loci (QTLs) for fertility restoration of Dwarf wild abortive- (DA-), Indonesia Paddy- (ID-), and DWR-type CMS in rice. Lines with ID- and DA-type CMS were testcrossed wi...

  9. Adapting Meaning-Centered Psychotherapy in Advanced Cancer for the Chinese Immigrant Population.

    Science.gov (United States)

    Leng, Jennifer; Lui, Florence; Chen, Angela; Huang, Xiaoxiao; Breitbart, William; Gany, Francesca

    2017-04-28

    The Chinese immigrant community faces multiple barriers to quality cancer care and cancer survivorship. Meaning-centered psychotherapy (MCP) is an empirically-based treatment shown to significantly reduce psychological distress while increasing spiritual well-being and a sense of meaning and purpose in life in advanced cancer patients. However, it has not yet been adapted for racial and ethnic minority populations for whom the concept of "meaning" may likely differ from that of westernized White populations. In this study, we conducted a community needs assessment to inform the cultural adaptation of MCP for Chinese patients with advanced cancer, in accordance with Bernal et al. ecological validity model and the cultural adaptation process model of Domenech-Rodriquez and Weiling. We conducted interviews until saturation with 11 key Chinese-serving community leaders and health professionals with a range of areas of expertise (i.e. oncology, psychology, palliative care, cancer support services), to examine community needs, priorities, and preferences within the context of the MCP intervention. Sessions were audio recorded and transcribed. The research team analyzed the transcripts using Atlas.ti. Six frequently occurring themes were identified. Interviewees described the role of the family, traditional Chinese values, cancer stigma, and social norms (e.g. saving face) in adapting MCP. Researchers and clinicians should consider the role of the family in treatment, as well as specific social and cultural values and beliefs in adapting and delivering MCP for Chinese patients with advanced cancer.

  10. Linking population, fertility, and family planning with adaptation to climate change: perspectives from Ethiopia.

    Science.gov (United States)

    Rovin, Kimberly; Hardee, Karen; Kidanu, Aklilu

    2013-09-01

    Global climate change is felt disproportionately in the world's most economically disadvantaged countries. As adaption to an evolving climate becomes increasingly salient on national and global scales, it is important to assess how people at the local-level are already coping with changes. Understanding local responses to climate change is essential for helping countries to construct strategies to bolster resilience to current and future effects. This qualitative research investigated responses to climate change in Ethiopia; specifically, how communities react to and cope with climate variation, which groups are most vulnerable, and the role of family planning in increasing resilience. Participants were highly aware of changing climate effects, impacts of rapid population growth, and the need for increased access to voluntary family planning. Identification of family planning as an important adaptation strategy supports the inclusion of rights-based voluntary family planning and reproductive health into local and national climate change adaptation plans.

  11. Rhythmic behavior in a two-population mean-field Ising model

    Science.gov (United States)

    Collet, Francesca; Formentin, Marco; Tovazzi, Daniele

    2016-10-01

    Many real systems composed of a large number of interacting components, as, for instance, neural networks, may exhibit collective periodic behavior even though single components have no natural tendency to behave periodically. Macroscopic oscillations are indeed one of the most common self-organized behavior observed in living systems. In the present paper we study some dynamical features of a two-population generalization of the mean-field Ising model with the scope of investigating simple mechanisms capable to generate rhythms in large groups of interacting individuals. We show that the system may undergo a transition from a disordered phase, where the magnetization of each population fluctuates closely around zero, to a phase in which they both display a macroscopic regular rhythm. In particular, there exists a region in the parameter space where having two groups of spins with inter- and intrapopulation interactions of different strengths suffices for the emergence of a robust periodic behavior.

  12. Confidence Intervals for the Coefficient of Variation in a Normal Distribution with a Known Population Mean

    Directory of Open Access Journals (Sweden)

    Wararit Panichkitkosolkul

    2013-01-01

    Full Text Available This paper presents three confidence intervals for the coefficient of variation in a normal distribution with a known population mean. One of the proposed confidence intervals is based on the normal approximation. The other proposed confidence intervals are the shortest-length confidence interval and the equal-tailed confidence interval. A Monte Carlo simulation study was conducted to compare the performance of the proposed confidence intervals with the existing confidence intervals. Simulation results have shown that all three proposed confidence intervals perform well in terms of coverage probability and expected length.

  13. Improved Estimation of Population Mean Using Median and Coefficient of Variation of Auxiliary Variable

    Directory of Open Access Journals (Sweden)

    Subhash Kumar Yadav,

    2014-01-01

    Full Text Available This manuscript deals with the estimation of population mean of the variable under study using an improved ratio type estimator utilizing the known values of median and coefficient of variation of auxiliary variable. The expressions for the bias and mean square error (MSE of the proposed estimator are obtained up to the first order of approximation. The optimum estimator is also obtained for the optimum value of the constant of the estimator and its optimum properties are also studied. It is shown that the proposed estimator is better than the existing ratio estimators in the literature. For the justification of the improvement of the proposed estimator over others, an empirical study is also carried out.

  14. Efficacy of Vermicompost against fertilizers on Cicer and Pisum and on population diversity of N2 fixing bacteria.

    Science.gov (United States)

    Sinha, Jayanta; Biswas, Chanchal Kumar; Ghosh, Arup; Saha, Amit

    2010-05-01

    Vermicompost is a very important biofertilizer produced through the artificial cultivation of worms i.e. Vermiculture. Vermicompost is enriched with all beneficial soil bacteria and also contain many of the essential plant nutrients like N, P, K and micronutrients. It increases soil aeration, texture and jilt. In this work, study is being carried out to find out the effect of different fertilizers such as DAF, FYM and Vermicompost on various morphological parameters and on the in vitro growth of bacterial colonies and its diversity in relation to two important leguminous plants such as Pisum sp. and Cicer sp. Results showed that plant grown in Vermicompost pretreated soil exhibited maximum increase in all morphological parameters such as root length, shoot length, number of root branches, number of stem branches, number of leaves, number of flowers, number of pods and number of root nodules in four months sampling in comparison to untreated, FYM treated and DAP treated soils. Further in Vermicompost pretreated soil, number of N2 fixing bacterial colony was maximum and showed highest diversity indices (1.6 and 0.99 and 2.0 and 0.99 for Cicer sp. and Pisum sp. respectively) than FYM, DAP and untreated control. Thus not only does the Vermicompost stimulate plant growth but also it increases the N2 fixing bacterial population in soil and also its diversity.

  15. Mating Type Alleles,Female Fertility and Genetic Diversity of Magnaporthe grisea Populations Pathogenic to Rice from Some Asian Countries

    Institute of Scientific and Technical Information of China (English)

    SHEN Ying; Joelle Milazzo; YUAN Xiao-ping; Henry Adreit; WANG Yan-li; Jean Loup Notteghem; Didier Tharreau

    2003-01-01

    Five hundred and twenty-two isolates of Magnaporthe grisea isolated from rice in 5 Asian countries were characterized for their mating type by crossing them with 4 hermaphroditic isolates (KA3 and TH2: MAT1.1; Guy11 and TH-16: MAT1.2). Among them, 41% were MAT1.1 and 25% were MAT1.2.The remaining 34% did not produce perithecia with any of the 4 hermaphroditic testers. In Bangladesh, India,Nepal, Vietnam and in most provinces of China, both mating types were present. Only one mating type was found in 3 provinces and 1 city of China. Almost all the isolates had very low fertility, as they were in general female sterile and sometimes also male sterile. Hermaphroditic isolates were recovered from the 5 countries. In these countries, they represented between 13% and 75% of the isolates. In Zhejiang, Guizhou, Guangdong,Hunan, Yunnan and H-ubei provinces of China, hermaphroditic isolates represented between 6% and 67%.The genetic diversity of 143 isolates from these countries and provinces, where hermaphroditic isolates had been collected, was analyzed using SCAR markers. Genetic diversity was high and population structure did not resemble classical clonal structure described in most rice growing regions. The existence of sexual reproduction in the field, localization of a center of diversity in China, and migration between countries were discussed in this paper.

  16. Inheritance of fertility in broiler chickens

    Directory of Open Access Journals (Sweden)

    Olori Victor E

    2009-10-01

    Full Text Available Abstract Background The fertility of a chicken's egg is a trait which depends on both the hen that lays the egg and on her mate. It is also known that fertility of an individual changes over the laying period. Methods Longitudinal models including both random genetic and permanent environmental effects of both the female and her male mate were used to model the proportion of fertile eggs in a pedigree broiler population over the ages 29-54 weeks. Results Both the male and the female contribute to variation in fertility. Estimates of heritability of weekly records were typically 7% for female and 10% for male contributions to fertility. Repeatability estimates ranged from 24 to 33%, respectively. The estimated genetic variance remained almost constant for both sexes over the laying period and the genetic correlations between different ages were close to 1.0. The permanent environment components increased substantially towards the end of the analyzed period, and correlations between permanent environment effects at different ages declined with increasing age difference The heritability of mean fertility over the whole laying period was estimated at 13% for females and 17% for males. A small positive correlation between genetic effects for male and female fertility was found. Conclusion Opportunities to improve fertility in broiler stocks by selection on both sexes exist and should have an impact throughout the laying period.

  17. Fertility preservation in young patients with cancer

    Directory of Open Access Journals (Sweden)

    Virender Suhag

    2015-01-01

    Full Text Available Infertility can arise as a consequence of treatment of oncological conditions. The parallel and continued improvement in both the management of oncology and fertility cases in recent times has brought to the forefront the potential for fertility preservation in patients being treated for cancer. Many survivors will maintain their reproductive potential after the successful completion of treatment for cancer. However total body irradiation, radiation to the gonads, and certain high dose chemotherapy regimens can place women at risk for acute ovarian failure or premature menopause and men at risk for temporary or permanent azoospermia. Providing information about risk of infertility and possible interventions to maintain reproductive potential are critical for the adolescent and young adult population at the time of diagnosis. There are established means of preserving fertility before cancer treatment; specifically, sperm cryopreservation for men and in vitro fertilization and embryo cryopreservation for women. Several innovative techniques are being actively investigated, including oocyte and ovarian follicle cryopreservation, ovarian tissue transplantation, and in vitro follicle maturation, which may expand the number of fertility preservation choices for young cancer patients. Fertility preservation may also require some modification of cancer therapy; thus, patients' wishes regarding future fertility and available fertility preservation alternatives should be discussed before initiation of therapy.

  18. Biometric variability of goat populations revealed by means of principal component analysis.

    Science.gov (United States)

    Pires, Luanna Chácara; Machado, Théa M Medeiros; Araújo, Adriana Mello; Olson, Timothy A; da Silva, João Batista Lopes; Torres, Robledo Almeida; Costa, Márcio da Silva

    2012-12-01

    The aim was to analyze variation in 12 Brazilian and Moroccan goat populations, and, through principal component analysis (PCA), check the importance of body measures and their indices as a means of distinguishing among individuals and populations. The biometric measurements were wither height (WH), brisket height (BH) and ear length (EL). Thorax depth (WH-BH) and the three indices, TD/WH, EL/TD and EL/WH, were also calculated. Of the seven components extracted, the first three principal components were sufficient to explain 99.5% of the total variance of the data. Graphical dispersion by genetic groups revealed that European dairy breeds clustered together. The Moroccan breeds were separated into two groups, one comprising the Drâa and the other the Zagora and Rhâali breeds. Whereas, on the one side, the Anglo-Nubian and undefined breeds were the closest to one another the goats of the Azul were observed to have the highest variation of all the breeds. The Anglo-Nubian and Boer breeds were similar to each other. The Nambi-type goats remained distinct from all the other populations. In general, the use of graphical representation of PCA values allowed to distinguish genetic groups.

  19. Biometric variability of goat populations revealed by means of principal component analysis

    Directory of Open Access Journals (Sweden)

    Luanna Chácara Pires

    2012-01-01

    Full Text Available The aim was to analyze variation in 12 Brazilian and Moroccan goat populations, and, through principal component analysis (PCA, check the importance of body measures and their indices as a means of distinguishing among individuals and populations. The biometric measurements were wither height (WH, brisket height (BH and ear length (EL. Thorax depth (WH-BH and the three indices, TD/WH, EL/TD and EL/WH, were also calculated. Of the seven components extracted, the first three principal components were sufficient to explain 99.5% of the total variance of the data. Graphical dispersion by genetic groups revealed that European dairy breeds clustered together. The Moroccan breeds were separated into two groups, one comprising the Drâa and the other the Zagora and Rhâali breeds. Whereas, on the one side, the Anglo-Nubian and undefined breeds were the closest to one another the goats of the Azul were observed to have the highest variation of all the breeds. The Anglo-Nubian and Boer breeds were similar to each other. The Nambi-type goats remained distinct from all the other populations. In general, the use of graphical representation of PCA values allowed to distinguish genetic groups.

  20. Short communication: A missense mutation in the PROP1 (prophet of Pit 1) gene affects male fertility and milk production traits in the US Holstein population.

    Science.gov (United States)

    Lan, X Y; Peñagaricano, F; DeJung, L; Weigel, K A; Khatib, H

    2013-02-01

    In previous studies, we reported significant associations of the POU1F1 pathway genes with reproduction and production traits in several dairy cattle populations. Polymorphisms in genes of this pathway were found to be associated with both female and male fertility traits in dairy cattle. The POU1F1 gene is a direct downstream target for the regulation of the prophet of Pit1 (PROP1) gene, also known as PROP paired-like homeobox 1. Interestingly, the position of PROP1 coincides with a quantitative trait locus affecting ovulation rate in cattle. Therefore, the objective of this study was to investigate whether PROP1 affects fertility and milk production traits in Holstein cattle. Using the DNA pooling sequencing approach, a missense single nucleotide polymorphism that replaces a histidine amino acid with an arginine was detected in exon 3 of PROP1. The arginine allele was found to be associated with a decrease in sire conception rate and an increase in productive life, protein yield, and net merit index in a population of 1,951 Holstein bulls. The transcription factors produced from the histidine and arginine isoforms are known to have different transcription, DNA binding, and regulation activities. As such, we propose that the association of the arginine isoform with decreased bull fertility is likely caused by reduced activity of this allele in male functions. The findings of this study suggest PROP1 polymorphisms as candidates in selection programs for fertility, health, and milk production traits in dairy cattle.

  1. Y chromosome gr/gr subdeletion is associated with lower semen quality in young men from the general Japanese population but not in fertile Japanese Men.

    Science.gov (United States)

    Sato, Youichi; Iwamoto, Teruaki; Shinka, Toshikatsu; Nozawa, Shiari; Yoshiike, Miki; Koh, Eitetsue; Kanaya, Jiro; Namiki, Mikio; Matsumiya, Kiyomi; Tsujimura, Akira; Komatsu, Kiyoshi; Itoh, Naoki; Eguchi, Jiro; Yamauchi, Aiko; Nakahori, Yutaka

    2014-06-01

    Several case-control studies have investigated whether Y chromosome haplogroups or deletions are associated with spermatogenic failure. However, the relationships between Y chromosome haplogroups or deletions and semen quality in general population have not been elucidated. In this study, we assessed relationships between Y chromosome haplogroups or deletions and semen parameters in 791 fertile Japanese men and 1221 young men from the general Japanese population. We found that the haplogroup D2 (M55 lineage) was significantly associated with lower semen parameters, especially total motile sperm count (P = 0.00051, beta = -0.097), in men from the general population but not in fertile men. In addition, we found that the gr/gr subdeletion was associated with semen quality and in particular, strongly associated with decreased sperm motility (P = 0.00041, beta = -3.14) and total motile sperm count (P = 0.00031, beta = -0.099) in men from the general population but not in fertile men. The combined analysis of fertile Japanese men and men from the general Japanese population showed that the haplogroup D2 (M55 lineage) and the gr/gr subdeletion were strongly associated with reduced sperm motility (P = 0.00056, beta = -2.71, and P = 7.7 × 10(-5), beta = -3.05, respectively) and that haplogroup O2b1 was strongly associated with elevated sperm motility (P = 0.00089, beta = 2.94). These observations add further support for the view that the gr/gr subdeletion diminishes sperm motility that consequently may result in male infertility.

  2. IN VITRO FERTILIZATION

    Directory of Open Access Journals (Sweden)

    Hadawale N. M

    2011-07-01

    Full Text Available First written document dealing with infertility may be found in the Kahoun papyrus (oldest Egyptian medical text, dated to 2200-1950 BC. The early attribution of infertility to women persisted for centuries and was often considered divine punishment.Infertility means 1 year of well-timed, unprotected intercourse without a pregnancy. The study shows about 10-15% of population is infertile. And 15-20% of couple have unexplained infertility (work-up is negative. Normally women are born with their lifetime egg supply, the Fertility initially declines at age 27.Significant decline at age 37-38. The chances of pregnancies are rare after age 44 besides this defect in female ovary, fallopian tube, uterus, and fibroid tumour causes infertility in female.Abnormality in sperm production and abnormality in sperm function causes infertility in male.To overcome the infertility egg are harvested from womens ovary and fertilized in laboratory with the sperm the embryos are then transfer into uterus known as In Vitro Fertilization.

  3. Estimation of Finite Population Mean in Multivariate Stratified Sampling under Cost Function Using Goal Programming

    Directory of Open Access Journals (Sweden)

    Atta Ullah

    2014-01-01

    Full Text Available In practical utilization of stratified random sampling scheme, the investigator meets a problem to select a sample that maximizes the precision of a finite population mean under cost constraint. An allocation of sample size becomes complicated when more than one characteristic is observed from each selected unit in a sample. In many real life situations, a linear cost function of a sample size nh is not a good approximation to actual cost of sample survey when traveling cost between selected units in a stratum is significant. In this paper, sample allocation problem in multivariate stratified random sampling with proposed cost function is formulated in integer nonlinear multiobjective mathematical programming. A solution procedure is proposed using extended lexicographic goal programming approach. A numerical example is presented to illustrate the computational details and to compare the efficiency of proposed compromise allocation.

  4. Modelling strategic interventions in a population with a total fertility rate of 8.3: a cross-sectional study of Idjwi Island, DRC

    OpenAIRE

    Thomson Dana R; Hadley Michael B; Greenough P; Castro Marcia C

    2012-01-01

    Abstract Background Idjwi, an island of approximately 220,000 people, is located in eastern DRC and functions semi-autonomously under the governance of two kings (mwamis). At more than 8 live births per woman, Idjwi has one of the highest total fertility rates (TFRs) in the world. Rapid population growth has led to widespread environmental degradation and food insecurity. Meanwhile family planning services are largely unavailable. Methods At the invitation of local leaders, we conducted a rep...

  5. Modelling strategic interventions in a population with a total fertility rate of 8.3: a cross-sectional study of Idjwi Island, DRC

    OpenAIRE

    Dana R Thomson; Hadley, Michael B; Greenough, P Gregg; Castro, Marcia C

    2012-01-01

    Background: Idjwi, an island of approximately 220,000 people, is located in eastern DRC and functions semi-autonomously under the governance of two kings (mwamis). At more than 8 live births per woman, Idjwi has one of the highest total fertility rates (TFRs) in the world. Rapid population growth has led to widespread environmental degradation and food insecurity. Meanwhile family planning services are largely unavailable.\\ud \\ud Methods: At the invitation of local leaders, we conducted a rep...

  6. Mean values of Arnett's soft tissue analysis in Maratha ethnic (Indian) population — A cephalometric study

    Science.gov (United States)

    Singh, Shikha; Deshmukh, Sonali; Merani, Varsha; Rejintal, Neeta

    2016-01-01

    Aim: The aim of this article is to evaluate the mean cephalometric values for Arnett's soft tissue analysis in the Maratha ethnic (Indian) population. Materials and Methods: Lateral cephalograms of 60 patients (30 males and 30 females) aged 18–26 years were obtained with the patients in the Natural Head Position (NHP), with teeth in maximum intercuspation and lips in the rest position. Moreover, hand tracings were also done. The statistical analysis was performed with the help of a statistical software, the Statistical Package for the Social Sciences version 16, and Microsoft word and Excel (Microsoft office 2007) were used to generate the analytical data. Results: Statistical significance was tested atP level (1% and 5% level of significance). Statistical analysis using student's unpaired t-test were performed. Various cephalometric values for the Maratha ethnic (Indian) population differed from Caucasian cephalometric values such as nasolabial inclination, incisor proclination, and exposure, which may affect the outcome of the orthodontic and orthognathic treatment. Conclusion: Marathas have more proclined maxillary incisors, less prominent chin, less facial length, acute nasolabial angle, and all soft tissue thickness are greater in Marathas except lower lip thickness (in Maratha males and females) and upper lip angle (in Maratha males) than those of the Caucasian population. It is a fact that all different ethnic races have different facial characters. The variability of the soft tissue integument in people with different ethnic origin makes it necessary to study the soft tissue standards of a particular community and consider those norms when planning an orthodontic and orthognathic treatment for particular racial and ethnic patients. PMID:27583221

  7. Subjective Wellbeing, Psychological needs, Meaning in life, Religious Practice and Income in the Population of Algeria

    Directory of Open Access Journals (Sweden)

    HABIB TILIOUINE

    2012-12-01

    Full Text Available e present study investigated the relationship between Subjective Wellbeing (Satisfaction with life (SWL, Personal WellbeingIndex (PWI, Positive Aect (PA and Negative Aect (NA, Psychological needs (Autonomy, Competence and Relatedness,Meaning in Life, and Religious Practice. It examined the distributions of these constructs in a large sample of 3,173 subjects(1,638 males and 1,535 females who participated in the 4th Algerian Wellbeing Survey. It aimed also to weigh up to whatextent they were aected by household income. Finally, it estimated the mediating eect of demographic variables (gender, age,education and location in the contribution of the studied constructs in each other.e results indicated that these constructs were signicantly inter-correlated and almost similarly distributed in this population.ey also showed that they were all negatively aected by low incomes and proved that generally and beyond demographic factors,SWB measures predict better needs satisfaction, meaning in life and religiosity than the opposite direction. e results werediscussed on the light of previous international wellbeing research.

  8. A NEW MODIFIED RATIO ESTIMATOR FOR ESTIMATION OF POPULATION MEAN WHEN MEDIAN OF THE AUXILIARY VARIABLE IS KNOWN

    Directory of Open Access Journals (Sweden)

    Jambulingam Subramani

    2013-10-01

    Full Text Available The present paper deals with a modified ratio estimator for estimation of population mean of the study variable when the population median of the auxiliary variable is known. The bias and mean squared error of the proposed estimator are derived and are compared with that of existing modified ratio estimators for certain known populations. Further we have also derived the conditions for which the proposed estimator performs better than the existing modified ratio estimators. From the numerical study it is also observed that the proposed modified ratio estimator performs better than the existing modified ratio estimators for certain known populations.

  9. CORRELATION OF MEAN PLATELET VOLUME IN PATIENTS WITH CARDIAC SYNDROME X IN INDIAN POPULATION

    Directory of Open Access Journals (Sweden)

    Ram Anil Raj

    2016-08-01

    matched individuals (23 men and 22 women with mean age of 45+4.5 years who presented with chest pain, normal coronaries and no ischaemia during treadmill exercise testing. RESULTS The primary characteristics of the study population are given in Table 1. There was no statistical significance between the three groups with respect to age, sex, smoking or alcohol consumption (p = NS. There were no statistically significant differences in the MPV measurements between the cardiac syndrome X group and CAD groups. (Mean MPV 12.2+1.4 fL vs. 13.8+2.1 fL, p=NS. The MPV was significantly higher in both Cardiac syndrome X (mean = 12.2+1.4 fL and CAD group (mean = 13.8+2.1 fL compared with the control groups (mean = 7.9+1.1 fL (p <0.01. CONCLUSION Elevated MPVs may participate in the pathogenesis of Cardiac Syndrome X. Prospective, placebo-controlled studies with large sample sizes that use multivariable survival analyses and long-term follow-up periods are required for the clinical evaluation of the prognostic value of increased MPV in patients with Cardiac Syndrome X.

  10. Is Wildlife Fertility Control Always Humane?

    Science.gov (United States)

    Hampton, Jordan O.; Hyndman, Timothy H.; Barnes, Anne; Collins, Teresa

    2015-01-01

    Simple Summary There are various fertility control methods (modalities) currently available that aim to reduce the abundance of problematic free-ranging mammalian wildlife. Here, we propose that dissimilarities in the mechanism of action indicate these methods produce great variation in animal welfare outcomes. We present a framework to assist managers in minimising animal welfare risks. Abstract Investigation of fertility control techniques to reduce reproductive rates in wildlife populations has been the source of much research. Techniques targeting wildlife fertility have been diverse. Most research into fertility control methods has focused upon efficacy, with few studies rigorously assessing animal welfare beyond opportunistic anecdote. However, fertility control techniques represent several very different mechanisms of action (modalities), each with their own different animal welfare risks. We provide a review of the mechanisms of action for fertility control methods, and consider the role of manipulation of reproductive hormones (“endocrine suppression”) for the long-term ability of animals to behave normally. We consider the potential welfare costs of animal manipulation techniques that are required to administer fertility treatments, including capture, restraint, surgery and drug delivery, and the requirement for repeated administration within the lifetime of an animal. We challenge the assumption that fertility control modalities generate similar and desirable animal welfare outcomes, and we argue that knowledge of reproductive physiology and behaviour should be more adeptly applied to wild animal management decisions. We encourage wildlife managers to carefully assess long-term behavioural risks, associated animal handling techniques, and the importance of positive welfare states when selecting fertility control methods as a means of population control. PMID:26506395

  11. SUHARTO’S POPULATION POLICY IN CONTEMPORARY INDONESIA : FAMILY PLANNING PROGRAM, MARRIAGE ACT OR COMPULSORY EDUCATION HAS THE GREATEST IMPACT TO FERTILITY DECLINE?

    Directory of Open Access Journals (Sweden)

    Dyah Anantalia Widyastari

    2016-05-01

    Full Text Available Fertility in Indonesia has been falling significantly, from an average total fertility rate of 5.6 children per women in 1970s to 4.1 in 1980, and 2.6 in 2010. This paper attempts to explore which and how Suharto’s population policies have played role in Indonesia’s fertility decline. Whilst the adoption of modern contraceptive was perceived as the major determinant of fertility decline in Indonesia, changes in Indonesia’s political order and socio-economic development also contribute a considerable effect to Indonesians’ familial norms. The implementation of 9-year compulsory education had placed a strong foundation for the future Indonesian human capital and enabled women to obtain higher opportunities for schooling. Beside facilitates the diffusion of ideas among young people and opened up their perspective toward reproductive rights and self actualization, education also increases women’s opportunities to participate in laborforce. With the increasing roles outside the domestic sector, delaying age of marriage and limiting family size becomes a choice for women in contemporary Indonesia. The marriage act, however, was perceived as an accelerator rather than a predictor in increasing age of first marriage. Regardless the existence of the Marriage Law 1974, age of first marriage is likely to increase with increasing of education, although maybe in a slower rate.

  12. Inferring statistics of planet populations by means of automated microlensing searches

    CERN Document Server

    Dominik, M; Horne, K; Tsapras, Y; Street, R A; Wyrzykowski, L; Hessman, F V; Hundertmark, M; Rahvar, S; Wambsganss, J; Scarpetta, G; Bozza, V; Novati, S Calchi; Mancini, L; Masi, G; Teuber, J; Hinse, T C; Steele, I A; Burgdorf, M J; Kane, S

    2008-01-01

    (abridged) The study of other worlds is key to understanding our own, and not only provides clues to the origin of our civilization, but also looks into its future. Rather than in identifying nearby systems and learning about their individual properties, the main value of the technique of gravitational microlensing is in obtaining the statistics of planetary populations within the Milky Way and beyond. Only the complementarity of different techniques currently employed promises to yield a complete picture of planet formation that has sufficient predictive power to let us understand how habitable worlds like ours evolve, and how abundant such systems are in the Universe. A cooperative three-step strategy of survey, follow-up, and anomaly monitoring of microlensing targets, realized by means of an automated expert system and a network of ground-based telescopes is ready right now to be used to obtain a first census of cool planets with masses reaching even below that of Earth orbiting K and M dwarfs in two dist...

  13. MHC-dependent survival in a wild population : evidence for hidden genetic benefits gained through extra-pair fertilizations

    NARCIS (Netherlands)

    Brouwer, Lyanne; Barr, Iain; van de Pol, Martijn; Burke, Terry; Komdeur, Jan; Richardson, David S.

    Females should prefer to be fertilized by males that increase the genetic quality of their offspring. In vertebrates, genes of the major histocompatibility complex (MHC) play a key role in the acquired immune response and have been shown to affect mating preferences. They are therefore important

  14. Mapping QTLs for Fertility Restoration of Different Cytoplasmic Male Sterility Types in Rice Using Two Oryza sativa ×O. rufipogon Backcross Inbred Line Populations

    Directory of Open Access Journals (Sweden)

    Biao-lin Hu

    2016-01-01

    Full Text Available Hybrid rice breeding using cytoplasmic male sterility/fertility restoration (CMS/Rf systems plays an important role in ensuring global food security. Two backcross inbred line (BIL populations derived from either Xieqingzao B (XB//XB/Dongxiang wild rice (DWR (XXD or XB//DWR/XB (XDX were used to detect quantitative trait loci (QTLs for fertility restoration of Dwarf wild abortive- (DA-, Indonesia Paddy- (ID-, and DWR-type CMS in rice. Lines with ID- and DA-type CMS were testcrossed with both the XXD- and XDX-BILs, while the line with DWR-type CMS was testcrossed with the XDX-BILs only. A total of 16 QTLs for fertility restoration of CMS systems were identified, including three for DWR-type CMS, six for DA-type CMS, and seven for ID-type CMS. All of the additive alleles in the QTLs were derived from Oryza rufipogon. Eleven QTLs were clustered in five chromosomal regions, indicating that common Rf loci restored different CMS systems, and the favorable O. rufipogon alleles could be used to develop restorer lines for various CMS types by marker-assisted selection.

  15. Self-emergence of Lexicon Consensus in a Population of Autonomous Agents by Means of Evolutionary Strategies

    Science.gov (United States)

    Maravall, Darío; de Lope, Javier; Domínguez, Raúl

    In Multi-agent systems, the study of language and communication is an active field of research. In this paper we present the application of evolutionary strategies to the self-emergence of a common lexicon in a population of agents. By modeling the vocabulary or lexicon of each agent as an association matrix or look-up table that maps the meanings (i.e. the objects encountered by the agents or the states of the environment itself) into symbols or signals we check whether it is possible for the population to converge in an autonomous, decentralized way to a common lexicon, so that the communication efficiency of the entire population is optimal. We have conducted several experiments, from the simplest case of a 2×2 association matrix (i.e. two meanings and two symbols) to a 3×3 lexicon case and in both cases we have attained convergence to the optimal communication system by means of evolutionary strategies. To analyze the convergence of the population of agents we have defined the population's consensus when all the agents (i.e. the 100% of the population) share the same association matrix or lexicon. As a general conclusion we have shown that evolutionary strategies are powerful enough optimizers to guarantee the convergence to lexicon consensus in a population of autonomous agents.

  16. Life-history theory, fertility and reproductive success in humans.

    Science.gov (United States)

    Strassmann, Beverly I; Gillespie, Brenda

    2002-03-22

    According to life-history theory, any organism that maximizes fitness will face a trade-off between female fertility and offspring survivorship. This trade-off has been demonstrated in a variety of species, but explicit tests in humans have found a positive linear relationship between fitness and fertility. The failure to demonstrate a maximum beyond which additional births cease to enhance fitness is potentially at odds with the view that human fertility behaviour is currently adaptive. Here we report, to our knowledge, the first clear evidence for the predicted nonlinear relationship between female fertility and reproductive success in a human population, the Dogon of Mali, West Africa. The predicted maximum reproductive success of 4.1+/-0.3 surviving offspring was attained at a fertility of 10.5 births. Eighty-three per cent of the women achieved a lifetime fertility level (7-13 births) for which the predicted mean reproductive success was within the confidence limits (3.4 to 4.8) for reproductive success at the optimal fertility level. Child mortality, rather than fertility, was the primary determinant of fitness. Since the Dogon people are farmers, our results do not support the assumptions that: (i) contemporary foragers behave more adaptively than agriculturalists, and (ii) that adaptive fertility behaviour ceased with the Neolithic revolution some 9000 years ago. We also present a new method that avoids common biases in measures of reproductive success.

  17. Humic Fertilizer and Vermicompost Applied to the Soil Can Positively Affect Population Growth Parameters of Trichogramma brassicae (Hymenoptera: Trichogrammatidae) on Eggs of Tuta absoluta (Lepidoptera: Gelechiidae)

    National Research Council Canada - National Science Library

    Mohamadi, P; Razmjou, J; Naseri, B; Hassanpour, M

    2017-01-01

    .... Interactions between natural enemies and insect pests may be affected by application of fertilizers, because changes in plant quality through the fertilizer application may therefore affect herbivore...

  18. Climate-driven vital rates do not always mean climate-driven population.

    Science.gov (United States)

    Tavecchia, Giacomo; Tenan, Simone; Pradel, Roger; Igual, José-Manuel; Genovart, Meritxell; Oro, Daniel

    2016-12-01

    Current climatic changes have increased the need to forecast population responses to climate variability. A common approach to address this question is through models that project current population state using the functional relationship between demographic rates and climatic variables. We argue that this approach can lead to erroneous conclusions when interpopulation dispersal is not considered. We found that immigration can release the population from climate-driven trajectories even when local vital rates are climate dependent. We illustrated this using individual-based data on a trans-equatorial migratory seabird, the Scopoli's shearwater Calonectris diomedea, in which the variation of vital rates has been associated with large-scale climatic indices. We compared the population annual growth rate λi , estimated using local climate-driven parameters with ρi , a population growth rate directly estimated from individual information and that accounts for immigration. While λi varied as a function of climatic variables, reflecting the climate-dependent parameters, ρi did not, indicating that dispersal decouples the relationship between population growth and climate variables from that between climatic variables and vital rates. Our results suggest caution when assessing demographic effects of climatic variability especially in open populations for very mobile organisms such as fish, marine mammals, bats, or birds. When a population model cannot be validated or it is not detailed enough, ignoring immigration might lead to misleading climate-driven projections. © 2016 John Wiley & Sons Ltd.

  19. [Effects of returning straw to soil and different tillage methods on paddy field soil fertility and microbial population].

    Science.gov (United States)

    Ren, Wan-Jun; Liu, Dai-Yin; Wu, Jin-Xiu; Wu, Ju-Xian; De, Chen-Chun; Yang, Wen-Yu

    2009-04-01

    A field experiment was conducted on a paddy field to study the effects of returning straw to soil and different tillage methods (no-tillage + returning straw, no-tillage, tillage + returning straw, and tillage) on the fertility level and microbial quantities of different soil layers. The results showed that in upper soil layer, the organic matter content in treatment 'no-tillage + returning straw' was 5.33, 2.79, and 5.37 g x kg(-1) higher than that in treatments 'no-tillage', 'tillage + returning straw', and 'tillage', respectively, and the contents of total and available N, P and K in treatment 'no-tillage + returning straw' were also the highest, followed by in treatments 'no-tillage' and 'tillage + returning straw', and in treatment 'tillage'. In deeper soil layer, all the fertility indices were higher in treatment 'tillage + returning straw'. Treatments of 'returning straw to soil' had the highest quantities of soil microbes. The quantities of bacteria, fungi, and actinomycetes in upper soil layer were the highest in treatment 'no-tillage + returning straw', and thus, the cellulose decomposition intensity in this treatment at maturity period was 26.44%, 79.01%, and 98. 15% higher than that in treatments 'tillage + returning straw', 'no-tillage', and 'tillage', respectively. In deeper soil layer, the quantities of bacteria, fungi, and actinomycetes were the highest in treatment 'tillage + returning straw'. Treatment 'no-tillage + returning straw' had the features of high fertility and abundant microbes in surface soil layer. The quantities of soil bacteria and actinomycetes and the decomposition intensity of soil cellulose were significantly positively correlated with soil fertility level.

  20. Fertility decline in Paraguay.

    Science.gov (United States)

    Ishida, Kanako; Stupp, Paul; Melian, Mercedes

    2009-09-01

    Recent reproductive health surveys show that the fertility rate in Paraguay decreased precipitously from 4.3 lifetime births per woman in 1995-98 to 2.9 births in 2001-04. In this study, we establish data consistency between the 1998 and 2004 surveys by comparing a series of cohort-specific period rates and use the Bongaarts framework of proximate determinants of fertility to demonstrate that an increase in the contraceptive prevalence rate (CPR) between 1998 and 2004 fully accounts for the fertility decline. Decomposition of rates shows that changes in group-specific CPRs explain a greater proportion of the change in the overall CPR than do changes in population composition by educational attainment, urban residence, region, and language spoken at home. Finally, we show that younger cohorts of women in 2004 reported ideal completed fertility desires of less than 2.9 births, suggesting that the fertility rate is likely to continue to decrease.

  1. Genetic make up and structure of Colombian populations by means of uniparental and biparental DNA markers.

    Science.gov (United States)

    Rojas, Winston; Parra, María Victoria; Campo, Omer; Caro, María Antonieta; Lopera, Juan Guillermo; Arias, William; Duque, Constanza; Naranjo, Andrés; García, Jharley; Vergara, Candelaria; Lopera, Jaime; Hernandez, Erick; Valencia, Ana; Caicedo, Yuri; Cuartas, Mauricio; Gutiérrez, Javier; López, Sergio; Ruiz-Linares, Andrés; Bedoya, Gabriel

    2010-09-01

    Colombia is a country with great geographic heterogeneity and marked regional differences in pre-Columbian native population density and in the extent of past African and European immigration. As a result, Colombia has one of the most diverse populations in Latin America. Here we evaluated ancestry in over 1,700 individuals from 24 Colombian populations using biparental (autosomal and X-Chromosome), maternal (mtDNA), and paternal (Y-chromosome) markers. Autosomal ancestry varies markedly both within and between regions, confirming the great genetic diversity of the Colombian population. The X-chromosome, mtDNA, and Y-chromosome data indicate that there is a pattern across regions indicative of admixture involving predominantly Native American women and European and African men.

  2. Fertility Awareness

    Science.gov (United States)

    ... I Help Someone Who's Being Bullied? Volunteering Fertility Awareness KidsHealth > For Teens > Fertility Awareness Print A A A What's in this article? ... español Monitoreo de fertilidad What Is It? Fertility awareness is a way to prevent pregnancy by not ...

  3. Chinese culture and fertility decline.

    Science.gov (United States)

    Wu, C; Jia, S

    1992-01-01

    Coale has suggested that cultural factors exert a significant influence on fertility reduction; countries in the "Chinese cultural circle" would be the first to show fertility decline. In China, the view was that traditional Chinese culture contributed to increased population. This paper examines the nature of the relationship between Chinese culture and fertility. Attention was directed to a comparison of fertility rates of developing countries with strong Chinese cultural influence and of fertility within different regions of China. Discussion was followed by an explanation of the theoretical impact of Chinese culture on fertility and direct and indirect beliefs and practices that might either enhance or hinder fertility decline. Emigration to neighboring countries occurred after the Qing dynasty. Fertility after the 1950s declined markedly in Japan, Singapore, Hong Kong, South Korea, Taiwan, and mainland China: all countries within the Chinese cultural circle. Other countries within the Chinese circle which have higher fertility, yet lower fertility than other non-Chinese cultural countries, are Malaysia, Thailand, and Indonesia. Within China, regions with similar fertility patterns are identified as coastal regions, central plains, and mountainous and plateau regions. The Han ethnic group has lower fertility than that of ethnic minorities; regions with large Han populations have lower fertility. Overseas Chinese in East Asian countries also tend to have lower fertility than their host populations. Chinese culture consisted of the assimilation of other cultures over 5000 years. Fertility decline was dependent on the population's desire to limit reproduction, favorable social mechanisms, and availability of contraception: all factors related to economic development. Chinese culture affects fertility reduction by affecting reproductive views and social mechanisms directly, and indirectly through economics. Confucianism emphasizes collectivism, self

  4. Effect of urea fertilizer application on soluble protein and free amino acid content of cotton petioles in relation to silverleaf whitefly (Bemisia argentifolii) populations.

    Science.gov (United States)

    Bi, J L; Toscano, N C; Madore, M A

    2003-03-01

    The impact of urea nitrogen fertilization on silverleaf whitefly, Bemisia argentifolii Bellows & Perring, population dynamics was examined in field-grown cotton (Gossypium hirsutum L.). Five urea nitrogen treatments were tested, consisting of soil applications of 0, 112, 168, and 224 kg nitrogen per hectare, and acombined soil-foliar application of 112:17 kg nitrogen per hectare. A positive response was observed between N application rates and the measured levels of nitrate N in petioles from mature cotton leaves. Similarly, a positive response was observed between N application rates and the numbers of adult and immature whiteflies appearing during population peaks. To determine whether these positive responses were related, we measured the levels of dietary N compounds (proteins and free amino acids) that would be available for insect nutrition in cotton petioles at the different N application rates. Sampling dates and N application treatments affected levels of soluble proteins in cotton petioles, and interactions between sampling dates and treatments were significant. Across all sampling dates, the relationship between N application rates and levels of soluble proteins was linear. Sampling dates also affected levels of total and individual free amino acids. Fertilizer treatments only affected levels of total amino acids, aspartate, asparagine, and arginine plus threonine. Levels of aspartate or asparagine and the N application rates were linearly correlated. No significant correlations were observed between levels of dietary N compounds in cotton petioles and numbers of whiteflies, either adults or immatures, on the cotton plants.

  5. Stochastic multi-scale models of competition within heterogeneous cellular populations: Simulation methods and mean-field analysis.

    Science.gov (United States)

    Cruz, Roberto de la; Guerrero, Pilar; Spill, Fabian; Alarcón, Tomás

    2016-10-21

    We propose a modelling framework to analyse the stochastic behaviour of heterogeneous, multi-scale cellular populations. We illustrate our methodology with a particular example in which we study a population with an oxygen-regulated proliferation rate. Our formulation is based on an age-dependent stochastic process. Cells within the population are characterised by their age (i.e. time elapsed since they were born). The age-dependent (oxygen-regulated) birth rate is given by a stochastic model of oxygen-dependent cell cycle progression. Once the birth rate is determined, we formulate an age-dependent birth-and-death process, which dictates the time evolution of the cell population. The population is under a feedback loop which controls its steady state size (carrying capacity): cells consume oxygen which in turn fuels cell proliferation. We show that our stochastic model of cell cycle progression allows for heterogeneity within the cell population induced by stochastic effects. Such heterogeneous behaviour is reflected in variations in the proliferation rate. Within this set-up, we have established three main results. First, we have shown that the age to the G1/S transition, which essentially determines the birth rate, exhibits a remarkably simple scaling behaviour. Besides the fact that this simple behaviour emerges from a rather complex model, this allows for a huge simplification of our numerical methodology. A further result is the observation that heterogeneous populations undergo an internal process of quasi-neutral competition. Finally, we investigated the effects of cell-cycle-phase dependent therapies (such as radiation therapy) on heterogeneous populations. In particular, we have studied the case in which the population contains a quiescent sub-population. Our mean-field analysis and numerical simulations confirm that, if the survival fraction of the therapy is too high, rescue of the quiescent population occurs. This gives rise to emergence of resistance

  6. A Class of Estimators for Finite Population Mean in Double Sampling under Nonresponse Using Fractional Raw Moments

    Directory of Open Access Journals (Sweden)

    Manzoor Khan

    2014-01-01

    Full Text Available This paper presents new classes of estimators in estimating the finite population mean under double sampling in the presence of nonresponse when using information on fractional raw moments. The expressions for mean square error of the proposed classes of estimators are derived up to the first degree of approximation. It is shown that a proposed class of estimators performs better than the usual mean estimator, ratio type estimators, and Singh and Kumar (2009 estimator. An empirical study is carried out to demonstrate the performance of a proposed class of estimators.

  7. Estimation of Finite Population Mean in Stratified Random Sampling Using Auxiliary Attribute(s under Non-Response

    Directory of Open Access Journals (Sweden)

    Javid Shabbir

    2012-01-01

    Full Text Available In this paper we propose a combined exponential ratio type estimator of finite population mean utilizing information on the auxiliary attribute(s under non-response. Expressions for bias and MSE of the proposed estimator are derived up to first order of approximation. An empirical study is carried out to observe the performances of the estimators.

  8. Constraining the GRB-magnetar model by means of the Galactic pulsar population

    CERN Document Server

    Rea, Nanda; Pons, Jose' A; Perna, Rosalba; Dainotti, Maria G; Miralles, Juan A; Torres, Diego F

    2015-01-01

    A large fraction of Gamma Ray Bursts (GRBs) displays an X-ray plateau phase within <10^{5} s from the prompt emission, proposed to be powered by the spin-down energy of a rapidly spinning newly born magnetar. In this work we use the properties of the Galactic neutron star population to constrain the GRB-magnetar scenario. We re-analyze the X-ray plateaus of all Swift GRBs with known redshift, between January 2005 and August 2014. From the derived initial magnetic field distribution for the possible magnetars left behind by the GRBs, we study the evolution and properties of a simulated GRB-magnetar population using numerical simulations of magnetic field evolution, coupled with Monte Carlo simulations of Pulsar Population Synthesis in our Galaxy. We find that if the GRB X-ray plateaus are powered by the rotational energy of a newly formed magnetar, the current observational properties of the Galactic magnetar population are not compatible with being formed within the GRB scenario (regardless of the GRB type...

  9. Teaching Population Ecology Modeling by Means of the Hewlett-Packard 9100A.

    Science.gov (United States)

    Tuinstra, Kenneth E.

    The incorporation of mathematical modeling experiences into an undergraduate biology course is described. Detailed expositions of three models used to teach concepts of population ecology are presented, including introductions to major concepts, user instructions, trial data and problem sets. The models described are: 1) an exponential/logistic…

  10. Constraining the GRB-Magnetar Model by Means of the Galactic Pulsar Population

    NARCIS (Netherlands)

    N. Rea; M. Gullón; J.A. Pons; R. Perna; M.G. Dainotti; J.A. Miralles; D.F. Torres

    2015-01-01

    A large fraction of Gamma-ray bursts (GRBs) displays an X-ray plateau phase within <105 s from the prompt emission, proposed to be powered by the spin-down energy of a rapidly spinning newly born magnetar. In this work we use the properties of the Galactic neutron star population to constrain the GR

  11. On Reverse Stackelberg Game and Optimal Mean Field Control for a Large Population of Thermostatically Controlled Loads

    Energy Technology Data Exchange (ETDEWEB)

    Li, Sen; Zhang, Wei; Lian, Jianming; Kalsi, Karanjit

    2016-07-08

    This paper studies a multi-stage pricing problem for a large population of thermostatically controlled loads. The problem is formulated as a reverse Stackelberg game that involves a mean field game in the hierarchy of decision making. In particular, in the higher level, a coordinator needs to design a pricing function to motivate individual agents to maximize the social welfare. In the lower level, the individual utility maximization problem of each agent forms a mean field game coupled through the pricing function that depends on the average of the population control/state. We derive the solution to the reverse Stackelberg game by connecting it to a team problem and the competitive equilibrium, and we show that this solution corresponds to the optimal mean field control that maximizes the social welfare. Realistic simulations are presented to validate the proposed methods.

  12. Libraries as a means for the integration of immigrant populations in Ávila province

    Directory of Open Access Journals (Sweden)

    María Jesús Romera Iruela

    2014-11-01

    Full Text Available Public libraries can be considered as suitable agents and places for the integration of immigrant population. Therefore, services and programs should be developed in order to give an adequate answer to their needs. This article provides some research findings for the information needs of immigrants at Ávila province. These needs are detected from three different perspectives: public libraries, educational centers, and immigrant associations. The data were collected, using ad-hoc questionnaires, in the districts and municipalities with largest immigrant presence. Several intercultural actions directed to the integration of this population are suggested in this research. Thus, amongst others, the need of a Web site with thematic information on the design of cooperative programs on intercultural education between public libraries and scholar libraries, involving both parents of immigrant students and immigrants associations

  13. CONSTRAINING THE GRB-MAGNETAR MODEL BY MEANS OF THE GALACTIC PULSAR POPULATION

    Energy Technology Data Exchange (ETDEWEB)

    Rea, N. [Anton Pannekoek Institute for Astronomy, University of Amsterdam, Postbus 94249, NL-1090 GE Amsterdam (Netherlands); Gullón, M.; Pons, J. A.; Miralles, J. A. [Departament de Fisica Aplicada, Universitat d’Alacant, Ap. Correus 99, E-03080 Alacant (Spain); Perna, R. [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States); Dainotti, M. G. [Physics Department, Stanford University, Via Pueblo Mall 382, Stanford, CA (United States); Torres, D. F. [Instituto de Ciencias de l’Espacio (ICE, CSIC-IEEC), Campus UAB, Carrer Can Magrans s/n, E-08193 Barcelona (Spain)

    2015-11-10

    A large fraction of Gamma-ray bursts (GRBs) displays an X-ray plateau phase within <10{sup 5} s from the prompt emission, proposed to be powered by the spin-down energy of a rapidly spinning newly born magnetar. In this work we use the properties of the Galactic neutron star population to constrain the GRB-magnetar scenario. We re-analyze the X-ray plateaus of all Swift GRBs with known redshift, between 2005 January and 2014 August. From the derived initial magnetic field distribution for the possible magnetars left behind by the GRBs, we study the evolution and properties of a simulated GRB-magnetar population using numerical simulations of magnetic field evolution, coupled with Monte Carlo simulations of Pulsar Population Synthesis in our Galaxy. We find that if the GRB X-ray plateaus are powered by the rotational energy of a newly formed magnetar, the current observational properties of the Galactic magnetar population are not compatible with being formed within the GRB scenario (regardless of the GRB type or rate at z = 0). Direct consequences would be that we should allow the existence of magnetars and “super-magnetars” having different progenitors, and that Type Ib/c SNe related to Long GRBs form systematically neutron stars with higher initial magnetic fields. We put an upper limit of ≤16 “super-magnetars” formed by a GRB in our Galaxy in the past Myr (at 99% c.l.). This limit is somewhat smaller than what is roughly expected from Long GRB rates, although the very large uncertainties do not allow us to draw strong conclusion in this respect.

  14. Modelling strategic interventions in a population with a total fertility rate of 8.3: a cross-sectional study of Idjwi Island, DRC

    Directory of Open Access Journals (Sweden)

    Thomson Dana R

    2012-11-01

    Full Text Available Abstract Background Idjwi, an island of approximately 220,000 people, is located in eastern DRC and functions semi-autonomously under the governance of two kings (mwamis. At more than 8 live births per woman, Idjwi has one of the highest total fertility rates (TFRs in the world. Rapid population growth has led to widespread environmental degradation and food insecurity. Meanwhile family planning services are largely unavailable. Methods At the invitation of local leaders, we conducted a representative survey of 2,078 households in accordance with MEASURE DHS protocols, and performed ethnographic interviews and focus groups with key informants and vulnerable subpopulations. Modelling proximate determinates of fertility, we evaluated how the introduction of contraceptives and/or extended periods of breastfeeding could reduce the TFR. Results Over half of all women reported an unmet need for spacing or limiting births, and nearly 70% named a specific modern method of contraception they would prefer to use; pills (25.4% and injectables (26.5% were most desired. We predicted that an increased length of breastfeeding (from 10 to 21 months or an increase in contraceptive prevalence (from 1% to 30%, or a combination of both could reduce TFR on Idjwi to 6, the average desired number of children. Increasing contraceptive prevalence to 15% could reduce unmet need for contraception by 8%. Conclusions To meet women’s need and desire for fertility control, we recommend adding family planning services at health centers with NGO support, pursuing a community health worker program, promoting extended breastfeeding, and implementing programs to end sexual- and gender-based violence toward women.

  15. Biological organic fertilizer effect on population succession of phytoplankton%生物有机肥对浮游植物种群演替的影响

    Institute of Scientific and Technical Information of China (English)

    陶志英; 熊宗辉; 刘大伟; 文春根; 胡宝庆; 万会平

    2013-01-01

    通过在水体中施用生物有机肥,观察水体中浮游植物群落的变化.结果共观察到浮游植物8门93属185种.叶绿素a的含量和生物密度随着施肥量的增加呈上升趋势,充氧与不充氧组之间差异不显著(P>0.05);当施肥量为0.24 g·L-1,水温25℃时,叶绿素a含量最高,为119.24 ug·L-1,并且生物密度最大,为5.15×107 cells/L;充氧施肥量为0.06 g·L-1时,生物密度达到最大,为3.81×107 cells/L;不充氧施肥量达0.48 g·L-1时,生物密度达到最大,为3.97×107 cells/L;充氧与不充氧组之间没有显著的差异(P>0.05).施肥前多样性指数为2.08,施肥量至0.24 g·L-1时,充氧条件下多样性指数最高,为2.69;水温25℃时,多样性指数最高,为2.74.未施肥时,只有肘状针杆藻和硬弓形藻2个优势种,而施肥后先后共出现17个优势种;其中绿藻门,蓝藻门中的最多,绿藻门有7个,蓝藻门有6个;施肥量相同时,充氧组的优势种数量明显多于不充氧组;黄藻门和隐藻门的种类只有在充氧条件下才成为优势种.当施肥量恒定为0.24 g·L-1时,不同温度下先后共出现12个优势种,其中绿藻门,蓝藻门中的优势种最多,均有5个优势种;随温度上升,优势种的数量逐渐减少.%Biological organic fertilizer was utilized in natural water to study the change of the population of phytoplankton. 8 Phylum,93 genera and 185 species of phytoplankton were observed. With the increase of fertilizer, content of chlorophyll a and biological density showed uptrend. There was no significant difference between complementary oxygenated and non-oxygenated (P>0. 05). When fertilizer rate constant was 0. 24 g· L-1 with 25℃ of water temperature, the content of chlorophyll was the highest to 119. 24 ug · L-1 and the largest biological density was 5. 15X107 cells/L. Under complementary oxygenated condition, fertilizer rate was 0. 06 g · L-1, biological density with 3. 81 × 107 cells/L was

  16. Reflections on fertility dynamics in Romania.

    Science.gov (United States)

    Bratu, Eugenia Claudia; Minca, Dana Galieta

    2012-01-01

    Aims to highlight the changes occurred in the evolution of the fertility phenomenon in Romania, focusing on developments in the general fertility rate, total fertility rate, number of live births, and on the construction of specific indicators to reveal the source of demographic change. Several theories on the factors that may cause fertility decline it were outlined, underlining the presence of these factors during fertility dynamics in our country. After 1990, population decline may be explained by a close inter-relationship between economic theories (worsening economic conditions lead to decreased fertility) and the second demographic transition (postponement of births, fertility change model).

  17. Study on chromatic aberration in a population of Chinese myopic eyes by means of optical design.

    Science.gov (United States)

    He, Yuanqing; Wang, Yan; Wang, Zhaoqi; Fang, Chao; Liu, Yongji; Zhang, Lin; Zheng, Shaolin; Wang, Lu; Chang, Shengjiang

    2013-05-01

    Two kinds of individual eye models, involving and without involving the angle between visual axis and optical axis, are established by means of optical design. We use them to study the properties of the transverse chromatic aberration (TCA) and longitudinal chromatic aberration (LCA) over the visible spectrum. Then the effects of the LCA and TCA on the visual quality of human eyes are evaluated. The statistical averages of TCA and LCA over the visible spectrum for Chinese myopic eyes are obtained. Results show that both TCA and LCA restrict the visual performance, and LCA is more detrimental than TCA.

  18. A note on a difference-type estimator for population mean under two-phase sampling design.

    Science.gov (United States)

    Khan, Mursala; Al-Hossain, Abdullah Yahia

    2016-01-01

    In this manuscript, we have proposed a difference-type estimator for population mean under two-phase sampling scheme using two auxiliary variables. The properties and the mean square error of the proposed estimator are derived up to first order of approximation; we have also found some efficiency comparison conditions for the proposed estimator in comparison with the other existing estimators under which the proposed estimator performed better than the other relevant existing estimators. We show that the proposed estimator is more efficient than other available estimators under the two phase sampling scheme for this one example; however, further study is needed to establish the superiority of the proposed estimator for other populations.

  19. Does multiple hosts mean multiple parasites? Population genetic structure of Schistosoma japonicum between definitive host species.

    Science.gov (United States)

    Wang, T P; Shrivastava, J; Johansen, M V; Zhang, S Q; Wang, F F; Webster, J P

    2006-10-01

    Multi-host parasites, those capable of infecting more than one species of host, are responsible for the majority of all zoonotic, emerging or persistent human and animal diseases and are considered one of the major challenges for the biomedical sciences in the 21st century. We characterized the population structure of the multi-host parasite Schistosoma japonicum in relation to its definitive host species by genotyping miracidia collected from humans and domestic animals across five villages around the Yangtze River in Anhui Province, mainland China, using microsatellite markers. High levels of polymorphisms were observed and two main genetic clusters were identified which separated water buffalo, cattle and humans from goats, pigs, dogs and cats. We thereby believe that we present the first evidence of definitive host-based genetic variation in Schistosoma japonicum which has important epidemiological, evolutionary, medical and veterinary implications.

  20. Social patterns and differentials in the fertility transition in the context of HIV/AIDS: evidence from population surveillance, rural South Africa, 1993 - 2013

    National Research Council Canada - National Science Library

    Houle, Brian; Pantazis, Athena; Kabudula, Chodziwadziwa; Tollman, Stephen; Clark, Samuel J

    2016-01-01

    Literature is limited on the effects of high prevalence HIV on fertility in the absence of treatment, and the effects of the introduction of sustained access to antiretroviral therapy (ART) on fertility...

  1. Evaluation of development of three cultivars of coral bells (Heuchera after application of organic means of improving soil properties and mineral fertilizers on post-mining area of the Dąbrowskie Coal Basin

    Directory of Open Access Journals (Sweden)

    Gabriela Sąkol

    2012-12-01

    Full Text Available The present study investigated the effect of improving soil properties using a liquid organic means: Eko-użyźniacz, based on manure vermicompost, and traditional fertilizer Azofoska on three cultivars of coral bells: ‘Chatterbox’, ‘Marmelade’ and ‘Purple Petticoats’. The plants were field cultivated on post-mining area of the Dąbrowskie Coal Basin from 2009 to 2011. Even though, the doses of nutriens from mean of improve soil properties were low the plants were visually appealing. The effect of Azofoska or Eko-użyźniacz used were not significant (α = 0.05 in diameter of plants, numbers of shoots and inflorescences. All of the cultivars gave more flower shoots in the second vegetation period. Plants of coral bells grow well after a treatment of Eko-użyźniacz, which means that use of this treatment is addequate for post-mining soils.  

  2. Mean-field state population study for iron-based superconductors

    Science.gov (United States)

    Wang, Zhigang; Fu, Zhen-Guo; Zheng, Fa-Wei; Zhang, Ping

    2017-02-01

    The occupation number distribution in momentum space are theoretically studied within a two-orbital model, which can be unified describing the low-energy physics of the iron pnictides and iron chalcogenides. The mean-field approximation of Hubbard interaction is employed. By tuning the hopping parameters, the difference between the iron pnictides and iron chalcogenides in their occupation number distribution behavior can be clearly observed. The results show that when the pairing interaction tends to zero, the occupation number n (k) ≈ 0 at Γ point for iron chalcogenides while n (k) ≈ 2 at Γ point for iron pnictides. By increasing the strength of the pairing interaction to a large value, the change of n (k) at Γ point for iron chalcogenides (pnictides) is remarkable (unremarkable). In addition, we find that the effect of the nearest-neighbor coupling between the two layers, contained in the S4 model [Hu and Hao, (2012) [33

  3. Progress report 1993 : Regulation of mule deer population growth by fertility control : Laboratory, field, and simulation experiments

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — We developed analytical models to describe dynamics of the Rocky Mountain Arsenal mule population. Our objectives were: 1) To estimate carrying capacity of the...

  4. Purging deleterious mutations under self fertilization: paradoxical recovery in fitness with increasing mutation rate in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Levi T Morran

    Full Text Available BACKGROUND: The accumulation of deleterious mutations can drastically reduce population mean fitness. Self-fertilization is thought to be an effective means of purging deleterious mutations. However, widespread linkage disequilibrium generated and maintained by self-fertilization is predicted to reduce the efficacy of purging when mutations are present at multiple loci. METHODOLOGY/PRINCIPAL FINDINGS: We tested the ability of self-fertilizing populations to purge deleterious mutations at multiple loci by exposing obligately self-fertilizing populations of Caenorhabditis elegans to a range of elevated mutation rates and found that mutations accumulated, as evidenced by a reduction in mean fitness, in each population. Therefore, purging in obligate selfing populations is overwhelmed by an increase in mutation rate. Surprisingly, we also found that obligate and predominantly self-fertilizing populations exposed to very high mutation rates exhibited consistently greater fitness than those subject to lesser increases in mutation rate, which contradicts the assumption that increases in mutation rate are negatively correlated with fitness. The high levels of genetic linkage inherent in self-fertilization could drive this fitness increase. CONCLUSIONS: Compensatory mutations can be more frequent under high mutation rates and may alleviate a portion of the fitness lost due to the accumulation of deleterious mutations through epistatic interactions with deleterious mutations. The prolonged maintenance of tightly linked compensatory and deleterious mutations facilitated by self-fertilization may be responsible for the fitness increase as linkage disequilibrium between the compensatory and deleterious mutations preserves their epistatic interaction.

  5. Model to Track Wild Birds for Avian Influenza by Means of Population Dynamics and Surveillance Information

    Science.gov (United States)

    Alba, Anna; Bicout, Dominique J.; Vidal, Francesc; Curcó, Antoni; Allepuz, Alberto; Napp, Sebastián; García-Bocanegra, Ignacio; Costa, Taiana; Casal, Jordi

    2012-01-01

    Design, sampling and data interpretation constitute an important challenge for wildlife surveillance of avian influenza viruses (AIV). The aim of this study was to construct a model to improve and enhance identification in both different periods and locations of avian species likely at high risk of contact with AIV in a specific wetland. This study presents an individual-based stochastic model for the Ebre Delta as an example of this appliance. Based on the Monte-Carlo method, the model simulates the dynamics of the spread of AIV among wild birds in a natural park following introduction of an infected bird. Data on wild bird species population, apparent AIV prevalence recorded in wild birds during the period of study, and ecological information on factors such as behaviour, contact rates or patterns of movements of waterfowl were incorporated as inputs of the model. From these inputs, the model predicted those species that would introduce most of AIV in different periods and those species and areas that would be at high risk as a consequence of the spread of these AIV incursions. This method can serve as a complementary tool to previous studies to optimize the allocation of the limited AI surveillance resources in a local complex ecosystem. However, this study indicates that in order to predict the evolution of the spread of AIV at the local scale, there is a need for further research on the identification of host factors involved in the interspecies transmission of AIV. PMID:22952962

  6. Model to track wild birds for avian influenza by means of population dynamics and surveillance information.

    Directory of Open Access Journals (Sweden)

    Anna Alba

    Full Text Available Design, sampling and data interpretation constitute an important challenge for wildlife surveillance of avian influenza viruses (AIV. The aim of this study was to construct a model to improve and enhance identification in both different periods and locations of avian species likely at high risk of contact with AIV in a specific wetland. This study presents an individual-based stochastic model for the Ebre Delta as an example of this appliance. Based on the Monte-Carlo method, the model simulates the dynamics of the spread of AIV among wild birds in a natural park following introduction of an infected bird. Data on wild bird species population, apparent AIV prevalence recorded in wild birds during the period of study, and ecological information on factors such as behaviour, contact rates or patterns of movements of waterfowl were incorporated as inputs of the model. From these inputs, the model predicted those species that would introduce most of AIV in different periods and those species and areas that would be at high risk as a consequence of the spread of these AIV incursions. This method can serve as a complementary tool to previous studies to optimize the allocation of the limited AI surveillance resources in a local complex ecosystem. However, this study indicates that in order to predict the evolution of the spread of AIV at the local scale, there is a need for further research on the identification of host factors involved in the interspecies transmission of AIV.

  7. Comparison between a sire model and an animal model for genetic evaluation of fertility traits in Danish Holstein population

    DEFF Research Database (Denmark)

    Sun, C; Madsen, P; Nielsen, U S

    2009-01-01

    Comparisons between a sire model, a sire-dam model, and an animal model were carried out to evaluate the ability of the models to predict breeding values of fertility traits, based on data including 471,742 records from the first lactation of Danish Holstein cows, covering insemination years from...... (EBV) from the animal model and the sire-dam model were close to 1 for all the traits, and those between the animal model and the sire model ranged from 0.95 to 0.97. Model ability to predict sire breeding value was assessed using 4 criteria: 1) the correlation between sire EBV from 2 data subsets...... (DATAA and DATAB); 2) the correlation between sire EBV from training data (DATAA or DATAB) and yield deviation from test data (DATAB or DATAA) in a cross-validation procedure; 3) the correlation between the EBV of proven bulls, obtained from the whole data set (DATAT) and from a reduced set of data...

  8. Screening Mammography: A Pilot Study on Its Pertinence in Indian Population by Means of a Camp.

    Science.gov (United States)

    Kumar, Joish Upendra; Sreekanth, Vivek; Reddy, Harikiran R; Sridhar, Aishwarya B; Kodali, Niveditha; Prabhu, Anitha S

    2017-08-01

    Breast cancer incidence and related mortality is increasing in Indian women. Indian ladies hesitate to seek medical care for breast related issues. Screening mammography, proved to effectively reduce mortality, has been deemed not feasible in Indian context due to cost considerations. The suggested alternatives have not been proven to improve mortality rates. To find the relevance of screening mammography camp among Indian women. A week long screening mammography camp was organized in a tertiary care hospital. Clinical examination was done followed by bilateral mammography. Mammograms were reported as per American College of Radiology-Breast Imaging Reporting and Data Systems (ACR-BIRADS) 5(th) edition specifications. Lesions deemed BIRADS 4 and 5 were biopsied. BIRADS 3 category findings were suggested short interval follow up. A total of 118 women, ranging from 35 to 64 years of age with mean age of 49.6 years underwent mammography. Thirty ladies with dense breast compositions further underwent sono-mammography. Six (5.1%) new cases of breast carcinomas were detected during this study and 28 (23.7%) cases with probably benign findings were advised short interval follow up. Mammography, being a proven screening modality effective in reducing mortality, needs incorporation into the nationwide program for breast cancer detection, inspite of financial considerations. Organizing mammography camps will help create awareness and encourage public to utilize services.

  9. Biological and behavioral determinants of fertility in Tierra del Fuego.

    Science.gov (United States)

    Pascual, J; García-Moro, C E; Hernández, M

    2005-05-01

    The reproductive history of 182 women in postreproductive life or near menopause from the Chilean part of Tierra del Fuego was traced back by means of familial interviews. These postmenopausal women represent the population since almost the beginning of the settlement, and their reproductive years were spent on the island. Path analysis was applied to analyze fertility determinants of these women and to propose a complex model of interconnections among factors. The reproductive history of these women is characterized by a long fertile span, a short childbearing period, and low fertility. Age at menarche is relatively late, and the age of the women at first birth is mainly determined by their late age at marriage. The use of contraception is related to both spacing and stopping behaviors. The late age of women at marriage, the rhythm of conception, and practices of contraception are proposed as the main determinants of fertility in Tierra del Fuego. Copyright 2004 Wiley-Liss, Inc.

  10. Natural fertility in the Philippines.

    Science.gov (United States)

    Aquino, E G

    1982-01-01

    The hypothesis that modernization trends in the Philippines led to an increase in fecundity and natural fertility between 1953-1972 was tested, using data from the 1973 National Demographic Survey. More specifically, it was hypothesized that increases in education, income levels, urbanization, female labor force participation, and other factors exerted a positive influence on the population's health and nutritional status and increased the risk of pregnancy by diminishing the strength of sexual taboos and by decreasing the incidence of breastfeeding. These changes, in turn, had a positive impact on natural fertility. Natural fertility was defined as marital fertility in the absence of specific efforts to control fertility. The use of natural fertility instead of fecundity allowed for the influence of behavioral patterns, such as breastfeeding and sexual taboos, on fertility. Period analysis of age specific marital fertility rates for each 5 year period between 1953-72 and cohort analysis of age specific marital fertility rates for the birth cohorts, aged 55-59, 50-54, 45-49, 40-44, and 35-39 in 1973 were undertaken. The effect of fertility control was determined by using an index derived from an equation provided by Coale and Trussell. Findings of both the period and cohort analysis supported the hypothesis. Period analysis revealed that natural fertility increased between 1953-57 and 1969-72 by 10% and that the greatest increase occurred during the 1950s when Philippine society experienced major modernization changes. The increases in natural fertility were accompanied by corresponding increases in fertility regulation in each time period. These trends tended to cancel each other out and resulted in a relatively stable total marital fertility rate throughout the time period. Cohort analysis revealed that only the total marital fertility rate of the youngest cohort was influenced by fertility regulation. The level of natural fertility for all cohorts as a group

  11. The fertility decline in Kenya.

    Science.gov (United States)

    Robinson, W C; Harbison, S F

    1995-01-01

    In Sub-Saharan Africa Kenya is a prime example of a country experiencing a rapid decline in fertility and greater contraceptive prevalence. These changes have occurred since 1980 when fertility was high at 8.0 children per woman. In 1993 the total fertility rate (TFR) was 5.4, and the growth rate declined to about 2.0%. This transition is swifter than any country in contemporary Asia or historical Europe. The likely projection for Kenya is attainment of replacement level fertility during the 2020s and a leveling of population at about 100 million persons. Fertility has declined the most in urban areas and central and eastern regions. Bongaarts' proximate determinants (TFR, total marital fertility rate, total natural marital fertility rate, and total fecundity) are reduced to the proportion of currently married women using contraception, the proportion in lactational nonfecund status, and the proportion currently married. Actual fertility change is accounted for by total fertility change of 3.0 children. Lactational infecundability accounts for 0.5 potential births, and changes in marital fertility account for 1.0 reduced births per woman. About 70% of fertility reduction is accounted for by contraception and abortion. During 1977-78 80% of fertility control was due to lactational nonfecundity, 10% to nonmarriage, and 10% to contraception. In 1993 lactational nonfecundity accounted for 50% of the reduction, nonmarriage for 20%, and abortion about 30%. Future fertility is expected to be dependent on contraceptive prevalence. Kenya has experienced the Coale paradigm of preconditions necessary for demographic transition (willing, ready, and able). High fertility in Africa is not intractable. Creating the change in attitudes that leads to readiness is linked to education, health, and exposure to modernizing media and urban lifestyles. The public sector family planning program in Kenya has created the opportunity for access and availability of contraception. The key

  12. Effect of population and level of industrialization on underground ...

    African Journals Online (AJOL)

    SERVER

    2008-02-19

    Feb 19, 2008 ... case study. Underground waters of ... part of this study is to determine the effect of population and level of ... mental means were compared using the DUNCAN new multiple range test ..... Mortality of nitrate fertilizer workers.

  13. Marriage season, promptness of successful pregnancy and first-born sex ratio in a historical natural fertility population - evidence for sex-dependent early pregnancy loss?

    Science.gov (United States)

    Nonaka, K.; Desjardins, Bertrand; Charbonneau, Hubert; Légaré, Jacques; Miura, Teiji

    We investigated population-based vital records of the seventeenth and eighteenth century French Canadian population to assess the effects of marriage season on the outcome of the first births under natural fertility conditions (n=21,698 marriages). Promptness of the first successful conception after marriage differed according to marriage season; the proportion of marriages with a marriage-first birth interval of 8.0-10.0 months was lowest (34%) for marriages in August-October (P=0.001). Although the male/female sex ratio of the babies born with an interval of 8.0-10.0 months was generally higher (1.10) than those with an interval of 10.0-24.0 months (1.05), the marriages in August-October resulted in a significantly reduced sex ratio (0.96) among only the prompt conceptions (P=0.026). We discuss whether this seasonal reduction of the sex ratio could be partly explained by a clustered pregnancy loss of male zygotes in early pregnancy.

  14. Marriage season, promptness of successful pregnancy and first-born sex ratio in a historical natural fertility population--evidence for sex-dependent early pregnancy loss?

    Science.gov (United States)

    Nonaka, K; Desjardins, B; Charbonneau, H; Légaré, J; Miura, T

    1998-12-01

    We investigated population-based vital records of the seventeenth and eighteenth century French Canadian population to assess the effects of marriage season on the outcome of the first births under natural fertility conditions (n = 21,698 marriages). Promptness of the first successful conception after marriage differed according to marriage season; the proportion of marriages with a marriage-first birth interval of 8.0-10.0 months was lowest (34%) for marriages in August-October (P = 0.001). Although the male/female sex ratio of the babies born with an interval of 8.0-10.0 months was generally higher (1.10) than those with an interval of 10.0-24.0 months (1.05), the marriages in August-October resulted in a significantly reduced sex ratio (0.96) among only the prompt conceptions (P = 0.026). We discuss whether this seasonal reduction of the sex ratio could be partly explained by a clustered pregnancy loss of male zygotes in early pregnancy.

  15. Fertility Desire and Reproductive Health

    African Journals Online (AJOL)

    Understanding fertility desire and reproductive health care needs of HIV positive men and women in the era ... and related consequences. ... inform national policy decisions on PMTCT, HIV ... The study population was included proportional to.

  16. Fertility preservation for girls and young women with cancer: population-based validation of criteria for ovarian tissue cryopreservation.

    Science.gov (United States)

    Wallace, W Hamish B; Smith, Alice Grove; Kelsey, Thomas W; Edgar, Angela E; Anderson, Richard A

    2014-09-01

    Ovarian tissue cryopreservation with later reimplantation has been shown to preserve fertility in adult women, but this approach remains unproven and experimental in children and adolescents. We aimed to assess the use of the Edinburgh selection criteria for ovarian tissue cryopreservation in girls and young women with cancer to determine whether we are offering this invasive procedure to the patients who are most at risk of premature ovarian insufficiency. Cryopreservation of ovarian tissue has been selectively offered to girls and young women with cancer who met the Edinburgh selection criteria since 1996. Between Jan 1, 1996, and June 30, 2012, 410 female patients younger than 18 years at diagnosis were treated for cancer (including leukaemia and brain tumours) at the Edinburgh Children's Cancer Centre, which serves the whole South East of Scotland region. We determined the ovarian status of these patients from review of clinical records and classified them as having premature ovarian insufficiency or not, or as unable to be determined. Patients younger than 12 years at time of data cutoff (Jan 31, 2013) were excluded from the analysis. 34 (8%) of the 410 patients met the Edinburgh selection criteria and were offered ovarian tissue cryopreservation before starting cancer treatment. 13 patients declined the procedure and 21 consented, and the procedure was completed successfully in 20 patients. Of the 20 patients who had ovarian tissue successfully cryopreserved, 14 were available for assessment of ovarian function. Of the 13 patients who had declined the procedure, six were available for assessment of ovarian function. Median age at the time of follow-up for the 20 assessable patients was 16·9 years (IQR 15·5-21·8). Of the 14 assessable patients who had successfully undergone ovarian cryopreservation, six had developed premature ovarian insufficiency at a median age of 13·4 years (IQR 12·5-14·6), one of whom also had a natural pregnancy. Of the six

  17. Communication and coping as predictors of fertility problem stress: cohort study of 816 participants who did not achieve a delivery after 12 months of fertility treatment

    DEFF Research Database (Denmark)

    Schmidt, L; Holstein, B E; Christensen, Ulla

    2005-01-01

    participants (n = 816, men and women) who had not achieved pregnancy by assisted reproduction or delivery at follow-up. RESULTS: Among both men and women, difficulties in partner communication predicted high fertility problem stress (odds ratio for women, 3.47, 95% confidence interval 2.09-5.76; odds ratio......BACKGROUND: We investigated coping strategies and communication strategies as predictors of fertility problem stress 12 months after start of fertility treatment. METHODS: We used a prospective, longitudinal cohort design including 2250 people beginning fertility treatment with a 12-month follow......-up. Data were based on self-administered questionnaires measuring communication with partner and with other people, coping strategies: active-avoidance coping, active-confronting coping, passive-avoidance coping, meaning-based coping, and fertility problem stress. The study population included those...

  18. Countries population determination to test rice crisis indicator at national level using k-means cluster analysis

    Science.gov (United States)

    Hidayat, Y.; Purwandari, T.; Sukono; Ariska, Y. D.

    2017-01-01

    This study aimed to obtain information on the population of the countries which is have similarities with Indonesia based on three characteristics, that is the democratic atmosphere, rice consumption and purchasing power of rice. It is useful as a reference material for research which tested the strength and predictability of the rice crisis indicators Unprecedented Restlessness (UR). The similarities countries with Indonesia were conducted using multivariate analysis that is non-hierarchical cluster analysis k-Means with 38 countries as the data population. This analysis is done repeatedly until the obtainment number of clusters which is capable to show the differentiator power of the three characteristics and describe the high similarity within clusters. Based on the results, it turns out with 6 clusters can describe the differentiator power of characteristics of formed clusters. However, to answer the purpose of the study, only one cluster which will be taken accordance with the criteria of success for the population of countries that have similarities with Indonesia that cluster contain Indonesia therein, there are countries which is sustain crisis and non-crisis of rice in 2008, and cluster which is have the largest member among them. This criterion is met by cluster 2, which consists of 22 countries, namely Indonesia, Brazil, Costa Rica, Djibouti, Dominican Republic, Ecuador, Fiji, Guinea-Bissau, Haiti, India, Jamaica, Japan, Korea South, Madagascar, Malaysia, Mali, Nicaragua, Panama, Peru, Senegal, Sierra Leone and Suriname.

  19. Urinary paraben concentrations and in vitro fertilization outcomes among women from a fertility clinic

    Science.gov (United States)

    Mínguez-Alarcón, Lidia; Chiu, Yu-Han; Messerlian, Carmen; Williams, Paige L.; Sabatini, Mary E.; Toth, Thomas L.; Ford, Jennifer B.; Calafat, Antonia M.; Hauser, Russ

    2015-01-01

    Objective To explore the relationship between urinary paraben concentrations and IVF outcomes among women attending an academic fertility center. Design Prospective cohort study. Setting Fertility clinic in a hospital setting. Patient(s) A total of 245 women contributing 356 IVF cycles. Intervention(s) None. Quantification of urinary concentrations of parabens by isotope-dilution tandem mass spectrometry, and assessment of clinical endpoints of IVF treatments abstracted from electronic medical records at the academic fertility center. Main Outcome Measure(s) Total and mature oocyte counts, proportion of high quality embryos, fertilization rates, and rates of implantation, clinical pregnancy and live births. Results The geometric mean of the urinary concentrations of methyl (MP), propyl (PP) and butyl paraben (BP) in our study population were 133, 24 and 1.5 µg/L, respectively. In models adjusted for age, body mass index, race/ethnicity, smoking status and primary infertility diagnosis, urinary MP, PP and BP concentrations were not associated with IVF outcomes, specifically total and mature oocyte counts, proportion of high embryo quality and fertilization rates. Moreover, no significant associations were found between urinary paraben concentrations and rates of implantation, clinical pregnancy and live births. Conclusion(s) Urinary paraben concentrations were not associated with IVF outcomes among women undergoing infertility treatments. PMID:26654974

  20. Dark-matter halo mergers as a fertile environment for low-mass Population III star formation

    DEFF Research Database (Denmark)

    Bovino, S.; Latif, M. A.; Grassi, Tommaso

    2014-01-01

    While Population III (Pop III) stars are typically thought to be massive, pathways towards lower mass Pop III stars may exist when the cooling of the gas is particularly enhanced. A possible route is enhanced HD cooling during the merging of dark-matter haloes. The mergers can lead to a high ioni...... ionization degree catalysing the formation of HD molecules and may cool the gas down to the cosmic microwave background temperature. In this paper, we investigate the merging of mini-haloes with masses of a few 105 M⊙ and explore the feasibility of this scenario. We have performed three......-dimensional cosmological hydrodynamics calculations with the enzo code, solving the thermal and chemical evolution of the gas by employing the astrochemistry package krome. Our results show that the HD abundance is increased by two orders of magnitude compared to the no-merging case and the halo cools down to ∼60 K...

  1. Fertility outcomes in asthma

    DEFF Research Database (Denmark)

    Gade, Elisabeth Juul; Thomsen, Simon Francis; Lindenberg, Svend

    2016-01-01

    Evidence is increasing of an association between asthma and aspects of female reproduction. However, current knowledge is limited and furthermore relies on questionnaire studies or small populations. In a prospective observational cohort study to investigate whether time to pregnancy, the number...... of fertility treatments, and the number of successful pregnancies differ significantly between women with unexplained infertility with and without asthma.245 women with unexplained infertility (aged 23-45 years) underwent questionnaires and asthma and allergy testing while undergoing fertility treatment. 96...... women entering the study had either a former doctor's diagnosis of asthma or were diagnosed with asthma when included. After inclusion they were followed for a minimum of 12 months in fertility treatment, until they had a successful pregnancy, stopped treatment, or the observation ended.The likelihood...

  2. Dark-matter halo mergers as a fertile environment for low-mass Population III star formation

    CERN Document Server

    Bovino, S; Grassi, T; Schleicher, D R G

    2014-01-01

    While Population III stars are typically thought to be massive, pathways towards lower-mass Pop III stars may exist when the cooling of the gas is particularly enhanced. A possible route is enhanced HD cooling during the merging of dark-matter halos. The mergers can lead to a high ionization degree catalysing the formation of HD molecules and may cool the gas down to the cosmic microwave background (CMB) temperature. In this paper, we investigate the merging of mini-halos with masses of a few 10$^5$~M$_\\odot$ and explore the feasibility of this scenario. We have performed three-dimensional cosmological hydrodynamics calculations with the ENZO code, solving the thermal and chemical evolution of the gas by employing the astrochemistry package KROME. Our results show that the HD abundance is increased by two orders of magnitude compared to the no-merging case and the halo cools down to $\\sim$60 K triggering fragmentation. Based on Jeans estimates the expected stellar masses are about 10 M$_\\odot$. Our findings s...

  3. Obligatory versus elective single embryo transfer in in vitro fertilization. A population-based analysis of data from the U.K. Human Fertilisation and Embryology Authority.

    Science.gov (United States)

    Straughen, Jennifer K; Salihu, Hamisu M; Keith, Louis; Petrozzino, Jeffrey; Jones, Christopher

    2013-01-01

    To determine how obligatory single embryo transfer (SET) and elective SET influence pregnancy outcome. We compared women who underwent obligatory and elective SET using data from a comprehensive, population-based register from the United Kingdom Human Fertilisation and Embryology Authority, which contained all in vitro fertilization (IVF) treatments administered between 1991 and 1998. Generalized estimating equations were used to generate adjusted odds ratios (ORs) and 95% confidence intervals (CIs) to compare clinical pregnancy, live birth, and multiple birth rates. Obligatory and elective SET had similar clinical pregnancy and live birth rates and comparable multiple birth rates. Obligatory and elective SET were equally likely to end in a live birth (OR = 1.08; 95% CI = 0.90, 1.30). Similar results were found after restricting the data to women without previous IVF births (OR = 1.18; 95% CI = 0.98, 1.42) and without previous naturally conceived live births (OR = 1.16; 95% CI = 0.95, 1.43). This study suggests that obligatory SET can achieve pregnancy and live birth rates that are at least as good as elective SET. Equally important is the low multiple birth rate which was maintained in both forms of SET. More studies comparing elective versus obligatory SET can assist with achieving optimal pregnancy rates while preventing multiple births.

  4. Social patterns and differentials in the fertility transition in the context of HIV/AIDS: evidence from population surveillance, rural South Africa, 1993 - 2013.

    Science.gov (United States)

    Houle, Brian; Pantazis, Athena; Kabudula, Chodziwadziwa; Tollman, Stephen; Clark, Samuel J

    2016-01-01

    Literature is limited on the effects of high prevalence HIV on fertility in the absence of treatment, and the effects of the introduction of sustained access to antiretroviral therapy (ART) on fertility. We summarize fertility patterns in rural northeast South Africa over 21 years during dynamic social and epidemiological change. We use data for females aged 15-49 from the Agincourt health and socio-demographic surveillance system (1993-2013). We use discrete time event history analysis to summarize patterns in the probability of any birth. Overall fertility declined in 2001-2003, increased in 2004-2011, and then declined in 2012-2013. South Africans showed a similar pattern. Mozambicans showed a different pattern, with strong declines prior to 2003 before stalling during 2004-2007, and then continued fertility decline afterwards. There was an inverse gradient between fertility levels and household socioeconomic status. The gradient did not vary by time or nationality. The fertility transition in rural South Africa shows a pattern of decline until the height of the HIV/AIDS pandemic, with a resulting stall until further decline in the context of ART rollout. Fertility patterns are not homogenous among groups.

  5. Mouse models in male fertility research

    Institute of Scientific and Technical Information of China (English)

    Duangporn Jamsai; Moira K O'Bryan

    2011-01-01

    Limited knowledge of the genetic causes of male infertility has resulted in few treatment and targeted therapeutic options.Although the ideal approach to identify infertility causing mutations is to conduct studies in the human population,this approach has progressed slowly due to the limitations described herein.Given the complexity of male fertility,the entire process cannot be modeled in vitro.As such,animal models,in particular mouse models,provide a valuable alternative for gene identification and experimentation.Since the introduction of molecular biology and recent advances in animal model production,there has been a substantial acceleration in the identification and characterization of genes associated with many diseases,including infertility.Three major types of mouse models are commonly used in biomedical research,including knockout/knockin/gene-trapped,transgenic and chemical-induced point mutant mice.Using these mouse models,over 400 genes essential for male fertility have been revealed.It has,however,been estimated that thousands of genes are involved in the regulation of the complex process of male fertility,as many such genes remain to be characterized.The current review is by no means a comprehensive list of these mouse models,rather it contains examples of how mouse models have advanced our knowledge of post-natal germ cell development and male fertility regulation.

  6. Hospital mental health admissions in women after unsuccessful infertility treatment and in vitro fertilization: an Australian population-based cohort study.

    Directory of Open Access Journals (Sweden)

    Louise M Stewart

    Full Text Available To examine the association between in vitro fertilization (IVF and later admission to hospital with a mental health diagnosis in women who remained childless after infertility treatment.This was a population-based cohort study using linked administrative hospital and registry data. The study population included all women commencing hospital treatment for infertility in Western Australia between the years 1982 and 2002 aged 20-44 years at treatment commencement who did not have a recorded birth by the end of follow-up (15 August 2010 and did not have a hospital mental health admission prior to the first infertility admission (n=6,567. Of these, 2,623 women had IVF and 3,944 did not. We used multivariate Cox regression modeling of mental health admissions and compared women undergoing IVF treatment with women having infertility treatment but not IVF.Over an average of 17 years of follow-up, 411 women in the cohort were admitted to hospital with a mental health diagnosis; 93 who had IVF and 318 who did not. The unadjusted hazard ratio (HR for a hospital mental health admission comparing women who had IVF with those receiving other infertility treatment was 0.50 (95% confidence interval [CI] 0.40-0.63. After adjustment for age, calendar year and socio-economic status the HR was 0.56 (95% CI 0.44-0.71.IVF treatment is associated with a reduced risk of hospital mental health admissions in women after unsuccessful infertility treatment. This may be explained by the healthy cohort effect.

  7. Could Speaking for the People Often Mean Lying to the People? Populism and the Problem of Truth

    Directory of Open Access Journals (Sweden)

    Dragoş DRAGOMAN

    2014-03-01

    Full Text Available The recent developments in Romanian politics have raised a series of questions related to the special relationship between populists and the people. How could one explain that populists are no longer popular? One explanation put forward here is that politics, and especially populism, bear a moral component that affects the political system, in that populists turn democracy into what Sartori would label as “demolatry”. This means that populists keep speaking for the people, but with no real attention paid to the people, and finally, with a total despise for the real people. This changing context, with the populist leader challenging the established power system by mobilising dissatisfied citizens only to accommodate and successfully integrate the power structures previously challenged, and the subsequent moves against the real people, is exemplified for the period between 2008 and 2012, when the populists consolidated in power and were finally and ironically challenged by the people.

  8. An indirect means of assessing potential nutritional effects of dietary olestra in healthy subgroups of the general population.

    Science.gov (United States)

    Middleton, S J; Dwyer, J; Peters, J C

    1997-08-01

    The potential for olestra to affect the absorption of dietary components was measured in 18- to 44-y-old humans and the weanling pig. Results from the studies were assessed to determine if they were relevant to subgroups of the population not included in the studies. Hypothetrically, two factors that might cause the study results not to be relevant to certain subgroups are dietary pattern and metabolic need. A dietary pattern resulting in olestra-to-nutrient intake ratios greater than those tested in the studies might produce effects greater than those measured. Metabolic needs (i.e., nutrient requirements) among subgroups greater than those of the study population might mean that any effects on nutrient absorption seen in the studies would be larger among subgroups. If olestra-to-nutrient ratios and nutrient requirements of a subgroup were less than those covered in the studies, then the effects of olestra on the nutritional status of the subgroup should be no different than the effects measured in the studies. Subgroups with high olestra-to-nutrient intake ratios were identified by calculating the ratios for those nutrients assessed in the studies [i.e., macronutrients, vitamins A (including beta-carotene), D, E and K, folate, vitamin B12, calcium, iron and zinc]. Subgroups with the greatest olestra-to-nutrient intake ratios for one or more nutrients included children, teenagers and young adults, women from low income families and vegetarians. Subgroups with the greatest metabolic need for one or more nutrients included children, teenagers, and pregnant and lactating women. The olestra-to-nutrient ratios and nutrient requirements of the subgroups having the greatest ratios and requirements were compared with those of the test population. The olestra-to-nutrient intake ratios fed in the studies were greater than those for any subgroup for all nutrients except calcium, which is not affected by olestra. Metabolic needs of the test population were greater than those

  9. High coffee population density to improve fertility of an oxisol Densidade populacional de cafeeiros para melhorar a fertilidade de um latossolo

    Directory of Open Access Journals (Sweden)

    Marcos Antonio Pavan

    1999-03-01

    Full Text Available The objective of this work was to evaluate the effect of coffee (Coffea arabica L. population densities on the chemical and microbiological properties of an Oxisol. The work was carried out on soil samples of 0-20 cm depth originated from an experimental site which had been used for coffee tree spacing studies during 15 years, in Paraná State, Brazil. Eight coffee tree populations were evaluated: 7143, 3571, 2381, 1786, 1429, 1190, 1020, and 893 trees/ha. Increasing plant population increased soil pH, exchangeable Ca, Mg, K, extractable P, organic carbon, moisture content and coffee root colonization by vesicular arbuscular mycorrhizal fungi, and decreased exchangeable Al and microbial biomass. Such results were attributed to better erosion control, improved plant residue management and nutrient cycling, and decreased leaching losses. Increasing coffee tree population per unit of area has shown to be an important reclamation recuperation strategy for improving fertility of the acid soils in Paraná, Brazil.O objetivo deste trabalho foi verificar os efeitos de diferentes densidades de população de cafeeiros (Coffea arabica L. nas propriedades químicas, físicas e microbiológicas do solo. Amostras de um Latossolo foram coletadas na profundidade 0-20 cm em um experimento de campo onde estavam sendo avaliadas diferentes populações de cafeeiros. Os tratamentos foram 7.143, 3.571, 2.381, 1.786, 1.429, 1.190, 1.020 e 893 covas/ha. Os resultados demonstraram que o aumento da população de plantas por unidade de área aumentou o pH, o Ca, o Mg e o K trocáveis, o P disponível, o carbono orgânico, o teor de umidade e a colonização radicular por micorrizas, e diminuiu o Al trocável e a biomassa microbiana. Foram considerados como causas da melhoria da fertilidade do solo, sob cafeeiros adensados, o adequado controle da erosão, o correto manejo dos resíduos vegetais e a baixa lixiviação dos íons. O manejo da população de cafeeiros pode

  10. Mean Field Analysis of Large-Scale Interacting Populations of Stochastic Conductance-Based Spiking Neurons Using the Klimontovich Method

    Science.gov (United States)

    Gandolfo, Daniel; Rodriguez, Roger; Tuckwell, Henry C.

    2017-01-01

    We investigate the dynamics of large-scale interacting neural populations, composed of conductance based, spiking model neurons with modifiable synaptic connection strengths, which are possibly also subjected to external noisy currents. The network dynamics is controlled by a set of neural population probability distributions (PPD) which are constructed along the same lines as in the Klimontovich approach to the kinetic theory of plasmas. An exact non-closed, nonlinear, system of integro-partial differential equations is derived for the PPDs. As is customary, a closing procedure leads to a mean field limit. The equations we have obtained are of the same type as those which have been recently derived using rigorous techniques of probability theory. The numerical solutions of these so called McKean-Vlasov-Fokker-Planck equations, which are only valid in the limit of infinite size networks, actually shows that the statistical measures as obtained from PPDs are in good agreement with those obtained through direct integration of the stochastic dynamical system for large but finite size networks. Although numerical solutions have been obtained for networks of Fitzhugh-Nagumo model neurons, which are often used to approximate Hodgkin-Huxley model neurons, the theory can be readily applied to networks of general conductance-based model neurons of arbitrary dimension.

  11. Mean Field Analysis of Large-Scale Interacting Populations of Stochastic Conductance-Based Spiking Neurons Using the Klimontovich Method

    Science.gov (United States)

    Gandolfo, Daniel; Rodriguez, Roger; Tuckwell, Henry C.

    2017-03-01

    We investigate the dynamics of large-scale interacting neural populations, composed of conductance based, spiking model neurons with modifiable synaptic connection strengths, which are possibly also subjected to external noisy currents. The network dynamics is controlled by a set of neural population probability distributions (PPD) which are constructed along the same lines as in the Klimontovich approach to the kinetic theory of plasmas. An exact non-closed, nonlinear, system of integro-partial differential equations is derived for the PPDs. As is customary, a closing procedure leads to a mean field limit. The equations we have obtained are of the same type as those which have been recently derived using rigorous techniques of probability theory. The numerical solutions of these so called McKean-Vlasov-Fokker-Planck equations, which are only valid in the limit of infinite size networks, actually shows that the statistical measures as obtained from PPDs are in good agreement with those obtained through direct integration of the stochastic dynamical system for large but finite size networks. Although numerical solutions have been obtained for networks of Fitzhugh-Nagumo model neurons, which are often used to approximate Hodgkin-Huxley model neurons, the theory can be readily applied to networks of general conductance-based model neurons of arbitrary dimension.

  12. Fertility incentives and disincentives.

    Science.gov (United States)

    Financioglu, N

    1984-06-01

    Some 40 countries use some form of incentives and disincentives in support of population policies, about half with the aim of reducing fertility and half with the aim of increasing it. These schemes range from limitations on tax and family allowances or maternity benefits after a given family size has been reached to payments to acceptors of fertility control methods. Some schemes aim to eliminate or reduce the cost and inconvenience people may face in achieving their fertility preferences, whereas others contain an element of deterrence. It is difficult to isolate and measure the impact of incentives on fertility from the effects of other factors such as family planning service availability or modernization. Studies in pronatalist countries suggest that incentive schemes produce short-term fertility increases without a change in average family size. Monetary incentives must be constantly increased to keep pace with inflation, placing a heavy burden on government budgets. Administrative capacity to operate the scheme is critical in terms of both manpower and efficient systems for record keeping, monitoring, and close supervision to prevent abuse. There is also considerable debate on the moral and ethical implications of incentives and disincentives as policy tools. Incentives offered for the acceptance of a particular fertility control method potentially contravene the principle of voluntary and informed consent. In addition, the relative value of the reward is greater for those in the lower income groups. The discriminatory nature of certain types of incentives and disincentives is illustrated by measures introduced in Singapore that give highest priority in school enrollment to the children of highly educated mothers with 2-3 children. This ruling is expected to further intensify the controversy surrounding incentive and disincentive schemes.

  13. Endogenous Fertility in Models of Growth Endogenous Fertility in Models of Growth

    Directory of Open Access Journals (Sweden)

    Allan Drazen

    1993-03-01

    Full Text Available Endogenous Fertility in Models of Growth Most theories of economic growth ignore determinants of growth in population. The common assumption of constant population growth is strikingly inconsistent with the data, which reveal a logistic pattern of population growth, the acceleration often coinciding with industrialization. After surveying existing theories of endogenous population, we propose a model in which the family replaces the market in a "traditional" sector. Children are both the primary source of labor and the sole means of saving in this sector, with output divided behween generations via bargaining. Industrialization improves the oportunities of children outside the rural sector. It thus leads not only to higher outmigration, but also, by increasing children's bargaining power and hence their share of output, lowers the incentive to bear children. The model can thus explain observed changes in both overall population growth and in its sectorai composition.

  14. Women's education and fertility behaviour.

    Science.gov (United States)

    1993-12-01

    The education of women results in changes in women's health status, family well being, and fertility decline. The aim of human rights and social justice is also served by increasing women's educational levels. A review of the trends in developing countries has shown that there is a strong correlation between advanced female education (10 or more years) and lower fertility. Data for 26 countries was presented in table form for total fertility rates by years of education. There were many differences in the patterns of fertility by educational level based on country level of development. The data appeared to show stronger correlations between fertility and education in more prosperous societies; culture and social structure also influenced fertility. Partial primary education has been shown in some countries to be related to increased fertility. A UN study found a curvilinear relationship between fertility and education in 14 out of 38 countries with World Fertility Surveys. There were only 3 countries with Demographic and Health Surveys which showed the curvilinear pattern. The UN study confirmed that maternal education was related to shorter durations of postpartum abstinence and short durations of lactation. Caution was urged in interpreting that an increase in a few years of schooling in a dominant rural, illiterate population would facilitate rapid fertility decline. A critical threshold effect for educational attainment was found in mainly the least developed countries. Female education has direct and indirect effects on fertility. Education may affect breast feeding patterns, contraceptive use, social norms about small families, later age at marriage, and later age at first birth. The suggestion was that education provided for reproductive choice and reduces the gap between actual and desired family size. At the country and individual level of analysis, contraceptive use was linked with education. Effective contraceptive use was still however impeded by

  15. Fertility, Migration, and Altruism

    OpenAIRE

    2000-01-01

    Consider migration to a higher income region as a human capital investment in which parents bear migration costs and children share returns. Migrants from a population with heterogeneous intergenerational discount rates will be self-selected on intergenerational altruism. Thus, immigrants may be self-selected on fertility. Soviet Jews who migrate to Israel despite high migration costs have significantly more children than members of the same birth cohort who migrate later when costs are low. ...

  16. Modeling Strategic Interventions in a Population With a Total Fertility Rate of 8.3: A Cross-Sectional Study of Idjwi Island, DRC - With Appendix Detailing Patterns of Poverty and Disease Among the Bany'Idjwi People

    OpenAIRE

    Hadley, Michael B

    2015-01-01

    Idjwi Island, DRC, has a total fertility rate of 8.3, one of the highest in the world. Rapid population growth has led to widespread environmental degradation and food insecurity. Meanwhile family planning services are largely unavailable. We conducted a representative survey of 2,078 households measuring standard reproductive health indicators. We also interviewed local women, community leaders, and clinicians about access to reproductive services. In the survey, over half of all women repor...

  17. 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)

  18. 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)

  19. Habitat use of a population of bottlenose dolphins, Tursiops truncatus gephyreus, analyzed by means of Kernel Density Estimation (KDE) method

    OpenAIRE

    Cransveld, Alice; Denoël, Mathieu; Das, Krishna; Vermeulen, Els

    2014-01-01

    The San Antonio Bay (SAB), in Patagonia, Argentina, harbors a resident population of bottlenose dolphins (Tursiops truncatus gephyreus). It seems a privileged area to give birth and nurse calves. In the context of declining populations worldwide and more particularly in South America, preserving the SAB population takes a considerable significance. Yet the SAB is facing human population growth and touristic development, which represent potential threats for the dolphin population, especially ...

  20. Fertility and the economy.

    Science.gov (United States)

    Becker, G S

    1992-08-01

    Fertility and the economy is examined in the context of the Malthusian question about the links between family choices and longterm economic growth. Micro level differences are not included not are a comprehensive range of economic or determinant variables. Specific attention is paid to income and price effects, the quality of children, overlapping generations, mortality effects, uncertainty, and economic growth. Fertility and the demand for children in linked to parental incomes and the cost of rearing children, which is affected by public policies that change the costs. Demand is also related to child and adult mortality, and uncertainty about sex of the child. Fertility in one generation affects fertility in the next. Malthusian and neoclassical models do not capture the current model of modern economies with rising income/capita and human and physical capital, extensive involvement of married women in the labor force, and declining fertility to very low levels. In spite of the present advances in firm knowledge about the relationships between fertility and economic and social variables, there is still much greater ignorance of the interactions. The Malthusian utility function that says fertility rises and falls with income did hold up to 2 centuries of scrutiny, and the Malthusian inclusion of the shifting tastes in his analysis could be translated in the modern context to include price of children. The inclusion of net cost has significant consequences, i.e., rural fertility can be higher because the cost of rearing when children contribute work to maintaining the farm is lower than in the city. An income tax deduction for children in the US reduces cost. Economic growth raises the cost of children due the time spent on child care becoming more valuable. The modern context has changed from Malthusian time, and the cost of education, training, and medical care is relevant. The implication is that a rise in income could reduce the demand for children when

  1. Sexuality and fertility in men with hypospadias; improved outcome.

    Science.gov (United States)

    Örtqvist, L; Fossum, M; Andersson, M; Nordenström, A; Frisén, L; Holmdahl, G; Nordenskjöld, A

    2016-12-19

    The aim of this study was to investigate sexual function and fertility in adult men born with hypospadias. Patients born with hypospadias, age-matched controls, and a group of circumcised men completed a questionnaire constructed to reflect their psychosexual situation and fertility. Core gender identity, sexual orientation, and gender role behavior was also assessed. 167 patients [63% distal, 24% mid shaft and 13% proximal, mean age 34 (19-54) years], 169 controls from the general population [mean age 33 (19-48) years] and 47 controls circumcised because of phimosis (mean age 26 [19-44]) participated and completed the questionnaire. There were no differences in having a partner, reported fertility, age at sexarche (mean age 17.8), number of sex partners or sexual interest between the patients and controls. More patients than controls reported anejaculation. Reported glanular sensitivity was lower in hypospadias patients and circumcised controls compared with non-circumcised controls. The odds of being satisfied with their sexual life increased with a higher penile perception score in patients (OR = 1.54, p = 0.01). There was no association with penile length. Sexual orientation, core gender identity and gender role behavior were sex-typical in both patients and controls. Patients with proximal hypospadias had a lower reported fertility, experienced anejaculation more often, and were less satisfied with their sexual life. Men born with hypospadias have a good long-term outcome concerning sexual function and fertility. Men born with proximal hypospadias have a more impaired outcome concerning both sexual function and fertility. As satisfaction with genital appearance is important for sexual life satisfaction, clinical, and psychological follow-up into adulthood is especially important in boys born with proximal hypospadias.

  2. 施氮肥对荒漠草原土壤微生物种群及微生物量的影响%Effects of Nitrogen Fertilization on Desert Grassland Soil Microbial Population and Microbial Biomass

    Institute of Scientific and Technical Information of China (English)

    郭永盛; 李俊华; 李鲁华; 危常州; 褚贵新; 王飞; 董鹏

    2011-01-01

    [Objective] The aim of the article was set to analyze the effects of nitrogen fertilization on soil microbial population and microbial biomass in desert grassland to know their response to nitrogen fertilizer and to clarify the indication effects of microorganism on environmental qualtiy change . [ Method ] The dilution plate count chloroform and fumigation - K2SO4 extraction of nitrogen were used to study the effect of nitrogen fertilization on three different environments: the microbial population and desert grassland microbial biomass carbon, microbial biomass N ( Bc, BN) . [ Result]Soil bacteria is the main specie in the soil, followed by actinomycetes and fungi is the least ; N fertilizer can significantly increase all three populations of soil rmcrobial, the ratio was increased by 13 . 5% - 427 . 6% , 7. 8% - 88. 2% and 16. 7% - 180. 6 % , respectively; N fertilizer can significantly increas microbial biomass carbon, nitrogen, the ratio was 29 .8% - 110.8% and 51.2% - 161.7% , respectively , effect of N fercilization on soil microbial populations and microbial biomass of the extent of precipitation and fertilization in the environment is related to the precipitation,the greater precipitation, the more obvious influence, the effect of fertilization is less obvious with the deepening of the soil. [ Conclusion] Nitrogen changes in soil microbial populations and SMBc, SMBN, different fertilization environment can also lead to the difference of soil microbial populations and SMBc, SMBN .%[目的]通过分析施氮肥对土壤微生物种群及微生物量,认识荒漠草原土壤微生物种群及微生物量对氮肥的响应,明确微生物对环境质量变化的指示作用.[方法]应用稀释平板计数法和氯仿熏蒸-K2SO4提取法分别研究施氮肥对三种不同环境的荒漠草原土壤微生物种群及微生物量碳、微生物量氮(Bc,BN)之间的影响.[结果]在土壤中细菌为土壤微生物的主要种群,其次

  3. Fertility in the mothers of firstborn homosexual and heterosexual men.

    Science.gov (United States)

    Blanchard, Ray

    2012-06-01

    This study tested the balancing selection hypothesis, that is, genes predisposing men to homosexuality escape elimination from the population because the decreased fertility of men with the heritable form of homosexuality is offset by an increased fertility among biological relatives who carry the same genetic variants. The index subjects (probands) were 40,197 firstborn heterosexual men and 4,784 firstborn homosexual men retrieved from six archival data sets, all of which had previously been used in published research. The measure of familial (specifically, parental) fertility was the proband's number of younger siblings. The results directly contradicted the prediction of the balancing selection hypothesis. In four of the six samples, the homosexual probands had significantly fewer younger siblings; in the other two samples, the means were not significantly different. It is possible that mothers who produce a homosexual son at their first delivery include a biologically distinct subpopulation of mothers of homosexual sons.

  4. How to influence fertility: the experience so far.

    Science.gov (United States)

    Weeks, J R

    1990-09-01

    Even though fertility in the US is 2, the population grows each year by 2.5 million people due to natural increase and immigration. The US has never had a formal population policy to influence its birth rate. Yet the US government advises other nations, especially developing nations, how they should go about reducing their fertility. Instead the US can learn from population policies of direct disincentives, such as no income tax allowance for 3 children. In Indonesia, the president and Islamic religious leaders strongly support family planning. In Mexico, both the public and private sectors provide family planning services. The US does not have experience in influencing fertility declines, since fertility declined due to economic development over a period of time. Some scholars claim that there are 3 preconditions for a sustained decline in fertility, all of which have significance for setting population policies. The 1st is called rational choice in which conditions are such in a society that women can make their own decision. For example, the existence of legislation that guarantees women the right to act in their own interest, including the right to make their own reproductive decisions. The 2nd involves policies or conditions that motivate individuals and/or couples to limit family size. Incentives and disincentives can provide the needed motivation. For example, the government pays a woman for not having a child for a specific interval. The last precondition includes the necessity of having means available to limit family size. These means include knowledge of contraceptive methods and accessibility to them.

  5. Migrant fertility differentials in Ecuador.

    Science.gov (United States)

    Rundquist, F; Brown, L A

    1989-01-01

    The effects of migration on fertility in Ecuador were analyzed by subdividing migrant categories into permanent-, return-, circular-, and non-migrants, and context factors into 6 socioeconomic and agrarian variables. The study is introduced with a conceptual framework that explains personal intermediate variables and their influence on fertility in terms of demographic transition theory, and then defines the influences of selection for fertility, disruption of marital unions, and socialization into fertility norms at the origin vs. assimilation of norms at the destination. Migrants are usually better educated, younger and upwardly mobile, all selecting for lower fertility. Migration disrupts formation of marital unions, and causes separation of spouses, lowering fertility. Data for this study were from the 1974 and 1982 Ecuadorian Population Censuses. The contextual variables analyzed were urban/rural; manufacturing/agricultural; mineral extraction/economic recession; long/recent agricultural settlement; domestic/export crop; and large/medium sized farm. The analysis of personal attributes showed that fertility increased over the range on non-migrants through circular-, return- to permanent-migrants, a finding explained by degrees of disruption of unions. Higher fertility was associated with less education, lower economic participation, higher prevalence of marriage, longer residence and older ages. Regression analysis also showed that personal attributes outweighed contextual factors: thus age, marriage rates, residence time, education and economic activity were significant. Contextual factors were important only for non-migrants, except for destination variables which affected return-migrants and origin variables which affected circular-migrants. Low fertility was associated with urbanization, industrialization, mineral extraction, large farms, recent farm settlement and export crops. The results indicate cear influences of modernity and place influences on

  6. The fertility of internal migrants to Kinshasa.

    Science.gov (United States)

    Anglewicz, Philip; Corker, Jamaica; Kayembe, Patrick

    2017-01-01

    The rapid population growth of many African cities has important implications for population health, yet little is known about factors contributing to increasing population, such as the fertility of internal migrants. We examine whether in-migrants to Kinshasa have different fertility patterns than lifetime Kinshasa residents, and identify characteristics of migrants that may explain differences in fertility. We also use detailed migration histories to examine whether fertility differs by features of migration. We use representative data from the PMA2020 Project for 2197 women in Kinshasa, including 340 women who moved to Kinshasa. We examine differences between migrants and non-migrants in fertility and other fertility-related characteristics. We also examine whether fertility differs by duration of residence in Kinshasa, number of lifetime moves, age at first migration, urban/rural classification of birthplace, and the distinction between intra-Kinshasa migration and migration to Kinshasa.. Migrants have significantly higher fertility than permanent Kinshasa residents, but the difference is relatively small in magnitude. This higher fertility appears due in part to patterns of contraceptive use among migrants. There is noteworthy heterogeneity among migrants: higher fertility among migrants is associated with longer duration in Kinshasa, more lifetime moves, urban-Kinshasa migration, older age at first migration, and moving to Kinshasa from outside (as opposed to intra-Kinshasa migration).

  7. Demographic and fertility characteristics of 4 squatter settlements.

    Science.gov (United States)

    Yusof, K; Zulkifli, S N

    1985-01-01

    The demographic and fertility profiles of 4 squatter areas, 2 with Sang Kancil, a community development project designed specifically for squatter settlements in Kuala Lumpur, are described. Data were taken from a census conducted in 1982. Figure 1 maps out the location of the study areas in the Federal Territory. The squatter household (5.4 members) varied little from the average Malaysian household. The average age of the male head of household was 40 years, i.e., not within the high fertility group; the mean duration of stay was 10 years. Household income/month averaged M$760, falling between estimates for urban and rural mean. Comparing the data on the 2 squatter areas, the non-Sang Kancil head of household was, on average, slightly older and had stayed about 2 years longer than his Sang Kancil counterpart. These differences were statistically significant. Both areas were comparable with regard to household income and size. Ethnically, the Sang Kancil areas were predominantly Malay, comprising 86% of total households. The control areas had a more mixed ethnic structure. From 1978-81, annual increases in total population had been fairly uniform, at around 2%, in non-Sang Kancil Areas. Yet, the Sang Kancil population experienced a growth spurt in 1980, which subsequently declined and appeared to level off. 1982 figures were disregarded in this analysis as they were based on a 1/2 year enumeration only. The age distribution pattern of all squatter areas combined was fairly similar to the national distribution pyramid but for a higher proportion of people in the 15-44 age group than national figures. The proportion of dependents, 0-14 years, was comparable despite having more people in this fertile age group. The proportion of infants (0-11 months) in the control population was constant, but there was a decline down to control values by the end of the surveyed period in the Sang Kancil group. In the toddler group, decreases were evident for both populations

  8. Stochastic multi-scale models of competition within heterogeneous cellular populations: simulation methods and mean-field analysis

    CERN Document Server

    de la Cruz, Roberto; Spill, Fabian; Alarcón, Tomás

    2016-01-01

    We propose a modelling framework to analyse the stochastic behaviour of heterogeneous, multi-scale cellular populations. We illustrate our methodology with a particular example in which we study a population with an oxygen-regulated proliferation rate. Our formulation is based on an age-dependent stochastic process. Cells within the population are characterised by their age. The age-dependent (oxygen-regulated) birth rate is given by a stochastic model of oxygen-dependent cell cycle progression. We then formulate an age-dependent birth-and-death process, which dictates the time evolution of the cell population. The population is under a feedback loop which controls its steady state size: cells consume oxygen which in turns fuels cell proliferation. We show that our stochastic model of cell cycle progression allows for heterogeneity within the cell population induced by stochastic effects. Such heterogeneous behaviour is reflected in variations in the proliferation rate. Within this set-up, we have established...

  9. Mean values of Steiner, Tweed, Ricketts and McNamara analysis in Maratha ethnic population: A cephalometric study

    OpenAIRE

    Manan Bharat Atit; Sonali Vijay Deshmukh; Jayesh Rahalkar; Vijay Subramanian; Charudatt Naik; Milind Darda

    2013-01-01

    Objectives: Cephalometric norms derived for Caucasian population are routinely used for investigations. As these norms show a great degree of variation when applied to different populations, it becomes necessary to establish the norms for every ethnic group. The present study was designed to derive norms for the Maratha ethnic population, which would be comparable in diagnosis and treatment planning, to the Steiner, Tweed, Ricketts and McNamara cephalometric analysis. Materials and Methods: T...

  10. Semen quality in sub-fertile range for a significant proportion of young men from the general German population: a co-ordinated, controlled study of 791 men from Hamburg and Leipzig.

    Science.gov (United States)

    Paasch, Uwe; Salzbrunn, Andrea; Glander, Hans Juergen; Plambeck, Kai; Salzbrunn, Harald; Grunewald, Sonja; Stucke, Julia; Vierula, Matti; Skakkebaek, Niels E; Jørgensen, Niels

    2008-04-01

    Population studies have shown that a high proportion of Nordic men may have so poor semen quality that they can be classified as sub-fertile according to international standards. A question is whether the Nordic data are specific for the Nordic countries or they should be seen as an expression of a general trend in Europe. We therefore carried out a prospective study of semen quality of young men raised in the former East Germany (Leipzig) and West Germany (Hamburg). To enable inter-regional comparisons, we utilized a common European research protocol previously used in studies in the Nordic-Baltic region. Three hundred and thirty-four young men representative of the general population from Hamburg, and 457 from Leipzig delivered semen samples, underwent physical examinations and provided information on life-style and reproductive health parameters. The study period in Hamburg was February 2003--July 2004, and in Leipzig July 2003--April 2005. No significant differences were observed in sperm concentration (median 46, 42, and 44 million/mL for men from Hamburg, Leipzig and the combined Hamburg-Leipzig group respectively) or total sperm count (154,141 and 149 million), whereas the differences for morphologically normal spermatozoa (9.4 and 8.4%) and motile spermatozoa (67 and 81%) were significantly different. Previously published studies have shown reduced fertility with decreasing sperm concentrations below 40-55 millions/mL and normal sperm morphology below 9-19%. Thus, a large fraction of young German men seem to have impaired semen quality that may reduce their natural fertility. However, it remains to be investigated to what extent poor semen quality contributes to the low German fertility rates.

  11. Does Female Schooling Reduce Fertility? Evidence from Nigeria. NBER Working Paper No. 13070

    Science.gov (United States)

    Osili, Una Okonkwo; Long, Bridget Terry

    2007-01-01

    The literature generally points to a negative relationship between female education and fertility. Citing this pattern, policymakers have advocated educating girls and young women as a means to reduce population growth and foster sustained economic and social welfare in developing countries. This paper tests whether the relationship between…

  12. The Potential Impact of Changes in Fertility on Infant, Child, and Maternal Mortality. World Bank Staff Working Papers No. 698 and Population and Development Series No. 23.

    Science.gov (United States)

    Trussell, James; Pebley, Anne R.

    The relationship between changes in the timing and quantity of fertility, such as those that might result from an effective family planning program in developing countries, and changes in child and maternal mortality is examined. Results from five multivariate studies estimate the changes in mortality that might occur from altering maternal age,…

  13. Infertility Treatment and Fertility-Specific Distress: A Longitudinal Analysis of a Population-Based Sample of U.S. Women

    Science.gov (United States)

    Greil, Arthur L.; McQuillan, Julia; Lowry, Michele; Shreffler, Karina M.

    2011-01-01

    Because research on infertile women usually uses clinic-based samples of treatment seekers, it is difficult to sort out to what extent distress is the result of the condition of infertility itself and to what extent it is a consequence of the experience of infertility treatment. We use the National Survey of Fertility Barriers, a two-wave national probability sample of U.S. women, to disentangle the effects of infertility and infertility treatment on fertility-specific distress. Using a series of ANOVAs, we examine 266 infertile women who experienced infertility both at Wave 1 and at Wave 2, three years later. We compare eight groups of infertile women based on whether or not they have received treatment and on whether or not they have had a live birth. At Wave 1, infertile women who did not receive treatment and who had no live birth reported lower distress levels than women who received treatment at Wave 1 only, regardless of whether their infertility episode was followed by a live birth. At Wave 2, women who received no treatment have significantly lower fertility-specific distress than women who were treated at Wave 1 or at Waves 1 and 2, regardless of whether there was a subsequent live birth. Furthermore, fertility-specific distress did not increase over time among infertile women who did not receive treatment. The increase in fertility-specific distress was significantly higher for women who received treatment at Wave 2 that was not followed by a live birth than for women who received no treatment or for women who received treatment at Wave 1 only. These patterns suggest that infertility treatment is associated with levels of distress over and above those associated with the state of being infertile in and of itself. PMID:21645954

  14. Mean values of Steiner, Tweed, Ricketts and McNamara analysis in Maratha ethnic population: A cephalometric study

    Directory of Open Access Journals (Sweden)

    Manan Bharat Atit

    2013-01-01

    Full Text Available Objectives: Cephalometric norms derived for Caucasian population are routinely used for investigations. As these norms show a great degree of variation when applied to different populations, it becomes necessary to establish the norms for every ethnic group. The present study was designed to derive norms for the Maratha ethnic population, which would be comparable in diagnosis and treatment planning, to the Steiner, Tweed, Ricketts and McNamara cephalometric analysis. Materials and Methods: The sample consisted of 60 adult subjects (30 males and 30 females of Maratha ethnic origin. The age ranged between 18 and 26 years. The cephalograms of the subjects were subjected to Steiner, Tweed, Ricketts and McNamara cephalometric analysis and were complemented by a few additional readings. Result: The cephalometric norms for Steiner, Tweed, Ricketts and McNamara cephalometric analysis of the Maratha population differed significantly from the Caucasian population. Comparison of our sample with the other ethnic group reaffirmed the need to develop separate standards for different populations. Conclusion: Therefore, it is legitimate and important for those undertaking orthodontic treatment for patients of Maratha ethnicity to use cephalometric norms for Maratha ethnic population.

  15. A Research on the Second Childbirth Expectation and the Birth Plan for the Fertility Age Population of Chinese%中国育龄人群二孩生育意愿与生育计划研究

    Institute of Scientific and Technical Information of China (English)

    张丽萍; 王广州

    2015-01-01

    首先提出构建队列终身二孩生育意愿方法,并以2012-2014年中国家庭幸福感热点问题调查数据为基础,对我国育龄人群生育意愿与生育计划进行测量。研究发现,育龄人群意愿生育水平较低且保持稳定,全部育龄人群的二孩终身生育意愿稳定在55%左右,而单独的生育意愿更低,明确打算生育二孩的单独育龄夫妇不到30%,而明确不打算生育二孩的单独育龄妇女超过40%。根据目前的调查结果,考虑到三孩及以上意愿生育人群比例的下降,取消生育限制与实行全面二孩政策的差别不大。即使二孩生育意愿与生育计划之间不存在差距,以往把理想子女数和有偏差的二孩生育意愿作为实际的生育水平来进行判断也是有误的。%Based on the construction of the cohort second childbirth expectation and taking the 2012, 2013 and 2014 data of Happiness of Chinese Family as example, this paper has measured the second childbirth expectation and the birth plan of the fertility age population of Chinese. We found the fertility age population of Chinese has relative low and stable second childbirth expectation. It is about 55% of the fertility age population expected to have the second child. Comparing with the all fertility age population, the couples with one spouse being an only child has much lower fertility expectation. Only 30% of the couples with one spouse being an only child have the clearly expectation to have the second child and more than 40% of them do not want the second child. Considering on the probability of the third child and above is very low, the differences between no family planning policy and the second child policy are not very big. Even if there is no difference between the second birth expectation and the real birth plan, it will make wrong conclusion for some researches taking the ideal number of children or fertility expectation as fertility plan.

  16. Effects of elevated mean and extremely high temperatures on the physio-ecological characteristics of geographically distinctive populations of Cunninghamia lanceolata

    Science.gov (United States)

    Zhou, Ting; Jia, Xiaorong; Liao, Huixuan; Peng, Shijia; Peng, Shaolin

    2016-12-01

    Conventional models for predicting species distribution under global warming scenarios often treat one species as a homogeneous whole. In the present study, we selected Cunninghamia lanceolata (C. lanceolata), a widely distributed species in China, to investigate the physio-ecological responses of five populations under different temperature regimes. The results demonstrate that increased mean temperatures induce increased growth performance among northern populations, which exhibited the greatest germination capacity and largest increase in the overlap between the growth curve and the monthly average temperature. However,tolerance of the southern population to extremely high temperatures was stronger than among the population from the northern region,shown by the best growth and the most stable photosynthetic system of the southern population under extremely high temperature. This result indicates that the growth advantage among northern populations due to increased mean temperatures may be weakened by lower tolerance to extremely high temperatures. This finding is antithetical to the predicted results. The theoretical coupling model constructed here illustrates that the difference in growth between populations at high and low latitudes and altitudes under global warming will decrease because of the frequent occurrence of extremely high temperatures.

  17. Comparação das comunidades de Sminthuroidea e Onychiuridae (Collembola entre plantio direto em três níveis de fertilidade, plantio convencional e um ecossistema natural (campo nativo em Ponta Grossa, Paraná, Brasil Coniparison of the communities of Sminthuroidea and Onychiuridae (Collembola among no-tillage in three levels of fertility, conventional tillage and a natural ecosystem (native grassland in Ponta Grossa, Paraná, Brazil

    Directory of Open Access Journals (Sweden)

    Klaus Dieter Sautter

    1999-03-01

    Full Text Available This work had as objective to compare the communities of Sminthuroidea and Onychiuridae (Collembola among no-tillage in three fertility levels, conventional tillage and a natural ecosystem (native grassland. In the conventional tillage and in the no-tillage in area of medium fertility, the community of Sminthuroidea had regular fluctuation along the period of the experiment, but wtth low densities. The no-tillage in area of high fertility presented a populational pick in the autumn; the no-tillage in area of low fertility, in the spring; and, the natural ecosystem, in the summer. As the final mean density of the population of Sminthuroidea, was observed that the no-tillage in area of low fertility went numerically superior to the others, proceeded by the natural ecosystem, no-tillage in area of high fertility, conventional tillage, and, finally, no-tillage in area of medium fertility. Onychiuridae had three populational picks in the no-tillage in area of low fertility: being a larger in the winter and other two, smaller in the summer and in the autumn. In the no-tillage in area of medium fertility presented only a populational pick in the winter. In the other treatments there was not significantly populational picks. In relation to the final mean density ofthe community of Onychiuridae, the no-tillage plantation in area of low fertility was superior, proceeded by the other treatments of no-tillage, and, in third plan, the natural ecosystem and the conventional tillage.

  18. The functional transfer of genes from the mitochondria to the nucleus: the effects of selection, mutation, population size and rate of self-fertilization.

    Science.gov (United States)

    Brandvain, Yaniv; Wade, Michael J

    2009-08-01

    The transfer of mitochondrial genes to the nucleus is a recurrent and consistent feature of eukaryotic genome evolution. Although many theories have been proposed to explain such transfers, little relevant data exist. The observation that clonal and self-fertilizing plants transfer more mitochondrial genes to their nuclei than do outcrossing plants contradicts predictions of major theories based on nuclear recombination and leaves a gap in our conceptual understanding how the observed pattern of gene transfer could arise. Here, with a series of deterministic and stochastic simulations, we show how epistatic selection and relative mutation rates of mitochondrial and nuclear genes influence mitochondrial-to-nuclear gene transfer. Specifically, we show that when there is a benefit to having a mitochondrial gene present in the nucleus, but absent in the mitochondria, self-fertilization dramatically increases both the rate and the probability of gene transfer. However, absent such a benefit, when mitochondrial mutation rates exceed those of the nucleus, self-fertilization decreases the rate and probability of transfer. This latter effect, however, is much weaker than the former. Our results are relevant to understanding the probabilities of fixation when loci in different genomes interact.

  19. [The impact of obesity on fertility].

    Science.gov (United States)

    Pesant, M-H; Wunder, D; Pralong, F; Giusti, V

    2010-03-31

    There are many negative impacts of obesity on fertility. Obese couples present decreased sperm count, decreased ovulation and conception rates, increased erectile dysfunction and spontaneous abortion rate as well as increased maternal and foetal complications of pregnancy. Moreover, obesity tends to decrease response to fertility treatments. Fortunately, intensive lifestyle modifications can restore fertility while decreasing pregnancy complications risk. With the increasing trend of obesity to affect young populations, taking care of these infertile couples rapidly is capital to restore fertility and decrease its related pregnancy complications.

  20. Investigation of the stability of hemiclonal population systems of water frogs hybridogeneous complex by the means of simulation modeling

    Directory of Open Access Journals (Sweden)

    M. O. Kravchenko

    2011-01-01

    Full Text Available The concept of stability used in ecology and mathematics is analyzed. Stability is interpreted as the ability of the system to remain in a restricted zone of a phase space that corresponds to a certain type of systems. This approach is applied to describe changes in the structure of hemiclonal population systems of hybridogenous complex of water frogs (Pelophylax esculentus complex. Simulation model of these population systems built on a recursive difference equations in MS Excel is used. The dynamics of transitions in the part of phase space of the hemiclonal populationsystems of water frogs is described. Typology of stabile states of biosystems is analyzed.

  1. An application of a probabilistic fertility model to estimate some female family life cycle stages in Paraguay.

    Science.gov (United States)

    Neupert, R F

    1994-01-01

    Women's life cycle involves reproduction, labor force, and inactivity. In developing countries with inadequate data, mathematical models can be used to analyze economic behavior of individuals and families in different stages of the life cycle. This study described a model and empirically tested the model on data from Paraguay. The model provided estimates of the mean age of women at first birth, the mean age of women at last birth, time spent in reproduction, and mean life after the birth of the last child for 1950-55, 1980-85, and projection to 2020-25. Values were generated from age-specific mortality and fertility rates. Simulations were performed with varying mortality and fertility schedules. The method was based on techniques developed by Krishnamoorty, who based his methods on models proposed by Hoem and Goodman, Keyfitz, and Pullum. The method was based on an assumption of a stable population with a fixed age pattern of mortality and fertility. An assumption was also that more and less fertile women had the same mortality risks, and fertility and mortality at any one age was applicable to all ages. The total and net fertility rates and life expectancy followed a linear pattern. Application of the method showed that the net fertility rate declined by 27% from 6.15 during 1950-55 to 4.49 during 1980-85, but the time spent in reproduction declined only by 15%, from 15.7 years to 15.9 years. The cause of fertility decline was not a shortened reproductive period, but birth spacing. Projections to 2020-25 showed a decline in the reproductive period of 7 years and a net fertility rate of 3.0 children per woman. When a simulation of one of the 8 UN models of fertility age structure was used to project future fertility, the results showed the reproductive period declined from 11.8 years to 9.7 years. When fertility was assumed to be 2.3, which was considerably lower than 4.49 during 1980-85, the results showed replacement level fertility during 2020-25 and an early

  2. Socioeconomic status and fertility decline

    DEFF Research Database (Denmark)

    Dribe, Martin; Breschi, Marco; Gagnon, Alain

    2017-01-01

    The timings of historical fertility transitions in different regions are well understood by demographers, but much less is known regarding their specific features and causes. In the study reported in this paper, we used longitudinal micro-level data for five local populations in Europe and North ...

  3. Genotype × Cohort Interaction on Completed Fertility and Age at First Birth

    Science.gov (United States)

    Briley, Daniel A.; Harden, K. Paige; Tucker-Drob, Elliot M.

    2014-01-01

    Microevolutionary projections use empirical estimates of genetic covariation between physical or psychological phenotypes and reproductive success to forecast changes in the population distributions of those phenotypes over time. The validity of these projections depends on relatively consistent heritabilities of fertility-relevant outcomes and consistent genetic covariation between fertility and other physical or psychological phenotypes across generations. However, well-documented, rapidly changing mean trends in the level and timing of fertility may have been accompanied by differences in the genetic mechanisms of fertility. Using a sample of 933 adult twin pairs from the Midlife Development in the United States study, we demonstrate that genetic influences on completed fertility and age at first birth were trivial for the 1920 to 1935 birth cohort, but rose substantially for the 1936 to 1955 birth cohort. For the 1956 to 1970 birth cohort, genetic influences on completed fertility, but not age at first birth, persisted. Because the heritability of fertility is subject to change dynamically with the social context, it is difficult to project selection pressures or the rate at which selection will occur. PMID:25491394

  4. “Cultral” or “Kulturnichesky” Populism? (on the Meaning of Concepts in the History of Russian Populist Studies

    Directory of Open Access Journals (Sweden)

    Mokshin Gennadiy Nikolaevich

    2016-04-01

    Full Text Available The article is devoted to the origin and content of the concept of “cultural” and “kulturnichesky” populism in the Russian populist studies. Both terms appeared in the early twentieth century to refer to the right wing of the liberal populism. But they reflect different interpretations of the populist ideology: wide (of populism and narrow (of marxism. The term “cultural populism” (originated from “cultural work” reflects the desire of right-wing populists to create sociocultural prerequisites for changing the existing social order. The term “kulturnichesky populism” (from the German “kulturträger”, by the recognition of the Marxists themselves, was designed to discredit the populist program of social work in the countryside, allegedly aimed at reconciliation with reality. Most modern scholars following the tradition continue to use the concept of “kulturnichesky populism” and “cultural work”, sharing their biased interpretation. Not by chance in the scientific and educational literature, culturalpopulism direction is still associated with indifference with respect to political life and at the same time petty-bourgeois liberalism. According to the author, this approach not only distorts the ideas of populists-uplifters but also diminishes their contribution to the development of populist ideas of 1880-1890s. Therefore, for specialists in the history of legal populism it is recommended to use a more correct terms “cultural populism” and “cultural work”.

  5. 5 Assessment of fertility status.cdr

    African Journals Online (AJOL)

    Administrator

    coconut yield is generally related to the fertility status of the soil, a study was conducted to evaluate the fertility status of soils supporting ... Mean organic matter status 22.1 1.9 gkg was moderate. ... surface moisture drains down slope, which.

  6. Human Capital, Fertility and Growth

    OpenAIRE

    Galor, Oded

    2006-01-01

    The demographic transition that swept the world in the past 140 years has been identified as one of the prime forces in the transition from stagnation to growth. The unprecedented increase in population growth during the early stages of industrialization was ultimately reversed. The rise in the demand for human capital in the second phase of industrialization brought about a significant reduction in fertility rates and population growth in various regions of the world, enabling economies to c...

  7. Evaluation of the establishment of herd immunity in the population by means of serological surveys and vaccination coverage.

    Science.gov (United States)

    Plans-Rubió, Pedro

    2012-02-01

    The necessary herd immunity blocking the transmission of an infectious agent in the population is established when the prevalence of protected individuals is higher than a critical value, called the herd immunity threshold. The establishment of herd immunity in the population can be determined using the vaccination coverage and seroepidemiological surveys. The vaccination coverage associated with herd immunity (V(c)) can be determined from the herd immunity threshold and vaccine effectiveness. This method requires a vaccine-specific effectiveness evaluation, and it can be used only for the herd immunity assessment of vaccinated communities in which the infectious agent is not circulating. The prevalence of positive serological results associated with herd immunity can be determined from the herd immunity threshold, in terms of prevalence of antibodies (p(c)) and serological test performance. The herd immunity is established when the prevalence of antibodies is higher than pc. This method can be used to assess the establishment of herd immunity in different population groups, both when the infectious agent is circulating and when it is not possible to assess vaccine effectiveness. The herd immunity assessment in Catalonia, Spain, showed that the additional vaccination coverage required to establish herd immunity was 3-6% for measles, mump and varicella and 11% poliovirus type III in school children, 17-59% for diphtheria in youth and adults and 25-46% for persussis in school children, youth and adults.

  8. Fertilization in northern forests

    DEFF Research Database (Denmark)

    Hedwall, Per Ola; Gong, Peichen; Ingerslev, Morten

    2014-01-01

    resources into food, health and industrial products and energy. Fertilization in Sweden and Finland is currently practiced by extensive fertilization regimens where nitrogen fertilizers are applied once, or up to three times, during a rotation period, mainly in mature forest. This type of fertilization...

  9. Wealth, intelligence, politics and global fertility differentials.

    Science.gov (United States)

    Meisenberg, Gerhard

    2009-07-01

    Demographic trends in today's world are dominated by large fertility differentials between nations, with 'less developed' nations having higher fertility than the more advanced nations. The present study investigates whether these fertility differences are related primarily to indicators of economic development, the intellectual level of the population, or political modernity in the form of liberal democracy. Results obtained with multiple regression, path models and latent variable models are compared. Both log-transformed GDP and measures of intelligence independently reduce fertility across all methods, whereas the effects of liberal democracy are weak and inconsistent. At present rates of fertility and mortality and in the absence of changes within countries, the average IQ of the young world population would decline by 1.34 points per decade and the average per capita income would decline by 0.79% per year.

  10. In vivo and in vitro fertilizing capacity of cryopreserved European mouflon [Ovis gmelini musimon] spermatozoa used to restore genetically rare and isolated populations.

    Science.gov (United States)

    Berlinguer, Fiammetta; Leoni, Giovanni G; Bogliolo, Luisa; Bebbere, Daniela; Succu, Sara; Rosati, Irma; Ledda, Sergio; Naitana, Salvatore

    2005-02-01

    European mouflon sheep are an endangered species of ovidae residing primarily in the mountenous habitat of the islands of Sardinia and Corsica. The purpose of this study was to assess the fertilizing capacity of cryopreserved European mouflon spermatozoa after AI in synchronized mouflon and domestic ewes and after IVF in in vitro matured mouflon and domestic ewe oocytes collected by OPU technique. Domestic ram (Ovis aries) spermatozoa served as control. Semen was collected by artificial vagina from three mouflons and three domestic rams during the breeding season and was cryopreserved. At thawing, no significant differences in sperm viability were found between the wild and the domestic species (53.1 +/- 4.6% versus 56.0 +/- 4.7%) whereas the percentage of acrosome-intact sperm was lower in mouflon (55.5 +/- 4.6%) than in ram semen (62.7 +/- 3.1%; P mouflon and domestic ewes (5/11 versus 8/12) after 150 and 156 days of pregnancy, respectively. After two OPU sessions, 87 and 132 oocytes were collected from three hyperstimulated mouflon and three domestic ewes. Cryopreserved/thawed semen was inseminated with an endoscope into the uterus of corresponding species during the non-breeding season. The oocytes were matured and fertilized in vitro; 61/73 mouflon and 81/101 domestic ewe oocytes were found to be fertilized. From these, we obtained 6/61 and 17/81 blastocysts. After vitrification and thawing, the hatching rate showed no significant difference between mouflon and sheep blastocysts (4/6 versus 14/17). In conclusion, our data showed that cryopreserved mouflon spermatozoa can be successfully used to carry out a genuine and complete program of genetic restoration in small and isolated groups of European mouflons.

  11. [In vitro fertilization at the Erasme Hospital: 10 years and 1000 pregnancies later...].

    Science.gov (United States)

    Englert, Y; Van den Bergh, M; Delbaere, A; Devreker, F; Koenig, I; Hannes, M; Emiliani, S; Biramane, J; Vannin, A S; Govaerts, I; Holoye, A; Revelard, P

    1999-10-01

    This contribution summarize ten years of in vitro fertilization of clinical work. Activity growth, improvements of results (mean fertilization rate increased from 45% to 58%, fertilization failure dropped from 18% to 7%, pregnancy chances gains 9% to reach 44% per trial) and new treatments possibilities (severe male infertility) thanks to the ICSI technic were the major characteristics of this last ten years. The original anonymous oocyte donation program with donors permutation initiated as soon as 1990 has imposed itself due to it's exceptional efficiency with a pregnancy rate of 95% per oocyte pick up on a population of 46 donors and 145 recipient cycles. Thanks to the large population studied (4028 cycles, 1071 pregnancies), the tendencies in human fecundity (impact of age) and the risks linked to multiples pregnancies could be highlighted, stressing the importance of future developments presented in the other contributions following this general presentation of results.

  12. Toward replacement fertility in Egypt and Tunisia.

    Science.gov (United States)

    Eltigani, Eltigani E

    2009-09-01

    Egypt and Tunisia began their fertility transition at almost identical fertility levels and at roughly the same time period, yet the difference in the pace of decline has been such that the total fertility rate (TFR) in Tunisia reached replacement level by the year 2001, whereas the TFR in Egypt remains above three live births per woman. This article draws on the secondary literature and on several nationally representative surveys from the two countries between 1978 and 2005 to provide empirical evidence of the difference in the pace of fertility decline and to analyze the determinants of the differential. Findings include (a) variation across the two countries in the consistency of fertility decline among the segments of the population leading the transition; (b) that the success of each country's family planning program was influenced by the role of political leaders and the extent of the program's integration within socioeconomic development objectives; (c) that the impact of contraception on TFR decline became an important factor in the mid-1980s; and (d) that the greatest determinant of the discrepancy in the pace of fertility decline is the disparity in age at marriage, which rose more significantly in Tunisia than in Egypt. The latter finding indicates that reaching replacement fertility in Egypt hinges primarily on further declines in marital fertility, resulting from reduction of wanted fertility and from an expansion of family planning program coverage and improved efficiency of service delivery and use.

  13. Analysis of the effect of inoculum characteristics on the first stages of a growing yeast population in beer fermentations by means of an individual-based model.

    Science.gov (United States)

    Ginovart, M; Prats, C; Portell, X; Silbert, M

    2011-01-01

    The yeast Saccharomyces cerevisiae has a limited replicative lifespan. The cell mass at division is partitioned unequally between a larger, old parent cell and a smaller, new daughter cell. Industrial beer fermentations maintain and reuse yeast. At the end of fermentation a portion of the yeast is 'cropped' from the vessel for 'serial repitching'. Harvesting yeast may select a population with an imbalance of young and aged individuals, but the output of any bioprocess is dependent on the physiology of each single cell in the population. Unlike continuous models, individual-based modelling is an approach that considers each microbe as an individual, a unique and discrete entity, with characteristics that change throughout its life. The aim of this contribution is to explore, by means of individual-based simulations, the effects of inoculum size and cell genealogical age on the dynamics of virtual yeast fermentation, focussing on: (1) the first stages of population growth, (2) the mean biomass evolution of the population, (3) the rate of glucose uptake and ethanol production, and (4) the biomass and genealogical age distributions. The ultimate goal is to integrate these results in order to make progress in the understanding of the composition of yeast populations and their temporal evolution in beer fermentations. Simulation results show that there is a clear influence of these initial features of the inocula on the subsequent growth dynamics. By contrasting both the individual and global properties of yeast cells and populations, we gain insight into the interrelation between these two types of data, which helps us to deal with the macroscopic behaviour observed in experimental research.

  14. Pre-Transition Fertility in Asia : A Comparative-historical Approach

    OpenAIRE

    Saito, Osamu

    2006-01-01

    This paper questions the proposition that fertility was invariably high among populations beforethe fertility transition. By examining factors affecting pre-transition fertility based on the evidence fromJapan and India in the pre-World War II period, together with that from England and Germany in thetraditional period, it suggests that in most historical populations fertility was below the supposed biologicalmaximum, and that there was a pre-transition rising phase in fertility in countries ...

  15. Male fertility in cystic fibrosis.

    LENUS (Irish Health Repository)

    Chotirmall, S H

    2011-04-05

    Infertility rates among males with cystic fibrosis (CF) approximate 97%. No information is currently available within Ireland determining an understanding of fertility issues and the best methods of information provision to this specialized group. This study aimed to determine understanding and preferred approaches to information provision on fertility issues to Irish CF males. A Descriptive Study utilizing prospective coded questionnaires was mailed to a male CF cohort (n=50). Sections included demographics, fertility knowledge & investigation. Response rate was 16\\/50 (32%). All were aware that CF affected their fertility. More than two-thirds (n=11) were able to provide explanations whilst only one-third (n=5) provided the correct explanation. Significant numbers stated thoughts of marriage and a future family. Half have discussed fertility with a healthcare professional (HCP). Mean age of discussion was 21.9 years. One third preferred an earlier discussion. The commonest first source for information was written material which was also the preferred source. Three-quarters requested further information preferring again, written material. Significant gaps in sex education of Irish CF males exist. Discussion should be initiated by HCPs and centre-directed written material devised to address deficiencies.

  16. Cancer and fertility : strategies to preserve fertility

    NARCIS (Netherlands)

    Diedrich, K.; Fauser, B. C. J. M.; Devroey, P.

    2011-01-01

    Fertility preservation is a key component of cancer management in young people. The Fourth Evian Annual Reproduction Workshop Meeting was held in April 2009 to discuss cancer and fertility in young adults. Specialists in oncology, assisted reproduction, embryology and clinical genetics presented pub

  17. Cancer and fertility : strategies to preserve fertility

    NARCIS (Netherlands)

    Diedrich, K.; Fauser, B. C. J. M.; Devroey, P.

    Fertility preservation is a key component of cancer management in young people. The Fourth Evian Annual Reproduction Workshop Meeting was held in April 2009 to discuss cancer and fertility in young adults. Specialists in oncology, assisted reproduction, embryology and clinical genetics presented

  18. Cohort Fertility Patterns in the Nordic Countries

    DEFF Research Database (Denmark)

    Andersson, Gunnar; Rønsen, Marit; Knudsen, Lisbeth B.

    cumulated and completed fertility of Nordic birth cohorts based on the childbearing histories of women born in 1935 and later derived from the population registers of Denmark, Finland, Norway and Sweden. We further explore childbearing behaviour by women’s educational attainment. The results show remarkable...... at similar ages are compared. Country differences in fertility outcome are generally rather low. Childlessness is highest in Finland and lowest in Norway, and the educational differentials are largest in Norway. Despite such differences, the cohort analyses in many ways support the notion of a common Nordic......Previous analyses of period fertility suggest that the trends of the Nordic countries are sufficiently similar to speak of a common "Nordic fertility regime". We investigate whether this assumption can be corroborated by comparing cohort fertility patterns in the Nordic countries. We study...

  19. Cohort Fertility Patterns in the Nordic Countries

    DEFF Research Database (Denmark)

    Andersson, Gunnar; Rønsen, Marit; Knudsen, Lisbeth B.

    2009-01-01

    cumulated and completed fertility of Nordic birth cohorts based on the childbearing histories of women born in 1935 and later derived from the population registers of Denmark, Finland, Norway, and Sweden. We further explore childbearing behaviour by women's educational attainment. The results show......Previous analyses of period fertility suggest that the trends of the Nordic countries are sufficiently similar to speak of a common "Nordic fertility regime". We investigate whether this assumption can be corroborated by comparing cohort fertility patterns in the Nordic countries. We study...... remarkable similarities in postponement and recuperation between the countries. Median childbearing age is about 2-3 years higher in the 1960-64 cohort than in the 1950-54 cohort, but the younger cohort recuperates the fertility level of the older cohort at ages 30 and above. A similar pattern...

  20. Environmentally friendly slow-release nitrogen fertilizer.

    Science.gov (United States)

    Ni, Boli; Liu, Mingzhu; Lü, Shaoyu; Xie, Lihua; Wang, Yanfang

    2011-09-28

    To sustain the further world population, more fertilizers are required, which may become an environmental hazard, unless adequate technical and socioeconomic impacts are addressed. In the current study, slow-release formulations of nitrogen fertilizer were developed on the basis of natural attapulgite (APT) clay, ethylcellulose (EC) film, and sodium carboxymethylcellulose/hydroxyethylcellulose (CMC/HEC) hydrogel. The structural and chemical characteristics of the product were examined. The release profiles of urea, ammonium sulfate, and ammonium chloride as nitrogen fertilizer substrates were determined in soil. To further compare the release profiles of nitrogen from different fertilizer substrates, a mathematical model for nutrient release from the coated fertilizer was applied to calculate the diffusion coefficient D. The influence of the product on water-holding and water-retention capacities of soil was determined. The experimental data indicated that the product can effectively reduce nutrient loss, improve use efficiency of water, and prolong irrigation cycles in drought-prone environments.

  1. Age- and Gender-Related Mean Hearing Threshold in a Highly-Screened Population: The Korean National Health and Nutrition Examination Survey 2010-2012.

    Directory of Open Access Journals (Sweden)

    Yun Hwi Park

    Full Text Available In evaluating hearing disability in medicolegal work, the apportionment of age- and gender-related sensorineural hearing loss should be considered as a prior factor, especially for the elderly. However, in the literature written in the English language no studies have reported on the age- and gender-related mean hearing threshold for the South Korean population.This study aimed to identify the mean hearing thresholds in the South Korean population to establish reference data and to identify the age- and gender-related characteristics.This study is based on the Korea National Health and Nutrition Examination Survey (KNHANES 2010-2012, which was conducted by the Korean government, the data of which was disclosed to the public. A total of 15,606 participants (unweighted representing 33,011,778 Koreans (weighted with normal tympanic membrane and no history of regular or occupational noise exposure were selected and analyzed in this study. The relationship between the hearing threshold level and frequency, age, and gender was investigated and analyzed in a highly-screened population by considering the sample weights of a complex survey design.A gender ratio difference was found between the unweighted and the weighted designs: male:female, 41.0%: 59.0% (unweighted, participants vs. 47.2%:52.8% (weighted, representing population. As age increased, the hearing threshold increased for all frequencies. Hearing thresholds of 3 kHz, 4 kHz, and 6 kHz showed a statistical difference between both genders for people older than 30, with the 4 kHz frequency showing the largest difference. This paper presents details about the mean hearing threshold based on age and gender.The data from KNHANES 2010-2012 showed gender differences at hearing thresholds of 3 kHz, 4 kHz, and 6 kHz in a highly-screened population. The most significant gender difference in relation to hearing threshold was observed at 4 kHz. The hearing thresholds at all of the tested frequencies

  2. Age- and Gender-Related Mean Hearing Threshold in a Highly-Screened Population: The Korean National Health and Nutrition Examination Survey 2010-2012.

    Science.gov (United States)

    Park, Yun Hwi; Shin, Seung-Ho; Byun, Sung Wan; Kim, Ju Yeon

    2016-01-01

    In evaluating hearing disability in medicolegal work, the apportionment of age- and gender-related sensorineural hearing loss should be considered as a prior factor, especially for the elderly. However, in the literature written in the English language no studies have reported on the age- and gender-related mean hearing threshold for the South Korean population. This study aimed to identify the mean hearing thresholds in the South Korean population to establish reference data and to identify the age- and gender-related characteristics. This study is based on the Korea National Health and Nutrition Examination Survey (KNHANES) 2010-2012, which was conducted by the Korean government, the data of which was disclosed to the public. A total of 15,606 participants (unweighted) representing 33,011,778 Koreans (weighted) with normal tympanic membrane and no history of regular or occupational noise exposure were selected and analyzed in this study. The relationship between the hearing threshold level and frequency, age, and gender was investigated and analyzed in a highly-screened population by considering the sample weights of a complex survey design. A gender ratio difference was found between the unweighted and the weighted designs: male:female, 41.0%: 59.0% (unweighted, participants) vs. 47.2%:52.8% (weighted, representing population). As age increased, the hearing threshold increased for all frequencies. Hearing thresholds of 3 kHz, 4 kHz, and 6 kHz showed a statistical difference between both genders for people older than 30, with the 4 kHz frequency showing the largest difference. This paper presents details about the mean hearing threshold based on age and gender. The data from KNHANES 2010-2012 showed gender differences at hearing thresholds of 3 kHz, 4 kHz, and 6 kHz in a highly-screened population. The most significant gender difference in relation to hearing threshold was observed at 4 kHz. The hearing thresholds at all of the tested frequencies worsened with

  3. Semen quality in sub-fertile range for a significant proportion of young men from the general German population: a co-ordinated, controlled study of 791 men from Hamburg and Leipzig

    DEFF Research Database (Denmark)

    Paasch, U.; Salzbrunn, A.; Glander, H.J.

    2008-01-01

    Population studies have shown that a high proportion of Nordic men may have so poor semen quality that they can be classified as sub-fertile according to international standards. A question is whether the Nordic data are specific for the Nordic countries or they should be seen as an expression...... of a general trend in Europe. We therefore carried out a prospective study of semen quality of young men raised in the former East Germany (Leipzig) and West Germany (Hamburg). To enable inter-regional comparisons, we utilized a common European research protocol previously used in studies in the Nordic......--July 2004, and in Leipzig July 2003--April 2005. No significant differences were observed in sperm concentration (median 46, 42, and 44 million/mL for men from Hamburg, Leipzig and the combined Hamburg-Leipzig group respectively) or total sperm count (154,141 and 149 million), whereas the differences...

  4. Age and Fertility

    Science.gov (United States)

    ... method of assisted reproduction that involves combining an egg with sperm in a laboratory dish. If the egg fertilizes ... produced by the testes that fertilize a woman’s egg. The sperm head carries genetic material (chromosomes), the midpiece produces ...

  5. Plant fertilizer poisoning

    Science.gov (United States)

    Plant fertilizers and household plant foods are used to improve plant growth. Poisoning can occur if someone swallows these products. Plant fertilizers are mildly poisonous if small amounts are swallowed. ...

  6. Fertility Clinic Success Rates

    Science.gov (United States)

    ... and Autism 2013 Assisted Reproductive Technology Fertility Clinic Success Rates Report Recommend on Facebook Tweet Share Compartir 2013 ART Fertility Clinic Success Rates Report [PDF - 1MB] Bookmarks and thumbnails are ...

  7. In vitro fertilization (IVF)

    Science.gov (United States)

    ... medlineplus.gov/ency/article/007279.htm In vitro fertilization (IVF) To use the sharing features on this page, please enable JavaScript. In vitro fertilization (IVF) is the joining of a woman's egg ...

  8. Phospholipid fatty acid patterns of microbial communities in paddy soil under different fertilizer treatments

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qi-chun; WANG Guang-huo; YAO Huai-ying

    2007-01-01

    The microbial communities under irrigated rice cropping with different fertilizer treatments, including control (CK), PK, NK, NP, NPK fertilization, were investigated using phospholipid fatty acid (PLFA) profile method. The results of this study revealed that the fertilizer practice had an impact on the community structure of specific microbial groups. The principal components analysis (PCA) showed that proportion of the actinomycete PLFAs (10Me 18:0 and 10Me 16:0) were the lowest in the PK treatment and the highest in the NPK treatment, which means that soil nitrogen status affected the diversity of actinomycetes, whereas nitrogen cycling was related to the actinomycets. Under CK treatment, the ratio of Gram-positive to Gram-negative bacteria was lower compared with that in fertilizer addition treatments, indicating that fertilizer application stimulated Gram-positive bacterial population in paddy soil. The fatty acid 18:2ω6, 9, which is considered to be predominantly of fungal origin, was at low level in all the treatments. The ratio of cy19:0 to 18:1ω7, which has been proposed as an indicator of stress conditions, decreased in PK treatment. Changes of soil microbial community under different fertilizer treatments of paddy soil were detected in this study; however, the causes that lead to changes in the microbial community still needs further study.

  9. Proximate Determinants of Fertility in Zambia: Analysis of the 2007 Zambia Demographic and Health Survey

    Directory of Open Access Journals (Sweden)

    Mumbi Chola

    2016-01-01

    Full Text Available The role of proximate determinants in influencing fertility has been well documented worldwide. Bongaarts’ aggregate model of the proximate determinants (which focuses on marriage, contraception, abortion, and sterility has been widely used to analyse the influence of proximate determinants on fertility. In Zambia, however, there is limited understanding of their effects. Therefore, the aim of this study was to examine the effect of proximate determinants of fertility in Zambia using Bongaarts’ model. This was a cross-sectional analysis of women’s data from the 2007 Zambia Demographic and Health Survey (ZDHS. A total of 7,146 women aged 15 to 49 years participated in the ZDHS. Bongaarts’ model was employed in the data analysis. Results showed that, overall, mean age was 27.8 years and rural-urban distribution was 56% and 44%, respectively. Marriage (40% and postpartum infecundity (22% accounted for the largest inhibiting effect on natural fertility from its biological maximum of 19.10. Contraception use accounted for only 3%. Therefore, in order to manage fertility in Zambia, policies and programmes should consider the effects of marriage, postpartum infecundity, and contraception on fertility. Without such targeted interventions, managing and maintaining population growth will remain a challenge in Zambia.

  10. Assessment of testicular volume: A comparison of fertile and sub-fertile West African men

    Directory of Open Access Journals (Sweden)

    K.H. Tijani

    2014-09-01

    Conclusion: Testicular volume on scrotal ultrasound correlates well with severity of oligospermia in men with sub-fertility. While the critical mean testicular volume necessary for adequate spermatogenesis has not been determined, it appears there is an optimal testicular volume of 18–20 ml at which spermatogenesis is at its peak in sub-fertile Nigerian men.

  11. Low body mass index compromises live birth rate in fresh transfer in vitro fertilization cycles: a retrospective study in a Chinese population.

    Science.gov (United States)

    Cai, Jiali; Liu, Lanlan; Zhang, Junwen; Qiu, Huiling; Jiang, Xiaoming; Li, Ping; Sha, Aiguo; Ren, Jianzhi

    2017-02-01

    To evaluate the effects of low body mass index (BMI) on in vitro fertilization (IVF) outcomes in fresh transfer cycles. Retrospective cohort study. University-affiliated hospital. A total of 4,798 cycles with conventional stimulation and fresh transfer in a single IVF center during the period 2013-2014. Low BMI (Live birth rate per fresh embryo transfer. Low BMI was associated with reduced live birth rates and increased miscarriage rates compared with normal weight, controlling for important covariates known to influence IVF outcomes. Patient age was the most potent confounder, causing a 10.5% reduction in the odds ratio (OR) for live birth between the groups compared. When an interaction term (age × BMI) was introduced, the OR for live birth was reduced in cycles of those aged ≥35 years compared with cycles of those aged 28-34 years, whereas the change in OR between cycles in those aged <28 and cycles in those aged 28-34 years was insignificant. Low BMI is associated with negative outcomes in fresh transfer cycles, especially for women of advanced age. Copyright © 2016 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  12. Cohort Fertility Patterns in the Nordic Countries

    Directory of Open Access Journals (Sweden)

    Gunnar Andersson

    2009-04-01

    Full Text Available Previous analyses of period fertility suggest that the trends of the Nordic countries are sufficiently similar to speak of a common "Nordic fertility regime". We investigate whether this assumption can be corroborated by comparing cohort fertility patterns in the Nordic countries. We study cumulated and completed fertility of Nordic birth cohorts based on the childbearing histories of women born in 1935 and later derived from the population registers of Denmark, Finland, Norway, and Sweden. We further explore childbearing behaviour by women's educational attainment. The results show remarkable similarities in postponement and recuperation between the countries and very small differences in completed fertility across educational groups. Median childbearing age is about 2-3 years higher in the 1960-64 cohort than in the 1950-54 cohort, but the younger cohort recuperates the fertility level of the older cohort at ages 30 and above. A similar pattern of recuperation can be observed for highly educated women as compared to women with less education. An interesting finding is that of a positive relationship between educational level and the final number of children when women who become mothers at similar ages are compared. Country differences in fertility outcome are generally rather low. Childlessness is highest in Finland and lowest in Norway, and the educational differentials are largest in Norway. Despite such differences, the cohort analyses in many ways support the notion of a common Nordic fertility regime.

  13. Proximate determinants of fertility in peninsular Malaysia.

    Science.gov (United States)

    Tey, Nai Peng; Ng, Sor Tho; Yew, Siew Yong

    2012-05-01

    The continuing decline in fertility despite a contraction in contraceptive use in Peninsular Malaysia since the mid-1980s has triggered considerable interest in the reasons behind this phenomenon, such as increase in abortion, sterility, and out-of-wedlock pregnancy. Fertility decline has been attributed to rapid socioeconomic development, which can only influence fertility through the intermediate variables. Application of vital statistics, population census, and survey data of Peninsular Malaysia on Bongaarts's model vindicates that marriage postponement and contraceptive use are the 2 most important proximate determinants of fertility, but the effects are not uniform across the ethnic groups. For instance, the predicted total fertility rate for Chinese and Malays are 2.9 and 1.6, respectively, compared with the observed level of 3.0 and 1.9. Postpartum infecundability and abortion also play a part in explaining ethnic fertility differentials. The fertility inhibiting effects of these proximate determinants have significant implications on reproductive health and future population growth.

  14. Cancer and fertility: strategies to preserve fertility.

    Science.gov (United States)

    Diedrich, K; Fauser, B C J M; Devroey, P

    2011-03-01

    Fertility preservation is a key component of cancer management in young people. The Fourth Evian Annual Reproduction Workshop Meeting was held in April 2009 to discuss cancer and fertility in young adults. Specialists in oncology, assisted reproduction, embryology and clinical genetics presented published data and ongoing research on cancer and fertility, with particular focus on strategies to preserve fertility. This report is based on the expert presentations and group discussions, supplemented with publications from literature searches and the authors' knowledge. Fertility preservation should be considered for all young people undergoing potentially gonadotoxic cancer treatment. A variety of options are required to facilitate safe and effective fertility preservation for individual patients. Sperm banking is a simple and low-cost intervention. Embryo cryopreservation is the only established method of female fertility preservation. Oocyte cryopreservation offers a useful option for women without a male partner. Emergency ovarian stimulation and cryopreservation of ovarian tissue (followed by tissue transplantation or in-vitro maturation of oocytes) are experimental techniques for women who require urgent cancer treatment. Further prospective studies are required to validate cryopreservation of oocytes and ovarian tissue, in-vitro maturation of oocytes and new vitrification techniques and to identify any long-term sequelae of slow freezing of embryos.

  15. 几个总体均值函数的鞍点逼近%Saddlepoint Approximations for Function of Means from Several Populations

    Institute of Scientific and Technical Information of China (English)

    邢炳义; 李泽慧

    2002-01-01

    Saddlepoint approximations for marginal tail probabilities for a real-valued function of vector means fromseveral populations are developed. The approximations are then shown to give great numerical accuracy, whichare demonstrated in some numerical examples. Application to the bootstrap is also considered in order to avoidintensive Monte Carlo simulations.%本文发展了儿个总体的均值向量的函数的尾部概率的鞍点逼近方法,并应用它丁Bootstrap估计中,以代替Monto Carlo模拟,一些数值例子说明了其近似精度.

  16. Playing the Fertility Game at Work

    DEFF Research Database (Denmark)

    Ciliberto, Federico; Miller, Amalia Rebecca; Nielsen, Helena Skyt

    2016-01-01

    We study workplace peer effects in fertility decisions using a game theory model of strategic interactions among coworkers that allows for multiple equilibria. Using register-based data on fertile-aged women working in medium sized establishments in Denmark, we uncover negative average peer effects....... Allowing for heterogeneous effects by worker type, we find that positive effects dominate across worker types defined by age or education. Negative effects dominate within age groups and among low-education types. Policy simulations show that these estimated effects make the distribution of where women...... work an important consideration, beyond simply if they work, in predicting population fertility....

  17. 蚯蚓种群特征及其对土壤肥力指示作用研究%Research on Earthworm Population Characteristics and its Indicating Function to Soil Fertility

    Institute of Scientific and Technical Information of China (English)

    张宁; 廖燕; 孙振钧; 王冲; 朱君君

    2011-01-01

    采用田间调查方法,对华北盐渍改造区7种土地利用方式下的蚯蚓种群特征的变化进行详细调查,分析土地利用方式对蚯蚓种群造成的影响,同时探讨了不同土地利用方式下土壤肥力的差异,并对蚯蚓种群特征与土壤化生物学性质的相关性进行研究。结果表明:蚯蚓的物种数、种群密度、生物量、年龄结构及Shannon-Weiner(H’)多样性指数,与土壤化学及生物学性质的大部分指标具有显著的相关性,对不同土地利用方式下的土壤肥力状况有一定的响应关系。%Field survey was adopted to investigate the earthworm species in alkali land in Quzhou country,Hebei Province.In this paper,five indicators including earthworm species,population density,biomass,age-structure and H',which can be used to indicate the biodiversity patterns of earthworm were employed to investigate the effects of different land use types on the earthworm biodiversity patterns.The relationships between land use types and soil characters were discussed after measuring soil character under 7 ways of land use.The results showed that,the number of earthworm species,its population density,biomass,age structure and diversity index were obviously related to most indices of the soil chemical and biological characteristics,and also responding to soil fertility of different land use.With earthworm population characteristics as the evaluation index,the results corresponded with that of index evaluation using soil biological characteristics and soil chemistry.Therefore,it is practical to synthetically appraise soil biological fertility using earthworm population characteristics.

  18. Stabilization process of human population: a descriptive approach.

    Science.gov (United States)

    Kayani, A K; Krotki, K J

    1981-01-01

    An attempt is made to inquire into the process of stabilization of a human population. The same age distribution distorted by past variations in fertility is subjected to several fixed schedules of fertility. The schedules are different from each other monotonically over a narrow range. The primary concern is with the process, almost year by year, through which the populations become stable. There is particular interest in the differential impact in the same original age distribution of the narrowly different fixed fertility schedules. The exercise is prepared in 3 stages: general background of the process of stabilization; methodology and data used; and analysis and discussion of the stabilization process. Among the several approaches through which the analysis of stable population is possible, 2 are popular: the integral equation and the projection matrix. In this presentation the interest is in evaluating the effects of fertility on the stabilization process of a population. Therefore, only 1 initial age distribution and only 1 life table but a variety of narrowly different schedules of fertility have been used. Specifically, the U.S. 1963 female population is treated as the initial population. The process of stabilization is viewed in the light of the changes in the slopes between 2 successive age groups of an age distribution. A high fertility schedule with the given initial age distribution and mortality level overcomes the oscillations more quickly than the low fertility schedule. Simulation confirms the intuitively expected positive relationship between the mean of the slope and the level of fertility. The variance of the slope distribution is an indicator of the aging of the distribution.

  19. Policy Implications of the Variations in Ghana's Fertility Transition ...

    African Journals Online (AJOL)

    ... the process among geographic and socioeconomic subgroups of the population. ... socioeconomic subgroups of the population and the administrative regions. ... fertility transition in the country must therefore address this underlying factor.

  20. The economics of fertility.

    Science.gov (United States)

    Loraine, J A

    1982-01-01

    The statement that economics and fertility are closely interrelated is a truism. The classical economists--Adam Smith, Thomas Malthus, Karl Marx, John Stuart Mill and John Maynard Keynes appreciated this fact, and their reviews are recounted and their prescience is assessed. Adam Smith (1723-1790) was primarily concerned with the desire of humankind to better his/her material conditions. Although he did not put forward a specific population policy, the tenet of his writing is pronatalist. Economic advantages would accrue to parents by the production of many children. Yet, underneath Smith's optimism, there was an apocalyptic vision of the distant future, i.e., the "steady state" when resources would be depleted or near exhaustion, when capital accumulation would have ceased, and living standards would be dropping vertiginously. In his 1st "Essay on Population" Malthus maintained that "the power of population is infinitely greater than the power of the earth to produce subsistence of men." Malthus can be complimented on his prescience. There is little question that the planet of today is grossly overpopulated and that a great gulf exists between numbers of people and their aspirations and the resources which the earth can provide for them. Malthus was particularly concerned about the population food dilemma, and that is still much in evidence in 1982. 2 concomitants of overpopulation--excessive urbanization and joblessness--could not be foreseen by Malthus. Marx did not deny the basic tenet promulgated by Malthus but to him this was simply an artifact of capitalist society which required "enormous reserves of proletarians" in order to maintain its odius system. Officially Communist governments remain in a Marxist straitjacket regarding the population issue. Mills approach was strongly antinatalist; he saw little need for an increase in human numbers. Mills was concerned that because of unlimited population growth and wealth the earth would lose much of its

  1. The "amazing" fertility decline: Islam, economics, and reproductive decision making among working-class Moroccan women.

    Science.gov (United States)

    Hughes, Cortney L

    2011-12-01

    Often it is understood that Islam prohibits family planning because the Qur'an does not explicitly address contraception. Public health and development officials have recently congratulated the Muslim world for decreases in fertility given the supposed constraints placed on reproductive healthcare by Islam, while popular culture writers have warned the West of threats by young Muslims if the population goes uncontrolled. This article draws on data collected through interviews with working-class women seeking reproductive healthcare at clinics in Rabat, Morocco, and with medical providers to challenge the link between Islamic ideology and reproductive practices and the correlation among Islam, poverty, and fertility. Morocco, a predominantly Muslim country, has experienced a dramatic decrease in fertility between the 1970s and today. I argue that patients and providers give new meanings to modern reproductive practices and produce new discourses of reproduction and motherhood that converge popular understandings of Islam with economic conditions of the Moroccan working class.

  2. Multiscale Regional Formula Fertilization Considering Environment Information Incompleteness

    Institute of Scientific and Technical Information of China (English)

    Qianqian ZHANG; Yan LIANG

    2015-01-01

    Conventional formula fertilization tends to calculate regional rate of fertilizer application by means of analyzing spatial distribution of regional cultivated land productivity combined with experiment data. However,as environment information of cultivated land is incomplete due to limitation of traditional cultivated land management technology and data acquisition,uncertainty of rate of fertilizer makes it hard to define the interval of formula fertilization and support the regional fertilization task. With the technique of spatial analysis and multiscale uncertainty theory,conventional fertilization can be optimized. Four steps are involved to calculate regional formula fertilization interval based on conventional formula fertilization:( i) To simulate cultivated land productivity according to EGLSN Model,and make it crop target field;( ii) To determine rate of fertilizer according to target field to define cultivated land productivity fertilizer interval and mid-value;( iii) To define region fertilizer interval length and value of region varying with scales as environment information becomes complete gradually;( iv) To apply block fertilizer combined with conventional formula by soil testing. Multiscale optimizing formula fertilization system has been established by using the Arc Engine as a platform to integrate the methods,which is applied in Xinjiang County,Shanxi Province,in order to optimize the existing fertilization formula in study area. It showed that the optimized formula fertilization had more spatial details of productivity than the original one.And the new method is available to support formula fertilization in any region or the block with uncertain environment information. It is therefore concluded that the proposed method has the potential for popularity,which provides a multiscale,multiple-factor and standardized formula fertilization method.

  3. O ensino de contrôle da fertilidade e de problemas populacionais em escolas médicas brasileiras The teaching of fertility and population problems at Brazilian schools of medicine

    Directory of Open Access Journals (Sweden)

    João Yunes

    1970-06-01

    Full Text Available Foi realizada em 1967 uma pesquisa sôbre o ensino do contrôle da fertilidade e de problemas populacionais em 42 escolas médicas brasileiras. Verificou-se, que das 22 escolas médicas que responderam ao questionário, 14 ensinavam o contrôle da fertilidade e 6 expressaram interêsse em iniciar tal ensino. Grande interêsse foi demonstrado nos aspectos sociais e demográficos e grande ênfase foi dada para a indicação do contrôle da fertilidade nos casos de "enfermidade ou agravamentos físicos", assim como para "problemas psiquiátricos". A viabilidade de clinicas para o ensino aos estudantes de medicina em técnicas contraceptivas foi em geral muito baixa. O uso de pílulas anovulatórias e o método do ritmo foram os contraceptivos preferidos para o ensino.A survey of teaching about fertility regulation and population problems in the 42 medical schools of Brazil was carried out in 1967. Fertility regulation was taught in 14 of the 22 schools; which replied, and 6 expressed intention to start such teaching. Interest in demography and social aspects was higher, and great emphasis was placed on giving contraceptive help for "physical illnes" or "impairment" and "phychiatric problems". Availability of clinical facilities for teaching students to give contraceptive services; was generally low. Pill and the rythm method were the preferred contraceptive for teaching medical students.

  4. Socio-economic status and fertility decline: Insights from historical transitions in Europe and North America.

    Science.gov (United States)

    Dribe, Martin; Breschi, Marco; Gagnon, Alain; Gauvreau, Danielle; Hanson, Heidi A; Maloney, Thomas N; Mazzoni, Stanislao; Molitoris, Joseph; Pozzi, Lucia; Smith, Ken R; Vézina, Hélène

    2017-03-01

    The timings of historical fertility transitions in different regions are well understood by demographers, but much less is known regarding their specific features and causes. In the study reported in this paper, we used longitudinal micro-level data for five local populations in Europe and North America to analyse the relationship between socio-economic status and fertility during the fertility transition. Using comparable analytical models and class schemes for each population, we examined the changing socio-economic differences in marital fertility and related these to common theories on fertility behaviour. Our results do not provide support for the hypothesis of universally high fertility among the upper classes in pre-transitional society, but do support the idea that the upper classes acted as forerunners by reducing their fertility before other groups. Farmers and unskilled workers were the latest to start limiting their fertility. Apart from these similarities, patterns of class differences in fertility varied significantly between populations.

  5. Promoting bio-fertilizers in Indian agriculture

    OpenAIRE

    Nilabja Ghosh

    2003-01-01

    The green revolution brought impressive gains in food production but with insufficient concern for sustainability. In India the availability and affordability of fossil fuel based chemical fertilizers at the farm level have been ensured only through imports and subsidies. Dependence on chemical fertilizers for future agricultural growth would mean further loss in soil quality, possibilities of water contamination and unsustainable burden on the fiscal system. The Government of India has been ...

  6. Fertilization in northern forests

    DEFF Research Database (Denmark)

    Hedwall, Per Ola; Gong, Peichen; Ingerslev, Morten

    2014-01-01

    resources into food, health and industrial products and energy. Fertilization in Sweden and Finland is currently practiced by extensive fertilization regimens where nitrogen fertilizers are applied once, or up to three times, during a rotation period, mainly in mature forest. This type of fertilization......Forests of northern ecosystems respond slowly to management activities and the possibilities to increase the growth in a short-term perspective and meet swift increases in society's demand for biomass are small. An exception among the silvicultural measures is fertilization which can be applied...... in combination with present management systems and, almost instantly, enhances forest productivity. There may, however, be both economic and environmental constraints to large-scale applications of fertilizers in forest. Here we review the literature concerning biomass production of forests under different...

  7. Fertility Preservation for Female

    Institute of Scientific and Technical Information of China (English)

    Jack Huang; Seang Lin Tan; Ri-Cheng Chian

    2006-01-01

    Preservation of female fertility is an important issue today. However, there are few effective clinical options for preserving female fertility. Firstly, conventional in vitro fertilization (IVF) followed by embryo cryopreservation is an accepted procedure but is not applicable to all women. Embryo freezing is suitable only for women with a male partner and may not be acceptable to some patients due to moral and religious reasons. Ovarian tissue freezing is another option of female fertility preservation but is an invasive procedure and the efficacy of this technique remains to be determined.Oocyte cryopreservation is also method for fertility preservation. Egg freezing is minimally invasive and can avoid the ethical and moral concerns related to cryopreservation of embryos. However, conventional slow freezing/rapid thawing methods are associated with low survival of oocytes. Recent development in vitrification of oocytes appears promising. Therefore, vitrification of unfertilized eggs may be a novel method to preserve female fertility.

  8. Fertilization in echinoderms.

    Science.gov (United States)

    Santella, Luigia; Vasilev, Filip; Chun, Jong T

    2012-08-31

    For more than 150 years, echinoderm eggs have served as overly favored experimental model systems in which to study fertilization. Sea urchin and starfish belong to the same phylum and thus share many similarities in their fertilization patterns. However, several subtle but fundamental differences do exist in the fertilization of sea urchin and starfish, reflecting their phylogenetic bifurcation approximately 500 million years ago. In this article we review some of the seminal and recent findings that feature similarities and differences in sea urchin and starfish at fertilization.

  9. How contemporary human reproductive behaviors influence the role of fertility-related genes: the example of the p53 gene.

    Directory of Open Access Journals (Sweden)

    Rosa Maria Corbo

    Full Text Available Studies on human fertility genes have identified numerous risk/protective alleles involved in the occurrence of reproductive system diseases causing infertility or subfertility. Investigations we carried out in populations at natural fertility seem to suggest that the clinical relevance that some fertility genes are now acquiring depends on their interaction with contemporary reproductive behaviors (birth control, delayed childbearing, and spacing birth order, among others. In recent years, a new physiological role in human fertility regulation has emerged for the tumor- suppressor p53 gene (P53, and the P53 Arg72Pro polymorphism has been associated with recurrent implantation failure in humans. To lend support to our previous observations, we examined the impact of Arg72Pro polymorphism on fertility in two samples of Italian women not selected for impaired fertility but collected from populations with different (premodern and modern reproductive behaviors. Among the women at near-natural fertility (n = 98, the P53 genotypes were not associated with different reproductive efficiency, whereas among those with modern reproductive behaviors (n = 68, the P53 genotypes were associated with different mean numbers of children [Pro/Pro = 0.75fertility genes may have become "detrimental" following exposure to modern reproductive patterns and might therefore be associated with reduced reproductive success. Set within an evolutionary framework, this change could lead to the selection of a set of gene variants fitter to current reproductive behaviors as the

  10. Population Size Predicts Lexical Diversity, but so Does the Mean Sea Level --Why It Is Important to Correctly Account for the Structure of Temporal Data.

    Science.gov (United States)

    Koplenig, Alexander; Müller-Spitzer, Carolin

    2016-01-01

    In order to demonstrate why it is important to correctly account for the (serial dependent) structure of temporal data, we document an apparently spectacular relationship between population size and lexical diversity: for five out of seven investigated languages, there is a strong relationship between population size and lexical diversity of the primary language in this country. We show that this relationship is the result of a misspecified model that does not consider the temporal aspect of the data by presenting a similar but nonsensical relationship between the global annual mean sea level and lexical diversity. Given the fact that in the recent past, several studies were published that present surprising links between different economic, cultural, political and (socio-)demographical variables on the one hand and cultural or linguistic characteristics on the other hand, but seem to suffer from exactly this problem, we explain the cause of the misspecification and show that it has profound consequences. We demonstrate how simple transformation of the time series can often solve problems of this type and argue that the evaluation of the plausibility of a relationship is important in this context. We hope that our paper will help both researchers and reviewers to understand why it is important to use special models for the analysis of data with a natural temporal ordering.

  11. Population Size Predicts Lexical Diversity, but so Does the Mean Sea Level – Why It Is Important to Correctly Account for the Structure of Temporal Data

    Science.gov (United States)

    Koplenig, Alexander; Müller-Spitzer, Carolin

    2016-01-01

    In order to demonstrate why it is important to correctly account for the (serial dependent) structure of temporal data, we document an apparently spectacular relationship between population size and lexical diversity: for five out of seven investigated languages, there is a strong relationship between population size and lexical diversity of the primary language in this country. We show that this relationship is the result of a misspecified model that does not consider the temporal aspect of the data by presenting a similar but nonsensical relationship between the global annual mean sea level and lexical diversity. Given the fact that in the recent past, several studies were published that present surprising links between different economic, cultural, political and (socio-)demographical variables on the one hand and cultural or linguistic characteristics on the other hand, but seem to suffer from exactly this problem, we explain the cause of the misspecification and show that it has profound consequences. We demonstrate how simple transformation of the time series can often solve problems of this type and argue that the evaluation of the plausibility of a relationship is important in this context. We hope that our paper will help both researchers and reviewers to understand why it is important to use special models for the analysis of data with a natural temporal ordering. PMID:26938719

  12. Fertilizer Use and Water Quality.

    Science.gov (United States)

    Reneau, Fred; And Others

    This booklet presents informative materials on fertilizer use and water quality, specifically in regard to environmental pollution and protection in Illinois. The five chapters cover these topics: Fertilizer and Water Quality, Fertilizer Use, Fertilizers and the Environment, Safety Practices, and Fertilizer Management Practices. Key questions are…

  13. Fertilizer Use and Water Quality.

    Science.gov (United States)

    Reneau, Fred; And Others

    This booklet presents informative materials on fertilizer use and water quality, specifically in regard to environmental pollution and protection in Illinois. The five chapters cover these topics: Fertilizer and Water Quality, Fertilizer Use, Fertilizers and the Environment, Safety Practices, and Fertilizer Management Practices. Key questions are…

  14. Cadmium in insects after ash fertilization

    Institute of Scientific and Technical Information of China (English)

    Martin Lodenius; Jussi Josefsson; Kari Heli(o)vaara; Esa Tulisalo; Matti Nummelin

    2009-01-01

    Ash fertilization of forests returns nutrients to forest ecosystems and has a positive effect on soil pH.but it also may elevate Cd concentrations of forest biota.Cadmium concentrations of some forest insects(Formica ants.carabids and Coleopteran larvac from decaying wood)were investigated in southern Finland where two plots were fertilized with wood ash,while two other plots represented anfertilized control plots.In ants,mean Cd concentration was 3.6±1.4 mg/kg.with nest workers having significantly higher concen-trations than workers trapped in pitfall traps.Concentrations at fertilized and unfertilized plots were similar.In carabid beetles,the average Cd concentration of Carabus glabratus was 0.44±0.36 mg/kg.with no significant difference between control plots and fertilized plots.In another carabid beetle,Pterostichus niger,mean Cd concentration was higher at fertilized plots compared to control plots.We conclude that the variation of Cd concentra-tions in the insects studied is more efficiently controlled by species-specific differences than fertilization history of the forest floor.

  15. Family systems and fertility

    NARCIS (Netherlands)

    Moenkediek, Bastian

    2016-01-01

    This thesis studies the role of regional family organization principles, so called family systems, for explaining fertility behaviours in different parts of Europe. Studying family systems and its impact on fertility is important, because many aspects of societal life, such as the organization of we

  16. Human rights to in vitro fertilization.

    Science.gov (United States)

    Zegers-Hochschild, Fernando; Dickens, Bernard M; Dughman-Manzur, Sandra

    2013-10-01

    The Inter-American Court of Human Rights (the Court) has ruled that the Supreme Court of Costa Rica's judgment in 2000 prohibiting in vitro fertilization (IVF) violated the human right to private and family life, the human right to found and raise a family, and the human right to non-discrimination on grounds of disability, financial means, or gender. The Court's conclusions of violations contrary to the American Convention on Human Rights followed from its ruling that, under the Convention, in vitro embryos are not "persons" and do not possess a right to life. Accordingly, the prohibition of IVF to protect embryos constituted a disproportionate and unjustifiable denial of infertile individuals' human rights. The Court distinguished fertilization from conception, since conception-unlike fertilization-depends on an embryo's implantation in a woman's body. Under human rights law, legal protection of an embryo "from conception" is inapplicable between its creation by fertilization and completion of its implantation in utero. © 2013.

  17. [Socioeconomic variables and fertility].

    Science.gov (United States)

    Arguello, O

    1980-08-01

    While making comparative analyses of data collected by the World Fertility Survey regarding Latin America, a group of investigators of CELADE (Centro Latinoamericano de Demografia) realized that the selection of economic variables for the study of fertility had serious limitations. Such limitations did not allow the elaboration of a theory which took into account the complicated process of fertility, in all its socioeconomic, cultural, and psychological manifestations. Thus, this paper intends to lay the theoretical basis for the selection of all relevant variables, distinguishing, for example, the average fertility of women according to area of residence, place of early socialization, migrant status, social status, occupation of husband, level of instruction, occupation, and all changes in occupational activities of women in fertile age.

  18. Endogenous fertility, mortality and growth.

    Science.gov (United States)

    Blackburn, K; Cipriani, G P

    1998-01-01

    This paper presents a model that illustrates the joint determination of population and development. "Economic and demographic outcomes are determined jointly in a choice-theoretic model of fertility, mortality and capital accumulation.... In addition to choosing savings and births, parents may reduce (infant) deaths by incurring expenditures on health-care which is also provided by the government. A generalised production technology accounts for long-run endogenous growth with short-run transitional dynamics. The analysis yields testable time series and cross-section implications which accord with the empirical evidence on the relationship between demography and development."

  19. Produtividade do cafeeiro e atributos de fertilidade de latossolo sob influência de adensamento da lavoura e manejo da calagem Coffee yield and fertility attributes of a latosol under influence of population density and liming management

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Silva

    2004-10-01

    Full Text Available Com este estudo, teve-se por objetivo avaliar os efeitos de densidades de plantio e de manejo da calagem sobre os atributos de fertilidade de Latossolo e sobre o estado nutricional e produtividade do cafeeiro (Coffea arabica L.. O estudo foi conduzido de fevereiro de 2000 a junho de 2003 na Fazenda Experimental da EPAMIG, em São Sebastião do Paraíso (MG. Os tratamentos testados consistiram da combinação de duas densidades populacionais (2.857 e 10.000 plantas ha-1 com três métodos de manejo de calagem (sem aplicação de calcário; calagem superficial e incorporação de calcário de 0 a 20 cm, além de um tratamento com aplicação de calcário (0 a 20 cm e gesso. O solo foi amostrado nas camadas de 0 a 10, 10 a 20 e 20 a 40 cm de profundidade, em quatro épocas de amostragem, sendo realizadas as seguintes determinações analíticas: pH, Ca e Mg trocáveis, P (Mehlich-1, sulfato, nitrato e amônio, além da saturação por bases. Os métodos de manejo da calagem reduziram a acidez na camada de solo de 0 a 10 cm; contudo, somente na quarta amostragem foi verificada movimentação no perfil de solo do calcário aplicado em superfície. Os atributos de fertilidade do Latossolo não foram influenciados pelos sistemas de plantio de cafeeiro. O adensamento da lavoura resultou em um acréscimo médio na produtividade de cafeeiro de 14 e 33 sacas ha-1, respectivamente, para a 1ª e 2ª colheitas.The objective of this work was to evaluate the effects of coffee population density and liming management practices on the fertility attributes of a Latosol, and in the nutritional status and yield of coffee (Coffea arabica L.. The experiment was carried out from February 2000 to June 2003 in the Experimental Farm of Epamig (São Sebastião do Paraíso, MG. The treatments tested consisted of the combination of two coffee population densities (2,857 and 10,000 plants ha-1 with three methods of liming management (without lime; lime incorporation at 0 to

  20. Fertility and the environment in a natural resource dependent economy: Evidence from Petén, Guatemala

    Directory of Open Access Journals (Sweden)

    Curtis, Siân L.

    2004-07-01

    Full Text Available This paper examines potential relations between factors related to fertility and the access to and use of natural resources in Petén, Guatemala. The Petén forms the heart of the Selva Maya, the largest lowland humid forest in Mesoamerica. The rapid in-migration of subsistence maize farmers has converted much of the Petén's forests to agricultural fields. Population dynamics have been transformed in that virtually all farm families have arrived since the 1970s and that total fertility rates exceed the national rural mean. Continued migration, exceptionally high fertility, a youthful population, and a large consumer to producer ratio are hypothesized to be related to the dramatic land cover dynamics shaping the landscape of the Petén. An emerging body of literature suggests that environmental factors can affect fertility decision-making and behaviors, especially in natural resource dependent economies like that of the Petén. This paper examines these relationships using data from the 1998/99 Demographic Health Survey in Guatemala. Data on natural resource access and utilization were collected as part of an environment module, in addition to demographic and health information. This dataset, the first ever environmental module of the Demographic Health Survey, provides a unique opportunity to examine possible relationships between fertility and the environment in a tropical agricultural frontier.

  1. Fertility and the environment in a natural resource dependent economy: Evidence from Petén, Guatemala

    Directory of Open Access Journals (Sweden)

    Elizabeth G. Sutherland

    2004-01-01

    Full Text Available This paper examines potential relations between factors related to fertility and the access to and use of natural resources in Petén, Guatemala. The Petén forms the heart of the Selva Maya, the largest lowland humid forest in Mesoamerica. The rapid in-migration of subsistence maize farmers has converted much of the Petén´s forests to agricultural fields. Population dynamics have been transformed in that virtually all farm families have arrived since the 1970s and that total fertility rates exceed the national rural mean. Continued migration, exceptionally high fertility, a youthful population, and a large consumer to producer ratio are hypothesized to be related to the dramatic land cover dynamics shaping the landscape of the Petén. An emerging body of literature suggests that environmental factors can affect fertility decision-making and behaviors, especially in natural resource dependent economies like that of the Petén. This paper examines these relationships using data from the 1998/99 Demographic Health Survey in Guatemala. Data on natural resource access and utilization were collected as part of an environment module, in addition to demographic and health information. This dataset, the first ever environmental module of the Demographic Health Survey, provides a unique opportunity to examine possible relationships between fertility and the environment in a tropical agricultural frontier.

  2. Quantitative Trait Loci for Fertility Traits in Finnish Ayrshire Cattle

    DEFF Research Database (Denmark)

    Schulman, Nina F; Sahana, Goutam; Lund, Mogens S

    2008-01-01

    A whole genome scan was carried out to detect quantitative trait loci (QTL) for fertility traits in Finnish Ayrshire cattle. The mapping population consisted of 12 bulls and 493 sons. Estimated breeding values for days open, fertility treatments, maternal calf mortality and paternal non-return rate...... if these effects were due to a pleiotropic QTL affecting fertility and milk yield traits or to linked QTL causing the effects. This distinction could only be made with confidence on BTA1 where a QTL affecting milk yield is linked to a pleiotropic QTL affecting days open and fertility treatments...

  3. China's fertility drop lowers world growth rate.

    Science.gov (United States)

    Haub, C

    1993-06-01

    China practices a stringent and compulsory program of family planning and population control. This approach has, however, served to increase the number of domestic IUD insertions and sterilizations. Contraceptive prevalence has reached 83% and total fertility (TFR) is estimated to be 1.9. This Chinese accomplishment has helped reduce TFR for all East Asia to 1.8, which is lower than that for northern Europe, and bring the world population growth rate down from the 1992 level of 1.68% to 1.63%. This latter rate is reported in the 1993 Population Reference Bureau's (PRB) World Population Data Sheet and is the lowest world population growth rate since PRB's first annual edition in 1962. Despite these reductions, world population still grows by 90 million annually. No one can say for sure whether or not observed fertility decline in China is permanent. China's birth rate rose twice in the 1980s and it could certainly rebound once again. A popular backlash to population policy or a relaxing of policy due to international pressure to reduce the level of compulsion in the program are 2 factors which might increase overall fertility and population growth. Fertility is also declining in subSaharan Africa, but not universally. Birth rates are rapidly declining in eastern Europe and the former USSR as economic conditions and outlooks pale. The populations of Estonia, Latvia, Ukraine, and possible Russia are even declining, while only mixed data are available from Yugoslavia. New statistical publications reflect changing borders. Finally, while Slovakia is the only country added to this year's sheet, Eritrea and the Channel Islands will likely be included in next year's.

  4. On Diffused Pollution Effect of Chemical Fertilizers in Chongqing Municipality

    Institute of Scientific and Technical Information of China (English)

    Limeng; GU; Lianchao; YU; Qian; BI

    2015-01-01

    Improper use of chemical fertilizers is an essential reason for diffused pollution of agriculture. Therefore,finding out influence factors of farmers in application of chemical fertilizers will play a significant role in controlling the diffused pollution of agriculture. Through field survey,a total of 340 samples in 4 counties of Chongqing Municipality were obtained. On the basis of these samples,an empirical study was carried out. The study results indicate that farmers’ application of chemical fertilizers is negatively correlated with farmers’ age,education level,male labor proportion,and soil fertility,while the annual family income,agricultural production population proportion,commodity trading characteristics,and scientific fertilizer application ability fail to pass the significance test. These results will provide reference for proper application of chemical fertilizers and controlling diffused pollution.

  5. Evaluate Potential Means of Rebuilding Sturgeon Populations in the Snake River between Lower Granite and Hells Canyon Dams, 2000 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Everett, Scott R.; Tuell, Michael A. (Nez Perce Tribe, Department of Fishereis Resource Management, Lapwai, ID)

    2003-03-01

    The specific research goal of this project is to identify means to restore and rebuild the Snake River white sturgeon (Acipenser transmontanus) population to support a sustainable annual subsistence harvest equivalent to 5 kg/ha/yr (CBFWA 1997). Based on data collected, a white sturgeon adaptive management plan will be developed. This 2000 annual report covers the fourth year of sampling of this multi-year study. In 2000 white sturgeon were captured, marked, and population data were collected in the Snake and Salmon rivers. The Snake River was sampled between Lower Granite Dam (rkm 174) and the mouth of the Salmon River (rkm 303), and the Salmon River was sampled from its mouth upstream to Hammer Creek (rkm 84). A total of 53,277 hours of setline effort and 630 hours of hook-and-line effort was employed in 2000. A total of 538 white sturgeon were captured and tagged in the Snake River and 25 in the Salmon River. Since 1997, 32.8 percent of the tagged white sturgeon have been recaptured. In the Snake River, white sturgeon ranged in total length from 48 cm to 271 cm and averaged 107 cm. In the Salmon River, white sturgeon ranged in total length from 103 cm to 227 cm and averaged 163 cm. Using the Jolly-Seber open population estimator, the abundance of white sturgeon <60 cm, between Lower Granite Dam and the mouth of the Salmon River, was estimated at 2,725 fish, with a 95% confidence interval of 1,668-5,783. A total of 10 white sturgeon were fitted with radio-tags. The movement of these fish ranged from 54.7 km (34 miles) downstream to 78.8 km (49 miles) upstream; however, 43.6 percent of the detected movement was less than 0.8 km (0.5 mile). Both radio-tagged fish and recaptured white sturgeon in Lower Granite Reservoir appear to move more than fish in the free-flowing segment of the Snake River. No seasonal movement pattern was detected, and no movement pattern was detected for different size fish. Differences were detected in the length frequency distributions of

  6. Fertility desires among men and women living with HIV/AIDS in Nairobi slums: a mixed methods study.

    Directory of Open Access Journals (Sweden)

    Eliud Wekesa

    Full Text Available Fertility desires require new understanding in a context of expanding access to antiretroviral therapy for people living with HIV/AIDS in Sub-Saharan Africa. This paper studies the fertility desires and their rationales, of slum-dwelling Kenyan men and women living with HIV/AIDS who know their serostatus, but have different antiretroviral therapy treatment statuses. It addresses two research questions: How do people living with HIV/AIDS consider their future fertility? What factors contribute to an explanation of fertility desires among people living with HIV/AIDS.A mixed methods study (survey [n = 513] and in-depth interviews [n = 41] with adults living with HIV/AIDS living in Nairobi slums was conducted in 2010. Regression analyses assess independent relationships between fertility desires and socio-demographic factors. Analyses of in-depth interviews are used to interpret the statistical analyses of fertility desires.Our analyses show that fertility desires are complex and ambivalent, reflecting tensions between familial and societal pressures to have children versus pressures for HIV (re-infection prevention. More than a third (34% of men and women living with HIV expressed future fertility desires; however, this is significantly lower than in the general population. Factors independently associated with desiring a child among people living with HIV/AIDS were age, sex, number of surviving children, social support and household wealth of the respondent.Increasing access to ART is changing the context of future childbearing for people living with HIV/AIDS. Prevailing values mean that, for many people living with HIV/AIDS, having children is seen as necessary for a "normal" and healthy adult life. However, the social rewards of childbearing conflict with moral imperatives of HIV prevention, presenting dilemmas about the "proper" reproductive behaviour of people living with HIV/AIDS. The health policy and service delivery implications of

  7. Fertility desires among men and women living with HIV/AIDS in Nairobi slums: a mixed methods study.

    Science.gov (United States)

    Wekesa, Eliud; Coast, Ernestina

    2014-01-01

    Fertility desires require new understanding in a context of expanding access to antiretroviral therapy for people living with HIV/AIDS in Sub-Saharan Africa. This paper studies the fertility desires and their rationales, of slum-dwelling Kenyan men and women living with HIV/AIDS who know their serostatus, but have different antiretroviral therapy treatment statuses. It addresses two research questions: How do people living with HIV/AIDS consider their future fertility? What factors contribute to an explanation of fertility desires among people living with HIV/AIDS. A mixed methods study (survey [n = 513] and in-depth interviews [n = 41]) with adults living with HIV/AIDS living in Nairobi slums was conducted in 2010. Regression analyses assess independent relationships between fertility desires and socio-demographic factors. Analyses of in-depth interviews are used to interpret the statistical analyses of fertility desires. Our analyses show that fertility desires are complex and ambivalent, reflecting tensions between familial and societal pressures to have children versus pressures for HIV (re-)infection prevention. More than a third (34%) of men and women living with HIV expressed future fertility desires; however, this is significantly lower than in the general population. Factors independently associated with desiring a child among people living with HIV/AIDS were age, sex, number of surviving children, social support and household wealth of the respondent. Increasing access to ART is changing the context of future childbearing for people living with HIV/AIDS. Prevailing values mean that, for many people living with HIV/AIDS, having children is seen as necessary for a "normal" and healthy adult life. However, the social rewards of childbearing conflict with moral imperatives of HIV prevention, presenting dilemmas about the "proper" reproductive behaviour of people living with HIV/AIDS. The health policy and service delivery implications of these

  8. Fertility Preservation for Cancer Patients: A Review

    Directory of Open Access Journals (Sweden)

    Tosin Ajala

    2010-01-01

    Full Text Available Infertility can arise as a consequence of treatment of oncological conditions. The parallel and continued improvement in both the management of oncology and fertility cases in recent times has brought to the fore-front the potential for fertility preservation in patients being treated for cancer. Oncologists must be aware of situations where their treatment will affect fertility in patients who are being treated for cancer and they must also be aware of the pathways available for procedures such as cryopreservation of gametes and/or embryos. Improved cancer care associated with increased cure rates and long term survival, coupled with advances in fertility treatment means that it is now imperative that fertility preservation is considered as part of the care offered to these patients. This can only be approached within a multidisciplinary setting. There are obvious challenges that still remain to be resolved, especially in the area of fertility preservation in prepubertal patients. These include ethical issues, such as valid consent and research in the area of tissue retrieval, cryopreservation, and transplantation.

  9. Balanced Fertilization and the Effect of Fertiliztion on Water Use Efficiency of Upland Winter Wheat in Western Henan,China

    Institute of Scientific and Technical Information of China (English)

    LIGUIBAO; LEIQUANKUI; 等

    1998-01-01

    A study on balanced fertilization was conducted by means of long-term field experiments,and a conve-nient table for balanced fertilization was compiled.The experimental results about the effect of fertilization on water use efficiency of upland wheat showed that the input of inorganic fertilizer should be reduced in dry years.

  10. Optimizing Natural Fertility

    Science.gov (United States)

    ... heavy alcohol consumption (> 2 drinks per day), heavy caffeine consumption, and the use of recreational drugs such as marijuana have all been associated with reduced fertility. Therefore, women (and ... alcohol and caffeine use, and avoid smoking and all recreational drugs ...

  11. Commercial Nitrogen Fertilizer Purchased

    Data.gov (United States)

    U.S. Environmental Protection Agency — Amounts of fertilizer nitrogen (N) purchased by states in individual years 2003, 2005, 2007, 2009 and 2011, and the % change in average amounts purchased per year...

  12. Chapter VII. Predicting Fertility

    Science.gov (United States)

    Section 2. Visual and Microscopic Approaches for Differentiating Unfertilized Germinal Discs and Early dead Embryos from Pre-Incubated Blastoderms Section 3. Predicting the Duration of fertility by Counting Sperm in the Outer Perivitelline Layer of Laid Eggs...

  13. Cancer and fertility preservation

    DEFF Research Database (Denmark)

    Lambertini, Matteo; Del Mastro, Lucia; Pescio, Maria C

    2016-01-01

    cryopreservation and embryo/oocyte cryopreservation are standard strategies for fertility preservations in male and female patients, respectively; other strategies (e.g. pharmacological protection of the gonads and gonadal tissue cryopreservation) are considered experimental techniques. However, since then, new......In the last years, thanks to the improvement in the prognosis of cancer patients, a growing attention has been given to the fertility issues. International guidelines on fertility preservation in cancer patients recommend that physicians discuss, as early as possible, with all patients...... of reproductive age their risk of infertility from the disease and/or treatment and their interest in having children after cancer, and help with informed fertility preservation decisions. As recommended by the American Society of Clinical Oncology and the European Society for Medical Oncology, sperm...

  14. Commercial Phosporus Fertilizer Purchased

    Data.gov (United States)

    U.S. Environmental Protection Agency — Amounts of fertilizer P2O5 purchased by states in individual years 2003, 2005, 2007, 2009 and 2011, and the % change in average amounts purchased per year from...

  15. Alternative approaches to ovarian stimulation for in vitro fertilization

    NARCIS (Netherlands)

    D. de Jong (Diederick)

    2003-01-01

    markdownabstract__Abstract__ In vitro fertilization (IVF), literally meaningfertilization in glass’, is characterized by co-culture of aspired oocytes with spermatozoa and subsequent transfer of the embryo(s) into the uterine cavity. The original indication for this treatment was subfertility res

  16. Alternative approaches to ovarian stimulation for in vitro fertilization

    NARCIS (Netherlands)

    D. de Jong (Diederick)

    2003-01-01

    markdownabstract__Abstract__ In vitro fertilization (IVF), literally meaningfertilization in glass’, is characterized by co-culture of aspired oocytes with spermatozoa and subsequent transfer of the embryo(s) into the uterine cavity. The original indication for this treatment was

  17. THE DYNAMICS OF FERTILITY IN C-K MODEL WITH ENDOGENOUS FERTILITY

    Institute of Scientific and Technical Information of China (English)

    蔡东汉

    2002-01-01

    Based on the Cass-Koopmans Model with endogenous fertility given in the paper [1-4], the fertility dynamics is discussed in this paper. It is proved that the first quadrant of the k,c plane is separated into two parts by a increasingly differentiable curve.The fertility increases with time on the upper half and decreases with time on the lower half. The fertility decreases along one arm of the economic growth path on which the per capita capital and per consumption increase and increases along the other arm of the economic growth path on which the per capita capital and per person consumption decrease under the condition 0 <θ≤α. This confirms the empirical finds that negative relationship between the economic growth and population growth.

  18. Sexuality and fertility in women with Addison's disease.

    Science.gov (United States)

    Erichsen, Martina M; Husebye, Eystein S; Michelsen, Trond M; Dahl, Alv A; Løvås, Kristian

    2010-09-01

    Females with primary adrenal insufficiency (Addison's disease) have reduced levels of circulating androgens, which are allegedly important for sexual functioning. The aim was to determine peripheral androgen status, sexual functioning, and birth rates in Addison's disease females. In a postal survey, all 269 females in the Norwegian Addison's registry were invited to complete the Sexual Activity Questionnaire (SAQ) and registration of childbirths. Blood samples were analyzed for 5alpha-androstane-3alpha,17beta-diol-3-glucuronide (3alpha-Diol-G) and compared with blood donor levels. The SAQ scores were compared with 740 age-matched controls from the general population and 234 women subjected to risk-reducing salpingo-oophorectomy. Fertility was estimated as standardized incidence ratio for birth; the expected number of births was estimated from population statistics. The SAQ was completed by 174 (65%) of the Addison's patients. Those not taking DHEA had significantly lower 3alpha-Diol-G levels than blood donors (mean, 0.53 vs. 2.2 ng/ml; P Addison's disease females were equally sexually active as the controls, but they reported significantly higher pleasure and less discomfort. They reported lower pleasure but less discomfort than the risk-reducing salpingo-oophorectomy women. The fertility was significantly reduced in females with Addison's disease; 54 children were born to mothers with established diagnosis (87.5 expected), yielding a standardized incidence ratio for birth of 0.69 (confidence interval, 0.52-0.86). Despite androgen depletion, females with Addison's disease do not report impaired sexuality. The fertility is reduced after the diagnosis is made; the reasons for this remain unknown.

  19. Evaluate Potenial Means of Rebuilding Sturgeon Populations in the Snake River between Lower Granite and Hells Canyon Dams, 2002 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Everett, Scott R.; Tuell, Michael A.; Hesse, Jay A. (Nez Perce Tribe, Department of Fisheries Management, Lapwai, ID)

    2004-02-01

    The specific research goal of this project is to identify means to restore and rebuild the Snake River white sturgeon (Acipenser transmontanus) population to support a sustainable annual subsistence harvest equivalent to 5 kg/ha/yr (CBFWA 1997). Based on data collected, a white sturgeon adaptive management plan will be developed. This report presents a summary of results from the 1997-2002 Phase II data collection and represents the end of phase II. From 1997 to 2001 white sturgeon were captured, marked, and population data were collected in the Snake and Salmon. A total of 1,785 white sturgeon were captured and tagged in the Snake River and 77 in the Salmon River. Since 1997, 25.8 percent of the tagged white sturgeon have been recaptured. Relative density of white sturgeon was highest in the free-flowing segment of the Snake River, with reduced densities of fish in Lower Granite Reservoir, and low densities the Salmon River. Differences were detected in the length frequency distributions of white sturgeon in Lower Granite Reservoir, the free-flowing Snake River and the Salmon River (Chi-Square test, P<0.05). The proportion of white sturgeon greater than 92 cm (total length) in the free-flowing Snake River has shown an increase of 30 percent since the 1970's. Using the Jolly-Seber model, the abundance of white sturgeon <60 cm, between Lower Granite Dam and the mouth of the Salmon River, was estimated at 2,483 fish, with a 95% confidence interval of 1,208-7,477. Total annual mortality rate was estimated to be 0.14 (95% confidence interval of 0.12 to 0.17). A total of 35 white sturgeon were fitted with radio-tags during 1999-2002. The movement of these fish ranged from 53 km (33 miles) downstream to 77 km (48 miles) upstream; however, 38.8 percent of the detected movement was less than 0.8 km (0.5 mile). Both radio-tagged fish and recaptured white sturgeon in Lower Granite Reservoir appear to move more than fish in the free-flowing segment of the Snake River. No

  20. Evaluate Potential Means of Rebuilding Sturgeon Populations in the Snake River between Lower Granite and Hells Canyon Dams, 1999 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Tuell, Michael A.; Everett, Scott R. (Nez Perce Tribe, Department of Fisheries Resource Management, Lapwai, ID)

    2003-03-01

    The specific research goal of this project is to identify means to restore and rebuild the Snake River white sturgeon (Acipenser transmontanus) population to support a sustainable annual subsistence harvest equivalent to 5 kg/ha/yr (CBFWA 1997). Based on data collected, a white sturgeon adaptive management plan will be developed. This 1999 annual report covers the third year of sampling of this multi-year study. In 1999 white sturgeon were captured, marked and population data were collected in the Snake and Salmon rivers. A total of 33,943 hours of setline effort and 2,112 hours of hook-and-line effort was employed in 1999. A total of 289 white sturgeon were captured and tagged in the Snake River and 29 in the Salmon River. Since 1997, 11.1 percent of the tagged white sturgeon have been recaptured. In the Snake River, white sturgeon ranged in total length from 27 cm to 261 cm and averaged 110 cm. In the Salmon River, white sturgeon ranged in total length from 98 cm to 244 cm and averaged 183.5 cm. Using the Jolly-Seber model, the abundance of white sturgeon < 60 cm, between Lower Granite Dam and the mouth of the Salmon River, was estimated at 1,823 fish, with a 95% confidence interval of 1,052-4,221. A total of 15 white sturgeon were fitted with radio-tags. The movement of these fish ranged from 6.4 km (4 miles) downstream to 13.7 km (8.5 miles) upstream; however, 83.6 percent of the detected movement was less than 0.8 kilometers (0.5 miles). Both radio-tagged fish and recaptured white sturgeon in Lower Granite Reservoir appear to move more than fish in the free-flowing segment of the Snake River. No seasonal movement pattern was detected, and no movement pattern was detected for different size fish. Differences were detected in the length frequency distributions of white sturgeon in Lower Granite Reservoir and the free-flowing Snake River (Chi-Square test, P < 0.05). The proportion of white sturgeon greater than 92 cm (total length) in the free-flowing Snake River

  1. Evaluate Potential Means of Rebuilding Sturgeon Populations in the Snake River between Lower Granite and Hells Canyon Dams, 2001 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Everett, Scott R.; Tuell, Michael A. (Nez Perce Tribe, Department of Fisheries Resource Management, Lapwai, ID)

    2003-03-01

    The specific research goal of this project is to identify means to restore and rebuild the Snake River white sturgeon (Acipenser transmontanus) population to support a sustainable annual subsistence harvest equivalent to 5 kg/ha/yr (CBFWA 1997). Based on data collected, a white sturgeon adaptive management plan will be developed. This 2001 annual report covers the fifth year of sampling of this multi-year study. In 2001 white sturgeon were captured, marked, and population data were collected in the Snake and Salmon rivers. The Snake River was sampled between Lower Granite Dam (rkm 174) and the mouth of the Salmon River (rkm 303), and the Salmon River was sampled from its mouth upstream to Hammer Creek (rkm 84). A total of 45,907 hours of setline effort and 186 hours of hook-and-line effort was employed in 2001. A total of 390 white sturgeon were captured and tagged in the Snake River and 12 in the Salmon River. Since 1997, 36.1 percent of the tagged white sturgeon have been recaptured. In the Snake River, white sturgeon ranged in total length from 42 cm to 307 cm and averaged 107 cm. In the Salmon River, white sturgeon ranged in total length from 66 cm to 235 cm and averaged 160 cm. Using the Jolly-Seber model, the abundance of white sturgeon <60 cm, between Lower Granite Dam and the mouth of the Salmon River, was estimated at 2,483 fish, with a 95% confidence interval of 1,208-7,477. An additional 10 white sturgeon were fitted with radio-tags during 2001. The locations of 17 radio-tagged white sturgeon were monitored in 2001. The movement of these fish ranged from 38.6 km (24 miles) downstream to 54.7 km (34 miles) upstream; however, 62.6 percent of the detected movement was less than 0.8 km (0.5 mile). Both radio-tagged fish and recaptured white sturgeon in Lower Granite Reservoir appear to move more than fish in the free-flowing segment of the Snake River. No seasonal movement pattern was detected, and no movement pattern was detected for different size fish

  2. [The Northeast: fertility and recent dynamics of the labor force].

    Science.gov (United States)

    De Oliveira, L A

    1985-01-01

    Data from the 1970 and 1980 censuses of Brazil are analyzed to examine the economic growth of the Notheast, changes in the region's population dynamics, and changes in fertility. Consideration is given to the segmentation of the urban labor market, the income of the economically active population, children in the labor force, female education versus fertility, and family income versus female participation in the work force.

  3. 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.

  4. Factors Affecting Fertility – New Evidence from Malaysia

    Directory of Open Access Journals (Sweden)

    Awad Atif

    2017-06-01

    Full Text Available This research paper investigates long and short term determinants of fertility rates in Malaysia based on basic macroeconomic variables for the period 1980-2014 using Auto Regressive Distributed Lag (ARDL method. The study reveals that over a long term period, all the selected variables (GDP, infant mortality rate, females’ education and employment have had significant and negative impact on total fertility rates. Whilst during the short term period, only the infant mortality rate has had a positive impact. Since population growth is partly determined by fertility rates, efforts to increase population in Malaysia should consider factors that affect those rates.

  5. Education’s impact on fertility: The case of King Saud University Women, Riyadh

    Directory of Open Access Journals (Sweden)

    Rshood M. Khraif

    2017-06-01

    Conclusions: Thus, the improving educational levels at current pace shall bring down fertility remarkably warranting attention, policy measures and population programs to retain it above the replacement level.

  6. Soil seed-bank germination patterns in natural pastures under different mineral fertilizer treatments

    Directory of Open Access Journals (Sweden)

    Anna Iannucci

    2014-11-01

    Full Text Available Degraded native grasslands in Mediterranean areas can be improved by encouraging seedling regeneration from soil seed banks using chemical fertilization. The effect of mineral fertilizers on soil seed banks was studied in natural pastures at two locations in southern Italy: Carpino and Rignano Garganico. The aim was to determine if nitrogen (N, phosphorus (P and combined nitrogen and phosphorus (NP fertilization can promote increased soil seed density. The seed-bank size and composition were analysed over two growth cycles (2004-2006 at two periods of the year: at the early summer and at the early autumn. The plant species were classified into three functional groups: grasses, legumes and other species (all other dicots. A two-pool model (ephemeral and base pools derived from the germination patterns was developed to quantify the dynamics of the germinated seed populations. The mean total seed number in the seed bank ranged from 2,915 to 4,782 seed m-2 with higher values in early summer than in early autumn. Mineral fertilizer applications increased the seed-bank size (by 27%, 23% and 46%, for N, P and NP, respectively and modified the composition in both localities. The three plant functional groups showed different potentials for ephemeral and persistent seed-bank production; however, within each plant group, the proportion between the ephemeral and base pool fractions did not change with fertilizer application. These data show that mineral fertilization can have positive effects on the seed-bank size of ungrazed natural pastures, and can be used to improve degraded Mediterranean pastures.

  7. Fertility attitudes and the fear of death.

    Science.gov (United States)

    Hoelter, J W; Whitlock, J L; Epley, R J

    1979-12-01

    An attempt to test empirically the general proposition that fear of death is related to certain attitudes about fertility, particularly expected number of children. Analysis of data collected from 355 undergraduates at a midwestern U.S. university showed this proposition to be generally supported and dependent, in part, on respondents' sex. Those who are more fearful of death tend to perceive procreation as a means for others to reduce fear of death, and also tend to expect having a greater number of children than those whose fear is less. Although the interrelationships of the variables appears somewhat complex, they provide an empirical reference for further research linking mortality to fertility.

  8. Phenotypes, genome wide markers and structured genetic populations; a means to understand economically important traits in beta vulgaris and to inform the process of germplasm enhancement

    Science.gov (United States)

    Although hybrid seed systems in beet have been widely adopted due to profitability and productivity, the population remains the operational unit of beet improvement and thus characterizing populations in terms of markers and phenotypes is critical for novel trait discovery and eventual deployment of...

  9. The existence of different Fin Whale, Balaenoptera physalus, populations in South Atlantic waters. A preliminary study by means of morphological characters

    NARCIS (Netherlands)

    Beek, van J.G.; Utrecht, van W.L.

    1984-01-01

    The southern hemisphere has been divided into six Areas for baleen whale management purposes. It was assumed that of the different baleen whale species one population lives in each Area. However, evidence exists which suggests that different Fin Whale populations intermingle on the feeding grounds o

  10. Fertility assurance through extrapair fertilization, and male parental effort.

    Science.gov (United States)

    Fishman, Michael A; Stone, Lewi

    2002-07-01

    Extrapair paternity (EPP) has been observed in many formally monogamous species. Male pursuit of extrapair fertilizations (EPF) is explained by the advantages of having offspring that receive essential paternal care from other males. Because females are capable of exercising a degree of control over the post-copulatory sperm competition, EPP's persistence indicates that females benefit from EPF. Thus, EPP involves cooperation between mated females and extrapair males. On the other hand, mated males exhibit a spectrum of anti-cuckolding strategies. Hence, extrapair attributes of diverse species and populations reported in the literature are particular solutions of evolutionary games involving gender-specific cuckolding/anti-cuckolding strategies. Here we use game theoretical methods to study the effect of male paternal effort conserving strategies in situations where females seek EPF for reasons of genetic compatibility and/or in pursuit of genetic diversity for their offspring. Our results indicate that in these circumstances pursuit of EPF is the only evolutionary stable female strategy. Males, on the other hand, have two, mutually exclusive, evolutionary stable strategies: males that restrict parental care regardless of their mate's fidelity, and males that never restrict parental care. That is, when females seek EPF for reasons of fertility assurance and/or genetic diversity, the conditional male strategy--therein the male's parental efforts are based on his certainty of paternity--loses in competition with the unconditional strategies.

  11. Sotho fertility symbolism.

    Science.gov (United States)

    Murray, C

    1980-01-01

    This paper deals with the traditional beliefs and mythical folklore of the Sotho-Tswana ethnic tribes of South Africa. Their ritual practices are predominantly concerned with the weather, the vicissitudes of the seasonal cycle, and, especially the rain-making powers of certain individuals. It is well known that rain, in all civilizations, is a symbol of fertility. Thus, adolescent girls and young women, as mediators of the association between water and fertility, can be relied upon to bring the clouds and torrential downpours. The characteristic Sesotho explanation that babies come from the river is clearly an allusion to the water of the womb, and the river is generally recognized as a methaphor of the womb. Also, the onset of menarche involves rituals having to do with the drawing and pouring of water, another clear allusion to the beginning of fertility.

  12. The cultural evolution of fertility decline

    Science.gov (United States)

    Colleran, Heidi

    2016-01-01

    Cultural evolutionists have long been interested in the problem of why fertility declines as populations develop. By outlining plausible mechanistic links between individual decision-making, information flow in populations and competition between groups, models of cultural evolution offer a novel and powerful approach for integrating multiple levels of explanation of fertility transitions. However, only a modest number of models have been published. Their assumptions often differ from those in other evolutionary approaches to social behaviour, but their empirical predictions are often similar. Here I offer the first overview of cultural evolutionary research on demographic transition, critically compare it with approaches taken by other evolutionary researchers, identify gaps and overlaps, and highlight parallel debates in demography. I suggest that researchers divide their labour between three distinct phases of fertility decline—the origin, spread and maintenance of low fertility—each of which may be driven by different causal processes, at different scales, requiring different theoretical and empirical tools. A comparative, multi-level and mechanistic framework is essential for elucidating both the evolved aspects of our psychology that govern reproductive decision-making, and the social, ecological and cultural contingencies that precipitate and sustain fertility decline. PMID:27022079

  13. Fertility in Namibia. Changes in fertility levels in North-Central Namibia 1960-2001, including an assessment of the impact of HIV

    Directory of Open Access Journals (Sweden)

    Riikka Shemeikka

    2006-01-01

    Full Text Available The aim of this study was to estimate the development of fertility in North-Central Namibia, former Ovamboland, from 1960 to 2001. Special attention was given to the onset of fertility decline and to the impact of the HIV epidemic on fertility. An additional aim was to introduce parish registers as a source of data for fertility research in Africa.  Data used consisted of parish registers from Evangelical Lutheran congregations, the 1991 and 2001 Population and Housing Censuses, the 1992 and 2000 Namibia Demographic and Health Surveys, and the HIV sentinel surveillances of 1992-2004. Both period and cohort fertility were analysed. The P/F ratio method was used when analysing census data. The impact of HIV infection on fertility was estimated indirectly by comparing the fertility histories of women who died at an age of less than 50 years with the fertility of other women. The impact of the HIV epidemic on fertility was assessed both among infected women and in the general populationFertility in the study population began to decline in 1980. The decline was rapid during the 1980s, levelled off in the early 1990s at the end of war of independence and then continued to decline until the end of the study period. According to parish registers, total fertility was 6.4 in the 1960s and 6.5 in the 1970s, and declined to 5.1 in the 1980s and 4.2 in the 1990s. Adjustment of these total fertility rates to correspond to levels of fertility based on data from the 1991 and 2001 censuses resulted in total fertility declining from 7.6 in 1960-79 to 6.0 in 1980-89, and to 4.9 in 1990-99. The decline was associated with increased age at first marriage, declining marital fertility and increasing premarital fertility. Fertility among adolescents increased, whereas the fertility of women in all other age groups declined.  During the 1980s, the war of independence contributed to declining fertility through spousal separation and delayed marriages. Contraception

  14. Fertility in China: An uncertain future

    OpenAIRE

    2015-01-01

    As one of the world’s two population ‘billionaires’, the future of China’s population is truly of global significance. With its very low fertility and a rapidly ageing population, it might appear that the country’s famous (or notorious) family planning restrictions are somewhat anachronistic. Here, we explore the process of reform seen over the past three decades and, most recently, in late 2013. We suggest that the popular notion that the family planning restrictions are acting as a pressure...

  15. Non-Invasive Genetic Mark-Recapture as a Means to Study Population Sizes and Marking Behaviour of the Elusive Eurasian Otter (Lutra lutra).

    Science.gov (United States)

    Lampa, Simone; Mihoub, Jean-Baptiste; Gruber, Bernd; Klenke, Reinhard; Henle, Klaus

    2015-01-01

    Quantifying population status is a key objective in many ecological studies, but is often difficult to achieve for cryptic or elusive species. Here, non-invasive genetic capture-mark-recapture (CMR) methods have become a very important tool to estimate population parameters, such as population size and sex ratio. The Eurasian otter (Lutra lutra) is such an elusive species of management concern and is increasingly studied using faecal-based genetic sampling. For unbiased sex ratios or population size estimates, the marking behaviour of otters has to be taken into account. Using 2132 otter faeces of a wild otter population in Upper Lusatia (Saxony, Germany) collected over six years (2006-2012), we studied the marking behaviour and applied closed population CMR models accounting for genetic misidentification to estimate population sizes and sex ratios. We detected a sex difference in the marking behaviour of otters with jelly samples being more often defecated by males and placed actively exposed on frequently used marking sites. Since jelly samples are of higher DNA quality, it is important to not only concentrate on this kind of samples or marking sites and to invest in sufficiently high numbers of repetitions of non-jelly samples to ensure an unbiased sex ratio. Furthermore, otters seemed to increase marking intensity due to the handling of their spraints, hence accounting for this behavioural response could be important. We provided the first precise population size estimate with confidence intervals for Upper Lusatia (for 2012: N = 20 ± 2.1, 95% CI = 16-25) and showed that spraint densities are not a reliable index for abundances. We further demonstrated that when minks live in sympatry with otters and have comparably high densities, a non-negligible number of supposed otter samples are actually of mink origin. This could severely bias results of otter monitoring if samples are not genetically identified.

  16. Fertility preservation: a challenge for IVF-clinics.

    Science.gov (United States)

    Dahhan, Taghride; Mol, Femke; Kenter, Gemma G; Balkenende, Eva M E; de Melker, Annemieke A; van der Veen, Fulco; Dancet, Eline A F; Goddijn, Mariëtte

    2015-11-01

    Acute fertility preservation for women is an interdisciplinary treatment that requires adequate information provision and early referral. This quality management project aimed to improve fertility preservation care by using a practical tool: Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis. Quality management project was executed between May 2011 and July 2013. This project has been executed in a university affiliated IVF-clinic in cooperation with two oncological sites and used a four-step strategy: (1) monitoring baseline referral process, (2) exploring baseline fertility preservation program by Strengths, Weaknesses, Opportunities and Threats' (SWOT)-analysis, (3) setting up a new fertility preservation program and (4) evaluating the new fertility preservation program by means of SWOT-analysis. During the three-months monitoring period, fertility preservation was requested for a total of 126 women. The mean age of the women was 33.8 years old (range 1-42 years old). Most requests came from women who wanted to cryopreserve oocytes because of age-related decline of fertility (n=90; 71%). Most requests for acute fertility preservation concerned women with breast cancer (n=16; 57%). Information leaflets and pre-consultation questionnaires for women improved the quality of first fertility preservation consultation as evaluated by final SWOT-analysis. Collaboration with oncological centres and information about fertility preservation improved the referral process. SWOT-analysis proved useful for setting up a new fertility preservation-program and can be recommended as a tool to improve the management and organisation of new types of reproductive care. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  17. Global assessment of nitrogen fertilizer: The SCOPE/IGBP Nitrogen Fertilizer Rapid Assessment Project

    Institute of Scientific and Technical Information of China (English)

    Arvin R. Mosier; J. Keith Syers; John R. Freney

    2005-01-01

    Nitrogen (N) availability is a key role in food and fiber production. Providing plant-available N through synthetic fertilizer in the 20th and early 21st century has been a major contributor to the increased production required to feed and clothe the growing human population.To continue to meet the global demands and to minimize environmental problems, significant improvements are needed in the efficiency with which fertilizer N is utilized within production systems. There are still major uncertainties regarding the fate of fertilizer N added to agricultural soils and the potential for reducing losses to the environment. Enhancing the technical and economic efficiency of fertilizer N is seen to promote a favorable situation for both agricultural production and the environment, and this has provided much of the impetus for a new N fertilizer project.To address this important issue, a rapid assessment project on N fertilizer (NFRAP) was conducted by SCOPE (the Scientific Committee on Problems of the Environment) during late 2003 and early 2004. This was the first formal project of the International Nitrogen Initiative (INI). As part of this assessment, a successful international workshop was held in Kampala, Uganda on 12 -16 January, 2004. This workshop brought together scientists from around the world to assess the fate of synthetic fertilizer N in the context of overall N inputs to agricultural systems, with a view to enhancing the efficiency of N use and reducing negative impacts on the environment.Regionalization of the assessment highlighted the problems of too little N for crop production to meet the nutrient requirements of sub-Saharan Africa and the oversupply of N in the major rice-growing areas of China. The results of the assessment are presented in a book (SCOPE 65)which is now available to provide a basis for further discussions on N fertilizer.

  18. [The decline of fertility in Western Europe. II. Which fertility rate would be desirable in France? (author's transl)].

    Science.gov (United States)

    Calot, G

    1977-01-01

    A way to try and assess the significance of such or such level in long term fertility is to work out population projections based on a variety of assumptions and to compare their different implications. The age pyramids of France until 2100 that derive from four contrasted evolutions of fertility are studied in the present article: completed fertility in birth cohorts ranging from 1.4 to 2.6 children per woman. While some demographic parameters are not much sensitive to the assumption made for the fertility level (e.g. percent of economically active people in total population), others are closely related to fertility (such as total number of inhabitants, percent of younger people or of older people in total population, annual rate of entry into economically active population). In France, where population density is much lower than in most neighbouring countries, a fertility level that would lay at -- or a little higher than -- replacement (i.e. 2.1 children per woman) can be considered as a desirable target.

  19. Soil microbes and plant fertilization.

    Science.gov (United States)

    Miransari, Mohammad

    2011-12-01

    With respect to the adverse effects of chemical fertilization on the environment and their related expenses, especially when overused, alternative methods of fertilization have been suggested and tested. For example, the combined use of chemical fertilization with organic fertilization and/or biological fertilization is among such methods. It has been indicated that the use of organic fertilization with chemical fertilization is a suitable method of providing crop plants with adequate amount of nutrients, while environmentally and economically appropriate. In this article, the importance of soil microbes to the ecosystem is reviewed, with particular emphasis on the role of plant growth-promoting rhizobacteria, arbuscular mycorrhizal fungi, and endophytic bacteria in providing necessary nutrients for plant growth and yield production. Such microbes are beneficial to plant growth through colonizing plant roots and inducing mechanisms by which plant growth increases. Although there has been extensive research work regarding the use of microbes as a method of fertilizing plants, it is yet a question how the efficiency of such microbial fertilization to the plant can be determined and increased. In other words, how the right combination of chemical and biological fertilization can be determined. In this article, the most recent advances regarding the effects of microbial fertilization on plant growth and yield production in their combined use with chemical fertilization are reviewed. There are also some details related to the molecular mechanisms affecting the microbial performance and how the use of biological techniques may affect the efficiency of biological fertilization.

  20. "Lou soil", a fertile anthropogenic soil with thousands of years of cultivating history

    Science.gov (United States)

    Zhou, J.; Liang, B.; Yan, J.; Zhao, W.

    2012-12-01

    Chinese farmers have a very long history of using manures in their fields. Owing to the long-term addition of manures, an anthropogenic layer was formed on the top of original soil profile (drab soil) in Guanzhong Plains on the south edge of the Loess Plateau, North China. This soil is named the Manural Loessial soil (or Lou soil, "Lou" means the different stories of a building in Chinese). The depth of anthropogenic layer is in range of about 30 to 100 cm depth, which has a close relationship with the soil productivity. This fertile agricultural soil has sustained the agriculture in the region for millenniums. We had determined the organic carbon (SOC) in 7 soil profiles, and found that the depths of anthropogenic layer of were in range of 40 to 71 cm (averaging 59 cm). And the anthropogenic layer became shallower as the profile was far from the village due to less manure application. The organic C stocks in this layer accounted for 69% of organic C stocks in 0-100 cm soil profiles. Organic C stocks in Lou soil was higher than that in the newly cultivated soil developed from loess parent materials. Our 30-day incubation experiment found that addition of synthetic N fertilizer significantly increased the decomposition of SOC in the soils. However, The decomposition rate of SOC in the soil added with manure and inorganic fertilizers for 18-yr (MNPK soil) was significantly lower than in the soils added without fertilizer or inorganic fertilizers (NF soil, and NPK soils). The half-life of the organic C in MNPK soils was also slower than the NF soil, and NPK soil. It indicates that long-term combined application of manure and inorganic fertilizers improves the stabilization of soil organic C. Long-term cultivation has not only increased organic C stocks, but also stabilization of organic C in soil profile. It provides us a unique sample to study the mechanism of accumulation and stabilization of organic C in soil to balance agricultural production and C sequestration

  1. Handling of boar spermatozoa during and after flow cytometric sex-sorting process to improve their in vitro fertilizing ability.

    Science.gov (United States)

    del Olmo, D; Parrilla, I; Gil, M A; Maside, C; Tarantini, T; Angel, M A; Roca, J; Martinez, E A; Vazquez, J M

    2013-09-01

    The objective of this study was to develop an adequate sperm handling protocol in order to obtain a sex-sorted sperm population with an optimal fertilizing ability. For this purpose, different aspects of the sorting procedure were examined. The effects of the high dilution rates (experiment 1), type of collection medium used (experiment 2), and sheath fluid composition (experiment 3) on sorted boar sperm quality and function were evaluated. Sperm quality was assessed by motility and viability tests, whereas sperm function was evaluated by an in vitro fertilization assay which determined the penetration and polyspermy rates as well as the mean number of sperm penetrating each oocyte. In experiment 1, the results obtained indicated that the high dilution rates did not cause a decrease either in the sperm quality parameters evaluated or the in vitro fertilization ability of spermatozoa. In experiment 2, although sperm quality was not affected, fertilizing ability was compromised after sorting, regardless of the collection medium that was used. In the experiment 3, all groups displayed adequate sperm quality values, but higher in vitro fertility parameters were obtained for spermatozoa sorted in presence of EDTA in the sheath fluid and egg yolk (EY) in the collection media when compared with those sorted in absence of these protective agents. No differences in penetration rates between unsorted highly diluted (control) and sorted sperm in the presence of EDTA and EY were observed. In conclusion, fertilizing ability was compromised in sex-sorted sperm. The addition of EDTA to sheath fluid and EY to collection medium improved boar sperm fertilizing ability, and both agents should be included as essential media components in future studies.

  2. [The Marxist outlook on population].

    Science.gov (United States)

    Qin, R

    1984-09-29

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

  3. Fertility and culture in Eastern Europe: a case study of Riga, Latvia, 1867-1881.

    Science.gov (United States)

    Wetherell, C; Plakans, A

    1997-01-01

    This case study examined the influence of cultural and economic conditions on fertility decline in Eastern Europe. Cultural influence on fertility is conceived as the agent with which individuals change behavior which is specific to different ethnic groups and contexts. This study focused on measures of nuptiality and fertility among language and religious groups in Riga, Latvia, in 1867 and 1881. Data were obtained from censuses for Coale's measures of general fertility, marital fertility, the index of illegitimate fertility, and the proportion married. Each variable is a measure of Hutterite fertility as socially unrestrained fertility. Marriage includes the singulate mean age of marriage and the median age at marriage. An average of the urban multipliers for Bavaria, Prussia, Finland, and Sweden, was used to adjust infant mortality. Fertility estimates were higher than the European Fertility Projects. Nuptiality followed the Western European marriage pattern. Nuptiality reflected Hajnal's Western European pattern of late marriage and substantial singlehood. Fertility varied by language group. Fertility was highest among Yiddish speakers and lowest among Latvians. 12.5% of marriages were interfaith marriages. Protestants were the most likely to enter interfaith unions. However, opportunity in the marriage market may have affected mixed marriages. Catholics had the lowest marital fertility. Jews were the most different on a variety of factors. Jews had higher marital fertility and proportion married, and lower female workers, illegitimacy, and proportion single. The authors conclude that the mixed results are insufficient to untangle the effects of culture due to lack of individual level data.

  4. Fertility and contraception in Europe: the case of low fertility in southern Europe.

    Science.gov (United States)

    Shah, I

    1997-03-01

    Demographic trends in Europe can be summarized in terms of a declining proportion of its population in the world total, low fertility, and a slow population growth. Fertility in Western Europe was already below the replacement level in 1970-75 and has remained low. Fertility has substantially declined in Eastern and Southern Europe, with Italy and Spain recording one of the lowest levels (1.2 children per woman) in 1994. Some explanations of the dramatic fertility decline in Southern Europe are: (1) The emancipation of women and their increased participation in the labor force; (2) Economic aspects such as costs for child care and education; and (3) The couple's motivation for low fertility because of the expanded choices for travel and leisure and their concerns for improving their standard of living. Social pressures on childbearing outside marriage remain quite strong; cohabitation and extramarital births is Southern Europe are not as prevalent as in other European regions and there is a trend toward delaying the birth of the first child rather than foregoing childbearing.

  5. Economic development and fertility change in Mexico, 1950-1970.

    Science.gov (United States)

    Hicks, W W

    1974-08-01

    This paper is an attempt to isolate the determinants of fertility in Mexico. Of the variables included, two are significant in accounting for differences in the level of completed fertility in the 32 "states" in 1970. They are the share of the labor force in agriculture, which is directly related to fertility, and the percentage of the population speaking an indigenous language, which shows an inverse relationship.The most important factors acting to reduce total fertility rates over time are increases in life expectancy and declines in the share of the labor force in agriculture. However, based on the estimated linear relationship, these two variables by themselves are not adequate to achieve a rapid decline in fertility in the future.

  6. Genetics, genomics and fertility

    Science.gov (United States)

    In order to enhance the sustainability of dairy businesses, new management tools are needed to increase the fertility of dairy cattle. Genomic selection has been successfully used by AI studs to screen potential sires and significantly decrease the generation interval of bulls. Buoyed by the success...

  7. Fertility and Infertility.

    Science.gov (United States)

    Orgebin-Crist, Marie-Claire; And Others

    In this report, emphasis is placed on major research developments in the reproductive sciences, their impact on the health of individuals as well as on that of society, and on current trends that may provide new opportunities for future research in fertility and infertility. In the first section, major developments in the reproductive sciences are…

  8. Fertility and Infertility.

    Science.gov (United States)

    Orgebin-Crist, Marie-Claire; And Others

    In this report, emphasis is placed on major research developments in the reproductive sciences, their impact on the health of individuals as well as on that of society, and on current trends that may provide new opportunities for future research in fertility and infertility. In the first section, major developments in the reproductive sciences are…

  9. Sperm preparation for fertilization

    NARCIS (Netherlands)

    Gadella, B.M.

    2014-01-01

    Description This book contains 19 chapters that discuss theoretical and applied andrology for domestic, zoo and wild animals. Topics include semen and its constituents; sperm production and harvest; determinants of sperm morphology; sperm preparation for fertilization; practical aspects of semen cry

  10. Mobility, Fertility, and Residential Crowding

    Science.gov (United States)

    Morris, Earl W.

    1977-01-01

    Regression analyses predicting fertility and mobility in a sample of a metropolitan county in New York State indicate that residential mobility serves to release the negative pressure that residential crowding might exert on fertility behavior. (Author)

  11. Agriculture: Nutrient Management and Fertilizer

    Science.gov (United States)

    Fertilizers and soil amendments can be derived from raw materials, composts and other organic matter, and wastes, such as sewage sludge and certain industrial wastes. Overuse of fertilizers can result in contamination of surface water and groundwater.

  12. Sex and Fertility After SCI

    Science.gov (United States)

    ... About Blog Facing Disability Jeff Shannon Donate Experts \\ Sex and Fertility After Spinal Cord Injury Topics Adult ... Spasticity, Physical Therapy-Lokomat Spasticity, Physical Therapy-Lokomat Sex and Fertility After Spinal Cord Injury Sex and ...

  13. Irrigation and fertilization effects on Nantucket Pine Tip Moth (Lepidoptera: Tortricidae) Damage levels and pupal weight in an intensively-managed pine plantation.

    Energy Technology Data Exchange (ETDEWEB)

    Coyle, David, R.; Nowak, John, T.; Fettig, Christopher, J.

    2003-10-01

    The widespread application of intensive forest management practices throughout the southeastern U.S. has increased loblolly pine, Pinus taeda L., yields and shortened conventional rotation lengths. Fluctuations in Nantucket pine tip moth, Rhyacionia frustrana (Comstock), population density and subsequent damage levels have been linked to variations in management intensity. We examined the effects of two practices, irrigation and fertilization, on R. frustrana damage levels and pupal weights in an intensively-managed P. taeda plantation in South Carolina. Trees received intensive weed control and one of the following treatments; irrigation only. fertilization only, irrigation + fertilization, or control. Mean whole-tree tip moth damage levels ranged from <1 to 48% during this study. Damage levels differed significantly among treatments in two tip moth generations in 2001, but not 2000. Pupal weight was significantly heavier in fertilization compared to the irrigation treatment in 2000, but no significant differences were observed in 2001. Tree diameter. height. and aboveground volume were significantly greater in the irrigation + fertilization than in the irrigation treatment after two growing seasons. Our data suggest that intensive management practices that include irrigation and fertilization do not consistently increase R. frustrana damage levels and pupal weights as is commonly believed. However, tip moth suppression efforts in areas adjacent to our study may have partially reduced the potential impacts of R. frustrana on this experiment.

  14. Effects of Different Fertilizing Formulae on Potato

    Directory of Open Access Journals (Sweden)

    Giovanna Cucci

    Full Text Available Trials conducted on potato fertilization at different rates of nitrogen, phosphorus and potassium have shown that the elements able to influence the marketable tuber yield are nitrogen and phosphorus. The potato dry matter, which reflects other quality aspects such as the specific gravity and the starch content, increases with nitrogen fertilization till 150-200 kg ha-1 of nitrogen; beyond those rates values remain nearly unchanged. Dry matter increases also with the application of phosphorus and at low potassium rates. The objective of the research was to test the effect of different rates of N P K fertilizer on yield and some quality traits of potato. The test was conducted at the Campus of the Agricultural Faculty, Bari University, Italy. It involved the comparison of 6 fertilizing formulae N1 P1 K1, N1 P2 K1, N2 P1 K1, N2 P2 K1, N3 P1 K1, N3 P2 K1, obtained from the factorial combination of three nitrogen levels (N = 100-200-300 kg ha-1 and two phosphorus rates (P2O5 = 50-100 kg ha-1 against an unfertilized control N0P0K0. The dose of potassium was constant for all fertilizing formulae (K2O = 300 kg ha-1. The highest total and marketable yields of tubers per plant have been observed at the two highest fertilizing levels (N3 P1 K1, N3 P2 K1, which are not statistically different so that the best treatments is shown to be N3 P1 K1; the trend was similar for the mean weight of tubers. With the various treatments, no difference was observed in terms of yield of tubers belonging to the two first size classes (< 35mm and 35-55mm; what has increased with the fertilizing levels is the yield of tubers greater than 55 mm. Tuber specific gravity show, as expected, a positive correlation with the dry matter percentage. Both parameters increased shifting from the control to the N2 P2 K1 and decreased at the highest N level, without any difference being observed with the change in the P rate. The highest starch percentage (20.5% was also observed in the

  15. Third world programs confront adolescent fertility.

    Science.gov (United States)

    1978-08-01

    Recently, there have been efforts to identify workable youth programs and effective research projects that could deal with the problem of adolescent fertility. Typical objectives identified at various conferences concerned with this problem included the following: 1) focus attention on the adverse medical and socioeconomic efforts of early pregnancy; 2) draw attention to the current dimensions of adolescent fertility and its changing patterns; 3) encourage development of programs; and 4) impress decision makers with the importance of programs for adolescents. These conferences express a sense of urgency in developing programs before teen-age pregnancy reaches epidemic proportions. Most of the projects already underway are still pilot efforts and have an impact on a very small sector of the population. Yet, they are positive steps toward a solution of the rising problems of adolescent fertility and help to identify workable solutions. A few of these projects -- underway in Colombia, Argentina, Chile, Cost Rica, Guatemala and Mexico -- are reviewed. The consensus of all conferences held to date has been that cross-cultural interchanges is crucial to the spread of programs and ideas that can be adapted to local conditions. 2 key recommendations have emerged from a meeting of donor and support agencies held in Washington, D.C. in May: 1) a major conference should take place during the International Year of the Child (1979) that would focus on early sexual activity and fertility and 2) an Adolescent Fertility Council should be appointed. An Adolescent Fertility Council would provide a structure to correlate and stimulate interaction, while recognizing that country and culture specific programs are essential.

  16. A method of obtaining dietary data for slow worms (Anguis fragilis) by means of non-harmful cooling and results from a Danish population

    DEFF Research Database (Denmark)

    Pedersen, Iben; Jensen, Jan Kjærgaard; Toft, Søren

    2009-01-01

    Diet composition of slow worms (Anguis fragilis) from a Danish population was recorded from May to September 2006. Slow worms were maintained in cool conditions (at 8°C) for a maximum of 126 h, which made approximately half of the animals regurgitate. The method worked equally well on juveniles...... types was tested on juveniles in a laboratory experiment. Mealworms gave a significantly lower gain in mass and snout-vent length than slugs, earthworms and a mix of all three prey types. A supplementary experiment revealed that slow worms from the present population completely rejected mealworms...

  17. Reproduction, fertility and socio-economic development

    Directory of Open Access Journals (Sweden)

    Meshkani Z

    1997-07-01

    Full Text Available The rapid growth of population in the third world countries specially in recent decades has posed an important social problem. There have been some attempts to propose solutions for this problem by scientists from various disciplines. However, it seems that an integrated approach calling for collaboration of various efforts can be more fruitful. In this work, we study the relation of women fertility and socio-economical indices along with government's programmed efforts in the third world countries. Employing a statistical approach, we show that development indices such as gross national product, infant mortality rate, education enrolment, and access to mass media along with government's programmed efforts are effective in reducing the fertility rate, but more important is the interaction between these factors. Thus, an integrated approach emerges as a better solution to population control

  18. A demographic explanation for the recent rise in European fertility.

    Science.gov (United States)

    Bongaarts, John; Sobotka, Tomáš

    2012-01-01

    Between 1998 and 2008 European countries experienced the first continent-wide increase in the period total fertility rate (TFR) since the 1960s. After discussing period and cohort influences on fertility trends, we examine the role of tempo distortions of period fertility and different methods for removing them. We highlight the usefulness of a new indicator: the tempo- and parity-adjusted total fertility rate (TFRp*). This variant of the adjusted total fertility rate proposed by Bongaarts and Feeney also controls for the parity composition of the female population and provides more stable values than the indicators proposed in the past. Finally, we estimate levels and trends in tempo and parity distribution distortions in selected countries in Europe. Our analysis of period and cohort fertility indicators in the Czech Republic, Netherlands, Spain, and Sweden shows that the new adjusted measure gives a remarkable fit with the completed fertility of women in prime childbearing years in a given period, which suggests that it provides an accurate adjustment for tempo and parity composition distortions. Using an expanded dataset for ten countries, we demonstrate that adjusted fertility as measured by TFRp* remained nearly stable since the late 1990s. This finding implies that the recent upturns in the period TFR in Europe are largely explained by a decline in the pace of fertility postponement. Other tempo-adjusted fertility indicators have not indicated such a large role for the diminishing tempo effect in these TFR upturns. As countries proceed through their postponement transitions, tempo effects will decline further and eventually disappear, thus putting continued upward pressure on period fertility. However, such an upward trend may be obscured for a few years by the effects of economic recession.

  19. International fertility change: new data and insights from the developmental idealism framework.

    Science.gov (United States)

    Thornton, Arland; Binstock, Georgina; Yount, Kathryn M; Abbasi-Shavazi, Mohammad Jalal; Ghimire, Dirgha; Xie, Yu

    2012-05-01

    Many scholars have offered structural and ideational explanations for the fertility changes occurring around the world. This paper focuses on the influence of developmental idealism-a schema or set of beliefs endorsing development, fertility change, and causal connections between development and fertility. Developmental idealism is argued to be an important force affecting both population policy and the fertility behavior of ordinary people. We present new survey data from ordinary people in six countries-Argentina, China, Egypt, Iran, Nepal, and the United States-about the extent to which developmental idealism is known and believed. We ask individuals if they believe that fertility and development are correlated, that development is a causal force in changing fertility levels, and that fertility declines enhance the standard of living and intergenerational relations. We also ask people about their expectations concerning future trends in fertility in their countries and whether they approve or disapprove of the trends they expect. The data show widespread linkage in the minds of ordinary people between fertility and development. Large fractions of people in these six settings believe that fertility and development are correlated, that development reduces fertility, and that declines in fertility foster development. Many also expect and endorse future declines in fertility.

  20. Cost effectiveness analysis of a population based screening programme for asymptomatic Chlamydia trachomatis infections in women by means of home obtained urine specimens

    NARCIS (Netherlands)

    van Valkengoed, IGM; Postma, MJ; Morre, SA; van den Brule, AJC; Meijer, CJLM; Bouter, LM; Boeke, AJP

    Objectives: To evaluate the cost effectiveness of a systematic screening programme for asymptomatic Chlamydia, trachomatis infections in a female inner city population. To determine the sensitivity of the cost effectiveness analysis to variation in the probability of developing sequelae. Methods: A

  1. Cost effectiveness analysis of a population based screening programme for asymptomatic Chlamydia trachomatis infections in women by means of home obtained urine specimens

    NARCIS (Netherlands)

    van Valkengoed, IGM; Postma, MJ; Morre, SA; van den Brule, AJC; Meijer, CJLM; Bouter, LM; Boeke, AJP

    2001-01-01

    Objectives: To evaluate the cost effectiveness of a systematic screening programme for asymptomatic Chlamydia, trachomatis infections in a female inner city population. To determine the sensitivity of the cost effectiveness analysis to variation in the probability of developing sequelae. Methods: A

  2. Using fertile couples as embryo donors: An ethical dilemma.

    Science.gov (United States)

    Alizadeh, Leila; Omani Samani, Reza

    2014-03-01

    The use of donated embryos has offered hope for infertile couples who have no other means to have children. In Iran, fertility centers use fertile couples as embryo donors. In this paper, the advantages and disadvantages of this procedure will be discussed. We conclude that embryo-donation should be performed with frozen embryos thus preventing healthy donors from being harmed by fertility drugs. There must be guidelines for choosing the appropriate donor families. In countries where commercial egg donation is acceptable, fertile couples can be procured as embryo donors thus fulfilling the possible shortage of good quality embryos. Using frozen embryos seems to have less ethical, religious and legal problems when compared to the use of fertile embryo donors.

  3. Contemporary Fertility Patterns and First-Birth Timing among Mexican-Origin Women

    Science.gov (United States)

    Batson, Christie D.

    2013-01-01

    This article examines first-birth timing among Mexican women in the United States over two birth cohorts. Currently, Mexican women are one of a small group that maintains above-replacement fertility in the United States, contributing to both Mexican population growth and overall national population growth. Yet, the fertility timing of Mexican…

  4. Fertility problems and risk of gestational diabetes mellitus

    DEFF Research Database (Denmark)

    Holst, Signe; Kjær, Susanne K; Jørgensen, M. E.

    2016-01-01

    Objective To determine whether women with a history of fertility problems have a higher risk of gestational diabetes mellitus (GDM) than women without a history of fertility problems after adjustment for maternal factors. Design Nationwide population-based cohort study. Setting Not applicable...... of diabetes, level of education, and smoking during pregnancy. Result(s) In total, 7,433 (2%) pregnant women received a diagnosis of GDM. Multivariate analysis showed that pregnant women with a history of fertility problems had a statistically significantly higher risk of GDM than pregnant women without...

  5. [Association of the meaning of life with satisfaction, the occurrence of subjective complaints and the family's economic status in the population of lower secondary school students].

    Science.gov (United States)

    Zawadzka, Dorota; Stalmach, Magdalena; Oblacińska, Anna; Tabak, Izabela

    Feeling of meaning in life is extremely crucial factor of mental health. The lack of it can result in various disorders. Many authors, especially those connected with current of humanistic psychology underline the teenagers' life sense. The aim of the paper was to examine the level of satisfaction with life, the frequency of psychosomatic complaints by junior high school students as well as the estimation of economical status of family and the analysis of meaning in life with above mentioned factors. The research was carried out in 2015 at 70 schools from all over the country, in group of 3695 lower secondary school students of I-III classes at the age of 13-17 (M=14,9; SD=0,87). The analysis connected with meaning in life using the shorten version of Purpose in Life Test (PIL) as well as analysis of life satisfaction using Cantril scale were taken up. What is more, the subjective physical complaints using single-factor shorten scale and economic status of family with the usage of material resources FAS scale (Family Affluence Scale) were examined. The statistical analysis included a one-way analysis of variance (ANOVA), t-student test post-hoc test as well as multivariate logistic regression model. The average level of meaning in life among the examined students was 24,7 points (the summary scale 0-36 points), the boys achieved higher score than girls. The students satisfied with life (t=28,0; plife than students who were dissatisfied with their life, often or fairly suffer from health complaints and live in families of at most average level of affluence. The meaning in life is positively connected with satisfaction with life, lack of subjective complaints and family affluence. Because there is a lack of analysis linked with school teenagers' meaning in life in Polish literature, another research involved not only shorten but also full version of this tool should be conducted.

  6. MANAGEMENT OF IRRIGATION AND NITROGEN FERTILIZERS TO REDUCE AMMONIA VOLATILIZATION

    Directory of Open Access Journals (Sweden)

    Fernando Viero

    2015-12-01

    Full Text Available ABSTRACT Nitrogen losses by ammonia (NH3 volatilization can be reduced by appropriate irrigation management or by alternative N sources, replacing urea. The objective of this study was to evaluate the efficiency of irrigation management and N source combinations in decreasing NH3 volatilization from an Argissolo Vermelho Distrófico típico cultivated for 28 years with black oat (Avena strigosa and maize (Zea mays, under no-tillage in the region of Depressão Central, Rio Grande do Sul, Brazil. The experiment was arranged in a randomized block design with split plots with three replications, where the main plots consisted of irrigation systems: no irrigation; irrigation immediately before and irrigation immediately after fertilization. The subplots were treated with different N sources: urea, urea with urease inhibitor and slow-release fertilizer, at an N rate of 180 kg ha-1, broadcast over maize, plus a control treatment without N fertilization. Ammonia volatilization was assessed using semi-open static collectors for 1, 2, 4, 6, and 10 days after N fertilization. In general, more than 90 % of total NH3-N losses occurred until three days after N fertilization, with peaks up to 15.4 kg ha-1 d-1. The irrigation was efficient to reduce NH3 losses only when applied after N fertilization. However, reductions varied according to the N fertilizer, and were higher for urea (67 % and slightly lower for urea with urease inhibitor (50 % and slow-release fertilizer (40 %, compared with the mean of the treatments without irrigation and irrigation before fertilization. The use of urea with urease inhibitor instead of urea was only promising under volatilization-favorable conditions (no irrigation or irrigation before N fertilization. Compared to urea, slow-release fertilizer did not reduce ammonia volatilization in any of the rainfed or irrigated treatments.

  7. Population Subdivision of Japanese Flounder Paralichthys olivaceus in the Pacific Coast of Tohoku Japan Detected by Means of Mitochondrial Phylogenetic Information

    Directory of Open Access Journals (Sweden)

    Yuya Shigenobu

    2013-01-01

    Full Text Available This study deals with mitochondrial phylogenetic information of Japanese flounder in the Pacific coast of Tohoku Japan to estimate the genetic population subdivision that was undetectable by conventional population statistics. We determined complete sequences of mitochondrial NADH dehydrogenase subunit-2 (ND2 and subunit-5 (ND5 genes for 151 individuals from northern (Aomori and Iwate prefectures, 40–41°N and southern (Miyagi and Fukushima prefectures, 37–38°N waters. Samples from both waters showed high genetic diversity, including 126 haplotypes. These haplotypes were located at mixed and nested positions on an inferred phylogenetic tree, and traditional F-statistics indicated no significant population divergence (φST = −0.00335, p > 0.05, corroborating our previous study. Three variable sites, however, showed significant base composition heterogeneity between samples from the northern and southern waters (Fisher’s exact-test, p < 0.01. Nucleotide substitutions at the three sites converged on an apical clade, which consisted of the five southern individuals, whereas its sister clade consisted only of the three northern individuals. This phylogenetic information corroborates previous ecological studies indicating the presence of separate stocks in the northern and southern waters.

  8. 施氮对南疆干旱荒漠绿洲枣棉间作棉田根际微生物区系的影响研究%Effects of Nitrogen Fertilizer on Rhizosphere Microbial Populations under Cotton Intercropped with Red Date in Arid Desert Oasis of Southern Xinjiang

    Institute of Scientific and Technical Information of China (English)

    汤秋香; 徐海东; 石大伟; 林涛; 高文伟; 田立文; 郭仁松; 李玉; 叶强涛; 林毅

    2014-01-01

    [Objective]This study aimed to determine the number of microorganisms of cotton rhizosphere in a soil at various amounts of applied nitrogen fertilizer in a red date-cotton intercropping system. [Method] In the field experiment, nitrogen fer-tilizer was applied at 0, 150, 300, 450, 600, and 750 kg/hm2, respectively. The dy-namic changes of the populations of bacteria, fungi and actinomycetes at the rhizo-sphere of cotton intercropped with red date were investigated. [Result] Microbial populations significantly increased at nitrogen fertilizer of 300 and 450 kg/hm2 during bud, flowering and bol opening periods. The numbers of bacteria and actinomycetes were higher during flowering and bol opening stages than at bud stage. The num-ber of fungi slightly changed during the entire growth period. Appropriate amount of nitrogen fertilizer (300 to 600 kg/hm2) was favorable to the survival of the microor-ganisms in the soil under the intercropping system. [Conclusion] The study provides a guideline for screening and determining the optimum amount of applied nitrogen fertilizer.%[目的]为明确枣棉间作模式下不同施氮量对棉花根际微生物的影响。[方法]通过田间小区试验,研究0、150、300、450、600、750 kg/hm26种施氮水平对枣树‖棉花模式中棉花根际土壤中细菌、真菌和放线菌数量的变化动态。[结果]300和450 kg/hm2施氮量能显著增加蕾期、花期和吐絮期微生物总数量。细菌和放线菌在整个生育期中蕾期数量最少,铃期和花期较高,吐絮期次之。真菌数量各个时期变化不大。适宜施氮量能增加铃期枣棉间作交际行棉花根际土微生物数量。[结论]该研究可为枣棉间作系统合理施用氮肥提供科学依据。

  9. Social mobility and fertility

    Directory of Open Access Journals (Sweden)

    Gianpiero Dalla Zuanna

    2007-12-01

    Full Text Available Intra- and inter-generational social mobility have in the past played an important role in attempts to explain fertility behaviour, and continue to do so today. The opinions expressed by social scientists in the first part of the 20th century are renewed and confirmed. More specifically: (1 intra-generational social mobility has been reinforced by the personal well-being aspirations and job careers of women; (2 status anxiety parents feel for their children pushes fertility down in large areas of the developed world (mainly in southern European and eastern Asian countries. Therefore, the provocative idea of Ariès that in the rich world, the child-king has now been replaced by the couple-queen does not perfectly hold.

  10. Religion and fertility: The French connection

    Directory of Open Access Journals (Sweden)

    Thomas Baudin

    2015-02-01

    Full Text Available Background: France has been among the first countries to become sacularized but has preserved a Catholic identity. Before 2008, French laws made it very difficult to collect data on an individual's religious affiliation. The dataset "Enquete Mode de Vie des Francais" is thefirst allowing one to collect such data. Objective: I investigate the impact that being a Catholic has on fertility in France. I answer two main questions: (i Do Catholic people have more children than others? (ii Why is this the case? Methods: Fertility is measured by the number of children ever born. I use the dataset "Enquete Mode de Vie des Francais" and Zero-Inflated Poisson regression models. Individual religiosity is approximated by the attendance at religious services. Results: I first show that practicing Catholics have more children than the rest of the population, while this is not verified for nominal Catholics. I also construct two variables allowing me to detect that particularized ideology mechanisms (Goldscheider 1971 can explain in part why religion has an impact on fertility in my dataset. Nevertheless, I cannot exclude the social interaction hypothesis. The multivariate analysis I provide also validates the main mechanisms of the rational actor model. Conclusions: I implement several robustness checks showing that my main results are robust to changing my regression model (ordered probit and linear regressions and the way religiousness and fertility are measured.

  11. Preliminary assessment on exposure of four typical populations to potentially toxic metals by means of skin wipes under the influence of haze pollution.

    Science.gov (United States)

    Cao, Zhiguo; Wang, Mengmeng; Chen, Qiaoying; Zhang, Yajie; Dong, Wenjing; Yang, Tianfang; Yan, Guangxuan; Zhang, Xin; Pi, Yunqing; Xi, Benye; Bu, Qingwei

    2017-09-21

    To investigate the exposure risk of human beings to nine potentially toxic metals (PTMs), namely, Cu, Cr, Zn, As, Cd, Pb, Ni, Mn, and Co, skin wipe samples were collected from four types of populations, namely, children, undergraduates, security guards, and professional drivers, under different haze pollution levels in Xinxiang, China by using Ghost wipes. The Ghost wipes were quantitatively analyzed by inductively coupled plasma mass spectrometry (ICP-MS) after microwave digestion. Generally, Zn (ND-1350μg/m(2) for undergraduates, ND-2660μg/m(2) for security guards, ND-2460μg/m(2) for children, and ND-2530μg/m(2) for professional drivers) showed the highest concentration among the four populations, followed by Cu (0.02-83.4μg/m(2) for undergraduates, ND-70.2μg/m(2) for security guards, 23.2-487μg/m(2) for children, and ND-116μg/m(2) for professional drivers). As (ND-5.7μg/m(2) for undergraduates, ND-2.3μg/m(2) for security guards, ND-21.1μg/m(2) for children, and ND-11.0μg/m(2) for professional drivers) and Co (ND-6.0μg/m(2) for undergraduates, ND-7.9μg/m(2) for security guards, ND-13.4μg/m(2) for children, and ND-2.1μg/m(2) for professional drivers) showed the lowest concentrations in all populations. Remarkable differences were found among the four populations and PTM levels decreased in the following order: children, professional drivers, security guards, and undergraduates. Gender variation was discovered for undergraduates and children. Generally, PTM contamination in skin wipes collected during a light haze pollution level was generally higher than that during a heavy haze pollution level, but PTM contamination was comparable between the two haze pollution levels for children. Non-carcinogenic exposure risks to As, Cd, and Pb for all populations were higher than those for the other six elements but all of them were within the acceptable safety threshold, indicating no apparent non-carcinogenic risk. Copyright © 2017. Published by Elsevier B.V.

  12. Asociación entre la tasa de autofecundación y la frecuencia de larvas malformadas en poblaciones cultivadas del ostión del norte Argopecten purpuratus (Lamarck, 1819 Association between self-fertilization rates and the frequency of malformed larvae in farmed populations of the northern scallop Argopecten purpuratus (Lamarck, 1819

    Directory of Open Access Journals (Sweden)

    Christopher Concha

    2011-07-01

    separately from the fifth or later spawning pulses. Oocytes were fertilized with sperm from another individual, forming families of complete siblings. Selfing rates were verified by the proportion of cleaving oocytes in a non-fertilized sample. Self-fertilization ranged from 0 to 100% among families, with a normal distribution. The proportion of malformed larvae was distributed randomly among the families analyzed, but was negatively correlated - moderately but significantly - with the selfing rate and the mean water temperature of the culture. These results suggest that self-fertilization in scallop families can favor greater homeostasis of larval development.

  13. Slow-Release Fertilizer

    Science.gov (United States)

    1998-01-01

    Under an SBIR (Small Business Innovative Research), ZeoponiX, Inc., introduced ZeoPro. This product is used as a fertilizer/soil amendment for golf courses, ball fields, greenhouse and horticultural uses. A combination of superior growth medium and soil conditioner allow for nutrient supplementation and high efficiency delivery of nutrients throughout the plant. ZeoPro provides a balanced nutrient system for major, minor, and trace nutrients.

  14. Human Fertility Increases with the Marital-radius

    DEFF Research Database (Denmark)

    Labouriau, Rodrigo; Amorim, António

    2008-01-01

    We report a positive association between marital radius (distance between mates' birthplaces) and fertility detected in a large population. Spurious association due to socioeconomic factors is discarded by a conditional analysis involving income, education, and urbanicity. Strong evidence...... of consanguinity's deleterious effects affecting an entire human population is provided...

  15. Environmental friendly nitrogen fertilization

    Institute of Scientific and Technical Information of China (English)

    Avi; Shaviv

    2005-01-01

    With the huge intensification of agriculture and the increasing awareness to human health and natural resources sustainability, there was a shift towards the development of environmental friendly N application approaches that support sustainable use of land and sustain food production.The effectiveness of such approaches depends on their ability to synchronize plant nitrogen demand with its supply and the ability to apply favored compositions and dosages of N-species.They are also influenced by farming scale and its sophistication, and include the following key concepts: (i) Improved application modes such as split or localized ("depot") application; (ii) use of bio-amendments like nitrification and urease inhibitors and combinations of (i) and (ii); (iii) use of controlled and slow release fertilizers; (iv) Fertigation-fertilization via irrigation systems including fully automated and controlled systems; and (v) precision fertilization in large scale farming systems. The paper describes the approaches and their action mechanisms and examines their agronomic and environmental significance. The relevance of the approaches for different farming scales, levels of agronomic intensification and agro-technical sophistication is examined as well.

  16. MEDIA CONCERN AND TRENDS OF FERTILITY IN BANGLADESH

    Directory of Open Access Journals (Sweden)

    Mohammad Morad

    2014-05-01

    Full Text Available This paper analyses how the media interprets Bangladeshian fertility trends by analyzing 11 online available articles from two Bangladeshi leading dailies, The Daily Star and the Prothom Alo. The exploration of the newspaper articles reveals that print media in Bangladesh has shown concern notably on the present scenario of the country’s declining fertility trend. It has been observed from the newspaper clippings that both population growth rate and fertility rate are gradually declining in Bangladesh which they explain as a matter of great satisfaction. Drawing on examples from South Asia, the articles explain that Bangladesh has a remarkable achievement in fertility reduction compared to India and Pakistan. However, almost all of the articles have expressed concern over the population bomb of Bangladesh. The newspapers also report that though fertility is declining at the national level, significant variation exists at the regional level and among different socio economic groups. The fertility rate is reported to be very high in the urban shanties and poverty-stricken rural areas. In this regard, the clippings have often criticized the government activities, especially governmental population control programme.

  17. An Iterative Algorithm for Efficient Estimation of the Mean of a Normal Population Using Computational-Statistical Intelligence & Sample Counterpart of Rather-Very-Large Though Unknown Coefficient of Variation with a Small- Sample

    Directory of Open Access Journals (Sweden)

    Ashok Sahai

    2016-02-01

    Full Text Available This paper addresses the issue of finding the most efficient estimator of the normal population mean when the population “Coefficient of Variation (C. V.” is ‘Rather-Very-Large’ though unknown, using a small sample (sample-size ≤ 30. The paper proposes an “Efficient Iterative Estimation Algorithm exploiting sample “C. V.” for an efficient Normal Mean estimation”. The MSEs of the estimators per this strategy have very intricate algebraic expression depending on the unknown values of population parameters, and hence are not amenable to an analytical study determining the extent of gain in their relative efficiencies with respect to the Usual Unbiased Estimator (sample mean ~ Say ‘UUE’. Nevertheless, we examine these relative efficiencies of our estimators with respect to the Usual Unbiased Estimator, by means of an illustrative simulation empirical study. MATLAB 7.7.0.471 (R2008b is used in programming this illustrative ‘Simulated Empirical Numerical Study’.DOI: 10.15181/csat.v4i1.1091

  18. 繁殖方法对滇I型粳稻不育系群体中可育株类型和频率的影响%Effects of Multiplying Methods on Type and Frequency of Fertile Plants in Populations of Japonica Dian I-type CMS Lines in Rice

    Institute of Scientific and Technical Information of China (English)

    文建成; 黄大军; 陆定科; 谭亚玲; 洪汝科; 谭学林

    2011-01-01

    连续4a调查了以袋繁和自繁方式生产的4个滇I型不育系的11个群体,发现"可育株"的出现频率为0.087 1%.其表型与相应保持系一致.采用测交和分子标记技术分析了这些"可育株"的基因型,发现袋繁不育系群体存在核恢复基因位点基因型为r矿的"保持株"和Rf/rf的"回复株"2种类型,而自繁不育系群体还新出现基因型为RfRf的"纯合株"类型.与袋繁群体比,自繁群体出现"可育株"的频率提高了74.7%.其中"保持株"频率提高了42.6%,"回复株"频率提高了149.3%.基于不育系繁殖方法不同,不育系中出现"可育株"混杂的几率不同,为获得高纯度的不育系种子,滇I型不育系繁殖应在袋繁基础上,扩大自繁群体,减少自繁次数.%It was found that the ratio of fertile plants (FP) was 0.087 1% on average based on the investigation of 11 populations of four japonica Dian Ⅰ-type CMS Lines (CMS-D1) generated by bagged pollination multiplication (BPM) and natural pollination multiplication (NPM) for four years (2005-2008), and the phenotype of fertile plants was similar to that of maintainer plants. The analysis based on selfing, testcrossing and DNA marker techniques showed that there were two genotypes, i.e. , rf/rf ( maintainer plants) and Rf/rf (revertants), for the fertile plants in the populations generated by BPM, but in the populations generated by NPM, besides the above two genotypes, a new genotype, Rf/Rf ( homozygous plants), was found. In comparison with the BPM populations, the NPM populations had a higher ratio of fertile plants by 74.7%, of maintainer plants by 42.6% and of revertants by 149.3%. Since different methods of multiplication results in a different degree of impurity of fertile plants in CMS populations, it is necessary to enlarge the size of NPM population on the basis of BPM and lessen the multiplying times to ensure a high seed purity in the multiplication of CMS-D1.

  19. Relationships between nutrient-related plant traits and combinations of soil N and P fertility measures.

    Directory of Open Access Journals (Sweden)

    Yuki Fujita

    Full Text Available Soil fertility and nutrient-related plant functional traits are in general only moderately related, hindering the progress in trait-based prediction models of vegetation patterns. Although the relationships may have been obscured by suboptimal choices in how soil fertility is expressed, there has never been a systematic investigation into the suitability of fertility measures. This study, therefore, examined the effect of different soil fertility measures on the strength of fertility-trait relationships in 134 natural plant communities. In particular, for eight plot-mean traits we examined (1 whether different elements (N or P have contrasting or shared influences, (2 which timescale of fertility measures (e.g. mineralization rates for one or five years has better predictive power, and (3 if integrated fertility measures explain trait variation better than individual fertility measures. Soil N and P had large mutual effects on leaf nutrient concentrations, whereas they had element-specific effects on traits related to species composition (e.g. Grime's CSR strategy. The timescale of fertility measures only had a minor impact on fertility-trait relationships. Two integrated fertility measures (one reflecting overall fertility, another relative availability of soil N and P were related significantly to most plant traits, but were not better in explaining trait variation than individual fertility measures. Using all fertility measures together, between-site variations of plant traits were explained only moderately for some traits (e.g. 33% for leaf N concentrations but largely for others (e.g. 66% for whole-canopy P concentration. The moderate relationships were probably due to complex regulation mechanisms of fertility on traits, rather than to a wrong choice of fertility measures. We identified both mutual (i.e. shared and divergent (i.e. element-specific and stoichiometric effects of soil N and P on traits, implying the importance of explicitly

  20. Relationships between nutrient-related plant traits and combinations of soil N and P fertility measures.

    Science.gov (United States)

    Fujita, Yuki; van Bodegom, Peter M; Witte, Jan-Philip M

    2013-01-01

    Soil fertility and nutrient-related plant functional traits are in general only moderately related, hindering the progress in trait-based prediction models of vegetation patterns. Although the relationships may have been obscured by suboptimal choices in how soil fertility is expressed, there has never been a systematic investigation into the suitability of fertility measures. This study, therefore, examined the effect of different soil fertility measures on the strength of fertility-trait relationships in 134 natural plant communities. In particular, for eight plot-mean traits we examined (1) whether different elements (N or P) have contrasting or shared influences, (2) which timescale of fertility measures (e.g. mineralization rates for one or five years) has better predictive power, and (3) if integrated fertility measures explain trait variation better than individual fertility measures. Soil N and P had large mutual effects on leaf nutrient concentrations, whereas they had element-specific effects on traits related to species composition (e.g. Grime's CSR strategy). The timescale of fertility measures only had a minor impact on fertility-trait relationships. Two integrated fertility measures (one reflecting overall fertility, another relative availability of soil N and P) were related significantly to most plant traits, but were not better in explaining trait variation than individual fertility measures. Using all fertility measures together, between-site variations of plant traits were explained only moderately for some traits (e.g. 33% for leaf N concentrations) but largely for others (e.g. 66% for whole-canopy P concentration). The moderate relationships were probably due to complex regulation mechanisms of fertility on traits, rather than to a wrong choice of fertility measures. We identified both mutual (i.e. shared) and divergent (i.e. element-specific and stoichiometric) effects of soil N and P on traits, implying the importance of explicitly

  1. 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

  2. Ethnic Dimensions of Guatemala's Stalled Transition: A Parity-Specific Analysis of Ladino and Indigenous Fertility Regimes.

    Science.gov (United States)

    Grace, Kathryn; Sweeney, Stuart

    2016-02-01

    In some contemporary populations, fertility levels appear to plateau, with women maintaining a consistently high level of fertility for a relatively extended period. Because this plateau does not reflect the historical patterns observed in Europe, the focus of most studies on fertility patterns, mechanisms underlying the plateau and the reinstatement of a decline have not been fully explored and are not fully understood. Through the construction of fertility histories of 25,000 women using multiple years of health survey data, we analyze some of the components of stalled fertility as they pertain to Guatemala, the only Central American country to have experienced a stalled fertility decline.

  3. Development of the knowledge of fertility and fertility preservation scale

    Directory of Open Access Journals (Sweden)

    McNees P

    2012-04-01

    Full Text Available Angela Jukkala1, Karen Meneses1, Andres Azuero1, June Cho1, Patrick McNees1,21School of Nursing, 2School of Health Professions, University of Alabama at Birmingham, Birmingham, AL, USAObjective: Infertility is a severe and often underestimated consequence of successful treatment for breast cancer. Ensuring young breast cancer survivors receive patient-centered health information on the impact of treatment on fertility and fertility preservation options in a timely manner is a critical component of high quality nursing care. The objective of this manuscript is to report the process used to develop and examine the reliability and validity of an instrument to measure a breast cancer survivor’s self-assessed knowledge of fertility and fertility preservation.Design: A scale development and descriptive study.Setting: Online and global.Participants: Ninety-two young breast cancer survivors (ages 25–45 years.Methods: Participants completed the Knowledge of Fertility and Fertility Preservation (KF Scale as part of their participation in a larger study, the Fertility Cancer Project (FCP.Results: An exploratory factor analysis revealed five domains: normal reproductive function; general information about fertility; cancer treatment factors affecting fertility; infertility information; and alternative parenting options. A confirmatory factor analysis confirmed the validity of the construct with a demonstrated good fit between the factor structure of the new scale and the observed data. Many participants self-assessed their overall knowledge of fertility and fertility preservation as “a little” and the majority rated their knowledge of infertility information as “a little”.Conclusion: The KF Scale can be used to provide useful information to support health care professionals in the development of patient-centered education that is responsive to the unique needs of each young breast cancer survivor. The initial testing of the KF Scale indicates

  4. Convergence in fertility of South Africans and Mozambicans in rural South Africa, 1993–2009

    Directory of Open Access Journals (Sweden)

    Michel Garenne

    2013-01-01

    Full Text Available Background: Although there are significant numbers of people displaced by war in Africa, very little is known about long-term changes in the fertility of refugees. Refugees of the Mozambican civil war (1977–1992 settled in many neighbouring countries, including South Africa. A large number of Mozambican refugees settled within the Agincourt sub-district, underpinned by a Health and Socio-demographic Surveillance Site (AHDSS, established in 1992, and have remained there. The AHDSS data provide a unique opportunity to study changes in fertility over time and the role that the fertility of self-settled refugee populations plays in the overall fertility level of the host community, a highly relevant factor in many areas of sub-Saharan Africa. Objectives: To examine the change in fertility of former Mozambican self-settled refugees over a period of 16 years and to compare the overall fertility and fertility patterns of Mozambicans to host South Africans. Design: Prospective data from the AHDSS on births from 1993 to 2009 were used to compare fertility trends and patterns and to examine socio-economic factors that may be associated with fertility change. Results: There has been a sharp decline in fertility in the Mozambican population and convergence in fertility patterns of Mozambican and local South African women. The convergence of fertility patterns coincides with a convergence in other socio-economic factors. Conclusion: The fertility of Mozambicans has decreased significantly and Mozambicans are adopting the childbearing patterns of South African women. The decline in Mozambican fertility has occurred alongside socio-economic gains. There remains, however, high unemployment and endemic poverty in the area and fertility is not likely to decrease further without increased delivery of family planning to adolescents and increased education and job opportunities for women.

  5. Female fertility affects men's linguistic choices.

    Directory of Open Access Journals (Sweden)

    Jacqueline M Coyle

    Full Text Available We examined the influence of female fertility on the likelihood of male participants aligning their choice of syntactic construction with those of female confederates. Men interacted with women throughout their menstrual cycle. On critical trials during the interaction, the confederate described a picture to the participant using particular syntactic constructions. Immediately thereafter, the participant described to the confederate a picture that could be described using either the same construction that was used by the confederate or an alternative form of the construction. Our data show that the likelihood of men choosing the same syntactic structure as the women was inversely related to the women's level of fertility: higher levels of fertility were associated with lower levels of linguistic matching. A follow-up study revealed that female participants do not show this same change in linguistic behavior as a function of changes in their conversation partner's fertility. We interpret these findings in the context of recent data suggesting that non-conforming behavior may be a means of men displaying their fitness as a mate to women.

  6. Fertility and marriage behavior in Israel: Diversity, change, and stability

    Directory of Open Access Journals (Sweden)

    Barbara Okun

    2013-03-01

    Full Text Available BACKGROUND Based on aggregate statistics, the population of Israel, as compared to all or most other developed societies, has very high levels of fertility and marriage (e.g. TFR of 2.96 in 2009 and only 9.7Š never married among women aged 40-44 in 2009. However, studying aggregate demographic measures is problematic, because Israel is an extremely heterogeneous society, with family formation patterns differing greatly across numerically important social groups. Until now, little has been documented about the basic fertility and marriage behavior of different population groups. OBJECTIVE We describe the fertility and marriage behavior of populations in Israel, broken down by nationality, religion, religiosity and nativity-status. Although our main focus is on a detailed presentation of fertility patterns, we also look at marriage behavior, as it is closely related to fertility in Israel. METHODS We analyze recently available annual data from the Israel Social Surveys for 2002-2009, which, for the first time in several decades,, provides detailed information on family and household demographic behavior and direct information on level of religiosity. We focus primarily on comparisons across cohorts born from the late 1940s to the late 1960s and between periods in the early and late 2000s. RESULTS We provide a detailed portrait of striking diversity in fertility and marriage behavior across population groups, along with important patterns of change and stability across cohorts and over time. We document findings and differential patterns, some unexpected, regarding comparisons across groups and across cohorts. CONCLUSIONS The descriptive findings form the basis for a clearer understanding of fertility and marriage patterns in different population subgroups in Israel. In addition, the reported results suggest many questions for future research, which are outlined in the paper.

  7. Characterization of stress induced by copper and zinc on cucumber (Cucumis sativus L.) seedlings by means of molecular and population parameters.

    Science.gov (United States)

    Soydam Aydin, Semra; Gökçe, Esra; Büyük, Ilker; Aras, Sümer

    2012-07-04

    Contamination of plants with heavy metals could result in damage in DNA, such as mutations and cross-links with proteins. These altered DNA profiles may become visible in changes such as the appearance of a new band, or loss of an existing band, in the random amplified polymorphic DNA (RAPD) assay. In this study, various concentrations of copper and zinc salts were applied to cucumber seedlings during germination. Results displayed abnormalities in germination and also changes in root elongation, dry weight and total soluble protein level. All treatment concentrations (40, 80, 160, 240, 320, and 640mg/L) used in the study caused a decrease/delay in germination of the cucumbers to different extents. Inhibition or activation of root elongation was considered to be the first effect of metal toxicity in the tested plants. Application of the metal salts and the combined solutions on cucumber (Cucumis sativus L.) seedlings revealed similar consequences for total soluble protein level, dry weight and ultimately in inhibitory rates as well. The data obtained from RAPD band-profiles and genomic template stability (GTS) showed results that were consistent with the population parameters. In this regard, we conclude that molecular marker assays can be applied in combination with population parameters to measure genotoxic effects of heavy metals on plants. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. What Does the Mean Mean?

    Science.gov (United States)

    Watier, Nicholas N.; Lamontagne, Claude; Chartier, Sylvain

    2011-01-01

    The arithmetic mean is a fundamental statistical concept. Unfortunately, social science students rarely develop an intuitive understanding of the mean and rely on the formula to describe or define it. According to constructivist pedagogy, educators that have access to a variety of conceptualizations of a particular concept are better equipped to…

  9. Default Meanings

    Institute of Scientific and Technical Information of China (English)

    K. M. Jaszczolt

    2006-01-01

    In this paper I present some aspects of the controversy surrounding the semantics/pragmatics boundary and offer a possible solution in the form of Default Semantics. First, I present a brief introduction to Paul Grice's approach to meaning as intentional communication. Next, I address the problem of the unit of which truth conditions should be predicated, assuming after Grice that the most successful approach to meaning has to make use of truth conditions.Further, I extend the discussion to some aspects of neo-Gricean pragmatics, most notably the issue of pragmatic processing that contributes to the truth-conditional representation and the proposed shortcuts through this processing in the form of default meanings. In the main part, I present the theory of Default Semantics ( Jaszczolt 2005a) , assess some arguments in favour of such an interactive theory of meaning that combines information from various sources, and address the issue of compositionality of meaning so conceived. In the final part, I apply the theory of Default Semantics to expressions with future-time reference in English in order to demonstrate the advantages of a framework that combines various types of information about utterance meaning in one, merged semantic representation. The main advantage turns out to be, in this domain, the unified treatment of all expressions with future-time reference.

  10. Intonational meaning.

    Science.gov (United States)

    Prieto, Pilar

    2015-01-01

    Traditionally, prosodic studies have focused on the study of intonational form and the study of intonational meaning has been relatively neglected. Similarly, the fields of semantics and pragmatics have paid little attention to the pragmatic uses of intonation. As a result, there is no firm agreement within the linguistic community on how to integrate the analysis of intonational meaning across languages into a unified prosodic, semantic, and pragmatic approach. This article provides an overview of the literature on intonational meaning, describing the recent advances made in the fields of prosody, semantics/pragmatics, and syntax. Several theoretical approaches to explaining the semantics and pragmatics of intonation are presented. A common feature to most frameworks is that intonation (1) should be regarded as an integral part of linguistic grammar; and (2) typically encodes meanings related to the modal aspect of propositions. However, features such as compositionality, duality of structure, and context-dependency are still hotly debated issues. These features will be discussed from different theoretical perspectives, and we will identify potential advances related to the full integration of intonational meaning into dynamic and multidimensional models of meaning.

  11. Comparação das comunidades de Entomobryidae e Isotomidae (Collembola entre plantio direto em três níveis de fertilidade, plantio convencional e um ecossistema natural (campo nativo em Ponta Grossa, Paraná, Brasil Comparison of the comniunitics of Entomobryidae and Isotomidae (Collembola among no-tillage in three levels of fertility, conventional tillage and a natural ecosystem (native grassland in Ponta Grossa, Paraná, Brazil

    Directory of Open Access Journals (Sweden)

    Klaus Dieter Sautter

    1999-03-01

    Full Text Available This work had as objective to compare the communities of Entomobryidae and Isotomidae (Collembola among no-tillage in three fertility levels, conventional tillage and a natural ecosystem (native grassland. In the no-tillage in low fertility and medium fertility Entomobryidae and Isotomidae had populational picks in the winter and in the summer. In the no-tillage in area of high fertility, there was a populational pick for both families in the summer. In relation to the conventional tillage, Entomobryidae had a populational pick in the winter, and Isotomidae in the winter and in the summer. In the natural ecosystem Entomobryidae presented populational picks in the winter and in the summer and Isotomidae had regular populational fluctuation along the period of the experiment. The final mean density of Entomobryidae was larger in the natural ecosystem, proceeded by the treatments of no-tillage and finally, for the conventional tillage. In relation to Isotomidae, the no-tillage in area of low fertility was superior, coming the conventional tillage soon after, the no-tillage in médium and high fertility, and, finally, the natural ecosystem.

  12. COPE-ICD: A randomised clinical trial studying the effects and meaning of a comprehensive rehabilitation programme for ICD recipients -design, intervention and population

    Directory of Open Access Journals (Sweden)

    Pedersen Birthe D

    2011-06-01

    Full Text Available Abstract Background Growing evidence exists that living with an ICD can lead to fear and avoidance behaviour including the avoidance of physical activity. It has been suggested that psychological stress can increase the risk of shock and predict death. Small studies have indicated a beneficial effect arising from exercise training and psychological intervention, therefore a large-scale rehabilitation programme was set up. Methods/Design A mixed methods embedded experimental design was chosen to include both quantitative and qualitative measures. A randomised clinical trial is its primary component. 196 patients (power-calculated were block randomised to either a control group or intervention group at a single centre. The intervention consists of a 1-year psycho-educational component provided by two nurses and a 12-week exercise training component provided by two physiotherapists. Our hypothesis is that the COPE-ICD programme will reduce avoidance behaviour, sexual dysfunction and increase quality of life, increase physical capability, reduce the number of treatment-demanding arrhythmias, reduce mortality and acute re-hospitalisation, reduce sickness leading to absence from work and be cost-effective. A blinded investigator will perform all physical tests and data collection. Discussion Most participants are men (79% with a mean age of 58 (range 20-85. Most ICD implantations are on primary prophylactic indication (66%. 44% is NYHA II. Mean walk capacity (6MWT is 417 m. Mean perception of General Health (SF-36 is PCS 42.6 and MCS 47.1. A large-scale ICD rehabilitation trial including psycho-educational intervention and exercise training has been initiated and will report findings starting in 2011. Trial Registration ClinicalTrials.gov: NCT00569478

  13. Contextual Meaning and Word Meaning

    Institute of Scientific and Technical Information of China (English)

    Istvan Kecskes

    2006-01-01

    The paper has three goals: 1 ) Explain the role of context and word in meaning construction and comprehension. 2) Present a model that can explain meaning generated by both monolingual and multilingual meaning construction systems. 3) Discuss how the model can be applied to explain major issues in pragmatics.Pragmatics is understood here in a narrow sense as defined by Sperber & Noveck: "...pragmatics is the study of how linguistic properties and contextual factors interact in the interpretation of utterances" ( Sperber & Noveck 2004:1 ). It is argued that world knowledge is available to interlocutors in two forms: as encapsulated in lexical items based on prior encounters and experience (conventionalized cognitive context), and as provided by the actual situational context framed by the situation in which the interaction takes place. Meaning formally expressed in the linguistic interactional context is created on-the-spot, and is the result of the interaction of the two sides of world knowledge and the actual situational context.The paper makes three claims: First, supremacy of context is not unconditional in language processing. Second,salient meaning rather than literal meaning of lexical units plays a central role in comprehension. Third, intercultural communication differs from intracultural communication in the conceptual content of conventionalized cognitive contexts rather than in communicative means.

  14. Suppression of fertility in adult dogs.

    Science.gov (United States)

    Maenhoudt, C; Santos, N R; Fontbonne, A

    2014-06-01

    Unfortunately, the overpopulation of dogs is still a problem in the majority of countries and even though surgical methods of sterilization, the most traditional and commonly used technique, have been intensively performed, the impact on the dog population is negligible. The neutering of companion animals as ovariohysterectomy (spaying) or orchidectomy (castration) has its limitations because of the cost, the need of a surgical environment and the risk of surgical and/or anaesthetical complications (ACCD 2009). In fact, surgical castration has been banished in some northern European countries and has limited acceptance in other countries. In a survey performed in Sao Paulo, Brazil, 56.5% of the owners of adopted shelter dogs were against the surgical procedure for different reasons (Soto et al. 2005). Currently, the options for contraception, defined as suppression of fertility are based on hormonal treatment. The treatments can be divided into analogues of gonadotropin releasing hormone (GnRH), progestins and androgens. Other possibilities of contraception are via the immunological system with vaccinations against GnRH, the luteinizing hormone (LH) receptor and the zona pellucida proteins. Finally, there is also the intra-epididymal or intratesticular injection of sclerosing substances in dogs. Mechanical devices to disrupt fertility are not used anymore due to the side effects. Suppression of fertility in adult dogs will be reviewed in order of use and possible impact on the dog population. © 2014 Blackwell Verlag GmbH.

  15. [Impact of backward sexual viewpoints on population development].

    Science.gov (United States)

    Wang, B

    1991-04-01

    In the development of human society, the reproductive function was considered the sole purpose of sexual activities. Any other purposes were deemed abnormal or deviant. The prevalence of that viewpoint reflected the needs during the transformation from hunting to farming as major means of production of the society and the needs for large populations under the socioeconomic conditions of rural society. With the low level of productivity in a family-oriented economy, further development depended on the number of labor hands in the family. The wars for extension of territory and for survival need a constant supply of soldiers. Under such circumstances, the need for large populations implied the importance of fertility behavior in sexual relations. In the rural farming societies, fertility was important in strengthening and developing the family wealth, status, and family structure. Blood relations were emphasized in rural society for family inheritance, for expansion of family influence, and for old age support. The rapid decline of fertility in Europe at the beginning of this century was proposed by some Chinese scholars as the result of their citizens pursuing individual happiness including in sexual relations. The use of contraceptives prevented couples from being overburdened with children. These concepts on sexual relations facilitated the decline of fertility. The necessary social and economic conditions and advances in technology are already present for the changes of the traditional concepts toward sexual relations. The united efforts of social agencies in promoting these changes will be an efficient ensure in regulating the speed of population growth.

  16. Shit and piss : An environmental history of the meaning and management of human excrement in densely populated areas and urban regions, with a focus on agriculture and public health issues

    OpenAIRE

    Steinig, Wenzel

    2016-01-01

    This thesis analyses individual and societal relations to human excrement by looking at historical and contemporary examples of symbolics and management systems of human shit and piss. It furthermore connects urban culture to a particular type of perception of the meaning of human waste. End-of-pipe, large scale sewerage solutions for densely populated areas and cities are analysed for their historical origins and contemporary ramifications, and contrasted with examples of classical, mediaeva...

  17. Paternal Urinary Concentrations of Parabens and Other Phenols in Relation to Reproductive Outcomes among Couples from a Fertility Clinic

    Science.gov (United States)

    Dodge, Laura E.; Williams, Paige L.; Williams, Michelle A.; Missmer, Stacey A.; Toth, Thomas L.; Calafat, Antonia M.

    2015-01-01

    Background Human exposure to phenols, including bisphenol A and parabens, is widespread. Evidence suggests that paternal exposure to environmental chemicals may adversely affect reproductive outcomes. Objectives We evaluated associations of paternal phenol urinary concentrations with fertilization rate, embryo quality, implantation, and live birth. Methods Male–female couples who underwent in vitro fertilization (IVF) and/or intrauterine insemination (IUI) cycles in a prospective study of environmental determinants of fertility and pregnancy outcomes were included. The geometric mean of males’ specific gravity–adjusted urinary phenol concentrations measured before females’ cycle was quantified. Associations between male urinary phenol concentrations and fertilization rate, embryo quality, implantation, and live birth were investigated using generalized linear mixed models to account for multiple cycles per couple. Results Couples (n = 218) underwent 195 IUI and 211 IVF cycles. Paternal phenol concentrations were not associated with fertilization or live birth following IVF. In adjusted models, compared with the lowest quartile of methyl paraben, paternal concentrations in the second quartile were associated with decreased odds of live birth following IUI (adjusted odds ratio = 0.19; 95% CI: 0.04, 0.82). Conclusions To our knowledge, these are some of the first data on the association of paternal urinary phenol concentrations with reproduction and pregnancy outcomes. Although these results do not preclude possible adverse effects of paternal paraben exposures on such outcomes, given the modest sample size, further understanding could result from confirmation using a larger and more diverse population. Citation Dodge LE, Williams PL, Williams MA, Missmer SA, Toth TL, Calafat AM, Hauser R. 2015. Paternal urinary concentrations of parabens and other phenols in relation to reproductive outcomes among couples from a fertility clinic. Environ Health Perspect 123

  18. Fertility of Czech Females Could Be Lower than Expected: Trends in Future Development of Age-Specific Fertility Rates up to the Year 2050

    Directory of Open Access Journals (Sweden)

    Ondřej Šimpach

    2015-03-01

    Full Text Available Fertility is an essential aspect of reproduction or population replacement of each country. The challenge for demographers is to model fertility and also to estimate its potential future level for the purposes of population projections. In the case of the Czech Republic we have the population projections provided by the Czech Statistical Office (CZSO with overlooking of the total fertility rate in low, medium and high variant. These estimates despite being based on expert judgments, seem to be too positive compared to the past development of the time series of age-specific fertility rates. The aim of this paper is to assess the situation of fertility in the Czech Republic, to analyse the past development of the time series of age-specific fertility rates using one-dimensional Box-Jenkins models and multidimensional stochastic Lee-Carter approach. Together with found trend in time series and principal components estimated by Lee-Carter’s model a forecasts of age-specific fertility rates up to the year 2050 is constructed. Th ese rates are lower than those provided by CZSO in its three variants of the Czech Republic’s population projection, and therefore we discuss the causes at the end of the paper. We would like to point out that the potential future development of Czech females fertility could be lower than which are currently expected.

  19. Environmental Impact Research Program. The Use of Fertilizer To Enhance Transplants of the Seagrasses Zostera marina and Halodule wrightii.

    Science.gov (United States)

    1987-08-01

    spring 1985 with Zostera and in late spring 1985 with Halodule. The fertilizer types were applied in 3 dose levels (10, 90, and 170 g/planting unit...Replicate treatments, including fertilized control plantings, were randomly assigned locations on each of the three sites. Release of fertilizer , as well...Phosphorus did not release in any of the experiments. A significant difference was found in population growth between pooled balanced and pooled unbalanced fertilizer treatments in the fall Zostera experiment only.

  20. [Fertility transition in Brazil. Causes and consequences].

    Science.gov (United States)

    Carvalho, J A; Wong, L R

    1992-12-01

    This work examines the determinants and most important consequences of the Brazilian fertility decline. Brazil's total fertility rate declined from 6.2 in 1940 to around 3.5 in 1985. the decline began in the 1960s and amounted to 45% in about 20 years. The most rapid drop began in the late 1970s, with much of it concentrated in 2 specific periods: 1970-75 and 1980-85. The early period coincided with Brazil's so-called "Economic Miracle", a period of rapid growth accompanied however by deteriorating living conditions for the poorest population sectors. The second period coincided with the international economic crisis of the early 1980s, which was felt more strongly in Brazil than elsewhere in Latin America because of Brazil's greater degree of industrialization and closer integration into the world economy. Most of the fertility decline has been accomplished by use of just two contraceptive methods, oral contraceptives and sterilization, which together account for around 85% of contraceptive usage throughout Brazil. The third most common method, rhythm, accounts for just 6%. No reliable data on abortion are available, but it appears to be a common practice equally accessible to all socioeconomic strata despite greater associated health risks for poorer women. Brazil's fertility transition appears to have been a response to the process of proletarianization and urbanization underway in the country as well as to particular circumstances in the country. The most evident and immediate consequence of the continuous fertility decline over more than 20 years is the change in the age structure of the population. The proportions of children under 5 will decline from 14.4% in 1980 to 9.2% in 2010. The proportion aged 5-14 will decline from 24.5% to 17.4%, while the proportion aged 65 and over will increase from 4.0% to 5.6%. Brazil's recent demographic changes are scarcely reflected in development plans and political and social projects. There is almost no mention of the new

  1. Immigrant fertility in Sweden, 2000-2011: A descriptive note

    Directory of Open Access Journals (Sweden)

    Lotta Persson

    2014-03-01

    Full Text Available Background: Modern Scandinavian population registers provide excellent data sources that allow a user to quickly gain an impression of the level of fertility and its structure across subpopulations. This may also allow the analyst to check a feature of the much-cited disruption hypothesis, at least in part. Objective: The purpose of this note is to exploit this potential to give an overview of the structure of recent total fertility after immigration to Sweden from various groups of sending countries, separately for males and females. In the process we demonstrate to what extent the post-migration fertility compensation which is part of the fertility disruption hypothesis is fulfilled in our study population. Due to the nature of our data we have refrained from studying fertility before migration. Methods: Based on data from a combination of two Swedish administrative registers (the Historic Population Register and the Multi-Generation Register that cover both men and women in the entire population for the years 2000-2011, we compute and plot TFR-like age-cumulated fertility levels, specific for years since immigration, for six groups of sending countries, separately for men and women. Results: We find that the post-migration fertility compensation specified as part of the fertility disruption hypothesis is visibly confirmed in our Swedish study population for female European immigrants from non-EU countries and for female immigrants from non-European countries with a low or medium UN Human Development Index, but not so for other female immigrants, i.e. not for those who come from a Nordic country or from a non-Nordic EU country, and not for female immigrants from a non-European country with a high Human Development Index, including the United States. We find mild but less conclusive evidence for the same feature for males. Conclusions: This shows that at least as far as post-migration fertility compensation is concerned, the disruption

  2. Temporal Trends in Fertility Rates

    DEFF Research Database (Denmark)

    Jensen, Martin Blomberg; Priskorn, Lærke; Jensen, Tina Kold

    2015-01-01

    to determine total and age specific fertility rates. RESULTS: Total fertility rate (TFR) decreased from 4.1 to 1.8 children per woman and age specific fertility also decreased from 1901 to 2014. Women aged 30-34, 35-39 or 40-44 years in the first decade of the 20th century had higher fertility rates than......OBJECTIVE: Increasing age at first childbirth has been suggested to increase the risk for infertility. Our objective is to determine whether women above thirty years of age historically have been able to sustain fertility rates above replacement level. DESIGN: A descriptive nationwide Danish study...... for 10% of TFR in 1901 compared with 4% in 2014 despite usage of assisted reproduction. CONCLUSION: This nationwide study shows that women above 30 years of age historically have been able to sustain fertility rates above replacement level. This implies that other factors besides age are strong...

  3. Radiological investigation of phosphate fertilizers: Leaching studies.

    Science.gov (United States)

    Hegedűs, Miklós; Tóth-Bodrogi, Edit; Németh, Szabolcs; Somlai, János; Kovács, Tibor

    2017-07-01

    The raw materials of the phosphate fertilizer industry are the various apatite minerals. Some of these have high levels of natural radionuclides, and thus phosphate fertilizers contain significant amounts of U-238, K-40 and Ra-226. These can leach out of the fertilizers used in large quantities for resupplying essential nutrients in the soil and can then enter the food chain through plants, thereby increasing the internal dose of the affected population. In the current study, the radiological risk of eight commercially available phosphate fertilizers (superphosphate, NPK, PK) and their leaching behaviours were investigated using different techniques (gamma and alpha spectrometry), and the dose contributions of using these fertilizers were estimated. To characterize the leaching behaviour, two leaching procedures were applied and compared -the MSZ 21470-50 (Hungarian standard) and the Tessier five-step sequential extraction method. Based on the evaluation of the gamma-spectra, it is found that the level of Th-232 in the samples was low (max.7 ± 6 Bq kg(-1)), the average Ra-226 activity concentration was 309 ± 39 Bq kg(-1) (min. 10 ± 8 Bq kg(-1), max. 570 ± 46 Bq kg(-1)), while the K-40 concentrations (average 3139 ± 188 Bq kg(-1), min. 51 ± 36 Bq kg(-1)) could be as high as 7057 ± 427 Bq kg(-1). The high K-40 can be explained by reference to the composition of the investigated fertilizers (NPK, PK). U concentrations were between 15 and 361 Bq kg(-1), with the average of 254 Bq kg(-1), measured using alpha spectrometry. The good correlation between P2O5 content and radioactivity reported previously is not found in our data. The leaching studies reveal that the mobility of the fertilizer's uranium content is greatly influenced by the parameters of the leaching methods. The availability of U to water ranged between 3 and 28 m/m%, while the Lakanen-Erviö solution mobilized between 10 and 100% of the U content. Copyright © 2016

  4. Austria: Persistent low fertility since the mid-1980s

    Directory of Open Access Journals (Sweden)

    Henriette Engelhardt

    2008-07-01

    Full Text Available This chapter offers an in-depth analysis of fertility in Austria, a country which has experienced a low and relatively stable fertility level and a gradual postponement of childbearing since the mid-1980s. We begin by summarising Austrian population trends in the post-World War II period and highlighting recent relatively high migration levels. We outline the long history of sub-replacement fertility and high childlessness in Austria and look in detail at recent parity-specific developments, trends in family size, delayed childbearing and persistent fertility differences by education level, country of origin and religious affiliation. The chapter then summarises main trends in family-related behaviour, including the changing patterns of leaving parental home, the rise in cohabitation, the decline in marriage and the rise of divorce and the diversity in non-marital childbearing, which has a long tradition in many parts of the country. We discuss the development of family policies in Austria and their relationship to fertility during the past decades. Social policies in Austria provide only a limited support for a reconciliation of childrearing and employment among mothers with children below the age of three. A combination of one of the highest family spending rates among the OECD countries and the low fertility rates indicate that structural constraints (such as the availability of childcare constitute part of the explanation of low fertility.

  5. Preserving fertility in young patients with lymphoma: an overview

    Directory of Open Access Journals (Sweden)

    Patel B

    2014-12-01

    Full Text Available Bansari Patel, Brooke V Rossi Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, Case Western Reserve University, Cleveland, OH, USA Abstract: Fertility preservation affords patients the ability to reproduce after the initial diagnosis and management of such malignancies as Hodgkin's and non-Hodgkin's lymphoma. Certain chemotherapy regimens and pelvic radiotherapy confer a high-risk of subsequent gonadal compromise in both males and females. Fortunately, early counseling and initiation of fertility-preservation strategies promptly after diagnosis enable patients to maintain hope for future reproduction. Well-established methods for fertility preservation include embryo and oocyte cryopreservation in females and sperm cryopreservation in males. These methods enable patients to utilize assisted reproductive technologies, including in vitro fertilization, at the time of desired childbearing in order to ensure genetic offspring. As most of these modalities are not feasible in some patient populations, including prepubescent patients, newer methods of fertility preservation must be created to ensure the ability to produce genetic offspring in lymphoma patients. This review provides insights into the impact of gonadotoxic treatment on ovarian and testicular function, and highlights current modalities in fertility preservation in both males and females. Keywords: fertility preservation, lymphoma, ART, egg freezing

  6. Probabilistic Projections of the Total Fertility Rate for All Countries

    Science.gov (United States)

    Raftery, Adrian E.; Gerland, Patrick; Clark, Samuel J.; Pelletier, François; Buettner, Thomas; Heilig, Gerhard K.

    2012-01-01

    We describe a Bayesian projection model to produce country-specific projections of the total fertility rate (TFR) for all countries. The model decomposes the evolution of TFR into three phases: pre-transition high fertility, the fertility transition, and post-transition low fertility. The model for the fertility decline builds on the United Nations Population Division’s current deterministic projection methodology, which assumes that fertility will eventually fall below replacement level. It models the decline in TFR as the sum of two logistic functions that depend on the current TFR level, and a random term. A Bayesian hierarchical model is used to project future TFR based on both the country’s TFR history and the pattern of all countries. It is estimated from United Nations estimates of past TFR in all countries using a Markov chain Monte Carlo algorithm. The post-transition low fertility phase is modeled using an autoregressive model, in which long-term TFR projections converge toward and oscillate around replacement level. The method is evaluated using out-of-sample projections for the period since 1980 and the period since 1995, and is found to be well calibrated. PMID:21748544

  7. Biodegradation of aliphatic vs. aromatic hydrocarbons in fertilized arctic soils

    Science.gov (United States)

    Braddock, J.F.

    1999-01-01

    A study was carried out to test a simple bioremediation treatment strategy in the Arctic and analyze the influence of fertilization the degradation of aliphatic and aromatic hydrocarbons, e.g., pristine, n-tetradecane, n-pentadecane, 2-methylnaphthalene, naphthalene, and acenaphthalene. The site was a coarse sand pad that once supported fuel storage tanks. Diesel-range organics concentrations were 250-860 mg/kg soil at the beginning of the study. Replicate field plots treated with fertilizer yielded final concentrations of 0, 50, 100, or 200 mg N/kg soil. Soil pH and soil-water potentials decreased due to fertilizer application. The addition of fertilizer considerably increased soil respiration potentials, but not the populations of microorganisms measured. Fertilizer addition also led to ??? 50% loss of measured aliphatic and aromatic hydrocarbons in surface and subsurface soils. For fertilized plots, hydrocarbon loss was not associated with the quantity of fertilizer added. Losses of aliphatic hydrocarbons were ascribed to biotic processes, while losses of aromatic hydrocarbons were due to biotic and abiotic processes.

  8. Fertility as a process of social exchange

    Directory of Open Access Journals (Sweden)

    Patrick Heady

    2007-12-01

    Full Text Available By marrying and raising children, parents participate in a system of gift-exchange in which the gifts in question are human lives, and the parties to the exchange are the kinship groups recognised in the society concerned. Fertility reflects the attitudes of prospective parents to their place in the existing system of reproductive exchange, and the relationships of cooperation and authority which it implies - as well as their confidence in the system's continuing viability. It is shown that this view is compatible with earlier ideas about self-regulating population systems - and that changing economic circumstances are an important source of discrepancy between existing exchange systems and the attitudes and expectations of prospective parents. The discussion is developed with reference to data on European societies, including a case-study from the Alps, and concludes with an assessment of the relevance of the anthropological theory of gift exchange to contemporary fertility patterns in Europe and beyond.

  9. Fertility and age

    Directory of Open Access Journals (Sweden)

    Korula George

    2010-01-01

    Full Text Available The changing social scenario together with economic growth and an increase in job opportunities has to a great extent reduced gender inequality and has resulted in more and more older women seeking help from infertility clinics. Fertility and aging have always been closely linked and the age of the female partner remains the single most important factor in predicting success with treatment. Although tests for the ovarian reserve are an important informative tool and are helpful in selecting treatment options, they are poor predictors of the outcome.

  10. Recuperação populacional e fecundidade dos Kamaiurá, povo Tupi do Alto Xingu, Brasil Central, 1970-2003 Population recovery and fertility Among the Kamaiurá, Tupi people of the Alto Xingu, Central Brazil, 1970-2003

    Directory of Open Access Journals (Sweden)

    Heloisa Pagliaro

    2007-08-01

    well as moderate fertility levels were responsible for the stability trend of the population. The average population growth between 1967 and 2003 was 3.5%. Total fertility rates increased from 5.7 to 6.2 births per woman, between 1970 and 2003, reaching their highest level in 1980 (6.6. Since the 1990s there has been an ageing of the reproductive patterns, with the decrease of fertility levels among women up to 24 years of age, and an increase among women in the other age groups. The average age at first birth increased from 16.2 to 18.8 years between 1970-2003; the proportion of single women older than 15 years also increased: from 6.3% in 1971 to 26% in 2003; the inter-birth intervals varied between 30.3 and 36 months. The increase in the Kamaiurá's fertility rate was favored by the decrease in general and infant mortality rates, but the Kamaiurá did not abandon their traditional fertility controls, which has allowed a rational and balanced population growth.

  11. Altura de planta e componentes do rendimento do feijoeiro em função de população de plantas, adubação e calagem Common bean plant height and primary yield components affected by plant population, fertilization and liming

    Directory of Open Access Journals (Sweden)

    Antonio Barbara de Souza

    2003-12-01

    Full Text Available Com o objetivo de investigar os efeitos de populações de plantas e níveis de adubação e calagem sobre a altura e os componentes do rendimento de grãos do feijoeiro (Phaseolus vulgaris L. em um solo Podizólico Vermelho Amarelo distrófico, de baixa fertilidade natural, foram conduzidos três experimentos de campo em Lavras - MG. Nos dois primeiros, utilizaram-se a cv. Pérola e delineamento experimental em blocos casualizados, com quatro repetições, no arranjo fatorial 4x4, envolvendo quatro populações: 120, 180, 240 e 300 mil plantas.ha-1 e quatro níveis de adubação e calagem: 0, 1/3, 2/3 e 3/3 das doses de fertilizantes e calcário recomendadas para o nível 2 de tecnologia pela Comissão de Fertilidade do Solo do Estado de Minas Gerais. No terceiro ensaio, o arranjo fatorial foi 2x4x4, envolvendo duas cultivares, Pérola e Carioca, quatro populações, 100, 200, 300 e 400 mil plantas.ha-1; e quatro níveis de adubação e calagem 0, 1/2, 2/2 e 3/2 das doses. O incremento da população de plantas reduziu a altura e o número de vagens por planta e o incremento dos níveis de adubação e calagem elevou a altura, o número de vagens por planta, o número de grãos por vagem e a massa média do grão.With a view to defining the plant density and level of fertilization and liming for the bean crop ( Phaseolus vulgaris L. in a natural low fertility soil (distrophic Red Yellow Podzolic, three field experiments were carried out in Lavras - MG. In the two first experiments the cultivar Pérola was utilized and the randomized block experimental design, with four replications and 4x4 factorial arrangement, involving four populations (120, 180, 240 and 300 thousand plants.ha-1 and four levels of fertilization and liming (0, 1/3, 2/3 and 3/3 of the recommended doses of fertilizers and limistone for the level 2 of technology by the Comissão de Fertilidade do Solo do Estado de Minas Gerais was adopted. In the third trial, the factorial

  12. WILL FERTILITY REBOUND IN JAPAN

    OpenAIRE

    Creina Day

    2012-01-01

    Fertility and per capita income are now positively associated across most high income OECD countries. Low fertility and a gender wage gap persist in Japan. This paper presents an original model where endogenous increases in childcare prices and gender equity in capital allocation play important roles in the effect of per capita income growth and rising female relative wages on fertility. Results suggest Japan has cause for optimism. Economic growth will raise female relative wages where capit...

  13. Evaluate Potential Means of Rebuilding Sturgeon Populations in the Snake River between Lower Granite and Hells Canyon Dams, 1998 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Everett, Scott R.; Tuell, Michael A. (Nez Perce Tribe, Department of Fisheries Resource Management, Lapwai, ID)

    2002-03-01

    In 1998 white sturgeon (Acipenser transmontanus) were captured, marked, and population data were collected in the Snake River between Lower Granite Dam and the mouth of the Salmon River. A total of 13,785 hours of setline effort and 389 hours of hook-and-line effort was employed in 1998. Of the 278 white sturgeon captured in the Snake River, 238 were marked for future identification. Three sturgeon were captured in the Salmon River and none were captured in the Clearwater River. Since 1997, 6.9% of the tagged fish have been recovered. Movement of recaptured white sturgeon ranged from 98.5 kilometers downstream to 60.7 kilometers upstream, however, less than 25% of the fish moved more than 16 kilometers (10 miles). In the Snake River, white sturgeon ranged in total length from 51.5 cm to 286 cm and averaged 118.9 cm. Differences were detected in the length frequency distributions of sturgeon in Lower Granite Reservoir and the free-flowing Snake River (Chi-Square test, P < 0.05). In addition, the proportion of white sturgeon greater than 92 cm (total length) in the free-flowing Snake River has shown an increase of 37% since the 1970's. Analysis of the length-weight relationship indicated that white sturgeon in Lower Granite Reservoir were slightly larger than white sturgeon in the free-flowing Snake River.

  14. 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

  15. A Re-Interpretation of the 'Two-child Norm' in Post-Transitional Demographic Systems: Fertility Intentions in Taiwan.

    Directory of Open Access Journals (Sweden)

    Stuart Basten

    Full Text Available Taiwan currently has one of the lowest fertility rates in the world, leading to projections of rapid population ageing and decline. In common with other territories in Pacific Asia, policies designed to support childbearing have recently been introduced. Some optimism for the future success of these policies has been drawn from the fact that the 'ideal' number of children stated in Taiwanese surveys is over two. In this way, Taiwan appears to fit the 'two-child norm' model identified for Europe and North America. Furthermore, this feature has led commentators to state that Taiwan is not in a 'low fertility trap'-where positive feedback mechanisms emanating from the normalisation of small families, slow economic growth and ageing/declining population mean attempts to increase fertility become ever less likely to succeed. Using a recent national representative survey, and arguing that 'intentions' are a more reliable guide to understanding the circumstances of family formation, this paper explores fertility intentions in Taiwan with a special focus on women at parity one and parity two. This will form the first full-length examination of fertility intentions in Taiwan published in English and one of the few studies of Pacific Asia that reports a micro-level analysis. We argue that using intentions should provide a better 'barometer' of attitudes towards childbearing in Taiwan, and that through micro-level analysis, we can better identify the predictors of intentions that could, in turn, provide useful clues both for projections as well as shaping policy responses. While we found some evidence for a 'two-child norm' among childless women, this could be an unrealistic ideal. This is supported by the fact that a majority of women with one child do not intend to have another.

  16. A Re-Interpretation of the 'Two-child Norm' in Post-Transitional Demographic Systems: Fertility Intentions in Taiwan.

    Science.gov (United States)

    Basten, Stuart; Verropoulou, Georgia

    2015-01-01

    Taiwan currently has one of the lowest fertility rates in the world, leading to projections of rapid population ageing and decline. In common with other territories in Pacific Asia, policies designed to support childbearing have recently been introduced. Some optimism for the future success of these policies has been drawn from the fact that the 'ideal' number of children stated in Taiwanese surveys is over two. In this way, Taiwan appears to fit the 'two-child norm' model identified for Europe and North America. Furthermore, this feature has led commentators to state that Taiwan is not in a 'low fertility trap'-where positive feedback mechanisms emanating from the normalisation of small families, slow economic growth and ageing/declining population mean attempts to increase fertility become ever less likely to succeed. Using a recent national representative survey, and arguing that 'intentions' are a more reliable guide to understanding the circumstances of family formation, this paper explores fertility intentions in Taiwan with a special focus on women at parity one and parity two. This will form the first full-length examination of fertility intentions in Taiwan published in English and one of the few studies of Pacific Asia that reports a micro-level analysis. We argue that using intentions should provide a better 'barometer' of attitudes towards childbearing in Taiwan, and that through micro-level analysis, we can better identify the predictors of intentions that could, in turn, provide useful clues both for projections as well as shaping policy responses. While we found some evidence for a 'two-child norm' among childless women, this could be an unrealistic ideal. This is supported by the fact that a majority of women with one child do not intend to have another.

  17. Dimensions of Philippine population.

    Science.gov (United States)

    1980-01-01

    Major findings of a 2 1/2 year research program on Philippine population are presented. The population situation is described with respect to fertility, mortality, life expectancy, migration, labor force, and family formation. Policy recommendations addressing problems in each of these areas are made.

  18. Understanding Population Projections.

    Science.gov (United States)

    Haub, Carl

    1987-01-01

    Population projections are "what if" computational exercises. Given selected assumptions about future trends in fertility, mortality, and migration, population trends can be projected. Government and business planners need this information, and they also require enough time to put facilities in place to meet future needs. Everyone benefits from a…

  19. Fertility estimation: a review of past experience and future prospects.

    Science.gov (United States)

    Foote, Robert H

    2003-01-15

    Fertility has many components and stages which require that males and females be functionally capable of carrying out all critical stages if each generational reproductive cycle is to be completed. To accomplish this, the male must produce and ejaculate normal fertile sperm. The female must produce, store and ovulate normal fertilizable oocytes. Furthermore, the female must provide a reproductive system compatible with sperm transport, capacitation, and fertilization of the oocytes, embryo and fetal development, and finally birth of healthy young. Reproductive success or failure at several of these points can be estimated quantitatively on a population basis, and in a few situations on an individual basis. It is important that fertility estimates be determined accurately and with precision to be most useful to researchers and managers of animal enterprises. Many studies have underestimated the biological relationship of fertility to other traits because the estimates lacked precision. Many in vitro manipulations of sperm in artificial insemination, of gametes in various assisted reproductive technologies, and of embryos in embryo transfer are utilized in animal breeding programs. Accurate estimation of reproductive efficiency of these in vitro procedures also is important. Conditions surrounding different sets of fertility estimates almost certainly will be different. These conditions should be described as precisely as possible, and appropriate controls included in all experiments. When possible, experiments should be replicated over time and place to determine the repeatability of the various criteria used to estimate fertility and reproductive efficiency. Advances in genomic information and molecular biology should facilitate characterizing more fully inherent potential fertility of animals at birth. In vitro tests will improve, and automated techniques will facilitate making multiple determinations possible on a large scale. Reliability of fertility estimates

  20. Distal determinants of fertility decline: Evidence from 640 Indian districts

    Directory of Open Access Journals (Sweden)

    Sanjay K. Mohanty

    2016-03-01

    Full Text Available Background: Districts in India exhibit enormous variation in the level of socioeconomic development and are at different stages of fertility transition. Though a large and growing body of literature has examined the proximate determinant of fertility at the state and individual levels, there are limited studies on distal determinants of fertility change in the districts (micro-regions of India. This is the first ever study to examine the association of fertility change with three key distal determinants, namely female literacy, under-five mortality, and poverty, over the last two decades in districts of India. Objective: To examine the association of female education, under-five mortality, and poverty in fertility reduction in the districts of India. Methods: Data from the census of India and large-scale population-based surveys are used. Difference-in-difference panel models are used to account for both initial conditions and contemporaneous changes in fertility reduction. Results: While one-third of the districts have reached below replacement level of fertility, under-five mortality and poverty level have reduced by half from the initial level and the female literacy level has almost doubled, suggesting a remarkable degree of convergence across all distal determinants but only limited evidence of convergence for fertility. The single largest predictor of fertility reductions in the districts of India was initial TFR (−0.83, followed by increase in female literacy (−0.76, the initial female literacy level (-0.43 and reduction in under-five mortality (-0.20. The effect of initial level of poverty on fertility reduction was 0.13, while that of reduction in poverty was −0.05. Given that the confidence intervals around both estimates are large, this suggests a rather limited role of poverty in fertility transition. Conclusions: Reduction in under-five mortality and female education explain the majority of the large fertility declines

  1. Behaviour of lactic acid bacteria populations in Pecorino di Carmasciano cheese samples submitted to environmental conditions prevailing in the gastrointestinal tract: evaluation by means of a polyphasic approach.

    Science.gov (United States)

    Ricciardi, Annamaria; Blaiotta, Giuseppe; Di Cerbo, Alessandro; Succi, Mariantonietta; Aponte, Maria

    2014-06-02

    The survival of the autochthonous microflora, of samples collected during Pecorino di Carmasciano cheese manufacturing, was evaluated along the passage through a model mimicking the gastro-intestinal tract. The aim was the selection of lactic acid bacteria potentially able to arrive alive and metabolically active to the colon. The dynamics of lactic microbiota, throughout simulated digestion of cheese samples, were evaluated by means of an approach PCR-DGGE-based. Dominant species after cheese digestion could be related to the Lactobacillus plantarum and Lactobacillus casei groups. Sixty-three strains, which survived to simulated gastro-intestinal transit, were further evaluated for technological features and tolerance to human digestion in several experimental conditions, according to routinely used protocols. Bacterial survival appeared to be, more than strain-specific, strongly affected by experimental conditions, i.e. some strains showed an acceptable survival when resuspended in skim milk but not in ewe milk and vice versa. Nevertheless according to data, one gram of fresh Pecorino di Carmasciano cheese may convey to human colon about the same amount of viable LAB of a probiotic drink. Although it cannot be assumed that lactobacilli introduced with Pecorino have beneficial effects on the host, the healthy impact of autochthonous lactic acid bacteria of naturally fermented food has a broad consensus in the current literature. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Effects of plant population and nitrogen fertilizer on yield and efficiency of maize-bean intercropping Efeito de população de plantas e adubação nitrogenada na produção e eficiência do consórcio milho-feijão

    Directory of Open Access Journals (Sweden)

    Luiz Balbino Morgado

    2003-11-01

    Full Text Available Nitrogen supply and plant population are basic parameters for cereal-legume intercropping. In order to study plant population and nitrogen fertilizer effects on yield and yield efficiency of maize-bean intercropping, a field experiment was established. Three bean plant populations and three nitrogen levels were used. Maize dry matter accumulation decreased with increases in bean plant population. Competitive effect of intercrop beans on maize yields was high at higher plant populations, being decreased by nitrogen fertilizer; application of 50 kg ha-1 N was very efficient in increasing maize cob yield. Intercropping significantly decreased harvest index of beans in all plant population and nitrogen fertilizer situations. The efficiency of intercropping, compared to sole cropping, was evidenced by the values obtained for Land Equivalent Ratio (LER for biomass, cob and pod yields that increased with increases in bean plant populations and nitrogen fertilizer levels.A disponibilidade de nitrogênio e a população de plantas são parâmetros básicos para o consórcio de gramíneas e leguminosas. Os efeitos de diferentes populações de plantas de feijão e níveis de nitrogênio na produção e eficiência do consórcio milho-feijão foram estudados em um experimento de campo. Foram usadas três populações de plantas de feijão e três níveis de nitrogênio. O acúmulo de matéria seca do milho durante o ciclo vegetativo decresceu à proporção que a população de feijão aumentou. O efeito competitivo do feijão na produção do milho consorciado, que se mostrou maior nas maiores populações de plantas, foi atenuado pela aplicação da adubação nitrogenada; a aplicação de 50 kg ha-1 de N foi muito eficiente no aumento da produção de espiga do milho. O consórcio diminuiu significativamente o índice de colheita do feijão em todas as populações de plantas e em todos os níveis de nitrogênio aplicados. A eficiência do cons

  3. Fertility and the changing female educational attainment in Croatia

    Directory of Open Access Journals (Sweden)

    Čipin Ivan

    2016-01-01

    Full Text Available This paper investigates the aggregate relationship between cohort fertility and female educational attainment in Croatia. Numerous demographic studies have examined the link between fertility and the level of education. However, newer research indicates that the field of education might also play a role when trying to explain fertility behavior. We contribute to existing literature on macro-level factors related to reproductive outcomes by considering both the level and field of education as possible sources of cohort fertility differentials. The main goal of the present study is to assess the effect of structural changes in educational attainment on cohort fertility decline by means of demographic decomposition techniques. Our analysis is based on detailed 2011 Census data, which provide information on the number of livebirths by mother’s year of birth, birth order, marital status and educational attainment (i.e. the level and field of education. The results of our decomposition analyses reveal the dominance of the structural effect in explaining the overall completed fertility decline in Croatia. We assumed that the changing distribution of women by field of education at least partially accounts for the observed patterns in completed fertility but found no strong evidence in support of the outlined hypothesis.

  4. Fertile ground? : soil fertility management and the African smallholder

    NARCIS (Netherlands)

    Misiko, M.

    2007-01-01

    Keywords: smallholder farmers, soil fertility, experimentation, "inconvenience", realist.The focus in this thesis is to form a view of how well soil fertility research performs within the ever shifting smallholder contexts. This study examined application of agro-ecological knowled

  5. Endoscopic Vasectomy of Male Feral Pigeons (Columba livia) as a Possible Method of Population Control.

    Science.gov (United States)

    Heiderich, Elisabeth; Schildger, Bernd; Lierz, Michael

    2015-03-01

    To evaluate whether single-entry endoscopic vasectomy of male feral pigeons (Columba livia) significantly reduced fertility and would potentially be valuable for control of feral pigeon populations, 252 male feral pigeons were caught in the city of Berne and endoscopically vasectomized. In this procedure, approximately 1 cm of the deferent duct was removed bilaterally. Rapid, uneventful recoveries occurred in 94% (237/252) of the pigeons, whereas 6% (15/252) died because of complications associated with the procedure, consisting of perforation of the ureter (9/15), major hemorrhage (5/15), and respiratory arrest (1/15). Mean anesthesia time was 23±6 minutes. The vasectomized males were habituated to 2 pigeon houses together with fertile females. Another pigeon house with fertile pairs acted as control. All eggs laid were candled weekly to assess fertility. In the 2 pigeon houses with vasectomized males, the mean fertilization rate was 0.9% (5/563), while in the control pigeon house, the rate was 100% (39/39). The results indicate that endoscopic vasectomy of male feral pigeons may be a promising tool for field control of feral pigeon populations, especially in combination with other methods such as pigeon houses.

  6. From low to high fertility in Sulawesi (Indonesia) during the colonial period: explaining the 'first fertility transition'.

    Science.gov (United States)

    Henley, David

    2006-11-01

    This paper examines the past transition from low to high fertility which, in Indonesia as elsewhere, preceded the return to lower birth rates. Data from two parts of the island of Sulawesi where fertility rose during the colonial period are used to explain both why it rose, and why it was originally low. Economic conditions, it is argued, were the most important factors, affecting fertility via the supply of income and the demand for labour. Two schematic models of the 'first fertility transition' are proposed. In areas with low population densities and area-extensive forms of agriculture responsive to commercial stimuli, birth rates rose as the growth of commerce raised levels of prosperity, facilitated marriage, and undermined institutions such as debt-slavery which had previously acted to restrict marital fertility. In densely populated areas with labour-intensive agriculture and heavy state taxation in labour, fertility rose in response to demands for women's (and possibly child) labour that did not necessarily lead to gains in income.

  7. Cancer treatment: fertility and sexual side effects in women

    Science.gov (United States)

    ... Alternative Names Radiotherapy - fertility; Radiation - fertility; Chemotherapy - fertility; Sexual dysfunction - cancer treatment References American Cancer Society. Fertility and women with cancer. Updated November 6, 2013. www.cancer. ...

  8. Fertility in myotonic dystrophy in Saguenay-Lac-St-Jean: a historical perspective.

    Science.gov (United States)

    Dao, T N; Mathieu, J; Bouchard, J P; De Braekeleer, M

    1992-11-01

    Myotonic dystrophy (MD) is an autosomal dominant disorder that has a high prevalence in Saguenay-Lac-St-Jean. A case-control study, based on a population register, of 373 MD patients who married in this region between 1855 and 1971 was conducted to determine whether their fertility was affected by the disorder. Six demographic parameters, that is the number of children, the age at marriage, the ages at the time of birth of the first and the last child, the interval between the marriage and the birth of the first child, and the interval between consecutive births, were analyzed. The mean number of children born to MD and control individuals was not different (P > 0.05). However, MD males had more children than MD females although they have started delaying their marriage since 1921. Fertility fell significantly in both the MD and control groups during the period of observation. This change reflects the decline in fertility of French Canadians in general during this period, but mainly after 1940.

  9. Low fertilization rates in a pelagic copepod caused by sexual selection?

    DEFF Research Database (Denmark)

    Ceballos, Sara; Sichlau, Mie Hylstofte; Heuschele, Jan;

    2014-01-01

    random mating. Such low fertilization rates are normally related to environmental factors such as poor food or low densities, which we could not confirm in our experiment. Male density was negatively related to fertilization rate, and a large fraction of males did not mate in laboratory incubations. We...... therefore suggest that sexual selection, through mate choice or male–male competition could account for low fertilization rates of females in populations of pelagic copepods during some periods of the year...

  10. Low forager fertility: demographic characteristic or methodological artifact?

    Science.gov (United States)

    Early, J D

    1985-09-01

    Anthropological literature has long held that traditional foraging populations have low fertility levels. This research examines the number of live births per woman for 9 non-western forager groups who have been investigated in the last 20 years. Data are derived from 1) birth registration systems, 2) surveys conducted during short stays with the group, and 3) surveys conducted as part of longer ethnographic studies. Fertility rates for the groups are 1) 3.5 for the Kiunga area of Papula, New Guinea, 2) 4.2 for Northern Territory Australian aborigines, 3) 5.0 for Cayapo groups in Brazil, 4) 5.3 for Hiowe people of New Guinea, 5) 5.7 for 3 Xavante groups in Brazil, 6) 6.0 for West Alaskan Eskimos, 7) 6.9 for Nunamiut Eskimos of Alaska, 8) 7.6 for the Bisman-Asmat group of Indonesian New Guinea, and 9) 8.4 for the Winikina Warao of Venezuela. Since fertility rates are highest when ethnographic studies, which allow for question clarification, memory recall, and cross-checking, are used, the author believes that high fertility rates most accurately represent forager societies. Research on the Dobe ]Kung (fertility rate - 4.7), may contradict these findings, but the author believes that the ]Kung fertility rates are higher than reported because of infanticide practices, sexual abstinence during lactation, and disease related fertility problems. In summary, the study finds high fertility (7-9 births) in traditional foraging societies. Although the study examines small populations, correlation strength and overall consistency help verify the results.

  11. Adverse childhood event experiences, fertility difficulties and menstrual cycle characteristics.

    Science.gov (United States)

    Jacobs, Marni B; Boynton-Jarrett, Renee D; Harville, Emily W

    2015-01-01

    Increased childhood adversity may be affect adult fertility, however, the mechanism through which this occurs is unclear. Menstrual cycle abnormalities are predictive of fertility difficulties, and stress influences menstrual cycle characteristics. Here, we assess whether adverse childhood experiences (ACEs) are associated with fertility difficulties and menstrual cycle dysregulation, offering a plausible mechanism for the link between lifetime stress and fertility. From April 2012 to February 2014, 742 pregnant and non-pregnant women aged 18-45 years residing in southeastern Louisiana provided information on childhood adversity and reproductive history. Associations between ACEs and fertility difficulties and menstrual cycle patterns were evaluated. As the number of ACEs increased, risk of fertility difficulties and amenorrhea increased (RR = 1.09, 95% CI 1.05-1.13 and RR = 1.07, 95% CI 1.04-1.10, respectively), while fecundability decreased [fecundability ratio (FR) = 0.97, 95% CI 0.95-1.00]. Compared to women with no adversity, women in the high adversity group were more likely to experience both infertility and amenorrhea (RR = 2.75, 95% CI 1.45-5.21 and RR = 2.54, 95% CI 1.52-4.25, respectively), and reduced fecundability (FR = 0.75, 95% CI 0.56-1.00). Although similar patterns were seen for menstrual cycle irregularity, associations were diminished. Associations did not materially change following adjustment for age, body mass index, race, education, smoking and income. Results are constrained by the self-report nature of the study and the limited generalizability of the study population. To our knowledge, this is the first study to present evidence of a link between childhood stressors, menstrual cycle disruption and fertility difficulties. The effect of childhood stress on fertility may be mediated through altered functioning of the HPA axis, acting to suppress fertility in response to less than optimal reproductive circumstances.

  12. Marital moratorium and fertility control in China.

    Science.gov (United States)

    Tien, H Y

    1970-11-01

    Abstract Since 1949, the issue of marital postponement has been extensively discussed in China. Unlike some other means of fertility control (e.g. abortion and oral contraception), marital postponement has been welcomed with the fewest misgivings. Lately, marital postponement has also been given renewed emphasis by those outside China who see a weak link between various current national family planning programmes based on improved technology and the goal of fertility reduction. One aim of this paper is to render a comprehensive account of the marital postponement programme in China in the course of the birth control campaign during the last two decades. The second objective is to discuss the lessons that may be learned from it, and its implications for the current fertility controversy in the United States. Four general conclusions emerge from a careful analysis of the available documents: (1) in China, proponents of delayed marriage were divided on the question of how to secure its general acceptance. One issue dividing them was whether or not China's Marriage Law of 1950 should be amended in order to achieve it. Those who favoured raising the minimum legal age disagreed on the details of the presumably needed change. There is enough evidence to suggest that medical personnel were the chief advocates of compulsory postponement of marriage. The government rejected this legalistic approach and, in so doing, agreed with Chen Ta (a noted demographer) and others who sought to achieve postponement of marriage through appropriate social and economic measures. (2) Decisions to delay matrimony in different socio-cultural settings are not necessarily identical sociological phenomena. In some societies, (e.g. the United States), they may amount to no more than a course of action that enables individuals involved to realize or develop alternate goals in life. In others (e.g. China), they are literally acts of rebellion. (3) The fertility policy dispute has been carried on in

  13. Self-incompatibility systems: barriers to self-fertilization in flowering plants.

    Science.gov (United States)

    Rea, Anne C; Nasrallah, June B

    2008-01-01

    Flowering plants (angiosperms) are the most prevalent and evolutionarily advanced group of plants. Success of these plants is owed to several unique evolutionary adaptations that aid in reproduction: the flower, the closed carpel, double fertilization, and the ultimate products of fertilization, seeds enclosed in the fruit. Angiosperms exhibit a vast array of reproductive strategies, including both asexual and sexual, the latter of which includes both self-fertilization and cross-fertilization. Asexual reproduction and self-fertilization are important reproductive strategies in a variety of situations, such as when mates are scarce or when the environment remains relatively stable. However, reproductive strategies promoting cross-fertilization are critical to angiosperm success, since they contribute to the creation of genetically diverse populations, which increase the probability that at least one individual in a population will survive given changing environmental conditions. The evolution of several physical and genetic barriers to self-fertilization or fertilization among closely related individuals is thus widespread in angiosperms. A major genetic barrier to self-fertilization is self-incompatibility (SI), which allows female reproductive cells to discriminate between "self" and "non-self" pollen, and specifically reject self pollen. Evidence for the importance of SI in angiosperm evolution lies in the highly diverse set of mechanisms used by various angiosperm families for recognition of self pollen tube development and preventing self-fertilization.

  14. Enteropathogenic bacterial contamination of a latosol following application of organic fertilizer

    Directory of Open Access Journals (Sweden)

    Pedro Alexandre Escosteguy

    2015-10-01

    Full Text Available Poultry manure is used as fertilizer in natura, but little is known about whether it contaminates the soil with pathogenic organisms. The aim of this study was to assess the effects of organic, organomineral and mineral fertilizers on soil contamination by enteric pathogens, using poultry manure as the organic fertilizer. Manure was applied in field experiments at rates of 7.0 ton. ha-1 (maize crop, 2008/2009, 8.0 ton. ha-1 (wheat crop, 2009 and 14 ton. ha-1 (maize crop, 2010/2011. Organomineral fertilizer was applied at the same rates but was comprised of 50% manure and 50% mineral fertilizer. At 30 and 70 days after fertilization, the organic fertilizer and the upper 0-5 cm layer of the soil were tested for the presence of helminth eggs and larvae and enteropathogenic bacteria. Fecal and non-fecal coliforms (Escherichia coli and Clostridium perfringes were found in the organic fertilizer, but neither Salmonella spp. nor enteroparasites were detected. The population of enteropathogenic bacteria in the soil was similar among the treatments for all crops at both evaluation times. The population of thermotolerant coliforms in the organic fertilizer was larger than the maximum level allowed in Brazil, but neither the organic or nor the organomineral fertilizer contaminated the soil.

  15. Menstrual cycle pattern and fertility

    DEFF Research Database (Denmark)

    Kolstad, Henrik A.; Bonde, Jens Peter; Hjøllund, Niels Henrik;

    1999-01-01

    To characterize how the menstrual cycle pattern relates to fertility regardless of potential biases caused by inappropriate coital timing during the menstrual cycle or early embryonal loss.......To characterize how the menstrual cycle pattern relates to fertility regardless of potential biases caused by inappropriate coital timing during the menstrual cycle or early embryonal loss....

  16. Family Systems and Fertility Intentions

    NARCIS (Netherlands)

    Mönkediek, Bastian; Bras, Hilde

    2017-01-01

    Family systems, as normative frameworks in which family processes unfold, are believed to exert a major influence on fertility. While a number of studies have addressed family system effects on family size and the timing of births, the question of how family systems influence fertility intentions

  17. ASSESSMENT OF PERCHLORATE IN FERTILIZERS

    Science.gov (United States)

    Perchlorate has been positively detected only in those materials known to be derived from Chilean caliche, which constitute less than 0.2% of U.S. fertilizer application. The data obtained in the preponderance of investigations suggest that fertilizers do not contribute to envir...

  18. Phosphate fertilizer influence on {sup 238} U content in vegetables

    Energy Technology Data Exchange (ETDEWEB)

    Lauria D, C.; Rodrigues S, J.I. [Instituto de Radioprotecao e Dosimetria (IRD/CNEN), Av. Salvador Allende s/n, Rio de Janeiro-RJ (Brazil); Ribeiro, F.C.A. [Centro Regional de Ciencias Nucleares (CRCN/CNEN) Av. Prof. Luiz Freire 200 Cidade Universitaria Recife-PE (Brazil)]. e-mail: dejanira@ird.gov.br

    2006-07-01

    Uranium is a naturally radioactive element, which is usually found in soils, superficial and ground water, vegetables and animals. After ingestion by human beings, most is excreted in few days by feces and urine, without reaching the bloodstream. However, a small part circulates through the body, being accumulated in the soft tissues, as kidneys. A minor fraction can remain in bones per some years, being able through the radioactive decay to irradiate adjacent tissues. Phosphate fertilizers used in conventional crop management can present variable amounts of uranium. In accordance with origin and use, the fertilizer can raise the content of this element in vegetables, and consequently to increase the human exposure for radiation due the consumption of vegetables. It is estimated that the use of phosphate fertilizer has at least doubled the prolonged exposure of humans from ingestion of food. This work aims to evaluate the contribution of organic and chemical fertilizer on the concentration of {sup 238} U in vegetable samples. An experiment with black beans (a very important vegetable for Brazilian people) was conducted in a field which soil has never been fertilized with any sort of fertilizer, located near to the Rio de Janeiro city. On the organic management, bovine manure was used, while on conventional management urea, potassium chloride and superphosphate were used. Simultaneously, black bean samples from not fertilized management were collected. In addition, lettuce and carrot samples from organic and conventional managements were collected in Nova Friburgo farms (the most important vegetable supplier of Rio de Janeiro city market). The analyses of {sup 238} U have been carried out by conventional fluorimetric method. The geometric mean of {sup 238} U concentrations in the carrot and lettuce samples from conventional management were similar with those from organic management, while for beans the conventional samples had higher values than those ones found in

  19. Greenhouse Gas Emissions from Solid and Liquid Organic Fertilizers Applied to Lettuce.

    Science.gov (United States)

    Toonsiri, Phasita; Del Grosso, Stephen J; Sukor, Arina; Davis, Jessica G

    2016-11-01

    Improper application of nitrogen (N) fertilizer and environmental factors can cause the loss of nitrous oxide (NO) to the environment. Different types of fertilizers with different C/N ratios may have different effects on the environment. The focus of this study was to evaluate the effects of environmental factors and four organic fertilizers (feather meal, blood meal, fish emulsion, and cyano-fertilizer) applied at different rates (0, 28, 56, and 112 kg N ha) on NO emissions and to track CO emissions from a lettuce field ( L.). The study was conducted in 2013 and 2014 and compared preplant-applied solid fertilizers (feather meal and blood meal) and multiple applications of liquid fertilizers (fish emulsion and cyano-fertilizer). Three days a week, NO and CO emissions were measured twice per day in 2013 and once per day in 2014 using a closed-static chamber, and gas samples were analyzed by gas chromatography. Preplant-applied solid fertilizers significantly increased cumulative NO emissions as compared with control, but multiple applications of liquid fertilizers did not. Emission factors for NO ranged from 0 to 0.1% for multiple applications of liquid fertilizers and 0.6 to 11% for preplant-applied solid fertilizers, which could be overestimated due to chamber placement over fertilizer bands. In 2014, solid fertilizers with higher C/N ratios (3.3-3.5) resulted in higher CO emissions than liquid fertilizers (C/N ratio, 0.9-1.5). Therefore, organic farmers should consider the use of multiple applications of liquid fertilizers as a means to reduce soil greenhouse gas emissions while maintaining high yields.

  20. Children Procedures and Treatment (Fertility Issues)

    Medline Plus

    Full Text Available ... approach the subject of fertility preservation with their cancer-stricken child? How is the Oncofertility Consortium addressing the fertility preservation needs of children? How do cancer and cancer treatment affect a child's fertility? Why ...

  1. Children Procedures and Treatment (Fertility Issues)

    Medline Plus

    Full Text Available ... approach the subject of fertility preservation with their cancer-stricken child? How is the Oncofertility Consortium addressing the fertility preservation needs of children? How do cancer and cancer treatment affect a child's fertility? Why ...

  2. Internal fertilization in an oviparous frog.

    Science.gov (United States)

    Townsend, D S; Stewart, M M; Pough, F H; Brussard, P F

    1981-04-24

    Eleutherodactylus coqui, an oviparous frog, undergoes internal fertilization. If this mode of fertilization occurs in other species of anurans, interpretations of anuran reproductive strategies based on the assumption of external fertilization must be reviewed.

  3. [Thyroid gland and fertility].

    Science.gov (United States)

    Andreeva, P

    2014-01-01

    It is well-known that the thyroid hormones are associated with a number of aspects of the human reproduction. Both states, hyperthyroidism and hypothyroidism, have significant effect on the estrogen and androgen metabolism, the menstrual function and on fertility. The role of thyroid hormones (TH) during infertility has been little exploited. Interesting facts are that TH deficiency is more common in women with polycystic ovary syndrome (PCOS) and in certain cases with unexplained infertility. There are very few studies on the effect and paracrine regulation of TH and its receptors in the female reproductive tract. This report provides an overview of the most common thyroid disorders and their impact on ovarian function and reproductive performance in women as well as in cases with infertility and the implementation of assisted reproductive technologies (ART).

  4. Double fertilization in Helianthus

    Directory of Open Access Journals (Sweden)

    J. Telżyńska

    2015-01-01

    Full Text Available After controlled pollination of Helianthus annuus L. florets, the whole course of fertilization is described and documented on 24 microphotos. The timing of events is evaluated. The average cell cycle in the proembryo is 2 hours and the nuclear cycle in endosperm - 60 minutes.Plasmoptysis is suggested as the mechanism of pollen tube opening in the synergid. The structure of the thread-like sperm nucleus is interpreted as an end to end union of chromosomes, and the morphological changes of the sperm nuclei are explained as folding and coiling, based on a spiralization mechanism of chromosomes. Cytochemical observations indicating ribosome formation in the course of the nuclear cycles in the endosperm are described. The mechanisms accelerating nuclear cycles in the endosperm are discussed.

  5. [Child survival, fertility, and family planning in Africa. Uncertain prospects].

    Science.gov (United States)

    Mbacke, C

    1987-10-01

    externally-imposed improvements. Availability of family planning services becomes an important factor in the extent and speed of fertility decline once the desired number of surviving children becomes smaller than that implied in a natural fertility regime. The author found that sustained fertility declines were usually preceded by mortality declines, but improved health conditions did not automatically lead to fertility declines. The pronatalist attitudes of individual households, rational though they might be, are becoming a problem for African governments burdened by the need to provide services for ever growing populations. Lloyd and Ivanov believe that infant mortality is still too high in most of Africa to encourage family planning; they recommend that sterilization be stressed for families that have achieved their desired size. This work argues however that a future fertility decline is not assured and that reversible contraceptives should be available for the population sectors desiring them.

  6. Effect of Nitrogen Fertilizer on Herbivores and Its Stimulation to Major Insect Pests in Rice

    Directory of Open Access Journals (Sweden)

    Zhong-xian LU

    2007-03-01

    Full Text Available Nitrogen is one of the most important factors in development of herbivore populations. The application of nitrogen fertilizer in plants can normally increase herbivore feeding preference, food consumption, survival, growth, reproduction, and population density, except few examples that nitrogen fertilizer reduces the herbivore performances. In most of the rice growing areas in Asia, the great increases in populations of major insect pests of rice, including planthoppers (Nilaparvata lugens and Sogatella furcifera, leaffolder (Cnaphalocrocis medinalis, and stem borers (Scirpophaga incertulas, Chilo suppressalis, S. innotata, C. polychrysus and Sesamia inferens were closely related to the long-term excessive application of nitrogen fertilizers. The optimal regime of nitrogen fertilizer in irrigated paddy fields is proposed to improve the fertilizer-nitrogen use efficiency and reduce the environmental pollution.

  7. Effect of Nitrogen Fertilizer on Herbivores and Its Stimulation to Major Insect Pests in Rice

    Institute of Scientific and Technical Information of China (English)

    LU Zhong-xian; YU Xiao-ping; Kong-luen HEONG; HU Cui

    2007-01-01

    Nitrogen is one of the most important factors in development of herbivore populations. The application of nitrogen fertilizer in plants can normally increase herbivore feeding preference, food consumption, survival, growth, reproduction, and population density, except few examples that nitrogen fertilizer reduces the herbivore performances. In most of the rice growing areas in Asia, the great increases in populations of major insect pests of rice, including planthoppers (Nilaparvata lugens and Sogatella furcifera), leaffolder (Cnaphalocrocis medinalis), and stem borers (Scirpophaga incertulas, Chilo suppressalis, S. innotata, C. polychrysus and Sesamia inferens) were closely related to the long-term excessive application of nitrogen fertilizers. The optimal regime of nitrogen fertilizer in irrigated paddy fields is proposed to improve the fertilizer-nitrogen use efficiency and reduce the environmental pollution.

  8. Acceptors of Population Programme in Pakistan

    OpenAIRE

    SABIHA HASAN SyED

    1981-01-01

    Data from Pakistan's population planning programme, the Nationa11mpact Survey (1968) and the Pakistan Fertility Survey (1975) are ana1ysed to estimate the number of 'births averted' in Pakistan by various contraceptives. Limitations of the population planning programme statistics for determining the impact of the programme on fertility rates are pointed out.

  9. High fertility Gambians in low fertility Spain: The dynamics of child accumulation across transnational space

    Directory of Open Access Journals (Sweden)

    Papa Sow

    2007-05-01

    Full Text Available Based on an analysis of the Spanish census and the January 1, 2005 municipal register and on exploratory fieldwork in Catalonia, this paper combines ethnography and demography, in conjunction with current Spanish reunification law, to examine the dynamics of what appears to be high fertility among Gambian immigrants living in Spain. We suggest that this high fertility rate reflects several things. One is the high costs of living in Spain for an unskilled, often-undocumented, but also relatively-longstanding SubSaharan group from a homeland with high rates of fertility: a homeland with which close ties remain vital for migrants in highly marginal conditions. Another is the replacement, in some cases, of older wives by younger ones from Africa, resulting in high rates of reproduction for short slices of time by a circulating pool of young women. We focus, however, on the role of Spanish and European policies themselves in shaping these numbers, particularly those policies that place restrictions on the free movement of people. We conclude that the most interesting demographic facet of this population may not be high fertility but rather the paradoxical dynamics of child accumulation in particular geographic regions as an artifact of Spanish law itself.

  10. Long-term effect of mineral fertilizers and amendments on microbial dynamics in an alfisol of Western Himalayas.

    Science.gov (United States)

    Mahajan, S; Kanwar, S S; Sharma, S P

    2007-03-01

    The microbial dynamics expressed in terms of culturable microbial populations i.e. bacteria, fungi, actinomycetes and Azotobacter were measured after 33 years of continuous application of mineral fertilizers and amendments to an acid alfisol. The bacterial, fungal and Azotobacter populations were maximum in plots treated with mineral fertilizers and FYM (100%NPK+FYM) while actinomycetes population was maximum in mineral fertilizes and lime treated plots (100%NPK+Lime). The bacterial population decreased and fungal population increased with increasing levels of NPK i.e. from 50% to 150%NPK. Bacillus species of bacteria and Gliocladium, Aspergillus and Rhizopus species of fungi were the main dominating culturable microorganisms in all the treatments. The FYM and lime amended plots sustained crop productivity and microbial populations at higher levels than rest of the mineral fertilizer treatments. The nitrogenous fertilizers alone had the most deleterious effect on crop productivity and the biological soil environment.

  11. Short-term fertilizer application alters phenotypic traits of symbiotic nitrogen fixing bacteria

    Directory of Open Access Journals (Sweden)

    Anna K. Simonsen

    2015-10-01

    Full Text Available Fertilizer application is a common anthropogenic alteration to terrestrial systems. Increased nutrient input can impact soil microbial diversity or function directly through altered soil environments, or indirectly through plant-microbe feedbacks, with potentially important effects on ecologically-important plant-associated mutualists. We investigated the impacts of plant fertilizer, containing all common macro and micronutrients on symbiotic nitrogen-fixing bacteria (rhizobia, a group of bacteria that are important for plant productivity and ecosystem function. We collected rhizobia nodule isolates from natural field soil that was treated with slow-release plant fertilizer over a single growing season and compared phenotypic traits related to free-living growth and host partner quality in these isolates to those of rhizobia from unfertilized soils. Through a series of single inoculation assays in controlled glasshouse conditions, we found that isolates from fertilized field soil provided legume hosts with higher mutualistic benefits. Through growth assays on media containing variable plant fertilizer concentrations, we found that plant fertilizer was generally beneficial for rhizobia growth. Rhizobia isolated from fertilized field soil had higher growth rates in the presence of plant fertilizer compared to isolates from unfertilized field soil, indicating that plant fertilizer application favoured rhizobia isolates with higher abilities to utilize fertilizer for free-living growth. We found a positive correlation between growth responses to fertilizer and mutualism benefits among isolates from fertilized field soil, demonstrating that variable plant fertilizer induces context-dependent genetic correlations, potentially changing the evolutionary trajectory of either trait through increased trait dependencies. Our study shows that short-term application is sufficient to alter the composition of rhizobia isolates in the population or community

  12. Short-term fertilizer application alters phenotypic traits of symbiotic nitrogen fixing bacteria.

    Science.gov (United States)

    Simonsen, Anna K; Han, Shery; Rekret, Phil; Rentschler, Christine S; Heath, Katy D; Stinchcombe, John R

    2015-01-01

    Fertilizer application is a common anthropogenic alteration to terrestrial systems. Increased nutrient input can impact soil microbial diversity or function directly through altered soil environments, or indirectly through plant-microbe feedbacks, with potentially important effects on ecologically-important plant-associated mutualists. We investigated the impacts of plant fertilizer, containing all common macro and micronutrients on symbiotic nitrogen-fixing bacteria (rhizobia), a group of bacteria that are important for plant productivity and ecosystem function. We collected rhizobia nodule isolates from natural field soil that was treated with slow-release plant fertilizer over a single growing season and compared phenotypic traits related to free-living growth and host partner quality in these isolates to those of rhizobia from unfertilized soils. Through a series of single inoculation assays in controlled glasshouse conditions, we found that isolates from fertilized field soil provided legume hosts with higher mutualistic benefits. Through growth assays on media containing variable plant fertilizer concentrations, we found that plant fertilizer was generally beneficial for rhizobia growth. Rhizobia isolated from fertilized field soil had higher growth rates in the presence of plant fertilizer compared to isolates from unfertilized field soil, indicating that plant fertilizer application favoured rhizobia isolates with higher abilities to utilize fertilizer for free-living growth. We found a positive correlation between growth responses to fertilizer and mutualism benefits among isolates from fertilized field soil, demonstrating that variable plant fertilizer induces context-dependent genetic correlations, potentially changing the evolutionary trajectory of either trait through increased trait dependencies. Our study shows that short-term application is sufficient to alter the composition of rhizobia isolates in the population or community, either directly

  13. Effects of the fertility transition on birth seasonality in the Netherlands

    NARCIS (Netherlands)

    Haandrikman, K.; van Wissen, L.J.G.

    2008-01-01

    Synchronous with the decline in fertility that took place in the post-war period in the Netherlands, patterns of birth seasonality changed as well. In this paper seasonal fluctuations in fertility in the Netherlands are examined using population register data for the period 1952 to 2005. The peak in

  14. Effects of the fertility transition on birth seasonality in the Netherlands

    NARCIS (Netherlands)

    Haandrikman, K.; van Wissen, L.J.G.

    2008-01-01

    Synchronous with the decline in fertility that took place in the post-war period in the Netherlands, patterns of birth seasonality changed as well. In this paper seasonal fluctuations in fertility in the Netherlands are examined using population register data for the period 1952 to 2005. The peak in

  15. Fertility of Technosols constructed with urban wastes

    Science.gov (United States)

    Rokia, Sarah; Sere, Geoffroy; Deeb, Maha; Fournier, Frantz; Nehls, Thomas; Damas, Olivier; Vidal-Beaudet, Laure; Schwartz, Christophe

    2014-05-01

    Growing plants in urban areas requires large amounts of arable earth that is a non-renewable resource. Increase of urban population leads to the production of large qunatities of wastes and by-products that are only partly recycled as a resource and quite systematically exported out of urban areas. To preserve more natural soil resources (forest and agricultural soils), a strategy of waste recycling as fertile substrates is proposed. Eleven wastes are selected for their environmental harmlessness and their contrasted physico-chemical properties for their potential use in pedological engineering. The aim is (i) to demonstrate the feasibility of the construction of fertile substrates exclusively with wastes and by-products and (ii) to model their physico-chemical properties following various types, number and proportions of constitutive wastes. Twenty-five binary and ternary combinations are tested at different ratios for total carbon, Olsen available phosphorus, cation exchange capacity, water pH, water retention capacity and bulk density. Dose-response curves describe the variation of physico-chemical properties of mixtures depending on the type and ratio of selected wastes. Quite all of the mixtures have properties very near to those of natural soils. Some of them present more extreme urban soil features, especially for pH and POlsen. The fertility of the new substrates is modelled by multilinear regressions for the main soil properties. This allows to predict the fertility of constructed Technosols and participates to the development of soil eco-conception in urban and industrial areas (Rokia et al., Modelling agronomic properties of Technosols constructed with urban wastes, Waste Management (2013), 10.1016/j.wasman.2013.12.016). Keywords: constructed Technosol, pedological engineering, agronomic properties

  16. Population policy summaries of countries of the ESCAP region.

    Science.gov (United States)

    1987-12-01

    Pakistan's 1985-88 Sixth Five-Year Plan. Policy in the Philippines aims to reduce the rate of population growth to that which is in keeping with national resources and employment opportunities. Likewise, the government of Thailand recognizes that it's rapid growth in population is beyond the means of available domestic resources and employment opportunities, but deems its rate of population growth, characterized by declining fertility, to be satisfactory.

  17. The impact of freedom on fertility decline.

    Science.gov (United States)

    Campbell, Martha M; Prata, Ndola; Potts, Malcolm

    2013-01-01

    Although fertility decline often correlates with improvements in socioeconomic conditions, many demographers have found flaws in demographic transition theories that depend on changes in distal factors such as increased wealth or education. Human beings worldwide engage in sexual intercourse much more frequently than is needed to conceive the number of children they want, and for women who do not have access to the information and means they need to separate sex from childbearing, the default position is a large family. In many societies, male patriarchal drives to control female reproduction give rise to unnecessary medical rules constraining family planning (including safe abortion) or justifying child marriage. Widespread misinformation about contraception makes women afraid to adopt modern family planning. The barriers to family planning can be so deeply infused that for many women the idea of managing their fertility is not considered an option. Conversely, there is evidence that once family planning is introduced into a society, then it is normal consumer behaviour for individuals to welcome a new technology they had not wanted until it became realistically available. We contend that in societies free from child marriage, wherever women have access to a range of contraceptive methods, along with correct information and backed up by safe abortion, family size will always fall. Education and wealth can make the adoption of family planning easier, but they are not prerequisites for fertility decline. By contrast, access to family planning itself can accelerate economic development and the spread of education.

  18. Effects of pyridoxine on male fertility.

    Science.gov (United States)

    Tsutsumi, S; Tanaka, T; Gotoh, K; Akaike, M

    1995-08-01

    Pyridoxine (PN) was intraperitoneally given at 250 and 500 mg/kg to male rats for 2, 4, or 6 weeks, and its effects on male fertility evaluated in terms of the optimal treatment period and detection parameters. Animals of all PN groups showed depression of body weight gains from week I of treatment onwards, significant at all but the 250 mg/kg 2 week administration I week time point. After 2 weeks treatment, the testes demonstrated only very slight histopathological changes. The 4- and 6-week treatments caused decreased spermatozoal motility and some histopathological changes in the testes including degeneration of germinal epithelial cells with both doses and also decreases in the fertility index and mean velocity of sperm, reduction in the testes and epididymides weights, and changes in testicular proteins. In the animals undergoing a 4-week recovery period following 4 or 6 weeks exposure, changes disappeared with the 250 mg/kg dose, but still remained with 500 mg/kg. From these findings, it is concluded that a treatment period of 4 weeks is sufficient for evaluation of drug effects on male fertility and that histopathology can detect the slightest toxic effects on the testis.

  19. Satisfaction with life as an antecedent of fertility: Partner + Happiness = Children?

    Directory of Open Access Journals (Sweden)

    Nick Parr

    2010-04-01

    Full Text Available This paper examines the relationships between satisfaction with life in general, particular domains of life, the partner, and parental relationships with existing children, and subsequent fertility. The data are from 2,948 women and 2,622 men aged 15 to 44 years from a longitudinal survey of the household population in Australia. For both sexes a strong positive relationship between prior satisfaction with life and fertility two years later is found. Men's satisfaction with their partner and with their partner's relationship with existing children are positively related to fertility. Fertility is also related to age, parity, marital status, education, employment and birthplace.

  20. Agronomic performance of male-sterile and fertile maize genotypes at two plant populations Performace agronômica de genótipos macho-estéreis e férteis de milho em duas densidades de semeadura

    Directory of Open Access Journals (Sweden)

    Luís Sangoi

    1996-12-01

    Full Text Available This experiment was conducted in 1994 at Ames, Iowa, US to test whether cytoplasmic male-sterility can be used to decrease barrenness and to increase grain yield of maize at two plant populations. Four genotypes were tested: a hybrid (NK 6330 and an inbred, wifh sterile and fertile counterparts. Each genotype owas evaluated at plant populations equivalent to 25,000 and 75,000 pl. ha-1. Hybrids produced higher grain yield than inbreds at both plant populations. Gram yield was higher at 75,000 than at 25,000 pl. ha-1. No difference in gram yield, number of ears per plant, number of grains per ear, tassel length, and tassel number of branches was found between sterile and fertile counterparts of the inbred and hybrid, regardiess of plant population. Fertile genotypes bore heavier tassels at anthesis than their sterile counterparts. Adequate precipitation distribution and high fertility level in the soil probably decreased competition between tassel and ears, mitigating potential yield benefits of suppressing genetically pollen production.Este experimento foi conduzido em Ames, Iowa, US durante o ano agrícola de 1994, tendo como objetivo avaliar se a macho-esterelidade genético-citoplasmática pode ser utilizada para aumentar o rendimento de grãos de milho em diferentes populações de planta. Quatro genótipos foram utilizados: um híbrido (NK 6330 e uma linhagem, ambos em suas versões fértil e macho-estéril. Cada genótipo foi avaliado em duas densidades de semeadura, equivalentes a 25.000 e 75.000 pl.ha-1. Os híbridos produziram maiores rendimentos de grão do que as linhagens nas duas populações utilizadas. O rendimento de grãos por área foi maior em 75.000 do que em 25.000 pl.ha-1. Nenhuma diferença significativa em termos de rendimento de grãos, número de espigas por planta, número de grãos por espiga, comprimento e número de ramos do pendão, foi observada entre genótipos férteis e macho-estéreis, independentemente da

  1. Research Progress in the Effect and Mechanism of Fertilization Measures on Soil Fertility

    Institute of Scientific and Technical Information of China (English)

    Dongfeng; HUANG; Limin; WANG; Weihua; LI; Xiaoxuan; QIU

    2015-01-01

    This paper firstly summarized the domestic and foreign research progress in the relationship between fertilization measures and soil fertility. It elaborated the relationship between fertilization measures and basic physical and chemical properties,soil enzyme activity,soil microorganism fertility index,and soil animal fertility index. It pointed out future researches about the relationship between fertilization measures and soil fertility include:( i) the relationship between fine and high efficient input of organic fertilizer and soil fertility,( ii) in-depth research of soil zoology fertility index,( iii) soil biology about long-term fertilization,and( iv) soil fertilization and agricultural diffused pollution. It is intended to provide scientific reference for improving farmland soil fertility and maintaining excellent ecological environment of farmland through proper fertilization measures.

  2. Effect of pig dung fertilizer on zooplankton production

    African Journals Online (AJOL)

    SARAH

    2014-12-29

    Dec 29, 2014 ... zooplankton population, points out copepods dominance which are rotifers and cladocerans predators. Key-words: pig ... Aquaculture development, especially fish culture, is currently an ... zooplanktons were concentrated in a pond using a plankton net of .... dissolved oxygen between the fertilized and the.

  3. Caste, socio-economic status and fertility -- a study of proximate determinants of fertility in village Riwasa.

    Science.gov (United States)

    Arora, G

    1985-10-01

    The intermediary variables of ritual stratification, i.e., caste, and secular stratification, i.e., socioeconomic status, were examined to explain fertility in a survey of 140 fertile women in Riwasa village, Bhiwani District, Haryana state, India, in 1981. The subjects interviewed were equally divided among 17 castes on the basis of untouchability. The intermediary variables evaluated were caste-consciousness, modernization, conformity to family ethical codes and husband-wife communication. The fertility indices were live births, living children, expected additional births and ideal family size. Results were expressed in percentages. Results of the survey confirmed previous findings that fertility was inversely related to caste and socioeconomic status. These associations were explained here, however, by the behavior of the intermediary variables. Fertility was inversely related to level of modernization and to husband-wife communication. Although caste-consciousness and conformity to family ethical codes were directly related to fertility, even among the higher castes. There were no differences in this study population between high and middle socioeconomic class, probably because the high socioeconomic group in this village resembled middle class in typical urban settings.

  4. The Relationship of Socio-Demographic Factors, Fertility Behavior and Child’s Perceived Value with Fertility

    Science.gov (United States)

    Azmoude, Elham; Behnam, Haniye; Barati-Far, Saeede; Kabirian, Maryam

    2017-01-01

    ABSTRACT Background: Fertility intention is one of the strongest predictors of couple’s fertility behavior that is affected by many variables. This study aimed to identify the relationship of socio-demographic factors, fertility behavior, and child’s perceived value with fertility intention of women in a region in the east Iran Methods: In this descriptive cross-sectional study, 241 married women aged between 15 and 49 years of Torbat Heydariyeh City in 2015, were studied. The data collection scales included a demographic information form, fertility information questionnaire and Trommsdorff’s child value questionnaire. Data were analyzed using SPSS 16 by Chi-square, Kruskal-Wallis, t-independent test and logistic regression. The significance level of Pcosts of children (P=0.001). In addition, in subjects with children of both sexes, intention for childbearing was significantly lower when compared to subjects with only one sex in children (P=0.001). However, when the logistic regression test was performed, being housewife, number of children, having children of both sexes, benefit and costs of children showed statistical significance (Pcurrent children, having children of both sexes, and perceived childbearing costs are important in determining the odds that a woman will intend to have a child. These findings can contribute to the realization of new population programs towards higher fertility rate in the country. PMID:28409166

  5. Impact of air pollution on fertility: a systematic review.

    Science.gov (United States)

    Frutos, Víctor; González-Comadrán, Mireia; Solà, Ivan; Jacquemin, Benedicte; Carreras, Ramón; Checa Vizcaíno, Miguel A

    2015-01-01

    Air pollution has gained considerable interest because of the multiple adverse effects reported on human health, although its impact on fertility remains unclear. A systematic search was performed to evaluate the impact of air pollutants on fertility. Controlled trials and observational studies assessing animal model and epidemiological model were included. Occupational exposure and semen quality studies were not considered. Outcomes of interest included live birth, miscarriage, clinical pregnancy, implantation, and embryo quality. Ten studies were included and divided into two groups: animal studies and human epidemiological studies including the general population as well as women undergoing in vitro fertilization and embryo transfer (IVF/ET). Results from this systematic review suggest a significant impact of air pollution on miscarriage and clinical pregnancy rates in the general population, whereas among subfertile patients certain air pollutants seem to exert a greater impact on fertility outcomes, including miscarriage and live birth rates. Besides, studies in mammals observed a clear detrimental effect on fertility outcomes associated to air pollutants at high concentration. The lack of prospective studies evaluating the effect of air pollution exposure in terms of live birth constitutes an important limitation in this review. Thus, further studies are needed to confirm these findings.

  6. Fertility in Islamic Republic of Iran: Levels, Trends and Differentials during Three Decades (1967-1996

    Directory of Open Access Journals (Sweden)

    Kazem Mohammad

    2002-12-01

    The detailed nature of these data collected for each birth enabled fertility rates to be calculated for exact periods before the survey, for exact calendar years. Higher fertility rates were found for the period 10-15 and 15-20 years preceding the survey. These high fertility levels are probably due to some socio-economic changes in favor of higher level of fertility immediately after the 1979 revolution. However the results of the present survey show during 1967-1996, the TFR1 had dropped from 6.38 to 2.88 (an expected TFR based on fertility behavior during 1992-96. This decline was probably due to delay in marriage and policy changes in favor of population control particularly since 1987. Despite this potential fertility decline in recent years, Iran is expected to face a baby boom as the offspring who were born during the 1976-86 reach to the reproductive age in the coming decades.

  7. Effect of Fertilization on the Morphological Development of European Hophormbeam (Ostrya carpinifolia Scop. Seedlings

    Directory of Open Access Journals (Sweden)

    Şemsettin Kulaç

    2016-10-01

    Full Text Available In this study, in order to help the mass production of seedlings, the effect of fertilization on the morphological development of hornbeam leafy European hophornbeam (Ostry carpinifolia Scop seedlings were investigated. For this, seedlings, which were obtained from the seeds coming from different European hophornbeam populations (Düzce-Yığılca, Antalya-Finike, Antalya-Akseki, Kastamonu-Şehdağ ve Adana-Saimbeyli from various parts of Turkey, were used. European hophornbeam seedlings were treated with different fertilizers, including urea, ammonium sulphate, compound fertilizer 15-15-15 and 20-20-0, and 6-9 months Osmocote release fertilizer, and effects of these fertilizers on the morphological characters were investigated. Fertilization contained the same amount of nitrogen, and was made in three different ways; (1 mixing with habitat, (2 topical application and (3 liquid application. The development of germinated European hophornbeam seeds, which were spring-sowed in the same medium were monitored during the vegetation period. At the end of vegetation period, seedlings were removed from the soil and morphological characteristics of root (seedling length, root collar diameter, root length, fresh root and stem weight of the seedlings, dried root and stem weight of the seedlings and bud number were measured. As a result, it was observed that fertilization positively affects the development of seedlings and depending on the fertilization type the seedlings of European hophornbeam populations were found to exhibit different improvements/growing. In addition, 6-9 months Osmocote release fertilizers were determined to be the best fertilizers affecting the morphological (diameter and height development of European hophornbeam populations effectively, and among the populations, Düzce and Kastamonu populations showed the best improvement/growing.

  8. Educational and social class assortative mating in fertile British couples.

    Science.gov (United States)

    Krzyżanowska, Monika; Mascie-Taylor, C G Nicholas

    2014-01-01

    Positive assortative mating for education and social position has been widely reported in a number of countries, but very few studies have tested whether or not educational or social class homogamy is related to differential fertility. This study examined the relationship between educational and social class assortative mating and fertility in a British national cohort. The analyses were based on 7452 husband-wife pairs from the British National Child Development Study (NCDS). The mean fertility was 3.22 children per couple; the number of children significantly increased from higher to lower social classes and from the more educated to the less educated. The extent of assortative mating for social class and educational level was related to fertility; as educational assortative mating decreased so did the average number of children, whereas the opposite trend was observed for social class. When assortative mating for education and social class were considered together, educational assortative mating was the more significant predictor of the number of children and educationally homogamous couples had higher fertility independent of their social class assortative mating. The relationship between assortative mating and fertility for education and social class appeared to be acting in the opposite direction.

  9. Fertilizer Management for Passion Fruit (Passifloraedulison Alaminos Clay Soil

    Directory of Open Access Journals (Sweden)

    Naominida C.Olermo

    2017-05-01

    Full Text Available Soils in rolling to hilly are strongly acidic and deficient in N, P and K – characteristics that are major constraints to high fruit yield like passion fruit. The importance of the macronutrient to passion fruit production showed that best yield was obtained with fertilization of 250-50-80 kg N-P2O5- K2Oha-1 . The degree of importance of N, P and K followed the order N > P > K. Yield reductions due to the absence of these nutrients from the complete treatment were 60%, 39% and 7%, respectively. Furthermore, best value per fruit was observed with fertilization 250-50-80 kg N-P2O5-K2O ha-1 .Mean value per fruit reductions due to non-application of N or P or K from the complete treatment were 29.74%, 17.75% and 11.19%, respectively. Higher juice characteristic (pH was observed from treatments with K compared from treatments without K. Performance of passion fruit from combined inorganic and organic fertilizers showed that highest yield and average value per fruit were produced by fertilization with 75% IF + 25% OF. Yield per hectare and average value per fruit reductions due to decreasing of percentage inorganic fertilizer (IF but increasing of percentage organic fertilizer (OF like 50% IF + 50% OF, 25% IF + 75% OF, and 100% OF were 26%, 37%, and 56% the former and 6%, 13%, and 41% the later, respectively

  10. Socioeconomic status and fertility before, during, and after the demographic transition: An introduction

    Directory of Open Access Journals (Sweden)

    Martin Dribe

    2014-07-01

    Full Text Available Background: Despite a long interest in the historical fertility transition, there is still a lack of knowledge about disaggregated patterns that could help us understand the mechanisms behind the transition. In previous research the widely held view is that there was a change in the association between social status and fertility in conjunction with the fertility transition, implying that fertility went from being positively connected to social status (higher status was connected with higher fertility to being negatively associated with fertility. Objective: The aim of this collection is to study socioeconomic patterns in the fertility transition in a variety of contexts using similar approaches and measures of socioeconomic status. Methods: All contributions use different kinds of micro-level socioeconomic and demographic data and statistical models in the analysis. Data either come from census-like records or population registers. Conclusions: There is no consistent evidence for the hypothesis that socioeconomic status was positively related to fertility before the demographic transition. While such a correlation was clearly present in some contexts it was clearly not in other contexts. There is more unanimous support for the idea that the upper-and middle classes acted as forerunners in the transition, while especially farmers were late to change their fertility behavior. It is also evident that both parity-specific stopping and prolonged birth intervals (spacing were important in the fertility transition.

  11. Effects of selected fertilizers on the life history of Bemisia tabaci (Hemiptera: Aleyrodidae) biotype B.

    Science.gov (United States)

    England, K M; Sadof, C S; Cañnas, L A; Kuniyoshi, C H; Lopez, R G

    2011-04-01

    We tested the effects among a purportedly sustainable water-soluble fertilizer, a conventional water-soluble fertilizer, an alternation of these, a controlled-release fertilizer, and a clear water control on the life-history traits of sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae; =Bemisia argentifolii Bellows & Perring) biotype B reared on poinsettia (Euphorbia pulcherrima Willdenow ex Klotzch). Free amino acids in petioles were measured to estimate plant nutrient assimilation and phloem nutritional quality for B. tabaci biotype B. The sustainable fertilizer produced plants with the highest concentration of amino acids. In contrast, fecundity of whiteflies was lowest in plants treated with the sustainable fertilizer and the water control. The relationship between total amino acids in phloem and survival was significantly quadratic, with the highest survival at intermediate levels. Fecundity, however, was negatively correlated with total amino acid content of the maternal host plant. Variation in total amino acid concentration in petioles of plants treated within fertilizer treatments makes it difficult to predict whether a particular fertilizer will produce plants with enough amino acids to deleteriously affect both survivorship and fecundity and yet yield a plant of good quality. Despite this limitation, we can conclude that the use of this sustainable fertilizer will not cause increases in whitefly populations relative to plants fertilized with water-soluble and slow-release fertilizers that deliver the same level of nitrogen to the plant.

  12. Regime shift in fertilizer commodities indicates more turbulence ahead for food security.

    Science.gov (United States)

    Elser, James J; Elser, Timothy J; Carpenter, Stephen R; Brock, William A

    2014-01-01

    Recent human population increase has been enabled by a massive expansion of global agricultural production. A key component of this "Green Revolution" has been application of inorganic fertilizers to produce and maintain high crop yields. However, the long-term sustainability of these practices is unclear given the eutrophying effects of fertilizer runoff as well as the reliance of fertilizer production on finite non-renewable resources such as mined phosphate- and potassium-bearing rocks. Indeed, recent volatility in food and agricultural commodity prices, especially phosphate fertilizer, has raised concerns about emerging constraints on fertilizer production with consequences for its affordability in the developing world. We examined 30 years of monthly prices of fertilizer commodities (phosphate rock, urea, and potassium) for comparison with three food commodities (maize, wheat, and rice) and three non-agricultural commodities (gold, nickel, and petroleum). Here we show that all commodity prices, except gold, had significant change points between 2007-2009, but the fertilizer commodities, and especially phosphate rock, showed multiple symptoms of nonlinear critical transitions. In contrast to fertilizers and to rice, maize and wheat prices did not show significant signs of nonlinear dynamics. From these results we infer a recent emergence of a scarcity price in global fertilizer markets, a result signaling a new high price regime for these essential agricultural inputs. Such a regime will challenge on-going efforts to establish global food security but may also prompt fertilizer use practices and nutrient recovery strategies that reduce eutrophication.

  13. Regime shift in fertilizer commodities indicates more turbulence ahead for food security.

    Directory of Open Access Journals (Sweden)

    James J Elser

    Full Text Available Recent human population increase has been enabled by a massive expansion of global agricultural production. A key component of this "Green Revolution" has been application of inorganic fertilizers to produce and maintain high crop yields. However, the long-term sustainability of these practices is unclear given the eutrophying effects of fertilizer runoff as well as the reliance of fertilizer production on finite non-renewable resources such as mined phosphate- and potassium-bearing rocks. Indeed, recent volatility in food and agricultural commodity prices, especially phosphate fertilizer, has raised concerns about emerging constraints on fertilizer production with consequences for its affordability in the developing world. We examined 30 years of monthly prices of fertilizer commodities (phosphate rock, urea, and potassium for comparison with three food commodities (maize, wheat, and rice and three non-agricultural commodities (gold, nickel, and petroleum. Here we show that all commodity prices, except gold, had significant change points between 2007-2009, but the fertilizer commodities, and especially phosphate rock, showed multiple symptoms of nonlinear critical transitions. In contrast to fertilizers and to rice, maize and wheat prices did not show significant signs of nonlinear dynamics. From these results we infer a recent emergence of a scarcity price in global fertilizer markets, a result signaling a new high price regime for these essential agricultural inputs. Such a regime will challenge on-going efforts to establish global food security but may also prompt fertilizer use practices and nutrient recovery strategies that reduce eutrophication.

  14. [Prolactin and male fertility].

    Science.gov (United States)

    Schreiber, G; Börner, A; Lauterbach, H; Thiel, W

    1983-03-01

    On 68 selected patients with disturbances of the potentia generandi et/sive coeundi (25 males with healthy metabolism and 43 males with diabetes) as well as 14 control persons PRL, LH, FSH, testosterone and oestradiol were determined radioimmunologically and the results were ascribed to sexological, clinical, spermatological and testo-histological findings. A statistically secure correlation was found between PRL values and disturbance of the libido as well as the presence of a gynaecomasty. PRL did not correlate with the spermatological variables volume of ejaculate, relative and absolute number of spermatozoa and motility. PRL did also not correlate with the testohistological findings. A relation between PRL and the peptide hormones LH and FSH as well as the steroid hormones testosterone and oestradiol could not be ascertained. Therefore the diagnostic values of a PRL determination is much limited; the pertinency of a hyperprolactinaemia may be increased by the proof of the symptoms reduction of libido and gynaecomasty with simultaneous disturbance of fertility. In our opinion the definition of hyperprolactinaemia needs revision, since at only determination of the basal value of more than 800 mU/l no more frequently pathologically andrological findings are to be observed than below 200 mU/l.

  15. Fertilization of SRC willow. II

    DEFF Research Database (Denmark)

    Sevel, L; Ingerslev, Morten; Nord-Larsen, Thomas

    2014-01-01

    Short rotation coppice (SRC) willow is an emerging cropping system in focus for production of biomass for energy. To increase production, the willow is commonly fertilized, but studies have shown differing effects of fertilization on biomass production, ranging from almost no response...... impacts of different doses of mineral fertilizer, manure and sewage sludge in a commercially grown SRC willow stand. We examined macro nutrient and heavy metal leaching rates and calculated element balances to evaluate the environmental impact. Growth responses were reported in a former paper (Sevel et al....... “Fertilization of SRC Willow, I: Biomass Production Response” Bioenergy Research, 2013). Nitrogen leaching was generally low, between 1 and 7 kg N ha−1 year−1 when doses of up to 120 kg N ha−1 year−1 were applied. Higher doses of 240 and 360 kg N ha−1 as single applications caused leaching of 66 and 99 kg N ha−1...

  16. Food security: Fertilizing hidden hunger

    Science.gov (United States)

    Müller, Christoph; Elliott, Joshua; Levermann, Anders

    2014-07-01

    Atmospheric CO2 fertilization may go some way to compensating the negative impact of climatic changes on crop yields, but it comes at the expense of a deterioration of the current nutritional value of food.

  17. IVF-In Vitro Fertilization.

    Science.gov (United States)

    Kieffer, George H.

    1980-01-01

    Issues surrounding the controversial topic of in vitro fertilization and artificial manipulation of reproduction are discussed. The author examines the moral and ethical implications and presents results of a survey of various religious groups. (SA)

  18. An analysis of social consequences of rapid fertility decline in China.

    Science.gov (United States)

    Liu, Z; Liu, L

    1988-12-01

    Rapid fertility decline in China has brought about 2 direct effects: 1) the natural increase of the population has slowed down, and 2) the age structure has changed from the young to the adult type. These 2 effects have caused a series of economic and social consequences. Rapid fertility decline increases the gross national product per capita and accelerates the improvement of people's lives. Rapid fertility decline slows population growth and speeds up the accumulation of capital and the development of the economy. Since 1981, accumulation growth has exceeded consumption growth. Fertility decline alleviates the enrollment pressure on primary and secondary schools, raises the efficiency of education funds, and promotes the popularization of education. The family planning program strengthens the maternal and child health care and the medical care systems. As the result of economic development, the people's nutritional levels are improving. The physical quality of teenagers has improved steadily. The change in the age structure will alleviate the tension of rapid population growth and benefit population control in the next century. Fertility decline forces the traditional attitude toward childbearing from "more children, more happiness" to improved quality of children. The rapid fertility decline has caused a great deal of concern both inside and outside China about the aging of the population. The labor force, however, will continue to grow for the next 60 years. At present, China's population problems are still those of population growth.

  19. The theoretical and political framing of the population factor in development.

    Science.gov (United States)

    Campbell, Martha; Bedford, Kathleen

    2009-10-27

    The silence about population growth in recent decades has hindered the ability of those concerned with ecological change, resource scarcity, health and educational systems, national security, and other global challenges to look with maximum objectivity at the problems they confront. Two central questions about population--(1) is population growth a problem? and (2) what causes fertility decline?--are often intertwined; if people think the second question implies possible coercion, or fear of upsetting cultures, they can be reluctant to talk about the first. The classic and economic theories explaining the demographic transition assume that couples want many children and they make decisions to have a smaller family when some socio-economic change occurs. However, there are numerous anomalies to this explanation. This paper suggests that the societal changes are neither necessary nor sufficient for family size to fall. Many barriers of non-evidence-based restrictive medical rules, cost, misinformation and social traditions exist between women and the fertility regulation methods and correct information they need to manage their family size. When these barriers are reduced, birth rates tend to decline. Many of the barriers reflect a patriarchal desire to control women, which can be largely explained by evolutionary biology. The theoretical explanations of fertility should (i) attach more weight to the many barriers to voluntary fertility regulation, (ii) recognize that a latent desire to control fertility may be far more prevalent among women than previously understood, and (iii) appreciate that women implicitly and rationally make benefit-cost analyses based on the information they have, wanting modern family planning only after they understand it is a safe option. Once it is understood that fertility can be lowered by purely voluntary means, comfort with talking about the population factor in development will rise.

  20. Impact of ART on the fertility of HIV-positive women in sub-Saharan Africa.

    Science.gov (United States)

    Yeatman, Sara; Eaton, Jeffrey W; Beckles, Zosia; Benton, Lorna; Gregson, Simon; Zaba, Basia

    2016-09-01

    Understanding the fertility of HIV-positive women is critical to estimating HIV epidemic trends from surveillance data and to planning resource needs and coverage of prevention of mother-to-child transmission services in sub-Saharan Africa. In the light of the considerable scale-up in antiretroviral therapy (ART) coverage over the last decade, we conducted a systematic review of the impact of ART on the fertility outcomes of HIV-positive women. We searched Medline, Embase, Popline, PubMed and African Index Medicus. Studies were included if they were conducted in sub-Saharan Africa and provided estimates of fertility outcomes (live births or pregnancies) among women on ART relative to a comparison group. Of 2070 unique references, 18 published papers met all eligibility criteria. Comparisons fell into four categories: fertility of HIV-positive women relative to HIV-negative women; fertility of HIV-positive women on ART compared to those not yet on ART; fertility differences by duration on ART; and temporal trends in fertility among HIV-positive women. Evidence indicates that fertility increases after approximately the first year on ART and that while the fertility deficit of HIV-positive women is shrinking, their fertility remains below that of HIV-negative women. These findings, however, were based on limited data mostly during the period 2005-2010 when ART scaled up. Existing data are insufficient to characterise how ART has affected the fertility of HIV-positive women in sub-Saharan Africa. Improving evidence about fertility among women on ART is an urgent priority for planning HIV resource needs and understanding HIV epidemic trends. Alternative data sources such as antenatal clinic data, general population cohorts and population-based surveys can be harnessed to understand the issue. © 2016 John Wiley & Sons Ltd.

  1. The Fertility Transition in Bavaria

    OpenAIRE

    Brown, John C.; Timothy W. Guinnane

    2001-01-01

    The decline of human fertility that occurred in Europe and North America in the nineteenth century, and elsewhere in the twentieth century, remains a topic of debate largely because there is no accepted explanation for the event. Disagreement persists in part because researchers have rarely used the detailed quantitative information necessary to form adequate tests of alternative theories. This paper uses district-level data from Bavaria to study the correlates of the decline of fertility in ...

  2. On economic-mathematical model for technology of differentiated application of fertilizers

    Directory of Open Access Journals (Sweden)

    Gennadiy Litchman

    2009-10-01

    Full Text Available The paper studies agricultural crops’ yield depending on quality of entering of mineral fertilizers. It is established that determining average productivity, under square-law dependence of yield on a dose, there is not necessity to set the law of fertilizers distribution across the field and will be sufficient to know expected value D and standard deviation sD. The paper considers approaches to economic-mathematical model of optimization of fertilizers’ doses at the differentiated entering. The produced result provides a new approach to the quality control in technological process of fertilizers application. Also, it allows formulating requirements to perspective technical means used for entering of mineral fertilizers.

  3. Association between fertilizer-mediated changes in microbial communities and Aedes albopictus growth and survival

    Science.gov (United States)

    Contamination of aquatic habitats with anthropogenic nutrients has been associated with an increase in mosquito larval populations but the underlying mechanisms remain poorly understood. We examined the individual and combined effects of two synthetic fertilizers (ammonium sulfate and potassium chlo...

  4. Children Procedures and Treatment (Fertility Issues)

    Science.gov (United States)

    ... approach the subject of fertility preservation with their cancer-stricken child? How is the Oncofertility Consortium addressing the fertility preservation needs of children? How do cancer and cancer treatment affect a child's fertility? Why should fertility preservation be a priority ...

  5. Fertilization and Embryo Development of Fresh and Cryopreserved Sibling Oocytes

    Directory of Open Access Journals (Sweden)

    Robert F. Casper

    2010-01-01

    Full Text Available Background: Oocyte cryopreservation is potentially the best way to preserve female fertility forunmarried women or young girls at risk of losing ovarian function. The aim of this study was tocompare fertilization and embryo development in frozen-thawed oocytes to their fresh siblings inwomen undergoing in vitro fertilization (IVF and embryo transfer (ET.Materials and Methods: Eleven infertile women undergoing infertility treatment, between theages of 24 to 37 years (mean ± SD = 31.6 ± 3.5, were included in this study. Mature oocytesfrom each patient were randomized into cryopreserved and fresh groups prior to intracytoplasmicsperm injection (ICSI. One hundred and thirty nine oocytes were retrieved, of which 105 were atmetaphase II (MII. Forty- five fresh MII oocytes were kept in culture whereas their sibling 60 MIIoocytes were cryopreserved using a slow cooling protocol. The frozen oocytes remained in LN2for 2 hours before thawing. ICSI was performed 1-2 hours after thawing for frozen oocytes and 4-5hours after retrieval for fresh oocytes. Fertilization and embryo development were compared.Results: Following thawing, 31 oocytes (51.6 % survived and 22 fertilized (79% while 32 freshoocytes fertilized upon ICSI (71%. The mean ± SE scores for embryos developing from frozenthawedoocytes were significantly lower at 48 and 72 hours post-ICSI than for embryos resultingfrom fresh oocytes (p<0.05.Conclusion: Our data demonstrated that oocyte freezing resulted in acceptable survival ratesfollowing cryopreservation, and similar fertilization rates following ICSI as compared to the freshsibling oocytes. However the number of blastomeres and the embryo quality on day three wassuperior in embryos from fresh oocytes when compared to the frozen oocytes.

  6. Immunization to regulate fertility: biological and cultural frameworks.

    Science.gov (United States)

    Schrater, A F

    1995-09-01

    Deliberate immunization to control fertility differs from that to control disease. Those differences can be discussed within various frameworks, e.g., intent, recipient population, biological bases, and immunological targets. Others include differing perspectives of developers, providers and users, and rights of the state to impose programs of control. Almost all of the differences are grounded in the social, economic, and gendered aspects of societies. The intent of providing a fertility-regulating vaccine is to prevent pregnancy. In theory, men as well as women could receive such vaccines; in reality, most are designed for women. Traditional vaccines are intended to prevent disease and are generally given to susceptible individuals whether male or female, child or adult. The biological bases of contraceptive vaccines are molecules specific to reproduction. The immune response generated by most anti-fertility vaccines is directed toward 'self', one's own cells and molecules. In contrast, the bases of traditional vaccines are materials derived from non-self, disease-causing microorganisms; the immunological targets are those microorganisms or their toxic products. From a developer perspective vaccines that regulate fertility differ little from those that control disease; both prevent a particular condition. Developers cite these advantages to contraceptive vaccines: non-invasive, no serious side-effects, easy to use, reduced patient failure, and long-lasting but naturally reversible. Because anti-fertility vaccines have been tested only in small-scale clinical trials, information on user reactions and experiences is limited. Not surprisingly, the perspectives of women's health advocates and of potential users (mostly women) often differ markedly from those of developers. Women cite as disadvantages the cryptic nature of immunity which leaves one without an obvious signal for the beginning of protection (against pregnancy) and its decline, and the inability to 'turn

  7. Changes in fertility and family sizes in Europe.

    Science.gov (United States)

    Pearce, D; Cantisani, G; Laihonen, A

    1999-01-01

    This article describes recent trends in annual fertility rates, and generation measurements of average family size and family size distributions for eight selected European Countries. It compares the changing ages at which mothers are having children and the decline in higher order births, both over time and between countries: The way that variations and changes in annual rates influence generation measurements is also illustrated. Finally, the article compares prevailing annual rates with the long-term fertility assumption included in the most recent population projections for seven countries.

  8. Improved fertility following conservative surgical treatment of ectopic pregnancy

    DEFF Research Database (Denmark)

    Bangsgaard, Nannie; Lund, Claus Otto; Ottesen, Bent

    2003-01-01

    OBJECTIVE: To evaluate fertility after salpingectomy or tubotomy for ectopic pregnancy. DESIGN: Retrospective cohort study. SETTING: Clinical University Center, Hvidovre Hospital, Copenhagen. POPULATION: Two hundred and seventy-six women undergoing salpingectomy or tubotomy for their first ectopic...... pathology, the chance of pregnancy was poor (hazard ratio 0.463) and the risk of recurrence was high (hazard ratio 2.25), assessed with Cox regression. The rate of persistent ectopic pregnancy was 8%. CONCLUSION: Conservative surgery is superior to radical surgery at preserving fertility. Conservative...

  9. [[Trends in marriage and fertility in Japan: major findings from the Tenth Japanese National Fertility Survey

    Science.gov (United States)

    Atoh, M; Takahashi, S; Nakano, E; Watanabe, Y; Kojima, H; Kaneko, R

    1993-10-01

    The authors review trends in marriage and fertility in Japan, using data from the 1993 Japanese National Fertility Survey. Information is included on age at marriage, arranged and voluntary marriages, length of time from initial meeting to marriage, changes in age at marriage, fertility, socioeconomic differentials in fertility, and fertility preferences. (SUMMARY IN ENG)

  10. Estabilidade da população de perfilhos de capim-marandu sob lotação contínua e adubação nitrogenada Stability of tiller population of continuously stocked marandu palisade grass fertilized with nitrogen

    Directory of Open Access Journals (Sweden)

    Fábio Olegário Caminha

    2010-02-01

    Full Text Available O objetivo deste trabalho foi avaliar a sobrevivência e a estabilidade da população de perfilhos em pastos de capim-marandu (Brachiaria brizantha submetidos �� lotação contínua e à adubação nitrogenada. Os tratamentos corresponderam a três doses de nitrogênio (150, 300 e 450 kg ha-1 mais o controle (sem adubação, e as unidades experimentais (piquetes de 1.200 m² foram dispostas segundo um delineamento de blocos completos ao acaso, com quatro repetições. Foram avaliados mensalmente as taxas de sobrevivência, o balanço entre morte e aparecimento de perfilhos entre morte e aparecimento de perfilhos e o índice de estabilidade da população de perfilhos, de janeiro de 2007 a abril de 2008, em cinco épocas. A taxa de sobrevivência, o balanço entre morte e aparecimento e o índice de estabilidade da população de perfilhos variaram com as épocas do ano. Pastos que receberam 450 kg ha-1 de N apresentaram as menores taxas de sobrevivência no verão, contudo, mantiveram a estabilidade da população. Maiores doses de N possibilitam alcançar balanço positivo entre aparecimento e morte de perfilhos mais rapidamente no fim da primavera. O nitrogênio favorece a renovação de plantas e mantém a estabilidade da população de perfillhos desde que fatores como temperatura e precipitação não sejam limitantes.The objective of this work was to evaluate the survival and stability of tiller population on marandu palisade grass (Brachiaria brizantha swards subjected to continuous stocking and to fertilization with nitrogen. Treatments corresponded to three nitrogen doses (150, 300 and 450 kg ha-1 plus control (no fertilization, and the experimental units (1,200-m² paddocks were placed according to a randomized complete block design, with four replicates. Survival rates, balance between tiller death and appearance and tiller population stability indexes were evaluated monthly from January 2007 to April 2008, in five seasons

  11. Weighted Mean Impact Analysis

    OpenAIRE

    Burger, Svenja

    2015-01-01

    Linear regression is a popular tool that is often applied to biometric and epidemiological data. It relies on strong model assumptions that are rarely satisfied. To overcome this difficulty, Brannath and Scharpenberg (2014) proposed a new population based interpretation of linear regression coefficients. The idea is to quantify how much the unconditional mean of the dependent variable Y can be changed by changing the distribution of the independent variable X. The maximum change is called "me...

  12. Modeling the Effect of Oil Price on Global Fertilizer Prices

    NARCIS (Netherlands)

    P-Y. Chen (Ping-Yu); C-L. Chang (Chia-Lin); C-C. Chen (Chi-Chung); M.J. McAleer (Michael)

    2010-01-01

    textabstractThe main purpose of this paper is to evaluate the effect of crude oil price on global fertilizer prices in both the mean and volatility. The endogenous structural breakpoint unit root test, the autoregressive distributed lag (ARDL) model, and alternative volatility models, including the

  13. Integrated soil fertility management: Policy and best practice document 7

    OpenAIRE

    Hilhorst, T. (ed.); Toulmin, C.

    2000-01-01

    Metadata only record This policy and best practice document focuses on ways to promote integrated soil fertility management in developing countries, particularly by smallholders working under rainfed conditions. We aim, by this means, to contribute to more sustainable agriculture which is vital to achieving food security, poverty alleviation and environmental protection. All of these are important objectives of the Netherlands' development cooperation policy.

  14. Edxrf determination of major and minor elements in compound fertilizers

    DEFF Research Database (Denmark)

    Christensen, Leif Højslet; Rasmussen, Leif W.

    1985-01-01

    The combination of the energy-dispersive x-ray fluorescence technique and a backscatter/fundamental parameter-based matrix correction approach provides a new and unique solution to elemental analyses of fertilizers. This is demonstrated by means of results obtained for three reference materials...

  15. BRCA Mutations Increase Fertility in Families at Hereditary Breast/Ovarian Cancer Risk.

    Directory of Open Access Journals (Sweden)

    Fabrice Kwiatkowski

    Full Text Available Deleterious mutations in the BRCA genes are responsible for a small, but significant, proportion of breast and ovarian cancers (5 - 10 %. Proof of de novo mutations in hereditary breast/ovarian cancer (HBOC families is rare, in contrast to founder mutations, thousands of years old, that may be carried by as much as 1 % of a population. Thus, if mutations favoring cancer survive selection pressure through time, they must provide advantages that compensate for the loss of life expectancy.This hypothesis was tested within 2,150 HBOC families encompassing 96,325 individuals. Parameters included counts of breast/ovarian cancer, age at diagnosis, male breast cancer and other cancer locations. As expected, well-known clinical parameters discriminated between BRCA-mutated families and others: young age at breast cancer, ovarian cancer, pancreatic cancer and male breast cancer. The major fertility differences concerned men in BRCA-mutated families: they had lower first and mean age at paternity, and fewer remained childless. For women in BRCA families, the miscarriage rate was lower. In a logistic regression including clinical factors, the different miscarriage rate and men's mean age at paternity remained significant.Fertility advantages were confirmed in a subgroup of 746 BRCA mutation carriers and 483 non-carriers from BRCA mutated families. In particular, female carriers were less often nulliparous (9.1 % of carriers versus 16.0 %, p = 0.003 and had more children (1.8 ± 1.4 SD versus 1.5 ± 1.3, p = 0.002 as well as male carriers (1.7 ± 1.3 versus 1.4 ± 1.3, p = 0.024.Although BRCA mutations shorten the reproductive period due to cancer mortality, they compensate by improving fertility both in male and female carriers.

  16. Fertility, immigration, and the fight against climate change.

    Science.gov (United States)

    Earl, Jake; Hickey, Colin; Rieder, Travis N

    2017-10-01

    Several philosophers have recently argued that policies aimed at reducing human fertility are a practical and morally justifiable way to mitigate the risk of dangerous climate change. There is a powerful objection to such "population engineering" proposals: even if drastic fertility reductions are needed to prevent dangerous climate change, implementing those reductions would wreak havoc on the global economy, which would seriously undermine international antipoverty efforts. In this article, we articulate this economic objection to population engineering and show how it fails. We argue, first, that the economic objection paints an inaccurate picture of the complicated relationship between demographic change and economic growth, and second, that any untoward economic effects of fertility reduction can be mitigated with additional policies. Specifically, we argue that supplementing fertility reduction with policies that facilitate the emigration of younger people from developing nations to developed nations could allow for both global reductions in GHG emissions and continued economic stability. Further, we show that moral arguments against such unprecedented increases in immigration are unsuccessful. We conclude that population engineering is a practical and morally justifiable tool for addressing the twin evils of climate change and global poverty. © 2017 John Wiley & Sons Ltd.

  17. Patriarchy and fertility in Albania

    Directory of Open Access Journals (Sweden)

    Mathias Lerch

    2013-07-01

    Full Text Available BACKGROUND Theories of fertility collapse in the post-socialist era imply a decline in the moral primacy of traditional social institutions. Yet gender inequality actually increased in many countries, and there is a scarcity of empirical evidence for the role played by traditional social institutions in reproductive decision-making. OBJECTIVE We investigate whether patriarchal institutions sustained the fertility levels in Albania. The geography of marriage and family enlargement is related to the importance of patriarchy in kinship organisation and in the public sphere. To account for this spatial relationship we test the evidence for different pathways in patriarchal influence on reproductive decision-making including social effects, socialisation in patriarchal ideals, and the promotion of male fertility. METHODS We reconstruct reproductive histories from the 2001 Census and use data on attitudes and fertility intentions from the Reproductive and Health Survey 2002. Multilevel logistic regressions on marriage and (the intention of higher order births are used. RESULTS A majority of women endorsed patriarchal ideals and fertility transition was less advanced in more patriarchal municipalities. Patriarchal kinship organisation promoted early marriages and high fertility, which is shown to be achieved by social learning among peers and intergenerational social influences respectively, as well as by women's socialisation and a stopping behaviour in childbearing dominated by son-preference. Although gender inequality in the public sphere has also sustained the level of fertility and decreased the risk of marriage, it was not accounted for by these pathways of patriarchal influence. CONCLUSIONS Despite Albania's gradual opening to the world in a period of economic and political crisis, traditional social institutions remain important for family behaviours.

  18. Fertility preservation options for prepubertal boys facing gonadotoxic therapies.

    Science.gov (United States)

    Hussein, Ahmed A; Yango, Pamela; Ezz, Youseff; Smith, James F; Tran, Nam D

    2016-12-01

    Infertility is a common disease affecting 10-15% of reproductive couples with significant psychological and financial impacts to both patients and society. Approximately 80 million people worldwide are infertile, with an increasing incidence of male infertility. Semen cryopreservation in adults is a proven method of fertility preservation for male patients undergoing gonadal toxic therapies. Unlike adults who can cryopreserve sperm at any time prior to gonadal toxic treatments, there are no effective fertility preservation options for children undergoing cancer treatment, a time when semen cryopreservation is not feasible. Thus, most of the childhood cancer survivor will develop irreversible azoospermia due to the gonadal toxicity of the treatment on spermatogononial stem cells. This review will summarize the possible options and challenges of fertility preservation in this vulnerable population.

  19. A RCK Model with Endogenous Fertility and Exogenous Technological Change

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The technological change as an exogenous variable is introduced into the RCK model with endogenous fertility in this paper. It is proved that the model has at least a nonzero steady state and the nonzero steady state is unique when the parameters satisfies some conditions. By phrase protrait analysis, the unique nonzero steady state is saddle and the economy has a unique optimal growth path. The results obtained implies that the relationship between the technological change and population growth rate determinated by the economic structure and the parental ethies. For the economy in which the parents is selfish, promoting the technologlcal change rate decreases the fertility at the steady state. On the other hand, for the economy in which the parents is less selfish, the fertility increases as the technological change rate increases.

  20. [Models of economic theory of population growth].

    Science.gov (United States)

    Von Zameck, W

    1987-01-01

    "The economic theory of population growth applies the opportunity cost approach to the fertility decision. Variations and differentials in fertility are caused by the available resources and relative prices or by the relative production costs of child services. Pure changes in real income raise the demand for children or the total amount spent on children. If relative prices or production costs and real income are affected together the effect on fertility requires separate consideration." (SUMMARY IN ENG)

  1. Genetics of Fertility Restoration in Cytoplasmic Male Sterile Pepper

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Pepper hybrid seeds production using male sterility could lower cost by reducing time and labour, and increase the genetic purity of the F1 seeds. To investigate the genetics of fertility restoration of the Peterson cytoplasmic sterility in pepper, a doubled haploid population of 115 pepper lines obtained from anther culture of the F1 hybrid between Yolo Wonder (sterility maintainer line) and Perennial (fertility restorer line) and the parental lines were test-crossed by 77013A (a strict cytoplasmic-genic male sterile line). The fertility of the test-crossed lines was assessed in greenhouse and open field with the following three criteria: pollen index (PI, visual estimation of pollen amount per flower), pollen number (PN, pollen counting under microscope), and seed number (SN, the number of seeds per fruit in open pollination). Correlations between the each couple of criteria within, as well as between the cultivation methods ranged from 0.55 to 0.84. Analysis of variance showed that the genotype (DH line) and environment were the significant sources of variation of the fertility.Narrow sense of heritance of fertility restoration ranged from 0.38 to 0.92, depending on the criteria and environment. The distribution of the progeny was continuous between the parental genotypes indicating the quantitative inheritance of fertility restoration. Inferred from segregation according to Snape et al.(1984), the number of segregating genes was estimated to be that three to four genetic factors were involved in pollen traits (PI and PN) and five to eight genetic factors in seed production (SN). The heredity analysis of the CMS will be helpful for understanding of the genetic mechanism of the fertility restoration and the exploitation of the CMS in hybrid seed production.

  2. Primogeniture and fertility: fertility models with unequal bequest.

    Science.gov (United States)

    Parsons, D O

    1984-01-01

    Models of the family which incorporate bequest inequality into the fertility decision were developed. Following a discussion on this topic by H.J. Habakkuk, discussion focuses on preindustrial and early industrial England and Western Europe. An attempt was made to develop fertility models which do not assume that all children are treated equally but instead recognize the special role that the eldest child often plays in the family. The fertility consequences of primogeniture are explored in 2 different fertility models. In the initial behavioral model due to Habakkuk, fertility is a function of marriage age and marriage age is a function of time required for one's capital to reach some social minimum required for household formation. In such a model it is possible to show that an increasingly unequal bequest between children will reduce aggregate fertility in the following generation. The introduction of explicit fertility choice considerably complicates the model. The effect of greater relative bequests to the eldest child, if motivated by parental preference, depends on the role children other than the eldest play in the family. If parents would normally choose to have more children the larger the total bequest they intend to bestow on all their children, the effect of primogeniture will be to reduce fertility. The wealth parents allocate to the eldest with primogeniture has an impact on the other children equivalent to a general decline in family bequests. Similar conclusions hold if the shift of wealth to the eldest is the result of a legal constraint that a specified share of the estate be allocated to the eldest. Yet, if the constraint is posed as a required proportionality between the wealth of the eldest and the average wealth of other children, the effect of primogeniture laws (or conversely equality laws) is ambiguous. The same negative wealth effect exists for the younger children as wealth is diverted to the eldest. A positive fertility effect also

  3. Analyzing indicator microorganisms, antibiotic resistant Escherichia coli, and regrowth potential of foodborne pathogens in various organic fertilizers.

    Science.gov (United States)

    Miller, Cortney; Heringa, Spencer; Kim, Jinkyung; Jiang, Xiuping

    2013-06-01

    This study analyzed various organic fertilizers for indicator microorganisms, pathogens, and antibiotic-resistant Escherichia coli, and evaluated the growth potential of E. coli O157:H7 and Salmonella in fertilizers. A microbiological survey was conducted on 103 organic fertilizers from across the United States. Moisture content ranged from approximately 1% to 86.4%, and the average pH was 7.77. The total aerobic mesophiles ranged from approximately 3 to 9 log colony-forming units (CFU)/g. Enterobacteriaceae populations were in the range of fertilizer, respectively, whereas E. coli O157:H7 grew approximately 4.6, 4.0, 4.0, and 4.8 log CFU/g, respectively. Our results revealed that the microbiological quality of organic fertilizers varies greatly, with some fertilizers containing antibiotic resistant E. coli and a few supporting the growth of foodborne pathogens after reintroduction into the fertilizer.

  4. [Population education].

    Science.gov (United States)

    Niang, M

    1992-12-01

    Africa has the highest population growth rate in the world (3%). It has 650 million people (about 900 million in 2000). Rapid population growth has serious consequences which, if not addressed, will be disastrous. This worrisome situation has led some governments to adopt demographic policies to slow down population growth. The UN Economic, Scientific and Cultural Organization (UNESCO) recommends that schools provide population education. Various population conferences have popularized population education in schools among African countries. UNESCO began its regional program on population education in Africa in 1969. National family life and population education (FL/PE) projects have increased from 4 in 1970 to 32 in 1990 (17 in French- and Portuguese-speaking Africa and 5 in English-speaking Africa). These projects teach students about the links between demographic problems and socioeconomic factors and contemporary culture. They aim for total development of the individual and improvement of the quality of life for the individual, family, and community. Topics covered in FL/PE are birth rate; fertility; health; and maternal, infant, and child mortality; unwanted pregnancy; illegal abortion; sexually transmitted diseases; rural-urban migration; and urbanization. Benin introduced FL/PE at all levels of its education system while Senegal, Guinea, Mauritania, and Zaire introduced it to only the primary and secondary school levels. Some countries teach FL/PE as one discipline while most countries (e.g., Senegal) have integrated it into other disciplines (e.g., geography). FL/PE should begin in primary schools because they have the most students and prepare students for middle schools, which provide FL/PE. Elementary education in Senegal is being overhauled to introduce current major problems bit by bit. Senegal also wants to incorporate FL/PE into literacy and adult education programs. Integration of FL/PE into other disciplines should be encouraged.

  5. In situ polymerization coating and characteristics of coated NPK compound fertilizer

    Institute of Scientific and Technical Information of China (English)

    WANG Zhenghui; ZHU Homing

    2007-01-01

    Controlled release NPK compound fertilizers were prepared by means of in situ polymerization of monomers on the surface of fertilizer granules at room temperature. Methacrylate, α-methyl acrylic acid, and ethylene dimethylacrylate were used as monomers, Dibenzoyl peroxide as initiator, and cobalt naphthenate, and triethyl amine as promoters. The structures of coating materials were characterized by IR spectra. The thermogravimetric analysis result indicated that the coating materials were of good thermal stability. The mean thickness of single coating measured with screw gauge was ca. 140 μm. The morphologies of uncoated and coated fertilizer granules analyzed by using scanning electron microscopy were changed from porosities and gullies to hills and plain. The release rate of coated compound fertilizers in water could be controlled by the hydrophicity and thickness of coating. The increase in coating hydrophicity caused the increase in release rate of fertilizer. The increase in thickness of coating slowed the release rate.

  6. The story of a 'maverick': Bulgaria's fertility decline.

    Science.gov (United States)

    Botev, N

    1995-01-01

    Analysis of the fertility decline in Bulgaria shows that the perception of Bulgaria as an 'anomaly' in terms of its demographic development is based on a conservative interpretatiion of the demographic transition theory. The features that distinguish Bulgaria from the western European countries (faster decline, persistence of early and universal marriages, etc.) are generally accounted for by the specific social, economic, cultural, and political conditions. These findings suggest that the speed of the fertility decline and the means through which it is achieved are affected by a complex interaction between cultural and economic factors that are often difficult to distinguish in terms of primacy.

  7. Fertilization and early seed formation.

    Science.gov (United States)

    Dumas, Christian; Rogowsky, Peter

    2008-10-01

    The double fertilization of flowering plants is a complex process, encompassing multiple steps. From its discovery more than a century ago, many useful descriptive approaches have been employed to better unveil specific steps/mechanisms. More recently, the development of an in vitro assay developed in our laboratory, has allowed a better understanding of this phenomenon. However, in vitro methods may show some limitations. The search for complementary strategies, especially with the search of mutants affected in the fertilization step allowed one to elucidate this critical and unique phenomenon in living organisms. Genes involved in pollen tube guidance or pollen discharge in synergids have been identified, as well as genes exhibiting differential expression in sperm, egg and central cells before and after fertilization. A calcium wave proved to correspond to the first cellular event seen after cytoplasmic fusion in the fertilized egg cell or zygote, which develops into a multi-cellular organism with an elaborate body plan. The development of the fertilized central cell into a nourishing tissue (endosperm) starts with the formation of the coenocyte, a multinuclear single cell unique in the plant kingdom, cellularization occurring later on. The balance of the paternal and maternal genomes, which is under the control of the FIS polycomb group complex, was found to be of the utmost importance for the successful development of the seed.

  8. Transition cow: interaction with fertility.

    Science.gov (United States)

    Formigoni, A; Trevisi, E

    2003-09-01

    In recent years a progressive worsening of fertility indices in dairy cow herds has been observed. Several factors (genetic, dietary and management) seem to be more related to poor fertility than milk yield level. The degree and the length of the energy deficit during the transition period are inversely related to reproductive indices (e.g. conception rate is fertility in several ways. Excess of rumen degradable proteins, apart from negative energy balance, negatively affects reproductive activity. Conversely, some nutrients (i.e. some polyunsaturated fatty acids or some amino acids) seem to show positive effects on fertility. Finally, the relationship between health status, often compromised during the transition period, and fertility efficiency is discussed. The release of cytokines seems to be related directly and indirectly (mainly by the change in usual hepatic metabolism to the malfunction of reproductive apparatus. Quick recovery of reproductive activity requires the adoption of strategies around calving to cover the higher environmental and nutritive requirements and to prevent disorders of any kind.

  9. Fertility preservation in Turner syndrome.

    Science.gov (United States)

    Grynberg, Michaël; Bidet, Maud; Benard, Julie; Poulain, Marine; Sonigo, Charlotte; Cédrin-Durnerin, Isabelle; Polak, Michel

    2016-01-01

    Premature ovarian insufficiency is a relatively rare condition that can appear early in life. In a non-negligible number of cases the ovarian dysfunction results from genetic diseases. Turner syndrome (TS), the most common sex chromosome abnormality in females, is associated with an inevitable premature exhaustion of the follicular stockpile. The possible or probable infertility is a major concern for TS patients and their parents, and physicians are often asked about possible options to preserve fertility. Unfortunately, there are no recommendations on fertility preservation in this group. The severely reduced follicle pool even during prepubertal life represents the major limit for fertility preservation and is the root of numerous questions regarding the competence of gametes or ovarian tissue crybanked. In addition, patients suffering from TS show higher than usual rates of spontaneous abortion, fetal anomaly, and maternal morbidity and mortality, which should be considered at the time of fertility preservation and before reutilization of the cryopreserved gametes. Apart from fulfillment of the desire of becoming genetic parents, TS patients may be potential candidates for egg donation, gestational surrogacy, and adoption. The present review discusses the different options for preserving female fertility in TS and the ethical questions raised by these approaches.

  10. Population growth is a variable open to change

    Science.gov (United States)

    Potts, M.

    2016-12-01

    The absolute number of people and the rate of population growth have an impact on climate mitigation, adaptation and possible conflict. Half the pregnancies in the US are unintended. Robust quantitative evidence from California demonstrates that improving access to family planning is the single most cost-effective way of mitigating our carbon footprint. Globally, there are 80 million unintended pregnancies annually. Many non-evidence barriers deprive women of the information and means required to separate sex from childbearing. Between 1960 and 1990, meeting the need for family planning led to a rapid fall in family size in much of Asia. Since 1990, funding for family planning has collapsed and fertility decline has stalled. The UN projects that by 2100 global population will increase by 3.8 billion (equal to world population in 1975). 80% of this growth will be in Africa. Studies project that climate change will undermine crop yields in parts of Africa, especially the Sahel. A high ratio of young males to the rest of the population is a risk factor in conflict. Today, only 1% of overseas assistance is allocated to family planning. Based on analysis of the past, doubling that investment would accelerate fertility decline, facilitating climate mitigation and adaptation, and possibly reducing conflict. Population and family planning were pushed off the international agenda by unacceptably and tragic episodes of coercion in China and India. However, there is compelling data that when voluntary family planning is widely available then family size can fall rapidly, as occurred in the Islamic Republic of Iran, where fertility fell more rapidly than in any other country in history. Family planning is listening to what women want not telling people want to do. Population growth is a variable open to change in a human rights framework. Population and family planning are variables relevant to the scientific agenda of the AGU.

  11. Marital status and fertility of 185 male renal transplant recipients in China.

    Science.gov (United States)

    Xu, Long-Gen; Wang, Hong-Wei; Peng, Wang-Ling; Jin, Li-Ming; Zhu, Xiao-Feng; Xu, Hui-Ming; Song, Qi-Zhe; Xu, Biao; Ding, Xian-Fan

    2008-01-01

    A questionnaire was designed to assess the effects of renal transplantation in men of reproductive age on marital status and fertility. The study sought to correlate recipients' marital status and fertility with the health of the recipients after the transplantation, the health of children they fathered after the procedure, and the functioning of the transplanted kidney. Male recipients (n = 243) who were single and of reproductive age before renal transplantation were selected from 2007 recipients of a renal transplant recorded in the authors' hospitals in China. Of the 243 surveyed, 185 completed the questionnaire and participated in follow-up in the clinic or by telephone. Their marital status and fertility were investigated. Of the 185 recipients, 69 got married 12-88 months (mean, 32.19 +/- 14.30 months) after renal transplantation, and 62 of 69 couples were actively attempting to become pregnant. Fifty-three patients fathered 54 children, including 1 pair of twins, 9-72 months (mean, 25.81 +/- 15.33 months) after marriage. The birth weights of the newborns ranged from 2500 to 4600 g (mean, 3395 +/- 456.80 g). These children developed well. Nine patients did not father any children, and 3 of these 9 cases were attributable to infertility in the wife. Seven patients were using contraceptives. Three recipients suffered from chronic graft rejection and resumed hemodialysis 2-11 years after they fathered children. In addition, 2 patients died after fathering 1 child: 1 from dysfunction of the transplanted kidney 9 years after birth of his child, and another in an accident 1 year after his child's birth. Our findings suggest that, like men without renal transplants, male recipients of renal transplants can get married and father children, and the transplantation procedure appears to have no significant effect on the children fathered afterwards, on the recipients' health, or on the functioning of the transplanted kidney. It is very important to indicate that, in

  12. Status of fertility control in Egypt.

    Science.gov (United States)

    Hefnawi, F I

    1982-01-01

    The concern for fertility control is not alien to the cultural and religious heritage of Egypt. Historically, Egyptian interest in fertility dates to the Pharoahs. Contraceptive recipes written at least 15-18 centuries B.C. have been found. Romans may have borrowed some of the more effective methods from Egypt when it became part of the Roman Empire as evidenced by the decline in size of aristocratic Roman families at the beginning of the Christian era. Muslim conquerors of Egypt encouraged fertility control. In the 9th century differences of opinion about the legality of contraception appeared among the interpreters of Islamic law. Some methods found in the writings of Muslim doctors as al-Razi and Avicenna still survive in the folk medicine of Egypt. In modern times use of barrier methods of contraception were encouraged by family planning organizations in Egypt. The medical profession was not deeply involved since these methods did not require much medical assistance. In 1936 a religiouss verdict declared contraception to be a lawful act of Islam. National programs in family planning in the 1960's encouraged the use of the Lippes Loop IUD. The medical problem of blood loss associated with the IUD caused anxiety because of the high incidence of anemia in the female Egyptian population. There was also a cultural limitation on the wide use of the IUD. "Spotting" due to the IUD resulted in females being ritually unclean and therefore unfit to pray or observe the Islamic fast. The Pill, initially favored caused complications due to its effect on breast milk which is the universal source of nutrition for infants in Egypt. Replacement of the Pill by depo-provera injections during the post partum period of lactation is a practical solution. Permanent sterilization is limited to females and only performed when medically indicated. Abortion is illegal and permitted only as a therapeutic measure.

  13. [Social differentials of fertility in Latin America and Mexico].

    Science.gov (United States)

    Tuiran, R

    1991-01-01

    Analysis of fertility differentials has been utilized for 3 different purposed in sociodemographic research: as an exploratory procedure designed to identify the principal determinants of reproductive behavior; as a strategy to describe and interpret the process of fertility decline and identify the sectors leading the change; and as a means of projecting future fertility trends. The systematic study of differential fertility began in Mexico and Latin America in the late 1950s, following the models of European and North American research guided by theories of modernization and the demographic transition. Latin American studies attempted to verify the existence of differences in reproductive behavior according to certain socioeconomic characteristics, assuming that the sectors most fully incorporated in the processes of modernization and development would lead the fertility decline. Studies in Mexico have demonstrated that total fertility rates decrease systematically as the size of the place of residence increases and as the level of education increases, although the association with education is not strictly lineal. Various studies have confirmed that economically active women have lower fertility than inactive women, although cross-sectional analyses have had little success in establishing the direction of causality. Evidence exists that in Mexico as elsewhere the initial stage in the transition is accompanied by an increase in the absolute and/or relative magnitude of fertility differences among women in the extreme categories of residence, education, or employment. The magnitude of the differences declines as the transition progresses. Using the method proposed by Bongaarts or 1 of its variants, different studies have emphasized the importance of contraception and nuptiality as factors in total fertility rate differentials by socioeconomic characteristics. The theoretical and methodological limitations of differential analysis should not be overlooked. A common

  14. The fertility incentive of land tenure in Mexico.

    Science.gov (United States)

    Soberon-ferrer, H; Whittington, L A

    1993-12-01

    Ejidos are communal holding groups of redistributed land expropriated (generally without compensation) from large private landowners during Mexico's post-1910 land reform. The model in this study of the "ejidal" system's influence on fertility differs from DeVany and Sanchez in providing more current data and including the following more detailed variables: the land area of ejidos and the number of ejidos, the need for children, male income, female income share, and social security coverage. The data pertains to states rather than municipalities. DeVany and Sanchez found that the ejidal system encouraged fertility, because having more children helped an ejido family retain land rights, increased its chances of gaining additional productive land, and gave it increased political power. Children also provided a means of intergenerational transfer of resources. The estimation results of this study revealed that the total proportion of land held as ejidos had a positive, significant effect on fertility. The ratio of ejidos to total number of farms was negative and significant. There was support for the hypothesis that the impact of ejidos land holdings and area was diminished when ejidos were dominant in the state. Fertility declined with the increase in unpaid workers per hectare of land. Elasticity functions were small: 0.075 on ejidal land, -0.222 on ejidal farms, and -0.045 on workers. A positive significant demographic effect on fertility was illiteracy. Infant mortality and female income share each had a negative, significant effect on fertility. Insignificant variables were male income, social security coverage, and the dummy for northern states. There have been changes in the Mexican ejidal system. These changes and the availability of farm labor are expected to reduce urban and rural fertility differentials.

  15. Male fertility in Greece: Trends and differentials by education level and employment status

    Directory of Open Access Journals (Sweden)

    Alexandra Tragaki

    2014-07-01

    Full Text Available Background: More than downplayed, the role of men in the demographic analysis of reproduction has been entirely neglected. However, male fertility can be an important issue for exploring how economic and employment uncertainties relate to fertility and family